US3584698A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrostatic scraper wheel drive
Assignee: Caterpillar Inc
•
Filing: 1968-07-23
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Granted: 1971-06-15
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Expires: 1988-07-23
Abstract
Abstract A hydrostatic assist for driving the normally nondriven wheels of a vehicle in which the hydrostatic assist is controlled by slip in the drive train or the driven wheels for better tractive effort and most efficient operation. The slip sensed for control may be the slip between the normally driven wheels and the ground or the slip in a nonpositive coupling portion of the drive line between the vehicle engine and the driven wheels and controls the power which is supplied to the nondriven wheels through a hydrostatic loop.
Inventors
- 👤 Robert V Larson
- 👤 James E Scheidt
- 👤 Sebald K Stahl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:19
CPC Classifications
B; B60; B60K; B60K17/00; B60K17/04; B60K17/10; B60K17/34; B60K17/356
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
231 words
In an earthmoving vehicle having a tractor unit and a connected articulated trailer unit wherein the tractor unit includes an engine driving its tractor support wheels through a mechanical drive train with a torque converter between said engine and said drive train and wherein the trailer unit includes trailer support wheels which are not coupled to said drive train, an automatic hydrostatic assist system for driving said trailer support wheels comprising: a fixed displacement hydraulic motor means located on said trailer unit; gear means mechanically connecting said motor means with said trailer support wheels whereby torque developed by said motor means can be applied to drive said trailer support wheels; a fixed displacemenT pump means located on said tractor unit; connecting means having conduits coupling said motor means and said pump means in a hydrostatic loop wherein power will be transferred by the circulation of hydraulic fluid within said loop; and means mechanically connecting said pump means with said engine in a ratio wherein said pump means has insufficient fluid output volume through said loop to cause said motor means to drive said trailer support wheels until a predetermined amount of slip has occurred in said torque converter coupling said engine with said drive train whereat the increased relative fluid output of said pump means will transmit power to said trailer support wheels through said hydrostatic loop and said motor means.
Claim 2
Dependent Claim
231 words
In an earthmoving vehicle having a tractor unit and a connected articulated trailer unit wherein the tractor unit includes an engine driving its tractor support wheels through a mechanical drive train with a torque converter between said engine and said drive train and wherein the trailer unit includes trailer support wheels which are not coupled to said drive train, an automatic hydrostatic assist system for driving said trailer support wheels comprising: a fixed displacement hydraulic motor means located on said trailer unit; gear means mechanically connecting said motor means with said trailer support wheels whereby torque developed by said motor means can be applied to drive said trailer support wheels; a fixed displacemenT pump means located on said tractor unit; connecting means having conduits coupling said motor means and said pump means in a hydrostatic loop wherein power will be transferred by the circulation of hydraulic fluid within said loop; and means mechanically connecting said pump means with said engine in a ratio wherein said pump means has insufficient fluid output volume through said loop to cause said motor means to drive said trailer support wheels until a predetermined amount of slip has occurred in said torque converter coupling said engine with said drive train whereat the increased relative fluid output of said pump means will transmit power to said trailer support wheels through said hydrostatic loop and said motor means.
Claim 3
Dependent Claim
52 words
The automatic hydrostatic assist system defined in claim 1 wherein the fixed displacement hydraulic motor means includes a plurality of hydraulic motors, one motor associated with each trailer support wheel and the hydrostatic loop includes a flow divider insuring a delivery of equal volume of hydraulic fluid to each of said motors.
Claim 4
Dependent Claim
63 words
The automatic hydrostatic assist system as defined in claim 1 wherein the gear means mechanically connecting the motor means with the trailer support wheels includes a plurality of ratios which can be selected simultaneously with gear ratios in the drive train for maintaining a relative relationship between the drive of the tractor support wheels and the assist drive of the trailer support wheels.
Claim 5
Dependent Claim
17 words
The automatic hydrostatic assist system as defined in claim 1 wherein the vehicle is an earthmoving scraper.
Claim 6
Dependent Claim
48 words
The automatic hydrostatic assist system as defined in claim 1 wherein the increased relative fluid output of the pump means includes drive means which will cause it to begin to transmit power through the hydrostatic loop and motor means when the slip in torque converter approaches 10 percent.
References Cited (Backward Citations)
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Cited
US2913061A
Cited
US3227235A
Cited
US3293942A
Cited
US3339660A
Cited
US3354978A
Cited
US3480099A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-14 | 1974-12-14 | 1975-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-14 | 1978-12-14 | 1979-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-14 | 1982-12-14 | 1983-06-15 | $7700.00 | Window Closed / Lapsed |