Caterpillar Inc.

Aleem Junaidi

Pengfei Ma

Tetsuya Yoshino

Aleksandar M Egelja

Matthew James Beschorner

Justin Douglas Speichinger

John R Connolly

Bryan A Johnson

Shogo Tada

Hideki Nakajima

Shuhei Orimoto

Jun Wen

A hoist valve assembly for a work machine cylinder includes a main control valve, a counterbalance valve and a counterbalance shutoff valve. A main control valve raise position connects a head end of the cylinder with a pressurized fluid source and a rod end of the cylinder to a low pressure reservoir to extend the cylinder. The counterbalance valve is between the rod end and the main control valve, is biased to a closed position and has an open position connecting the rod end to the low pressure reservoir. Rod end and head end pressure signals apply force to the counterbalance valve toward the open position. The counterbalance shutoff valve is positioned between the head end and the counterbalance valve, and has a normal position to apply the head end pressure signal to the counterbalance valve and a shutoff position that blocks the head end pressure signal from the counterbalance valve.

Hoist system counterbalance valve signal shutoff

A hydraulic system is disclosed. The hydraulic system may include a source of pressurized fluid; a tank; a hydraulic actuator including a first chamber and a second chamber; a first independent metering valve disposed between and fluidly connected to the source, the tank, and the first chamber of the hydraulic actuator; and a second independent metering valve disposed between and fluidly connected to the source, the tank, and the second chamber of the hydraulic actuator. Each of the first independent metering valve and the second independent metering valve may include a spool and a valve actuator disposed on one side of the spool. The valve actuator may include a push coil, a pull coil, and a force feedback mechanism configured to balance a force of the push coil and the pull coil.

Split spool valve

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Peoria, IL, United States of America

Aleem Junaidi