Patent US3914938A successfully refreshed from Google Patents.
US3914938A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical hydrostatic transmission control system
Assignee: Eaton Corp
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Filing: 1974-08-20
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Granted: 1975-10-28
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Expires: 1994-08-20
Abstract
Abstract An improved apparatus is provided to control the operation of a plurality of hydrostatic transmissions which are advantageously utilized to drive the tracks of a vehicle. This apparatus includes a signal generator which provides an electrical ratio command signal which is variable to correspond to any one of a plurality of displacements and output speeds of a pair of hydrostatic transmissions. Right and left steering command signal generators are selectively operable to provide electrical steering command signals which effect operation of actuator assemblies to vary the output speed of one of the hydrostatic transmissions relative to the other hydrostatic transmission to turn the vehicle. A straight tracking control apparatus includes a pair of speed sensing units which are effective to provide electrical speed signals which vary in value as a function of variations in the output speed of an associated hydrostatic transmission. During movement of the vehicle along a straight path, the electrical speed signals are compared and utilized to effect activation of one or more of the actuator assemblies if the output speed of one of the transmissions is different from the output speed of the other transmission. Upon actuation of the steering controls, the straight tracking apparatus is rendered ineffective so that the vehicle can be turned. Anti-stall circuitry is provided to prevent overloading of the engine.
Inventors
- 👤 Charles R Cornell
- 👤 Gerald F O'callaghan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:37
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/46; F16H61/478; B; B62; B62D; B62D11/00; B62D11/02; B62D11/06; B62D11/10; B62D11/14; B62D11/18; B62D11/183; Y; Y10; Y10S; Y10S60/00; Y10S60/911
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
272 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the ouTput speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, and first secondary command signal generator means for providing a first secondary electrical command signal, said first electrical control means including means for effecting operation of said first actuator means to vary the displacement of at least said one unit of said first hydrostatic transmission to a displacement other than the displacement indicated by said main electrical command signal in response to said first secondary electrical command signal to vary the output speed of said first hydrostatic transmission relative to the output speed of said second hydrostatic transmission.
Claim 2
Independent Claim
272 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the ouTput speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, and first secondary command signal generator means for providing a first secondary electrical command signal, said first electrical control means including means for effecting operation of said first actuator means to vary the displacement of at least said one unit of said first hydrostatic transmission to a displacement other than the displacement indicated by said main electrical command signal in response to said first secondary electrical command signal to vary the output speed of said first hydrostatic transmission relative to the output speed of said second hydrostatic transmission.
Claim 3
Dependent Claim
96 words
An apparatus as set forth in claim 1 further including second secondary command signal generator means for providing a second secondary electrical command signal, said second electrical control means including means for effecting operation of said second actuator means to vary the displacement of at least said one unit of said second hydrostatic transmission to a displacement other than the displacement indicated by said main electrical command signal in response to said secondary electrical command signal to vary the output speed of said second hydrostatic transmission relative to the output speed of said first hydrostatic transmission.
Claim 4
Dependent Claim
324 words
An apparatus as set forth in claim 2 wherein said first actuator means is operable to vary the displacement of said one unit of said first hydrostatic transmission between a forward operating condition in which said first hydrostatic transmission has an output speed in a forward direction and a reverse operating condition in which said first hydrostatic transmission has an output speed in a reverse direction, said second actuator means being operable to vary the displacement of said one unit of said second hydrostatic transmission between a forward operating condition in which said second hydrostatic transmission has an output speed in the forward direction and a reverse operating condition in which said second hydrostatic transmission has an output speed in a reverse direction, said main electrical command signal generator means including means for providing a main command signal having a first characteristic and value to effect operation of said first and second hydrostatic transmissions in the forward direction at a first speed and a second characteristic and value to effect operation of said first and second hydrostatic transmissions in the reverse direction at said first speed, said first secondary command signal generator means including means for providing a secondary electrical command signal of said second characteristic and at least said second value when said main electrical command signal has said first characteristic and value to effect operation of said first hydrostatic transmission in the reverse direction at said first speed during operation of said second hydrostatic transmission in the forward direction at said first speed, said second secondary command signal generator means including means for providing a secondary electrical command signal of said second characteristic and at least said second value when said main electrical command signal has said first characteristic and value to effect operation of said second hydrostatic transmission in the reverse direction at saId first speed during operation of said first hydrostatic transmission in the forward direction at said first speed.
Claim 5
Independent Claim
270 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, and first feedback signal generator means for providing a first electrical feedback signal which is indicative of the displacement of said one unit of said first hydrostatic transmission, said first control means including means for comparing said main electrical command signal and said first electrical feedback signal and for effecting operation of said first actuator means to vary the displacement of said one unit of said first hydrostatic transmission when said main electrical command signal and said first electrical feedback signal are indicative of different displacements.
Claim 6
Independent Claim
270 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, and first feedback signal generator means for providing a first electrical feedback signal which is indicative of the displacement of said one unit of said first hydrostatic transmission, said first control means including means for comparing said main electrical command signal and said first electrical feedback signal and for effecting operation of said first actuator means to vary the displacement of said one unit of said first hydrostatic transmission when said main electrical command signal and said first electrical feedback signal are indicative of different displacements.
Claim 7
Dependent Claim
95 words
An apparatus as set forth in claim 4 further including second feedback signal generator means for providing a second electrical feedback signal which is indicative of the displacement of said one unit of said second hydrostatic transmission, said second control means including means for comparing said main electrical command signal and said second electrical feedback signal and for effecting operation of said second actuator means to vary the displacement of said one unit of said second hydrostatic transmission when said main electrical command signal and said second electrical feedback signals are indicative of different displacements.
Claim 8
Dependent Claim
118 words
An apparatus as set forth in claim 5 further including first speed sensing means for providing a third electrical feedback signal which is indicative of the output speed of said first hydrostatic transmission, second speed sensing means for providing a fourth electrical feedback signal which is indicative of the output speed of said second hydrostatic transmission, and means for comparing said third and fourth electrical feedback signals and effecting operation of at least one of said actuator means to vary the displacement of at least said one of the unit of said first hydrostatic transmission when the output speed of one of said hydrostatic transmissions is greater than the output speed of the other of said hydrostatic transmissions.
Claim 9
Independent Claim
267 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, and first speed sensing means for providing a first electrical feedback signal which is indicative of the output speed of said first hydrostatic transmission, said first control means including means for comparing said main electrical command signal and said first electrical feedback signal and for effecting operation of said first actuator means to vary the displacement of said one unit of said first hydrostatic transmission when said main electrical command signal and said first electrical feedback signal are indicative of different output speeds.
Claim 10
Independent Claim
267 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, and first speed sensing means for providing a first electrical feedback signal which is indicative of the output speed of said first hydrostatic transmission, said first control means including means for comparing said main electrical command signal and said first electrical feedback signal and for effecting operation of said first actuator means to vary the displacement of said one unit of said first hydrostatic transmission when said main electrical command signal and said first electrical feedback signal are indicative of different output speeds.
Claim 11
Dependent Claim
92 words
An apparatus as set forth in claim 7 further including second speed sensing means for providing a second electrical feedback signal which is indicative of the output speed of said second hydrostatic transmission, said second control means including means for comparing said main electrical command signal and said second electrical feedback signal and for effecting operation of said second actuator means to vary the displacement of said one unit of said second hydrostatic transmission when said main electrical command signal and said second electrical feedback signal are indicative of different output speeds.
Claim 12
Dependent Claim
71 words
An apparatus as set forth in claim 8 further including means for comparing said first and second electrical feedback signals and effecting operation of at least one of said actuator means to vary the displacement of at least said one of the units of said first hydrostatic transmission when the output speed of one of said hydrostatic transmissions is greater than the output speed of the other of said hydrostatic transmissions.
Claim 13
Independent Claim
209 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, and acceleration limiter means for limiting the rate of change of said main electrical command signal upon operation of said main command signal generator means.
Claim 14
Independent Claim
209 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, and acceleration limiter means for limiting the rate of change of said main electrical command signal upon operation of said main command signal generator means.
Claim 15
Dependent Claim
27 words
An apparatus as set forth in claim 10 wherein said acceleration limiter means includes filter means for attenuating high frequency components of said main electrical command signal.
Claim 16
Independent Claim
245 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said secoNd hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, prime mover means for driving said pump units of said first and second hydrostatic transmissions, and anti-stall means for detecting when the output speed of said prime mover means decreases to a speed which is less than a predetermined reference speed to modify said main electrical command signal to reduce the output speed to which said main electrical command signal corresponds.
Claim 17
Independent Claim
245 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said secoNd hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, prime mover means for driving said pump units of said first and second hydrostatic transmissions, and anti-stall means for detecting when the output speed of said prime mover means decreases to a speed which is less than a predetermined reference speed to modify said main electrical command signal to reduce the output speed to which said main electrical command signal corresponds.
Claim 18
Dependent Claim
153 words
An apparatus as set forth in claim 12 wherein said prime mover means includes selectively settable throttle means for effecting variations in the output speed of said prime mover means as a function of variations in the setting of said throttle means, and said anti-stall means includes speed sensing means for providing an electrical speed signal which is indicative of the output speed of said prime mover means, throttle setting signal generator means for providing an electrical throttle setting signal which varies as a function of the setting of said throttle means, and means for comparing said electrical speed and throttle setting signals and for operating on said main electrical command signal to reduce the hydrostatic transmission output speed indicated by said main electrical command signal when said electrical speed signal indicates that the output speed of said prime mover is less than a predetermined function of the setting of said throttle means.
Claim 19
Independent Claim
240 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, and means for detecting when the output speed of one of said hydrostatic transmissions is different than the output speed of the other hydrostatic transmission for effecting operation of one of said actuator means to reduce the faster output speed and for effecting operation of the other said actuator means to increase the slower output speed.
Claim 20
Independent Claim
240 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, first electrical control means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal, and means for detecting when the output speed of one of said hydrostatic transmissions is different than the output speed of the other hydrostatic transmission for effecting operation of one of said actuator means to reduce the faster output speed and for effecting operation of the other said actuator means to increase the slower output speed.
Claim 21
Independent Claim
396 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of said pump and motor units of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic Transmissions to vary the output speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, said main command signal generator means including means for varying the value of said main electrical command signal between a first range of values corresponding to a relatively small displacement of said pump unit of said first hydrostatic transmission and relatively large displacement of said motor unit of said first hydrostatic transmission and a second range of values corresponding to relatively large displacement of said pump unit of said first hydrostatic transmission and relatively small displacement of said motor unit of said first hydrostatic transmission, first electrical control means for effecting operation of said first actuator means to vary the displacement of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, said first electrical control means including means for effecting operation of said first actuator means to vary only the displacement of said pump unit of said first hydrostatic transmission during variations in the value of said main electrical command signal in said first range of values, for effecting operation of said first actuator means to vary only the displacement of said motor unit of said first hydrostatic transmission during variations in the value of said main electrical command signal in said second range of values, and for effecting operation of said first actuator means to vary the displacements of both the pump and motor units of said first hydrostatic transmission during variations in the value of said main electrical command signal between said first and second ranges of value, and second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal.
Claim 22
Independent Claim
396 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of said pump and motor units of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic Transmissions to vary the output speed of said second hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said first and second hydrostatic transmissions, said main command signal generator means including means for varying the value of said main electrical command signal between a first range of values corresponding to a relatively small displacement of said pump unit of said first hydrostatic transmission and relatively large displacement of said motor unit of said first hydrostatic transmission and a second range of values corresponding to relatively large displacement of said pump unit of said first hydrostatic transmission and relatively small displacement of said motor unit of said first hydrostatic transmission, first electrical control means for effecting operation of said first actuator means to vary the displacement of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, said first electrical control means including means for effecting operation of said first actuator means to vary only the displacement of said pump unit of said first hydrostatic transmission during variations in the value of said main electrical command signal in said first range of values, for effecting operation of said first actuator means to vary only the displacement of said motor unit of said first hydrostatic transmission during variations in the value of said main electrical command signal in said second range of values, and for effecting operation of said first actuator means to vary the displacements of both the pump and motor units of said first hydrostatic transmission during variations in the value of said main electrical command signal between said first and second ranges of value, and second electrical control means for effecting operation of said second actuator means to vary the displacement of at least one of said units of said second hydrostatic transmission in response to variations in said main electrical command signal.
