US2310314A - Kerf-cutting mining machine - Google Patents

Description

F eb. 9, 1943.

T. E. PRAY KEMP-CUTTING MINING MACHINE Filed July 12 1941 6 Sheets-S het 1 Feb. 9, 1943., I T. E. PRAY 2,310,314

- KER'F-CUTTING MINING'MACHINE Filed July 12,1941 6 Sheets-Sheet 3 ,Feb. 9, 1943. T. E. PRAY KERF-CUTTING MIN ING MACHINE Filed July- 12', 1941 6 Sheets-Sheet 4 mm m 5 Q, w I. A u w m a T. a w q m WTMMMMWMW 9 5 J Z 5 4 v i Feb. 9, 1943 PRAY 21,310,314

KERF-CUTTING MINING MACHINE I Filed July 12/1941 6 Sheets-Sheet 5 30 F .13

Mme

I I WE Br" ATTOIENEY Feb. 9, 1943; T. E. PRAY 2,310,314

KERF-CUTTING MINiNG MACHINE Filed July 12, 1941 6 Sheets-Sheet 6 uwzm-rola T/wmas Pray ATTOB NE Patented Feb. 9, 1943 REEF-CUTTING MINING MACHINE Thomas E. Pray,

man Manufacturing Company,

corporation of Illinois Application July 12, 1941, Serial No. 402,052

16 Claims.

This invention relates to improvements in kerf-cutting mining machines, and more particularly to track mounted machines having a plurality of superimposed cutter bars adapted to cut relatively thick bands of coal or dirt from coal seams, and load the material as cutting proceeds.

The principal object of my invention is to provide a machine of the character described, having means for adjusting the cutting height of the cutter bar at varying levels ranging from the mine floor to the roof of the mine.

A machine of the present invention employs many of the features of machines disclosed in my prior Patent No. 2,082,199, issued June 1, 1937, and prior application Serial No. 362,743, filed Oct. 25, 1940, but includes an improved form of cutter head having three cutter bars, together with a novel means for supporting the cutter head for vertical adjustment well in advance of the truck, and with means for conveying the cuttings rearwardly to the truck for final discharge rearwardly of the latter, in all positions of adjustment of said cutter head.

The invention may best be understood by reference to the accompanying drawing, in which Figure 1 is a plan view of a machine constructed in accordance with my invention;

Figure 2 is a side view of the machine shown in Figure 1;

Figure 3 is an enlarged longitudinal section of the cutter head;

Figure 4 is an enlarged longitudinal section of the rear end of the cutter head including its driving connection and a portion of the cuttings conveyer;

Figure 5 is a detail plan view of the cutter head drawn to a slightly smaller scale than Figures 3 and with a part of the side frame shown in section and with a part of the frame broken away at the front thereof;

Figure 6 is a horizontal section taken on line 56 of Figure 3;

Figures 7, 8 and 9 are transverse sections of the cutter bars, taken on lines 'l'l, 8-3 and 9--$, respectively, of Figure 5;

Figure 19 is an enlarged fragmentary detail section taken on a longitudinal vertical plane, showing the cutter head supporting members in elevated position;

Figure 11 is a fragmentary detail plan view :51" wing the central and rear part of the machn' with certain parts shown in section;

figure 12 is a detail side view of the rear end of the machine, with certain parts shown in section;

Chicago, 131., assignor to Good- Chicago, Ill, :1.

Figure 13 is a detail section taken on line l3!3 of Figure 11;

Figure 14 is a detail section taken generally on line M-I4 of Figure 11; and

Figure 15 is a detail section of a sliding sheave forming part of the turntable rotating mechanism.

Referring now to details of the embodiment of my invention illustrated in the drawings, the machine generally comprises a wheeled truck Ii), herein adapted to travel along mine tracks II and having a base frame l2 with a turntable I3 at the front end to which a cutter head I4 is connected by a forwardly extending, vertically swinging, supporting structure, indicated generally at l5. The wheeled truck 10 and its base frame [2 includes a generally flat deck [2a, and depending front whee1 supports [6, It with track wheels H, il thereon, and similar rear wheel supports [8, it? with track wheels [9, l9 thereon. The wheel supports on opposite sides of the frame are separated so as to leave a central space for a conveyer 22 extending longitudinally of the base l2 beneath the deck [20. for carrying away the cuttings discharged thereon from the cutting mechanisin, as will presently appear.

The turntable 13 comprises an annular base plate 22 having a depending hub portion 23 rotatably mounted in a bearing member on the deck 62a. (see Figures 10 and 14). A circular hopper-like opening 25 is formed through the hub 23 communicating with the cuttings conveyer 28 below the deck.

Extending rearwardly from the turntable base plate 22 are two laterally spaced bearing brackets 21 to which are pivotally connected an upright control frame 28 which is arcuate in horizontal section, and has each of its opposite side walls bifurcated at 29, 29. A pair of upper and lower supporting arms 30, 3B and 3|, 3| are pivoted on pins 32 and 33 respectively between the biftucated side wall portions 29, 29, at opposite sides of the control frame 28. The two pairs of supporting arms and 31 extend forwardly in parallel relation to each other along the turntable and thence downwardly at similar angles, where they are pivotally connected to lugs 34, 3e and 35, 35, respectively, at opposite sides of the cutter head It, adjacent the forward end thereof. Said cutter head has a pair of upright projecting ribs 36, 35 formed adjacent its rear end, having bearing engagement between the inner faces of arms 30 and 3| and assisting in maintaining the respective parts in longitudinal alignment with each other. The supporting arms 39 and Si thus provide a parallel link motion in which the cutter head I4 can be moved vertically into varying parallel cutting planes, perpendicular to the control frame 28.

The rear ends of the supporting arms 39 and 3| are guided between a pair of laterally spaced upright guide frames indicated generally at 37, 3'! mounted on the front of the turntable I3, and projecting forwardly thereof. Said guide frames each comprise a base member 38, two uprights 39 and 49, and a horizontal brace 9|, connecting the upper ends of said uprights 39 and 49.

At the front end of each of the guide frames 37 is a depending bifurcated bracket 43, offset inwardly of the adjacent supporting arms 39 and 3|. Hydraulic elevating cylinders 44, 49 have their lower ends pivotally mounted between the arms of said brackets. Each of said cylinders has a piston 45- therein, and a piston rod 96 extending from its upper end, and pivotally connected to a bracket 41 on the inner side of the adjacent upper supporting arm 39, as shown in Figures I and I3. The hydraulic cylinders 94 serve to raise and lower the cutter head I9 relative to the turntable I3, and maintain said cutter head in any desired cutting plane.

The cutter head I4 includes a housing 59 having side walls 5! and a bottom 52, which has an elongated centrally disposed upright pedestal 53 adjacent its forward end, to which the rear ends of cutter bars 54, 55 and 56 are connected, as by bolts 5! and. 58. The housing 59 also has a second centrally disposed upright pedestal 59 adjacent its rear end, which provides a suitable bearing support for a cutter chain sprocket shaft 69 at the rear of the frame. An intermediate bearing support SI for a second sprocket shaft 62 is mounted on horizontal webs 95, 65a and 66, 66a between the upper ends of the pedestals 53 and 59. As will presently be described in detail, the rear sprocket shaft 59 has chain sprockets 63 and 64 for the cutter chains of the two lower cutter bars 55 and 59, while the inter- V mediate sprocket shaft 62 has a sprocket 62a for the cutter chain of upper cutter bar 59.

As'shown herein, the two lower cutter bars,

with their cutter chains, extend to the rear end of the housing 59, but the upper cutter bar with its cutter chain extends only part way to the rear of'said housing, terminating at a semi-circular upright wall 61 (see Figure 3).

A circular gear casing 69 having a removable cover plate I9, is formed concentric with the V rear sprocket shaft 69, for enclosing bevel gears II and 12 which drive said rear sprocket shaft, as will presently appear. The arrangement is such that the side walls EI and bottom 52 of the housing 59 form in effect channels extending longitudinally along opposite sides of the three cutter bars, and below the gear casing 69. The rear ends of said channels terminate at a cuttings discharge opening (4 at the rear end of the housing 59.

The cutter head also includes means for collecting the cuttings brought back from the kerf by the cutter chains, so that the cuttings will be carried rearwardly along the channel at the advancing side of the cutter bars and through the discharge opening 14 where they will be deposited on a conveyer 75, as will presently be described in detail. The cuttings collecting means shown herein is somewhat similar to that'disclosed in a co-pending application Serial No. 362,743, filed by me on Oct. 25, 1940, and consists of an extension chute I5 telescopically mounted in one of the channels beneath and to one side of the low er cutter bar 56 and arranged to be extended forwardly into endwise engagement with the mine Wall beneath the kerf, to catch the cuttings as they are brought rearwardly by the cutter chains. As herein shown, said chute is disposed in the left-hand channel, since the cutter chains are usually driven in a counterclockwise direction. The chute 16 has an extended upright outer wall TI. The front end of the chute is supported by a horizontal plate 78, which extends laterally beneath the cutter bars and is secured by an upright bolt 79 to a roller frame 89 (see Figure 7). Said roller frame is guided for movement along registering slots 8|, 8| formed centrally of the cutter bars, by means of a plurality of vertically disposed rollers 82, 82 and horizontally disposed rollers 83, 83 carried by the roller frame 89.

A horizontally extending shoe 85 is pivotally supported beneath the front end of chute I6 and is arranged to have sliding engagement with the mine wall when the machine is in cutting position.

Means are provided for yieldingly urging the chute in a forward direction and maintaining it in engagement with the mine wall, which comprise a cable 85 connected at one end to an abutment 81 at one side of the chute. (See Figure 5.) Said cable is trained over a sheave 88 near the front of the housing 59 and thence rearwardly where it is connected to an elongated coil spring 89 in a housing 89a mounted along 1 the side of said housing. The spring 89 is normally under tension to maintain the chute in yielding contact with the mine wall at varying degrees of penetration of the cutter bars.

The cutter chains are driven by an electric motor 99, mounted on the turntable I3 and having flexible driving connections with the cutter head so as to permit freedom of vertical adjustment of the latter. In the form shown herein. the motor is pivotally mounted on pins 9|, 9I carried by a pair of pedestals 92, 92 at the rear end of the turntable I3 between the rear ends of the parallel arms 30 and 3| so that the motor is free to be tilted on a transverse axis. The motor casing has a forward extension 93 forming in effect a cross head with upright wings 94, 94, each having an elongated slot 95 therein slidably engaged by a block 96 carried on the inner side of the adjacent upper parallel arm 39 (see Figure 10). With this arrangement, the motor 99 is rocked upwardly and downwardly with the parallel arms 39 and 3| so as to accommodate itself to various positions of vertical adjustment of the cutter head I4.

The extension frame 93 has two centrally aligned bearing supports 91, 98 for a drive shaft 99 connected with said motor. A horizontal shaft I 99 is journaled in the rear end of the gear casing 69 on the cutter head l4, and is flexibly connected to the drive shaft 99 by two universal joints I9I, I92 and a telescopic shaft I03, of the usual construction.

The shaft I99 has a bevel pinion II fixed thereon, meshed with a bevel gear 12 keyed on the upper end of the rear cutter chain sprocket shaft 69 (see Figures 3 and 4). Said sprocket shaft is journaled at its upper end in suitable bearings I99, I96 and extends downwardly through a depending bearing support I98. An elongated sleeve I9! is rotatably mounted on said bearings I96, I96 and has an outer sleeve I99 carried thereon. The two sleeves I01 and I39 are suitably connected to the lower end of the sprocket shaft 69 as by an end plate H0. The cutter chain sprockets 63 and 64 are formed integral with the sleeve I09, for driving the cutter chains 55a and 56a of the two lower cutter bars 55 and 56 respectively.

Between the two sprockets 63 and as is mounted a sprocket I I3 for a drive chain H4, which leads forwardly to a sprocket II5 keyed on the lower end of sprocket shaft 62. As previously described, the shaft 62 has a cutter chain sprocket 62a keyed on its upper end, for driving the cutter chain 54a of the upper cutter bar 54. The cutter chains of the three juxtaposed cutter bars are arranged as usual to cut a kerf substantially thicker than their respective cutter bars, and in the present instance said cutter bars are disposed so closely to each other that their cutter chains collectively present a substantially unitary side cutting edge for cutting a single kerf, which is substantially the full height of the cutter head I4. The upper limit of the cutting plane of the upper cutter chain 540, is substantially above the gear casing 69 with its drive connection. The two lower cutter bars extend all the way to the rear end of the cutter head frame, beneath the gear casing 69, so as to carry the cuttings from all three cutter bars rearwardly and discharge them upon the conveyer I5 at the rear of saidframe.

The auxiliary conveyer I5 consists of a troughlike frame I i I, having an endless conveyer chain II6 with transverse flights to, H311 thereon, arranged to carry the cuttings along a plate H1. The chains are trained over a pair of sprockets H8, H8 on a sprocket shaft H9 at the front end of the conveyer, and suitable idler sprockets (not shown) at the rear end of said conveyer, as usual.

The sprocket shaft I59 also has bearing at opposite ends in brackets I20, I23 depending from the rear end of housing 53, so as to form a pivotal support for the auxiliary conveyer, permitting vertical swinging movement of the latter when the cutter head is in its various adjusted positions relative to the base frame I2. The conveyer is driven by a chain I2I engaging a sprocket IE2 at one end of the sprocket shaft I I9, and a sprocket I23 on a stub shaft I24, driven from the shaft I33 through bevel gears I25 and I25 (see Figures 4 and 5) The conveyer I5 extends rearwardly to span the space between the cutter head and the turntable I3, and the rear end of said conveyer projects over the front edge of said turntable so as to discharge into the hopper 25 in the center of said turntable. A pair of oppositely disposed upright guide blocks I21, I21 are mounted on the front edge of the turntable to maintain the rear end of the conveyer in registering position over the hopper.

The cuttings delivered to the hopper 25 are carried rearwardly of the machine on. the conveyer 23. In the form shown in Figure 2, the rear end of conveyer 20 is inclined upwardly at ZIa and overhangs the rear end of the machine frame for final discharge upon a mine car or the like in the usual manner.

Hydraulic devices are provided for swinging the turntable I3, for raising and lowering the parallel arms 36 and 3 I and for rocking the control frame 28 to tilt the cutter bars into various cutting planes. A hydraulic pump I33 is mounted at the rear end of the main frame I2 and driven by a motor I3I. The turntable swing mechanism includes a pair of hydraulic cylinders I32, I32 pivotally mounted at their forward ends on brackets I33, I33'rat' opposite sides of the deck I2a. Each of said cylinders has a piston I34 with a piston rod I35 connected at its rear end to a sheave I38. Said sheave is mounted in a block I31 which has a flanged base I38 slidably guided along the deck I2a between a pair of guide bars I39, I39 (see Figures 11 and 15). A pair of flexible cables I40, I40 have their free ends connected to a fixed abut- :ment, as for instance to the rear end of their respective cylinders I32. Each of said cables is trained rearwardly about the sheave I38 and thence forwardly about the periphery of the turntable I3. In the form shown herein, the cables I30 at opposite sides of the machine are integral with each other, and are anchored to the turntable at a single point at the front thereof, as by a clamp MI (see Figure 10). By supplying hydraulic pressure to the cylinders I32, I32 in alternate directions under control of valves of the usual construction (not shown), the turntable, together with the cutter head, can be swung laterally in a relatively wide arc of approximately The elevating cylinders 34, in, effecting lifting and lowering of the parallel arms 33, 3| and the cutter head I4, are actuated hydraulically from the pump I33 under control of other valves, not shown.

Similarly, the control frame 28 is rocked hydraulically by a pair of cylinders I42, M2, pivotally mounted at their forward ends to the rear uprights M! of the guide frame 3? and with their piston rods I33, I43 pivotally connected to the outer ends of pivot pins 33, 33 which connect the upper parallel arms 33, 33 to opposite sides of the control frame 38.

The usual power means may also be provided for operating the conveyer 28, and for propelling the machine along the mine track. In the form shown, a motor M5 is mounted on the base ID at the rear of the turntable i3, and has driving connection with the truck wheels and the conveyer 23 respectively, through suitable gear and drive chain mechanisms which need not be described in detail, as they form no part of the present invention.

While I have herein shown and described one form in which my invention may be embodied, it will be understood that the construction thereof and the arrangement of the various parts may be altered without depaiting from the spirit and scope thereof. Furthermore, I do not wish to be construed as limiting my invention to the specific embodiment illustrated, excepting as it may be limited in the appended claims.

I claim as my invention:

1. In a mining machine, a base, a cutter head including a frame having a cuttings discharge passageway extending longitudinally therethrough, a chain-carrying cutter bar mounted on said frame with its cutter chain arranged to carry the cuttings along said passageway, parallel link means for supporting said cutter head in extended relation in advance of said base and for adjusting said head in a plurality of horizontal cutting planes, conveyer means on said base for carrying the cuttings rearwardly therealong, and an intermediate elevating conveyer having its front end rockably connected to Said cutter head independently of said parallel link means for receiving the cuttings from said passageway and conducting't-hem to said first named ccn veyer in all positions of said cutter head.

2. In a mining machine, a wheeled base, a

turntable rotatably mounted on said base and having a centrally disposed cuttings receiving opening therein, a conveyer beneath said turntable communicating with said opening and extending rearwardly along said base, a chain-carrying cutter head disposed in extended relation in advance of said turntable and parallel link means for adjusting said cutter head to cut in a plurality of planes above and below said turntable, said cutter head having cuttings collecting means thereon associated with its cutter chain, and an intermediate elevating conveyer independent of said parallel link means having its front end rockably connected with said cutter head for receiving the cuttings therefrom and conducting them to the cuttings receiving opening in said turntable in the several positions of adjustment of said cutter head relative to said turntable.

3. In a mining machine, a base, a cutting element including a chain-carrying cutter bar and means for supporting said cutting element in advance of said base for vertical adjustment and endwise tilting movement with respect thereto, including an upright control frame mounted on said base for rocking movement on a transverse axis at a point remote from the front end of said base, a pair of parallel links extending forwardly from said control frame and connected to said cutting element, means for rocking said control frame or holding it in fixed relation with respect to said base for tilting said cutting element endwise, and means adjacent the front end of said base for moving said parallel links vertically relative to said base to adjust the cutting plane of said cutting element relative to said base.

4. In a mining machine, a base, a cutting element including a chain-carrying cutter bar and means for supporting said cutting element in advance of said base for vertical adjustment and endwise tilting movement with respect thereto, including an upright control frame mounted on said base for rocking movement on a transverse axis disposed rearwardly of the front end of said base, a pair of parallel links extending forwardly from said control frame and connected to said cutting element adjacent the front end thereof, upright guide means adjacent the rear end of said cutting element having lateral bearing engagement with said parallel links intermediate their ends, means for rocking said control frame or holding it in fixed relation with respect to said base for tilting said cutting element endwise, and

means adjacent the front end of said base for moving said parallel links vertically relative to said base to adjust the cutting plane of said cutting element relative to said base.

5. In a mining machine, a base, a cutting element including a chain-carrying cutter bar, means for supporting said cutting element in advance of said base for vertical adjustment and endwise tilting movement with respect thereto, including an upright control frame mounted on said base for rocking movement on a transverse axis at a point remote from the front end of said base, a pair of parallel links extending forwardly from said control fram and connected to said cutting element, means for rocking said control frame or holding it in fixed relation with respect to said base for tilting said cutting element endwise, upright guide means on said base having lateral bearing engagement with said parallel links intermediate their ends, and means adjacent the front end of said base for moving said parallel links vertically relative to said base to adjust the cutting plane ofsaid cutting element relative to said base.

6. In a mining machine, a base, a cutting element including a chain-carrying cutter bar, means for supporting said cutting element in advance of said base for vertical adjustment in a plurality of parallel cutting planes including two laterally spaced pairs of parallel links extending forward from said base, a motor rockably mounted on said base between said pairs of parallel links independently of the pivotal connections of the latter, means connecting said motor and links for conjoint vertical adjustment, and flexible drive connections between said motor and said cutting element for driving its cutter chain in the various positions of adjustment of said cutting element.

7. In a mining machine, a base, a cutting element including a chain-carrying cutter bar, means for supporting said cutting element; in advance of said base for vertical adjustment in a plurality of parallel cutting planes including a rocking frame on said base, two laterally spaced pairs of parallel links extending forward from said rocking frame, a motor rockably mounted on said base independently of said rocking frame, means connecting said motor and parallel links for conjoint vertical adjustment, and flexible drive connections between said motor and said cutting element for driving its cutter chain in the various positions of adjustment of said cutting element.

8. In a mining machine, a base, a turntable on said base, a cutting element including a chaincarrying cutter bar, means for supporting said cutting element relative to said turntable in advance of said base for vertical adjustment in a plurality of cutting planes above and below said turntable including two laterally spaced pairs of parallel links having their rear ends pivotally connected at the rear end of said turntable on vertically spaced axes, a motor rockably mounted on said turntable between said pairs of parallel links, means connecting said motor and links for conjoint vertical adjustment, and flexible drive connections between said motor and said cutting element for driving its cutter chain in the various positions of adjustment of said cutting element.

9. In a mining machine, a base, a turntable on said base, a cutting element including a chaincarrying cutter bar, means for supporting said cutting element relative to said turntable in advance of said base for vertical adjustment in a plurality of cutting planes above and below said turntable including two laterally spaced pairs of parallel links having their rear ends pivotally connected at the rear end of said turntable on vertically spaced axes, a motor rockably mounted on said turntable between said pairs of parallel links independently of the pivotal connections of the latter, means connecting said motor and links for conjoint vertical adjustment, and flexible drive connections between said motor and said cutting element for driving its cutter chain in the various positions of adjustment of said cutting element.

10. In a mining machine, a base, a turntable rotatably mounted at the front end of said base, having a centrally disposed cuttings-receiving opening therein, a conveyor below and communieating with said opening and extending rearwardly along said base, a cutting element including a chain-carrying cutter bar, and cuttingscollecting means associated with said cutter bar.

an upright anchoring frame on the rear end of said turntable, two laterally spaced pairs of parallel links connecting said anchoring frame with said cutting element to permit vertical adjustment of the latter in a plurality of cutting planes above and below said turntable, and an intermediate oonveyer extending longitudinally between said pairs of parallel links and connecting the cuttings-collecting means on said cutting element with said cuttings-receiving opening in said turntable in all positions of vertical adjustment of said cutting element relative to said turntable.

11. In a mining machine, a cutter head comprising a frame and a plurality of chain-carrying cutter bars mounted thereon in juxtaposed parallel planes, and drive gearing for said cutter chains disposed within the vertical limits of said cutter chains, including a sprocket shaft rotatably mounted adjacent the rear of said frame and having a drive gear thereon, drive connections to said drive gear at the rear of said frame within the vertical boundaries of said cutter chains, a sprocket on said sprocket shaft in horizontal alignment with one of said cutter bars for driving the cutter chain thereof, another of said outter bars being disposed generally in the same horizontal plane as said drive gear, a chain-driving sprocket and sprocket shaft rotatably mounted at the rear of said last-named cutter bar, and chain drive connections between said sprocket shafts independent of the cutter chains driven thereby.

12. In a mining machine and in combination with a base, a cutting element supported for kerf-cutting movements in extended position relative to said base, said cutting element including a frame, a plurality of chain-carrying cutter bars projecting from said frame in juxtaposed parallel planes and with their cutter chains collectively presenting a substantially unitary side cutting edge adapted to cut a single kerf, the vertical boundaries of said frame being included within the vertical boundaries of said side cutting edge, power operating means for said cutter chains supported on said base, and

having drive connections with the rear of said cutting element within the vertical boundaries of said side cutting edge, said last named drive connection including a bevel gear and pinion at the rear end of said frame disposed generally in the plane of one of said cutter bars, a shaft concentric with said bevel gear, having a sprocket for the cutter chain of an adjacent cutter bar and a sprocket shaft for the cutter chain of said first named cutter bar disposed forwardly of said first named sprocket shaft and chain drive connections between said sprocket shafts independent of the cutter chains driven thereby.

13. In a mining machine, and in combination with a base, a cutting element supported for kerfcutting movements in extended position relative to said base, said cutting element including a frame, a plurality of chain-carrying cutter bars projecting from said frame in juxtaposed parallel planes and with their cutter chains collectively presenting a substantially unitary side cutting edge adapted to cut a single kerf, and driving means for said cutter'chains including a shaft adjacent the rear of said frame having a sprocket engaging the chain of one of said cutter bars, a reduction drive gear in horizontal alignment with a second cutter bar, a second sprocket shaft for said second cutter bar rotatably mounted in advance of said first named sprocket shaft, and drive connections between said sprocket shafts including a drive chain extending horizontally between adjacent cutter bars and independent of the cutter chains carried thereby. V

"'14:. In a miningmachine, a cutter head comprising a frame having a cuttings discharge passageway therethrough, a plurality of cutter bars arranged in juxtaposed parallel planes, with their rear ends mounted in said passageway and having cutter chains guided thereon, drive gearing for said cutter chains including a sprocket shaft rotatably mounted adjacent the rear of said passageway and having a drive sprocket thereon for the cutter chain of one of said cutter bars, drive connections to said drive gear within the upper limits of said cutter chains and in horizontal alignment with the uppermost of said cutter bars, a chain driving sprocket and sprocket shaft for the cutter chain of said last named cutter bar, disposed forwardly of said first named drive sprocket, chain drive connections between said sprocket shafts independent of the cutter chains driven thereby, said cutter bars and chains being disposed in said passageway so as to collect the cuttings from all of said cutter chains and discharge them to the rear of said frame beneath the drive connections to the first named sprocket shaft.

15. In a mining machine and in combination with a base, a cutting element supported for kerf-cutting movements in extended position relative to said base, said cutting element including a frame having a cuttings discharge passageway therethrough, a plurality of cutter bars mounted in said passageway in juxtaposed parallel planes and projecting forwardly from said frame, cutter chains mounted on said cutter bars and collectively presenting a substantially unitary side cutting edge adapted to cut a single kerf, the upper boundaries of said frame being included within the upper boundaries of said side cutting edge, power operating means for said cutter chains supported on said base, and having drive connections with the rear of said cutting element within the upper boundaries of said side cutting edge, the last named drive connections including a bevel gear and pinion at the rear end of said frame disposed generally in the plane of the upper one of said cutter bars, a shaft concentric with said bevel gear having a sprocket for the cutter chain of an adjacent lower cutter bar, a sprocket shaft for the cutter chain of said upper cutter bar disposed forwardly of said first named sprocket shaft, chain drive connections between said sprocket shafts independent of the cutter chains driven thereby, and said cutter bars and chains being disposed in said passageway so as to collect the cuttings from all of said cutter chains and discharge them to the rear of said frame beneath said bevel gear.

16. In a mining machine and in combination with a base, a cutting element supported for kerf-cutting movements in extended position relative to said base, said cutting element including a frame having a cuttings discharge passageway therethrough, a plurality of cutter bars mounted in said passageway in juxtaposed parallel planes and projecting forwardly from said frame, cutter chains mounted on said cutter bars and collectively presenting a substantially unitary side cutting edge adapted to cut a single kerf, and driving means for said cutter chains including a shaft adjacent the rear of said frame having a sprocket engaging the chain of a lower cutter bar, a reduction drive gear on said shaft in horizontal alignment with an upper cutter bar, a second sprocket shaft for said upper cutter bar rotatably mounted in advance of said first named sprocket shaft, drive connections between said sprocket shafts including a drive chain extending horizontally between said upper and lower cutter bars and independent of the cutter chains carried thereby, said cutter bars and chains being disposed in said passageway so as to collect the cuttings from both of said cutter chains and discharge them to the rear of said frame by the action of the cutter chain of said lower cutter bar.

THOMAS E. PRAY.

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