Hydraulic control valve for a one-sided operating differential cylinder having five control edges

Patent metadata

Field	Value
Publication number	US-9273664-B2
Application number	US-201113030376-A
Country	US
Kind code	B2
Filing date	Feb 18, 2011
Priority date	Feb 18, 2011
Publication date	Mar 1, 2016
Grant date	Mar 1, 2016

Abstract

A hydraulic control valve to control a double-acting working cylinder having a piston with a piston rod on one side, at least four external connections, and a device to feed the fluid forced from the small stroke space of the working cylinder into the large stroke space while the piston rod is moving out, and further for independent switching of the working cylinder from the work stroke to slow movement with a subsequent holding state to release pressure from the small stroke space, and wherein a connection of the small stroke space to the tank can be switched on. The control valve has five control edges, with two separate line paths formed to feed the fluid forced out of the small stroke space back with a back-feed control edge and a pressure-release control edge is formed to release pressure from the small stroke space to the tank.

First claim

What is claimed is:

1. A hydraulic control valve to control a double-acting working cylinder including a piston with a piston rod on one side, the hydraulic control valve comprising
a valve housing having formed therein at least four external connections with assigned ring channels formed in the valve housing, the external connections including
a pump connection (P);
a connection (A 1 ) for a supply and discharge line to the large stroke space of the working cylinder;
a connection (B) for a supply and discharge line to the small stroke space of the working cylinder; and
a tank connection (T 1 ) for a connection to the tank; and

a control piston having a piston collar with control edges arranged on it, by which the external connections can be connected to one another in two positions of the control piston in such a way that during the work stroke of the working cylinder, a back feed of the fluid forced out of the small stroke space into the large stroke space occurs while the piston rod is moving out, and for stroke-independent switching of the working cylinder from the work stroke to slow movement with a subsequent holding state to release pressure from the small stroke space of the working cylinder, a connection of the small stroke space to the tank can be switched on, wherein the control piston has at least three piston collars with five control edges formed on it and the valve housing has two separate line paths for the fluid forced from the small stroke space during the work stroke of the piston, of which a first line path, established for the back feed, connects the supply and discharge line connected to the small stroke space through a recess acting as a back feed control edge to the large stroke space of the working cylinder, and the second line path, formed to connect the small stroke space to the tank, leads to a pressure-release control edge formed on an assigned piston collar of the hydraulic control valve, whereby the recess forming the pressure-release edge in the assigned piston collar is designed for the fluid stream forced out of the small stroke space of the working cylinder and is dimensioned smaller than the recesses of the piston collar forming the other control edges.

2. A hydraulic control valve according to claim 1 , wherein the supply and discharge line that connects to the small stroke space is branched in a branching into two line strands to which the first line strand is assigned to the piston collar having the back-feed control edge and the second line strand is assigned to the piston collar having the pressure-release control edge, whereby in the position of the control piston for the work stroke of the cylinder, the back-feed control edge creates the connection of the first line strand to the large stroke space of the working cylinder, and a check valve with a pass through device is included in the line strand to the large stroke space and the pressure-release control edge creates the connection of the second line strand to the tank through an externally controllable lock valve to switch the discharge line that accepts the working cylinder.

3. A hydraulic control cylinder according to claim 2 , wherein the line strand is assigned to an additional ring channel formed in the valve housing, one of which ring channels is assigned to the piston collar forming the back-feed control edge to block or connect the line strand having the check valve opening into the ring channel to the large stroke space and the other ring channel is assigned to the piston collar forming the pressure-release edge to block or connect the discharge line having the lock valve going from the ring channel to the line strand leading to connection (B) for a supply and discharge line to the small stroke space of the working cylinder.

4. A hydraulic control valve according to claim 3 , wherein the branching of the supply and discharge line connected with the large stroke space, the two line strands, and the discharge line having the lock valve to the tank are formed Inside the valve housing.

5. A hydraulic control valve according to claim 4 , wherein the connection of the additional ring channels to the large stroke space is created by means of another Internal ring channel through the back-feed control edge to be connected and a bridge going from the inside of the housing to the ring space belonging to the connection (A 1 ), whereby a check valve is included in the bridge with a pass-through device directed toward the connection (A 1 ).

6. A hydraulic control valve according to claim 3 , wherein the hydraulic control valve has a further external connection (A 2 ) and the connection of the additional ring channel to the large stroke space is created by means of a ring space assigned to the further external connection (A 2 ) through the back-feed control edge to be connected and by means of a connection line leading to the further external connection (A 2 ) and to the large stroke space of the working cylinder.

7. A hydraulic control valve according to claim 6 , wherein the hydraulic control valve has another external connection (T 2 ), and a fourth piston collar with an additional sixth control edge is provided to connect the connection (A 2 ) to connection (T 2 ).

8. A hydraulic control valve according to claim 3 , wherein the branching of the discharge line to the tank having the connected supply and discharge line arranged to the small stroke space, the two line strands, and the lock valve are arranged outside the valve housing and the hydraulic control valve has a further external connection (A 2 ) and another external connection (T 2 ), and that the line strand having the check valve leads from the branching to a seventh external connection formed on the outside and connection (B) connected to the ring space and the connection (T 2 ) connected to the additional ring space controlled by the pressure release control edge is connected through the discharge line to the tank having the lock valve.

9. A hydraulic control valve according to claim 8 , wherein the hydraulic control valve has an eighth external connections (T 3 ), whereby connection (T 2 ) can be connected through a fourth piston collar to an additional sixth control edge to connection (A 2 ) and connection (T 3 ) can be connected to the ring space controlled by the pressure-release control edge and through the discharge line having the lock valve to the tank.

10. A hydraulic control valve according to claim 7 , wherein the external connections (A 2 , T 2 ) are adjacent to connection (B) with respect to the standard connections (T 1 , A 1 , P, B) and the additional ring spaces in the valve housing are arranged between connection (B) and connection.

11. A hydraulic control valve according to claim 7 , wherein the connections (A 2 , T 2 ), are arranged adjacent to connection with respect to the standard connections (T 1 , A 1 , P, B), and an additional ring space lying outside next to the ring space belonging to connection (B) and the second additional ring space is arranged next to the ring space belonging to connection.

Assignees

• Scheffel Gerd
• Parker Hannifin Corp

Inventors

• Scheffel Gerd

Classifications

• Y02E10/226

  Cross-Sectional Technologies · mapped topic

• F03B15/00 Primary

  Controlling (controlling in general G05 {; regulation of plants characterised by the use of siphons F03B13/086}) · CPC title

• Y02E10/20

  Hydro energy · CPC title

• Y10T137/8593

  Systems · CPC title