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US 4,489,471 AGranted
Hydraulic pulling tool
AssigneeGregory Tool Systems, Inc.
InventorJack T. Gregory
Life of this patent
Estimating the term…
Abstract
A hydraulic pulling tool comprising a piston slidable within a cylinder and having a co-axial bore therein. Lateral passages open from the bore through the piston to the leading face thereof and a screw piston is pushed in the bore by threading a screw pusher so that the hydraulic fluid in the bore is forced out into the cylinder to retract the piston. For a blind riveter, a pair of jaws is driven by a pusher piston also carried at the leading end of the bore so that the build up of pressure causes the jaws to grip a blind rivet firmly.
Claims4
A hydraulic pulling tool comprising:
- a cylinder;
- a main piston slidable in said cylinder;
- an axial bore extending into said main piston;
- a plunger slidable in said bore;
- at least one port opening from said bore to the leading face of said main piston;
- an extension on the leading end of said main piston extending through the head of said cylinder;
- work-piece gripping means on said extension;
- mechanical means for forcing said plunger into said bore;
- and
- means biasing said main piston toward said cylinder head.
7 more elements
Dependencies are inferred from the claim text.