CONED DISK SPRING

摘要

This invention relates to a coned disk spring which is used as a diaphragm and a keytop returning spring of a keyboard switch, or the like. The coned disk spring (D) of the present invention has a structure whose corrugated section describes spiral ripples (P) around the center circle (10) of a blank sheet starting at its arbitary circumferential points. The spiral ripples (P) can start at at least two points of equidistant points on the circumference of the center circle and preferably, at odd-numbered equidistant points. The coned disk spring (D) of this invention does not exhibit eccentric stress and operating direction at the time of deflection but undergoes a uniform deflection in a circumferential direction, when it is used as a diaphragm. When it is used as a spring for returning the keytop (43) of a keyboard switch, the pressing force of the keytop (43) is transmitted to the entire region and the spring can undergo smooth deflection and can exhibit a reliable switch operation. It is advisable to support and fix the dish spring (D) of the present invention by applying a tension in a centrifugal direction to the entire circumference of its outer periphery. In this manner, deflection of the entire region of the dish spring can be made uniform.