Constant load extension device

Claim 1

A SUBSTANTIALLY CONSTANT LOAD EXTENSION DEVICE FOR USE BETWEEN TWO RELATIVELY MOVABLE PARTS OF A MACHINE COMPRISING A CYLINDER, A ROD EXTENDING WITHIN SAID CYLINDER AND PROJECTING OUT OF SAID CYLINDER AT ONE END THEREOF, GLAND MEANS AT SAID ONE END OF SAID CYLINDER, SAID GLAND MEANS PERMITTING AXIAL MOVEMENT OF SAID ROD RELATIVELY TO SAID CYLINDER, EACH OF SAID ROD AND SAID CYLINDER BEING ADAPTED FOR ATTACHMENT TO PARTS OF A MACHINE, A FREE PISTON WITHIN SAID CYLINDER AND SURROUNDING SAID ROD, SAID PISTON MAKING SUBSTANTIALLY FLUID-TIGHT SEALING ENGAGEMENT WITH SAID CYLINDER, BUT HAVING FREEDOM FOR AXIAL MOVEMENT WITHIN SAID CYLINDER AND RELATIVE TO SAID ROD, AN ABUTMENT ON SAID ROD, RESILIENT MEANS MOUNTED BETWEEN SAID ABUTMENT AND SAID PISTON SAID RESILIENT MEANS OPPOSING MOVEMENT OF SAID ROD OUT OF SAID CYLINDER, MEANS PROVIDING A FLUID PASSAGE FROM ONE SIDE OF SAID PISTON TO THE OTHER AND VALVE MEANS WITHIN SAID PASSAGE, SAID VALVE MEANS BEING CONTROLLED ON ITS OPENING MOVEMENT BY RELATIVE MOVEMENT BETWEEN SAID ROD AND SAID PISTON, WHEREBY SAID PISTON CAN YIELD TOWARDS SAID ONE END OF SAID CYLINDER WHEN SAID PASSAGE IS OPENED, SAID VALVE MEANS COMPRISING AN ANNULAR RIGID RING, AND A RESILIENT RING ENGAGING ONE FACE OF SAID RIGID RING, A SHOULDER ON SAID PISTON ENGAGING PART OF THE OPPOSITE FACE OF SAID RIGID RING TO THAT ENGAGED BY SAID RESILIENT RING, AND A SHOULDER ON SAID ROD ALSO ENGAGING SAID OPPOSITE FACE OF SAID RIGID RING AND LOADING MEANS WITHIN SAID CYLINDER, SAID LOADING MEANS ENSURING MAINTENANCE OF FLUID PRESSURE ON SAID ONE END OF SAID PISTON ON MOVEMENT OF SAID ROD INWARDLY OF SAID CYLINDER.