US1219761A

US1219761A - System of control.

Info

Publication number: US1219761A
Application number: US69610712A
Authority: US
Inventors: Ray C Newhouse
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1912-05-09
Filing date: 1912-05-09
Publication date: 1917-03-20
Anticipated expiration: 1934-03-20

Description

R. C. NEWHOUSE.

SYSTEM OF CONTROL.

APPLICATION FILED MAY 9. 1912.

1 ,21 9,76 1 Patented Mar. 20, 1917.

. UNITED s A'rEs ara RAY c. NEWHOUSE, or MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO ALLIS-QHALMERS MANUFACTURING COMPANY, A CORPORATION OF DELAWARE.

- SYSTEM or common Toall whom it'may concern:

, Be it known that I, RAY C. NEWHousE, a citizen. of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certainnew and useful Improvements in Systems of Control, of which the following is a full,

clear, and exact specification.

My invention relates to electrically operated skip hoists.

It is the object of my invention to provide a skip hoist, for hoisting stone, coal, ore, etc., which is normally completely automatic in its operation but may be manually controlled when desired.

In attaining this object, have provided a system involving a number of novel features. The movement of theskips is preferably obtained by an electric motor, and the motor is controlled by'the closing of the gate of the bin from which the' material to be mally entirely automatic, the operator may at any time assume control and obtain any desired movement of the skips within-their limits of movement. There are'also pr'ovided a number of safety devices.

drawings, and will be vention; a

The two skips and 11 operate on the usual Y The various novel features ofmy invention will appear from thedescription and particularly pointed out in the. claims. p I

The single figure of the drawing shows diagrammatically one embodiment of my intrack's-12, these tracks 12 being arranged so that the skips pass each other without interferingand'yet each skin-when at the a bottom. of the hoist occupies substantially the? same place as does the other skip under the-seams circumstances.

cable or cables .13 extend inthe usual man- The operating her around the winding drum 14, and its ends are fastened to bails '15 pivoted to the skips near their rear ends, This manner of I Specification of Letters Patent.

Application filed May 9,1912. Serial No. 696,107.

-motor of the wound rotor type. .mary circuit is supplied from a three-phase The closing of the bin gate is also I manually controlled irrespective of the load in the skip. Although-the operation is norrammed Mar. 2o; 1917.

pivoting the bails 15 allows the automatic tipping of the skips .as they reach the top. To obtain this tipping, the rear axle of each skip is provided with additional wheels 17, which engage the auxiliary track 18 when the skip is at the top of the hoist. As a skip approaches the top, its front axle follows the curved upper end of the main track 12, whlle its rear axle follows the auxiliary track 18, the skip being thus automatically dumped; the skip 11 is shown dumping.

The hoisting drum 14 is operated by the motor 20, preferably being directly connected thereto. This motor may be of anv desired type, being shown as an induction Its pri line 21, through a circuit-breaker 22 and a reversing switch 23. The circuit-breaker 22- is'biased to open position, but is held in closed position by a latch 24. The latch in turn is biased to unlatching position, but 3 is held in latching position by a solenoid 25 located in a circuit which, under normal conditions, is always closed. The circuit of this solenoid may be called an'emergency con-- trol circuit. .Upon the deenergization of the solenoid 25, for any reason, the circuitbreaker 22 opens. The, reversing switch 23 is preferably of the oil immersed, doublethrow, 'Inultipole type, and is biased to open position. It is movable to its two closed positions by

solenoids

26 and 27 respectively.

may 'be short-circuited by switches 32, 33, 34,35, operated by solenoids 36, 37, 38, and

'39 respectively. The

solenoids

26, 27, 36,

37, 38, and 39 are'controlled by a manually operated master switch 40, aplurality of manually operated switches 41, a set of switches 42 to 45 inclusive, automatically actuated master direction switch 54, and a manually controlled reversing switch 46.

The master switch 40 is provided for man ually. starting and stopping the motor and skips In closing the switch, the blade 47 first-engages contact 48 for energizing

solenoids

26 and 27 for operating the switch 23 in one direction or the other. Upon further movement of the blade 47 inthe same direction,said blade comes into engagement with contact 49 for energizing solenoids 36, 37, 38, and 39 of the resistance Switches 32, 33,

.34, and 35 respectively. By opening the master switch 40, the blade leaves contacts master switch is to be located at some convenient point, such as at the mam operating stand.

