Electricity: circuit makers and breakers – Special application – Actuated concurrently with operation or use of art device
Reexamination Certificate
1999-11-24
2001-01-09
Gellner, Michael L. (Department: 2832)
Electricity: circuit makers and breakers
Special application
Actuated concurrently with operation or use of art device
C200S061430, C200S061410
Reexamination Certificate
active
06172315
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a contact switch and, more specifically, to a linear contact switch that can be manufactured in continuous lengths and can be activated upon pressure anywhere along its perimeter.
BRIEF DESCRIPTION OF THE PRIOR ART
Linear contact switches (sometimes referred to as edge contact switches) are generally known in the art. The basic elements of a linear contact switch include a pair of elongated conductors centrally located within a cavity of an elongated housing. The housing is comprised of a relatively rigid, flat strip, which forms the bottom of the housing, joined to a flexible, concave-shaped upper section. The bottom strip and the concave upper section define the cavity through which the conductor runs. One elongated conductor is attached to the bottom strip and the other elongate conductor is attached to the upper section of the housing in a spaced apart relationship. A pair of wires soldered to the ends of the conductors are used to connect the linear switch to an external circuit.
Usually, linear contact switches are “normally open” (i.e., in their rest positions the switch does not conduct). The upper section of the housing depresses in response to an external force, thereby moving the upper section along with its associated conductor into contact with the bottom conductor which activates or “closes” the switch.
A drawback of such linear switches is that the external force must be applied at the apex of the concave upper section, and in a substantially perpendicular direction, in order to ensure that the conductors make physical contact, thereby closing the switch. Accordingly, prior art linear switches have “dead” spots along their perimeters or circumferences which would not activate the switch no matter how much external force is applied at that spot. Since a common use for linear switches is on the leading edge of a movable door as part of a safety circuit, the failure of a switch to activate may result in a fatal accident.
Another drawback of prior art linear switches is that they are position sensitive. That is, the linear switch must be precisely located with its bottom strip secured to an object and the concave-shaped upper section projecting outward from the object.
SUMMARY OF THE INVENTION
The present invention is a linear switch that can be activated upon the application of force anywhere along its external perimeter (i.e., along the entire length of the switch as well as any point on the radial circumference of the switch). In other words, the design of the subject invention eliminates “dead” spots.
The subject invention has a non-conductive (i.e., an electrically insulative) housing. Two separate interior channels, separated by an actuator, run the length of the housing. Within each channel, a pair of electrically conductive, flexible strips are secured. One conductive strip from each pair is secured on either side of the actuator with glue, double sided tape or adhesive scrim cloth. The other contact strip from each pair is secured, in diametrically opposite position across their respective channels, to the interior surface of the housing. A perforated foam separator for each pair of conductive strips keeps them in spaced-apart relationship when there is no external force.
A lead wire is soldered onto the first ends of each conductive strip for connecting the switch to a remotely located electrical circuit(s).
Since there are two pairs of conductive strips, one pair in each channel, there are effectively two separate switches. However, in a preferred embodiment, the first conductive strip of the first pair of conductive strips is connected to the first conductive strip of the second pair of conductive strips, and the second conductive strip of the first pair is connected to the second conductive strip of the second pair of conductive strips; the connections are preferably made at the second end of each conductive strip by a wire or jumper. In this preferred embodiment, pressure at any point along the length of the switch—and at any point around the circumference—will activate the actuator thereby closing the subject linear switch (i.e., it has 360 degree sensitivity).
In another aspect, the actuator of the present invention is modified by separating it into two different sections. The subject linear contact switch comprises first and second resilient strips, each having first and second longitudinal edges, an outer surface and an inner surface. First and second complementary strips also having first and second longitudinal edges are joined to the respective first and second longitudinal edges of the first and second resilient strips, respectively, forming two tubular members.
The inner cavity of each tubular member forming first and second channels. The tubular members are then joined together at first and second seams along the entire longitudinal length thereof such that the first and second resilient strips form the outer surface of a housing and the first and second complementary strips form the actuator.
Beads are located along the seams between the resilient strips and the respective complementary strips, and/or between the complementary strips so that the first and second resilient strip remains arched outwards, and the first and second complementary strips are arched slightly outwards in a radially direction to form a third interchannel between the two complementary strips.
As with the previous embodiment, electrically conductive strips are located in the first and second channels. If desired, two oppositely facing conductive strips may also be located in the third channel. The advantage of this embodiment is that the complementary strips, acting as two independent actuators, tend to move in opposite directions upon the application of an external force. This allows two separate surfaces to be connected to the linear switch or, if the conductive strips are jumpered together, to have a backup or fail-safe switch. Further, if the conductive strips are placed in the third channel, a third switch, normally closed, may be needed to respond to changing requirements.
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Miller Bearge
Miller Norman K.
Garzia Mark A.
Gellner Michael L.
Miller Edge, Inc.
Nguyen Nhung
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