Flexural Vibrations of a Propped Cantilever

Iii relays and other switching apparatus, contact chatter and certain types of wear are associated with vibrations of the contact springs. As an aid in the study of these vibrations, the general theory of beam vibration has been used to develop an analytical treatment applicable to the important class of contact springs which can be considered as propped cantilever beams of uniform cross-section. In almost all common types of switching apparatus, the contact springs are cantilever beams, clamped at the terminal end, which carry the contact at the free end. When the contact is open, the spring is usually propped or supported by a card or stud, and is therefore a propped cantilever. In some devices, the spring is supported at both the stud and contact when the latter is closed, and is then a doubly propped cantilever. In others, the spring is supported only at the contact when the latter is closed, and is therefore a singly propped cantilever in both operate and release, although the prop location differs for the two cases. Sometimes the mating contact is mounted on another spring, which constitutes a flexible prop, as contrasted with the (relatively) fixed and rigid prop provided by a card or stud. The relations given here apply only to a uniform cantilever with a f>09