Dome Switch Actuating Apparatus

This invention relates to dome switch actuating apparatus and, in particular, to the mounting and operation of dome switch push buttons operative to make and break an electrical circuit. Pushbuttons of the type with which the invention is concerned have wide usage in microphone devices in radios and the like.

Pushbuttons for actuating dome switches are normally assembled in a housing overlying a circuit board supporting the dome switches. A frame member called an "egg crate" positions the pushbuttons and orients them into operative relation to the switches as described, for example, in U.S. Pat. No. 3,879,586 or U.S. Pat. No. 3,917,917. It has been found that the use of such a frame member is not altogether satisfactory from the standpoint of assembly and ease of operation of the switches. A pushbutton construction not having an "egg crate" frame member is described in U.S. Pat. No. 3,928,741. However, this construction requires special washer construction and actuation from a positive linear force and thus restricts it application.

In accordance with the instant invention, pushbuttons are assembled in overlying relation to dome shaped switches positioned on circuit board without the use of the "egg crate". Furthermore, it is possible to align and captivate the actuating button in such a manner as to afford greater tolerances in the actuation of the dome switch. More specifically, a pivoting or rocking action in the sense of a "joystick" can be imparted to the pushbutton as well as the normal up and down or linear motion to open and close the dome switch.

It is therefore a general object of the present invention to improve pushbutton actuating devices for dome shaped switches.

It is a further object of the present invention to improve the alignment and captivation of actuating pushbuttons for dome shaped switches.

It is still a further object of the present invention to simplify the assembling and construction of pushbuttons by eliminating the need of an "egg crate" frame.

It is still a further object of the present invention to enable greater tolerances for operation of pushbuttons so that joystick operation is possible to actuate dome switches.

It is still a further object of the present invention to provide a simplified construction for pushbuttons operating dome switches.

These objects as well as others will become more apparent after an understanding of the following description which we should be considered in conjunction with the accompanying drawings in which:

FIG. 1 is an isometric view of a microphone employing the pushbutton actuating apparatus according to the present invention.

FIG. 2 is a side sectional view of a pushbutton apparatus of the invention, and

FIG. 3 is an exploded isometric view of the pushbutton apparatus illustrating certain details thereof.

In FIG. 1 there is shown a microphone assembly generally designated 10 having a plurality of pushbutton members 15 which are used to momentarily contact and thus close circuits associated with the microphone assembly operation. Typically a key member 17 is actuated to transmit voice signals through the microphone assembly.

As shown in FIGS. 2 and 3, each of the pushbutton members 15 is mounted on a circuit board member 20 in overlying relation to a dome switch 25. Switch 25 is actuated by momentary force with pushbutton member 15 in a manner to be described more fully hereinafter. It will be noted that pushbutton member 15 has an elongated body 30, a tip portion 32 and a plurality of vertically extending leg members 34. At the ends of leg members 34 are hook portions 36. It will be noted that tip portion 32 and leg members 34 are offset by a distance and Y, respectively (FIG. 2) from the longitudinal axis of the pushbutton body 30. By this structure stability in mounting and actuation is accomplished as will become more apparent hereinafter.

Circuit board 20 has openings 50 formed therein through which leg members 34 are received with hook portions 36. By this structure pushbutton members 15 are maintained in alignment and captivate over dome switch 25, through the cooperating action of leg members 34 and hook portions 36 and circuit board member 20.

In accordance with the invention positioned intermediate the pushbutton members and the dome switch 25 is an elastomeric member 40 which has an aperture 42 formed therein through which the tip portion 32 extends for a predetermined distance. It will be appreciated that by applying a downward force to the pushbutton member 15 that contact is made between tip portion 32 and switch member 25 against the biasing action afforded by elastomeric member 40. Upon release of the force on the pushbutton member contact between top portion 32 and switch member 25 is opened thereby breaking the circuit operation. By virtue of the offset X and Y of tip portion 32 and leg members 34 from the longitudinal axis of body 30, it is possible to actuate the dome switch 25 by a pivoting or rocking force. This is advantageous from the standpoint greatly facilitating operation of the dome switch and associated microphone circuit.

It will be appreciated that pushbutton member 15 can be made of either conductive or non-conductive material depending on circuit application. Thus where only physical contact is required, a conductive material is used. On the other hand where pressure or insulating circuits or materials are necessary, a non-conductive material is used.

By the above described invention the pushbutton member can operate the dome switch through a pivoting or rocking action as well as a downward or linear force. Thus, the operator has freedom to operate switch by rocking in joystick fashion. Moreover, much greater tolerances are provided for actuation of the switches and the "egg crate" frame is eliminated.

Although the invention has been shown in a specific embodiment, it is obvious that other variations and modifications are possible and it is intended to include all such as fall within the spirit and scope of the appended claims.