US1387886A - Coal-mining machine - Google Patents
Coal-mining machine Download PDFInfo
- Publication number
- US1387886A US1387886A US1387886DA US1387886A US 1387886 A US1387886 A US 1387886A US 1387886D A US1387886D A US 1387886DA US 1387886 A US1387886 A US 1387886A
- Authority
- US
- United States
- Prior art keywords
- coal
- platform
- machine
- undercut
- conveyer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000005065 mining Methods 0.000 title description 11
- 239000003245 coal Substances 0.000 description 61
- 238000005422 blasting Methods 0.000 description 6
- 230000033001 locomotion Effects 0.000 description 6
- 238000010276 construction Methods 0.000 description 4
- 210000000481 breast Anatomy 0.000 description 3
- 238000003776 cleavage reaction Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000007017 scission Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000000881 depressing effect Effects 0.000 description 1
- 230000010006 flight Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C25/00—Cutting machines, i.e. for making slits approximately parallel or perpendicular to the seam
- E21C25/68—Machines for making slits combined with equipment for removing, e.g. by loading, material won by other means
Definitions
- the object of this invention is to provide a machine of improved construction for undercutting and for removing the overhanging or undercut breast of coal as the undercutting proceeds, as distinguished from the present method of undercutting and removing the machine before dropping and loadingthe'coal.
- the invention is embodied in a machine wherein a vertically shallow platform supports the undercutting means and upon which the undercut coal is adapted to be dropped either while the undercutting means is operating or at a standstill, as may be preferred, together with conveyer means for receiving the coal from the platform and delivering it directly to pit cars or wagons for removal from the mine. Practically the entire operation of mining is thus performed by one and the same machine, with such complete operation proceeding as rapidly as the coal is undercut, thereby eliminating many of the operating steps heretofore necessary and correspond ingly decreasing the expense of and expediting the work. I
- the invention includes a coal delivering conveyer of improved construction for receiving coal dropped on the undercut-entering platform; also mechanism of improved construction carried by the platform for moving the dropped coal to position to be taken up by said conveyer.
- the delivery conveyer is preferably arranged at an upward incline and with the point of delivery located in the highest portion thereof and at sufficient elevation to drop the coal into a pit car or wagon located therebeneath.
- Figure 1 is a side elevation of the improved machine shown-inoperative position
- Fig. 2 is a view in top plan of the same.
- Fig. 3 is a longitudinal section of the machine taken on line 3-3 of Fig. 2.
- Fig. 4 is a crosssection of the platform-forming forwardportion of the machine taken on line l4- of Fig. 2.
- Figs. 5 and 6 are sectional views on a larger scale illustrating the conveyer undercutting proceeds.
- Fig. 7 1 s a detail view, illustrating the vertical adjustment for the ground wheels.
- 2 designates the horizontal platform-forming forward port on of the portable frame which is relatively shallow vertically in order that it may freely enter an undercut A in the breast of coal B.
- the platform may be constructed of top and bottom horizontalplates 3 and 1, respectively, which are separated by and secured to the girder-like spacing bars 5.
- the rear portion of the platform portion 2 is defincd by the relatively heavy girder 6 which extends transversely of the frame from side to side and depending therefrom and formmg the transverse shoe-like support 7.
- the latter is flanged rearwardly at 8 and secured thereto is the horizontal part 9 of the rearward portion of the frame, the latter having an upward offset at 10 whereby the rearmost portion 11 of the frame is spaced above the mine floor 0, Fig. 3.
- Frame part 11 is provided at its rear with the floor en gaging Wheels 12, and the mountings for these wheels are vertically adjustable as indicated at 13. By means of this adjustment the angle of undercut A is determined, the machine frame being adapted to rock on shoe 7 upon adjusting wheels 12, thereby raising 01 depressing the forward portion of the platform in accordance with the de sired angle of the undercut.
- the forward edge of platform 2 provides a guid'eway for the endless undercutting chain 15, the chain passing around suitable idlers 16 at the front and side of the platform and rearwardly therefrom around the chain-driving wheel 17, the latter being geared to an electric motor 18 supported by the frame part 11.
- This motor is also geared at 19 to the axle 12 of floor wheels 12, whereby the machine is advanced as the Wheels 12 are suitably ribbed or roughenedto obtain the necessary traction, the forward portion of the machine sliding on the under face of platform 2 and on shoe 7, as will be understood.