' The manually operated switches 41 are located at various points in the control system. For instance, these switches may be located on different floors or at points of comparatively great distance from each other. These switches 41.are adapted, when switch 40 is closed, to start and stop the operation of the whole system in the same manner as it is accomplished by the opera.- tion of the master switch 40. The switches are here used primarily as emergency switches for shutting down the system from various points if it is desired so to do for any particular reason. The switches 41 each have two

movable contacts

41 and 41*, the first of which engages an elongated contact 41 so that when said switches are opened the sections of resistance controlled by the contact 41 will be cut into circuit before the main line circuit is opened by separating

contacts

41 and 41. It is to be noted,

. however, that only one such switch as 40 is .shaft a ratchet w to be used, while any number of switches 41 can be employed. The reason for this is apparent, for if two such switches as 40 were used, one could he opened and still the system would continue to operate, providing the one remaining, closed was on the live side of the open switch.

The switches 42 to 45 inclusive are biased to their lower positions, as by gravity, but may be raised to their upper positions by a taper-ended nut 58 traveling along a thread ed rod 59 driven through suitable reducing gearing from. the shaft, of the motor 20. Guides 58 prevent the nut 58 from turning. These switches are closed only in their lower pos1t1ons. The switches 42' and 45 in their lower positions are in the circuits of the solenolds 26 and 27 respectively. The

switches

42 and 43 are in circuit with ,the solenoids 36 to 39 inclusive when the motor is operatmg 1n one dlrection, and the switches 44 and 45 are in circuit with said solenoids when the motor is going in the opposite directlon. The switches 42 to 45 inclusive may be spaced as desired.

The master direct'on switch 54 has on its hieel 60, the number of teeth ofthe ratchet wheel corresponding to the number of positions of the switch 54.

This number is an even number, the switch in alternate positions closing the circuit of the

switches

42 and 43, and 44 and 45, respectively; thus oppositely controlling the direction of operation of the motor 20. The

switch 54 is operated automatically, through the ratchet Wheel 6Q, in a manner hereinafter described.

L My present. system is also provided with the double-throw switch 46- for the purpose of manually reversing the direction of operation at any time without regard to the'direction in which the system is operating or to the position of the skips. In other words, switch 46 when-thrown to the position opposite to the one in which it is found changes the connections of switch54 and switches 42 to 45 inclusive for controlling the actions of

solenoids

26 and 27 for reversing the motor 20. When switch 23 is operated,

auxiliary switches

26 and 27 are also operated for controlling the circuits of solenoids 36 to 39 inclusive of the resistance switches 32 to 35 inclusive. Thus the operation of the system may be manually reversed at will by merely throwing switch 46 to the position opposite to the one in which it is found.

The motor is provided with a mechanical brake 64, cooperating with a disk 65 on the shaft of the motor 20. The brake is released by a solenoid 66 whenever current is being supplied'to the motor 20, the solenoid 66 being connected to the motor circuit through a current transformer 67.

The automatic operation of the ratchet wheel 60 above referred to is obtained by a finger 68 hinged on the balance arm 69 of the gate 70 of the supply bin 71. The bin gate 70 is biased to closed position by an adjustable weight 72 on the balance arm 69. During the last part of the closing movement of the bin gate 70 the finger 68 strikes one of the teeth of the ratchet wheel 60 and moves the master direction switch 54 from one position tothe next. The bin gate 70 carries a pivoted'finge'r 73, which is in the path of an arm.74 on the top of each skip. The finger 73 is biased into the path of the arm 74 by a light spring 75 and most ofthe time is held there by a latch 76, which latter is connected by suitable connecting mechanism to the balance beam 77 of a scale upon which the skip at the bottom of the hoist rests and is,released uponsa. tion of said beam. The platform of this scale consists of two parallel plates 78 and 79, the

former being mounted on the other by a nest of springs 80. On the balance beam 77 is an adjustable weight 81 for determining nt deflec= the hoist. Immediately upon the opening of the bin gate, the stone, ore, or other material to be hoisted, begins to run from the bin 71 into the skip 10, which may be provided with a lip 82 to prevent any of the material from falling between the, gate and the skip. The circuit-breaker 22 is closed. The switch 23 is in its middle or oif position, the traveling nut is at the extremeleft hand limit of its movement, holding

switches

42 and 43 in their upper or open positions. The switches 45 and 46 are in their lower or closed positions. The resistance switches 32 to 35 inclusive are inthe lower oropen positions.

To make the system operate automatically at full speed the master switch 40, switches 41 and 46 should be closed, and there left while the uninterrupted automatic opera tion is to continue. As the-skiplO fills, the plate 78- of the scale platform is depressed, first compressing the springs 80 and then engaging and depressing the plate 79 of the scale platform and raising the weight 81. When the load in the skip 10 reaches a pre: determined value, the tilting of the balance beam 77 releases the latch 76, and the finger 73 momentarily swings past the arm 74 to allow the weight 72 to close the bin gate 70.

This shuts ofi' the supply of material to the skip 10. As the bin gate approaches its closed position, the finger 68 strikes one of the teeth of the ratchet wheel 60 and moves the master direction switch 54 forward to the next osition beyond that which it occupies. Th1s completes a control circuit which extends from one side of the control supply line 83 through contact 84'on the switch 54, conductor 85, reversing switch 46, conductor 86, switch 45,'conductor 87, solenoid 27 conductor 88, switches 41 and 40, to theother side of the line 83. The resultant energization of coil 27 closes the switch 23 to the left, and also causes the closing of the auxiliary switch 27 carried by the switch 23,

thus putting the resistance switches 32 to 35 inclusive under the control of the switch 44 and completing the primary circuit of the motor 20 for operation in one direction. The

completion of this primary circuit energizes solenoid 66 to release brake 64.

The motor 20 now starts slowly, driving the winding drum 14 and the rod 59; thus causing the skip 10 to-start upward, the skip 11 to start downward, and the traveling nut.

58 to startto the right. The hinged end of the finger 73, which finger has been brought b ack by the spring 75 into the path of-the arm 74 and is ree'ngaged by the latch 76 as soon as the skip 10 has started u ward, allows such arm to pass without e ect as the skip 10 rises. As the nut 58 moves to the right, it first allows the switch 42 to drop from it upper to its lower position, thus making a potential circuit for solenoid 26, which at this time is open at the switch 54. As the nut 58 continues its movement to the right, it allows the switch 43 to drop to its lower or closed position, thus making another potential circuit, through the switch 43, for the 1 solenoids 36 to 39 inclusive; this potential circuit is open at the switch 54 andat the auxiliary switch'26 also carried by switch 23. The droppingof the

switches

42 and 43 does not affect the speed of the motor 20.

1 As soon as the

switches

23 and 27 are closed to the lefta circuit is completed from one side of the control supply line 83 through contact 84 of switch 54, conductor 85, re-

versing switch 46, conductor 86, switch 45, conductor 87, branching from the circuit of solenoid 27 and continuing through auxiliary switch 27 conductor 50, switch 44, conductor 51, contact 35, conductor 100, switch section, 28, of the resistance in the rotor circuit of the motor 20. If, however, the auxiliary switch 28 has been opened, due to excess current in the secondary circuit when v the motor is first, started, switch 32 will not be closed until the current in' the secondary circuit has decreased sufliciently to permit said switch 28 to close. If, when switch 32 is closed,-the secondary current rises above a predetermined value, auxiliary switch 29 'will be opened, therebypreventing solenoid 37 from being energized. At this point it is to be noted that the contacts 102 with ,Which the resistance switch members 32,33, and 34 come into contact are elongated. This is for the purpose of completing the circuit-of the solenoid of the next auxiliary switch, such as-29 permitting said switch to be opened as 33. When switches 32 and 32 are closed v and 29 has remained closed or returned to closed position, the circuit of the solenoid 37 is completed, resulting in the closing of switch 33 and the cutting out of the second section, 29, of the resistance. Similarly switches 34 and 35 are closed in turn, successively cutting out the remaining sections 30 and 31 of resistance. This vbrings the motor 20 up to full'speed.

Such full speed continues until the skip 1O approaches its upper limit ofmovement and the skip 11 its lower limit of movement. At the same time, the traveling nut -58 approaches its right hand limit of movement.

The tapered end of nut 58 now raises switches 44 and 45 successively. The

lifting. of the switch 44 breaks the circuit for the solenoids 36 to 39 inclusive, thus deenergizing all solenoids which rema ned denergizes solenoid 27, thus causing the openin of auxiliary switch 27 and causing switch 23 to move to its middle or ofi position and interrupting the supply of current to motor 20 The interruption of this in supply of current causes the deenergization of the solenoid 66, and the setting of the brake 64.

The motor 20 and the two skips now stop, the skips 10.and 11 having now reached their upper and lower limits respectively. The skip 10. in approaching this upper limit has tipped to dumping position, the wheels on its front axle having followed the curve at the upper end of the main track 12 and the auxiliary wheels on its rear axle having followed the auxiliary track 18. The material is thus dumped from the skip into the receiving bin 89. The arm 74 of the skip 11, as the latter has approached its lower limit of movement, has engaged the finger 73 and swung the bin gate 70 to open position, whereupon the supply bin 71, unless empty, immediately begins to discharge material into the skip 11. When the skip 11 is filled with a predetermined load, the finger/73 is again released from the latch 76 and the bin gate 70 again swings closed. At the end of this closing movement, the finger 68 engages the next tooth of the ratchet wheel 60, and swings it and the master direction switch 54 forward to the next position. This brings the contact 90 of said switch into operation, and completes a circuit which extends from one side of the line 83 through contact 90 of switch 54, conductor 9l, reversing switch 46, conductor 104, switch 42, solenoid 26, conductor 88, switches 41 and 40 to the other side of the line 83. .The resultant energization of the. solenoid putting the solenoids 36 to 39 inclusive under the control of the switch 43, completmg the prlmary circuit 'of motor 20 for operatlon in the opposite direction from that above described, and releasing the brake 64.

