A push
button switch is used to either close or open an electrical circuit depending
on the application. Push button switches are used in various applications such
as industrial equipment control
handles, outdoor controls, mobile communication terminals, and medical
equipment, and etc. Push button switches generally include a push button
disposed within a housing. The push button may be depressed to cause movement
of the push button relative to the housing for directly or indirectly changing
the state of an electrical contact to open or close the contact. Also included
in a pushbutton switch may be an actuator, driver, or plunger of some type that
is situated within a switch housing having at least two contacts in
communication with an electrical circuit within which the switch is
incorporated.
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Fig Pushbutton
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Typical
actuators used for contact switches include spring loaded force cap actuators
that reciprocate within a sleeve disposed within the canister. The actuator is
typically coupled to the movement of the cap assembly, such that the actuator
translates in a direction that is parallel with the cap. A push button switch
for a data input unit for a mobile communication device such as a cellular
phone, a key board for a personal computer or the like is generally constructed by
mounting a cover member directly on a circuit board. Printed circuit board
(PCB) mounted pushbutton switches are an inexpensive means of providing an
operator interface on industrial control products. In such push button
switches, a substrate which includes a plurality of movable sections is formed
of a rubber elastomeric.
The key top is formed on a top surface thereof with a figure, a character or
the like by printing, to thereby provide a cover member. Push button switches
incorporating lighted displays have been used in a variety of applications.
Such switches are typically comprised of a pushbutton, an opaque legend plate,
and a back light to illuminate the legend plate.