US3569645A

US3569645A - Tamperproof switch devices for burglar alarm systems, affording cordless connections across protected station separations

Info

Publication number: US3569645A
Application number: US771390A
Authority: US
Inventors: Lawrence N Lea
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-10-29
Filing date: 1968-10-29
Publication date: 1971-03-09
Anticipated expiration: 1988-03-09

Abstract

The fundamental switch unit interposed in a conductor included in the circuit, comprises a permanent magnet carried for example on a door, and an armature carried on a door frame, so when the door is closed, the magnet attracts the armature thereto into contact therewith, thus providing a current path through said conductor. Said switch components are relatively movable from a normal rest position, independent of door movement. Use of two switch units eliminates need of a door cord. Use of four units can serve to break the lead-in and the leadout wires at the protected opening. With a small addition, a unit can include a normally closed switch, which assembly can serve in protective circuits which are either or a combination of open and closed circuit systems.

Description

United States Patent [72] Inventor Lawrence N. Lea

(1683 University Ave., Bronx, N.Y. 10053), 1*: Y? [21] Appl. No. 771,390 [22] Filed Oct. 29, 1968 [45 1 Patented Mar. 9, I971 [54] TAMPER-PROOF SWITCH DEVICES FOR BURGLAR ALARM SYSTEMS, AFFORDING CORDLESS CONNECTIONS ACROSS PROTECTED STATION SEPARATIONS 2 Claims, 20 Drawing Figs. [52] US. Cl. 200/6l.62, ZOO/61.93, 335/205 [51] Int. Cl. H0111 3/16 [50] Field oi'Search ZOO/61.93, 61.62; 340/274; 335/205, 206; ZOO/51.09, (inquired); 339/12 (Digests); 335/207 [56] References Cited UNITED STATES PATENTS 2,234,982 3/1941 Ross 339/12X 200/6162 2,924,682 2/ 1960 Winterburn 3,087,145 4/1963 Fruh 200/6193 3,014,104 12/1961 Cobine et al 337/90 FOREIGN PATENTS 128,831 8/1948 Australia 339/12 Primary ExaminerRobert K. Schaefer Assistant Examiner-M. Ginsburg Attorney-MD. Nissenbaum ABSTRACT: The fundamental switch unit interposed in a conductor included in the circuit, comprises a permanent magnet carried for example on a door, and an armature carried on a door frame, so when the door is closed, the magnet attracts the armature thereto into contact therewith, thus providing a current path through said conductor. Said switch IAMFEMOOF SWITCH DEVICES FOR BURGLAR ALARM SYSTEMS, AFFGING (20 LESS GGNNECTIGNS ACROSS PIRG'IECTED STATION SEPARATIGNS The present invention relates to magnetic switches adaptable for use especially in the protective circuits of burglar alarm systems.

Magnetically operated switches have been in use in conjunction with doorways and windows. Broadly described, they comprise a stationary casing containing a switch mechanism, mounted on the frame of the door or window, and a permanent magnet structure to be mounted on the door, window sash or other movable member; the magnet being so located on the movable member that the switch mechanism is actuated thereby when the movable member is in closed position. However if the said member is moved out of the predetermined relationship with respect to the switch mechanism, by opening the movable closure member, the switch mechanism is released to actuate an alarm circuit.

The magnetic switches heretofore available, used the magnetonly as an operating influence to effect switch manipulation. The magnet conducted no current and was no part of any electrical circuit.

The principal object of this invention is to provide novel and improved switch constructions which are magnetically operated, and by utilizing the magnet to be part of the switch itself besides its operating member, so it is current-carrying in the switch circuit, such new switches which are the subject of this invention, as compared with magnetic switches heretofore known, are very simple in structure, and much lower in cost to manufacture, and further, offer uses and functions of which the old types were incapable.

Another object of this invention is to provide novel and improved magnetic switch constructions of the character mentioned, which connect into the circuit, conductors as for instance metallic tape arrangements carried on the glass of doors and window sashes; such connections being effected when such movable closure is in closed position, but disrupted when the door or window is opened; such connections being made and undone by the switch means per se, thus avoiding the need of door or window cords.

A further object thereof is to provide novel and improved magnetic switching means which will at each protected opening in a burglar alarm system, make connection of the incoming positive and negative leads and the outgoing positive and negative leads when the closure member is moved to closing position, and which will open such positive and negative connections when the closure member as the door or window are moved to open condition.

A further object thereof is to provide a magnetic switch combination in which one of my new switches is associated with one of the old type, utilizing'a single magnet for their simultaneous operation, adaptable in protective systems having both normally open and normally closed protective circuits.

Another object is to so construct my new switches that exposed moving parts are recessed when the moving closure member is in open position, so as to avoid any damage thereto.

Another object is to provide switches of the character described, which remain in effective operative condition in installations subject to vibrations, chatter and flutter within normal limits, or where there is some undue space in instances 1 where the closure and its frame are ill-fitted, due to a dimensional fault or because of warping.

A further object is to provide magnetic switch constructions of the type set forth, which essentially comprise two parts to be mounted as heretofore, one part on the closure, and the other on its stationary frame, or such parts may be mounted respectively on the parts of one movable closure, as the sashes on a window frame, or the meeting panels of a twin sliding door construction; the difference being that the magnetic component is part of the switch itself, connected in such manners in the circuit, that my new switches have a new mode of operation or function, in that way they carry current across the parting of the protected movable member and its'frarne, or across the parting of relatively movable members, when the closure is in closed position.

A further object is to provide that the switch components have attaching structure so that they may be mounted that their parting plane may be either horizontal or vertical, to best suit the structure on which they are used.

Still another object thereof is to provide novel and improved magnetic switches having the attributes above stated, and which are efficient in carrying out the purposes for which they are designed.

Other objects and advantages will become apparent as this disclosure proceeds.

For the practice of this invention, the preferred embodiment of the fundamental switch device unit, any number of which are combined in convenient entities to suit the particular needs and required functions of various installations, is comprised of a permanent magnet element on a dielectric mounting member adapted to be appropriately affixed to the closure member of an opening which needs to be protected, and an armature elemennon a separate dielectric member adapted to be appropriately afiixed to the frame member of said opening, to be so arranged that when the opening is in closed condition, the magnet faces and attracts its armature from a retracted position, into contact therewith, thus providing a current path; each mounting member presenting a binding post connected to the switch element it carries. A switch device constituting two such switch units, eliminates the need of door cords and the like, and in a setup of four such switch units, may function when the protected opening is in open condition, to break both lead-in wires and both leadout wires. A basic unit may be provided with a simple addition to include a normally closed magnetic switch,so the assembly can serve in protective circuits using combined open and closed circuit systems.

In the accompanying drawing forming part of this specification, similar characters of reference indicate corresponding parts in all the views. FIGS. 1A and 1B are perspective views of the respective cooperating parts constituting a preferred form of switch device embodying teachings of this invention.

FIG. 2A is a fragmentary longitudinal central section of the switch part shown in FIG. 1A.

FIG. 2B is a fragmentary longitudinal central section of the switch part shown in FIG. 18.

FIGS. 3A and 3B are perspective views of the respective cooperating parts constituting a modified form of switch device embodying teachings of this invention.

FIG. 4A is a fragmentary longitudinal central section of the switch part shown in FIG. 3A.

FIG. 4B is a fragmentary longitudinal central section of the switch part shown in FIG. 3B.

FIG. 5 is a diagrammatic representation of the switch device comprising the parts shown in FIGS. 3A and SE, to be utilized in a circuit in a special manner, as will be explained.

FIGS. 6A and 6B are perspective views of the respective cooperating parts constituting a switch construction which is a combination essentially of the switches set forth in the FIGS. 1A, 1B and 2A, 2B.-

FIG. 7 is a diagrammatic representation of the switch device comprising the parts shown in the FIGS. 6A and 68, to be utilized in a circuit in a special manner, as will be explained.

FIGS. 8A and 8B are perspective views of the respective cooperating parts constituting a switch device, like that of FIGS. IA and IE, but of slightly modified construction. In

fact, FIGS. 18 and 8B are identical.

FIG. 9 is a fragmentary view, partly diagrammatic, showing a switch construction of the type IA, 113, utilized in the protective circuit of a burglar alarm system, where the closure of the protected opening is a door having a taped glass pane.

