US3817033A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic lifting apparatus with constant pull regulation
Assignee: Bosch Rexroth AG
•
Filing: 1972-09-15
•
Granted: 1974-06-18
•
Expires: 1992-09-15
Abstract
Abstract In order to exert a constant pull on a rope attached to a load and wound up on a winch by the motor of a hydrostatic transmission mounted on a floating boat moving up and down, a pressure responsive valve is actuated by a predetermined high pressure in the hydrostatic transmission when the boat and winch are raised, and relieves the pressure in a cylinder chamber of an hydraulic adjusting motor so that the volume of fluid displaced by the pump of the transmission is reduced, whereby the lifting movement is slowed down, and the pull on the rope maintained constant when the boat with the winch is raised by waves to a higher level.
Inventors
- 👤 W Appel
- 👤 R Kordak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:30
CPC Classifications
B; B66; B66D; B66D1/00; B66D1/28; B66D1/40; B66D1/48; B66D1/50; Y; Y10; Y10S; Y10S254/00; Y10S254/90; Y10S60/00; Y10S60/905
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
311 words
Hydraulic lifting apparatus with constant pull regulation, comprising a hydrostatic drive transmission including a driven main pump having adjusting means for regulating the displaced volume, a hydraulic drive motor, and low pressure and high pressure conduits; a hydraulic adjusting motor connected with said adjusting means, and including a cylinder, and a piston in said cylinder forming first and second chambers; a source of pressure fluid; pump conduit means connecting said source with said first chamber; control conduit means between said source and said second chamber; control valve means in said control conduit means having a first control position for connecting said source with said second chamber, and a second control position connecting said second chamber with a low pressure discharge region so that said adjusting motor is operated in said first and second control positions, respectively, to adjust said adjusting means to cause increase and reduction, respectively, of the volume displaced by said main pump, and rotation of said drive motor for lifting and lowering a load; and pressure responsive valve means in said control conduit means having a normal position permitting flow through said control conduit means, and an actuated position connecting said second chamber with said low pressure discharge region, said high pressure conduit of said transmission being connected with said pressure responsive valve means for shifting the same to said actuated position when a predetermined pressure is reached in said high pressure conduit so that the pressure in said second chamber is reduced and the pressure in said first chamber operates said adjusting motor to adjust said adjusting means to reduce the volume displaced by said main pump and thereby the speed of said hydraulic drive motor, and so that when said predetermined pressure is exceeded while said main pump is adjusted by said adjusting motor to idle, the direction of rotation of said drive motor is reversed.
Claim 2
Dependent Claim
311 words
Hydraulic lifting apparatus with constant pull regulation, comprising a hydrostatic drive transmission including a driven main pump having adjusting means for regulating the displaced volume, a hydraulic drive motor, and low pressure and high pressure conduits; a hydraulic adjusting motor connected with said adjusting means, and including a cylinder, and a piston in said cylinder forming first and second chambers; a source of pressure fluid; pump conduit means connecting said source with said first chamber; control conduit means between said source and said second chamber; control valve means in said control conduit means having a first control position for connecting said source with said second chamber, and a second control position connecting said second chamber with a low pressure discharge region so that said adjusting motor is operated in said first and second control positions, respectively, to adjust said adjusting means to cause increase and reduction, respectively, of the volume displaced by said main pump, and rotation of said drive motor for lifting and lowering a load; and pressure responsive valve means in said control conduit means having a normal position permitting flow through said control conduit means, and an actuated position connecting said second chamber with said low pressure discharge region, said high pressure conduit of said transmission being connected with said pressure responsive valve means for shifting the same to said actuated position when a predetermined pressure is reached in said high pressure conduit so that the pressure in said second chamber is reduced and the pressure in said first chamber operates said adjusting motor to adjust said adjusting means to reduce the volume displaced by said main pump and thereby the speed of said hydraulic drive motor, and so that when said predetermined pressure is exceeded while said main pump is adjusted by said adjusting motor to idle, the direction of rotation of said drive motor is reversed.
Claim 3
Dependent Claim
20 words
Apparatus as claimed in claim 1 wherein said first chamber has a smaller effective pressure surface than said second chamber.
Claim 4
Dependent Claim
31 words
Apparatus as claimed in claim 1 wherein said pressure responsive valve means interrupts in said actuated position the flow in said control conduit means from said source to said second chamber.
Claim 5
Dependent Claim
24 words
Apparatus as claimed in claim 1 wherein said control valve means has a position of rest interrupting the flow in said control conduit means.
Claim 6
Dependent Claim
31 words
Apparatus as claimed in claim 1 wherein said control valve means includes a control valve slide piston, and hydraulic shifting means for shifting said control valve slide between said control positions.
Claim 7
Dependent Claim
19 words
Apparatus as claimed in claim 5 comprising resetting means connecting said adjusting means with said control valve slide piston.
Claim 8
Dependent Claim
53 words
Apparatus as claimed in claim 1 wherein said piston of said adjusting motor includes a piston rod projecting through said first chamber out of said cylinder and being connected with said adjusting means so that the effective pressure surface of said piston is smaller in said first chamber than in said second chamber.
Claim 9
Dependent Claim
68 words
Apparatus as claimed in claim 7 comprising resetting means including a pivotally mounted lever connected with said piston rod and with said adjusting means, and resilient means hAving constant resiliency characteristics and connecting said control valve means with said lever; and wherein said control valve means includes a valve slide piston movable between said control positions, and a link connecting said valve slide piston with said resilient means.
Claim 10
Dependent Claim
86 words
Apparatus as claimed in claim 1 wherein said pressure responsive valve means include first and second pressure responsive valves forming conduit portions in said control conduit means connected in series in said normal position; comprising selector valve means for individually connecting said pressure responsive valves with said high pressure conduit; and wherein said pressure responsive valves are responsive to different predetermined high pressures in said high pressure conduit of said transmission to move to actuated positions connecting said second chamber with said low pressure discharge region.
Claim 11
Dependent Claim
39 words
Apparatus as claimed in claim 9 wherein each of said selector valve means includes a selector valve having an open position and a closed position, and an electromagnetic means for shifting the respective selector valve between said positions thereof.
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) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |