Patent US2655894A successfully refreshed from Google Patents.
US3757130A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overspeed preventive apparatus for engines
Assignee: Hitachi Ltd
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Filing: 1970-12-16
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Granted: 1973-09-04
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Expires: 1990-12-16
Abstract
Abstract An electro-hydraulic overspeed preventive apparatus for an engine in which two overspeed preventive control systems are provided in addition to a speed control system including a working fluid flow regulating valve disposed at the inlet of the engine and means for controlling the opening of the working fluid flow regulating valve in response to an error signal representative of the deviation of the actual speed from the desired speed. The two overspeed preventive control systems respectively are operated to close the working fluid flow regulating valve prior to the operation of the speed control system when the acceleration signal representative of the actual acceleration exceeds a predetermined limit and when the difference between two signals respectively representative of the state of flow of the working fluid and the electrical output of the load exceeds a predetermined limit.
Inventors
- 👤 K Takemura
- 👤 T Kishigami
- 👤 Y Uchiyama
- 👤 A Yasumoto
- 👤 M Huzieda
- 👤 R Arie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 01:20
CPC Classifications
H; H02; H02P; H02P23/00; H02P23/16
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
244 words
An apparatus for preventing an engine from overspeed comprising: a working fluid flow regulating valve disposed at the inlet of the engine; first means, responsive to the speed of the engine, for detecting a deviation between the actual speed of the engine and a predetermined speed, and for selectively controlling the opening and closing of said working fluid flow regulating valve in response to said deviation; second means, responsive to the rate of change of the speed of the engine, for detecting a deviation between the actual acceleration of the engine and a predetermined acceleration and for generating a first electrical signal representative of said deviation; third means, responsive to the state of flow of the working fluid passing through said engine, for generating a second electrical signal representative thereof; fourth means, responsive to the output load of said engine for generating a third electrical signal representative thereof; fifth means, coupled to the outputs of said third and fourth means, for combining said second and third electrical signals and for generating a fourth electrical signal when said combined second and third electrical signals exceed a predetermined fixed value; and sixth means, coupled to said second and fifth means, for controlling the rapid opening and closing of said working fluid flow regulating valve, in response at least one of said first and fourth electrical signals, independently of the control of the opening and closing of said working fluid flow regulating valve by said first means.
Claim 2
Independent Claim
244 words
An apparatus for preventing an engine from overspeed comprising: a working fluid flow regulating valve disposed at the inlet of the engine; first means, responsive to the speed of the engine, for detecting a deviation between the actual speed of the engine and a predetermined speed, and for selectively controlling the opening and closing of said working fluid flow regulating valve in response to said deviation; second means, responsive to the rate of change of the speed of the engine, for detecting a deviation between the actual acceleration of the engine and a predetermined acceleration and for generating a first electrical signal representative of said deviation; third means, responsive to the state of flow of the working fluid passing through said engine, for generating a second electrical signal representative thereof; fourth means, responsive to the output load of said engine for generating a third electrical signal representative thereof; fifth means, coupled to the outputs of said third and fourth means, for combining said second and third electrical signals and for generating a fourth electrical signal when said combined second and third electrical signals exceed a predetermined fixed value; and sixth means, coupled to said second and fifth means, for controlling the rapid opening and closing of said working fluid flow regulating valve, in response at least one of said first and fourth electrical signals, independently of the control of the opening and closing of said working fluid flow regulating valve by said first means.
Claim 3
Dependent Claim
74 words
An apparatus according to claim 1, wherein said first means includes a hydraulic servo valve means, coupled to said working fluid flow regulating valve, for controlling the opening of said working fluid flow regulating valve, and wherein said sixth means includes a dumping valve, coupled to said hydraulic servo valve means, for draining hydraulic fluid from said hydraulic servo valve means, in response to at least one of said first and fourth electrical signals.
Claim 4
Dependent Claim
73 words
An apparatus according to claim 1, wherein said first means includes valve actuator means, coupled to said working fluid flow regulating valve, for controlling the actuating thereof in response to an electrical signal applied thereto, and further including seventh means coupled to said first means, for generating a fifth electrical signal to be supplied to said valve actuator means, in response to the rate of change of said deviation exceeding a preselected amount.
Claim 5
Dependent Claim
97 words
An apparatus according to claim 1, wherein said second and fifth means include means for enabling the generation of said first and fourth electrical signals prior to the selective control by said first means in response to the cut-off of a high load from said engine, while preventing the generation of said first and fourth electrical signals in response to the cut-off of a relatively lower load from said engine, to thereby permit said first means to control the opening and closing of said working fluid flow regulating valve at a cut-off of a relatively lower load.
Claim 6
Dependent Claim
97 words
An apparatus according to claim 2, wherein said second and fifth means include means for enabling the generation of said first and fourth electrical signals prior to the selective control by said first means in response to the cut-off of a high load from said engine, while preventing the generation of said first and fourth electrical signals in response to the cut-off of a relatively lower load from said engine, to thereby permit said first means to control the opening and closing of said working fluid flow regulating Valve at a cut-off of a relatively lower load.
Claim 7
Dependent Claim
73 words
An apparatus according to claim 5, wherein said first means includes valve actuator means, coupled to said working fluid flow regulating valve, for controlling the actuating thereof in response to an electrical signal applied thereto, and further including seventh means coupled to said first means, for generating a fifth electrical signal to be supplied to said valve actuator means, in response to the rate of change of said deviation exceeding a preselected amount.
Claim 8
Dependent Claim
73 words
An apparatus according to claim 2, wherein said first means includes valve actuator means, coupled to said working fluid flow regulating valve, for controlling the actuating thereof in response to an electrical signal applied thereto, and further including seventh means coupled to said first means, for generating a fifth electrical signal to be supplied to said valve actuator means, in response to the rate of change of said deviation exceeding a preselected amount.
Claim 9
Dependent Claim
57 words
An apparatus according to claim 7, further including delay means, coupled between at least one of said second and fifth means and said sixth means, for continuing the actuation of said dumping valve until a sufficiently large signal for closing said working fluid flow regulating valve is supplied from said first means through said servo valve means.
Claim 10
Dependent Claim
24 words
An apparatus according to claim 8, wherein said delay means is coupled between each of said second and fifth means and said sixth means.
Claim 11
Dependent Claim
69 words
An apparatus according to claim 8, wherein said fifth means comprises a first summing amplifier to which said second and third signals are applied, a first comparator circuit for comparing the output of said first summing amplifier with a first reference voltage and a first solenoid switch coupled to the output of said first comparator circuit for enabling the coupling of said fourth electrical signal to said sixth means.
Claim 12
Dependent Claim
74 words
An apparatus according to claim 10, wherein said second means comprises a first differentiator circuit to which a signal representative of the actual speed of the engine is applied, a second comparator circuit for comparing the output of said first differentiator circuit with a second reference voltage and a second solenoid switch coupled to the output of said second comparator circuit for enabling the coupling of said first electrical signal to said sixth means.
Claim 13
Dependent Claim
59 words
An apparatus according to claim 11, wherein said seventh means comprises a second differentiator circuit to which a signal representative of said speed deviation is applied and a voltage threshold responsive amplifier circuit for enabling the generation of said fifth signal to be supplied to said valve actuator means when the load of the engine has been cut off.
Claim 14
Dependent Claim
56 words
An apparatus according to claim 12, wherein each of said delay means comprises a pair of solenoid switches the windings of which are connected in parallel with a slow release contact responsive to one of said windings, coupled to the supply line therefor, while the output of the other winding is connected to said sixth means.
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) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |