US3825277A

US3825277A - Mat switch

Info

Publication number: US3825277A
Application number: US00388993A
Authority: US
Inventors: C Steinback
Original assignee: Acrometal Products Inc
Current assignee: Acrometal Products Inc
Priority date: 1973-08-16
Filing date: 1973-08-16
Publication date: 1974-07-23
Anticipated expiration: 1991-07-23
Also published as: CA1027660A

Abstract

A flexible casing of electrical insulating material, having spaced top and bottom walls and a peripheral wall enclosing a pair of spaced apart electrical conductor plates. An elongated spacer strip of flexible resilient electrical conducting material is disposed between the conductor plates, the strip being secured along a longitudinally extended transversely central portion to one of the conductor plates, but insulated therefrom, by a band of insulating material. The strip includes a pair of longitudinally extending flanges at opposite edges of the strip, the flanges diverging toward the opposite conductor plate, the outer edge portions of the flanges engaging the other conductor plate. Downward movement of the top wall and top conductor plate bends one or more of the flanges, so that the flanges engage both conductor plates to close an electrical circuit.

Description

UnitedijSta teSjPaten 1 Steinback I it July 23, 1974 MAT SWITCH [75] Inventor: Clarence I. Steinbeck, Edina, Minn.

[73] Assignee: Acrometal Products, Inc., Minneapolis, Minn.

221 Filed: Aug. 16,1973

211 App]. No.:'388,993

52 11.5. C1. 200/86.n,-340'/272 s1 lnt.Cl. H01hl3/l6 58 Field of Search 200/86 R, 85 R; 340/272 [56] I References Cited I UNITED STATES PATENTS; 2,813,163 11/1957 Durbin .200/86 R 2,813,164 11/1957 Durbini. 200/86 R Primary ExaminerDavidl Sm ith, Jr. Attorney, Agent, or Firm'Merchant, Gould, Smith &

Edell I t [57] ABSTRACT A flexible casing of electrical insulating material, having spaced top and bottom walls and a peripheral wall enclosing a pair of spaced apart electrical conductor plates. An elongated spacer strip of flexible resilient electrical conducting material is disposed between the conductor plates, the strip being secured along a longitudinally extended transversely central portion to one of the conductor plates, but insulated therefrom,

by a band of insulating material. The strip includes a pair of longitudinally extending flanges at oppositeedges of the strip, the flanges diverging toward the opposite conductor plate, the outer edge portions of the flanges engaging the other conductor plate. Downward movement of the topwall and top conductor plate bends one or more of the flanges, so that the flanges engage both conductor plates to close an electrical circuit. I

, 6 Claims, 4 Drawing Figures MAT swrrcu BACKGROUND OF'TI-IE INVENTION controlling door operating mechanisms.

j Many attempts have been made heretofore to provide a pressure operated strip or mat switch which will withstand heavy 'usage,'extremes in temperature conditions and entry of moisture and other foreign material with varying degree of success; Some have been costly to produce and others haveexperienced early failure due to one or more of the above-mentioned causes.

SUMMARY or THE INVENTION 1 An important object of this invention is the provision of a switch which is relatively'simple and inexpensive to produce and which is highly efficient in operation.

Another object of this invention is the provision of a switch which isrugged in construction, long-wearing in use, and imperviousjto varying. weather and environmental conditions. I

To the above endsfl provide a mat switch which comprises a casing of rubber-like insulating material and having a bottom wall, a flexible top wall upwardly spaced'from thebottom wall, and a peripheral wall joining the top and bottom walls at their marginal edges. A pair of vertically spaced upper and lower conallel relationship between the conductor plates laterally inwardly of the peripheral wall of the casing. Each connector strip hasfan elongated transversely intermediate portion that ismounted on one of the conductor plates by a band of electrical insulating material disposed between the intermediate portion and the one conductor plate; the condu'ctor'strip being formed at the opposite edges of the intermediate portion to provide longitudi-- nally extending flanges that diverge toward the opposite conductor plate. Each of the flanges has an outer FIG. 2 is an enlarged fragmentary section taken on the line2-2 of FIG. 1;

