USRE24541E - Tape switch - Google Patents

Description

SePt- 23, 1958 I R. H. KOENIG Re. 24,541

l TAPE SWITCH Original Filed Jan. 6, 1954 United States Patent Oiice Re. 24,541 Reissued Sept. 23 195@ TAPE SWITCH Robert H. Koenig, Cambria Heights, N. Y.

Original No. 2,770,696, dated November 13, 1956, Serial No. 402,460, January 6, 1954. Application for reissue April 2, 1958, Serial No. 728,504

3 Claims. (Cl. 200-86) Matter enclosed in heavy brackets I: appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

This invention relates to electrical switches and more particularly to electrical switches having a continuous tape-like form and adapted to b e actuated by the weight of a person or vehicle passing over it.

Conventional pressure type strip switches generally have a plurality of spaced insulators and this plurality of parts limits the operability and reliability since they are non-homogeneous in nature and therefore operate differently at dilferent points along their length.

Another problem with conventional switches of this type is that it is not feasible to bend them around corners or to coil unused portions into a small radius since this tends to short circuit them.

Conventional strip type switches rely on the iiexibility of the rubber sheathing for mechanical functions beside-s offering protective covering to the switch. They therefore are not as rugged and durable as the switch of the present invention which could operate without the rubber jacket.

The present invention comprises an electrical switch having a pair of spaced continuous conducting strips having a slight -transverse concavity. The two conducting strips are spaced .apart by two smaller strips of insulating material and the whole assembly is covered with a rubber or plastic jacket. The finished product looks very much like an electric cable except that it has an extremely iiat cross section.

In operation, the strip is laid on the ground and anything pressing down on it such as the wheel of a car or a persons foot will atten the upper conducting member so that it touches the bottom, thereby making the switch contact.

The invention can be successfully manufactured in any length with a single strip for each conductor, however it is desirable to construct one of the conducting strips of overlapping segments to prevent buckling of the inner conductor when the tape switch is coiled. Because the conductors take different radii when coiled, one of them must be made extensible or compressible in length to prevent buckling and consequent damage to the plastic jacket. A simple and satisfactory -construction of the segmented conductor is shown. Y

The segmentation of one conductor is required only where the tape switch is to -be made coilable. Where short lengths are to be manufactured for example, to form a switching floor mat, this segmentation is not necessary.

A primary advantage of the present invention is that it can be easily manufactured at low cost and it can be covered simply by plastic strips sealed at the edges or by conventional cable covering extrusion process.

Another advantage of the present invention is that the functional part of the switch is in itself a rugged and encased strip which will operate independent of any protective jacket. Because of this construction it is not subject to short circuits caused by metallic chips piercing the plastic jacket, a common fault of other types.

Accordingly, a principal object of the invention is t0 provide reliable and improved electrical switch means.

Another object of the present invention is to provide new and improved electrical switch means of the type adapted to be actuated by foot or vehicular pressure.

Another object of the present invention is to provide new and improved tape switch which is homogeneous and continuous in action.

Another object of the present invention is to provide new and improved tape switch which may -be coiled intov small radii or bentwithout short circuiting it. Another object of the present invention is to provide a heretofore constructed.

Another object of the present invention is to provide' a new and improved tape switch which is extremely rugged and durable and easy to manufacture.

These and other objects of the invention will be apparent from the following specifications and drawings of which:

Figure 1 is a cross sectional view of an embodimentl of the invention.

Figure 2 is a cross sectional view shown in contacting position.V

Figure 3 `is a cross sectional View shown coiled position. p

Figures 4 kand 4A' are detailed views vshowing an embodiment of the invention having overlapping leaves in one contacting member.

Switches of the present type may be used for burglar in bent or alarm systems, for actuating automatically operated doors,-y for timing, detecting or counting vehicles, and other simif lar purposes.

Figure 1 shows a cross sectional view of an embodiment of the invention. lt comprises two continuous conducting strips 1 and 2, the strips having slight transverse curvature so that they are arched away from the licor level. The conducting strips are separated by strips of insulating material 3 and 4 which are placed between the conducting strips and along the outer edges thereof.

