US1544072A - Mining machine - Google Patents

Description

June 30, 1925.

M. F. HOLMES M l h 1 NC: MACHINE 1921 3 Sheets-Sheet 1 Filed June 13 June 30, 1925. r 1,544,072

M. P. HOLMES MINING MACHINE Filed June 13, 1921 '5 Sheets-Sheet 2 if", Ju or-r851 ame 30, 1925.

M. P. HOLMES MINING MACHINE F ed June '13. 1921 3 Sheets-Sheet 3 Patented June 39, 1925.

UNITED STATES teasers FATENT FFICE.

MORRIS P. HOLMES, OF CLAREMONT, NEW I-IAIvTP$HIRE, AS$IGNOR TO SULLIVAN TIEACIt-IIITEBY COMPANY, A CORPORATION OF MASSACHUSETTS.

MINING LIACHINE.

Application filed .Tune 13, 1921. Serial No. 477,041.

To all whom it may concern:

Befit known that I, Monms P. Hot-Mama citizen of the United States, residing at Claremont, in the county of Sullivan and State'of New Hampshire, have invented cer tain new and useful Improvements in Mining Machines, of which the following is a full,.clear, and exact specification.

My invention relates to mining machines.

It has for its object to provide an in1- proved mining machine. A further object of my invention is to provide improved cut ter chain and feed mechanism and improved controlling means therefor whereby the cutter chain speed may be kept normal in such a manner as to support the load on the feeding mechanism and thereby balance the feed. Further objects of my invention include the provision of an improved take-up mechanism and the provision of improved truck driving mechanism and improved controlling means therefor. These and other objects and advantages of my improved construction will, however, hereinafter more fully appear.

In the accompany drawings I have shown for purposes of illustration one embodiment which my invention may assume in practice.

, In these drawings, a,

Fig. 1 is a side elevation of my improved machine mounted in transport position upon a. truck.

Fig. 2 is a side elevation on the opposite side of the machine when the latter is removed from the truck. V

Fig. 3 is a plan view of the machine, the feeding and controlling mechanism being shown in section.

Fig. 4: is, a detail sectional view on line of Fig. 2.

Fig. 5 is a detail sectional view on line 55 of Fig. 2. v

Fig. 6 is a verticalsectional view on line 6-6 of Figs. 2 and 3 showing the operative connections between the feeding and cutter driving mechanism, a part of the controlling mechanism being shown in elevation.

Fig. 7 is a rear end. view partially broken away showing the take-up mechanism.

Fig. 8 is a sectional view on line 88 of Fig. 6.

9 is a diagrammatic plan view showing the different positions of the machine during the cutting operationsin a room or the like.

In this illustrative embodiment of my invention 1 have shown for purposes of illustration a machine of the general type described and claimed in my co-pending app'licationSer. No. 312,346, filed July 21, 1919, and comprising a mining machine of the room and pillar type including a frame or casing 1 provided with a bottom plate or shoe 2 adapted to support the machine and slid-able upon the mine bottom or a transport truck 3. As shown, this frame is provided with a rigid forwardly projecting cutter bar 4, the latter carrying a cutter chain 5 equipped with the usual cutter bits 6 and rotatable around the bar by means of a cutter chain driving sprocket 7 beneath the rear end of the frame 1 and above the shoe 2. As illustrated the machine frame also carries at its front end asuitable motor, herein a longitudinally disposed horizontal electric motor, having an armature 8 and controlled by any suitable control mechanism 9 including a controller handle located at the rear of the machine. The armature is herein operatively connectable, through variable reaction mechanism of the type described in my above mentioned application, to the cutter chain driving sprocket 7, a feed operating member 10 herein in the form of a chain sprocket, and a truck driving member ll herein also in the form of a sprocket. As shown a flexible feed member, herein for illustrative purposes shown in the form of the feed chain 12, is also operatively connected to the feed operating member and guided by cooperating guiding members herein in the form of idlers 13, H, and on the frame, in such a manner that, when the member 12 is suitably connected, the machine is adapted to be propelled by its own power relative tothe member 12, the mine bottom, or the truck in a well known manner. Also through a chain connection 17 operatively connectable between the member 11 and the fronttruck wheels 18, the

machine is adapted to propel its truck when mounted in transport position thereon.

It will be observed that the motor armature S is provided at its front endwith a bevel pinion 19, herein meshing with a horizontally disposed lower bevel gear 20. This gear, as shown in Fig. 6, is in turn rotatably mounted in suitable bearings 21, herein of the roller type, concentric with the upper end of a vertical stud 22 having a threaded lower end extending through adjustable bearings 23 and supported on the shoe 2.

The upper end of this bevel gear is also fixed, herein by a key 24, to a sleeve 25 coaxially disposed with and rotatable relativeto the stud 22 and having a pinion 26 on a reduced portion of the sleeve. This pinion 26 in turn meshes with a plurality of sllghtly larger pinions 27, herein three, disposed" be observed that the pinion's 27 mesh with an internal gear 33', which" is journaled on the lower end-of the stud 22'and rigidly united, as by screws 34, with the cutterchain driving sprocket 7, likewise journaled on said stud. The gear 33 is herein also provided with a depending portion 35 havlng'a flange 36 at its periphery running close to' the inner edge of a flange 37 formed on the frame 1, the construction being such that thereby the entry of cuttings or the like into the gearing is effectually prevented at the same time that the gear and sprocket are made removable as'a unit from the top of the frame. Here, attention is also directed to the fact that the outer periphery 38 of the gear 33 is adapted to be engaged by con trolling meansherein in the form of a band brake 39, having one end operatively connected to the frame, as at 40, audits other end connected to a threaded controlling member 41, threaded in a nut 42, extending throii'gh a suitable aperture in the side of the frame and fixed, as by a suitable key 43 to a hand wheel 44 on the outside of the frame. As a result of this construction, it will be observed that the brake band must be applied to obtain any feedwhile the cutter chain is remaining idle. It will further be noted that the cutter chain driving sprocket 7 may be rotated or; idle while the motor is running, the cutter chain driving sprocket being adapted to be driven at full speed when the member 29 is held stationary, and to. have its speedvaried as the member 29 is allowed to rotate faster or caused to rotate more slowly.

Cooperating with the cutter cha1n driving. mechamsm 1s nnproved feeding mechanism.

As shown in Fig. 6 the sleeve 30 on the spider 29 carrieson its upper end a small bevel pinion 45 which in turn constantly meshes with a bevel gear 46. This pinion is keyed as at 47 to a transverse horizontal driving shaft 48 (Fig. 3) which is in turn journaled midway betweenits ends in a bearing 49 carried by a support 50 on the frame. As

shown, this shaft 48 is also removable lat sleeve 56 and suitably connected asby a key 57 to a rotatablevsleeve 58 onthe feedioperating member 10 which is herein shownas' removably carried on the left hand end of the shaft 48 and rotatably mounted inroller bearings 59 in a fixed stepped member 60 closing an aperture 61 in. the side 'of'the frame'and fixed to thel'atter'. Herein this member 60 has an annular chamber or cylinder 62 formed therein receiving an annular friction controlling member or piston 63 adapted when fluid is suitably suppliedto it,

as hereinafter described, to compress or re lease the elements of 'the'friction' clutch at will and thereby cause the feed operating member 10 to be rotated with the shaft 48 whenthe frictionis loaded or to enable the shaft to rotate independently of the member 10 when the friction is released.

Cooperating with the variable reaction cutter chain and feed mechanism and operatively connected to the friction 54 is an improved controlling or dragging friction. Constantly meshing with the bevel pinion 46 is a cooperating bevelf pinion 64 freely rotatable on bearing sleeve65 on the front end of a rearwardly located longitudinally This inner member 55 is in turn suitablyrotatably mounted on the shaft 48 as on a removable bearing extending horizontal stud 66' supported at itsfron't end on the memberbO and at its rear end in a stepped member 67 fixed to the frame as by'bolts 68." This bevel pinion 64 is also suitably connected as throughscrews 69 to a rotatable friction casing. 70"

carrying certain of the elements of a frictionclutch 71, theother elements of which are carried by an inner member 72 carried on a sleeve 73 on the shaft and fixed tothe fixed stepped member 67 as by a key 74. As in the case'of the friction'54, it will also be noted that an aiinular'piston member 75 is mox able'in an annular cylinder 76 in the member 67 and that movement ofthe piston 75 in its cylinder wi'lljaccordingly operate to control the pressure'exerted on the clutch members and the retarding effect of the clutch 71 on the shaft 48.