FIG. 3 is a view corresponding to FIG. 2 but showing a switch closed position of some of theparts; and 1 FIG. 4 is a still further enlarged fragmentary section corresponding generally to a portion of FIG. 2, showing electrical conductors connected to the conductor plates of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the embodiment of the invention illustrated, a mat, indicated generally at 1, is shown as comprising a bottom wall 2, a top wall 3, and a peripheral wall 4 joining the bottom and

top walls

2 and 3 at their marginal edgesand disposing the top wall 3 in overlyingspaced generally parallel relationship to the bottom wall 2. Although the mat 1 may be of any desired outline, it may be assumed that the same is generally rectangular for the purpose of the present example. Preferably, the mat l is made from flexible electrical insulating material, such "as rubber or synthetic plastic material having electrical insulating qualities, the top, bottom and peripheral walls being bonded-together provide a unitary wall structure'and to seal the interior of the mat against entry of foreign vmaterial. Upper and lower conductor plates Sand 6 respectively are disposed in face-to-face engagement with the inner surfaces of the top wall3 and bottom wall 2 respectively and are maintained in spaced apart relationship at their marginal edge portions bya'marginal spacer strip 7 of suitable electrical insulating material. Preferably, the

conductor plates

5 and 6 are of relatively thin flexible'sheet metal such as copper, bronze or other metal having good electrical conductivity. As shown fragmentarily in FIG. 4, conductor wires 8 and 9 are suitably secured to the

conductor plates

5 and 6 respectively, and may be assumed to extend outwardly of the mat 1 to other portions of a control circuit for whatever mechanism is to be controlled by the switch of this invention. It will be appreciated that the conductors 8 and 9 are covered with 7 suitable insulation outwardly'of their connection to their. respective conductor plates,,and that a sealed edge portion that engages the opposite conductor plate ,to yieldingly hold. the conductor plates in spaced apart relationship. The outer edge. portion of each flange. is preferably of double strip material'thickness, being formed by folding the outer edge portions of the strip backwardly "uponthemselves. When downward movenient is imparted to the top casing wall, at least one of the flanges is bent sothat it engages both the upper and lower conductor plates and closes a circuit through the plates;

DESCRIPTION OF THE DRAWINGS FIG. 1 is a'fragmentary view in perspective of a mat switch produced,in accordance with this invention, away and some parts being some parts, being broken shown in section.

connection, not shown, therebetween and the mat wall structure is effected in theusual manner so as to seal the interior of the mat 1 against entry of foreign matter into the mat at the points where the conductors 8 and between the

conductor plates

5 and 6 when predetermined downward movement is imparted to the top wall 3, I provide a plurality of elongated switch members indicated generally at' 10 disposed in laterally spaced parallel relationship laterally inwardly of the marginal spacer strip 7. The switch members 10 are substantially identical in structure, eachthereof including an' elongated strip of flexible resilient electrical conductor material such as bronze or other metal having similar characteristics, each strip being indicated generally at 11.

The outer longitudinal edges of the flanges 13 are bent or folded backwardly into overlying engagement with the flanges 13, as indicated at 14, to provide longitudinal edge portions 15 that engage the top surface of the lower conductor plate 6. Each of the connector strips ll is secured to the under surface of the conductor plate by means of a respective one of aplurality of bands 16 of insulating material that are suitably bondedor adhered to the upper conductor plate 5 and 'to the intermediate portion 12 of each connector strip When downward movement'is imparted to the upper conductor plate 5, such as would be caused by a person stepping upon an overlying portion of the top mat wall 3, an underlying portion of one or more of the flanges 13 will bend or flex to the extent that the back-folded portion 14 of the flange 13 will make contact with the upper conductor plate 5, while the edge portion 15 continues to engage the lower conductor plate 6, whereby to establish an electrical connection between the

conductor'plates

5 and 6, as shown in FIG. 3. Then, as soon as weight of a person or other given object is removed from the top wall 3 of the mat l, the resilience of the flexed flange 13 will cause the same to assume its normal shape shown in FIGS. 2 and 4 to break the connection between the

conductor plates

5 and 6.

Should downward pressure be applied to an' area intermediate a pair of switch members 10, the upper conductor plate-5 will flex sufficiently to make contact directly with the lower conductor plate 6. At the same time, depending upon the area over which downward pressure is applied, one or more of the adjacent flanges 13 will also flex to a point wherein the circuit is closed between the

plates

5 and 6 either directly or by means of a switch member. 10 or both. The resilience of the plate 5, as well as that of the adjacent switch member or members 10, will cause the upper plate 5 to move upwardly out of engagement with the lower conductor plate 6 as soon as downward pressure against the upper conductor plate is removed.

While I have shown and described a mat having a plurality of connector strips 11 therein, it will be understood that mats can be made having various shapes and dimensions and that this invention contemplates a mat of-suchwidth as to require but a single switch member 10. Such a switch construction is particularly adapted for operation by vehicles running thereover, to control various types of electrical circuits such as for counting devices, parking token dispensing apparatus, and others.

By providing switch members having the construction disclosed, the mat switch of this invention may be subject to loads highly in excess of normal loads without causing the material of the switch members to be bent beyond its elastic limit, whereby the active life of the mat switch of this invenion is substantially greater in overlying spaced generally parallel relationship to said bottom wall, and a peripheral wall joining said top and bottom walls at their marginal edges, said top and bottom walls having opposed inner surfaces in spaced apart relationship;

b. vertically spaced upper and lower conductor plates disposed in face-to-face engagement with the opposed inner surfaces of said top and bottom walls respectively;

c. and spacer means between said conductor plates inwardly spaced from said peripheral wall and including:

1. an elongated connector strip of flexible resilient electrical conductor material formed to provide a generally flat transversely intermediate portion and a pair of longitudinal flanges disposed at oblique angles to said intermediate portion,

2. a band of electrical insulating material interposed between said intermediate strip portion and one of said conductor plates and adhered to said strip portion and said one of the conductor plates to insulate said strip portion from said one of the conductor plates,

3. said flanges diverging toward the other of said conductor plates and having outer longitudinal edge portions in engagement with said other conductor plate to yieldingly hold said conductor plates in spaced apart relationship,

4. said strip being bent responsive to predetermined downward movement applied to said top wall and upper conductor plate to move at least one of said flanges into electrical conducting engagement with both of said conductor plates.

2. The mat switch defined in claim 1 in which said flanges have portions folded backwardly upon themselves on longitudinal lines to provide said outer edge portions with a double material thickness.

3. The mat switch defined in claim 1 in which said band of insulating material is secured to said upper conductor plate, said flanges diverging downwardly from said band, said outer longitudinal edge portions of the flanges engaging said lower conductor plate.

4. Themat switch defined in claim 3 in which said band of insulating material has a thickness at least equal to that of the material of said strip, said flanges having portions folded backwardly into overlying engagement with their respective flanges to provide said outer longitudinal edge portions with a double thickness.

5. The mat switch defined in claim 1 in which said spacer means includes a plurality of said elongated strips of flexible resilient electrical conductor material disposed in laterally spaced parallel relationship, and a plurality of said bands of electrical insulating material one for each of said strips, said bands being secured to said upper conductor plate, the flanges of each strip diverging downwardly toward said lower conductor plate.

6. The mat switch defined in claim 5 in which each of said bands of insulating material has a thickness at least equal to that of the material of its respective strip, said flanges having portions folded backwardly into overlying engagement with their respective flanges to provide said outer longitudinal edge portions with a double thickness.

Claims

1. A mat switch comprising: a. a casing of electrical insulating material and including a bottom wall, a flexible top wall disposed in overlying spaced generally parallel relationship to said bottom wall, and a peripheral wall joining said top and bottom walls at their marginal edges, said top and bottom walls having opposed inner surfaces in spaced apart relationship; b. vertically spaced upper and lower conductor plates disposed in face-to-face engagement with the opposed inner surfaces of said top and bottom walls respectively; c. and spacer means between said conductor plates inwardly spaced from said peripheral wall and including: 1. an elongated connector strip of flexible resilient electrical conductor material formed to provide a generally flat transversely intermediate portion and a pair of longitudinal flanges disposed at oblique angles to said intermediate portion, 2. a band of electrical insulating material interpOsed between said intermediate strip portion and one of said conductor plates and adhered to said strip portion and said one of the conductor plates to insulate said strip portion from said one of the conductor plates, 3. said flanges diverging toward the other of said conductor plates and having outer longitudinal edge portions in engagement with said other conductor plate to yieldingly hold said conductor plates in spaced apart relationship, 4. said strip being bent responsive to predetermined downward movement applied to said top wall and upper conductor plate to move at least one of said flanges into electrical conducting engagement with both of said conductor plates.

4. The mat switch defined in claim 3 in which said band of insulating material has a thickness at least equal to that of the material of said strip, said flanges having portions folded backwardly into overlying engagement with their respective flanges to provide said outer longitudinal edge portions with a double thickness.