Hydraulic log splitter
AssigneeGregory Tool Systems, Inc.
InventorJack T. Gregory
Life of this patent
Estimating the term…
Abstract
A force-delivering tool such as a log splitter wherein a pusher member carried on a cylinder is forced against a blade carried on a frame to which the piston is secured. The cylinder is driven relative to the piston by means of a reciprocating plunger carrying a cup on the end that forces fluid past a one-way valve ahead of the piston. Oil is pressurized by both the bottom of the cup and its annular end but, when resistance is encountered to build up pressure, a relief valve evacuates the annular chamber so that all the force is concentrated in the area at the bottom of the cup. The entire actuating valve may be backed away to relieve pressure as desired or at the completion of a desired stroke.
Claims12
A hydraulic force-delivering tool comprising:
- a hydraulic cylinder having a cylinder head at one end thereof;
- a piston slidably received in said cylinder;
- an inlet opening into said cylinder between said piston and said cylinder head;
- and
- a hydraulic actuator pump;
- said hydraulic actuator pump comprising:
- a valve body having a cylindrical bore therein;
- a forward end of said valve body connected to said inlet to seal therearound;
- means forming a flow passageway through said forward end of said valve body;
- a main power check valve in said flow passageway forming means enabling flow only outward of said valve body;
- a hollow plunger movable axially in said bore;
- drive means operative when actuated to reciprocate said plunger;
- a cylindrical cup carried on the forward end of said plunger and slidable in said cylindrical bore;
- a cylindrical tubular guide in said valve body extending rearward from said flow passageway forming means and slidably receiving said cup;
- said bore being larger than said tubular guide to form an annular space around said tubular guide ahead of said cup;
- a hydraulic reservoir around said valve body;
- a first lateral inlet port in said valve body opening into said bore;
- a second lateral inlet port in said hollow plunger;
- first-stage load port means opening through the bottom of said cylindrical cup;
- a first-stage one-way check valve engageable with said first stage port means and enabling inward flow only therethrough;
- load duct means from within said hollow plunger to said first-stage load port means;
- a valve seat in said load duct means;
- a high volume check valve engageable with said valve seat to enable inward flow only;
- second stage duct means from said load duct means to said annular spaces, and
- pressure responsive means inactivating said high volume check valve to bypass same in response to an increase in pressure in said load duct means above a predetermined level.
Dependencies are inferred from the claim text.