Npk Construction Equipment, Inc.

Robert Boschgmbh

Roger A Webel

Frank C Karsten

Scott C Graham

Daniel S Lacey

Richard F Sailer, Jr

Evan D Bialosky

Salvatore L Zingales, Sr

A new means of achieving a valve float position in a closed centered hydraulic control valve. The valve has a main spool position whereby pressure compensator load sense control pressure is drained to tank through the main spool. Secondly, a pin acts on the pressure compensator to prevent the main pump flow from reaching the main section spool. Finally, the new spool position adds a connection from the consumer to tank, enabling a float position.

Hydraulic control valve

A control system for a heavy duty hydraulic hammer reduces blank firing of the hammer. The control system provides a reduced flow of hydraulic fluid to the hammer for a selected period of time upon actuation of the hammer and then provides full hydraulic flow increasing the frequency of impacts to full rated values.

Slow start control for a hydraulic hammer

A control system and method of using a control system for a thumb on an excavator allows the thumb to follow a workpiece held in a bucket when the bucket moves. The thumb control circuit is activated by the press of a button and thereafter maintains a constant reduced close fluid pressure of the extend port of the thumb cylinder until the open control is actuated.

Control system for an excavator thumb and a method of controlling an excavator thumb

Growing community of inventors

Copley, OH, United States of America

Roger A Webel