US3568856A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic cushioning device for railway cars
Assignee: Pullman Standard Inc
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Filing: 1969-07-22
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Granted: 1971-03-09
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Expires: 1989-07-22
Abstract
Abstract A double-acting hydraulic cushioning device for railway cars is formed with a hydraulic fluid filled cylinder having a closed end and an open end through which a piston rod is movable for reciprocating a piston within the cylinder. A flexible accumulator boot is connected to the piston rod and to an intermediate cylinder head for closing the end of the cylinder. A metering pin cooperates with the piston for providing a relatively constant metered flow from the cylinder to the accumulator during the buff stroke on the unit. The piston is provided with a sliding valve and orifice plate which cooperates with the metering pin to meter the flow during the buff stroke and to move to another position during the return stroke thereby permitting an increased flow of fluid from the accumulator boot through the cylinder. The intermediate cylinder head is provided with a cavity which contains a fluid pressure responsive valve slidable to open passages leading from the accumulator boot to the cylinder and in a return and draft stroke of the piston the valve being movable over the passages to restrict the flow therethrough. The valve plate and the piston has a configuration which permits misalignment of the piston relative to the axis of the cylinder without affecting the metering operation. Further, the piston is provided with a piston ring engaging the cylinder wall with the piston ring groove on the piston being designed to permit misalignment without affecting the sealing relation of the piston ring. The slidable valve plate within the recess or cavity of the intermediate cylinder is also of a flexible construction which in the event of misalignment does not impair its functional operation.
Inventors
- 👤 Willis H Knippel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:07
CPC Classifications
B; B61; B61G; B61G9/00; B61G9/04; B61G9/08
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
349 words
A hydraulic cushioning device for railway cars including: a hydraulic cylinder including a first cylinder head adjacent one end thereof, a metering pin supported on said first cylinder head and extending longitudinally within said cylinder, said cylinder being open on an opposite end thereof; said cylinder including a second intermediate cylinder head fixed in said cylinder and being positioned between said open end and said first head to provide a high-pressure chamber, said intermediate head having a longitudinal opening therethrough, a piston positioned for reciprocation within said chamber; metering means on said piston including an annular portion providing a metering opening encircling said metering pin to control the fluid flow through said passageway system; said piston being movable from a neutral position between said cylinder heads to a buff position in proximity to said first heaD, and to a draft position in proximity to said second head; a piston rod connected to said piston and extending through said longitudinal head opening and said open end; a flexible tubular reservoir having one end connected around said piston rod and its other end connected to said intermediate head to provide a second low-pressure chamber; said piston rod and piston including a passageway system communicating said second chamber with said first chamber; said intermediate cylinder head including a recessed portion surrounding said piston rod and including passageway means providing for communication with said second chamber and said first chamber, the improvement comprising: a longitudinally slidable valve element in said recessed portion; said valve element having an inner annular portion radially spaced from and encircling said piston rod; said valve element including a ring of flexible material on said inner portion and engaging said piston rod in sliding relation, said valve element on said movement of said piston to a buff position opening said passageway means for the passage of fluid from said second to said first chambers, and on movement of said piston to a draft position, said second valve element restricting fluid flow through said passageway means; and said flexible ring accommodating relative misalignment of said cylinder and piston rod axes.
Claim 2
Dependent Claim
349 words
A hydraulic cushioning device for railway cars including: a hydraulic cylinder including a first cylinder head adjacent one end thereof, a metering pin supported on said first cylinder head and extending longitudinally within said cylinder, said cylinder being open on an opposite end thereof; said cylinder including a second intermediate cylinder head fixed in said cylinder and being positioned between said open end and said first head to provide a high-pressure chamber, said intermediate head having a longitudinal opening therethrough, a piston positioned for reciprocation within said chamber; metering means on said piston including an annular portion providing a metering opening encircling said metering pin to control the fluid flow through said passageway system; said piston being movable from a neutral position between said cylinder heads to a buff position in proximity to said first heaD, and to a draft position in proximity to said second head; a piston rod connected to said piston and extending through said longitudinal head opening and said open end; a flexible tubular reservoir having one end connected around said piston rod and its other end connected to said intermediate head to provide a second low-pressure chamber; said piston rod and piston including a passageway system communicating said second chamber with said first chamber; said intermediate cylinder head including a recessed portion surrounding said piston rod and including passageway means providing for communication with said second chamber and said first chamber, the improvement comprising: a longitudinally slidable valve element in said recessed portion; said valve element having an inner annular portion radially spaced from and encircling said piston rod; said valve element including a ring of flexible material on said inner portion and engaging said piston rod in sliding relation, said valve element on said movement of said piston to a buff position opening said passageway means for the passage of fluid from said second to said first chambers, and on movement of said piston to a draft position, said second valve element restricting fluid flow through said passageway means; and said flexible ring accommodating relative misalignment of said cylinder and piston rod axes.
Claim 3
Dependent Claim
32 words
The invention in accordance with claim 1, said inner peripheral portion of said valve element having an annular undercut, and said flexible ring having an outer diameter portion disposed in said undercut.
