US2170927A - Mining machine - Google Patents

Description

N. D. LEVIN MINING MACHINE Aug'. 29, 1939.

Original Filed Feb. 14, 1933 [NVENTOR /Y//5 D Lev/n A TT'Y 4 Sheets-Sheet l N. D. LEVIN MINING MACHINE Aug. 29, 1939.

Original Filed Feb. 14, 1933 4 Sheets-Sheet 2 N. D. LEVIN MINING MACHINE Aug. 29, 1939.

Original Filed Feb. 14, 1953 4 Sheets-Sheet 5 ATT'Y Aug. 29, 1939. N. D, LEVIN 2,170,927

MINING MACHINE I OriginalFiled Feb. 14, 1933 4 Sheets-Sheet 4 Ill H //v VEN TOR /Y//s D. Le w}? Patented Aug. 29, 1939 UNITED STATES PATENT OFFICE MINING MACHINE f Ohio.

Application February 14, 1933 SerialNo. 656,697 Renewed November 21, 1938 20 Claims.

My invention relates to mining machines particularly of the type adapted to the mining of coal although it should be understood that it may have a general application.

One of the objects of the present invention is plane of the kerf-cutter or the cutter bar.

Another object of the invention is the provision of improved and efficient apparatus for supporting a cutter bar against strains exerted during the feed of the cutter of the bar.

More particularly it is the object of the present invention to provide for an elongated chain kerfcutter supporting and guiding mechanism which will efficiently resist strains exerted during feeding of the kerf-cutter particularly when fed arcuately.

Other objects of the invention will appear hereinafter. The novel features and combinations are set forth in the appended claims.

In the accompanying drawings Fig. 1 is a plan View of a track mounted mining machine embodying my invention;

' Fig. 2 is an elevational view of the track mounted mining machine shown in Fig. 1;

Fig. 3 is an enlarged sectional elevation of the front portion of the mining machine shown in Fig. 2;

on a line 55 thereof;

Fig. 6 is a diagrammatic plan view showing the relative position of the parts on the turntable shown in Fig. 1;

Fig. 7 is an enlarged sectional elevation on the line l-1 of Fig. 6 looking in the direction of the arrows;

Fig. 8 is a sectional detailed elevation of the clutch for controlling the sprocket connected to the chain driving mechanism and means for adlusting elevations of the kerf-cutter;

Fig. 9 is an enlarged sectional elevation of the connections to the mechanism for swinging the turntable at a feeding speed;

Fig. 10 is an enlarged sectional elevation of the pawl and ratchet mechanism for effecting reversal of the swinging feeding movement of the turntable and kerf-cutting mechanism;

Fig. 11 is an elevational View showing brake mechanism associated with the shaft of the worm which constitutes part of the swinging feeding mechanism for the kerf-cutter;

Fig. 12 is a sectional elevation showing part of the structure illustrated in Fig. 10;

Fig. 13 is a sectional elevation taken on the line l3-l3 of Fig. 10.

Fig. 14 shows a detail of Fig. 3;

Fig. 15 is a side view of means for automatically releasing the clutch shown in Fig. 3; and

Fig. 16 shows an enlarged detail of Fig. 15.

Referring to Figs. 1 and 2 it will be seen that the supporting frame 14 is mounted on Wheels I5, I5 which are adapted to travel on the mine track l6. Mounted on the frame [4 is a supporting ring l'l around which is distributed a series of supporting rollers [8, I8. The ring I! is mounted for adjustment on the three upright standards l9, [9 at the front end of the frame l4 and on the rear central standard I9 at the central portion of the frame M, as shown in Fig. 1. The ring I! may be adjusted in elevation and inclination by means of such structure as that shown in my re-issue Patent No. 17,603, granted February 25, 1930, for an improvement in Mining machines. The adjustments in elevation and inclination may be effected by poweroperated mechanism controlled by clutches individual to each standard as illustrated in my Patent No. 1,353,054, granted September 14, 1920, for an improvement in Mining machines. It should be understood that after the ring I! has been adjusted in elevation and inclination it remains in fixed relation to the supporting frame I4 during the operation of the kerf-cutting mechanism.

Mounted on the ring ll so as to partake of the adjustments thereof in elevation and inclination is a turntable 20. As shown in Fig. 3 a peripheral flange 2| supports the turntable 20 on the rollers I8. By means of an electric motor 22 mounted on the turntable and connected to apparatus as illustrated in my aforesaid patents the turntable 20 may be rotated relatively to the supporting ring I! and about the center thereof.

On the rear portion of the frame M are mounted an additional electric motor 23 and powertransmission mechanism 24 for effecting transportation of the machine along the mine track Hi from place to place in the mine. The powertransmission mechanism 24 is also connected to a cable reel 25 on which is wound a cable 25 extending to the source of power for the two electric motors 22 and 23 which are independently operated and controlled.

Fixed rigidly to the turntable 20 and extending radially therefrom is a supporting arm 21 to which is adjustably connected a depending bracket and guide frame 28. Guided vertically in the depending bracket 28 is a cutter head 29 to which is secured the elongated cutter bar 39 having an endless chain cutter 3| guided around the periphery thereof. A driving sprocket 32 meshes with this chain and is secured to the lower end of an extensible torque shaft 33 to the upper end of which is connected 2. sprocket 34. An endless sprocket chain 35 meshes with the sprocket 34 at the upper end of the torque shaft 33 and also with the sprocket 36 shown at the left hand end of Fig. 3. As shown in Fig. 1 a slotted plate 31 connects the rear end of the bracket 28 with the radial arm 21. By means of bolts 39, 39 extending through the slots in the plate 3'! the bracket 28 may be secured rigidly in adjusted position relative to the arm 21 after the slack in the endless sprocket chain 35 has been adjusted.

As shown in Fig. 3 the armature shaft 49 which projects from the motor 22 in Fig. 1 has secured thereto a bevel pinion 4| which meshes with a horizontal bevel gear 42 secured to the vertical shaft 43. By means of the jaw clutch 44 at the upper end of the shaft 43 the vertical shaft 43 may be connected in driving relation to the sprocket 35, sothat when the motor 22 is operated power will be transmitted to drive the endless cutter chain on the cutter bar 30. That is to say, when the clutch 44 is thrown in and the motor 22 operated the chain kerf-cutter may be driven through the sprockets 36, 34, sprocket chain'35, torque shaft 33, and sprocket 32.

As shown in Fig. 8 the jaw clutch 44 may be operated by a lever 45 which is connected to a rock shaft journaled in the bracket 46 secured to the underside of the top plate 41. The clutch 44 is accessible for lubrication and repair through the hand hole 48 normally closed by the hinged cover plate 49.

On the upper side of the depending bracket 28 is another top plate 50 whichis in the same plane as the top plate 41. It should be particularly noted that when the ring I! and turntable 26 are adjusted to their lowest positions on the supporting standards l9, l9, I9 the overall height of the entire machine is relatively low thereby adapting the same for use in relatively low-roof mine chambers. Furthermore, during transportation along the low-roof mine entries the top of the machine may occupy such relatively low position because the mechanism hereinafter described enables the adjustment of the chain kerfcutter from the plane of the floor to a plane above that extending through the top of the track l6.

As shown in Fig. 3 the sprocket 32 is secured to the lower end of the tube 5| which is journaled in the bearing 52 on the cutter head 29. Bearings are provided at 53 and 54 for the end portions of the tube 51 so as to confine the latter against vertical movement relatively to the cutter head 29 but permitting free rotation of the tube 5| and the sprocket 32 relatively to the cutter head 29.

The cutter head 29 is supported from a vertically slidable frame 55 which is square in cross section as shown in Fig. 4. The forward portion of the frame 55 is provided with shoes 56, 51 which fit vertical angular guides 58, 59 on the front portion of the depending bracket 28. The rear corners of the frame 55 are provided with laterally projecting journal bearings 69, 6| for the anti-friction rollers 62, 62 which engagevertical wear plates 64, 64 and 65, 65 secured to the vertical trough guides 66, 6! which are fixed rigidly or made integral with the depending bracket 28.

In order to lighten the construction of the frame 55 it may be provided with inwardly projecting spider arms 68, 68 as shown in Fig. 4, the inner ends of which support the ring 10 journaled on to bearing H at the central portion of the cutter head 29. A ring 69 is secured to the bearing 'H by means of the cap screws l2, 12 so as to confine the cutter head 29 against upward or downward movement relative to the frame 55. The cutter head 29 and the chain kerf-cutter are therefore mounted for arcuate adjustment relative to the frame 55 and the cutter head 29 may be held in fixed position relative to the frame 55 by means of a vertically slidable pin 13 which is adapted to fit into any one of the plurality of holes 74 in the cutter head. It should be understood that the pin 13 is slidable through a single opening in the frame 55 and that this opening is adapted to register with any of the plurality of recesses 74 in the cutter head 29.

