| US 7,472,638 B2 | ||
| Hydraulic system with an actuator having independent meter-in meter-out control | ||
| Thomas J. Hajek, Jr., Lockport, Ill. (US); and Vincent Triffaux, Strepy-Bracquegnies (Belgium) | ||
| Assigned to Caterpillar Inc., Peoria, Ill. (US) | ||
| Filed on Oct. 14, 2005, as Appl. No. 11/249,508. | ||
| Application 10/751589 is a division of application No. 09/406893, filed on Sep. 28, 1999, granted, now 6,691,604. | ||
| Application 11/249508 is a continuation of application No. 10/751589, filed on Jan. 05, 2004, granted, now 6,976,418. | ||
| Prior Publication US 2006/0027092 A1, Feb. 09, 2006 | ||
| Int. Cl. F15B 11/024 (2006.01) | ||
| U.S. Cl. 91—436 [91/439; 91/464] | 11 Claims |
| 5. An actuator control circuit to control an ingress of fluid into and an egress of fluid away from an actuator, the actuator
including a first and a second port, the actuator control circuit comprising:
a source of pressurized fluid configured to direct fluid from a reservoir to at least one of the first and second ports of
the actuator;
a first electro-hydraulic valve arrangement, wherein the source of pressurized fluid being fluidly connected with the first
port of the actuator through the first electro-hydraulic valve arrangement;
a second electro-hydraulic valve arrangement, wherein the first port of the actuator being fluidly connected with the reservoir
through the second electro-hydraulic valve arrangement;
a third electro-hydraulic valve arrangement, wherein the second port of the actuator being fluidly connected with the reservoir
through the third electro-hydraulic valve arrangement; and
a control valve, wherein the source of pressurized fluid being fluidly connected free of non-return valves with the second
port of the actuator through the control valve,
wherein the control valve is operable to: i) direct fluid from the source of pressurized fluid to the second port of the actuator,
and ii) regeneratively direct fluid from the second port of the actuator through the first electro-hydraulic valve arrangement
to the first port of the actuator,
wherein the control valve is a poppet valve arrangement having a poppet valving element movable between a flow blocking position
and a flow passing position, a fluid control chamber defined behind the poppet valving element, a resolver arrangement operative
to select the higher pressure fluid between upstream and downstream of the poppet valving element and controllably direct
the higher pressure to the control chamber, and a variably controlled orifice operative to control the pressurized fluid within
the control chamber by venting fluid therefrom to a lower pressure area.
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