Pilot operated hydraulic control valve

Claim 2

A pilot operated control valve comprising: a housing defining an inlet and an outlet; a main valve member movable in the housing and cooperating therewith to define a pilot chamber, pressure in the pilot chamber acting directly on the main valve member to move it to control fluid communication between the inlet and the outlet, the main valve member and the housing cooperating to define a damping chamber therebetween; a damping orifice communicating the damping chamber with the pilot chamber, the damping orifice comprising a single passage which extends through a portion of the main valve member, there being no other passage communicated directly with the damping chamber; and pilot valve means for controlling the pilot pressure, the pilot valve means including a pilot valve member movable with respect to the main valve member.

Claim 3

The control valve of claim 1, wherein: the housing defines a valve bore therein with a larger diameter portion and a smaller diameter portion joined by an annular shoulder; and the main valve member comprises a cylindrical body with a larger diameter portion and a smaller diameter portion joined by an annular wall, the larger diameter body portion being slidably and sealingly received in the larger diameter valve bore portion and the smaller diameter body portion being slidably and sealingly received in the smaller diameter bore portion, the shoulder, the wall, the large diameter bore portion and the smaller diameter body portion cooperating to enclose the damping chamber therebetween.

Claim 4

The control valve of claim 2, wherein: the damping orifice extends radially through the smaller diameter body portion of the main valve member.

Claim 5

The control valve of claim 1, further comprising: a resilient means connected between the pilot and main valve members so that upon movement of the pilot valve member, a mechanical force is applied via the resilient means to the main valve member, said mechanical force tending to move to the main valve member so as to follow the movement of the pilot valve member.

Claim 6

The control valve of claim 1, wherein the pilot valve means comprises: a pilot passage extending through the main valve member for communicating the outlet with the pilot chamber; and a land carried on the pilot valve member, the land being slidably received by the main valve member and movable therein to control fluid communication through the pilot passage.

Claim 7

The control valve of claim 5, wherein: the main valve member encloses an inlet chamber communicated with the inlet; and the pilot passage is comprised of separate first and second passages extending through the main valve member between the pilot chamber and the inlet chamber, and a third passage intersecting the first passage and communicating the first passage with the outlet, the land being movable to open and close communication between the third passage and the inlet chamber via a portion of the first passage.

Claim 8

The control valve of claim 6, wherein: the pilot valve member includes at least one further land, said at least one further land being received by the first passage and slidably and sealingly engaging a wall of the first passage to close communication between the third passage and the pilot chamber via the first passage.

Claim 9

The control valve of claim 7, wherein: the first passage extends along a central axis of the main valve member.

Claim 10

The control valve of claim 6, wherein: the second passage is spaced apart from and extends generally parallel to the first passage.

Claim 11

A pilot operated control valve comprising: a housing defining an inlet and an outlet; a main valve member movable in the housing and cooperating therewith to define a pilot chamber, the main valve member being movable in response to pressure in the pilot chamber to control fluid communication between the inlet and the outlet; pilot valve means for controlling the pilot pressure, the pilot valve means including a pilot valve member movable with respect to the main valve member; a first spring coupled between the housing and the pilot valve member and biased to urge the pilot valve member and the main valve member in a direction closing communication between the inlet and the outlet; a second spring coupled between the pilot valve member and the main valve member and biased to urge the main valve member in a direction which opens communication between the inlet and outlet; a third spring coupled between the pilot valve member and the main valve member and biased to urge the main valve member in a direction which closes communication between the inlet and the outlet; a spring guide coupled to the third spring and engageable with the pilot valve member to transmit forces between the pilot valve member and the main valve member; and an abutment engageable with the spring guide to limit the motion thereof so that the pilot valve member disengages from the spring guide after the pilot valve member moves a predetermined distance.

Claim 12

A pilot operated control valve comprising: a housing defining an inlet and an outlet; a main valve member movable in the housing and cooperating therewith to define a pilot chamber, the main valve member being movable in response to pressure in the pilot chamber to control fluid communication between the inlet and the outlet; pilot valve means for controlling the pilot pressure, the pilot valve means including a pilot valve member movable with respect to the main valve member; a first spring coupled between the housing and the pilot valve member and biased to urge the pilot valve member and the main valve member in a direction closing communication between the inlet and the outlet; a second spring coupled between the pilot valve member and the main valve member and biased to urge the main valve member in a direction which opens communication between the inlet and outlet; a third spring coupled between the pilot valve member and the main valve member and biased to urge the main valve member in a direction which closes communication between the inlet and the outlet; a spring guide coupled to the third spring and engageable with the pilot valve member to transmit forces between the pilot valve member and the main valve member; and an abutment engageable with the spring guide to limit the motion thereof so that the pilot valve member disengages from the spring guide after the pilot valve member moves a predetermined distance.

Claim 13

The control valve of claim 10, wherein: the abutment is formed by a surface of the main valve member.

Claim 14

A pilot operated control valve comprising: a housing defining an inlet and an outlet; a main valve member movable in the housing and cooperating therewith to define a pilot chamber, the main valve member being movable in response to pressure in the pilot chamber to control fluid communication between the inlet and the outlet, the main valve member and the housing cooperating to define a damping chamber therebetween, the main valve member enclosing an inlet chamber communicated with the inlet; pilot valve means for controlling the pilot pressure, the pilot valve means including a pilot valve member movable with respect to the main valve member, the pilot valve means comprising a pilot passage extending through the main valve member for communicating the outlet with the pilot chamber, and a land carried on the pilot valve member, the land being slidably received by the main valve member and movable therein to control fluid communication through the pilot passage; a damping orifice communicating the damping chamber with the pilot chamber; and the pilot passage is comprised of separate first and second passages extending through the main valve member between the pilot chamber and the inlet chamber, and a third passage intersecting the first passage and communicating the first passage with the outlet, the land being movable to open and close communication between the third passage and the inlet chamber via a portion of the first passage.

Claim 15

A pilot operated control valve comprising: a housing defining an inlet and an outlet; a main valve member movable in the housing and cooperating therewith to define a pilot chamber, the main valve member being movable in response to pressure in the pilot chamber to control fluid communication between the inlet and the outlet, the main valve member and the housing cooperating to define a damping chamber therebetween, the main valve member enclosing an inlet chamber communicated with the inlet; pilot valve means for controlling the pilot pressure, the pilot valve means including a pilot valve member movable with respect to the main valve member, the pilot valve means comprising a pilot passage extending through the main valve member for communicating the outlet with the pilot chamber, and a land carried on the pilot valve member, the land being slidably received by the main valve member and movable therein to control fluid communication through the pilot passage; a damping orifice communicating the damping chamber with the pilot chamber; and the pilot passage is comprised of separate first and second passages extending through the main valve member between the pilot chamber and the inlet chamber, and a third passage intersecting the first passage and communicating the first passage with the outlet, the land being movable to open and close communication between the third passage and the inlet chamber via a portion of the first passage.

Claim 16

The control valve of claim 12, wherein: the pilot valve member includes at least one further land, said at least one further land being received by the first passage and slidably and sealingly engaging a wall of the first passage to close communication between the third passage and the pilot chamber via the first passage.

Claim 17

The control valve of claim 13, wherein: the first passage extends along a central axis of the main valve member.

Claim 18

The control valve of claim 12, wherein: the second passage is spaced apart from and extends generally parallel to the first passage.