US2434120A

US2434120A - Drilling apparatus

Info

Publication number: US2434120A
Application number: US525869A
Authority: US
Inventors: Win W Paget
Original assignee: Joy Manufacturing Co
Current assignee: Joy Manufacturing Co
Priority date: 1944-03-10
Filing date: 1944-03-10
Publication date: 1948-01-06
Anticipated expiration: 1965-01-06

Description

Jan. 6, 1948. w. w. PAGET u I2,434,120

' QRILLING APPARATUS Jan 6, W W PAGET DRILLING APPARATUS Filed March `1o, 1944 5 sheets-sheet 2 wig' W am W m mw, ,7 M r O E Nv MJ j wm. *M 1 uw nu wx@ R W um, Nw? ,QA um, N% m www, Q u @w Q mw o Nm m v wr/)rw/r f. r rr ,NMr/rMH/ A d WM Q mi m Q bm www www mx mm? :Hl mw@ nHr Hlm. 9m l mw Sw Q mw mmm Q QQ .Q um Q. W

Jan. 6, 1948. w, PAGET 2,434,120

DRILLINc. APPARATUS Filed March I, 1944 l 5 Sheets-Sheet 3 Y y U-...

DRILLING APPARATUS Filed March l0, 1944 5 Sheets-Sheet 4 w. w. PAGET 2,434,120A

Jan. 6, 1948.

W. W. PAGET DRILLING APPARATUS Fil'ed March l0, 1944 5 Sheets-Sheet 5 P05/Cf..

15e @en for fifty Patented Jan. 6, 1948 DRILLING APPARATUS Win W. Paget, vMichigan City, Ind., assignor to k.l'oyYManuf-acturing Company, a corporation of Pennsylvania Application March 10, 19421, Serial No. 525,869

(Cl. .Z55-47;)

24 Claims. 1

This invention relates to drilling apparatus, and more particularly vto improvements in feed control means for drilling apparatus ofthe rotary type.

In drilling hard material, such as rock,'fb.y rotating a bit impregnated with diamonds or borts while it is in engagement with lthe material to be drilled, and feeding the bit vtoward the work as the material is cut away, there may be, if the bit is fed too rapidly, la binding of Vthe bit, resulting in an overloading of the bit Irotating motor, a burning of the bit vor a fracture of some part of the drilling apparatus. Some `of these diliculties may be encountered, vregardless of the type of bit, if excessive feeding pressures are used. By controlling automatically the rate of feed Ain accordance with the resistance to -rotation of the drill bit, it is possible to Vprevent the undesirable results above mentioned from toccurring, and at the same time to maintain the feeding pressure that is necessary to obtain the fastest drilling speed.

The invention from one aspect may comprise a drill feeding means embodying relatively rotatable, mechanically interengaged feeding elements for effecting feed of a drilling implement, to-r gether with means for automatically controlling the relative rotation of the feeding Yelements .in accordance with the resistance -to rotation `of vthe drilling implement, to regulate the yrate of feed. Desirably, the invention may comprise a vdrill feeding means including a torque motor yfor -providing a feed-effecting force, and means automatically controlled vby load changes on the drilling implement to control the transmissionof the force provided by the torque motor to effect a feeding of the drilling implement. Thefeeding means may comprise relatively rotatable feed screw and nut elements and a friction device, controlled by the load changes on the drilling implement, for automatically controlling the relative rotation of the feeding elements. The friction device may desirably be in the form of a brake and may control rotation of either the Yfeed screw or the feed nut. In a preferred embodiment the brake may Lbe applied to resist rotation of the element rdriven by the torque motor, thereby reducing the relative rotation between the feed elements and decreasing the rate of feed. Again, the brake may be normally applied Ato hold one of the feed elements against rotation While the other element is rotated by the torque motor, and, on overloading of .the drilling implement, the brake may be automatically releasedso thatfthe normally braked element vmay rotate, therebyreducing the relative rotation between the elements and decreasing the -rate Aof feed. While reaction of the V.motor casing isa preferred source of feed control-ling force, lit `will be understood that 'rela'- tive rotation between parts in the drive of the bit, or variations in the 4power demand .of an electric bit-rotating motor, Vmay be caused :to effect feed control without departing from-my invention in its .broader aspects. In .different embodiments .of the invention, the motor for rotating .the ydrilling implement, as well as .the torque motor, may -be caused either to move along a, guide :member with the drilling :implement xduring feeding .of the latter or may beheld stationary while .the drilling implement is 4*fed relative itc Vits work.

