US831516A

US831516A - Mining-machine.

Info

Publication number: US831516A
Application number: US24564205A
Authority: US
Inventors: Charles Mead
Original assignee: LEWIS PRAGER; LOUIS A SCHLESINGER; MINNIE WOLF; PRAGER Co Ltd M; W W WOODS
Current assignee: LEWIS PRAGER; M PRAGER COMPANY Ltd; W W WOODS; LOUIS A SCHLESINGER; MINNIE WOLF; PRAGER Co Ltd M
Priority date: 1905-02-15
Filing date: 1905-02-15
Publication date: 1906-09-18
Anticipated expiration: 1923-09-18

Description

WITNESSES:

c. MEAD. MINING MACHINE.

APPLICATION FILED $313.15. 1905.

PATENTED SEPT. 18,1906.

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r INVENTOR (harlasMead,

ATTORNEYS No. 831,516. 1 PATENTED SEPT. l8, 1906. U. MEAD.

MINING MACHINE.

APPLIGATION FILED PBB.15. 1905.

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PATENTED SEPT. 18, 1906- C. MEAD. MINING MACHINE. APPLICATION FILED IEB.15,1905.

3 SHEETS-SHEET '3.

0., WASHINGTON, p. c.

UNITED srA rns PATENT OFFICE.

CHARLES MEAD. OF MURRAY, IDAHO, ASSIGNOR OF ONE-HALF TO THE M. PRAGER COMPANY, LIMITED, OF MURRAY, IDAHO, A CORPORA- TION OF IDAHO, ONE-SIXTEENTH TO LOUIS A. SOHLESINGER, ONE- SIXTEENTH TO LEWIS PRAGER, AND ONE-SIXTEENTH TO MINNIE WOLF, OF MURRAY, AND OND-SIXTEENTH TOW. W. WOODS, OF

WA LLAOE, IDAHO.

MINING-MACHINE.

Specification of Letters Patent.

Patented Sept. 18, 1906.

To all whom, it may concern.-

Be it known that I, CHARLES MEAD, a citizen of the United States, residing at Murray, in the county of Shoshone and State of Idaho,

have invented certain new and useful Improvements in Mining-Machines, of which the following is a specification.

My invention relates to mining-machines of that class intended to be operated by [0 manual labor for the purpose of drilling a hole in rock or in soil.

Some of the parts of my present invention are designed as improvements on the rockdrill disclosed in a prior United States patent, No. 736,758, granted on August 18, 1903.

Briefly stated, some of the leading features of the present invention, which are improvements upon the drill disclosed by the aforesaid patent, are, first, the employment of a movable rigid drill-supporting arm adapted to be held in a normal operating position by a suitable retractor, said arm being used in lieu of the heavy, cumbrous, and costly steelplate main spring of the patented drill; sec 0nd, a novel construction of the clutch which engages automatically with the drill for the purpose of returning it to the bottom of the drill-hole after the drill shall have been lifted with the arm, said clutch being releasable at 0 will from engagement with the drill and also permitting the free downward movement of said drill under the blow of the hammer; third, a novel means for giving a partial turning movement to the drill-turning cylinder,

5 said means being in part actuated by the movement of the striking-arm and also operating independently thereof, so as to secure a positive turning movement of the cylinder and overcome any tendency of the working 0 parts to bind or stick in the operation of the machine. These several improvements,

as well as those to be hereinafter described,

tend to materially simplify the construction of the machine, reduce its weight, and in- 4 5 crease its efficiency.

Another improvement which I have made consists in the provision of means for mounting the machine on a post or standard when it is desired to use the machine in tunnelwork or the like. The supporting devices permit the machine to be rotated in a vertical of practical service.

easily adjusted, and operate efficiently in fasplane or in a horizontal plane, so as to enable it to assume either of a number of positions which may be demanded by the conditions Said devices are simple,

tening the machine in working condition, while permitting it to be dismounted and changed, as desired.

Reference is to be had to the accompanying drawings, forming a part of this specification, wherein like characters of reference are used to indicate corresponding parts in all the figures.

