US2831129A - Electric combination locks - Google Patents

Electric combination locks Download PDF

Info

Publication number
US2831129A
US2831129A US542819A US54281955A US2831129A US 2831129 A US2831129 A US 2831129A US 542819 A US542819 A US 542819A US 54281955 A US54281955 A US 54281955A US 2831129 A US2831129 A US 2831129A
Authority
US
United States
Prior art keywords
contact
arm
lock
series
contacts
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US542819A
Inventor
Earl R Penney
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Security E Lock & Safe Co Inc
Security E-Lock & Safe Co Inc
Original Assignee
Security E Lock & Safe Co Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Security E Lock & Safe Co Inc filed Critical Security E Lock & Safe Co Inc
Priority to US542819A priority Critical patent/US2831129A/en
Application granted granted Critical
Publication of US2831129A publication Critical patent/US2831129A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • GPHYSICS
    • G07CHECKING-DEVICES
    • G07CTIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
    • G07C9/00Individual registration on entry or exit
    • G07C9/00174Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys
    • G07C9/00658Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated by passive electrical keys
    • G07C9/00666Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated by passive electrical keys with dials
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T70/00Locks
    • Y10T70/70Operating mechanism
    • Y10T70/7051Using a powered device [e.g., motor]
    • Y10T70/7062Electrical type [e.g., solenoid]

Definitions

  • Figure l is a front elevational view showing the control knobs and dials
  • FIG. 2 is a section taken on line 22 Figure 1;
  • Figure 3 is a section taken on line 33 Figure 2;
  • FIG. 4 is a section taken on line 4-4 Figure 2;
  • Figure 5 is a section taken on line 5-5 Figure 4.
  • Figure 6 is a circuit diagram.
  • reference numeral 10 designates the door or wall of a room of which the door is locked by means of the present lock, which will now be described.
  • the invention will be described as if the several parts of the lock are carried by the door to be locked, although it is evident that, since the locking bolt is electrically operated it may be positioned at a distance from the control mechanism, as for example, the door of a garage may be locked and unlocked from the residence.
  • Attached to the outside of the door as by screws or bolts 12 is a metal plate 11.
  • the rear surface of the plate has a hub 13 that projects into the door or wall to any depth desired.
  • the front side of the plate is provided with three concentric circles of deep depressions or holes 14, spaced cquiangularly as shown in Figure l.
  • the outer circle has thirty-seven holes numbered as shown in Figure 1, one hole being designated by (l which is shown as located at the top in Figure l, the other thirty-six holes being numbered 1 to 9 in four groups which have been designated by letters A, B, C and D, dividing the scale into four quadrants.
  • the intermediate scale has twenty-seven holes or depressions, one being designated by O and the others, in a clockwise direction, by letters A to Z.
  • the inner scale has nineteen holes numbered consecutively in a clockwise direction from i to 19..
  • a tubular shaft 15 and journaled in the latter is a shaft 16 to the outer (left hand) end of which a circular disk ice 17 is attached; this disk may be referred to hereinafter as a knob because it corresponds to the member so designated in connection with a permutation lock.
  • a pointer 38 is attached to the outer end of shaft 15' as shown in Figure 2.
  • Disk 37 has an indicator or pointer 19. Attachcd to the inner surface of the door by spacer brackets 29, only one of which has been shown, is a plate 21 of insulating material that has a central opening through which shaft 16 extends.
  • a compression spring 25' surrounds the inner end of the shaft and is held under compression by washer 24 and pin 25.
  • Flate 21 has three concentric circles of holes that correspond in angular, and preferably also in radial position with the depressions or holes 14 in plate 11.
  • a frat headed stove bolt 26 preferably made from copper. These bolts are secured in place by nuts and washer as shown, and the ends of the flat heads are flush with the outer surface of plate 21 as shown in Figure 2.
  • shafts 15 and 16 together carry three contact arms which for convenience have been designated by letters E, F and G, being respectively the outer, intermediate and inner arms.
  • Arm E is attached to the inner end of shaft 15 and spaced therefrom by an insulating sleeve 27.
  • the end of arm E that encircles the shaft is split as shown in Figure 3 and is clamped to the shaft by bolt 2%
  • Arm F is constructed like arm E and is insulated from shaft 16 and clamped thereto in the same manner as arm E.
  • Arm G is insulated from shaft 16 by an insulating sleeve but instead of being clamped to shaft 16 is mounted for free rotation thereon.
  • the part which encircles the shaft and which will be referred to as hub 29 has a frustoconical surface and is positioned in a correspondingly shaped depression in friction cup 30 that is held from accidental rotation by lug 31.
  • Arms E and F are each provided with a cylindrical depression 32 in which is positioned a carbon brush 33 that is urged outwardly by a spring as shown.
  • Arms E, F and G have laterally projecting ends that terminate in a plane and are each provided with a carbon brush 33 which is urged outwardly by a spring.
  • Arm F has a lug 34 that laps over one side of arm G as shown in Figures 2 and 4. It will be noted from Figure 4- that when lug 34 is in contact with the side of arm G both carbon brushes 33 are on the same radius which is a structural feature of considerable importance.
  • the contact arms may be turned to any desired rotarial position.
  • Arm G can be turned in a clockwise direction to any desired position by turning disk 17 after which arm F is turned in a reverse direction to its position after which arm E is positioned by moving the pointer.
  • Figure 6 is a diagram but shows the position of all of the contacts 26 as if they were seen looking in the direction of arrow 6 in Figure 2 and the several contacts are arranged in the same relation as the depressions or holes 14 in Figure l, and are identified by the same letter and numerals.
  • pointer 18 is positioned in hole 1 the carbon brush 33 will be in electrical contact with contact 1 in the outer circle and the same is true with the other contact arms.
  • Figure 6 shows the electrical circuits comprising the lock.
  • the circles that have been identified by numbers and let ters correspond to the bolts 26 and the full lines 35 interconnecting the circles represent electrical conductors. It will be observed that some of the circles are not connected to conductors as but are blanks whose function is to confuse an unauthorized person trying to open the lock.
  • the full line radial lines represent the contact arms which are shown in unlocking position.
  • Number 35 represents the power line and 37 a normally open two-pole switch, while numeral 33 represents a solenoid retractable locking device and 39 a burglar alarm which may be positionerl in any suitable place.
  • pawl 40 holds a door in locked position and that the proper person desires to unlock it.
  • the combination or seting is arm E at contact 1 in quadrant D and arm G at contact 17.
  • Arm E is moved onto contact 1 by means of pointer 18 and the end of the pointer is inserted into depression or opening 1 in quadrant D of the outer circle.
  • the operator then turns disk 17 in a clockwise direction until pointer 19 indicates opening 17 in the smallest circle. After this he turns 17 counter-clockwise until pointer 19 points to C in the intermediate circle; he now closes switch 37 and energizes solenoid 38 thereby retractingthe pawl.
  • Arm F connects the plus terminal to contact C in the intermediat row and this contact is joined to one terminal of the alarm bell or signal by conductor 45, but since the other terminal of the alarm device is connected by wire 42 to the positive side of the circuit the alarm will not operate.
  • the setting 117 is the only one that will open the lock and'is the only setting that will open the lock without operating the alarm.
  • arms E, F and G are shown by broken lines in another of innumerable positions. Arm E is shown on contact 1 in quadrant D and is, therefore, electrically connected with the positive side of the circuit.
  • a first series of contacts some or" which are electrically connected to the negative side of a current source and at least one of which is connected to the positive side thereof, a first contact arm adapted to form an electrical connection with any contact ot the first series, a second series of contacts at least one of which is electrically connected to the positive side of an electrical device to be operated, the negative side of said device being electrically connected to the negative side of the current-source, a econd contact arm electrically connected betweenthe first contact arm and any selected contact of the second series, said electrical device being operated when the first contact arm is electrically connected to a positive contact of the first series and the second contact arm is connected to the positive contact of the secondseries, a third series of electrical contacts some of which are electrically connected to the negative side of a second electrical device to be operated, the positive side of said-second device being electrically connected to the positive side of the current source, and a third contact arm electrically connected between the first contact arm and any selected contact of the thirdseries, the second electrical device being operated when
  • a device in accordance with claim 1 in which only one contact of the first series is connected to the positive side of the current source.
  • a device in accordance with claim 1 in which only one contact of the first and second series is connected to the positive side of the current source.
  • a device in accordance with claim 8 in which part of the remaining contacts of each series are dead.

Description

April 15, 1958 E. R. PENNEY ELECTRIC COMBINATION LOCKS 2 Sheets-Sheet 1 Filed Oct. 26, 1955 INVENTOR. EARL R. PENNEY BY Z Q ATTORNEYS April 15, 1958 E. R. PENNEY 2,831,129
ELECTRIC COMBINATION LOCKS Filed Oct. 26. 1955 2 Sheets-Sheet 2 i 45 I i l I 4/- 59 L I f I 68 57 L F V 34 6&-
INVENTOR. EAAZL R PE/VNEY ATTORNEYS United States Patent ELECTRIC co nrNATroN LOCKS Earl R. Penney, Englewood, Colt, assignor, by direct and mesne assignments, to Security E-Loclt 2: Safe Eon, 111e,, Englewood, (Zola, a corporation of Colorado Application October 26, 1955, Serial No. 542,819 9 Claims. (Cl. 307-113) This invention relates to improvements in locks and has reference more particularly to an improvement in electrically operated locks of a combination type.
In many places in private residences, shops, factories and office buildings it is frequently desirable to lock rooms containing clothing, tools, files, etc., which are not of suflicient value or importance to warrant the expense of a standard permutation lock and which does not require a key for its operation. Where a considerable number of persons are entitled to lock and unlock a room, cabinet or vault there must be many keys and these must be guarded against loss. It is also desirable at times to lock and unlock a door from a distance, as for example, a garage door. I
It is the object of this invention to produce a lock that will operate an audible or visual alarm or signal whenever someone not familiar with the proper combination attempts to open the lock by testing out a number of random settings.
Having thus briefly set out the objects of the invention the invention will now be described in detail for which purpose reference will be had to the accompanying drawing in which the invention has been illustrated, and in which; c
Figure l is a front elevational view showing the control knobs and dials;
Figure 2 is a section taken on line 22 Figure 1;
Figure 3 is a section taken on line 33 Figure 2;
Figure 4 is a section taken on line 4-4 Figure 2;
Figure 5 is a section taken on line 5-5 Figure 4; and,
Figure 6 is a circuit diagram.
Referring now to the drawings, reference numeral 10 designates the door or wall of a room of which the door is locked by means of the present lock, which will now be described. The invention will be described as if the several parts of the lock are carried by the door to be locked, although it is evident that, since the locking bolt is electrically operated it may be positioned at a distance from the control mechanism, as for example, the door of a garage may be locked and unlocked from the residence. Attached to the outside of the door as by screws or bolts 12 is a metal plate 11. The rear surface of the plate has a hub 13 that projects into the door or wall to any depth desired. The front side of the plate is provided with three concentric circles of deep depressions or holes 14, spaced cquiangularly as shown in Figure l. The outer circle has thirty-seven holes numbered as shown in Figure 1, one hole being designated by (l which is shown as located at the top in Figure l, the other thirty-six holes being numbered 1 to 9 in four groups which have been designated by letters A, B, C and D, dividing the scale into four quadrants. The intermediate scale has twenty-seven holes or depressions, one being designated by O and the others, in a clockwise direction, by letters A to Z. The inner scale has nineteen holes numbered consecutively in a clockwise direction from i to 19.. lournaled in hub 13 is a tubular shaft 15 and journaled in the latter is a shaft 16 to the outer (left hand) end of which a circular disk ice 17 is attached; this disk may be referred to hereinafter as a knob because it corresponds to the member so designated in connection with a permutation lock. A pointer 38 is attached to the outer end of shaft 15' as shown in Figure 2. Disk 37 has an indicator or pointer 19. Attachcd to the inner surface of the door by spacer brackets 29, only one of which has been shown, is a plate 21 of insulating material that has a central opening through which shaft 16 extends. A compression spring 25' surrounds the inner end of the shaft and is held under compression by washer 24 and pin 25. Flate 21 has three concentric circles of holes that correspond in angular, and preferably also in radial position with the depressions or holes 14 in plate 11. In each of the holes in plate 21 is positioned a frat headed stove bolt 26, preferably made from copper. These bolts are secured in place by nuts and washer as shown, and the ends of the flat heads are flush with the outer surface of plate 21 as shown in Figure 2.
Referring now in particular to Figures 2 to 5 from which it will be seen that shafts 15 and 16 together carry three contact arms which for convenience have been designated by letters E, F and G, being respectively the outer, intermediate and inner arms. Arm E is attached to the inner end of shaft 15 and spaced therefrom by an insulating sleeve 27. The end of arm E that encircles the shaft is split as shown in Figure 3 and is clamped to the shaft by bolt 2% Arm F is constructed like arm E and is insulated from shaft 16 and clamped thereto in the same manner as arm E.
Arm G is insulated from shaft 16 by an insulating sleeve but instead of being clamped to shaft 16 is mounted for free rotation thereon. In order to provide sufficient friction to prevent arm G from accidentally moving after it has been positioned the part which encircles the shaft and which will be referred to as hub 29, has a frustoconical surface and is positioned in a correspondingly shaped depression in friction cup 30 that is held from accidental rotation by lug 31. Arms E and F are each provided with a cylindrical depression 32 in which is positioned a carbon brush 33 that is urged outwardly by a spring as shown. Arms E, F and G have laterally projecting ends that terminate in a plane and are each provided with a carbon brush 33 which is urged outwardly by a spring. Arm F has a lug 34 that laps over one side of arm G as shown in Figures 2 and 4. It will be noted from Figure 4- that when lug 34 is in contact with the side of arm G both carbon brushes 33 are on the same radius which is a structural feature of considerable importance.
From the above description it will be seen that by the means so far described the contact arms may be turned to any desired rotarial position. Arm G can be turned in a clockwise direction to any desired position by turning disk 17 after which arm F is turned in a reverse direction to its position after which arm E is positioned by moving the pointer. Figure 6 is a diagram but shows the position of all of the contacts 26 as if they were seen looking in the direction of arrow 6 in Figure 2 and the several contacts are arranged in the same relation as the depressions or holes 14 in Figure l, and are identified by the same letter and numerals. When pointer 18 is positioned in hole 1 the carbon brush 33 will be in electrical contact with contact 1 in the outer circle and the same is true with the other contact arms.
Reference will now be had in particular to Figure 6 which shows the electrical circuits comprising the lock. The circles that have been identified by numbers and let ters correspond to the bolts 26 and the full lines 35 interconnecting the circles represent electrical conductors. It will be observed that some of the circles are not connected to conductors as but are blanks whose function is to confuse an unauthorized person trying to open the lock. The full line radial lines represent the contact arms which are shown in unlocking position. Number 35 represents the power line and 37 a normally open two-pole switch, while numeral 33 represents a solenoid retractable locking device and 39 a burglar alarm which may be positionerl in any suitable place.
Operation Let us now assume that pawl 40 holds a door in locked position and that the proper person desires to unlock it. The combination or seting is arm E at contact 1 in quadrant D and arm G at contact 17. Arm E is moved onto contact 1 by means of pointer 18 and the end of the pointer is inserted into depression or opening 1 in quadrant D of the outer circle. The operator then turns disk 17 in a clockwise direction until pointer 19 indicates opening 17 in the smallest circle. After this he turns 17 counter-clockwise until pointer 19 points to C in the intermediate circle; he now closes switch 37 and energizes solenoid 38 thereby retractingthe pawl. We will now trace the circuit and for convenience in tracing the current flow it will be considered that at the instant the switch is closed, the wire to the left in circuit 36 has a positive polarity and the one to the right a negative polarity as marked on the drawing. When the switch is closed conductors 41 and 42, which are both connected with the left-hand blade of switch 37, will be of the same polarity while conductor 43 will connect one terminal of the solenoid with the negative side of thecircuit. Current will now flow through conductor 41, thence through arms E and G to contact 17 from thence through conductor 44 to the solenoid and thence through conductor 43 thus completing the circuit and withdrawing the locking pawl, whereupon the door can be opened. Arm F connects the plus terminal to contact C in the intermediat row and this contact is joined to one terminal of the alarm bell or signal by conductor 45, but since the other terminal of the alarm device is connected by wire 42 to the positive side of the circuit the alarm will not operate. With the circuit connection as shown the setting 117 is the only one that will open the lock and'is the only setting that will open the lock without operating the alarm. In Figure 6 arms E, F and G are shown by broken lines in another of innumerable positions. Arm E is shown on contact 1 in quadrant D and is, therefore, electrically connected with the positive side of the circuit. Since practically all of the contacts in the intermediate circle are electrically connected by wire 35 and to one tcr minal of the alarm bell whose other terminal is connected with the positive side of the circuit it is evident that so long as arm E is in contact with any live contact in the outer circle the alarm will operate with all setting of arms E and F, except when arm E is in engagement with contact 1. As' shown in Figure 6 the lock will not open because the other terminal of the solenoid is connected with the negative side of the circuit. Other contacts in the outer circle may be connected in parallel with con tact 1, as for example, contact in quadrant D and this will give other settings for operating the lock. By connecting one or more of the contacts of the innermost circle with conductor 35 of the intermediate circle, by means of conductor 46 the alarm will operate whenever arm G engages such a contact.
When employed for locking a room or cabinet all of the parts shown to the right of wall 10 may be positioned inside the cabinet or room and cannot be tampered with. The operating mechanism shown in Figure 2 may be positioned in one building and the solenoid positioned to open and lock a door in another building in which case conductors 42, 43, 44 and 45 may be run through an underground conduit.
What is claimed as new is:
1. In an electric switch, a first series of contacts some or" which are electrically connected to the negative side of a current source and at least one of which is connected to the positive side thereof, a first contact arm adapted to form an electrical connection with any contact ot the first series, a second series of contacts at least one of which is electrically connected to the positive side of an electrical device to be operated, the negative side of said device being electrically connected to the negative side of the current-source, a econd contact arm electrically connected betweenthe first contact arm and any selected contact of the second series, said electrical device being operated when the first contact arm is electrically connected to a positive contact of the first series and the second contact arm is connected to the positive contact of the secondseries, a third series of electrical contacts some of which are electrically connected to the negative side of a second electrical device to be operated, the positive side of said-second device being electrically connected to the positive side of the current source, and a third contact arm electrically connected between the first contact arm and any selected contact of the thirdseries, the second electrical device being operated when-the first contact arm is electrically connected to any negative contact of the first series and the third contact arm is electrically connected to any negative contact of the third series.
2. A device in accordance with claim 1 in which only one contact of the first series is connected to the positive side of the current source.
3. A device in accordance with claim 1 in whichonly one contact of the second series is connected to the positive side of the first electrical device.
4. A device in accordance with claim 1 in which most of the contacts of the third series are connected to the negative side of the second electrical device.
5. A device in accordance with claim 1 in which some of the contacts of at least one of the series are dead.
6. A device inaccordance with claim 1 in which some of the contacts of the first and third series are dead.
7. A device in accordance with claim 1 in which some of the contacts of each series are dead.
8. A device in accordance with claim 1 in which only one contact of the first and second series is connected to the positive side of the current source.
9. A device in accordance with claim 8 in which part of the remaining contacts of each series are dead.
References Cited in the file of this patent UNITED STATES PATENTS 996,615 Carrigan July 4, 1911 1,118,024 Lawrence Nov. 24, 1914 2,677,814 Miller May 4,1954
US542819A 1955-10-26 1955-10-26 Electric combination locks Expired - Lifetime US2831129A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US542819A US2831129A (en) 1955-10-26 1955-10-26 Electric combination locks

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US542819A US2831129A (en) 1955-10-26 1955-10-26 Electric combination locks

Publications (1)

Publication Number Publication Date
US2831129A true US2831129A (en) 1958-04-15

Family

ID=24165411

Family Applications (1)

Application Number Title Priority Date Filing Date
US542819A Expired - Lifetime US2831129A (en) 1955-10-26 1955-10-26 Electric combination locks

Country Status (1)

Country Link
US (1) US2831129A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2934615A (en) * 1956-03-21 1960-04-26 Goral Lewis Combination lock switch
US4107655A (en) * 1977-01-10 1978-08-15 Moorhouse John H Mechanical code for operated device for access to coded electrical circuits
US4322719A (en) * 1980-10-24 1982-03-30 Moorhouse John H Coded solid state entry device
US5219068A (en) * 1991-07-16 1993-06-15 Cincinnati Milacron, Inc. Adjustable proximity switch mounting assembly
US20140218168A1 (en) * 2013-02-07 2014-08-07 Schlage Lock Company Llc Multi-control entry door hardware

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US996615A (en) * 1909-08-09 1911-07-04 Auto Safety Specialty Company Electric switch.
US1118024A (en) * 1913-08-27 1914-11-24 Jacob J Geisen Electrical switch.
US2677814A (en) * 1950-09-05 1954-05-04 Harry C Miller Electrical permutation lock

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US996615A (en) * 1909-08-09 1911-07-04 Auto Safety Specialty Company Electric switch.
US1118024A (en) * 1913-08-27 1914-11-24 Jacob J Geisen Electrical switch.
US2677814A (en) * 1950-09-05 1954-05-04 Harry C Miller Electrical permutation lock

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2934615A (en) * 1956-03-21 1960-04-26 Goral Lewis Combination lock switch
US4107655A (en) * 1977-01-10 1978-08-15 Moorhouse John H Mechanical code for operated device for access to coded electrical circuits
US4322719A (en) * 1980-10-24 1982-03-30 Moorhouse John H Coded solid state entry device
US5219068A (en) * 1991-07-16 1993-06-15 Cincinnati Milacron, Inc. Adjustable proximity switch mounting assembly
US20140218168A1 (en) * 2013-02-07 2014-08-07 Schlage Lock Company Llc Multi-control entry door hardware
US9443364B2 (en) * 2013-02-07 2016-09-13 Schlage Lock Company Llc Multi-control entry door hardware

Similar Documents

Publication Publication Date Title
US3633167A (en) Security system
US2923928A (en) mclaughlin
US2831129A (en) Electric combination locks
US3392559A (en) Pulse duration coded electronic lock and key system
US4051548A (en) Electric locking device
US3852737A (en) Product vending machine alarm
ES407928A1 (en) Door locking means
US3609742A (en) Property security system
US3596014A (en) Burglarproof lock
US3980844A (en) Combination lock and switch device
US3543096A (en) Method and apparatus for sensing and correcting an overloaded electrical circuit
US3755718A (en) Combination electric lock
US3723682A (en) Combination controlled actuating device
US3259707A (en) Electrical door signal
US3453402A (en) Electrical three-part,keylocked switch
US1047105A (en) Alarm-lock.
US2136677A (en) Door lock safety device
US3600643A (en) Security system
US3745551A (en) Alarm apparatus and method
US1102571A (en) Alarm for protecting permutation-locks.
US4008465A (en) Keyless anti-theft entry system
USRE27013E (en) Key-actuated electronic security system
US3663867A (en) General purpose presettable electro-mechanical combination safety lock device
US542643A (en) Charles heyman
US438236A (en) And frederick s