AU704126B2 - Rotatable type machine tool - Google Patents

Description

WVO 1~l/3{ iN i/A l J tlj i96/001,! NI() IA I AIM I YI Of MA(!I!IN t 0)1 TECHNICAL FIELD This inpvention relates to machine tools of the rotatable type as are used, for example, in metal drilling or boring operations. In particular, the invention relates to rotatable tools in which a head, which usually carries a cutting means, is interchangeably assembled with a drive element, such as a shank that is directly mountable in a driving machine, or an intermediate piece, such as an extension or diameter reduction piece, which piece may be in turn assembled to a shank.

The invention is concerned with an interchangeable connection between the head and a drive element in such tools and with a mechanism for transversely adjusting the position of the head, and thereby usually a cutting means, relative to a drive element, for example to allow the tool to be adjusted to provide different boring or drilling diameters.

BACKGROUND ART In rotatable cutting tools having a cutting head that is separable from a driving element such as a shank, it is necessary that the driving interconnection between the two be as rigid as possible while allowing them to be relatively readily assembled and disassembled.

German published patent application DE 31 30 484 Al discloses a rapid change tool holder comprising a shank and a head. The head carries a cutting insert and is detachably clamped to the shank. The facing end surfaces of the shank and the head are shaped to provide a "multiple form-locking" of one to the other. The multiple form-locking that is disclosed comprises two protrusions on the shank, each having the cross section of an equilateral triangle, and two facing recesses in the head for receiving the protrusions, wherein the dimensions ard pattern of the recessed end is the exact negative of the protrusions on the shank. This multiple form-locking is described providing WOYWi n illi i N« I IA I Mr/JfII I l ll11Jll tld illlly, Io1W1 Wv Ilt1 fli lly W Illlb Illltm inllom ll l la !lllll d (1ll Il oinu litll h Uil )Ii l tXf1 I flrotitlllVo of tlh olIoli includes a tensioning bolt which passes axially through the shank and which has a formed end that is approximately T-shaped in cross section. This formed end is receivable in a correspondingly shaped mounting recess in the head.

However the mounting recess includes an end stop and the arrangement is such that the head can be assembled on the shank from one sideways direction only. Furthermore the head must be accurately positioned for the formed end to enter the mounting recess. This restricts the ease and therefore the rapidity with which one head can be exchanged for another on the shank.

DE 31 30 484 Al also discloses that the end stop of the mounting recess in the head may include a screw. This would allow sideways adjustment of the position of the head relative to the shank, but the amount of such adjustment is quite limited.

DISCLOSURE OF THE INVENTION The present invention seeks to provide an improved rotatable machine tool of the type having a head and a drive element which provides for diameter wise adjustment of the head. In comparison to the above described prior art, a machine tool according to the invention has improved rigidity and a head that is more readily able to be exchanged for another on a drive element.

According to a first aspect of the invention there is provided rotatable machine tool apparatus comprising: a head for carrying a cutting means, a drive element for the head, wherein the head and the drive element include complementary means for detachably mounting the head to the drive element, the complementary means including a transverse slideway, a bearing part for seating within the slideway and a clamping system, WO/ IJ i I ift I I( /AI I i/I IM I WlhiaL l lll 0 oriIju pcrIl rlirl Illia lllowrly arm j rlllol (111i 1Io (llitiillilllU yt:lll I llIM l1ldl Il() Il f III Ihla IiIU lIrI lil lmd It WruIlllitly OiUt(J)rn Ilici ttlltw o l(if |if()t(IN31rI¢ IIII" ll ittli II I II vo "l tl 1 nl ho iIio Ih I and whoerin thl clamping Bystom il op uerablu to reluau thu engagement force to allow sliding movement of the bearing part within the slideway for adjustment of the head transversely of the drive element.

The drive element could be a shank, or an extension piece or reduction piece that is connectable to a shank. Rotatable machine tools with which the invention is concerned normally include or are connectable to a shank that is mountable in a rotating drive means for the tool.

Typically the head will be for mounting a cutting means in the form of one or more removable carbide inserts which are attachable to the head by screws and each of which provides a cutting tip, although the invention includes apparatus wherein the head includes one or more integral cutting tips or is otherwise adapted for mounting a cutting means. For example the head could include a drill or collet chuck.

Preferably the transverse slideway is formed in the drive element and may be a slot within which a bearing part of the head seats, the bearing part being slidable within the slot. The slot and complementary bearing part may, in cross section, be of any suitable shape, preferably however, the slideway slot has sloping side surfaces which converge towards a base of the slot, and the bearing part includes sloped surfaces such that it wedgingly seats within the slot. The slope of the surfaces of the bearing part may correspond to the slope of the slot surfaces, in which case the base of the slot may comprise a channel section to provide clearance for the bearing part to wedgingly engage the slot.

The improved rigidity of the torque transmitting interconnection between the drive element and the head of the present invention is provided by the wedging of the bearing part within the slideway upon operation of the clamping system to apply a force that relatively draws the head into engagement with the drive element to secure the head in a selected position of transverse adjustment.

9ln/Ill I f/A I'M1ll(I) I I x0lfyr Ili0 1411lld1 u hYnhlI0r liii lii t n r(110 II I(rI|11 01 ill r(I M I w !1l t ll fii Iltlh ul llll w ijlli l !i I l 1I 1110Illl 1 0 lllti0ll i 0 1l Ili ri iKBO W I llolI I Ib t#ihkl~clolnJ Willi UIW (ifItllo lolJ wl Ilit (|lVO (11l01llll "fi ll1 10M oflnW IlloMllh it) associated with the other of the head or the drive element.

Preferably the clamping system includes a male member on the head, and wherein the drive element receives the male member and includes a screw means for interacting with the male member to draw the head into engagement with the drive element and secure the one to the other.

The male member may be an integral part of the head, preferably however it is a separate piece that is removably attachable to the head such that its position relative thereto is axially adjustable. This feature can assist the wedging engagement between the head and the drive element (and thus the rigidity of the connection) in that the position of the male member relative to the screw means is alterable thereby allowing the force that can be applied to the male member by the screw means, to draw the head into wedging engagement with the drive element to be increased. The interaction between the male member and the screw means may be via a ramp surface that is provided on each whereby operation of the screw means cams the male member, and thus the head, towards the drive element. Preferably the screw means also interlocks with the male member to secure the head to the drive element. Such an interlocking may be ensured by providing a circumferential groove in the male member within which the screw means seats. Thus the above described ramp surfaces for ensuring a wedging engagement between the head and the drive element may be provided by a frustoconical end on the screw means and sloping slides for the circumferential groove, the taper angle of each side of the groove being substantially equal with that of the side of the frustoconical end.

Preferably the attachment of the male member to the head is via a slide means associated with the head, whereby the male member and the head are relatively movable transversely of a longitudinal axis of the male member to provide the selected positions of transverse adjustment for the head.

Preferably the head includes locking means for securing the male member/slide means assembly in selected positions of transverse adjustment.

wO 96/33833JJ P'CTI/A' 6/002J.1 If'rtibly hli" iailo momtiir roemrovilbly Hlifirhd to 1i slidt mmins S1110 Ihldliil 1iconlrta C-mll t ho 1t1( (||oid tInw( l hy IWI) (11i)iih Bi| i (tWt t(.1II1(Io Ioln 11M m1iln iitimb>l/lII l n h MWItioinhy wl)ltr i)y 1 "loiK('iiJKiJiu" 1)f one screw and a corresponding "tightening" of the other may produce the above described transverse adjustment and the secure locking of the parts in a selected position of such adjustment. It will be appreciated that with such an opposed screw type arrangement for the locking means of the adjustment mechanism it is possible to provide very fine or, in other words, micro level adjustability for the head transversely of a drive element and the secure locking of the head in a selected adjustment position. Such micro adjustability and securement admits of high accuracy and thus the mechanism may be used in precision cutting tools.

The invention also includes an adjustment mechanism that can be used in a rotatable machine tool apparatus. Thus according to a second aspect the invention provides an adjustment mechanism for adjusting the position of a head of a rotatable machine tool means transversely relative to a drive element of the tool means, the mechanism including a slide means associated with the head and a male member, the male member being attached to the slide means and being adapted for connection to a drive element, the head also including locking means for securing the male member/slide means assembly in selected positions of transverse adjustment relative to the head.

A clamping system that includes a male member extending from the head and receivable in a bore within the drive element, and a screw means associated with the drive element that interlocks with the male member, as is described above, provides for ready assembly and disassembly of a head from a drive element. Simply by unscrewing the screw means to disengage it from the male member allows the male member to be withdrawn from the bore to thereby remove the head from the drive element. Assembly of a head to a drive element is achieved by inserting the male member into the bore (possibly turning the head to align the bearing part with the slideway) and tightening the screw means this is more readily accomplished than is possible with the described prior art.

WO 96/JJfHlJ I('I/A 1196/(l()2,14 iH1L IltflUtJ1!' I IUN UPI I Ir fit Ulit lI lll(3l(i0 ll will Il1W it tI00 1 iII1010, Iy wriny (If nU p1iildn (u1ly will) reference to the accompanying drawings which illustrate embodiments of the invention in the form of precision boring tools.

In the drawings: FIGURE 1 is an exploded view of a boring tool according to a first embodiment of the invention; FIGURE 2 is an end view of the head of the tool of Figure 1; FIGURES 3 and 4 show, respectively, a partially sectioned plan view and a side elevational view of an assembled boring tool similar to that shown in Figure 1; FIGURES 5 to 7 show, respectively, a plan, a side elevational and an end view of the head of the tool of Figure 1; FIGURES 8 and 9 show, respectively, an elevational and an end view of a shank for assembly with a head such as shown in Figure 1; FIGURE 10 is a sectional view along section line X-X on Figure 9 of an end portion of the shank; FIGURES 11 and 12, are, respectively, a plan and a side elevational view of a second embodiment of the invention; FIGURE 13 is an end view of the second embodiment as shown in Figure 11; and FIGURE 14 is a sectional view along section line XIV-XIV on Fig. 12.

BEST MODE FOR CARRYING OUT THE INVENTION In the drawings, corresponding features or elements in the various figures are indicated by a common reference numeral, except that in Figures 1the numerals are in the number series 1 to 99 whereas in Figures 11 to 14 they are in the number series 100 to 199.

Figure 1 shows a precision boring tool 1 in exploded perspective view.

The boring tool 1 comprises a head 2 and a shank type drive element 3 that WO 060),111.13 IM (6/(l0f1, 7 rm y loi mointdc in n drivo mrnonn (nol shown) for rotitinj tho tool hbotit ilt i ultitjlludli ol x I 1t drivo lonwi l Iinlid"r holdrii ,o il(n tioim i whl1Ii extends a tapered shank portion 'he specific form of shank shown in Figure 1 is not essential to the invention, thus a drive element 3 may include a shank portion having different forms for mounting in a drive means. For example, Figure 8 shows a drive element 3' having a holder portion 5 the same as in the Figure 1-4 embodiment, but which includes a shank portion 6' of cylindrical form having flats 14. Also, a drive element according to the invention may be an intermediate extension piece or reduction piece which is drivingly connectable to a shank for mounting in a rotating drive machine.

Holder portion 5 of drive element 3 includes a transverse slideway in the form of a slot 7 within which a bearing part 8 of head 2 seats. Slot 7 and bearing part 8 provide an arrangement for transmission of torque from drive element 3 to head 2 which carries a cutting means in the form of a removable cutting tip 9. The torque transmission arrangement 7-8 is such as to allow head 2 to be adjusted transversely of the longitudinal axis 4 of the drive element 3 (via a mechanism to be described below) to allow the boring tool 1 to be set for cutting different diameters, the radial extent of such adjustment being illustrated by dimension lines a and b shown in Figure 3.

Slot 7 is formed by opposed side surfaces 15 which slope inwardly towards a bottom channel portion defined by parallel walls 16 and a base 17.

The bottom channel portion is relatively shallow. Each surface 15 has a slope of 300 to axis 4 such that the included angle defined by surfaces 15 is 600.

The bearing part 8 of the head 2 is defined by opposite flats or surfaces 18 see Figure 2) which slope outwardly from an end face 19 of the head.

Each flat surface 18 has a slope of 300 to axis 4 such that together they define an included angle the same as that of slot 7, that is 600. The included angles of surfaces 15 and flats 18 are established to very close tolerances and each surface 15 and flat 18 is given a very smooth surface finish such that bearing part 8 of head 2 seats exactly within slot 7 of drive element 3, that is, the seating is such that effectively the whole area of each surface 15 lies in contact with a facing flat 18. The smooth finishes and matching accuracy of the WO 96/33833 PCT/A 96/((0023.1 (1 tWO lr I.o Itl Illl ia I 1 lWrI tI t 3illllb 1 lI dl 9/3 3 (Pdi ll wi I'IlF/ IU9I6I/2 o I) i l(lv to CIII ilri |i|l 'I A clamping system for securing head 2 to drive element 3 includes a male member 10 (which is attachable to head 2 via a slide 11) which is received within a bore 12 formed in drive element 3 in the base region 17 of slot 7. Male member 10 interacts with a clamping screw 13 in drive element 3 to clamp and interlock head 2 to the drive element 3, as will be described below.

Head 2 includes a transverse through bore 20 for receipt of a slide 11.

The diameter of slide 11 is matched to that of bore 20 and their respective surfaces are given a smooth finish such that slide 11 slidingly seats within bore that is, slide 11 is readily movable axially along bore 20 but has no play transverse to the axis. Slide 11 includes a centrally located threaded hole 21.

Head 2 also includes a slot 24 that extends between end face 19 and bore Male member 10 includes a stem 22 having a threaded end 23, the thread of which matches that of hole 21 in slide 11. A screwdriver slot 25 may be provided in the end face of stem 22. Male member 10 is connected to head 2 via passage of stem 22 through slot 24 and engagement of screw end 23 in threaded hole 21 of slide 11 within bore Male member 10 also includes a cylindrical end section 26 that has a circumferential groove 27 formed therein. Groove 27 has opposed side walls 28 which slope inwardly towards the base of the groove. Each side surface may slope at 300 such that the included angle of side surfaces 28 is 600.

Bore 12 in drive element 3 has a clearance end portion 29 of slightly larger diameter (see Figure 10) otherwise the diameter of bore 12 is accurately and smoothly finished to match the diameter of cylindrical end section 26, whic' is also accurately and smoothly finished, such that cylindrical end section 26 of male member 10 can tightly slide into bore 12. A small longitudinal groove (not shown) along the circumferential surface of end section 26 is provided for passage of air to facilitate insertion and removal of male member 10 into and from bore 12. A threaded hole 30 in holder portion 5 of drive element 3 intersects bore 12. Set screw 13 (which may be a grub screw having a WO 060 1111 't I \i'l'ItiiU 1 1 i

II

lltx (ijo ll llllVl llj tj(.ko ll h IVlllJ (1 (i lltloll).( lll .i l olll Al I (tiI) lll(.Itlltl tlIII)(l ()I which may be 600), is received in hole 30, and the relative positions of groove 27 on male member 10 and screw 13 in drive element 3 are such that the sloping surface of the frustoconical end 31 interacts with the innermost sloping side surface 28 of groove 27 such that on insertion of screw 13, the male member 10 and thus head 2 is cammed into engagement with drive element 3.

The bottom channel portion 16-17 of slot 7 and end portion 29 of bore 12 provide clearances such that the inwards force exerted on male member 10 by screw 13 (via ramp or camming surfaces 31 and 28) ensures that bearing part 8 of head 2 is wedgingly seated in slot 7 of drive element 3. The torque transmission interconnection that is so established is very rigid and enables excellent surface finishes to be obtained. Furthermore, bE.,,use the complementary wedge shapes of bearing part 8 and slot 7 are the same at 600, any loosening of screw 13 virtually immediately releases head 2 for transverse adjustment.

Slot 24 in head 2 is such that it allows transverse reciprocal movement of the male member-slide 10-11 assembly relative to head 2, the maximum possible extent of such movement being defined by contact of stem 22 with either end of the slot 24. Locking means for securing the slide assembly 10-11 in selected positions of transverse adjustment comprise two opposed set screws 31 and 33 (each of which may be a grub screw having a hexagon driving socket) the inner ends of which bear on stem 22 (as best illustrated in Figure Screws 32 and 33 are respectively received in threaded holes 34, in head 2 (see Figures 5-7) which open to the ends of slot 24.

The extent of slot 24 may be such that when stem 22 contacts one end, the axis of the stem is coaxial with axis 4 of the boring tool 1. When the stem is locked in this position on tightening of the opposing set screw 32 (after which the other screw 33 may be tightened into contact with stem 22), the tool will be set to its minimum machining diameter, which is the position shown in full in Figure 3 and is represented by radius a. The maximum machining diameter is then defined by the length of the slot 24 as is established when stem 22 contacts the other end of the slot which is represented by radius b in Figure 3.

WO I/ IIIIII N' I >'llll i! I I 10 Head 2 of the boring toolll lll l shown iin Figures 1-7,ll includes a nose por tion W l I4 1 W ill I lol(3IJ ll l llrt It l ly It II I I IlII l I$ tWll Il l I IrII t10 I l l l h 1li h tl f I iof I I I II l I |II l I llt I I .1 11, I 1 4 Ai 1 .ll w I w I I I I II IIIII i| l ll l I provdlo ollhiro ottroo or finu lovolu of adjustillllty for a cUlLting tool. I or example, for a precision boring tool as shown in the Figures, M6 size set screws having a thread pitch of 1 mm provide a suitabl, fine level of adjustability.

Head 2 of the boring tool 1 shown in Figures 1-7 includes a nose portion 36 having a surface 37 provided with a cutaway portion to provide a seat for the mounting thereon of a cutting insert 9. Surface 37 and its cutaway, and insert 9, are positioned and dimensioned such that the cutting tip of insert 9 and adjacent portions of the surface 37 lie in a diametrical plane of the head 2.

Other surfaces 38, 39 of the nose portion 36 are such as to establish clearances as appropriate for the nose portion 36 relative to a workpiece (not shown) to allow an efficient cutting operation to proceed. Also, radiassed transitions are provided between surfaces on the head 2 at appropriate locations to eliminate corners or edges that would otherwise cause stress concentrations that might lead to failure of the head. Figures 4 and 6 show alternative shapes for a transition from the main body of head 2 to surface 37 of nose portion 36. Thus, in Figure 4 a transition surface 40 having a large radius of curvature is shown, whereas in Figure 6 there is a small radius of curvature 41 at the transition.

Head 2 may also include an axial hole 42 for accessing a screwdriver slot 25 in stem 22 of male member The invention is not limited to the cutting means arrangement that is illustrated in the Figures and described herein. Thus the invention is intended to encompass all cutting means arrangements, either integrally formed with the head or including a separate cutting insert or bit that is mountable on the head, as are suitable for use in a rota,ble mac! 'ing tool composed of at least two parts, such as a cutting head and a drive element for the head.

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Claims (19)

1. Rotatable machine tool apparatus comprising: a head for carrying a cutting means, a drive element for thn head, wherein the head and the drive element include complementary means for detachably mounting the head to the drive element, the complementary means including a transverse slideway, a bearing part for seating within the slideway and a clamping system, r wherein the bearing part and the slideway are shaped and the clamping system is operable to force the bearing part to wedgingly engage the slideway for transmission of torque from the drive element to the head, and wherein the clamping system is operable to release che engagement force to allow sliding moverolent of the bearing part within the slideway for adjustment of the head transversely of the drive element.

2. Rotatable machine tool apparatus as claimed in claim 1 A ,in the slideway is formed in the drive element and the bearing part is an integral part of the head.

3. Rotatable machine tool apparatus as claimed in claim 1 or claim 2 wherein the slideway is a slot having sloping side surfaces which converge towards a base of the slot and the bearing part includes correspondingly sloped surfaces such that it seats within the slot

4. Rotatable machine toc! apparatus claimed in claim 3 wherein the base of the slot comprises a channel section to provide clearance for the bearing part to wedgingly engage the slot.

5. Rotatable machine tool apparatus as claimed in any one of claims 1 to 4 wherein the clamping system includes a male member and a screw means for interacting with the male member wherein the male member is WO ti i IIIt I t* I|/A Ifri'(Ir ll l Il I '1 ittioi 1lodl will 0i o l ot II1 i i t 1 IIhoo i li il li W 1101110 ttML rtl td wIllI) ilip n f H iM itritd i l t!i t(I VM tiliimi dl lll l

6. Rotatable machine tool apparatus as claimed in claim 5 wherein the male member is received within a bore in said other of the head or the drive element and wherein the male member and the screw means each include a ramp surface whereby operation of the screw means applies a camming force to the male member that acts in a direction along the axis of rotation of the machine tool apparatus.

7. Rotateble machine tool apparatus as claimed in claim 6 wherein the male member includes a circumferential groove having sloping side surfaces that converge towards a base of the groove and the screw means includes a frustoconical end for engaging the sloping sides of the circumferential groove.

8. Rotatable machine tool apparatus as claimed in any one of claims to 7 wherein the male member is associated with the head and the screw means is associated with the drive element.

9. Rotatable machine tool apparatus as claimed in claim 8 wherein the male member is detachably secured to the head.

Rotatable machine tool apparatus as claimed in claim 9 wherein the male member is secured to a slide means which is mounted in the head, whereby the male member and the head are relatively moveable transversely of a longitudinal axis of the male member to allow for adjustment of the head transversely of the drive element.

11. Rotatable machine tool apparatus as claimed in any one of claims 1 to 10 wherein the apparatus includes locking means for securing the head in selected positions of transverse adjustment relative to the drive element.

WO II I I iiA IJv/ii)l II lHtil~rtt+l!>|o (iirii+.lilliio lt+tu-il Jol|)| ll it) "M Irllrlftl III lm II w lInII appended to claim 10 wherein the locking means comprises screw means associated with the head for fixing the slide means and male member assembly in selected positions transversely of the head.

13. Rotatable machine tool apparatus as claimed in claim 12 wherein the screw means comprises two opposed screws which act on the male member, whereby the head is transversely adjustable relative to the drive element by a loosening of one screw and a corresponding tightening of the other.

14. Rotatable machine tool apparatus as claimed in any one of the preceding claims wherein the head comprises two relatively transversely moveable parts each of which carries a cutting means, wherein each part includes a substantially planar diametral surface in facing contact with that of the other part, and wherein the substantially diametral contacting surfaces are transversely aligned with the slideway.

15. An adjustment mechanism for adjusting the position of a head of a rotatable machine tool apparatus transversely relative to a drive element of the tool apparatus, the mechanism including a slide means associated with the head and a male member, the male member being attached to the slide means and being adapted for connection to a drive element, the head also including iocking means for securing the male member and slide means assembly in selected positions of transverse adjustment relative to the head.

16. An adjustment mechanism as claimed in claim 15 wherein the male member is detachably secured to the slide means.

17. An adjustment mechanism as claimed in claim 15 or claim 16 wherein the head includes a transverse through bore and an elongated slot that W iitm11111t I IA i'I 111011 t l In rlldo moolrh m Ih w(.ollt ilil IWOlitn 1i lin il n Mi nd Ilull innilr, ioiIllni |)in1tM« through the slot.

18. An adjustment mechanism as claimed in claim 17 wherein the locking means comprises screw means for acting on the male member and slide means assembly.

19. An adjustment mechanism as claimed in claim 19 wherein the screw means comprises two opposed screws which act on the male member, whereby the head is transversely adjustable relative to the drive element by a loosening of one screw and a corresponding tightening of the other. Rotatable machine tool apparatus substantially as described herein with reference to Figures 1 to 10 or Figures 11 to 14.