Patent ID: 7033149

Claim:
A medium pump, in particular a lubricating oil pump for a motor chain saw, comprising a pump case with a pump cylinder and a pump piston positioned displaceable in the pump cylinder in direction of a pump axle, removable on one side, whereby the pump piston, by rotation about the pump axle by running off an oblique control surface placed on the pump piston on a control head of an adjustable pump lift adjusting device realizes axial pump movements against the pressure of a first spring, whereby the pump lift adjusting device is positioned removable in a guide placed transversely to the pump axle and fixedly connected with the pump case, whereby the pump piston in the pump cylinder is maintained against the pressure of the first spring by the pump lift adjusting device in such a way that, after having removed the pump lift adjusting device out of the guide, the pump piston can be freely removed from the pump case, characterized in that the pump lift adjusting device can be removed out of the guide without any tool, whereby axially running grooves are provided in the guide, grooves in which laterally projecting trunnions are guided when the pump lift adjusting device is drawn out of the guide after a torsion into a predetermined angular position.