US3774707A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulically powered drive & steering system for track type vehicle
Assignee: Caterpillar Inc
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Filing: 1971-12-27
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Granted: 1973-11-27
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Expires: 1991-12-27
Abstract
Abstract A hydraulic circuit to provide power and steering functions for a track type vehicle wherein a pair of reversible fluid motors coupled to the track assemblies are individually driven by a separate fluid pump and the speed and direction of the motors is controlled by a pilot operated system. Control of the pilot system is accomplished by two interconnected pilot control circuits including a first pilot circuit for controlling the speed and direction of both motors and a second pilot control circuit for selectively individually controlling the speed and direction of the fluid motors to provide steering functions for the vehicle.
Inventors
- 👤 J Bridwell
- 👤 K Lohbauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:37
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/02; F15B13/04; F15B13/0401; F15B13/0402; B; B62; B62D; B62D11/00; B62D11/02; B62D11/06; B62D11/10; B62D11/14; B62D11/18; B62D11/183; F15B11/00; F15B11/16; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/4061; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/20546; F15B2211/30; F15B2211/32; F15B2211/329; F15B2211/50; F15B2211/52; F15B2211/521; F15B2211/575; F15B2211/60; F15B2211/635; F15B2211/6355; F15B2211/70; F15B2211/705; F15B2211/7058; F15B2211/71
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
167 words
A hydraulic system for controlling a pair of reversible hydraulic motors operatively connected to power a vehicle comprising: a source of pressurized fluid for driving a pair of hydraulic motors; main fluid directing means operatively connected to selectively direct pressurized fluid from said source to said motors for forward or reverse drive thereof; first pilot control means including a source of pilot fluid operatively connected to control said main fluid directing means which is operative to control the flow of fluid to and from said motors and is thus operative for simultaneously controlling the speed and direction of said driven motors; and, second pilot means operatively connected intermediately of said first pilot control means and said main fluid directing means effective upon selective manipulation to alter said control between said first pilot control means and said main fluid directing means to control said fluid directing means and thereby control the fluid flow to said motors to control the speed of a selected one of said driven motors.
Claim 2
Dependent Claim
167 words
A hydraulic system for controlling a pair of reversible hydraulic motors operatively connected to power a vehicle comprising: a source of pressurized fluid for driving a pair of hydraulic motors; main fluid directing means operatively connected to selectively direct pressurized fluid from said source to said motors for forward or reverse drive thereof; first pilot control means including a source of pilot fluid operatively connected to control said main fluid directing means which is operative to control the flow of fluid to and from said motors and is thus operative for simultaneously controlling the speed and direction of said driven motors; and, second pilot means operatively connected intermediately of said first pilot control means and said main fluid directing means effective upon selective manipulation to alter said control between said first pilot control means and said main fluid directing means to control said fluid directing means and thereby control the fluid flow to said motors to control the speed of a selected one of said driven motors.
Claim 3
Dependent Claim
47 words
The hydraulic system of claim 1 wherein said first pilot control means comprises first and second directional pilot valves hydraulically connected between said source of pilot fluid and said main directing means for selectively controlling fluid flow from said pilot fluid source to said main directing means.
Claim 4
Dependent Claim
61 words
The hydraulic system of claim 2 wherein said main fluid directing means comprises first and second variable position pilot actuated fluid control spool valves which are both simultaneously actuated into a fluid directing position by actuation of either one of said first and second directional pilot spool valves for directing fluid from said first Fluid supply source to said driven motors.
Claim 5
Dependent Claim
129 words
The hydraulic system of claim 5 wherein said first fluid supply source comprises a pair of fluid pumps hydraulically connected to said main fluid directing means such that one of said pair of pumps connects to said first variable position pilot actuated fluid control spool valve, the other of said pair of pumps connects to said second variable position pilot actuated fluid control spool valve so that actuation of said first variable position pilot actuated fluid control spool valve directs fluid from said one of said pair of pumps to one of said pair of driven motors, and actuation of said second variable position pilot actuated fluid control spool valve directs fluid from said other of said pair of pumps to the other of said pair of driven motors.
Claim 6
Dependent Claim
38 words
The hydraulic system of claim 1 wherein said second pilot control means comprises first and second steering pilot spool valves, and a single control lever operatively connected to independently actuate both of said first and second steering valves.
Claim 7
Dependent Claim
162 words
A hydraulically powered drive and steering system for a track type vehicle in which a pair of machine supporting track assemblies are individually powered by separate reversible fluid motors comprising: a pair of reversible hydraulic motors; a pair of power supply pumps each separately connected to drive one of said motors; a pilot fluid supply pump; a power circuit including a pair of fluid directing control valves operative to selectively direct fluid to said motors for forward or reverse drive thereof; a pilot control circuit operatively connected for directing pilot fluid from said pilot pump to actuate said fluid directing control valves to a fluid directing position; and, a steering control means operatively connected in said pilot control circuit for selectively altering pilot control pressure in said pilot control circuit to a selected one of said fluid directing control valves to thereby shift said valve independent of the other of said fluid directing control valves to effect steering of the drive system.
Claim 8
Dependent Claim
162 words
A hydraulically powered drive and steering system for a track type vehicle in which a pair of machine supporting track assemblies are individually powered by separate reversible fluid motors comprising: a pair of reversible hydraulic motors; a pair of power supply pumps each separately connected to drive one of said motors; a pilot fluid supply pump; a power circuit including a pair of fluid directing control valves operative to selectively direct fluid to said motors for forward or reverse drive thereof; a pilot control circuit operatively connected for directing pilot fluid from said pilot pump to actuate said fluid directing control valves to a fluid directing position; and, a steering control means operatively connected in said pilot control circuit for selectively altering pilot control pressure in said pilot control circuit to a selected one of said fluid directing control valves to thereby shift said valve independent of the other of said fluid directing control valves to effect steering of the drive system.
Claim 9
Dependent Claim
54 words
The drive and steering system of claim 6 wherein said pilot control circuit includes a pair of manually operable directional pilot control valves operatively connected to that actuation of either of said directional pilot valves actuates both of said air of fluid directing control valves to effect simultaneous forward or reverse of said motors.
Claim 10
Dependent Claim
52 words
The drive and steering system of claim 7 wherein said steering control means includes a pair of manually operable steering pilot valves, reciprocally mounted in separate bores in a single valve housing, and a single control lever mounted on said housing and operative for selectively activating either of said steering pilot valves.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |