Apparatus for automatic lubricant delivery

Apparatus for automatic lubricant delivery to a unit to be lubricated, comprising a piston arranged in a cylinder for movement in a direction to force lubricant from the cylinder, an electric-motor drive means connected thereto, and an on switch providing sealing protection, the on switch is arranged in an opening of a housing of the apparatus and upon activation the on switch does not project beyond an outside periphery of the lubricant delivery apparatus, wherein the on switch is of a cylindrical configuration and has two peripherally extending projections whose spacing relative to each other approximately corresponds to a wall thickness of the housing through which the on switch extends and that the second of the projections can be passed through the opening in which the on switch is fitted.