US3613503A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic cylinder with pressure control
Assignee: Eaton Corp
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Filing: 1969-04-28
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Granted: 1971-10-19
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Expires: 1989-04-28
Abstract
Abstract A pressure-actuated control valve which is responsive to an increase in pressure in the contracting or discharge chamber of a hydraulic actuator to restrict discharge flow from said chamber thereby reducing the velocity of the movable barrier therein. The operation of the valve is conditional on inlet pressure as it is held in a nonrestricting position by pressure fluid being admitted to the intake or expanding chamber and moves to a flowrestricting position only when a predetermined loss of pressure occurs in the intake chamber. An additional valve may be included in the system which places the actuator discharge and intake supply passages in communication to shunt fluid therebetween when discharge chamber pressure increases to a predetermined value.
Inventors
- 👤 John F Phillips
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 01:40
CPC Classifications
F; F15; F15B; F15B15/00; F15B15/20; F15B15/22; F15B15/222; F15B13/00; F15B13/01
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
334 words
In a hydraulic actuator including a cylinder defining a working chamber and having an end wall, a piston and rod reciprocable in said chamber and dividing it into a first variable volume chamber in the rod end of the cylinder and a second variable volume chamber adjacent the end wall, a first passage in said end wall connected to said first chamber which serves as an inlet for hydraulic pressure fluid when said first chamber is expanding in volume, a second passage in said end wall connected to said second chamber and which serves as a discharge passage when said second chamber is contracting in volume, a piston velocity control which comprises: a transverse passage in the cylinder end wall communicating with said first and second passages and intersecting said second passage to define a flow restriction in the path of flow through said second passage; a duct communicating said second chamber with said transverse passage; valve means slidable in said transverse passage having one end exposed to the reduced pressure in the discharge passage at the discharge side of the flow restriction and the other end subject to chamber pressure existing in said duct; said valve means having an open position which allows unobstructed flow through said second passage and a closed position which restricts flow through said second passage; valve-controlling means including reciprocable plunger means in said transverse passage which bias said valve means in said normally open position, said valve-controlling means being held in a biasing position by a predetermined inlet pressure in said first passage whereby a loss in inlet pressure to a predetermined level attendant excessive piston velocity allows the valve means to override said bias to move to a closed position and restrict flow through said discharge chamber while permitting unrestricted flow through said discharge chamber while permitting unrestricted flow through said first passage; and said valve-controlling means including a spring exerting a force to assist in holding said valve spool in a normally open unobstructing flow position.
Claim 2
Dependent Claim
334 words
In a hydraulic actuator including a cylinder defining a working chamber and having an end wall, a piston and rod reciprocable in said chamber and dividing it into a first variable volume chamber in the rod end of the cylinder and a second variable volume chamber adjacent the end wall, a first passage in said end wall connected to said first chamber which serves as an inlet for hydraulic pressure fluid when said first chamber is expanding in volume, a second passage in said end wall connected to said second chamber and which serves as a discharge passage when said second chamber is contracting in volume, a piston velocity control which comprises: a transverse passage in the cylinder end wall communicating with said first and second passages and intersecting said second passage to define a flow restriction in the path of flow through said second passage; a duct communicating said second chamber with said transverse passage; valve means slidable in said transverse passage having one end exposed to the reduced pressure in the discharge passage at the discharge side of the flow restriction and the other end subject to chamber pressure existing in said duct; said valve means having an open position which allows unobstructed flow through said second passage and a closed position which restricts flow through said second passage; valve-controlling means including reciprocable plunger means in said transverse passage which bias said valve means in said normally open position, said valve-controlling means being held in a biasing position by a predetermined inlet pressure in said first passage whereby a loss in inlet pressure to a predetermined level attendant excessive piston velocity allows the valve means to override said bias to move to a closed position and restrict flow through said discharge chamber while permitting unrestricted flow through said discharge chamber while permitting unrestricted flow through said first passage; and said valve-controlling means including a spring exerting a force to assist in holding said valve spool in a normally open unobstructing flow position.
Claim 3
Dependent Claim
54 words
The apparatus of claim 1 provided with means movable by and with the piston which cooperate with said second passage to additionally and progressively further restrict the flow of fluid from the cylinder outward through said second passage to decelerate and cushion the stop of said piston as the piston approaches said end wall.
Claim 4
Dependent Claim
51 words
The apparatus described in claim 1 further provided with a bypassage in the cylinder end wall communicating at one end with said second passage and at the other with said second chamber and having a check valve associated therewith to permit flow only from said second passage into the second chamber.
Claim 5
Dependent Claim
103 words
The apparatus of claim 1 wherein said cylinder is further provided with a second transverse passage communicating with said first and second passages, a cannelured valve spool slidably disposed in said second transverse passage, said spool in a first position blocking flow between said first and second passages aNd in a second position establishing communication between said first and second passages, said spool being normally biased to said first position and being pressure responsive to a predetermined pressure in said second chamber to overcome said bias to move to said second flow position and permitting flow through said first passage in both positions.
Claim 6
Dependent Claim
33 words
The apparatus of claim 1 wherein said valve means is provided with metering orifices which permit a predetermined discharge flow through said second passage when said valve means is in a closed position.
Claim 7
Dependent Claim
271 words
A hydraulic system comprising: a first and second hydraulic cylinder each having an end wall; a piston and rod reciprocable in each cylinder dividing each into a first variable volume chamber in the cylinder rod end and a second variable volume chamber adjacent said end wall; each cylinder including a first inlet-discharge passage in direct communication with said first cylinder chamber, a second inlet-discharge passage in communication with said second chamber, and a third recirculation passage in said end wall in communication with said second chamber; a source of fluid pressure having a low-pressure supply reservoir connected to a control valve; conduit means interconnecting said first and third passages of said first cylinder with the third and first passages of said second cylinder respectively; said second inlet-discharge passages of said first and second cylinders being selectively connectable to said pressure source and reservoir through said control valve for tandem operation whereby one piston rod is extending while the other is retracting; a transverse passage in each cylinder end wall communicating with said first, second, and third passages; valve means slidably positioned in said transverse passages, said valve means having a first nonobstructing position and second position effective to restrict discharge flow through said second inlet-discharge passage of the retracting cylinder, said valve means being normally biased to said first position by pressure fluid in said first passage in said retracting cylinder, and being pressure responsive whereby a predetermined reduction in pressure in the retracting cylinder chamber allows said valve means to overcome the bias to move into said second position to restrict discharge flow thereby controlling the velocity of the pistons.
Claim 8
Dependent Claim
271 words
A hydraulic system comprising: a first and second hydraulic cylinder each having an end wall; a piston and rod reciprocable in each cylinder dividing each into a first variable volume chamber in the cylinder rod end and a second variable volume chamber adjacent said end wall; each cylinder including a first inlet-discharge passage in direct communication with said first cylinder chamber, a second inlet-discharge passage in communication with said second chamber, and a third recirculation passage in said end wall in communication with said second chamber; a source of fluid pressure having a low-pressure supply reservoir connected to a control valve; conduit means interconnecting said first and third passages of said first cylinder with the third and first passages of said second cylinder respectively; said second inlet-discharge passages of said first and second cylinders being selectively connectable to said pressure source and reservoir through said control valve for tandem operation whereby one piston rod is extending while the other is retracting; a transverse passage in each cylinder end wall communicating with said first, second, and third passages; valve means slidably positioned in said transverse passages, said valve means having a first nonobstructing position and second position effective to restrict discharge flow through said second inlet-discharge passage of the retracting cylinder, said valve means being normally biased to said first position by pressure fluid in said first passage in said retracting cylinder, and being pressure responsive whereby a predetermined reduction in pressure in the retracting cylinder chamber allows said valve means to overcome the bias to move into said second position to restrict discharge flow thereby controlling the velocity of the pistons.
Claim 9
Dependent Claim
236 words
A hydraulic system comprising: a first and second hydraulic cylinder each having an end wall; a piston and rod reciprocable in each cylinder dividing each into a first variable volume chamber in the rod end and a second variable volume chamber adjacent said end wall; each cylinder including a first inlet discharge passage in direct communication with said first cylinder chamber, a second inlet-discharge passage in communication with said second chamber, and a third recirculation passage in said end wall in communication with said second chamber; means interconnecting said first, second, and third passages of said first and second cylinder for tandem operation whereby one piston rod is extending while the other is retracting, said means interconnecting the expanding cylinder chambers to a common supply of pressure fluid and the contracting chamber to a common discharge; a transverse passage in the cylinder end walls communicating with said first, second, and third passages; pressure responsive valve means slidable in said transverse passages having a first nonobstructing position and a second position effective to restrict discharge flow through said second passage, said valve means operative in the retracting cylinder and being normally biased to said first position by pressure fluid in said first passage in the retracting cylinder and being pressure responsive whereby a predetermined reduction in pressure in said retracting cylinder first passage allows said valve means to overcome the bias to move into said second position.
Claim 10
Dependent Claim
236 words
A hydraulic system comprising: a first and second hydraulic cylinder each having an end wall; a piston and rod reciprocable in each cylinder dividing each into a first variable volume chamber in the rod end and a second variable volume chamber adjacent said end wall; each cylinder including a first inlet discharge passage in direct communication with said first cylinder chamber, a second inlet-discharge passage in communication with said second chamber, and a third recirculation passage in said end wall in communication with said second chamber; means interconnecting said first, second, and third passages of said first and second cylinder for tandem operation whereby one piston rod is extending while the other is retracting, said means interconnecting the expanding cylinder chambers to a common supply of pressure fluid and the contracting chamber to a common discharge; a transverse passage in the cylinder end walls communicating with said first, second, and third passages; pressure responsive valve means slidable in said transverse passages having a first nonobstructing position and a second position effective to restrict discharge flow through said second passage, said valve means operative in the retracting cylinder and being normally biased to said first position by pressure fluid in said first passage in the retracting cylinder and being pressure responsive whereby a predetermined reduction in pressure in said retracting cylinder first passage allows said valve means to overcome the bias to move into said second position.
Claim 11
Dependent Claim
60 words
The apparatus of claim 7 provided witH means movable by and with the piston of said first and second cylinder which cooperate with said second passages in said cylinders as said pistons retract to additionally and progressively further restrict the flow of fluid from the cylinders outward through said second passages to decelerate and cushion the stop of said pistons.
Claim 12
Dependent Claim
47 words
The apparatus of claim 7 wherein each of said cylinders is further provided with a bypassage in the cylinder end wall communicating at one end with said second passage and having a check valve associated therewith to permit flow only from said second passage into the cylinder.
Claim 13
Dependent Claim
103 words
The apparatus of claim 7 wherein each of said cylinders is further provided with a second transverse passage communicating with said first and second passages, a cannelured valve spool slidable disposed in said second transverse passage, said spool in a first position blocking flow between said first and second passages and in a second position establishing communication between said first and second passages, said spool being normally biased to said first position and being pressure responsive to a predetermined second chamber pressure to overcome the bias to move to said second flow position and permitting flow through said first passage in both positions.
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) | 1974-10-18 | 1975-04-19 | 1975-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-18 | 1979-04-19 | 1979-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-18 | 1983-04-19 | 1983-10-19 | $7700.00 | Window Closed / Lapsed |