초록 ▼

A pneumatic/hydraulic shoring strut is disclosed for bracing walls in various situations. The shoring strut is provided with features that allow it to be infinitely adjustable and self-locking. In a preferred embodiment, the strut contains an internal biasing member that urges contraction when pneum

A pneumatic/hydraulic shoring strut is disclosed for bracing walls in various situations. The shoring strut is provided with features that allow it to be infinitely adjustable and self-locking. In a preferred embodiment, the strut contains an internal biasing member that urges contraction when pneumatic pressure is released. More particularly, the pneumatic/hydraulic shoring strut of the present invention is composed of an inner and outer cylinder which form an annular recess therebetween. The cylinders are mounted in first and second caps and an annular drive piston is positioned within the annular recess, creating first and second chambers. A port for injecting air into the first chamber is mounted on the outer cylinder and hydraulic fluid is sealed in the second chamber. A channel is provided in one of the caps providing fluid communication between the second chamber and an interior cavity located within the inner cylinder where a working piston is reciprocatingly mounted. The channel has a unidirectional flow control valve and a releasable flow restriction control mounted therein thereby facilitating the self-locking feature of the strut.

대표청구항 ▼

[ What is claimed is:] [1.] 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

[ What is claimed is:] [1.] 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.