- the portion of platform 2 which defines the path of the chain cutter may be of any preferred shape or outline. As here shown, it is substantially V-shaped with its apex or angle at the longitudinal center of the machine, whereby a cut of correspondmg form 7 open as shown for i
- the rear ends of bars is had, the tendency of which is to hold the machine in a straight-ahead course.
- the chain cutter 15 is of the type usually employed for undercutting, and for which n novelty is claimed.
- the top plate 3 of platform 2 is slotted at 20, the slots being; disposed in the direction of movement of: the frame and adapted to project through each slot is a toothed bar 21, the tree forward end 01" which slides on bottom plate t between the spacing ⁇ ; bars 21 are secured to cranks 22 of a shaft 23, the latter journaled in the several spacing bars 5 and extending from side to side or" the plattorm between plates 3 and 4:.
- Crank shat 28 may be connected by the worm gearing 24 with the rearwardly extending she-it 25, the latter being geared at 26 to shaft 27 of electric motor 28 mounted on the rearward portion 11 of the frame.
- each bar rear portion traveling in a circular the front end reciprocating back and 1" on plate 4, shaft 23 moving clo k-wise in Fig. 5.
- the toothed tare or each bar is housed at one time and another time is exposec, the exposed portion of travel being in a direction to raise lumps of coal and carry them rearwardly to depositing point, whereupon bar passes below the top plane of plate 8 and moves forwardly while thus housed.
- This provides an intermittent feed of the coal rearwardly, the slow speed tending to prevent brealcing up of coal lumps and at the time carrying the remaining portions of the coal rearwardly into the conveyor.
- the conveyor trough, way or channel is oi: trangular form with one leg thereof paralleling; the rear side ct platform 2 and with the other less 31 and 32 int-lined upward y from the ends of leg 30 and conver the highest point 33 where the trruo'h is into elesaid k the coal a pit car 34: positioned be ath the vated rear end of the conveyor frame, elevated portion being supported by rights 35 rising from trame part 11.
- each leg, o 'f the conveyor trough is formed of a channeled bar and with the conveyor flights 8S fit the rough as clearly shown i- 5, each flight preferably having an entension 88 which travels over the top edge of bar 36 thereby broadening the transverse the drawings the floor or oottom or" each leg consists of a plate of requisite form.
- a substantially triangular open-top trough or way is provided, each angle of which is a wheel 40 for directing t e conveyer chain 37, the wheel the uppermost rear angle being geared to motor shaft 27 shown in Fig. 6 whereby the conveyor is propelled by motor 28.
- both the endless conveyor and the platform eon veyer bars 21 may be actuated by the same motor.
- the machine is positioned for making the undercut and after the an oi the latter has been determined by adjusting the floor wheels 12 tie chain cutt r is set in motion, and y the same motor means the machine is moved forward through the medium of: fl or wheels 12.
- pla ,rm 2 is advanced beneath th breast 01 coal B along with the cutter chain and after an undercut oi sufiicient depth has been attained, he overhangi119, coal B may be dropped by blasting, or other suitable means onto platform 2.
- the machine may have a width equal 'to the width of the room, such width depending to a considerable extent on the strength of the roof, etc, andmay range from eight to sixteen feet.
- the ability to use a machine of this width is brought about by the fact that the coal is not dropped directly upon the conveyer but upon a platform in advance of the conveyer, which platform has a front to rear length sufficient to receive the coal which is dropped, either by use of light blasts or by wedging, and from which platform the coal is moved rearwardly onto the conveyer at a relatively slow speed which will not tend to break up the lumps. Consequently, the conveyer may have its receiving flight equal to the width of the machine and extend transversely of the machine, thus enabling the coal which is fed to the flight to be carried away with sufficient rapidity as to prevent choking of the conveyer system.
- This front to rear length of the platform is generally suflicient to permit the cutter chain to out past the first complete cleavage or face without bringing the transverse conveyer flight in the path of the falling coal, the result being that the coal above the undercut can be brought down by the use of light charges or by a wedging, operations which tend to preserve the lump character of the coal and produce a product of greater value.
- the toothed bars may then be brought into operation to slowly feed the coal toward the conveyer flight, this operation serving the additional purpose of tending to maintain the machine in its forward position so that the cutting operation may proceed concurrently with this feed movement, the bars thus aiding wheels 12 in advanc'ing the machine.
- the operation is substantially continuous, the slow advance of the machine being compensated for by the large quantity of coal which is being worked upon, this slow advance affording the operators sufficient time to provide the drill holes or produce the wedging action. Since the machine is of a type which will permit of taking advantage of the natural cleavage in the coal seams, the blasting charges may be light, since there is no necessity for driving the coal rearward into the mining chamber, it being necessary only to sufficiently release the coal and drop it upon the receiving platform.
- a horizontal vertically shallow coal receiving platform undercutting means mounted below the upper face of said platform and adapted upon the forward movement of said platform to form an undercut
- an endless conveyer movable across and arranged to convey coal from said platform and to carry the same to a point above and in the rear of said platform, and reciprocating means protruding through said platform for moving coal from said undercutting means to said endless conveyer.
- endless undercutting means In a mining machine adapted for use for coal blasting operations, endless undercutting means, a coal supporting frame of Vertically shallow depth arranged in the rear of said undercutting means and constructed to project into the undercut and to receive the coal blasted from above the undercut, reciprocating means, mounted substantially throughout the width of said frame, for moving coal thereon to the rear thereof, and an endless conveyer for carrying the coal from said coal moving means to a point above and to the rear of the machine.
- a coal receiving platform of such height as to be capable of projecting into an undercut, endless undercutting means movable around the forward edge of said platform, an endless conveyer in the rear of said platform, and reciprocating coal moving means between said undercut ting means and said endless cover.
- a frame adapted to enter a horizontal undercut and provided with a central, forward apex, rearwardly inclined edges extending from said apex and rearwardly extending sides at the nism adjacent said zone but not intruding ends of said inclined edges, undercutting thereon.
- 10 mechanism mounted on said frame and In testimony whereof I afiix my signaadapted to operate along the above menture in presence of two witnesses.
- said frame THOMAS DONOHOE. having a platform bounded by said apex, witnesseses: edges and" sides and provided with a coal- J. M. NESBIT,
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
Description
T. DONOHOE.
COAL MINING MACHINE.
APPLICATION FILED OCT. I8, 1915.
Patented Aug. 16, 192 1.
2 SHEETS-SHEET F'IG.1.
l 'I 'I "I ENTOR WITNESSES T. DONOHOE.
COAL MINING MACHINE.
APPLICATION FILED OCT. 18., m5.
11 2 mm M f m 1 w m m m 1 Ow A w C Z v m m w P m r F H 6 8 a 7 a 1,
UNITED STATES PATENT OFFICE.
j THOMAS DONOHOE, OF EDGEWOOD, PENNSYLVANIA.
COAL-MINING MACHINE.
To all to ham it may concern: Be it known that I, THOMAS DONOHOE, a citizen of the United States, and resident of Edgewood, inthe county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Coal- Mining Machines, of which the following is a specification.
The object of this invention is to provide a machine of improved construction for undercutting and for removing the overhanging or undercut breast of coal as the undercutting proceeds, as distinguished from the present method of undercutting and removing the machine before dropping and loadingthe'coal.
The invention is embodied in a machine wherein a vertically shallow platform supports the undercutting means and upon which the undercut coal is adapted to be dropped either while the undercutting means is operating or at a standstill, as may be preferred, together with conveyer means for receiving the coal from the platform and delivering it directly to pit cars or wagons for removal from the mine. Practically the entire operation of mining is thus performed by one and the same machine, with such complete operation proceeding as rapidly as the coal is undercut, thereby eliminating many of the operating steps heretofore necessary and correspond ingly decreasing the expense of and expediting the work. I
The invention includes a coal delivering conveyer of improved construction for receiving coal dropped on the undercut-entering platform; also mechanism of improved construction carried by the platform for moving the dropped coal to position to be taken up by said conveyer. The delivery conveyer is preferably arranged at an upward incline and with the point of delivery located in the highest portion thereof and at sufficient elevation to drop the coal into a pit car or wagon located therebeneath.
