US3812925A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrostatic transmission control system
Assignee: Eaton Corp
•
Filing: 1973-03-01
•
Granted: 1974-05-28
•
Expires: 1993-03-01
Abstract
Abstract An improved straight tracking control system equalizes the output speeds of a pair of hydrostatic transmissions during straight forward movement of a vehicle. The control system includes a pump assembly having a housing which is rotated at a speed which varies as a function of variations in the speed of one of the tracks of the vehicle. This housing defines a pumping chamber in which a rotor is rotated at a speed which varies as a function of variations in the speed of the other track of the vehicle. When the vehicle is moving straight forward and the two tracks are being driven at the same speed, there is no relative rotation between the rotor and housing so that the pump assembly is ineffective to pump fluid. Upon acceleration of one of the tracks relative to the other and a resulting relative rotation between the housing and rotor, the pump assembly is effective to discharge fluid under pressure to a piston and cylinder assembly. This fluid actuates the piston and cylinder assembly to operate a valve. Operation of the valve ports fluid to an actuator assembly to vary the output speed of one of the hydrostatic transmissions in a manner so as to equalize the output speeds of the two hydrostatic transmissions. In one embodiment of the invention, a second piston and cylinder assembly is actuated to vary the output speed of a second hydrostatic transmission after the first piston and cylinder assembly has been actuated to vary the output speed of the first hydrostatic transmission.
Inventors
- 👤 C Cargo
- 👤 R Lauck
- 👤 L Meyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:21
CPC Classifications
B; B62; B62D; B62D11/00; B62D11/02; B62D11/06; B62D11/10; B62D11/14; B62D11/18; B62D11/183
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
196 words
A hydrostatic transmission control system for use in association with a vehicle having first and second tracks driven by first and second hydrostatic transmissions, said hydrostatic transmission control system comprising pump means for providing an output signal which varies as a function of variations in the speed at which the tracks are driven relative to each other, said pump means including a rotor associated with the first track and a rotatable housing at least partially enclosing said rotor and associated with the second track, said rotor and housing including means for providing a fluid output signal upon relative rotation between said rotor and housing, first drive means for rotating said rotor at a speed which varies as a function of variations in the speed at which the first track is driven, second drive means for rotating said housing at a speed which varies as a function of variations in the speed at which the second track is driven, and control means connected with said pump means for varying the speed at which at least one of the hydrostatic transmissions drives at least one of the tracks in response to an output signal from said pump means.
Claim 2
Dependent Claim
196 words
A hydrostatic transmission control system for use in association with a vehicle having first and second tracks driven by first and second hydrostatic transmissions, said hydrostatic transmission control system comprising pump means for providing an output signal which varies as a function of variations in the speed at which the tracks are driven relative to each other, said pump means including a rotor associated with the first track and a rotatable housing at least partially enclosing said rotor and associated with the second track, said rotor and housing including means for providing a fluid output signal upon relative rotation between said rotor and housing, first drive means for rotating said rotor at a speed which varies as a function of variations in the speed at which the first track is driven, second drive means for rotating said housing at a speed which varies as a function of variations in the speed at which the second track is driven, and control means connected with said pump means for varying the speed at which at least one of the hydrostatic transmissions drives at least one of the tracks in response to an output signal from said pump means.
Claim 3
Dependent Claim
114 words
A hydrostatic transmission control system as set forth in claim 1 wherein said output signal from said pump means has a fluid pressure characteristic which increases as the difference between the speed at which the first and second tracks are driven increases, said control means including first means for varying the speed at which one of said hydrostatic transmission drives one of said tracks in response to variation of said fluid pressure characteristic within a first range of pressures and second means for varying the speed at which the other one of said hydrostatic transmissions drives the other track in response to variation of said fluid pressure characteristic within a second range of pressures.
Claim 4
Dependent Claim
67 words
A hydrostatic transmission control system as set forth in claim 1 wherein said control means includes means for increasing the output speed of one of the hydrostatic transmissions in response to relative rotation between said rotor and housing in a first direction and for decreasing the output speed of said one hydrostatic transmission in response to relative rotation between said rotor and housing in a second direction.
Claim 5
Dependent Claim
58 words
A hydrostatic transmission control system as set forth in claim 1 wherein said housing includes first surface means for defining a pumping chamber, said rotor being disposed in said pumping chamber and having second surface means for cooperating with said first surface means to pump fluid from said pumping chamber upon relative rotation between said rotor and housing.
Claim 6
Dependent Claim
79 words
A hydrostatic transmission control system as set forth in claim 4 further including a first conduit means connected in fluid communication with said pumping chamber for conducting fluid at a first pressure to said pumping chamber upon relative rotation between said rotor and housing in a first direction and for conducting fluid from said pumping chamber at a second pressure which is greater than said first pressure upon relative rotation between said rotor and housing in a second direction.
Claim 7
Dependent Claim
78 words
A hydrostatic transmission control system as set forth in claim 5 further including second conduit means connected in fluid communication with said pumping chamber for conducting fluid at a third pressure to said pumping chamber upon relative rotation between said rotor and housing in said second direction and for conducting fluid from said pumping chamber at a fourth pressure which is greater than said third pressure upon relative rotation between said rotor and housing in said first direction.
Claim 8
Dependent Claim
32 words
A hydrostatic transmission control system as set forth in claim 6 Further including valve means for blocking fluid flow through at least one of said conduit means upon turning of the vehicle.
Claim 9
Dependent Claim
101 words
A hydrostatic transmission control system as set forth in claim 6 wherein said control means includes piston and cylinder means connected in fluid communication with said first and second conduit means, said piston and cylinder means being operable in one direction from an initial position under the influence of fluid at said second pressure upon relative rotation between said rotor and housing in said second direction, said piston and cylinder means being operable in another direction from the initial position under the influence of fluid at said fourth pressure upon relative rotation between said rotor and housing in said first direction.
Claim 10
Dependent Claim
196 words
A hydrostatic transmission control system as set forth in claim 8 wherein said control means further includes actuator means operable in one direction to increase the output speed of said one of said hydrostatic transmissions and in another direction to decrease the output speed of said one of said hydrostatic transmissions and valve means connected in fluid communication with said actuator means, said valve means being operable from a first condition to a second condition to port fluid under pressure to effect operation of said actuator means to increase the output speed of said one hydrostatic transmission and being operable from said first condition to a third condition to port fluid under pressure to effect operation of said actuator means to decrease the output speed of said one hydrostatic transmission, said piston and cylinder means being connected with said valve means to effect operation of said valve means to the second condition upon operation of said piston and cylinder means in said one direction from said initial position and to effect operation of said valve means to the third condition upon operation of said piston and cylinder means in said other direction from said initial position.
Claim 11
Dependent Claim
67 words
A hydrostatic transmission control system as set forth in claim 6 wherein said control means includes first piston and cylinder means connected in fluid communication with said first fluid conduit means for varying the output speed of said first hydrostatic transmission and second piston and cylinder means connected in fluid eommunication with said second fluid conduit means for varying the output speed of said second hydrostatic transmission.
Claim 12
Dependent Claim
57 words
A hydrostatic transmission control system as set forth in claim 10 further including biasing means connected with at least one of said piston and cylinder means for moving said one of said piston and cylinder means from an operated condition toward an initial condition upon a reduction in the fluid pressure in one of said conduit means.
Claim 13
Dependent Claim
62 words
A hydrostatic transmission control system as set forth in claim 1 further including conduit means for connecting said pump means in fluid communication with said control means, said pump means being operable to communicate to said conduit means a fluid output signal having a pressure characteristic which varies as a function of the speed of relative rotation between said rotor and housing.
Claim 14
Dependent Claim
76 words
A hydrostatic transmission control system as set forth in claim 1 further including conduit means for connecting said pump means in fluid communication with said control means and a source of fluid, and check valve means for enabling fluid to flow from said source of fluid to said pump means through said conduit means and for blocking fluid flow from said pump means to said source of fluid during relative rotation between said rotor and housing.
