US 2002/0170423 A1Published application

Hydraulic tool with an oc/cc selector

AssigneeThe Stanley Works

InventorTheodore J. Schultz

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Abstract

A hydraulic tool is operable in an open center (OC) and a closed center (CC) mode and includes a cylinder and a piston within the cylinder. The piston defines a drive chamber and a retract chamber. A valve spool selectively supplies and exhausts hydraulic fluid to and from the drive chamber and the retract chamber. An oil tube is coupled to the valve spool and extends through the piston and is in communication with the retract chamber. The oil tube includes at least one hole that can selectively communicate the drive chamber and the retract chamber. A selector sleeve is provided for switching between the OC and CC modes. In the OC mode when the tool is in the neutral mode, the valve spool is configured to supply the hydraulic fluid through the oil tube to the retract chamber such that movement of the piston can allow communication between the retract chamber and the drive chamber through the at least one hole in the oil tube.

Claims30

Dependent claims

A hydraulic tool switchable between an open center mode and a closed center mode and having a work mode and a neutral mode, comprising:

a cylinder defining a chamber;
a piston within the chamber and operable in the neutral mode and the work mode, the piston defining a drive chamber and a retract chamber within the chamber;
a valve operable to selectively supply hydraulic fluid to the drive chamber to thereby drive the piston to a first position when the tool is in the work mode, and to selectively supply the hydraulic fluid to the retract chamber to thereby move the piston to a second position when the tool is in the neutral mode;
a fluid inlet and a fluid outlet in fluid communication with the valve;
an oil tube in fluid communication with the valve and extending through the piston and being in communication with the retract chamber, the oil tube including opposite ends and at least one hole between said ends;
and
a mode selector being positionable between a first position in which the tool can operate in the open center mode in which the tool can utilize a constant volume fluid delivery source, and a second position in which the tool can operate in the closed center mode in which the tool can utilize a constant pressure fluid delivery source;
wherein, in the open center work mode the valve is configured to supply the hydraulic fluid through the oil tube to the drive chamber to drive the piston to the first position, and wherein when the tool is moved to the neutral mode, the valve is configured to supply the hydraulic fluid through the oil tube to the retract chamber such that movement of the piston to the second piston can allow communication between the inlet and outlet through the at least one hole in the oil tube.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/858,905Filed 17 May 2001
Published: 21 Nov 2002
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

F15B 13/021
Fluid distribution or supply devices characterised by their adaptation to the control of servomotors: valves for interconnecting the fluid…
F15B 11/024
Systems essentially incorporating special features for controlling the speed or the actuating force of an output member: by means of differential…
F15B 15/202
Other details , e.g. assembly with regulating devices: externally-operated valves mounted in or on the actuator
F15B 21/082
Servomotor systems incorporating electrically operated control means: with different modes