US2214753A - Feeding device - Google Patents

Description

F. E. slNcLAl'R Sept. 17, 1940.

` FEEDING DEVICE 3' Sheets-Sheet l Original Filed Dec. 27, 1935 Sept 17, l940- F. E. slNcLAlR 2,214,753

FEEDING DEVICE Original Filed Dec. 27, 1935 3 Sheets-Sheet 2 SePt- 17, 1940- F. E. slNcLAlR 2,214,753

FEED'ING DEVICE 3' Shcets-Sheet 5 Original Filed Dec. 27, 1935 9.44 www;

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Patented Sept. 17, 1940 UNITED STATES PATENT orties.

FEEDING DEVICE Frank E2. Sinclair, Claremont, N.

H., assignor to Sullivan Machinery Company, a corporation of Massachusetts 12 Claims.

My invention relates to feeding devices, and more particularly to feeding devices particularly adapted for use with percussive motors which are to be fed in a guided path toward their work.

During the operation of percussive motors, there are set up longitudinal movements thereof, as any one who has held. a runing hammer drill can testify, and it is possible to employ the vibration or jarring of the motor just mentioned to feed the motor either toward. the Work or rearwardly from the work through appropriate apparatus, and it is an object of my invention to provide an improved feeding apparatus for a 'rock drill or other percussive motor operating on this principle. It is another object of my invention to provide an improved vibration or jar operated feeding mechanism in which forward and reverse feed may be accomplished in a very effective manner and in which, moreover, regulated drilling motor movements at Widely varyin-g speeds may be accomplished. It is a further object of my invention to provide an improved controlling mechanism for a vibration-operated feed, and providing for definite and effective regulation of the rate of feed which such a mechanism accomplishes. These and. other advantages and objects of the invention will be apparent in the course lof the following specification and appended claims.

i 30 In the accompanying drawings, in which a preferred embodiment and. two modified forms of construction which my invention may assume in practice have been shown for purposes of illustration,

l is a central longitudinal vertical section through a drilling apparatus in which the preferred embodiment of the invention is incorporated.

Fig. 2 is a plan View on an enlarged scale of the feed controlling apparatus housing.

Fig. 3 is a central vertical section on. approximately the same scale as that of Fig. 2, through the feed controlling apparatus.

Fig. 4 is a transverse section on a still larger scale through Ithe feed controlling apparatus, the section being taken on the plane of the line 4-4 of Fig. 3.

Fig, 5 is a generally similar sectional view .5v with some parts shown in elevation and some parts in a different position.

Fig. 6 is a transverse section on the plane of the line 6 6 of Fig. 3.

Fig. '7 is a similar view with the parts in a ,n.3 different position.

(Cl. Z55-45) Fig. 8 is a View similar to Fig. '7 with the'parts in a still diiferent position.

Fig. 9 is a perspective of a controlling element of the feed controlling apparatus.

Fig. 10 is a perspective of an operating element of the feed controlling apparatus.

Fig. l1 is a perspective of a wear insert.

Fig. 12 is a central vertical section through the feed controlling apparatus of a modified embodiment of my invention.

Fig. 13 is a vertical section on the plane of the line I3-I3 of Fig. l2.

Fig. 14 is a horizontal section on the plane of the line III- I4 of Fig. 12 through the feed controlling apparatus.

Fig. l5 is a vertical transverse section on a smaller scaleI than Fig. 6, but on an approximately similarly located plane, showing a different feed control mechanism.

Referring first to Figs. 1 to l1 inclusive of the drawings and the preferred embodiment of the invention therein disclosed, it may be observed that a motor I, which is herein shown as a hammer rockdrill, has a piston 2 whose striking bar 3 is adapted to actuate percussively a drill steel v 4 which is suitably supported by the drilling motor; and it will further be noted that the drilling motor is arranged for guided longitudinal feeding movements in a shell 5. The drilling motor has a depending feed nut bracket 5 in.w which there is non-rotatably mounted a suitably internally threaded feed nut l. The shell 5 has rearwardly extended rods 8 surrounded by spacl ing sleeves 9 and supporting a housing lil at the rear end of the rods in a well known manner, k

the essential difference from a standard drifter Ashell construction residing in the fact that the feed contro-l housing It) is arranged at the rear end of the rods instead of a mere feed screw support and feed screw rotating handle. A feed screw I I, which may advantageously be provided with a somewhat steeper lead than is customary for ordinary drifting drills of the hand fed type, extends through the feed nut 'I and is rotatably supported at its front end in a support I2 carried by the forward end. of the shell 5. The rearward end of the feed screw Ii is surrounded by a. sleevelike member I3 which is prevented from rotation relative to the feed screw il by a key Ill,'and held against longitudinal movement relative to the feed screw by a nut I5 and lock washer I6. A collar II on the feed screw and another collar I8 on the sleeve I3 cooperate respectively with a front head member I9 and a rear head member 20 of the housing Ii) to pre- Y vent substantial longitudinal movementl of the feed screw relative to the housing I9, and the sleeve is journaled for rotation in a bearing ZI in the forward head member I9 and a bearing 22 in the rearward head member 29. A supplemental housing member 23 surrounds and encloses the collar I8, the nut I5, the washer I6, and the rear end of the feed screw II. The housing I comprises in addition to its front head I9 and rear head 29 a lateral wall-forming member 25 which cooperates with the head members mentioned to provide a chamber 26. This chamber comprises a rearward, generally cylindrical space 2'I and a forward lobelike space 28, the latter space having a series of enlargements or lobelike spaces 29 equi-distantly spaced around the axis of the space 28 and communicating with a smaller central space 39, it being understood that the lobelike spaces 29 and the central space 3B together make up the space 28. The central space 30 is just about large enough to permit the free rotation therein of the sleevelike member I3. The outer walls of the spaces 29 are curved, but their curvature is not that o-f arcs struck on radii equal toi the distance from the center of the space 3B to the central point in each of said outer walls, but instead somewhat flatter in curvature. As a result, each of the three equally spaced spaces 29 has an outer wall 3I which is nearer, adjacent the midpoint thereof, to` the center of the space 30 than at its ends. Within each of the several spaces 29 there are arranged two rollers 32, which may for convenience be termed binding rollers and each of which is of a diameter greater' than the maximum distance between the wall 3E and the most closely adjacent portion of the wall of the sleevelike member I3 which extends through the space 39. Accordingly, as either of the rollers 32 moves toward said Zone of minimum dimension,v there will be a locking of the sleevelike member I3 and a holding of the latter against rotation. On the other hand, either roller, by movement away from the zone of minimum radial dimension, tends to free the sleevelike member i3. Each of the rollers is pressed towards the Zone of minimum dimension of one of the spaces 29 by a spring-pressed follower 33 arranged in a suitable bore 34. In the relatively cylindrical space 27 previously mentioned there is rotatably supported the generally annular fingered member 36, shown in perspective in Fig. 9. It will be observed that this member is provided with three forwardly-extending substantially equally* space`d pin or finger portions 3l, each of these pin or finger portions extending into one of the spaces 29 and each of insuicient width circumferentially of the spaces to be simultaneously contacted by the rollers 32 at the opposite sides thereof. The member 36 is cut away chordally as at 38 and arcuately as at 39. Within the space provided at 39 there is slidably arranged an arcuate member 40, and a` spring @I acts between a shoulder 42 formed on the membei' 3E and the end 43 of member i9 to press the member @i9 towards the wall @Il of the cutaway 33 so that said wall 45, with the wall i5 at the nearer end of the arcuate member 99, provides, in eifect, a slot 45. Within a radially extending bore di' in the member 25, there is rotatably supported the shank portion 58 of an operating handle 49. Said shank portion is provided with a circumferential groove with which a holding pin 5I cooperates to hold the handle member 29 in operative position, and an eccentric lug portion 52 formed on the inner end of the member 58 extends into the slot 36 previously mentioned and is adapted to cooperate with the walls M and i5 of said slot in the manner shortly to be described.

The wall of the member 35 is also cut away arcuately herein, approximately diametrically opposite the location .of the cut-away portion 39, to provide a further arcuate recess 54 having an end wall 55 which is adapted to cooperate with an adjustable limit screw 56 to control the distance which the member 39 can be turned in one direction. The screw 56 is provided with a manually-operable enlarged portion 5i and is mounted in a bushing 58 arranged in a threaded bore 59 in the side wall of the housing member 25. To minimize wear and permit the use of materials especially adapted to long life and freedom from roughening, the outer walls BI of the lobelike spaces 29 are not formed integral with the member 25, but instead the member 25 is provided with three recesses 50 in which hardened inserts 6I, formed of the proper shape and suitably heat-treated, may be disposed.

The mode of operation ofthe apparatus so far described may now be summarized. In the position of the parts shown in Fig. 4, which corresponds to the full-line View of the handle 59 in Fig. 2, the rollers 32 are all pressed by their followers 33 into contact with the periphery of the sleevelike member i3, and of course simul-v taneously, into contact with the respective walls 3l of the several recesses 29. There will, therefore, be no rotation of the sleevelike member possible, as it will be locked against movement in any direction, and, the sleevelike member beingA locked, the feed screw I will also be locked.

If it is desired -to effect a movement of the drill in a direction toward the rear of the shell, the handle 49 may be turned so as to cause the projection 52 to engage the wall 44 of the slot It and rotate the member 36 counterclockwise,

looking forwardly. vThis will cause the fingers 3l to engage the rollers 32 which normally lock the sleevelike member ISagainst rotation clockwise, looking forwardly, and accordingly the sleevelike member i3 can rotate clockwise (look ing forwardly), but not counterclockwise. The tendency of the drill to jump forwardlyvproduces a counterclockwise rotation tendency on the part, `of the feed screw, still speaking of directions,

looking forwardly. That direction of rotation of thefeed screw is prevented with the adjustment of the member 3S which has just been described,

for the three rollers 32 which have not been engaged by the fingers 3l' positively prevent such a direction of rotation of the feed screw. An opposite jumping tendency on the part of the drill can, due to the holding of the other three rollers inactive, cause an actual rotation of the feed screw in a 4clockwise direction, looking forwardly, and such a direction of rotation of the feed screw within the feed nut I causes a retraction of the drilling motor. With the construction shown', this retraction will be quite rapid at'high operating speeds of the drilling motor, and it is not imperative to control the rate of retraction of the drill, though this might be done by providing apparatus similar to that which will now be described for controlling the rate o-f forward feed.

Depending upon the extent to which the ngers 3l are displaced from their so-called central position, there will be different effects on the rollers, and so on the rotative rate of the feed screw.

If the fingers 31 are moved just sufiiciently far to prevent the rollers from rolling inward to their maximum possible extent, but yet not far enough to prevent the rollers from exercising a substantial frictional effect, it will be appreciated that a` feed at a reduced rate will be possible. Such an adjustment of the fingers 31 can be somewhat gradually made manually, but it is extremely difficult to secure the precise effect desired, and even more difficult to maintain it, purely by manual adjustment of the handle 49. For that reason, the mechanismvincluding the arcuate member 40, the spring 4i, the shoulder 55, and the adjustable stop screw 56 is provided; and it will be appreciated that by appropriate adjustment of the stop screw 56 the degree of rotation of the member 35 clockwise, looking forwardly, may be absolutely predetermined, and through the provision of the yieldable arcuate member 48, the handle 49 may be turned to the lower dotted position in Fig. 2 and still not result in a rotation of the member 3B at all similar in extent to the rotative movement provided by a like opposite adjustment of the handle 49. Now let us analyze what happens when'the handle 49 is moved to the lower dotted-line position ofl Fig. 2. It will be noted that this will materially displace the arcuate member 4D in 6 and will place the spring 4l under considerable compression. As a result, this spring acting on the shoulder 42 will rotate the member 3G clockwise just as far as the engagement of the shoulder 55 with the end of the limit screw 56 permits. Accordingly, depending upon the adjustment of the limit screw 56, the set of rollers 32 which control the effecting of forward feed will be more or less rendered inoperative, the more nearly they are rendered inoperative (the less nearly they are permitted to approach their innermost positions) the faster the resultant feed; and the smaller the degree to which they are rendered inoperative the slower the resultant feed. All such feeds effected by partial rendering inoperative of the rollers will be sub-maximum, i. e., less than the feed rate when such rollers are fully inoperative, Obviously, if the screw 55 is adjusted well. toward the right in Fig. 6, an extremely slow feed will result. If the stop screw 55 is adjusted a little further toward the left in Fig. 6, a slightly faster feed will be effected. If it is substantially withdrawn to the left, full speed forward feed may be secured.

From the foregoing description it will be evident that with the device as illustrated a wide range of forward feeding speeds, each quite positively maintained, may be secured, and through manual adjustment and holding of the lever 49 a variable rearward feeding speed can also be accomplished. if that be necessary.

In Figs. l2, 13 and 14 a different device is shown for providing graduated feeding rates. In this form of apparatus the control is equally variable during forward and reverse feed, for the basic principle of operation of this mechanism is a direct retardation of the rotative movements of the feed screw before the rollers are reached in the system.. In other words, the effect is that of braking the rotation of the feed screw and limiting for a given rotative force the degree of turning irrespective of the fact that one or the other sets of rollers may be rendered completely inoperative. This construction differs from the construction described with respect to Figs. l to 11 in two particulars. With it there is no necessity for the arcuate block 40, the adjustable stop screw 5E, etc., so both sides of the apparatus may be made alike in the matter of the manual adjustment. The second particular of difference lies in the fact that a transverse slot is formed in the rear head member 20' and within that slot 5 there is transversely slidable a wedgelike element 64 which is cut away centrally as at 65\.to provide yan opening of a vertical dimension equal approximately to the outside diameter of the sleeve I3, 55 permitting a substantial lateral movement of the wedgelike member 54. The wedgelike member 64 does not taper from .top to bottom, but it does taper from end to end, and its rearward surface B1 lies in a plane perpendicular to the 15 axis of the feed screw, while its forward surface 68 lies in a plane makingy an angle with the axis of the feed screw, and the recess 63 has a forward wall 69 parallel to the surface 58 of the wedgelike member. 10 tends to force the wedgelike member G4 into releasing position, while an adjustable pressure screw 1l acting on the other end of the wedgelike member may be moved to force said wedgelike member inwardly and increase the friction-25 which the same exercises on the forward surface of the collar IB on the sleeve I3.

The mode of operation of this apparatus will now be clear. Let it be assumed that the handle 49 be moved to a position equivalent to either 30 of the dotted line positions shown in Fig. 2. It will be evident then that if the wedgelike member G4 is moved to a position to minimize its frictional engagement with the collar i8 a fast feed in the predetermined direction will result, 35

because the feed screw will be free to turn just l as far as the jump of the drill tends to turn it. When it is desired to reduce the rate of feed, the screw member 1l may be adjusted to force the wedgelike member 54 inwardly to increase.40

the friction between its surface 51 and the front face of the collar i8, and accordingly a given jumping force of the drill motor will not cause so great a rotation of the feed screw because of the resistance to rotation of the feed screw than will be materially built up. By appropriate adjustment of the member 1i and of the wedgelike member 54 a wide range of feeding speeds may be secured. It is of course to be understood that the wedge angle of the member 64 is very smally |50 and that the clearance between the rearward face B1 of said member and the forward surface of the collar I8 is a very small fraction of an inch, even when the wedgelike member 54 is in what may be called its fully released position. `55

Fig. 15 shows another mechanism for controlling the rate of feed. This includes means for holding the member 35 in virtually any position to which it may be adjusted by manipulation of the handle 4Q. The member 36 is cordingly with a similar member 36 which is cut away as at 15 to provide an arcuate surface 16 with which'a brake shoe 11, either resiliently through a spring 18 or positively through the forward end of the screw 19, may be pressed-65 It will be evident that the handle 49 may be adjusted to provide for the desired rate of feed and then held there by tightening up the screw 19 through its manually rotatable head 89. This will positively hold the member 35" in whatever 70 position it may be moved to. By backing off the screw 19 slightly, a more yielding holding of the member 3,6 may be secured7 a holding adequate to position the member in virtually any desired position, but not sumciently positive to prevent and horizontally so as to provide a clearance '10 A spring-actuated plunger 20 replaced ac- 60 the operator, should sudden need for reverse feed arise, from quickly throwing the handle 49 to an opposite position.

It will be observed that I have provided in this application several different arrangements whereby maximum feeding rate and a plurality of definite lesser feeding rates may be effected and maintained. The invention in each of its embodiments is of durable construction, practically proof against accidental derangement, subject to virtually no wear, easy to adjust, and, in two forms at least, capable of permitting immediate reversal of feed, if need arises, with no serious diiiculty despite the provision of arrangement for effecting feed at a reduced rate. By the provision of the inserts previously described, the wear of the device as a whole may be reduced to a minimum and any tendency toward rucking can be absolutely prevented by the employment of specially heat treated materials particularly selected for the conditions involved in this apparatus.

While I have in this application specifically described a preferred form and two modifications in construction which my invention may assume in practice, it will be understood that these are shown for purposes of illustration only, and that the invention may be modified further 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:

l. In combination, a reciprocating-type motor, a guide therefor, said motor wheny running producing alternating tendencies to movement forwardly and rearwardly along said guide, members, of which one is rotatably mounted, respectively carried by the guide and by the motor and mutually interengaged so that movement of the motor along the guide is precluded except upon rotation of said rotatable member, oppositely acting wedging means each normally operative to preclude material rotation of said rotatable member in one direction but controllable to exert no material opposition to rotation of said rotatable member in said direction or to restrict, but not preclude, rotation of said rotatable member in said direction, controlling means for said wedging means movable to determine the regulation which they exercise upon the rotation of said rotatable member, and means including a stop device for limiting controllingmeans movement to a position in which one of said Wedging means restricts but does not preclude rotation of said rotatable member in one direction while the other wedging means substantially wholly precludes opposite rotation of said rotatable member.

2. In combination, a reciprocating-type motor, a guide therefor, said motor when running producing alternating tendencies to movement forwardly and rearwardly along said guide, members, of which one is rotatably mounted, respectively carried by the guide and by the motor and mutually interengaged so that movement of the motor along the guide is precluded except upon rotation of said rotatable member, ieans normally operative to preclude material rotation of said rotatable member in one direction but controllable to exert no material retardation upon the rotation of said rotatable member in said direction or to restrict, but not preclude, rotation of said rotatable member in said direction, means normally operative to preclude material rotation of said rotatable member in the opposite direction but also controllable to exert no material retardation upon rotation of said member in said opposite direction or to restrict, but not preclude, rotation of said rotatable member in said opposite direction, controlling means cooperative with said first and second mentioned means and movable to determine the regulation exercised thereby upon rotation of said rotatable member, and stop means arranged in a position positively to preclude movement of said controlling means in one direction beyond a position in which restricted rotation of said rotatable member in one direction is provided.

3. In combination, a reciprocating-type drilling motor, a guide therefor, said motor when running producing alternating tendencies to movement forwardly and rearwardly along said guide, members, of which one is rotatably mounted, respectively carried by thel guide and by the motor and mutually interengaged so that movement of the motor along the guide is precluded except upon rotation of said rotatable member, means normally operative vto preclude material rotation of said rotatable member in one direction, means normally operative to preclude material rotation of said rotatable member in the opposite direction, and means adjustable to render one of said two means mentioned partially inoperative including abutment means for controlling the degree of its partial inoperativeness.

e. In com-bination, a reciprocating-type drilling motor, a guide therefor, said motor when running producing alternating tendencies to movement forwardly and rearwardly along said guide, members, of which one is rotatably mounted, respectively carried by the guide and by the motor and mutually interengaged so that movement of the motor along the guide is precluded except upon rotation of said, rotatable member, means normally operative to preclude material rotation of said rotatable member in one direction, means normally operative to preclude material rotation of said rotatable member in the opposite direction, and means adjustable to render one of said two means mentioned partially inoperative including adjustable-stop motion-limiting means for controlling the degree of its partial inoperativeness.

5. In combination, a reciprocating-type drilling motor, a guide therefor, said motor when running producing alternating tendencies to movement forwardly and rearwardly along said guide, members, of which one is rotatably mounted, respectively carried by the guide and by the motor and mutually interengaged *so that movement of the motor alongY the guide is precluded except upon rotation of said rotatable member, means normally operative to preclude material rotation of said rotatable member in one direction, means normally operative to preclude material rotation of said rotatable member in the opposite direction, and means for positively moving one of said means into a partially operative position and for yieldingly moving the other into a partially operative position including a yieldable operating connection and a device for positively limiting the movement imparted by said yieldable connection.

6. In a feeding device, in combination, a motor and a support on which said motor is slidably mounted, said motor having a recipro- Vcatory hammer piston whose reversals ofY motion tend to move the motor. longitudinally of the support, means for restraining such movement operatively connected to the motor and the support and comprising a pair/of members in threaded engagement with each other andfone of which members is adapted'to be rotated by the other member upon movement of said motor on the support, stop means forr selectively controlling the direction of rotationof the rotatable member to enable the motor to be advanced and retracted with respect to thesupport by the piston, and wedge means including a wedge movable bodily transversely of said rotatable member and a coacting surface'perpendicular to the axis of rotation of said rotatable member and turning with the latter for retarding the rate of rotation of said rotatable member.

7. In a feeding device, in combination, a motor and a support on which said motor is slidably mounted, said motor having a reciprocatory hammer piston whose reversals of motion tend to move the motor longitudinally of the support, means for restraining such movement operatively connected to the motor and the support and comprising a pair of members in threaded engagement with each other and one of which members is adapted to be rotated by the other upon movement of 4said motor on the support, stop means for selectively controlling the direction of rotation of the rotatable member to enable the motor to be advanced and retracted with respect to the support by the piston, and controlling means for said stop means having means, including devices for stopping movement effected thereby in predetermined positions, for enabling predetermined positioning thereof for sub-maximum feeds.

