Telescoping lift ram

Claim 1

IN AN INDUSTRIAL TRUCK OF THE CLASS DESCRIBED, A LIFT RAM HAVING A CYLINDER, A RELTIVELY LARGE RAM PISTON AND A RELTIVELY SMALL RAM PISTON IN TELESCOPING RELATION IN THE RAM CYLINDER AND ADAPTED FOR UPWARD LIFTING MOVEMENT RELATIVE TO THE CYLINDER, AND RELATIVELY LARGE RAM PISTON HAVING A LOWER END PORTION FORMED WITH AN OPENING THROUGH WHICH THE SMALL RAM PISTON WILL BE EXPOSED TO FLUID PRESSURE THAT MAY BE APPLIED BELOW THE LARGE PISTON, MEANS FOR DIRECTING FLUID PRESSURE TO THE PISTONS IN THE CYLINDER FOR EXTENDING SAID PISTONS, SAID RAM CYLINDER AND SAID LARGE RAM PISTON BEING CONSTRUCTED TO FORM A CIRCULAR SPACE BETWEEN THAT PISTON AND CYLINDER WITH AN UPPER SURFACE ON THE LOWER END PORTION OF THE LARGE PISTON ACTING AGAINST THE FLUID IN SAID CIRCULR SPACE, FLUID PASSAGE MEANS COMMUNICATING WITH AN UPPER PART OF SAID CIRCULAR SPACE IN THE CYLINDER, A CHECK VALVE CONTROLLING SAID PASSAGE MEANS AND ALLOWING FLUID TO MOVE TO THE CIRCULAR SPACE WHILE NORMALLY IN POSITION RETAINING THE FLUID IN SAID SPACE WHEREBY TO HOLD THE LARGE RAM PISTON IN LOWERED POSITION, MEANS THROUGH WHICH THE SMALL RAM PISTON WHEN LIFTING PLACES SAID CHECK VALVE IN POSITION ALLOWING A DISCHARGE OF FLUID FROM THE CIRCULAR SPACE IN THE CYLINDER SO THAT THE LARGE RAM PISTON WILL LIFT DUE TO THE LIFTING PRESSURE ACTING AGAINST ITS END PORTION, A FURTHER CHECK VALVE CONTROLLING THE OPENING IN THE LOWER END PORTION OF THE LARGE RAM PISTON AND EFFECTIVE FOR RETAINING FLUID PRESSURE RELATIVE TO THE SMALL PISTON WHEN THE LARGE PISTON IS RELIEVED TO LIFTING PRESSURE, AND AN INNER SURFACE OF THE RAM CYLINDER ACTUATING SAID FURTHER CHECK VALVE TO RELEASE THE FLUID PRESSURE RELATIVELY TO THE SMALL RAM PISTON WHEN THE LARGE PISTON MOVES TO LOWERED POSITION.