Patent ID: 8828048

Claim:
A medical instrument comprising: an elongated element with an end effector positioned at one end of the elongated element, and a hydraulic actuating mechanism for operating the end effector, said hydraulic actuating mechanism including a cylinder with at least one overflow passage for a hydraulic fluid which is connected to an interior of the cylinder by at least one bore, and a piston movable within the cylinder along a longitudinal axis of the cylinder, said piston partitioning the interior of the cylinder into a first cylinder space and a second cylinder space, and connected via a piston rod to the end effector, and including at least one fitting for feeding hydraulic fluid into the first cylinder space and at least one further fitting which is connected to at least one overflow passage of the cylinder, and wherein the at least one overflow passage is formed as a groove on the exterior wall of the cylinder and is connected via the at least one bore to the interior of the cylinder, the cylinder being insertable into a sleeve.