Patent US3760591A successfully refreshed from Google Patents.
US3760591A
Expired / Lapsed
US
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Hydraulic-electric control system for hydraulic motor
Assignee: Harnischfeger Corp
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Filing: 1971-12-27
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Granted: 1973-09-25
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Expires: 1991-12-27
Abstract
Abstract A hydraulic motor is driven by hydraulic fluid supplied by a hydraulic pump. The pump has a servo-stem control thereon which regulates fluid flow to the motor and thereby controls motor speed and direction of rotation. The servo-stem control is operated by a movable spring-centered piston of a hydraulic actuator. The actuator piston is movable in response to fluid flow conditions in a rotary servo-system which comprises a hydraulic sensing motor (driven by the hydraulic motor) and a control pump which supplies fluid to the sensing motor. The direction, speed and degree of rotation of the control pump regulates the direction, speed and degree of rotation of the hydraulic motor. The control pump is driven by an electric stepping motor and the latter is operated by electric control means. The electric control means comprise variable frequency pulse generating means to establish stepping motor speed and pulse counting means to establish the extent of stepping motor rotation. The electric control means also includes selector switches for presetting a predetermined direction, speed and degree of rotation for the stepping motor. The hydraulic motor is used to drive a movable bridge member of an overhead crane.
Inventors
- 👤 R Gordon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:39
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/46; F16H61/47; Y; Y10; Y10S; Y10S60/00; Y10S60/911
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
169 words
In a control system for a main hydraulic motor which is adapted to be supplied with hydraulic fluid from a main hydraulic pump and is adapted to move a component in at least one direction at some predetermined rate of speed for some predetermined distance; hydraulic control means, including a fixed volume variable speed hydraulic control pump, for controlling the rate of fluid flow from said main motor to thereby regulate the speed of said main motor and said component, said hydraulic control means further controlling the duration of fluid flow from said main pump to said main motor to thereby regulate the distance said main motor moves said component; an electric stepping motor for rotating said control pump at some predetermined rate of speed for some predetermined angular distance to thereby regulate the speed and distance of movement of said component, respectively, and electric control means for controlling operation of said stepping motor to effect rotation thereof at a predetermined rate of speed for a predetermined angular distance.
Claim 2
Dependent Claim
169 words
In a control system for a main hydraulic motor which is adapted to be supplied with hydraulic fluid from a main hydraulic pump and is adapted to move a component in at least one direction at some predetermined rate of speed for some predetermined distance; hydraulic control means, including a fixed volume variable speed hydraulic control pump, for controlling the rate of fluid flow from said main motor to thereby regulate the speed of said main motor and said component, said hydraulic control means further controlling the duration of fluid flow from said main pump to said main motor to thereby regulate the distance said main motor moves said component; an electric stepping motor for rotating said control pump at some predetermined rate of speed for some predetermined angular distance to thereby regulate the speed and distance of movement of said component, respectively, and electric control means for controlling operation of said stepping motor to effect rotation thereof at a predetermined rate of speed for a predetermined angular distance.
Claim 3
Dependent Claim
55 words
A control system according to claim 1 wherein said electric control means comprises first means, including a speed selector switch, for effecting rotation of said stepping motor at a predetermined rate of speed, and further compRises second means, including a distance selector switch, for effecting rotation of said stepping motor for a predetermined angular distance.
Claim 4
Dependent Claim
43 words
A control system according to claim 2 wherein said first means comprises variable frequency pulse generating means for generating a series of pulses and wherein said second means comprises counter means for providing a predetermined number of said pulses to said stepping motor.
Claim 5
Dependent Claim
70 words
A control system according to claim 3 wherein said main hydraulic motor is rotatable in either of two directions; wherein said component is movable in either of two directions; wherein said control pump and said stepping motor are both rotatable in either of two directions; and wherein said electric control means comprises third means, including a direction selector switch, for effecting rotation of said stepping motor in a predetermined direction.
Claim 6
Dependent Claim
213 words
In combination: a main hydraulic motor adapted to move a component in either of two directions at a predetermined rate of speed for a predetermined distance; a main hydraulic pump for supplying hydraulic fluid to said main motor; said main pump having a servo-stem control means thereon which is movable to control the direction, rate and duration of fluid flow to said main motor to thereby regulate the direction, rate, and distance of movement of said component; a hydraulic actuator for operating said servo-stem control means; a hydraulic speed sensing motor driven by said main motor; a fixed volume variable speed hydraulic control pump for supplying hydraulic fluid to said speed sensing motor through a pair of hydraulic fluid lines; said hydraulic actuator being connected to said lines and responsive to fluid pressure conditions therein to operate said servo-stem control means on said main pump; an electric stepping motor for rotating said control pump in a predetermined direction at some predetermined rate of speed for some predetermined angular distance to thereby regulate the direction, speed and distance of movement of said component, respectively; and electric control means for controlling operation of said stepping motor to effect rotation thereof in a predetermined direction at a predetermined rate of speed for a predetermined angular distance.
Claim 7
Dependent Claim
213 words
In combination: a main hydraulic motor adapted to move a component in either of two directions at a predetermined rate of speed for a predetermined distance; a main hydraulic pump for supplying hydraulic fluid to said main motor; said main pump having a servo-stem control means thereon which is movable to control the direction, rate and duration of fluid flow to said main motor to thereby regulate the direction, rate, and distance of movement of said component; a hydraulic actuator for operating said servo-stem control means; a hydraulic speed sensing motor driven by said main motor; a fixed volume variable speed hydraulic control pump for supplying hydraulic fluid to said speed sensing motor through a pair of hydraulic fluid lines; said hydraulic actuator being connected to said lines and responsive to fluid pressure conditions therein to operate said servo-stem control means on said main pump; an electric stepping motor for rotating said control pump in a predetermined direction at some predetermined rate of speed for some predetermined angular distance to thereby regulate the direction, speed and distance of movement of said component, respectively; and electric control means for controlling operation of said stepping motor to effect rotation thereof in a predetermined direction at a predetermined rate of speed for a predetermined angular distance.
Claim 8
Dependent Claim
70 words
A combination according to claim 5 wherein said electric control means comprises first means, including a speed selector switch, for effecting rotation of said stepping motor at a predetermined rate of speed; second means, including a distance selector switch, for effecting rotation of said stepping motor through a predetermined angular distance; and third means, including a direction selector switch, for effecting rotation of said stepping motor in a predetermined direction.
Claim 9
Dependent Claim
42 words
A combination according to claim 6 wherein said first means comprises variable frequency pulse generating means for generating a series of pulses and wherein said second means comprises counter means for providing a predetermined number of said pulses to said stepping motor.
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) | 1976-09-24 | 1977-03-26 | 1977-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-24 | 1981-03-26 | 1981-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-24 | 1985-03-26 | 1985-09-25 | $7700.00 | Window Closed / Lapsed |