US3737591A

US3737591A - Trap switch with elongated mounting wire for completing continuity circuit

Info

Publication number: US3737591A
Application number: US00192917A
Authority: US
Inventors: P Parlato
Original assignee: Alarm Products International Inc
Current assignee: Alarm Products International Inc
Priority date: 1971-10-27
Filing date: 1971-10-27
Publication date: 1973-06-05
Anticipated expiration: 1990-06-05

Abstract

A trap switch for a burglar alarm system consists of a base member adapted to be mounted on a fixed body and a movable member adapted to be connected to a movable member by an elongated flexible wire. The base member has a pair of fixed contacts biased toward one another with an access slot in the base member housing disposed in a region between the fixed contacts. The movable member has an extending insulation stab portion carrying insulated conductive surfaces on its opposite sides. The extending stab can be pressed between the fixed contacts of the base member and each contact engages one of the conducting stab surfaces. An extending wire is mechanically connected at its ends to the conductive surfaces. A continuity circuit is connected in series with the fixed contacts, and can be either normally open or normally closed depending on whether the elongated wire is conductively connected between the conductive surfaces.

Description

Parlato 11 3,737,591 14 1 June 5, 1973 [54] TRAP SWITCH WITH ELONGATED MOUNTING WIRE FOR COMPLETING CONTINUITY CIRCUIT 1 Philip J. Parlato, Kings Park, N.Y.

Alarm Products International, Inc., Long Island City, NY.

' Filed: Oct. 27, 1971 Appl. No.2 192,917

Inventor:

Assignee:

U.S. c1 ..200/61.93, 200/51 R, 200/5109, 200/163 Int. Cl. ..110111 3/02, l-lOlh 13/70 Field of Search ..200/16 E, 16 F, 51 R, 200/51.09,51;10, 51.12, 51.13, 61.19,

7 References Cited UNITED STATES PATENTS 7/1962 Appleton ..200/51.13 X 6/1950 West ..200/61.19 X 8/1965 v Bosworth et al ..200/ 163 X 10/1962 French, .lr ..200/51 R X 5/1963 Cremer ..200/5 1.10 X

Schott et al. ..200/51.09 Lea ..200/6L93 x 57] ABSTRACT A trap switch for a burglar alarm system consists of a base member adapted to be mounted on a fixed body and a movable member adapted to be connected to a movable member by an elongated flexible wire. The base member has a pair of fixed contacts biased toward one another with an access slot in the base member housing disposed in a region between the fixed contacts. The movable member has an extending insulation stab portion carrying insulated conductive surfaces on its opposite sides. The extending stab can be pressed between the fixed contacts of the base member and each contact engages one of the conducting stab surfaces. An extending wire is mechanically connected at its ends to the conductive surfaces. A continuity circuit is connected in series with the fixed contacts, and can be either normally open or normally closed depending on whether the elongated wire is 10 Claims, 5 Drawing Figures PAIENTEDJUN 5l973 3,737 5.91.

SHEET 2 BF 2 1 TRAP SWITCH WITH ELONGATED MOUNTING WIRE FOR COMPLETING CONTINUITY CIRCUIT BACKGROUND OF THE INVENTION This invention relates to switch structures, and more particularly relates to a trap'switch for use in a burglar alarm system wherein the switch has an elongated wire serving as the operator of the switch. It is known to provide two-.piece switches for burglar alarm systems in which aba'se piece carrying spaced contacts pressed toward engagement with one another cooperates with a movable piece having an elongated insulated stab. The stab is normally between the spaced contacts and holds them apart so that the circuit between the contacts is normally open. The movable part then has a BRIEF SUMMARY OF THE INVENTION The principle of the present inventionis to provide a novel trap switch with a pair of removable conductive surfaces'on the conventional insulation stab, and to thereafter use. the device actuating wire to make electrical connection between these surfaces when it is deiitQd-to use the switch in a normally closed circuit. when the conductive surfaces are removed, the insulation stab will operateas in the past. However, by .the simple modification of using a conductor for the actuating wire, and connecting this conductor between the conductive surfaces, and then bending the contact strips of the fixed housing so that they do not make contain when the stab is withdrawn, the switch can be used, ina normally closed circuit. 2 BRIEF DESCRIPTION OF THE DRAWINGS FIG". 1 is tion., I FIG. 2 is a sideelevation of the switch of FIG. 1 with :the movable member partly withdrawn to show the a top view of the novel switch of the inventhree-component stab of the invention.

FIG. 3 is an exploded perspective view of the fixed member of the switch of FIGS. 1 and 2. r

FIG. 4: is an exploded perspective view of the movable member of the switch of FIGS. 1 and 2.

FIG. 5 isa cross-sectional view of FIG, 1 taken'across the section. line 5-5 in FIG. 1 and showing the fixed and movable members disengaged for clarity.

' bET-AI D- DESCRIPTION OF THE DRAWINGS f:- Referring now to thedrawings and particularly FIGS. '1: and; 2, there is shown what will hereinafter be re- .ferredtoas the fixedswitch member and movable Switch member 11. It will be apparent that these roles could be reversed and, more broadly, it is only necessary that there be motion of one relative to the other to cause switch operation. A main continuity circuit includes conductors l2 and 13 which are connected to terminals in fixed member 10, and an actuating wire 14 is connected to movable member 11. In its most common application, the fixed member 10 will be secured to a'fixed body,'such as a windowsill, while the" wire 14 will be connected to a movable member, such as a venetian blind, such that the movable-member 11 will be withdrawn from member 10 by the operation of the venetian blind. 1

FIGS. 3 and 5 show the details of construction of fixed member 10. Thus, member 10 includes a-molded base portion enclosed by a molded cover 21. Base 20 contains

integral extensions

22 and 23 at its ends (pedestal 22 is not visible in FIG. 5) which pedestals contain through-openings which terminate in counter sunk nut openings in the bottom of base 20. Cover 21 has

openings

24 and 25 aligned with

pedestals

22 and 23 so that securing

screws

26 and 27, which hold cover 21 on base 20, can be inserted into

pedestals

22 and 23. Nuts 28 and 29 (FIG. 1), which are contained in the countersunk openings on the bottom of base 20, threadably receive

screws

26 and 27 to hold the cover 21 in position.

Base 20 is further provided withthrough-openings 30 and 31 which receive mounting screws (32 and 33 in FIG. 1) for holding the fixed member 10 in its desired position. Note that the cover 21 must be raised (and thus the movable member 11 thereon) to gain access to mounting

screws

32 and 33 so that the switch will be operated if one attempts to bodily remove the switch. Base 20 is also provided with

integral sidewall portions

34 and 35 which contain between them pedestals 36 and 37. Pedestals 36 and 37 contain

openings

38 and 39 respectively which extend to

countersunk openings

40 and 41, respectively (FIG. 5). A pair of bent phosphor bronze contact springs 42 and 43- are then provided with openings 44 and 45,-respectively, at one end and generally U-shaped bends at the other end and are connected to pedestals 36 and 37 by screws 46 and 47, respectively. Thus, screws 46 and 47 extend through the openings 44 and in

springs

42 and 43, respectively, and then through

openings

38 and 39, respec+ tively, and then are secured by

nuts

48 and 49, respectively. Note that the U-shaped bent portions of

contact springs

42 and 43 face one another, andcould normally engage one another if the U shaped portions are bent sufficiently open. v In order to allow access to the region between

contacts

42 and 43, the cover 21 contains a slot 50. Cover 21 also contains

slots

51 and 52 to allow

leads

12 and 13 to enter the fixed member 10.

Leads

12 and 13*are then connected to

contacts

42 and 43 by being secured under the heads of screws 46 and 47, respectively.

The movable switch member 11 is shown in detail in FIGS. 4 and 5. Thus, it includes molded base and molded cover 61. Base 60 contains integral

cylindrical posts

62 and 63 which support the cover 61, and further contains openings 64 and 65. The bottom of base 60 contains four countersunk openings aligned with through-

openings

66 and 67 in

posts

62 and 63, respectively, and with openings 64 and 65. These four countersunk openings receive

nuts

68, 69, 70 and 71. A

square opening 72 is formed in base 60 and receives a central stab member 73 of insulation material. Stab 73- may be secured to the sidewalls of opening 72, or may be integrally molded therewith.

Two L-

shaped brass contacts

74 and 75 are then provided with openings 76 and 77 and are inserted through opening 72 and along either side of insulation stab 73.

Note that

contacts

74 and 75 are normally insulated from one another by stab 73.

Screws

78 and 79 inserted through openings 76 and 77, respectively, and received by

nuts

69 and 70, respectively, hold the

contacts

74 and 75 in position.

Elongated wire 14, which may be an insulation covered copper wire, has its terminal ends connected beneath the heads of

screws

74 and 75, with these ends inserted through opening 80 in housing 61. Note that when wire 14 is an insulated conductor,

contacts

74 and 75 are electrically connected to one another. In some applications, e.g., with

contacts

74 and 75 removed wire14 does not make an electrical connection between

contacts

74 and 75.

The cover 61 is then provided with

openings

81 and 82 which receive

mounting screws

83 and 84, respectively, which are captured by

nuts

68 and 71, respectively, to hold the cover 61 on base 60.

The operation of the switch can now be understood from FIGS. 2 and 5. If the switch is to be used in a normally conducting circuit, or one which is continuous between

conductors

12 and 13 with movable member 11 in its closed position (with stab 73 and its

conductive members

74 and 75 in the fully inserted position between contacts 42 and 43), then the

contacts

74 and 75 are electrically connected by

wire 14'and contacts

42 and 43 are bent so that they do not touch when in their unfiexed position. Movable member 11 is then placed in its fully connected position by inserting stab 73 (and conductors 74 and 75) through opening 50 in housing 21 and between

contacts

42 and 43. There is a relatively light spring contact pressure between

contacts

42 and 74 and

contacts

43 and 75 to define a continuous circuit from wire 12, terminal screw 46, contact 42, contact 74, wire 14, contact 75, contact 43,

terminal screw 47, and wire 13.

The movement of the member mechanically connected to wire 14 easily lifts the switch member 11 away from fixed member against the light spring pressure of

contacts

42 and 43 until there is disengagement of

contacts

42 and 43 from

contacts

74 and 75, respectively. This opens the circuit between

wires

12 and 13 to initiate a suitable alarm.

In order to use the same assemblage in a normally nonconducting alarm system, the only change needed is that the

contacts

74 and 75 are removed. At the same time, the

phosphor bronze contacts

42 and 43 are bent more open to a position where they normally engage one another. In this mode of operation, insertion of insulation stab 73 between

contacts

42 and 43 simply spreads contacts 42 and 43' away from one another and out of contact. Therefore, there is not a continuous circuit between

wires

12 and 13. However, when member 11 is moved and the stab moves away from

betweencontacts

42 and 43, they will close to complete a circuit between

wires

12 and 13 to actuate a suitable alarm. Although this invention has been described with respect to preferred embodiments, it should be understood that many variations and modifications will now be obvious to those skilled in the art, and therefore, the

scope of this invention is limited not by the specific disclosure herein, but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A trap switch for a burglar alarm system; said trap switch comprising a first switch member including a first closed housing and a second switch member including a second closed housing; said first switch member including mounting means for mounting said first switch member to a first body; said seeond switch member including means for mechanically connecting said second switch member to a second-body which is relatively movable with respect to said first body; saidfirist switch member including a first pair of spaced contact members which face one another; respective terminal means connected with each of said first pair of contact members and disposed within said first closed housing;

an opening in one wall of said first closed housing; said opening disposed adjacent to the area which includes said first pair of spaced contact members; said second switch member including a second pair of spaced contact members secured to said second switch member;

bers; said insulation-member and said second pair ofcontact members defining a projecting stab; said projecting stab extending through said opening in one wall of said first closed housing and between said first pair of spaced contact members, with said first pair of contact members respectively engaging said second pair of contact members; said one wall of said first housing being disposed over said one wall of said second housing, thereby to cover the said openings in said housings.

2. The trap switch of claim 1 wherein said first pair of contact members are spring biased normally toengage one another, and wherein said second pair of contact members areremovable to define insulation surfaces for said stab, whereby a circuit is closed between said terminal means of said first pair of contact members only when said second switch member is moved to retract said stab from between said first pair of contact members.

3. The trap switch of claim 2 wherein said first-pair of contact members are elastically deformable to a condition in which they are normally engaged when said stab is removed.

4. The trap switch of claim 1 wherein said first pair of contact members are spring biased normally to be out of contact with respect to one another, and which includes conductor means connected between said terminal means of said second pair of contact members for electrically connecting said second pair of contact members, whereby, when said stab is in said position between said first pair of contact members, there is a closed circuit between said terminal means of said first pair of contact members, and whereby removal of said stab by movement of said second switch member opens said closed circuit.

5. The trap switch of claim 4 wherein said first pair of contact members of a contact spring material is deformable to a condition wherein said first pair of contact members are normally out of engagement with one another.

6. The trap switch of claim 4 wherein said means for mechanically connecting said second switch member includes a wire having its ends at least mechanically connected respectively to said terminal means of said second pair of contact members.

includes a wire having its ends at least mechanically connected respectively to said terminal means of said second pair of contact members.

10. The trap switch of claim 1, further comprising means electrically connecting said terminal means for said second pair of contact members.

Claims

1. A trap switch for a burglar alarm system; said trap switch comprising a first switch member including a first closed housing and a second switch member including a second closed housing; said first switch member including mounting means for mounting said first switch member to a first body; said second switch member including means for mechanically connecting said second switch member to a second body whicH is relatively movable with respect to said first body; said first switch member including a first pair of spaced contact members which face one another; respective terminal means connected with each of said first pair of contact members and disposed within said first closed housing; an opening in one wall of said first closed housing; said opening disposed adjacent to the area which includes said first pair of spaced contact members; said second switch member including a second pair of spaced contact members secured to said second switch member; respective terminal means connected with each of said second pair of spaced contact members and disposed within said second closed housing; an opening in one wall of said second closed housing; said second pair of spaced contact members extending through said opening in said second closed housing; an insulation member disposed between said second pair of contact members; said insulation member and said second pair of contact members defining a projecting stab; said projecting stab extending through said opening in one wall of said first closed housing and between said first pair of spaced contact members, with said first pair of contact members respectively engaging said second pair of contact members; said one wall of said first housing being disposed over said one wall of said second housing, thereby to cover the said openings in said housings.

2. The trap switch of claim 1 wherein said first pair of contact members are spring biased normally to engage one another, and wherein said second pair of contact members are removable to define insulation surfaces for said stab, whereby a circuit is closed between said terminal means of said first pair of contact members only when said second switch member is moved to retract said stab from between said first pair of contact members.

3. The trap switch of claim 2 wherein said first pair of contact members are elastically deformable to a condition in which they are normally engaged when said stab is removed.

7. The trap switch of claim 6, wherein said wire is at least partly insulation covered.

8. The trap switch of claim 1 wherein said means for mounting said first switch member is disposed within said first housing.

9. The trap switch of claim 1 wherein said means for mechanically connecting said second switch member includes a wire having its ends at least mechanically connected respectively to said terminal means of said second pair of contact members.