US3288534A

US3288534A - Continuous miner having relatively adjustable transmission housings for boring shafts

Info

Publication number: US3288534A
Application number: US361685A
Authority: US
Inventors: Gonski Joseph
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1964-04-22
Filing date: 1964-04-22
Publication date: 1966-11-29
Anticipated expiration: 1983-11-29

Description

NOW 1966 J. GONSKI 3,288,534

CONTINUOUS MINER HAVING RELATIVELY ADJUSTABLE TRANSMISSION HOUSINGS FOR BORING SHAFTS Flled April 22, 1964 6 Sheets-Sheet l K O T N E V m Joseph 60/2514 J. GQNSKI Nov. 29, 1966 3,288,534 CONTINUOUS MINER HAVING RELATIVELY ADJUSTABLE TRANSMISSION HOUSINGS FOR BORING SHAFTS Filed April 22, 1964 6 Sheets-Sheet 2 2Z5 E 1 m N E Nov. 29, 1966 .1. somsm CONTINUOUS MINER HAVING RELATIVELY ADJUSTABLE TRANSMISSION HOUSINGS FOR BORING SHAFTS Filed April 22, 1964 I 6 Sheets-Sheet 5 INVENTOR. Joseph Gona/ BY L m yframzys J. GONSKI Nov. 29, 1966 3,288,534 CONTINUOUS MINER HAVING RELATIVELY ADJUSTABLE TRANSMISSION HOUSINGS FOR BORING SHAFTS Filed April 22, 1964 6 Sheets-Sheet 4 mo. w: t @H o o E 4 5 i o 5 S aw 8 1hfln a s 3 NE ill, V

UZNEY'S VENTOR.

J. GONSKI Nov. 29, 1966 CONTINUOUS MINER HAVING RELATIVELY ADJUSTABLE TRANSMISSION HOUSINGS FOR BORING SHAFTS Filed April 22, 1964 6 Sheets-Sheet 5 INVENTOR. Joseph ansk/ 9 W mazms NOV. 1966 J. GONSKI 3,288,534

CONTINUOUS MINER HAVING RELATIVELY ADJUSTABLE TRANSMISSION HOUSINGS FOR BORING SHAFTS Flled April 22, 1964 6 Sheets-Sheet 6 INVENTOR, Joseph Gonsk/ United States Patent CONTINUOUS MINER HAVING RELATIVELY AD- JU STABLE TRANSMISSION HOUSINGS FOR BOR- ING SHAFTS Joseph Gonski, Chicago, Ill., assignor, by mesue assignments, to Westinghouse Air Brake Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Apr. 22, 1964, Ser. No. 361,685 13 Claims. (Cl. 299-59) This invention relates to improvements in continuous mining machines of the boring type and more particularly relates to such machines adjustable for mining working places of various widths.

A principal object of the present invention is to provide an improved form of support and drive means for the boring heads of a multiple boring head type of continuous mining machines so arranged as to be adjustable to vary the spacing between the drive shafts of the boring heads and to accommodate the boring heads to mine working places of various widths.

Another object of the present invention is to provide an improved form of continuous mining machine having a plurality of forwardly extending boring heads mounted on power driven shafts, in which the shafts and boring heads are carried by laterally adjustably movable housings, spacing the boring heads in Various selected spaced relation with respect to each other without interfering with the drive to the boring heads.

Another object of the invention is to provide a variable cutting width continuous mining machine having :at least two spaced boring heads in which the boring heads are carried in auxiliary housings movably mounted on the main supporting housing for the machine, for adjustable movement .toward and from the longitudinal center of the machine, :and in which the housings are positively secured in their adjusted positions during a boring operation.

A further object of the invention is to provide a novel and improved form of variable spacing multiple boring head type of continuous mining machine, in which the boring heads are carried on auxiliary housings pivotally mounted on the main supporting housing of the machine, for movement about axes extending longitudinally of the machine and on opposite sides of the longitudinal axis thereof, and in which the shafts supporting and driving the boring heads are eccentric of the axes of pivotal movement of the auxiliary housings, to effect adjustable movement of the boring heads and boring head shafts toward and from the longitudinal center line of the machine, by pivotal movement of the housing about their pivotal axes.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherein:

FIGURE 1 is a fragmentary view in side elevation of the forward end portion of a continuous mining machine constructed in accordance with the principles of the present invention, with certain parts broken away and certain other parts shown in longitudinal section;

FIGURE 2 is a fragmentary view looking at the front end portion of the machine shown in FIGURE 1, with the boring heads removed and certain parts broken away and certain other parts shown in transverse section;

FIGURE 3 is a fragmentary horizontal sectional view taken through the main and auxiliary supporting housings for the machine and showing the gear trains for driving the boring heads, and the mountings for the auxiliary housings on the main housing;

FIGURE 4 is a diagrammatic view schematically illustrating the gear trains for driving the boring heads;

Patented Nov. 29, 1966 FIGURE 5 is a fragmentary front end view of a continuous mining machine, similar to that shown in FIG- URE 1, with certain parts broken away and certain other parts shown in transverse section, and illustrating a modified form in which the invention may be embodied;

FIGURE 6 is a fragmentary horizontal sectional view taken through the main supporting housing and the auxiliary supporting housings of a machine constructed in accordance with the modified form of the invention shown in FIGURE 5;

FIGURE 7 is a diagrammatic view schematically showing the gear train of the form of the invention illustrated in FIGURES 5 and 6; and

FIGURE 8 is a diagrammatic front end view of the main housing and adjustable auxiliary supporting housings for the boring heads of a continuous mining machine, showing still another form in which the invention may be embodied.

In the embodiment of the invention illustrated in FIG- URES 1 through 4 of the drawings, I have shown in FIG- URE l a continuous mining machine of the boring type having a mobile base or main frame 10 and having a cutter frame structure or main supporting housing 11 supported upon and extending in advance of the main frame.

The main supporting housing 11 has auxiliary supporting housings 12 mounted thereon on the outer sides of the center line of the machine for pivotal adjustable movement toward and from the longitudinal center of the machine. Each auxiliary supporting housing has a hub 13 extending forwardly therefrom and forming a bearing support for a boring shaft 15, on ball bearings 16. Each boring shaft 15 has a boring head 17 mounted thereon and rotatably driven thereby.

The boring heads 17 may be of a conventional form, radially adjustable to vary the cutting diameters of the boring heads, .and no part of the present invention, so not herein shown or described further.

The main frame 10 is supported on the usual laterally spaced continuous traction thread devices 1 9, which serve to tram the machine from working place to working place and to feed the boring heads 17 into the mine face. The continuous traction tread devices 19 may be of a conventional form, driven from individual motors and speed reducers (not shown), so not herein shown or described further.

The main supporting housing 11 also forms a support for an upper trimmer or cutter bar 20 extending across .the forward end thereof in rearwardly spaced relation with respect to the boring heads 17, and having a trimmer chain 21 guided for movement therealong, for cutting out the cusps, depending from the mine roof between the boring heads. The trimmer bar 20 is mounted on the usual hydraulic jacks 23, mounted on the forward end of the main supporting housing 11 and extending vertically of said main supporting housing and positioning the upper trimmer bar 20 behind the boring heads 17 and forwardly of the main supporting housing 11.

A lower trimmer bar 24 extends across the forward end portion of a frame structure 25 for the receiving end portion of the conveyor of the machine (not shown) and is suitably supported thereon. The conveyor may be of a conventional form and may extend along the main frame 10 from a position adjacent the ground in advance of the forward end of said main frame, along and beyond the rear end thereof.

The conveyor frame structure may be raised by suitable hydraulic jacks (not shown) to clear the ground and also raises the lower trimmer bar 24 when the conveyor is raised, when it is desired to tram the machine from working place to working place.

The trimmer chain 21 is trained about corner sprockets 26 at opposite ends of the upper trimmer bar 20 and downwardly and inwardly therefrom, one run of said chain being trained about a drive sprocket 27 and the other run ,of said chain being trained about an idler sprocket (not shown) in a conventional manner. From thence the chain is trained outwardly about

corner sprockets

29, 29 at opposite ends of the lower trimmer bar 24.

The main supporting housing 11 is supported adjacent the forward end of the main frame ona pair of laterally spaced independently operable

hydraulic jacks

30, 30. The

hydraulic jacks

30, 30 may be of a conventional form and are mounted on a rear wall of the main supporting housing 11 and extend vertically therealong and are shown in FIGURE 1 as having

shoes

31, 31 engaging the top surfaces of

support blocks

32, 32, for limited angular movement with respect thereto.

The side thrusts of mining are taken by a pair of laterally spaced vertically extending

thrust bars

33, 33, mounted on the rear end of the main supporting housing and depending therefrom. The

thrust bars

33, 33 extend along the insides of

side thrust shoes

35, 35 and limit lateral movement of the housing 11 and thereby take the side thrusts of mining on said housing. The main supporting housing 11 also has parallel spaced arms 36, 36 extending rearwardly therefrom and connected together at their rear ends by a connector plate 37. The plate 37 is mounted on a universal thrust transmitting joint 39 at the longitudinal center of the machine, beneath the conveyor of the machine, which takes the thrusts of mining along the longitudinal center of the mining machine. The universal joint 39 and thrust transmitting structure between the arms 36 and said universal joint may be of a form similar to that shown and described in the Newton et al. application Serial No. 154,961 filed November 27, 1961, and

entitled, Continuous Mining Machine, and now Patent No. 3,208,797 dated November 27, 1965.

Each arm 36 forms a support for a motor 40, extending along the inside thereof and rearwardly beyond the rear end thereof. Each motor 40 has a motor shaft 41 having a universal joint 42 on the end thereof and driven therefrom and driving a spaced universal joint 43 through an extensible shaft 44. The

universal joints

42 and 43 may be of any well known form and serve to drive a drive shaft 45, journalled in the auxiliary housing 12 on spaced bearings 46, in the various positions of said auxiliary housing with respect to the motor 40.

The two auxiliary housings 12 are of a similar construction and the drive gearing journaled therein and driving the boring heads 17, is the same for each boring head so one only need herein be shown or described in detail.

The main supporting housing 11 has a transversely extending front wall 48 having parallel rearwardly extending side walls 49, extending rearwardly from its opposite ends, to a back wall 52 forming supports for the bearings for the gearing journaled within said housing. The back wall 52 is abutted by a closure plate 50 for said main supporting housing. The plate 50 extends beyond opposite sides of the back wall 52 and has vertically extending arcuate slots 62 therein to receive the universal joints 43 and shafts 45 driven thereby.

The front wall 48 has spaced hollow bosses 51 extending forwardly therefrom, each of which hollow bosses forms a pivotal mounting for an auxiliary housing 12, and has a connecting shaft 53 extending therethrough, coaxial with the axis of adjustable movement of the associated auxiliary housing. The connecting shafts 53 serve to connect the drive gearing for driving the two boring heads together, through a gear train 55.

The auxiliary housings 12 are abutted at their forward ends by a front plate 56 extending across the front of the main supporting housing 11 and auxiliary housing 12 and spaced from and secured to the main supporting housing 11 as by parallel spacer walls 57 extending forwardly of the front wall 48 along opposite sides of a drive shaft 59 for the sprocket 27 and suitably driven by the gear train 55. Cap screws 60 are shown as being provided to secure the front plate 56 to the spacer plates 57, and to the main supporting housing 12.

The back plate 50 is suitably secured to the main supporting housing 11 and serves to retain the auxiliary housings 12 in position when in the proper position of adjustment to retain their boring heads in position to mine at a selected width. As shown in FIGURE 3, machine screws 61 are provided to retain the auxiliary housings to said closure plate when in the proper adjusted relation With respect to the main supporting housing 11.

The front plate 56 is secured to the main supporting housing 11 by the machine screws 60 and is secured to the auxiliary supporting housings 12 when in a selected position, by machine screws 63, it being understood that threaded holes are provided in the auxiliary supporting housings 12 to correspond to the various cutting widths of the machine. The front plate 56 has arcuate slots 65 therein for receiving the hubs 13 of the auxiliary housings 12, and accommodating adjustable movement of the boring heads 11 about the axes of the connecting shafts 53.

The auxiliary housings 12 have flanged portions 66 extending radially of the hubs 51 along the outside of the wall 48, which may be secured to said wall, as by machine screws 67. The machine screws 67 are registrable with threaded drilled holes in the wall 48 corresponding to the various positions of lateral adjustment of the boring heads with respect to the longitudinal center of the machine.

The drive connection from each universal coupling 43 and shaft 45, driven therefrom, includes a spur gear 69 on the end of the shaft 45, meshing with and driving a spur gear 70 on the rear end of a longitudinal shaft 71. The shaft 71 has a spur pinion 72 keyed or otherwise secured thereto and meshing with and driving a spur gear 73 on a longitudinal shaft 75. The longitudinal shaft 75 has a spur pinion 76 keyed or otherwise secured to the forward end thereof, meshing with and driving, a spur gear 77 keyed or otherwise secured to the rear end portion of a drive shaft 15- for a boring head 17. The spur gear 77 in turn meshes with .a spur pinion 78 on the forward end of a connecting shaft 53, for driving said connecting shaft and tying the two boring heads together to rotate at the same rates of speed.

When it is desired to vary the cutting width of the machine, the machine screws 61 connecting the back plate 50 to the auxiliary housings 12 may first be rem'oved. The front plate 56 may then be removed to afford access to the machine screws 67. These machine screws may then be removed. The auxiliary housings are now free to pivot about the bosses 51 and may be moved about said bosses to space the axes of the boring head shafts 15 in the proper spaced relation, to position the boring heads 17 to bore at a selected width. The auxiliary housings then being in the proper positions, may be retained in these positions by machine screws 61 and 67.

' The front plate 56 may then be replaced. Thetwo boring heads 17 may thus be driven from the motors 40 and universal couplings 43 in their positions of adjustment about the axesof the connecting shafts 53.

' In the embodiment of the invention illustrated in FIG- URES 5, 6 and 7, the motors are fixedly secured to the main supporting housing and primary gear reduction trains driven by the motors are journalled in the main supporting housing. Secondary or final geared reduction trains are journalled in the auxiliary housings, which also form bearing supports for the boring heads 17.

In this form of the invention the machine is generally similar to that shown in FIGURE 1 except for the structure and arrangement of the main supporting housing and the auxiliary supporting housings. The structure of the main and auxiliary supporting housings together with the geared drive trains therein, therefore, need only be described in detail. The same part numbers will also be applied to the boring heads, the boring head drive shafts, upper and lower trimmer bars, trimmer chain and hydraulic jacks for supporting the upper trimmer bar, as were applied to the same parts in FIGURES 1, 2 and 3.

In FIGURES 5 and 6 I have shown a main supporting housing 111 having auxiliary supporting housings 112 adjustably mounted thereon and having

hubs

113, 113 extending forwardly therefrom and forming bearing supports for boring shafts 115. The hubs and shafts extend through

arcuate slots

114, 114 in a front plate 109 for the main supporting housing. The front plate 109 abuts opposite side walls 116 of the main supporting housing 111, and is secured thereto as by

machine screws

117, 117.

Individual motors 118, 118 are suitably mounted on and extend rearwardly of the main supporting housing 111 and have motor pinions 119 on the ends of motor shafts 120 and driving spur gears 121 on individual longitudinally extending shafts 122 of primary reduction gear trains. Each shaft 122 has a spur pinion 123 thereon, meshing with and driving a spur pinion 123a on a shaft 123b. A pinion 123a on the shaft 123b meshes with and drives a spur gear 124 on a connecting shaft 125. The connecting shafts 125 in turn are connected together by a timing gear train 126 meshing with the spur gears 124. Each shaft 125 extends through a hollow boss 127, coaxial with the center thereof, and has a spur pinion 129 on its forward end, meshing with and driving a spur gear 130 on the boring head support and drive shaft 115. A primary reduction train is thus journalled in the main supporting housing 111 and drives connecting shafts 125, and the secondary or final reduction train is driven from the primary gear train through the connecting shafts 125, and serves as a drive for the associated boring head. The final reduction trains are tied together by the spur gear train 126.

In this form of the invention the auxiliary housings 112 are retained in position by cap or machine screws 133 (FIGURE 5) extending through selected drilled holes 135 in the front plate 109 in accordance with the position of the auxiliary housing with respect to the main supporting housing, and threaded in registering threaded holes in the main supporting housing,

It may thus be seen that in this form of the invention the motors and primary gear trains are carried by the main supporting housing and the final geared reductions for driving the mining heads are in the adjustable auxiliary supporting housings, which also adjustably support the mining heads to mine working places of varying widths.

In FIGURE 8 I have diagrammatically shown still another form in which the invention may be embodied. In this form of the invention I have shown a main supporting housing 211 and

auxiliary housings

212, 212 mounted on the main supporting housing 211 for adjustable movement about the axis of rotation of a central drive gear 213. The drive gear 213 may be driven from the single motor (not shown) suitably mounted on the main supporting housing 211 for driving the gear 213 through a suitable reduction train housed in the main supporting housing 211. Auxiliary housings 212 form bearing supports for

drive shafts

215, 215, supporting and driving boring heads 17 in a manner similar to that disclosed in FIGURES 1 through 7. The gear 213 drives the shafts 215 through a gear train 216, journalled in one auxiliary housing 212, and a gear train 217 journalled in the other auxiliary housing 212. The gear trains 216 and 217 have the same reduction, but the gear train 216 has a reversing gear therein to drive the shaft 215 in an opposite direction from the shaft 215 driven through the gear train 217, and thus to effect a drive to the two boring heads 17 in opposite directions and in directions to progress the mined material toward the center of the machine, to be picked up by the conveyor of the machine (not shown).

In this form of the invention the auxiliary supporting housings 212 may be held in the desired positions of ad.-

justment by cap or machine screws (not shown) as in the form of the invention illustrated in FIGURES 2, 3, 5 and 6, or by any other suitable holding means. Lateral adjustment of the boring heads is thus along the broken arcuate lines A, shown in FIGURE 8 as being struck from axes coaxial with the axis of rotation of the gear 213.

While I have herein shown and described one form in which the invention may be embodied, it may readily be understood that various variations and modifications in the invention may be attained without departing from the spirit and scope of the novel concepts thereof.

I claim as my invention:

1. In a variable spacing multiple boring head assembly and in combination with a continuous mining machine, a main supporting housing, a plurality of parallel boring shafts supported by said main supporting housing, at least one auxiliary housing carried by said main supporting housing for pivotal adjustment about an axis parallel to one of said boring shafts, means detachably holding said auxiliary housing in adjustment with respect to said main housing said one boring shaft being carried by said auxiliary housing, transmission means carried by said main supporting housing for driving said boring shafts simultaneously including a connecting shaft extending between the main and auxiliary housings and journalled for rotation about the axis of pivotal adjustment of said auxiliary housing whereby the position of said one boring shaft on the main supporting housing can be varied by pivotally adjusting said auxiliary housing about said connecting shaft.

2. In a variable spacing multiple boring head assembly and in combination with a continuous mining machine, a main supporting housing, a pair of auxiliary housings mounted on said main housing for pivotal adjustable movement respectively about a pair of parallel spaced axes, means adjustably holding said auxiliary housings in adjusted relation with respect to said main supporting housing, each auxiliary housing carrying a boring shaft eccentric of and parallel to the corresponding axis, transmission means in said main and auxiliary housings for driving said boring shafts simultaneously including a pair of connecting shafts extending from said main housing respectively into said auxiliary housings and respectively journalled for rotation about said parallel axes whereby the spacing between the boring shafts may be varied while maintaining them both at the same level with respect to one another by similarly pivotally adjusting said auxiliary housings about the axes of their respective connecting shafts.

3. In a continuous mining machine, a mobile main frame, a main supporting housing mounted on said main frame and extending in advance thereof, a pair of laterally spaced rotary boring heads, support means for said boring heads supporting said boring heads on said main supporting housing for adjustable movement toward and from the longitudinal center of the machine including a pair of auxiliary supporting housings, each having a boring shaft journalled therein supporting and driving a rotary boring head and containing reduction gearing for driving said boring shaft, a fixed motor in association with each auxiliary housing, a universal drive connection from each motor to the reduction gearing in the associated auxiliary supporting housing accommodating adjustable movement of said auxiliary supporting housing with respect to the associated motor, connecting gearing journaled in said main sup orting housing connecting said boring shafts for rotation together and including connecting shafts driven by the reduction gearing contained in said auxiliary housings, pivotal mountings for said auxiliary housings on said main supporting housing coaxial with the axes of rotation of said connecting shafts and means securing said auxiliary housings in adjusted relation with respect to each other about said pivotal mountings.

4. A continuous mining machine in accordance with claim 3 wherein the main supporting housing has hollow bosses extending forwardly therefrom having exterior cylindrical wall portions coaxial with the axes of rotation of said connecting shafts and forming pivotal mountings for said auxiliary supporting housings.

5. A continuous mining machine in accordance with claim 3 wherein the means securing said auxiliary housings in fixed relation with respect to said ma'n housing includes a plate extending across the front of said main and auxiliary housings and secured to said main supporting housing and having slots therein in registry with said boring shafts and accommodating adjustable movement of said shafts, and includes securing means securing said auxiliary housings to said plate.

6. A continuous mining machine in accordance with claim 5 wherein the securing means securing said auxiliary housings in adjusted relation with respect to said main housing includes front and back end plates for said main supporting housing secured thereto and extending beyond opposite ends thereof along said auxiliary housings, wherein the back plate has slots therein for the universal drive connections, accommodating adjustable movement of said auxiliary housings with respect to said drive motors, wherein the front plate has slot therein accommodating adjustable movement of said boring shafts and front housings with respect to said front plate and wherein separate securing members extending through said front and back plates and registrable with said auxiliary housings are provided to retain said auxiliary housings in adjusted relation with respect to said main supporting housings.

7. In a continuous mining machine, a mobile main frame, a main supporting housing mounted on said main frame and extending in advance thereof, a pair of auxiliary housings mounted on said main supporting housing for pivotal adjustable movement respectively about a pair of spaced parallel axes, means holding said auxiliary housings in adjusted relation with respect to said main supporting housing, each auxiliary housing carrying a boring shaft eccentric of and parallel to the corresponding parallel axis, transmission means in said main and auxiliary housings for driving said boring shafts simultaneously at the same rates of speed including a pair of connecting shafts extending from said rnain supporting housing respectively into said auxiliary housings and respectively journaled for rotationabout said parallel axes, whereby position of said one boring shaft on the main supporting housing can be varied by pivotally adjusting said auxiliary housing about said connecting shaft and securing said auxiliary housing in a selected position of adjustment.

9. The combination of claim 8 in which the finalspeed reducing gearing includes speed reducing gearing for connecting the boring shaft to one power source, one gear of which is meshed with a gear of said connecting shaft, the latter having an additional gear adapted to be connected to another power source to render both of said power sources effective for driving said boring shaft.

1%). The combination of claim 8 in which each connecting shaft interconnects one corresponding set of initial and final speed reducing gearing and wherein connecting gearing is provided and extending across said main supporting housing for interconnecting said connecting shafts for rotation simultaneously with one another to correlate the rotation of said boring shafts.

11. In a continuous mining machine, a mobile main frame, a main supporting housing mounted on said main frame and extending in advance thereof, a pair of auxiliary housings mounted on said main supporting housing for pivotal movement respectively about a pair of spaced parallel axes, means adjustably holding said auxiliary housings in selected positions of adjustment with respect to said main supporting housing, each auxiliary housing carrying a boring shaft eccentric to and parallel to the corresponding axes and each boring shaft supporting and driving a rotary boring head, transmission means in said main and auxiliary housings for driving said boring shafts simultaneously including a pair of connecting shafts extending from said main supporting housing respectively into said auxiliary housings and respectively journaled for rotation about said parallel axes, one set of gearing for driving said one of said boring shafts from one power 7 source and another set of gearing for driving the other said boring shafts extend forwardly from said auxiliary housings in a horizontal direction and the spacing between the boring shafts may be varied while maintaining said boring shafts both at the same level with respect to one another by similarly pivotally adjusting said auxiliary housings about the axes of the respective connecting shafts, and wherein the connecting shafts are disposed at the level above and at lease as close to the center of the main supporting housing as its corresponding boring shaft whereby the level of the two boring shafts is automatically elevated as their spacing is increased by simultaneously pivotally adjusting said auxiliary housings.

8. In a continuous mining machine, a mobile main frame, a main supporting housing mounted on said main frame and extending in advance thereof, a plurality of parallel boring shafts having boring heads supported thereon and rotatably driven thereby, supported by said main supporting housing, an auxiliary housing mounted on said main supporting housing for pivotal adjustment about an axis parallel to said one shaft and spaced therefrom, at least one of said shafts being carried by said auxiliary housing and means holding said auxiliary housing in adjusted relation with respect to said main housing, transmission means carried by said main supporting housing for driving said boring shafts simultaneously including initial speed reducing gearing and a connecting shaft extending between the main and auxiliary housings and journaled for rotation about said axis and interconnecting said initial and final speed reducing gearing, whereby the boring shaft from another power source, said connecting shafts each having a first gear meshedv with a respective set of said gearing and having a second gear means extending across said main supporting housing and interconnecting said first gears with one another, whereby both power sources are connected to drive both boring shafts simultaneously and the power of both sources will be applied automatically to either boring shaft as needed, and whereby the spacing between the boring shafts may be varied while maintaining them both at the same level with respect to each other by similarly pivotally adjusting said auxiliary housings about the axes of their respective connecting shafts and fixedly securing said auxiliary housings in their selected positions of adjustment.

12. A variable spacing multiple boring head according to claim 11 in which each of the connecting shafts is disposed at a level above and at least as close to the center of the main supporting housing as its corresponding boring shaft, whereby the levels of the'two boring shafts are automatically elevated as their spacing is increased by simultaneously pivotally adjusting said auxiliary housings.

13. A variable spacing multiple boring head continuous mining machine in accordance with claim 12 wherein spaced front and back plates for said main supporting housing extend along said auxiliary housings and have slots therein to accommodate adjustment of said auxiliary housings with respect to said main supporting housing and form a means for securing said auxiliary housings in fixed relation with respect to said main supporting housing.

References Cited by the Examiner UNITED STATES PATENTS 2,694,563 11/1954 Graham 299-59 2,761,664 9/1956 Bowman 299-59 2,878,001 3/1959 Snyder et al. 299-59 3,013,784 12/1961 Osgood 299-60 ERNEST R. PURSER, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO 3 288 ,534 November 29, 1966 Joseph Gonski It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 51, for "housing" read housings column 5, line 68, for "dircetion" read direction column 7, line 53, for "lease" read least line 71, after "gearing" insert final speed reducing gearing,

Signed and sealed this 12th day of September 1967.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents