ALARMS FOR NIGHT LATCH

• US 3,714,644 A
• Filed: 11/25/1970
• Issued: 01/30/1973
• Est. Priority Date: 11/25/1970
• Status: Expired due to Term

• Current Assignee: Harold Richard Hellstrom
• Original Assignee: Harold Richard Hellstrom
• Inventors: Hellstrom, Harold Richard
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Partridge, Scott F.
• Application Number:
  US05/092,673
• Time in Patent Office: 797 Days
• Field of Search: 340/274,276,280,380,256,273 200/61.62,61.81,61.93,61.08 174/34,36
• US Class Current: 340/508
• CPC Class Codes: E05B 45/005 Chain-locks, cable-locks or padlocks with alarms
• CPC Class Codes: E05C 17/365 Security chains
• CPC Class Codes: Y10T 292/283 Chain

Abstract

An alarm system includes a latch mechanism having a flexible connective member with one end anchored for example to a wall or door frame and the other end detachably securable to the door. Sensory means are extended along at least a portion of the flexible member, and circuit means are coupled to the sensory means for energizing an alarm mechanism upon occurrence of a malfunction in the sensory means.

Claims

1. An alarm system including a latch mechanism, said latch mechanism having a flexible connective member with one end capable of being anchored adjacent one of a door frame and an entrance door and the other end detachably securable to the other of said frame and said door to latch said door to said frame, said flexible connective member having a length sufficient to permit opening of said door to a predetermined and limited extent, an alarm mechanism, continuous conductive means extended along at least a portion of said flexible member, and circuit means coupled to said continuous conductive means and to said alarm mechanism for energizing said alarm mechanism upon stretching or breaking of the flexible connective member and occurrence of a malfunction in said continuous conductive means.

2. The combination according to claim 1 wherein said sensory means define a circuit path for arming said circuit means, and said circuit means include fail-safe means for energizing said alarm mechanism upon occurence of a break in said path.

3. The combination according to claim 1 wherein said sensory means include an electrically conductive circuit path and electrical shield means extended along said flexible member and juxtaposed to that portion of said path extending along said flexible member, said shield means and said path when shorted together by an attempt to break said flexible member providing said malfunction.

4. The combination according to claim 1 wherein switch means are provided for arming and disarming said circuit means, a keeper and keeper plate are provided as part of said latch arrangement, said switch means including at least one conductive strip located adjacent a slot in said keeper plate, said keeper being electrically conductive so as to arm said circuit means by a circuit path through said keeper and said strip upon engagement of said keeper and said keeper plate and so as to disarm said circuit means upon disengagement of said keeper and said keeper plate.

5. The combination according to claim 4 wherein said switch means include at least one elongated conductive strip substantially coextending with a keeper slot in said keeper plate.

6. The combination according to claim 1 wherein said sensory means include a continuity conductor passed back and forth at least once each way along said flexible member.

7. The combination according to claim 1 wherein said flexible member is a length of chain, and a length of said sensory means is interwoven with and passed along the length of said chain.

8. The combination according to claim 1 wherein said sensory means is secured at spaced positions along its length to The end portions of said flexible member respectively to aid in creating said malfunction in said sensory means when said flexible member is stretched or broken.

9. The combination according to claim 8 wherein an expansible member is incorporated in said flexible member to ensure malfunctioning of said sensory means upon striking of said flexible member but before severance thereof.

10. An alarm system including a latch mechanism, said latch mechanism having a flexible connective member with one end capable of being anchored adjacent one of a door frame and an entrance door and the other end detachably securable to the other of said frame and said door, an alarm mechanism, sensory means extended along at least a portion of said flexible member, and circuit means coupled to said sensory means for energizing said alarm mechanism upon occurrence of a malfunction in said sensory means, said circuit means being armed through a photoelectric relay, and said sensory means including a light source and a fiber optic elongated bundle extending from said light source to said photoelectric relay and along said flexible member.

11. An alarm system including a latch mechanism, said latch mechanism having a flexible connective member with one end capable of being anchored adjacent one of a door frame and an entrance door and the other end detachably securable to the other of said frame and said door, said flexible connective member having a length sufficient to permit opening of said door to a predetermined extent, an alarm mechanism, sensory means extended along at least a portion of said flexible member, circuit means coupled to said sensory means and to said alarm mechanism for energizing said alarm mechanism upon occurrence of a malfunction in said sensory means, said flexible member terminating in a conductive keeper, and a conductive keeper plate for detachably securing said flexible member to said other of said door and said frame, said sensory means including electrical conductors electrically connected to said keeper and to said keeper plate respectively so that said keeper and keeper plate are connected in a circuit including said sensory means and so that unauthorized disengagements of said keeper and keeper plate also results in said malfunction.

12. The combination according to claim 11 wherein switch means are provided for said circuit means for disarming said circuit means upon intentional disengagement of said keeper and said keeper plate.

13. An alarm system including a latch mechanism, said latch mechanism having a flexible connective member with one end capable of being anchored adjacent one of a door frame and an entrance door and the other end detachably securably to the other of said frame and said door, an alarm mechanism, sensory means extended along at least a portion of said flexible member, circuit means coupled to said sensory means for energizing said alarm mechanism upon occurrence of a malfunction in said sensory means, an anchor member for said flexible member fabricated from a conductive material, an electrical contact inserted between said anchor member and a non-conductive support therefor, and said sensory means including an electrical continuity loop having said anchor member and said electrical contact electrically connected therein so that said sensory means malfunctions upon breakage of said flexible member or upon loosening of said anchor member.

14. An alarm system including a latch mechanism, said latch mechanism having a flexible connective member with one end capable of being anchored adjacent one of a door frame and an entrance door and the other end detachably securable to the other of said frame and said door, an alarm mechanism, sensory means extended along at least a portion of said flexible member, circuit means coupled to said sensory means for energizing said alarm mechanism upon occurrence of a malfunction in said sensory means, said latch mechanism including a keeper and an elongated keeper plate, said plate having an elongated keeper slot therein, said sensory means including an electrical continuity loop, said keeper and said keeper plate being fabricated from electrically conductive material and being electrically connected in said continuity loop, and biasing means extended along said slot for urging said keeper into electrical contact with said keeper plate as it is moved along said slot.

15. An alarm system including a latch mechanism, said latch mechanism having a flexible connective member with one end capable of being anchored adjacent one of a door frame and an entrance door and the other end detachably securable to the other of said frame and said door, an alarm mechanism, sensory means extended along at least a portion of said flexible member, circuit means coupled to said sensory means for energizing said alarm mechanism upon occurrence of a malfunction in said sensory means, said sensory means defining a circuit path for arming said circuit means and said circuit means including fail-safe means for energizing said alarm mechanism upon occurrence of a break in said path, said fail-safe means including a relay having normally closed contact means connected in series with said alarm mechanism and a source of electrical potential, said relay having an energizing coil capable of holding said contact open when energized, and said coil being connected in series with said path and said source.

16. The combination according to claim 15 wherein said relay includes normally open contact means connected in series with said path and said coil so that said relay is latched to an open circuit condition upon a momentary break in said path.

17. The combination according to claim 15 wherein electrical shield means are extended along that portion of said path which coextends with said flexible member, said shield means being so connected to said source that said relay coil is dropped from said circuit means when said shield means are short-circuited to said path.

18. The combination according to claim 17 wherein dropping resistance means are connected in said circuit means to said relay coil and to said shield means such that current is limited through said relay coil and said shield means both during normal operation of said coil and when said shield means are short-circuited to said path.

19. The combination according to claim 16 wherein electrical shield means are extended along said flexible member and the adjacent portion of said path, said shield means being connected to said circuit means generally in by-passing relation to said normally open contact means so that said relay is latched to an open circuit condition upon a momentary short circuit between said shield means and said path.