US2351911A

US2351911A - Mine hoist control

Info

Publication number: US2351911A
Application number: US470283A
Authority: US
Inventors: James E Borland
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1942-12-26
Filing date: 1942-12-26
Publication date: 1944-06-20
Anticipated expiration: 1961-06-20

Description

June 20, 1944. J. E. BORLAND 2,351,911

' MIAINE HOIS'I' CONTROL Filed Dec. 26, 1942 INVENTOR 1/0/2765 5 Bar/017a! ATTORNEY Patented June 20, 1944 UNITED STATES PATENT OFFICE- MINE HOIST CONTROL James E. Borland, Wilkinsburg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application December 26, 1942, Serial No. 470,283

" Claims. (Cl. 254-473) My invention relates to a. system of control for motors and, more particularly, to direct curg rent motors for operating hoists.

In the operation of'mine hoists, many safety deyices are needed and among them are the brakes.

A more specific object of my invention is to positively require an attendant to release the brakes in a hoist equipment at the proper time to beable'to proceed with 'the hoisting opera-' tion. Y

Another object'of my invention is to deenergize both the motor and generator fields in a Ward-Leonard type of control'if the motor armature is prevented 'fromrotatin'g as by means of abrake. l

The objects specifically stated are merely illustrative. no doubt, become more'apparent from a study of the following specification and the drawing made part thereof.

In the drawing, the single figure is a diagram"- matic showing of my contribution to the art as applied to amine hoist.

In the figure, P designates 'a prime mover for operating a generator G and exciter E. The generator G and the exciterare disposed to supply energy to the hoist 'mot'or M.v The hoist motor is shown coupled to a pair of hoist drums operating loads such that'o'ne load moves up when another load moves down.

A suitable braking system B is provided forthe hoist drums 3'! and 38 and all theusual safety equipment .and control equipment is used.

I show only so much "of this equipment as is helpful in presentation of my invention. The best understanding of my contribution to the art may no doubt, be had from a study of the operation of the control.

Theoperation will be apparent from the following:

In the drawing. the equipment is shown not in operation. If the hoist is to be operated, the prime mover P is started and switches S, and

Many other objects and advantages will,

shown, are operated to closed position. The hoist motor M is thus connected to the main generator G.

.The controller C must be in the. ofi position, as shown, otherwise,.no operation of the hoist can be effected. This is one feature of my, invention, the importance of which will appear later.

When the speed of the prime mover P is up to full value, the voltage of the exciter E will be normal and as a consequence a circuit is established from bus I, through segments 2 and 3 of the controller C, switches 4 and 5, the coil 1 ii of the time limit relay 1, the back contactors other switches no part of this invention and not Band 9 of the directional contactors l0 and H to bus l2.

The time limit relay immediately closes its contact members l3 whereupon a circuit is established from the energized switch 5 through the safety equipment, closed contact member [3 of the time limit relay 1, through the parallelly connected coils l4 and I5 of the low voltage relay l6 and brake control contactor l1, respectively, to bus I2.

The low voltage relay closes its contact mem-.'

hers I 8 to hold itself in regardless of the position of the controller C. The operation of control contactor l1 closes the contact members 19 and 20. Closure of contact members I9 closes an energizing circuit, from the energized safety equipment to bus l2, for coil 2| of the field contactor FC. An instant later contact members 22 and 23 are closed to thus energize the motor field 24. Since contact members 20 are already closed, the parallelly connected brake release coils 25 and 26 are energized and valves 21 and 28 are thus closed. The circuit for these coils 25 and 26 maybe traced from bus I through contact members 22, and 20, coils 25 and 26, contact members 23 to bus l2.

By the closure of valves 21 and 28, the conduit connection through these valves from the region below the brake setting weights W1 and W2 to the low pressure side'of the hydraulic, or:

pneumatic, brake system B, is closed. It is now possible to release the brakes by the normal operation of the brake release levers 29 and 30.

