Variable-stroke pneumatic cylinder

A pneumatic cylinder, comprising:

• a tubular casing defining a chamber for a piston member;
• a fore and a rear cylinder head at the ends of the piston chamber, at least the rear one of the cylinder heads being provided with an inlet/outlet hole for feeding and discharging pressurized air, said air inlet/outlet hole opening into a central cavity facing a corresponding side end of the piston chamber;
• a reciprocable piston member movable along a working stroke inside the piston chamber, said piston member having a piston rod which tightly protrudes from the fore cylinder head;
• in which at least the rear cylinder head is provided with a pneumatic damping device comprising a venting path;
• and
• in which the piston member comprises a plug member designed to tightly penetrate into the central cavity of said rear cylinder head;
• and
• head extension means for axial extension of the rear cylinder head inside the piston chamber for varying the working stroke of the piston member, said head extension means comprising at least one disk-shaped member removably fastened to the rear cylinder head, inside the piston chamber,
• said disk-shaped member having a central hole axially aligned to the central cavity of the rear cylinder head, and a side hole axially aligned with a venting hole branched off from the air venting path.