US1501795A - Underground mining machine - Google Patents

Description

July 15 1924. 1,501,795

A. K. MITCHELL UNDERGROUND MINING MACHINE Filed Oct. 2, 19:22 13 Sheets-Sheet l .S SN w N C P%| rv il mn .Q R Trw n l l L Mi, 1w 2 M 1U. V l u ce N rl m o Q D afi-m .WN WM. c m !,\\\U| e o I\| a 0 o O 0 n i@, a .I o b-No .o e .Q Nh. -I c mmm o uw i1 I MiN/ nw E n f I 1 x M n O 0 Sw im 0%.@ D w Il w@ 41 July 15 1924.

A. K. MITCHELL UNDERGROUND MINING MACHINE Filed Oct. 2, 1932 13 Sheets-Sheet 2 July 15, 1924. 1,501,795

A. K. MHTCHELL UNDERGROUND MINING MACHINE Filed oct. 2, 1922 13 sheets-Sheet 3 C. WW

Mmm/ww Juy 15, 1924. 1.501,795

A. K. MITCHELL UNDERGROUND MINING MACHINE Filed Oct. 2, 1932 13 Sheets-SheeiI 4 GWW July 15 l1924. 1,501,795

A. K. MITCHELL UNDERGROUND MINING MACHINE Filed Oct. 2, 19z2 13 Sheets-Sheet 5 ,4H/w ff. Amm/1 CWM A. K. MITCHELL UNDERGROUND MINING MACHINE July 15, 1924.

vFiled Oct. 2, 1922 13 Sheets-Sheet 6 July 15, 1924. Y

A. K. MITCHELL UNDERGROUND MINING MACHINE Filed Oct. 2, 1922 13 Sheets-Sheet '7 um, m

July 15 ,v 1924. 1,501,795

A. K. MITCHELL UNDERGROUND MINING MACHINE Filed Oct. 2, 1922 13 Sheets-Sheet 5 3;, CWM@ July 15,1924. 1,501,795

A. K. MITCHELL UNDERGROUND MINING MACH-I NE Filed Oct. 2, 1922 13 Sheets-Sheet 10 July 15 .'1924.

A. K. MITCHELL UNDERGROUND MINING-MACHINE Filed Oct. 2, 192:2 13 Sheets-Sheet ll VME ATTORSE Y NHN vom, Nevn Nw E En SQN MSM mow on @n wm. Nhm

July 15 1924. v

- A. K. MITCHELL UNDERGROUND MINING MACHINE 13 Sheets-Sheet l2 Filed Oct. 2

July 15, 1924.

A. K. MITCHELL UNDERGROUND MINING MACHINE Filed Oct. 2, 1922 13 Sheets-Sheet l5 INVENTOR l 6 gg M ATT RNEY Patented July l5, 1924.

UNITED STATES 1,501,795 PATENT OFFICE.

ARTHUR K. MITCHELL, 0F BRONXVILLE, N EW YORK, ASSIGNOR '101 ST. JOSEPH LEAD COMPANY, OFNEW YORK, N. Y.,

A CORPORATION or NEW Yom.

UNDERGROUND MINING MACHINE.

Application led October 2, 1922. Serial No. 591,689.

T o all whom z't may concern.'

Be it known that I, ARTHUR K. MITCHELL, a citizen of the United States, and a resident of Bronxville, county of Westchester and State of New York, have invented certain newand useful Improvements in Underground Mining Machines, of which the following is a specification.

This invention relates to Aan improved underground mining machine and is in part., a'continuation of my prior application for patent tiled July 21st, 1920, Serial No. 397,881.

Generically considered, it is the primary object and purpose-of this invention to provide a machine of the above character which is especially designed for operation in mine corridors of limited height,'and Which will be exceedingly mobile and can be readily operated in a comparatively restricted space, as for instance, between the roof supporting pillars, in the loading of the transporting vehicles with ore.

It is another object of my invention to r provide an improved system of control enabling the operator Without changing his position upon the machine, to properly manipulate the ore collecting dipper or shovel andto position the same above the ore receiving and transporting vehicle, or to effect the bodily movement or travel of the machine.

The present invention also contemplates the provision of an improved mounting for the dipper or shovel carrying boom and means for imparting a longitudinal forward thrust or retracting movementl to the boom so that the shovel or clipper after being filled,lmay swing with the superstructure of the machine between spaced roof supporting pillars in the mine corridor and thus dispose the shovel in a dumping position over the ore receiving vehicle. y

In one practical embodimentof the invention I provide av rotatable superstructure mounted upon atractor'supported frame and a longitudinally traveling shovel-carrying boom carried by the superstructure. Three electric motors of the reversible type are mounted upon the superstructure and each connected in suitable electric circuits, one of said motors operating the tractor actuating mechanism or the boom actuating mechanism, another of said motors actuating the boom hoisting means, while the third motor actuates the superstructure rotating means.- By the manipulation of suitable circuit controlling switch levers, the operator may render one, or simultaneously two or three, of the motors operative to effect the desired operation, each of the motors being preferably equipped with a magnetic brallie so that when its circuit is broken, the operation of the motor is instantly stopped.

It is also one of the detailed objects of the invention to provide ample automatic means for breaking the circuit of the boom operating motor to limit the forward thrusting movement and the retracting movementof the boom, and also to provide automatic circuit-breaking means Ifor the hoist motor to limit the elevated position of the shovel or dipper as well as to stop the hoist motor, when during its lowering motion the shovel or dipper strikes the mine floor or other obstruction.

Another of the detail-objects of the invention is to provide simple and eicient means acting to positively lock ythe tractors against movement to hold the machine as a whole, in a st-ationary position While the boom and shovel are being operated to gather' and load the ore.

In accomplishing the aforementioned objects I have at the same time succeeded in devising a machine primarily designed for underground mining operations which, in view of its manifold capabilities, is of relatively simple construction, light in weight, and wherein the various operating parts are compactly arranged and not liable to get out of order.

With the above and other objects in view, the invention consists in the improved form, construction and relative arrangement of the several elements, as will be hereinafter more fully described,` illustrated in the accompanying dra-Wings and subsequently incorporated in the subjoined claims.

In the drawings wherein I have illustrated one practical embodiment of the invention and in which similar reference characters designate corresponding parts throughout the several views,

Figure 1 is a top plan view of an underground mining machine, constructed m accordance with my present invention;

Figure 2 is a side elevation Aof the machine, the boom and shovel being shown in full lines in its lowered retracted position A frame ;l

and in dash lines in the retracted elevated` tractor supported frame, the superstructure being removed; V

Figure 6 is a transverse section taken on the line 6-6, of Figure 1;

Figure 7 is a front end elevation of the tractor frame, the tractors being shown in section; e

Figure 8 is a top plan view partly in section of the superstructure support-ing Figure 9 is an enlarged plan view with certain parts shown in section to more clearl illustrate the driving connection between tlie motors and the superstructure rotating mechanism and the tractor actuating mechanism;

Figure 10 is a sectional view through one of the motor brakes with parts thereof in elevation, taken on the line 1 0-10 of -Figure l;

Figure 11 is a section taken on the line 11-11 of Figure 10;

Figure 12 is an end elevation of the brake;

Figure 13 is a detailv sectional View through the brake engaging wheel on the shaft of the boom operating motor and illustrating the manually operable clutch connection between said wheel and the boom operating gearing;

Figure 14 is an enlarged detail section showing the universal connection between the boom gudgeons and the carriage blocks mounted for longitudinal movement on the superstructure of the/machine, said section being taken on the line 14-14 of Figure 1;

Figure 15 is a transverse section taken on the line 15-15 of Figure 1, showing the worm gear driving connections between the operating motors and the hoisting drum and boom operating shaftrespectively; Figure 16 is a diagrammatic view showing the Fboom and shovel in full lines in the fully extended lowered position with relation to the machine superstructure and in broken lines in various other positions which the boom and shovelmay assume in the operations of hoisting and dumping the material.; Figure 17 is a diagrammatic View showing a conventional wiring of the electric motor controlling circuits with the operators control levers and the automatic circuit breaking devices;

Figure 18 1s an enlarged detail plan view, partially diagrammatic illustrating the relation of its several control levers with respect to the operators, seat;

lFigure 19 is an enlarged plan view showmaigres ing the actuating means for the forward and rear limit switches of the boom operating motor;

Figure 2() is a detail elevation of the actuating means for the forward limit switch;

Figure 21 is a section taken on the line 21--21 of Figure 19;

Figure 22 is a detail elevation of the lower limit, switch for the hoisting motor;

Figure 23 is a section taken on the line 23--23 of Figure 19;

Figure 24 is a detail elevation of the 0perating means for the rear limit switch of the boom operating motor;

Figure 25 is a longitudinal sect-ion on the centre line of the dipper or shovel, which section intersects the shovel and boom head, to ether with the latch device;

ligure 26 is a side view of the dipper or shovel and a longitudinal section through one ofthe spring bumpers or shock absorbers; and

Figure 27 shows details of theA frame or bracket carrying the collector shoes.

In the embodiment of the invention illustrated in the accompanying drawings as shown by Figs. 2, 3, 4; 5, 6, 7, and 8, the supporting frame 5 for the tractor of the machine is of general rectangular form in plan and includes a centrally elevated body portion 6 at each end of which and at the opposite sides of the frame, the longitudinally extending bearing supports 7 and 8, respectively, are formed. The frame extensions 7 receive the bearings 9 for one end of the respective tractor driving shafts 10 which are located at opposite ends of the frame 5. The inner ends of the shafts 10 are journaled in suitable bearings provided in the lower portion of a housing 11, said housings being re-c spectively secured centrally to each end of the body 6 of the frame.

Upon the frame extensions 8 longitudinally adjustable bearings 12 are mounted in which shafts 13 are journaled. Any conventional means may be employed for the purpose of adjusting the bearings 12 relative to the frame struct-ure.

At each side of the machine, the endless tractor treads 14 are engaged upon the sprocket wheels 16 and 17 secured respectively upon the outer ends of the shafts 1C and 13 which project from each side of the machine frame. The fiexible tractor'treads between the spaced sprockets are supported and guided by means of a plurality of flanged rollers 18 suitably mounted upon spaced stud shafts fixed in each side of the machine frame. The tractor driving shafts 10 are actuated to propel the endl-ess flexible tractors in either direction by means of mechanism which will be presently described. y

Upon the'body portion 6 of the frame 5 an annular toothed rack 19 is securely fixed in any preferred manner and within thisl ard 23 centrally fixed therein, the lower end of said standard being engaged within an upwardly projecting boss 24 formed upon the frame bodyn. The latform 22 is pro- -vided at its opposite si es with depending longitudinally extending walls 25, said platform being also formed with an annular depending flange 26 surrounding the rack 19, said ange merging into the walls 25 at opposite sides of the superstructure` To the lower edge of the ange 26 a ring or annulus 27 is fixed and projects inwardly beneath the lower edge of the rack 19 and thus prevents an oscillating movement of the rotatable superstructure withl respect to its axis. The means whereby this superstructure, together with the operating mechanism mounted thereon, may be rotated with respet to the tractor supported frame 5, will also be fully disclosed in the subsequent description.

As shown by Figures 6 and 14, to the outer `face of each of the depending walls 25 of the superstructure platform 22, a channel bar 28 is secured by means of the bolts 29, saidbolts passing transversely through guide rails 30 which are secured upon the channel bar flanges in opposed relation to each other. The longitudinally extending ribs 31 of the guide rails 30 are engaged in suitable channels provided in the carriage blocks 32 whereby said blocks may freely tralvel longitudinally between the guide rai s.

chain 33 are pivotally connected, a turn buckle 34 or other suitable slack take-up means being interposed in the length of this chain, as illustrated in Figure 2. The chains 33 engage with the sprockets 36 mounted upon shafts suitably supported on the forward end of the superstructure, said chains being positively driven by the sprockets 37 which,I are xed upon opposite ends of a transverse shaft 38 journaled in suitable bearings on the rear end of the platform 22.

The shovel or dipper carrying boom as herein illustrated, consists of tubular side members 39 whicli'are connected at their forward ends by means of 'ai boom head 40; Figures 1, 2, 3. The members 39 at their rear ends are supported from the carriage blocks 32 inthe manner clearly `shown in To opposite sides of each carriage -block 32 the ends of a link type sprocket Figure 14 of the drawings, wherein it will be noted that a gudgeon 41 extends transversely through eac-h boom member and projects from one side thereof, said gudgeon being suitably fixed to the boom member as by means of the pin 42. The projecting end portion of the gudgeon 41 is reduced in diameter and tapered as at 43, said tapered end of the gudgeon being tightly dra-wn into the bore of a universally movable socket member 44 shaped as a zone of a sphere, mounted in the carriage block 32 by means of the nut 45 which is engaged upon the reduced threaded projection 46 of the tapered end 43 of the gudgeon. There are thus provided substantial connections between the boom members and the traveling carriage blocks which allow a ,free vertical pivoting or rocking movement of said boom members relative to the carriage blocks when the boom, together with the shovel or dipper carried thereby, is `hoisted or lowered with respect to the superstructure of the machine. Since these connections arel of the ball and socket type, the carriage blocks 32 cannot be subjected to any eccentric or torsional stresses due to any side thrust on boom or dipper.

From the above it will be'seen thatthe means for projecting and retracting the boom consists of the sprocket chains 33 driven by thesprockets 37 and the carriage blocks 32 upon which the side arms or members 39 of the boom are mounted at their rear ends. This boom operating means is actuated by a reversible motor to be hereinafter referred to, andin certainv of the subjoined claims .I have included this motor or primary power source as an element sep arate Ifrom the boom operating means as above defined.

The dipper, bucket, shovel or skip, as it is variously termed, may be of any suitable or preferred construction, in so far as the essential features of the present invention is concerned and it may be mounted upon the boom head in various ways. However, for purposes of illustration I have herein shown the. shovel 47 as an open top scoop, Figures l, 2, 16, 25', and 26, pivotally `mounted for a tilting movement upon the trunnions 0r pins 48 fixed in the downwardly and forwardly projecting arms 49 of the boom head 40. Figure 25 is a central longitudinal section through shovel 47 and boom head 40. Thel shovel 'is so constructed and counterbalanced that when loaded with ore or other f when empty l'ies behind the pins 48; there-` fore, when free to tilt the empty shovel will return by gravity to its normal or digging position. Shovel 47 is held in this latter position by latch 401 which engages the upper end of lug 402. Latch 401 is held against rear end of shovel 47 by compression of spiral spring 403 which is mounted on rod 404 in an annular recess'in boom head 40. To empty the loaded and elevated shovel, the operator presses down aipedal located conveniently near h'is feet, which motion overhauls a spring-actuated retrieving drum upon which cable `405 is wrapped, causing cable 405 to pull lever 406 thus disengaging latch 401, to which lever 406 is attached, from upper end of lug 402, thereby permitting shovel 47 to tilt forwardly and discharge its load. TWhen the forward tilting movement is arrested, as hereafter described, latch 410 engages the lower end of lug 402, thus holding shovel 47 in position of maximum inclination so that its load of Ore may be. completely discharged. Latch 410 is held against rear end of shovel 47 by pres` sure of spring 403 through rod 404. An other pull on cable 405 causes lever 406, through its connections with' latch 401 and rod 404 to disengage latch 410 from lower end of lug 402, thus permitting the empty shovel to tilt backwardly to its normal or digging position, such backward tilting being limited by the striking of buffers 411, of which there is one on each side of the shovel, against arms 40.

Figure 26 is a side view of shovel 47 in its tilted position, showing also a section through one of the two spring bumpers or shock absorbers 407, but omitting details of the latch mechanism. The positions of spring bumpers 407 are also shown by Figures 1, 2 and 3. When shovel 47 is allowed to tilt forward to dump its load, its movement is arrested by the engagement with lugs 409, of which there is one on each side of the rear end of shovel 47, of hooked ends of plungers 408, said plungers acting under the impact to compress springs 412, thus absorbing the shock. Springs 412 are mounted within cylindrical members 407 which are attached to boom head. 40.

A shea-ve block 50 is suitably connected centrally to the boom head 40 and around the sheave therein the cable 51 is engaged; Figures 1, 2 and 3. This cable is trained over and supported by the spaced pulleys or sheaves 52 which are rotatably mounted upon a common axis 53 extending between the upper ends of the standards 54,- said standards at their lower ends being pivotally mounted as at 55 upon the superstructure platform 22. The forward ends of longitudinally extensible rods 56 are also loosely en gaged upon the pulley axis 53 at the outer side of each pulley 52` said rods div/erging with respect to each other in a rearward d 1- rection and being pivotally mounted at their rear ends as at 57. 'These rods 56 may each be of the conventional sectional telescopic construction, suitable means, of course, being provided to securely hold the rod sections in ixed relation to each other. rl`hus, when itis necessary to propel the machine through a connecting passageway or corridor .of very limited height, the standards 54 may be readily swung forwardly and downwardly to a lowered position as indicated by broken lines in Figure 2 of the drawings.

Une strand of the cable 51 extends rearwardly and downwardly from one of the pulleys 52, and is suitably connected to the hoisting drum 58 which is fixed upon. or integrally formed with a sleeve 59 loosely mounted upon the shaft 38 for independent rotation; Figures 9 and 15. The other strand of the cable 5.1 extends over a pulley or sheave l60 mounted in the upwardly eX- tending arm of a bracket 61 which is provided for pivotal or rocking motion upon ,a shaft 62 for a purpose which will be hereinafter explained. From this .sheave 60 the cable strand extends rearwardly and is suitably attached at its end to the larger end of a fusee drum 63 which is keyed or otherwise rigidly iixed upon the shaft 38. The fuses drum 63 is so designed that the cable 51 will be unreeled from it at a variable rate such that when the dipper is being crowded out by the operation of motor 69 as hereinafter described, starting with the dipper lip on the plane of the tractor bottom, the path described by the dipper will be horizontal. By reference to Figures 2 and 16 it will be understood that the boom is projected, or crowded out an equal distance for cach degree of revolution of shaft 38. As the boom and sheave 50 move out, if the lip of the flipper is to travel a horizontal path on the plane of the tractor bottom, cable 51 must be unreeled at a progressively increasing rate, which rate, since the cable is a two part one, must equal at any point twice the corresponding increment in the distance between the points of Contact of the cable with sheaves 52 and sheave 51. A plain cylindrical drum, keyed to shaft 387 would unreel an equal length of cable for each degree of revolu tion of shaft 38 causing an outward and upward path of the dipper; therefore, a-

fusee drum designed as explained, is pro` vided. i

The sleeve 59' of the hoisting drum 58 has a worm gear 64 fixedv thereon with the up per side of which a worm 65 on the shaft 67 of the hoisting motor 66 is engaged; Figures 1, 9 and 15.- This worm and worm gear are enclosed Vwithin a suitable housing 68 mounted on the platform 22. It will thus be apparent that by the operation of the motor 66, the hoisting mechanism can be actuated to lift the boom and hoist the loaded shovel carried thereby/.to the desiredl height, while the'shovel is in its forwardly projected position, in its retracted position, or n any intermediate position.

There is also mounted upon the superstructure platform 22, a second electric motor 69 which operates the boom thrusting and retracting mechanism and also the tractor propelling mechanism of the machine; Figures 1, 2, 4, 7 and 9. A third electric motor 70 mounted on the platform 22 act'nates suitable gearing .cooperating with the fixed rack 19 to rotate the superstructure upon the main frame 5. Each of these motors is of the reversible type and is equipped with a conventional form of magnetic brake. These brakes I have indicated in the accompanying drawings by the numerals 71, 72 and 73 respectively. I have also illustrated one of the magnetic brakes in detail in Figures 10, 11 and 12 of the drawings. It will suflice for the purpose of the present explanation to state that each brake includes opposed magnetically controlled brake shoes 74 which are adapted for friction-a1 braking engagement upon opposite sides of a wheel 75 fixed in any suitable manner upon the motor shaft. The brake shoes 74 normally en age wheel 75 under the spring action, w ien, however, the magnet or solenoid coil is energized, the shoes are magnetically pulled away from the wheel, against said spring action, thus releasing the brake for free operation of the motor.

Upon the end of the shaft of the motor 69 a clutch element 76 is loosely engaged, Figure 13, said element being fixed within one end of a sleeve 77 which extends over one end of the hub portion 78 of the wheel 75. A friction band is carried by the block 79 fixed to the wheel hub and is interposed between the hub wall and the wall of the sleeve 77. .A spring pressed wedge member 80 extends between spaced ends of the friction band and acts to hold the same in tight frictional enuagement with the wall of the sleeve 7 7. ft will thus be apparent that there is obtained in this manner a slip friction connection. between the clutch element 76 and the wheel 75 which is fixed on the motor shaft. This device is desi ned to slip in the event of severe overloa s or sudden impacts, such as would be caused .during forward crowding by the shovel striking an immovable obstruction. Motor 66, which operates the hoisting drum 58 is provided with 4a similar device, as is motor 70, which operates the swinging mechanism, hereinafter described.

A manually shiftable complementary clutch element 81 is keyed upon the shaft 82 which is journaled in the upper part of a housing 83'enclosing the worm gear 84 fixed on the shaft 38 and the worm 85 on said shaft 82 which is engaged with the worm gear 84; Figures 1, 2, 9 and 13. It will thus be apparent that when the clutch element 81 is engaged with the complementary clutch element 76, rotation is transmitted from -the motor through shaft 82 and worm gearing 84 and 85 to the shaft 38 which drives the boom carrying chains 33 to move the boom in the desired direction and either thrust the shovel '47 forwardly to gather the ore therein or to retract the shovel, from which position it may be subsequently hoisted and disposed over the receiving and transporting vehicle. The other end of the sha ft of the motor 69 is also provided with a clutch member 86 with which a complementary clutch member 87 keyed upon the shaft 88 is adapted to co-act; Figures 1, 2 and 9. Between motor. 69 and said clutch elements there is also provided a slip friction device, similar to that previously described but not shown by the drawings. Shaft 88 is journaled in the upper end of a housing 89 and is provided with a worm 90 which is engaged with the worm gear 91 on a transversely positioned shaft 92 mounted in the housing walls,l Figure 6. Upon the inner end of this shaft a beveled gear 93 is fixed and meshes with a similar gear 94 keyed upon a tubular shaft l95 mounted in the hollow standard 23 fixed in the superstructure platform 22. The inner end of shaft 92 is also journaled in one side of this standard. The lower end of the shaft 95 extends below standard 23 and has a beveled gear 96 fixed thereon which is in mesh at diametrically opposite points with the gears 97 and 98, respectively, Figure 4. The gear 97,is keyed or otherwise fixed upon the end of a rearwardly extending shaft 99. The end of this shaft is suitably coupled at the rear side of the frame body 6 to a shaft 100 j ournaled in the upper side of the housing 11 in which the inner end of the rear tractor operating shaft 10 is mounted. 100 is provided with a worm 101 meshing with theworm gear 102 on the shaft 10.

The other gear 98 is loosely mounted-upon a forwardly extending shaft 103 which, at the front side of the frame body 6, is suitably coupled to a shaft 104 journaled in the upper side of the housing 11 supporting the other tractor operating shaft 10. This shaft 104 is likewise provided with a worm 105 meshing with the worm gear 106 on said tractor operating shaft.

The shafts 99 and 103 are supported in suitable bearings adjacent to the gears 97 and 98 respectively, which are mounted in webs or hangers 107 dependin from the frame body 6. A spider 108 1s arranged within the lower end of the boss 24 on the frame bodyV 6 and the upper ends of the arms of a yoke 109 are pivotally mounted in this spider, Fifrures 4 and 6. lThe yoke arms are providedwith rollers 110 engaged The shaft in opposite sides of a peripheral groove formed in a double acting clutch collar 111, said collar having clutch teeth on each of its side faces to engage with similar clutch teeth on the gears 97 and 98 respectively, and being mounted for longitudinal sliding but not for rotation upon end of shaft 103.. A bar 112 is swiveled at its ends in the lower ends ofthe arms of the yoke 109 and to Jthis bar oppositely projecting aXially movable rods 113, are suitably connected, saidrods sliding through suitable bearing guides 114: in the hanger webs 107. Each of said rods 113 at its other end is connected to a slide block 115 supported by the roller 116 mounted in a bracket plate 117 suitably fixed to the frame 5. Abell crank lever 118 is also fulcrumed in each of thcbracket plates 117, one arm of the lever projecting upwardly and being operatively connected with a sliding locking clutch member 119 keyed upon the shaft 99 or 103. These locking clutches are adapted to normally engage with a fixed part 120 surrounding the shaft and depending from the fra-me body 6 whereby said shafts 99 and 103 are locked against rotation. The. bell crank levers are urged to this normal position by means of coil springs 121 engaging the other or horizontal arms of said levers and interposed between said arms and the fixed parts 120, said springs also acting to yieldingly hold rollers 122 carried by the lever arms in the recesses or seats 123 provided in the upper surfaces of the slide blocks 115. I

Within the tubular shaft 95 a rod or shaft 124 is loosely mounted and is provided at its upper end with a hand wheel 125 whereby said rod may be conveniently rotated, Figure 6. The lower end of this rod carries a pin or stud 126 eccentrically offset from the axis of the rod and engaged in a slot 128 provided in a connecting bridge 127 between the arms ofthe yoke 109. It will thus be apparent that when this rod 124 is rotated,-

the pin 126 coacting with the walls of the slot 128 acts to shift the yoke 1.09 in one direction or the other, and thereby engage the clutch collar 111 with the gear 97 or the gear 98, as the case maybe, and to also simultaneously shift the rods 113 so as to actuate the bell crank levers 118 and thereby y release the locking clutches 119 from engagement with the parts 120. VVhenthe collar 111 is shifted to the left from the position seen in Figure 6, it will be obvious that the shaft 103 is connected through the medium of said collar and the gear 97 to the shaft 99 so that both shafts will rotate as a unit. Thus both of the flexible tractor treads will be driven in the same direction for a straight line movement of the machine. When the collar 111 is shifted in the opposite direction and engaged with the gear 98, said gear is locked tolthe shaft 103 so that rotation will be imparted to this shaft from the gear 96 in a direction oppositeto the direction of rotation of the other shaft 99. The tractor treads will thereby be moved in relatively opposite directions so that the machine can be turned or manuvred in a comparatively. restricted space. 4

The clutches 81 and 87 are manually actuated to operatively connect the motor 69 to the 'boom operating gearing or to the tractor operating gearing as the case may be, through the medium cfa lever 224 which is pivotally mounted upon one side of the gear housing 89, 'Figure 9. This lever is provided with an upper arm 225 connected by the rod 226 to a swinging yoke 227 in which the shiftable clutch member 87 is carried. The lever 224 is also provided with a second arm 228 connected by the link 22,9 to one end of a lever 230 which is fulcrumed intermediate of its ends uponvthe superstructure platform 22, the other end of said lever being connected by a rod 231 to the lower part of yoke 232, (Figure 2) which is so fulcrumed on platform 22 that its lower part engages the shiftable clutch element 81. As seen in. Figure 9, when the lever ismoved in one direction toward the center line of the machine, the clutch element 81 is thrown out to disconnect the motor from the gearing operating the boom while the other clutch element 87 is thrown into engagement with the clutch 86 to connect said motor to the gearing operating the tractors. Upon shifting this lever away from the center line of the machine, such condition is reversed and the motor is connected in driving relation with the boom operating gearing and disconnected from the tractor operating gearing.

The superstructure platform with the motors and mechanisms mounted thereon is rotated with relation to the' supporting frame 5, as indicated by the broken line shown in Figure 1, by means of the gearing illustrated in Figures 4 and 9 of the drawings, from reference to which it will be noted that the shaft extension 134 from the motor 70 is provided with a worm 135 meshing with the worm gear 136 on the upper end of a perpendicular shaft 137 mounted in suitable bearings on the platform 22. A pinion 138 is fixed to the lower end of this shaft and meshes with the gear 139 on the upper end of a second perpendicular shaft 140. The lower end of this shaft 140 is in turn provided with a pinion 141 which directly engages with the teeth of the fixed annular rack 19 secured upon the frame. body 6. The upper face of this rack is obliquely inclined as at 142 and upon the same suitably spaced frustro-conical rollers 1-'13 mounted in the platform 22 are engaged,

whereby the superstructure and the parts carried thereby will be adequately supported.

Each of the three collector rings 20 is connected with one phase of the three phase alternating current circuit to which, by means of an insulated three-wire cable, the tractor or truck, is wired. Each of these rings is normally engaged by a collector shoe 144 (a, Y), or c; Figures 17 and 27. The three collector shoes are mounted on a single libre, board 503, the spindles 512 of the shoes sliding loosely through holes in board 503, and shoes 144 are pressed downwards by springs 502 through which pass spindles 512. Each collector shoe 144 is kept in alignment with its collector ring 20 b v a toggle connection with libre board 503. Fibre board 503 is rigidly mounted upon three bolts 508 which pass upwardly with a sliding fit through holes in bracket 501 to a rigid connection with plate 511, bracket 501 being bolted over a suitably located aperture in platform 22. Plate 511, bolts 508, libre board 503 and collector shoes 144 a., Z), and c, are normally held down in position in which rings 20 are engaged by shoes 144 by latch 504 which is pivoted to bracket 501 by pin 509, a notch in latch 504 being pressed against the edge of a hole in plate 511 by leaf spring 505. Latch 504 is connected by rod 160 with lever 152 which is conveniently located near the left hand of the operator, being pivotally connected at 510 with platform`22. If the operator desires to disengage shoes 144 from rings 20, he presses the upwardly projecting forward end of lever, 152 to his left, thus disengaging latch 504 from plate 511, permitting plate 507, bolts 508, fibre board 503, and shoes 144 to rise under the action of spring 506, until shoes 144 are-lifted clear of rings 20 and all current is thereby cut off from the circuits on platform 22. To re-engage shoes 144 with rings 20, the operator presses downward on guard 507 attached to plate 511, until notch in latch 504 snaps over edge of plate 511.

In Figure 17 I have diagramatically represented the various motors, brakes, switches, circuit breakers, cont-actors, and controllers, together with the circuits connecting them. There are three three-phase alternating current squirrel cage reversible motors, of a type, having high resistance, high starting torque and low starting current. Each motor has two primary circuits, one for each directionof each motor, and each of these circuits may be completed by means of double pole magnet switches or contactors which are closed when their magnets are. energized by the manual closing of pilot or secondary circuits at the two master controllers, the central elements, or

levers, of which are indicated at 151 and 153.

If the operator desires to cause the boom and dipper to crowd out, he pushes lever 151 against Contact A, Figures 17 and 13. The following secondary circuit is thus completedz-from collector shoe 144", through points 301, 302, 303, and 304to safety fuse 305, to closure between central lever '151 of master controller and contact A, tio limit switch 157 here assumed closed), through magnet coil 147c to point 306, through contacts of circuit breakers 307 and 308 to point 309, through point 310 to collector shoe 144. Since vmagnet coil 147C is energized by this secondary circuit, the main contacts 147 and 147 b are closed, thus completing the main circuit of motor 69 to canse forward mot-ion of boom and dipper. This main circuit is through solenoid coil of-circuit breaker 308 to point 319, through closure of contacts 147b to point 320, through points 321 and 310 to collector shoe 144C. Regardless of any switch positions, terminal 322 of motor 69 is always connected through points 323 and 301 with collector shoe 144". A circuit is simultaneously closed from point 317 to terminal 324 of b rake 72 of motor 69, from terminal 325 through point 326 to point 323, said points 317 an 323 being on'main circuit of motor G9 previously outlined. Also, when magnet coil 14,7c is energized, auxiliary contacts 147d are closed, thus completing the following secondary circuit: from collector shoe 144b through points 301, 302, 303 to 304, u

through closure of auxiliary' contacts 147d through point 327 to point 328, through magnet coil 154, through points 329, 330 and 311 to collector shoe 1441. Since magnet coil 154c is energized, the main contacts 154a and 154b are closed, thus completing the Jfollowing circuit: from collector shoe 144b throu h points 301 and 302 to point 330, throug closure of contacts 154b to terminal 332 of brake 73 of motor 70,from terminal 333 through closure of contacts 154a to point 331, through point 311 to collector shoe 1449-. From the above it is apparent that` the manual closure of lever 151 and contact A causes crowd motor 69 to operate in such a direction as to cause an outward motion of boom and dipper, and simultaneously energizes and therefore releases magnet brake 72 of motor 69, thus permitting motor 69 to function, as well as also releasing magnet brake 73 of swing motor 7 0, thus permitting platform 22 to rotate slightly and relieve structural stresses should the bucket receive a glancing thrust during

Images