Patent US3584712A successfully refreshed from Google Patents.
US3584712A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telescopic hydraulic shock absorbers
Assignee: Armstrong Patents Co Ltd
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Filing: 1969-05-13
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Granted: 1971-06-15
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Expires: 1989-05-13
Abstract
Abstract The invention is an improvement in vehicle telescopic shock absorbers of the type in which a piston carried on a piston rod extending from one end of a pressure tube is slidably displaceable within said pressure tube and the latter is arranged coaxially within an outer reservoir tube with which it cooperates to define an annular space constituting a reservoir for hydraulic fluid, and in which simple closure valves arranged in the piston and between the tube ends remote from the piston rod, control the flow of hydraulic fluid between the pressure tube and the reservoir. The invention provides that these closure valves are arranged respectively to prevent fluid flow through the pistons during extension strokes of the shock absorber and to prevent fluid flow from the pressure tube space in front of the piston to the reservoir during the compression strokes; that the flow of fluid from the pressure tube space behind the piston to the reservoir is confined to a single path which has a single hydraulic damping valve interposed therein to restrict the flow of fluid therethrough; and that the ratio of the cross-sectional areas of the piston and piston rod being selected to produce a predetermined differential between volumes of fluid within the pressure tube displaced by identical piston movements in the two opposed directions and thereby to establish a predetermined differential between the hydraulic damping rates in the two directions.
Inventors
- 👤 Ronald S Dickinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:39
CPC Classifications
F; F16; F16F; F16F9/00; F16F9/32; F16F9/50; F16F9/516
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
407 words
In a vehicle telescopic shock absorber of the type including a pressure tube, a piston slidable in said pressure tube, a reservoir means associated with said pressure tube for supplying hydraulic fluid thereto, first check valve means between said reservoir and pressure tube on one side of said piston for permitting hydraulic flow frOm said reservoir to said pressure tube during an extension stroke of the piston relative to the pressure tube and preventing flow from the pressure tube on one side of said piston to said reservoir during a compression stroke of said piston relative to the pressure tube, second check valve means on said piston means for preventing fluid flow between said one side of said piston means and the other side thereof during the extension stroke and permitting flow from said one side of said piston means to the said other side during the compression stroke; the improvement comprising in combination a first safety check valve means associated with said first check valve means normally closing communication between the pressure tube on said one side of said piston and the reservoir during normal operation of the piston but opening communication between said pressure tube and said reservoir when the pressure in the pressure tube on said one side of said piston exceeds a predetermined amount, a second safety check valve means associated with said second check valve means normally closing communication between opposite sides of said piston during normal operation of said piston in said pressure tube but opening communication between said opposite sides of said piston when the pressure in the pressure tube on said other side of said piston exceeds a predetermined amount, passage means between the reservoir and the pressure tube on said other side of said piston, confining the flow of hydraulic fluid between the pressure tube on said other side of said piston and said reservoir to a single path, and an adjustable damping valve control means located in said passage means for restricting the flow of hydraulic fluid therein to said other side of the piston thereby damping piston movement in both directions in the pressure tube, the ratio between the effective cross-sectional areas on opposite sides of said piston being chosen to establish a predetermined differential between the volumes of hydraulic fluid displaced by identical piston movements in opposite directions to establish a predetermined differential between hydraulic damping rates when the piston moves in said opposite directions.
Claim 2
Dependent Claim
407 words
In a vehicle telescopic shock absorber of the type including a pressure tube, a piston slidable in said pressure tube, a reservoir means associated with said pressure tube for supplying hydraulic fluid thereto, first check valve means between said reservoir and pressure tube on one side of said piston for permitting hydraulic flow frOm said reservoir to said pressure tube during an extension stroke of the piston relative to the pressure tube and preventing flow from the pressure tube on one side of said piston to said reservoir during a compression stroke of said piston relative to the pressure tube, second check valve means on said piston means for preventing fluid flow between said one side of said piston means and the other side thereof during the extension stroke and permitting flow from said one side of said piston means to the said other side during the compression stroke; the improvement comprising in combination a first safety check valve means associated with said first check valve means normally closing communication between the pressure tube on said one side of said piston and the reservoir during normal operation of the piston but opening communication between said pressure tube and said reservoir when the pressure in the pressure tube on said one side of said piston exceeds a predetermined amount, a second safety check valve means associated with said second check valve means normally closing communication between opposite sides of said piston during normal operation of said piston in said pressure tube but opening communication between said opposite sides of said piston when the pressure in the pressure tube on said other side of said piston exceeds a predetermined amount, passage means between the reservoir and the pressure tube on said other side of said piston, confining the flow of hydraulic fluid between the pressure tube on said other side of said piston and said reservoir to a single path, and an adjustable damping valve control means located in said passage means for restricting the flow of hydraulic fluid therein to said other side of the piston thereby damping piston movement in both directions in the pressure tube, the ratio between the effective cross-sectional areas on opposite sides of said piston being chosen to establish a predetermined differential between the volumes of hydraulic fluid displaced by identical piston movements in opposite directions to establish a predetermined differential between hydraulic damping rates when the piston moves in said opposite directions.
Claim 3
Dependent Claim
43 words
The combination defined in claim 1 wherein said valve control means includes a rotatable valve member having a plurality of circumferentially distributed ports of different cross-sectional areas to be placed in selective communication with said passage means upon rotation of said valve member.
Claim 4
Dependent Claim
45 words
The combination defined in claim 1 wherein said valve control means including means defining a port surrounded by a valve seat, and a conical valve head movable towards and away from said seat for selectively varying the area between the valve head and the seat.
Claim 5
Dependent Claim
36 words
The combination defined in claim 1 further including an additional safety valve means arranged in said passage means and acting to assist said control valve means in regulating the fluid pressure generated during the compression stroke.
Claim 6
Dependent Claim
58 words
The combination defined in claim 1 wherein said reservoir surrounds said pressure tube, and includes a bleed tube having one end in communication with said pressure tube on said other side of said piston, the other end of said bleed tube communicating with said adjustable control valve means, said bleed tube constituting a part of said passage means.
Claim 7
Dependent Claim
55 words
The combination defined in claim 5 wherein said control valve means includes a housing mounted in a sidewall portion of said reservoir, said housing having a flow passage receiving said other end of said bleed tube, and a movable valve member mounted in said housing for controlling flow between the reservoir and said bleed tube.
Claim 8
Dependent Claim
45 words
The combination defined in claim 6 wherein said passage means includes a passage formed in one end of said pressure tube communicating with said one end of said bleed tube and the interior of the pressure tube on said other side of said piston means.
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) | 1974-06-14 | 1974-12-14 | 1975-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-14 | 1978-12-14 | 1979-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-14 | 1982-12-14 | 1983-06-15 | $7700.00 | Window Closed / Lapsed |