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Publication numberUS3870946 A
Publication typeGrant
Publication date11 Mar 1975
Filing date13 Dec 1973
Priority date13 Dec 1973
Also published asCA1013812A1
Publication numberUS 3870946 A, US 3870946A, US-A-3870946, US3870946 A, US3870946A
InventorsRobert E Sandorf
Original AssigneeNordson Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Quick connect modular voltage multiplier
US 3870946 A
Abstract
A multiplier module for stepping up low voltage from an external source for application to a spray gun electrode via a coaxial cable, the module being encapsulated and provided with female connectors to facilitate quick connect/disconnect operation and its components uniquely arranged to minimize high voltage hazards.
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Description  (OCR text may contain errors)

United States Patent 1191 1.111 3,870,946 Sand0rf 1 51 Mar. 11, 1975 1541 QUICK CONNECT MODULAR VOLTAGE 3,599,038 8/1971 Skidmorc 321/15 3,748,538 7/1973 Shckcrjiun ct a]. 317/10! R MULTIPUER 3,771,024 11/1973 Dumas 321/15 [75] lnventor: Robert E. Sandorf, Richfield, Ohio [73] Assignee: Nordson Corporation, Amherst, Primary Examiner-William H. Beha. Jr.

Ohio Attorney, Agent, or Firm-Wood, Herron & Evans [22] Filed: Dec. 13, 1973 [2]] Appl. No.: 424,546 ABSTRACT A multiplier module for stepping up low voltage from 152] US. Cl 321/15, 174/52 PE, 317/3 n xternal source for application to a spray gun elec- [51 1 Int. Cl. H02m 7/10 trode i a axi l a l h m ule eing encapsu- 1581 Field of Search 321/15; 174/52 PE; 317/3, lated and provided with female connectors to facilitate 3l7/l0l R; 239/15 quiek connect/disconnect operation and its components uniquely arranged to minimize high voltage ha- [5 References Cited zards.

UNITED STATES PATENTS 12 Claims, 8 Drawing Figures 3,4l2,l98 ll/l968 Wallis 239/15 QUICK CONNECT MODULAR VOLTAGE MULTIPLIER BACKGROUND OF THE INVENTION This invention relates to a multiplier module for stepping up a low voltage from an external source for appli cation to the electrode of a spray gun via a coaxial cable and more particularly to an encapsulated module which is provided with female connectors to facilitate quick connect/disconnect operations and has components uniquely oriented to minimize high voltage ha zards.

In the fieldof electrostatic spray coating of paint, powders or the like, a spraying device in the form of a gun is provided for spraying paint, powder, or the like from the nozzle thereof onto an article which is to be coated. In most instances, the article is maintained at ground potential and the particles, as they leave the spray gun nozzle, are charged in an electrostatic field to a very high potential, on the order of 50-200 Kv, by an electrode mounted on the gun near the nozzle which is connected to a high voltage supply. The electrically charged sprayed particles are attracted to the electrically grounded article and adhere thereto.

In most electrostatic spray coating equipment, the high voltage power supply is normally remotely located with respect to the spraying nozzle itself, e.g., on the floor at a distance from the operator, and the particle charging high voltage brought to the gun by a coaxial cable for application to the gun electrode. This is especially true of applications employing hand held spray guns, the reason being that the power supply itself is generally quite large and heavy, and hence too bulky and massive to be incorporated in a spray gun designed.

for manual use.

Typically, high voltage power supplies for use in electrostatic spray coating equipment include in source of relativelylow voltage, e.g., 8 Kv peak-to-peak, and a voltage multiplier circuit for increasing the output of the low voltage source to the desired high voltage charging potential, 50-l00 Kv. The low voltage source normally includes a stepup transformer which produces at its output a signal typically having a magnitude of 8 Kv peak-to-p eak. This 8 Kv signal is then applied to the inputofa voltage multiplier assembly, usually taking the form of multiple interconnected diode/- capacitor voltage doubling stages, which produces at its output a very high direct current voltage which typically is in the range of 50-100 Kv. The high voltage output of the voltage multiplier is then connected to the electrode of a spray gun via a coaxial cable. To facilitate quick connection and disconnection between the cable and the high voltage multiplier output, the cable is provided with a male connector plug and the multiplier with a female connector socket, which socket is usually mounted to the chassis to which the mutiplier and low voltage source are also mounted. Thus, by merely engaging and disengaging the cable plug and multiplier socket, the gun electrode can be energized and de-energized, respectively.

In the operation of electrostatic spray-coating equipment of the type described generally above, failures often occur preventing the supply of high voltage potential to the coaxial cable and hence to the gun electrode. These failures are generally caused by either a malfunction in the electrical connector which connects the output ofthe voltage multiplier to the coaxial cable,

or a malfunction in the voltage multiplier circuit itself. Since both of these failures manifest themselves in the same manner, i.e., no high voltage is applied to the spray gun electrode, a repairman faced with this type of failure may have to replace the connector, the voltage multiplier, or both in order to correct a mulfunction. Such repairs are costly because of the considerable time required to locate the cause(s) of the failure and then remove and replace the failing element or elements.

A further problem associated with existing high voltage power supplies for electrostatic spray coating equipment arises from the phenomenon of corona discharge. When extremely high voltages are developed in a power supply, the connecting wires to the high voltage often contribute to circuit losses in the form of a corona discharge from the wires themselves. In order to overcome these losses, the physical configuration of the connecting wires carrying the high voltage must be shaped to avoid sharp bends and hence to prevent concentrations of electrical charge at any point along the wire. Repairmen making repairs to a voltage multiplier and/or the female socket output therefrom, often fail to correctly shape the interconnecting high voltage wire, with the result that increased corona discharge is frequently experienced after the repairs have been made.

In view of the foregoing difficulties, it is a primary objective of the invention to provide a multiplier module for stepping up low voltage from an external source to a high voltage for application to the electrode of a spray gun which is adapted for quick connect/disconnect operation, and minimizes high voltage hazards and power loss due to corona discharge.

The foregoing and other objects, advantages and features of the invention are accomplished by completely encapsulating the multiplier module in dielectric material, incorporating female connectors in the encapsulated module for facilitating quick connect/disconnect operation, and orienting the module components and female connectors in a unique configuration.

Included in the module, in a preferred embodiment thereof, is a voltage multiplier circuit consisting of multiple diode/capacitor voltage doubling stages arranged in and elongated stack, with the high voltage output and low voltage input terminals thereof disposed at opposite ends of the stack. The multiplier is axially aligned with an elongated gun resistor, the adjacent end of which is electrically connected to the high voltage terminal of the voltage multiplier. At least one, and preferably two, deep elongated female connector sockets are disposed parallel to the axially aligned voltage multiplier and resistor combination, placing the outer open end of each socket adjacent the low voltage multiplier input terminal, and the inner closed end which is at high voltage adjacent the outermost end of the elongated resistor. Seated within the innermost end of each socket is an electrical contact, preferably a short coil spring, which connects to the outer end of the elongated resistor via a wire which is smoothly curved to minimize corona discharge. A spherical conductive ball is disposed outboard of each coil spring/bent wire junction to facilitate electrical connection between the coil and the wire and to further minimize corona discharge.

The entire assembly is encapsulated, except for the outer ends of the female connectors sockets, these protruding through the exterior of the encapsulation and therefore accessible for receiving elongated male connector probes to which spray gun electrodes are connected via coaxial cables for energization by the high voltage provided by the voltage multiplier circuit. Extending through one wall of the encapsulated assembly adjacent the elongated female socket openings and electrically connected to the low voltage input of the voltage multiplier are two additional female connectors to facilitate energization of the voltage multiplier with a low voltage from an external source. The encapsulated assembly is fastened to a mounting chassis with the chassis contacting the assembly adjacent the sur' face thereof containing the open ends of the elongated female sockets, thereby maximizing the distance, and hence the electrical standoff, between the chassis at the open end of the high voltage socket and the high voltage terminals of the voltage multiplier seated deep within the multiplier module to thereby reduce high voltage hazards.

In accordance with a further refinement of the invention, internal corona discharge is further minimized by utilizing an encapsulating material which has a low moisture absorption characteristic. Additionally, since the voltage multiplier components are brittle and easily broken by stresses on them, the encapsulating material should have a low shrinkage characteristic to minimize stress on encapsulated components.

The foregoing and other objects, features and advantages of the invention will become more clear from the following detailed description of the preferred embodiment thereof taken in connection with the drawings which form a part of the original disclosure.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram in perspective showing an electrostatic spray coating system including the multiplier module of the invention;

FIG. 2 is an electrical circuit diagram for a voltage multiplier of the type used in the multiplier module of the invention;

FIG. 3 is an end elevational view of the voltage multiplier assembly;

FIG. 4 is a side elevational view of the voltage multiplier assembly as viewed from'the left along lines 4-4 of FIG.'3;

FIG. 5 is aside elevational view of the voltage multiplier assembly as viewed from the right along lines 55 of FIG. 3;

FIG. 6 is a horizontal sectional view taken through the multiplier modules;

FIG. 7 is a vertical view taken along section line 77 of FIG. 6; and

FIG. 8 is a vertical sectional view taken along section line 8-8 of FIG. 6.

DETAILED DESCRIPTION Referring first to FIG. 1, an electrostatic spray-.

coating system is schematically shown with a power supply, shown generally at 10, and a spray gun, shown The power supply 10 includes a relatively low voltage power supply module 18 which receives alternating current electricity from the plug 14 via a power cable 20. The low voltage power supply 18 is operative to convert the standard alternating current electricity received on the power cable 20 into an alternating current output having 8Kv peak-to-peak amplitude at a frequency of approximately 15 kHg. This output of the low voltage power supply 18, while having very high voltage with respect to the voltage received from the power cable 20, is nowhere near high enough for electrostatic spray-coating applications. Consequently, the 8,000 volt peak-to-peak output must be converted to a much high voltage by a multiplier module, which, according to this invention, is shown generally at 22. The 8,000 volt peak-to-peak output voltage is transmitted from the low voltage power supply 18 to the multiplier module 22.via wires 24 which have male plugs 26, such as banana plugs or the like, at the free end thereof. These plugs 26 are designed to plug into female sockets 28 which are accessible from the exterior of the multiplier module 22.

Encapsulated within the module 22 and electrically connecting with the female sockets 28 is an elongated voltage multiplier assembly 30 which will be described in greater detail later. The low voltage input terminals of the voltage multiplier 30 are located adjacent the female sockets 28 which themselves, for reasons which will become more clear later, are located closely adjacent the support panel 32 which forms one wall of the chassis that surrounds the power supply.

Disposed further away from the panel 32 than the voltage multiplier 30 are a pair of gun resistors 34 which are electrically connected at one end to the high voltage output of the voltage multiplier 30and at their other end to a contact member 36 disposed deep within the interior of a female socket 38.

The high voltage at the electrical contact member 36 is electrically connected to the coaxial cable 16 and the spray gun 12 via a male connector shown generally at 40 which includes an elongated member 42 made of an insulator having a metal or conductive tip 44 disposed at its extreme end and electrically connected to the center conductor of the coaxial cable 16. This conductive tip 44, when the elongated member 42 is disposd in the female socket 38, electrically contacts the contact member 36 thereby permitting the high voltage appearing at the contact member 36 to be transmitted to a connected spray gun.

The male connector 40 includes a swivel nut, shown generally at 46 which threadably engages an exteriorly threaded cylindrically shaped connector of the type generally shown at 48, the connector 48 being axially aligned with the female socket 38 to thereby permit the male connector 40 to be secured in position to permit electrical connection between the high voltage gener ated by the voltage multiplier 30 and the spray gun electrode.

By reason of the physical configuration for the multiplier module 22, as will be described in greater detail later, the low. voltage input can be quickly disconnected from the low voltage supply by simply unplugging each of the male plugs 26. Additionally, the spray guns can be simply disconnected from the high voltage output of the multiplier module by simply unscrewing the swivel nut 46 from the connector 48 and withdrawing the elongated male connector member 42 from the female socket 38. As such, the electrical connections to-the multiplier module are quickly and easily made or broken. Additionally, by reason of the modular assembly which will be described in greater detail later,

should be assembly fail to provide a high voltage output to be connected to a spray gun, the module 22 can be easily removed from the power supply by simply disconnecting the securing bolts 50 from the embedded nuts in the module 22. In this manner the module 22 can be quickly removed from the power supply and a new module quickly installed. As such, failures associated with the multiplier module can be remedied by replacing the module itself in this quick and easy manner. Additionally, as will become more clear later, since the module itself is designed to reduce hazards of high voltage as well as loss due to corona discharge, by simply replacing a whole module 22 the problems of corona discharge associated with repairing and/or replacing parts is eliminated.

FIG. 2 shows a schematic diagram for a known voltage multiplier circuit. This voltage multiplier circuit has input terminals 60 and 62 for receiving an alternating current input voltage typically having a peak-topeak voltage of approximately 8 Kv and having a frequency in the range of between IOI5 kHz, although the input voltage may have other frequencies and peakto-peak voltages. The voltage mutliplier circuit itself includes two stacks of series connected capacitors, the first stack including capacitors 64, 65 and 66 with the second stack including capacitors 68, 69 and 70. The voltage multiplier circuit also includes a plurality of shunting diodes 72, 73, 74 and 75 and also a plurality of diagonally shunting diodes 78, 79 and 80 connected as shown.

In operation, the voltage multiplier circuit of FIG. 2

responds to the input voltage of the type described generally above the produce a very high output voltage at the mutliplier circuit output terminal 82. The exact voltage multiplication that occurs will depend on the number of series connected diode/capacitor stages in the mutliplier. It will be recognized by those skilled in the art that numerous other voltage multiplier circuits are known in the prior art and that these circuits may also be utilized in the present multiplier module. Additionally, the multiplier may include a very high resistance bleeder resistor connected between ground and the high voltage output terminal for discharging the capacitors in the multiplier when the multiplier is not in use.

The particular circuit configuration shown in FIG. 2, however, is particularly advantageous because it lends itself to being constructed in an elongated stack. FIG. 3, for example, is an end view of an assembly voltage multiplier having a circuit configuration like that shown in FIG. 2. The circuit elements which can be viewed in FIG. 3 correspond identically with those identified in the circuit diagram of FIG. 2.

The assembly details of the voltage multiplier circuit, however, are better understood by reference to FIGS. 4 and 5 which show side elevational views of the voltage multiplier assembly shown in FIG. 3 taken from the left and from the right respectively. As viewed in FIG. 4, for example, the first string of series connected capacitors including capacitors 64, 65 and 66 also include a plurality of other capacitors 84 which are also series connected to the previously mentioned capacitors in the first string. Each capacitor in this first string comprises typically a disc ceramic capacitor having a cylindrical body with electrical connectors disposed at opposite ends thereof along the axis of the body itself. Each of the capacitors in the first group of series connected capacitors are axially aligned and the capacitor connections soldered to connector tabs 86, each of which has an ear portion like that shown generally at 88 in FIG. 3 which extends outwardly beyond, the body of each capacitor to permit the shunting and diagonal shunting diodes of the voltage multiplier to be connected electrically to the capacitors.

It will be noted from FIGS. 3-5, that each capacitor whichcomprises one of a plurality ofcapacitors in each series connected string is axially aligned to form a stack. The shunting diodes, such as diode 75, are all disposed on one side of the two stacks of series connected capacitors while the diagonal shunting diodes. such as diode 80, are disposed on the other side of the two stacks of series connected diodes.

The output terminal 82 of the voltage multiplier assembly has a threaded stud 90 soldered or otherwise connected too the outermost connector 86 on the first string of series connected diodes. A bolt 92 engages the threaded stud 90 and this bolt can be used to secure solder lugs or the like to the output terminal of the voltage multiplier. The input terminals 60 and 62, on the other hand, are constructed of elongated bodies with an outer circumference being hexagonally shaped. The elongated bodies have a cylindrical bore 94 extending longitudinally through the elongated bodies and centered substantially about the longitudinal axis thereof.

This cylindrical bore 94 provides the female socket,

identified as 28 in FIG. 1, for receiving male plug connectors 26 to thereby electrically connect the input terminals 60 and 62 of the voltage multiplier assembly to the low voltage input received from a low voltage power supply, such as 18 in FIG. 1.

The elongated bodies which comprise the input terminals 60 and 62 are disposed with their longitudinal axis being arranged perpendicularly to the longitudinal axes of the two stacks of series connected capacitors. The input terminal 60 is soldered to the connector 86 which in turn is soldered to the capacitor 64. The input terminal 62 is also soldered to a connector 86 which is in turn soldered to the capacitor 68.

The voltage multiplier assembly as shown in FIGS. 3-5 comprises only a portion of the multiplier module of this invention. The remainder of the module is better shown in FIG. 6' which shows a horizontal sectional view taken through the module 22. The voltage multiplier, shown generally at 30, is of the type previously described and is located within the module 22 adjacent the mounting panel 32 with the low voltage input terminals 60, 62 being disposed adjacent the panel 32. The high voltage output, shown generally at 82, for the voltage multiplier 30 is disposed away from the mounting panel 32 to reduce electrical shock hazard and corona discharge.

Mountedwithin the module 22 are two elongated interiorly threaded bodies 51 which are disposed at the end of module 22 adjacent the mounting panel 32. These bodies 51 are so positioned that the interior threaded portion thereof is accessible through the surface of the module 22 so that the threaded bolts 50 can pass through the mounting panel 32 and engage the interiorly threaded portion of the bodies 51 thereby securing the module 22 of the mounting panel 32. While a particular mounting approach has been described, it will be clear to those of skill in the art that other mounting approaches will permit the module 22 to be rigidly affixed to a mounting panel 32. For example, an alternative approach could involve embedding a threaded bolt in the module 22 and having the threaded portion of these bolts extend outwardly from the module 22 through aligned holes in the mounting panel 32. The theaded ends of these bolts are then engaged by threaded nuts tightened agains the mounting panel 32 to thereby secure the assembly to the panel 32. Other approaches may also be'utilized to secure the module 22 to the panel 32.

The module 22 includes two elongated tubes 100 and 101 which are disposed within the module 22 on either side of the voltage multiplier 30. These tubes 1 and 101 are preferably constructed of fiberglass or other insulative material. The open end of these tubes 100 and 101 extend outwardly of the module 22 wall adjacent the mounting panel 32 and engages a mating hole in the panel 32. The extreme outward end of the tubes 100 and 101, however, extend outwardly from the module 22 a distance sufficient that the end of the tubes 100, 101 will be flush with the exterior surface of the mounting panel as shown generally at 102.

Disposed at the extreme inner end of the tube 100 and 101 are the contact members or end plugs 36. These end plugs 36 are contructed with interior fitting portions 104, 105 which fit snugly into the extreme inner end of the tubes 100, 101, respectively. The plugs 36 also include end cap portions 106, 107 which have flanges extending radially outwardly of the portions 104, 105 so as to be in abutting relation with the end of the tubes 100, 101.

The plugs 3.6 are preferably made of aluminum or some other easily shaped metal which is electrically conductive. Each of the plugs 36 has a hole passing therethrough which is aligned with the longitudinal axis of the tubes l00, 101 and these holes permit threaded bolts 108, 109 to pass therethrough. The heads of these bolts 108, 109 are located within the tubes 100, 101 and are provided to secure coiled spring contacts 110, l ll to the plugs 36 respectively.

Disposed on the opposite side of the plugs 36 from the heads of the bolts 108, 109 are nuts 112, 113 which are tightened down against the exposed surface of the cap portions 106, 107 respectively to thereby'secure the coiled spring contacts 110, 111 to the plugs 36.

The threaded portion of the bolts 108, 109 extend beyond the nuts 112, 113 so that electrical contact can be made with gently bent wires 114, 115-. These wires 114, 115 are bent around and are in electrical contact with the theaded portion of the bolts 108, 109 respectively. These wires 114, 115 are secured in electrical contact with the bolts 108, 109 respectively by interiorly threaded ball connectors 116, 117 which threadably engage the exposed portion of the bolts 108, 109. These ball connectors 116, 117 are tightened down to effect the electrical connection of the wires 114, 115 to these bolts 108, 109. The ball connectors 116, 117 are made of an electrically conductive metal and are spherically shaped so as to resist corona discharge.

The wires 114, 115 electrically interconnect the bolts 108, 109 with the gun resistors 34. These wires 114, 115 are gently bent in the regions shown generally at 118 and 119 respectively so as to prevent corona discharge along the length of these wires as well.

The gun resistors 34 are elongated cylindrically shaped resistors having threaded connector members at opposite ends thereof to permit easy electrical connection to other components. At the high voltage output 82 of the voltage mutliplier 30, the threaded member 90 has a bracket 120 electrically connected by soldering or other connections to the capacitor 66 and this threaded member 90 extends through the resistor mounting bracket 120 to engage internal threads (not shown) of the resistor 34a. By tightening down this resistor 34a agaisnt the mounting bracket 120, this bracket 120 can be fixed in spacial relationship to the remaining module parts. The mounting bracket 120 is preferably made of an electrically conductive material such as copper, aluminum or the like and is shaped with a bend so that it can electrically engage the resistor 34b and not connect electrically to any other portions of the voltage multiplier 30. As viewed in FIG. 6, a threaded screw 121 passes through the mounting bracket 120 to engage the threaded connector portion of the resistor 34b. By tightening down this resistor 34b, onto the screw 121, the resistor 34)) can be electrically connected to the high voltage output of the voltage multiplier assembly 30 as well as rigidly positioned with respect to the other module parts. it should also be noted that the gun resistors 34 are thus mounted in axial alignment with the voltage multiplier 30.

Referring again to the voltage multiplier input terminals 60, 62 as shown in FIG. 8, these input terminals comprise elongated bodies having an exterior hexagonal shape and an interior cylindrical bore. These elongated bodies are soldered or otherwise electrically connected to the low voltage inputs to the voltage mutliplier assembly 30 of the type previously described with the longitudinal axis thereof arranged perpendicularly to the axis of the capacitor stacks which comprise a voltage multiplier. The elongated bodies are sufficiently long so that they are flush mounted, as viewed generally at 63, with the upper surface of the module 22- thereby permitting easy electrical connection with the low voltage input to the voltage multiplier. Typically, a banana plug such as the plugs 26 in FIG. 1 are pressed into the interior bore of the connectors 60, 62 to thereby electrically connect with the low voltage input to the voltage multiplier assembly. Since banana plugs or the like are used to make this electrical connection, the low voltage source can easily be disconnected from the low voltage input to the module simply by pulling the banana plug out of engagement with the connectors 60, 62.

All of the. above mentioned components of the module 22 are encapsulated in a material indicated generally at 124 which is in the shape of an elongated rectangular solid. The encapsulating material itself preferably has low moisture absorption and low shrinkage characteristics. Low moisture absorption is necessary to reduce corona discharge within the module. On the other hand, low shrinkage is necessary to prevent warping of the assembly as well as component destruction. Since the voltage multiplier uses diodes which are very brittle, shrinkage of the modular assembly must be minimized or the diodes will crack thereby causing an electrical failure in the voltage multiplier. A two part epoxy such as the two part epoxy made of Stycast 2850 FT Blue mixed with catalyst No. 11 and manufactured by Emerson Cuming is a suitable encapsulating material.

Other encapsulating materials which do not absorb moisture and do not shrink may also be used.

In order to make an electrical connection with the high voltage output of the voltage multiplier 30 which is electrically connected in a manner described above with the coiled spring connectors 110, 111, an elongated male plug 40 must be inserted into the open ends of the tubes 100, 101. In the preferred embodiment of this invention, this elongated plug 40 is constructed on the end of a coaxial cable 16 which has an electrically conductive outer braid 125 and a centrally disposed electrical conductor 126 which is electrically insulated and spaced from the braid 125 by an insulating material 127. The outer braid 125 is stripped from the end of the coaxial cable 16 from the point shown generally at 128 so that the center conductor 126 and the insulating material 127 can extend into the socket 38 formed by the tube 101 as indicated generally at-42. Located at the extreme inner end of this portion of the coaxial cable from which the braid 125 has been stripped is the circular contact tip 44 made of an electrically conductive material and electrically connected by soldering or other electrical connection to the center conductor 126. This circular tip 44 is in electrical contact with the coiled spring contact 1 11 so as to permit electrical connection between the center conductor 126 of the coaxial cable l6 and the high voltage output of the voltage multiplier 30. The portion of the coaxial cable shown at 42 from which the outer braid 125 has been stripped must be of a sufficient length so as to extend into the tube 101 to permit some compression of the coiled spring connector 111 so that a good electrical contact can be made between the connector 111 and the tip 44. When this compression of the coiled spring connector 111 occurs, however, a force is exerted on the portion of the cable 42 to force the cable out of the tube 101. The coaxial cable 16, however, is secured in position by the swivel nut assembly shown generally at 46.

The assembly shown at 46 includes the threaded, somewhat cylindrically shaped body 48 which is secured to the outer surface of the mounting panel 32 in alignment with the tube 101. A second body like the threaded body 46, although not shown in FIG. 6, is attached to the outer surface of the mounted panel 32 in alignment with the tube 100 thereby permitting a second coaxial cable to be simultaneously connected to the high voltage output of the voltage multiplier 30.

The assembly 46 also includes a metallic body 131 which has a central circular aperture passing therethrough having a diameter slightly smaller than the diameter of the insulated portion 127 of the coaxial cable 16. The portion 42 of the cable extends through this aperture of the body 131 and, because this diameter is smaller than that of the insulated portion 127, the body 131 compresses the insulated portion 127 and becomes securely affixed to the insulated portion 127. At the point shown generally at 128, the metal braid 125 of the coaxial cable 16 is electrically connected to the body 131 thereby further securing this body 131 to the coaxial cable 16. The body 131 is of a diameter which is sufficient to engage the outer end of the body 48 as shown at 132 thereby permitting electrical connection between the outer braid 125 and the mounting panel 32.

The body 131 additionally includes a tapered flange portion shown generally at 133. This-tapered flange 133 engages a similar shaped tapered flange 134 of a threaded cylindrically shaped swivel nut 135 which threadably engages the body 48. By tightening the nut 135 onto the body 48, the body 131 becomes locked against the end of the body 48 thereby securing the coaxial cable 16 to the mounting panel 32. As such, the circular tip 44 will be secured in electrical contact with the coiled spring connector 111 thereby permitting electrical connection of an electrostatic spray gun at the opposite end of the coaxial cable 16 at the gun (FIG. 1) with the high voltage output of the voltage multiplier 33.

In operation, the modular assembly 22 shown in FIG. 6 is electrically connected in a manner described earlier to a relatively low voltage alternating current source at the low voltage input connectors 60, 62. The voltage multiplier 30 multiplies the input voltage in a manner well known in the art for voltage multipliers of the type previously described and produces a high voltage DC signal at its output. This high voltage passes through the bracket 120, the gun resistor 34!), the gently bent wire to the coiled spring connector 111. This connector 111 is in electrical contact with the circular tip 44 disposed at the end of the coaxial cable 16. At the opposite erid of this cable 16 (FIG. 1), is an electrostatic spray gun having a high voltage probe electrically connected to the center conductor 126 of the coaxial cable 16. In this manner, the spray gun probe can be electrically connected to the high voltage output of a voltage multiplier. It will be clear that a second spray gun can be connected via the other connector in the modular assembly.

In the case of a failure in the electrical circuitry which, as indicated earlier, frequently occurs in the electrical connector or in the voltage multiplier, the module 22 can be easily disconnected and replaced in the following manner. The coaxial cable 16 can be disconnected from the modular assembly 22 simply by unscrewing the swivel nut 46 and withdrawing the portion 42 from the tube 101. Then, the banana plugs or similar input connection to the terminals 60, 62 are electrically removed. The bolts 50 are then unscrewed and the modular assembly can be completely removed. This process, when reversed, will permit the installation of a similar module 22 to replace the defective module. As such, replacing the module is an extremely simple operation as compared to the extended repair time required to make a similar repair in prior art power supplies.

While the foregoing description has been made with particular emphasis on a preferred embodiment of the invention, it will be recognized by those skilled in the art that numerous modifications in form may be made thereto without departing from the spirit and scope of the invention as defined by the following claims.

What is claimed is:

l. A quick connect/disconnect modular voltage multiplier assembly comprising, in combination:

an elongated voltage multiplier with low voltage input terminals disposed at one end thereof and a high voltage output terminal disposed at the opposite end thereof;

at least one elongated female socket with an open end for receiving an elongated plug with a conductive tip, said socket being disposed in substantially parallel relation to said elongated voltage multiplier with said open end being disposed adjacent said input terminals, said socket including a closed end disposed adjacent said high voltage output terminal;

an electrical connection means disposed at said closed end of one said socket for electrically connecting the tip of an elongated plug when inserted into said socket, with said high voltage outputterminal, said electrical connection being physically shaped to minimize corona discharge;

an encapsulation having at least first and second differently disposed external faces for completely surrounding and supporting said voltage multiplier, said socket and said electrical connection means, said encapsulation being shaped so that said open end of each said socket and said input terminals are accessible through said first and second faces, respectively, of said encapsulation so that external plugs can quickly connect or disconnect relative thereto, by movement thereof in different directions corresponding to the directions of said differently disposed first and second external faces.

2. The quick connect/disconnect modular voltage multiplier assembly of claim 1 wherein said input terminals comprise elongated hollow bodies having a centrally located cylindrical bore, said hollow bodies being disposed to permit access to said cylindrical bore so that male electrical connectors can quickly connect or disconnect to said low voltage input terminals.

3. The quick. connect/disconnect modular voltage muliplier assembly of claim 2 wherein the axis of each said cylindrical body forming said input terminals is disposed substantially perpendicularly to the axis of each voltage output terminal and said electrical connection means, said resistor being in substantial axial alignment with said elongated voltage multiplier, one said resistor electrical terminal being connected to said high voltage output terminal and the other said resistor electrical terminal being connected to said electrical connection means.

6. The quick connect/disconnect modular voltage multiplier of claim 5 additionally including an electrically conductive mounting bracket connected to said high voltage output terminal, said bracket having at least one hole therethrough,

a threaded screw passing through said hole, and

at least one said resistor electrical terminal including an interiorly threaded connector engagable' with said threaded screw when said screw is passed through said bracket hole.

7. A quick connect/disconnect modular voltage multiplier assembly comprising, in combination:

a solid encapsulation formed of an insulating material having a low shrinkage characteristic and a low water absorption characteristic;

an elongated voltage multiplier disposed completely within said encapsulation, said voltage multiplier including low voltage input terminals at one end thereof and a high voltage output terminal disposed at the other end thereof;

electrically conductive input terminals electrically connected to said low voltage input terminals to said voltage multiplier, said input terminals being elongated and having a centrally disposed cylindrical bore, the axis of said cylindrical bore being arranged perpendicular to the axis of said elongated voltage multiplier, said cylindrical bore being accessible through the surface of said encapsulation;

a pair of elongated cylindrical tubes made of insulating material, said tubes being disposed on either side of said voltage multiplier with the longitudinal axis of each said tube being parallel to the longitudinal axis of said multiplier, one end of each said tube being accessible through the surface of said encapsulation, said accessible end of each tube being disposed adjacent said voltage multiplier I input terminals;

electrical connector means disposed at the inner end of each said tube, said electrical connector means being shaped to minimized corona discharge;

a pair of elongated electrical resistors disposed in axial alignment with theaxis of said voltage multipliei', one end of each said resistors being electrically connected to said high voltage output terminal;

an electrical connecting wire for connecting each said connector disposed at the inner end of each said tube with the opposite end of one said resistor, each said wire being shaped to minimize corona discharge.

8. The quick connect/disconnect modular voltage multiplier assembly of claim 7 wherein said electrical connector disposed at the inner end of each said tube comprises a coiled spring connector, a screw and a threaded ball connector, said coiled spring being disposed within said tube, said spring connector being positioned by said screw in electrical contact therewith and passing through the end of said tube, said screw being engaged by one said wire and also engaged by said threaded ball connector tightened down on said screw to form an electrical contact between said coiled spring and said wire, said ball connector being operative to substantially reduce corona discharge associated with said connector disposed at the inner end of each said tube.

9. The'quick connect/disconnect modular voltage multiplier assembly of claim 7 wherein said encapsulation material is made of a material which has a low moisture absorption characteristic to minimize corona discharge and a low shrinkage characteristic to prevent componentdestruction.

10. The quick connect/disconnect modular voltage multiplier assembly of claim 7 including means to mount said assembly to a conductive panel, said mounting means being disposed adjacent said accessible end of said tubes so that said electrical connector means is disposed away from said panel to minimize high voltage hazards.

11. A quick connect/disconnect modular voltage multiplier assembly comprising, in combination:

an elongated voltage multiplier with low voltage 'inputterminals disposed at one end thereof and a high voltage output terminal disposed at the opposite end thereof;

at least one elongated socket with an open end for receiving an elongated plug with a conductive tip, said open end being disposed adjacent said input terminals, said socket including a closed end disposed adjacent said high voltage output terminal;

an electrical connection means disposed at said closed end of one said socket for electrically connecting said tip of said elongated plug inserted in said socket with said high voltage output terminal, said electrical connection means including a coiled spring connector disposed at said closed end of each said socket, said coiled spring being positioned at said closed end by a threaded screw electrically connected to said coiled spring connector and passing through said closed end of each socket, the exposed end of said screw passing through said closed end and electrically engaging a wire, said wire being gently bent and connected at its opposite end to said high voltage output terminal, said wire being secured to said screw by an interiorly threaded ball connector which is tightened down onto said screw, said ball connector and said gently bent wire being shaped to reduce corona discharge of said electrical connection means; and

an encapsulation for completely surrounding and supporting said voltage multiplier, said socket and said electrical connection means, said encapsulation being shaped so that said open end of each socket and said input terminals are accessible through the encapsulation so that an external plug can quickly connect or disconnect to each said terminaL 12. A quick connect/disconnect modular voltage multiplier assembly comprising in combination:

a solid encapsulation formed ofan insulating material having a low shrinkage characteristic and a low water absorption characteristic;

an elongated voltage multiplier disposed completely within said encapsulation, said voltage multiplier including low voltage input terminals at one end thereof and a high voltage output terminal disposed at the other end thereof;

electrically conductive input terminals electrically connected to said low voltage input terminals to said voltage multiplier, said input terminals being elongated and having a centrally disposed cylindrical bore, the axis of said cylindrical bore being arranged perpendicular to the axis of said elongated voltage multiplier, said cylindrical bore being accessible through the surface of said encapsulation;

a pair of elongated cylindrical tubes made of insulating material, said tubes being disposed on either side of said voltage multiplier with the longitudinal axis of each said tube being parallel to the longitudinal axis of said multiplier, one end of each said tube being accessible through the surface of said encapsulation, said accessible end of each tube being disposed adjacent said voltage multiplier input terminals; I

electrical connector means disposed at the inner end of each said tube, said electrical connector means being shaped to minimize corona discharge;

a pair of elongated electrical resistors disposed in substantial axial alignment with the axis of said voltage multiplier, at least one end of each said resistor including an interiorly threaded electrical connection;

a mounting bracket electrically connected to said high voltage output terminal, said mounting bracket having at least two holes therethrough;

a plurality of threaded screws each passing through one said hole in said bracket and engaging one said interiorly threaded resistor connection; and

an electrical connecting wire for connecting each said connector disposed at the inner end of each said tube with the opposite end of a different one of said resistors, each said wire being shaped to minimize corona discharge.

* l =I l UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,870,946

DATED I March 11, 1975 |NVENTOR(S) Robert E. Sandorf It is certified that error appears tn the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 20, change "50-200 KV" to -50l00 KV.

Column 2, line 6, change "mulfunction" to -malfunction.

Column 2, line 44, change "and" to an-.

Column 3, line 51, insert the word "sectional" between "vertical" and "View" Column 5, line 5, change "be" to -the-.

Column 5, line 53, change "assembly" to -assembled-.

Signed and Scaled this Arlest:

RUTH C. MASON Arresting Officer C. MARSHALL DANN Commissioner of Palenrs and Trademarks UNITED STATES PATENT OFFICE PATENT NO,

DATED March 11,

INVENTOR(S) Robert E. Sandorf It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column line Column line Column line Column line "vertical" Column 5, line Column 5, line [SEAL] 51, insert the word "sectional" between and "View".

5, change "be" to -the.

53, change "assembly" to -assembled-.

Evigned and Scaled this thirtieth Day of September1975 A rtesr:

RUTH C. MASON Arresting Officer C. MARSHALL DANN Commissioner of Parents and Trademarks

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
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Classifications
U.S. Classification363/60, 363/146, 363/50, 174/522, 174/541, 361/235
International ClassificationH02M7/10, B05B5/10
Cooperative ClassificationH02M7/106, B05B5/10
European ClassificationH02M7/10B2, B05B5/10