Hydromechanical automatic reversing device for linear hydraulic rams

A hydromechanical apparatus comprising:

• a hydraulic machine including a ram body and a ram piston movable in opposite linear directions in said ram body;
• a support block mounted on said ram body;
• ram distributor valve means, including a spool movable in opposite linear directions, operatively connected to said hydraulic machine for, upon movement of said spool in opposite linear directions, reversing the direction of movement of said ram piston within said ram body;
• a pendular arm having first and second ends, said first end being pivotally connected to said spool, said second end supporting a pivot shaft journalled in said support block and an extension positioned eccentric to said pivot shaft;
• a rod rigid with and extending parallel to and laterally spaced from said ram piston and movable therewith in opposite linear directions;
• a pair of adjustble rigid stop means carried by said rod for, upon movement of said ram piston in opposite linear directions, engaging said extension, thereby rotating said pendular arm in opposite directions about said pivot shaft and causing movement of said spool in opposite linear directions, thus causing said ram distributor valve means to reverse the direction of movement of said ram piston within said ram body;
• the dimensions of said pendular arm, between said extension and said pivot shaft and between said pivot shaft and said first end of said pendular arm, being selected such that a relatively short stroke of said ram piston transits a highly stepped-up length and speed of stroke to said spool, thus obtaining a high degree of precision at the motion reversing positions of said ram piston and a high speed reversal of said spool of said ram distributor valve means;
• and
• said ram distributor valve means including damping chamber means for, in cooperation with said spool, damping movement of said spool and absorbing shocks and preventing rebounds thereof.