US3847251A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control apparatus for a powered hoist
Assignee: Northrop Grumman Properties Ltd
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Filing: 1973-03-20
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Granted: 1974-11-12
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Expires: 1993-03-20
Abstract
Abstract A control apparatus for a powered hoist which has a winch drum, a variable torque motor for driving the drum, and a brake for the drum, includes a device for detecting the load torque applied by the drum to the brake, when the latter is engaged, a circuit for increasing the torque of the motor and for releasing the brake only when the motor torque exceeds the load torque, and a circuit for varying the motor torque when the brake has been released.
Inventors
- 👤 J Binns
- 👤 K Ellis
- 👤 D Craven
- 👤 P Maltby
- 👤 S Glaze
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:21
CPC Classifications
B; B66; B66C; B66C13/00; B66C13/18; B66C13/22; B66C13/23
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
115 words
A control apparatus for a powered hoist having a winch drum, a motor capable of variable output for driving the drum and a brake for the drum, said control apparatus comprising means for detecting a first torque applied by the drum to the brake when the latter is engaged to arrest the drum, control means for causing a second torque supplied by said driving motor to be increased, brake control means responsive to movement of said drum by said second torque, said brake control means for releasing said brake only when the second torque exceeds the first torque, and further control means, operative only when the brake has been released, for modifying the second torque.
Claim 2
Dependent Claim
115 words
A control apparatus for a powered hoist having a winch drum, a motor capable of variable output for driving the drum and a brake for the drum, said control apparatus comprising means for detecting a first torque applied by the drum to the brake when the latter is engaged to arrest the drum, control means for causing a second torque supplied by said driving motor to be increased, brake control means responsive to movement of said drum by said second torque, said brake control means for releasing said brake only when the second torque exceeds the first torque, and further control means, operative only when the brake has been released, for modifying the second torque.
Claim 3
Dependent Claim
133 words
A control apparatus for a powered hoist having a winch drum, a motor capable of variable output for driving the drum and a brake for the drum, said control apparatus comprising means for generating a first electrical signal dependent on a first torque which is applied by the drum to the brake when the latter is engaged to arrest the drum, means responsive to the magnitude of said first electrical signal to generate a second electrical signal, said motor supplying a second torque, means for increasing said second torque at a rate dependent on the magnitude of said second electrical signal, means for releasing said brake only when the second torque exceeds the first torque, and further control means, operative only when the brake has been released, for modifying the second electrical signal.
Claim 4
Dependent Claim
133 words
A control apparatus for a powered hoist having a winch drum, a motor capable of variable output for driving the drum and a brake for the drum, said control apparatus comprising means for generating a first electrical signal dependent on a first torque which is applied by the drum to the brake when the latter is engaged to arrest the drum, means responsive to the magnitude of said first electrical signal to generate a second electrical signal, said motor supplying a second torque, means for increasing said second torque at a rate dependent on the magnitude of said second electrical signal, means for releasing said brake only when the second torque exceeds the first torque, and further control means, operative only when the brake has been released, for modifying the second electrical signal.
Claim 5
Dependent Claim
27 words
An apparatus as claimed in claim 2 which includes a synchro motor responsive to said second electrical signal to vary said second torque from said driving motor.
Claim 6
Dependent Claim
55 words
An apparatus as claimed in claim 3 in which said means for releasing the brake comprises a first switching means, operable by the brake, when a part thereof is urged against said first torque by said second torque, to provide a third electrical signal, said brake being released in response to said third electrical signal.
Claim 7
Dependent Claim
38 words
An apparatus as claimed in claim 4 which includes second switching means responsive to said third electrical signal to provide a fourth electrical signal, and an electro-magnet device responsive to said fourth electrical signal to release said brake.
Claim 8
Dependent Claim
31 words
An apparatus as claimed in claim 5 which includes third switching means responsive to said third electrical signal to isolate said first electrical signal from said second electrical signal generating means.
Claim 9
Dependent Claim
39 words
An apparatus as claimed in claim 5 which includes means for generating a fifth electrical signal dependent on the rotational speed of said drum, said means for generating the second electrical signal being responsive to said fifth electrical signal.
Claim 10
Dependent Claim
51 words
An apparatus as claimed in claim 7 in which said means for modifying the second torque includes means for generating a sixth electrical signal dependent on a desired speed and directioN of rotation of said drum, said means for generating the second electrical signal being responsive to said sixth electrical signal.
Claim 11
Dependent Claim
40 words
An apparatus as claimed in claim 8 which includes fourth switching means operable when said drum has reached a permitted limit of its rotation in either direction, for isolating said sixth electrical signal from said second electrical signal generating means.
Claim 12
Dependent Claim
43 words
An apparatus as claimed in claim 9 in which said second electrical signal generating means includes means for summing said fifth and sixth electrical signals and a first amplifier responsive to the output of said summing means to provide an eighth electrical signal.
Claim 13
Dependent Claim
39 words
An apparatus as claimed in claim 10 in which said second electrical signal generating means includes a further amplifier responsive to said eighth electrical signal and to the output of said summing means to provide said second electrical signal.
Claim 14
Dependent Claim
34 words
An apparatus as claimed in claim 11 which includes means for generating a feedback signal dependent on the rotational position of said synchro motor, said further amplifier also being responsive to said feedback signal.
Claim 15
Dependent Claim
54 words
An apparatus as claimed in claim 12 which includes fifth switching means responsive to said third electrical signal to isolate said further amplifier from the output of said summing means, whereby said further amplifier is responsive only to said eighth electrical signal only when said first switching means is not operated by said brake.
Claim 16
Dependent Claim
83 words
An apparatus as claimed in claim 11 which includes a feedback arrangement associated with said first amplifier to cause the latter to operate as an integrator, and sixth switching means responsive to operation of said sixth electrical signal generating means and to operation of said fourth switching means to render said feedback arrangement operative, whereby said first amplifier acts as an integrator when said sixth electrical signal is present and when said drum is not at one of its limits of angular rotation.
Claim 17
Dependent Claim
101 words
An apparatus as claimed in claim 14 which includes a logic circuit responsive to said fifth electrical signal and to operation of said fourth switching means and said sixth electrical signal generating means, to generate a ninth electrical signal, whereby said ninth electrical signal is present only in the presence of said sixth electrical signal and when said drum is not at one of its limits of rotation, and a plurality of latching circuits responsive to said ninth electrical signal to cancel said third and fourth electrical signals and to cause said sixth switching means to render said feedback arrangement inoperative.
Claim 18
Dependent Claim
62 words
An apparatus as claimed in claim 15, in combination with a further, similar, control apparatus for a further powered hoist, similar to the first-mentioned hoist, and an interconnection arrangement energisable to cause said control apparatus to coact, whereby the second torque supplied by both of said driving motors may be modified by the torque modifying means of one of said control apparatuses.
Claim 19
Dependent Claim
36 words
A combination as claimed in claim 16 which includes seventh switching means operable to provide a tenth electrical signal, said interconnection arrangement being responsive to said tenth electrical signal to cause said control apparatuses to coact.
Claim 20
Dependent Claim
112 words
A combination as claimed in claim 17 in which said interconnection arrangement includes a second logic circuit responsive to said third electrical signal and to said tenth electrical signal to provide an eleventh electrical signal, said fourth switching means and a corresponding switching means in said further control apparatus being responsive to said eleventh electrical signal, whereby, when said seventh switching means is operated, and said first switch means and a corresponding switching means in said further apparatus is operated, said sixth electrical signal, and a corresponding signal in said further apparatus, are respectively isolated from said second electrical signal generating means and from a corResponding generating means in said further apparatus.
Claim 21
Dependent Claim
60 words
A combination as claimed in claim 18 which includes eighth switching means, corresponding to said first switching means and operable by the brake of said further powered hoist to provide a twelfth electrical signal, and in which said second logic circuit includes a further latching circuit responsive to said ninth and twelfth electrical signals to render said interconnection arrangement inoperative.
Claim 22
Dependent Claim
79 words
A combination as claimed in claim 19 in which said interconnection arrangement includes first and second means responsive to the rotational positions of the respective drums to provide thirteenth and fourteenth electrical signals, second summing means responsive to said thirteenth and fourteenth electrical signals to provide a fifteenth electrical signal, and first and second modifying means for respectively modifying said sixth electrical signal, and a corresponding signal in said further control apparatus, in accordance with said fifteenth electrical signal.
Claim 23
Dependent Claim
81 words
A combination as claimed in claim 20 which includes means for generating a sixteenth electrical signal dependent on the torque applied by the drum of said further hoist to the brake thereof when the latter is engaged, and ninth and tenth switching means responsive to said first and sixteenth electrical signals and to said tenth electrical signal and respectively operable to isolate said fifteenth electrical signal from said sixth electrical signal and from the corresponding signal in said further control apparatus.
Claim 24
Dependent Claim
31 words
A combination as claimed in claim 20 which includes means for modifying said thirteenth and fourteenth electrical signals in accordance with a desired difference in the rotational positions of said drums.
Claim 25
Dependent Claim
44 words
A combination as claimed in claim 17 which includes means for interconnecting said sixth electrical signal generating means and the corresponding generating means in said further control apparatus, and eleventh switching means responsive to said tenth electrical signal to render said interconnecting means inoperative.
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) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |