US2339801A

US2339801A - Drilling apparatus

Info

Publication number: US2339801A
Application number: US373586A
Authority: US
Inventors: Win W Paget
Original assignee: Sullivan Machinery Co
Current assignee: Sullivan Machinery Co
Priority date: 1941-01-08
Filing date: 1941-01-08
Publication date: 1944-01-25
Anticipated expiration: 1961-01-25

Description

w. w. PAGET DRILLING APPARATUS Jan. 25, 1944.

Filed Jan. 8, 1941 s Sheets-Sheet 1 g Q Q 5 W. W. PAG ET DRILLING APPARATUS Jan. 25, 1944.

3 Sheets-Sheet 2 Filed Jan. 8, 1941 Patented Jan. 1944 DRILLING APPARATUS Win W. Paget, Michigan City, lull, assignor to Sullivan Machinery Company, a corporation of Massachusetts Application January 8, 1941, Serial No. 373,586

24 Claims.

This invention relates to drilling apparatus, and more particularly to improvements in rotary drilling apparatus of the high speed type especially designed for use in boring holes in relatively hard materials such as hard rock or the like.

An object of this invention is to provide an improved drilling apparatus. Another object is to provide an improved drilling apparatus having improved feeding means and improved means for controlling the feeding means. A further object is to provide a fluid actuated feeding means for a rotary drilling apparatus having improved means responsive to the resistance to rotation for automatically controlling the feeding pressure.

Still another object is to provide improved means for controlling the flow of motive fluid to the.

feeding means and the venting of fluid from the feeding means. A further object is to provide an improved rotary drilling apparatus of the high speed type having improved means for automatically controlling the feeding pressure on the drill bit so as to maintain an automatically controlled and regulated feeding pressure during the drilling operation. A still further object is to provide an improved feed controlling means having difierent degrees of responsiveness to different degrees of resistance to drill bit rotation whereby difierent feed controlling functions may be effected. Still another object is to provide an improved feed .controlling means operatively connected in the drive between'the bit rotating motor and the drill rod whereby relative controlling movement between the parts may occur when certain drilling conditions are encountered so that the drilling pressure may be automatically regulated in an improved manner. A further object is to provide an improved feed controlling means embodying relatively movable controlling connections between a motor driven element and a cooperating element driven thereby, the latter element being operatively connected to the drill bit, whereby variations in the resistance to drill bit rotation automatically efiect relative motion between the said elements,- and the said controlling connections embodying means for transmitting such relative motion to a feed controlling element. A still further object is to provide an improved feed controlling means automatically responsive to resistance to drill bit rotation for regulating the flow of motive fluid to the feeding means within certain degrees of resistance to drill bit rotation, and for automatically interrupting suchflow when the resistance to drill bit rotation reaches a predetermined point, and embodying means for automatically venting the feeding pressure when such point is, for any reason, exceeded. A still further object 'is to'provide an improved torque-controlled valve means having improved control means responsive to torque variations resulting from changes in load on the drill bit rotating means, for automaticallycontrolling the feedings means. A still further object is to provide an improved torque-controlled valve means having improved operating means whereby 'the valve position may 'be automatically changed in accordance with torque changes on the drill rotating means, in an improved manner. These and other objects and advantages of the invention will,- however, hereinafter more 'fully appear.

In the accompanying drawings there is shown for purposes of illustration one form which the invention may assume in practice.

In these drawings:

Figs. 1 and 2, when taken together, constitute a view in longitudinal vertical section through an illustrative embodiment of the improved drilling apparatus, parts being shown in elevation to facilitate illustration.

Fig. 3 is an enlarged fragmentary sectional view taken on the plane of Fig. 1, illustrating the improved feed controlling means.

Fig. 4 is a detail vertical sectional view taken substantially on line 4-4 of Fig. 3.

Fig. 5 is a .detail sectional view taken on line 55 of Fig. 4.

Fig. 6 is a detail sectional view illustrating one of the fluid conducting passages of the feeding means.

Fig. 7 is an enlarged horizontal sectional view taken substantially on line 1-1 of Fig. 1, illustrating the manual control valve. 4

Fig. 8 is a detail sectional view, taken substan tially on line 8-8 of Fig. 7, showing and below the plane of Fig. 7.

Fig. 9 is a detail vertical sectional view taken on line 9-9 of Fig. 4.

Fig. 10 is a vertical sectional view taken on line Ill-10 of Fig. 3, illustrating the torque-conparts above sectional view ftaken substantially on the plane including line l3.l3 clv Fig. 12.

Fig. 14 is a atic view illustrating the fluid system and the associated control means.

In this illustrative embodiment of the inventionthere is shown a. rotary drilling apparatus of the high speed type especially designed for use in boring holes in relatively hard rock or the like and adapted to use with abrasive type bits, commonly known as diamond bits. The drilling appaartus may be of the same general type as that disclosed in my copending application Serial No. 322,267, filed Mar. 5, 1940, since matured into Patent No. 2,288,543 dated June 30, 1942, and as a whole comprises bit rotating means, generally designated I, fluid actuated feeding means, generally designated 2, manual feeding means, generally designated 3, and supporting and guidin means, generally designated 4.

The supporting and guiding means 4, which is similar to that shown in the copending application above referred to, comprises a trunnion support 5 having a swivel plate 6 adapted to be secured in the saddle mounting of a conventiona1 rock drill support.

The fluid actuated feeding means 2 likewise is similar to that shown in the'aforesaid copending application and comprises a reciprocable feed, cylinder I slidably guided in a bore 8 in the trunnion support and containing a reciprocable feed piston 9 having a tubular piston rod l extending forwardly through paekines ll carried by the front head l2 of the feed cylinder. The cylinder head I2 is suitably secured to the feed 0371- inder and closes. the front end of the cylinder bore, while the rear end of the cylinder bore is closed by a rear cylinder head l3 likewise suitably secured to the cylinder. The'front and rear cylinder heads are engageable with the end surfaces of the trlmnion support 4 to limit reciprocable movement of the feed cylinder in the trunnion support bore. Secured to the front end of the feed piston rod I0 is a head member H which closes the front end of the piston rod bore, and the rear end of the piston rod bore is closed by a head element l5 which constitutes an element of the feed piston 3. The feed piston is double acting and has packings l3 sealingly engaging the walls of the cylinder bore and secured in position by the members I! and [8, in turn held in position on the head element l5 of the piston rod between a shoulder l9 and an end lalsate 20 detachably secured to the head element Now referring to the manual feeding means 3, it will be noted that secured within the trunnion support 5 is a tube 2| having its axis arranged in parallelism with the feed cylinder axis, and extending longitudinally through this tube and rotatably mounted in depending bosses integral with the front and rear cylinder heads l2 and I3 is a tubular feed. screw 22 coacting with a non-rotatable feed nut 23 secured within the trunnion support. The forward end of the rotatable feed screw is fixed against axial displacement with respect to the feed cylinder and'extends rearwardly through the rear head l3 and has secured thereto, at its rear end, a hand crank 24 having a grasping portion 25. Carried by the hand crank is a suitable plunger lock 26 engageable within a locking recess 21 in the rear cylinder head for locking the feed screw against rotation during automatic feeding of the drill.

'Ihreadedly secured at 3| within this control head is a member 3| having a sleeve portion fittin within the bore of the feed screw at the forward end of the latter, and secured, as by welding at 32, to this sleeve portion is a tube 33 extending centrally within and in telescopic relation with the feed screw, in the manner shown in Figs. 1 and 2. The tube 33 has a sliding fit with the walls of the bore of the feed screw and serves to maintain the feed cylinder against rotation within its bore on the trunnion support and in efiect acts as a lateral sliding guide for the drill. The manual feeding means and the sliding guide structure are likewise clearly described in the application mentioned above.

The drill bit rotating means I comprises a rotary motor 35, herein a high speed electric motorof the totally enclosed type, comprising a stator casing 36 provided with front and

rear heads

31 and 38, the latterbeing formed preferably integral with the control head 29, as shown in Fig. 1. The motor parts are held in assembled relation by tie bolts 39. Clamped in position within the motor casing by the front motor head is an inner head member 40, while clamped within a bore 4| inthe control head by the screws 28 are butting

head elements

42 and 43. The motor has a usual field 44 and an armature rotor 45, the latter being secured to an armature shaft 46. The forward endof this armature shaft is joumaled, in a manner to be later explained, within bearings 41 supported within the

front head members

31 and 40 and at its rear end within a bearing 48 supported within the head element 42. It is accordingly evident that the motor casing is rigidly secured to the control head, and electrical energy may be conducted to the windings of the motor from any convenient source through a conventional connector plug 49 mounted on the control head and connected through wiring 50 to an automatic switch 5! which is arranged in a chamber 52 in the control head for efiecting stopping and starting of the motor in the manner clearly described in the copending application above referred to. The forward end of the armature shaft is supported within a shaft 53 and through this shaft is journaled within the bearings 41, and the shaft 53 As above mentioned, the forward end of the feed piston rod l0 supports a head member l4 (-Fig's. 1 and 6), and rigidly secured, as by screws 28, to this head member is a control head 28.

carries a chuck 54 which receives the supporting means for the drill rod which carries the drill bit.

The means for supplying fluid, preferably liquid under pressure, to the fluid actuated feeding means 2 comprises a liquid supply chamber 55 formed in the control head 29, and liquid under pressure may be conducted to this chamber through a strainer 56 from a supply passage 51 formed in a head member 58 secured to the control head. Also formed in the control head 29 is a longitudinal bore 59 having arranged therein a ported valve bushing 60 in which a control valve 6| is reciprocably mounted. This valve is of the sliding spool type and is operated by a valve adlusting screw 62 engaging a non-rotatable nut 63 formed within the sleeve portion of the member 3|. The screw 62 is rigidly secured to an operating rod 64 which has sliding but non-rotatable telescoplc engagement with an operating rod (Fig. 2). The rod 65 extends rearwardly from within the tubular feed screw and is secured at its rear end to a control handle 66. It will thus be seen that by rotating the handle 66, the control valve 6| may be moved longitudinally within the valve bushing bore through the rotatable screw 62 engaging the non-rotatable nut 63, and by the provision of the telescopically arranged .to be described, into a bearing [23 in which the front end 29 interposed between the the feed piston 9 has reached its limit of forward feeding travel relative to the-feed cylinder I, the manual control valve GI may be positioned to supply liquid under pressure to the reverse feed passages to efiect retraction of the feed piston 9 within the feed cylinder I, and the feed cylinder may then be fed forwardly in its guide bore on the trunnion support into a new feeding position, and thereafter forward feeding movement of the feed piston under the actuation ofliquid under pressure may be resumed. Also, if desired, the bit rotating motor may be fed forwardly or rearwardly solely by the hand crank of the feed screw entirely independently of the flow of liquid under pressure to the feed cylinder. If, during forward feeding of the drill bit by liquid acting on the rear pressure area of the feed piston, it is desired to feed the feed cylinder forwardly within its guide bore relative to the trunnion support by means of the hand crankof the feed screw and so to move the feed cylinder forwardly relative to the piston,

the hand crank of the feed the operator turns screw so as toadvance the feed cylinder at arate greater than the rate of penetration of the drill bit, i. e. at a rate greater than the rate of the apparatus. This will obviously cause the normal feeding pressure on the drill bit to be increased, and, as a result, the torque on the bit rotating means to become excessive so that the torque-controlled valve means would be moved, by the improved torque reaction means shortly position to eflect venting of the liquid in the forward feed passages, in the same general manner as is described in the copending application mentioned above. Such venting of the liquid from the rear end of the feed cylinders enables manual feeding movement of the feed. cylinder relative piston, and the rate of manual cylinder advance is regulated by the capacity of the venting means.

The improved control means for the torquecontrolled valve means comprises a reciprocable member [20 splinai at IZI within a rearward hollow portion I22 of the shaft 53. Supported with.- in the shaft 53 at the rear of the member IN is. a of the motor armature shaft it: isiournaled,'and the motor shaft is: supported through this hearing by the shaft 53 which is journaled in the bearings ll. The reciprocable member 20 rotates; with the shaft 53 and has internal, spiral vanes or threads [25- which are interengaged with similar spiral vanes or threads [*25 formed externally on the front end of the. armature shaft. It is according- Iy evident that the member 28, due to its: threaded enga ement the motor shaft, moves axially relative to: the motor shaft upon relative rotation between the member [221! and the motor shaft. The motor shaft is centrally bored at $28;

and extending centrally through this bore a hollow operating rod 211.

flange [2t engageable with a. ball thrust bearing rod flange and an internal flange 30 on the member E28- The rear end of the operating rod is annularly grooved. at 131,- and pins 32 on a shipper yoke R3 are received in. the: rod. groove so that when; the rod is moved theshipper-yoke is swung about its to the feed This rod has: a front I Til the position shown in Fig.

pivotal mounting on a vertical pivot shaft I. The shipper yoke is'keyed to the shaft Ill and the latter is journaled in bearingssupported within bearing brackein I35 integral with the rear-head element 43. Fixed by a set screw I 36 to the pivot shaft [3i is a lever l3! which projects within an annular groove I38 on the valve tappet 90 (Fig. 5). When the load on the bit rotating means is normal, the spring 2 holds the tappet to the right, as shown in Fig. 10, and, as a result, the member I20 is held in its rearmost position on the motor shaft through the lever I31, shaft I34, shipper yoke I33, operating rod I21 and thrust hearing I29.

