Patent US3716308A successfully refreshed from Google Patents.
US3716308A
Expired / Lapsed
US
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Hydraulic system
Assignee: Robert Bosch GmbH
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Filing: 1971-01-26
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Granted: 1973-02-13
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Expires: 1991-01-26
Abstract
Abstract The user circuit for a pump having an output greater than the maximum output that can be accepted by the prime mover for the pump has a relief valve for shunting hydraulic fluid from the user circuit when the pressure within the circuit demands an output from the pump that exceeds the output available from the prime mover. The delivery side of the pump is connected to a piston that acts on the relief valve to open the latter in response to pressure within the user circuit.
Inventors
- 👤 W Kobald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:46
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/4148; F15; F15B; F15B11/00; F15B11/16; F15B11/17; F16H61/4008; F16H61/4017; F16H61/4043; F16H61/44; F16H61/448; F16H61/46; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/20538; F15B2211/20576; F15B2211/50; F15B2211/505; F15B2211/50509; F15B2211/50536; F15B2211/515; F15B2211/5157; F15B2211/55
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
227 words
A hydraulic circuit comprising, in combination, a first and a second pump with constant volume delivery; driving means for operating said first and said second pump, the maximum output of said driving means being less than the maximum output that can be delivered by said first and said second pump; a user circuit connected to the delivery side of each of said pumps for accepting the hydraulic fluid delivered by said first and said second pumps, respectively; relief valve means for the user circuit of at least one of said pumps and including resilient means for holding said relief valve means in closed position until the pressure in said user circuit of said at least one of said pumps exceeds a predetermined required pressure and pressure responsive means acting on said relief valve means in opposition to the resilient means of the latter and being connected to the delivery side of both said first and said second pumps and responsive to the pressure thereat to reduce, with increasing pressure at said delivery side, the said predetermined required pressure to open the relief valve means under the influence of the fluid pressure in said user circuit of said at least one of said pumps so that the relief valve means opens to thereby reduce the pressure in the last mentioned user circuit before said driving means can stall.
Claim 2
Dependent Claim
227 words
A hydraulic circuit comprising, in combination, a first and a second pump with constant volume delivery; driving means for operating said first and said second pump, the maximum output of said driving means being less than the maximum output that can be delivered by said first and said second pump; a user circuit connected to the delivery side of each of said pumps for accepting the hydraulic fluid delivered by said first and said second pumps, respectively; relief valve means for the user circuit of at least one of said pumps and including resilient means for holding said relief valve means in closed position until the pressure in said user circuit of said at least one of said pumps exceeds a predetermined required pressure and pressure responsive means acting on said relief valve means in opposition to the resilient means of the latter and being connected to the delivery side of both said first and said second pumps and responsive to the pressure thereat to reduce, with increasing pressure at said delivery side, the said predetermined required pressure to open the relief valve means under the influence of the fluid pressure in said user circuit of said at least one of said pumps so that the relief valve means opens to thereby reduce the pressure in the last mentioned user circuit before said driving means can stall.
Claim 3
Dependent Claim
227 words
A hydraulic circuit comprising, in combination, a first and a second pump with constant volume delivery; driving means for operating said first and said second pump, the maximum output of said driving means being less than the maximum output that can be delivered by said first and said second pump; a user circuit connected to the delivery side of each of said pumps for accepting the hydraulic fluid delivered by said first and said second pumps, respectively; relief valve means for the user circuit of at least one of said pumps and including resilient means for holding said relief valve means in closed position until the pressure in said user circuit of said at least one of said pumps exceeds a predetermined required pressure and pressure responsive means acting on said relief valve means in opposition to the resilient means of the latter and being connected to the delivery side of both said first and said second pumps and responsive to the pressure thereat to reduce, with increasing pressure at said delivery side, the said predetermined required pressure to open the relief valve means under the influence of the fluid pressure in said user circuit of said at least one of said pumps so that the relief valve means opens to thereby reduce the pressure in the last mentioned user circuit before said driving means can stall.
Claim 4
Dependent Claim
227 words
A hydraulic circuit comprising, in combination, a first and a second pump with constant volume delivery; driving means for operating said first and said second pump, the maximum output of said driving means being less than the maximum output that can be delivered by said first and said second pump; a user circuit connected to the delivery side of each of said pumps for accepting the hydraulic fluid delivered by said first and said second pumps, respectively; relief valve means for the user circuit of at least one of said pumps and including resilient means for holding said relief valve means in closed position until the pressure in said user circuit of said at least one of said pumps exceeds a predetermined required pressure and pressure responsive means acting on said relief valve means in opposition to the resilient means of the latter and being connected to the delivery side of both said first and said second pumps and responsive to the pressure thereat to reduce, with increasing pressure at said delivery side, the said predetermined required pressure to open the relief valve means under the influence of the fluid pressure in said user circuit of said at least one of said pumps so that the relief valve means opens to thereby reduce the pressure in the last mentioned user circuit before said driving means can stall.
Claim 5
Dependent Claim
37 words
An hydraulic system as defined in claim 12, wherein said pressure responsive means is a piston acting on said relief valve means to open the latter with increasing pressure at said delivery side of said one pump.
Claim 6
Dependent Claim
50 words
An hydraulic system as defined in claim 2, including resilient means acting on said relief valve means to open the latter, said piston acting on said resilient means to increase the pressure of the latter on said relief valve with increasing pressure at said delivery side of said one pump.
Claim 7
Dependent Claim
98 words
An hydraulic system as defined in claim 1, including pressure regulating valve means connected to the delivery side of said relief valve means; hydraulic fluid line means connected between said pressure regulating valve means and said relief valve means; vessel means at atmospheric pressure; and pressure responsive valve means connected to said hydraulic fluid line means and connecting said user circuit of said one pump to said vessel means, said pressure responsive valve means opening in response to increasing pressure in said hydraulic fluid line means to permit discharge from said user circuit means into said vessel means.
Claim 8
Dependent Claim
41 words
An hydraulic system as defined in claim 1, said pressure responsive means having a discrete pressure bearing surface for each of said first and second pumps, each said surface bearing only the pressure at said delivery side of the associated pump.
Claim 9
Dependent Claim
17 words
An hydraulic system as defined in claim 5, wherein said pressure responsive means is a differential piston.
References Cited (Backward Citations)
US2273152A
Cited
US3601506A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-13 | 1976-08-14 | 1977-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-13 | 1980-08-14 | 1981-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-13 | 1984-08-14 | 1985-02-13 | $7700.00 | Window Closed / Lapsed |