The motor 20 now starts in such opposite direction, raising skip 11, lowering the skip 10, and moving thev traveling nut 58 to the v53 left. As this movement of the nut 58 continues swit ches 45 and 44 are dropped in succession and the resistance sections 28, 29',

26 causes switch 23 and aux-' 111ary switch 26 to close to the right, thus.

switches 44 and 45 as the nut 58 approached its right hand limit, as already described. The skip '10, which is now' approaching the bottom, opens the bin gate in the last part of its downward movement. From this point the cycle above described is repeated continuously as long as any material is left in the supply bin 71, then it automatically stops.

Considerable energy is required to start the movement of the skips, and considerable energy must be disposed of in order to stop such movement. The following scheme is provided to take care of this economically. Located between the rails of the'track 12 at the bottom is a hook 92, which can slide in suitable guide rails lengthwise of the track 12. This hook extends upward from the track into the path of some suitable projecting part of the skip, such as one of the axles or a hook 93 firmly fastened to the body of the skip. The sliding hook 92 is attached by a sturdy cable 94 to a circular sheave 95, the cable 94 extending over one or more pulleys 96 to a convenient location for such sheave 95. The circular sheave 95 is mounted on the same shaft or otherwise firmly connected to a spiral sheave 97, on the periphery of which is a cable 98 attached to a heavy weight 99. When either skip approaches the end of its downward movement, the hook 93 on such skip engages the sliding hook 92 and swings the cable 98 around the spiral sheave 97 thus raising the weight 99 and storing energy in it. Be-

cause of the spirality of the sheave 97, the

weight 99 is started on its downward movement comparatively slowly, and gradually increases in speed. In other words, the mechanical advantage of the skip on the weight is decreased as the weight moves upward. The weight thus assists in bringing the skip to a standstill, this action being effected because of the spiral sheave 97 without any violent jerks on the mechanism or any undue strains on the cables 94 and 98.

The energy stored in the lifted weight 99 is returned to the skip when the latter starts on its upward movement, thus releasing the motor 20 of some of its starting load. The rate at which this energy is returned to the skip is a gradually decreasing one, thus relieving the starting load on the motor 20 mostly at the beginning of the movement of the latter and gradually decreasing as the motor and skips gain in speed and the extra starting load diminishes.

If at any time during the operation of the system, the operator desires to take control, he mdy'do so by manipulating the master switch 40 or auxiliary switch 41. If the skipsare at their of movement,

and the traveling nut 58 is at one of itslimits of movement, the motor may be directions of movement, for, by the use of the reversing switch 46, the "movements of the skips may be stopped atany point in their upward and downward movements and reversed at will. If the motor is inmotion and it is desired to stop the skips, the master switch 40 is moved to off position, thus breaking the circuits for the solenoids 36, 37, 38, and 39, and

solenoid

26 or 27, whichever one is energized. This inter-' 'rupts all the normal control circuits and the resultant opening of the reversing switch 23 interrupts the primary circuit of the motor and causes the setting of brake 64.

- However, if it' is desired to stop the operation of the system at any timefor any rea son whatsoever, it is not necessary to be at the main operating stand to open the master switch 40, for the desired result may be accomplished by opening any one of the emergency switches 41. By opening any one of the switches 41 the cutting of the sections of resistance into the secondary circuit of the motor is first caused, and then the reversing switch 23 is caused to moveto its open position, cutting OK the current supply to the motor 20. When it is desired to again start up the system, switch 40, if it has been opened, maybe closed, blade 47 first coming into engagement with contact 48 for operating switch 23' to connect motor 20 to its supply circuit 21 and then blade 47 engaging blade 49 for caus- 'ing the gradual cutting out of sections of resistance from the secondary circuit of motor 20. If the master switch has remained closed and either one of the emergency switches has been opened, the emergency switch which has been opened may be closed, contact 41 of said switch first engaging the elongated contact 41 for closing the reversing switch 23 for connecting motor'20 to its'supply circuit, and thencontact 41 engaging its corresponding contact for causing the gradual cutting out of the sections of resistance in the rotor circuit of the motor 20. When once started the system will at once take up and continue the automatic operation already described,

the parts automatically stopping when they reach their limits of movement and starting again when the skip at the bottom becomes sufliciently loaded. v

NVith the arrangement which I have here provided it is not necessary that the skip at the bottom becomes loaded to a predetermined amount before the bin gate can be closed with the resultant actuation of the master direction switch 54 for making connections for the skip at the bottom to move upward. If it is desired to close the bin gate 70 before the skip at the bottom has received its regular load of a certain predetermined weight, a push button 105 may be operated, completing a circuit from one side of the line 83 through push button switch 105, conductor 106, solenoid 107,,to the other side of the supply circuit 83. The resultant energization of coil 107 will draw core 108 with its lever 109 downwardly, removing the latch 7 6 out of engagement with the finger 73 of the bin gate, permitting weight 72 on the arm 69 to close the bin gate and move the master direction switch to its next forward position for causing the upward movement of the skip at the bottom and the downward movement of the skip located above.

The master switch 40, reversing switch 46, and'push button switch 105 are preferably located at the main operationstation where ton control switch 105 all located at the central point of operation, manual control at such point isrendered convenient, and with the emergency switches 41 located at different points in the system manual con- 'the operator may operate any of these trol is provided for bringing the system to a state of rest and for again starting said system when it is so desired. Should the parts already described get out of order' or fail to work for any reason, it is possible that the motor will overwind the cable 13 on the drum 14, which might even break the cable. In order to take care of this, a latch 112 is placed in the path of each of the bails 15 slightly beyond the normal upper limit of movement thereof. In case of overwinding,,the bail 15 strikes the latch 112 and mbves it in a counter-clockwise direction. This snaps open 4 the switch 113 in the emergency control circuit, which is that of the holding solenoid 25 of the circuit-breaker 22, thus causing the tripping of such circuit-breaker and the breaking of the circuit of the motor 20. This stops the motor. In order to prevent the skip at the top of the hoist from falling in case the cable has been broken by the overwind, the latch 112 at-once automatically swings back beneath the cross bars of the bail 15. If the skip starts to drop,

this latch will therefore catch the bail and prevent such dropping.

If the cable 13 breakswhile the system 'is m operation, both skips may fall to the bottom of the hoist, the first skip to reach the bottom wouldv open the bin gate 70 and would probably be traveling with so much momentum that due to the impact on the scale platform it would. raise the balance beam 77 sufficiently to open a snap switch 114. This switch 114 is also in the emergency control circuit, or that of the solenoid 2 5, and its opening produces the same results as those produced by the switch 113. The disposition of the switch-114 relative to the Weightedbeam 77 is such that ordinary operation of the beam due to the weight of a loaded skip, is not capable of causing actuation of the switch to open position. The nest of springs 80 is for the purpose of preventing the lesser impacts occurring in the ordinary operation of the system, from tripping the latch 76 and the switch 114, for absorbing the last of the momentum of a descending skip, and for giving an ascending skip a kick at starting.

Should the voltage of themain supply circuit 21 fail for any reason while the motor is in operation, the solenoid 66 is immediately decnergized. This causes the setting of the brake 64. If the voltage of the con trol and supply circuit 83 fails. for any reason while the motor is in operation, all of the control circuits will be denergized. This causes the resistance in the rotor circuit of the motor to be cut in, andthe primary circuit of the motor to be broken both at the reversing switch 23 and the circuitbreaker 22. c"

Any suitable protective means may be provided for protection against the overloads. In case of an overload in the arrangement illustrated, a series relay 115 opens the circuit of the solenoid 25 and thus causes the opening of the circuit-breaker 22. In some cases the circuit-breaker 22 may be dispensed with and .the switches 113, 114, and 115 put in some other suitable circuit.

Broad features of the invention described herein are claimed in my co-pending application Serial No; 633,798, filed June 17, 1911, which has matured into Patent No. 1,207,983, Dec. 12, 1916. Further, certain features relating to the operation and con- ,'.trol of the hoist system of'this application cation.

are introduced in my co-pending application Serial No. 123,788, filed Oct. 2, 1916, and my co-pend-ing application Serial No. 140,640, filed Jan. 2', 1917, the latter application being a division of the present appli I have described my hoisting system in what I now consider to be its preferred i form. There may be various modifications and arrangements other than those here particularly shown and descrrbed, and I aim to cover all such modifications and arrangegate to cause said ments of my invention which do not depart the material in the car for controlling the closing of the bin gate, and means operated by the closing of the bin gate for causing said power operated device to hoist the car.

2. A hoisting apparatus comprising-a car to be hoisted, an electricmotor for hoisting it, a bin from which material to be hoisted is supplied to the car, said bin having a bin gate for controlling the supply of material to the car, means for causing the closing of the bingate when the material in the car reaches a predetermined weight, means for controlling the closing of the gate independent of the weight of the material in the car,

. and means operated by the closing of the bin gate for causing the motor to be connected to hoist the car, p

3. A hoisting apparatus comprising a car,

.a power operated device for raising and lowering said car, a bin from which material is supplied to the car when at the bottom of its travel, said bin having a gate which is automatically opened when thecarreaches the bottom of its travel, means for causing the closing of said gate when the weight of thematerial supplied to said car has reached a predetermined value, means for'controlling the closing of said gate independentof the weight of material supplied to said car, and

means operated bythe closing of the bin power operated device to raise the car. I g

4. A hoisting apparatus comprising'a car, a power operated device, for raising and lowering said'car, a bin from which material is supplied to the car when at the bottom of its travel,-said' bin having. a gate which is automatically opened when the car reaches the 'bottom of its travel, means for causing the closing of'said gate when the weight of the material supplied to said car has reached a predetermined value, means for controlling the closing of said gate independent of the weight of the material su plied to said ear, means operated by the, closing of the bin gate tocause the power operated device to raise the car, and means for causing the power operated device tojstop raising the car when the latter reaches the top of its travel.

5. In a hoisting apparatus comprising a car, an electr c motor for ralsmg and lowering said car, a bin from which material is supplied to the car vwhen at its lower limit of movement, said bin having a gate which is for controlling the closing of said bin gate 1 independent of the weight of the material in the car, and means operated by the closing of the bin gate for causing the completion of the motor circuit in the proper direction to cause it to raise the car.

a 6. A hoisting apparatus comprising a car, an electric motor for raising and lowering said car, a bin from which material is sup plied to the car when at its lower limit of movement, said bin having a gate which is automatically opened by the car as the latter approaches its lower limit of movement, means for causing the closing of said bin gate when the weight of the material in the car reaches a predetermined value, means for controlling the closing of said bin gate independent of the weight of the material in the car, means operated by the closing of the bin gate for causing the completion of the motor circuit in the proper direction to cause it to raise the car, and means for stopping said electric motor when the car reaches its upper limit of movement.

7. In combination, a car which is movable between two limits of movement, a power opera-ted device for moving the car between said limits of movement, a bin from which material is supplied to the car when the latter is at one limit of its movement, said bin having a gate which is opened by the car as the car reaches its limit of movement, means for causing the closing of the bin gate when the weight of the material supplied to the car has reached a predetermined value, separate means for controlling the closing of the bin gate, and means controlled by the closing of said bin-gate to move said car toward the other limit of its movement.

8. Incombination, a car which is movable between two limits of movement, a power operated device for moving the car between said limits of'movement, a bin from which material is supplied to the car when the latter is at one limit of its movement, said bin having a gate which is opened by the car as the latter reaches its limit of movement,

means for causing the closing of the bin gate when the weight of the material supplied to said car has reached a predetermined value, separate means for controlling the closing of the bin gate, means controlled by the closing of said bin gate for causing the I said power operated device to move said car toward the other limit of its movement, and means for stopping said car when it reaches said other limit of its movement.

between two limits of movement, an electric motor for moving said car between said hm- .--its of movement, a'bin from which material is supplied to said car when it is'at one limit of its movement, said bin having a gate which is opened by the car as it approaches its limit of movement, means for causing the closing of said bin gate when the weight bf the material supplied to the said car able between two limits of movement, an

electric motor for moving said oar between said limits of movement, a bin from whlch material is supplied to said car when it is.

at onelimit of its movement, said bin having a gate which is opened by the car as it approaches its limit of movement, means for causing the closing of said bin gate when the weight of the material supplied to said car from said bin has reached a predetermined value, other means for controlling the closing of said bin gate, means operated by the closing of the bin gate for causing current to be supplied to said motor to cause it to move the car toward the other limit of movement, and means for stopping said mo tor when said car has reached said other limit of its movement.

11. In a skip hoist, the combination of two skips, a poweroperated device for moving said skips oppositely between upper and lower limits of movement, a bin from which material is supplied to the skip at the lower limit of its movement, said bin having a gate which controls the supply of said material to said skip and is opened automatically when a skip approaches the lower limit of travel, means causing the closing of said gate whenthe weight of the material the skip at the bottomand lower the skip at the top.

12. In a skip hoist, the combination of two skips, a power operated device for moving said skips oppositely between upper and of said bin gate when the weight of material supplied to the skip at the bottom has reached a predetermined value, means for controlling the closing of said-bin gate in- I dependent of the weight of the material supwhen a skip approaches the lower limit of travel, means for causing the closing of said bin gate when the weight of the material supplied to the skip at the bottom has reached a predetermined value, means for controlling the closing of said bin gate independent of the weight of the material supplied to the skip, means operated by the closing of the bin gate for causing said power operated device to raise the skip at the bottom and lower the skip at the top, and means for stopping the movement of said skips by said power operated device when the position of the skips with relation to their llmits of movement has been reversed.

14. In a skip hoist, the combination of two skips, a power operated device'for moving said'skips oppositely between upper and lower limits of movement, a bin from which material is suppliedto the skip at the lower limit of its movement, said bin having a gate which controls the supply of material to said skip, means for causing the closing of said bin gate when the weight of thematerial supplied to the skip at the bottom has reached a predetermined value, manually operated means for controlling the closing of said bin gate, means operated by the closing of the bin gate for causing 'sald poweroperated device to raise the skip at the bottom and lower the skip at the top, and means for stopping the movement of said skip by said power operated device when the osition of the skips with relation to their llmits of movement has been reversed.

15. In a ski hoist,'the combination of two skips, an e ectric motor for raising and lowering said skips, the simultaneous movement of the two skips being in opposite directibns, a' bin from which material to be hoisted is supplied to the skip at the bottom, said bin having a gate WlllCh controls the supply of material to the skip at the bottom and is automatically opened as either skip approaches the bottom, means for causing the closing of the bin gate when the load in the skip at the bottom reaches a predetermined value, means for controlling the closing of the bin gate independent of the. load 1n the sklp, and a switch operated by the closing of the bin gate'for controlling the operation of said electric motor.

16. In a skip hoist, the combination of two skips, an electric motor for raising and lowering said skips, the simultaneous movement of the 'two skipsbeing in opposite directions, a bin from which material to be hoisted is supplied to the skip at the bottom, said bin having a gate which controls the supply of material to the skip at the bottom, means for causing the closing of the bin gate when the load in the skip at the bottom reaches a predetermined value, means for controlling the closing of the bin gate independent of the load in the skip, and a switch operated by the closing of the bin gate and controlling the operation of said electric motor.

17. In a skip hoist, the combination of two skips, an electric motor for raising and lowering said skips, the simultaneous movement of the two skips being in opposite directions, a bin from which material to be hoisted is supplied to the skip at the bottom, said bin having a gate which controls the supply of material to the skip at the bottom and is automatically opened as either skip approaches the bottom, means for causingthe closing of the bin gate when the the closingof the bin gate independent of load in the skip at the bottom reaches a Y predetermined value, means for controlling the load in the skip at the bottom, a switch operated by the closing of thebin gate and controlling the operation of said electric motor, and means for stopping the operation of the skips by. the motor when the skips reach their limits of movement,

18. In combination,-a movable car, a bin means operated by the car for opening thev bin, means controlled by the weight of material supplied to the car for closing the bin, means for controlling the closing of the said bin independent of the weight of the material supplied to the car, means controlled by the closing of the bin for starting the car,

and means controlled by the movement of the car for stopping the car.

20. In-comb1nation, a movable car, a bin from which-material is' supplied to the car,

means operated by the car for opening the.

bin, manually controlled means for controlling the closing of said bin, and means operated by the closing of the bin for control ling the car. I

21. In combination, a movable car, an electric motor for operating it, a gate through which material is supplied to said car, man ually operated means for controlling the closing of said gate, and means controlled by said gate for controlling said motor.

22. The combination of a skip, a bin from which material is supplied to the skip, said bin having a gate, manually controlled means for controlling the closing of said bin gate, and means controlled by the closing of the bin gate'for controlling the operation of the skip.

23. The combination of a pair of skips movable between two limits of movement, a bin from which material is supplied to a skip when it is at one limit of its movement, said bin having a gate for controlling the supply of material to a skip, manually operated means for controlling the closing of said bin gate, and means controlled by alternate closings of the gate for producing opposite operations of the skips.

24;. The combination of a pair of skips movable between two limits of travel, an electric motor for operating said skips, a bin from which material is supplied to a skip when it is at one limit of its travel, said bin having a gate which controls the supply of material to a skin. means controlled by'the weight of material supplied from the bin to a skip for causing the closing of the gate when such weight has reached a predetermined value, means for controlling the closing of said gate independent of the weight of material supplied from the bin, and means controlled by alternate closings of said gate for causing opposite operations of said motor.

25. The combination of a pair of skips movable between two limits of travel, an electric motor for operating said skips, a bin from which material is supplied to a skip when it is at one limit of its travel, said bin having a gate which controls the supply of material to a skip, manually controlled means for causing the closing of said bin gate, and means controlled by alternate closings of said gate for causing the opposite operations of said motor.

26. The combination of a pair of skips, an electric motor for operating said skips,

' a reversing switch for said motor, a gate controlling the supply of material to said skips, manually controlled means for causing the closing of said gate, and means controlled by alternate closings of said gate for causing opposite closings of said reversing switch.

27. In combination, a pair of skips, an

electric motor for-oppositely reciprocating them between two limits of movement, a re- .versing switch for the motor, a gate through which material is supplied to each of the skips when it is at one limit of its movement, means independent of the skips for said reversing switch oppositely upon alternate closings-of said gate.

29. In combination, a pair of skips, an electric motor for oppositely reciprocating them between two limits of movement, a reversing switch for the motor, a gate through which material is supplied to each of said skips when it is at one limit of its movement, means independent of said skips for controlling the closing of said gate, means controlled by said gate for elosing'the reversing switch oppositely upon alternate closings of said gate, and means for causing the opening of said reversing switch when the skips reach their. limits of movement.

30. In combination, a skip, an electric motor for reciprocating said skip between two limits of movement, a reversing switch for the motor, a gate through which material is supplied to said skip when it is at one limit of its movement, means independent of the skips for controlling the closing of said gate, means controlled by the closing of the gate for causing the closing of said reversing switch, means for automatically accelerating said skip upon the closing of said reversing switch, and means for first automatically decelerating the skip and then causing the opening of the reversing switch as the skip approaches a limit of its movement.

e 31. In combination, a skip, an electric motor for reciprocating said skip between two limits of movement, a reversing switch for the motor, a gate through which material is supplied to said skip when it is at one limit of its movement, means independent of the skips for controlling the closing of said gate, means controlled by the closing of the gate for causing the closing of said reversing switch, means forautomatically accelcrating said skip upon the closing of said reversing switch, and means for causing the opening of the reversing sw1tch as the slap approaches a limit of its movement.

32. In combination, a car movable between two limits of movement, an electric motor for operating said car, means for automatically controlling said motor to cause it to reciprocate said car between said limits of :i go

movement, automatically operated means for controlling said motor to produce an operation of said car between the same limits of movement, and means for reversing the action of said controlling means.

33. In combination, a car movable between two limits of'movement, a motor therefor, a gate controlling a supply of material to said car when at one limit of its movement, means independent of said car for causing the closing of said gate, means operated by the closing of said gate for causing the motor to reverse the car to move toward the opposite limit of its movement, means controlled by the movement of the motor for stopping the car when it reaches the opposite limit of its movement, and means for reversing the effect of said reversing means.

34. In combination, a car movable between predetermined limits of movement, a gate through which material is so plied to the car when at one of its limits 0 movement, a motor for operating said car, a reversing switch for the motor, means independent of the car for causing the closing of said gate, means operated by the'c'losing of said gate for causing the closing of said reversing switch in the proper direction to move the car toward the other limit of movement, and means controlled by the movement of the car for stopping such movement when such other limit of movement is reached.

35. In combination, a skip, means for actuating said skip, a bin from which material is supplied to said skip, means operated by the car controlling the bin, means 0 erated by the closing of the bin for controlling the car, and means associated with said last mentioned means for reversing the eflect thereof.

36. In combination, a skip operating between limits, means for'normally reversing the skip when it hasreached one of its limits, and means for reversing at will the efi'ect of said last mentioned means.

37. In combination, a skip operating be tween limits, a direction switch automatically operated when the skip it at one limit, and manually operated means for reversing the effect of said direction switch.

38. In combination, a skip operatingbetween limits, 3. direction switch automatically operated when the skip is at one limit, manually operated means for reversing the effect of said direction switch, and means for stopping and starting said skip irrespective of its position.

39. In combination, a skip operating between limits, adirection switch adapted to be operated when the skip is at one limit, manually controlled means for controlling the operation of said direction switch, and manually operated means for reversing the effect of said direction switch.

40. In combination, a ski tween limits, a direction switch adapted to be operated when the skip is at one limit, manually controlled means for controlling the operation of said direction switch, manually controlled means for reversing the effect of said direction switch, and means for stopping and starting said skip irrespective of its position.

41. In combination, a movable car, a gate through which material is supplied to said car, a direction switch operated automatically by the operation of said gate, manually controlled means for causing a movement of said gate to operate said direction switch, and manually controlled means for reversing the efi'ect of said direction switch, all of said'manually controlled means being located at a single control point.

42. In combination, a skip, a motor for controlling the operation of said skip, a gate for controlling the discharge of material to operating besaid skip, control means for said motor for eiiecting the operation thereof in either direction, an operative connection between said gate and said control means, said'gate being operative for motor control purposes in response to the weight of material in said skip, and auxiliary means operable at the will of an operator for causing 'such operation of said gate as is efiective to'control the operation of said motor.

Milwaukee, Wis, April 30, 1912.

In testimony whereof I aflix my signature, in the presence of twowitnesses.

RAY C. NEWI-IOUSE: