WO1998038708A1 - Lighting apparatus for discharge lamps and discharge lamp socket used therein - Google Patents

Lighting apparatus for discharge lamps and discharge lamp socket used therein Download PDF

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Publication number
WO1998038708A1
WO1998038708A1 PCT/US1998/003594 US9803594W WO9838708A1 WO 1998038708 A1 WO1998038708 A1 WO 1998038708A1 US 9803594 W US9803594 W US 9803594W WO 9838708 A1 WO9838708 A1 WO 9838708A1
Authority
WO
WIPO (PCT)
Prior art keywords
discharge lamp
socket
housing
movable unit
unit
Prior art date
Application number
PCT/US1998/003594
Other languages
French (fr)
Inventor
Ping Chen
Kimihiro Miyaki
Original Assignee
The Whitaker Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP6200597A external-priority patent/JP3416015B2/en
Application filed by The Whitaker Corporation filed Critical The Whitaker Corporation
Priority to AU64385/98A priority Critical patent/AU6438598A/en
Publication of WO1998038708A1 publication Critical patent/WO1998038708A1/en

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/288—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices and specially adapted for lamps without preheating electrodes, e.g. for high-intensity discharge lamps, high-pressure mercury or sodium lamps or low-pressure sodium lamps
    • H05B41/292—Arrangements for protecting lamps or circuits against abnormal operating conditions
    • H05B41/2921—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions
    • H05B41/2925—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions against abnormal lamp operating conditions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/10—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by the light source
    • F21S41/14—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by the light source characterised by the type of light source
    • F21S41/17—Discharge light sources
    • F21S41/172—High-intensity discharge light sources
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/10—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by the light source
    • F21S41/19—Attachment of light sources or lamp holders
    • F21S41/192—Details of lamp holders, terminals or connectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V25/00—Safety devices structurally associated with lighting devices
    • F21V25/02—Safety devices structurally associated with lighting devices coming into action when lighting device is disturbed, dismounted, or broken
    • F21V25/04—Safety devices structurally associated with lighting devices coming into action when lighting device is disturbed, dismounted, or broken breaking the electric circuit
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R33/00—Coupling devices specially adapted for supporting apparatus and having one part acting as a holder providing support and electrical connection via a counterpart which is structurally associated with the apparatus, e.g. lamp holders; Separate parts thereof
    • H01R33/945—Holders with built-in electrical component
    • H01R33/955—Holders with built-in electrical component with switch operated manually and independent of engagement or disengagement of coupling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/46—Bases; Cases
    • H01R13/53—Bases or cases for heavy duty; Bases or cases for high voltage with means for preventing corona or arcing

Definitions

  • This invention relates to sockets for discharge lamps for motor vehicle headlights and lighting apparatus for such lamps.
  • gas discharge lamps are distinguished by high brightness, lower power consumption, small size and long life. Because of these advantages, it is expected that these lamps will eventually replace halogen and incandescent lamps currently used in vehicle head lights.
  • some car owners especially in Western Europe, find it desirable to replace discharge lamps on their own. Since a high voltage is applied to the discharge lamp through an igniter, it is desirable to provide an apparatus protecting the car owners or repairmen replacing discharge lamps from electric shock.
  • the discharge lamp unit 100 comprises a discharge lamp 102 and a terminal unit 104.
  • the terminal unit 104 has three post terminals 106, 108, 110.
  • Two terminals 108, 110 are regular terminals for power supply.
  • Socket 120 for the discharge lamp has receptacle terminals 122, 124, 126 mating with the three post terminals 106, 108 and 110.
  • two terminals 106, 108 of the discharge lamp unit 100 are connected to a high-voltage starting circuit 130 of discharge lamp 102, and the common terminal 110 is connected to an overvoltage protection circuit 132.
  • the overvoltage-protection circuit 132 detects whether the discharge lamp unit 100 is connected to the high-voltage starting circuit 130 of discharge lamp 102 via the terminal 126 or not. This circuit blocks the generation of high voltage by the high-voltage starting circuit 130 of discharge lamp 102 if the discharge lamp unit 100 is not inserted in the discharge lamp socket 120, thus preventing the worker from electric shock.
  • Japanese Application is designed to accommodate special discharge lamps having three terminals. Because of this, they cannot be used with present standard two-terminal discharge lamps, and discharge lamps and sockets having three terminals did not receive wide acceptance in the market.
  • the discharge lamp must be operated by high voltage and its lighting apparatus must be thoroughly shielded because they generate magnetic interference.
  • no measures against magnetic interference are offered in the socket and the surrounding apparatus described in the above Japanese
  • a faulty shield around the socket and surrounding apparatus can result in dangerously high voltage applied to unrelated equipment.
  • the first purpose of this invention is to offer a lighting apparatus and a socket for discharge lamps which would make it possible to prevent electric shock at the time of replacement of standard discharge lamps having two terminals by preventing the generation of high voltage.
  • the other purpose of this invention is to offer a socket for discharge lamps and a lighting apparatus using such a socket which prevents generation of high voltage in the event the shield is faulty.
  • a lighting apparatus for discharge lamps comprises a socket receiving a discharge lamp and a power supply providing power to the socket wherein the socket has a switching means comprised of a movable unit accepting the discharge lamp which can rotate relative to a housing of the socket between a position at which the discharge lamp is inserted and a position at which the discharge lamp is fully secured in the socket, which switching means is actuated when the movable unit is turned to the position at which the discharge lamp is fully secured in the socket, and a safety-detector unit is provided in the power supply which allows power to be supplied only if the switching means is actuated.
  • a lighting apparatus for discharge lamps wherein a switching means thereof has a movable unit of electrically-conductive material for connection two conductors to a safety-detector unit.
  • a lighting apparatus for discharge lamps wherein the socket has a movable unit accepting a discharge lamp which can rotate relative to a housing of the socket between a position at which the discharge lamp is inserted and a position at which the discharge lamp is fully secured in the socket, and a contact arm which forms connection with a shield placed over the outer circumference of the socket when the movable unit is turned to the position at which the discharge lamp is fully secured, and a safety-detector unit is provided in the power supply which allows power to be supplied only if the contact arm forms connection with the shield.
  • a socket for discharge lamps comprises a housing having a cavity for the reception of a discharge lamp, a first contact and a second contact arranged in such a manner that they face the cavity, the housing has a movable unit which engages mounting pins of the discharge lamp and which can rotate relative to the housing between a position at which the discharge lamp is inserted and a position at which the discharge lamp is fully secured in the socket, and a third contact is connected to a conductor other than conductors connected to the first and second contacts, the third contact is driven by rotation of the movable unit so as to connect with a shield placed over the outer circumference of the housing or with the second contact.
  • a socket for discharge lamps wherein the movable unit has a latch arm which latches the housing when the movable unit is in the position at which the discharge lamp is fully secured in the socket .
  • a socket for discharge lamps wherein in the discharge lamp socket a third contact and a fourth contact are provided in addition to the first contact and second contact, and the movable unit is of an electrically-conductive material, and, depending on its rotational position relative to the housing, it can short circuit the third and fourth contacts.
  • a lighting apparatus for discharging lamps comprising a socket for receiving a discharge lamp, a power supply for supplying electrical power to the socket, the socket including a housing having a cavity in which first and second electrical contacts are located for electrical connection to the discharge lamp wherein a movable unit is mounted in the housing and is movable relative to the housing between a first position at which the discharge lamp is inserted into the cavity and a second position at which the discharge lamp is fully secured in the socket whereby switching means is actuated when the movable unit is at the second position, and a safety-detector unit is provided in the power supply which actuates a power supply unit to supply power to the discharge lamp upon actuation of the switching means .
  • Figure 1 is a schematic diagram of a first embodiment of a discharge lamp lighting apparatus according to the present invention.
  • Figure 2 is a schematic diagram of a second embodiment of a discharge lamp lighting apparatus according to the present invention.
  • Figure 3 is an exploded perspective top view of a discharge lamp socket according to another embodiment of the present invention.
  • Figure 4 is an exploded perspective bottom view of a discharge lamp socket depicted in Figure 3.
  • Figure 5 is an exploded perspective bottom view from the back of the discharge lamp socket depicted in Figure 3.
  • Figure 6 is a cross-sectional view of the discharge lamp socket depicted in Figure 3.
  • Figure 7 is a perspective view of a shield flap of the discharge lamp socket depicted in Figure 3.
  • Figure 8 is a perspective bottom view from the front of another embodiment of the discharge lamp socket according to the present invention.
  • Figure 9 is an exploded perspective view from the rear of the discharge lamp socket shown in Figure 8.
  • Figure 10 is a perspective top view from the back of the discharge lamp socket shown in Figure 8 with the housing cover removed.
  • Figure 11 is the same perspective view as in Figure 10 showing short circuited third and fourth contacts.
  • Figure 12 is a perspective view of a movable unit used in the discharge lamp socket shown in Figure 8.
  • Figure 13 is a cross-sectional view taken along line 13-13 in Figure 12.
  • Figure 14 is a front view of a main housing used in the discharge lamp socket depicted in Figure 8 showing the first and second contacts.
  • Figure 15 is a cross-sectional view taken along line 15-15 in Figure 14.
  • Figure 16 is a cross-sectional view from the back of a further embodiment of the discharge lamp socket according to the present invention.
  • Figure 17 is a cross-sectional view from the back of yet another embodiment of the discharge lamp socket according to the present invention.
  • Figure 18 is a cross-sectional view of a conventional discharge lamp socket.
  • Figure 19 is a circuit diagram of high-voltage starting circuit and over-voltage protection circuit for the socket shown in Figure 18.
  • the lighting apparatus for discharge lamps comprises a discharge lamp 8, a discharge lamp socket 1 and a power supply 6 supplying electrical energy to the discharge lamp 8.
  • Power supply 6 is powered by a car battery ' (not shown).
  • Discharge lamp 8 includes a sealed discharge lamp tubular body 80 made of quartz glass filled with xenon, mercury vapor or other suitable gas and a mounting device 82 made of an insulating material.
  • Mounting device 82 has a large-diameter flange 84, a medium-diameter section 86 with mounting pins 90 arranged on its side surface and a small-diameter section 88.
  • a center terminal (not shown) is provided and a side terminal 94 is located on an outside surface of the small-diameter section 88 next to the medium-diameter section 86.
  • Socket 1 comprises an insulating housing 10 having a cavity 12 for the reception of the discharge lamp 8, first contact 14 and second contact 16 intended to be connected respectively to the center terminal and side terminal 94 of the discharge lamp 8.
  • a movable unit 18 of an insulating material is arranged inside the cavity 12 of the socket housing 10 and can rotate sliding along an inside circumference of cavity 12, and third sliding arm contact 20 which rotates together with the movable unit 18.
  • the circumference of the socket 1 is enclosed in a metal shield 22.
  • the first contact 14 of the socket 1 is connected to a first conductor 26 extending from one end of shielded cable 24, second contact 16 is connected to a second conductor 28 of cable 24, and the third contact 20 is connected to a third conductor 30 of cable 24.
  • Shielding sleeve 32 of the shielded cable 24 is connected to an inside wall of the opening 34 in the metal shield 22.
  • the other end of the shielded cable 24 is connected to the power supply 6.
  • the first conductor 26 and the second conductor 28 of the shielded cable 24 are connected to terminals 62, 64 respectively of the power supply unit 60 providing electrical energy to the discharge lamp 8.
  • the power supply unit 60 comprises an igntion circuit generating a high voltage (for example 28 kV) necessary to light the discharge lamp 8 and a ballast circuit delivering stabilized power (for example, 35 W) after the lamp is lit.
  • the third conductor 30 and the shielding sleeve 32 of the shielded cable 24 are connected to terminals 68, 70 of the safety-detector unit 66.
  • the shielding sleeve 32 is also connected to the metal box 72 shielding the power supply 6 through opening 74.
  • the metal box 72 is connected to ground 76 of the vehicle chassis (not shown) .
  • the safety-detector unit 66 and the power supply unit 60 are connected by a conductor 78. If terminals 68, 70 of the safety-detector unit 66 are short circuited, the safety-detector unit 66 generates a signal delivered via the conductor 78 which allows the power supply unit 60 to generate power to operate the discharge lamp.
  • This electric shock prevention system operates as follows.
  • the movable unit 18 located inside the socket 1 has slots 18b into which mounting pins 90 of the discharge lamp 8 are inserted. Therefore, when the discharge lamp 8 is inserted in the cavity 12 of the socket 1 and when the socket 1 is turned to a predetermined angle, the movable unit 18, due to the engagement of pins 90 in slots 18b, is rotated relative to the socket 1 from a position at which the discharge lamp is inserted to a position at which the discharge lamp is secured in the socket. Because of this rotation, the cam 18a located on one side of the movable unit 18 displaces the third contact 20 outward so that it makes electrical contact with an inside wall of the metal shield 22 as shown in Figure 1.
  • the electrical contact formed between the third contact 20 and the shield 22 constitute a switch means thereby forming a short circuit condition between terminals 68 and 70 of the safety-detector unit 66.
  • the safety- detector unit 66 therefore delivers a signal over the conductor 78 to the power supply unit 60 allowing the generation of high voltage thereby, thus providing electrical energy to the discharge lamp.
  • the cam 18a of the movable unit 18 does not displace the third contact 20 outward. If the third contact 20 is not displaced by the cam 18a, it does not form electrical contact with the shield 22. Therefore, the contacts 68 and 70 of the safety-detector unit 66 are not short circuited and no operating signal is sent to the power supply unit 60 resulting in zero voltage to the socket. No voltage is therefore applied to the first contact 14 and the second contact 16 of the socket 1, which eliminates the danger of electric shock to workers.
  • FIG. 2 is a schematic diagram showing a second embodiment of the lighting apparatus according to this invention for discharge lamps. The components of this embodiment corresponding to components of the first embodiment are marked with the same numbers having a prime symbol.
  • the socket 1' of this embodiment is different from the socket 1 of the first embodiment in the respect that if the discharge lamp 8 is missing or improperly inserted in the socket l 1 , the third contact 20' and the second contact 16' are not connected (the position shown by broken lines) , and when the discharge lamp 8 is properly secured in the socket 1', the third contact 20' is displaced inward by the cam 18a' of the movable unit 18', thus forming electrical connection with the second contact 16'.
  • the third contact 20' and the second contact 16 f thereby constitute a switching means.
  • the power supply 6' of this embodiment is different from the power supply 6 of the first embodiment by the fact that one terminal 64 of the power supply unit 60 is connected to one terminal 68 of the safety-detector unit 66 and the third conductor 30 of the shielded cable 24 is connected to the other terminal 70 of the safety-detector unit 66.
  • FIGs 3-7 depict a different embodiment of the discharge lamp socket according to this invention.
  • Insulating housing 10" of the socket 1" shown in Figures 3 through 6 comprises housing body 11 receiving the discharge lamp (not shown) and a housing cover 54 retaining conductors 26, 28 and 30 as shown in Figure 6.
  • the first contact 14 located at the center of the socket 1" is aligned with the axis of the housing body 11.
  • the first contact 14 has several contact leaves 14a, which receive and make electrical contact with the central terminal of the discharge lamp 8.
  • a connecting clip 14b is provided for connection to the first conductor 26.
  • the contact leaves 14a are surrounded by a wall 40 of the housing body 11 and by a seal 42, which prevents discharge.
  • the outer second contact 16 is arranged between the outer wall 36 of the housing body 11 and its inside wall 44. Two contact tabs 16a at the free ends of the second contact 16 extend inside the socket through two cutouts 44a in the inside wall 44.
  • the movable unit 18" of the socket 1" is made from metal sheet material by stamping and forming. It can rotate relative to the housing body 11 around the axis thereof along the inner surface of the outer wall 36 of the housing body 11.
  • the movable unit 18" has two slots 18b which can be aligned with two slots 38 in the outer wall 36. Their purpose is the same as that of the slots 38, that is to receive the mounting pins 90 of the discharge lamp 8.
  • the differences between the movable unit 18" and the movable units 18 and 18' shown in Figures 1 and 2 are that it is made of a metal, that it has a latch arm 18c protruding through opening 46 in the outer wall 36 of the housing body 11, and that the third conductor 30 is terminated thereto at the rear end of the housing body 11. Therefore, by rotating the movable unit 18" relative to the housing body 11, the latch arm 18c can be moved from the position at which the discharge lamp is inserted to the position at which the discharge lamp is fully secured.
  • the front end of the latch arm 18c engages against the inner wall of the opening 46 of the housing body 11 (as shown by broken lines in Figures 16 and 17) , thus preventing rotation of the movable unit 18" in the opposite direction.
  • the latch arm 18c can be released by pressing it inward and disengaging it from the opening 46, after which the housing body 11 can be rotated in the opposite direction.
  • the latch arm 18c protruding through the opening 46 performs the function of a switching means when it comes in contact with a lug 22a extending inward of the metal shield 22".
  • housing cover 54 of the socket 1" has multiple ribs 56 which together with multiple ribs 48 of the housing body 11 retain conductor 26.
  • these ribs 48, 56 provide stress relief for the conductor 26. Since conductors 26, 28 and 30 are brought out of the housing cover 54 in a forward direction, as explained below, only a small opening 22c is required in the shield 22", thus providing for a better shielding. Since as can be seen from Figures 3 and 4 the upper half of the housing body 11 and the housing cover 54 form a smooth surface, the shield 22" can be easily placed over the housing 10".
  • the shield 22" is metal and it is shaped so that it covers practically the entire surface of the socket 1" except for the opening for the housing and the outlet for the conductors 26, 28 and 30.
  • the shield 22" has on its inside surface lug 22a protruding inside which forms electrical contact with the latch arm 18c of the movable unit 18".
  • an outward extending protrusion 22b is on the shield 22" between the housing opening and the lug 22a to avoid contact between the latch arm 18c of the movable unit 18" and the shield. Due to this outward extending protrusion 22b, the electrical contact with the latch arm 18c can be obtained only if the shield is properly placed over the housing.
  • Flap 23 has at its one end a spring-loaded contact 23a to provide electrical connection with the reflector 3 (see Figure 1), and at the other end, it has a connector 23b providing connection for the shielding sleeve 32 of the shielded cable 24 by compression or by some other method.
  • wings 23d and 23e are provided which fit over opposing edges of the cutout 22c.
  • the flap 23 has basically the same configuration as the cutout 22c, thus preventing magnetic interference from leaking through the cutout 22c. Due to the fact that the cross section of the shield 22" is of the same small diameter as the housing cover 54 and the cutout 22c for the cable 24 is made only in the lower portion of the shield, it can be placed over the socket 1" only when it is correctly aligned. Therefore, no high voltage is applied to the first and second contacts 14 and 16. It is desirable that the shield 22" has at its front end spring-loaded contacts 22d as shown in Figure 4 to provide for electrical connection with the reflector 3.
  • the electric shock protection apparatus is basically the same as in the embodiment shown in Figure 1. Namely, the first conductor 26 connected to the first contact 14 of the socket 1" is connected to one terminal 62
  • Power is delivered to the discharge lamp 8 according to the following procedure.
  • the discharge lamp 8 is mounted in the reflector 3, 3' of the motor vehicle.
  • the socket 1" is connected to the base of the discharge lamp 8 by rotating the socket 1" clockwise to a predetermined angle.
  • the movable unit 18" and the mounting pins 90 of the discharge lamp 8 do not move relative to the reflector 3, 3' and the discharge lamp 8, but they are rotated relative to the housing body 11 and the cover 54.
  • the mounting pins 90 of the discharge lamp 8 are inserted in the slots 38 of the man housing body 11 and the latch arm 18c of the movable unit 18" is engaged with the opening 46 of the housing body 11, thus preventing rotation of the movable unit 18" relative to the housing body 11 in the opposite direction.
  • the shield 22" is mounted over the socket 1" from the back side so that the inward-extending lug 22a of the shield 22" is disposed into the opening 46 of the housing body 11, thus making electrical connection with the latch arm 18c of the movable unit 18".
  • terminals 68 and 70 of the safety-detector unit 66 become short circuited for the first time, and the power supply unit 60 is enabled to deliver electrical energy to the discharge lamp.
  • FIGS 8-15 depict another embodiment of discharge lamp socket 1''' according to this invention.
  • the embodiment of the lamp socket l' 1 ' depicted in Figures 8 and 9 is similar to the embodiment shown in Figures 3 through 6 and comprises insulating housing 10' '' including housing body ll' 1 ' and housing cover 54''', first and second contacts 14 and 16, and a movable unit
  • the housing body 11''' is basically similar to the housing body 11 shown in Figures 3 through 6 with respect to the parts concerned with the insertion of the discharge lamp 8 (see Figure 1 or 2) , except that, for the purposes of reinforcement of slots 38, they have bridges 39 at their openings, and a downward extension 41 is provided under the discharge lamp receptacle to cover conductors 26, 28, 30 and 31.
  • the housing cover 54''' also has an extension 59 covering conductors 26, 28, 30 and 31.
  • a metal shield clip 92 is provided around extensions 41 and 59.
  • the shielding sleeve 32 of the shielded cable 24 (see Figure 9) is secured between extensions 41, 59 and the shield clip 92.
  • Press-in sections 94c, 96c located between contact members 94a, 96a and conductor- connecting sections 94b, 96b have shoulders 94d, 96d supporting the housing cover 54'''. Since the contact members 94a, 96a have practically no flexibility, the harness comprising conductors 30, 31 and contacts 94, 96 together with the power supply 6 (see Figures 1 and 2) can withstand rather high temperatures (up to 200°C) without detrimental effect on the contact properties of the contacts 94, 96. When third and fourth contacts 94, 96 are mounted in the receiving slots 51, 53 of the housing body 11''', the force of the mounting tool (not shown) is applied to the shoulders 94d, 96d. This prevents the contact members 94a, 96a from deformation during the assembly.
  • the movable unit 18 ' ' ' shown in Figures 12 through 16 has slots 18b receiving the mounting pins 90 of the discharge lamp (see Figures 1 or 2) and the latch arm 18c which fits into two slots 45, 47 (see Figure 14) of the housing body 11'''.
  • the movable unit 18' '' also has spring-loaded arms 18e, 18f, the purpose of which is to make electrical connection with third and fourth contacts 94, 96 respectively (see Figure 11), and stop tabs 18g, 18h which engage against stop surface 49 of the housing body 11''' (see Figure 15).
  • the movable unit 18' '' is inserted in the housing body 11' '' from the back side (the right side in Figure 15) until the stop tabs 18g, 18h engage against the surface 49.
  • the spring-loaded arms 18e, 18f have arcuate tabs 18i, 18j at their edges.
  • Contact sections 94a, 96a of the third and fourth contacts 94, 96 are rounded to make electrical connection with spring-loaded arms 18e, 18f of the movable unit
  • Two slots 45, 47 of the housing body 11''' correspond to the positions in which the discharge lamp is only inserted and fully secured, respectively. In the position when the discharge lamp is not inserted, the latch arm 18c of the movable unit 18''' snaps into the slot 45.
  • the third conductor 30 of the shielded cable 24 can be connected to the third contact 20'''' which forms electrical connection with the movable unit 18' 1 ' 1 , as shown in Figure 16, rather than using a separate fourth conductor.
  • the third contact 20' ' ' ' has a tab (not shown) extending perpendicularly to the plane of the drawing which is secured in the housing, thus providing appropriate contact pressure between the third contact 20' ' ' ' and the movable unit 18 ' ' ' ' , as well as securing contact between the latch arm 18c and the shield (not shown) .
  • the safety-detector unit and the safety-detection circuit have the fewest number of components, thus minimizing the cost of the equipment.
  • the safety-detector unit 66 deliveres the signal to the power supply unit 60 allowing it to deliver electrical energy only when the terminals 68, 70 are short circuited; however, it is possible to use an arrangement in which the signal to the power supply unit 60 will be generated when the terminals 68, 70 are open.
  • the socket according to the above embodiment it is necessary to implement reverse switching, namely, it is necessary to arrange the switching means so that it opens the circuit when the discharge lamp is properly secured in the socket.
  • the lighting apparatus for discharge lamps according to this invention can be also implemented in the form of the following embodiment.
  • the lighting apparatus for discharge lamps comprises a socket holding the discharge lamp and a power supply unit delivering electrical energy to the socket wherein a switching means is provided in the socket operated by a movable unit accommodating the discharge lamp which can rotate relative to a housing of the socket between a position at which the discharge lamp is inserted and a position at which the discharge lamp is fully secured in the socket, switching means is actuated when the discharge lamp is rotated to the position of its fully secured engagement, the switching means is comprised of any one of two contacts connected to two terminals of the discharge lamp and a third contact, and a safety-detector unit allowing delivery of electrical energy from the power supply unit only if the switching means is actuated.
  • the socket for discharge lamps can be also implemented in the form of the following embodiments.
  • the socket for discharge lamps comprises a housing having a cavity for the reception of a discharge lamp, a contact centrally disposed in the cavity and an outer contact wherein a movable unit of conductive material is arranged in the housing cavity which can rotate relative to the housing of the socket between a position at which the discharge lamp is inserted and a position at which the discharge lamp is fully secured in the socket and which can engage mounting pins of the discharge lamp located on the sides of its base, and a latch arm is provided on the movable unit which forms electrical contact with a shield mounted on the outer surface of the housing and extends through an opening in an outside wall of the housing when the discharge lamp is in the fully-secured position.
  • the conductive latch arm is locked in the housing opening when the discharge lamp is in the fully- secured position forming electrical contact with the shield, thereby making it possible, with only few components, not only to latch the discharge lamp in the fully-secured position but also to generate a signal when the discharge lamp and the shield are in the fully-secured position.
  • An advantage of the lighting apparatus for discharge lamps according to the present invention is that it makes it possible to prevent electric shock during installation or replacement of discharge lamps without using lamps of special design.
  • Another advantage of the lighting apparatus for discharge lamps according to the present invention is that, due to considerably fewer contacts in the safety-detection circuit formed by the safety-detector unit, the presence two conductors and the movable unit, reliability of the connections in the safety-detection circuit is much higher.
  • a further advantage of the lighting apparatus for discharge lamps according to the present invention is that no electrical power is supplied to the socket unless the discharge lamp or the shield are properly installed, resulting in greater safety and absence of the effect of magnetic interference on other equipment .
  • An additional advantage of the discharge lamp socket according to the present invention is that it makes it possible to reliably prevent the discharge lamp from leaving the socket while minimizing the number of socket components.

Abstract

A lighting apparatus and a socket for discharge lamps is provided for blocking power supply to the socket if the discharge lamp or the shield are not properly installed making it possible to use conventional discharge lamps. Socket (1) has first and second contacts (14, 16) connected to two terminals of a discharge lamp (8) and a third contact (20) which is connected to a safety-detector unit (66) by means of the shielded cable (24). The third contact (20) can be connected to the shield (22) when it is pressed by rotating a movable unit (18) together with the discharge lamp relative to a socket housing (10). Two terminals (68, 70) of the safety-detector unit are short circuited only when the discharge lamp (8) and the shield (22) are properly installed, thus allowing supply of electrical energy from the power-supply unit (60).

Description

LIGHTING APPARATUS FOR DISCHARGE LAMPS AND DISCHARGE LAMP SOCKET USED THEREIN
This invention relates to sockets for discharge lamps for motor vehicle headlights and lighting apparatus for such lamps. Compared to conventional incandescent lamps or halogen lamps, gas discharge lamps are distinguished by high brightness, lower power consumption, small size and long life. Because of these advantages, it is expected that these lamps will eventually replace halogen and incandescent lamps currently used in vehicle head lights. Despite the long life of the discharge lamps, some car owners, especially in Western Europe, find it desirable to replace discharge lamps on their own. Since a high voltage is applied to the discharge lamp through an igniter, it is desirable to provide an apparatus protecting the car owners or repairmen replacing discharge lamps from electric shock.
An example of a socket for discharge lamps having means for protection of workers replacing a discharge lamp from electric shock is shown in Figure 18 disclosed in Japanese Patent Application No. 6-17173. The discharge lamp unit 100 comprises a discharge lamp 102 and a terminal unit 104. The terminal unit 104 has three post terminals 106, 108, 110. Two terminals 108, 110 are regular terminals for power supply. Socket 120 for the discharge lamp has receptacle terminals 122, 124, 126 mating with the three post terminals 106, 108 and 110. As shown in Figure 19, two terminals 106, 108 of the discharge lamp unit 100 are connected to a high-voltage starting circuit 130 of discharge lamp 102, and the common terminal 110 is connected to an overvoltage protection circuit 132. The overvoltage-protection circuit 132 detects whether the discharge lamp unit 100 is connected to the high-voltage starting circuit 130 of discharge lamp 102 via the terminal 126 or not. This circuit blocks the generation of high voltage by the high-voltage starting circuit 130 of discharge lamp 102 if the discharge lamp unit 100 is not inserted in the discharge lamp socket 120, thus preventing the worker from electric shock. The socket 120 for discharge lamps described in the above
Japanese Application is designed to accommodate special discharge lamps having three terminals. Because of this, they cannot be used with present standard two-terminal discharge lamps, and discharge lamps and sockets having three terminals did not receive wide acceptance in the market.
In addition, the discharge lamp must be operated by high voltage and its lighting apparatus must be thoroughly shielded because they generate magnetic interference. However, no measures against magnetic interference are offered in the socket and the surrounding apparatus described in the above Japanese
Application. A faulty shield around the socket and surrounding apparatus can result in dangerously high voltage applied to unrelated equipment.
Therefore, the first purpose of this invention is to offer a lighting apparatus and a socket for discharge lamps which would make it possible to prevent electric shock at the time of replacement of standard discharge lamps having two terminals by preventing the generation of high voltage.
The other purpose of this invention is to offer a socket for discharge lamps and a lighting apparatus using such a socket which prevents generation of high voltage in the event the shield is faulty.
A lighting apparatus for discharge lamps comprises a socket receiving a discharge lamp and a power supply providing power to the socket wherein the socket has a switching means comprised of a movable unit accepting the discharge lamp which can rotate relative to a housing of the socket between a position at which the discharge lamp is inserted and a position at which the discharge lamp is fully secured in the socket, which switching means is actuated when the movable unit is turned to the position at which the discharge lamp is fully secured in the socket, and a safety-detector unit is provided in the power supply which allows power to be supplied only if the switching means is actuated.
A lighting apparatus for discharge lamps wherein a switching means thereof has a movable unit of electrically-conductive material for connection two conductors to a safety-detector unit. A lighting apparatus for discharge lamps wherein the socket has a movable unit accepting a discharge lamp which can rotate relative to a housing of the socket between a position at which the discharge lamp is inserted and a position at which the discharge lamp is fully secured in the socket, and a contact arm which forms connection with a shield placed over the outer circumference of the socket when the movable unit is turned to the position at which the discharge lamp is fully secured, and a safety-detector unit is provided in the power supply which allows power to be supplied only if the contact arm forms connection with the shield.
A socket for discharge lamps comprises a housing having a cavity for the reception of a discharge lamp, a first contact and a second contact arranged in such a manner that they face the cavity, the housing has a movable unit which engages mounting pins of the discharge lamp and which can rotate relative to the housing between a position at which the discharge lamp is inserted and a position at which the discharge lamp is fully secured in the socket, and a third contact is connected to a conductor other than conductors connected to the first and second contacts, the third contact is driven by rotation of the movable unit so as to connect with a shield placed over the outer circumference of the housing or with the second contact.
A socket for discharge lamps wherein the movable unit has a latch arm which latches the housing when the movable unit is in the position at which the discharge lamp is fully secured in the socket .
A socket for discharge lamps wherein in the discharge lamp socket a third contact and a fourth contact are provided in addition to the first contact and second contact, and the movable unit is of an electrically-conductive material, and, depending on its rotational position relative to the housing, it can short circuit the third and fourth contacts.
A lighting apparatus for discharging lamps comprising a socket for receiving a discharge lamp, a power supply for supplying electrical power to the socket, the socket including a housing having a cavity in which first and second electrical contacts are located for electrical connection to the discharge lamp wherein a movable unit is mounted in the housing and is movable relative to the housing between a first position at which the discharge lamp is inserted into the cavity and a second position at which the discharge lamp is fully secured in the socket whereby switching means is actuated when the movable unit is at the second position, and a safety-detector unit is provided in the power supply which actuates a power supply unit to supply power to the discharge lamp upon actuation of the switching means .
Embodiments of the invention will not be described by way of example with reference to the accompanying drawings in which:
Figure 1 is a schematic diagram of a first embodiment of a discharge lamp lighting apparatus according to the present invention. Figure 2 is a schematic diagram of a second embodiment of a discharge lamp lighting apparatus according to the present invention.
Figure 3 is an exploded perspective top view of a discharge lamp socket according to another embodiment of the present invention.
Figure 4 is an exploded perspective bottom view of a discharge lamp socket depicted in Figure 3.
Figure 5 is an exploded perspective bottom view from the back of the discharge lamp socket depicted in Figure 3.
Figure 6 is a cross-sectional view of the discharge lamp socket depicted in Figure 3.
Figure 7 is a perspective view of a shield flap of the discharge lamp socket depicted in Figure 3. Figure 8 is a perspective bottom view from the front of another embodiment of the discharge lamp socket according to the present invention.
Figure 9 is an exploded perspective view from the rear of the discharge lamp socket shown in Figure 8. Figure 10 is a perspective top view from the back of the discharge lamp socket shown in Figure 8 with the housing cover removed.
Figure 11 is the same perspective view as in Figure 10 showing short circuited third and fourth contacts. Figure 12 is a perspective view of a movable unit used in the discharge lamp socket shown in Figure 8.
Figure 13 is a cross-sectional view taken along line 13-13 in Figure 12.
Figure 14 is a front view of a main housing used in the discharge lamp socket depicted in Figure 8 showing the first and second contacts. Figure 15 is a cross-sectional view taken along line 15-15 in Figure 14.
Figure 16 is a cross-sectional view from the back of a further embodiment of the discharge lamp socket according to the present invention.
Figure 17 is a cross-sectional view from the back of yet another embodiment of the discharge lamp socket according to the present invention.
Figure 18 is a cross-sectional view of a conventional discharge lamp socket.
Figure 19 is a circuit diagram of high-voltage starting circuit and over-voltage protection circuit for the socket shown in Figure 18.
The lighting apparatus for discharge lamps comprises a discharge lamp 8, a discharge lamp socket 1 and a power supply 6 supplying electrical energy to the discharge lamp 8. Power supply 6 is powered by a car battery '(not shown). Discharge lamp 8 includes a sealed discharge lamp tubular body 80 made of quartz glass filled with xenon, mercury vapor or other suitable gas and a mounting device 82 made of an insulating material. Mounting device 82 has a large-diameter flange 84, a medium-diameter section 86 with mounting pins 90 arranged on its side surface and a small-diameter section 88. At the bottom surface of the small- diameter section 88 (the right end in Figure 1) , a center terminal (not shown) is provided and a side terminal 94 is located on an outside surface of the small-diameter section 88 next to the medium-diameter section 86.
Socket 1 comprises an insulating housing 10 having a cavity 12 for the reception of the discharge lamp 8, first contact 14 and second contact 16 intended to be connected respectively to the center terminal and side terminal 94 of the discharge lamp 8. A movable unit 18 of an insulating material is arranged inside the cavity 12 of the socket housing 10 and can rotate sliding along an inside circumference of cavity 12, and third sliding arm contact 20 which rotates together with the movable unit 18. The circumference of the socket 1 is enclosed in a metal shield 22. The first contact 14 of the socket 1 is connected to a first conductor 26 extending from one end of shielded cable 24, second contact 16 is connected to a second conductor 28 of cable 24, and the third contact 20 is connected to a third conductor 30 of cable 24. For the connection of contacts to their respective conductors, any method known in the art can be used, such as soldering, welding, crimping, pressure contact, etc. Shielding sleeve 32 of the shielded cable 24 is connected to an inside wall of the opening 34 in the metal shield 22. The other end of the shielded cable 24 is connected to the power supply 6. Namely, the first conductor 26 and the second conductor 28 of the shielded cable 24 are connected to terminals 62, 64 respectively of the power supply unit 60 providing electrical energy to the discharge lamp 8. It is not shown in the drawing, but the power supply unit 60 comprises an igntion circuit generating a high voltage (for example 28 kV) necessary to light the discharge lamp 8 and a ballast circuit delivering stabilized power (for example, 35 W) after the lamp is lit. The third conductor 30 and the shielding sleeve 32 of the shielded cable 24 are connected to terminals 68, 70 of the safety-detector unit 66. The shielding sleeve 32 is also connected to the metal box 72 shielding the power supply 6 through opening 74. The metal box 72 is connected to ground 76 of the vehicle chassis (not shown) . The safety-detector unit 66 and the power supply unit 60 are connected by a conductor 78. If terminals 68, 70 of the safety-detector unit 66 are short circuited, the safety-detector unit 66 generates a signal delivered via the conductor 78 which allows the power supply unit 60 to generate power to operate the discharge lamp.
This electric shock prevention system operates as follows. The movable unit 18 located inside the socket 1 has slots 18b into which mounting pins 90 of the discharge lamp 8 are inserted. Therefore, when the discharge lamp 8 is inserted in the cavity 12 of the socket 1 and when the socket 1 is turned to a predetermined angle, the movable unit 18, due to the engagement of pins 90 in slots 18b, is rotated relative to the socket 1 from a position at which the discharge lamp is inserted to a position at which the discharge lamp is secured in the socket. Because of this rotation, the cam 18a located on one side of the movable unit 18 displaces the third contact 20 outward so that it makes electrical contact with an inside wall of the metal shield 22 as shown in Figure 1. Therefore, when the discharge lamp 8 is properly secured in the socket 1 and when the shield 22 is properly positioned in the socket 1, the electrical contact formed between the third contact 20 and the shield 22 constitute a switch means thereby forming a short circuit condition between terminals 68 and 70 of the safety-detector unit 66. The safety- detector unit 66 therefore delivers a signal over the conductor 78 to the power supply unit 60 allowing the generation of high voltage thereby, thus providing electrical energy to the discharge lamp.
In the event that the discharge lamp 8 is not properly secured in the socket 1 (including the case when the discharge lamp 8 is not inserted in the socket) , the cam 18a of the movable unit 18 does not displace the third contact 20 outward. If the third contact 20 is not displaced by the cam 18a, it does not form electrical contact with the shield 22. Therefore, the contacts 68 and 70 of the safety-detector unit 66 are not short circuited and no operating signal is sent to the power supply unit 60 resulting in zero voltage to the socket. No voltage is therefore applied to the first contact 14 and the second contact 16 of the socket 1, which eliminates the danger of electric shock to workers.
If the shield 22 is not properly positioned over the socket (including the case of a missing shield) , there will be no electrical contact between the third contact 20 and the shield 22 even if the third contact 20 is displaced by the cam 18a. As a result, similar to the case when the discharge lamp 8 is not properly secured in the socket 1, no power is delivered from the power supply unit 60, and there is no danger of electric shock for workers. When the shield 22 is properly positioned over the socket 1 and the third contact 20 forms electrical connection with the inside wall of the shield 22, the spring-loaded contact 22d located at the front end of the shield 22 makes electrical contact with conductive reflector 3, thereby forming a shield extending from the power supply 6 through the shielded cable 24, the socket 1 and the reflector 3 which prevents magnetic interference from affecting other equipment of the motor vehicle. Figure 2 is a schematic diagram showing a second embodiment of the lighting apparatus according to this invention for discharge lamps. The components of this embodiment corresponding to components of the first embodiment are marked with the same numbers having a prime symbol. The socket 1' of this embodiment is different from the socket 1 of the first embodiment in the respect that if the discharge lamp 8 is missing or improperly inserted in the socket l1, the third contact 20' and the second contact 16' are not connected (the position shown by broken lines) , and when the discharge lamp 8 is properly secured in the socket 1', the third contact 20' is displaced inward by the cam 18a' of the movable unit 18', thus forming electrical connection with the second contact 16'. The third contact 20' and the second contact 16 f thereby constitute a switching means. The power supply 6' of this embodiment is different from the power supply 6 of the first embodiment by the fact that one terminal 64 of the power supply unit 60 is connected to one terminal 68 of the safety-detector unit 66 and the third conductor 30 of the shielded cable 24 is connected to the other terminal 70 of the safety-detector unit 66.
Therefore, when the discharge lamp 8 is properly secured in the socket 1', the second contact 16' and the third contact 20' are connected with each other, thereby short-circuiting the terminals 68 and 70 of the safety detector unit 66. Therefore, a signal allowing delivery of high voltage power from the power supply unit 60 is transmitted by the conductor 78, thus causing the power supply unit to be in the operating mode. Conversely, if the discharge lamp 8 is not inserted in the socket 1 ' or if it is improperly mounted therein, the third contact 20' and the second contact 16' are not connected, thus terminals 68 and 78 of the safety detector unit 66 are likewise not connected. Therefore, no signal allowing the power supply unit 60 to deliver high voltage power is generated, and workers can safely handle the socket without danger of electric shock. Figures 3-7 depict a different embodiment of the discharge lamp socket according to this invention. Insulating housing 10" of the socket 1" shown in Figures 3 through 6 comprises housing body 11 receiving the discharge lamp (not shown) and a housing cover 54 retaining conductors 26, 28 and 30 as shown in Figure 6. In an outside wall 36 of the housing body 11, four J-shaped slots 38 are provided, which are open to the side for insertion of the discharge lamp in the socket and which are arranged at equal distances from each other. These slots 38 are intended for the reception of mounting pins 90 (see Figures 1 or 2) of the discharge lamp 8 constituting a bayonet-type connection of the lamp base. The first contact 14 located at the center of the socket 1" is aligned with the axis of the housing body 11. As can be seen from Figure 6, the first contact 14 has several contact leaves 14a, which receive and make electrical contact with the central terminal of the discharge lamp 8. At the opposite end of the first contact 14, a connecting clip 14b is provided for connection to the first conductor 26. The contact leaves 14a are surrounded by a wall 40 of the housing body 11 and by a seal 42, which prevents discharge. The outer second contact 16 is arranged between the outer wall 36 of the housing body 11 and its inside wall 44. Two contact tabs 16a at the free ends of the second contact 16 extend inside the socket through two cutouts 44a in the inside wall 44. These two tabs 16a form electrical connection with the outside terminal 94 (see Figures 1 and 2) of the discharge lamp 8. The movable unit 18" of the socket 1" is made from metal sheet material by stamping and forming. It can rotate relative to the housing body 11 around the axis thereof along the inner surface of the outer wall 36 of the housing body 11. In addition, the movable unit 18" has two slots 18b which can be aligned with two slots 38 in the outer wall 36. Their purpose is the same as that of the slots 38, that is to receive the mounting pins 90 of the discharge lamp 8. The differences between the movable unit 18" and the movable units 18 and 18' shown in Figures 1 and 2 are that it is made of a metal, that it has a latch arm 18c protruding through opening 46 in the outer wall 36 of the housing body 11, and that the third conductor 30 is terminated thereto at the rear end of the housing body 11. Therefore, by rotating the movable unit 18" relative to the housing body 11, the latch arm 18c can be moved from the position at which the discharge lamp is inserted to the position at which the discharge lamp is fully secured. In this position, the front end of the latch arm 18c engages against the inner wall of the opening 46 of the housing body 11 (as shown by broken lines in Figures 16 and 17) , thus preventing rotation of the movable unit 18" in the opposite direction. This eliminates the need of another latch resulting in reduction of the number of parts. The latch arm 18c can be released by pressing it inward and disengaging it from the opening 46, after which the housing body 11 can be rotated in the opposite direction. Moreover, since the movable unit 18" is connected to the third conductor 30, the latch arm 18c protruding through the opening 46 performs the function of a switching means when it comes in contact with a lug 22a extending inward of the metal shield 22". Therefore, the latch arm 18c performs the same function as the third contact depicted in Figure 1, thus making it possible to reduce the number of parts. As can be seen from Figure 6, housing cover 54 of the socket 1" has multiple ribs 56 which together with multiple ribs 48 of the housing body 11 retain conductor 26. When the housing cover 54 is secured on the housing body 11 by means of slot 58 of the housing cover 54 receiving projection 50 of the housing body 11, these ribs 48, 56 provide stress relief for the conductor 26. Since conductors 26, 28 and 30 are brought out of the housing cover 54 in a forward direction, as explained below, only a small opening 22c is required in the shield 22", thus providing for a better shielding. Since as can be seen from Figures 3 and 4 the upper half of the housing body 11 and the housing cover 54 form a smooth surface, the shield 22" can be easily placed over the housing 10".
As can be seen from Figures 3 through 5, the shield 22" is metal and it is shaped so that it covers practically the entire surface of the socket 1" except for the opening for the housing and the outlet for the conductors 26, 28 and 30. As noted above, the shield 22" has on its inside surface lug 22a protruding inside which forms electrical contact with the latch arm 18c of the movable unit 18". In addition, an outward extending protrusion 22b is on the shield 22" between the housing opening and the lug 22a to avoid contact between the latch arm 18c of the movable unit 18" and the shield. Due to this outward extending protrusion 22b, the electrical contact with the latch arm 18c can be obtained only if the shield is properly placed over the housing. Since the conductors 26, 28 and 30 extend forward, the cutout 22c is open toward the housing opening. In order to prevent magnetic interference from leaking from the socket 1" through the cutout 22c, it is desirable to provide a shield flap 23 as a separate metal piece shown in Figure 7 which covers the cutout 22c. Flap 23 has at its one end a spring-loaded contact 23a to provide electrical connection with the reflector 3 (see Figure 1), and at the other end, it has a connector 23b providing connection for the shielding sleeve 32 of the shielded cable 24 by compression or by some other method. On the right and left edges of the middle section 23c of the flap 23, wings 23d and 23e are provided which fit over opposing edges of the cutout 22c. The flap 23 has basically the same configuration as the cutout 22c, thus preventing magnetic interference from leaking through the cutout 22c. Due to the fact that the cross section of the shield 22" is of the same small diameter as the housing cover 54 and the cutout 22c for the cable 24 is made only in the lower portion of the shield, it can be placed over the socket 1" only when it is correctly aligned. Therefore, no high voltage is applied to the first and second contacts 14 and 16. It is desirable that the shield 22" has at its front end spring-loaded contacts 22d as shown in Figure 4 to provide for electrical connection with the reflector 3.
The electric shock protection apparatus according to this invention is basically the same as in the embodiment shown in Figure 1. Namely, the first conductor 26 connected to the first contact 14 of the socket 1" is connected to one terminal 62
(Figure 1) of the power supply unit 60, and the second conductor 28 connected to the second contact 16 is connected to the other terminal 64 (Figure 1) of the power supply unit 60. The third conductor 30 connected to the movable unit 18 instead of the third contact is connected to one terminal 68 of the safety- detector unit 66, and the shielding sleeve 32 of the shielded cable 24 connected to the shield 22" via the flap 23 is connected to the other terminal 70 of the safety-detector unit 66. Therefore, unless the shield 22" is properly set over the socket 1", terminals 68 and 70 of the safety-detector unit 66 remain disconnected and no high voltage power is supplied to the first and second contacts 14 and 16 of the socket 1", thus safeguarding workers from electric shock.
Power is delivered to the discharge lamp 8 according to the following procedure. First, the discharge lamp 8 is mounted in the reflector 3, 3' of the motor vehicle. Then the socket 1" is connected to the base of the discharge lamp 8 by rotating the socket 1" clockwise to a predetermined angle. During this rotation, the movable unit 18" and the mounting pins 90 of the discharge lamp 8 do not move relative to the reflector 3, 3' and the discharge lamp 8, but they are rotated relative to the housing body 11 and the cover 54. Therefore, the mounting pins 90 of the discharge lamp 8 are inserted in the slots 38 of the man housing body 11 and the latch arm 18c of the movable unit 18" is engaged with the opening 46 of the housing body 11, thus preventing rotation of the movable unit 18" relative to the housing body 11 in the opposite direction. After that, the shield 22" is mounted over the socket 1" from the back side so that the inward-extending lug 22a of the shield 22" is disposed into the opening 46 of the housing body 11, thus making electrical connection with the latch arm 18c of the movable unit 18". At this time, terminals 68 and 70 of the safety-detector unit 66 become short circuited for the first time, and the power supply unit 60 is enabled to deliver electrical energy to the discharge lamp. Figures 8-15 depict another embodiment of discharge lamp socket 1''' according to this invention. The embodiment of the lamp socket l'1' depicted in Figures 8 and 9 is similar to the embodiment shown in Figures 3 through 6 and comprises insulating housing 10' '' including housing body ll'1' and housing cover 54''', first and second contacts 14 and 16, and a movable unit
18''' of a conductive metal. The housing body 11''' is basically similar to the housing body 11 shown in Figures 3 through 6 with respect to the parts concerned with the insertion of the discharge lamp 8 (see Figure 1 or 2) , except that, for the purposes of reinforcement of slots 38, they have bridges 39 at their openings, and a downward extension 41 is provided under the discharge lamp receptacle to cover conductors 26, 28, 30 and 31. The housing cover 54''' also has an extension 59 covering conductors 26, 28, 30 and 31. A metal shield clip 92 is provided around extensions 41 and 59. The shielding sleeve 32 of the shielded cable 24 (see Figure 9) is secured between extensions 41, 59 and the shield clip 92.
As can be seen in Figures 10 and 11, ends of conductors 30, 31, whose other ends are connected to terminals 68, 70 of the safety-detector unit 66 (see Figure 1), are connected respectively to the third and fourth contacts 94 and 96. As shown in Figure 11, in the position when the discharge lamp is fully secured, the third and fourth contacts 94 and 96 are short circuited by the movable unit 18'''. Since the third and fourth contacts 94 and 96 are of the same configuration, they can be easily manufactured using the same equipment. Contacts 94, 96 have small-diameter semicircular contact members 94a, 96a and conductor-connecting sections 94b, 96b intended for the connection of conductors 30, 31 by crimping. Press-in sections 94c, 96c located between contact members 94a, 96a and conductor- connecting sections 94b, 96b have shoulders 94d, 96d supporting the housing cover 54'''. Since the contact members 94a, 96a have practically no flexibility, the harness comprising conductors 30, 31 and contacts 94, 96 together with the power supply 6 (see Figures 1 and 2) can withstand rather high temperatures (up to 200°C) without detrimental effect on the contact properties of the contacts 94, 96. When third and fourth contacts 94, 96 are mounted in the receiving slots 51, 53 of the housing body 11''', the force of the mounting tool (not shown) is applied to the shoulders 94d, 96d. This prevents the contact members 94a, 96a from deformation during the assembly.
The movable unit 18 ' ' ' shown in Figures 12 through 16 has slots 18b receiving the mounting pins 90 of the discharge lamp (see Figures 1 or 2) and the latch arm 18c which fits into two slots 45, 47 (see Figure 14) of the housing body 11'''. In addition, the movable unit 18' '' also has spring-loaded arms 18e, 18f, the purpose of which is to make electrical connection with third and fourth contacts 94, 96 respectively (see Figure 11), and stop tabs 18g, 18h which engage against stop surface 49 of the housing body 11''' (see Figure 15). The movable unit 18' '' is inserted in the housing body 11' '' from the back side (the right side in Figure 15) until the stop tabs 18g, 18h engage against the surface 49. The spring-loaded arms 18e, 18f have arcuate tabs 18i, 18j at their edges. Contact sections 94a, 96a of the third and fourth contacts 94, 96 are rounded to make electrical connection with spring-loaded arms 18e, 18f of the movable unit
18''' smooth. By adding the arcuate tabs 18i, 18j, it is possible to prevent collision of spring-loaded arms 18e, 18f with the contact sections 94a, 96a and make the electrical contact therebetween more reliable. Two slots 45, 47 of the housing body 11''' correspond to the positions in which the discharge lamp is only inserted and fully secured, respectively. In the position when the discharge lamp is not inserted, the latch arm 18c of the movable unit 18''' snaps into the slot 45. In this position, the discharge lamp 8 (Figure 1) is inserted in the socket 1''', and the mounting pins 90 are slid into the slots 18b of the movable unit 18 ' ' ' , after which the housing 10 ' ' ' is rotated in the direction shown by the arrow in Figure 9 and the latch arm 18c snaps into the slot 47 corresponding to the position of the fully secured discharge lamp. These slots 45, 47 and the latch arm 18c of the movable unit 18''' prevent accidental displacement of the movable unit 18''' which can be caused by vibration or other factors .
Since in this embodiment, in addition to the use of dedicated conductors 30, 31 directly connected to the safety- detector unit, the conductive movable unit is used as the switching means, it became possible to considerably reduce the number of contacts in the safety-detection circuit comprising the safety-detector unit, conductors 30, 31 and the movable unit 18''', thereby not only substantially improving the reliability of connections in the safety-detection circuit but also simplifying the design and the assembly process of the socket. Above, detailed explanations concerning the discharge lamp socket and the lighting apparatus for such a lamp according to the present invention have been given. However, this invention is not limited to the embodiments described above, but it also covers various modifications and changes which can be made as needed. For example, the third conductor 30 of the shielded cable 24 can be connected to the third contact 20'''' which forms electrical connection with the movable unit 18'1'1, as shown in Figure 16, rather than using a separate fourth conductor. In such a case, the third contact 20' ' ' ' has a tab (not shown) extending perpendicularly to the plane of the drawing which is secured in the housing, thus providing appropriate contact pressure between the third contact 20' ' ' ' and the movable unit 18 ' ' ' ' , as well as securing contact between the latch arm 18c and the shield (not shown) . In addition, as can be seen from Figure 17, in the position when the discharge lamp is not inserted (shown by solid lines), the third contact 20''1'' is not connected to either the second contact 16 or the conductive movable unit 18''''', however, in the position when the discharge lamp if fully secured (shown by broken lines) , due to the pressure from the tab 18d of the movable unit 18''''', the tab 18d, the second contact 16 and the third contact 20''1 1' are electrically connected to each other. In this embodiment, the safety-detector unit and the safety-detection circuit have the fewest number of components, thus minimizing the cost of the equipment. In the embodiments described above, the safety-detector unit 66 deliveres the signal to the power supply unit 60 allowing it to deliver electrical energy only when the terminals 68, 70 are short circuited; however, it is possible to use an arrangement in which the signal to the power supply unit 60 will be generated when the terminals 68, 70 are open. In such a case, in the socket according to the above embodiment it is necessary to implement reverse switching, namely, it is necessary to arrange the switching means so that it opens the circuit when the discharge lamp is properly secured in the socket. The lighting apparatus for discharge lamps according to this invention can be also implemented in the form of the following embodiment. The lighting apparatus for discharge lamps comprises a socket holding the discharge lamp and a power supply unit delivering electrical energy to the socket wherein a switching means is provided in the socket operated by a movable unit accommodating the discharge lamp which can rotate relative to a housing of the socket between a position at which the discharge lamp is inserted and a position at which the discharge lamp is fully secured in the socket, switching means is actuated when the discharge lamp is rotated to the position of its fully secured engagement, the switching means is comprised of any one of two contacts connected to two terminals of the discharge lamp and a third contact, and a safety-detector unit allowing delivery of electrical energy from the power supply unit only if the switching means is actuated. The advantage of such a configuration is that the number of components comprising the safety-detector unit and the safety-detection circuit is substantially reduced, thus lowering the cost of the equipment. The socket for discharge lamps can be also implemented in the form of the following embodiments. The socket for discharge lamps comprises a housing having a cavity for the reception of a discharge lamp, a contact centrally disposed in the cavity and an outer contact wherein a movable unit of conductive material is arranged in the housing cavity which can rotate relative to the housing of the socket between a position at which the discharge lamp is inserted and a position at which the discharge lamp is fully secured in the socket and which can engage mounting pins of the discharge lamp located on the sides of its base, and a latch arm is provided on the movable unit which forms electrical contact with a shield mounted on the outer surface of the housing and extends through an opening in an outside wall of the housing when the discharge lamp is in the fully-secured position. In the socket of this embodiment, the conductive latch arm is locked in the housing opening when the discharge lamp is in the fully- secured position forming electrical contact with the shield, thereby making it possible, with only few components, not only to latch the discharge lamp in the fully-secured position but also to generate a signal when the discharge lamp and the shield are in the fully-secured position.
An advantage of the lighting apparatus for discharge lamps according to the present invention is that it makes it possible to prevent electric shock during installation or replacement of discharge lamps without using lamps of special design.
Another advantage of the lighting apparatus for discharge lamps according to the present invention is that, due to considerably fewer contacts in the safety-detection circuit formed by the safety-detector unit, the presence two conductors and the movable unit, reliability of the connections in the safety-detection circuit is much higher.
A further advantage of the lighting apparatus for discharge lamps according to the present invention is that no electrical power is supplied to the socket unless the discharge lamp or the shield are properly installed, resulting in greater safety and absence of the effect of magnetic interference on other equipment .
An additional advantage of the discharge lamp socket according to the present invention is that it makes it possible to reliably prevent the discharge lamp from leaving the socket while minimizing the number of socket components.

Claims

1. A lighting apparatus for discharge lamps comprising a socket (1, 1', 1'', l'1') for receiving a discharge lamp (8), a power supply (6, 6') for supplying electrical power to the socket, the socket including a housing (10, 10', 10'', 10''') having a cavity (12) in which first and second electrical contacts (14, 16) are located for electrical connection to the discharge lamp characterized in that a movable unit (18, 18', 18'', 18''', 18'''', 18''''') is mounted in the housing and is movable relative to the housing between a first position at which the discharge lamp is inserted into the cavity and a second position at which the discharge lamp is fully secured in the socket whereby switching means (18a, 20, 22; 18a', 20*, 16; 18e, 18f, 94, 96; 18d, 20'''*, 20''''', 16) is actuated when the movable unit is at the second position, and a safety-detector unit (66) is provided in the power supply which actuates a supply power unit (60) to supply to the discharge lamp upon actuation of the switching means.
2. A lighting apparatus for discharge lamps as claimed in claim 1, wherein a metal shield (22) is located on the socket
(1), a third electrical contact (20) is mounted in the housing (10), a cam (18a) on the movable unit (18) engages the third electrical contact (20) and operates it to engage the shield when the movable unit is moved to the second position.
3. A lighting apparatus for discharge lamps as claimed in claim 1, wherein a third electrical contact (20') is mounted in the housing (10'), a cam (18a') on the movable unit (18') engages the third electrical contact and operates it to engage the second electrical contact (16') when the movable unit is moved to the second position.
4. A lighting apparatus for discharge lamps as claimed in claim 1, wherein the movable unit (18'') is a metal sheet extending along an inner surface of the housing (11) a latch arm (18c) of the movable unit (18'') is engaged with an opening (46) in the housing (11) when the movable unit is moved to the second position thereby preventing movement of the movable unit in the opposite direction, a shield (22'') is mounted over the socket (1') and includes an inward-extending lug (22a) that extends into the opening (46) thereby making electrical connection with the latch arm (18c) causing short circuiting of the safety-detector unit (66) and enabling the power supply unit (60) to deliver electrical energy to the discharge lamp.
5. A lighting apparatus for discharge lamps as claimed in claim 1, wherein the movable unit (18''') is a metal sheet extending along an inner surface of the housing (11'''), third and fourth electrical contacts (94, 96) are mounted in the housing (11'''), contact arms (18e, 18f) on the movable unit electrically engage the third and fourth electrical contacts thereby causing short circuiting of the safety-detector unit and enabling the power supply unit to deliver electrical energy to the discharge lamp.
6. A lighting apparatus for discharge lamps as claimed in claim 1, wherein the movable unit (18'''') is a metal sheet extending along an inner surface of the housing, a third electrical contact (20'''') is mounted in the housing, a tab
(18d) on the movable unit engages the third electrical contact to electrically engage the second electrical contact (16) thereby causing short circuiting of the safety-detector unit and enabling the power supply unit to deliver electrical energy to the discharge lamp.
PCT/US1998/003594 1997-02-28 1998-02-24 Lighting apparatus for discharge lamps and discharge lamp socket used therein WO1998038708A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU64385/98A AU6438598A (en) 1997-02-28 1998-02-24 Lighting apparatus for discharge lamps and discharge lamp socket used therein

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP6200597A JP3416015B2 (en) 1996-04-26 1997-02-28 Discharge lamp lighting mechanism and discharge lamp socket used therein
JP9/62005 1997-02-28

Publications (1)

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WO1998038708A1 true WO1998038708A1 (en) 1998-09-03

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1065438A1 (en) * 1999-07-02 2001-01-03 Valeo Vision Vehicle headlight equipped with a gas discharge lamp and improved means for electromagnetic shielding
FR2818867A1 (en) * 2000-12-26 2002-06-28 Koito Mfg Co Ltd DISCHARGE LAMP CONTROL CIRCUIT
EP1229615A1 (en) * 2000-08-17 2002-08-07 Mitsubishi Denki Kabushiki Kaisha Lamp socket
EP1081428A3 (en) * 1999-09-01 2002-09-18 Hella KG Hueck & Co. Mounting apparatus for a gas discharge lamp in a motor vehicle
WO2004104475A2 (en) * 2003-05-20 2004-12-02 Hella Kgaa Hueck & Co. Headlamp for vehicles
EP1847770A1 (en) * 2006-04-04 2007-10-24 Valeo Vision Lighting or signalling device, in particular for an automobile
WO2008129445A1 (en) 2007-04-19 2008-10-30 Philips Intellectual Property & Standards Gmbh Lamp

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US5237489A (en) * 1990-08-02 1993-08-17 Robert Bosch Gmbh Headlight for motor vehicles
JPH07114819A (en) * 1993-10-15 1995-05-02 Matsushita Electric Works Ltd Illuminating lamp device

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US1822161A (en) * 1929-09-06 1931-09-08 Henry Cole Company Switch
US5237489A (en) * 1990-08-02 1993-08-17 Robert Bosch Gmbh Headlight for motor vehicles
JPH07114819A (en) * 1993-10-15 1995-05-02 Matsushita Electric Works Ltd Illuminating lamp device

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Title
PATENT ABSTRACTS OF JAPAN vol. 95, no. 8 29 September 1995 (1995-09-29) *

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1065438A1 (en) * 1999-07-02 2001-01-03 Valeo Vision Vehicle headlight equipped with a gas discharge lamp and improved means for electromagnetic shielding
FR2795691A1 (en) * 1999-07-02 2001-01-05 Valeo Vision MOTOR VEHICLE PROJECTOR EQUIPPED WITH A DISCHARGE LAMP AND IMPROVED ELECTROMAGNETIC SHIELDING MEANS
EP1065438B2 (en) † 1999-07-02 2011-01-12 Valeo Vision Vehicle headlight equipped with a gas discharge lamp and improved means for electromagnetic shielding
EP1798466A1 (en) * 1999-07-02 2007-06-20 Valeo Vision Vehicle headlight equipped with a gas discharge lamp and improved means for electromagnetic shielding
US6474856B2 (en) 1999-07-02 2002-11-05 Valeo Vision Motor vehicle headlight equipped with a discharge lamp and with improved electromagnetic screening means
EP1081428A3 (en) * 1999-09-01 2002-09-18 Hella KG Hueck & Co. Mounting apparatus for a gas discharge lamp in a motor vehicle
US6680575B1 (en) 2000-08-17 2004-01-20 Mitsubishi Denki Kabushiki Kaisha Lamp socket
EP1229615A4 (en) * 2000-08-17 2003-07-23 Mitsubishi Electric Corp Lamp socket
EP1229615A1 (en) * 2000-08-17 2002-08-07 Mitsubishi Denki Kabushiki Kaisha Lamp socket
US6583585B2 (en) 2000-12-26 2003-06-24 Koito Manufacturing Co., Ltd. Discharge lamp lighting circuit
FR2818867A1 (en) * 2000-12-26 2002-06-28 Koito Mfg Co Ltd DISCHARGE LAMP CONTROL CIRCUIT
WO2004104475A2 (en) * 2003-05-20 2004-12-02 Hella Kgaa Hueck & Co. Headlamp for vehicles
WO2004104475A3 (en) * 2003-05-20 2005-01-13 Hella Kg Hueck & Co Headlamp for vehicles
US7513648B2 (en) 2003-05-20 2009-04-07 Hella Kgaa Hueck & Co., Headlamp for vehicles
EP1847770A1 (en) * 2006-04-04 2007-10-24 Valeo Vision Lighting or signalling device, in particular for an automobile
WO2008129445A1 (en) 2007-04-19 2008-10-30 Philips Intellectual Property & Standards Gmbh Lamp

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