Figure 1 is a perspective view illustrating my machine mounted in one position on a post or column, so as to enable it to be used in tunnels. Fig. 2 is a view in side elevation, on an enlarged scale, of the machine proper dismounted from the supporting devices. Fig. 3 is a view in perspective of a portion of the frame and some of the working parts. Fig. 4 is a plan view, partly broken away, of a portion of the drill-turning mechanism, said view also showing some of the devices by which the drill is drawn back to the bottom of the drill-hole following the rebound from a hammer-blow. Fig. 5 is a cross-section on the line 5 5 of Fig. 6. Fig. 6 is a vertical section on the line 6 6 of Fig. 4. Fig. 7 is a detail view, in side elevation, partly broken away and in section, of a portion of a supporting-column and an adjustable carryingarm on said column. Fig. 8 is a sectional plan view through the supporting-column, the plane of the section being indicated by the dotted line 8 8 of Fig. 7. Fig. 9 is an enlarged view, in side elevation, of the clamps which are employed for holding the machineframe on the supporting-arm; and Fig. 10 is %n end elevation of the devices shown by The frame which carries the working parts of the machine may be constructed as disclosed by my prior patent, or it may be of any suitable or preferred construction; but, as shown more clearly by Figs. 1, 2, and 3, the frame A consists of the side members a, a head or fork a, and a cross-head M, the latter being shown more clearly by Figs. 5 and 6. The members a are united at one end by the fork a, which is shown as provided with a cross-head a drill, (indicated at E.)

socket a into which may be screwed a terminal screw or foot-piece of a supporting-colvumn, as will be hereinafter described. The cross-head a is provided withopenings (1 through which are adapted to pass the side members a of the frame, said cross-head being secured to the frame by any suitable or preferred means.

Secured rigidly tothe side members a of the frame A are short posts 5, and through the free ends of these ,posts are passed the threaded rear ends of tie-rods 6, the front ends of said rods being fitted in openings 7 of the cross-head a or in suitable lugs provided on said cross-head. Check-nuts 8 are screwed on the threaded front and rear ends of the rods for the purpose of binding the rods firmly to the posts 5 and the cross-head a said tie-rods serving to materially strengthen the frame in a longitudinal direction.

It is evident that one pair of nuts may be screwed on the tie-rods to have engagement with the respective sldes of a post 5, while the other- 'pair of nuts are adjustable into engagement with the respective edges of the crosshead, thus making provision for taking up slack and holding the parts of the frame in a solid rigid condition. The posts 5 have bearings for a short horizontal shaft or arbor 9, which extends transversely across the frame, said shaft being arranged above the members a and supported between the fork a and the This shaft or .arbor supports an elbow-shaped drivinglever B and a feed- .lever C, said levers being fitted loosely on the shaft alongside of each other and the feedlever being in the ath of a projection on the driving-lever, so t at the feed-lever will be operated in one direction by the movement of said driving-lever. The driving-lever is fulcrumed at its knee or angle by mounting said lever on the shaft or arbor 9, said driv 'ing-lever consisting of a long arm I) and a short arm I). Said-driving-lever is held normally in a working position by a suitable form of retractor, herein shown as a coiled spring 10, one end of which is connected with the short arm I) of the lever, while its oppo site end is anchored on a hook 1 1, attached to a part of the machine-frame, preferably the fork (1 thereof.

D designates a rigid striking-arm, which is preferably made of forged or wrought metal,

said arm consisting of the parallel members (1, united by a cross-piece d, all made'in one piece.

' movement bodily with the striking-lever un- The striking-arm is bent or offset lat-. erally, as at 61 and the cross-piece is proder the blow of the hammer, and this strikingelever forms a shiftable connection between the striking-arm and the frame, so that the arm will be movable practically in a rectilinear path with the drill E when the parts are driven in one direction under the blow of a hammer delivered upon a head of the drill and upon the striking-head D of the strikingarm.

The lower part of the striking-arm straddles the free end of the arm I), forming a part of the elbow driving-lever, and these parts are connected pivotally by a bolt or pin 12, which passes through the members 01 of the striking-arm and the lever-arm b. The striking-arm may be connected at different points to the elbow-lever by adjusting the bolt or pin 12 in one or the other of a series of apertures 13, which are provided in the leverarm I).

The drill-turning mechanism has a drillguide F, which is made in the form of a cylinan aXial opening f of a size and shape to receive the drill E and cause it to turn .with the guide; but this opening permits the said drill to have sliding movement freely in the guide. Loosely mounted on a fianged upper part of the drill-guide is the turning-ring 15, which is adapted to rotate freely in .one direction on said guide; but it is constructed to turn the guide when moved in an opposite direction.

This ring is shown by Fig. 4 as provided with an internal ratchet or gear 16, and with one of the teeth of this ring is adapted to engage a pawl 17, the latter being mounted on the upper part of the guide or cylinder F, so as to move therewith. Said awl is held in engagement with the turning-ring by a spring 18, and when the ring turns in the direction indicated by the arrow in Fig. 4 the pawl is operated by the ring so as to turn the cylinder, although the movement of the ring in an opposite direction permits the guide or oylinder to remain at rest and to slip over the teeth 16. The turning-ring is furthermore provided with plates or brackets 19, between which is fitted one end of a feed-rod 20, the latter being pivoted, as at 21, to the turning ring. This feed-rod extends backwardly to the upper part of the feed-lever C, and said rod has a pivotal connection by a pin'22, with said feed-lever.

The feed-lever is moved positively in one direction by disposing it in the path of projection 23 on the short arm I) of the drivinglever B, (see Fig. 3;) but said lever O is held normallyin aworking position by a retractor, herein shown as a coiled spring 24. This spring 24 and the lever C are independent of the spring 10 and the driving-lever B, so

that the feed mechanism for the drill-guide end of said spring is connected with a pivoted hook 25, that is attached to the feed-lever C. A buffer or cushion 26 is attached to the feed-lever C and arranged in the path of the projection 23 on the drivinglever. This buffer is represented by Figs. 1 and 3 as a hand or sleeve of rubber or other suitable material; but I wish it to be understood that I do not strictly confine myself to this sleeve, because other forms of buffers may be employed between the two levers B C for the purpose of taking up the shock or jar due to the engagement of the projection 23 of the driving-lever with the feed-lever C. The buffer or cushion serves a twofold purpose in my machinefirst, a means for absorbing the shock or jar, and to permit the parts B G to have a relative movement equivalent to the depth of the cut made in the bottom of the drill hole by the bit of the drill E at each driving movement thereof.

In the drill disclosed by my prior patent I employ a form of clutch which is adapted to be clamped tightly around the shank of the drill for the purpose of opposing the rebound of the drill and for returning the drill to the bottom of the drill-hole. Said patented clutch was designed to be secured tightly against the drill, requir ng time, and was not altogether satisfactory in service. I now employ a new form of clutch mechanism adapted to act automatically on the drill E and which permits the free driving movement of the drill under the blow of the ham mer. This mechanism contemplates the employment of a clutch-lever G, which is rovided with a ring or eye g, through which the drill E is adapted to slide freely when driven by the hammer. The lever G is adapted to rest in the forked end 27 of a fulcrum plate or bracket 28, the latter being secured to the upper end of the drill guide or cylinderF. (See Figs. 2 and 6.) The clutchlever is drawn normally to an angular or inclined position relative to the drill E by a suitable form of retractor in order to make the eye g impinge said drill, and in the drawings this retractor is shown in the form of a loop or yoke 29, having its legs-or rods 30.

sliding freely in the drill guide F. Said guide is shown as-having openings 31 32 at the respective ends of the guide, the openings 32 being of a larger diameter than the openings 31. The legs 30 of the yoke pass loosely through said openings of the guide F, so as to lie on opposite sides of the opening f for the drill. On the legs or rods 30 are litted loose washers 33 and the springs 34, said washers 33 being pressed by the springs against the lower ends of the openings 31 in the drill-guide. The ends of the rods or legs 30 are threaded for the reception of confining and adjusting nuts 35, which afford seats for the springs 34 and are adjustable on the rods so as toregulate the tension of the springs. The openings 32 provide for, the free escape of dirt from the drill-guide F, and these openings also accommodate the lower parts of the springs. 34, so that the nuts 35 may be adjusted for regulating the strength of said springs. It will be seen that the springs act on the legs or rods to draw the yoke 29 downwardly against the clutch-lever for the purpose of holding it in an inclined position, so that the eye g will bind on the drill. The binding action of helever on the drill opposes the rebound of the drill following the blow of the hammer, and the more pressure or force GX- erted by the drill during this rebound causes the clutch-lever to bind more tightly against said drill. This clutch, however, offers no resistance to the movement of the drill under the force of the hammer in the performance of its work in penetrating the rock or soil, and the clutch is capable of adjustment easily in order to release the drill by simply pressing on the outer edge of the clutch-eye g with one hand, the drill being easily lifted out of the machine with the other hand. The strength of the springs 34 is so adjusted as to allow the rebound of the drill a sufficient distance for the drill-bit to clear the cut made by said bit on the driving movement of the drill, after which the drill guide or cylinder F is turned by the feed mechanism and the springs 34 react, so as to draw the drill back to the bottom of the drill-hole, the drill being in position toreceive the blow. All these movements are made very rapidly, so as to enable three men striking in rotation on the drill-head and the striking-head.-

By reference to Fig. 6 it will be seen that the middle portion of the drill guide or cylinder F is cut away to allow any dirt which. may enter the holes 31 32 to fall out through the opening f, provided for the accommodation of the drill.

The strikingrarm D is guided in its reciprocating movement with the drill E by the employment of guide devices located on the side members a of the machine-frame and in front of the driving-lever B. These guide devices consist of short posts 36, secured rigidly to the frame member a, and a roller 37.

clamp being a plate i.

The posts 36 are-fastened individually to the members a, and they are joined by a tie bolt or rod 38. The roller 37 is mounted for operation freely on the posts 36, and said roller is in the path of the striking-arm D, so as to minimize the friction between the guide and the arm as the latter moves bodily under the blow of the hammer.

The striking-head D of either iron or steel which is turned into the form of a ring, the diameter of said annular cap being sufiiciently large for the drill to pass through and to turn freely. As is usual, the drill E is provided with a head which cannot pass through the striking-head, and the top inner edge of said striking-head is intended to be chamfered or beveled to allow the drill-head to lie flush with the top of the striking-head. In placing the drill in position it is passed through the annular strikinghead, the upper end of the striking-arm, the eye of the clutch-lever, and the passage f of the drill uide or cylinder, the opposite end portion of the drill passing to the rock. The drill is so positioned that when the drill-bit touches the rock the striking-head D presses against the under side of the drillhead, and when thus assembled the machine is ready for work, so that the operators can commence hammering on the drill-head. After each blow the drill is raised from the bottom of the drill-hole far enough to allow the feed mechanism to rotate the drill-guide for the purpose of turning the drill upon its axis, and after the turn is completed the springs 34 operate the clutch mechanism to draw the drill back into the hole for a distance sufficient to make the drill-bit rest on the rock, the parts being in position to receive the hammer blow. This operation takes place automatically until the drill becomes dull or has run down the required distance. At this stage of the operation the drill should be removed by releasing the clutch and withdrawing the drill endwise from the machine, whereupon a longer drill is inserted in the described manner and the operation may be renewed.

In cleaning out the drill-hole the strikingarm D should be laid back over the levers B C, the drill being removed, thus permitting a scraper to be inserted through the opening f through the drill-guide and thrust downwardly into the drillhole.

As one means for supporting the drill in working position within a tunnel I have shown. a post or column H in Figs. 1, 7, and 8 of the drawings. This post is provided with a crown h, and in the lower end of'said post is secured a spindle h, having a foot 7L Extending from this post is a carrying-arm I, which is rigidly joined to one part c of a two-part clamp, the other member of said The parts of the clamp are adapted to be drawn into tight [horizontal plane around said column. is made of one piece.

frictional engagement with the column by bolts '27. It will be seen that the arm I is clamped securely on the column for the purpose of maintaining the machine in a working position but theclamp may be released, so as to raise or lower the arm I on the-column or to permit the arm to be turned in a The arm I is provided with a member J, which lies at an angle to the arm, and this member is secured detachably to the arm, so that it may be removed and replaced at will. As one means for attaching the member to the arm I provide said arm with a threaded tenon j and the member with an opening j. The perforated end of the member may be slipped over the tenon j and the parts secured in position by a nut 3' although this nut may be removed from the arm and the member J detached from the arm I.

The machine-frame is adapted to be mounted on the arm I or the member J thereof, and for this purpose I employ a clamp adapted to grip the part I or J on which the machine-frame is to be supported. This clamp consists of a bridge-plate K, a clamp-plate L, .and an eyebolt M; (See Figs. 9 and 10.) The bridge-plate K is provided with eyes 7c, adapted to fit on the side members a of the frame, said bridge-plate being shown by Fig. 1 as spanning theframe between the guide-posts 36 and the crosshead (L The bridge-plate K and the clamping-plate L are provided with alined holes through which is adapted to pass the shank or stem of the eyebolt M, and on one end of this bolt is screwed a clamping-nut m, which is adapted to bind against the bridge-plate K. The plate L is provided with grippers 0, each of which is made of spring-steel and is riveted or otherwise fastened to the plate. Each gripper is bent or doubled upon itself to provide the divided ring or eye 0, which is approximately circular in form, but which is not continuous. The grippers have curved arms 0, which extend backwardly and outwardly from the divided eye, so as to furnish the means for attachment to the clampingplate. The eyes 0 of the grippers do not extend in the same direction asthe loops is of the bridge-plate; but said divided grippereyes areiarranged for their axes to lie at substantially right angles to the axes of the eyes it. Any desired number of these grippers 0 may be used but, as shown by Fig. 9, I em- ICC ploy two grippers disposed on opposite sides of the eye m of the bolt M.

If it is desired to mount the machine on the arm I, the member J is detached and the grippers O and the'eyebolt M- are adjusted over the arm I for the purpose of connecting the machine-frame to said arm. The nut m of the eyebolt is tightened, so as to draw-the eye m of said bolt against the arm I, and this operation draws the plate K against the to the arm.

plate L for the purpose of exerting pressure on the spring-grippers 0, thereby making said grippers tightly engage with the arm I, the eyebolt M cooperating with the parts K, L, and O of the clamp in a Way to rigidly and firmly secure the machine-frame It is evident that the bolt M may be released, so that the machine may be swung through the whole or any art of a circle around the arm I or its mem er J, accordingly as the machine is mounted on either of said parts. Furthermore, the machine may be swung with the arm I for a considerable distance and from right to left, and the arm may be raised or lowered on the column or swung around the column, so as to place the machine in a required position for drilling a hole. The advantage of the member J is that the machine when mounted thereon may be set up close to the face of a tunnel; but when this member is not required it can be disconnected from the arm by removing the nut j For close work in slopes and for shaftwork the threaded stem h of the column may be disconnected and screwed in the socket a of the fork a In Fig. 1 of the drawings, I have shown the drilling mechanism mounted on the angular member of the supporting-arm, which is clamped on the column, said drilling mechanism being in a position to drill what miners term a half-doWn-face hole, but it is evident that the drillin mechanism may be mounted on the arm I and that the drilling mechanism may be adjusted in either a horizontal direction or in a vertical direction, so as to assume any required position for operation. The drill having been inserted through the striking-head, the striking-arm, the clutch, and the revoluble drill-guide, and the parts being in proper position for oper ation, one or more miners are stationed at the machine with sledges for the purpose of driving the drill into the rock or the material. When a blow is delivered upon the head of the drill, the latter is forced endwise and de presses the arm D, which owing to its shiftable and pivotal connection with the frame through the driving-lever B is adapted to move in a substantially rectilinear path with the drill for the distance required for the drill to penetrate the rock. The same blow that drives the drill into the rock works the various parts that lift the drill, insuring its turning, and replaces the drill at the bottom of the drill-hole ready for the next blow, and these operations are performed so quickly that three miners may be employed to operate the machine by striking on the drill-head one after the other. The downward movement of the drill E through the clutch-eye g of the lever G meets with practically no resistance from the means that operate to check the rebound of the drill and to return said drill to the bottom of the drill-hole. In

the operation of the clutch the parts are so adjusted as to insure lifting of the drill sufficient for its bit to clear the cut in the rock made by the blow, after which the feed mechanism operates to turn the drill-guide F and the drill the required distance, and thereupon the springs 34 contract and draw the drill back to the bottom of the hole. The clutchsprings are adjusted, as heretofore described, so that the tension of the springs may be stiffened or decreased, as desired. The washers 33 on the clutch-rods ermit the free play of said rods in the dri l-guide, so that on the upward movement of the clutchrods they draw only on the nuts 35, which of course compresses the springs against the loose washers. When the clutch-rods cease to be drawn upward, the springs react and draw the clutch-rods and the clutch in an opposite direction, thus making the lever bind on against the drill and draw it back into the bottom of the drill-hole.

In my prior machine the means for turning the drill-guide was operated by a single lever that is actuated on the movement of the striking-head, and it is found that the mechanism was liable to bind or stick when the drill is operating in soft rock, in which case there was no chance for the lifting of the drill to cause the axial turning movement of the drill-guide.

In my resent construction the means for turning t e drill-guide operates in a measure independently of the striking-arm. It will be seen that when the striking-arm is deressed the lever B is moved, so as to expand the spring 10, and when the blow has expended its force the spring returns the lever B with force against the under side of the drill-head, and thereby lifts the drill from the bottom of the drill-hole. Now when the arm D is depressed the projection 23 of the lever B is thrust forward, so as to engage with the feed-lever C and press it forward, so as to actuate the rod 20, which on its return movement operates the feed mechanism so as to partially turn the drill-guide F, the forward movement of the lever O expanding the spring 24. The reaction begins by the contraction first of the spring 10, which returns the lever B and the striking-arm D to their raised positions, so as to lift the drill, and immediately the spring 24 acts on the lever C, so as to draw back the lever and the rod 20. Thus the action of each lever is independent of the other, which renders it impossible for either lever to bind, and thereby the operation of the feed mechanism is made positive and certain.

It will be seen that the projection 23 of the driving-lever operates on the cushion 26 in impelling the feed-lever in a forward direction. This not only takes up the shock or jar incident to the operation of the levers one on the other, but the driving-lever is permitted to move in a forward direction for a distance equivalent to the compression of the cushion, this limited movement being about equal to the distance that the drill penetrates in rock at each blow. Thus the actual resistance the hammer is compelled to overcome before its force is expended on the drillhead is the resistance offered by the spring 10 of the driving-lever.

It will be seen that the striking-arm D may be connected at a number of points to the driving-lever and that the feed-lever C may likewise be connected at a number of points to the feed-rod 20, thus making provision for giving more or less turn to the drill-guide at each blow of the hammer.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a machine of the class described,a frame, a lever fulcrumed thereon, a rigid striking-arm pivoted to said lever and supported thereby, a drill fitted to the strikingarm for movement with the same, and means operating through the lever for holding the striking-arm and the drill in working positions.

2. In a machine of the class described, a frame, an elbow-lever fulcrumed on the frame, means acting on one arm of the lever forholding the same in working position, a rigid striking-arm pivoted to the other arm of said lever and supported by the latter, and a drill connected tosaid striking-arm for movement therewith.

3. In a machine of the class described, a rigid striking-arm offset at one end and provided with a striking-head, a drill fitted loosely in the striking-head and exposed through the same, a frame, a lever fulcrumed on the frame and supporting the strikingarm, and means cooperating with the lever for holding the striking-arm and the drill in working positions.

4. In a machine of the class described, an elbow-lever, a rigid striking-arm pivotally supported by the lever, and a rctractor connected with said arm.

5. In a machine of the class described, a

lever, a striking-arm pivoted thereto, a drillturning mechanism, and means actuated in one direction by said lever and arranged to operate independently of the lever for the operation of the drill-turning mechanism.

6. In a machine of the class described, a lever, a striking-arm supported thereby, a drill-turning mechanism, a lever connected with said drill-turning mechanism and operated by said first-mentioned lever, and a retractor for the second-named lever.

7. In a machine of the class described, a striking-lever, a striking-arm adapted to operate said lever, a drill-turning mechanism, an independent feed-lever operated by the striking-lever and adapted to actuate the drill-turning mechanism, and separate retractors for the levers.

8. In a machine of the class described, independent spring-actuated levers mounted for movement on the same axis and arranged for one lever to be actuated by the other, blow-operated means for operating one of said levers, and a drill-turning mechanism actuated by the other of said levers.

9. In a machine of the class described, an elbow striking-lever, a striking-head connected with one arm thereof, drill-turning mechanism, a feed-lever in the path of the other arm of the striking-lever, and means connecting the feed-lever with the drill-turning mechanism.

10. In a machine of the class described, a frame, a lever, a strikingarm, a plurality of pivotal connections between the frame and said arm, a guide for the striking-arm, and means for holding the parts in operative positions.

11. In a machine of the class described, a frame, a striking-arm supported in said frame by a plurality of pivotal jointed connections therewith, and a guide for said arm.

12. In a machine of the class described, a frame, a striking-arm, a freely-shiftable and pivotal connection between the arm and the frame, and means for holding the arm in a normal operative position.

13. In a machine of the class described, a frame, drill-turning mechanism, a striking arm having a shiftable pivotal connection with the frame, means for actuating the drillturning mechanism by the movement of the arm, and springs for operating the arm and the said actuating means independently.

14. In a machine of the class described, a striking-arm, a drill connected with said arm and adapted. to be moved in one direction thereby, and means operating independently of said arm for returning the drill to the bottom of the drill-hole, said means comprising a clutch adapted to impinge the drill, and means for moving the clutch and the drill in an opposite direction to that in which the drill is moved by the striking-arm.

15. In a machine of the class described, a striking-arm, a drill connected with said arm and adapted to be moved in one direction thereby, a clutch adapted to permit free driving movement of the drill and operating to impinge said drill as it rebounds from the drill-hole, and means independent of the striking-arm for moving the clutch and the drill in the other direction, whereby the drill is restored automatically to the bottom of the drill-hole.

16. In a machine of the class described, a striking-arm, a drill connected with said arm and adapted to be moved in one direction thereby, a clutch-lever having an eye, which permits free driving of the drill in one direction, and which is adapted to impinge said drill on its rebound from the drill-hole, and means independent of said striking-arm and operating through the clutch-lever for restoring said drill to the bottom of the drillhole.

17. In a machine of the class described, a rotatable drillguide, a striking-arm, a drill fitted to said arm and the guide, a single clutch-lever fulcrumed. on the drill-guide, said clutch-lever being independent of the strik ing-arm and adapted to have gripping engagement with said drill on its rebound from the drill-hole, and means acting through the lever for returning the drill to the bottom of the drill-hole.

18. In a machine of the class described, a rotatable drill-guide, a striking-arm, a drill connected with said arm for endwise movement therewith, and also rotatable with the drill-guide, a clutch-leversupported by said guide and adapted for engagement with the drill, and a spring-actuated yoke engaging with said clutch-lever for returning the drill to working position in the drill-hole.

19. In a machine of the class described, a drill-guide, spring-actuated rods connected by a yoke and supported by the guide, and a clutch-lever fulcrumed on the drill-guide and engaging with said yoke.

20. In a machine of the class described, a drill-guide having a drill-opening and parallel passages, the latter being larger in diameter at one end than at the other, spring-controlled rods slidable in said passages, and a clutch-lever supported by said guide and controllable by said rods.

21. In a machine of the class described, a drill-guide, a fulcrum-bracket thereon, a clutch-lever fitted to said bracket and having a drill-eye, and a spring-actuated yoke engaging said lever.

22. In a machine of the class described, a drill-guide, a clutch-lever, a yoke-engaging said lever and having rods or legs slidable in the guide, springs on said legs, and means for regulating the tension of the springs.

23. In a mining-machine, a carrying-arm, a drillframe, a plate on said frame, another plate, grippers on the second plate and adapted for frictional engagement with said arm, and means for drawing said plates toward each other and compressing the grippers on the arm.

24. In a mining-machine, a carryingarm,

a drill-frame, cooperating plates, one of which is on the drill-frame, spring-gr1ppers engaging frictionally with the arm, an means for compressing the grippers on said arm.

25. In a mining-machine, a carrying-arm,

a drill-frame, divided spring-grippers engagand means for compressing arm, whereby the drillremovably and adjusting with the arm, the grippers on the frame is supported ably on the arm.

26. In a machine, a drill-frame, a carryingarm therefor, a plate having a plurality of compressible grippers which are fitted to said arm, another plate engaging with the drillframe, and a bolt fitted to the arm and engaging with both of ing between the grippers of the first-named late.

P 27. In a machine of the class described, a carryingarm, a drill-frame, cooperating plates, one of which is on said frame, frictional grippers on the other plate, and a bolt connecting the two plates and engaging with said arm.

. 28. In a machine of the class described, a carrying-arm, a plate, compressible grippers attached to said plate and engaging said arm, a drill-frame, a clamping member engaging the drill-frame, and a single bolt attached to the arm and adapted to draw the plate and clamping member together, whereby the grippers are compressed on the arm.

29. In a mining-machine, an arm, adrillframe, cooperating plates, one of which is on the drill-frame, divided spring-grippers on the other plate, and means for compressing the grippers on the arm.

30. In a mining-machine, an arm, a drillframe, divided spring-grippers compressible around said arm, and means connecting the grippers with the frame.

31. In a mining-machine, an arm, a drillframe, cooperating plates, one of which is on the drillframe, grippers on the other plate and fitted on the arm, and a bolt connecting the two plates and fitted to the arm.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CHARLES MEAD Witnesses:

L. B. MACK, G. J. BOWERS.

said plates, said bolt be-