US3789280A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multicable drum hoisting system
Assignee: Westinghouse Canada Inc
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Filing: 1971-10-19
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Granted: 1974-01-29
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Expires: 1991-10-19
Abstract
Abstract This invention relates to a multi-rope drum hoist wherein two conveyances are to be moved in opposite directions by the hoisting machinery at the same time. Each conveyance is hoisted by the use of two or more ropes, and the tension in the two ropes is equalized by providing a separate hoisting machine for each rope and coupling the hoisting machinery together electrically so that the torque outputs of the respective driving motors driving the separate hoists are essentially equal, thus assuring equal tension in the hoisting ropes.
Inventors
- 👤 E Oldfield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:57
CPC Classifications
H; H02; H02P; H02P5/00; H02P5/68; B; B61; B61B; B61B12/00; B61B12/10; B66; B66B; B66B1/00; B66B1/24; B66B1/28; B66B1/30; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/282
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
124 words
A master-slave motor system comprising a first electromechanical apparatus including a master motor drivingly coupled to a hoist device, an associated hoisting cable and a load to be lifted and lowered; at least one additional electro-mechanical apparatus including a slave motor drivingly coupled to a corresponding hoist device and hoisting cable, and said load; whereby said hoist devices and hoisting cables operate in a parallel load sharing relation with said load; means responsive to a variable of the master motor for providiNg a command signal proportional to the output torque of the master motor; and control means responsive to the command signal for controlling the slave motor to maintain its output torque in a predetermined relationship with the output torque of the master motor.
Claim 2
Dependent Claim
124 words
A master-slave motor system comprising a first electromechanical apparatus including a master motor drivingly coupled to a hoist device, an associated hoisting cable and a load to be lifted and lowered; at least one additional electro-mechanical apparatus including a slave motor drivingly coupled to a corresponding hoist device and hoisting cable, and said load; whereby said hoist devices and hoisting cables operate in a parallel load sharing relation with said load; means responsive to a variable of the master motor for providiNg a command signal proportional to the output torque of the master motor; and control means responsive to the command signal for controlling the slave motor to maintain its output torque in a predetermined relationship with the output torque of the master motor.
Claim 3
Dependent Claim
12 words
The system of claim 1, wherein said predetermined relationship is torque equality.
Claim 4
Dependent Claim
28 words
The system of claim 1, wherein each of said hoist devices is a drum hoist and each of said associated hoisting cables is wound on a corresponding drum.
Claim 5
Dependent Claim
82 words
The system of claim 3 wherein in at least one of said electromechanical apparatus the associated hoist device is coupled with a second drum, said second drum being coupled to a second load through a second hoisting cable; wherein said second hoisting cable is wound on said second drum in the opposite direction as compared to the associated drum and hoisting cable within said one electromechanical apparatus; and with the former load being lifted when the latter said second load is lowered.
Claim 6
Dependent Claim
39 words
The system of claim 4 wherein a second drum and a second hoisting cable are provided in each of said electromechanical apparatus, each of said second drums and second hoisting cables being coupled in common to said second load.
Claim 7
Dependent Claim
36 words
The system of claim 1, wherein each of said master and slave motors is a DC motor having an apparatus current and voltage supply and a field excitation provided from a supply including semiconductor controlled rectifiers.
Claim 8
Dependent Claim
109 words
A master-slave motor system comprising a master motor drivingly coupled to a first hoist having a hoisting cable, a slave motor drivingly coupled to a second hoist having a hoisting cable, both hoisting cables being coupled to a common load, whereby both hoists operate in parallel in load sharing relation to one lifting and lowering the load, means responsive to a variable of the master motor for providing a command signal proportional to the output torque of the master motor, and control means responsive to the command signal for controlling the slave motor to maintain its output torque in predetermined relation with the output torque of the master motor.
Claim 9
Dependent Claim
109 words
A master-slave motor system comprising a master motor drivingly coupled to a first hoist having a hoisting cable, a slave motor drivingly coupled to a second hoist having a hoisting cable, both hoisting cables being coupled to a common load, whereby both hoists operate in parallel in load sharing relation to one lifting and lowering the load, means responsive to a variable of the master motor for providing a command signal proportional to the output torque of the master motor, and control means responsive to the command signal for controlling the slave motor to maintain its output torque in predetermined relation with the output torque of the master motor.
Claim 10
Dependent Claim
12 words
The combination as in claim 7 wherein said predetermined relation is equality.
Claim 11
Dependent Claim
13 words
The combination as in claim 7 wherein said variable is motor armature current.
Claim 12
Dependent Claim
51 words
The combination as in claim 9 wherein there is means for providing a feedback signal responsive to the armature current of the slave motor, and said control means is responsive to the feedback signal for maintaining the torque output of the slave motor at the value dictated by the command signal.
Claim 13
Dependent Claim
58 words
The combination as in claim 9 wherein there is means for providing a feedback signal responsive to the armature current of the slave motor, and said control means comprises a current regulating system wherein the command and feedback signals are compared to produce an error signal, and means responsive to said error signal for controlling the slave 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) | 1977-01-28 | 1977-07-30 | 1978-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-28 | 1981-07-30 | 1982-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-28 | 1985-07-30 | 1986-01-29 | $7700.00 | Window Closed / Lapsed |