Cooperating. with thefri'ction' mechanism described is an improved take-up and truck driving mechanism. The rotation of the shaft 48 is imparted through a key 77 to a sleeve 7 8 which has a "bearing 7 9 between it and the member 50 and is connected as by screws 80 to the rotatable casing 81 carrying one of the elements of a friction clutch 82, the other element of the clutch being carriedby an inner member 83 which'is in turn keyed as at 84: to a sleeve 85 on a take-up member 86 corresponding to and interchangeable with the member 10 and similarly journaled in bearings 87 in a stepped member 88 fixed to the frame. As shown, the connection of the two clutch elements is also controlled by an annular piston 89 movable in an annular cylinder 90 formed in the member 8% the mechanism corresponding to that heretofore described as controlinr'y the clutches 54: and 71 and being also similarly controlled as hereinafter described. Attention is also directed to the fact that the truck driving member or sprocket 11 is carried on the end ofthe shaft 48 which extends beyond the take-up member 86, the same preferably being connected to the shaft as by a key 91 and a washer 92 held in place by a threaded member 93. As shown, the flange of a removable flanged bearing sleeve 94. for the take-up member also acts as a bearing for the sprocket 11.

Operatively associated with each of the three friction mechanisms described is a. controlling mechanism of the type described in my above mentioned application but moditied in certain respects to give an independent control of each friction. As shown in Fig. each of these mechanisms includes a cylinder 95 operatively connected, by suitable passages 96 in the stepped members and piping 97 where necessary, to the annular cylinders in the stepped members. In each of these cylinders 95 is a piston 98 movable longitudinally thereof to expel a suitable liquid, as for instance oil, from the cylinder 95 when the handle 99 of the piston 98 is moved, suitable means such as a usual taper thread split bushing 100 being provided so that when the handle is turned, the piston will be held in any given position of adjustment. 'Thus, the frictions may be applied with great facil'ity and in any desired sequence.

Operatively associated with the feed operating member and the take-up member 86 is improved means for taking up the slack which the take-up member may at any time cause to be inserted in the flexible member 12. This means herein includes a pair of pivoted slack absorbing members having upstanding longitudinally swinging arms 101 on opposite sides of the frame at points in rear of the members 10 and 86. 'As shown these arms 101 are provided with. arcuate upper ends 102 leading toward the members 10 and 86 and are formed on a hollow cylinder 103 forming a conduit for the flexible feed member 12 and extending transversel adjacent tie rear thereof. As shown the arms 101 are herein normally held in their slack absorbing position by coiled springs 104 connected between the cylinder 103 and the frame.

In my improved construction the flexible feeding member 12, when the same is connected for cutting, as from right to leftshown, extends from the left hand rib, rearward from the lower sprocket 13, (Fig. 3) to the outer sprocket 14 (Fig. 2) up to the feed operating member 10, backward around the arcuate end 102 on the left hand slack absorbing member 101, around that arm and down the latter to the axis of the slack absorbing member, through the hollow cylinder 103, up around and forward from the other arm 101 (Fig. 1 in dotted lines) to the takeup member 86 and from that member downward to the other member 14 on that side of the machine and then rearward to the idler and the right hand rib. In sumping, i. e. during the starting cut, the left hand free end of the flexible feeding member 12 will be as usual connected at the face, as distinguished from the left hand rib, the connections 011 the machine being the same as above described in connection with transverse cutting. When the ma chine is mounted for transport, however, the flexible feed member will be thrown off of the take-up member 86 so that it will occupy the position shown in full lines in Fig. 1.

In the operation of my improved mechanism during sumping, the machine is fed into the coal under the control of the friction 5d, the brake band being applied until the cutters engage the coal and the friction 71 being re leased as the feed picks up its load. Y-Jhen the machine is sumped in under the coal and connected for the transverse cut, it may be straightened in the cut preparatory to its transverse movement by applying the friction 82 to connect the take-up 86 and thereby swing the machine. During the transverse cut, the machine will normally proceed under the control of the friction. 54. If an obstruction is encountered during the transverse cut, however, angling of the bar is readily obtained by applying the take-up friction S2 to swing the machine. During all of these feeding operations it will be noted that the effect obtained may be varied at any time by connecting o-r discon necting thefriction 71 in such a manner as to increase or decrease the drag of that friction, thelatter friction acting to balance the cutter chain speed with the load on the feed friction 5st in such a manner that the same pull is exerted on the feed chain and on the dragging friction for the same load. It will also be noted that as distinguished from any previous case, the provision herein of the friction '71 enables a take-up to be through the frame at a point used, the friction'71 being necessary to control the take-up which is connected by friction 82 These and other uses and advanthe art.

While I haveinthis application specifically described one embodiment whiclrmy invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration-and that the invention maylBBrlliOClll'lQCl andemoodied 1n various other forms w1thout:departing from its spirit or the scope of the appended.

claimsa nism including a takeup and actuating means therefor including frictional controlling means, and acoope 'ating .fL'lCtlOIlfll controllingimeans adjustable at will and loadable.

to retard: frictionally the rotationof one of the elements of said. frictional controlling.

means. a

3. In" a mining machine, feeding mechanism for feeding the same during cutting transverse kerfs in opposite directions across a face including feed/operating and takeup iembers rotatable on transverse axes, and a'continuous flexible feeding member engaging both of the same simultaneously.

4-. In a mining machine, feeding mechanism for feeding the same during cutting transverse kerfs in opposite directions across a face inclndingfrictionally controlled feed operating and takeupmembers rotatable on transverse axes, and a continuous flexible feeding member engaging both of the samesimultaneously.

5. In a mining machine, feeding mechanism including feed operating and takeup members rotatable on coaxial transverse axes at different speeds, and a continuous flenible feeding member engaging both of the same and disposable in opposite direct-ions from opposite ends-of the machine frame during feeding in opposite directions across a face.

(3. In a mining machine, feeding mechanism including flexible "feeding means, a take-up operated thereby, and automatic means for taking up the slack created by said takeaip mechanism between the latter and said feeding mechanism as it is produced.

7. In a mining machine, feeding mechanism including flexible feeding means, takeup mechanism for inserting slack therein,

, V .take-up member engageable therewith and hat I claim as new and desire to secure between said?feedingmechanism and saidi take-up and means for: automatically taking; up the slack inserted in said: flexible means i as it is produced. i

:8. In. a mining machine, feeding mechaev nism including a feed operatingimember a continuous flexible: feeding member, and take-up mecl'ianisnrfor inserting slack therei inbetween; said feed operatingmem-ber and take-up; and means .for automatically talc-- ing up the slack inserted in said feeding member as it is produced.. I

9. In a miningmachine, feedingmechae nism including aflexible feeding member, a

rotatable on a transverse axis to create slack in said.fl exible member, and automatic means, rotatable on a parallel axis fortakingi up the slack created.

10. In a mining machine,feeding mechaw nism including aflexible feeding member,a take-up operative to create slack therein, and automatic means operableinthe same plane as said take-up: member for absorbing the slack created.

11. In 'a mining machine, flexible feeds ing means, feeding mechanism including feed operating and take-up members cooper. ating therewith, and means movingin the plane of each of said lastlmentionedmembers automatically operative to absorb slack in said flexible means.

12. In a mining machine, a continuous flexible feeding member, feeding mechanism including feed operating and take-up W1 members engageable therewith, and means movable in'the plane of' each of said last: mentioned members for automatically ab.- sorbing slack in said flexible member.

13-. In a mining machine, a continuous flexible feeding member, feeding.mechanisnzr including feed operating and take upmembers engageable therewith, and, a resiliently connected means movable in the plane of; each of said last mentioned members for ab sorbing slack in said flexible member.

' 14. In combination, in a room and pillar, mining machine, feeding means including; winding members rotatable thereon on} coaxial transverse axes and each alternatively operative as a feed operating or as a takeup member, and a continuousflexible feeding member engaging. said members at points between its ends- 15. In combination, in a room and pillar mining machine, feeding means including winding members rotatable thereon on coaxial transverse axes and each alternatively operative as a feed operating or as a takeup member, a continuous flexible feeding meme ber engaging said members at points between its ends, and means for varying the length of thevportion thereof betweensaid winding members. a

16. A room and pillar" mining machine 139 having feeding mechanism including feed operating and takeup members each directly drivable by power independently of the other, a continuous flexible feeding member engaging said members, and means for supporting on said machine the portion of said flexible member extending between said members.

17. A room and pillar mining machine having feeding mechanism thereon inc-luding feed operating and take-up members each directly drivable'by power independently of the other, a Continuous flexible feeding member engaging said members, and means for supporting on said machine the portion of said flexible member extending between said members including a feed member guide on said machine.

18. A room and pillar mining machine having feeding mechanism thereon including feed operating and take-up members on opposite sides thereof, a continuous flexible feeding member engaging said members, and means for supporting on said machine the portion of said flexible member extendin'gbetween said members including a transversefeed member passage on said machine.

19. A room and pillar mining machine having feeding mechanism thereon including feed operating and take-up members, a continuous flexible feeding member engaging said members, and means for supporting the portion thereof between said members and on said machine including a passage and guiding means between said passage and said members. V

20. In a mining machine, a frame having an aperture therethrough, feeding mechanism including feed operating and take-up members on said frame, and a flexible feeding member engaging said members and passing through said; aperture.

21. In a mining machine, a frame having an aperture therethrough, feeding mechanism including feed operating and take-up members on said frame, and a flexible feeding member engaging one of said members and passing through said aperture to the other thereof.

.22. In a miningmachine, a frame having an aperture therethrough, feeding mechanism including feed operating and take-up members on sald frame, a flexible feeding member engaging one of said members and passing through said aperture to the other thereof, and means between said aperture and said first mentioned members for absorbing slack in said flexible member.

23. In a mining machine, a frame having an" aperture therethrough, feeding mechanism including feed operating and take-up members on said frame a flexible feeding member engaging one of said members and passing through aid aperture to the other thereof, and resiliently connected means tween said aperture and said first mentioned members for absorbing slack in said flexible member.

24. In a. mining machine, a machine frame,"feeding mechanism thereon includ ing a feed operating member and a take-up member, a continuous flexible feeding member cooperating with each of said members, and means for automatically absorbing slack in said flexible member created by said takeup member.

25. In a mining machine, a machine frame, feeding mechanism thereon including a feed operating member and a take-up member, a continuous flexible feeding member, and means carried on the side of said frame for automatically absorbing slack in said flexible member created by said take-up member.

26. In a mining machine, a machine frame, feeding mechanism thereon including a feed operating member and a take-up member, a continuous flexible feeding member, and means carried on the side of said frame and movable in the plane of said take-up 1nember for automatically absorbing slack in said, flexible member created by said take-up member.

27. In a mining machine, amachine frame, feeding mechanism thereon including a feed operating member and a take-up member, a continuous flexible feeding member, and means carried on the side of said frame and movable in the plane of said feed operating member for automatically absorbing slack in said flexible member created by said take-up member.

28. In a mining machine, feeding mecha nism including a rotating shaft, feed operating and take-up members connectable thereto, and common frictional controlling means loadable to positively retard rotation of eithenof said members.

29. In a mining machine, feeding mechanism including a rotating shaft, a feed operating member, a take-up member, means for operatively connecting said members to said shaft, supplemental means controlling the rotation of either of said members when connected to said shaft, and a truck driving member carried by said shaft. i

30. The combination with a room and pillar mining machine, of flexible feeding means thereon including feed operating and take-up members rotatable on co-axial transverse axes bearing constantly the same relation to said machine frame and located on the opposite sides thereof, a continuous flexible feeding member, and means for operatively connecting the latter to said members to feed said machine laterally in either direction.

31. The combination with a room and pillar mining machine, of flexible feedin means thereon including feed operating and take up members rotatable on coaxial verse axes and located on the opposite sides thereof, a continuous flexible feeding member operatively connected to said members,

and means for actuating saidmembers to ,feed said machine toward either end of said flexible member.

3.2.The combination with a room and pillar mining machine, of feeding mecha nism thereon including feed operating and take-up members rotatable on coaxial transverse axes and located on the opposite sides thereof, a continuous flexible feeding element operatively connected to'botli of said members to feed said machine in either direction during a normal cutting operation, and

means for rotating either member.

The combination with a room and pillar mining machine, of feeding mechaiiism thereon including independently controllable feed operating and take up mem- 'bers rotatable on eo-axial transverse axes and located on the opposite sides thereof, a

continuous flexible feeding element opera-.

' tively connected tofbothjof said members,

and means"for rotating either member at different speeds.

34 The combination with a room and a pillar mining machine, of feeding mechanism thereon including independently controllable feed operating and take-up members rotatable on co-axial transverse axes and located on the opposite sides thereof, a continuous flexible feeding element operatively connected to both of said members, and

means for taneously. V V

35. The combination With a room and pillar mining imachiiie, of feeding mechanism thereon including feed operating and rotating said members simultalie-up members rotatable on co-axial trans verse axes and located on the opposite sides thereof, a continuous-flexible feeding element operatively connected to both of said members to feed said machinein either di- 'rection during a normal cutting operation,

and means for rotating said members simultaneously or either offthe same at Will.

36. In a mining machine, a mach ne frame,

feeding mechanism thereon including frictionally controlled feed operating and takeiip members rotatable ontransv-erse axes and 7 located on the opposite sides'of'said frame, an idler located on a parallel axis adjacent each of said' members, and a single continuous flexible feeding member engaging said members and said idlers.

37. In a mining machine, a machine'frame, feeding mechanism thereon including feed operating and take-up members rotatable ion sides of said frame, ai-continuous flexible transverse axes and located on the opposite 'Qfeeding member engaging both of said members, guiding idlerstherefor located on a parallel ax s'ad aeent each of said members, and cooperating guiding means for directing the op'posite'euds of said flexible member laterally' from opposite ends of said ,Pgame. 38. In a mining machine, a machine 'ran e, feeding mechanism thereon including feed operating and take-up membersrotatableon transverse axes and located on the opposite sides of said frame,"an idler located on. a parallel axis ad acent eacl of said members,

a'flexible feeding member en'gagingsaid members and said idlers,xand a slack a bsorbing member engaging said flexible mem her at a point between said. feed operating and take-up members.

39. In a mining machine, a machine Yframe, feeding'mechanism thereon including feed operating and take-up members rotatable on transverseaxes and located on the opposite sides of said frame, an idler located on a parallel axis adjacent each of said members, a flexible feeding member engaging said members and said jidlers, and

slack absorbing members 'movable 'in the plane of said feed operating and takerup members and located on the opposite sides of the frame and respectively engaging said flexible feeding, member as it passes off of said feed'operating member and as itpasses on to said take-up member.

40. A mining machine. having a frame, feed operating and takeup members thereon, a flexible feeding member associated iiig-from' said members and in opp'ositedirections froinopposite'ends of said frame during cutting across a face and a portion intermediate said members, and means for guiding the last mentioned portion trans versely of said machine aiid'between the ends and the upperandilou er sides ofsaid frame. i

42. A mining HlaCl11l1611'iLVll 1g a frame, a flexible feed member associated therewith and comprising portions extending 111 01)- posite directions from opposite endsofsaid frame during cutting across a face and an intermediate portion, and a recess formed in said frame intermediatethe endsthereof to guide said intermediate portion of the flexible member.

43. A mining machine'having a frame, feed operating andtake up members thereon, a flexible feeding member associated there-With and comprising portions extending from said members and inopposite iiirections from opposite ends of said frame during cutting across a face and a portion intermediate said members, andm'eans for guiding said last mentioned portion longitudinally and transversely of saidmachine frame and supporting it thereon.

In a mining machine, feeding mechanism including a plurality of clutches, and

a supplemental clutch engagable to retard' any of said clutches, said first mentioned clutches comprising driving elements and elements adapted to be connected with said driving elements to be driven thereby and. said last mentioned clutch being engageable to effect retarding of said driving elements Whether or not said other elements are con nected for drivin 45. In a mining machine, feeding mechanism including a feed operating friction clutch and a takeup operating friction clutch, and a supplemental friction clutch loadable to retard either of said clutches.

E6. In a mining machine, cutting mechanism, feeding mechanism mechanically con nected thereto and driven by the reaction thereof and including a plurality of friction clutches, and a supplemental friction clutch controlling either of said clutches.

IT. In a mining machine, feeding mechanism including a plurality of frictional clutches, and a cooperating controlling frictional clutch connectable at Will With one of the elements of either of said clutches.

48. In a mining machine, feeding mechanism including a plurality of frictional clutches, and a cooperating frictional clutch connectable at will to one of the rotating elements of one of said clutches and opera tive to retard the latter.

49. In a mining machine, feeding mechanism including a plurality of frictional clutches, and a cooperating frictional clutch connectable at will to one of the elements of said clutches and operative to retard said element.

In testimony whereof I affix my signature.

MORRIS P. HOLMES.

Images