Reinforced metal slitter body having insert pockets

Abstract

A metal slitter body including a cylindrical body portion and cutting body portions extending outwardly from and integrally formed with the cylindrical body portion. The cutting body portions each include an insert pocket having an insert receiving slot, first and second clamping jaws and a slot end. The slitter body further including a reinforcement portion extending from the cylindrical body in an outward radial direction further than each slot end.

Claims

1. A metal slitter body comprising: a cylindrical body portion having a rotation axis (A.sub.R) extending through a center thereof and defining a direction of rotation (D.sub.R) thereabout; a plurality of cutting body portions extending outwardly from the cylindrical body portion; opposing first and second body side surfaces; and a body peripheral surface extending therebetween; the slitter body having a unitary one-piece construction and being devoid of screw holes; a width direction is defined parallel with the rotation axis (A.sub.R); an outward radial direction is defined from the rotation axis (A.sub.R) towards the body peripheral surface; an inward radial direction is defined opposite to the outward radial direction; a tangential direction extends perpendicular to the inward and outward radial directions; an imaginary bisecting plane (P) is defined as extending perpendicular to the rotation axis (A.sub.R) and through the center of the plurality of cutting body portions; each of the plurality of cutting body portions comprising: a cutting body portion width CBW which is measurable along the width direction and from the first body side surface to the second body side surface; and an insert pocket configured for resilient clamping; each insert pocket comprising: an insert receiving slot; a first clamping jaw located on one side of the insert receiving slot; a second clamping jaw being smaller than the first clamping jaw and located on an opposite side of the insert receiving slot to the first clamping jaw; and a slot end connecting the first and second clamping jaws; the slitter body further comprises a reinforcement portion adjoining the cylindrical body; the slitter body, along the reinforcement portion, having a reinforcement portion width RW; the reinforcement portion width is greater than the cutting body portion width CBW; characterized in that: in a side view of the slitter body, the reinforcement portion defines a circular contour; and in each of the plurality of cutting body portions, the reinforcement portion extends in the outward radial direction (D.sub.O) past the inward-most point of the slot end, adjacent to the second clamping jaw.

2. The slitter body according to claim 1, wherein, in each of the plurality of cutting body portions, the reinforcement portion extends in the outward radial direction past the inward-most point of the slot end, adjacent to the first clamping jaw.

3. The slitter body according to claim 1, wherein: the imaginary bisecting plane (P) extends perpendicular to the rotation axis (A.sub.R) and through the center of the plurality of cutting body portions; and the reinforcement portion extends in the width direction from the bisecting plane (P) only in a single direction.

4. The slitter body according to claim 1, wherein the insert receiving slot extends in the inward radial direction more than it extends in the tangential direction.

5. The slitter body according to claim 1, further comprising a flexibility groove located between each pair of adjacent cutting body portions.

6. The slitter body according to claim 5, wherein each flexibility groove extends in the inward radial direction more than it extends in the tangential direction.

7. The slitter body according to claim 5, wherein each flexibility groove extends from a part of the cutting body portion located radially outward of the reinforcement portion in the inward radial direction to a part of the reinforcement portion.

8. The slitter body according to claim 1, wherein the cutting body portion width CBW fulfills the condition: CBW<0.70 mm.

9. The slitter body according to claim 8, wherein the cutting body portion width CBW fulfills the condition: CBW≤0.60 mm.

10. The slitter body according to claim 8, wherein the cutting body portion width CBW fulfills the condition: CBW>0.30 mm.

11. The slitter body according to claim 10, wherein the cutting body portion width CBW fulfills the condition: CBW≥0.40 mm.

12. The slitter body according to claim 1, wherein the reinforcement portion width RW fulfills the condition: RW≤1.5 mm.

13. The slitter body according to claim 12, wherein the reinforcement portion width RW fulfills the condition: RW≤1.1 mm.

14. The slitter body according to claim 12, wherein the reinforcement portion width RW fulfills the condition: RW≥0.8 mm.

15. The slitter body according to claim 14, wherein the reinforcement portion width RW fulfills the condition: RW≥0.9 mm.

16. The slitter body according to claim 1, wherein a wall projection protrudes into the insert receiving slot and defines an extended slot portion which constitutes a radially inward-most portion of the insert receiving slot.

17. The slitter body according to claim 16, wherein the extended slot portion has a round shape.

18. A slitter comprising: a slitter body according to claim 1, and a cutting insert mounted in each of the insert pockets; wherein each cutting insert comprises a cutting edge having a cutting edge width CW extending further in the width direction further than the cutting body portion width CBW.

19. The slitter according to claim 18, wherein each cutting insert comprises only a single cutting edge.

20. The slitter according to claim 18, wherein, in a side view, each cutting insert has a basic straight elongated shape.

21. The slitter body according to claim 1, further comprising a flexibility groove located between each pair of adjacent cutting body portions, no portion of the flexibility groove being located between the rotation axis (A.sub.R) and a radially inward-most point of the insert receiving slot closest to that flexibility groove.

22. The slitter body according to claim 21, wherein: the cutting body portion width CBW fulfills the condition: 0.7 mm>CBW>0.3 mm; and the reinforcement portion width RW fulfills the condition: 1.5 mm≥RW≥0.8 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of a slitting tool according to the present invention;

(2) FIG. 2A is a top view of a cutting insert of the slitting tool in FIG. 1;

(3) FIG. 2B is a front view of the cutting insert in FIG. 2A;

(4) FIG. 2C is a side view of the cutting insert in FIGS. 2A and 2B;

(5) FIG. 3A is a side view of a slitter body of the slitting tool in FIG. 1;

(6) FIG. 3B is a front view of the slitter body in FIG. 3A;

(7) FIG. 4A is a side view of the slitting tool in FIG. 1;

(8) FIG. 4B is a front view of the slitter body in FIG. 4A; and

(9) FIG. 5 is a side view of a slitting tool according to another embodiment of the present invention.

DETAILED DESCRIPTION

(10) Reference is made to FIG. 1, which illustrates a first preferred embodiment of a slitting tool 10.

(11) The slitting tool 10 comprises a metal slitter body 12, and one or more cutting inserts 14 (all of which are identical in the preferred yet non-limiting example) mounted to the slitter body 12. The cutting inserts 14 are typically made of cemented carbide.

(12) Referring to FIGS. 2A to 2C, one of the cutting inserts 14 will be described in detail.

(13) The cutting insert 14 comprises a cutting portion 16 and a shank portion 18 extending therefrom.

(14) The cutting portion 16 comprises a rake surface 20 (above which chips are intended to flow) and front, first-side and second-side relief surfaces 22A, 22B, 22C tapering inwardly with increasing distance from the rake surface 20.

(15) The rake surface 20 preferably has a chip-forming arrangement 24.

(16) A cutting edge 26 extends along the intersection of the rake surface 20 and front, first-side and second-side relief surfaces 22A, 22B, 22C.

(17) The shank portion 18 comprises an upper shank surface 28A, a lower shank surface 28B, first and second side shank surfaces 28C, 28D connecting the upper shank surface 28A and lower shank surface 28B, and a rear shank surface 28E connecting the upper, lower, first and second side shank surfaces 28A, 28B, 28C, 28D.

(18) The overall shape of the cutting insert 14, and particularly the shank portion 18 thereof is a basic straight elongated shape.

(19) More precisely, the cutting insert 14 is elongated along an elongation axis AE extending through the rear shank surface and the front relief surface.

(20) The width of a slit (not shown) cut by the slitting tool 10 (in a workpiece) corresponds to the cutting edge width CW. As the cutting insert 14 comprises only a single cutting edge 26, the entire cutting insert 14 can be located within the slit and fully occupies the latter's width.

(21) This is because the cutting edge with its cutting edge width CW extends further in the width direction on both sides of the bisector plane P, than the cutting body portion of the metal slitter body 12 with its cutting body portion width CBW (the cutting body portion width CBW is only shown for understanding or comparison in the enlarged view of FIG. 2A, it will be understood it relates to the slitter body 12 and not the cutting insert 14).

(22) In this preferred example the cutting edge width CW is 0.6 mm, which is smaller than is known for slitting tools to the present applicant.

(23) A maximum length ML of the cutting insert 14, in the top view of 2A, is approximately 6 mm. In a slightly rotated view without the rear shank surface being visible the length would be about 5.8 mm.

(24) Referring also to FIG. 4A, the cut depth AP of the slitting tool 10 in this example corresponds basically to the maximum length ML.

(25) For the reasons explained above, the upper shank surface 28A is formed with a tapered sub-surface 30A (FIG. 2A), and the opposite lower shank surface 28B is formed with a tapered sub-surface 30B (FIG. 2B). These tapered sub-surfaces 30A, 30B facilitate sliding mounting of the cutting insert 14 on corresponding tapered first and second clamping sub-surfaces 42, 44 (described below) of insert pockets 38 formed on the slitter body 12.

(26) Such tapered sub-surfaces are known in the art, but for the present invention it is particularly advantageous for the two opposing surfaces (upper and lower shank surfaces) to be formed with tapered sub-surfaces in view of the particular difficulty with mounting the cutting inserts 14 (noting that there also exists cutting inserts which have only one tapered sub-surface, and are considered more stable since they have a planar sub-surface rather than a second tapered sub-surface).

(27) Referring to FIGS. 3A and 3B, the slitter body 12 will now be described.

(28) The slitter body 12 comprises a cylindrical body portion 32 having a rotation axis A.sub.R extending through the center thereof and defining a direction of rotation D.sub.R thereabout and a plurality of cutting body portions 34 extending outwardly from the cylindrical body portion 32.

(29) The slitter body 12 comprises a first body side surface 36A and an opposing second body side surface 36B, and a body peripheral surface 36C extending therebetween.

(30) A width direction D.sub.W is defined parallel with the rotation axis A.sub.R.

(31) An outward radial direction D.sub.O is defined from the rotation axis A.sub.R towards the body peripheral surface 36C.

(32) An inward radial direction D.sub.I is defined opposite to the outward radial direction D.sub.O.

(33) A tangential (“circumferential”) direction D.sub.T extends perpendicular to the inward and outward radial directions along the outermost portion of the body peripheral surface 36C.

(34) An imaginary bisecting plane P is defined as extending perpendicular to the rotation axis A.sub.R and through the center of the plurality of cutting body portions 34.

(35) The cutting body portions 34 are identical and hence the arrows designating portions thereof may be directed to different cutting body portions 34 simply for ease of visibility.

(36) A flexibility groove 35 extends between each of the adjacent cutting body portions 34.

(37) Each of the plurality of cutting body portions 34 comprises: a cutting body portion width CBW which is measurable along the width direction D.sub.W and from the first body side surface 36A to the second body side surface 36B. More specifically, the cutting body portion width CBW only applies to those portions of the cutting body portions 34 which are not adjacent to the reinforcement portion. In other words, the cutting body portion width CBW does not include the width of the reinforcement portion.

(38) Each cutting body portion 34 comprises an insert pocket 38.

(39) Each insert pocket 38 comprises an insert receiving slot 40; a first clamping jaw 40A, a second clamping jaw 40B and a slot end 40C connecting the first and second clamping jaws 40A, 40B. In the embodiments shown, the second clamping jaw 40B is circumferentially forward of the first clamping jaw 40A, in the direction of rotation D.sub.R.

(40) It will be understood that the first clamping jaw 40A has a first clamping sub-surface 42 facing the insert receiving slot 40 and being formed with a tapered shape configured (as known in the art) to engage the tapered sub-surface 30B of the lower shank surface 28B of the cutting insert 14.

(41) Similarly, the second clamping jaw 40B has a second clamping sub-surface 44 opposite the first clamping sub-surface 42, and facing the insert receiving slot 40. The second clamping sub-surface 44 being formed with a tapered shape configured (as known in the art) to engage the tapered sub-surface 30A of the upper shank surface 28A of the cutting insert 14.

(42) The slitter body 12 further comprises a reinforcement portion 46 adjoining the cylindrical body portion 32. The reinforcement portion 46 extends, in the radially outward direction D.sub.O, towards the plurality of cutting body portions 34. In the embodiment seen in FIG. 3B, the second body side surface 36B is formed on the reinforcement portion 46. The slitter body 12 is wider at the reinforcement portion 46 than at the extremity of the cutting portion 34 having a cutting body portion width CBW. The reinforcement portion 46 has a reinforcement portion width RW. The overall width OW of the slitter body 12 (where there is a reinforcement portion 46) is the sum of the cutting body portion width CBW and the reinforcement portion width RW. As seen in the side view of FIG. 3A, the reinforcement portion 46 can appear circular, and thus have continuous rotational symmetry (i.e., rotational symmetry at all angular displacements) about the rotation axis A.sub.R. However, in other embodiments, the reinforcement portion 46 may instead have discrete rotational symmetry (i.e., rotational symmetry only at discrete angular displacements).

(43) In the embodiments shown, the reinforcement portion 46 is formed on only one side of the bisecting plane P. One feasible alternative design would be for a reinforcement portion (not shown) to be symmetric about the bisecting plane P. However, such an alternative design would require both sides of the slitter body 12 to be machined, and so is less preferred.

(44) The reinforcement portion 46 preferably, but optionally, has a basic disc-shape which extends to an inner boundary 48 at which it still has the reinforcement portion width RW. In a further radially outward position the reinforcement portion 46 preferably, but optionally tapers (i.e. has a peripheral chamfer 49) towards the bisecting plane P to the cutting portion 34 at an outer boundary 50. As seen in the side of view of FIG. 3A, at the inner boundary, the reinforcement portion 46 defines a circular contour 68. Furthermore, this circular contour 68 is located, in the radially outward direction D.sub.O, no further than half way up the radial extent of any of the insert receiving slots 40. As seen in the figures, the insert receiving slots 40 and the flexibility grooves 35 all straddle the inner and outer boundaries of the reinforcement portion 46. However, no portion of a flexibility groove 35 is located between the rotation axis A.sub.R and the insert receiving slot 40 closest to that flexibility groove 35.

(45) It will be understood that the slitting tool 10 cannot enter a workpiece radially inward of the outer boundary 50. This is because the slitter body 12 becomes wider radially inward of the outer boundary 50 where the reinforcement portion 46 commences. And while the cut width CW of the cutting insert 14 is wider than the cutting body portion width CBW, it is not wider than the slitter body 12 where the reinforcement portion 46 is present.

(46) Referring also to FIGS. 4A and 4B, some perspective will be given as to the dimensions of the preferred embodiment shown.

(47) The cut depth AP (measured to about the outer boundary 50 in the inward direction D.sub.I) is about 6 mm. The diameter D is about 50 mm. This means that the unutilized depth UD of the slitting tool 10 is about 44 mm or 88%.

(48) However, reverting to FIG. 3A, since the reinforcement portion 46 extends a first radial length R1 (measurable from the rotation axis A.sub.R to the outer boundary 50) which is greater than a second radial length R2 (measurable from the rotation axis A.sub.R to the inward-most point 52 of the slot end 40C) the reinforcement portion 46 provides the relatively smaller second clamping jaw 40B with enough constructional strength to consistently clamp the cutting insert 14 thereto. In other words, the reinforcement portion 46 protects the second clamping jaw 40B, for example from bending forces that may be experienced during mounting of an insert to the insert pocket 38.

(49) Preferably, but optionally, each insert pocket 38 can be associated with an ejection hole 54 used to pry open the resilient insert pocket 38 to remove a cutting insert 14 therefrom.

(50) Referring to FIG. 5, a second preferred embodiment of a slitting tool 100 will now be described.

(51) The slitting tool 100 comprises a metal slitter body 102, and one or more cutting inserts 14 (which are identical to those described above).

(52) The basic construction of the slitter body 102 is similar to the slitter 12 described above except that an insert receiving slot 104 has an extended slot portion 106 which protrudes in the inward radial direction DI.

(53) The extended slot portion 106 allows the relatively smaller second jaw 108 to have a greater jaw thickness T and hence more structural strength.

(54) Similar to the first embodiment, the reinforcement portion 110 extends further radially outward than an inward-most point 112 of the slot end 114. And again, the reinforcement portion 110 extends to the second clamping jaw 108.

(55) In the non-limiting embodiment shown in FIG. 5, both a relief portion 116 of the insert receiving slot 104 (i.e. the portion of the insert receiving slot 104 still designed to accommodate the cutting insert 14 but leaving a relief space therefor) and the extended slot portion 106 have basic round shapes. As seen in FIG. 5, a wall projection 118 extends partially between the relief portion 116 and the extended slot portion 106.

(56) A first radial length LS1 of the extended slot portion 106 is roughly equivalent to a second radial length LS2 of the relief portion 116 (i.e. the radial length of the space not accommodated by the cutting insert 14).

(57) As will be understood, providing the extended slot 106 may be one way to increase the depth of cut which in FIG. 5 is designated AP2.

(58) The description above includes exemplary embodiments but does not exclude non-exemplified embodiments and details, all of which fall within the claim scope of the present application.