US2316192A - Feeding mechanism - Google Patents

Description

April 13, 1943. F. E ,s`lNcLAlR FEEDING MECHANISM Filed July 16, 1940 Patented Apr. 13, 1943 UNTTED STATES PATENT OFFICE 2,316,192 1 FEEDING MECHANESM Frank E. Sinclair, Claremont, N. H., assigner to Sullivan Machinery Company, a corporation of Massachusetts Application July 1e, 1940, serial No. 345,795 140mm. (C1. 25e-45) My invention relates to feeding mechanisms, and more particularly but not exclusively to feeding mechanisms for rock drills of the socalled air-feed drifter type.

vIn rock drills ofthe so-called air-feed drifter type, rock drilling motors are commonly slida'blt7 guided for reciprocatory feeding and retracting -movements along guide shells or their equivalents, and are provided with means actuated by air motors for effecting such opposite movements.

Power for feeding and retraction may =be derived either from the drilling motor or a separate mo- Y tor. A very satisfactory mechanism for. effecting such movements comprises a longitudinally fixed feed screw rotatable in opposite directions at the'steel, having set the feed motor` in reversel rotation, beV distracted or turn their attention elsewhere, with the result that the feednut may be moved to the rearward limit of possible motion and the parts may become jammed, this being easily possible because the load during re-` traction is usually small and the power of the Vfeed may be considerable, so that when the rearward limit of feed is reached `a wedging action takes place between the rotating and the stationary parts, with the resultant bother and nuisance of having to free the parts. Moreover,

`it is not impossible that some damage may be occasioned by the sudden `stoppage of the parts which have been previously in relatively free movement. It will be appreciated that similar difficulties may also at times be encountered at the forward limit of feed, and that Vwith automatic jump feeds, and even with manual feeds,

(analogous, though less serious, difficulties may be met. Y i

Ina preferred embodiment of my invention it .may include relatively rotatable feeding elements, a source of power for turning one of said elements, thereby to cause a feeding or retract- 'ging movement of one of said elementaimeans for building up a load progressively as a member of such means is moved, and means for causying the movement of the feeding element last mentioned to effect, automatically, when a limit of feed is approached, a connection whereby said power-turned element effects a load-increasing movementof said member. Desirably, but not necessarily, the `source of power may be separate from the work-performing motor when a workperforming motor is the device to be fed. In some cases the hammer motor itself may constitute the source of power; and the feed may be effected by jumping action of the hammer `motor, or by power drive of the rotatable feeding element through a suitable driving lmechanism. Even manual rotation ofthe screw is included within the purview of the invention. Desirably, but not necessarily, a torsion spring coupleable for winding up by the power-turned `feeding element may beutilized as the source of increasing resistance to the turning of said power-turned element. Other aspects and phases of the invention will hereinafter appear.

It is an object of my' present inventionto provide `an improved means for avoiding the difficulty mentioned. It is another object of my invention -to provide an improved feeding mechanism fora rock drilling motor.v It is a further object 'of my invention to provide an' improved `means for bringing to a stop, without harmful V'sliock,and withoutV sticking or'jamming of the parts, the moving hammer motor of a power-fed drifter, in the event that` the operator fails to turn off at a seasonable time the motorwhich is effecting feeding movement. It is another object of my invention to provide an improved .means for automatically checking feeding movement at either end of the travel'of a drifter drill, regardless of the type of feed used, before sticking occurs. It isrstill another object of my invention to provide an improved feeding mechanism for an air-feed hammer motor or other working tool, having improved means incorporl ated therein for storing `energy to facilitatethe initiation of a reversal of a feeding movement, while at theA same time automatically interrupting,.without damage or sticking, a feeding movement which is not seasonably stopped `by the drill runner." Yet another object of my invention is to provide an improved feed-checking apparatus of general application to any motor-operated or other comparable-problem-presenting feeding mechanism for moving a part to fbe fedgrelative' to a fixed limit. Other objectsand 'advantages of the invention will hereinafter more fully appear. ,Y

In the accompanying drawing, in which for purposes of illustration one embodiment of the invention is disclosed:` I

Fig. 1 is aside. elevation,

with lparts broken away, of a so-called air-feed drifter in which the invention in its illustrative form is incorporated. Fig. 2 is a somewhat enlarged view, with parts shown in elevation but mainly in central vertical longitudinal section, through the feeding mechanism of the apparatus shown in Fig. 1.

Fig. 3 is a view generally similar to Fig. 2 but omitting some of the parts shown in Fig. 2, and with some of the parts which appear in both figures in different relative positions in Fig. 3 from those of Fig. 2.

Fig. 4 is a transverse section on a somewhat enlarged scale on the plane of the line 4*--4 of Fig, 2.

Fig. 5 is a transverse section on a somewhat enlarged scale on the plane of the line Ve-Ei of Fig. 2.

Fig. 6 is a transverse section on a somewhat l enlarged scale on the plane of the line S- of Fig. 2.

Fig. 'l is a section on the plane of the line l-l of Fig. 4, through a clutch element. I

Referring now to the drawing, it will be noted that a hammer motor I, which is adapted percussively to a-ctuate a drill steel 2, is mounted for sliding movement in a guide shell 3. The motor I has a depending lug 4 at its rear end in which a feed nut 5 is received, said feed nut being vclamped in position by means of a washer 6 and a holding nut 'I at the rearward end of the lug 4, and the feed nut having, at its forward end, a head 8 spaced by another washer 9 from the lug 4, The feed nut is adapted to cooperate with a feed screw II. The feed screw II is provided, at its rear end, with an enlarged circertain of the cylinders being shown at 2), 2li, 2B.

The motor I'I .is reversible, and a'handle 2l is movable, herein arcuately, between opposite eX- treme positions in which forward feed and retraction are respectively effected, the feeding motor being shutv down completely in an intermediate position of the handle 2|. A motor1 power shaft is shown at 22, and this is connected l through a suitable tongue and slot connection 23 to drive the rear end of the feed screw It. The forward end of the feed screw may be journaled in any suitable way, as at 2li, at or adjacent the forward end of the shell 3. The feed screw is of course held against longitudinal movement relative to the shell 3, and accordingly its rotation in one direction will cause the feed nut 5, which is fixed non-rotatably in the lug Ii, to move longitudinally of the guideways of the shell 3 and so effect movement of the hammer motor I in one direction.l Movement of the hammer motor in the opposite direction will, of course, be occasioned by the reverse rotation of the feed screw II Now, if the drill runner moves the handle 2l to a position to effect forward feed and supplies air under the control of a throttle valve mechanism 25 to the hammer motor I, the drill steel 2 may be caused to drill a hole. Because during the drilling operation the operator will be giving the apparatus close supervision, and because the rate of forward feed is comparatively slow, and vbeof the parts.

member d I'.

asiatica cause Vthe operator will be continuously on the Watch for the point where steel change is to be effected when reached, there is little prospect of jamming the feed during the forward feeding operation. When, however, the desired limit of forward feed has been reached and the drill is being retracted, the feeding movement will be much more rapid, and frequent sticking of the parts and undesirable shocks due to the motors feeding back to the rearward limit of its feed, would occur were no means for guarding against this difficulty provided. I have provided, to avoid this diculty, a mechanism adapted to build up an increasing resistance to rotation of the feed screw as the hammer motor approaches the rearward limit of its travel; a mechanism which will store energy while bringing the feed screw to a stop, which energy will be available to initiate the opposite movement ofthe feed screw, and which mechanism is desirably, though this is not necessary in View of the energy-storing feature, adapted to preclude al frictional locking At this point it should be noted that there is no reason why similar mechanism may not be provided at the front end of the shell if desired.. Itwill be noted that the locking nut "I is provided with a somewhat elongated rearward cylindrical portion 35 which is of a size to enter an opening 3-I in a threaded sleeve member 32, which is screwed into an internally threaded projecting portion 32 on the forward member 35 of the housing I. The opening 3| is of somewhat smaller diameter than the internal cylindrical bore 31 which is formed within the member 32. Within the bore. 31 and between the inwardly turned flange 33 which surrounds the opening, 3| and a shoulder 39 formed by an inwardly extending flange on the head member 35, there are arranged a stop element in the form of a clutch member 4I and a helical spring 42 of the torsion type. The rearward Yend of the spring 42 has a tang 43 which is received in a recess. i4 formed in the flange 39. The forward end of the spring has a tang received in a recess or notch 5I in the clutch The clutch member' il is cut away, as at 52, so as to permit it to be' positioned, when the housing member* 32 is unscrewed from its mounting, over the feed screw member II in the proper position,

The portion of the feed screw member I I within the bore 3l is provided with a series of longitudinally extending tooth-like portions 54 whose forward ends are slanted, as at 55, somewhat more steeply than the lead of the feed screw. The clutch member Il is provided with corre'- sponding tooth or spline-like portions 56, having sloping rearward ends 51. YIn the position of the parts Vnormally occupied, that shown in Fig. 2, the teeth 54 and 56 are disengaged. In the position shown in Fig. 3 they are engaged and all rotation of the feed screw is attended by rotation of the clutch member 4I.

The spring l2 may be made of different strengths, but I prefer to make it of such dimensions and strength that the amount of power required to wind it up will be such that the feeding motor will be brought to a stop by the increased load before the spring is fully wound up into contact with the outside of the teeth 54, and before the spring is compressed longitudinally sufficiently to bring its successive turns into lateral engagement. And the length ofl the portion 32 will be made suflicient so that there I pended claims..

will be no engagement between the member 32 and tne nut l before the motor 'is stopped.

-also be true during thenormal range of retraction. But if the operator fails to stop the feeding motor seasonably and the hammer motor tends to move so far back that there would be danger of jamming the parts, the projection 3D will enter the opening 3| and engage the `clutch member 4|.

As the clutch member, 4| is forced to the left in Figs. 2 and 3, its slopingtended teeth 5B will .engage with Vthe teeth-54 on the feed screw member and slide rearwardly between the latter teeth. As soon as such engagement occurs, the clutch member 4| will The only parts between which substantial frictional binding may occur will be between the rear end of the feed nut and the holding nut 30, on the one hand,v and the clutch member 4|, but this will be easily overcome by the stored energy in the spring 42, and if desired an antifriction bearing can be provided to transmit the thrust from the feed nut to the clutch member 4| and so eliminate even the binding mentioned.

It will be evident from what has been said that I have provided a device which will effectively prevent breakage and jamming of the parts if the retraction is not seasonablyinterrupted by the' drill runner; that the parts are simple and Yrugged and require very little` modification from During `forward feed- 2- respectively, said elements in engagement with each other and operative on relative rotation to effect movement of `said tool along said guiding and supporting means, a motorfor rotating one of said elements, and means for automatically imposing on said motor an additional load suf- -cientto stop tool movement as said tool approaches an end of its travel on said guiding and supporting means, said load-imposing means including a stop elementv rotatable about an #axis and with which an element of said workperforming tool is engageable and resilient means forY resisting rotary` movement of said stop element. l

l2. In combination, a Work-performing tool, guiding and supporting means therefor along which said tool is adapted to be fed during feeding towards and retraction from the work, relatively rotatable elements mounted on said tool and on said guiding and supporting means respectively, said elements in engagement with each other and operative on relative rotation to effect movement of said tool along said guidstandard parts which lack the advantages of the present invention; and that if the `refinement available to prevent any frictional binding whatever is not considered warranted,`for any reason, the energy stored in the spring will be in any event more than adequate toinsure immediate initiation of forward feed when the lever'2l is moved to forward feed position. It is to be observed also, as above pointed out, that the use of such a device is not limited to the `type of feed shown, or to the rearward end of the feed screw. l Y Y While I have in this application specifically' described one form which my invention may ,assume in practice, it will be understood that this form is shown for purposes of illustration and that the invention may be modied and iembodied in various other forms without departing from its spirit or the scope of the ap- What I claim as new and desire to secure by Letters Patent is:

1. In combination, a work-performing tool,

, guiding and supporting means therefor along `which said tool is adapted to be fed during feedandmon lsaidnguiding and supporting-means,

ing and supporting means, a motor for rotating one of said elements, and means for automatically imposing on said motor an additional load, increasing as tool movement continues, as said tool approaches an end of its travel on said guiding and supporting means, said load-imposing means including a stop element having limited rotary motion and actuated by an element of said work-performing tool and resilient means for resisting rotary motion of said stop element.

3. Incombination, a Work-performing tool, guiding and supporting meansfor said tool, motor-operated feeding means for said tool including a motor-rotated element and an element with which said motor-rotated element is engaged,

saidelements so disposed and engaged in such manner that rotation of said motor-rotated element causes movement, longitudinally of said,

guiding and supporting means, of one of said elements, said work-,performing tool having said last mentioned element connected thereto so,` that such longitudinal movements of said element are attended by movements of said tool longitudinally of .said guiding and supporting means, and means for precluding overtravel of said tool fin one direction including a spring coaxial with saidmotor-rotated element and means for increasing the tension in said spring as the limit of travel in such direction is approached, said spring tension increasing means including a rotary stop element which is engageable by an element of said Work-performing tool.

4. In combination, a work-performing tool, "guiding and supporting means for said tool, mo-

nected thereto so that such longitudinal movements of said element are attended by movements of said tool longitudinally of said guiding and supporting means, and means for precluding overtravel of said tool in onevdirection Aincluding a spring` fixed at one end and means for moving the other end of said spring in a direction to increase the tension thereof as the limit of -travel insuch direction Vis approached,

said spring tension increasing means including a stop element engageable by an element of said work-performing tool and having limited rotary motion, said spring opposing the rotary motion of said stop element.

5. In combination, a work-performing motor, a. guidewjay along which saidv motor is reciprocabie towards and from its Work, a feed 'screw extending longitudinally of .said guideway, a feed nut carried by said work-performing motor, motor-operated driving means for said feed screw, a torsion spring surrounding said feed screw and 4having one `end thereof fixed, an element relative to which said feed scr'evvis normally rotatable and which is movable longitudinally of said feed screw and to whichthe other end of said spring is fixed, means operative on movement of saidelement longitudinally of said screw inrone direction for effecting clutching of said element to said screw,y whereby subsequent rotation of said screw Will effect Winding up of said spring, and means movable with said motor for effecting movement of said element into clutched engagement with said screw.

- 5. In combination, a work-performing motor, a guideway along which said motor is reciprocable towards and from its work, a feed screw extending longitudinally of said guideway, a feed nut carried by said work-performing motor, motor-operated driving' means for said feed screw, a torsion spring surrounding' said feed screw and having one `end thereof fixed, an element relative to which said .feed screw is Ynormally rctatableand which is movable longitutinally of said feed screw and to which the other end of said'spring is fixed, means including clutch teeth on said screw and cooperating clutch teeth on said element operative on movement of said element longitudinally of said screw in one direction for effecting clutching of said Velement to said screw, whereby subsequent rotation of said screw will effect winding up of said spring, and means movable with said motor for eecting movement of said element into clutched engagement with said screw.

'7.In combination, in a feeding mechanism, a feed screw, a feed nut, motor-operated means for turning said feed screw in opposite directions at wiil,and means actuated automatically on movement of said feed nut past a predetermined point in one direction for imposing on said feed screw a resistance to rotation progressively increasing as such movement of said feed nut continues, said resistance-imposing means including stop means having limited rotary motion and resilient resistance means for priogressively increasing the resistance to rotary motion. of said stop means as said feed nut passes said predetermined point.

8. In combination, in a feeding mechanism, a feed screw, a feed nut, means for turning said feed screw, and means actuated automatically on movement of said feed nut into a predetermined relation to an end of said feed screw for imposing on said feed screw an increasing resistance to rotation, while the feed nut is still free to move, until the resistance to screw rotation exceeds the torque on the screw, said resistance-imposing means embodying stop means having limited rotary motion and resilient means for increasingly opposing rotary motion of said stop means as said feed nut moves into said predetermined relation.

9. In combination, a work-performing tool, guiding and supporting means therefor along which said tool is adapted to be fed during feeding towards and retraction .from the work, relatively rotatable elements mounted on said tool and on said guiding and supporting means respectively, said elements in engagement with each other and operative on relative rotation to effect movement of said tool along said guiding and supporting means, a motor for. rotating one of said elements, and means for automatically imposing on said motor an additional load as said tool approaches an end of its travel on said guiding and supporting means, said load-imposing means including a torsion spring and cooperating means actuated by said motor-rotated element for winding up saidrspring as said ytool approaches Vsaid end of lits travel;

l0. In combination, a work-performing tool, guiding and supporting means 'therefor along which said tool is adapted to be fed during feeding towards and retraction from the work, relatively rotatable elements mounted on said tool and on said guiding .and supporting means respectively, said elements in engagement with each other and operative on relative rotation to .eect movement of said tool along said guiding and supporting means, a motor for rotating one of said elements, and means for automatically imposing on said motor an additional load as said tool approaches anend of its travel on said guiding'and supporting means, said load-imposing means including a tors-ion spring adapted to be wound up and cooperating spring-Winding means and means governed by tool movement for effecting actuation of said spring-winding means by said motor-rotated element to effect Winding up of said spring as said tool approaches said end of its travel.

11. In combination, a work-performing tool, guiding and supporting means for said tool, motor-operated feeding means for said tool including a motor-rotated element and an element with which said motor-rotated element is engaged, said elements so disposed and engaged in such manner that rotation of said motor-rotated elementV causes movement, longitudinally of said guiding and supporting means, of one of said elements, said work-performing tool having said last mentioned element connected thereto so that such longitudinal movement of said element is attended by movement of said tool longitudinally of said guiding and supporting means, and means Y for limiting travel of said tool in one direction including a torsion spring coaxial with said m0- tor-rotated element and cooperating springwinding means actuated by said motor-rotated element for winding up said spring as'said limit of travel is approached.

12. In combination, a Work-performing tool, guiding and supporting means for said tool, motor-operated feeding means for said tool including a motor-rotated element and an element with which said motor-rotated element is -engaged, said elements so disposed and engaged in such manner that rotation of said motor-rotated element causes movement, longitudinally of said guiding and supporting means, of one of said elements, said Work-performing tool having said last mentioned element connected thereto so that such longitudinal movement of said element is attended by movement ofV said tool longitudinally of said guiding and supporting means, and means for limiting travel of said tool in one direction including a torsion spring and cooperating springwinding means actuated by said motor-rotated element for Winding up said spring to increase the torsion of said spring automatically as said limit of travel is approached.

13. In combination, a Work-performing tool, guiding and supporting means therefor along which said tool is adapted to be fed during feeding towards and retraction from the Work, relatively rotatable elements mounted on said tooi and on said guiding and supporting means respectively, said elements in engagement With each other and operative on relative rotation to effect movement of said tool along said guiding and supporting means, a motor for rotating one of said elements, and means for automatically imposing on said motor an additional load suicient to stop tool movement as said tool approaches an end of its travel on said guiding and supporting means, said load-imposing means embodying rotary resistance means including rotary means actuated by said motor-rotated element, said rotary resistance means providing increasing torsional resistance as said tool approaches its position wherein it is stopped by said load-imposing means, said rotary means being rotated by said motor-rotated element as said tool approaches said position thereby to increase the resistance to tool movement.

14. In combination, a Work-performing tool, guiding and supporting means therefor along .which said tool is adapted to be fed during feeding towards and retraction from the Work, rela'- tively rotatable elements mounted on said tool and on said guiding and supporting means respectively, said elements in engagement with each other and operative on relative rotation to effect movement of said tool along said guiding and supporting means, a motor for rotating one of said elements, and means for automatically imposing on said motor an additional load suicient to stop tool movement as said tool approaches an end of its travel on said guiding and supporting means, said load-imposing means embodying rotary resistance means including means subjected to both torsion and axial compression and .cooperating rotary and axially movable means actuated for the application of torsional forces by said motor-rotated element for applying torsional and compression forces to said torsion and compression-subjected means and the latter providing under each force increased resistance as said tool approaches its position wherein it is stopped by said load-imposing means, said rotary and axially movable means being actuated by said motor-rotated element as said tool approaches said position.

FRAN K E. SINCLAIR.

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