Claim 23
Dependent Claim
224 words
An apparatus as set forth in claim 15 wherein said second actuator means includes means for varying the displacement of said pump and motor units of said second hydrostatic transmission, said main command signal generator means includes means for varying the value of said main electrical command signal between a first range of values corresponding to a relatively small displacement of said pump units and relatively large displacements of said motor units in a second range of values corresponding to relatively large displacements of said pump units and relatively small displacement of said motor units, and said electrical control means includes means for effecting operation of said second actuator means to vary only the displacement of said pump unit of said second hydrostatic transmission during variations in the value of said main electrical command signal in said first range of values, for effecting operation of said second actuator means to vary only the displacement of said motor unit of said second hydrostatic transmission during variations in the value of said main electrical command signal in said second range of values, and for effecting operation of said second actuator means to vary the displacement of both the pump and motor units of said second hydrostatic transmission during variations in the value of said main electrical command signal between said first and second ranges of values.
Claim 24
Independent Claim
183 words
An apparatus comprising a plurality of transmissions having pump and motor units, first actuator means for varying the displacement of at least one of said units of said first hydrostatic transmission to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one of said units of said second hydrostatic transmission to vary the output speed of said second hydrostatic transmiSsion, first speed sensing means for providing a first electrical speed signal indicative of the output speed of said first hydrostatic transmission, second speed sensing means for providing a second electrical speed signal indicative of the output speed of said second hydrostatic transmission, means for comparing said first and second electrical speed signals to detect when one of said hydrostatic transmissions has a different output speed than the other hydrostatic transmission, and electrical control means for effecting operation of at least one of said actuator means to vary the displacement and output speed of at least one of said hydrostatic transmissions upon detection that said first and second hydrostatic transmissions have different output speeds.
Claim 25
Independent Claim
183 words
An apparatus comprising a plurality of transmissions having pump and motor units, first actuator means for varying the displacement of at least one of said units of said first hydrostatic transmission to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one of said units of said second hydrostatic transmission to vary the output speed of said second hydrostatic transmiSsion, first speed sensing means for providing a first electrical speed signal indicative of the output speed of said first hydrostatic transmission, second speed sensing means for providing a second electrical speed signal indicative of the output speed of said second hydrostatic transmission, means for comparing said first and second electrical speed signals to detect when one of said hydrostatic transmissions has a different output speed than the other hydrostatic transmission, and electrical control means for effecting operation of at least one of said actuator means to vary the displacement and output speed of at least one of said hydrostatic transmissions upon detection that said first and second hydrostatic transmissions have different output speeds.
Claim 26
Dependent Claim
130 words
An apparatus as set forth in claim 17 wherein said means for comparing said first and second electrical speed signals includes first and second channel means for receiving said first and second electrical speed signals, and switching means for transmitting electrical speed signals from said first speed sensing means to said first channel means and for transmitting electrical speed sensing signals from said second speed sensing means to said second channel means during forward operation of said first and second hydrostatic transmission, said switching means being operable to transmit electrical speed signals from said first speed sensing means to said second channel means and to transmit electrical speed signals from said second speed sensing means to said first channel means during reverse operation of said first and second hydrostatic transmissions.
Claim 27
Dependent Claim
86 words
An apparatus as set forth in claim 17 wherein said electrical control means includes means for effecting operation of one of said actuator means to increase the output speed of the slower one of said first and second hydrostatic transmissions upon detection of a difference in their output speeds and means for effecting operation of the other of said actuator means to decrease the output speed of the faster one of said first and second hydrostatic transmissions upon detection of a difference in their output speeds.
Claim 28
Dependent Claim
110 words
An apparatus as set forth in claim 17 wherein said first speed sensing means includes means for providing a first series of electrical pulses having a first pulse rate which varies as a function of the output speed of said first hydrostatic transmission, said second speed sensing means including means for providing a second series of electrical pulses having a second pulse rate which varies as a function of the output speed of said second hydrostatic transmission, said means for comparing said first and second electrical speed signals including means for providing an output signal which varies as a function of the difference between said first and second pulse rates.
Claim 29
Independent Claim
232 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said second hydrostatic transmission, main control means for effecting operation of said first and second actuator means to contemporaneously vary the displacement of at least one unit of each of said first and second hydrostatic transmissions by substantially equal amounts, speed equalizer means for detecting when the output speed of one of said hydrostatic transmissions is different than the output speed of the other hydrostatic transmission and for providing a control signal to effect operation of at least one of said actuator means to equalize the output speeds of said first and second hydrostatic transmissions in response to detection of a difference in their output speeds, secondary control means for effecting operation of at least one of said actuaTor means to vary the output speed of one of said hydrostatic transmissions relative to the output speed of the other hydrostatic transmission, and disabling means for rendering said speed equalizer means ineffective to provide a control signal upon operation of said secondary control means.
Claim 30
Independent Claim
232 words
An apparatus comprising a plurality of hydrostatic transmissions having pump and motor units, first actuator means for varying the displacement of at least one unit of a first one of said hydrostatic transmissions to vary the output speed of said first hydrostatic transmission, second actuator means for varying the displacement of at least one unit of a second one of said hydrostatic transmissions to vary the output speed of said second hydrostatic transmission, main control means for effecting operation of said first and second actuator means to contemporaneously vary the displacement of at least one unit of each of said first and second hydrostatic transmissions by substantially equal amounts, speed equalizer means for detecting when the output speed of one of said hydrostatic transmissions is different than the output speed of the other hydrostatic transmission and for providing a control signal to effect operation of at least one of said actuator means to equalize the output speeds of said first and second hydrostatic transmissions in response to detection of a difference in their output speeds, secondary control means for effecting operation of at least one of said actuaTor means to vary the output speed of one of said hydrostatic transmissions relative to the output speed of the other hydrostatic transmission, and disabling means for rendering said speed equalizer means ineffective to provide a control signal upon operation of said secondary control means.
Claim 31
Dependent Claim
112 words
An apparatus as set forth in claim 21 wherein said speed equalizer means includes first speed sensing means for providing a first speed signal which varies as a function of the output speed of said first hydrostatic transmission, second speed sensing means for providing a second speed signal which varies as a function of the output speed of said second hydrostatic transmission, and comparator means for comparing said first and second speed signals and providing said control signal when said first and second speed signals correspond to different speeds, said disabling means including means for preventing the transmission of speed signals to said comparator means upon operation of said secondary control means.
Claim 32
Independent Claim
204 words
An apparatus comprising a hydrostatic transmission having pump and motor units and adapted to be driven by an engine, actuator means for varying the displacement of at least one unit of said hydrostatic transmission to vary the output speed of said hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said hydrostatic transmission, electrical circuit means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, and anti-stall means for detecting the occurrence of an impending overloading the engine and for effecting a modification of the main electrical command signal to reduce the output speed of said hydrostatic transmission in response to detection of an impending overloading of the engine, said anti-stall means including throttle position signal generator means for providing a first electrical signal which is indicative of engine throttle position, speed signal generator means for providing a second electrical signal which is indicative of engine speed, and means for comparing said first and second electrical signals.
Claim 33
Independent Claim
204 words
An apparatus comprising a hydrostatic transmission having pump and motor units and adapted to be driven by an engine, actuator means for varying the displacement of at least one unit of said hydrostatic transmission to vary the output speed of said hydrostatic transmission, main command signal generator means for providing a main electrical command signal which is variable to correspond to any one of a plurality of output speeds and displacements of said hydrostatic transmission, electrical circuit means for effecting operation of said first actuator means to vary the displacement of at least one of said units of said first hydrostatic transmission in response to variations in said main electrical command signal, and anti-stall means for detecting the occurrence of an impending overloading the engine and for effecting a modification of the main electrical command signal to reduce the output speed of said hydrostatic transmission in response to detection of an impending overloading of the engine, said anti-stall means including throttle position signal generator means for providing a first electrical signal which is indicative of engine throttle position, speed signal generator means for providing a second electrical signal which is indicative of engine speed, and means for comparing said first and second electrical signals.
Claim 34
Dependent Claim
34 words
An apparatus as set forth in claim 23 wherein said speed signal generator means includes means for providing a series of pulses having a pulse rate which varies as a function of engine speed.
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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |