Hydraulic control valve with flow-sensitive unlatching mechanism

Claim 2

A hydraulic control valve for directing fluid from a fluid energy source to a working cylinder having a reciprocating piston and comprising: a housing: a selectively movable valve spool means within said housing; a latching mechanism connected to said valve spool means and effective to hold it in a selected position; a fluid pressure actuated latching release means effective to release said latching mechanism; and fluid-flow-sensitive valve means arranged to control the fluid pressure directed to said latching release means and responsive to fluid flow to the working cylinder and effective to prevent the actuation of said latching release means until the cessation of fluid flow to said cylinder when said reciprocating piston reaches a limit of its stroke.

Claim 3

The control valve of claim 1 wherein: said valve spool is formed with an axial bore for directing fluid energy to said latching release means upon cessation of flow through said valve.

Claim 4

a pressure-actuated release means for releasing said detent means, and

Claim 5

a pressure-actuated release means for releasing said detent means, and

Claim 6

flow-sensitive valve means on said control valve for directing fluid to said release means upon cessation of flow through said control valve so as to release said detent means whereby the spool may return to a neutral position.

Claim 7

flow-sensitive valve means on said control valve for directing fluid to said release means upon cessation of flow through said control valve so as to release said detent means whereby the spool may return to a neutral position.

Claim 8

The control valve of claim 2 wherein: said latching release means includes a longitudinally movable piston that is responsive to the fluid energy within said bore to unlatch said latching mechanism.

Claim 9

The control valve of claim 3, wherein: said fluid-flow-sensitive valve means includes a fluid-flow-restricting land- and spring-bias means acting in opposition to fluid flow past said land and effective to move said valve means when fluid flow therepast ceases so as to permit fluid energy to be transmitted through said axial bore to actuate said latching release means.

Claim 10

The control valve of claim 4 wherein: said fluid-flow-sensitive valve means includes a valve sleeve surrounding said valve piston, said valve sleeve being effective to prevent the entry of fluid into said bore while fluid is flowing past said flow-restricting land.

Claim 11

A hydraulic control valve and latching mechanism for use in a hydraulic system adapted to direct fluid under pressure from a fluid source to a movable piston having a limited stroke and comprising: a housing; a cylindrical spool valve longitudinally movable within said housing into a selectable position for communicating the fluid source with the piston and held in such position by said latching mechanism; a fluid-pressure-actuated release means effective to release said latching mechanism; and a flow responsive cylindrical valve sleeve surrounding said spool valve and longitudinally movable thereon in response to fluid flow through said spool valve and arranged to control said release means to effect release of the latching mechanism only upon cessation of said fluid flow.

Claim 12

A hydraulic control valve and latching mechanism for use in a hydraulic system adapted to direct fluid under pressure from a fluid source to a movable piston having a limited stroke and comprising: a housing; a cylindrical spool valve longitudinally movable within said housing into a selectable position for communicating the fluid source with the piston and held in such position by said latching mechanism; a fluid-pressure-actuated release means effective to release said latching mechanism; and a flow responsive cylindrical valve sleeve surrounding said spool valve and longitudinally movable thereon in response to fluid flow through said spool valve and arranged to control said release means to effect release of the latching mechanism only upon cessation of said fluid flow.

Claim 13

The hydraulic control valve of claim 6 including: fluid conduit means in communication with said latching release means and effective to direct fluid from the source thereto for unlatching, said valve sleeve being effective to preclude said fluid flow to said latching release means until fluid flow to said piston ceases.

Claim 14

The hydraulic control valve of claim 7, said latching release means includes a longitudinally movable piston contained in said valve spool and responsive to fluid pressure from the source to unlatch the latching mechanism.

Claim 15

A hydraulic control system for operating a fluid pressure-actuated hydraulic cylinder having a piston movable through a limited stroke and comprising: a source of fluid energy; a spool valve formed with fluid-directing conduits and ports and selectively movable into at least one position for directing fluid from said source to the piston; a fluid pressure releasable latching mechanism attached to said spool valve and effective to latch it in a selected position; and a movable fluid-flow-responsive valve interposed between said source and the piston and effective to block the application of fluid pressure to said latching mechanism until the piston reaches the end of its stroke and fluid flow thereto ceases.

Claim 16

A hydraulic control system for operating a fluid pressure-actuated hydraulic cylinder having a piston movable through a limited stroke and comprising: a source of fluid energy; a spool valve formed with fluid-directing conduits and ports and selectively movable into at least one position for directing fluid from said source to the piston; a fluid pressure releasable latching mechanism attached to said spool valve and effective to latch it in a selected position; and a movable fluid-flow-responsive valve interposed between said source and the piston and effective to block the application of fluid pressure to said latching mechanism until the piston reaches the end of its stroke and fluid flow thereto ceases.

Claim 17

The hydraulic control system of claim 9 wherein: said fluid flow responsive valve comprises a valve sleeve surrounding said spool valve and formed with a fluid-flow-restricting land that tends to restrict the flow of fluid from said source to the piston and is effective when moved by the force due to fluid flow to block the application of fluid pressure to the latching mechanism.

Claim 18

The hydraulic control system of claim 10 and including: a compressable spring that is compressed by the movement of said valve sleeve and is effective to return said valve sleeve when fluid flow to the piston ceases so as to allow the application of fluid pressure to the latching mechanism.

Claim 19

In a directional flow control valve having a reciprocable spool and porting for selectively directing fluid energy from a source to a motor, the improvement comprising:

Claim 20

In a directional flow control valve having a reciprocable spool and porting for selectively directing fluid energy from a source to a motor, the improvement comprising:

Claim 21

An apparatus as defined in claim 12 in which said flow-sensitive means comprises a biased sleeve sensitive to flow and having ports therein for directing fluid to said release means upon cessation of flow.