US2779874A

US2779874A - Electronic lock

Info

Publication number: US2779874A
Application number: US190810A
Authority: US
Inventors: Gilbert R Sonbergh
Original assignee: ELECTRO CARD Inc
Current assignee: ELECTRO CARD Inc; ELECTRO-CARD Inc
Priority date: 1950-10-18
Filing date: 1950-10-18
Publication date: 1957-01-29
Anticipated expiration: 1974-01-29

Description

Jan. 29, 1957 R. SONBERGH ELECTRONIC LOCK 2 Shets-Sheet 1 Filed Oct. 18, 1950 W w W m N 9 H 5 4 a U5, EH H my M N H E a W 4 New W W H m a IH HT 7 5 HT L w/M I 3 F 4 w l 2 1 W G m Fir-,

i 11 iw w Jan. 29, 1957 G. R. SONBERGH ELECTRONIC LOCK 2 Sheets-Sheet 2 Filed Oct. 18,- 1950 INVENTOR. G/LBfQT Q. 50/156281! BY a a prmQA/EVS' United States Patent ELECTRONIC LOCK Gilbert R. Sonbergh, Hollywood, Calif., assignor, by mesne assignments, to Electro-Card, Inc, Los Arr-gates,

Califi, a corporation of California Application October 18, 1950, Serial No. 199,81d

4 Claims. (Cl. 250-36) The present invention relates to an improved locking arrangement.

The present invention contemplates the use of a paper or plastic entrance card with metallic areas thereon in predetermined pattern instead of a metal key. The card, in effecting operation of the lock, constitutes a part of either an oscillatory circuit or a non-oscillatory circuit in accordance with the teachings herein.

In general, the invention contemplates the use of a card with metal segments thereon as a part of an electrical network, the network being operable when a proper card is used. A feature of the invention is that the electrical circuit may be adjusted easily to be operated by one of many different types of cards, so that members of a club, lodge or fraternal order may be issued the proper cards periodically depending upon their standing in these organizations.

It is therefore an object of the present invention to provide an improved locking arrangement of this character having the aforementioned features.

A specific object of the present invention is to provide an improved locking arrangement of this character in which an electrical circuit is placed into oscillation upon use of the proper entrance card to effect opening of the lock.

Another specific object of the present invention is to provide an improved locking arrangement of this character which utilizes capacity elements to effect operation of an electrical circuit.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

Figure 1 shows a locking arrangement embodying features of the present invention and utilizing an oscillatory circuit,

Figure 2 shows another arrangement embodying features of the present invention in which a non-oscillatory circuit is utilized,

Figure 3 is a side view in elevation of a card receptacle embodying features of the present invention,

Figure 4 is a partial sectional and partial elevational view taken substantially on the line 4-4 of Figure 3,

Figure 5 is a view taken substantially on the line 5-5 of Figure 3, i

Figure 6, is an enlarged view of a portion of the apparatus shown in Figure 5,

Figure 7 is a perspective view showing an entrance card 'key with portions broken away to show internal arrangement of elements.

in general, the apparatus described herein is adapted to be mounted in the outside front wall adjacent to the entrance of buildings such as private clubs, fraternal lodges and other similar organizations, the apparatus including a slotted portion 2 (Figure 4), for example, two inches long and about Ai-inch wide facing the exterior, into Which club members or other persons having the right to gain admittance to the building or private room may insert the valid card or key. The insertion of such valid key or card results, by means described herein, in actuation of a standard electric door opener or latch release to permit the user to open the door of a building.

Briefly, the card or key 3 (Figure 7) consists of alternating metallic and non-metallic areas in proper spatial arrangement with respect to corresponding metal areas in the lock itself with which they are in juxtaposition but without contacting, to cause an oscillating circuit connected thereto in Figure 1 to change in frequency to, in turn, produce changes in current flow to the oscillatory devices for operating the relay; or to produce the same result using a non-oscillatory circuit of the character shown in Figure 2.

The card receptacle shown in Figures 3-6 containing the conducting segments or areas 1-18 in Figure 2 and 1-24 in Figure 1 may be constructed as shown. The receptacle includes an insulated fixed vertical plate 5:) having mounted thereon such conducting areas. These conducting areas 1-43 may be formed on the insulating plate 56 by various means such as by accurately depositing 1netallic silver paint of high conductivity through a silk screen. These segments or areas 14.3 may be protected from resulting abrasion which may otherwise result by the insertion of entrance cards, by being covered with a releasable sheet of polystyrene 51 having a thickness in the order of .O07-inch. Connections to the contacts Zl-lS may be made by soldering fine wires to the eyelets 52. The card guide strips 53 are bolted against the segment cover sheet 51 by four small machine bolts which also pass through the four tension springs The free ends of the tension springs 54 are cemented, using a solvent such as toluene, to the four blocks 55. These small blocks are in turn cemented to the movable plate 56, the purpose of which is to assert an even pressure against the entrance cards to assure close capacitive coupling of the concealed conducting areas thereon to the silvered segments 1-18 in the receptacle. The tension springs 5'4 are dimensioned so as to hold the movable plate 56 a slight distance away from the silvered segments or contacts 1-18 at all times, even when no entrance card is inserted. This expedient contributes to low electrica losses. The guide strips 53, in conjunction with the tension springs 54 and the movable plate 56 are so dimensioned as to prevent forcible separation of the conducting areas in the entrance cards 3 from the segments 1--8, as for example, by violent bending of the projecting end of the entrance card 3, to thereby prevent operation by a card which has expired and has been switched off. The switch bar 58 is freely pivoted at the point 59, and the motion thus permitted is used to actuate a switch such as a microswitch foil, whereby, for example, plate voltage may be applied to the electron tubes described later only after an entrance card has been fully inserted. This expedient produces increased life of the tubes and makes possible a larger number of combinations, since there is no possibility of erroneous actuation of the lock, as for example, by a negative area in a card passing across positive segments in the receptacle before insertion of the card is complete.

It is noted that the elements 53, 5'4, 55 and 56 are all cemented together to permit their removal as a unit for easy replacement of a worn out cover sheet 51.

The keys used herein for effecting operation of the locks may be prepared in several ways. in one method thin metallic sheets such as aluminum foil 7 and 8 (Figure 7) are cemented on paper 9 or other insuiating material of good dieiectric properties in proper positions to actuate the lock. This paper or other material may then be covered with another sheet 16 cemented on top of the I metallic elements. If the paper is reasonably opaque the metallic elements are thereby concealed and protected from scuffing, wear, etc. The sheet may have various printed matter thereon and the

sheets

9 and 10 may be encased in a transparent plastic envelope which is sealed along all edges.

' A second method of preparing the cards consists in first covering predetermined metal areas of the card with ink, shellac or varnish, then applying powdered metal particles of a low melting point material to the entire surface of the card, then passing the card between an air suction chamber to remove the metal particles from those areas not previously painted. Thereafter, the card is passed through an oven or radiant heat chamber where the powdered metal particles are melted and fused into electrically conducting sheets which adhere to the cards in such predetermined areas.

A third method of preparing a key for types of electronic locks shown herein consists in using a full sheet of metal instead of a card of paper or similar insulating material. Apertures are then punched in the metal sheet in positions corresponding to those segments in the lock which it is desired not to couple capacitively to other segments. Thus. as will be more clear from the following description, an annual key would require apertured portions in juxtaposition with

segments

6, 9, 11, 16, 2t and 24, in Figure l.' With such a key, the

quarterly switches

80, 81 and 82 are, however, preferably connected in series with the anode of tube 61 rather than to ground, because the entire surface of the metal sheet key would be at or near ground potential for radio frequency currents.

Referring to Figure 1, there is shown therein two tunedplate tuned-grid oscillators which include respectively the

tubes

60, 61. These

tubes

60, 61 may be separate sections of a twin triode tube of medium mu or amplification factor. Under normal steady state conditions the oscillation networks associated with

tubes

60, 61 are adjusted so that the plate current is at some value, for example /3 or /2 of the normal average rated plate current for the particular type tube. The grid coils 62 and 63 and the

plate coils

64, 65 are of low inductance and low distributed capacitance, to produce a resultant oscillatory freouency somewhat between 50 and 150 megacycles. The actual frequency of the tuned circuits in the anode circuits is adjusted to be slightly higher than that of the resonant frequency of the grid circuit, in conventional manner for this type of oscillator connection which provides in-phase feedback in producing oscillations. A voltage source 66 has one of its terminals grounded and the other one of its terminals connected to one terminal of the winding 67A of the relay 67, which includes the normally closed switch 67B. The other terminal of the winding 67A is connected both to one terminal of the other relay winding 68A and to the junction point of coil 65 with condenser 70. The other terminal of relay winding 68A i connected to the junction point of coil 64 and condenser 71. The relay 68, having the winding 68A, includes a normally open switch 683. It is thus seen that the space current flowing to the anode of device 60 flows also through the

relay windings

67A and 68A,

while the space current for tube 61 flows only through the relay winding 67A.

