US3568705A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic system circuit breaker
Assignee: Bendix Corp
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Filing: 1969-08-19
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Granted: 1971-03-09
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Expires: 1989-08-19
Abstract
Abstract A hydraulic circuit breaker or fail-safe device is disclosed for sensing leaks in lines to and from hydraulic actuators or the like. Flow through the line is sensed across a restriction on a piston valve member movable to close the line, the size of the restriction being such that flow in excess of normal requirements causes a significantly increased pressure drop, which drop is sensed across a quantity measuring piston movable in a chamber within the piston-valve, and causing the latter piston to move within its chamber at a rate controlled by the area of a control orifice. As this latter piston moves, it carries a shaft which is spring biased to resist movement until the pressure drop across the restriction reaches a value indicative of a leak. Two spool valve members are carried on the shaft whose function in the two embodiments shown is to direct either supply pressure or lower pressure against operating areas of the piston-valve to control its movement to open or close the line. A check valve is placed in a return line and an additional piston in contact with the biasing spring senses a leak in the return line as indicated by a changed pressure drop across the check valve and moves to either remove the effective spring bias on the shaft or to move the shaft directly such that the spool valve members direct flow to cause the piston-valve to close the line.
Inventors
- 👤 George I Boyadjieff
- 👤 Robert K Van Ausdal
- 👤 Ralph L Vick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:17
CPC Classifications
F; F15; F15B; F15B20/00; F15B20/005; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2703; Y10T137/2705; Y10T137/7722; Y10T137/7723; Y10T137/7726; Y10T137/7727
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
344 words
A hydraulic safety device for connection between a source of hydraulic fluid under pressure and a device to be controlled comprising: a housing having an inlet port connected to said source, a high pressure outlet port connected to said supply controlled device, and a return port for receiving return flow from said device; a chamber in said housing connecting said inlet port and said high pressure outlet port; a first piston movable in said chamber between a first position in which flow passes between said inlet port and said high pressure outlet port and a second position where said high pressure outlet port is blocked; said piston including ridge means cooperating with the walls of said chamber to form a restricted passageway, and a second chamber within said piston; resilient means in said housing urging said piston toward said first position; a shaft and a second piston in said second chamber carried on said shaft and first and second passages communicating opposite sides of said second piston with opposite sides of said ridge means; a third piston on said shaft positioned in normal operation to permit communication between the inlet pressure side of said second piston and one end of said first piston, and movable with said second piston to a second position to interrupt said communication and to open communication between said one end of said first piston and a source of hydraulic fluid at return pressure; a fluid chamber adjacent said shaft and an orifice positioned to control the rate of flow out of said chamber and, therefore, the movement of said shaft; whereby when a leak occurs downstream of said high pressure outlet port the resulting fluid pressure differential across said restricted passageway is sensed across said second piston causing said second and third pistons to move against the force of said resilient means and at a rate controlled by said orifice until said third piston reaches its second position, causing said first piston to be moved by the force of inlet pressure from said first position to said second position.
Claim 2
Dependent Claim
344 words
A hydraulic safety device for connection between a source of hydraulic fluid under pressure and a device to be controlled comprising: a housing having an inlet port connected to said source, a high pressure outlet port connected to said supply controlled device, and a return port for receiving return flow from said device; a chamber in said housing connecting said inlet port and said high pressure outlet port; a first piston movable in said chamber between a first position in which flow passes between said inlet port and said high pressure outlet port and a second position where said high pressure outlet port is blocked; said piston including ridge means cooperating with the walls of said chamber to form a restricted passageway, and a second chamber within said piston; resilient means in said housing urging said piston toward said first position; a shaft and a second piston in said second chamber carried on said shaft and first and second passages communicating opposite sides of said second piston with opposite sides of said ridge means; a third piston on said shaft positioned in normal operation to permit communication between the inlet pressure side of said second piston and one end of said first piston, and movable with said second piston to a second position to interrupt said communication and to open communication between said one end of said first piston and a source of hydraulic fluid at return pressure; a fluid chamber adjacent said shaft and an orifice positioned to control the rate of flow out of said chamber and, therefore, the movement of said shaft; whereby when a leak occurs downstream of said high pressure outlet port the resulting fluid pressure differential across said restricted passageway is sensed across said second piston causing said second and third pistons to move against the force of said resilient means and at a rate controlled by said orifice until said third piston reaches its second position, causing said first piston to be moved by the force of inlet pressure from said first position to said second position.
Claim 3
Dependent Claim
135 words
A hydraulic safety device as set forth in claim 1 wherein a check valve is located between said return port and the return side of said source, a fourth piston is positioned coaxially with said shaft and fluid conduits are provided connecting opposite sides of said fourth piston across said check valve, such that upon the occurrence of a substantial loss of pressure upstream of said return port, said check valve will close and said fourth piston will sense the differential across said check valve and will move to compress said spring, moving said shaft until said third piston blocks communication between said inlet port and said one end of said first piston thus releasing the high inlet pressure acting against said one end and causing said first piston to move to said second position.