The strip and insulator assembly rests on another insulating strip 5 and the entire assembly is covered by a weather proof jacket 6 of rubber or plastic.

The conducting strips are preferably made of -a metal having resilient or springy characteristics, for instance, spring steel or a copper alloy such as beryllium copper. The conducting strips should be liexible and are approximately one-half inch wide, and can be as thin as .005 inch.

In many applications, it is necessary to bend the tape around the corners -or over curb stones and the like, so that the assembly of the conducting strips and the separating insulating material should be fairly flexible. In many applications, for instance, those of a temporary nature, the length of switch tape available will be too long for its intended use and it is therefore, necessary that the tape switch be adapted to be coiled up in a convenient manner without short circuiting the switch.

The spacing insulators 3 and 4 may be of any insulating material which is sufficiently flexible such as rubber or a plastic. The outer jacket 6 is preferably of rubber or a flexible plastic which is resistant to water, oil and abrasion and which is generally weather proof. The purpose of this is that the tape switch may be used outside, for instance, on roadways in making a tratiic survey or at gas stations to give notice of an entering car. Because of the transverse curvature of the tempered metal strips and the unique restoring properties of such yconcaval strip, it is practically impossible to deform it permanently. The tape switch may be made quite thin so that it will hardly be noticeable even when stepped on and would not transmit any bumps to a passing vehicle,

3 O neleightliinch-overall thickness is typical for this dimension.

Figure 2 shows a cross sectional view of the invention in the deformed or contact rnaking position. When a weight isplace'd on top of the switch, the upper conduct-ingvstrip- 1' is temporarily attened toca-use itto come in= contact with the lowerconducting strip 2, thereby establishing-an electricall circuit which may be' used for anyv purpose desiredt Figure 3 showsthe position -of the respective members whenV the tapel switch is bent or coiled. In this condition, the conductor members 1 and 2 are substantially parallel, becausefitY is they nature ofthe concave strip to lose all transverse concavity when rolledA into a coil'. This useful property permits bending` or coiling'the tape switch into Iextremely sharp radii Without short circuitplurality of lengths of the tape switch may be laid side by vside to formA a--mat to-providewide enough coverageso that it may not-be'stepped over.

Figures 4 and 4A show details of the overlapping leaves which may be used inl one or both of the conductor strips to prevent buckling of that conductorv when coiled.

Figure 4A shows an individual segment 10, and Figure 4V shows ysegments 11,` 12, 13, etc. in overlapping relation.

The purpose of the notches 15, 16, etc. is to prevent shorting out. A- short circuit` would most likely arise at the center of the free ends as the tape switch is bent, since the edgesl are held by the edge insulating strips. Therefore, these free ends are notched to avoid this possibility. The center fingers 14 are merely the result of notching.

Iclaim:

1. An electrical tape switch adapted to be coiled like strips being axially stretched and the inner of said strips being axially compressed.

2. An electrical ta'pe switch having a pair of uniform conductive membersv [each] at least one having a slight 4 transverse curvature [concave in the same directionI, and

' conducting strips [having a vslight transverse 'curvature],

means to mount said strips inspaced relationship, including means to insulate said members from each other wherein at least one of said conducting" strips' comprises, axially segmented slidableoverlapping contacting.- leaf.- members adapted to permit coiling and bending of said tape switch, without shorting or damage due to buckling. 3. Apparatus as in claim 2 wherein said leaf members are notched at one end to lessen thepossibility of shorting at sharp bends.v

References Citenl in the le of this patent or the original patent UNITED STATES PATENTS 774,436 Johnson Y -.v-.. ...s Nov. 8, 1904 1,725,963 Aug. 27, 1929 1,950,490 2,361,826 Dowden a Y v Oct'.v31, 1944 FORIGN PATENTS 402,446v Great Britain. .r ....fn A- .Nov. 30;- 1933y

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