Dashpot for damping a closing movement of a closure system

A dashpot for damping a closing movement of a closure system having a support and a closure member that are hingedly connected to each other, the dashpot comprising:

• a metal cylinder barrel having a longitudinal direction;
• a closed cylinder cavity formed within the cylinder barrel and being filled with a volume of hydraulic fluid;
• a damper shaft which extends into the cylinder cavity, the cylinder barrel and the damper shaft being rotatable with respect to one another about a rotation axis which is substantially parallel to the longitudinal direction;
• a piston within said cylinder cavity which is operatively coupled to said damper shaft to be movable between two extreme positions in said longitudinal direction upon a relative rotation between said cylinder barrel and said damper shaft;
• and
• a motion converting mechanism to convert the relative rotation between said cylinder barrel and said damper shaft into a sliding motion of the piston, the motion converting mechanism comprising:
• a plastic tubular element that is fixed to said cylinder barrel;
• and
• two screw threads which are arranged to cooperate with one another so that upon a relative rotation between said cylinder barrel and said damper shaft in a first rotational direction the piston moves along the damper shaft in a first direction whilst upon a relative rotation between said cylinder barrel and said damper shaft in a second rotational direction, which is opposite to the first rotational direction, the piston moves along the damper shaft in a second direction, which is opposite to the first direction, the first and second directions being substantially parallel to the longitudinal direction,
• characterized in that a first one of said two screw threads is provided on an outer wall of the piston and a second one of said two screw threads is provided on an inner wall of the plastic tubular element, with the piston being slideable along said longitudinal direction on said damper shaft and with a rotation prevention system being provided between the piston and said damper shaft for preventing rotation of the piston with respect to the damper shaft.