US2300343A

US2300343A - Hoisting mechanism

Info

Publication number: US2300343A
Application number: US375819A
Authority: US
Inventors: Murray G Clay
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-01-24
Filing date: 1941-01-24
Publication date: 1942-10-27
Anticipated expiration: 1959-10-27

Description

Oct. 27, 1 942.

M. G. CLAY ,300,

HOISTING MECHANISM Filed Jan. 24, 1941 2 Sheets-Sheet 2 Patented a. 27, 1942 UNITED STATES PATENT OFFICER 2,300,343 2 nors'rnvo. MECHANISM Murray G. Clay, Chicago, Ill. Application January 24, 1941, Serial No. 375,319

7 Claims.

The invention relates to h'oisting apparatus.

One object of the invention is to provide hoisting mechanism which includes an electric motor for hoisting heavy loads through a speed-reducing unit and an auxiliary motor for operating the unit at higher speeds for quickly shifting light loads.

Another object of the invention is toprovide hoisting mechanism of this type with unitary control means whereby both motors may be controlled for hoisting heavy andlight loads at relatively low and high speeds.

Other objects of the invention will appear from the detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

In the drawings: Fig. 1 is a plan view of hoisting mechanism embodying the invention. Fig. 2 is a section taken on line 2-2 of Fig. 1. Fig. 3 is a diagrammatic view illustrating the hoisting mechanism and the electrical connections for controlling the operation of the motors. Fig. 4 is a longitudinalsection of the speed-reducing unit which is adapted to be operated by the motor for lifting heavy loads at low speeds and by both of the motors for lifting light loads at high speeds.

The invention is exemplified in hoisting mechanism which comprises a trolley-frame provided with wheels l9 adapted to run on the overhead tracks of a crane; a drum 2| for winding and unwinding a cable 22 for raising and lowering loads; a reversible variable speed three-phase electric motor a which is adapted to develop suflic ient horse power to operate the drum 2| for lifting and lowering heavy loads; a speed-reducing unit f ofthe helio-centric type; a power input shaft 23'fixedly connected to the rotor of motor a and journaled in a, bearing 28; a power outputshaft 24 journaled in a bearing 28 and coaxial with shaft 23; a pinion 25 on and driven by the output shaft; and a gear 26 fixed todrum 2| and meshing with pinion 25. The speed-reducing gearing f comprises a gear-case 21; an eccentric 29 integral with the input shaft 23; a ring 30 journaled on eccentric 29; an externally toothed gear 3| integral with ring 30; an internally toothed ring gear 32 fixed to gear-case 27, and with which eccentric gear 3| meshes; an, internally toothed eccentric gear 33 integral with ring 30; and an externally toothed gear 34 which is fixed to or integral with the output shaft 24. When gear-case 21 is stationary, motor a will moving heavy loads.

drive eccentric 29 to rotate ring 30 by reason of the engagement of the internal gear 32 and gear 3|, and ring .30 will drive gear 33 to rotate gear 34 and the output shaft 24 at a low ratio for Motor a is adapted for operation at different predetermined speeds for driving the helio-centric speed-reducing gearing to operate the shifting cable 22 through drum 2| for moving heavy loads at corresponding predetermined speeds. be of 35 horse-power and adapted for operation at 225,450, 900 and 1800 R. P. M, to drive the input shaft 23 at corresponding speeds for lifting heavy loads, such as 15 tons, and the shaft 23 will drive'the output shaft 24 through the gearing in the case 21 while the case is stationary, at corresponding low speeds. This motor a and gearing are designed, for example, forlifting .maximum loads of 15 tons so that when motor a is driven at its lowest speed of 225R. P. M. it will develop approximately 4% horse-power and drive the output shaft 24 at 3% R, P. M. to operate the cable 22 at the rate of 3% feet per minute; when driven at the second speed of 450 R. P. M., the motor will-develop 8% horse-power to drive the output shaft 24 at 6 R, P. M. to operate the cable 22 at the rate of 7 /2 feet per minute; when driven at its third speed of 900 R. P. M. the motor a will develop approximately 17%; horse-power and drive the output shaft 24 at 13 R. P. M. to

operate the cable 22 at the rate of 15 feet per minute; and when driven at its maximum speed of1800 R. P. M., motor a will develop approximately 35 horse-power and drive output shaft 24 at 26 R. P. M. to operate the cable 22 at the rate of 30 feet per minute. This exemplifies gearing for lifting heavy loads at relatively slow speeds. A spring-set magnetically releasable brake a,

which is released whenever the stator of motor a is energized, is provided for shaft 23 of said motor.

This brake, as well understood in the art, is set is cut off from said"- to hold the load when current motor.

When an empty hook or light loads, forexe, ample a load Weighing one ton, is. suspended.

from cable 22, it is desirable to expeditet theoutput shaft 24 relatively to the speed of the For example, motor a may input shaft 23 when the gear-case is rotated. A reversible variable speed auxiliary electric motor b is providedfor rotating the gear-case 2'! when it is desired to move the loads at high speeds. This motor b may, for example, be of 5 horsepower and adapted to be driven at 900 and 1800 R. P, M. Motor b may be v rtical and its case is supported by a standard 38 which is secured to frame 20 of the trolley. The rotor of motor b is connected by a sliding coupling b to a shaft 40 which is journaled in bearings 4| and 42 are mounted in standard 38. A worm 43 is keyed to shaft 40 and meshes with a gear 44 which is keyed on the outside of gear-case 21 for driving said gear-case from motor b. When lifting heavy loads, motor I) will be idle and gearcase 21 will be held stationary by worm 43 and gear 44. When auxiliary motor b is operated which while motor a is operated, it will rotate the gearcase 21 and the internal gear 32 and thereby increase the speed-ratio of gear-ring 30 relatively to the input shaft 23. For example, when motor a is operated at its maximum speed of 1800 R. P. M. and auxiliary motor b is operated at a speed of 900 R. P. M., the speed of the output shaft 24 will be increased to approximately '15 R. P. M. to operate the cable 22 at the rate of 90 feet per minute. When motor a is driven at its maximum speed of 1800 R. P. M. and the motor b is driven at its maximum speed of 1800 R. P. M., the output shaft 24 will be driven at 150 R. P. M. and cause the cable 22 to travel at the rate of approximately 150 feet per minute.

Motor b is provided with a spring-set releasable brake b of a construction well understood in the art, which is released whenever the stator of said motor is energized, and holds the load thereon when current is cut off from the motor.

The outer members of ball-bearings 4|, 42 for worm-shaft 35 are slidable in the support 38. A thrust-bearing 45 is provided at the lower end of shaft 35. The stationary member of thrustbearing 45 is engaged by a spring 46 and is adapted to engage an abutment 41 on support 38 when the worm 43 is subjected to downward thrust of sufficient magnitude to overcome said spring caused by the load on the gear-case 21. The force of spring 46 is adjustable by means of a screw 48. The spring 46 resists the downward thrust on worm 43 and shaft 35 which results from the load on the gear-case 21 and worm-gear 44 until bearing 45 engages the abutment 41. An over-load switch 65 is provided for interrupting the circuit through motor 17, in the event that a load in excess of a predetermined maximum is applied to the gear-case 21 while said motor is being operated. A pin 60 is slidably mounted in the housing or support 38 and is shiftable by thrust-bearing 45. Pin 60 is adapted to shift a switch-lever 62 which is fulcrumed at 63 and carries contacts for opening and closing switch 65 which is included in the circuit for motor b. Switch 65 is held normally closed by a spring 64 applied to lever 62. When the load on gear-case 21 is suflicient to force worm 43 and thrust-bearing 45 downwardly against the force of spring 46, hearing 45 will shift pin 60 and automatically open switch 65 to open the circuit for motor b and cause it to stop. When the load on gear-case 21 is reduced sufliciently to permit spring 46 to lift bearing 45, spring 64 will automatically shift lever 62 to close switch 65 and close the circuit for motor b at said switch.