The connection between the cutter head 29 and the frame 55 is manually releasable by means of the lever 15 journaled on one side of the bracket 28 at I6, 16 and connected by means of the link 15 to the lever 15" which is secured to the rockshaft T! journaled in the bearings 16, 16". Secured to the inner end of the rockshaft 11 is a shipper Tl connected to the vertical sliding pin 13. When the handle 15 is released a spring 18 automatically tends to move the pin downwardly by rocking the shaft Tl back to its initial position. Therefore after the pin has been released manually and the cutter bar 36 has been swung through a small angle, such lever 15 may be released and the spring 18 relied on to snap the pin I3 into the next recess 74 and thus hold the cutter bar 39 rigidly against the swinging movement in either direction relatively to the frame 55 and the depending bracket 28.

The chain kerf-cutter may be adjusted in elevation by means of the nut and screw elements 19 and 89 which are mounted midway between the forward corner shoes 56, 51 on the frame 55. The lower end of the screw element is keyed to the forward portion of the frame 55. The screw element 89 is therefore non-rotatable. The rotary nut element i9 is mounted on ball bearing 8| in the cup shape bracket 82 which is secured rigidly to the bracket 28.

Journaled on the bearing 83 above the nut element [9 is a gear 84 which is concentric with the nut and screw elements l9-and 80.

The extensible torque shaft 33 comprises the upper section 85 which is provided with flutes 36 fitting into and slidable vertically along registering flutes in the upper inner portion of the tubular element 5!. A gear 81 is keyed to the upper end of the fluted section 85 below the ball bearing 88. Therefore when the sprocket 34 is rotated the extensible torque shaft 33 which transmits rotary motion to the sprocket 32 also rotates the gear 81 and in turn effects rotation of the gear 84.

When it is desired to rotate the nut element 19 on the screw element 83 the cone clutch 89 may be thrust downwardly by means of the shipper lever 99 which is pivoted at 9!. By reversing the electric motor 22 on the turntable the armature shaft 48 thereof may be reversed and therefore the nut element [9 may be rotated in either direction to act on the screw element 80 to effect lifting and lowering of the cutter bar 3!]. By placing the nut and screw elements I9 and 86 as far forward as possible between the shoes 56 and 51 the lifting point is brought nearer the center of gravity of the cutter bar 30, cutter head 29, and frame 55, considered as a unit. The anti-friction rollers 62, 62 moving along the vertical trough shaped guides 66, 61 facilitate the vertical adjustment of the cutter bar along the four cornered depending bracket frame 28.

During swinging feeding movement of the cutter bar at an adjusted elevation on the center of the turntable 2f! the twisting strains exerted by the resistance to swinging feeding movement of the cutter bar are eifectively counteracted by the distribution of the guiding mechanism around the center of the torque shaft 33. That is to say, such distribution of the vertical guides 58, 59, 65, 61 about the center of the torque shaft 33 prevents distortion of the bracket frame 28 during swinging feeding movement of the cutter bar into the coal vein and at the same time such guiding mechanism. acts to enable the nut and screw elements 19, ti l to be moved along vertical lines at right angles to the'plane of the cutter bar 3%] and parallel to the axis of the torque shaft 33.

It should be particularly noted that the vertical guides 53, 59 are located in a vertical transverse plane extending through or closely adjacent the non-rotatable vertical screw 8i] and that such vertical guides 53, 59 are closely adjacent the rear end of the effective length of the chain kerf-cutter. Such location of the vertical guides 58, 59 enables them to very emciently resist feeding strains of the kerf-cutter when the latter is fed arcuately on the axis of the turntable.

It should be understood that during swinging feeding movement of the'kerf-cutter the clutch 8 is in released position. In order to assure this, springs (one of which is shown at 93 in Fig. 3) act to release the clutch 89 as soon as the lever on is released. Therefore during swinging feeding movement of the kerf-cutter there willbe no tendency for the nut i9 to be rotated. After the clutch 89 has been released the weight of the kerf-cutter 39, the cutter head 29 and the frame 55 is not supported entirely by the nut and screw elements 79, 30. Secured to front and lateral sides of the frame 55 are horizontal brackets 55, I51 and E58 to the undersides of which are bolted plates one of which is illustratedat I59 in. Fig. 3. These plates are provided with arcuate ledges E89, NH and I82 concentric with the circular flange I83 on the periphery of the cutter headfii and in position to receive such flange and thus cooperate with the nut and screw elements l9, 86 in supporting the kerf-cutter at any adjusted elevation. Such ledges also support the kerf-cutter and the cutter head as when moved arcuately relatively to the frame 55.

