Patent ID: 8350649

Claim:
A plunger switch for use as a switch element in an electrical circuit, comprising a housing and a plunger that is able to move axially in a bore of the housing in a direction of a longitudinal axis and when in an operating position in which it is depressed toward the housing, acts on an electronic sensor unit situated in the housing, which in turn initiates a switching procedure in the electrical circuit by electrical pulses, wherein the plunger, in its axial plunging region into a bore of the housing, is peripherally provided with at least two lubricating grooves, wherein the lubricating grooves permit a lubricating fluid to travel into the axial plunging region between the plunger and bore, wherein the electronic sensor unit has means for protecting the electronic sensor unit from a penetration of lubricating fluid, and wherein the at least two lubrication grooves extend around the longitudinal axis of the plunger in form of a double helix.