Patent US3679180A successfully refreshed from Google Patents.
US3679180A
Expired / Lapsed
US
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Cable control system
Assignee: Department of National Defence
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Filing: 1969-10-17
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Granted: 1972-07-25
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Expires: 1989-10-17
Abstract
Abstract This application discloses means for maintaining a desired tension in a cable used to winch a helicopter down to the deck of a ship. In the system described, a cable accumulator is used interposed between the helicopter and a constant tension haul down winch. This cable accumulator stores a variable amount of cable to provide a snatch-absorbing facility. In a control system for the winch, the tension in the cable is sensed and utilized, but in addition two transducers measure the cable velocity respectively on opposite sides of the cable accumulator. The difference between the outputs of the two transducers provides an anticipatory control term.
Inventors
- 👤 Joseph C Callaghan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:36
CPC Classifications
B; B64; B64F; B64F1/00; B64F1/12; B64F1/125; B66; B66D; B66D1/00; B66D1/28; B66D1/40; B66D1/48; B66D2700/00; B66D2700/01; B66D2700/0108; Y; Y10; Y10S; Y10S254/00; Y10S254/90
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
310 words
Means for maintaining a desired tension in a length of cable comprising: a. a cable tensioning winch; b. a reversible driving motor for that winch; c. winch control means for the driving motor; d. tension sensing means arranged to monitor the actual tension in the said length of cable; e. tension setting means arranged to provide a signal representative of a desired cable tension; f. a cable accumulator arranged to store a bight or loop of the said cable at a point intermediate the winch and the said length of cable; g. the accumulator being such that the amount of cable stored in the bight or loop can vary from instant to instant to provide a snatch-absorbing and shock-absorbing facility; h. a first device providing an output signal indicative of the actual winch speed; i. a second device acting upon a part of the cable between the accumulator and the said length of cable and providing an output signal indicative of the actual velocity of the said length of cable; j. control means arranged to receive the outputs from the first device, the second device, the output from the tension sensing means; these control means in accordance with their inputs being effective to control the direcTion and speed of operation of the driving motor for the winch in a manner producing the desired tension in the said length of cable; k. said control means combining the output of the first device and the output of the second device to produce a signal indicative of whether the cable is being paid-out or taken-in by the winch at a faster rate, or at a slower rate, than the cable passing from the cable accumulator to the said length of cable, thus sensing the difference of the speed of said first and second outputs providing an anticipatory control to the winch control means.
Claim 2
Dependent Claim
310 words
Means for maintaining a desired tension in a length of cable comprising: a. a cable tensioning winch; b. a reversible driving motor for that winch; c. winch control means for the driving motor; d. tension sensing means arranged to monitor the actual tension in the said length of cable; e. tension setting means arranged to provide a signal representative of a desired cable tension; f. a cable accumulator arranged to store a bight or loop of the said cable at a point intermediate the winch and the said length of cable; g. the accumulator being such that the amount of cable stored in the bight or loop can vary from instant to instant to provide a snatch-absorbing and shock-absorbing facility; h. a first device providing an output signal indicative of the actual winch speed; i. a second device acting upon a part of the cable between the accumulator and the said length of cable and providing an output signal indicative of the actual velocity of the said length of cable; j. control means arranged to receive the outputs from the first device, the second device, the output from the tension sensing means; these control means in accordance with their inputs being effective to control the direcTion and speed of operation of the driving motor for the winch in a manner producing the desired tension in the said length of cable; k. said control means combining the output of the first device and the output of the second device to produce a signal indicative of whether the cable is being paid-out or taken-in by the winch at a faster rate, or at a slower rate, than the cable passing from the cable accumulator to the said length of cable, thus sensing the difference of the speed of said first and second outputs providing an anticipatory control to the winch control means.
Claim 3
Dependent Claim
100 words
Tension maintaining means according to claim 1, and in which: a. the first device is a tachogenerator; b. the second device is a tachogenerator; c. each tachogenerator provides a direct current the polarity of which depends upon the direction of rotation of the tachogenerator and the magnitude of which depends upon the speed of rotation of the tachogenerator; d. the outputs of the two tachogenerators are applied in opposition to produce a direct current signal the polarity of which indicates which tachogenerator is running the faster and the magnitude of which indicates the difference in speed between the two tachogenerators.
Claim 4
Dependent Claim
115 words
Tension maintaining means according to claim 1, and in which: a. the control means for the motor are themselves subjected to a primary control; b. that primary control is determined by the outputs of the tension sensing and the tension setting means; c. that primary control is effective under steady operating conditions to maintain the actual tension substantially equal to the desired tension; d. the control means for the motor are themselves subjected to a secondary control; e. that secondary control is determined by the outputs of the first device and the second device; and f. that secondary control is effective under rapidly changing operating conditions to provide an anticipatory correction of the winch speed.
Claim 5
Dependent Claim
72 words
Tension maintaining means according to claim 3, and in which: a. the control means include an electromagnetically-operated hydraulic valve; b. that valve has a first operating winding; c. a primary control current is applied to the first operating winding to provide the said primary control; d. that valve has a second operating winding; and e. a secondary control current is applied to the second operating winding to provide the said secondary control.
Claim 6
Dependent Claim
101 words
Tension maintaining means according to claim 4, and in which: a. the hydraulic valve is a spool valve; b. the hydraulic valve includes a flapper valve; c. the two operating windings are arranged to control movement of the flapper valve; d. the spool valve includes piston surfaces; e. the flapper valve selectively applies hydraulic pressure to piston surfaces of the spool valve to reposition the valve spool; and f. the valve spool is mechanically linked with the flapper valve in such a manner that the spool is biased to a position which corresponds with the net output of the two windings.
Claim 7
Dependent Claim
143 words
Tension maintaining means according to claim 5, and in which: a. the control means include a double-ended hydraulic cylinder containing a piston; b. the spool of the hydraulic valve is arranged to control the flow of hydraulic fluid to and from the ends of that cylinder; c. a variable speed hydraulic motor forms the said reversible driving motor for the winch; d. a hydraulic pump is arranged to supply hydraulic fluid to drive the said hydraulic motor; e. a constant speed electric motor is arranged to drive the said hydraulic pump; f. a tilt-head or swash plate of the hydraulic pump determines by its position the flow and the direction of flow of hydraulic fluid between the pump and the motor; and g. the said piston is coupled to and thus by its position controls the position of the tilt-head or swash plate.
Claim 8
Dependent Claim
34 words
Tension maintaining means according to claim 1, and In which the tension setting means includes a manual control which can be reset during continuous operation of the winch to change the desired cable tension.
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) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |