Switch element

A switch element ( 1 ) is proposed for valve shut-off, fabricated as cam follower for a plunger rod valve drive of an internal combustion engine, having an outer part ( 2 ) and an inner element ( 4 ) axially movable in its bore ( 3 ) and with rotational security ( 15 ) relative to the guided inner element ( 4 ). The outer part ( 2 ), inside the bore ( 3 ), has an annular groove ( 6 ), and the inner element ( 4 ) has a radial bore ( 7 ) with two diametrically opposed pistons ( 8 ), which to couple the elements ( 2, 4 ) in their axially remote relative position achieved by a lost-motion spring ( 5 ) are displaceable towards the annular groove ( 6 ). On their cam-side under side, emanating from their radially outward, bulbous face, the pistons ( 8 ) segmentwise comprise a plane transverse surface as contact area for a facing under side ( 27 ) of the annular groove ( 6 ). The latter is intersected by two diametrically opposed oil ports ( 11 ) running offset 90° from the pistons ( 8 ) in circumferential direction. In addition, the outer part ( 2 ) has means ( 13 ) for rotationally secured guidance of the switch element ( 1 ) relative to a surrounding structure.