Abstract: The hydraulic tool of this invention includes a pressure chamber into which a fluid is pumped. A pump chamber has an inlet port and outlet port at opposite ends thereof and a pump plunger extends into the chamber with an annular space around it. An annular shoulder is provided on either the chamber or the plunger and a seal ring or sleeve fits slidably on the other component to seal against the shoulder. A spring biases the seal ring against the shoulder, and when the pump is extended to force fluid out the outlet port, the pressure in the chamber augments the spring force. Then, when the rod is retracted to create a void, fluid in the reservoir forces the seal ring or sleeve away from the seat surface to enter the inlet port.

Abstract: The disclosure is of a mechanical riveter wherein rivet-gripping jaws are pulled through a slideway by means of a pull rod. Each of a pair of links is pivoted between one of a pair of squeezable handles and a yoke carried on the pull rod. Means are provided to adjust the position of the yoke along the rod, thus fixing the length of the stroke and the mechanical advantage of the tool.