lubrication device for a piston

The piston (10) has a piston upper part (1) and a piston lower part (3) connected with each other by a clamping element (4) i.e. clamping screw. A lubricating device (5) lubricates a bearing surface of a cylinder in which the piston moves in front and back directions and is arranged inside the clamping element. The clamping element includes a lubricant reservoir, and the piston upper part is moved relative to the piston lower part, so that the lubricant reservoir is variable in size. Shut-off elements are arranged on ends of the lubricant reservoir.