When the load on the bit rotating means exceeds a predetermined amount, i. e. if the resistance to drill bit rotation becomes excessive, relative rotation between the member I20 and the motor shaft occurs, thereby causing the member I 2!! to move axially in a forward direction'relative to the motor shaft, and, as a result, the valve tappet S0 is moved to the left in Fig. 10 through the operating rod, shipper yoke and lever against the tension of the spring 2. As the valve tappet ismoved to the left in Fig. 10, to the position shown in Fig. 11, the sleeve valve 88 is moved towards its seat or completely seated, thereby partially to close or completely to out 011. the flow of liquid under pressure from the passage TI to the forward feed passage I9. If the load on the bit rotating motor becomes even greater (which it might do despite the interruption of feeding liquid, were there application of excessive manual feeding pressure to the bit as above explained) i. e. if the resistance to bit rotation exceeds that which was previously predetermined as sumcient to warrant interruption of feeding, the member 52E will move slightly further forwardly axially relative to the motor shaft, thereby moving the valve tappet 9|! further towards the left, moving the valve stem 9! relative to the then seated sleeve valve 88 from the position shown in Fig. 11 to 12, and, as a result, the forward feed pasage I3 is vented through slot 99. ports I80, groove 88, ports 95, groove 9, ports 98, longitudinal passage 91', chamber [05, groove "it, exhaust slot ME and exhaust passages fill and [88. It is accordingly evident that variations in the load on the bit rotating means, due ordinarily to variations in the pressure at which the bit is forced to the work, will automatically efiect control of the flow of liquid to the forward feed passages'and interrupt the supply of liquid to the forward feed passages as overload of Simicient degree occurs, and on still greater overload vmt the forward passages. When the torque-controlled valve means is in the position shown in Fig. 12', the tappet engages the shock der "4 on the bushing 89? to preclude further movement of the tappet toward the left. During; overloading of the bitrotating means by the man-'- ual feeding means, the overload of the motor causes the. pressure on the tappet produced by the increased torque to: exceed the combined pressures exerted by the Springs 93 and I I2, thereby to cause the valve storm to move axially relative; to the then seated sleeve valve which permits the liquid trapped in the feed cylinder at the rear side of the feed piston to discharge through. the feed exhaust passages. This venting function is at all times under torque control so that varied rates of venting. adapted todifierent rates of manna]; feedpare obtained, and if the feed exhaust passages are of sificient capacity the speed at which the operator manually feeds the feed operating rods the valve may be operated irrespective of the position of the control head relative to the trunnion support. Communicating with the rear end of the bore of the valve bushing is an exhaust chamber 61 connected to an exhaust passage 68. Surrounding the valve bushing are grooves 69 and I connected by ports with the valve bushing bore. Groove 69 is the fluid supply groove and communicates with chamber 55 as shown in Fig. 1. Groove communicates with the forward end of the feed cylinder as later described. A chamber 1I also communicates through ports with the valve bushing bore, while communicating with the front end of the valve bushing bore is an exhaust chamber 12 communicating with an exhaust passage I3. Chamber II is communicable with the rear end of the feed cylinder, as later explained. The groove 10 is connected by a passage 14 in the control head (Fig. 1) with a passage 15 in the head member I4, the latter passage communicating with the interior of the feed piston rod I0. Ports 16 (Fig.

2 connect the interior of the feed piston rod with the feed cylinder bore at the front side of the feed piston 9. Liquid under pressure may be supplied to the cylinder bore at the rear side of the feed piston from the chamber II, when the latter is connected with the groove 69, through a passage 11, past a torque-controlled valve means, generally designated I8, to a forward feed passage 19 communicating with a passage 80 in the head member Il. Thepassage 80 communicates with a recess 8| which is in turn connected, by a liquid conducting tube 82 extending centrally through the feed. piston rod with the cylinder bore at the rear side of the feed piston (see Figs. 1, 2 and 6). The feed piston carries a packing 83 which sealingly engages the tube to prevent leakage. When the control valve 6I is inone position the forward feed passages communicating with the rear end of the feed cylinder bore at the rear side of the feed piston are connected to the supply groove, while the reverse feed passages communicating with the feed cylinder bore at the forward side of the feed piston are connected to the exhaust chamber; and when the position of the valve is reversed the forward feed passages are connected to exhaust while the reverse feed passages are connected to the supplv. It will thus be seen that under the control of the manual control valve 6| liquid under pressure may be supplied to the feed cylinder bore at either side of the feedpiston to effect forward or reverse feed as desired, and the manner in which theforward feed is influenced by the automatic torque-controlled valve means I8 will later be described.

The torque on the bit rotating means automatically regulates the flow of liquid under pressure through the forward feed passages under the control of the torque-controlled 'valve means above mentioned, thereby to control the feedin pressure on the drill bit. and when the torque on the bit rotating means exceeds a predetermined amount the forward feeding pressure may be vented. As shown in Figs. 10 and 11. secured, within a transverse bore 85 in the control head 29 is a valve sleeve 86 having a tapered annular valve seat 81 with whichthe tapered end of a sleeve valve 88 is engageable. Reciprocably guided within the bore of a bushing 89 is a valve tappet 90 having an integral valve stem 9|. The valve stem has a close sliding fit with the bore of the sleeve valve 88, and the sleeve valve is yieldingly held against a shoulder 92 on the valve stem by a coil spring 93. The sleeve valve has an internal annular groove 94 connectiblebyports 95' with a chamber 96 which surrounds the valve. Formed in the valve stem 9 I is an axial passage 91 connectible through ports 98 with the internal groove 94 in the sleeve valve in some positions of the latter relative to the valve stem but normally sealed by the inner wall of the sleeve valve. When the sleeve valve 88 is against the shoulder 92, as shown in Figs. 10 and 11, and the sleeve valve is open a predetermined amount, communication of the ports 95 with the chamber is cut off by the body of the sleeve valve, while when the parts are in the position shown in Fig. 12 with the sleeve valve seated, but not against the shoulder on the stem, the ports are in communication with the chamber 96 and with the ports 98. The valve sleeve 86 is transversely slotted at 99, and this slot is connected by a port I00 with the chamber 96. The opposite side of the valve sleeve is transversely slotted at IN, and

this slot is connected by a port I02 with an enlarged bore I03, the latter being communicable, under the sontrol of the sleeve valve, with the chamber 96. The passage 11 communicates'with.

the slot IOI, and the slot 99 communicates with the forward feed passage I9. As shown in Fig. 12, a longitudinal groove I04 on the exterior of the valve sleeve connects a chamber I05 at the outer end of the valve sleeve bore with a transverse slot I06 which is connected'by passages I01 and I08 with the exhaust. The valve stem 9| has a sliding fit with the valve sleeve bore, and packings I09 sealingly engage the valve stem to reduce the possibility of leakage. Any leakage of liquid along the valve stem may flow from the packing bore to the slot I06, as shown in Fig. 12. Threaded within one end of the valve sleeve bore is a closure plug IIO, while threaded within the opposite end of the valve sleeve bore is a plug I II with which the bushing 89 is integrally formed, and interposed between the later plug and the valve tappet is a coil spring II2 which constantly urges the tappet toward the right as viewed in Figs. '10 and 11. The coil spring is arranged within the bore of the plug III'. When the tappet is in the position shown in Fig. 10, it abuts the inner end of the valve sleeve 86, and when the tappet is in its extreme left hand position it may abut a shoulder II4 on the bushing 89. The pressure exerted by the spring II 2' is opposite to the direction in which the tappet is moved as a result of the torque reaction of the bit rotating means by the improved means shortly to be described, and the pressure exerted by the spring H2 is suflicient to hold the tappet against movement during normal full loaddrilling torque. The spring 93 is made of such strength that it will not yield and permit movement of the valve stem 9I relative to the valve sleeve 88, with resultant communication of the passages 95 with the chamber 96, until a definite overloading of the bit rotating motor occurs. The spring 93 is preferably made one quarter as strong as the spring H2 plus an amount sufficient to offset the changes due to the hydraulic pressure acting on the difference between the areas of the sleeve valve'and valve stem. Noting that additional compression of the spring II2 will also have to be efiected asoverload increases, it willbe apparent that a material overload, an excess desirably upwardsof twenty-five per cent of normal-full load,will'be necessary on the bit rotating tmotor before the slot 99 willbe connected to ven The bit rotating motor may be fed manually by The fluid actuated feeding means is capable of imparting a forward feeding pressure to the drill bit sufficient to overload the bit rotating motor, and in the event of any change in drilling conditions increasing above normal the torque requirements, and in the event of initiation of overloading of. the bit rotating motor due to excessive torque loads, the torque-controlled valve means is actuated in a manner above described, partially or completely to cut off flow of liquid to the forward feed passages, thereby to slow down or stop forward feed and preclude serious overloading of the bit rotating motor, and when the motor again operates at its normal load rating, forward feed is automatically resumed or brought back to its desired rate as the case may be. Thus the actual feeding pressure on the drill bit will always be kept at, or near, as an upperlimit, that required tokeep the bit rotating motor at its normal load rating, although the feeding pressure may be greatly reduced or entirely removed if conditions of drilling become more severe. It will be apparent that large increases in torque requirements will entirely interrupt-feeding liquid supply momentarily and that slighter increases will serve to throttle the feeding liquid supply,

and depending upon the pressure in the feed pressure supply line and the strength of the spring H2, the normal full load position of the sleeve valve 88 may vary.

Cleansing liquid may be supplied through the drill rods to the drill bit from the liquid chamber 55 to a passage [40 in the control head 29, and

this passage is connected to a liquid conducting tube Ml secured at its rear end to the control head and extending centrally through the operating rod I21 and the motor armature shaft 46, as shown in Figs. land 3. The front end of the tube on may terminate within the hollow rear= ward portion of the shaft 53.

As a result of this invention it will be noted that an improved drilling apparatus of the high speed rotary type is provided whereb holes may be bored in relatively hard materials such as hard rock or the like. Also it is evident that an improved torque-controlled regulating means is provided responsive to load changes on the bit rotating means whereby the flow of feeding pressure to the feeding means may be automatically regulated in accordance with variations in the resistance to drill bit rotation, and the feeding.

means maybe automatically vented when the load on the bit rotating means is caused to exceed av predetermined amount. It will further be evident that by the provision of the improved operating means for the torque-controlled valve means, the mounting structure for the bit rotating motor is not only simplified over previous known devices but also the controlling action is rendered more positive and direct. Other uses and advantages of the improved drilling apparatus will beclearly apparent to those skilled in the art.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing 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, the combination comprising a motor for rotating a drill bit, said "latter, operating medium actuated means for feeding the drill bit including a power operated feeding element subjectable to the action of .power medium to effect positively feed of the drill bit toward the'work during drilling, and means for regulating the supply of operating medium to said feeding means automatically in accordance with variations in resistance to drill bit rotation, said automatic regulating means having operating means operatively connected in the drive between said motor power shaft and said driven shaft and actuated on relative rotation between said shafts.

2. In a drilling, apparatus, the combination comprising a motor for rotating a drill bit, said .motor having a power shaft, feeding means for said drill bit and having limited rotary movement with respect to the motor power shaft and operative on such movement to effect a change in the supply of motive power to said feeding means.

3. In a drilling apparatus, the combination comprising a motor for rotatin a drill bit, said motor having a power shaft, feeding means for feeding the drill bit including a power operated feeding element subjectable to the action of power medium to effect positively feed of the drill bit toward the work during drilling, and means for regulating the supply of motive power to said feeding means automatically in accordance with variations in resistance to drill bit rotation, said automatic regulating means including operating means having acontrol member connected in driving relation between the motor power shaft and the drill bit, said control member having limited axial movement with respect to the motor power shaft produced by load changes on the drill bitand operative on such movement to effect a change in the supply of motive power to said feeding means.

4. In a :drilling apparatus, the combination comprising a motor for rotating a'drill'bit, said motor having a power shaft, feeding means for ing a control member connected in driving relation between the motor power shaft and the drill bit, said control member having limited rotary and axial movements with respect to the motor power shaft produced by load changes on the drill bit and operative on such movements to effect a change in the supply of motive power to said feeding means.

5. A drilling-apparatus comprising, in combidrill bit for rotating the drill bit in the same direction as said shaft, said operative connections yieldable upon predetermined increase in resistance to drill bit rotation, operating medium actuated feeding means for said drill bit, and means for controlling the supply of operating medium to said feeding means automatically in accordance with variations in the resistance to rotation of said drill bit, said controlling means operatively connected to an element of said operative connections between said drill bit and shaft and governed by relative movement between said shaft and drill bit on variation in resistance to drill bit rotation to preclude application of feeding pressures in excess of desired values to the drill bit.

6. A drilling apparatus comprising, in combination, a rotary drill bit, a motor having a power shaft for rotating said drill bit to cause the same to effect a drilling operation by a boring action, fluid actuated feeding means for said drill bit including amovable feeding element subiectable to the action of pressure fluid for positively feeding the drill bit toward the work during drilling, and means for controlling the supply of fluid to said feeding means, said controlling means including torque-controlled valve means, and operating means for said valve means operatively connected between said motor power shaft and thebit and operating automatically in accordance with variations in the resistance to rotation of said drill bit, to precludeapplication of feeding pressures in excess of desired values to the drill bit.

'1. Drilling apparatus as claimed in claim 5, characterized in that said means for controlling the supply of operating, medium to said feeding means includes an operating element having movement with respect to the motor power shaft as the resistance. to rotation of said drill bit varies. a

8. Drilling apparatus as claimed in claim 5, characterized in that said means for controlling the supply of operating medium to said feeding means includes an operating element having rotary movement with respect to the motor power shaft as the resistance to rotation of said drill bit varies. V

9. Drilling apparatus as claimed in claim 5, characterized in that said means for controlling the supply of operating medium to said feeding means includes an operating element having axial movement with respect to the motor power shaft as the resistance to rotation of said drill bit varies.

10. Drilling apparatus as claimed in claim 5, characterized in that saidmeans for controlling the supply of operating medium to said feeding means includes an operating element having axial and rotary movements with respect to the motor power shaft as the resistance to rotation of said drill bit varies.

11. Drilling apparatus comprising, in combination, a rotary drill bit, a motor having a power shaft for rotating said drill bit to cause the same to effect a drilling operation by a boring action, feeding means for said drill bit, and means for controlling the operation of said feeding 'means automatically in accordance with variations in the resistance to rotation of said drill bit to preclude application of feeding pressures in excess of desired values to the drill bit. said I 2,839,801 nation, a rotary drill bit, a motor having a power feed controlling means operatively connected to said motor power shaft and including an operating element connected for rotation with the drill bit and having connection with said motor power shaft permitting relative rotation between said operating element and said power shaft, said connection between said operating element and said power shaft compelling relative axial movement between saidoperating element and said power shaft upon relative rotation therebetween.

12. A drilling apparatus comprising, in combination, a rotary drill bit, a motor having a power shaft for rotating said drill bit, operative connections between said drill bit and said power shaft including'a driven element alined with said power shaft and rotatable thereby in the same direction therewith, feeding means for said drill bit, and means for controlling the operation of said feeding means, said feed controlling means operatively connected in the drive between said motor power shaft and said driven element and being adapted to operate automatically in accordance with the variations in resistance to drilling to preclude application of feeding pressures in excess of' desired values to the drill bit.

13. A drilling apparatus comprisin in combination, a rotary drill bit, a motor having a power shaft for rotating said drill bit, operative connections between said drill bit and said power shaft including a. driven element alined with said power shaft, feeding means for-said drill bit, and means for controlling the operation of said feeding means, said feed controlling means operatively connected in the drive between said motor power shaft and said driven element and being adapted to operate automatically in accordance with the variations in resistance todrilling to preclude application of feeding pressures in excess of desired values to the drill bit, said feed controlling means including an operating element having an axial splined connection with said driven element.

14. A drilling apparatus comprising, in combination, a rotary drill bit, a motor having a power shaft for rotating said drill bit, operative connections between said drill bit and said power shaft including adriven element alined with bit and means for controlling the operation of said feeding means, said feed controlling means operatively connected in the drive between said motor'power shaft and said driven element and being adapted to operate automatically in accordance with the variations in resistance to drilling to preclude application of feeding pressures in excess of desired values' to the drill bit, said feed controlling means including an operating element which constitutes a connection between said motor power shaft and said driven element by which the latter is driven in the same direction as the former and which element is movable relative to said power shaft and said driven element.

l5. A'drilling apparatus comprising, in combination, a rotary drill bit, a motor havinga power shaft for rotating said drill bit, operative connections between said drill bit and said power shaft-including a driven element alined with said power shaft, feeding means for said drill bit, and means for controlling the operation of said feeding means, said feed controlling means operatively connected in the drive between said motor power shaft and said driven element and being adapted to operate'automatically in accordance with the variations in resistance to drilling to preclude application of feeding pressures in excess' of desired values to the drill bit, said feed bination, a rotary drill bit, a motor for rotating said drill bit, said motor having a casing containing a rotor having a power shaft, feeding means for said drill bit for exerting a feeding pressure thereon irrespective of whether the drill,- ing apparatus is supported to drill holes above or below the horizontal, and means operatively connected in the drive between the motor power.

shaft and the drill bit for controlling the operation of said feeding means, said feed controllng means being adapted to operate automatically in accordance with variations in the resistance to drilling to preclude application of feeding pressures in excess of desired valuesto the drill bit.

17. A drilling apparatus comprisingrin combination, a rotary drill bit, a motor for rotating said drill bit to cause the same to effect a drilling operation by a boring action, said motor having a non-rotatable easing containing a rotor having a power shaft, feeding means for said drill bit, and means for controlling the operation of said feeding means automatically in ac-' cordance with variations in the resistance to drilling to preclude application of feeding pressures in excess of desired values to the drill bit,

said controlling means including torque-controlled regulating means and operating means therefor connected in driving relation between the motor power shaft and the drill bit and effecting rotation of the-latter in the same direction as the former.

18. A drilling apparatus comprising, in combination, a rotary drill bit, a motor for rotating said drill bit to cause the same to effect a drill ing operation by a boring action, said motor having a non-rotatable casing containing a' rotor having a power shaft, feeding means for the drill bit including a power operated feeding element subiectable to a feeding pressure for posisaid drill bit to cause the same to effect a drilling operation by a boring action, said motor having a non-rotatable casing containing a rotor having a power shaft, feeding means for the drill bit, and means for controlling the operation of said feeding means, said feed controlling means including means governed by variations in the resistance to drilling for precluding the application of feeding pressures in excess'of the desired values to the drill bit, and said last mentioned means including an element'movable to control the feeding pressure and means for moving said element operatively connected with said power shaft and turning as the latter turns but so constructed and arranged that relative motion proportional to the torque exerted by said power shaft in effecting drilling occurs between the same and said shaft, said element moving means having axial motion with respect to said power shaft.

has bothrotary and axial motions with respect to said power shaft. I

22. In a drilling apparatus, in combination, a motor for rotating a drill bit, said motor having a power shaft,driving connections between said motor power shaft and the drill bit including a driven shaft operatively connected to said power shaft for rotation in the same direction with relative rotation in opposite directions between said power shaft and said driven shaft to effect opposite changes in feeding pressure.

23. In a drilling apparatus, in combination, a motor for rotating a drill bit, said motor having a power shaft, driving connections between said motor power shaft and'the drill bit including a driven shaft operatively connected to said power shaft for rotation in the same direction with but also for rotation relative to the latter, fluid actuated, feeding means for the drill bit, and means for controlling the supply of operating fluid to said feeding means automatically in tively feeding the drill bit toward the workduring drilling, and means for controlling the operation of said feeding means, said feed controlling means including means governed by variations in the resistance to drilling for precluding application of feeding pressures in excess of the desired values to the drill bit, said last mentioned means including an element movable tocontrol the feeding pressure and means for moving said element operatively connected with saidpower shaft and turningas the latter turns but so constructed and arrangedthat relative motion proportional to the torque'exerted by said power shaft in effecting drilling occurs between the same and said shaft.

19. Drilling appaartus as claimedin claim 18,

characterized in that said means between which and said power shaft there occurs relative motion proportional to the torque exerted by the power shaft for effecting drilling has rotary motion with respect to said power shaft.

20. Drilling apparatuscomprlsing, in combination, a rotary drill bit, a motor for rotating accordance with the resistance to drill bit rotation, said feed controlling means including means operatively connected to said driving connections 5 and actuated on relative rotation between said to cause said coaxial member to rotate in the same direction as said power driven member but yieldable to permit limited relative rotation between them as the resistance to rotation of said second member increases under increased resistance to drilling, means for feeding the bit as the same is rotated by the second member, and means governed by the relative rotation between said members for predeterminedly varying the feeding force exerted by said feeding means.

wm w. mom.

21. Drilling apparatus asclaimed in claim 20, characterized in that said element moving means