Electrical equipment, illustrated in Fig. 3, is provided for controlling the operation of motors a and b for handling heavy and light loads at different speeds and for operating the motors in opposite directions for lifting and lowering. This equipment includes a relay 0 for controlling the direction of motors a and b; a relay d for controlling the starting and the operation at two speeds of auxiliary motor b; and a manuually operable switch-mechanism e for controlling the circuits-for relay 0 and the circuits for the relay d.

The rela 0 comprises an electromagnet c', which controls a set of three contacts 0 and an electromagnet c which controls a set of contacts c Conductors a a and a are connected to the stator of motor a and, when connected to the three conductors of input line a through contacts 0 will supply current to said motor for operating it in one direction and, when connected to line 9 through contacts 0 will supply current to the stator of motor a for the operation of said motor in the reverse direction.

Relay d comprises an electromagnet d for controlling a set of three contacts d and an electromagnet d for controlling a set of contacts a. Contacts (1 and d* are adapted to close circuits for supplying current from conductors a a and 11*, respectively, to the stator of motor b for operating said motor at predetermined low and high speeds. When contacts d. are closed and contacts 11* are open, current'will be supplied for the operation of motor b at a predetermined low speed. When contacts (1 are closed and contcasts d are open, current will be supplied to the stator of motor b for the operation of said motor at a high predetermined speed. Contacts 11 and d are connected to conductors a a and a which are controlled by the contacts c, c of relay c, so that auxiliary motor b will, at all-times, be operated in a corresponding direction to motor a. for the conjoint operation of gear-unit f by both motors. The switching mechanism e comprises a four-armed rotatable switch-lever e, which is provided with a handle e', whereby it may be manually rotated. One of the arms is adapted to control the operation of magnets c, c to control the stator-circuits for operating motor a in one direction for lifting and in the opposite direction for lowering loads. Three of the arms of lever e are provided with contacts e e and c respectively, which are connected by suitable conductors to the rotor of motor a for establishing circuits for controlling the speed of motor a.

One arm of lever e is provided with a contact e, which is connected by conductors 50,. M to one of the conductors of the input line a, for controlling the circuits through magnet c', c for starting motor a and controlling the direction of its operation for lifting or lowering. Contact .e on lever e is connected by conductor 5| to one of the conductors of the input line a. Contact e is engageable with an arcuate contact o when the lever is shifted to any of its six lifting stations and engageable with an arcuate contact e when lever e is in any of its six lowering stations. A conductor 52 connects contact 0 to the helix of magnet c for establishing a circuit to energize said magnet to control the contacts for operating the motor a for lifting. .A conductor 53 is connected to the helix of magnet c for energizing said magnet to control the circuits to motor a for operation in the reverse direction or for lowering.

Contacts e e e on lever e are engageable, respectively, with three sets of contacts e at six lifting stations for controlling the rotor-circuits and the speed of motor a in lifting when the lever is shifted in clockwise direction from its normal position, illustrated in Fig. 3, and are also engageable, respectively, with three sets of contacts e for controlling the speed and reverse operation of the motor a at six lowering stations when lever e is shifted from its'normal position in anti-clockwise direction.

' Resistors e are included in the conductors which are connected to contactse e at the first three lifting and the first three lowering stations of levers e -When lever e is shifted 'to the first station, either for raising or lowering,

all three of the resistors will be included in the rotor-circuits for motor a, so that the motor a will be operated at its lowest predetermined speed. When lever e is shifted to either lowering or raising station two, one of the resistors e will be excluded from the rotor-circuits for motor a and the motor will be operated at the second predetermined speed. When lever e is shifted to either raising or lowering station three,-two of the resistors will be excluded and the motor a will be operated at the third predetermined speed.. When lever e is shifted to either raising or lowering station four, all of the resistors will be excluded and the motor a will be operated at its maximum speed. The maximum speed will be retained at lifting and lowering stations five and six.

. stations, commencing Switch-mechanism e also includes means for controlling the operation of auxiliary motor b through lever e and handle e, so that the operator may manually control the operation and speed of motor b and the operation and speed of motor a. The circuits for the operation of auxiliary motor b are controlled by the arm of lever e which carries contacts e An additional contact e on said arm and connected to contact a by conductor 50, is provided for establishing circuits for energizing magnets d, d of relay d.

When lever e is at lifting station five, levercontact e engages a stationary contact e which is connected. by a conductor 54 to the helix of magnet 11', for closing contacts d to establish circuits for the low-speed operation of motor b when lifting loads. When lever e is at lifting station six, contact e engages a stationary contact e which is connected by a conductor 55 to the helix of magnet d for establishing circuits for the high-speed operation of motor b during lifting operations. At lowering station five, levercontact a" engages a stationary contact e for closing a circuit for energizing magnet 11' for the low-speed operation of motor b when lowering loads. At lowering station six, contact e engages a stationary contact e to close a circuit for energizing magnet 01 to close contacts 11 for the high-speed operation of motor b when lowering loads. A conductor 56 connects the helices of magnets d and d to the conductor a*. Overload switch 65 is included in conductor 56 so that when said switch is opened by an excessive load on the gear-case 21, the circuits through the helices of magnets d, 11 will be interrupted to open contacts d and d in the circuits for motor b and cause the latter to stop. The helix (1 for the brake a is connected to conductors a a The helix W of the magnetic brake b for aux- 'iliary motor b is connected to two of the contacts d.

The operation will e isin its neutral position, as illustrated in Fig. 3, the circuits for motors a and b will be open and motors a and b will be idle. When a heavy load is to be lifted, lever e will be shifted to engage the contacts at stations one, two, three or four, according to the speed of travel of the cable 22 desired in lifting the load. At any of said with lifting station one, a circuit will be established from one of the line conductors 9 through conductor 5|, contacts e, e, conductor 52 and the helix of magnet c. Said magnet will circuits from the conductors of the input lines a to the stator of motor a and cause it to be started and operated for lifting. The speed will progressively increase as lever c is shifted from stations one to four, as the resistors e are shortcircuited, as hereinbefore described. The drum 2| will be driven entirely by motor a. through the speed-reducing gearing f while motor b and the gear-case 2T remain'stationary. The speed of motor a is progressively increased to increase the lifting rate of travel of 7% to 15 to 30 feet per minute.

When the lever e is moved to engage any of the contacts e at the first four lowering stations, contacts e on lever e will engage contact e and establish a circuit through conductor 5|, contacts e net 0 and'one of the conductors g. Said magnet will be energized and shift contacts 0 to close circuits through conductors a a and a between the stator of motor a and the power input conductors g for the reverse rotation of the motor a for lowering heavy loads. The speed will be progressively increased between stations one and four, the sameas i lifting. At fifth and sixth lifting and lowering stations, the circuits for the operation of motor a at its maximum speed will remain the same as at station four.

When light loads are being lifted, it is desirable to shift them at a greater speed than those at which the input shaft 24 motor a at its maximum speed (1800 R. P. M.) and the speed reduction gearing f. Lever e will then be moved onto the fifth lifting station to cause the auxiliary motor b to be operated so it will rotate the gear-case 21 while motor a is running at its maximum speed. On the fifth lifting station, contact e on lever e will engage contact e and establish a circuit through con ductor 5|, contacts e e conductor 54, the helix of magnet d, and conductor 56. Magnet d will shift contacts d to connectthe low speed winding of motor b to the conductors a a a and cause said motor to operate at the lowest of its predetermined speeds, for example 900 R. P. M. This will cause the cable to travel in lifting at an increased speed of approximately .90

