US 3409886 A
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Nov. 5, 1968 H. B DAVIS ET AL. 3,409,886
BURGLAR ALARM SYSTEM INCLUDING PROTECTIVE TAPE Filed Dec. 26, 1967 INVENTORS HAROLD B. DAVIS RICHARD G. TERKER ATTORN YS United States Patent 3,409,886 BURGLAR ALARM SYSTEM INCLUDING PROTECTIVE TAPE Harold B. Davis, Flushing, and Richard G. Terker, Scarsdale, N.Y., assignors to Security Tape Corporation,
Flushing, N.Y., a corporation of New York Filed Dec. 26, 1967, Ser. No. 693,518 Claims. (Cl. 340273) ABSTRACT OF THE DISCLOSURE An alarm system using a continuous non-interrupted conductive strip, any disruption thereof producing an alarm response, a protective covering over said strip comprising a tape continuous with and overlying said strip, the central portion of the tape being free of any adhesive and directly covering the strip, the outer portions being coated with a pressure-sensitive adhesive and disposed to adhere to the strip supporting surface.
BACKGROUND OF THE INVENTION Field of the invention A burglar alarm system including a physically weak conductive strip on a supporting surface, the tape being covered by a protective strip.
D scription 0 the prior art Burglar alarm systems conventionally use means which if interrupted produces a discontinuance of a particular function, such as an interruption of current, voltage, light or some mechanical movement of a kind and nature to produce an indication, be it visual, audible or otherwise, so as to show or indicate that something has occurred to interrupt the status quo.
One widely used burglar alarm system utilizes a simple continuous conductive strip in the form of a thin elongated electrically conductive foil applied to a window, door or any areas susceptible to entry. The foil strip is usually a very thin soft lead/tin alloy which has very little strength either in shear or tension and thereby tears and breaks very easily. This is necessary so as to permit any wrongful action against the area carrying the foil to create a condition whereby the tape will break or tear quickly. However, under accidental circumstances where someone or something brushes up against the foil, the same will rupture and cause an alarm to be actuated. There are many occasions where this will occur, and the repetition of such ruptures becomes costly, not only from a repair point of view, but because the objective of the alarm system is momentarily disrupted or frustrated. Indeed, thieves intending to burglarize a store make it a practice deliberately to break the foil near closing time when it is too late in the day to effect a repair.
There have been occasions whereby a protective tape with a full width pressure adhesive face was applied to the foil, but this, because it adhered to the foil, reinforced the foil to a point where any break or crackin the support carrying the foil failed to break or rupture the foil. Further, when removing such a protective tape for any purpose it caused the foil to rupture or become dislodged from the support base; hence, there was no real apparent advantage of such type protective tapes.
SUMMARY OF THE INVENTION The primary object of the invention is to provide an improved type burglar alarm system.
Another object of the invention is to provide an alarm system which requires less repairs, has fewer breakdowns and costs less to maintain.
3,409,886 Patented Nov. 5, 1968 BRIEF DESCRIPTION OF THE INVENTION FIG. 1 shows a diagram of the burglar alarm system and tape according to the invention;
FIG. 2 is an enlarged section through the line 22 of FIG. 1; and
FIG. 3 shows another embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in detail to the drawings illustrating the preferred embodiments by which the invention may be realized, there is shown in FIG. 1 a base or window-like panel 10 of a window or door. Said panel forms at least a part of a wall of an enclosed space. The panel is to be protected against entry into the space as by breaking the panel. On the space side of the panel reposes a continuous electrically conductive strip 12 arranged in a desired pattern selected to provide maximum burglary protection and series connected to a relay coil 14 which forms part of a relay 16. A source of electric potential 18 in the series path including the conductive strip completes the said path to form a first series circuit for the purpose of continuously energizing the relaycoil 14. A second conductive series circuit comprises a pair of normally closed contacts 20 of the relay 16, a pair of manually operated contacts 22, an electrically operable alarm such as a'bell 24, and a source of electric potential 26. The contacts 20 are held open as long as the relay coil 14 is energized. The contacts 22 are closed by the lessee, manager or owner of the premises. A break in the energizing circuit for the coil 14 causes the contacts 20 to close and form a continuous closed series loop, thereby energizing the alarm bell 24.
The conductive strip 12 arrangement, a section thereof being shown in FIG. 2, comprises in more detail a glass base 28 upon which a film-like layer of varnish 30 is coated and thereover a lead/tin alloy foil conductive fragile strip 32 is placed, the foil being suitably adhered to the supporting base 28 by the varnish film layer 30. Another varnish layer 34 is coated over the foil 32 to complete the adherence of the foil to the glass plate or base support. As thus far described, the burglar alarm system is old.
Pursuant to the present invention, an outer covering tape 36 is made to overlie the foil in a manner so arranged as to provide a protective covering for the fragile lead/ tin foil strip, but not to desensitive the foil to breaking or cracking of the support 28.
In particular, the overlying protective covering tape 36 comprises a suitable flexible plastic, e.g., polyvinyl chloride, narrow web 38 coated with a pressure sensitive adhesive strip 40 only along the outer marginal longitudinal areas or zones 42 of the web, the central area 44 being devoid of any adhesive element. Said central area 44 is disposed to cover and contact the film conductive foil strip 32 or that portion of the varnish layer 34 which overlies the same, if such layer is used. However, said foil strip or the part of the varnish layer overlying the same is not contacted by the outer marginal adhesive areas 40. Thus, the only portion of the protective covering which contacts the foil or the portion of the varnish layer which overlies the same is the central part 44 that is devoid of adhesive. Desirably, the width of the non-adhesive central void 44 is wider than the fragile lead/tin alloy strip 32, e.g., about /2 inch wider, so as to make it easier to apply the tape to the foil strip without adhesively contacting the foil strip or the part of the varnish layer overlying the same.
It will be apparent that the tape 36 provides protection for the underlying fragile lead/tin alloy strip 32 by virture of the inherent strength of the plastic web composing the tape. The tape is of conventional thickness, for example, in the order of 0.002 inch and, as is well known, offers a high resistance to rupture or cutting, except with an extremely sharp instrument, particularly when the tape is adhered to a supporting surface such as a pane of glass. Thus, the tape is not likely to be torn accidentally as when it is brushed by a part of a shopping cart or by a piece of furniture or other hard object having corners or edges. Indeed, the tape is not likely to be broken even when a burglar deliberately draws a handheld instrument across the tape in a casual manner not designed to attract the attention of an employee of a store. Thus, the tape has been found to provide excellent protection against accidental breakage of or even deliberate attempts to break the tape, so that a burglar alarm system so equipped is not likely to sound an alarm often, nor is it prone as is existing systems to be deliberately broken near the end of the day by a burglar who intends to make a hit that night because the system would then have been turned oif and the burglar alarm service would not have had an opportunity to repair the break before the store closed. However, despite this excellent protection afforded b the tape, it in no .way renders the system less sensitive to burglarous entry. Because the tape, although it contacts the fragile lead/tin alloy strip, does not adhere to the strip or the part of the varnish layer overlying the same, it does not strengthen the strip visa-vis its underlying glass support. Hence, when this glass support is cracked or broken, the strip will be ruptured concurrently with the impairment of the glass, as it would not be if the strip were adhered to the protective tape which in such case might keep the foil strip whole despite destruction of the support. It also will be observed that because of the non-adherence of the protective tape to the foil strip directly or through the part of the varnish layer overlying the same, it is possible to pull the protective tape away from the underlying glass support without breaking or tearing the underlying foil strip or delaminating it from the glass support. Due to this arrangement it is therefore possible to repair a broken foil by removing the protective tape and patching up the foil without, in the removal of the tape, further destroying substantial lengths of the foil strip.
Although what has been shown and described with respect to FIG. 2 is a covering tape 36 where the base has a central area to which no adhesive has been applied in order to render the same non-adhesive, it is possible to have a pressure-sensitive adhesive completely coated over the entire undersurface of the tape and thereafter place over that area, previously referred to as the void or nonadhesive area, a narrow non-adhesive tape in order to render the protective tape centrall non-adhesive. As shown in FIG. 3, according to such alternate embodiment of the invention, the protective covering 46 comprises a thin base web 48 of a flexible plastic, e.g., polyvinyl chloride, coated with a pressure sensitive adhesive over an entire surface 50 thereof, and along the central part another narrower non-adhesive flexible tape 50, e.g., of Mylar (a polyester) is centrally placed and adhered so that marginal sides 54 of the base 48 overhang (protrude laterally away from) the central non-adhesive tape 52. The protective covering 46 is then made to overlie the fragile lead/tin foil that is adhered to a glass support in an orientation such as to permit only the non-adhesive tape 52 to make protective contact therewith or with the part of the varnish layer overlying the same while the extending sides are made to adhere to the glass foundation.
While the invention has been described and illustrated with respect to certain preferred embodiments which give satisfactory results, it will be understood by those skilled in the art, after understanding the principles of the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention and it is therefore intended in the appended claims to cover all such changes and modifications.
Having thus described the invention, there is claimed as new and desired to be secured by Letters Patent:
1. In an alarm system including a continuous electrically conductive path whose disruption is disposed to produce an alarm indication, the combination comprising;
(a) a panel of an enclosed space to be protected against unauthorized entry,
(b) a fragile metallic foil mounted to the space side of said panel, so that it will break when the panel is broken or cracked, said foil forming an elongated continuous electrically conductive path,
(c) covering means over said foil and including outer extremities overhanging said foil along its elongated path and disposed to adhere to said base,
((1) the center of said covering means between the side edges thereof and overlying the foil being nonadhesive, and
(e) means connected to said foil to render an alarm upon the disruption thereof.
2. An alarm system according to claim 1 wherein said covering means includes a plastic tape having a pressure sensitive adhesive on the side margins thereof, the area between said margins being non-adhesive to provide nonadhesive contact between the foil and said area.
3. An alarm system according to claim 2 wherein the area between the side margins is devoid of any adhesive.
4. An alarm system according to claim 2 wherein the surface of the plastic tape facing the panel is covered with pressure sensitive adhesive and wherein the area between said margins is covered with a second non-adhesive narrower tape to render said area non-adhesive.
5. An alarm system according to claim 4 wherein the first-named plastic tape is composed of polyvinyl chloride and wherein the narrower second tape is composed of polyester.
No references cited.
JOHN W. CALDWELL, Primary Examiner. D. L. TRAFTON, Assistant Examiner.