The present invention relates to pressure activated linear switches and more specifically to improved pressure activated linear switch apparatuses that can be directly connected to an external surface, have ergonomic structures to facilitate activation and a range of external connector configurations.
Linear switches have a broad range of applications that include mats that activate doors, electrical safety interrupts and automobile sensors. The problems associated with linear switches are well known and include those associated with coiling for transportation and storage as well as the ability to mass produce switches tailored for individual applications.
In particular, the tailoring of linear switches to individual applications can be a time consuming problem in which a section of linear switch is cut, spliced and hard wired into a circuit. This connection between the conductors of the switch and circuit can become an additional reliability problem beyond that of the switch itself. Further, the failure of the switch requires the removal and replacement of a hard wired portion of the circuit that is often further complicated by the use of a specialized channel or adhesive that attaches and fixes the switch to an external surface.
Linear switches are typically fixed in position against a substantially rigid surface in order to assure reliable activation. Specialized channels can fix linear switches in position and facilitate the activation of the switch, but these channels require additional fasteners to be installed and then a cumbersome and time consuming sliding integration of the linear switch and channel.
Another problem with linear switches is their lack of sufficient tactile sensation. Many common linear switches employed in channels, for example, have a raised backbone or ridge along the top longitudinal centerline of the switch that is made of the same dense polymer or rubber materials as the jacket. This raised backbone can facilitate switch actuation in many automated or industrial applications by providing a limited tactile sensation of the switch and direction for activating the switch, but locating and compressing the dense polymer or rubber materials along the narrow ridge can be difficult for many applications.
A linear pressure switch apparatus is needed that has an attachment mechanism for readily fixing into position, connectors for ease of placement and removal from a circuit and that can be actuated with a softer tactile sensation with improved ergonomic qualities. Further, a linear pressure switch apparatus is needed that can discriminate between a range of actuation forces.
A linear pressure switch apparatus is described that comprises a first elongate conductor plate that has a pair of opposed faces, a second elongate conductor plate that has a pair of opposed faces and at least one insulative strip that separates and electrically isolates the first conductor plate and the second conductor plate. A jacket encases the structure of the conductors and the at least one insulative strip. The jacketed structure provides an at least water resistant barrier. An attachment mechanism is adapted to fix the jacketed structure in position on an external structure.
A linear pressure switch apparatus is described that comprises a first elongate conductor plate that has opposed terminal end portions, a second elongate conductor plate that has opposed terminal end portions, an insulative strip that separates and electrically isolates the first conductor plate and the second conductor plate. A jacket encases the conductors and the at least one insulative strip and provides a jacketed structure that is at least water resistant barrier. A set of connectors are coupled to the terminal end portions of the conductors that extend through the jacket and are adapted to interface with a mating set of conductors.
A linear pressure switch apparatus is described that comprises a first elongate conductor plate that has opposed terminal end portions, a second elongate conductor plate that has opposed terminal end portions, an insulative strip that separates and electrically isolates the first conductor plate and the second conductor plate. A jacket encases the conductors and the at least one insulative strip and provides a jacketed structure that is at least water resistant barrier. A bias member is positioned between the jacket and the first elongate conductor plate that is a resilient foam. The bias member provides a tactile sensation to the activating of the conductors.
A linear pressure switch array is described that comprises a first elongate conductor plate that has a pair of opposed faces, a second elongate conductor plate that has a pair of opposed faces, a first insulative strip that separates and electrically isolates the first conductor plate and the second conductor plate, a third elongate conductor plate that has a pair of opposed faces, a fourth elongate conductor plate that has a pair of opposed faces, a second insulative strip that separates and electrically isolates the third conductor plate and the fourth conductor plate, a fifth elongate conductor plate that has a pair of opposed faces, a sixth elongate conductor plate that has a pair of opposed faces and a third insulative strip that separates and electrically isolates the fifth conductor plate and the sixth conductor plate. The sensitivity of each pair of conductive plates varies to provide a range of activation signals. A jacket encloses the conductor plates and insulative strips to form a jacketed structure.
Preferred embodiments of the invention are described below with reference to the drawings, wherein like numerals are used to refer to the same or similar elements.
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Switch 10 is shown as an in-line switch with a first set of connectors 13 and a second set of connectors 15 that are adapted to interface with mating connectors. Connectors 13 and 15 are shown as standard spade connectors, but it is understood that connectors 13 and 15 can have any structure, angular orientation, positioning or configuration. Connectors 13 and 15 advantageously facilitate the field installation and removal of switch 10 in a circuit.
Insulation 16 has a predetermined thickness that provides an air gap that separates and electrically isolates conductors 12 and 14 in a first position of switch 10. Insulation 16 is preferably a pair of strips of insulation 16 with each strip positioned in proximity to one of longitudinal edges 18. Insulation 16 extends approximately the length of switch 10. Insulation 16 can vary in both lateral width, height and in material to provide a desired degree of switch sensitivity. Insulation 16 is preferably a resilient foam material that separates conductors 12 and 14 in the first position and can be compressed by a force approximately perpendicular to face 22 to make electrical contact between conductors 12 and 14 in a second position. In one preferred embodiment, insulation 16 is 3M—No. 4016 double coated urethane foam tape. The approximate height of the air gap provided by insulation 16 can vary depending upon the desired application, but typically ranges between 0.003 and 0.1875 inches.
Linear switch 10 preferably includes an attachment mechanism 26 that fixes switch 10 in position against an external surface. Attachment mechanism 26 as defined herein is a mechanical device for securely fixing switch 10 to an external structure without the use of adhesives. In this preferred embodiment, attachment mechanism 26 is a set of at least one aperture that is adapted to receive one or more fasteners 28 that extend through switch 10 and into the external structure. Fasteners 28 are preferably threaded screws that can be fabricated from any suitable material such as for example metals, polymers and/or composites that securely attach switch 10 to the external structure.
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In addition, one or more additional insulation members 34 are preferably added in proximity to aperture 30 to provide an insulation barrier between conductors 12 and 14. Insulation members 34 are preferably the same material as insulation strips 16. Insulation members 34 are shown as strips approximately perpendicular to the longitudinally aligned insulation strips 16, but it is understood that insulation 34 can have any shape, material or angular orientation to include a planar circular disc or angular shape that provides the required electrical isolation of conductors 12 and 14 when switch 10 is fixed in position by fastener 28.
It is also understood that apertures 30 can be positioned at any location on switch 10, to include through insulation strips 16, depending upon the intended application. Apertures 30 are preferably positioned approximately along the longitudinal centerline of switch 10 to minimize the number of apertures 30 and fasteners 28 to advantageously reduce the time required for installation and removal of a given switch 10. Alternatively, apertures 30 in proximity to longitudinal edges 18 preserve the continuous activation capability of switch 10. Apertures 30 in proximity to longitudinal edges 18 that extend through insulation strips 16 can selectively include a washer, grommet or sleeve to improve the resistance to water intrusion. Fasteners 28 in applications with apertures 30 in proximity to longitudinal edges 18 can also have heads with reduced dimensions in one or more dimensions so that the heads of fasteners do not extend beyond longitudinal edges 18.
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In the preceding specification, the present disclosure has been described with reference to specific exemplary embodiments thereof. It will be evident, however, that various modifications, combinations and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the claims that follow. While the present invention is described in terms of the varying embodiments of attachment mechanisms, connector configurations, soft actuation, and multiple circuit sensitivity for example can be combined with one or more novel features of the other embodiments. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.
This application is a continuation of and claims priority to patent application Ser. No. 11/983,349 filed Nov. 8, 2007 now U.S. Pat. No. 7,659,485.
Number | Name | Date | Kind |
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3811025 | Bach | May 1974 | A |
4922067 | West | May 1990 | A |
20050061649 | Howie et al. | Mar 2005 | A1 |
Number | Date | Country | |
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20100096245 A1 | Apr 2010 | US |
Number | Date | Country | |
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Parent | 11983349 | Nov 2007 | US |
Child | 12642628 | US |