Preferably, the source 66 is an alternating current source instead, of a direct current one to make the lock more pick proof. V

The wires labeled To door opener circuit are understood to be connected to a source of current and to a conventional door opener. It will be seen that at any time the relay winding 68A is energized sufliciently to close the switch 683, the dooropener will be energized, provided that the current through winding 67A is of a low enough value so that relay 67 is not operated.

The

condensers

73 and 74, connected respectively in parallel with the coils 62 and 63, are considered optional but are included to provide for a convenient adjustment of frequency of the grid circuit with relationship to the tuning of the associated anode circuits. The condensers 75, connected in parallel with the resistance 76, as well as the condenser 77 connected in parallel with the re sistance 73, form conventional blocking and biasing arrangements for the grids of the

oscillator tubes

60, 61, it being noted that such condenser resistance combinations are connected between the control grid and associated grid coils of corresponding triodes. The plate bypass condensers 70, 71 serve to eifectively ground the cold ends of

coils

64 and 65 and serve to prevent a substantial flow of high frequency currents in the

relay windings

67A and 68A.

It is observed that the anode of device 60 is connected to

metal segments

2, 4 and 8, whereas the anode of device 61 is connected to

metal segments

16, 6, 9 and 11, as well as to segments 20 and 24. The

segments

1, 5, 7, 10 and 12 are grounded. Also grounded are the

segments

14, 17, 18 and 21. The segment 15 is grounded through the switch the segment 19 is grounded through the switch 81, and the segment 23 is grounded through the switch 82.

Operation of the electronic lock is as follows: A valid card or key is inserted as indicated by the arrow and dotted lines so as to be pressed close to the metal segments interconnected as described above. These metal segments are thin sheets and are insulated from each other and from the card or key and form condenser plates. A valid card or key for the lock constitutes conducting metallic elements which form cooperating condenser plates and are sufficiently large to cover simultaneously segments 2 and 1, another to cover the

segments

4 and 5, and a third to cover the

segments

8 and 7.

Segments

2, 4 and 8, which are connected to the anode of tube 60, are therefore capacitively connected to ground when the card or key is inserted. This is equivalent electrically to placing a capacitance across the coil 64, tuning it to a low frequency to thereby tend to cause the feedback through the tube to shift in phase towards a non-oscillating condition. The plate current therefore increases to actuate the normally open relay 68 and thus energize the door opener circuit.

The circuit connected with tube 60, the size of the numbered metal segments, and the distributed capacitance of coil 64, are so designed and adjusted that operation of the normally open relay 68 does not take place unless all of the

segments

2, 4 and 8 are capacitively connected to ground. This prevents or tends to prevent the possibility of picking the look by use of a small metallic element or sheet on the end of a probe inserted into the slot through which the valid card is inserted.

The lock will not be actuated by insertion of a full metallic sheet or any card other than a valid card, because of the fact that covering any one of the

segments

6, 9, 11, 16, 20, 24 together with any other grounded

segments

1, 5, 7, 10, 12, 14, 17, 18 or 21 disturbs the phase relationships in the circuit connected to device 61 sufiiciently to actuate the normally closed relay, thus opening the circuit to the electric door opener. The constants of the circuit connected to tube 61, and particularly the distributed capacitance of coil 65, is so adjusted to provide a greater sensitivity than that obtained solely by the use of tube 60.

The

switches

80, 81 and 82 constitute another new and useful feature of the present invention. In most dues-paying private clubs, some of the members purchase annual memberships and others purchase their privileges on a quarterly or some other short term basis. The members purchasing annual memberships are handed cards or keys of the type previously described. It will be noted that such cards or keys will actuate the lock regardless of the positions of

switches

80, 81 and 82.

Any member purchasing a quarterly membership during the first quarter of the year would be given a card or key similar to the annual card in that it would contain metallic elements arranged to capacitively

couple segments

2, 4 and 8 to ground, but in addition this card would contain a metallic sheet, coating or other element which would couple

segments

16 and 15. This card would function until the date on which the club steward or manager should close the switch 80. With switch 80 closed, the normally closed relay 67 operates due to the increased current in tube 61.

