US5350152A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Displacement controlled hydraulic proportional valve
Assignee: Caterpillar Inc
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Filing: 1993-12-27
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Granted: 1994-09-27
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Expires: 2013-12-27
Abstract
Abstract A displacement controlled hydraulic proportional valve has a spring retainer and a force feedback spring serially disposed between a pilot valve spool and a main valve spool in a control chamber. An arcuate convex end portion on the pilot valve spool extends into a cylindrical pocket in the spring retainer essentially defining a contact point through which force is transferred between the pilot valve spool and the retainer. The point contact minimizes side loading on the pilot valve spool due to buckling of the feedback spring to minimize tendency of the pilot valve spool to stick during operation.
Inventors
- 👤 Eric A. Hutchison
- 👤 John J. Krone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 01:19
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/02; F15B13/04; F15B13/042; F15B13/043; F15B13/0435; F15B13/0433; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/86582; Y10T137/86614
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
200 words
A displacement controlled hydraulic proportional valve having a main valve spool, a control chamber disposed at one end of the main valve spool, a control port communicating with the control chamber, a pilot valve spool in axial alignment with the main valve spool and movable in a first direction to control fluid flow out of the control chamber through the control port and in a second direction to control fluid flow into the control chamber through the control port, means for biasing the main valve spool toward the pilot valve spool, and a force module disposed to selectively exert an increasing control force against the pilot valve spool to move the pilot valve spool in the first direction and a decreasing control force against the pilot valve spool to move the pilot valve spool in the second direction comprising; a compression force feedback spring disposed within the control chamber between the pilot valve spool and the main valve spool; a spring retainer disposed between the feedback spring and the pilot valve spool and having a cylindrical pocket facing the pilot valve spool; and an arcuate convex end portion provided on the pilot valve spool and extending into the cylindrical pocket.
Claim 2
Dependent Claim
200 words
A displacement controlled hydraulic proportional valve having a main valve spool, a control chamber disposed at one end of the main valve spool, a control port communicating with the control chamber, a pilot valve spool in axial alignment with the main valve spool and movable in a first direction to control fluid flow out of the control chamber through the control port and in a second direction to control fluid flow into the control chamber through the control port, means for biasing the main valve spool toward the pilot valve spool, and a force module disposed to selectively exert an increasing control force against the pilot valve spool to move the pilot valve spool in the first direction and a decreasing control force against the pilot valve spool to move the pilot valve spool in the second direction comprising; a compression force feedback spring disposed within the control chamber between the pilot valve spool and the main valve spool; a spring retainer disposed between the feedback spring and the pilot valve spool and having a cylindrical pocket facing the pilot valve spool; and an arcuate convex end portion provided on the pilot valve spool and extending into the cylindrical pocket.
Claim 3
Dependent Claim
40 words
The proportional valve of claim 1 including means defining a cylindrical bore, the spring retainer having an annular flange cooperating with the cylindrical bore to define an annular flow control dampening orifice communicating the control port with the control chamber.
Claim 4
Dependent Claim
28 words
The proportional valve of claim 2 including a stabilizing spring disposed between the body and the pilot valve spool biasing the pilot valve spool in the second direction.
Claim 5
Dependent Claim
18 words
The proportional valve of claim 3 including another stabilizing spring disposed between the body and the spring retainer.
Claim 6
Dependent Claim
28 words
The proportional valve of claim 1 including a stabilizing spring disposed between the body and the pilot valve spool biasing the pilot valve spool in the second direction.
Claim 7
Dependent Claim
18 words
The proportional valve of claim 5 including another stabilizing spring disposed between the body and the spring retainer.
Claim 8
Dependent Claim
17 words
The proportional valve of claim 1 wherein the arcuate convex end portion is a spherical end portion.
References Cited (Backward Citations)
US4201116A
Cited
US5144983A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-09-26 | 1998-03-28 | 1998-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-26 | 2002-03-28 | 2002-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-26 | 2006-03-28 | 2006-09-27 | $7700.00 | Window Closed / Lapsed |