a bounce - and weld - resistant contact assembly includes a pair of spaced contact plates with facing contacts on their ends . a switch blade is rapidly movable into and out of engagement with the contacts . the contacts are convexities coined into the plates which add no mass to the plates . thus , the natural frequency of the plates is maximized and the magnitude of oscillation of the plates , when the contacts are rapidly engaged by the blade , is minimized . legs on leaf springs act against concavities formed in the plates opposite the convexities . the legs conformally nestle in the convexities so that their frictional engagement therewith and the spring force co - act to quickly damp the high frequency , low magnitude oscillations of the plates . the low mass coined contacts also permit close spacing of the plates to maximize magnetic forces thereon due to current flow therethrough . these forces aid the spring and the leg - concavity friction in quickly damping oscillations of the plates .