Patent ID: 6017170
Filing Date: 2000-01-25
Classification: E02D

Abstract:
A shoring strut comprising:a cylinder;a drive piston and a working piston recprocatingly mounted in said cylinder;a first chamber in said cylinder for receiving a first fluid, said first chamber being in fluid communication with a first side of said drive piston;a second chamber in said cylinder containing a hydraulic fluid, said second chamber being in fluid communication with a second side of said drive piston and a first side of said working piston;a port for injecting said first fluid into said first chamber;wherein when said first fluid is injected through said port into said first chamber, pressure is applied to said first side of said drive piston and said drive piston is urged in a first direction, thus urging hydraulic liquid from said second chamber against said first side of said working piston, thereby actuating said shoring strut.