Claim 4
Dependent Claim
121 words
The invention in accordance with claim 1, said piston having an annular cavity communicating with said passageway system and said first chamber; a second slidable valve element in said cavity; said second element having an inner annular portion encircling said metering pin; said second element metering the fluid flow to said passageway system during movement to a buff position, and being slidable to another position during movement to a draft position to provide an unrestricted flow of fluid from said passageway system to said second chamber; and said inner annular portion in transverse cross section defining a generally V-shaped configuration providing a reduced annular contact portion with said metering pin to accommodate relative misalignment of said piston rod and cylinder axes.
Claim 5
Dependent Claim
120 words
The invention in accordance with claim 2, piston having an annular cavity communicating with said passageway system and said first chamber; a second slidable valve element in said cavity; said second element having an inner annular portion encircling said metering pin; said second element metering the fluid flow to said passageway system during movement to a buff position, and being slidable to another position during movement to a draft position to provide an unrestricted flow of fluid from said passageway system to said second chamber; and said inner annular portion in transverse cross section defining a generally V-shaped configuration providing a reduced annular contact portion with said metering pin to accommodate relative misalignment of said piston rod and cylinder axes.
Claim 6
Dependent Claim
65 words
The invention in accordance with claim 2, said piston including an outer circumferential surface having a piston ring groove coextensive therewith; said groove including a bottom wall, and laterally spaced upright walls, and a piston ring disposed in said groove; and said bottom wall being of arcuate configuration with opposite side portions of said bottom wall sloping from a central portion downwardly toward said sidewalls.
Claim 7
Dependent Claim
32 words
The invention in accordance with claim 5, said outer circumferential surface being of generally arcuate configuration with opposite side portions thereof sloping inwardly away from an inner cylindrical wall of said cylinder.
Claim 8
Dependent Claim
30 words
The invention in accordance with claim 6, said piston ring having an inner circumferential surface parallel to said inner cylindrical wall engaging said central portion of said arcuate bottom wall.
Claim 9
Dependent Claim
257 words
A hydraulic cushioning device for railway cars including: a hydraulic cylinder including a first cylinder head adjacent one end thereof, said cylinder being open on an opposite end thereof; said cylinder including a second intermediate cylinder head fixed in said cylinder and being positioned between said open end and said first head to provide a high-pressure chamber, said intermediate head having a longitudinal opening therethrough, a piston positioned for reciprocation within said cylinder and defining one end of said chamber; said piston being movable from a neutral position between said cylinder heads to a buff position in proximity to said first head, and to a draft position in proximity to said second head; a piston rod connected to said piston and extending through said longitudinal head opening and said open end; a flexible tubular reservoir having one end connected around said piston rod and its other end connected to said intermediate head to provide a second low-pressure chamber; said piston rod and piston including a passageway system communicating said second chamber with said first chamber; said intermediate cylinder head including a recessed portion surrounding said piston rod and including passageway means providing for communication with said second chamber and said first chamber, the improvement comprising: a longitudinally slidable valve element in said recessed portion; said valve element having an inner annular portion radially spaced from and encircling said piston rod, said annular portion having an undercut groove coextensive therewith, and a ring of flexible material carried in said groove and in sliding engagement with said piston rod.
Claim 10
Dependent Claim
257 words
A hydraulic cushioning device for railway cars including: a hydraulic cylinder including a first cylinder head adjacent one end thereof, said cylinder being open on an opposite end thereof; said cylinder including a second intermediate cylinder head fixed in said cylinder and being positioned between said open end and said first head to provide a high-pressure chamber, said intermediate head having a longitudinal opening therethrough, a piston positioned for reciprocation within said cylinder and defining one end of said chamber; said piston being movable from a neutral position between said cylinder heads to a buff position in proximity to said first head, and to a draft position in proximity to said second head; a piston rod connected to said piston and extending through said longitudinal head opening and said open end; a flexible tubular reservoir having one end connected around said piston rod and its other end connected to said intermediate head to provide a second low-pressure chamber; said piston rod and piston including a passageway system communicating said second chamber with said first chamber; said intermediate cylinder head including a recessed portion surrounding said piston rod and including passageway means providing for communication with said second chamber and said first chamber, the improvement comprising: a longitudinally slidable valve element in said recessed portion; said valve element having an inner annular portion radially spaced from and encircling said piston rod, said annular portion having an undercut groove coextensive therewith, and a ring of flexible material carried in said groove and in sliding engagement with said piston rod.
Claim 11
Dependent Claim
56 words
The invention in accordance with claim 8, said piston having an outer circumferential surface of semispherical shape, a piston ring groove in said surface, said groove having a bottom wall of semispherical configuration, and a piston ring disposed in said piston ring groove and projecting outwardly therefrom for engaging the inner cylindrical wall of said cylinder.
Claim 12
Dependent Claim
52 words
The invention in accordance with claim 8, said piston having an outer semispherical portion; a ring-shaped element having an inner circumferential surface conforming to said semispherical portion and axially tiltably disposed thereon; and said ring-shaped element having an outer circumferential surface including a piston ring engaging the inner wall of said cylinder.
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) | 1974-03-08 | 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 |