US3475932A - Combination lock - Google Patents

Description

Nov. 4, 1969 c. E. GERMANTON I 3,475,932

cousxm'rzoupocx Filed March 2 1967 4 Sheets-Sheet 1 INVENTOR C. E GERMANTON By @m v ATTORNEY Nqv. 4, 1969 c. E. GERMANTON COMBINATION LOCK 4 Sheets-Sheet 2 Filed March 28, 1967 Nov. 4, 1969 c, 5. GERMANTON 3,475,932

COMBINATION LOCK Filed March 28, 1967 4 Sheets-Sheet 3 FIG. 88 I I CAP 45 cmca KNOB I8 RETURN DISSIPATED S0 STARTED CANNOT BE USED I? II II EELAY KNOB I8 RETURN CONTINUED; I I CA N BE RELEASED INTERPOSER 29 DEI-LECTED TO ONLY BY. SECMD ENGAGE RADIAL ARM 2| SO ARM COMBINATION MOVES WITH KNOB I6, LATCH RETRACTED AND ENTRANCE v v GAINED 1 KNOB I8 RELEASED; SPRING 22 RETURNS RADIAL ARM 2| AND ON KNOB IS IN ENGAGING SPRING 3| RELEASES RELEASED STATE INTERPOSE R 29', VANE 24 AND RADIAL ARM 2| RETURN TO *6 AND H NORMAL POSITIONS CAP 48 CHARGES ATTEMPT ABANDONED CAP 42 RECHARGES KEY T TART AGAIN STATE OF DEVICE NORMAL STATE OF DEVICE GIIANGED SPOT SET OF CONTACTS United States Patent 3,475,932 COMBINATION LOCK Charles E. Germanton, Summit, N..I., assignor to Bell Telephone Laboratories, Incorporated, Murray Hill, N ..I., a corporation of New York Filed Mar. 28, 1967, Ser. No. 626,566 Int. Cl. 1365b 49/02, 47/02 US. Cl. 70-278 6 Claims ABSTRACT OF THE DISCLOSURE The outer knob of a door is interlocked with an unlatching member by deflecting an interposer member. Electrical circuitry is provided to effect deflection of the interposer member when a predetermined combination of operative steps is followed and to prevent deflection of the interposer member when a combination of steps other than the predetermined one is followed.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to combination locks utilizing electric circuitry.

Description of the prior art Combination locks provide several advantages over key-operated locks. With a combination lock, for example, an authorized person need not be concerned with a key which may be forgotten or lost. Furthermore, access by an unauthorized person who has found or stolen a key is eliminated. Still further, combination locks are frequently more pick-proof than key-operated locks.

Notwithstanding the above advantages, combination locks have not received as widespread use as key-operated locks. This limited use exists for one or more reasons. Many combination locks, for example, are not sufficiently pick-proof. Furthermore, it is often diflicult or impossible to change their opening combinations so as to foil persons no longer authorized. Still further, the costs of reliable combination locks are often prohibitive.

SUMMARY OF THE INVENTION An object of the present invention is to provide one or more of the following features in a combination lock:

(1) To make the lock substantially pick-proof in the sense that almost any combination other than its opening combination renders the lock nonresponsive to subsequent applications of the opening combination until a reactivating step has been taken;

(2) Once the lock has become nonresponsive to its opening combination, to be able to reactivate it by using a second combination;

(3) To produce an indication when someone is attempting entry or when the lock has been rendered nonresponsive to its opening combination;

(4) T o be able to quickly and easily change the opening and reactivating combinations;

(5) To be able to use the lock in a door latching arrangement which is easily installed and removed;

(6) To require relatively little electrical energy; and

(7) To require relatively little maintenance.

This and other objects are achieved by the invention in an electromechanical arrangement that requires particular buttons in a set of pushbuttons and a knob or handle to be operated in a combinational sequence in order for the lock to be opened. In particular, pushbuttons are first operated to close an electrical circuit. Closure of this circuit causes a first mechanical member to move so that ice a second mechanical member may move past it when the knob is turned. The knob is then turned. After it has been turned, other pushbuttons are operated to close another electrical circuit. Closure of this circuit causes the first member to return to its original position. The knob is then returned to its original position. In the course of returning the knob to its original position, a cam-like action between the first and second members causes the second member to interlock the knob with the latching element of the lock, thus causing a latching element to be released by the returning knob.

In accordance with the invention, initial movement of the first member is produced by transferring stored energy from a first capacitor to a second capacitor. The final movement of the first member is produced by transferring stored energy from the second capacitor back to the first capacitor. When, however, an incorrect combination is followed, the initial movement of the first member occurs but the stored energy is dissipated so that its return movement cannot occur. Because the return movement cannot occur, the cam-like action cannot be produced and the latching element is not released by the returning latch or knob.

Another feature of the invention permits charge dissipated by following an incorrect combination to be replaced by the execution of a reactivating combination. The lock may then be opened by the opening combination.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a portion of a door containing a lock embodying the invention;

FIGS. 2 through 5 and FIGS. 6A through 6E are sectional views showing various elements of the door lock;

FIG. 7 is a schematic diagram of the circuit employed in the door lock;

FIGS. 8A and 8B are portions of a sequence chart illustrating various steps that may be performed and the results produced thereby when attempting to open the lock; and

FIG. 8C is a diagram showing how FIGS. 8A and 8B should be arranged.

DESCRIPTION OF THE DISCLOSED EMBODIMENT FIG. 1 shows a portion of a door 11 in which is mounted a combination door lock assembly 12 that embodies the invention. The locked side or outside of door 11 faces the viewer in FIG. 1.

The sectional view of lock assembly 12 shown in FIG. 2 is viewed looking up into the assembly from the side of the door shown in FIG. 1. The sectional view shown in FIG. 3 is viewed looking up into the assembly from the other side (that is, the inside) of the door. All of the elements in FIGS. 2 and 3 are in their normal positions.

The assembly comprises an outside plate 13, an inside plate 14 and a pair of end plates, only one of which is shown and is identified by the symbol 15. A shaft 16 and a shaft 17 are mounted in plates 13 and 14, respectively. An outer knob 18 is mounted on shaft 16 while an inner knob 19 is mounted on shaft 17. Also mounted on shaft 17 is a latch tripping arm 20. When mounted in the door, as shown in FIG. 1, this arm trips the latch to rous vane 24 is mounted on shaft 16 and is spring loaded by a spring 25 so its normal position is against a stop 26 mounted on plate 14. A stop 27 is mounted on palte 13 to limit the degree of rotation of vane 24.

Vane 24 includes a flange 28 having an L shaped aperture cut therein. An interposer member 29 is also mounted on shaft 16 and extends through the aperture in flange 28. A small stop 30 is mounted on vane 24 (see FIG. 3) so as to give support to interposer member 29 in a manner which will become apparent.

A spring 31 is secured to plate 14 in such a manner that its sloping leading edge forces interposer member 29 toward outer knob 18 when the member is in its position closest to knob 19 and knob 18 is turned counter clockwise. On the other hand, when knob 18 is in its extreme counter clockwise position and the member is in its position closest to knob 19, interposer member 29 merely deflects the spring radially as knob 18 is turned clockwise with the result that interposer member 29 is not displaced with respect to flange 28.

The lock assembly also includes a relay 32 (not shown in the fragmentary view of FIG. 3) mounted on plate 14. This relay is of the magnetically latching type whereby a current pulse in a first direction causes the relay to operate and remain operated and a current pulse in the opposite direction causes the relay to release. An extension arm 33 is connected to the relay armature. This extension arm has a tapered end which will be discussed subsequently with respect to the operation of the lock.

A first magnet 34 and a first reed switch 35 are mounted close to stop 26 so that vane 24 passes between the magnet and the switch when the vane is held against stop 26. When the vane is between the switch and the magnet, the switch is in an open, that is disabled, state because the magnetic flux cannot pass through the switch. On the other hand, when the va'ne is moved from between the switch and the magnet, the magnetic flux passes through the switch and causes the switch to close. A similar combination comprising a magnet 36 and a reed switch 37 are mounted close to stop 27 so that vane 24 passes between them when the vane is held against stop 27.

Mounted on panel 13 is a container 38 which includes all of the locks circuitry with the exception of relay 32 and switches 35 and 37. Container 38 includes a plurality of pushbutton-operated switch assemblies which protrude through panel 13 and are generally identified by the symbol 39.

Before discussing the electrical circuitry of the lock assembly the functions of the above-identified mechanical members are first presented.

As mentioned above, all of the mechanical elements are shown in their normal positions in FIGS. 2 and 3 and, furthermore, the door may be unlatched by turning inner knob 19. The door can not, however, be unlatched by merely turning knob 18. In particular, as knob 18 is turned, interposer member 29 passes spring 31 and switch 35 closes. As will be explained subsequently, the closing of switch 35 causes relay 32 to operate. If relay 32 were not operated, interposer member 29 would encounter relay armature extension arm 33 and would be deflected as shown in FIG. 6A. Relay 32 remains operated and, as shown in FIG. 6C, knob 18, when released, returns to its normal position without causing latch tripping arm 20 td'be moved.

In order to move latch tripping arm 20, relay 32 must first be operated so that interposer member 29 may be moved past extension arm 33 when knob 18 is turned. The manner in which interposer member 29 passes arm 33 is demonstrated in FIGS. 6B and 6C. Once this is accomplished, relay 32 must be released as shown in FIG. 6D. When knob 18 is turned back to its original position, interposer member 29 moves toward plate 14 as the member rides up on the sloping portion of extension arm 33. This is shown in FIGS. 4 and 6E. It should be noted that at this point that interposer member 29 is on the other side of radial arm 21 and, furthermore, has been moved so that when knob 18 is returned, the interposer member comes into contact with the radial arm and causes it to rotate with the interposer member. Stop 30 supports the interposer member so that it is not unduly deflected in the process of exerting a force on the radial arm. As knob 18 returns to its normal position, spring 31 deflects and permits interposer member 29 to pass with the radial arm. Moving the radial arm, of course, rotates shaft 17 which moves latch tripping arm 20 to unlock the door.

When knob 18 is released, spring 22, which is stronger than spring 25, causes shafts 16 and 17 to rotate in a direction to return radial arm 21 to its normal position. While this is occurring, the sloping front of spring 31 deflects interposer member 29 which, in turn, moves out of physical contact with radial arm 21. Springs 22 and 25 then cause their respective shafts to return to their normal positions. The door has thus been unlocked and the lock has been returned to its initial state.

The electrical circuit in container 38 and the manner in which it is used to operate and release relay 32 is now presented in conjunction with FIG. 7.

For convenience in the following discussion, pushbutton assemblies 39 of FIG. 2 are identified by the letters A through H and J, respectively. In the disclosed embodiment, these assemblies are of the type that are easily inserted and removed a panel. The opening and reactivating combinations are therefore easily changed by merely rearranging the locations of the assemblies; that is, rewiring is not necessary in order to change the combinations.

In FIG. 7, an X on a conductor implies a normally open set of contacts while a short perpendicular line through a conductor implies a normally closed set of contacts. This is illustrated in the key in FIG. 7. The letters A through H and J adjacent to the contact symbols refer to the pushbutton assemblies on which these contacts are located. The presence of a number next to a set of contacts implies that more than one set of contacts are on a pushbutton assembly. Contacts K are contacts on relay 32 while contacts K and K are contacts in limit switches 35 and 37, respectively.

For the lock to open in response to its opening combination, all of the contacts of FIG. 7 must initially be in the states shown. Under these conditions, a conducting path comprising a resistor 40, contacts K and K and relay 32 exists between a battery 41 and a capacitor 42. As a result of this path and battery 41, a charge is stored on capacitor 42 so that its ungrounded terminal is negative with respect to ground. (Resistor 40 limits the charging current so that relay 32 is not operated.)

Further study of FIG. 7 shows a path including a pair of single-pole double-throw switches which comprise contacts A and B on pushbutton assemblies A and B. The normally open portions of these switches are connected in series in this path with their common contacts (that is, their swinger or arm contacts) connected together and their remaining contacts grounded. When the opening combination is followed, contacts A are operated and held, contacts B are operated and held and a portion of the energy in capacitor 42 passes through relay 32 to capacitor 45. Relay 32 operates and remains magnetically latched in an operated position. Contacts A are then released and capacitor 42 discharges its remaining energy to ground. Contacts B are then released to remove ground from relay 32.

FIG. 7 shows another path which includes a similarly connected pair of single-pole double-throw switches which comprise contacts C and D of pushbutton assemblies C and D. When the opening combination is followed, this path operates in the same manner as the path described in the previous paragraph and relay 32 is released.

When a wrong combination is used, one of the paths described in the two previous paragraphs or one of several other paths functions in a manner to discharge capacitors 42 and 45 and to leave relay 32 in an operated state. The manner in which these various paths function is now presented in detail.

The manner in which the disclosed embodiment responds to various combinations is described below with the help of the sequence chart shown in FIGS. 8A and 8B. This chart is read from top to bottom. The broken vertical line on the left shows the actions produced on a step-by-step basis when the opening combination is followed. The lines to the right of this line show the various actions produced when deviations from the opening combination are made. In reading the chart, a dot at the bottom of a vertical line segment means that it is possible for the action to progress from that line segment into any of the other line segments surrounding the dot. On the other hand, a dot at the top of a vertical line segment means that action on any of the other line segments surrounding that dot will progress into the vertical line segment. Furthermore, as indicated in the key, an X indicates a device is operated while a perpendicular bar indicates the device is released.

The combination for opening the lock assembly and the results produced thereby comprise (see FIGS. 7, 8A and 8B):

(1) Depressing, and holding depressed, the button of assembly A: When an optional alarm circuit 43 is present, contacts A cause this alarm to be sounded as an alert that someone (either authorized or unauthorized) is attempting entry;

(2) Depressing, and holding depressed, the button of assembly B: A path is completed from capacitor 42, through relay 32, contacts K B and A a resistor 44 to a capacitor 45. The charge on capacitor 42 is divided between capacitors 42 and 45. The resulting current flow operates relay 32 which, in turn, opens the path between battery 41 and capacitors 42 and 45 and moves extension arm 33. Relay 32 remains magnetically latched in its operated state.

(3) Releasing button of assembly A: A path from capacitor 42, relay 32 and contacts K B and A to ground is completed and capacitor 42 is discharged.

(4) Releasing button of assembly B: Grounding path for capacitor 42 is removed.

(5) Turning outer knob 18 to its other extreme position and holding there: Contacts K are closed and contacts K are opened.

(6) Depressing, and holding depressed, the button of assembly C: C contacts switched to states other than normal.

(7) Depressing, and holding depressed, the button of assembly D: D contacts switched to states other than normal to complete path from capacitor 45, through resistor 44, contacts D and C and relay 32 to capacitor 42. The charge on capacitor 45 is divided between capacitors 42 and 45. The current produced thereby releases relay 32. When the relay releases, the alarm is deactivated and extension arm 33 is returned to its normal position.

(8) Releasing the button of assembly C: C contacts returned to normal and remainder of charge on capacitor 45 is discharged through resistor 44 and contacts D and C (9) Releasing the button of assembly D: D contacts returned to normal thereby breaking the discharge path for capacitor 45.

(l0) Returning knob 18- to its original position: Limit switch 37 recloses its contacts, thereby completing the path between battery 41 and capacitor 42. Interposer member 29 is deflected by extension arm 33 and radial arm 21 is engaged and carried along with the interposer arm. Shaft 17 and latch tripping arm 28 are rotated and door is unlocked.

(11) Releasing knob 18: Knob 18 is rotated by spring 22 until spring 31 disengages interposer member 29. When interposer member is released, all of the elements return to original positions. When door is closed, it is again locked. Limit switch 35 is released, thereby removing a ground so that capacitor 42 is charged from battery 41.

The above steps illustrate how the lock is opened when the opening combination is followed. A few of the actions produced when the opening combination is not followed are now considered.

(1) Turning knob 18 before doing anything else (see top horizontal line of FIGS. 8A through 8B): Limit switch 35 is operated and capacitor 42 is discharged through relay 32 and contacts K37, C K and B to ground and relay is operated and remains operated. All of charge is dissipated and charging circuit is disabled. Alarm is activated. Relay cannot be released unless special reactivating combination is used. (This is discussed later);

(2) Operating the button of assembly B, C or D before doing anything else (see second from top horizontal line of FIGS. 8A through 8B): A conducting path from capacitor 42 through relay 32 to ground is provided and the charge on capacitor 42 is discharged through the relay. The relay is operated and remains operated. All of the charge is dissipated and charging circuit is disabled. Alarm is activated. Relay cannot be released unless special reactivating combination is used.

(3) Operating the button of assembly E, F, G, H or J before doing anything else (see second from top horizontal line of FIGS. 8A through 8B): A conducting path from capacitor 42, through relay 32 and a diode 46 to ground is provided and the same result as described above in 2 is produced.

(4) Operating the button of assembly A after the opening combination has been followed to the point where the button of assembly A is released: The path comprising contacts A and a diode 47 is enabled and the charge in capacitor 45 divides between capacitors 42 and 45. Charge in capacitor 45 is dissipated to level where it cannot subsequently produce current necessary to release relay 32. Alarm remains activated. Relay cannot be released until reactivating combination is used.

(5) Operating button of assembly E, F or I after the opening combination has been followed to the point where the button of assembly A has been released: The charge on capacitor 45 is discharged to ground by way of a diode 48. Alarm remains activated. Relay can be released only by reactivating combination.

Other actions that result in failure are believed readily apparent from the sequence chart.

From the above discussion, it is apparent that an incorrect operation of the pushbuttons or knob 18 causes relay 32 to operate and, furthermore, discharges capacitors 42 and 45 so that energy is not available to release the relay. The disclosed embodiment will not, therefore, respond to a subsequent application of the opening combination because of the absence of releasing energy. In accordance with a feature of the invention, the embodiment is reactivated so as to respond to the opening combination by using a second combination that releases the relay and restores the embodiment to its normal state. This feature is now discussed in detail.

To reactivate the lock, knob 18 must first be in its normal position. The buttons of assemblies G and H are then depressed and held for a short period. This permits battery 41 to place a charge on a capacitor 48 by way of a resistor 49. The button of assembly I is then depressed and the charge in capacitor 48 is divided between capacitors 48 and 42. The current flowing during this division causes relay 32 to release and the path between battery 41 and capacitor 42 is again conductive. The buttons of assemblies G, H and J are then released. After a short charging time for capacitor 42, the lock is reactivated;

that is, it is in its original state so that the latch can be withdrawn in response to the opening combination.

Although it is not shown in the drawings, a mechanical arm may be afiixed to shaft 17 so that relay 32 is physically released when inside knob 19 is turned. This will cause the lock to be reactivated when someone inside answers the door upon hearing the alarm.

Although only one embodiment of the invention has been disclosed and described in detail, various other embodiments may be produced without departing from the spirit and scope of the invention.

What is claimed is:

1. In combination first and second members normally movable with respect to one another,

an interposer member mounted on said first member and movable therewith in a first path between first and second positions,

first means in said first path blocking movement of said interposer member from said first to said second positions,

second means directing said interposer member moving from said second position toward said first position into a second path to engage said second member to move said second member with said first member, and

third means to move said first means out of said first path.

2. A combination in accordance with claim 1 in which said third means comprises a magnetic latching relay having a coil and a set of normally closed contacts, and

said combination further comprises first and second limit switches which are open only when said interposer member is in its first and second positions, respectively,

first and second capacitors each having first and second terminals,

a source of direct current potential which source has first and second terminals,

a point of reference potential connected to said second terminals of said capacitors and said second terminal of said source,

a first path connected from said source first terminal to said first capacitor first terminal which path comprises said relay contacts, said second limit switch and said relay coil in that order,

a second path connected between said second capacitor first terminal and the junction of said second limit switch with said relay coil, and

a third path connected between said second capacitor first terminal and the junction of said relay contacts with said second limit switch,

said second and third paths each including a respective pair of switches where each switch has a pair of normally open contacts and at least one switch in each pair is a single-pole double-throw switch,

each pair of said switches connected in its path so that said normally open contacts are connected in series in the path, the common contacts on the single-pole double-throw switches are connected to their adjacent switches, the remaining contacts on said singlepole double-throw switches are connected to said point of reference potential, a single-pole doublethrow switch in said second path is connected electrically nearer to said relay coil than the other switch in said second path and a single-pole double-throw switch in said third path is connected electrically nearer to said second capacitor than the other switch in said third path.

3. A combination in accordance with claim 2 in which all of said switches are single-pole double-throw switches,

fourth and fifth paths are connected between said second capacitor first terminal and the junction of said relay coil with said second limit switch,

said fourth path including a normally open switch which is closed at the same time of closing of said normally open contacts on said second path switch closer to said relay coil,

said fifth path including said first limit switch and a single-pole double-throw switch where said first limit switch is serially connected in said path between the common contact on said last mentioned switch and said relay contacts, the normally open contacts of said last mentioned switch are connected in series in said fifth path, the normally closed contacts of said last mentioned switch are connected to said reference potential and said last mentioned switch is operated at the same time as said third path switch closer to said second limit switch,

a diode connected between said first capacitor first terminal and the common contacts of said switches in said third path and poled for charge transfer from said second capacitor to said first capacitor, and

a normally open switch connected between said point of reference potential and said junction between said relay contacts and said second limit switch and operated at the same time as said second path switch closest to said second capacitor.

4. A combination in accordance with claim 3 which further comprises a sixth path connected in shunt with said relay contacts and comprising a plurality of switches which when operated in a predetermined sequence cause a releasing current to pass through said relay coil, and

a seventh path connected in shunt with said third, fourth and fifth paths to produce a completed circuit to said point of reference potential when said switches in said sixth path are not operated in said predetermined sequence.

5. A combination lock circuit comprising a magnetically latching relay having a coil and a pair of normally closed contacts,

first and second capacitors,

a source of direct current potential connected in series with said relay contacts and said first capacitor to place energy in said first capacitor when said relay is in its released state,

a first path comprising a pair of switches to discharge said first capacitor with a portion of said energy being transferred to said second capacitor by way of said relay coil and the remainder of said energy being dissipated when said switches are operated and released in a predetermined sequence and, furthermore, to dissipate all of said energy by way of said relay coil when said switches are operated and released other than in said predetermined sequence,

a second path comprising a second pair of switches to discharge said second capacitor with a portion of the energy therein being transferred to said first capacitor by way of said relay coil and the remainder of the energy being dissipated when said second pair of switches are operated and released in a predetermined sequence after said first pair of switches are operated and released in their predetermined sequence, to dissipate energy in said first capacitor by way of said relay coil and to dissipate energy in said second capacitor when said second pair of switches are operated in the wrong sequence and, furthermore, to dissipate energy in said first capacitor by way of said relay coil when said switches are released in the wrong sequence.

6. A combination lock circuit comprising a magnetically latching relay having a coil and a set of normally closed contacts,

first and second capacitors each having first and second terminals,

a source of direct current potential which source has first and second terminals,

a point of reference potential connected to said second terminals of said capacitors and said second terminal of said source,

a first path connected from said source first terminal to said first capacitor first terminal which path comprises said relay contacts and said relay coil in that order,

a second path connected between said second capacitor first terminal and the extremity of said relay coil closer to said relay contacts, and

a third path connected between said second capacitor first terminal and the one of said relay contacts closer to said relay coil,

said second and third paths each including a respective pair of switches Where each switch has a pair of normally open contacts and at least one switch in each pair is a single-pole double-throw switch,

each pair of said switches connected in its path so that said normally open contacts are connected in series in the path, the common contacts on the single-pole double-throw switches are connected to their adjacent switches, the remaining contacts on said single- References Cited UNITED STATES PATENTS 3,266,276 8/ 1966 Yulkowski 70-110 3,170,093 2/ 1965 Gilbert 317-135 3,201,658 8/1965 Reynolds 317151 3,326,024- 6/1967 Dreyfus, et al 70-351 MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE, Assistant Examiner US. Cl. X.R.

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