GB2356828A

GB2356828A - Cutting tool, such as a reamer.

Info

Publication number: GB2356828A
Application number: GB0024654A
Authority: GB
Inventors: Peter Yewman
Original assignee: Cogsdill Tool Products Inc
Current assignee: Cogsdill Tool Products Inc
Priority date: 1999-12-03
Filing date: 2000-10-09
Publication date: 2001-06-06
Also published as: GB9928466D0; DE10051848A1; FR2801824A1; IT1319502B1; GB0024654D0; ITMI20002609A1

Abstract

A cutting tool (1) comprises an elongate shank (2), one end (3) of which is adapted to be secured in a machine tool and the other end (4) of which constitutes a cutting head. A portion of the shank (2) intermediate its ends is provided with at least one adjustable screw device (9) comprising a screw (12) and a tapped bore (13), the screw (12) having a frusto-conical bearing surface (14) operable on a portion of the shank (2) to induce a bending moment (1A, 4A, 9A, 12A) on the shank (2), for eccentricity correction.

Description

2356828 Tide of the Invention Cutting Tool

Field of the Invention

This invention relates to a cutting tool particularly, though not exclusively, to a tool with a rotary cutting action resulting either from rotation of the tool, such as a reamer, or rotation of the workpiece.

Background of the Invention

Such cutting tools, typically for machining metal, require fixing in or to a spindle or chuck of a machine tool for powered rotation of the tool.

One industry-standard spindle employs side locking, where a radially movable screw clamp engages a recess in the shank. It is unavoidable however that with side locking the tool rotates eccentrically, with resultant loss of accuracy in the workpiece being machined. In the past this inaccuracy of side lock tooling systems has been accepted as unavoidable, and other measures have sometimes been necessary to negate the effect of eccentricity.

Object of the Invention A basic object of the present invention is the provision, in a cutting tool of a simple means of correcting the effect of eccentric tool mounting.

Summary of the Invention

According to the present invention there is provided a cutting tool comprising a shank, one end of which is adapted to be secured in a machine tool and the other end of which 2 constitutes a cutting head, characterised in that a portion of the shank intermediate its ends is provided with at least one adjustable screw device comprising a screw and a tapped bore, the screw having a frusto-conical bearing surface operable on a portion of the shank to induce a bending moment on the shank, for eccentricity correction.

Advantages of the Invention Once a rotary cutting tool has been secured in a machine tool, its eccentricity can be checked by industry-standard techniques to determine what screw device adjustment is necessary to induce a desired stress in a desired direction to produce a bending moment to negate the effect of the eccentricity, thereby ensuring that the effect of eccentricity is eliminated thus increasing the accuracy of workpiece machining, which is particularly advantageous where accuracy is paramount, such as in reaming operations.

Preferred or Optional Features The screw is rotatable about a radial axis.

One screw device is provided.

Two screw devices, located 180' apart, are provided.

Three screw devices, located 120' apart, are provided.

Four screw devices, located 90' apart, are provided.

The or each screw has a frusto-conical head.

The or each screw device comprises a parallel screw and a tapered, tapped bore.

The or each screw device comprises a tapered screw and a tapered, tapped bore.

With multiple screw devices these may either be located in the same plane, or at least some of the devices may be axially spaced along the shank, so as to minimise mechanical 3 weakness due to the presence of the screw devices, in any one plane, or circumferential zone of the shank.

The or each tapped bore has a frusto-conical mouth on which mouth the frusto-conical bearing surface is adapted to bear.

The or each tapped bore emerges at a parallel sided slot cut into the external periphery of the shank such that for a tool with four screw devices, four slots are provided, with the frusto conical bearing surface adapted to bear on a side wall of its slot.

The slot(s) is arcuate.

The slot(s) is tangential.

The or each tapped hole emerges at a grove that is either parallel sided walls or has mutually inclined side walls, with the screw device adapted to bear on the sidewall(s).

The groove is provided in an enlarged diameter portion of the shank.

The groove has a radiussed transition into its sidewalls.

The shank is a round, parallel shank.

The shank is solid for dry cutting operations.

The shank has a co-axial central bore for coolant/lubricant flow.

The shank has an enlarged diameter cutting head and an enlarged diameter clamping end.

The or each screw device is manually adjustable.

Brief Description of the Drawings

Figure 1 is a side elevation of a first embodiment of cutting tool in the form of a reamer, in accordance with the invention.

Figure 2 is a section on the line A - A of Figure 1.

Figure 3 is a view in the direction of arrow A of Figure 2; 4 Figure 4 corresponds to Figure I but shows a second embodiment; Figure 5 is a section on the line V - V of Figure 4; Figure 6 is a view in the direction of arrow B of Figure 5; Figure 7 is a section on the line VII - VII of Figure 4; Figure 8 is a view in the direction of arrow C of Figure 7; Figure 9 corresponds to Figure I but shows a third embodiment; Figure 10 is a section on the line X - X of Figure 9; Figure 11 is a view in the direction of arrow D of Figure 10; Figure 12 corresponds to Figure I but shows a fourth embodiment; Figure 13 is a section on the line XIII - XIII of Figure 12; and Figure 14 is a view of the direction of arrow E of Figure 13.

Figure 15 corresponds to Figures 1, 4, 9 and 12, but shows a fifffi embodiment mounted in an industry-standard ISO side-lock tool holder; Figure 16 is an enlargement of the portion of Figure 15 circled by the chain-dotted line; and Figure 17 corresponds to Figure 15, but shows an industry-standard HSK shank.

Detailed Description of the Drawings

In all embodiments, like parts or components are accorded like reference numerals.

A cutting tool in the form of a reamer I comprises a round, parallel shank 2 provided at one end with an enlarged diameter clamping end 3 of industry-standard profile, for clamping in or by an industry-standard tool, and at the other end with an enlarged diameter cutting head 4.

The cutting head 4, is provided, in known manner, with a replaceable and positionally adjustable reamer blade 5 eg of a carbide, and a plurality of axially extending, circumferential spaced-apart guide pads 6 adapted, in known manner, to engage the wall of the hole (not shown) to be reamed.

Also conventionally, the reamer 1 has an axis of rotation 7 and a coaxial central bore 8 for coolant/lubricant.

All the above is known or is conventional.

In accordance with the invention, the shank 2 is provided intermediate its ends, with at least one, and preferably four screw devices 9 spaced 90' apart, with two screw devices 9 in one plane 10, and two screw devices 9 in an adjacent plane 11, as can be readily appreciated from Figures 1, 4, 9 and 12.

Each screw device 7 comprises a screw 12 passing into a tapped bore 13, with the screw 12 having a frusto-conical bearing surface 14 adapted to engage a portion of the shank 2 and, depending on the extent of their being screwed radially inwardly or radially outwardly, exerting bending moments on the shank 2 as exemplified by arrows I A, 4A, 9A and 12A in Figures 1, 4, 9 and 17 to counter the eccentricity inherent in most if not all tool clamping systems.

In the embodiment of Figures 1 to 3, 15 and 16, the tapped bores 13, are each provided with a fi-usto-conical mouth 15 adapted to be engaged by the bearing surface 14 of an associated screw 12.

In the embodiments of Figures 4 to 8, the mouth 11 is extended transversely of the axis of rotation 7 by, in Figures 5 and 6 four arcuate slots 16 eg produced by a milling cutter, to define four pairs of spaced-apart sidewalls 17, with each pair engageable by the surface 14 of a screw 12, and in Figures 7 and 8 by four tangential slots 16A.

Instead of four slots 16 or 16A, Figures 10 to 14 indicated that the sidewalls 17 can extend over 3 60' by providing a circumferential groove 23 to define in Figures 10 and I I parallel sidewalls 17, or in Figures 13 and 14, mutually inclined sidewalls 17.

6 Arrows 18 in Figure 3 indicate typical directions in which bending movements can be applied to the shank 2 to correct eccentricity. Arrows 18A in Figures 6, 8, 11 and 14 illustrate four directions for the slotted embodiment.

In Figures 15 and 16, the enlarged head 3 is shown fitted into a receiving socket 19 of an industry-standard side-lock tool holder 20, and secured by a clamping screw 2 1. In this prefer-red embodiment, four screw devices 9 are provided at 90' spacings in the same circumferential plane 22, and to compensate for the reduced strength resulting from four tapped bores 13, the shank is of an increased diameter over a portion 2A in which the four screw devices 9, and hence four tapped bores 12 are provided, in a groove 23 having a radiussed transition into sidewalls 17, as best seen in Figure 16.

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Claims

1. A cutting tool comprising a shank, one end of which is adapted to be secured in a machine tool and the other end of which constitutes a cutting head, characterised in that a portion of the shank intermediate its ends is provided with at least one adjustable screw device comprising a screw and a tapped bore, the screw having a frusto- conical bearing surface operable on a portion of the shank to induce a bending moment on the shank, for eccentricity correction.

2. A cutting tool as claimed in Claim 1, wherein the screw is rotatable about a radial axis.

3. A cutting tool as claimed in Claim 1 or Claim 2, wherein one screw device is provided.

4. A cutting tool as claimed in Claim 1 or Claim 2, wherein two screw devices, located 180' apart, are provided.

5. A cutting tool as claimed in any one of Claim 1 or Claim 2, wherein three screw devices, located 120' apart, are provided.

6. A cutting tool as claimed in any one of Claim 1 or Claim 2, wherein four screw devices, located 90' apart, are provided.

7. A cutting tool as claimed in any preceding Claim, wherein the or each screw has a fi-usto conical head.

8 8. A cutting tool as claimed in any preceding Claim, wherein the or each screw device comprises a parallel screw and a tapered, tapped bore.

9. A cutting tool as claimed in Claims 1 to 7, wherein the or each screw device comprises a tapered screw and a tapered, tapped bore hole.

10. A cutting tool as claimed in Claims 4, 5 or 6 or any Claim appended thereto, wherein the multiple screw devices are located in the same plane.

11. A screw device as claimed in any one of Claims 4, 5 or 6 or any Claims appended thereto, wherein at least some of the devices are axially spaced along the shank-

12. A cutting tool as claimed in any preceding Claim, wherein the or each tapped bore has a frusto-conical mouth on which mouth the frust-conical bearing surface is adapted to bear.

13. A cutting tool as claimed in any one of Claims 1 to 11, wherein the or each tapped bore emerges at a parallel sided slot cut into the external periphery of the shank such that for a tool with four screw devices, four slots are provided, with the frust- conical bearing surfaces adapted to bear on a side wall of its slot.

14. A cutting tool as claimed in Claim 13, wherein the slot(s) is arcuate.

15. A cutting tool as claimed in Claim 13, wherein the slot(s) is tangential.

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16. A cutting tool as claimed in any one of Claims 1 to 11, wherein the or each tapped bore emerges at a groove.

17. A cutting tool as claimed in Claim 16, wherein the groove has parallel side walls.

18. A cutting tool as claimed in Claim 16, wherein the groove has mutually inclined side walls.

19. A cutting tool as claimed in any one of Claims 16 to 18, wherein the groove is provided in an enlarged diameter portion of the shank.

20. A cutting tool as claimed in any one of Claims 16 to 19, wherein the groove has a radiussed transition into its sidewalls.

21. A cutting tool as claimed in any preceding Claim, wherein the shank is a round, parallel shank.

22. A cutting tool as claimed in any preceding Claim, wherein the shank is solid for dry cutting operations.

23. A cutting tool as claimed in any one of Claims 1 to 21, wherein the shank has a coaxial central bore for coolant/lubricant flow.

24. A cutting tool as claimed in any preceding Claim, wherein the shank has an enlarged diameter cutting head and an enlarged diameter clamping end.

25. A cutting tool as claimed in any preceding Claim, wherein the or each screw device is manually adjustable.

26. A cutting tool substantially as herein before described with reference to Figures 1 to 3 of the accompanying drawings.

27. A cutting tool substantially as herein before described with reference to Figures 4 to 8 of the accompanying drawings.

28. A cutting tool substantially as herein before described with reference to Figures 9 to 11 of the accompanying drawings.

29. A cutting tool substantially as herein before described with reference to Figures 12 to 14 of the accompanying drawings.

30. A cutting tool substantially as herein before described with reference to Figures 15 and 16 of the accompanying drawings.

31. A cutting tool substantially as herein before described with reference to Figure 17 of the accompanying drawings.