GB1231670A - - Google Patents

Abstract

1,231,670. Fluid pressure jacks. FICHTEL & SACHS A.G. 5 May, 1969 [7 May, 1968], No. 22702/69. Heading B8J. [Also in Division F2] A pneumatic or hydropneumatic piston-andcylinder spring may be mechanically locked in any relative position of piston and cylinder by operating a device 6 inside the cylinder 1 in the vicinity of the pisron 2 which jams part 7 of the piston against the cylinder wall. As shown, the piston is both mechanically and fluidically locked relative to the cylinder, because of the position of the operating device 6, which both causes clamp pins 10 to press a clamp ring 7 against the wall of the cylinder, and closes the through-piston fluid passages 11. To unlock, an operating bar is pressed in and the device 6 moves down, thus releasing both locks. The piston 2 will then rise owing to the lower surface of the piston having a larger area, or can be pushed further into the cylinder if required, and then relocked by releasing the operating bar 5, the operating device 6 then rising into its locking position because of the excess pressure. In Fig. 2 (not shown), the piston may be mechanically locked only. As the piston-rod is rotated relative to the cylinder, it screws into or out of the piston, thus raising or lowering the operating device relative to the piston. In Fig. 3 (not shown), the piston may be both mechanically and fluidically locked and is provided with slits.