US3785157A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flow control dump valve
Assignee: Deere and Co
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Filing: 1972-11-24
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Granted: 1974-01-15
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Expires: 1992-11-24
Abstract
Abstract The wheel motor of a hydrostatic drive system is coupled to the wheel through a pressure responsive clutch which disconnects the motor from the wheel during periods when fluid under pressure is not supplied to the motor. A flow control dump valve is built into the clutch actuator and regulates a specific rate of flow through the actuator from zero to lock-up pressure. The flow control dump valve blocks all flow through the actuator above lock-up pressure. The flow control dump valve provides a controlled bleed for purging of air and sumping of oil which leaks past the control valve below lock-up pressure. The sumping of oil below lock-up pressure ensures complete release of the clutch when fluid pressure is not supplied to the motor.
Inventors
- 👤 C Kittle
- 👤 S Moon
- 👤 K Spencer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:18
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/4174; B; B60; B60K; B60K17/00; B60K17/04; B60K17/043; B60K17/046; B60K7/00; B60K7/0015; F16H39/00; F16H39/02; F16H47/00; F16H47/02; F16H47/04; B60K2007/0038; B60K2007/0092; F16H2047/045
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
157 words
In a hydraulic circuit including a pump, a hydraulic function, and hydraulic circuit means interconnecting the pump and function and including valve means for selectively blocking fluid flow from the pump to the function, means for bleeding fluid from the hydraulic circuit means between the function and valve when fluid flow is blocked from the pump to the function comprising: restricted passage means in communication with thE circuit means between the function and valve normally providing limited fluid flow from the circuit means to a reservoir, and flow controlled valve means associated with the restricted passage means responsive to a predetermined pressure drop less than the pressure normally supplied to the function by the pump across the restricted passage means to block the flow of fluid through the restricted passage means whereby the flow controlled valve means prevents bleeding of fluid from the circuit means when fluid under pressure from the pump is supplied to a motor.
Claim 2
Dependent Claim
157 words
In a hydraulic circuit including a pump, a hydraulic function, and hydraulic circuit means interconnecting the pump and function and including valve means for selectively blocking fluid flow from the pump to the function, means for bleeding fluid from the hydraulic circuit means between the function and valve when fluid flow is blocked from the pump to the function comprising: restricted passage means in communication with thE circuit means between the function and valve normally providing limited fluid flow from the circuit means to a reservoir, and flow controlled valve means associated with the restricted passage means responsive to a predetermined pressure drop less than the pressure normally supplied to the function by the pump across the restricted passage means to block the flow of fluid through the restricted passage means whereby the flow controlled valve means prevents bleeding of fluid from the circuit means when fluid under pressure from the pump is supplied to a motor.
Claim 3
Dependent Claim
44 words
The invention as set forth in claim 1 wherein the hydraulic function includes a movable piston member, the restricted passage means extends through the movable piston member, and the flow controlled valve means is located within a chamber provided in the movable piston member.
Claim 4
Dependent Claim
122 words
The invention as set forth in claim 2 wherein the chamber provided in the movable piston member is cylindrical and has one end open to the circuit means, fluid passage means extends from the second end of the chamber to a fluid reservoir, a secondary piston is mounted in the chamber for limited reciprocal movement, a ball member is positioned in the chamber between the second end thereof and the secondary piston for engagement with a valve seat formed by the juncture between the chamber and fluid passage means, spring means normally urge the ball member away from the seat into engagement with the secondary piston, and a small bore extends through the secondary piston from one end thereof to the other.
Claim 5
Dependent Claim
147 words
For use in a hydraulic circuit including a pump, a hydraulic function, and a directional flow control valve between the pump and function, a flow controlled dump valve comprising: a valve body having a cylindrical chamber therein with one end open to the hydraulic circuit between the function and directional flow control valve; fluid passage means extending from a second end of the chamber to a fluid reservoir; the juncture between the chamber and fluid passage means forming a valve seat; a piston reciprocally mounted in the chamber; a ball valve member in the chamber between the piston and valve seat; yieldable force-applying means normally urging the ball valve member away from the seat into engagement with the piston; and a restricted fluid passageway provided through the piston to permit limited fluid flow from the first end of the chamber to the second end of the chamber.
Claim 6
Dependent Claim
147 words
For use in a hydraulic circuit including a pump, a hydraulic function, and a directional flow control valve between the pump and function, a flow controlled dump valve comprising: a valve body having a cylindrical chamber therein with one end open to the hydraulic circuit between the function and directional flow control valve; fluid passage means extending from a second end of the chamber to a fluid reservoir; the juncture between the chamber and fluid passage means forming a valve seat; a piston reciprocally mounted in the chamber; a ball valve member in the chamber between the piston and valve seat; yieldable force-applying means normally urging the ball valve member away from the seat into engagement with the piston; and a restricted fluid passageway provided through the piston to permit limited fluid flow from the first end of the chamber to the second end of the chamber.
Claim 7
Dependent Claim
26 words
The invention as set forth in claim 4 wherein the hydraulic function includes a movable piston member and the movable piston member forms the valve body.
Claim 8
Dependent Claim
129 words
In a piston for applying brakes and clutches and having a first fluid pressure receiving end and a second clamp-up end, the improvement comprising: a cylindrical chamber provided in the piston open to the first end; a fluid passage provided in the piston interconnecting the cylindrical chamber and the second end of the piston; the juncture between the chamber and passage forming a valve seat; a secondary piston slidably mounted in the cylindrical opening; a restricted passage provided through the secondary piston from one end thereof to the other; a ball valve member in the chamber between the secondary piston and the valve seat; and yieldable force-applying means acting on the ball valve member to normally force the ball valve member off the seat and against the secondary piston.
Claim 9
Dependent Claim
129 words
In a piston for applying brakes and clutches and having a first fluid pressure receiving end and a second clamp-up end, the improvement comprising: a cylindrical chamber provided in the piston open to the first end; a fluid passage provided in the piston interconnecting the cylindrical chamber and the second end of the piston; the juncture between the chamber and passage forming a valve seat; a secondary piston slidably mounted in the cylindrical opening; a restricted passage provided through the secondary piston from one end thereof to the other; a ball valve member in the chamber between the secondary piston and the valve seat; and yieldable force-applying means acting on the ball valve member to normally force the ball valve member off the seat and against the secondary piston.
Claim 10
Dependent Claim
31 words
The invention as set forth in claim 6 wherein the secondary piston includes means cooperating with the ball valve member to retain the ball valve member in alignment with the seat.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |