US2855588A - Combination lock and burglar alarm - Google Patents

Description

Oct. 7,1958 H. w. ALLEN 2,855,588

COMBINATION LOCK AND BURGLAR ALARM Filed Sept. 15, 1954 \F INVENTOR.

HARRY W. ALLEN BY United States Patent CQMBINATION LOCK AND BURGLAR ALARM Harry W. Allen, Dayton, Ohio Application September 15, 1954, Serial N0..456,115

' Claims. (Cl. 340-276) This invention relates to electrical locks and more particularly to an improved sequence operated lock system incorporating burglar alarm and other protective features.

The invention apparatus includes a novel coder unit in conjunction with a sequence operated relay system of an improved nature and a push button control means whereby on demand a new code may be set in the system in a substantially instantaneous fashion by a simple adjustment of the coder unit. Further, the improved relay system has interconnectedtherewith disabling means whereby in sequentially operating the push button control elements to solve the look, if there is any deviation from the exact preset code for opening the lock, whether ahead of or behind the proper sequence, the system is automatically and completely reset. Resultingly, the person attempting to solve the lock without the proper code, which may be changed on an instants notice, would have an impossible situation since each time that a misstep occurs the system automatically resets without the knowledge of the operator and this facilitates ready apprehension of an unauthorized intruder. A further feature of the invention is a selective tamper and delay arrangement so related to the disabling means and alarm signalling means as to provide an alarm regardless of the order in which the push buttons are pushed to close the circuits to the relays if either the wrong circuits are closed thereby or a delay over a predetermined set time period occurs between the actuation of any successive push buttons. In this event both an alarm signal results and an automatic reset of the whole system. In view of the great number of possible solutions of the lock presented to one who is not familiar with the correct combination, it is difficult for intruders to effect a solution and opening of the look without giving an unseen or unevidenhalarm. Further protection is afforded by the provision in the system for an automatic alarm being actuated upon cutting of the main power supply which is accompanied by an automatic switching in of stand-by power to continuously maintain the locked condition of the lock and this alarm cannot be turned oif except at a remote control point. In addition, if both main and stand-by power sources should fail, the lock remains continuously closed and cannot be opened except by the provision whereby a portable power source may be connected in the system at the push button control box and the lock operated, but only by the use of the proper code operation of the push buttons.

An object of this inventionis. to provide an improved combination lock and burglar alarm.

Another object of this invention is to provide an improved lock and burglar alarm which is sequence operated in accordance with a preset code and wherein an improved coder unit is providedwhereby the code may be changed on demand ahnost instantaneously.

A further object of the invention is to provide a novel electrical lock and burglar alarm which is sequence operated in accordance with a preset code and wherein disabling means are provided and so arranged as to cause an automatic and complete reset of the system on any deviation from the preset code, either ahead of or behind the proper sequence, without any indication thereof to the intruder.

An additional object of the invention is to provide a novel electrical lock and burglar alarm which has a sequence operated relay control system arranged in a suitable fashion in conjunction with a selective tamper and delay means so as to provide an automatic reset of the system without notice thereof to an intruder attempting to solve the lock, the automatic reset being accompanied by a remote alarm signal to facilitate apprehension of the intruder in the act of attempting toopenthe lock.

Another object of the invention is to provide a new and improved combined electrical lock and burglar alarm which incorporates stand-by power to always maintain a locked condition in the event that the main power supply either fail or be cut with an additional provision for a continuing alarm to result at a remote point to serve notice of the power failure and to facilitate apprehension of an intruder if such should be the cause of the power failure.

An additional object of the invention is to provide a novel electrical lock and burglar alarm whereby if all power sourcesfail, provision is made at the push button control unit for the application of an emergency power source to the system so that the lock can beopened on application of the proper code to the control unit.

These are but a few of the broad objects of the invention and many other objects and advantages of the invention will become readily apparent from the following description thereof when taken in conjunction with the accompanying drawings wherein:

Fig. 1 shows a schematic of the electrical lock and burglar alarm constituting the subject invention.