During operation of the kerf-cutter, cuttings are prevented from flying against the screw element 8il by means of the guards 94, which are in telescopic relation as shown in Figs. 3 and 4. Such dust as may enter the openings in the sides of the frame 55 may be removed through the openings 96, 9? in the rear and forward bottom portions of the frame 55. V

It should also be noted that the kerf-cutter is adjustable in elevation relative tothe mine bottom not only along the bracket frame-28 but the wheel supported frame I4.

withstanding the fact that the mining machine is transportable along low-roof mine entries the kerf-cutter may have a wide range of adjustments in elevation relative to the mine bottom. For instance, if the adjustment in elevation of the kerf-cutter is approximately 12 inches relative to the bracket frame 28 and 18 inches by means of the turntable relative to the frame I4 the total adjustment of the kerf-cutter relative to the mine bottom will be approximately 30 inches. Nevertheless ;the kerf-cutter may be adjusted to cut at the floor level in low veins and adjusted above the plane of the tops of the rails for transportation from place to place in the mine.

The mechanism for feeding the chain kerfcutter on the center of the turntable may be understood by referring to Figs. 5 to 13 inclusive. The ring I! has secured to its inner edge an annular rack 98 with which meshes a pinion 99 at the lower end of the vertical shaft 38 mounted in a bearing It!!! on the turntable 2i Keyed to the upper end of the shaft 38 is a spur gear In! which meshes with a spur gear I812. By means of a friction disk clutch I83 operated by the sprocket I94, the gear I52 may be connected through the rotating element Hi5 to the vertical shaft I06. To the lower end of the shaft IE5 is keyed a worm gear III? with which meshes a worm. I08 which is arranged to be operated in one direction or the other by means of the pawl and ratchet mechanism. shown in Figs. 6, 9, 10 and 12.

As shown in Fig. '7 a manual wheel I99 is mounted on a shaft IIB the opposite end of which is connected to a bevel gear II! meshing with the bevel gear II2 mounted for rotation on a vertical axis and connected to the sprocket H3; An endless sprocket chain I l t meshes with the sprockets H3 and IM. Therefore by rotating the wheel I09 in one direction or the other the friction clutch I03 may be applied or released to effect connection between the worm I68 and the annular rack 98.

As shown in Fig. 9 the lower end of the shaft 43 is provided with an eccentric cam M5 on the periphery of which is mounted the eccentric strap II6 to which is pivoted at II? the reciprocating arm H8. Pivoted at I I9 to the outer end of the arm I I8 is a bifurcated support 52% carrying the bearing pin IZI as shown in Figs. 9 and 10.

Journaled on pin I2I and on the shaft H38 are supporting members I22, I23 and between these members on the pin I2I are reversely arranged pawls I24, I25. Reversely arranged ratchets I25, I21 are keyed to the shaft IE8 to rotate with the latter. A pawl setting device 528 is provided with openings I28, I28 in position to permit pawl I24 or the other pawl 25 to engage its respective ratchet wheel I26 or I21.

By means of the lever I29 the shaft 539 may be rocked in one direction or the other to oper" ate the spur gearing I3I, I32, to bring either the opening I28 or the opening I28" into position to permit one pawl ILG or the other pawl m5 to engage its ratchet wheel. A spring pressed pin I33 fits into one of the recesses I32 to hold the pawl setting device I28 in adjusted position.