8. In combination, a reciprocating-type drilling motor, a guide therefor, said motor when running producing alternating tendencies to movement forwardly and rearwardly along said guide, members, of which one is rotatably mounted, respectively carried by the guide and by the motor and mutually interengaged so that movement of the motor along the guide is precluded except upon rotation of said rotatable member, means normally operative to preclude material rotation of said rotatable member in one direction including frictional binding means and means for pressing the same resiliently into a position substantially precluding rotation of said rotatable member in said direction, means normally operative to preclude material rotation of said rotatable member in the opposite directionv including frictional binding means and means for pressing the same resiliently into a position precluding substantial rotation of said member in said opposite direction, a member adjustable oppositely from a predetermined intermediate position to control said different frictional binding means, and adjustable-stop means for limiting the movement of said last mentioned member in one direction to a position in which it renders one of said frictional binding means only partially inoperative.

9. In combination, a reciprocating-type drilling motor, a guide therefor, said motor when running producing alternating tendencies to movement forwardly and rearwardly along said guide, members, of which one is rotatably mounted, respectively carried by the guide and by the motor and mutually interengaged so that movement of the motor along the guide is precluded except upon rotation of said rotatable member, means normally operative to preclude material rotation ofl said rotatable member in one direction, means normally operative to preclude material rotation of said rotatable member in the opposite direction, means variably adjustable'to render one of said two means ineffective to differentdegrees, and detent means for automatically maintaining said adjustable means in its various adjusted positions.

. 10.'In combination, a reciprocating-type drilling motor, a guide therefor, said motor when u running producing alternating tendencies to movement forwardly and rearwardly along said guide, members, ofl which one is rotatably mounted, respectively carried by the guide and by the motor and mutually interengaged so that movement of the motor along the guide is precluded except upon rotation of said rotatable member, means normally operative to preclude material rotation of said rotatable member in one direction, means normally operative to preclude material rotation of said rotatable mem,- ber in the opposite direction, means adjustable to control the action of said rotation-precluding means, and controlling means for said adjustable means movable to .opposite extreme positions respectively to cause said adjustable means positively to render one of said rotation-precluding means completely inoperative and to move said adjustable means yieldingly to a point to render the other rotaton-precluding means partially inoperative, said adjustable means having a stop associated with it to limit its movement in the last mentioned direction to the point specified. l

11. In combination, a reciprocating-type drilling motor, a guide therefor, said motor when running producing alternating tendencies to movement forwardly and rearwardly along said guide, members, of which one is rotatably mounted, respectively carried by the guide and by the motor and mutually interengaged so that movement of the motor along the guide is precluded except upon rotation of said rotatable member, means normally operative to preclude material rotation of said rotatable member in one direction, means normally operative to preclude material rotation of said rotatable member in the opposite direction, means oppositely movable directly to control the functioning of said different rotation-precluding means, and controlling means for said last-mentioned means adjustable in one direction positively to move the latter in one direction to effect complete ineiectiveness of one of said rotation-precluding means and having a yieldable thrust-transmitting connection associated therewith through which upon adjustment in the opposite direction it moves said oppositely movable controlling means yieldingly in the opposite direction to render the other of said rotation-precluding means partially ineffective, said oppositely movable means having associated therewith an adjustable abutment to limit its movement under the yielding thrust transmitted thereto.

12. In combination, a reciprocating-type drilling motor, a guide therefor, said motor when running producing alternating tendencies to movement forwardly and rearwardly along said guide, members, of which one is rotatably mounted, respectively carried by the guide and by the motor and mutually interengaged so that movement of the motor along the guide is precluded except upon rotation of said rotatable member, means normally operative to preclude material rotation of said rotatable member in 'one direction including frictional binding means and means for pressing the s ame resilientlyinto a position substantially precluding rotation of said rotatable member in said direction, means normally operative to preclude material rotation of said rotatable member in the opposite direction including. frictional binding means and means for pressing the same resiliently into a position precluding substantial rotation ofsaid rotatable member in said opposite directiton, a controlling element having like ranges of operating movements in opposite directions from a pre; determined neutral position, and means actuated thereby on its extreme movement in one direction to render one of said frictional binding means fully operative and the other fully inoperative and on its equal opposite operating movement from said neutral position to render said first mentioned frictional binding means partially but not fully operative and the other fully operative.

FRANK E. SINCLAIR.

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