Fig. 2 showsa partial view of the code box in schematic fashion as employed in the practical embodiment of the invention illustratively presented.

The combination lock and burglar alarm apparatus constituting the subject invention can best be seen with reference to the illustrative practical embodiment thereof shown in the drawings. As shown, a power supply from a conventional v. A. C. source is directed, by the closing of switch S, to the primary of the transformer T through a fuse of a suitable current capacity. The transformer T has two windings taken off its secondary. The 30 v. Winding is connected to a fullwave bridge type rectifier R, while the second winding supplies 6 v. to two pilot lamps L1 and L2 for purposes to be described. The rectifier R provides 28 v. D. C. to the sequence operated relay system to be described and to a novel tamper alarm system interconnected therewith.

A relay K-8 connected into the main line following the rectifier R and also connected to ground is always energized when A. C. power is on, as shown, to close contacts 32 andopen contacts 30 and 31. Thus, the 28 v. D. C. is normally carried in the main line through the contacts 32, which constitute the back contacts of relay K and the forward contacts of relay K-8, and through normally closed contacts 5 of the disabling or reset relay K to provide main line supply voltage to the positive side of each of the interconnected sequence operated relays K-l through K-6.

In the use of the sequence control system of the invention any number of push buttons or control elements can be employed to operate the lock system and they must be operated in a predetermined sequence according to a preset code in order to effect an opening of the lock element. In the example shown eight buttons are employed in the control box ,as shown in Figure 2 of the drawings, and for purposes of illustration the coder unit has been set so that the push buttons must be operated to close control switches S-l through 8-6 in the following order; S-l, S2, S3, 84, and then S and S6 simultaneously to effect a solution of the code to open the lock. It is to be noted that regardless of the operating code that the relays are always energized in order K1 through K6 and any deviation from the preset code, which may be changed substantially instantaneously according to the invention, will cause an automatic reset of all the system and a simultaneous remote alarm as will be described.

The following is a detailed description of the operation of the novel combined lock and burglar alarm. First, push button 1 is operated closing switch S-l thereby. This completes a circuit from ground g through a two pole rotary switch R-l, in one pole, contact 1 thereof, through switch 8-1, out contact 1 of the other pole of R-l, through normally closed contacts 7 to the negative side of the coil of relay K-l to power to energize relay K-l closing contacts 6 and 8 thereof. The closing of contacts 8 provides a holding circuit for relay K-l from power through normally closed contacts 5 of disabling relay K, the coil of relay K-l, closed contacts 8 to ground to retain relay K-l energized when push button 1 is released and switch S-1 opens as a result.

Secondly, push button 2 is pushed closing switch S-2 and completing a circuit from ground g through closed contacts 6, in contact 2 on one pole of rotary switch R-2, through switch 5-2, out contact 2 of the other pole 'of rotary switch R-2, through normally closed contacts 9 to the negative side of the coil of relay K-2 and thus to power to energize relay K-2. The energization of relay K-Z closes contacts 10, 11 and 12 thereof. A holding circuit is provided from power through closed contacts 5, the coil of relay K-2, and closed contacts to ground to keep relay K-2 energized even when push button 2 is released opening switch S2.

Button number 3 is then operated closing switch 8-3. This provides a circuit from ground g through closed contacts 12 of relay K-2, in contact 3 of rotary switch R3, through switch S-3, and out contact 3 of switch R 3, through closed contacts 11 of relay K-2, normally closed contacts 13 of relay K4-, to the negative side of the coil of relay K3 and through to power to energize relay K3, closing contacts 14, 15 and 16 thereof. A holding circuit is provided for relay K-3 and a manner similar to the preceding relays through contacts 5, the coil of relay K-3, and contacts 14 to ground to maintain relay K-3 energized on release of push button 3.

Push button 4 is then pushed to close switch 8-4. This completes a circuit from ground g through contacts 16, in contact 4 of rotary switch R4, through switch S4, the out contact 4 of switch R-4, and through closed contacts 15 of relay K-3, normally closed contacts 17 of relay K5, to the negative side of the coil of relay K-4 and to power to energize relay K-4, closing contacts 18, 19 and 20 thereof. The closing of contacts 18 completes a holding circuit from power through the coil of relay K-4 to ground g to keep relay K-4 energized when push button 4 is released.

Then push buttons 5 and 6 are operated simultaneously to close switches 5 and 6 simultaneously. This closes a circuit from ground g through contacts 20, in contact 5 of rotary switch R-S, through the switches S-5 and 8-6, out contact 5 of rotary switch R-5, closed contacts 19 of relay K-4, through normally closed contacts 21 of relay K4 to the negative side of the coil of relay K-S to energize relay K-5, closing contacts 22 and 23 thereof. The closing of contacts 22 completes a holding circuit for relay K-S to ground g in a manner which is believed to be obvious. The closing of contacts 23 completes a circuit from ground g to the coil of relay K-6, closing Contacts 24 due to the resulting energization of the relay 4 and completing a circuit through contacts 24 to the magnetic rimlock to energize the lock to open it.

As has been noted previously if this precise operation is followed in the practical embodiment of the invention shown in accordance with the particular preset code, there is no difiiculty in opening the lock, but if there is the slightest deviation of any sort from the required procedure the lock will not open. Many safety factors have been included in a manner which renders the operation of the system available only to one who has possession of the specific code and then only if the code is applied with promptness and carefulness.

A provision has been made for emergency power supply to the system in the event of failure of the main power supply and this has been done in two supplemental ways. First, reference has been previously made to stand-by relay K-8 which remains energized as long as there is an effective A. C. power source under which condition contacts 30 and 31 are held open thereby. On failure of the main power supply, the relay K-8 becomes deenergized permitting contacts 30 and 31 to close. This automatically connects the system to a 24 v. stand-by battery through the closing of contacts 31. At the same time a circuit is completed through closed contacts 30 to power off alarm 4 and to ground to cause the alarm 4 to be energized and to signal an alarm until shut off after investigation of the reason of the power failure. Of course the pilot lamps also will go out to indicate power failure. Thus, an A. C. power failure does not interrupt the operative and locked condition of the system for even an instant. Also, a positive alarm which may provide a signal of any sort desired is immediately and continuously effected at a remote control point and for as long as the main power supply is out to notify of this difliculty. This is also a most important feature of the invention in that if a burglar or other unauthorized person cuts the main power line in an attempt to overcome the lock, an immediate alarm is sounded or signalled and without his knowledge and even when the main power is cut the lock remains completely effective.

A third source of power is available in the event of failure of stand-by power also, for any reason. As shown in sketch fashion in Figure 2 of the drawings, the eight push button control elements are located in a control box outside of the locked enclosure though all other components of the system are arranged elsewhere. A socket P is provided in conjunction with the push button control box. This socket P is connected to ground g and to the main line of the system as shown so that on plugging in of an emergency battery in the socket P, the lock may then be operated as usual but only on operation of the push buttons in exact manner according to the proper code.

If any person who does not know the exact sequence code should tamper with the push button control elements, the pressing of any one button in other than the proper sequence will energize relay K to automatically open and reset the system. For example, in the sequence arrangement shown, if the push button 3 were pushed after button 1 rather than button 2 as required by the preset code, the following would result. A circuit would be completed from ground g through contacts 11' since relay K-2 is still unenergized, through out contact 3 of rotary switch R-3, through switch S3, through in contact 3 of rotary switch R-3, and contacts 12, since relay K-2 is unenergized, to the negative side of the coil of the relay K which is the disabling relay to power. This energizes relay K causing the opening of contacts 5 thereof to thus open the system and cause a reset thereof to its non-operated condition. To solve and open the lock as is obvious, the sequence must be started all over. Similarly, if, in attempting to operate the lock, after the buttons 1, 2, and 3 are operated in proper sequence the button 2 is pushed again, a circuit is completed, since relay K-3 is already energized, from the ground g through contacts 6, in contact 2 of rotary switch R-2, switch S-2 closed by the pushing of push button 2 again, out contact 2 of rotary switch R-2, through contacts 9' closed on the energization of relay K-3 to the negative side of the coil of relay K and through to power. This energizes relay K to open contacts 5 thereof and thus automatically reset the system to its non-operated condition.

Thus, as can be readily seen, pushing a button out of the exact code sequence either ahead of or behind the proper order will disable the system and automatically reset it, the lock remaining unsolved and unopened. The intruder attempting an entrance and who at any point pushes a button out of sequence will not only fail to open the lock but will attract attention due to the delay created by theimproved disabling system presented by the invention which provides protection beyond that contemplated and eifected by the prior art devices. Each time that an error .is made the intruder has no knowledge thereof at any time so that the code cannot be solved by elimination.

There is a further complication in the possibility of a solution by an unauthorized person in a selective delaytamper circuit provided. Referring to the Figure l of the drawings, a double pole, double throw switch 5-9 is shown in the system and-having-a lock or delay position selectively available. When the switch 5-9 is in a lock position, then switches S7 and S-8 are included in the disabling circuit of the system. Thus, pushing either button '7 or 8 respectively associated with these switches will automatically put a ground g; on the disabling relay K to energize relay K to open main line contacts of relay Kvto automatically reset the system. This further and substantially increases the difficulty of an unauthorized person inadvertently opening the lock and insures a delay in the attempted operation by such a person as to make him more susceptible to apprehension. Also 'as'switch S-7 or 8-8 is closed, the remote alarm A2 is energized to warnof tampering by an unauthorized person.

When the switch 5-9 is set on delay, it will put a circuit in the system to reset the system when the person who is operating the code control buttons delays over a predetermined period between the pushing of successive buttons whether'he is following the proper code sequence or not. Closing any switch such as S1, for example, puts a ground on the negative side of the coil of delay relay K-7 through the delay setting of switch S-9. Since the positive side of relay K-7 is always connected to the main line, relay K-7 is energized thereby closing contacts 25 and 26 thereof. With a locked condition a circuit is then completed from ground g through microswitch 27, stop alarm switch 28, contacts 26, and through the coil of relay K-7 to power to provide a holding circuit to keep relay K-7 energized even after the push button 1 is released. 'As' contacts 25 are closed, a circuit is completed from ground g through the contacts 25 and the'delay tube 29 to power. If the succeeding button in the proper sequence is not actuated within a predetermined number of seconds, depending on the delay tube utilized, then the delay tube heater element in that delay interval heats up sufiiciently to close the contacts therein to apply the groundg to the negative side of the coil of the disabling relay K to energize relay K and open contacts 5 thereof to automatically reset the system as has been described. At the same time the tamper alarm -A2 which may be a buzzer or a signal light is set oif by the-closing of the contacts in the delay tube 29 thus to signal an attempted entry, providing an excellent alarm feature. As a matter of fact the system easily lends itself to use as a burglar alarm and fire alarm as well as by a mere insertion of a length 'of low temperature alarm and signal'wire in the circuit. The alarm that results from this delay-tamper circuit as provided by the invention will continueuritil the stop alarm switch, which may be in a suitable location, is pushed to open the circuit to the tamper alarm. This opens the circuit to the relay K-7 and causes it to be deenergized.

To provide means for releasing the lock from the inside of the locked enclosure when desired, the switch S-12 may be closed to energize the relay K-6 and open the lock in a manner obvious from Figure 1 of the drawings.

Another and most important feature of novelty provided by the invention lies in the coder section of the apparatus provided by'the invention. An exceedingly simple arrangement is provided by the coder section whereby the specific sequence necessary to operate the lock may be changed in instantaneous fashion on demand so as to further complicate an attempt made to learn the operating code by one who is unauthorized. The coder portion of the system as shown in Figure 1 of the drawings consists of five two pole, five position, rotary switches R1 through R-S, the poles thereof being connected into the relay system so as to provide for sequential operation thereof in direct sequence, in the example shown, as has been described previously. And, as a matter of fact there is always a direct successive operation of relays K-l through K-6 in the opening of'the lock and regardless of the set code. The position contacts of the respective rotary switches are respectively connected to switches S-1 through S-6 and the corresponding push buttons. By merely changing the contact settings of any two or more rotary switches so that a different setting is provided on each switch a new operating code is inserted in the system. For example, if it isdesired that the set code of the example shown in Figure 1 of the drawings shall be changed so that the push button sequence is 8-2, 8-1, 8-3, S4, and then S-5 and 8-6 simultaneously, this code is inserted by a quick turn of rotary switch R-1 to make position contacts"'2-2 and another quick turn of rotary switch R 2 to make position contacts 11. Then to open the lock the push button 2 must be pushed first. This completes a circuit from ground g through in contact 2 of rotary switch R-l, switch 8-2, out contact 2 of rotary switch R-l, through closed contacts 7 and to the negative side of relay K-l to power to energize K1 closing contacts 6 and 8 thereof. Then when button 1 is pushed next, a circuit is completed from ground g through closed contacts 6 in contact 1 of rotary switch R-Z, through switch S-1 and out contact 1 of rotary switch R-2, through contacts 9 and the negative side of the coil of relay K-2 to energize relay K-2. Of course the remainder of the sequential operation to open the lock has been previously set forth in the first example of code operation described and need not be repeated. It is obvious just how instantaneous the code change is effected, by a mere interchange of positioning of the respective rotary switches by turn of the dial members provided by the rotary switches. It is noted that variations in the interconnected code elements are readily apparent from this illustrative arrangement'of the rotary switches and such is contemplated within the scope of the invention depending on the application thereof.

The action of this novel combination lock and burglar alarm is positive in nature and foolproof. As has been set forth herein power failure will not permit opening of the lock thereby. Due to the improved relay interconnection, the slightest deviation from the exact code for operation of the lock whether ahead of or behind the proper sequence results in an automatic reset of the whole systemwhich is a provision that goes a novel step beyond the comparable prior art devices. By the combination of the improved delay-tamper circuit therewith, the probability of entrance of an unauthorized person Within the time limits set up is nil. Cutting or shorting of the system only actuates an alarm signal at a remote point and does not permit entry. The system is not frequency conscious nor can it be operated by induction or magnetic devices. And when a dead bolt type of lock is used therewith, the system cannot be overcome even by the use of tools or such methods of breaking and entering as drilling, blasting or torching. Such efforts to enter will only result in the actuation of an alarm signal and the apprehension of any intruder. The novel manner of automatic reset of the system without any indication whatsoever to the intruder brings yet a more distinctive advance in the art as provided by the invention.

While a single practical embodiment of the invention and a single application thereof has been set forth herein,

- many modifications and applications thereof are readily apparent therefrom and such is considered to be within the scope of the invention.

I claim:

1. Security apparatus comprising, a power supply means, a magnetically releasable lock means, a series of interconnected control means operatively connected thereto and sequentially operable to release said lock means, push button operating means operable in accordance with a variable pre-set code to energize said control means in sequential fashion to release said lock means,

code setting means selectively interconnecting said respective push button means with respective control means to energize said control means in said sequential fashion upon application of the set code to said push button means, said code setting means being instantaneously adjustable to change the operating code for energization of said control means in sequential fashion, disabling means so interconnected with said power supply means, said control means and said push button means as to automatically reset the apparatus if there is the slightest i deviation from the pre-set code either ahead of or behind the proper sequence operation of the push button means in attempting to release said lock means, and delay alarm means connected to said power supply means, said control means, said push button means and said disabling means and operative to simultaneously reset the apparatus and signal an alarm in the event the push button means are not successively operated within a pre-set period of time.

2. Security apparatus comprising, a power supply interconnected with said power supply means, said interconnected relays and said push button control means effective on the slightest deviation either ahead of or behind the set code to de-energize all relays to automatically reset the apparatus without notice to the operator, and tamper alarm means associated with said push button means and said de-energizing means effective to both give an alarm signal and cause automatic reset of the apparatus on any failure to apply the proper code to the push buttons with exactness and dispatch;

3. Security apparatus comprising, a main power supply means, a magnetically releasable lock means, a series of interconnected control means operatively connected thereto, and operable in accordance with a pre-set code, a series of push buttons operable in accordance with said pre-set code to sequentially energize said respective connected control means, and switch means selectively c011- nected between the push buttons and said control means and substantially instantaneously adjustable to set a desired sequence code for the operation of the push buttons to energize said control means in sequential fashion to release said lock means, disabling means interconnected with said main power supply means, means operatively connected with said disabling means and said interconnected control means and said push buttons and responsive to operation of said push buttons out of the set code sequence to energize said disabling means to automatically reset said control means necessitating initiation of the proper code sequence again for solution of the lock means and further means operatively connected between said disabling means and said interconnected control means and said push buttons responsive to operation of one of said push buttons a second time in the same sequence prior to completion of the proper sequence 'to energize said disabling means and automatically reset said control means.

4. Security apparatus comprising, a power supply means, a series of interconnected relays sequentially operable and connected to said power supply means, a lock means, a series of push button control elements for operating said relay means in sequential fashion, a series of code switches selectively and adjustably connected relative to said respective relays so that a predetermined code for sequential operation of said relays may obtain in substantially instantaneous fashion by adjustment of at least two switches, said push button control elements being connected to said relays through said switches to energize each of said relays in sequence by a selective operation of said push buttons either singly or plurally in sequence in accordance with the pre-set code to open said lock means, and disabling means interconnecting said power supply means, said push button elements and relays and being operable on any deviation ahead of or behind the proper sequential operation of the push button elements in accordance with the pre-set code to automatically reset the whole apparatus.

5. The structure as set forth in claim 4 and a selective tamper-delay means interconnecting said push button control elements and said disabling means and having an alarm means so associated therewith whereby successively on improper operation of said push button control elements or delay in the sequential operation of the successive relays the whole system will be automatically reset and an alarm efiected without any indication thereof to the operator.

6. Security apparatus comprising, a power supply means, a series of interconnected sequentially operable control means, a lock means, a series of code switch means selectively and adjustably connected to said respective control means so that a predetermined code for sequential operation of said control means may be provided in substantially instantaneous fashion by a readjustment of said switch means, a series of operating switch means connected to said control means through said code switch means to energize said control means in sequence by a selective closing of said operating switches either singly or plurally in sequence in accordance with a pre-set code, and a disabling relay interconnected with said power supply means, said operating switches and said control means and being operable on the slightest deviation from the pre-set code either ahead of or behind the proper sequence in closing said operating switches to automatically reset the apparatus Without any notice thereof being available to the operator said control means, switch means and code operating means having means so connecting them as to prevent solution of the lock by simultaneous operation of the code operating means and cause automatic reset of the apparatus upon such occasion.

7. Security apparatus comprising, a power supply means, a series of interconnected sequentially operable control means, a lock means, a series of operating switch means, a series of code setting means selectively and adjustably connected to said control means so that a predetermined code for sequential operation of said control means may be provided and set in substantially instantaneous fashion by an adjustment of at least two of said code setting means, said operating switch means being connected to said control means through said code setting means to energize said control means in sequence by a selective closing of said operating switches either singly or plurally in sequence in accordance with the preset code at any particular instant, and disabling means interconnected with said power supply means, said operating switches and said control means and being operable on the slightest deviation of any sort from the pre-set code for closing said operating switches to automatically reset the system Without any notice thereof to the operator, and means associated with said operating switch means effective on the application of an emergency power supply thereto in the event of the failure of the said power supply means operative to provide for the opening of said lock means upon operation of said operating switches but only when operated in exact accordance with the pre-set code.

8. Security apparatus comprising, a main power supply, a rectifier connected thereto, a series of relays operatively interconnected, a switching relay interposed and connecting between said series of relays and said rectifier and having a stand-by battery and an alarm associated therewith which are instantaneously operable on failure of the main power supply, a series of rotary switches interconnected with said relays and selectively adjustable to establish predetermined sequential operation of said relays, push button control means connected with said switches and operable to succesisvely energize said series of relays in accordance with the code set by said switches, a lock means connected with said relays for actuation thereby on application of the proper code thereto and a disabling relay so connected with said switching relay and each of said series of relays to automatically reset the system on operation of said push buttons either behind or ahead of the proper sequence or upon simultaneous operation of said push button control means.

9. Security apparatus comprising, power supply means, releasable lock means, a series of inter-connected control means operatively connected thereto and energizable in sequential fashion in accordance with an adjustable preset code, rotary switch means selectively connected to said control means and substantially instantaneously adjustable to set a desired code for closing circuits through said switch means to sequentially energize said interconnected control means for effecting a release of said lock means, code operating means selectively connected through said switch means to said control means in accordance with a pre-set code so that in each instance an application of the pre-set code in a precise undeviating fashion is required to release the lock means, a disabling relay, means connected to said disabling relay and interconnected with said inter-connected control means and said rotary switch means and responsive to operation of said selectively connected means out of their proper operating sequence to energize said disabling relay and automatically reset the control means, necessitating initiation of the proper code sequence again for solution of the security apparatus and further means connected with said disabling relay and inter-connected with said interconnected control means and a rotary switch means and responsive to operation of any of said selectively connected means a second time in the same sequence prior to completion of the proper code sequence to energize said disabling relay and automatically reset the control means.

10. Security apparatus comprising, a power supply means, a magnetically releasable lock means, a series of inter-connected control means operatively connected thereto and energizable in sequential fashion in accordance with an adjustable pre-set code, pivotally adjustable code setting means selectively connected to said control means and substantially instantaneously adjustable to set a desired code for closing circuits through said code setting means to sequentially energize said inter-connected control means to effect a release of said lock means, operating means selectively connectable through said code setting means to said control means in accordance with the pre-set code so that in each instance an application of said code must be effected in a precise and undeviating fashion to release said lock means, a disabling relay, means operatively connected with said disabling relay and inter-connected with said inter-connected control means and said code setting means responsive to operation of said selectively connected operating means out of their code operating sequence to energize said disabling relay and automatically reset the control means, and further means connected with said disabling relay and interconnected with said inter-connected control means and said code setting means responsive to operation of any of said selectively connected operating means a second time in the same sequence prior to completion of the proper code sequence to energize said disabling relay and automatically reset said control means, said control means, code setting means and operating means being so connected as to prevent solution of the lock by simultaneous operation of said operating means and cause automatic reset of said control means on such occasion.

References Cited in the file of this patent UNITED STATES PATENTS 893,802 Cleary July 21, 1908 1,324,499 Erickson Dec. 9, 1919 1,710,542 Landis Apr. 23, 1929 1,732,276 Morrison Oct. 22, 1929 1,905,965 Leschke Apr. 25, 1933 1,923,968 Chase Aug. 22, 1933 2,203,907 Hines June 11, 1940 2,225,715 Schneider Dec. 24, 1940 2,436,809 Joel Mar. 2, 1948 2,736,012 Bland et al Feb. 21, 1956

Images