Float controlled hydraulic leveler

Claim 1

In an apparatus for hydraulically correcting misalignment between two members adapted to rotate with respect to each other, the combination comprising: a housing assembly sealed to encapsulate a fluid under pressure, said housing assembly including means for attachment to one of said members and having a first reference line adapted to rotate in concert with said one member when it moves; fluid distribution means having first and second conduits for transmitting said fluid between said housing assembly and an actuator means adapted to rotate said one member in one direction in response to a change in fluid pressure in one conduits and in the other direction in response to a change in fluid pressure in the other conduit; valve means for selectively changing the fluid pressure in said first and second conduits, said valve means including first and second members adapted to move relative to each other, said first member being rigidly attached to said housing assembly so as to be fixed with respect to said first reference line, said second member containing a second reference line disposed in a pre-determined position with respect to said first reference line and adapted to move with respect to said first reference line when said first and second members move with respect to each other, and said first and second members including port means for opening a fluid access passage to one of said conduits when said reference lines move with respect to each other in one direction and for opening a fluid access passage to the other of said fluid conduits when said reference lines move with respect to each other in the other direction; and control means cooperating with said valve means and having float means for maintaining said second reference line in pre-determined orientation with respect to the earth and said first member is fixed with respect to said housing assembly, while said second member is free to move with respect to said first member and said float means is attached to said second member and said port means includes input and output apertures in said first member and grooves in said second member adapted to equally bridge said input and output apertures when said second reference line is disposed in said pre-determined position with respect to said first reference line and said input apertures include two pressure ports, said output apertures include four control ports and two exhaust ports, and each groove links a pressure port or exhaust port to two control ports.