GB791720A - Improvements in or relating to hydraulic hand tools - Google Patents

Abstract

791,720. Jointing by stamping. AMP, Inc. Feb. 23, 1956 [Feb. 24, 1955], No. 5663/56. Class 83 (4). An hydraulic hand tool for crimping an electrical connector on to a conductor comprises a piston 12 carrying a crimping die 22, a ram 42 adapted to withdraw liquid from a reservoir via a non-return valve and apply it via a second non-return valve to the piston, the ram being driven by a pair of handles through toggle linkage, the piston, ram and the handles being coaxial. A spring-loaded ball valve 44 is disposed between the ram chamber and the piston chamber. The reservoir is an elastic fluid container 58 held in place in a barrel 50 by a ring 62 and a breather hole 64 in the barrel permits expansion and contraction of the elastic container. A second spring-loaded ball valve 70 allows liquid flow from the elastic container to the ram chamber 40. A guard 76 prevents the elastic container from blocking the ball valve 70 when the container is partially collapsed. The elastic container is filled through a cap 81 in the barrel 50. A manually operable release valve 108 permits liquid to by-pass valve 44 and flow into the elastic container and an overload-release valve 120 allows liquid to escape into the elastic container when the fluid pressure exceeds a predetermined amount. In operation, the tool is filled with liquid and a terminal is inserted between the dies. The release valve 108 is closed and the handles 94 and 96 are separated to draw liquid from the elastic container into the ram chamber and then closed to raise the ram and force the liquid through the ball valve 44 into the piston chamber to effect the crimping operation. A series of strokes may be necessary and a sudden decrease in the effort required to make a stroke denotes that the crimp is secure and that the overload release valve 120 has opened. To release the tool the release valve 108 is opened by rotating the screw 112.