Patent US3593977A successfully refreshed from Google Patents.
US3593977A
Expired / Lapsed
US
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Self-leveling hydropneumatic shock absorber
Assignee: ThyssenKrupp Bilstein GmbH
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Filing: 1969-02-24
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Granted: 1971-07-20
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Expires: 1989-02-24
Abstract
Abstract Shock absorber with a dashpot assembly whose piston (3) carries two axially spaced heads (4, 18) cooperating with an interposed annular partition (24) on the inner wall of its cylinder (2) and with the two cylinder end walls (5, 9) to form four chambers of variable volume, i.e. a first damping chamber (22) partly filled with air and communicating with a surrounding oil reservoir (11), a pumping chamber (23) connected with an inlet (10) from the oil reservoir containing a check valve, an intermediate chamber (29) receiving oil from the pumping chamber through one-way orifices (26) of the partition (24), and a second damping chamber (16) receiving oil from the intermediate chamber through one-way passages (31) in the adjoining piston head (4) while also communicating with a fluid space (15) under pressure from a surrounding air cushion (13), the latter chamber having an exit to the pumping chamber blocked by a regulating valve (38) in a contracted position of the assembly. In an extended position, in which a tube (34) rigid with the cylinder (2) opens the regulating valve (38), the pumping chamber (23) is in two-way communication with the reservoir (11) through an opening (20) unblocked by the other piston head (18). an extended position, in which a tube (34) rigid with the cylqnder (''2) opens the regulating valve (38), the pumping chamb r (23) is in two-way communication wilh the reservoir (11): THROUGH -N OPENING (20) unblocked by t8e other piston head (18'').
Inventors
- 👤 Erich Hahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:58
CPC Classifications
B; B60; B60G; B60G17/00; B60G17/02; B60G17/04; B60G17/044
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
258 words
A shock absorber comprising: a generally cylindrical housing; a dashpot assembly in said housing including a cylinder rigid with said housing and a piston axially displaceable in said cylinder, said piston having a pair of axially spaced heads, said cylinder having a first end penetrated by said piston, a second end sealed by a transverse wall and an inner annular partition slidably bearing upon said piston at a location between said piston heads, one of said piston heads proximal to said first end defining with said partition an annular pumping chamber of variable volume, the other of said piston heads defining with said partition an annular intermediate chamber of variable volume and with said transverse wall a damping chamber of variable volume; a reservoir of hydraulic liquid; first unidirectionally effective valve means forming a one-way inlet from said reservoir to said pumping chamber, sAid partition and said other of said piston heads having passages provided with second and third unidirectionally effective valve means, respectively, for letting hydraulic liquid travel from said pumping chamber by way of said intermediate chamber to said damping chamber upon relative reciprocation of said piston and said cylinder in any relative position thereof; conduit means forming a return path for excess liquid from said damping chamber to said reservoir; flow-blocking means in said return path effective in a relatively contracted position of said dashpot assembly; release means effective in a relatively extended position of said dashpot assembly for deactivating said flow-blocking means; and pressure-accumulating means for said hydraulic liquid communicating with said damping chamber.
Claim 2
Dependent Claim
258 words
A shock absorber comprising: a generally cylindrical housing; a dashpot assembly in said housing including a cylinder rigid with said housing and a piston axially displaceable in said cylinder, said piston having a pair of axially spaced heads, said cylinder having a first end penetrated by said piston, a second end sealed by a transverse wall and an inner annular partition slidably bearing upon said piston at a location between said piston heads, one of said piston heads proximal to said first end defining with said partition an annular pumping chamber of variable volume, the other of said piston heads defining with said partition an annular intermediate chamber of variable volume and with said transverse wall a damping chamber of variable volume; a reservoir of hydraulic liquid; first unidirectionally effective valve means forming a one-way inlet from said reservoir to said pumping chamber, sAid partition and said other of said piston heads having passages provided with second and third unidirectionally effective valve means, respectively, for letting hydraulic liquid travel from said pumping chamber by way of said intermediate chamber to said damping chamber upon relative reciprocation of said piston and said cylinder in any relative position thereof; conduit means forming a return path for excess liquid from said damping chamber to said reservoir; flow-blocking means in said return path effective in a relatively contracted position of said dashpot assembly; release means effective in a relatively extended position of said dashpot assembly for deactivating said flow-blocking means; and pressure-accumulating means for said hydraulic liquid communicating with said damping chamber.
Claim 3
Dependent Claim
43 words
A shock absorber as defined in claim 1 wherein said position has a terminal portion with an axially extending bore open toward said damping chamber and forming part of said conduit means, said flow-blocking means including a valve member seated in said bore.
Claim 4
Dependent Claim
32 words
A shock absorber as defined in claim 2 wherein said release means comprises a link extending from said transverse wall into said bore and forming a lost-motion connection with said valve member.
Claim 5
Dependent Claim
64 words
A shock absorber as defined in claim 3 wherein said link is a tube, said valve member being provided with a stem extending into said tube and terminating in a boss within said tube engageable by an inward projection on said tube, said flow-blocking means further including a spring in said tube bearing upon said boss for urging said valve member against a seat.
Claim 6
Dependent Claim
33 words
A shock absorber as defined in claim 2 wherein said path is provided with throttle means beyond said valve member and with a filter screen between said throttle means and said valve member.
Claim 7
Dependent Claim
62 words
A shock absorber as defined in claim 2 wherein said piston is provided with a channel forming part of said conduit means and extending from a point of said bore beyond said valve member to said pumping chamber, said return path further including an outlet from said pumping chamber unblocked by said one of said piston heads in said relatively extended position.
Claim 8
Dependent Claim
57 words
A shock absorber as defined in claim 6 wherein said reservoir is part of a ring space defined by said housing and a portion of said cylinder proximal to said first end thereof, said pressure-accumulator means being disposed in an annular space between said housing and a portion of said cylinder proximal to said second end thereof.
Claim 9
Dependent Claim
20 words
A shock absorber as defined in claim 7 wherein said pressure-accumulating means comprising an air cushion in said annular space.
Claim 10
Dependent Claim
91 words
A shock absorber as defined in claim 7 wherein said housing is provided with an end wall sealing said ring space and forming a damping space within said cylinder between said end wall and said one of said piston heads, said outlet being disposed on said cylinder in the region of said reservoir and opening into the interior of said cylinder at a location within the sweep of said one of said piston heads, said cylinder further having a port beyond said sweep permanently interconnecting said damping space and said reservoir.
Claim 11
Dependent Claim
47 words
A shock absorber as defined in claim 9 wherein said cylinder and piston are upright, said piston projecting from the top of said housing, said damping space and said reservoir containing a confined air volume above the liquid level thereof, said port being located above said level.
References Cited (Backward Citations)
US3147826A
Cited
US3450235A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-19 | 1975-01-18 | 1975-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-19 | 1979-01-18 | 1979-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-19 | 1983-01-18 | 1983-07-20 | $7700.00 | Window Closed / Lapsed |