US2458929A

US2458929A - Chip breaking mechanism for metal drilling and like machines

Info

Publication number: US2458929A
Application number: US515942A
Authority: US
Inventors: Carleton B Clark
Original assignee: KINGSBURY MACHINE TOOL CORP
Current assignee: KINGSBURY MACHINE TOOL CORP
Priority date: 1943-12-28
Filing date: 1943-12-28
Publication date: 1949-01-11
Anticipated expiration: 1966-01-11

Description

Jan. 11, 1949. c. B. CLARK 2,458,929

CHIP BREAKING MECHANISM FOR METAL DRILLING AND LIKE MACHINES Filed Dec. 28, 1945 Patented Jan. 11, 1949 CHIP BREAKING MECHANISM FOR METAL DRILLING AND LIKE MACHINES Carleton B. Clark, Keene, N. H., assignor to Kingsbury Machine Tool Corporation, Keene, N. H., a corporation of New Hampshire Application December 28, 1943, Serial No. 515,942

10 Claims. 1

This invention relates to a chip breaking mechanism for employment in metal drilling and like machines and is more particularly concerned with the control of the feeding movement of a drill or like metal working device, whereby the tool is caused to perform a progressive, oscillatory movement during the course of its rotation, wherewith the path of the cutting portion of the tool departs from a uniform helix.

When employed in a metal drilling machine, this departure of the cutting edge of the tool from a condition of tracing a uniform helix permits the removal of the metal in the forming of a series of small chips so that the same can be removed from the cutting face along the flutes of the drill without difficulty of clogging or impeding the free movement of the tool while doing its work.

The feeding mechanism of such a drilling machine, in accordance with the present invention, comprises the structures effective for producing an axial oscillation between the drill spindle and its support during the course of rotation of the spindle; so that when this axial oscillation is superimposed upon the feeding motion of the support itself, a withdrawal movement is produced which is preferably at least equal to the forward feeding by the primary feeding. means acting upon the spindle support, whereby the cutting edge of the drill bit is caused to pass through the surface of the metal being cut and thus produce successively a series of separate chips.

In the practice of the invention, this axial oscillation is obtained by providing a member which rotates about an axis positioned at an angle with respect to the spindle axis, so thatthe distance between a radial plane of the spindle and a radial plane of this tilted axis varies from point to point during the course of revolution of the spindle, wherewith a spindle collar is provided so that a point in its periphery is maintained at a constant distance from the fixed radial plane through the tilted axis and this collar then moves axially with respect to a fixed plane through the support axis.

Another feature of the invention is the provision of means for obtaining and maintaining a desired angle of tilt, whereby to determine the extent of the axial oscillations.

In the accompanying drawing is illustrated one form of practicing the invention in which Figure l is a perspective view of a metal drilling machine having the present invention therein.-

Figure 2 is an upright sectional view through the spindle and quill assembly of the illustrative metal drilling machine.

Figures 3 and 4 are respectively sectional w'ews substantially on lines 3-3 and 4- -4 of Figure 2.

Figure 5 is a perspective view of the adjustin bushing and spacer piece, separated from one another to show their abutting surfaces.

Figure 6 is an unfolded view representing the paths of successive movements of the two lips of an ordinary metal drill bit through three revolutions of the spindle.

In these drawings, Figure 1 shows a conventionalized metal drilling machine having a stand or upright support ID with a drill table H thereon. The top bracket l2 provides a housing 13 in which the quill l4 maybe reciprocated upon rotation of a quill feeding means conventionally shown as including a gear l5 mounted on a. shaft Hi, this gear l5 being driven by a gear l1 which receives power (by means not shown) for producing a downward feeding motion of the quill l4, and usually producing a retraction thereof automatically at the completion of a drilling operation. Within the quill I4 is a drill spindle l8 which is illustrated as driven by a pulley l9 and a driving belt '20. At the lower end of the drill spindle is a chuck 2| for receiving a drill bit 22 which is illustrated as being of the usual twofluted spiral type, with two drilling lips.

As shown in Figure 2, the shaft l6 supports, within the housing l3, a quill gear 25, which engages with the rack teeth 26 on the quill I l.

The lower end of the quill I4 is provided with a housing 30 whose inner wall is substantially cylindrical in the illustratedform. An annular thrust member 3| is located within the housin 30 and has a spherical surface for its downwardly directed face. An outer sleeve 32 has its upper end provided with a spherical surface engaged with the corresponding surface of the thrust member 3!. This outer sleeve 32 receives the outer race 33 of an anti-friction bearing having the balls34 and an inner race 35. An inner sleeve 36 has a radial projecting flange at its lower end for engaging the lower end of the inner race 35, and has a threaded portion, 31 at its upper end to receive a clamping nut 38 which engagesthe upper. end of the inner race 35. Nut locking means 38 are preferably included for holding'the assembly together.

A retaining nut M1 is threadedly engaged with the lower end of the housing 30 and has an inwardly extending flange for engaging the adjust- .ment bushing 4i which can be rotated within the housing 30. The lower end of the bushing 4| projects from the nut 45 so that it may be engaged and rotated about the axis of the spindle IS. The upper end of the bushing 4| has a surface 42 which is inclined with regard to the radial planes through the spindle axis (Fig. 5).

An annular spacer piece 45 bears at its upper end against the lower edge of the outer sleeve 32, these mating surfaces lying in a plane. The

lower surface of the spacer piece 45 is at an angle to its upper surface so that the spacer piece is essentially wedge-shaped (Fig. 5). surface bears against the upper surface 42 of the bushing 4|. A radial notch 46 of limited peripheral dimension is engaged by a pin ll; secured in the housing 30, wherewith the spacer piece 45' is prevented from rotation with. respect to the housing 30.

An internal shoulder 48 of the bushing 4| forms an abutment for a resilient structure comprised of two dished spring washers 49-, this resilient structure bearing at its upper end against the lower edge of an outer race 58 of the antifriction bearing which has the balls 5| and the inner race 52. The upper edge of the inner race 52 bears against a collar 53 fixed on the spindle I8.

A thrust transmitting member illustrated as a ball 55'bears against thecollar 53 at a point offset from the axis of the spindle, and also .bears against the lower surface of theinner sleeve 35. As illustrated, it is preferred to provide a depression 56 in the surface of the inner sleeve 36, and an edge notch ST in the collar 53 for receiving this ball 55. The ball 55 thus acts to transmit thrust in a direction parallel to. the axis of the spindle l8' and: also serves to deliver tangential force from the collar 53- to the inner sleeve 35' whereby to produce the rotation of the latter.

Bydesign of structure, the spherical surfaces of the thrust member 31' and of the outer sleeve 32 have their common center 69 on the axis of the spindle l8; and a radial plane of the axis of the inner sleeve 36 includes this center 59 and also the center of the ball 55. By this arrangement, the tilting of the axis of the inner sleeve 36 has no influence upon the path of movement of the ball 55 relative to the radial planes of the sleeve 35, but asthe angle of tilt becomes greater the distance between fixed radial planes of the spindle and of this tilted axis will" vary, being least at one point and greatest at a diametrically opposite point, along the common axial plane containing both axes.

The bushing M is preferably formed with an annular hollow boxing 10- which is frictionally fittedv in thebushing and supports a packing gasket H for sealing the interior of the housing.

In operation, while the spindle I8 is rotating about itsaxis, the ball-5.51s carried therewith and servesas a driving element for causing. the inner. sleeve35 to rotate within its anti-friction bearing 3335. Upward thrusts along. the. spindle, such. asare produced by reaction from thetool engagement with the work, aretransmittedfrom the col-- lar 53. through the ball 55, sleeve 35, the anti friction bearing, to the outer sleeve 32 and thence at the spherical surfacesto the thrust member 3! and thence to the quill l4.

During the rotation of the inner sleeve 36, however, if the axis of the inner sleeve 35 does not coincide with or lie parallel to the axis of the spindlelil, the ball 55 does notmove solely in a plane which is radial to the axis of the spindle l8 and which is fixed relative to-the quill M, with advancement of this radial plane as the q ll This lower is fed downward by the quill gear 25; but during each revolution of the spindle, and assuming no axial movement of the quill, the ball travels in a circular path in a plane at right angles to the axis of the sleeve 36: when the sleeve axis is, as shown, at an angle to the spindle axis, the ball is caused to move relatively upward as it passes from the right hand position shown by a full line into the left hand position shown by a dotted line, under the urgency of the resilient structure 49, and then down again. This upward and downward movement is occasioned by the angular position of the sleeve 35 relative to the spindle axis, as the depression is closer to the lower end of the housing 30 at the full-line position of the ball 55 than when it is in the dotted line position. Therefore, during the revolution of the spindle, the collar 53..performs upward and downward movements, under the action of the resilient structure 49 and under the pressure exerted from the rotating inner sleeve 55 through the ball 55. In the position of parts shown by full-lines in Figure 2, the ball 55 Eat the lowest or most forward point in its translation with the periphery of the inclinable sleeve 35 and hence it is now acting as a thrust-transmitting member to hold the spindle collar 53 at the lowest position, being that in which the ball 55 and the collar 53 are closest to the end packing As the spindle turns, owing to the inclined axis of rotation of the sleeve 35, its depression or recess 56 moves relatively upwardly in the drawing, or away from the end packing 75, together with the ball 55, under the action of springs 49 in this illustrated form, until after degrees of movement of the spindle, the ball 55 reaches its greatest distance from this packing and therewith the collar 53 has retreated to its greatest distance from the end packing H. Thereafter, the continued rotation of the spindle brings the .ball 55 back again into the position shown in the drawing, by its motion of transla tion with the spindle and by its axial downward movement produced by thrust delivered by the sleeve 35'.- Thus, the ball 55, the collar 53, the spindle and one lip of a two-lipped drill perform a movement as illustrated by the line 8| in Fig-- ure 6; this movement being a composite one consisting of a feeding motion of the quill and of an axial component of cyclic reciprocation of the ball 55. correspondingly, the other lip performs an identical movement but at the diametrically opposite part of the hole, that is, 180 degrees away, as shown by the line 82 in Fig. 6.

Therefore, in addition to the assumed uniform downward feed ofthe quill through the quill feed gear 25, thereis also an axial oscillation which results in a successive gouging motion on the part of thedrill bit lips, whereby independent chips are removed from the metal to be drilled.

The path of movement of the two drill lips is represented in Figure 6 for the course of three revolutions. Assuming that the upper line 88 of this figure "represents the top surface of the piece of work W; the combined effects of the uniform feed from the gear l1 and of the axial oscillatory feed of the structure shown in Figure 2 causes one of the drill lips to trace a curve 8| with successive upward and downward stroke effects while having a constant increment of general downward movement. This graph or curve 8| is shown in full lines in Figure 6 through three successive revolutions. the drilling operation, this first drill lip will follow the curve 8| in the portion of Figure 6 representing the first revolution. 180- later, the second At some time during the course of lip of the drill will perform the corresponding full line curve 82. It will thus be noted that the surface at the bottom of the drill hole is not a simple one which may be denominated a conical spiral, but instead has distortions out of the true conical and the true spiral shapes.

As the first drill lip enters upon its second revolution, represented in the second panel of Figure 6 by a full line and also represented by the dash line superimposed in the lefthand panelof Figure 6, it will be seen that this first lip proceeds to follow parallel to its prior course, andiremoves a chip 8% by gouging into the relative elevation left by the second lip during its preceding passage, and this chip 83 is rolled up into a tight conical shape 83a, which will not clog or jamthe drill.

180 later, the second lip performs the movement represented by its full line curve 82in the middle panel of Figure 6, and also represented by the dotted line curve 82a in the left hand panel of Figure 6. It will be noted that this lip has been removing a final portion of a chip 84 and causing it to curl into the shape shown at 84c, and that the second lip comes relatively out of or above the surface at the bottom of thehole, as provided by the cutting action of the'first lip in removing the chip 83, so that the chip 84 is terminated and forms a discrete particle. Substantially 180 later, the second lip, in following the dotted line curve 82a, again enters the work and cuts out a chip 85.

It will be noted that this successive effect of the lips, in cutting chips individually from the work, repeats itself so that each lip cuts out one chip during each revolution.

Upon rotation of the bushing 4|, its upper annular surface coacts with the lower surface of the spacer piece 45, so that this spacer piece is caused to change the plane of its upper surface and therewith to produce a change in the angular position of the outer sleeve 32, by a relative sliding of the spherical surfaces with respect to one'another. This adjustment causes a change in the angle of tilt between the axis of the inner sleeve 36 and the axis of the spindle l8; and by regulating this angle the amount of axial oscillation produced for each revolution of the spindle can be varied. As shown in Figure 2, the bushing l4 may have graduations to indicate the amount of this oscillatory movement. For example, with a small drill, the graduation may read in thousandths of an inch.

The bushing 4! is shown (Figure 2) as having a hole 60 parallel to its axis and receiving a spring 6| and a plunger 62 which plunger can engage in one of the series of depressions 63 in the lower surface of the spacer piece 45, wherewith to prevent undesired relative rotations of the bushing 4| and of the spacer piece 45, but permitting a relative rotation when adjustment is to be effected. i

As shown in Figure 5, the bushing 4| may have spanner wrench holes 64 if desired.

It is obvious that the invention is not limited to the illustrative form, but may be employed in many ways within the scope of the appended claims.

I claim:

1. In metal drilling and like machines, a frame, a support movable on said frame and means so to move the same, a drill spindle rotatable in said support about an axis substantially parallel to such movement, a sleeve embracing the spindle axis and rockable to angular positions relative to said spindle axis, bearing means on said movable 6, support for supporting the sleeve for rotation about its own prevailing axis, and an axial-thrusttransmitting driving element eccentrically mounted on said spindle and engaged with said sleeve,

' said element being effective to cause the spindle to drive said sleeve inrotation and also being effective to transmit thrusts between the spindle and sleeve, whereby to produce axial motion of the spindle compounded of the support and a cyclic movement caused by the angular position of the sleeve axis relative to the spindle axis.

2. In metal drilling and like machines, a frame, a support movable on said frame and means so to move the same, a drill spindle rotatable in said support, an outer sleeve having a spherical thrust bearing on the support, an inner sleeve rotatably carried by a thrust bearing in said outer sleeve and movable therewith in said spherical bearing so that its ownaxis may be at an angle to the spindle axis, means carried by the support and acting upon the said outer sleeve to hold the same against said support and at a predetermined arrgular relation of said axes, a thrust and driving element providing a universal pivot connection between the spindle and inner sleeve eccentric to both said axes and effective to cause the inner sleeve to rotate with the spindle and to transmit axial thrusts between said'sleeve and spindle.

3. In drilling and like machines, a frame, a support movable on said frame and means so to move the same, a spindle rotatable in said support, an outer sleeve having a spherical thrust bearing on said support, and a bushing reacting against said support and rotatable relative thereto about the spindle axis and having an inclined end surface effective for rocking said outer sleeve and for holding the same in rocked position, an inner sleeve carried by a thrust bearing to rotate in said outer sleeve, a ball providing a thrust and driving element between said spindle and inner sleeve and mounted eccentrically to both the spindle axis, and movable in a plane containing the center of said spherical bearing, and means reacting against the bushing for maintaining the ball engaged with the spindle and inner sleeve for causing the inner sleeve to rotate with the spindle.

4. In drilling and like machines, a frame, a support movable on said frame and means so to move the same, a spindle rotatable in said support, an outer sleeve having a spherical thrust bearing on said support, an inner sleeve carried by a thrust bearing to rotate in said outer sleeve, 9, ball providing a thrust and driving element between said spindle and inner sleeve and mounted eccentrically to both the spindle axis and the inner sleeve axis with the center of the ball in the radial plane throughthe sleeve axis containing the center of said spherical bearing, means carried by the support and acting upon the said outer sleeve to hold the same against said support and at a predetermined angular relation of said axes, and spring means for moving the spindle axially and thereby effective for maintaining engagement of said ball with the spindle and inner sleeve and assuring the rotation of the inner sleeve with the spindle.

5. In drilling and like machines, a frame, a support movable on said frame and means so to move the same, a spindle rotatable in said support, an'outer sleeve having a spherical thrust bearing on said support, an inner sleeve carried by a thrust bearing to rotate in said outer sleeve, ball providing a thrust and driving element besupport and at a predetermined angular relation:

of said axes, means for maintaining the ball engaged with the spindle and inner sleeve for causing the inner sleeve to rotate with the spindle, and means for holding the outer sleeve in a selected angular position in saidspherical bearing.

6. In drilling and like: machines having a frame, a quill,

on the quill and providing, aconcave annular spherical thrust surface around the spindle, an outer sleeve within the housing and fitting said spherical surface, an inner sleeve and thrust bearing means supporting the same in said outer sleeve, said inner sleeve having a depression at one end face, a rotatable bushing held insaid housing and spring-pressed bearing means engaged with the bushing and spindle and permitting relative axial movementthereof, acollar on the spindle and having av notch open toward said inner sleeve, a ball engaged in said depression and said notch for transmitting thrust and rotative forces between the inner sleeve and the spindle, the axes of the spindle and of the inner sleeve intersecting at the center for the spherical surface, and means actuated by the bushing during its rotation relative to the housing for rocking said outer sleeve on said spherical surface.

7. In metal drilling and like machines, a frame, a quill, means for feeding the quill onthe frame, a drill spindle rotatable in said quill and having a radial extension with a notch, a thrust member and bearing means for supporting the member with said member mounted for rotation about an axis at an angle relative to the axis of said spindle and for transmitting axial forces from the member to the quill, said member having a depression in its end face opposite said notch, a thrust transmitting ball located in said notch and depression and travelling about the spindle axis during the rotation of the spindle and effective to cause rotation of the member about its axis, and means effective tokeep said ball engaged with the surfaces of the notch. and depression.

8. In metal drilling and like machines having a frame, a quill, means for feeding the quill, and a drill spindle rotatable in said quill; the combination therewith of an outer sleeve embracing the spindle axis and rockable to angular positions relative to said spindle axis and having aspherical thrust bearing against the quill to resist drilling pressure, an inner sleeve and bearing means mounted on the outer sleeve for supporting the inner sleeve for rotation about'its own prevailing axis, said spindle having a collar with an edge notch, said inner sleeve having a depression in its end adjacent. the collar, a ball engaged in both said notch and said socket for transmitting end thrust between the inner sleeve and the spindle during drilling and also effective to cause the inner sleeve to rotate with the spindle, means effective during the rotation of the spindle for maintaining axial engagement of the ball with the inner sleeve and the collar, and means for holding the outer; sleeve in a predetermined angular position, whereby the axial movement of the spindle is a composite of the a spindle rotatable in said quill, means for feeding the quill, a housing feeding movement ofthe quill and of the cyclic movement of the ball in its travel during rotation of the inner sleeve.

9. In. metal drilling and like machines having a frame, a quill, means for feeding the quill, and a drill spindle rotatable in said quill; the combination therewith of an outer sleeve embracing the spindle axis and rockable to angular positions relative to said spindle axis and having at one end a spherical thrust bearing against the quill to resist drilling pressure, an inner sleeve and bearing means mounted on the outer sleeve for supporting the inner sleeve for rotation about its own prevailing axis, said spindle having a collar with an edge notch, said inner sleeve having a depression in its end adjacent the collar, a ball engaged in both said notch and said socket for transmitting end thrust between the inner sleeve and the spindle during drilling and also effective to cause the inner sleeve to rotate with the spindle, means effective during the rotation of the spindle for maintaining, axial engagement of the ball with the inner sleeve and the collar, a ring in said quill and engaged with the other end of the outer sleeve, means for preventing rotation of the ring relative to the quill, and a bushing having an inclined surface engaged with said ring and being rotatable in the quill and having an externally accessible partwhereby the bushing may be rotated, said quill having a thrust bearing for supporting said bushing against the ring, whereby the axial movement of the spindle is a composite of the feeding movement of the quill and of the cyclic movement of the ball in its travel during rotation of the inner sleeve; and

bearing means mounted on the outer sleeve for supporting the inner sleeve for rotation about its own prevailing axis, said spindle having a collar with an edge notch, said inner sleeve having a depression in its end adjacent the collar, a ball engaged in both said notch and said socket for transmitting end thrust between the inner sleeve and the spindle during drilling and also effective to cause the inner sleeve to rotate with the spindle, means eifective during the rotation of the spindle for maintaining axial engagement of the ball with the inner sleeve and the collar, a ring in said quill and engaged with the other end of the outer sleeve, means for preventing rotation of the ring relative to the quill, a bushing having an inclined surface engaged with said ring and being rotatable in the quill and having an externally accessible part whereby the bushing may be rotated, said quill having a thrust bearing for supporting said bushing against the ring, said ring having a plurality of depressions on its face engaged by the bushing, and a latch carried by the bushing and selectively engageable in one of said ring depressions whereby to hold the bushing in the corresponding rotated position thereof, whereby the axial movement of the spindle is a composite, of the feeding movement of the quill 2,458,929 10 and of the cyclic movement of the ball in its REFERENCES CITED travel during rotation of the inner sleeve, and 4 whereby the said cyclic movement is determined i g s g ggf gg are of record m the by the angular position of the outer sleeve and said angular position of the outer sleeve deter- 5 UN TED STATES PATENTS mined by the rotated position of the bushing. Number Name Date 2,252,176 Harris Aug. 12, 1941 CARLETON CLARK 2,328,542 Bates l- Sept. '7, 1943