TELEPHONE KEYPAD UNIT COMPOSED OF DOUBLE-SWITCHED BUTTONS

摘要

PURPOSE: A telephone keypad unit composed of double-switched buttons is provided to install two switches for each button so that each switch contact can individually be operated according to a push location of each button. CONSTITUTION: Twelve buttons(221) are formed on a compressed and molded silicon rubber plate(220). An outer wall(222) of each button(221) is so elastic that the wall gets pleated and compressed when a user pushes a button. The silicon rubber plate(220) prevents other materials from intruding into a lower substrate. Numerals and characters are printed on the key caps of the buttons(221). Two bosses(25a,25b) are formed on the lower part of each button. If the user pushes a button, these bosses(25a,25b) contacts a membrane tactile(231) and transfers pressure so that the membrane tactile(231) can be deformed.