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Title:
TURNING HEAD
Document Type and Number:
WIPO Patent Application WO/1998/045074
Kind Code:
A1
Abstract:
The invention relates to a turning head and, in particular, to a combined turning and chamfering head capable of performing bar turning, peeling, and chamfering operations. The head comprises a body portion (10), a first part (20), cutting tools (30) mounted for movement on the body portion (10), the positions of the cutting tools (30) being adjustable by means of the first part (20), the first part including means for facilitating simultaneous radial adjustment of the plurality of cutting tools in unison.

Inventors:
CARTER NIGEL (GB)
D AUBNEY ROBERT EDWARD (GB)
Application Number:
PCT/GB1998/000871
Publication Date:
October 15, 1998
Filing Date:
April 09, 1998
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
CCL SYSTEMS LTD (GB)
CARTER NIGEL (GB)
AUBNEY ROBERT EDWARD D (GB)
International Classes:
B23B5/16; B23B29/24; (IPC1-7): B23B29/24; B23B51/10
Foreign References:
EP0047362A11982-03-17
DE79490C
DE956007C1957-01-10
EP0462322A11991-12-27
Attorney, Agent or Firm:
Chugg, David John (15 Clare Road Halifax, West Yorkshire HX1 2HY, GB)
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Claims:
CLAIMS
1. A turning head comprising a body portion having a central axis of rotation, along which an elongate work piece to be machined may be aligned, and a first part associated with a plurality of cutting tools, which tools are circumferentially displaced from one another about said central axis of rotation and in a plane substantially perpendicular thereto, the head being arranged for performing, in use, a turning operation on an outer surface of the work piece, and being characterised in that the first part includes means for facilitating simultaneous radial adjustment of the plurality of cutting tools in unison.
2. A head according to claim 1, wherein each cutting tool comprises a first, cutting, end and a second, non cutting, end radially displaced from one another, each cutting tool being constrained by the first part and the body portion so as to be allowed to move in a radial direction during adjustment.
3. A head according to claim 1 or 2, the first part comprises a first member concentrically arranged with respect to an inner part of the body portion and further comprises a second member.
4. A head according to claim 3, wherein the first part is arranged for relative rotation with respect to said body portion during an adjustment operation.
5. A head according to claim 3 or 4, wherein the second member at least partially covers an end face of said head.
6. A head according to claim 3,4 or 5, wherein each of said cutting tools is arranged to move, during adjustment, within a corresponding radial slot formed in the inner part of said body portion.
7. A head according to any of claims 3 to 6, wherein said second member comprises a locating plate, said locating plate being securable to said first member and together with the first member being arranged to impart radial movement to said cutting tools during an adjustment operation.
8. A head according to any of claims 3 to 7, wherein the first member is provided with shaped tracks formed in an inner region thereto, the shaped tracks having a form such that as the cutting tools move during adjustment the second end of each cutting tool moves along a corresponding shaped track member.
9. A head according to claim 8, wherein the second member includes a number of shaped paths either in the form of grooves or upstanding portions whereby the shaped paths are adapted to impart said radial movement to said cutting tools during relative rotation of the first part with respect to the body portion.
10. A head according to claim 9, wherein the shaped paths are preferably in the form of a scroll having a first end which is both radially and circumferentially displaced from a second end thereof and which is adapted to cooperate with a portion formed in each cutting tool for movement along said scroll during relative rotation of the body portion and the first part so as to bring about said radial adjustment.
11. A head according to claim 7, or any of claims 8 to 10 as dependent thereon, wherein said locating plate and said cutting tools interact by means of grooves and upstanding portions, whereby each upstanding portion is arranged to sit within a corresponding groove.
12. A head according to claim 11, wherein during an adjustment operation the first member and locating plate, which are in fixed relation with respect to each other, are rotated with respect to the body portion to bring about said simultaneous radial adjustment of said cutting tools.
13. A head according to claim 12, wherein during said radial adjustment, the upstanding portions follow, locate and move within said grooves.
14. A head according to claim 13, wherein the upstanding portions may be provided on the locating plate to cooperate with grooves on the cutting tools.
15. A head according to claim 14, wherein when the first part is rotated in a first direction with respect to the body portion an outer part of each said upstanding portion is arranged to contact with an outer part of its corresponding groove to move each of said cutting tools radially outwardly.
16. A head according to claim 15, wherein when the first part is rotated in a second direction, opposite said first direction, the shaped tracks on the first member in contact with the second end of the cutting tools, are arranged to move said cutting tools radially inwardly.
17. A head according to claim 13, wherein the grooves are provided in the locating plate and each cutting tool is provided with an upstanding portion. In this case, when the first part is rotated in a first direction with respect to the body portion an inner part of each groove may be arranged to contact with an inner part of its corresponding upstanding portion to move said cutting tools radially outwardly, and when the first part is rotated in a second direction, opposite to said first direction, the shaped tracks on the first member in contact with the second end of the cutting tools are arranged to move said cutting tools radially inwardly.
18. A head according to claim 7, or any of claims 8 to 17 as dependent thereon wherein the locating plate is removable to provide access to the cutting tools so that cutting tools may be changed when required.
19. A head according to any of claims 11 to 17, wherein the cooperation of the upstanding portions and the grooves is such that, to adjust the radial positioning of the tools, the second part, clamped in position with respect to the first part, is rotated with respect to the body portion and the upstanding portions move within said grooves to cause movement of said cutting tools.
20. A head according to any of the preceding claims, wherein actuation of the first part to carry out adjustment is provided by means of a gearing system.
21. A head according to claim 20, wherein the gearing system comprises an actuator meshing with a toothed ring.
22. A head according to claim 21, wherein the toothed ring forms an integral part of the body portion or may comprise an addon part or parts.
23. A head according to claim 21 or 22, wherein the actuator comprises a rack and the toothed ring a pinion.
24. A head according to claim 21, 22 or 23 wherein the actuator comprises a worm drive.
25. A head according to any of the preceding claims, wherein coarse and fine adjustment is possible.
26. A head according to claim 25, wherein such coarse/fine adjustment is provided by means of outer and inner adjustment wheels of the actuator or by means of double ended actuator having a first end for coarse adjustment and a second end for fine adjustment.
27. A head according to any of claims 20 to 26, wherein coarse adjustment is provided by a worm drive operable from a first end and fine adjustment may be provided by a rack and pinion drive operable from a second end.
28. A head according to any preceding claim, wherein each cutting tool is provided with a removable cutting tip.
29. A head according to claim 28, wherein the cutting tips are removable by means of providing cartridges.
30. A head according to any of the preceding claims, wherein there is provided a second part comprising a chamfering tool mounted within the body portion such that a centre line thereof coincides with a central, rotational, axis of the body portion.
31. A head according to claim 30, wherein the chamfering tool comprises a plurality of angled cutting blades held by mounting means or there may be a single chamfering tip.
32. A head according to claim 30 or 31, wherein the chamfering tool is removably attached to the combined head.
33. A head according to claim 32, wherein the chamfering tool is associated with the head by means of a keyway so as to allow axial adjustment of the positioning of the chamfering tool.
34. A head according to claim 30,31,32 or 33, wherein the chamfering tool can be locked axially by axial locking means such as a grub screw extending through the body portion and bearing on part of the chamfering tool.
35. A head according to any of claims 30 to 34,wherein the chamfering tool is associated with mounting means.
36. A head according to any of claims 30 to 35, wherein the chamfering tool is provided with a plurality of cutting blades, each of which are angled by a predetermined amount with respect to the central axis.
37. A head according to claim 36, wherein the angle may be 45 degrees or any other preferred angle for forming a chamfered region on a leading end of a work piece.
38. A head according to claim 36, wherein the chamfer cutting blades may be mounted within a mouth region of the chamfering tool.
39. A head according to claim 38, wherein an inner most part of the mouth region is provided with an axially extending aperture, this aperture being provided with locating means for cooperation with a chamfering tool removing or adjusting device.
40. A head according to claim 39, wherein the locating means comprise the axially extending aperture being internally threaded so that it may cooperate with an externallythreaded pulling bar for removal of the chamfering tool.
41. A head according to any of claims 32 to 40, wherein the chamfering tool is removable from associated mounting means so that when removing the chamfering tool from the head, the mounting means stays within the head.
42. A head according to claim 40, wherein the mounting means and chamfering tool are associated with one another by means of a threaded engagement. Manipulation of a pulling bar may be arranged to unscrew the chamfering tool from the mounting means.
43. A head according to any of the claims, wherein the second part is removable from the first part.
44. A head according to any of the preceding claims, wherein, the first part has a through bore such that work pieces may be fed through the headthis is particularly desirable as it allows barpeeling operations to be carried out.
45. A head according to any of claims 31 onwards, wherein second part has a through bore to allow lubricant or coolant to pass therethrough.
Description:
TURNING HEAD The invention relates to a turning head. The invention is particularly, but not exclusively, concerned with a tool for enabling the combined turning and chamfering of metal rods, such as might be used in reinforced concrete structures. The invention may also find application in many other fields or activity such as in bar peeling where a bar of indeterminate length is to be turned during a continuous feed operation.

When forming reinforced concrete structures, there is often a requirement for joining metal reinforcing rods together. To enable such joints to be made, it is necessary to remove any ovalities from the reinforcing rods by turning them ("turning"is an operation whereby the diameter of a bar, rod etc., is reduced by cutting away an outer region of material during relative rotation of the bar and a cutter), chamfering the ends thereof, and then forming a thread on the skimmed end region so as to enable an internally threaded connecting sleeve to be used to join the two rod ends together.

In conventional systems, multiple processing stations are required to perform the skimming and chamfering operations. When performing each operation, it is necessary to establish a true centre line so that the rods are skimmed and chamfered in a correct concentric fashion.

Whenever it is necessary to change tools or move the work piece between operations such as skimming and chamfering, the true centre line is lost and this leads to extended setting up times and often less than ideal results. Also, the sheer length and general unwieldiness of reinforcing rods leads to handling difficulties.

From the above, it will be clear that there is a need for a tool which is capable of performing turning and chamfering operations without the need to move the work piece. It is desirable that such a tool should have a broad range of adjustment so as to be able to cope with work pieces having greatly differing diameters and turned lengths.

In the prior art, there has been provided a head which is capable of performing both the turning and chamfering operation. However, the prior art head has a very limited range of adjustment and has a number of setting up problems. For instance, this prior art head incorporates a plurality of cutting tools to provide the turning operation, but those cutting tools each need to be individually adjusted when changing diametric settings.

If any of those tools are incorrectly adjusted then the working life of the heads may be compromised or the work piece may be incorrectly cut-possibly resulting in reduced working life for the cutting tips of the tools or, more disastrously, strength reductions in the work piece which could result in premature failure.

There is also a need for a bar peeling device capable of handling bars of indeterminate length and supporting a wide variation of different diameter cuts using multiple cutting heads which are simultaneously adjustable.

It is an aim of embodiments of the present invention to overcome the abovementioned disadvantages of the prior art and provide a turning head and/or combined turning/chamfering head which is adjustable over a wide range. It is another aim of embodiments of the present invention to provide such a head which utilises an adjustment method whereby the cutting tools within the

head are readily/symmetrically, simultaneously and consistently adjustable.

According to a first aspect of the invention, there is provided a turning head comprising a body portion having a central axis of rotation, along which an elongate work piece to be machined may be aligned, and a first part associated with a plurality of cutting tools, which tools are circumferentially displaced from one another about said central axis of rotation and in a plane substantially perpendicular thereto, the head being arranged for performing, in use, a turning operation on an outer surface of the work piece, and being characterised in that the first part includes means for facilitating simultaneous radial adjustment of the plurality of cutting tools in unison.

Preferably, each cutting tool comprises a first, cutting, end and a second, non-cutting, end radially displaced from one another, each cutting tool being constrained by the first part and the body portion so as to be allowed to move in a radial direction during adjustment.

Preferably, the first part comprises a first member concentrically arranged with respect to an inner part of the body portion and further comprises a second member.

