Multi-position fluid motor mechanism

Claim 1

A FLUID MOTOR DEVICE COMPRISING A CYLINDER HAVING A BORE, A FIXED PISTON STOP MEANS CARRIED BY SAID CYLINDER INTERMEDIATE THE ENDS THEREOF AND PROJECTING INTO THE BORE OF SAID CYLINDER, A PAIR OF COAXIALLY ALIGNED CYLINDRICAL HOLLOW PISTONS, EACH OPEN AT BOTH ENDS, RESPECTIVELY SLIDABLY OPERABLE IN SAID BORE ON OPPOSITE SIDES OF SAID STOP MEANS AND EACH HAVING AT ITS OUTER END A FLANGE EXTENDING RADIALLY INWARD, A CYLINDRICAL POWER PISTON MEMBER SLIDABLE OPERABLE AT ITS OPPOSITE ENDS WITHIN SAID HOLLOW PISTONS RESPECTIVELY BETWEEN SAID FLANGES, A PISTON ROD SECURED TO ONE END OF SAID CYLINDRICAL POWER PISTON MEMBER AND EXTENDING THEREFROM, AND A PAIR OF REMOVABLE PRESSURE HEADS CLOSING OPPOSITE ENDS RESPECTIVELY OF THE BORE IN SAID CYLINDER AND PROVIDING ACCESS TO THE BORE WHEN REMOVED FROM SAID CYLINDER, SAID PRESSURE HEADS COOPERATING RESPECTIVELY WITH A CORRESPONDING ONE OF SAID HOLLOW PISTONS AND A CORRESPONDING END OF SAID CYLINDRICAL POWER PISTON MEMBER AND SAID CYLINDER TO FORM A PAIR OF CHAMBER ONE ON EACH SIDE OF SAID CYLINDRICAL POWER PISTON, SAID HOLLOW PISTONS BEING SHIFTABLE BY THE FORCE THEREON OF FLUID UNDER PRESSURE SUPPLIED SIMULTANEOUSLY TO THE CORRESPONDING CHAMBER ON ONE AND ON THE OTHER SIDE OF SAID CYLINDRICAL POWER PISTON MEMBER TO ONE POSITION DETERMINED YB CONTACT OF THE ADJACENT ENDS OF SAID HOLLOW PISTONS WITH THE SAID FIXED PISTON STOPP MEANS, TO CAUSE THE CORRESPONDING INWARDLY EXTENDING FLANGES ON SAID HOLLOW PISTONS TO CORRESPONDINGLY SHIFT THE CYLINDRICAL POWER PISTON MEMBER TO AN INTERMEDIATE POSITION IN SAID CYLINDER, AND EACH ONE OF SAID HOLLOW PISTONS BEING SHIFTABLE OUT OF ITS SAID ONE POSITION BY SAID CYLINDRICAL POWER PISTON MEMBER WHEN FLUID UNDER PRESSURE IS VENTED FROM THE CORRESPONDING CHAMBER ON THE ONE OR ON THE OTHER SIDE OF SAID CYLINDRICAL POWER PISTON MEMBER TO A DIFFERENT POSITION IN WHICH THE RESPECTIVE HOLLOW PISTON IS IN CONTACT WITH THE CORRESPONDING PRESSURE HEAD AND WHICH DETERMINES THE LIMIT OF MOVEMENT OF THE CYLINDRICAL POWER PISTON MEMBER IN A CORRESPONDING DIRECTION OUT OF ITS INTERMEDIATE POSITION.