It can readily be seen by referring to Fig. 12 that the positioning of the openings i223, I28" will predetermine the speed of swing of the cutter bar, and that such speed may be relatively slow in one direction for feeding purposes and relatively fast in the opposite direction for restoring purposes.

nected in adjusted position to the turntable 20 Inasmuch as it is desirable to maintain the overall height of the entire machine at a minimum, the reversible feeding mechanism for the kerf-cutter is compactly arranged in a low posi- -tion relative to a horizontal plane extending through the top of the machine shown in Fig. 2. As shown in Fig. 5, the friction clutch is depressed into the space surrounded by the gear I62 so as to be below such horizontal plane and likewise the feeding mechanism shown in Fig. 9 is located well below the horizontal plane of the cover plate 41. The pawl and ratchet mechanism being reversible permits the motor 22 on the turntable to be operated continuously in, the same direction, and such pawl and ratchet mechanism is well adapted to swing the kerf-cutter at a feeding speed in either direction on the axis of the turntable. Furthermore, such pawl and ratchet mechanism being itself reversible enables the use of a single friction clutch I03 for controlling the transmission of power from the vertical shaft I86 to the spaced parallel vertical shaft 38 to effect rotation of the pinion 99 and the travel of the latter along the fixed annular rack 98 to swing the kerf-cutter on the axis of the turntable. The direction of such swinging feed of the kerf-cutter is predetermined by the setting of the lever I29 shown in Fig. 10 and the friction clutch I 93 is applied or released by turning the wheel I09 (Figs. 6 and '7).

At the right hand end of the shaft I08 as shown in Fig. 10 is secured a brake wheel I35 with which is associated a brake band I36 which is held yieldingly applied to the brake wheel I35 by means of the springs I31, I31. During swinging feeding movement of the kerf-cutter into the mine vein, vibrations may cause partial reversal of the worm I88 while the pawl I24 or the pawl I25 is moving from one notch to the next notch. To overcome this tendency of the worm I68 to partially reverse its rotation, the brake mechanism shown at the right hand end of the shaft I08 is relied on to hold the worm I68 in the position to which it had been moved by the pawl ratchet mechanism.

To facilitate assembly or removal of the pawl and ratchet mechanism for replacement of parts, the bracket I38 for supporting the shaft I39 may be removably secured by means of the cap screws .I39 to the turntable 29. The bracket I38 may fit into the trough I46 so as to hold in place the sections I4I, I4I of the bearing for the right hand portion of the shaft I68.

Spaced at intervals around the peripheral portion of the turntable 20 on the underside thereof are brackets I42 in which are mounted fixed vertical bearings I43 for rollers I44 within the rings I45 which are adapted to roll around the inner surface of the ring IT as shown in Fig. 7. Lateral thrust on the turntable will therefore be taken by the roller bearings I43, I44, I45 to relieve the strain between the pinion 99 and the annular rack 98.

It will thus be seen that during swinging feeding movement, the cutter bar 38 is rigidly conand the latter will be guided concentrically of the stationary ring IT by means of the roller bearings shown in Fig. '7, while the power is being transmitted very efliciently from the motor 22 to the pinion 99 to cause the same to travel along the stationary annular rack 98.

The mechanism for supporting and rotating the turntable and the means for controlling such rotation, are described and claimed in my copending application, Serial No. 279,903, filed June 19, 1939, for an improvement in Mining machines.

The clutch 89 for controlling the kerf-cutter elevating mechanism may be applied by means of the manually actuated mechanism shown in Figs. 15 and 16. When the lever I46 is pulled upwardly it will be turned on its horizontal pivot I41 to depress the arm I48, the link I49 and the lever arm I50. The shaft 9I will be rocked in a clockwise direction as viewed in Fig. 16 and in an anti-clockwise direction as viewed in Fig. 3. Consequently the shipper 90 will lower the clutch element 89 to apply the clutch.

Although a plurality of springs 93 distributed about the nut I9 may be relied on to release the clutch element 89 automatically when the lever I46 is released, it may sometimes happen that the clutch will remain applied by friction even after the lever I46 is released. I therefore prefer to automatically release the clutch when the kerf-cutter is moved downwardly and reaches a predetermined limit of travel. For this purpose a chain I5I is connected at its lower end at I5I to the downwardly movable frame and at its upper end the chain is connected through the extension mechanism. I52 to the lever I46 at I53. Such extension mechanism comprises the rod I54, the spring I55 and the spring-retaining tube I56, as shown in Fig. 16. When the lever is pulled up to apply the clutch 89 the spring I55 is partially compressed and when the kerfcutter reaches the predetermined lower limit of its travel the chain I5I and the connections between its upper end and the lever I46, will pull the lever I46 down to release the clutch and prevent the screw 80 from being disconnected from the nut I9.

The operator should let go of the lever I46 as soon as he feels the downward pull being exerted so that the clutch will be released and so as to enable him to again apply the clutch after the motor 22 has been reversed. The upward pull on the lever I46 will then compress the spring I55 to enable the clutch to be applied and cause the power-operated mechanism to lift the kerf-cutter. That is to say, although the kerf-cutter has been automatically stopped at its lower limit of travel the lever I46 by reason of the spring I55 may nevertheless be moved upwardly to apply the clutch 89 to start the kerf-cutter on an upward movement.

However, if the operator holds the clutch applied too long while the kerf cutter is approaching its lower limit of travel the spring I55 will be compressed to such an extent as to positively release the clutch in spite of the operator since lowering of the kerf-cutter is effected by motoroperated mechanism. When this happens there should still be sufficient engagement between the nut and screw elements to support the cutter bar and the parts connected thereto and enable the lifting mechanism to operate. To effect reversal of the cutter bar from its lower limit the chain may be disconnected at I 5I and the clutch 89 applied manually and after the cutter bar has been moved to an upper adjusted position the chain may be re-connected at I5I.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I wish therefore not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

1. In a mining machine, the combination with a truck adapted to travel along a trackway, of

'a radial supporting arm on said truck movable bodily therewith, an overhanging guide support depending from the outer end of said arm, an elongated kerf-cutter, a cutter head for said kerfcutter, a four-cornered guide on said guide support, four-cornered means on said head including a pair of non-friction rollers for engaging said four-cornered guide to adjust said kerf-cutter rectilinearly, and mechanism comprising a single lifting shaft for effecting rectilinear adjustment vertically of said kerf-cutter to horizontal planes.

2. In a mining machine, the combination with a truck adapted to travel along a mine track, of a radial arm secured to said truck to move bodily therewith, an overhanging support depending from the outer end of said arm, an elongated chain kerf-cutter comprising a cutter bar, a cutter head, vertical guides spaced around said cutter head, vertical members including a pair of non-friction rollers spaced around said head in registry with said vertical guides, means spaced substantially midway between a pair of said guides for moving said head vertically while said vertical members move along said guides to adjust the elevation of said cutter bar, the said means :being disposed to prevent tendency of the head to bind in the guides during vertical adjustment of the head, and mechanism for driving said chain kerf-cutter at adjusted elevation. 3. In a mining machine, the combination with a supporting frame, of a kerf-cutter, means comprising a screw for adjusting the position of said kerfcutter, and parallel spacedapart guiding devices two of which are in the same plane as said screw for directing adjustment of said kerf-cut- 'ter relative to said frame along rectilinear lines. 4. In a mining machine, the combination with a supporting frame, of an. elongated chainkerfcutter comprising a cutter bar, a head for carrying said cutter bar for adjustment relative to said frame, means for driving said kerf-cutter comprising an extensible torque shaft located at right angles to the plane of said cutter bar, a pair of guiding devices between said frame and said head in a transverse plane rearwardly of said shaft, another pair of guiding devices in a transverse plane in advance of said shaft, and means in advance of said shaft and parallel thereto in the plane of the forward pair of guiding devices for adjusting said cutter bar along lines at right angles to itself.

5. In a mining machine, the combination with a supporting frame, of an elongated chain kerfcutter comprising a cutter bar, mechanism for driving said kerf-cutter comprising a shaft at right angles to the plane thereof, a head for carrying said kerf-cutter, vertical spaced-apart guides on said frame in a vertical plane rearward of said shaft, anti-friction rollers on said head and movable along said vertical guides, additional vertical spaced-apart guides on said frame in a plane in advance of said shaft, sliding shoes on said head engaging said last-named guides, and means comprising a screw parallel to said shaft and in advance thereof for moving said head along said guides to adjust said kerf-cutter along lines at right angles to itself and parallel to said shaft.

6. In a mining machine, the combination with -a truck, of a main frame and an adjustable supporting frame, cutting mechanism carried by the supporting frame, the said frames being substantially square in cross section, angular guides at eachcomer of the main frame, shoes on each front corner of the adjustable frame adapted to engage the front angular guides, and means for vertically adjusting the adjustable frame including lifting mechanism for the adjustable frame positioned midway between the forward corner shoes thereof.

'7; In amining machine, the combination with a-truck, of a main frame and an adjustable supporting frame, cutting mechanism carried by the supporting frame, the said frames being substantially square in cross section, angular guides at each corner of the main frame, shoes on each front corner of the frame adapted to engage the front angular guides, and means for vertically adjusting the supporting frame including lifting mechanism for the supporting frame positioned midway between the forward corner shoes thereof, the-liftingmechanism including nut and screw elements,.the nut being connected with the screw and the screw with the cutting mechanism, and means for rotating the nut on the screw.

8. In a mining machine, the combination with atruck adapted to travel along a trackway, of a turntable mounted on the truck for adjustment relative thereto on an upright axis, a radial supporting arm on the. turntable movable bodily therewith, an overhanging guide support depending from the outer end of the said arm, an elongated kerf-cutter, a cutter head for the kerfcutter, a four-cornered guide on the guide support, four-cornered means on the head for engaging .the four-cornered guide to rectilinearly adjust the kerf-cutter, and motor operated nut and screw mechanism positioned toward the center of gravity of. the cutter head and kerf-cutter for effecting free rectilinear adjustment vertically of the kerf-cutter to horizontal planes.

I 9.. Inamining machine, the combination with a truck adapted to travel along a track, of a four-cornered. framework supported thereon for rotationarelatively thereto on an upright axis andhaving 9. depending support at its forward end, an elongated chain kerf-cutter, a cutter head for carrying the said kerf-cutter, guideways distributed about the depending support each corner of the frame, vertical shoes on the said cutter head in position to move along the front pair of guideways, anti-friction devices on the cutter head for engaging the rear pair of guideways, means for driving the kerfcutter, means for adjustingthe elevation thereof by adjusting the elevation of the said cutter head, the said means being positioned forwardly of the cuttermheadbetween the said shoes, and means for rotating the said framework to secure swinging feeding movement of the kerf-cutter while the shoes associated with the guideways resist twisting strains on the depending support during feeding of the kerf-cutter.

10. In a mining machine, the combination with a truck adapted to travel along a track, of a four-cornered framework supported thereon for rotation relatively thereto on an upright axis and having a depending support at its forward end, an elongated chain kerf-cutter, a cutter head for carrying the said kerf-cutter, guideways distributed about the depending support each in vertical position and located adjacent each corner of the frame, vertical shoes on the said cutter head in position to move along the front of guideways, anti-friction devices on the cutter head for engaging the rear pair of guideways,

means for driving the kerf-cutter, means for adjusting the elevation thereof by adjusting the elevation of the said cutter head, the said means comprising a screw connected with the cutter head, a nut connected with the screw, and mechanism for intermittently rotating the nut relatively to the screw, the said means being positioned forwardly of the cutter head between the said shoes to minimize tendency of the frame to bind in the guideways during lifting of the cutter head, and means for rotating the said framework to secure swinging feeding movement of the kerf-cutter while the shoes associated with the guideways resist twisting strains on the depending support during feeding of the kerfcutter.

11. In a mining machine, the combination with a truck adapted to travel on a mine track, of a substantially square supporting frame thereon, an elongated kerf-cutter supported on the forward end of the frame for adjustment in elevation relative thereto, means comprising a vertical shaft for driving the kerf-cutter, vertical guiding mechanism including vertical guides adjacent each corner of the frame, wear shoes on the forward corners of the frame for cooperating with corresponding vertical guides, anti-friction rollers at the rear corners of the frame operating in the rear vertical guides, and means'positioned midway between the forward'corner shoes on the frame for elevationally adjusting the kerfcutter. V v v 12. In a mining machine, the combination with a truck adapted to travel on a mine track, of a substantially square supporting frame thereon, an elongated kerf-cutter supported on the forward end of the frame for adjustment in elevation relative thereto, means comprising a vertical shaft for driving the kerf-cutter, vertical guiding mechanism including vertical guides adjacent each corner of the frame, devices on the frame cooperating with the guides for protecting the frame against wear during elevational adjustment ofthe kerf-cutter, and means positioned midway between the forward weareprotecting devices for elevationally adjusting the kerf-cutter, while minimizing tendency of binding between the frame and guides during the elevational adjustment of the kerf-cutter.

13. In a mining machine, the combination with a portableframe, of a support mounted thereon, kerf-cutting mechanism having a head carried by. the support, a motor, a vertical shaft connecting said motor and said cutting mechanism, vertical guiding mechanism forthe kerf-cutting mechanism, means for lifting the said kerf-cut ting mechanism along the said vertical guiding mechanism comprising a vertical shaft extending between said support and said head and spaced forwardly of said first mentioned shaft, and protective means for the lifting mechanism to protect the said mechanism against flying cuttings.

14. In a mining machine, the combination with a portable frame, of a support mounted thereon, kerfcutting mechanism having a head carried by the support, a motor, a vertical shaft connecting said motor and said cutting mechanism, vertical guiding mechanism for the kerf-cutting mechanism, means for lifting the said kerf-cutting mechanism. along the vertical guiding mechanism comprising a vertical shaft extending between said support and said head and spaced forwardly of said first mentioned shaft, and telescopic guards around the lifting mechanism to protect the said lifting mechanism against flying cuttings.

15. In a mining machine, the combination with a main frame, of a supplemental frame mounted thereon for adjustment toward and from the same, a kerf-cutter comprising a cutter bar and chain cutter thereon mounted on said supplemental frame to move bodily therewith, mechanism comprising a single screw located at right angles to the plane of the cutter bar for adjusting the latter toward and from said main frame, parallel spaced-apart guiding devices on opposite sides of said cutter bar in a plane extending at right angles to the cutter bar through said single screw adjacent the rear end of the effective cutting length of the kerf-cutter for directing said cutter bar to various positions in parallelism to each other when adjusted relative to said main frame while said screw and said guiding devices remain in said plane, and means for operating said kerf-cutter in the various positions to which adjusted.

16. In a mining machine, the combination with a main frame, of a supplemental frame mounted thereon for adjustment in elevation relative thereto, a cutter bar mounted on said supplemental frame to move bodily therewith, a chain cutter on said cutter bar, elevating mechanism between said supplemental frame and said cutter bar and comprising a single vertical elevating screw, mechanism comprising four spaced-apart guiding devices on opposite sides of the cutter bar with the two forward guiding devices in a transverse vertical plane extending through said elevating screw for directing said cutter bar into various positions in parallelism to each other when elevated, and means for operating said chain cutter. 7

1'7. In a mining machine, the combination with a main frame, of a supplemental frame mounted thereon for adjustment in elevation relative thereto, a chain kerf-cutter comprising a cutter bar mounted on said supplemental frame to move bodily therewith, mechanism between said frames for effecting adjustment of the cutter bar toward and from said main frame, mechanism comprising two pairs of guiding devices on opposite sides of the forward end of said main frame with the forward pair in a plane extending at right angles to the plane of the cutter bar adjacent to the rear end of the effective cutting length of the kerf-cutter for directing said cutter bar into various positions in parallelism to each other upon operation of the aforesaid adjusting mechanism, and means for operating said chain kerf-cutter in the various positions to which adjusted.

18. In a mining machine, the combination with a support, of cutting mechanism mounted on said support for adjustment in elevation relative thereto, motor-operated mechanism comprising a vertically extensible shaft connected to said cutting mechanism to drive the same, a non-rotatable screw fixed to said cutting mechanism and projecting laterally therefrom, a nut threaded on said screw, a bearing for said nut, a friction clutch having one element loose on said nut and the other element splined thereto, gearing connecting said shaft to said loose clutch element, a plurality of spaced-apart springs between said clutch elements to spread the same apart and hold the clutch released, manual means for applying the clutch and holding the same applied against the action of said springs, and automatic mechanism connected between said cutting mechanism and said manual means to exert suflicient pull on the latter to release the clutch when the cutting mechanism overruns a predetermined limit of travel away from said support.

19. In a mining machine, the combination with a support, of a kerf-cutter, mechanism for adjusting said kerf-cutter toward and from said support, a friction clutch for controlling said adjusting mechanism, resilient means tending to release said friction clutch, manual mechanism for applying said clutch against the action of said resilient means, and a connection between said kerf-cutter and said manual means to exert a pull on the latter to positively release the clutch when said kerf-cutter reaches a predetermined limit of adjustment relative to said support.

20. In a mining machine, the combination with a support, of a kerf-cutter comprising a cutter bar with an endless chain cutter thereon, mechanism for adjusting the cutter bar to various planes in parallelism to each other, a friction clutch for controlling said adjusting mechanism, means comprising a lever pivoted for manual movement toward and from the cutter bar to respectively release and apply the friction clutch, a flexible resiliently extensible connection between said lever and said kerf-cutter to automatically effect a pull on said lever toward said outter bar to release said clutch to limit movement of said kerf-cutter away from said support, said extensibility of said connection enabling manual actuation of said lever to apply said clutch to effect reversal of movement of said kerf-cutter toward said support, and power-operated means for driving said Keri-cutter and for operating said adjusting mechanism.

NILS D. LEVIN.

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