US4066279A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pneumatic spring of adjustable length
Assignee: Stabilus GmbH
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Filing: 1976-03-23
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Granted: 1978-01-03
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Expires: 1996-03-23
Abstract
Abstract The piston rod of a pneumatic spring is expelled from the cylinder by compressed fluid in the cylinder until a normally open channel connecting two compartments of the cylinder cavity on opposite axial sides of the piston is blocked by cooperating valve elements on the cylinder and on the piston assembly.
Inventors
- 👤 Panoyotis Kaptanis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:39
CPC Classifications
F; F16; F16F; F16F9/00; F16F9/32; F16F9/56; E; E05; E05F; E05F3/00; E05F3/02; F16F9/02; F16F9/0209; F16F9/0245; F16F9/34; F16F9/346; E05Y; E05Y2800/00; E05Y2900/00; E05Y2900/20; E05Y2900/50; E05Y2900/53; E05Y2900/536
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
184 words
A pneumatic spring comprising: a. a cylinder having an axis and bounding a sealed cavity therein; b. a piston assembly including 1. a piston portion movable in said cavity between two axially terminal positions and separating two compartments of said cavity, and 2. an axially elongated piston rod portion having one axially terminal part fastened to said piston portion in said cavity and another axially terminal part outside said cavity, said piston rod portion movably passing through said cylinder; c. a body of fluid in said cavity under a pressure higher than atmospheric pressure and permanently biasing said piston rod portion outward of said cavity; d. conduit means bounding a channel connecting said compartments for flow of said fluid between said compartments; and e. cooperating valve means on said cylinder and on said piston assembly responsive to movement of said piston portion into a position spacedly intermediate said terminal positions for closing said channel and for thereby sealing said compartments from each other, and responsive to movement of said piston portion from said intermediate position toward either terminal position thereof for opening said channel.
Claim 2
Dependent Claim
184 words
A pneumatic spring comprising: a. a cylinder having an axis and bounding a sealed cavity therein; b. a piston assembly including 1. a piston portion movable in said cavity between two axially terminal positions and separating two compartments of said cavity, and 2. an axially elongated piston rod portion having one axially terminal part fastened to said piston portion in said cavity and another axially terminal part outside said cavity, said piston rod portion movably passing through said cylinder; c. a body of fluid in said cavity under a pressure higher than atmospheric pressure and permanently biasing said piston rod portion outward of said cavity; d. conduit means bounding a channel connecting said compartments for flow of said fluid between said compartments; and e. cooperating valve means on said cylinder and on said piston assembly responsive to movement of said piston portion into a position spacedly intermediate said terminal positions for closing said channel and for thereby sealing said compartments from each other, and responsive to movement of said piston portion from said intermediate position toward either terminal position thereof for opening said channel.
Claim 3
Dependent Claim
44 words
A spring as set forth in claim 1, wherein said cylinder has an inner face bounding said cavity and formed with an axially elongated groove therein, said face constituting a portion of said conduit means, and said groove constituting a portion of said channel.
Claim 4
Dependent Claim
60 words
A spring as set forth in claim 2, wherein said face has a face portion axially offset from said groove, and said piston assembly has an annular face extending about said axis and shaped for sealing engagement with said face portion in said intermediate position of said piston portion, said face portion and said annular face constituting said valve means.
Claim 5
Dependent Claim
81 words
A spring as set forth in claim 1, wherein said piston assembly is formed with an axial passage constituting a portion of said channel, and said valve means include a rod member axially fastened to said cylinder and partly received in said passage and a valves eat member mounted on said piston assembly in said passage, an axial portion of said rod member being enlarged for sealing engagement with said valve seat member in said intermediate position of said piston portion.
Claim 6
Dependent Claim
43 words
A spring as set forth in claim 1, further comprising check valve means operatively interposed between said compartments and responsive to movement of said piston assembly in only one axial direction for connecting said compartments in said intermediate position of said piston portion.
Claim 7
Dependent Claim
41 words
A spring as set forth in claim 5, wherein said check valve means respond to a pressure differential between said compartments generated by external force axially applied to said other part of said piston rod portion and moving said piston assembly.
Claim 8
Dependent Claim
119 words
A spring as set forth in claim 5, wherein said piston portion and said cylinder define therebetween an axial flow path communicating with one of said compartments, and said check valve means include a piston ring mounted on said piston portion for limited axial movement between a first position and a second position in sealing engagement with said cylinder, said piston ring being formed with an axial opening therethrough, said opening communicating with the other one of said compartments in all axial positions of said piston ring, said piston ring in said first position engaging said piston portion and thereby sealing said flow path, said opening communicating with said flow path in said second position of said piston ring.
Claim 9
Dependent Claim
42 words
A pneumatic spring comprising: a. a cylinder having an axis and bounding a cavity therein; b. a piston assembly including 1. a piston portion axially movable in said cavity between two terminal positions and axially separating two compartments of said cavity, and
Claim 10
Dependent Claim
42 words
A pneumatic spring comprising: a. a cylinder having an axis and bounding a cavity therein; b. a piston assembly including 1. a piston portion axially movable in said cavity between two terminal positions and axially separating two compartments of said cavity, and
Claim 11
Dependent Claim
177 words
an axially elongated piston rod portion having one axially terminal part fastened to said piston portion in said cavity and another axially terminal part outside said cavity, said piston rod portion movably passing through said cylinder, said terminal positions of said piston portion being adjacent and remote from said other axially terminal part of said piston rod portion respectively; c. a fluid sealed in said compartments, the pressure of said fluid being higher than atmospheric pressure in all axial positions of said piston portion, whereby said fluid permanently biases said piston rod portion outward of said cavity; d. conduit means bounding a channel connecting said compartments for flow of said fluid between said compartments; and e. cooperating valve means on said cylinder and on said piston assembly responsive to movement of said piston portion into a position spacedly intermediate said terminal positions for closing said channel and for thereby sealing said compartments from each other, and responsive to movement of said piston portion from said intermediate position toward said remote terminal position thereof for opening said channel.
Claim 12
Dependent Claim
177 words
an axially elongated piston rod portion having one axially terminal part fastened to said piston portion in said cavity and another axially terminal part outside said cavity, said piston rod portion movably passing through said cylinder, said terminal positions of said piston portion being adjacent and remote from said other axially terminal part of said piston rod portion respectively; c. a fluid sealed in said compartments, the pressure of said fluid being higher than atmospheric pressure in all axial positions of said piston portion, whereby said fluid permanently biases said piston rod portion outward of said cavity; d. conduit means bounding a channel connecting said compartments for flow of said fluid between said compartments; and e. cooperating valve means on said cylinder and on said piston assembly responsive to movement of said piston portion into a position spacedly intermediate said terminal positions for closing said channel and for thereby sealing said compartments from each other, and responsive to movement of said piston portion from said intermediate position toward said remote terminal position thereof for opening said channel.
Claim 13
Dependent Claim
34 words
A spring as set forth in claim 8, wherein said valve means further respond to movement of said piston portion from said intermediate position toward said adjacent terminal position thereof for opening said channel.
Claim 14
Dependent Claim
20 words
A spring as set forth in claim 9, wherein said fluid includes a body of gas under said higher pressure.
References Cited (Backward Citations)
US1446793A
Cited
US3917245A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-02 | 1981-07-04 | 1982-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-02 | 1985-07-04 | 1986-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-02 | 1989-07-04 | 1990-01-03 | $7700.00 | Window Closed / Lapsed |