US2561657A - Mining machine - Google Patents

Description

F'. L. FULKE MINING MACHINE July 24, 1951 Filed May 12, 1948 @n A +I R o e o o o o o NN ww Patented July 24, 1951 0 UNITED `STATES PATENT OFFICE MINING MACHINE Frank L. `Fulke, Terre Haute, Ind. Applicationltlay l2, 1948, Serial No. 26,622 4 Claims. (Cl. 262-33) This invention relates to a kerf-cutting coal mining machine and more particularly to-the endless cutter chain of such machine and the cutterbar which supports the chain in cutting position. A mining machine cutterbar comprises a flat elongated element which projects from the machine proper. A channel extends along the lateral edges of this element and around the nose thereof for supporting and guiding the endless cutter chain which is driven by the machine.

The mutually contacting surfaces of the cutterbar and the cutter chain are subject to extreme frictional wear. Such wear is the result of almost an entire lack of lubrication and the presence of abrasive particles produced by the cutting operation. In addition, the weight of the chain and its relatively high rate of travelcontributeto the rapid frictional wear of the bearing surfaces. The cutter bits which are secured to the cutter chain usually aremounted in staggered angular relationship transversely of the lateral edges of the cutterbar in order to effect a cut greater in width than the cutterbar. Accordingly, large twisting stresses are imparted to the cutter chainby the action of the cutter bits. These stresses tend to loosen the joints of the chain and also are transmitted to the cutterbar as forces which tend to spread apart the sides of the chain guideway channel. The chain joints are also subject to extreme frictional wear. A spread chain guideway permits Vexcessive deflection of the chain cutter bits transversely of the lateral edges of the cutterbar. Such deflection results in loss of kerf in the cutter chain, that is, the width of the cut made by the chain is narrower than is permissible for effective operation.

The cutter `chain and the cutterbar are mutually interdependent. A worn chain and loose chain joints quickly will spread apart the sides of the cutterbar `chain guideway. Likewise, a worn and` spread cutterbar guideway rapidly will loosen chain joints. Consequently, these elements of a mining machine are renewed frequently when the machine is in use. A cutterbar is almost always overhauled upon the `installation of a new cutter` chain, and sometimes several times during the life of the chain.

Accordingly, it is an objectlof this invention to provide a cutterbar and cutter chain .that coto a minimum.

It is another object of this invention to provide a cutterbar and cutter chain that cooperate ,toJ

more effectively resist and to reduce the chain guideway spreading effect of the forces imparted to the cutterbar by the twisting action `of the cutter chain.

It is still another object of this invention to provide a cutterbar and cutter chain that cooperate to reduce the amount of transverse deflection of the chain cutter bits upon wear of the cutterbar and cutter chain.

It is still another object of this invention to provide a cutterbar and cutter chain that cooperate to reduce the chain joint loosening eifect of thetwisting stresses set up in the cutter chain.

It is still another object of this invention to provide an inexpensive cutterbar of simple construction but of improved strength and durability.

It is a further object of this invention to provide an improved cutter chain that cooperates with the' improved cutterbar to achieve great eiciency and durability of both elements.

Other objects and advantages of the invention will be evident from the following description and accompanying drawings in which:

Figure 1 is a plan view of a cutterbar embodying this invention operatively connected to a mining machine, a portion only of which is shown. Certain parts are broken away to show details more clearly.

Figure 2 is a transverse sectional view through the cutterbar taken on line 2--2 of Figure 1. A cutter chain embodying this invention is shown in assembled working position on one side of the cutterbar.

Figure 3'is a transverse sectional view, corresponding to Figure 2, of a conventional cutterbar and assembled cutter chain.

`Figure 4 is a sectional view through the cutterhead of the cutterbar taken on line 4 4 of Figure 1.

Figure 5 is a plan view of a portion of a cutter chain embodying this invention.

Referring first to Figure 3, a conventional cutterbar comprises a pair of elongated parallel plates I0 and II supported in spaced position by two side bars I2 and I3 to form a box-like structure. The plates are secured to the bars by rivets I4, usually spaced on three inch centers. The opposite longitudinal margins of the plates I0 and Il overhang the outer sides of the bars I2 and I3 to provide longitudinal, channelshaped, cutter chain guideways, generally indicated` at I5. The outer marginal portions of the opposite side walls of the guideways I5 usually are provided with renewable liners or` J wear plates I6, secured thereto by rivets I1. The

Abar which projects from the head section of "a conventional mining machine 2l (such as shown in Figure 1) to support the cutterbar in operative position thereon.

Referring now to Figures l and 2, the improved cutterbar embodying this invention comprises a pair of spaced parallel plates 22 and 23 having a pair of outwardly directed channel members.

24 and 25 welded to the lateral edges thereof, as indicated in the drawings. The outer surfaces or sides of the plates are flush with the sidesl of the This box-like construction' channel members.

provides a conventional central opening;2li,:one,

end of which slideably receives the mining rnachine post 2ll.` Relative separationY betweenthe v mining machine 2| andthe cutterbar, to properly tension a cutting chain, is effected by. means'ofa screw 10. The screw is threaded througha block 1I secured to `one side of the. cutterbar .and vhas its nosebearing against an` arcuate `.surface on the head section ofthe mining machine 2 I.

Eachchannel member 2li,v 25 has a longitudinal chain guideway 21 integ-rallyformedA therein, as best shown in Figure 2. Theoutervmarginal portions of the oppositevside walls ofthe guideways 21vhaverenewable linersor wear plates l28 riveted theretoand spacedfrom thebottorn of therguideways to form side wall grooves29, asinV a conventional cutterbar construction. Centrallyiprojectingfrom the bottom of each guideway 21-is a longitudinal rib or flange 30, -rectangular in transverse section as 'shown in Figure'Z, and preferably formed integrally with the channel members 24, 25 duringtheir fabrication. The purpose offthis rib is described later. This welded cutterbar construction has been found toxbe cheaper` to fabricate than'a conventional riveted cutterbar. The solid channel members 24, 25 may be'formed economically of rolled steel requiringno machining. Furthermore, the operation of 'drilling multiple rivet holes in the platesvand side bars -of a conventional construction for the rivets lIII is dispensed with. Of greater importance',r however, is the fact that this welded structure resists the spreading forces (later described) exertedfagainst the fside walls of the guideways. bythe twisting action of the cutter chain, to a far greater extent thanra riveted structure. Ina rivetedconstruction, thesespreadingforces are resisted only by the rivets I4. Rivets,'because oftheir'very nature, are not hard and tough,.and consequently stretch under the'load'imposed thereonby 'the spreading forces. In contrast, the welded construction contains no soft rivets I4"to yieldunder the load imposed by the spreading forces and the guideways 21may spread only'throughthe bending of a large mass of solid metal. In actual practice, yit has been found that the integral guideways 21 of the improved welded structure resist, without spreading, much greater forces than those necessary to cause rivet failure.

' A cutterhead supporting block 3 I, havinga nose portion provided with a rounded edge 3'2, is positionedin the other or forward end of the central opening 26 with the nose portion projecting therefrom. The block 3| `is' secured to the ybox-like structure of the cutterbar preferably by rivets 33,l althoughV any suitable securing ymeans will fserve thispurpose. A pair of cutterhead plates 34 .and

the nose: portion of the block 3|.

4 35, substantially semi-circular in plan view, as shown in Figure l, are secured to the opposite sides of the projecting nose portion of the block 3l, preferably by rivets 36. The arcuate margins of the plates 34, 35 overhang the rounded edge 32 of the projecting nose portion of the block to form an arcuate cutter chain guideway 31. The arcuate guideway 31 connects the longitudinal guideways 21 extending along the lateral edges of the cutterbartto enable the cutter. chain to travel around the forward end ofthe cutterbar. Projecting from the inner faces of the cutterhead plates 34, 35, which form the side walls of .the arcuate guideway 31, are opposed arcuate ribs oranges 38 that overlie the arcuate edge 32 of These ribs 38 provide a chain guideway back wall against which the'base of the cutter chain bears while travelling through the arcuate guideway 31. Suitable wear plates 39 are replaceably secured to the outer marminal-portionsof the sidewalls of `the guideway 313easrbyrivets'fv4il, and spaced fromfthe-.guideway back walbto-form side wall grooves 4 I. The-novel `cutter chain. which cooperates.- with thegimprovedcutterheadiis best illustrated in Figure 5.i rIhe chain comprises alternate bit links 42 and connecting links 43. The-bit links haversocketed lugs-44 in whichv cutter bits 45 are replaceablyn mounted; as by set screws 4S. 'The bit` links 42 are of thesaddletypezhav-ing lspaced side plates 41 between which the connecting linksy43 arereceived. The ends of the lin-ks are pivotally connected bywhardened journal pinsI`v 48. Lateral guidingI flangesvr 49 project from the side plates-41v ofreachbitlink. adjacent the-inner edge or base therebf'. The inner edge or:base5l' of the connecting `links isfoffset inwardly rof vthe chain from thefb'asere of: the bit'l links. This construction provides, in effect; a,` central longitudinal groove; rectangular in transverse: vsectionf-in they base or inner surfa'cerof the chain. When `the chainxis assembledfwith the'cutterbar, the groove inxthe base of .'the'chain. receives the'` central longitudinal'ribsorflange 3of the: guidewaysxZT while thetflateral guidingianges'49'fon'the chain are received-inthe:guideway side wall grooves- 29"and Thus the 'cutterbarfguideways 2lhave two bearing'fsurfaces 'which'iare effective laterally of the cutterbar, the edgeof the rib 30 and the guideway back'wallfsurfaces52on either side. thereof. The basef5l ofthe-connecting links rides against the ledge of the rib '33,; while the base 5U o f the'bit link side'fplatestrides against the guideway back wallsurfaces 52. These bearing surfaces atfthe bottom 'of the guideways`21 are subject to .intensive friction during operation of the chain and consequently wear away relatively rapidly.' lThe wear is uniform', however, on all thefsurfaces, so thatitherelative distance, laterally ofthe cutterbarfbetween they rib edge bearing surface andthe b'ackw'all bearing surfaces 52, or, to put it another way, the height of the rib 30, remains substantially constant.

Referringrto the" conventional cutterbar and cutterchain construction shown in Figure 3, it will be notedthat there is no intertting guideway rib and chain groove as in the improved construction a'nd that'the base of the bit links and .the connecting links are substantially flush, i. e.

are in a common plane. When the point 53 of the angularly disposed bit 54, mounted in thel bit link 55 ofthe conventional chain, encounters a hard impurity 5 6^, a large force tends to deflect the bit 54in the direction of the arrow 51, thus exertingla; twisting forcerenY the bit link-55. This force is'` transmitted by thebit link 55 to the cutterbar' in` two components, which act substantiallyyoppositely against theside walls of the-guideways .I5. One force component is substantially concentrated near the outer edge of a wear plate. I at the point and direction indicated generally by the arrow 58. The other force componentis concentrated near the inner or bottom edge of the opposite guideway side wall at the point and direction indicated generally by the arrow 59. It will be noted that the bit link force component indicated by the arrow 59 is exerted at an acute angle against the corresponding side wall. This angular application results in a semi-wedging action of the bit link 55 against the side walls of the guideways I5. Therefore, the guideway side wall resistance fto transverse bit deection also is angular. Such impositive resistance does not positively prevent transverse deflection of the bit 54. When the chain and guideway I5 are closely fitting, the angular deflection of the bit 54, upon such an impurity encounter, is relatively small. When the mutual side bearing surfaces of the chain and guideway wear with use, however, the wedge-like action of the bit link 55 is accentuated, thus'permitting the bit 54 to be deflected through relatively large angles. If this angular deection amounts to as much as the chain is said to lose its kerf. The consequent result is that the width of the cut made by the chain does not exceed the width 0f the cutterbar sufficiently to permit the cutterbar to follow the chain into the cut. When this condition arises, the cutterbar must be replaced.

The twisting force ofthe bit link 55 is transmitted not only to the cutterbar, but also through the chain joints to adjacent bit links. The greater the deflection of the bit 54 and its supporting link55 because of side bearing surface wear, the greater the twisting force applied to adjacent linkS. These adjacent bit links, in turn, apply spreading forces to the guideway side walls. Since, the chain twisting forces are transmitted to adjacent links through the chain joints, rapid loosening of the joints thus occurs. Loose joints require chain replacement. Since the joint loosening effect becomes more pronounced upon side bearing surface wear or guideway spreading, itwill be seen that cutterbar and chain wear are interrelated.

Referring now to the improved chain and cutterbar shown in Figure 2, the rib cooperates with the groove in the base of the chain to provide another set of mutual bearing surfaces that serve not only to reduce the spreading forces exerted against the side walls of the guideways 21 by the cutter chain, but also to reduce the twisting forces transmitted to the chain joints. The sides of the rib 30 provide bearing surfaces for the inner sides of the bit link side plates 41. The encounter of the point 60 of the bit 45 with a hard impurity BI imparts a twisting force 62 to the bit link 42 as in a conventional construction. Two component forces again act substantially oppositely against the guideway 21. One of these forces is concentrated near the outer edge of a wear plate 28, as before, as indicated generally by the arrow 63. The other force, however, is concentrated primarily against a side of the rib 30, as indicated generally by the arrow 64, instead of against the other side Wall of the guideway. Hence, the destructive forces tending to spread the side walls of the guideways 21 are reduced. Furthermore, the actual angular deflection of the bit 45 is lessened because the force 64 exerted against the side of the rib 30 is almost normal to the surface thereof instead of being appliedat an angle thereto like the force indicated by` thearrow 59 in Figure3. In otherwords,` a wedging action of the bit links` 42, which `permits greater `bit deflection, is substantially. eliminated. Since the twisting stresses imparted to the. cutter chain are not continuous, but only intermittent, the mutual bearing surfaces between the sides of the rib y3l) and the inner sides of the bit link side plates: 41 do not wear rapidly. Thus, angular bit deflection does not increase proportionately with the wear of the other mutual bearing lsurfaces between the chain and the cutterbar. The reductionof bit deflection by the rib 30 also effects a reduction in the twisting forces applied to the chain joints. Consequently, the improved construction greatly increases chain life.

Since cutting is performed at the end of the cutterbar, i. e. at the cutterhead, only for a short interval while sumping in, it usually is unnecessary to provide a bit deflection resisting rib on the back wall of the arcuate guideway 31 in the cutterhead. Accordingly, the longitudinal ribs 3D are gradually bevelled at the outer ends thereof, as indicated at 65, to merge with the back wall* surfaces of the guideways 21 and 31 in order to provide for smooth and unobstructed passage of the chain into and out of the longitudinal guide- Ways 21. The inner or mining machine ends of the ribs 30 are similarly bevelled, as indicated at 66, for like reasons. The side wall grooves 4I in the cutterhead guideway 31 are wider than the side wall grooves 29 in the longitudinal guideways 21, in order to permit the chain guiding flanges 49 to travel in a curved path through the cutterhead guideway. Hence, the cutterhead ends of the longitudinal wear plates 28 are gradually tapered in width, as indicated at 61, to correspond to the Width of the cutterhead Wear plates` 39 in order to provide for smooth passage of the cutter chain into and out of the cutterhead guideway 31. The inner or mining machine ends of the y wear plates 28 are similarly tapered in width, as

indicated at 68, for like reasons. l

The elimination of rivets for resisting guideway spreading forces overcomes the necessity of taking the improved cutterbar apart and re-riveting conventional plates IU, II (Figure 3) to side bars I2, I3. The hardened steel wear plates 28 receive most of the frictional chain wear on the side Walls of the guideways 21. These plates 28, When worn, are relatively easily replaced. The wearing of other surfaces of the guideways 21, particularly the back wall and the edge of the rib 30, and the wear of the sides of the chain and its bases does not result in rapid deterioration of the efficiency of either the cutter chain or the cutterbar. The side surfaces of the rib 30 do not wear suiciently to prevent adequate cooperation with the chain before the cutterbar is worn out. Hence, both the chain and guideways cooperate to greatly prolong the effective life to both of these elements.

It is realized that various structural changes may be made by one skilled in the art without departing from the principles of the invention. Accordingly, this invention encompasses all embodiments that come Within the spirit and scope of the following claims.

I claim:

1. In a mining machine, the combination of a cutterbar with a cutter chain; said cutterbar having a chain guideway along each of the longtudinaledges'thereof, each said guideway Abeing in thev form of anI outwardly directed channel. having wear plates secured to and projecting from the opposite channel sidewalls adjacent the outer edges thereof. and a central longitudinal ribyprojecting outwardly from the channel back wall; said cutter 'chain having bit links alternating with connecting links, said bit links being adapted to support cutter bits and being provided with spaced parallel side plates having base surfaces adapted to bear against said guideway back wall, the opposed inner surfaces of said side plates being adapted to bear against the opposite sides of said guideway rib; said connecting `links being pivotally connected to said bit links between said` side plates and having base surfaces offset inwardly of said side plate base bearing surfaces and adapted to bear against the outer edge of said rib.

2. In a mining machine, the combination of 'a cutterbar with a cutter chain; said cutterbar having cutter chain guideways along the longitudinal edges thereof, each saidV guideway comprising an outwardly directed channel having spaced parallel side walls to bear against the 2 sides of said chain and a backwall to bear against the base of said chain, said side walls being provided with opposed longitudinal grooves adjacent said back Wall and said backwall being provided with a central outwardly projecting ylongitudinal track of rectangular section, certain links of said chain having their bases adapted to straddlesaid longitudinal track and being provided with lateral guiding anges adapted to project into said grooves and other links of said chain having their bases disposed in a plane outward of the plane of the bases of said certain links whereby the said other'links may ride upon the top of said longitudinal track.

3. In a mining machine, the combination of of cutterbar with a cutter chain; said cutterbar having a chain guideway along each of the longitudinal edges thereof, each said guideway being in the form of an outwardly directedchannel having opposed longitudinal side wall grooves adjacent the backwall of said channel and a central longitudinalbackwall rib; said cutter chain having bit links alternating with connecting links, said bit links being adapted to support cutter bits and being provided with spaced parallel side plates having base surfaces disposed in a plane offsetvfrom the base surfaces of said connecting links and adapted to bear againstY said guideway backwall, the opposed inner surfaces of said side plates being kadapted to bear 'againsttheopposite sides of said central backwall rib and=said"side plateshaving lateral guidingflanges adapted lto project into said side wall grooves to coniine said chain in said guideway; said connecting links being vpivotally connected to said bit links betweensaid side plates and having base `surfaces adapted to bear against the outer edge of said central .backwall rib. f

4. In a mining machine, the combination. of a cutterbar. with a cutter chain; said cutterbar having cutter chain guideways along the longitudinal edges thereof, each guideway comprising an outwardly directed channel having `spaced parallel side walls and having a back wal1;wear plates secured to said side walls and spaced from said back wall forming opposed longitudinal grooves, each of said grooves .being defin'edby anv edge of said wear-plates, a portion of saidxside Wall, and a portion of saidv back wall, said back wall being provided with a central outwardly projecting longitudinal rib having sidewalls parallel to and spaced from said channel side walls,'said cutterchain having. bit links alternating with connecting links, saidfbit links of saidchain having a central longitudinal groove` in thebase thereof adapted to receive said projecting longitudinal rib,the opposite sidewalls of said groove being parallel to andfadapted to bear against the side walls of said longitudinal rib, said bit'links of' saidfchain having laterally projecting guide flanges-adjacent thev base `thereof projecting into said-'opposed longitudinal grooves to retain-said chain in said guideway.

' FRANK L. FULKE.

REFERENCES CITED The following references are Vof recc'rd'in the file of "this patent:

` VUNITED STATES PATENTS Numbl Germany Oct. 13, 1930

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