US3160792A

US3160792A - Electric lock

Info

Publication number: US3160792A
Application number: US10721A
Authority: US
Inventors: Roger C Brendemuehl; Leslie H Gerhardt; Joseph B Kripke
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1960-02-24
Filing date: 1960-02-24
Publication date: 1964-12-08
Anticipated expiration: 1981-12-08

Description

United States Patent 3,160,792 ELECTRIC LOCK Roger C. Brendeinuehi, Leslie H. Gerhardt, and Joseph B. Kriplre, Milwaukee, Wis, assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Feb. 24, 1960, Ser. No. 10,721 Claims. (Cl. 317-134) This invention pertains to locking devices, and particularly to an improved electric locking arrangement.

At the present time the majority of locking devices are of the multiple tumbler type requiring a mechanical key for opening the same. Inasmuch as locks, of necessity, must be of reasonable size, the number of tumblers which can be embodied in a lock are limited, and accordingly the number of different combinations are likewise limited. The present invention relates to an electric lock which, while comparable in size to conventional tumbler locks, has a substantially greater number of available combinations. Accordingly, among our objects are the provision of an electric lock of simplified design and construction; an electric lock having a large number of available combinations utilizing a standard circuit board; the further provision of an electric locking circuit including a plurality of series switches and a plu rality of parallel switches; and the still further provision of a key for opening an electric lock of the aforesaid type.

The aforementioned and other objects are accompiished in the present invention by constructing the key to close the series switches and open the parallel switches of the locking circuit. Specifically, the locking circuit includes a lock actuating solenoid, which when energized, permits the device with which the lock is associated to be operated in its intended manner. The locking circuit also includes a thwart relay which, when energized, open circuits the lock solenoid circuit. Moreover, if desired, the locking circuit may include an alarm which will be energized if a wrong key is inserted into the lock. The lock, per se, comprises a receptacle having a circuit board and a keyway with a plurality of leaf spring contacts disposed on opposite sides of the keyway. The leaf spring contacts are electrically connected to a printed or etched circuit on the circuit board. In the instant lock, a single circuit board can be used for all of the available combinations thereby greatly simplifying the manufacturing technique. The individual circuit board combinations are made by disconnecting certain conductors from other conductors on each board which can be done by drilling through the etched or printed circuits.

The key may be composed of insulating material, or metal, having a plurality of pins projecting from both sides thereof. Externally, it cannot be determined whether the pins extend through the key or not. The keys are coded by extending some of the pins through the key body to form connected contact pairs and separating other of the pins by an insulator in the key body to form disconnected contact pairs. The through pins are used to close the series switches, and the open pins are used to open circuit the parallel switches.

Since it is desirable to have all of the keys fully insorted in the receptacle to energize the circuit, either of the two end contact pairs must close a series switch. Accordingly, there are three different combinations of the first two contact pairs, namely contact pair one closed, contact pair two open; contact pair two closed, contact pair one open; and contact pairs one and two closed. The remaining switches may be either open or closed, so that there are two different combinations for each switch. A typical key of standard size can conveniently carry sixteen pairs of contacts so that with this type of lock there is a possibility of 49,151 useful combinations.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodiment is clearly shown, and wherein similar numerals depict similar parts throughout the sev eral views.

In the drawings:

FIGURE 1 is a transverse sectional view of a typical key receptacle.

FIGURE 2 is a plan view of a typical circuit board.

FIGURE 3 is a fragmentary view in elevation of a typical key.

FEGURE 4 is a perspective view of one of the leaf spring contacts used in the receptacle.

FIGURE 5 is a diagram of the locking circuit.

With particular reference to FIGURE 1, the lock includes a receptacle 1% comprising a housing 12 of insulatin material having a keyway 14, and a circuit board 16 suitably attached to one side of the housing 12. The circuit board includes a base of insulating material, and has a circuit 18, either etched or printed on one side. The keyway 14 has a longitudinally extending tongue 26 extending thereinto, the tongue 29 being adapted for reception in a longitudinally extending groove 22 of a key 24 for guiding and properly aligning the key within the keyway 14.

With reference to FIGURE 2, the printed or etched circuit 18 on the circuit board 16 comprises one longitudinaliy extending conductor 26, four longitudinally extending buss bar conductors 2%, 3t 32. and 34, and thirty-five transversely extending

conductors

36, 38, etc., through 194. Each of the transverse conductors 42 through 104 has a ieaf spring contact electrically connected thereto, 42a, 44a, etc, through 1164a. The transverse conductors are arranged in two rows, as depicted in FIGURE 2. The ends of conductors 42 through 72 are connected in parallel between buss bars 28 and 3'9, with the ends of conductors 74- through 104 connected in parallel between buss bars 32 and 34-.

A typical leaf spring contact is shown in FIGURE 4, and comprises a terminal portion 1%, which is electrically connected to its respective conductor in the circuit board 16, and a contact portion Hi3. As seen particularly in FIGURE 1, the contact portions of the leaf spring con tacts are disposed in the keyway 14 in four rows, two rows on each side of the keyway. Each row includes eight contacts so that the receptacle 12 contains thirtytwo leaf spring contacts. The contacts are preformed as depicted in FIGURE 4- and suitably held in position in a mold while the housing 12 is molded therearound so that the contacts are integrally supported within the housing.

As alluded to hereinbefore, the same circuit board can be used for all locks. In order to code the locks, individual circuit combinations are made by disconnecting certain conductors from each other and/ or form the buss bars and this can be accomplished by drilling through the conductor and/ or buss bar and board as depicted by the holes in FIGURE 3. The

conductors

26, 36, 38, 4t) and 42 have

terminals

26b, 36b, 38b, 40b and 42b electrically connected thereto. The terminals 38b and 4012 are connected by suitable wires to opposite sides of a solenoid operated lock actuating means. In addition, in the specified circuit board depicted in FIGURE 2 the conductors 52 and 56 have terminals 52b and 56b electrically connected thereto, which terminals are connected by

external wires

112 and 114 respectively, to terminals 38b and 46b, respectively. The terminals 26b and 4212 are connected to a power source, and the terminal 36b is connected to thwart means to be described.

With reference to FIGURE 3, the key 24 may have either a metal key body or a plastic insulator body. However, as shown, the key 24 includes a metallic body. The keyway has rows of spaced pins located on opposite sides of the slot, or groove, 22. Each row comprises eight pins, so that the key includes sixteen

pins

116, 118, etc., through 146. Each of the pins 116 through 146 constitutes a pair of contacts which are engageable with a pair of the contacts 42a through 1114a carried by the receptacie 12. All of the pins 116 through 146 have the same exterior appearance on the key 24. However, as seen in FIGURE 1, some of the pins extend through the key body, while other of the pins are spaced apart by an insulator, whereby coding the key for a particular coded circuit board.

When the body of the key 24 is metallic, pins 116 through 146 are mounted in strips of plastic

insulating material

148 and 150. The pin shown in the upper strip 143 in FIGURE 1 is separated by a portion of the insulator strip 143 and is thus nonconductive. The pin depicted in the lower strip 158 in FIGURE 1 is continuous and is therefore conductive. Consequently, the switch constituted by the leaf spring contacts in engagement with the lower pin in FIGURE 1, is closed, while the switch constituted by the leaf spring contacts associated with the upper pin in the key in FIGURE 1, is open.

As alluded to hereinbefore, a properly coded key is constructed to close series switches and open parallel switches when inserted in a receptacle having a circuit of the same code. With reference to FIGURE 5, a typical circuit will be described. A battery 15?. has one terminal connected to ground and the other terminal connected through a thermal overload circuit breaker 154 to a wire 156. The wire 156 is connected to terminal 425 of the circuit board 16. The circuit board 16 depicted schematically in FIGURE is coded like the circuit board shown in FIGURE 2. Accordingly, the series switches which must be closed to energize the lock actuating means include contact pins 116, 132, 118, 136, 138, 126, 128 and 144. When the key is fully inserted, contact pin 116

bridges contacts

42a and 74a, contact pin bridges contacts 44a and 76a; contact pin 118

bridges contacts

46a and 78a; contact pin 13dbridges contacts 48a and 80a; contact pin 120 bridges contacts 50a and 82a; contact pin 136 bridges contacts 52:: and 84m; contact pin 122 bridges contacts 54a and Sea; contact pin 138 bridges contacts 564: and 88a; contact pin 124 bridges contacts 58a and 99a; contact pin 14!) bridges contacts 611a and 12a; contact pin 126 bridges contacts 62a and 94a; contact pin 14-2 bridges contacts 64!: and 95a; contact pin 12 5

bridges contacts

66a and 98a; contact pin 144

bridges contacts

68a and 100a; contact pin 13% bridges contacts 743a and 102a; and contact pin 146

bridges contacts

72a and 104a. In the specifically disclosed locking circuit, pins 120, 122, 12 i, 1341, 134 141i, 142 and 146 are nonconductive so as to open the parallel switches. A lock solenoid 158, constituting the lock actuating means, is con nected between terminals 38!: and 41111, and a thwart relay 160 is connected between terminals 361) and 26b. The thwart relay 160, when energized, opens a switch 162 which open-circuits the the lock solenoid S irrespective of closure of the series switches.

The circuit depicted in FIGURE 5 also includes an alarm system comprising a vehicle horn 164. The horn is controlled by a horn relay 166, one terminal of which is connected to ground and the other terminal of which is connected to the conductor 319 by wire 16%. The horn relay 166, of course, can be actuated manually by a horn switch 170 which completes the circuit to the horn relay through wire 172.

When a properly coded key is inserted into the receptacle 10 having the circuit board 16 depicted in FIGURE 2 and schematically depicted in FIGURE 5, the series switches comprised by

key pins

116, 132, 118, 136, 138, 126, 128 and 144 will connect the lock solenoid 158 to opposite sides of the battery 152 thereby energizing the same. All of the parallel switches formed by

contact pins

13 i, 120, 122, 124, 140, 142, 130 and 146 remain open so that the thwart relay 160 is deenergized as is the alarm circuit. In order to prevent energization of the lock solenoid 158 by supplying power to only one terminal of the lock solenoid, the series switches are arranged on both the power and ground sides of the lock solenoid.

The circuit breaker 154 is included in the locking circuit to deenergize the circuit, if an all metal key is inserted in the receptacle, which metal key would short circuit the battery 152. With the key receptacle designed as shown and described, the locking circuit cannot be energized until the key is fully inserted in the receptacle. Accordingly, either of the two end switches formed by the contact pins 116 and 132 on the key must be closed. Accordingly, there is a possibility of three different switch combinations of the contact pins 116 and 132. The remaining switches may be either open or closed, thus giving two combinations for each switch. Since the circuit board disclosed has a total of sixteen switches the total number of combinations would be the product of 3 2 However, since one of these combinations would have all of the remaining switches open, there are c-niy (3 2 )1 useable combinations. This is true since at least two switches should be used in series with the lock solenoid to prevent picking of the lock. Thus, with a sixteen switch circuit board such as disclosed, there would be 49,151 useful combinations. If an improperly coded key is inserted into the receptacle, the lock solenoid 158 will not be energized. Moreover, in some instances it may energize the alarm 164 by closing one of the parallel switches.

While the embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. An electric lock including, a receptacle having a keyway and a plurality of spaced stationary switch contacts insulated from each other and extending into said keyway, said contacts being arranged in aligned pairs with one contact of each pair being on opposite sides of said keyway, a circuit board having a conductor electrically connected to each receptacle carried contact, said conductors being coded by selective electrical interconnection of at least some of said conductors with other of said conductors on said board to form an unlocking circuit, and a key insertable into said keyway and having a plurality of spaced switch contacts insulated from each other, the number of key carried contacts being equal to the number of receptacle carried contacts, half of said key carried contacts being located on each face of said key so that each key carried contact is engageable with a receptacle carried contact, said key carried contacts being coded by selective electrical interconnection of at least some of said key carried contacts with other of said key carried contacts so that only a properly coded key will complete the unlocking circuit when inserted into the keyway of said receptacle.

2. An electric lock including a receptacle having a keyway and a plurality of spaced stationary switch contacts insulated from each other and extending into said keyway, said contacts being arranged in aligned pairs with one contact of each pair being on opposite sides of said keyway, a circuit board having a conductor electrically connected to each receptacle carried contact, said conductors being coded by selective electrical interconnection of at least some of said conductors with other of said conductors on said board to form an unlocking circuit, and a key insertable into said keyway and having a plurality of spaced switch contacts insulated from each other, the number of key carried contacts being equal to the num ber of receptacle carried contacts, half of said key carried contacts being located on each face of said key so that each key carried contact is engageable with a receptacle carried contact, said key carried contacts being coded by selective electrical interconnection of at least some of the key carried contacts on opposite faces of the key to form bridging means engageable with the pairs of receptacle carried contacts on opposite sides of said keyway so that only a properly coded key will complete the unlocking circuit when inserted into the keyway of said receptacle.

3. The electric lock set forth in claim 2 wherein said receptacle carried switch contacts comprise leaf springs.

4. The electric lock set forth in claim 2 wherein said circuit board is composed of insulating material having conductors thereon.

5. The electric lock set forth in claim 4- wherein at least some of the conductors on said board are disconnected from other conductors by holes through said board and the conductors.

6. The electric lock set forth in claim 2 wherein said key carried contacts comprise pins, at least some of which extend through said key to form electrically interconnected pairs of contacts and others of which are insulated from each other to form insulated pairs of contacts.

7. An electric locking arrangement including, actuating means movable between lock open position when energized and lock closed position when deenergized, a source of power for energizing said lock actuating means, at least one switch connected in series between one side of said power source and one side of said lock actuating means, at least one switch connected in series between the other side of said power source and the other side of said lock actuating means, coded switch operating key means for closing said series switches to energize said lock actuating means, and thwart means connected in circuit with said lock actuating means, said thwart means, when actuated, precluding energization of said lock actuating means irrespective of the closure of said series switches.

8. An electric locking arrangement including, lock actuating means movable between lock open position when energized and lock closed position when deenergized, a source of power for energizing said lock actuating means, at least one switch connected in series between one side of said power source and one side of said lock actuating means, at least one switch connected in series between the other side of said power source and the other side of said lock actuating means, coded switch operating key means for closing said series switches to energize said lock actuating means, thwart means connected in circuit with said lock actuating means, said thwart means, when actuated, precluding energization of said loclr actuating means irrespective of the closure of said series switches, thwart actuating means, and at least one switch connected in parallel with said series switches between said power source and said thwart actuating means and closable by an improperly coded switch operating key means for energizing said thwart actuating means.

9. An electric locking arrangement including, lock actuating means movable between lock open position when energized and lock closed position when deenergized, a source of power for energizing said lock actuating means, a plurality of series switches connected between said lock actuating means and said power source, thwart means connected in circuit with said lock actuating means, thwart actuating means, a plurality of parallel switches connected in parallel with said plurality of series switches between said thwart actuating means and said power source, and coded switch operating key means for closing said series switches and opening said parallel switches to energize said lock actuating means. 1

10. The electric locking arrangement set forth in claim 9 wherein said thwart means comprises a switch connected in series with said lock actuating means and wherein said thwart actuating means comprises a relay for operating said switch, said relay being connected to said power source upon closure of any one of said plurality of parallel switches.

Reterenc s fitted in the file of this patent UNITED STATES PATENTS 1,393,822 Parker Oct. 18, 1921 1,695,518 Watson Dec. 18, 1928 2,436,809 Joel Mar. 2, 1948 2,473,664 Taylor June 21, 1949 2,613,252 Heibel Oct. 7, 1952 2,985,709 Mammola May 23, 1961

Claims

7. AN ELECTRIC LOCKING ARRANGEMENT INCLUDING, ACTUATING MEANS MOVABLE BETWEEN LOCK OPEN POSITION WHEN ENERGIZED AND LOCK CLOSED POSITION WHEN DEENERGIZED, A SOURCE OF POWER FOR ENERGIZING SAID LOCK ACTUATING MEANS, AT LEAST ONE SWITCH CONNECTED IN SERIES BETWEEN ONE SIDE OF SAID POWER SOURCE AND ONE SIDE OF SAID LOCK ACTUATING MEANS, AT LEAST ONE SWITCH CONNECTED IN SERIES BETWEEN THE OTHER SIDE OF SAID POWER SOURCE AND THE OTHER SIDE OF SAID LOCK ACTUATING MEANS, CODED SWITCH OPERATING KEY MEANS FOR CLOSING SAID SERIES SWITCHES TO ENERGIZE SAID LOCK ACTUATING MEANS, THWART MEANS CONNECTED IN CIRCUIT WITH SAID LOCK ACTUATING MEANS, SAID THWART MEANS, WHEN ACTUATED, PRECLUDING ENERGIZATION OF SAID LOCK ACTUATING MEANS IRRESPECTIVE OF THE CLOSURE OF SAID SERIES SWITCHES.