Hydraulic jack with mechanical safety block.

摘要

To block the piston (4) in any position of its travel, the piston and relative stem (4 min ) has a cavity which extends axially from the surface of the piston head for a length approximately equal to the travel of the piston. Within the said cavity there is a spherical turning screw (6) fixed to the centre of the bottom wall of the said cavity. The said screw is engaged in a reversible manner with its collar (8) which is fixed to the extremity of a hollow shaft (10) which protrudes beyond the cylinder head wall (12) of the jack. To the projecting terminal piece (24) is fixed a free wheel (26) of which one part is keyed into the said terminal piece and the other part is a ring with a toothed profile. A blocking catch with an anti-engagement system may be engaged by hydraulic or manual command in the teeth of the said toothed profile.