It is .therefore an object of this invention to provide an improved drilling .apparatus having improved feed control means embodied therein. Another object is fto .provide in a rotary .type drilling apparatus yan improved feed control means operative:tocontrolithe `feeding of the drill bit .in accordance with Ythe .resistance to'rotation of the bit. Still another object isV to provide an improved feed `control means .for a rotary type drilling ..apparatus, .said feed ,control means 'op-Y erative in vaccordance with :the load on the bit rotating motor for varyingautomat'icallyJthe'drill feed. Another object .is to provide relatively rotatable feeding elements for .a bit rotating motor, and vfeed control-means operatively connected with the bit rotating motor and actuated thereby as the load on the motor changes for altering the resistance vto rotation zof oneofsaid elements. Still another lObjectis -to .provide improved feejding :means for a drilling implementof the rotary type, said feeding means including relatively rotatableffeedingelements operative on relative rotation to effect feed, and means responsive yto Vthe resistances to rotation of said drilling implement `for controlling `the relative rotation between said feeding elements. Yet .another object sis vto rprovide relatively rotatable feeding elements for adrilling implementof the rotary type, and means Vforcontrolling the relative rotation between said elements, said controlling "means including means for resisting the rotation of one `ofsaid feeding elements whereby the rate. of relative rotation lbetween said lelements is reduced,.and means for actuating the resistingzmeans to resist the rotationof the feeding element when the `resistance to rotation of the .drilling implement exceeds `a .predetermined amount.y Another object is fto ,provide relatively rotatable Vfeeding elementsgfora drilling implement :of y.the-.rotary type, 'withcontrolling means'v vention will, however, hereinafter more fully ap-l pear.

The present application is a continuation-inpart of my copending application Serial No.

368,692, led December 5, 1940, now abandoned.

n the accompanying drawings there are shown for purposes of illustration several forms which the invention may assume in practice.

1n these drawings,

Fig. 1 is a plan View of a drill mechanism having incorporated therein one illustrative embodiment of the invention.

Fig. 2 is a side elevational view, with parts broken away, of the drill mechanism shown in Fig. 1.

Figs. 3 and 4 taken together constitute an enlarged view in longitudinal vertical section through the drill mechanism shown in Figs. 1 and 2 Fig. 5 is a transverse sectional View through the drill mechanism and taken on the plane of the line 5 5 of Fig. 3.

Fig. 6 is a detail sectional view taken on the line 6-6 of Fig. 3.

Fig. 7 is a transverse sectional view taken on the line 1-1 of Fig. 4.

Fig. 3 is a transverse sectional View taken substantially on the line 8--8 of Fig. 3.

Fig. 9 is a fragmentary sectional view taken on a plane corresponding to the plane of Fig. 3, and showing a modication of the invention.

Fig. 10 is a cross sectional view taken substantially on the plane of the line Ill-I9 of Fig. 9.

Fig. 11 is a longitudinal sectional view showing another modiiication of the invention.

Fig. 12 is a cross sectional view taken substanu tially on the plane of the line I2-I2 of Fig. 1l.

Fig. 13 is a side elevational view of a drilling apparatus, with parts shown in longitudinal section, having still another modication of the invention embodied therein.

Fig. 14 is a cross sectional view taken substantially on line I4--I4 of Fig. 13. f

Fig. 15 is a longitudinal sectional view showing the rear portion of the feeding means for the drilling apparatus shown in Fig, 13.

Fig. 16 is a cross sectional view taken substantially on line I--I of Fig. 13.`

In the illustrative embodiment of the invention shown in Figs. 1 to 8 inclusive, a rotary type drilling apparatus generally designated I is mounted on a supporting and guiding structure, generally designated 2, and has associated therewith drill feeding means generally Vdesignated 3 and feed control means generally designated 4.

The drilling apparatus I includes a bit rotating motor 6 carried by a rear head member 1 which is slidably guided on the supporting and guiding structure 2 in a manner that will shortly be described. The motor is herein of the high speed electric type and includes a casing 8 provided with front and rear heads 9 and I0 held in assembled relation with respect to the casing by usual tie bolts II. The motor has a usual eld I3 and an armature rotor I4, the latter having a shaft I5 which is journaled in bearings I3, I9 suitably supported in the motor heads. Attached to the forward end of the shaft I5 is a chuck I8 for receiving the shank of a hollow dri11 rod I9 which carries a drill bit20. The rear motor head IB has a rearward cylindric projection 22 mounted for limited rotation in ball bearings 23 supported within a bore 24 formed in the head member 1. The bearings 23 are retained in the bore 24 by means of a retaining ring 25 secured, as by screws 23, to the head member 1; and the cylindric projection is held against axial displacement with respect to its bearings by means of an end plate 21 secured, as by screws, to the projection 22. Extending through a bore in the shaft I5 is a liquidV conducting tube 28 which is threaded at its rear end within a member 29 secured to the rear head member 1, and cleansing liquid is supplied through a passage 3E) in the member 29 to the tube 28 where it is conducted to the hollow drill rod and through the latter to the drill holel Attached to the rear end of the shaft I5 is a member 32 fitting closely around the tube 28 and having an annular flange engaging an annular flange on the end plate 21 to provide a seal preventing any cleansing liquid escaping around the end of the tube 28 from passing to the bearings I3 in the rear motor head and to the motor windings. A passage 33 in the member 29 connects the space surrounding the rear end oi the tube to a vent passage 34 so that any liquid escaping around the end of the tube may drain away. The structure so far described, except for the rear head member 1, is similar to that disclosed in a copending application to one Carl E. Dittmer, Serial No. 328,737, now matured into Patent No. 2,296,273, patented September 22, 1942, and further description of the same herein is accordingly unnecessary. The rear head member 1 is provided with a depending portion 36 that projects within a trough-like member 31 of the supporting and guiding structure 2, as shown in Figs. 3 and 5. Formed on the sides of the depending portion are anges 39, 39 which are slidably received in

grooves

49, 49 in the sides of the member 31 for guiding the drilling apparatus as it moves along the supporting and guiding means.

Referring to the drill feeding means, it will be noted that there is provided a feed screw 42 extending longitudinally through the trough-like member 31 in parallelism to the grooves 49, and the feed screw is journaled at its forward end in a plate 43 extending transversely ofthe member 31 and at its rearward end in a housing 44, as shown in Figs. 3 and 4. The plate 43 and the housing 44 are held in fixed positions to the ends of the member 31 by tie rods 46. Keyed to the feed screw at its rearward end is a worm wheel 41 meshing with a worm gear 48 that is keyed to a shaft/49 extending transversely through the housing 44 and journaled in the sides of the housing as shown in Fig. 7. Attached to a side of the housing, as by screws 53, and in alinement with the shaft 49 is a motor 5I, shown herein as an electric torque motor, having its rotor attached to an end of the shaft 43 projecting through the side of the housing. A switch box 52 is attached, as by screws 53, to the rear end of the housing 44 and contains a switch having a control handle 54 for controlling the flow of electric current through

lines

55 and 53 to the motors 6 and 5I, respectively. The feed screw extends, as shown in Fig. 3, through the depending portion 39 of the head member 1, and a feed nut 58 having a head 59 engaging surfaces on the head member 'l is clamped firmly to the head member in threaded engagement with the feed screw by a clamping nut 39. AS the feed nut is held against bodily and rotative movements relative to the head mem-l ber 1 there will be, during rotation of the feedv screw by the' motor 5| through the worm gear 48 andthe worm wheel '41, a feeding or a retractive movement of the drilling apparatus relative to the supperting and guiding structure 2. Formed on the member 31 of the supporting and guiding structurels a swivel plate 82 adapted for clamping in the saddle mounting of a conventional rock drill support. With the drilling apparatus supported at the face of material to be drilled and a rotation of the feed screw in a direction to effect movement of the ldrilling apparatus toward the material, there will be, on engagement of the ma-A terial by the drill bit and on rotation of the drill bit by the motor 6, a drilling of the material. If the drill bit is unable to cut its'way as rapidly as the drilling apparatus is fed toward the material there will be a binding of the bit with a resulting increase in the load on the bit rotating motor, and if the load is rincreased sufficiently the bit rotating motor may be stalled or the bit may be damaged. To prevent stalling of the motor or damage to the bit, there is provided the feed control means generally designated 4.

The feed control means e, as shown in Fi'g- 3, includes a sleeve 84' surrounding the feed screw and having splines 65 slidably` fitting within Igrooves S6 formed in the feed screw, as shown in Fig. 8, so that the sleeve is held against rotation relative to the feed screw but is permitted to move longitudinally thereof. The sleeve 64 is rotatably supported at its front and rear ends, respectively, within an opening in the front wall of a recessed member S8 which is attached to the head member 1, as by screws 69, and within an opening in a cover plate 10 attached to the recessed member, as by screws 1|. The sleeve is held against bodily movement relative to the head member and longitudinally of the feed screw by

split rings

12, 12 engaging the recessed member |58 and the cover plate 10. Held to the sleeve 64 are friction elements in the form of brake disks 13 interleaved with other friction elements in the form vof brake disks 14 held within the recessed member 68 against rotation relative to the latter in any suitable manner. Surrounding the feed screw is a shipper 'ring 15 having lprojecting, members 16 extending through openings in the front wall of the recessed member 88 into engagement with one of the brake disks. Formed in the head member 1 i's a chamber 11, and extending through this chamber transversely of the drilling apparatus is a rod 18 having its ends supported by the side walls of the chamber, as shown in Fig. 5, A shipper arm 19 is pivotally supported at one of its ends 4by the rod 18 and at its other end is provided with forkeclarms 80 having projecting portions 8| Vfitting within an annular groove 82 in the shipper ring 15. The shipper arm is provided between its endsl with an elbow-like bend 84, and fixed to the end plate 21 of the drillro-l tating motor is a cam device 85 having a cam surface 86 for engaging the elbow 84 and forcing the shipper arm to vswing about its pivot and effect a pressing together of the brake disks through the shipper ring when the drill rotating motor is caused to rotate in the bearings 23 in a countereclockwise direction as viewedl in Fig. 5. Threaded into an opening in the end plate 21 is'a ypin 88 having its outer `end projecting a short distance from the rear surface of the plate, and a plunger 89 is reciprocable within a sleeve-shaped member 90 which is threaded into an opening in a side of the head member 1, andthe plunger is 6 jectig portion of the pin 88. The force of the spring 95| is such that it prevents the motor'eld I3 and casing 8 from turning in the bearings 23 ih a countereclockwise direction as viewed in Fig.

. 5, Vduring norma1 drilling operations, but on ine crease` of the motor load above a safe limit the motor casing turns against the force of spring-9| and causes the cam device 85 to swing the shipper arm 19 about its pivot and effect an application of the brake disks, slowing down or stopping the drill'fee'd.

The mode of operation is 'as follows: The swivel plate 32 of the' -supporting and guiding means is clamped ih the saddle mounting of a drill support at the face .of the work and the 'switch control handle 54fis operated to close the switch and sup'- ply current to the drill rotating motor 6 and to the drill feeding motor 5|. The motor 5| is run in a direction to cause the feed screw 42 to be driven through the worm gear 48 and the worm wheel 41 in such 'a way that the drilling apparatus will be fed` toward the work due to the engagement of the non-rotatable feed nut 58 with the feed screw. As the drill bit is moved into engagement with the work, drilling will take place, and if the load on the drill rotating motor is not too great the body of the motor will be held against rotation in the bearings' 23 by the spring 9| forcing the plunger 89 against the pin 88. If the feeding pressure is such that the drill bit 20 is unable to cut its way without increasing abnormally the load on the bit rotating motor, there will be a turning ofthe motorfin the bearings 23 against the force lof spring 9|, 'and the cam device 85 will effect a swinging of the shipper arm 19 in a direction to Cause the brake disks 13 and 14 to be pressed together and slow down or stop the rotation of the feed screw in a feeding direction.

' There is shown in Figs. 9 'and 10 a modincation of the invention in which a feed nut 95 is rotatably suppo'rted at its front end by a rbearing 96 carried by a depending portion 91 lof the lhead member 1, and rotatably supported at its rear end by a bearing 98 carried by the cover plate 10. The feed nutthreadedly engages a feed screw l 00, andv surrounding the feed nut are friction elements 0| held against rotation relative to the nut 'and interleaved with friction elements `|02 which are held within the recessed member B8 against rotation relative to the latter, in any suitable manner. A shipper ring |03 surrounds the feed nut and has lingers |04 projecting through openings in the member 68 into engagement with the friction disks. A spring |05 surrounding the forced by a spring 9| against theside of .the pro- 75 feed nut acts between the depending portion 91 and the shipper ring to urge the latter in a direction to press the friction elements into engage-'- ment with each other. Pivotally supported within the chamber 11 on a rod |06 is an arm |01 vhaving forked portions |08 which carry projecting portions 09 extending into an annular groove ||0 in the' ring |03. The arm |01 extends above its pivotal supporting rod, "and the upper portion of the arm is engageable by the cam device and caused to swing in a clock-wise direction by the latter when the drill rotating motor is overloaded. It will be seen that the feed nut' will be held against rotation by the friction elements during normal drilling, but, as the drilling loads become excessive, the arm |01 will be swung in a direction to force the shipper ring out of engagement with the friction elements vso that the braking force is removed, or at least decreased, and the feed nut'rotates with the feed screw, decreasing or-s'topping thefeed. Y Y Y In Figs. 11 and 12 there is shown'a modifica-l tion in which a feed screw ||5 is supported by a guide member i6 and held against rotation relative to the latter. Slidably mounted on the guide member He is a head member, generally designated H1, to which the drill rotating motor 6 is operatively connected, as described in the first form `of the invention. The head member ||1 has a depending section ||8 rotatably supporting a feed nut ||9 in threaded engagement with the feed screw ||5. The feed nut is provided with teeth |20 which mesh with the teeth -of a worm |2| keyed to a shaft |22 supported by and extending transversely of the head member ||1. Fixed to the shaft |22 is a gear |23 meshing with a gear |24 fixed to a shaft y|25 supported by the head member. Also connected to the shaft |25 is a bevel gear |21 meshing with a bevel gear |28 fixed to one end of the power shaft |29 of a motor |30 secured, as by bolts |3l, within a chamber |32 in the head member ||1. Surrounding the power shaft |29 adjacent its other end are friction elements |34 held against rotation relative to the power shaft and interleaved with friction elements |35 which are held against rotation relative to the head member. A plate member |36 is provided with projecting portions |31 which are adapted to press the friction elements together when the plate member is moved in a rearward direction. A lever |38 pivotally supported at |39 is adapted to be swung by the cam device 85 to apply pressure to the plate |36 to force the plate member in a direction to press the friction elements together when the drill rotating motor is overloaded. During normal drill loads, the motor |30 operates to drive the feed nut ||9 through the bevel gears |28, |21, the shaft |25, the gears |24, |23, the Shaft |22, the worm gear |2|, and the teeth |20 on the feed nut. When' the drill rotating motor becomes overloaded, it rotates slightly relative to the head member ||1 and causes the cam device 85 to act on the lever |38 to force the plate member |36 in a direction to press the friction elements together. The rotation of the power shaft |20 is then resisted and caused to slow down, thereby reducing the rate of rotation of the feed nut.

In'Figs. 13 to 16 there is shown another modi* cation in which a supporting and guiding member |40 is shown ported and held in a xed position, as by bolts |42, operatively connected to the head member in a manner similar to that described in the first form zof the invention, but projecting rearwardly from the head member, is a drill rotating motor 6. In this case, a shaft |i4 extends thr-ough the head member |4| and axially through vthe rotor of the drill motor. Grooves |45 formed in the shaft are adapted to receive keys fixed to the rotor so that the shaft will be caused to rotate with the rotor but may move axially relative to the rotor. As in the rst form of the invention, a feed screw M6 is rotatably supported by the member |40 and is caused to be rotated through a worm wheel 41 keyed to the feed screw and mesh-v ing with aL worm gear 48 which is fixed to a shaft 49 driven by a motor 5|. A switch 52 having a manually operated lever '5 is adapted to control the supply of current to the motors 6 and 5|.

Surrounding the feed screw is a sleeve-shaped member |50 having splines fitting within grooves in the feed screw so that the sleeve member must turn if the screw turns. The sleeve'mernn ber is rotatably supported at one end in the wall of a recessed member |52 attached to a de endn on which a head member |4| is suping portion |53 of the head member |4|,V and is rotatably supported at its other end in a cover plate |54 attached to the recessed member, as by screws |55. Held to the sleeve member are friction elements |56 interleaved with friction elements |51 held within the recessed member against rotation relative to the latter. A shipper ring |58 is provided with projecting portions extending through openings in the recessed member for pressing the friction elements together, and an arm |60 is pivotally supported by the head member |4| and is adapted to be swung by the cam device in a direction to move the shipper ring toward the friction elements.

As the feed screw is rotated by .the motor 5|, the feed nut moves along the feed screw and causes the drill rod to be fed by reason of its connection to the feed member |63. If the load on the drill rotating motor becomes too great, the motor rotates relative to the support member |4| and actuates the arm |60 through the cam device 85, pressing the friction elements together and resisting rotation of the Vfeed screw.

As a result ofV this invention there is provided an improved feed control means for a rotary type drilling apparatus. It will be noted that as a result of the improvedfeed control means the rate of drill feed may be gradually reduced until the feeding of the bit is completely stopped, when the load on the bit rotating motor increases beyond a safe limit. By means of the improved feed control means there is obtained protection for the drilling apparatus and an automatic regulation of the feeding pressure, so that there may be a drilling of the material at a maximum safe rate. Other advantages of the invention will be clearly apparent torthose skilled in the art.

While there are in this application specifically described several forms which the invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration and that the invention may be further modified and embodied in Various other forms without Vdeparting from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a drilling apparatus, in combination, a drill rotating motor, feeding means for said drill rotating motor comprising cooperating feeding elements, one of which is rotatable and the other continuously held against rotation, power means the sourceof operating energy for which is separate from said drill rotating motor for rotating said rotatable element, and means responsive to changes in resistance to rotation of said drill rotating motor for automatically controlling the rotation of said rotatable element.

2. In a drilling apparatus, in combination, a drill rotating motor, feeding means for said drill rotating motor comprising 4cooperating feeding elements, Honeof which is rotatablean dv the other continuously held against rotation, .said element continuously held vagainst rotation being ,carried by said drill rotating motor'forniovement therewith, power means the source of operating energy Kfor which is separate 'from :said drill .rotating motor for vrotating said rotatable element, `and means responsive tochanges rin resistance to Yrotation of .said drill 'rotating motor and Aoperative when the resistance exceeds ia predetermined amount for automatically controlling the rotation'of said rotatableelement. f

3.. In a drilling apparatus, in combination, -a .drill rot-ating motor, ysupporting Y 'and guiding means for said ;motor,means forfeeding-said motor along said'supporting and guiding-meanscomprising cooperating -feedi-ng elements, of which one is rotatably mounted, respectively-carried by said motorV and said Supporting and guiding means, and-'a feed motor for rotating'said rotatable feeding element, Iand' means responsive to changesl in Vresista-nce to rotation of-said'drill rotating motorand operative when the resistance exceeds a-predetermined-amount for automatically increa-sing the-resistance to rotation of said rotatable element.

4. InY a drilling apparatus, in combination, a drill rotating ymotor, supporting and guiding means for said motor, Ymeans-for feeding said motoralong said supporting and guiding meanscomprising cooperating feeding elements, 4of which oneis rotatably mounted, respectively carried by said" motor and said supporting and guiding means, and means lforcontrolling therateof feed of said motor comprising brakedisksrotating with said rotatable feeding elementland movablelongitudinally thereof, .brake `disks non-rotatably supported for movement with said motoralong said supporting and guiding means .and interleaved with said first ymentioned brake disks, andmeans actuated by said motor on a predetermined in.- crease in ,load on .the latter `for pressingsaid first and-secondmentioned brake disksinto frictional engagement with each other.

5, ln a-drilling apparatus,v in combination, a

drill rotating motor, supporting and, guiding means for said `motor, meansA for, feeding said ,motor alongsaid supporting and guiding means comprising .cooperating feedingy elements, of whichv one isv rotatably mounted, respectively Carried by Sad motor and said supportingand guiding means, means for rotating said rotatable feeding element, and means for controlling the rate of feed of said motor comprising a frici tion element rotating with said rotatable feeding element and movable longitudinally thereof, a friction element non-rotatably supported for movement with said motor along said supporting and guiding means, and means actuated bv said motor on a predetermined increase in load on the latter for pressing said yfriction elements together, thereby resisting rotation of said rotatable feeding element.

6. In a drilling apparatus, in combination, a i

rotary drilling motor for rotating a drill bit, supporting and guiding means for saidm'otor, said motor being mounted on said supporting and guiding means for limited rotary movement relative theretdmeans for feeding said motor along said supporting and rguiding means comprising feeding elements, of which one is rotatably mounted, respectively carried by said motor and said supporting and guiding means, and means lfor controlling the rate of feed of said motor 1,0 comprising a friction element rotating with said rotatable feeding element and movable longitudinally thereof, a friction'element non-rotatably supported for movement with said motor along said supporting and guiding means, and means for pressing said friction elements together including a member actuated by said motor on rotation of the latter relative to said supporting and guiding means.

7. In a drilling apparatus, in combination, a rotary drilling motor for rotating a drill bit', supporting andguiding means for said motor, said moto-r being mounted on said supporting and guiding means for limited rotary movement relative thereto, means for feeding said motor along said supporting .and guiding means comprising feeding elements, of Which one is rotatably mounted, respectively carried by said motor and said supporting rand guiding means, and means for controlling the rate of feed of said motor -comprising a friction element rotating with said rotatable' feeding element and movable longitudinally thereof, a friction velement non-rotatably supported for movement with said motor along said supporting and guiding means, and means for pressing said friction elements together including a member pivotally connected at one end to saidmotor supporting means and engaging one of said friction elements at its other end, and cam means Yiixed to said motor and operative on rotary movement of said motor relative to said supporting and guiding means due to overloading of the motor forswinging said pivoted member in a direction to engage said friction elements.

8. In a drilling apparatus, `in combination. a rotary drilling motor for rotating a drill bit, supporting and guiding means for said motor, said motor being mounted on said-supporting and guiding means for limited rotary movement relative thereto, feeding Ameans for said drilling motor comprising feeding elements, of Whichfone is rotatably mounted, respectively carried by said motor and said supporting and guiding means, said feeding elements eifecting feeding of said drilling motor on `relative rotation therebetween,

lmeans for rotating said rotatable element, and

means including` friction elements controlled by the rotary 'movement of said motor relative rto said supporting and guiding means due to overloading Aof the motor for automatically controlling the rotation of said rotatable feeding element.

'9. In a drilling apparatus, in combination, a drill rotating motor, feeding means for said drill rotating motor comprising cooperating feeding elements interengaged IWith each other and one of which is rotatable relative to the other to effect feed, afeed motor for rotating said rotatable element, and means controlled by the 'torque load changes on said -drill rotating motor and operative when the torque load exceeds a predetermined amount for automatically increasing the resistance to rotation of said rotatable-element.

l0. In a drilling apparatus, va rotary drilling motor for rotating a -drill bit, motor operated feeding mechanism `for Said drilling motor including elements operative on relative rotation to effect feed of said drilling motor, means for varying the resistance to rotation of certain of said elements and causing avariation in the relative rotation thereof, and means for actuating said last mentioned means automatically variably in proportion -to excesses in torque above a predetermined amount exerted by said drilling motor.

11. In a drilling apparatus, in combination, a rotary drilling motor for rotating a drill bit, said rotary drilling motor having one of its elements connected in driving relation with a drill bit and another element, between'which and the first a rotary reaction takes place when said motor is running, supported for limited rotary movement, feeding means for said motor including cooperating elements coacting on rotation of one of the same to effect motor feed, braking means for said last mentioned element, and operative connections between said second mentioned motor element and said braking means for actuating saidv braking means automatically when an eX- cessive torque is exerted by said motor.

12. In a drilling apparatus, in combination, a drill rotating motor, feeding means for said drill rotating motor comprising cooperating feeding elements, of which one is rotatably mounted, means for rotating said rotatable feeding element to effect feed, means for resisting rotation of said rotatable element, and means responsive to the load changes on said drill rotating motor for controlling said resisting means to vary the resistance to rotation of saidl rotatable element, said last mentioned means being operative at predetermined load increases on said drill rotating motor for effecting a slowing down of said rotatable element to decrease the rate of feed.

13. In a drilling apparatus, in combination, a drilling motor for rotating a drill bit, feeding means for the drill bit including a rotatable feeding element, frictional resistance means for retarding the rotation of said rotatable feeding element, and means for automatically regulating said frictional resistance means to vary the rate of feed in accordance with variations in resistance to rotation of the drill bit,

14. In a drilling apparatus, in combination, a drilling motor for rotating a drill bit, feeding means for the drill bit including relatively rotatable, coacting feeding elements and a feeding motor for effecting relative rotation of said elements, said feeding motor constituting the sole source of power for said feeding means, and means automatically responsive to torque load changes on the drill bit for controlling the rate of relative rotation between said feeding elements to vary the rate of feed.