Claim 4
Independent Claim
255 words
A device for blocking a flow of fluid from a high pressure source to a utilization device in response to excessive flow indicating a leakage comprising: a housing; an inlet conduit connecting said source with said housing; an outlet conduit connecting said housing with said utilization device; a return conduit connecting said utilization device with said housing; first valve means in said housing movable from a First position permitting flow from said inlet conduit to said outlet conduit to a second position in which flow from said inlet conduit to said outlet conduit is blocked, and flow restriction means associated with said first valve means; second valve means including pressure responsive means for sensing the pressure drop across said flow restriction means and flow directing means movable with said pressure responsive means to a first position to connect one side of said first valve means with fluid pressure in said inlet conduit to maintain said first valve means in its said first position or to a second position to direct fluid pressure acting against said one side of said first valve means to said return conduit which permits said first valve means to be moved to said second position; a chamber containing fluid in contact with said second valve means and orifice means restricting flow from said chamber to control the rate of movement of said second valve means; and resilient means urging said second valve means toward a position where inlet conduit pressure is directed against said one side of said first valve means.
Claim 5
Independent Claim
255 words
A device for blocking a flow of fluid from a high pressure source to a utilization device in response to excessive flow indicating a leakage comprising: a housing; an inlet conduit connecting said source with said housing; an outlet conduit connecting said housing with said utilization device; a return conduit connecting said utilization device with said housing; first valve means in said housing movable from a First position permitting flow from said inlet conduit to said outlet conduit to a second position in which flow from said inlet conduit to said outlet conduit is blocked, and flow restriction means associated with said first valve means; second valve means including pressure responsive means for sensing the pressure drop across said flow restriction means and flow directing means movable with said pressure responsive means to a first position to connect one side of said first valve means with fluid pressure in said inlet conduit to maintain said first valve means in its said first position or to a second position to direct fluid pressure acting against said one side of said first valve means to said return conduit which permits said first valve means to be moved to said second position; a chamber containing fluid in contact with said second valve means and orifice means restricting flow from said chamber to control the rate of movement of said second valve means; and resilient means urging said second valve means toward a position where inlet conduit pressure is directed against said one side of said first valve means.
Claim 6
Dependent Claim
107 words
A device for blocking a flow of fluid as set forth in claim 4 including a check valve connected between said return conduit and the return side of said source; pressure responsive means connected across said check valve to sense the pressure drop across said check valve and movable in response to a substantial drop in pressure in said return conduit in a direction to oppose said resilient means, thereby moving said second valve means such that said flow directing means connects said one side of said first valve means with said return conduit, thus causing said first valve means to be moved to its second position.
Claim 7
Dependent Claim
57 words
A device for blocking a flow of fluid as set forth in claim 3 wherein said first valve means includes a piston having said one side, an opposite side and in inner chamber, and said second valve means includes a second piston movable within said inner chamber and communicating with opposite sides of said flow restriction means.
Claim 8
Dependent Claim
109 words
A device for sensing a flow of fluid as set forth in claim 5 wherein said piston is fastened to a shaft movable therewith, said flow directing means constitutes a spool valve member on said shaft, a chamber communicating with the opposite side of said piston is provided containing fluid communicating with said return conduit, and an additional spool valve member is carried on said shaft such that when said second valve means is in its first position, it blocks flow between said outlet conduit and said chamber, and when said second valve means is in its second position it permits flow between said outlet conduit and said chamber.
Claim 9
Dependent Claim
52 words
A device for sensing a flow of fluid as set forth in claim 6 wherein said first valve means encloses said first named chamber which communicates with said return conduit, and a second piston is carried on said shaft and movable within said first named chamber, said piston including said orifice means.
Claim 10
Dependent Claim
82 words
A device for blocking a flow of fluid as set forth in claim 5 wherein said piston is fastened to a shaft movable therewith, said flow directing means constitutes a spool valve member on said shaft, said first named chamber forms part of said inner chamber, a third piston forms one end of said inner chamber, a passageway is provided in said third piston communicating said first named chamber with said return conduit and said orifice means is positioned in said passageway.
Claim 11
Dependent Claim
107 words
A device for blocking a flow of fluid as set forth in claim 8 including a check valve connected between said return conduit and the return side of said source, a fourth piston is connected across said check valve to sense the pressure drop across said check valve and movable in response to a substantial drop in pressure in said return conduit in a direction to oppose said resilient means, thereby moving said second valve means such that said spool valve member connects said one side of said first named piston with said return conduit thus causing said first piston to be moved to its second position.
References Cited (Backward Citations)
US2649773A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |