Patent ID: 8826494

Claim:
A door closer having a free-swing function, comprising: a door closer housing; an output shaft configured to be connected to a door that comprises a cam-shaped rolling contour configured as a cam disc; a piston assembly connected to the output shaft and guided in the door closer housing that comprises: at least one cam roller that abuts on the rolling contour; a damper piston including a first cam roller of said at least one cam roller; and an opening piston including a second cam roller of said at least one cam roller, wherein the output shaft is arranged between the damper piston and the opening piston; a closer spring; a piston rod that connects the piston assembly to the closer spring; a free-swing assembly for translational motion of the piston assembly decoupled from the closer spring when the closer spring is locked; and a hydraulic lock compartment configured to lock the closer spring, wherein the damper piston and the opening piston are connected via four tie rods.