15. In a drilling apparatus, in combination, motor-operated means for rotating a drilling implement for causing the same to effect its drilling function, feeding means for the drilling implement comprising cooperating feeding elements, one of which is rotatable and the other continuously held against rotation, power means the source of operating energy for which`is separate from said motor-operated means for rotating said rotatable feeding element to effect feed, and means responsive to changes in resistance to rotation of said implement-rotating-means for automatically controlling the rotation of said rotatable feeding element.

16. In a drilling apparatus, in combination, motor-operated means for rotating a drilling implement for causing the same to effect its drilling function, feeding means for the drilling implement comprising cooperating feeding elements, one of which is rotatable and the other continuously held against rotation, said element continuously held against rotation being mounted for movement with the drilling implement, power means the source of operating energy for which is separate from said motor-operated means for rotating said rotatable feeding element, and

means responsive to changes in resistance to rotation of said implement-rotating-means and operative when the resistance exceeds a predetermined amount for automatically controlling the rotation of said rotatable element.

1'7. In a drilling apparatus, in combination, motor-operated means for rotating a drilling implement for causing the same to effect its drilling function, supporting and guiding means for the drilling implement, means for feeding the drilling implement along said supporting and guiding means comprising cooperating feeding elements, of which one is rotatably mounted and the other is held against rotation, one feeding element adapted to move with the drilling implement and the other carried by said supporting and guiding means and relative to which the first is movable, said feeding means operative to effect feeding of the drilling implement on relative rotation of said feeding elements, and a feed motor for rotating said rotatable feeding element, and means responsive to changes in resistance to rotation of said implement-rotating-means and operative when the resistance exceeds a predetermined amount for automatically increasing the resistance to rotation of said rotatable feeding element.

18. In a drilling apparatus, in combination, motor-operated means for rotating a drilling irnplement for causing the same to effect its drilling function, feeding means for the drilling implement comprising cooperating feeding elements interengaged with each other and one of which is rotatable relative to the other to effect feed, and a feed motor for rotating said rotatable feeding element, and means controlled by the torqueload changes on said implement-rotating-ineans and operative when the toroue load exceeds a predetermined amount for automatically increasing the resistance to rotation of said rotatable feeding element.

19. In a drilling apparatus, a motor for rotating a drilling implement, feeding mechanism for the drilling implement includingr elements operative on relative rotation to effect feed of the drilling implement and motor operated means for effecting relative rotation of said elements, means for varying the resistance to rotation of certain of said elements so as to vary the relative rotation thereof, and means for actuating said last mentioned means automatically variably in proportion to excesses in torque above a predetermined amount exerted by said implement-rotating-motor.

20. In a drilling apparatus, in combination, motor-operated means for rotating a drilling implement for causing the same to effect its drilling function, feeding means for a drilling implement comprising cooperating feeding elements, of which one is rotatably mounted, means for rotating said rotatable feeding element to eifect feed, and means responsive to the torque-load changes on said implement-rotating-means for varying the resistance to rotation of said rotatable feeding element, said last mentioned means being operative at predetermined torque-load increases on said implement-rotating-means for eifecting a slowing down of said rotatable feeding element to decrease the rate of feed.

21. In a drilling apparatus, the combination comprising motor operated means for rotating a drilling implement, feeding means for the drilling implement including a torque motor adapted to exert a substantially constant feeding force, and means responsive to torque-load changes on said implement-rotating-means for automatically controlling .the transmission of the feeding forces from said torque motor to the drilling implement to regulate the rate of feed.

22. In a drilling apparatus, the combination comprising motor operated means for rotating a drilling implement, means for feeding the drilling implement including relatively rotatable mechanically interengaged feeding elements, and braking means responsive to torque load changes on said implement-rotating-means for automatically controlling the rate of relative rotation of said feeding elements to regulate the rate of feed.

23. In a drilling apparatus, the combination comprising motor operated means for rotating a drilling implement, means for feeding the drilling implement including a torque motor ladapted to exert a substantially constant feeding torque, frictional means for resisting the operation of said torque motor, and means responsive to torque-load changes on said implement-rotatingmeans for automatically controlling the loading of said frictional resistance means to regulate the rate of feed.

24. In a drilling apparatus, the combination comprising motor operated means for actuating REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 535,451 Meissner Mar. 12, 1895 1,087,089 Trotter Feb. 10, 1914 556,502 Hebgen Mar. 17, 1896 FOREIGN PATENTS Number Country Date 229,867 Germany Jan. 10, 1911 243,641 Germany Feb. 19, 1912 21,771 Great Britain Oct. 30, 1914