Preferably, the first part is arranged for relative rotation with respect to said body portion during an adjustment operation.

Preferably, the second member at least partially covers an end face of said head.

Preferably, each of said cutting tools is arranged to move, during adjustment, within a corresponding radial slot formed in the inner part of said body portion.

Preferably, said second member comprises a locating plate, said locating plate being securable to said first member and together with the first member being arranged to impart radial movement to said cutting tools during an adjustment operation.

Preferably, the first member is provided with shaped tracks formed in an inner region thereto, the shaped tracks having a form such that as the cutting tools move during adjustment the second end of each cutting tool moves along a corresponding shaped track member.

It is the purpose of the shaped tracks to form an abutment which the second ends of the cutting tools bear upon during machining operations of the head and to dictate the radial setting of each tool.

The second member preferably includes a number of shaped paths either in the form of grooves or upstanding portions whereby the shaped paths are adapted to impart said radial movement to said cutting tools during relative rotation of the first part with respect to the body portion. The shaped paths are preferably in the form of a scroll having a first end which is both radially and circumferentially displaced from a second end thereof and which is adapted to cooperate with a portion formed in each cutting tool for movement along said scroll during relative rotation of the body portion and the first part so as to bring about said radial adjustment.

Preferably, said locating plate and said cutting tools interact by means of grooves and up-standing portions, whereby each upstanding portion is arranged to sit within a corresponding groove. Preferably, during an adjustment operation the first member and locating plate, which are in fixed relation with respect to each other, are rotated with respect to the body portion to bring about said simultaneous radial adjustment of said cutting tools. Preferably, during said radial adjustment, the upstanding portions follow, locate and move within said grooves.

The upstanding portions may be provided on the locating plate to cooperate with grooves on the cutting tools. Preferably, when the first part is rotated in a first direction with respect to the body portion an outer part of each said upstanding portion is arranged to contact with an outer part of its corresponding groove to move each of said cutting tools radially outwardly.

Preferably, when the first part is rotated in a second direction, opposite said first direction, the shaped tracks on the first member in contact with the second end of the cutting tools, are arranged to move said cutting tools radially inwardly.

Alternatively, the grooves may be provided in the locating plate and each cutting tool may be provided with an upstanding portion. In this case, when the first part is rotated in a first direction with respect to the body portion an inner part of each groove may be arranged to contact with an inner part of its corresponding upstanding portion to move said cutting tools radially outwardly, and when the first part is rotated in a second direction, opposite to said first direction, the shaped tracks on the first member in contact with the second end of the cutting

tools are arranged to move said cutting tools radially inwardly.

The locating plate is preferably removable to provide access to the cutting tools so that cutting tools may be changed when required.

Preferably, the cooperation of the upstanding portions and the grooves is such that, to adjust the radial positioning of the tools, the second part, clamped in position with respect to the first part, is rotated with respect to the body portion and the upstanding portions move within said grooves to cause movement of said cutting tools.

Each cutting tool must be arranged so that it is freely adjustable with the groove and upstanding portions cooperating and yet precisely positionable so that during a cutting operation when the head is rotated at high speed and the second end of each cutting tool is hard against its shaped track, there is a very small amount of radial clearance between an outer edge of each groove and an outer edge of each corresponding upstanding portion. Too much clearance would mean that the adjustment operation would be inaccurate and too little clearance would make adjustment of the head tight and difficult to achieve.

"Minimal clearance"is that clearance which allows ease of adjustment coupled with good accuracy.

It will be appreciated from the above that the formation of the shaped paths on the second member and the shaped tracks on the first member are closely related.

The relationship between the shaped paths, which bring about the radial adjustment in position of the cutting tools, and the shaped tracks which provide the supports

against which the second ends of the cutting tools abut during turning operations may be determined empirically.

A spring loading mechanism may be provided such that each cutting tool is resiliently biased towards the shaped tracks, in which case, the tracks themselves could solely be utilised for radial adjustment of the cutting tools and the scrolls on the second member could be dispensed with.

Preferably, actuation of the first part to carry out adjustment is provided by means of a gearing system.

The gearing system may comprise an actuator meshing with a toothed ring.

The toothed ring may form an integral part of the body portion or may comprise an add-on part or parts.

The actuator may comprise a rack and the toothed ring may be a pinion.

The actuator may be a worm drive.

Preferably, coarse and fine adjustment is possible.

Such coarse/fine adjustment may be provided by means of outer and inner adjustment wheels of the actuator or by means of double ended actuator having a first end for coarse adjustment and a second end for fine adjustment.

Coarse adjustment may be provided by a worm drive operable from a first end and fine adjustment may be provided by a rack and pinion drive operable from a second end.

Each cutting tool may be provided with a removable cutting tip. The cutting tips may be removable by means of providing cartridges.

Preferably, there is provided a second part comprising a chamfering tool mounted within the body portion such that a centre line thereof coincides with a central, rotational, axis of the body portion.

The chamfering tool preferably comprises a plurality of angled cutting blades held by mounting means or there may be a single chamfering tip.

Preferably, the chamfering tool is removably attached to the combined head.

Preferably, the chamfering tool is associated with the head by means of a keyway so as to allow axial adjustment of the positioning of the chamfering tool.

Preferably, the chamfering tool can be locked axially by axial locking means such as a grub screw extending through the body portion and bearing on part of the chamfering tool.

The chamfering tool may be associated with mounting means.

Preferably, the chamfering tool is provided with a plurality of cutting blades, each of which are angled by a predetermined amount with respect to the central axis.

The angle may be 45 degrees or any other preferred angle for forming a chamfered region on a leading end of a work piece.

The chamfering blades may be mounted within a mouth region of the chamfering tool.

An inner most part of the mouth region may be provided with an axially extending aperture, this aperture being provided with locating means for cooperation with a chamfering tool removing or adjusting device.

The locating means may comprise the axially extending aperture being internally threaded so that it may cooperate with an externally threaded pulling bar for removal of the chamfering tool. The chamfering tool may be removable from the mounting means so that when removing the chamfering tool from the head, the mounting means stays within the head. The mounting means and chamfering tool may be associated with one another by means of a threaded engagement. Manipulation of the pulling bar may be arranged to unscrew the chamfering tool from the mounting means.

Preferably, the chamfering tool is arranged so as to accept work pieces of a wide range of diameters and to apply a chamfer to an end region thereof.

The second part is preferably removable from the first part. The first part may have a through bore such that work pieces may be fed through the head-this is particularly desirable as it allows bar-peeling operations to be carried out. The second part may have a through bore to allow lubricant or coolant to pass therethrough.

Preferably, the body portion is provided with means for attachment to a rotating shaft or flange so that the combined tool may be rotated at a given rate.

In carrying out turning operations non-rotating bars may be fed axially into a rotating head. Alternatively, rotating bars may be axially fed into a stationary head, or rotating bars have a non-rotating head fed onto them.

In a further alternative, stationary bars may have the rotating head fed axially onto them.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: Figure 1 is a perspective view showing a preferred embodiment of a combined cutting and chamfering head; Figure 2 is a front view of the combined head of Figure 1 showing a number of cutting heads and their interaction with an adjuster; Figure 3 is a cross-sectional view of the combined head taken along the plane defined by lines A-A'and B-B' of Figure 1; Figure 4 shows a locator plate for use with the head of Figures 1 to 3; and Figures 5A and 5B detailed views showing a mechanism for actuating adjustment positions of the cutting tools.

Referring to Figures 1 to 5, there is shown a combined turning and chamfering head in accordance with an embodiment of the present invention.

The combined head comprises, in general, a body portion 10, a first part 20, cutting tools 30 mounted for movement on the body portion, their positions being adjustable by means of the first part, and a second part 40 for carrying out a chamfering operation.

The first part 20 comprises a first member in the form of an adjuster ring 21 mounted concentrically with respect to a central axis X-X'of the body portion 10, a second member 23 (see Figure 4) which forms a locating plate and an actuator 22 for causing relative rotation of the adjuster 21 and locating plate 23 with respect to the body portion 10 about the central axis X-X'.

Cutting tools 30 are provided, each cutting tool 30 having a first end for supporting a cutting blade 31 and a second end 32. The cutting tools 30 are arranged to cooperate with the adjuster 21 and the locating plate 23 (see Figure 4) which is lockable to the front face of the adjuster 21 by means of screws 212 cooperating with slots 235 to 238. The cutting tools 30 cooperate with the locating plate 23 by means of shaped paths comprising upstanding portions 231-234 formed in the locating plate 23 locating within grooves 33 to 36 formed in the cutting tools 30. Shaped tracks 211 are provided recessed within an inner part of the end face of the adjuster 21 so that an upstanding wall of each of the shaped tracks is arranged to contact against the second end 32 of each head during a turning operation of the head (to be explained later).

It will be appreciated that if the-adjuster 21 is rotated in a direction shown by arrow Y of Figure 2 then the second, or outer, ends 32 of tools 30 will cooperate with their respective shaped tracks 211 so that each cutting tool 30 will move radially inwardly in the direction of arrows zi to Z4 of Figure 2 equally, when performing this"inward"adjustment outer surfaces 240-243 of the upstanding portions 231-234 interact with grooves 33 to prevent the cutting tools from"falling"inwardly.

If the adjuster 21 and associated locating plate 23 is rotated contrary to arrow"Y", the outer surfaces 240-243 of upstanding portions 231-234 cooperate with the grooves 33 to 36 move the tools contrary to arrows Zt to Z4 so as to perform an"outward"adjustment. Such relative movements of the adjuster 21 and locating plate 23 with respect to the stationary body portion 10 and resulting in the radial movement of the cutting heads 30 is brought about by an actuator mechanism 22 as shown in detail in Figures 5A and 5B and discussed later.

Referring primarily to Figures 1 and 3, the second part 40 comprises a chamfering tool 41 connected to a mounting means 42 by means of a stud 43.

The chamfering tool 41 has a number of cutting blades 44 disposed about central axis X-X'such that a work piece inserted in line with the central axis will have its end region chamfered according to the angle 0 subtended between cutting blades 44 and the central axis X-X'.

Mounting means 42 may be axially located within body portion 10 by means of a system comprising key 451 and grub screw 452. As an alternative, the mounting means 42 may form an integral part of the body portion 10. Axial location of the means 42 may be altered by loosening grub

screw 452 and pushing or pulling the chamfering tool using a pulling bar (to be explained below).

The plurality of angled cutting blades 44 form a mouth region 46 of the chamfering head 41. In an innermost region of the mouth 46 there is provided an axial aperture 47 which has an internal screw thread formed therein. The internal screw thread may be engaged by an externally threaded pulling bar such that the chamfering tool 41, complete with mounting means 42 may be removed from the body portion 10 should it be required, or the axial position thereof may be adjusted.

Alternatively, the chamfering tool 41 alone may be removed leaving the mounting means 42 in position. This may be done by keeping the grub screw 452 tight and using the threaded pulling bar to unscrew the tool 41 from the threaded stud 43 of the mounting means 42.

The stud is preferably hollow and this can then allow lubricant to flow through the interior of the head during operations to cool and lubricate the head and work piece.

Referring now to Figure 4, the locating plate 23 is shown. This locating plate 23 is provided with a plurality of shaped paths formed by upstanding portions 231-234. It is also provided with elongated slots 235- 238. The locating plate has a central aperture 239.

Referring now to Figures 2, 3 and 4, in combination, use of the locating plate 23 will be described.

The upstanding portions 231-234 are arranged to cooperate with grooves 33-36 formed in the cutting heads 30.

Means for actuating the adjuster 21 and locating plate 23 to rotate with respect to the body portion 10 during an adjustment operation will now be described in relation in particular to Figure 2, Figure 3 and Figure 5.

As can be seen from Figure 2, the cutting tools 30 run in grooves provided in an end most part 11-of the body portion 10. As already explained, rotation of adjuster 21 and locating plate 23 in direction Y, whilst body portion 10 remains stationary, results in the heads 30 moving inwardly in a direction of arrows Z, to Z4. Rotation of the adjuster 21 and plate 23 in the opposite direction to that shown by arrow Y allows heads 30 to move outwardly in the opposite directions to arrow Zl to Z4. Outward movements of the cutting tools 30 are caused by the locating plate 23, by the outer walls of the upstanding portions 231-234 interacting with the outer walls of the grooves 33-36 and inward movements are caused by the shaped tracks 211 of the adjuster 21 bearing upon the second ends 32 of the cutting tools 30. In understanding this means of adjustment it should be borne in mind that the upstanding portions 231-234 are narrower than the grooves 33-36 so that there is no interaction between inner parts of the upstanding portions 231-234 and grooves 33-36.

To bring about the relative rotation of the adjuster 21 and locating plate 23 with respect to the body portion 10, there is provided an actuator 22 whose general form is shown in Figure 5A and in detail in Figure 5B.

An external worm threaded region 221 of actuator 22 is arranged to mate with gear teeth 102 of a geared region 101 of the body portion 10. The gear teeth 102 are shown in Figure 5A (but omitted from Figure 5B for the sake of

clarity) and are provided around an external peripheral region of the geared region 101 which is a part which is directly attached to the body portion 10. The geared region does not need to extend around the full circumferential extent of the body portion, but of course its positioning and configuration are arranged so as to enable a sufficient range of relative rotation between the body portion 10 and adjuster/locating plate to give a full range of movement of the cutting tools 30.

The adjustment mechanism is actuated as follows.

In order to make a coarse adjustment, a square 224 formed at a coarse adjustment end of the actuator 22 is rotated to use the actuator 22 as a worm drive. Use of the worm drive causes the relative positions of body portion 10 and first part 20 to shift. In turn, as there is relative rotation, for instance in the direction of arrow Y shown in Figure 2, the cutting tools 30 will move inwardly in directions Z, to Z4 so as to move towards the central axis of rotation.

The actuator 22 is further provided with fine adjustments means, the fine adjuster is provided by the square 225 formed at the opposite end of the adjuster 22 to the coarse adjuster square 224.

Figure 5B shows, in more detail, the fine adjustment mechanism. Square 225 forms an end region of threaded member 223, which is a generally cylindrical member having an external thread formed thereon. The thread is relatively fine as compared to the threaded region 221 of the coarse adjuster. Member 223 is associated with the main region of the actuator 22 and is arranged so that threaded member 223 can freely rotate independently of

worm region 221 by means of a protruding member which bears against an internal shoulder region 226 of the actuator 22 so that as square 225 is rotated in direction P, the whole of the actuator 22 moves in an axial direction denoted by arrow Q and this in turn pushes rather than turns the worm drive formed by region 221 so as to make it, in combination with the geared region 101 act as a rack and pinion to provide fine adjustment means.

A combined turning and chamfering operation will now be described.

The combined head is mounted for rotation on a rear machine by attaching its rear flange 12 to the mounting flange of a lathe or similar.

Firstly, a work piece such as a reinforcing rod for use in concrete reinforcing systems is selected. The work piece is aligned so that its central axis coincides with the axis of rotation X-Xl of the combined head. The cutting tools 30 are adjusted for a given diameter by the coarse/fine actuator 22 so that irregularities from an end region of the reinforcing rod may be removed during a turning operation.

The rod may then be fed into the end of the head through aperture 239 and the head rotated. As the rod is fed in, it is automatically skimmed by cutting tools 30 and then the end region chamfered by chamfering tool 41, the length of turned portion being preset by the axial setting of the chamfering tool 41, relative to the cutting tips 31.

It will be appreciated that the apparatus of the present invention offers many advantages over the prior

art. It is able to carry out turning and chamfering operations in a single go and to carry these out rapidly permitting a vast increase in work rate.

It is adjustable over a wide range and adjustment may be carried out easily, each of the cutting heads moving in unison.

By combining the operations of turning and chamfering the centre line is not lost. For bar peeling operations the head may be supplied without a chamfering tool or the chamfering tool may be an optional extra.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.