Many hoisting operations require that power he applied to the hoist motor for a short period at the start of each hoisting cycle, before releasingthe brakes holding the cable winding drums. This has the advantage thatv the load at no instant starts to'descend just before it is to be hoisted. For those applications where this meth-' 0d of starting is not necessary, the brake levers 29 and 30 may be set to release the brake, without changes, before the controller C is operated to an operating position.

Assuming that the motor M is to apply a hoisting torque before the brakes are released, then 29 and 30, clockwise and counter-clockwise re-- spectively, supplies fluid pressure below the weights W1 and W2 to raise these weights,

whereby the brakes on the drums are released. Since the motor is alreadyexerti'ng a hoisting torque, the load is immediately picked up and the hoisting proceeds.

The time limit relay 1- has a time constant of several seconds. The time of its operation is adjustable by the spring means shown or in some other manner. Any kind of adjustable time limit device may be used.

The instant directional contactor ID has operated contact members 8 open to deenergize coil 6. After a predetermined time interval contact members I3 open. If the brakes have been satisfactorily released during the period of the time limit relay, the switches 39 and 43 are closed and the hoisting proceeds as desired, but if the attendant delays the releasing of the brakes too long, the contact member I13 opens before switches 3-9 and 43 are closed and in consequence the low voltage relay 16 is deenergized to open contact member l8. All the control-circuits are thus deenergized. This means that the brakes remain set even though an instant too late the valves 4| and 42 are operated to supply fluid pressure to the region below the weights W1 and W2. This. is sobecause, valves 21 and 28 are. opened by the deenergization of coils 25 and 26 to release any fluid pressure that might tend to develop below the weights W1 and W2. This is an important contribution to the art. The attendants are'thus, by the characteristics of my equipment, trained to proceed with the requisite dispatch when a hoisting operation is to be effected. This contribution is by no means the only one nor the most: important. one.

In direct-current variable voltage mine hoist equipment, it sometimes happens that the hoist,

erator-hoist motor armature circuit, suiiicient to overheat the motor armature, which would remain at a standstill, or to distort the commutator, by local heating under the brushes, or both.

If during operation when the controller is in any one of its operating positions, whether hoisting or lowering, and one or the other or both the. brake levers are. not in proper position either or both of the switches 39 and 40 will be open and since the contact members I3 of the time limit relay are open the control circuits will be deenergized because the energizing circuits for (iii coils l4 and I5 are opened. The operator, or attendant, thus loses control and must reset the controller to the off position and start all over. If he still has not properly set the levers 29 and 30 and he proceeds to start the hoist equipment by moving the controller to one of its operating positions, the time limit relay will, by holding contact members l3 closed for a short time, merely permit the application for a short time of a torque on the motor. My invention thus does not permit of any operation that might damage the hoist motor.

The benefits of my invention are also obtained when only one drumis to be operated. If only drum 31 is to be operated, the attendant operates clutch lever 43 to declutch drum 38 from shaft 44 and to close switch 45. Now it is still necessary to properly position lever 29 before proper operation of drum 31 may proceed.

The same, of course, holds true if drum 38 only is to be used. In this case, clutch lever 46 is operated to declutch drum 3'! from shaft 44- and switch 41 is closed. Now lever must. be in the correct position before the operation may proceed properly. If the equipment is of the type using only one drum fixed to the shaft then the clutch switches are not needed and only one brake lever switchis needed. The circuit needed would be one equivalent to an open circuit at switches 45 and 41 and a. closed circuit at switch 39, when the switch represents the one controlled by the single brake lever.

From the foregoing it will be apparent that I have thus provided a substantially fool-proof control scheme-but I do not wish to be limited to the particular showing made but wish to be limited only by the claims hereto appended.

I claim as my invention:

1. In a control for a hoist, in combination, a

effecting release of the brake, a normally open,

brake lever switch that is closed. only when the brake lever is actuated to release the brake, adirectional contactor for causing the operationof the motor in a given direction, back contact members normally closed when the directional contactor is not actuated, said contact members being connected in parallel to the brake lever switch, a controller having an off position and a plurality of operating positions, electromagnetic motor stopping means connected in series with the parallel circuit of said back contact members and brake lever switch whereby either the back contact members or the brake lever switch must be closed to energize said electromagnetic means,

said controller having switching means closed in the 01? position to energize said electromagnetic means and having switching means for energizing said directional contactor to open its backcontact members when in any one of its operating positions, whereby said electromagnetic means is deenergized unless the brake lever" switch is. closed when said controller is in its operating positions.

2. In a control for a hoist, in combination, a hoist drum, a motor for operating the drum, braking means for, as desired, either holding the drum or releasing it, a brake lever for effecting, when in one position, release of the brake, and when in a second position, setting of the brake, brake lever switching means closed when the lever is in its said one position and open when it is in its said second position, a contactor when energized causing the motor to operate, said con-T tactor having back contact'members, that arenormally closed when thecontactoris deener-. gized, said back contact members'beingzconnectedin parallel tothe brake lever switching means, electric means whichf-when deenergized, effect the stopping of said motor, saidelectric means being connected in series with the parallelly connected back contact members and brake lever switching means, whereby said electric means become deenergized if both the brake le'ver'switching means and contact members are open, a controller having an off position andan onoper'ating position for energizing said electric means, said controller effecting the energization of said contactor only in said operating positionwhereby the back contact members are opened, the function thus being, if the brake lever switching" means are not closed, to deenergize said electric means to thus deenergize the m'otor.

v 3. In a control for a hoist, in oombinat iom a' hoist drum, a motor for operating the drum; braking means for, as desired, either holding the drum or releasing it, a brake leve'rfor efiect ing, when in one position, release of the brake,

and when in a second position, setting of the brake, brake lever switching means closed when the lever is in its said' one" position and open when it is in its said-second position, a contactor when energized causing the motor to operate, said contactor having back contact'members that are normally closed when the contactor is deener gized, said back contact members being connected in parallel to the brake'iever 'switching means,

electric means which, when deenergized, effect the stopping of said motor, saidelectric means being connected in series with the parallelly" connected back contact members and the brake lever switching means; whereby said electric means become deenergi'z'ed when both the brake lever switching means and the contact members are open, a clutch for disconnecting the drum from the motorya clutch lever, cliitch lever switching means'closed when said drum, is ,de-,

clutched from themotor, said clutch switching means being disposed in parallel to the ba(':k.contact members and brake lever-f switching means,

a controller having an off position and an oper ating position for energizing said electric means, said controller effecting its energization of said contactor only in said operating position whereby the back contact members are opened, the fnnction thus being, if the brake leverswitching means and the clutch lever switching means ,are: both open. to deenergizesaid electric means to stop the motor. or to operate the motor independently of the brake lever switching means if the clutch lever switching means is closed.

4. In a control for a hoist, in combination, hoist drum, a motor for operating the drum,, 0 braking means for, as desired, either holdingthe drum or releasing it, a brake lever for ,eifecting,

when in one position, release Ofthebrake, and. .when in a second position, setting of, the brake,

brake lever switching meansclosed when the lever is in its said one position, and open whenit is in its said second position, a contactorwhen energized causing the motor. to operate; said contactor having back contact members that are normally closed when the contactor is deenergized, said back contact members being connected in parallel to the brake lever switching means,-; electric means which,'when deenergized, effect the stopping of said motor, said electric means beingconnected in series with the parallelly, connected back contact members and brake lever switching.

means, whereby said electric means become deenergized if both the brake lever switching means and contact members are open, a time limit de'-' vice having switching means that remain closed fora short time after the time limit means hecomes deenergized, said time limit switching means being disposed in parallel to the back contact members and brake lever switching means whereby said electric means remain'ern' ergized 'for a short time even though both said back contact members and brake lever switching means are opened, a controller having an 01f position and an operating position for energizing said electric means, said "controller" effecting the energization of 'said contactor and the deenergization of said time limit device only in said operating position whereby the back contact members and a short time thereafterthe time limit switching means are opened, the function thus being, if the brake lever switching means are not closed prior to the end of the short time, to deenergize said electric means to thus deenergize the motor.

5. In a control for a hoist, in combination, a hoist 'drum, a motor for opera-ting the drum, braking means for, as desired, either holding the drum or releasing it, a brake lever for effecting, when in one position, release of the brake, and when in a second position, setting of the brake,

electric means which, when deenergized, effect the stopping of said motor, said electric means being connected in series with the parallelly con nected back contact membersand the brake lever switching means, whereby said electric means become deenergized when both the brake lever switching means andthe contact members are open, a'clutch for disconnecting the drum from the motor, a clutch lever, clutch lever switching means closed when said drum is declutched from the motor, said clutch switching means being disposed in parallel to the back contact members and brake lever switching means, a time. limit device having switchingmeans disposed in par-' allel to the back contact members, the brake lever switching. means, and the clutch lever switching means, and operable to remain closed for ashort timeafter the time limit device becomes deenergized, whereby said electric means remains energizd for a short time if all the other switching means ofthe mentioned parallel connections are open, a controller having an oif position and an operating position for energizing said electric means, said controller'efiecting the energization of said'co'ntactor'and' thede'energization of said" time limit device only in said-operating position whereby the back contact members are opened and a short time 7% thereafter the time limit switching means is opened, the function thus b'eing, if the brake lever switching means and the clutch-lever switching means are both open, to deenergize said electric means to stop the motor attheend of the short time, or to operate the" motor independently of thebrake lever switching'meansif the clutch lever switching means is closed; 1

6'. In a system of: control for a hoist, in combination, a motor, a hoist drum operated by the motor; a brake, a brake lever for efiecting the release and setting of the brake depending-on the position of the brake lever, a controller operable, when not in its off position, to energize the motor, a source of supply, a control circuit connected to the source of supply, said circuit including, a controller switch, closed only when the controller is in the oil position, and an electromagnetic coil operated switch, closed only when the coil is energized, said controller switch and electromagnetic coil operated switch being connected in parallel with each other and inseries with the coil of the coil operated switch, and a controller operated switch, closed only when the controller is in the oil. position, and a brake lever switch, closed only when the brakeis released,.. said controller operated switch and brake lever-switch being connected in parallelwith each other and also connected in series.

with the coil of the coil operated switch, said circuit also including, switching means for stopping the energization of the motor when the coil of the coil operated switch becomes deenergized.

'7. In a system of control for a hoist, in combination, a suitably operated generator, having a generator field winding, a motor, having a motor field winding, connected to the generator to be operated thereby, a hoist drum, operated by said motor, a brake, a brake lever for setting the brake to hold the drum or release it depend-- ingon the position of thebralre lever, a source of direct current power, an electromagneticallyat least one operating position, a control con tactor having an actuating-coil and contact members that are closed only when the actuating coil is energized. switching means, connected in parallel with said contact members, and thus comprising a first parallel circuit, said switching means being controlled by the controller and in closed circuit condition only when the controller is in the off position, a second parallel circuit comprising second switching means, and a brake lever switch, connected inparallel, said second switching means being subject to the control of i said controller and being closed only when said controller. is in the off position, said brake lever switch being closed only when the brake lever is in position to release the brake, said actuating coil. of the control contactor and said two parallel circuits all being connected in series to said source of direct current, and means responsiveto the opening of the contact members of the control contactor for deenergizing said electromagnetically operable'switch,

8. In a system of control fora hoist, in combination a suitably operated generator, having a generator field winding, a motor having a motor field winding connected. to-the generator to be operated thereby, a hoist drum, a clutch and lever therefor, which lever, when in one position, clutching the drum to the motor shaft to thus be operated thereb and when in another position declutching the drum from the shaft, a brake,

a brake lever for setting the brake to hold theassgerr drum or release. it depending on the position of the; brake lever, a source of direct current power,

an: electromagneticallyoperable switch for connectingthe source of power to the motor and generator field windings when the electromagnet of the electromagnetically operable switch is energized and for disconnecting the motor and generator field windings when said electromagnet is deenergized, control circuits disposed to be connected to the source of direct current, said conallel circuit comprising second switching means,

a brake lever switch, and a clutch lever switch connected in parallel, said second switching means being subject to the control of said controller and being closed only when said controller is in the ofi position, said brakelever switch being closed only when the brake lever is in position to release the brake and said clutch lever switch being closed only when the clutch lever is in a position to declutch the hoist drum from the motor shaft, said actuating coil of the control contactor and said two parallel circuits,

all being connected in series to said source of direct current, and means responsive to the opening of the contact members of the control contactor for deenergizing said electromagnetically operable switch.

9. In a system of control for a hoist, in combination, a suitably operated generator, having a, generator field winding, 2, motor, having a motor field winding, connected to the generator to be operated thereby, a hoist drum, a brake, a brake lever for setting the brake to hold the drum or release it depending on the position of the brake lever, a second brake, a second hoist drum, a second brake lever for setting the brake to hold the second hoist drum or release it depending on the position of the second brake lever, a source of direct current power, an electromagnetically operable switch for connecting the source of power to the motor and generator field windings when the electromagnet of the electromagnetically operable switch is energized and for disconnecting the motor and generator field windings when said electromagnet is deenergized, controlcircuits disposed to be connected to the source of direct current, said control circuits including, a controller having an ofi'position and at least one operating position, a control contactor having an actuating coil and contact members that are closed only when the actuating coil is energized, switching means, connected in parallel with said contact members, and thus comprising a first parallel circuit, said switching means being controlled by the controller and in closed circuit condition only when the controller is in the off position, a second parallel circuit comprising second switching means, and in parallel therewith, two series connected brake lever switches coupled to the respective brake levers, said second switching means being subject to the control of the controller and being closed only in brake releasing positions, said actuating coil of said control contactor and said two parallel circuits all being connected in series to said source of direct current, and means responsive to the opening of the contact members of the control contactor for deenergizing said electromagnetically operable switch.

10. In a system of control for a hoist, in combination, a suitably operated generator, having a generator field winding, a motor having a motor field winding connected to the generator to be operated thereby, a hoist drum, a clutch and lever therefor, which lever, when in one position, clutching the drum to the motor shaft to thus be operated thereby and when in another position declutching the drum from the shaft, a second hoist drum, a clutch and lever therefor, which lever, when in one position clutching the second drum to the motor shaft to thus be operated current power, an electromagnetically operable switch for connecting the source of power to the motor and generator field windings when the electromagnet of the electromagnetically operable switch is energized and for disconnecting the motor and generator field windings when said electromagnet is deenergized, control circuits disposed to be connected to the source of direct current, said control circuits including, a controller having an off position and at least one operating position, a control contactor having an actuating coil and contact members that are closed only when the actuating coil is energized, switching means, connected in parallel with said contact members, and thus comprising a first parallel circuit, said switching means being controlled by the controller and in closed circuit condition only when the controller is in the off position, a secondparallel circuit comprising second switching means, and connected in parallel therewith one sub-parallel circuit including a brake lever switch coupled to the first brake lever and a clutch lever switch coupled to the first clutch lever, and a second sub-parallel circuit including a second brake lever switch coupled to the second brake lever and a second clutch lever switch coupled to the second clutch lever, said second switching means being subject to the controller and being closed only when the controller is in the ofi position, and said brake lever switches and clutch lever switches being closed only when the respective levers to which they are coupled are in positions respectively to release the brakes and declutch the drums, said actuating coil of said control contactor and said first and second parallel circuits all being connected in series to said source of direct current, and means responsive to the opening of the contact members of said I control contactor for deenergizing said electroswitch.