US3794790A - Electrical switches - Google Patents

Abstract

An electrical switch including a first flexible elongated conductor and a second flexible elongated conductor coaxial with the first conductor. An insulating element which is both resilient and deformable spaces the first conductor from the second conductor along the whole length of the first conductor, and the insulating element is loaded with conductive particles. The nature of the insulating element containing the conductive particles is such that compression of the element in a direction to decrease the spacing between the first and second conductors establishes a conductive path within the element between the first and second conductors.

Description

United States Patent [191 Leyland Feb. 26, 1974 ELECTRICAL SWITCHES [75] Inventor: Kenneth Leyland,

' Newcastle-under-Lyme, England [73] Assignee: Rists, Wires and Cables Limited, Newcastle-under-Lyme, England [22] Filed: Jan. 24, 1973 [2]] Appl. No.: 326,339

[30] Foreign Application Priority Data Apr. 2, 1972 Great Britain 5,276/72 [52] US. Cl. 200/86 R, 200/86 A, 338/114 [51] Int. Cl. H0lh 13/16 [58] Field of Search 338/99, 100, 114; 200/86 R,

. ZOO/61.43

[56] References Cited UNITED STATES PATENTS 2,305,717 12/1942 La Bell 338/114 2,445,660

7/1948 Bruestle 338/114 1/1973 Richards ZOO/61.43

3,710,050 3,509,296 4/1970 Harshman et a1 280/86 3,321,592 5/1967 Miller 200/86 R Primary ExaminerDavid Smith, Jr. Attorney, Agent, or Firm-l-lolman & Stern [5 7] ABSTRACT An electrical switch including a first flexible elongated conductor and a second flexible elongated conductor coaxial with the first conductor. An insulating element which is both resilient and deformable spaces the first conductor from the second conductor along the whole length of the first conductor, and the insulating element is loaded with conductive particles. The nature of the insulating element containing the conductive particles is such that compression of the element in a direction to decrease the spacing between the first and second conductors establishes a conductive path within the element between the first and second conductors.

2 Claims, 1 Drawing Figure ELECTRICAL SWITCHES This invention relates to electrical switches.

A switch according to the invention includes a first flexible elongated conductor, a second flexible elongated conductor, and a resilient, deformable insulating element spacing the first conductor, throughout its length, from the second conductor, the insulating element being loaded with conductive particles whereby compression of the element in a direction to decrease the spacing of the first and second conductors establishes a conductive path within the element between the first and second conductors.

Desirably the first conductor is in the form of a conductive wire or lead, the insulating element is in the form of a sheath within which the first conductor extends, and the second conductor is in the form of a conductive braid encircling said element.

Conveniently the switch also includes an outer flexible protective sleeve.

The accompanying drawing is a diagrammatic representation of an electrical warning system utilizing a switch in accordance with'one example of the invention.

Referring to the drawing the switch 11 includes a first electrical conductor in the form of a copper wire 12. Encircling the wire 12 is an insulating element 13 in the form of a sheath of a resilient deformable insulating material which is loaded with spaced electrically conductive particles, whereby compression of a part of the element 13 urgesthe adjacent particles into contact to render that part of the element 13 conductive. The first conductor 12 extends within the element 13, the element 13 constituting a sheath encircling the conductor 12. Encircling the element 13, is a woven copper braid l4, and in the rest condition of the element 13, the element 13 serves to electrically insulate the copper braid 14 from the copper wire 12. Both the wire 12 and the braid 14 are of course flexible. Deformation of the eletraffic monitoring, or warning systems where a length.

of the switch will be laid across the path of the vehicle. As the vehicle passes over the switch an electrical circuit will be completed momentarily between the braid 14 and the wire 12, and the switch can thus be used to control a device 15 for example a bell or a buzzer in the sheath spacing said first conductor, throughout its length, from said second conductor said sheath encircling said first conductor, the material of said sheath being loaded with conductive particles, whereby compression of said sheath in a direction to decrease thev spacing of said first and second conductors establishes a conductive path within said sheath between said first and second conductors.

2. A switch as claimed in claim 1 wherein the switch also includes an outer flexible protective sleeve.

Claims (2)

1. An electrical switch including a first flexible elongated conductor in the form of a conductive wire, a second flexible elongate conductor in the form of a conductive braid, and a resilient, deformable insulating sheath spacing said first conductor, throughout its length, from said second conductor said sheath encircling said first conductor, the material of said sheath being loaded with conductive particles, whereby compression of said sheath in a direction to decrease the spacing of said first and second conductors establishes a conductive path within said sheath between said first and second conductors.

2. A switch as claimed in claim 1 wherein the switch also includes an outer flexible protective sleeve.

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