Claim 15
Dependent Claim
259 words
A hydrostatic transmission control system as set forth in claim 13 wherein said conduit means includes first conduit means for conducting fluid from said source of fluid to said pump means during relative rotation between said rotor and housing in a first direction and for conducting fluid from said pump means to said control means during relative rotation between said rotor and housing in a second direction and second conduit means for conducting fluid from said source of fluid to said pump means during relative rotation between said rotor and housing in the second direction and for conducting fluid from said pump means to said control means during relative rotation between said rotor and housing in the first direction, said valve means including first valve means for enabling fluid to flow through said first conduit means from said source of fluid to said pump means during relative rotation between said rotor and housing in the first direction and for blocking fluid flow through said first conduit means from said pump means to said source of fluid during relative rotation between said rotor and housing in the second direction and second valve means for enabling fluid to flow through said second conduit means from the source of fluid to said pump means during relative rotation between said rotor and housing in the second direction and for blocking fluid flow through said second conduit means from said second conduit means from said pump means to said source of fluid during relative rotation between said rotor and housing in the first direction.
Claim 16
Dependent Claim
193 words
A hydrostatic transmission control system for use in association with first and second members driven by first and second hydrostatic transmissions, said hydrostatic transmission control system comprising pump means for providing an output signal which varies as a function of variations in the speed at which the members are driven relative to each other, said pump means including a rotor associated with the first member and a rotatable housing at least partially enclosing said rotor and associated with the second member, said rotor and housing including means for providing a fluid output signal upon relative rotation between said rotor and housing, first drive means for rotating said rotor at a speed which varies as a function of variations in the speed at which the first member is driven, second drive means for rotating said housing at a speed which varies as a function of variations in the speed at which the second member is driven, and control means connected with said pump means for varying the speed at which at least one of the hydrostatic transmissions drives at least one of the members in response to an output signal from said pump means.
Claim 17
Dependent Claim
193 words
A hydrostatic transmission control system for use in association with first and second members driven by first and second hydrostatic transmissions, said hydrostatic transmission control system comprising pump means for providing an output signal which varies as a function of variations in the speed at which the members are driven relative to each other, said pump means including a rotor associated with the first member and a rotatable housing at least partially enclosing said rotor and associated with the second member, said rotor and housing including means for providing a fluid output signal upon relative rotation between said rotor and housing, first drive means for rotating said rotor at a speed which varies as a function of variations in the speed at which the first member is driven, second drive means for rotating said housing at a speed which varies as a function of variations in the speed at which the second member is driven, and control means connected with said pump means for varying the speed at which at least one of the hydrostatic transmissions drives at least one of the members in response to an output signal from said pump means.
Claim 18
Dependent Claim
114 words
A hydrostatic transmission control system as set forth in claim 15 wherein said output signal from said pump means has a fluid pressure characteristic which increases as the difference between the speed at which the first and second members are driven increases, said control means including first means for varying the speed at which one of said hydrostatic transmissions drives one of said members in response to variation of said fluid pressure characteristic within a first range of pressures and second means for varying the speed at which the other one of said hydrostatic transmissions drives the other member in response to variation of said fluid pressure characteristic within a second range of pressures.
Claim 19
Dependent Claim
67 words
A hydrostatic transmission control system as set forth in claim 15 wherein said control means includes means for increasing the output speed of one of the hydrostatic transmissions in response to relative rotation between said rotor and housing in a first direction and for decreasing the output speed of said one hydrostatic transmission in response to relative rotation between said rotor and housing in a second direction.
Claim 20
Dependent Claim
58 words
A hydrostatic transmission control system as set forth in claim 15 wherein said housing includes first surface means for defining a pumping chamber, said rotor being disposed in said pumping chamber and having second surface means for cooperating with said first surface means to pump fluid from said pumping chamber upon relative rotation between said rotor and housing.
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) | 1977-05-27 | 1977-11-26 | 1978-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-27 | 1981-11-26 | 1982-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-27 | 1985-11-26 | 1986-05-28 | $7700.00 | Window Closed / Lapsed |