Patent US3685290A successfully refreshed from Google Patents.
US3685290A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overload system for a hydrostatic-drive apparatus
Assignee: Linde GmbH
•
Filing: 1971-03-15
•
Granted: 1972-08-22
•
Expires: 1991-03-15
Abstract
Abstract An overload safety system for a hydrostatically driven crane in which a valve assembly applies pilot fluid to a fluid-control main station which, in turn, shifts the hydrostatic drive out of its neutral position corresponding to the displacement of the control valve member. A reversing (changeover) valve connects the lines to opposite sides of the main valve with an electrically operated relief valve, the latter being actuated by an electrical signal on overload to depressurize the pilot line and apply a brake to the power member of the crane.
Inventors
- 👤 Alfred Krusche
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:43
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/4157; F16H61/46; F16H61/478
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
189 words
A hydrostatic drive for a load, comprising: a hydrostatic pump and a hydrostatic motor connected in a power circuit and coupled with said load while being provided with a control member shiftable into and out of a neutral position; a control unit for said power circuit and including a pistonand-cylinder arrangement operatively connected to said member, a distributing valve connected to said piston-and-cylinder arrangement for controlling fluid flow thereto to displace said member, and pressure-transmitting means connected to said distributing valve for applying pressure to opposite sides thereof via respective pilot-fluid lines to operate said valve and effect displacement of said member; a changeover valve having a pair of inlets each connected to a respective one of said lines and a control line relievable to bleed pressure from said pilot-fluid lines; a relief valve communicating with said control line and energizable to relieve the pressure therein; means responsive to the development of an undesired condition concerning said load for energizing said relief valve to bleed the pressurized one of said pilot-fluid lines; and a throttle in each of said pilot-fluid lines between said pressure-transmitting means and said distributing valve.
Claim 2
Dependent Claim
189 words
A hydrostatic drive for a load, comprising: a hydrostatic pump and a hydrostatic motor connected in a power circuit and coupled with said load while being provided with a control member shiftable into and out of a neutral position; a control unit for said power circuit and including a pistonand-cylinder arrangement operatively connected to said member, a distributing valve connected to said piston-and-cylinder arrangement for controlling fluid flow thereto to displace said member, and pressure-transmitting means connected to said distributing valve for applying pressure to opposite sides thereof via respective pilot-fluid lines to operate said valve and effect displacement of said member; a changeover valve having a pair of inlets each connected to a respective one of said lines and a control line relievable to bleed pressure from said pilot-fluid lines; a relief valve communicating with said control line and energizable to relieve the pressure therein; means responsive to the development of an undesired condition concerning said load for energizing said relief valve to bleed the pressurized one of said pilot-fluid lines; and a throttle in each of said pilot-fluid lines between said pressure-transmitting means and said distributing valve.
Claim 3
Dependent Claim
29 words
The hydrostatic drive defined in claim 1 wherein said pressure-transmitting means includes a respective control valve connected between a source of fluid pressure and each of said pilot-fluid lines.
Claim 4
Dependent Claim
17 words
The hydrostatic drive defined in claim 2 wherein said control valves are each of the quick-break type.
Claim 5
Dependent Claim
63 words
The hydrostatic drive defined in claim 1 for a crane having a plurality of such drives each connected to a respective load, further comprising an additional changeover valve having a pair of inlets each connected to the control line of the first-mentioned changeover valve of each of said hydrostatic drives said additional changeover valve having a control line connected to said relief valve.
Claim 6
Dependent Claim
61 words
The hydrostatic drive defined in claim 1 further comprising a brake for locking said load, a cylinder pressurizable to release said brake, and a brake valve responsive to the pressure in said control line for connecting the last-mentioned cylinder with a source of fluid pressure, said brake valve draining said last-mentioned cylinder upon the relief of pressure in said control line.
Claim 7
Dependent Claim
56 words
The hydrostatic drive defined in claim 1 wherein said pressure-transmitting means includes a respective quick-break control valve connected between a source of fluid pressure and each of said pilot-fluid lines, said source being an auxiliary pump, said relief valve being an electromagnetic valve electrically energized by the means responsive to the development of said undesired condition.
Claim 8
Dependent Claim
49 words
The hydrostatic drive defined in claim 1 for a crane having a plurality of such drives each connected to a respective load, one of said drives being an lifting mechanism, said means responsive to the development of an undesired condition being an overload detector connected to said lifting mechanism.
Claim 9
Dependent Claim
60 words
The hydrostatic drive defined in claim 1 for a crane having at least two such drives, said crane having a boom controlled by one of said drives, the control lines of said hydrostatic drives being connected to respective inlets of at least one additional changeover valve, said reLief valve being communicating with the control line of said additional changeover valve.
Claim 10
Dependent Claim
17 words
The hydrostatic drive defined in claim 8, further comprising an internal combustion engine for driving said pumps.
Claim 11
Dependent Claim
152 words
A hydrostatic drive for a load, comprising: a hydrostatic pump and a hydrostatic motor connected in a power circuit and coupled with said load while being provided with a control member shiftable into and out of a neutral position; a control unit for said power circuit and including a piston-and-cylinder arrangement operatively connected to said member, a distributing valve connected to said piston-and-cylinder arrangement for controlling fluid flow thereto to displace said member, and a pilot-fluid line connected to said distributing valve and pressurizable for displacing said member; means for pressurizing said pilot-fluid line; a relief valve communicating with said pilot-fluid line and energizable to relieve the pressure therein; means responsive to the development of an undesired condition for energizing said relief valve to bleed said pilot-fluid line and thereby shift said member into said neutral position; and a throttle in said pilot-fluid line between said energizing means and said relief valve.
Claim 12
Dependent Claim
152 words
A hydrostatic drive for a load, comprising: a hydrostatic pump and a hydrostatic motor connected in a power circuit and coupled with said load while being provided with a control member shiftable into and out of a neutral position; a control unit for said power circuit and including a piston-and-cylinder arrangement operatively connected to said member, a distributing valve connected to said piston-and-cylinder arrangement for controlling fluid flow thereto to displace said member, and a pilot-fluid line connected to said distributing valve and pressurizable for displacing said member; means for pressurizing said pilot-fluid line; a relief valve communicating with said pilot-fluid line and energizable to relieve the pressure therein; means responsive to the development of an undesired condition for energizing said relief valve to bleed said pilot-fluid line and thereby shift said member into said neutral position; and a throttle in said pilot-fluid line between said energizing means and said relief valve.
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) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |