Patent US3882679A successfully refreshed from Google Patents.
US3882679A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control for dual path hydrostatic drive
Assignee: Doosan Bobcat North America Inc
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Filing: 1974-02-28
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Granted: 1975-05-13
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Expires: 1994-02-28
Abstract
Abstract A control for a hydrostatic drive system which has two variable displacement swash plate type pumps connected individually in circuit with two motors. A single vertically disposed control lever is pivotable about a horizontally disposed axis and also is pivotable about its own vertically disposed axis. A transverse portion is rigidly secured to the control lever and extends outwardly from it. A pair of operating rods are connected between the transverse portion and the swash plates of the pumps respectively. A pair of hydraulic power assist devices are mechanically connected to the swash plates respectively. Each of the power assist devices has hydraulic connections to the inlet and outlet of its respective pump which is additive to the force applied by the respective operating rod.
Inventors
- 👤 William Aplin Williamson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:28
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/42; F16H61/437; B; B62; B62D; B62D11/00; B62D11/02; B62D11/06; B62D11/10; B62D11/14; B62D11/18; B62D11/183; Y; Y10; Y10T; Y10T74/00; Y10T74/20; Y10T74/20012
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
152 words
A control mechanism for a dual path hydrostatic drive system having two variable displacement swash plate type pumps connected individually in circuit with two motors, comprising a single vertically disposed control lever pivotable about a horizontally disposed axis and about a vertically disposed axis, a transverse portion rigidly secured to the said control lever and extending outwardly relative to the said vertically disposed axis, a pair of operating rods connected between the said transverse portion and the swash plates of the respective pumps, and a pair of hydraulic power assist devices mechanically connected respectively to the swash plates, each of said devices having hydraulic connections to the pressure and suction chambers of its respective pump and arranged to apply a force to the swash plate of its respective pump which is additive to the force applied by the respective operating rod when the swash plate is in other than its neutral condition.
Claim 2
Dependent Claim
152 words
A control mechanism for a dual path hydrostatic drive system having two variable displacement swash plate type pumps connected individually in circuit with two motors, comprising a single vertically disposed control lever pivotable about a horizontally disposed axis and about a vertically disposed axis, a transverse portion rigidly secured to the said control lever and extending outwardly relative to the said vertically disposed axis, a pair of operating rods connected between the said transverse portion and the swash plates of the respective pumps, and a pair of hydraulic power assist devices mechanically connected respectively to the swash plates, each of said devices having hydraulic connections to the pressure and suction chambers of its respective pump and arranged to apply a force to the swash plate of its respective pump which is additive to the force applied by the respective operating rod when the swash plate is in other than its neutral condition.
Claim 3
Dependent Claim
39 words
A control mechanism as in claim 1 in which the said vertically disposed control lever is selectively pivotable about the said horizontally disposed axis only or about the said vertically disposed axis only or about both said axes simultaneously.
Claim 4
Dependent Claim
39 words
A control mechanism as in claim 1 in which the said transversely disposed portion is at the bottom of the said control lever and the said connections of the operating rods are on opposite sides of the control lever.
Claim 5
Dependent Claim
30 words
A control mechanism as in claim 1 in which the said control lever is rectilinear and the said vertically disposed axis coincides with the longitudinal axis of the control lever.
Claim 6
Dependent Claim
61 words
A control mechanism as in claim 1 in which the total of the forces applied to a pump swash plate by its said operating rod and its respective power assist device, when such swash plate is in other than its neutral condition, is less than the internal force in the pump tending to restore the swash plate to its neutral condition.
Claim 7
Dependent Claim
28 words
A control mechanism as in claim 1 in which each of the said hydraulic power assist devices comprises an outer cylinder and an inner rod axially reciprocal therein.
Claim 8
Dependent Claim
23 words
A control mechanism as in claim 6 in which each of the said rods is pivotally connected to its respective pump swash plate.
Claim 9
Dependent Claim
43 words
A control mechanism as in claim 6 in which the said cylinder includes an inner enlarged diameter portion, and the said rod includes a land portion thereon which cooperates with the said enlarged diameter portion to form a pair of variable volume chambers.
Claim 10
Dependent Claim
32 words
A control mechanism as in claim 8 in which the said variable volume chambers in each power assist device are connected respectively to the pressure and suction chambers of its respective pump.
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) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |