US2926896A - Drive means for continuous mining machine - Google Patents

Description

March 1, 1960 c. B. KREKELER 2,926,896

DRIVE MEANS `FOR CONTINUOUS MINING MACHINE Filed Dec. 50, 1958 BYMvM,

ATTORNE YS.

`points or ends of the bits tent Office 2,926,896 Patented Mar. 1 196@ zpzasss DRIVE MEANS FOR `CNTIIJUOUS MINING MACHINE Claude B. Krckeler, Monfort Heihts, Ohio, assignor to The Cincinnati Mine Machinery Co., Cincinnati,` Ghia, a corporation of Ohio Application December 3i), 1958, Serial No. 783,957 8 Claims. (Cl. 262-29) This invention relates to mine machinery and more particularly to a continuous mining machine for use in cutting into veins of coal or the like.

In continuous mining machines provision is made for supporting and feeding a plurality of clo'sed chains formed of pivoted-together blocks which mount and support bit holders and cutter bits in such a way that the cutting enter into cutting relation with the mineral vein.

to pass around sets of sprockets secured to a pair of shafts, one of the shafts being journaled at the extreme forward end of the machine so that the cutter bits make cutting contact with the mineral vein as they pass around the sprockets on the forward shaft, the upper flights of the chains moving'rearwardly where they pass around the second shaft which is arranged to be driven from any suitable source of power, such as a prime mover connected to the shaft through gearreduction means. With this arrangement, the upper llights of the cutter chains also serve as a moving conveyor effective to move the coal or other mineral matterfrom the cutting area so that it may be collected for removal from the mine, as by means of belt conveyors, coal cars and the like.

The instant invention is directed specifically tov improvements in the manner in which the sprockets are mounted to the forward shaft about which the cutter chains move as `they cut into the mineral vein. Heretofore these forward shafts have been formed by taking a single piece of :rod stock and milling away its outermost ends to provide 'a Vcentral section having a first diameter and outermost our end sections having a second and reduced diameter. In a conventional construction the central` portion of the shaft is arranged to mount three u sprockets in spaced apart relation, the sprockets being splinedV to the shaft, with an additional sprocket splined to the reduced section at each end of the shaft. In addition, pineapples or rotary cutters are tted over the ends of the end sections of the shaft and splined thereto. The shaft is journaled in suitable bearings mounted on the machine frame, the bearings being so arranged that the shoulders between the center section of the shaft and the reduced `end sections will abut against the bearing members `to prevent axial displacementof the shaft.

With the arrangement just described, considerable difficulty h asrbeen experienced Vin accurately aligning the splines in the center section of the shaft with those in Vthe `reduced end sections. That is, by reason of the change in diameter between the central and end sections,

Y itis extremely dicult to set the cutting tool to produce precise longitudinal alignment betveen the splined portions of the three sections. Since, in the conventional assembly, all of the front sprockets are driven in unison from the rear shaft, even the slightest misalignment of any one of the front shaft splines produces an unequal load on the cutter chains. This unequal load not only adversely affects the smooth operation of the cutter but subjects the front shaft to excessive wear and Vinternal The `cutter chains are arranged twisting movement resulting in either distortion or breakage of the shaft as well as mutilation of the splines.

it is a principal object of the instant invention to overcome the difficulties just noted by providing a construction wherein accurate alignment between the splines on the center and outer parts of the shaft is not required, the two outside sprockets, i.e. the sprockets mounted on the end sections of the shaft, being designed to float on the shaft, thereby reducing the load on the outside chains.

A further object of the invention is the provision of a shaft and sprocket arrangement of the character noted `wherein the front shaft is adapted to be driven solely by the intermediate sprockets, i.e. the sprockets secured to the center section of the shaft, and wherein the outside sprockets mounted on the reduced ends of the shaft are rotatably Vreceived on splined inserts which permit the outside sprockets `to seek their own alignment relative to the shaft and the intermediate sprockets. As before the pineapples onthe ends of the shaft are splined directly to the reduced end portions thereof, and hence will be driven by the shaft as it is rotated by means of the intermediate chains and sprockets.

Still a further object of the invention is the provision sprockets in place of the double tooth sprockets heretofore employed in devices of comparable size, the single tooth sprockets serving to permit better tracking of the cutter chains and reducing the tendency of the chains to twist. Preferably, five tooth sprockets will be ernployed in replacement of the four double tooth sprockets heretofore used. This change has been found to reduce joint wear, thereby increasing the life of the joints. At the same time, a fewer number of double bit blocks are required and yet the total number of bits is the same as with the longer pitched'chains.

The foregoing objects of the invention together with others which will appearhereinafter or which will be apparent to the skilled worker in the art upon reading the specification, I accomplish by that construction and arrangement of parts of which l' shall now describe an exemplary embodiment. Y

Reference is now made to the accompanying drawings wherein:

Figure l is a plan View with parts broken away of the cutting end of a continuous mining machine. f

Figure 2 is a vertical sectional View taken along the line 2`-2 of Figure l with the parts at one .side of the machine shown in explodedrelation.

Figure 3 is an elevational view of a sprocket mounting shaft formed in accordance with the invention Y Figure 4 is a schematic View intended to illustrate the mode of operation of the cutting device.

For a general understanding of the invention, reference is first made to Figure 4`of the drawings wherein the front or leading shaft is indicated by the reference numeral i, the shaft having an enlarged center section 2 and reduced end sections 3. it` will be understood that the terms enlarged and reduced are terms of convenience and have been chosen to denote a .center section having a larger diameter than the end sections.

ln the embodiment illustrated a series of three inter mediate sprockets 4 are splined to the enlarged center section ofthe shaft and outermost sprockets 5 are adapted to be journaled on the end sections 3. While in the drav ings (Figure 4), the sprockets E. are showndetached from the shaft 1, this is simply to illustrate that the sprockets 5 are driven independently of the shaft even though they areiournaled on it. The rotary cutters or pineapples 6 are, however, splined to the end sectiousof the shaft and are rotated thereby.

The cutter chain assemblies 7 which pass around the sprockets 4 also pass around coacting sprockets 3 assess@ mounted on splined shaft 9 adapted to be driven through gear box 1f) from any suitable prime mover (not shown). Outermost sprockets 11 are also splined to the rear shaft 10 and connected by cutter chain assemblies 12 to the sprockets 5. It will be understood that all of the sprockets on rear shaft 9 will be driven in unison by the rear shaft. However, as previously indicated, by reason of the varia- Vtion in diameter between the center and end sections of the forward shaft-which is necessary to provide shoulders to prevent axial displacement of the forward shaftprecise alignment between the splines in the center and end sections of the forward shaft cannot be readily obtained, and any misalignmeut of the splines results in misalignment of the sprockets 4 and 5 relative to each other and unequal loading between the intermediate cutter chain assemblies 7 and the outermost cutter chain assemblies 12.

As best seen in Figures l and 2, each of the cutter chain assemblies comprises a plurality `of double cheek chain elements 13 having mounting blocks 14 in which one or more cutter bits 15 are secured. The double cheek elements 13 are connected together by means of intermediate single cheek elements 16, the elements being pivoted together by suitable piutles 17, as will be readily understood, thereby forming an endless cutter chain. While in the embodiment illustrated each of the cutter bit mounting blocks mounts a pair of cutter bits extending in opposite directions, it will be understood that the arrangement may be varied with the bits in staggered relation. For example, single cutter bits may be mounted on given blocks with the bits in either vertical position or inclined to one side or the other. Thus, in a typical chain assembly, adjacent pairs of blocks mounting double cutter bits may be followed consecutively by blocks mounting single bits extending left, right, and left, whereupon, the sequence is repeated.

As also seen in Figures 1 and 2, the front and rear shafts are journaled in suitable bearings, such as the bearings 13 for the shaft 1 and the bearings 19 for shaft 9, the bearings being.V mounted to a machine frame which includes longitudinally extending rib members 20 to which elongated plates 21 are secured, the plates lying between the chain assemblies in the manner illustrated. Side guides or sweeps 22 are preferably mounted on the outermost frame members to channel the material cut from the vein rearwardly of the machine. As will be apparent in Figure 2, the bearings are so arranged that they will abut against the enlarged center section 2 of the shaft, thereby preventing axial displacement of the shaft. While the enlarged center section 2 may be formed as an integral unit, i.e. of a length to mount all of the intermediate sprockets 4, it mayV also be divided into a plurality of spaced apart sections 2a (see Figure 3) with the intermediate portions 23 of the shaft machined to a lesser diameter, as for example the same diameter as the end sections 3. Where this is done, intermediate bearing members 18a (Figure 2) may be provided between the spaced apart enlarged center sections.

The outermost sprockets are fitted on the end portions of the shaft 1 by means of splined inserts 24 which are received on the splined outer ends 3 of the shaft. The center openings or bores 25 of the sprockets 5 are of a size to be fited over the inserts 24, in the manner seen in the left-hand portion of Figure 2. Preferably the titting will be a snug one although it will be such that relative aligning movement may be effected between the insert and the sprocket.

The center bores 26 of the rotary cutters or pineapples 6 are also splined and are fitted directly on the ends of the shaft and secured in place by means of clamping plates 27 and threaded nuts 2S. The pineapples are thus driven directly by the shaft 1 which in turn is driven by the intermediate cutter chains. While some driving force may be transferred to the shaft through the outermost sprockets 5, these sprockets are essentially independent of the shaft insofar as the driving forces are concerned. That is, the outermost sprockets are free to seek their own alignment and, while they will be driven in synchronism with the intermediate sprockets, they are not relied upon to power the shaft but rather to convey the outermost chain assemblies.

It has been found that the arrangement just described has solved a serious production problem in the machining of the sprocket mounting shafts and, at the same time, has increased the life of such shafts by eliminating the torque or twist which resulted from improperly aligned sprockets. The construction also reduces the load on the outermost chains and at the same time increases their wearing ability. It also permits the use of single tooth sprockets which are more desirable in that the cutter chains track better and vibration is reduced.

Having thus described the invention in an exemplary embodiment, what I desire to protect by Letters Patent is set forth in the claims which follow, it being understood that modifications may be made in the invention without departing from the spirit of it.

I claim:

1. In a mining machine wherein a plurality of cutter chains are arranged to engage a plurality of sprockets mounted on a common shaft, and wherein said shaft is adapted to be rotated by said cutter chains, and wherein rotary cutters are adapted to be secured to the ends of said shaft, said shaft having a center section of a first diameter and end sections of a second diameter which is smaller than the said first diameter, splineways in both the center and end sections of said shaft, a plurality of sprockets splined to the center section of said shaft and fixed against rotation relative thereto, a cylindrical member splined to each of Vsaid end sections, and a sprocket mounted on each of said cylindrical members, said last named sprockets having cylindrical bores corresponding to the outer surfaces of said cylindrical members, said last named sprockets being rotatable relative to said members, whereby said last named sprockets are free to iioat on said members and seek their own alignment relative to the sprockets splined to the center section of said shaft.

2. The construction claimed in claim l wherein rotary cutting elements are splined to the outermost end portions of the end section of said shaft.

3. The construction claimed in claim'2 wherein the center section of said shaft is of uniform diameter throughout the length of said section, and wherein the splineways therein extend continuously throughout the length of said center section.

4. The construction claimed in claim 2 wherein the center section of said shaft comprises a plurality of splined segments of equal diameter interconnected by bearing segments of lesser diameter than said splined segments.

5. The construction claimed in claim 4 wherein a sprocket is mounted on each of the splined segments of said center section.

6. In a mining machine wherein a plurality of cutter chains are adapted to be engaged by sprockets mounted on a common shaft, said shaft having a center section of a first diameter and end sections of a second diameter which is smaller than said first diameter, splineways in the center and end sections of said shaft, a plurality of sprockets splined to the center section of said shaft and xed against rotation relative thereto, additional sprockets mounted on the end sections of said shaft, said additional sprockets each having a circular insert the outer surfaces of which are in sliding contact with the bores of said sprockets, the inner surfaces of said inserts being grooved to tit the splineways of said end sections, whereby said additional sprockets may seek their own alignment relative to said first named sprockets, thereby eliminating the necessity for accurate alignment between the splineways on said center section and said end sections.

sections of said shaft, said rotary cutting elements being 1 fhft` 2,705,626 Bau Apr. 5, 1955 2,92ZS,896 5' t 6 7. The construction claimed in claim 6 wherein rotary 8. The construct-ion claimed in claim 7 wherein said cutting elements are splined -to end portions of the end sprockets are al1 of single tooth character. v

adapted to 'be driven by `said shaft upon driving movement References Cited in the me of this Patent of said first named sprockets by the cutter chains attached 5 UNITED STATES PATENTS

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