Magnetic locking status detection system

• US 4,516,114 A
• Filed: 03/07/1983
• Issued: 05/07/1985
• Est. Priority Date: 03/07/1983
• Status: Expired due to Term

• Current Assignee: Securitron Magnalock Corporation (Assa Abloy AB)
• Original Assignee: Securitron Magnalock Corporation (Assa Abloy AB)
• Inventors: Cook, Robert C.
• Primary Examiner(s): Ruehl, Charles A.
• Assistant Examiner(s): Lau, Chi K.
• Application Number:
  US06/473,010
• Time in Patent Office: 792 Days
• Field of Search: 340/542, 340/547, 340/567, 340/551, 73/DIG. 3, 361/143, 324/260, 70/91, 292/251.5, 335/253, 335/254, 335/285, 335/286, 335/289
• US Class Current: 340/542
• CPC Class Codes: G08B 13/08 by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind

Abstract

Magnetic door locks characteristically include a high strength electromagnet and a mating plate made of magnetically permeable material, or door strike, mounted on the door frame and the door, respectively. In addition, in order to determine whether the door strike is in engagement with the electromagnet, detection arrangements are provided; and in the present case, simplified detection arrangements are provided by separate portions of the electromagnetic core separated by non-conducting shims or the like, and the closing of a detection circuit extending between the two portions of the electromagnetic core by the magnetic and electrically conducting door strike bridging between the two sections of the core. In addition, the detection circuit may be electrically connected in parallel with electromagnet energization circuit, to positively indicate both that the electromagnet is energized and that the door is closed.

Claims

1. A magnetic lock and status detection system for a door or the like comprising:

an electromagnet having a core structure made of conductive magnetic material and having at least two separate core portions insulated from one another;

a magnetic strike plate made of conductive magnetic material;

means for mounting said electromagnetic and strike plate on a door and a door frame, respectively, for relative movement between a closed position wherein said strike plate engages both of said two separate core portions, and an open position wherein the door is open and said strike plate is spaced from said electromagnet;

an electrical control and sensing unit, said electrical control and sensing unit including door closure detection circuit means;

means for supplying power to said electromagnet from said electrical control and sensing unit; and

electrical connections from said detection circuit means of said control and sensing unit to each of said two separate core portions;

whereby the engagement of said strike plate with said two separate core sections and the resultant closure of an electrical path between said electrical connections indicates to said detection circuit means whether the door is open or closed.

2. A magnetic lock and status detector system for a magnetic lock for a door or the like as defined in claim 1 wherein said electromagnet has an E-shaped core structure, with said core portions also being of E-shaped configuration, and being spaced from one another, and including a single electrical coil extending around the center leg all of said E-shaped core portions.

3. A magnetic lock and status detector system as defined in claim 1 including means for applying electrical power to said electromagnet and to one of said core portions in parallel, whreby a sensed output from the other core portion confirms both that the electromagnet is energized and also that the strike plate is in engagement therewith.

4. A magnetic lock and status detection system as defined in claim 1 wherein plastic means are provided for encapsulating said electromagnet with the pole pieces of said core portions.

5. A magnetic lock and status detection system for a door or the like comprising:

an electromagnet assembly including an exposed faceplate;

said electromagnet assembly including electrically insulated spaced electrically conductive members extending to said faceplate;

a magnetic strike plate made of conductive magnetic material;

means for mounting said electromagnet assembly and strike plate on two relatively movable members, for movement between a closed position wherein said strike plate engages said faceplace and an open position wherein the movable members are spaced apart from one-another and said strike plate is spaced from said electromagnet;

an electrical control and sensing unit, said electrical control and sensing unit including door closure detection circuit means;

means for supplying power to said electromagnet from said electrical control and sensing unit; and

electrical connections from said detection circuit means of said control and sensing unit to each of said two separate electrically conductive members;

whereby the engagement of said strike plate with said two separate electrically conductive members and the resultant closure of an electrical path between said electrical connections indicates to said detection circuit means whether the door is open or closed.

6. A magnetic lock and status detection system as defined in claim 5 wherein said two electrically conductive members are portions of a magnetic core forming part of said electromagnet.

7. A magnetic lock and status detection system as defined in claim 5 further including means for mounting said electromagnet and said strike plate on a door and a door frame.

8. A magnetic lock and status detection system for a magnetic lock for a door or the like as defined in claim 6 wherein said electromagnetic has an E-shaped core structure, with the core portions also being of E-shaped configuration, and being spaced from one another, and including a single electrical coil extending around the center leg all of said E-shaped core portions.

9. A magnetic lock and status detector system as defined in claim 5 including means for applying electrical power to said electromagnet and to one of said electrically conductive members in parallel, whereby a sensed output from the other conductive member confirms both that the electromagnet is energized and also that the strike plate is in engagement therewith.

10. A magnetic lock and status detector system as defined in claim 6 wherein said electromagnet assembly includes plastic means for encapsulating the electromagnet.