US3603576A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydropneumatic suspension unit with automatic level regulation
Assignee: ThyssenKrupp Bilstein GmbH
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Filing: 1969-05-27
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Granted: 1971-09-07
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Expires: 1989-05-27
Abstract
Abstract A self-pumping hydropneumatic suspension unit is provided with automatic level regulation operative even when the vehicle is stationary. The suspension-unit housing holds an electric pumpdriving motor and also a regulating valve. A level-control switch electrically controls operation of the motor on the one hand and of the valve on the other hand in dependence on the vehicle load.
Inventors
- 👤 Erich Hahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:35
CPC Classifications
B; B60; B60G; B60G17/00; B60G17/02; B60G17/04; B60G17/044; B60G17/015; B60G17/0152; B60G17/0157; B60G17/019; B60G17/01933; B60G2204/00; B60G2204/10; B60G2204/11; B60G2204/112; B60G2401/00; B60G2401/17; B60G2401/172
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
183 words
A self-regulating hydraulic suspension unit comprising: a casing forming a pressurized reservoir for a working liquid; an upright cylinder in said housing; a working piston in said cylinder defining therein a working chamber and having an outwardly projecting piston rod for elevating a load in response to hydraulic pressure from said chamber; conduit means in said housing forming a first passage and a second passage for said liquid between said reservoir and said chamber; normally inoperative pump means in said first passage; electric drive means supported by said casing for operating said pump means to feed liquid from said reservoir to said chamber; normally closed valve means in said second passage; electric control means for opening said valve means to enable a return flow of liquid from said chamber to said reservoir; and switch means individual to said unit responsive to the relative position of said cylinder and said piston for actuating said drive means to operate said pump means in a relatively low load position and for actuating said control means to open said valve means in a relatively high load position.
Claim 2
Dependent Claim
183 words
A self-regulating hydraulic suspension unit comprising: a casing forming a pressurized reservoir for a working liquid; an upright cylinder in said housing; a working piston in said cylinder defining therein a working chamber and having an outwardly projecting piston rod for elevating a load in response to hydraulic pressure from said chamber; conduit means in said housing forming a first passage and a second passage for said liquid between said reservoir and said chamber; normally inoperative pump means in said first passage; electric drive means supported by said casing for operating said pump means to feed liquid from said reservoir to said chamber; normally closed valve means in said second passage; electric control means for opening said valve means to enable a return flow of liquid from said chamber to said reservoir; and switch means individual to said unit responsive to the relative position of said cylinder and said piston for actuating said drive means to operate said pump means in a relatively low load position and for actuating said control means to open said valve means in a relatively high load position.
Claim 3
Dependent Claim
43 words
The combination defined in claim 1, further including delay means connected with said switch means for preventing actuation of said drive means and said control means in response to short term displacements of said piston and said cylinder from a normal relative position.
Claim 4
Dependent Claim
35 words
The combination defined in claim 2 wherein said drive means and said control means are provided with respective operating circuits controlled by said switch means, said delay means including time-lag relays in said operating circuits.
Claim 5
Dependent Claim
32 words
The combination defined in claim 2 wherein said delay means comprises a dashpot assembly mechanically linked with said piston and said cylinder, said switch means including contacts controlled by said dashpot assembly.
Claim 6
Dependent Claim
42 words
The combination defined in claim 4 wherein said piston rod is hollow and forms a liquid space communicating with said chamber, said dashpot assembly including an ancillary piston in said chamber and a resilient linkage between said ancillary piston and said cylinder.
Claim 7
Dependent Claim
20 words
The combination defined in claim 5 wherein said resilient linkage comprises a compression spring and a tension spring in tandem.
Claim 8
Dependent Claim
27 words
The combination defined in claim 6 wherein said cylinder is internally provided with an axially extending guide element entering said liquid space and serially traversing said springs.
Claim 9
Dependent Claim
15 words
The combination defined in claim 1 wherein said switch means is supported by said casing.
Claim 10
Dependent Claim
45 words
The combination defined in claim 8 wherein said switch means comprises a collapsible structure engaging said piston and said cylinder and contacts on said structure closable upon a predetermined change in size of said structure due to relative motion of said piston and said cylinder.
Claim 11
Dependent Claim
37 words
The combination defined in claim 9 wherein the projecting part of said piston rod is provided with a mounting plate confronting an end of said cylinder, said structure being inserted between said mounting plate and said end.
Claim 12
Dependent Claim
20 words
The combination defined in claim 10 wherein said structure is a bellows having said contacts secured to respective folds thereof.
Claim 13
Dependent Claim
57 words
The combination defined in claim 10 wherein said structure is a flat coil spring and said switch means comprises a switch housing on a turn of said spring and a button on said switch housing bearing upon an adjoining turn of said spring, said contacts being disposed in said housing for opening and closing by said button.
Claim 14
Dependent Claim
45 words
The combination defined in claim 8 wherein said piston is conductive, said switch means comprising two axially separated, mutually insulated conductive portions of said cylinder alternatively engageable by said piston for completing respective circuits for the actuation of said drive means and said control means.
Claim 15
Dependent Claim
38 words
The combination defined in claim 8 wherein said piston rod is hollow, said switch means including contacts in said piston rod and plunger means in said piston rod connected with said cylinder for opening and closing said contacts.
Claim 16
Dependent Claim
56 words
The combination defined in claim 14 wherein said plunger means comprises a rigid element extending axially into said piston rod and a nest of springs of different strength interposed between said element and said contacts for establishing an inactive and two active positions for the latter, said contacts being biased to oppose displacement by said springs.
Claim 17
Dependent Claim
60 words
The combination defined in claim 14 wherein the interior of said piston rod forms a sealed fluid space filled with hydraulic liquid, said switch means including a hydraulically shiftable member in said fluid space cooperating with said contacts and an element rigid with said cylinder extending axially into said fluid space foR exerting a variable hydraulic pressure upon said member.
Claim 18
Dependent Claim
56 words
The combination defined in claim 1 wherein said cylinder has an end closed by a plug with an outer flange portion partitioning said housing into a first compartment including said reservoir and a second compartment isolated therefrom, said pump means being disposed in said plug, said drive means being a motor disposed in said second compartment.
Claim 19
Dependent Claim
41 words
The combination defined in claim 1 wherein said pump means comprises a pair of reciprocating plungers alignedly supported on said casing, said drive means comprising a motor with a cam shaft between said plungers bearing upon confronting extremities of the latter.
Claim 20
Dependent Claim
28 words
The combination defined in claim 18 wherein plungers are substantially parallel to the axis of said cylinder and are mounted laterally on said casing together with said motor.
References Cited (Backward Citations)
US3181877A
Cited
US3222048A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-06 | 1975-03-08 | 1975-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-06 | 1979-03-08 | 1979-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-06 | 1983-03-08 | 1983-09-07 | $7700.00 | Window Closed / Lapsed |