feet per minute, by driving the gear-case 21 of the unit 1 to correspondingly increase the speed of the output shaft 24. If it is desired to further increase the rate of travel of the lifting cabe as follows: When leverthen shift contacts 0 to close the cable 22 from 3% tov e conductor 53, the helix of magis driven solely by fifth and sixth lowering stations, lever e and contact e will similarly establish circuits through magnets d, (F, respectively, to shift contacts 11, (1*, respectively, for operating the motor b in the reverse direction at corresponding predetermined speeds to operate the cable 22 at 90 and 150 feet per minute, respectively, when lowering the loads. Contacts d and d for controlling motor b are connected to conductors a a and 0. The current in said conductors for operating the motor a in opposite directions, is controlled by the relay 0 so that the current supplied to-motor b from said conductors will operate auxiliary motor b for raising or lowering correspondingly to the direction of the operation of motor a.

In the event that the operator attempts to lift or lower a load which is too heavy to be handled by the auxiliary motor b, sufficient torque will be applied to gear-case 21 to cause worm-gear 44 to force worm l3 axially downward against the force of spring 46, until thrust-bearing 45 engages abutment 41. Thrust-bearing 45 will then hold pin 60 in position to open switch 65.

The magnets d, (1 will not then be energized, and contacts d, d will remain open, so that motor b will fail to start. The magnetic brake b will remain applied to, and lock motor b. When the controller-lever e is at the fifth or sixth stations, the hoist will be operated at the high speed resulting from the operation of both motors a and 11 only if the load is within the capacity of the auxiliary motor and when the load is excessive it will be handled by motor a at its maximum speed, which will operate the hoist at a lower speed than when motor I) is operated. If, at any time, the load decreases sufllciently so that the capacity of motor b is suflicient for the load, switch 65 will be automatically closed and the load will be shifted at the higher rate of travel effected by the operation of both motors d and b. By adjustment of the screw 48, the overload at which switch 65 is opened to render motor b inoperative, may be regulated as desired.

The invention exemplifies hoisting mechanism which comprises a main reversible variable speed motor for operating the gear-unit for lifting heavy loads and an auxiliary electric motor for operating the gear-unit while it is also being operated by the main motor, to increase the speed of travel of the hoisting cable above the maximum at which it may be operated by the main motor. The invention also exemplifies hoisting mechanism embodying a speed reduction gearunit and a pair of motors for operating heavy loads at low speeds and an auxiliary motor for hoisting the loads at comparatively higher speeds, and means for automatically preventing high- Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:

1. The combination with a hoisting drum and a cable which is adapted to be coupled to varying loads, of a gearing unit comprising an output shaft connected to drive the drum, an input shaft, hello-centric gearing between the shafts for driving the output shaft from the input shaft at reduced speed, and a rotatable element connected to drive the output shaft at a substantially higher speed than it can be driven by the reducing gearing, a variable speed electric motor connected to drive the input shaft and the output shaft and drum through the hello-centric gearing and of sufficient and suitable horsepower for hoisting heavy loads at suitable low speeds, a second electric motor connected to drive the rotatable element and output shaft of sustantially less horse-power than the other electric motor and suitable for. hoisting light loads at a higher speed than the speed used for heavy loads, and means for controlling the operation of the motors respectively for hoisting heavy and light loads on the cable.

2. The combination with a hoisting drum and a cable which is free, adapted to be coupled to varying loads of a gearing unit comprising an output shaft connected to drive the drum, an input shaft, reversible helio-centric gearing between the shafts for driving the output shaft from the input shaft at reduced speed, and a rotatable element connected to drive the output shaft at a substantially higher speed than it is driven by the reducing gearing, a variable speed reversible electric motor connected to drive the input shaft and the output shaft and drum through the hello-centric gearing and of sumcient horse-power for hoisting heavy loads at suitable low speeds, a reversible second electric motor connected to drive the rotatable element and output shaft, of substantially less horsepower than the other electric motor and suitable for hoisting light loads at a higher speed than the speed used for heavy loads, and means for controlling the operation of the motors respectively for raising and lowering heavy and light loads on the cable.

speed operation or the operation of the auxiliary a wide range of speeds and is economical in operation.

The invention is not to be understood as restricted to the details set forth, since these may be modified within the scope of the appended claims, without departing from the spirit and scope of the invention.

3. A combination with a drum and a cable which is adapted to be coupled to varying loads, of a gearing unit comprising an output shaft connected to drive the drum, an input shaft,'

speed-reducing gearing between the shafts for driving the output shaft from the input shaft at reduced speed, and a rotatable element connected to drive the output shaft at a higher speed than it is driven by reducing gearing, a variable speed electric motor connected to drive the input shaft and the output shaft and drum through the reducing gearing and of sufllcient and suitable horse-power for hoisting heavy loads at suitable low speeds, a second electric motor connected to drive the output shaft through the rotatable element at a higher speed than used for heavy loads, of substantially less horse-power than the othermotor and suitable for hoisting light loads at high speed, torque responsive means for stopping the second motor when the load on the cable is excessive for light loads, and means for controlling the operation of the mo- .tors respectively for hoisting heavy and light loads on the cable.

4. A combination with a drum and a cable which is adapted to be coupled to varying loads, of a gearing unit comprising an output shaft connected to drive the drum, an input shaft, helio-centric gearing between the shafts for driving the output shaft from the input shaft at reduced speed, and a rotatable element connected to drive the output shaft at a substantially higher speed than it is driven from. the input shaft, a variable speed electric motor connected to drive the input shaft and the output shaft and drum through the helio-centric gearing and of sufficient and suitable horse-power for hoisting heavy loads at suitable low speeds, a second electric motor connected to drive the rotatable element and output shaft, of substantially less horse-power than the other motor and suitable for hoisting light loads at a higher speed than that used for heavy loads, torque controlled means for stopping the second motor when the load on the cable is excessive for light loads, and means for controlling the operation of the motors respectively for hoisting heavy and light loads on the cable.

5. A combination with a hoisting drum and cable which is adapted to be coupled to varying loads, of a gearing unit comprising an output shaft connected to drive the drum, an input shaft, helio-centric gearing between the shafts for driving the output shaft at low speeds, and a rotatable gear-case connected to drive the output shaft without substantial speed reduction, a variable speed electric motor connected to drivethe input shaft and the output shaft and drum through the hello-centric gearing and of sufficient and suitable horse-power for hoisting heavy loads at suitable low speeds, a second electric motor, a worm and gear-drive between the second motor and the gear-case, said second motor being of substantially less horse-power than the other motor and suitable for lifting light loads at a higher speed than that used for heavy loads,

' and means for controlling the operation of the motors respectively for hoisting heavy and light loads on the cable.

6. A combination with a hoisting drum and cable which is adapted to be coupled to varying loads, of a searing unit comprising an output and the gear-case, said second motor being of substantially less horse-power than the other motor and suitable for lifting light loads at a higher speed than that used for heavy loads,

torque responsive means for stopping the second motor when the load on the cable is excessive,

7. A combination with a hoisting drum and cable which is adapted to be coupled to varying loads, of a gearing unit comprising an output shaft connected to drive the drum, an input shaft, hello-centric gearing between the shafts for driving the output shaft at low speeds, and

a rotatable gear-case connected to drive the output shaft without substantial speed reduction, a variable speed electric motor connected to drive the input shaft and the output shaft and drum through the hello-centric gearing and of sufficient and suitable horse-power for hoisting heavy loads at suitable low speeds, a second electric motor, a worm and gear-drive between the second motor and the gear-case, said second motor being of substantially less horse-power than the other motor and suitable for lifting light loads ata higher speed than that used for heavy loads, torque responsive means for stopping the second motor when the load on the cable is excessive,

and means for controlling the operation of the motors respectively for hoisting heavy and light loads on the cable.

MURRAY G. CLAY. I