Transmission element, in particular a roller tappet for operating a valve, in particular for an internal combustion engine

The invention concerns a force-transmission element, in particular a roller tappet (1) which actuates a valve in an internal-combustion engine. In order to prevent rotation of the tappet, a securing device is fitted which engages both with the force-transmission element and in a suitably shaped groove in the engine casing. This is done with a simple design solution by using as the securing device a Woodruff key (7), conforming with DIN 6888, which is fitted in a suitably shaped recess (6) in the bottom (3) of the tappet (1).