A member purchasing privileges through the second quarter would be given a card with the same elements as the annual card, but including additionally a metallic element to couple segments 20 and 19. This card would cease to function when switch 81 was closed or about June on a quarterly basis.

A card operative through the third quarter would have the same elements to produce oscillations in device 60 to actuate the normally open relay 68 as the other three types of cards described above, but would contain in addition, a metallic element or coating which would serve a to couple segments 24 and 23. When the switch 82 is closed, to thereby ground the segment 23,. on or about September 30 of the calendar year, this card would become inoperative due to the increase in plate current in tube 61.

After September 30, members wishing privileges for the remainder of the year would be given the same cards or keys which are provided annual members at the beginning of the year. To provide a system of exclusion of non-paid members year after year, the wiring of the segments may be changed in proper fashion to make all previously issued cards or keys inoperative, at which time new cards are prepared and distributed.

While the segmented portions of the lock, i. e., the capacity elements, are shown as a set of 24 rectangular metallic sheets or plates, it is to be understood that other sheets could be used such as squares, circles, curved shapes, etc., thus providing a virtually unlimited number of opportunities for difierent and distinct key cards or combinations. Furthermore, while the drawings show, for purposes of simplicity, horizontal pairs of segments capacitively coupled, any other similar arrangement might be used, such as, for example, one which requires that

segments

2 and 18 be coupled but that 2 and 3 or 2 and 1 must not be coupled to allow actuation of the lock. Such methods of wiring segments provide still more possibilities for variations in the key designs or codes.

in Figure 2 a pair of

triode type tubes

30, 31 is used and interconnected with a lock in a non-oscillatory type of circuit which incorporates two series of conducting plates 1-13, both inclusive. There are really two series of such conducting plates, one having odd reference numerals and the other spaced immediately below the first series and having even reference numerals, it being noted that there are nine even numbered plates and nine odd numbered plates. the

tubes

30, 31 in a predetermined manner to impart a specific characteristic type of combination to the lock.

The cathodes of each of the

tubes

30, 31 are interconnected and connected to ground through the resistance 32, the

control grids

34, 35 of

tubes

30, 31 being returned to ground through

resistances

36, 37, respectively.

A relay 39 having a winding 39A and associated relay contacts 39B, is connected between the anodes of tubes 33, 31. Condenser 39C is connected in parallel with the winding 39A. The relay winding 39A, when energized with current above a predetermined magnitude effects closure of the switch 39B. The switch 39B is interconnected with a conventional solenoid operated door lock such that closure of the switch 39B causes the associated door to be unlocked. The anode 40 of device 31 is returned to its cathode through resistance 41. Space current for the

devices

30, 31 is supplied from the These are interconnected with voltage source 42 which may either be unidirectional or alternating in character; and if unidirectional, the positive terminal of source 42 is connected to the anode 40 through switch 60 while the negative terminal of source 42 is grounded.

An alternating current voltage source 44 has one of its terminals grounded and the other one of its terminals connected to one terminal of resistance 46, the other terminal of resistance 46 being shown connected to both segments 1 and 10. The control grid 35 is connected to

segments

3, 7, 9, 13, 15 and 17, as well as to

segments

2, 6, 8, 14 and 16. The control grid 34 is connected to

segments

5 and 11. The

segments

4 and 10 are interconnected through switch 47; the

segments

10 and 12 are interconnected through switch 48, and the

segments

10 and 18 are interconnected through switch 49.

The

tubes

30, 31 may be the triode sections of a twin triode medium mu type such as the 12AU7.

The operation of the circuit is such that when the anode current in tube 30 is in the order of 9 to 10 milliamperes the relay 39 is operated to cause the associated door to be opened, upon association of a proper card with the contacts 1-18, both inclusive. However, if an improper or expired card is used, i. e., associated with the,

contacts 1-18, both inclusive, the anode current for tube 31 increases to a magnitude of, for example, 7 to 10 milliamperes to therebyproduce an increased voltage drop across the cathode bias resistance 32 which is common to both

tubes

30 and 31. This resulting increased grid bias on tube 30 prevents tube 30 from drawing suiiicient current to actuate the relay.

The switch is a microswitch actuated by the inserted card, as shown in Figure 3. When switch 160 is closed it is noted that the source 42 is connected across the voltage divider comprising the

resistances

41 and 32. The values of

resistances

41 and 32 are such that with the switch 160 closed, both

tubes

30 and 31 are biased nearly to cut-off, assuming, of course, there is no other voltage applied to the

control grids

34 and 35.

The resistance 46 is of high value in the order of l megohm and is used for protective purposes in case one inserts a metal object, as for example, an ice pick, into the receptacle in which the contacts 1-18 are disposed. The condenser 390 is in the order of 2 to 8 microfarads and is used for filtering purposes and to prevent chattering of the associated relay.

The circuit shown in Figure 2 is such that a capacitive connection must exist between two pairs of segments or contacts to achieve operation. These two pairs in Figure 2 correspond to contacts 1 and 5, on the one hand, and 10 and 11, on the other hand. In such case the key card has two conducting areas, one of such areas being in juxtaposition with contacts 1 and 5 and the other conducting area being in juxtaposition with

contacts

10 and 11, so as to provide suliicient capacity coupling between source 44 and the control grid of tube 34, to thereby cause actuation of switch 393. However, in the event that the card is an improper card and contains additional conducting areas such as, for example, a conducting area in juxtaposition with

segments

8 and 10, or, for example, with segments 1 and 3, then there is suificient capacity coupling between source 44 and the control grid of tube 31 to produce a relatively large flow of current through the biasing resistance 32 to prevent a sufficient current fiow through the relay winding 39A.

The

switches

47, 48 and 49 are utilized to invalidate certain cards, after, for example, a month or any other established time.

In order that the card may expire or become inoperative when the first switch 47 is closed, the card contains a graphite coating or conducting area in juxtaposition with and serving to couple contacts 4 and 6. In such case when switch 47 is closed, the source 44 is coupled to the control grid of tube 31 to cause sufiicient current to flow through the biasing resistance 32 and to thereby prevent the flow of sufiicie'nt current through tube 30 and relay winding 39A. 'A card supposed toexpire or become inoperative when switch 48 is closed incorporates means in the form of a conducting area which is in juxtaposition with and serves to couple

contacts

12 and 14 in addition to the two positive pairs 1 and 5 on the one hand and 10 and 11 on the other hand. A card supposed to expire or become inoperative when the third switch 49 is closed contains a conducting coating which is in juxtaposition with and'serves to couple

contacts

16 and 18.

While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim inthe ap'- pended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

1. In a locking arrangement of the character described, a lock element having a plurality of conducting segments insulated from each other, a key having a plurality of conducting segments insulated from each other and from the first mentioned segments, certain of the key and lock conducting segments formingelectrical condensers, an

electrical circuit connected with said condensers, means coupled'to said circuit and operated upon establishment of said condensers, means rendering the last mentioned means inoperative upon capacitively-coupling certain ad-' ditional ones of said lock conducting segments together,-

ditional conducting segments. a

2. The arrangement set forth in claim 1 in which said electrical circuit includes an oscillatory circuit which is connected to said condenser elements and is tuned to suband switches connected to interconnect said-certain adtantially resonant frequency of said oscillatory circuit'by said condenserelements upon cooperation of said lock conducting segments with said key conducting segments to operate said first means.

' 3'. The arrangement set forth in claim 1 in which said electrical circuit includes an electron discharge device normallytbiased to produce a relatively small current fiow therethrough, and said circuit incorporating means for increasing the bias on said electron discharge device upon cooperation of theconducting segments on said key with the conducting segments in said lock. 7

4. The arrangement set forth in claim 1 in which said lock element includes arelatively stationary plate having said conducting segments thereon, a wear plate of insulating material covering said conducting segments and mounted on said plate, a spring biased pressure plate spaced from .said ,wear plate and defining a space into which said key in the form of a card may be inserted with the pressure plate pressing the card against said wear plate.

Referenees Cited in the file of this patent UNITED STATES PATENTS 1,838,084 Drake v Dec. 29, 1931v 2,094,351 Draper et al. Sept. 28, 1937 2,150,440 Hargreaves Mar. 14, 1939 2,244,023 Sauer June 3, 1941 2,245,388, Conron June 10, 1941 2,275,590 Johnson Mar. 10, 1942 2,468,574 Russnak Apr. 26, 1949 2,566,017 Cooley Aug. 28, 1951 2,581,680 Martenot Jan. 8, 1952 FOREIGN PATENTS 170,582 Great Britain Apr. '27, 1922