FIG. I0 is a similar view, where the closure of the protected opening is a double-sashed window, whose panes are taped.

FIG. II is also similar view, where the closure is a venetian blind.

FIG. 12 is an enlarged perspective view of the preferred permanent magnet piece utilized in these switch devices.

FIG. 13, is an enlarged perspective view of the shell serving herein as an armature, in several embodiments of the switches herein illustrated.

FIG. 14 is a fragmentary view of a circuit diagram of a burglar alarm system, showing another modified switch construction in accordance with this invention, utilized in a specific manner which will be explained. In the drawing, the numeral 15 designates generally the magnet-holding part of a switch device, and the numeral 16 designates generally its companion armature-holding part. The magnets '17, 17, are recessed flush in spaced relation as inlays in a wall 18 of an oblong plastic casing 19, having integral pierced

tabs

14, 14' and 20, 20 to enable said casing to be appropriately mounted, and there is a plastic cover plate 21 which is attached by means of the eyelets 22. The magnets are preferably permanent U-magnets, each comprising a tubular piece counterbored at one end and slitted at 23 to offer north and south poles 24, 25. The head of a brass bolt 26 sits in the counterbore 27, and a nut 28 holds the magnet in place as well as a conductive connection 29 to an external binding post. The binding post connected to magnet 17 is at 30, and the one to the magnet 17' is at 30'. These binding posts are shown on one casing wall which is adjacent the wall 18, but they may be positioned elsewhere on the easing, as for instance, one on each of the end walls 31 and 31' respectively.

The plastic casing 19 is substantially of the same outside appearance and dimensions as 19, having similar attachment tabs and cover, but it provides the tubular guides 32 to slidably hold the

armatures

33, 33 for said magnets 17 and 17' respectively. Each armature is an iron shell having an outward flange as 34 at its rim, which acts to limit the extent of outward movement of the armature when attracted by its related magnet. Each arrnature is spring-biased to retract into the casing 19', to be a bit recessed in the wall 35, which is its rest position caused by the coil spring as 36, one end of which is anchored in a lug 37, and its other end is anchored to a metal piece 39 which connects to a binding post. The armature binding posts are indicated at 38, 38' respectively, on the wall corresponding to that presenting the

binding posts

30,30.

It is evident that the switch device comprising the

parts

15 and 16, constitute a normally open, double-pole single-throw switch, which is adaptable for use in protective circuits which for example are illustrated in FIGS. 9,10 and 1-1. In FIG. 9, such switch device is interposed in the protective circuit 40, to protect the door 41, whose glass pane 42 is provided with the metallic tape 43; the ends of said tape being connected across the terminals 30, 30' of part 15 which is mounted immediately below the top edge of the door, while one lead-in wire is connected to the terminal 38 and the other lead-in wire is connected to the terminal 38 of the part 16 which is mounted immediately above the top rail of the door frame 44. The arrangement is such that the magnets are directly opposite the armatures respectively and contact them respectively, when the door is closed. Should the door be opened while the system is in operative condition, or should the tape be broken while such operative condition exists, there would occur a break in the protective system, and thus sound the alarm. Since the switch device offers a path for the current across the separation of the door and its frame, no door cord is necessary.

In FIG. 10, two such switch devices are interposed in the protective circuit 45, to protect the double-sash window 46, whose lower pane 47 has a loop 48 of metallic tape thereon, and whose upper pane 49 has the separate tapes 50, 50' thereon, as shown. The ends of the loop 48 are connected to the respective terminals of a switch part 15 mounted on the upper rail of the lower sash. The lead-in wires are connected respectively to a switch part 16 mounted on the top rail of the window frame 51. The lower ends of the

tape parts

50, 50 are connected to a switch part 16 mounted on the bottom rail of the upper sash, and the upper ends of said tape parts, are connected to a switch part 15 mounted on the upper rail of the upper sash. Companion switch parts are of course, positioned to cooperate as mentioned. It is evident that upon movement of any of the sashes, or upon the breaking of any of the tapes on the panes, that the alarm will be sounded.

In FIG. 11, one such switch device is used to protect against the lifting of a Venetian blind 52. The lead-in wires of the protective circuit 53 are connected to a switch part 15 which is mounted on the windowsill 54. A companion switch part 16, mounted on the bottom rail 55 of the blind, has its terminals shunted by a conductor 56. It is evident that upon the lifting of the blind, there will occur a break in the protective circuit, and so the alarm will be sounded.

It is to be noted, that the recessing of the armatures is to avoid any interference from them with the movement of the closure member to closing position. Normal flutter or vibration of a door or window protected by these switch devices, will not undo the contact of the magnets with their armatures. The possible scope of armature movement, should be sufficient to span any normal spacing between the

casing

19, 19 caused by ill-fitting doors and sash frames.

The switch device constituting the companion parts shown in FIGS. 3A and 38, includes only one magnet 17"and its armature, which is here shown to be a slidably mounted pin whose head 57 faces said magnet when the device is installed, to be attracted thereto for contact therewith. Said armature being biased by a coil spring 36' to a recessed position in the casing wall. This armature has an integral arm 58 which is normally in contact with a metal cantilever bow spring 59 mounted within the casing as shown. The numeral 60 designates the binding post connected to the magnet. The numeral 61 denotes the binding post connected to the armature, and the numeral 62 indicates the binding post connected to the bow spring. The casing structures follow generally those of the device of FIGS. 1A, 1B. This switch device of FIGS. 3A,3B, offers a normally open switch whose terminals are 60 and 61, and a normally closed switch whose terminals are 61 and 62, each of which individual switches find uses in burglar alarm circuitry as is well known in this art. As a commercial article, it is most practical to have an embodiment which can be utilized in all manners afforded by both switch devices of 1A, 1B and 3A 38. Such combination is the makeup OF the switch device shown in FIGS. 6A,6B, wherein the magnets are denoted by the numerals 63, 63' whose binding posts are 64, 64 respectively. Their armatures are indicated by the

numerals

65,65, whose binding posts are 66, 66 respectively. The binding post for the bow spring 67, is designated as 68.

The magnet-carrying switch part shown in FIG. 8B is identical with the one shown in FIG. 1B. The switch part of FIG. 8A which is the companion part carrying the armatures, shows such armatures as

cantilever spring blades

69,69, normally positioned in the channel 70; their binding posts being denoted as 71, 71' respectively.

The fundamental switch comprising a permanent magnet on one part, and an armature therefor on another part; said parts to be mounted on relatively movable members, or entities embodying a plurality of magnets on one part and armatures on the other part to cooperate therewith respectively, find many uses in the burglar alarm art. In some protective systems, it is desirable to break both lead-in wires and both leadout wires at protected openings when the closure member associated with said opening is in open condition. To accomplish this, there may be a protective switch device whose cooperative parts numbered 72 holding four permanent magnets, and 73 holding their companion armatures, are installed in a protective circuit, one switch part being mounted on the frame of the opening and the other switch part being carried by the closure member associated with said opening. Two such quadruple switch constructions are shown employed in the protective circuit 95, at successive protected stations respectively in a building, as indicated in FIG. 14. The lead-in

wires

74, 74 to one switch device, are connected to the terminals of two armatures. The leadout wires 75, 75' are connected to said one switch device, across the terminals of the other two armatures. The binding posts of those magnets which are companions of one lead-in wire and one leadout wire, are connected by a conductor 76. The binding posts of the other magnets are connected by a conductor 77. When the armatures are attracted to their respective magnets and in contact therewith respectively, the current path is established. When the closure associated with the switch device 72,73 is in open condition, there is a break in each lead-in wire and in each leadout wire. The second identical switch device designated generally by the numeral 78, has for its lead-in wires, the

wires

75, 75'. if the connected magnets are alternate ones in each of the switch devices respectively as in FIG. 14, then the plus and minus terminals are in the same sequence in both switch devices, and this scheme being followed where possible at succeeding stations protected, installation is facilitated and same serves as a help for making repairs, because lead identity is established.

Single switch units, comprising a magnet carried on one part and its armature on a companion part, may be used as a trip switch by using two such single switch units in conjunction with a conductive trip cord. One part of each such switch structure being affixed on opposite baseboards in a room respectively, their companion parts are connected, one to each end of the cord. it is believed that this is readily understandable to those versed in the art, without the necessity of further illustration.

The function of these switches taught herein most serviceable, is to provide for current to have a path spanning the space between an opening and its closure member, without the use of a door cord and the like. So as in FIG. 9 for instance, where one

switch

15,16 offers a path for current from the doorfrarne onto the door, it is believed readily understandable that by the use of an additional similar switch device, akin to the use made with the tape on the upper sash, the current path can be made to cross over from the door back onto the doorframe, and continue to the next protected station in the protective system. In view of the showing of accomplishment of leading a current first to the upper sash from the window frame in H6. lit), and then from said upper sash, across to another member, it is believed that these versed in this art, will readily understand the above, without the need of further illustration.

Essentially, the switch unit taught herein is a bridge to carry current and to connect that part of the protective circuit structure which is on the protected openings frame with that part of the protective circuit structure which is on the movable closure member. All this is in addition to the switches function to protect the opening, for which the switch 1A, 18 can be used alone where there is no protective circuit structure on the clo sure, as for instance where there is no tape protecting a glass pane. in such instance the terminals 30, 30' are connected by a conductor as shown at in FIG. 7. These switches are tamper-proof, for even if for instance a transom pane is broken, or if it be an unprotected pane that is broken to gain access to the switch, the application of a strong magnet to part 16, will not keep the switch closed, nor would the insertion of a blade between 15 and 16 keep the switch closed, because as soon as the closure member as the door, is opened, the

armatures

33, 33 will be retracted by action of the springs 36, and thus become separated from the blade.

This invention is capable of numerous forms and various applications without departing from the essential features herein disclosed. it is therefore intended and desired that the embodiments shown herein shall be deemed merely illustrative and not restrictive.

l claim:

1. In a switch device comprising two switch units interposed in a conductor means included in the circuit of a burglar alarm system protecting a frame member having a movable closure member, said device consisting of a permanent magnet element for each switch unit respectively, mounted on the closure member and insulated therefrom, a dielectric casing mounted on the frame member, an armature element for each magnet element res ectively, positioned recessed within the casing, at a rest post ion therein from which it is movable, and

spring means within the casing, biasing each armature element to its rest position; said casing being open so said armature elements are movable outwardly to protrude from the casing whereupon said spring means are stressed; said elements being electrically conductive said conductor means being in two parts which are entirely off the closure member and connected respectively to the armature elements; the magnet elements being connected by a conductor positioned entirely on the closure member; each magnet element facing its related armature element when the closure member is in closing position, whereupon the attraction between each magnet element and its related armature element will cause each armature element to come out of said casingand into contact with its related magnet element thereby forming a current path connecting said parts of the conductor means whereby current can flow therethrough.

2. A switch device as defined in claim 1, including a conductive piece mounted in said casing, a conductive arm extending from'one of said armature elements and contacting said conductive piece whereupon movement of said one armature element when the closing member is in closing position, said arm will be moved away from said conductive piece, and binding posts conductively connected with said conductive piece, said armature elements and said magnet elements respectively.

Claims

1. In a switch device comprising two switch units interposed in a conductor means included in the circuit of a burglar alarm system protecting a frame member having a movable closure member, said device consisting of a permanent magnet element for each switch unit respectively, mounted on the closure member and insulated therefrom, a dielectric casing mounted on the frame member, an armature element for each magnet element respectively, positioned recessed within the casing, at a rest position therein from which it is movable, and spring means within the casing, biasing each armature element to its rest position; said casing being open so said armature elements are movable outwardly to protrude from the casing whereupon said spring means are stressed; said elements being electrically conductive ; said conductor means being in two parts which are entirely off the closure member and connected respectively to the armature elements; the magnet elements being connected by a conductor positioned entirely on the closure member; each magnet element facing its related armature element when the closure member is in closing position, whereupon the attraction between each magnet element and its related armature element will cause each armature element to come out of said casing and into contact with its related magnet element thereby forming a current path connecting said parts of the conductor means whereby current can flow therethrough.

2. A switch device as defined in claim 1, including a conductive piece mounted in said casing, a conductive arm extending from one of said armature elements and contacting said conductive piece whereupon movement of said one armature element when the closing member is in closing position, said arm will be moved away from said conductive piece, and binding posts conductively connected with said conductive piece, said armature elements and said magnet elements respectively.