In the accompanying drawings, Figure 1 is a side elevation of the improved machine shown-inoperative position, and Fig. 2 is a view in top plan of the same. Fig. 3 is a longitudinal section of the machine taken on line 3-3 of Fig. 2. Fig. 4 is a crosssection of the platform-forming forwardportion of the machine taken on line l4- of Fig. 2. Figs. 5 and 6 are sectional views on a larger scale illustrating the conveyer undercutting proceeds.
Specification of Letters Patent. Patented A g. 16, 1921 Application filed October 18, 1915. Serial No. 56,372.
bars and bar actuating mechanism for moving the coal on the platform in position to betaken up by the delivery conveyer. Fig. 7 1s a detail view, illustrating the vertical adjustment for the ground wheels.
Referring to the drawings, 2 designates the horizontal platform-forming forward port on of the portable frame which is relatively shallow vertically in order that it may freely enter an undercut A in the breast of coal B. The platform may be constructed of top and bottom horizontalplates 3 and 1, respectively, which are separated by and secured to the girder-like spacing bars 5. The rear portion of the platform portion 2 is defincd by the relatively heavy girder 6 which extends transversely of the frame from side to side and depending therefrom and formmg the transverse shoe-like support 7. The latter is flanged rearwardly at 8 and secured thereto is the horizontal part 9 of the rearward portion of the frame, the latter having an upward offset at 10 whereby the rearmost portion 11 of the frame is spaced above the mine floor 0, Fig. 3. Frame part 11 is provided at its rear with the floor en gaging Wheels 12, and the mountings for these wheels are vertically adjustable as indicated at 13. By means of this adjustment the angle of undercut A is determined, the machine frame being adapted to rock on shoe 7 upon adjusting wheels 12, thereby raising 01 depressing the forward portion of the platform in accordance with the de sired angle of the undercut.
The forward edge of platform 2 provides a guid'eway for the endless undercutting chain 15, the chain passing around suitable idlers 16 at the front and side of the platform and rearwardly therefrom around the chain-driving wheel 17, the latter being geared to an electric motor 18 supported by the frame part 11. This motor is also geared at 19 to the axle 12 of floor wheels 12, whereby the machine is advanced as the Wheels 12 are suitably ribbed or roughenedto obtain the necessary traction, the forward portion of the machine sliding on the under face of platform 2 and on shoe 7, as will be understood.
The portion of platform 2 which defines the path of the chain cutter may be of any preferred shape or outline. As here shown, it is substantially V-shaped with its apex or angle at the longitudinal center of the machine, whereby a cut of correspondmg form 7 open as shown for i The rear ends of bars is had, the tendency of which is to hold the machine in a straight-ahead course. The chain cutter 15 is of the type usually employed for undercutting, and for which n novelty is claimed.
The top plate 3 of platform 2 is slotted at 20, the slots being; disposed in the direction of movement of: the frame and adapted to project through each slot is a toothed bar 21, the tree forward end 01" which slides on bottom plate t between the spacing}; bars 21 are secured to cranks 22 of a shaft 23, the latter journaled in the several spacing bars 5 and extending from side to side or" the plattorm between plates 3 and 4:. Crank shat 28 may be connected by the worm gearing 24 with the rearwardly extending she-it 25, the latter being geared at 26 to shaft 27 of electric motor 28 mounted on the rearward portion 11 of the frame.
By this arrangement each bar rear portion traveling in a circular the front end reciprocating back and 1" on plate 4, shaft 23 moving clo k-wise in Fig. 5. As a result the toothed tare or each bar is housed at one time and another time is exposec, the exposed portion of travel being in a direction to raise lumps of coal and carry them rearwardly to depositing point, whereupon bar passes below the top plane of plate 8 and moves forwardly while thus housed. This provides an intermittent feed of the coal rearwardly, the slow speed tending to prevent brealcing up of coal lumps and at the time carrying the remaining portions of the coal rearwardly into the conveyor.
Various means, automatic or otherwise, may be employed for receiving and removin; the coal from platform 2. i the present embodiment, at the rear of p iorm 2 is an upwardly inclined conveyor for receiving the coal from said platform and for delivering it to cars or wagons positioned the rear of the machine. As here embodied, the conveyor trough, way or channel is oi: trangular form with one leg thereof paralleling; the rear side ct platform 2 and with the other less 31 and 32 int-lined upward y from the ends of leg 30 and conver the highest point 33 where the trruo'h is into elesaid k the coal a pit car 34: positioned be ath the vated rear end of the conveyor frame, elevated portion being supported by rights 35 rising from trame part 11.
The inner side of each leg, o 'f the conveyor trough is formed of a channeled bar and with the conveyor flights 8S fit the rough as clearly shown i- 5, each flight preferably having an entension 88 which travels over the top edge of bar 36 thereby broadening the transverse the drawings the floor or oottom or" each leg consists of a plate of requisite form. By this means a substantially triangular open-top trough or way is provided, each angle of which is a wheel 40 for directing t e conveyer chain 37, the wheel the uppermost rear angle being geared to motor shaft 27 shown in Fig. 6 whereby the conveyor is propelled by motor 28. By this means both the endless conveyor and the platform eon veyer bars 21 may be actuated by the same motor.
ln operation, the machine is positioned for making the undercut and after the an oi the latter has been determined by adjusting the floor wheels 12 tie chain cutt r is set in motion, and y the same motor means the machine is moved forward through the medium of: fl or wheels 12. As cutting; proceeds, pla ,rm 2 is advanced beneath th breast 01 coal B along with the cutter chain and after an undercut oi sufiicient depth has been attained, he overhangi119, coal B may be dropped by blasting, or other suitable means onto platform 2. It will understood that the mechanism is in operation during the advancing movement of the machine so that while some oi the coal may be dropped within leg 30 of the conveyor, coal dropped forwardly on platform 2 will be worked toward and within reach of the latter by the reciprocating bars 21, thus keeping the platform clear and the conveyor loaded. From leg 30 the loaded conveyor moves the coal upwardly over leg 31 and to a point of discharge 3? where it drops oil' into pit car 34:, the empty portion of the conveyor returning for reloading through le 32.
Various means may be employed for loosening and dropping the undercut coal onto platform 2, the platform serving as a support for the operator or for the mechanism utilized for loosening the coal. As the operation advances, the trackage for the i it cars will be laid so that the latter be positioned beneath the conveyor discharge, whereby by practically a continuous operation the coal is undercut, dropped, car r ed backward and loaded into the pit cars. Instead of relying; on conveyor bars 21 for the coal to within reach of the endless conveyor, after a suitable quantity has l u dropped on the platform, the uncropped portion immediately above the undercut may serve to push tl e loosened coal to rd the conveyor as the platform of the machine advances in the undercut channel.
The general arrangement is such thatthe machine may have a width equal 'to the width of the room, such width depending to a considerable extent on the strength of the roof, etc, andmay range from eight to sixteen feet. The ability to use a machine of this width is brought about by the fact that the coal is not dropped directly upon the conveyer but upon a platform in advance of the conveyer, which platform has a front to rear length sufficient to receive the coal which is dropped, either by use of light blasts or by wedging, and from which platform the coal is moved rearwardly onto the conveyer at a relatively slow speed which will not tend to break up the lumps. Consequently, the conveyer may have its receiving flight equal to the width of the machine and extend transversely of the machine, thus enabling the coal which is fed to the flight to be carried away with sufficient rapidity as to prevent choking of the conveyer system.
This front to rear length of the platform is generally suflicient to permit the cutter chain to out past the first complete cleavage or face without bringing the transverse conveyer flight in the path of the falling coal, the result being that the coal above the undercut can be brought down by the use of light charges or by a wedging, operations which tend to preserve the lump character of the coal and produce a product of greater value. The toothed bars may then be brought into operation to slowly feed the coal toward the conveyer flight, this operation serving the additional purpose of tending to maintain the machine in its forward position so that the cutting operation may proceed concurrently with this feed movement, the bars thus aiding wheels 12 in advanc'ing the machine. This action is also facilitated by the fact that the advance movement of the machine while the material is on the platform will, through the tendency of the standing face of coal B to push the dropped material rearward as the ma chine advances, aids the bars in feeding the coal to the transverse flight of the conveyer.
The operation is substantially continuous, the slow advance of the machine being compensated for by the large quantity of coal which is being worked upon, this slow advance affording the operators sufficient time to provide the drill holes or produce the wedging action. Since the machine is of a type which will permit of taking advantage of the natural cleavage in the coal seams, the blasting charges may be light, since there is no necessity for driving the coal rearward into the mining chamber, it being necessary only to sufficiently release the coal and drop it upon the receiving platform.
It will be understood that the structural features of the machine may be variously embodied without departing from the spirit or scopeof the invention, reference to many such details having been omitted herein as they do not vitally concern the principles underlying the construction and operation of the machine- I I claim: I 1.;In a mining machine adapted for use for coal blasting operations,the combination of a portable frame embodying a vertically shallow platform -forming forward portion, undercutting means mounted on and adapted to be advanced by the platform portion into an undercut, the platform adapted to receive coal dropped thereon, a plurality of conveyer bars adapted to reciprocate in said platform and through the upper face thereof and toward and from the rear thereof for moving coal rearwardly on the platform, a shaft journaled in said platform and provided with a plurality of cranks to which the several conveyer bars are operatively connected, shaft rotating means, and means for deliveringcoal rearwardly from the platform.
2. In a mining machine adapted for use for coal blasting operations, a horizontal vertically shallow coal receiving platform, undercutting means mounted below the upper face of said platform and adapted upon the forward movement of said platform to form an undercut, an endless conveyer movable across and arranged to convey coal from said platform and to carry the same to a point above and in the rear of said platform, and reciprocating means protruding through said platform for moving coal from said undercutting means to said endless conveyer.
3. In a mining machine adapted for use for coal blasting operations, endless undercutting means, a coal supporting frame of Vertically shallow depth arranged in the rear of said undercutting means and constructed to project into the undercut and to receive the coal blasted from above the undercut, reciprocating means, mounted substantially throughout the width of said frame, for moving coal thereon to the rear thereof, and an endless conveyer for carrying the coal from said coal moving means to a point above and to the rear of the machine.
4. In a mining machine adapted for use for coal blasting, a coal receiving platform of such height as to be capable of projecting into an undercut, endless undercutting means movable around the forward edge of said platform, an endless conveyer in the rear of said platform, and reciprocating coal moving means between said undercut ting means and said endless cover.
5. In a coal mining machine, a frame adapted to enter a horizontal undercut and provided with a central, forward apex, rearwardly inclined edges extending from said apex and rearwardly extending sides at the nism adjacent said zone but not intruding ends of said inclined edges, undercutting thereon. 10 mechanism mounted on said frame and In testimony whereof I afiix my signaadapted to operate along the above menture in presence of two witnesses.
tioned apex, edges and sides, said frame THOMAS DONOHOE. having a platform bounded by said apex, Witnesses: edges and" sides and provided with a coal- J. M. NESBIT,
receiving zone and coal removing mecha- ALEX. S. MABON.
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US1387886A true US1387886A (en) | 1921-08-16 |
Family
ID=3399581
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US1387886D Expired - Lifetime US1387886A (en) | Coal-mining machine |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US1387886A (en) |
-
0
- US US1387886D patent/US1387886A/en not_active Expired - Lifetime
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US2694562A (en) | Apparatus for continuously digging coal | |
| US1726963A (en) | Mining and loading machine | |
| US1603621A (en) | Coal mining and loading machine | |
| US2105504A (en) | Method of mining coal | |
| US1549699A (en) | Mining and loading machine | |
| US1645007A (en) | Mining machine | |
| US1821438A (en) | Apparatus for handling coal | |
| US2368863A (en) | Mining machine | |
| US1387886A (en) | Coal-mining machine | |
| US1700294A (en) | Loading machine | |
| US1517095A (en) | Mining apparatus | |
| US2689717A (en) | Plow mining method and apparatus | |
| US1079353A (en) | Mining-machine. | |
| US2077432A (en) | Apparatus for mining coal | |
| US1638507A (en) | Mining and loading machine | |
| US1283880A (en) | Mining-machine. | |
| US1617941A (en) | Mining apparatus | |
| US1290021A (en) | Mining and loading machine. | |
| US1190300A (en) | Mining-machine. | |
| US1776799A (en) | Apparatus for mining | |
| US2235099A (en) | Apparatus for mining coal or the like | |
| US1754276A (en) | Loading machine | |
| US3317245A (en) | Propelling and steering system for mining machines | |
| US1290020A (en) | Mining and loading machine. | |
| US1737327A (en) | Mining machine |