GB2158374A - Machine tool socket and spigot coupling - Google Patents

Abstract

A machine tool is described having a tool head 10 and a tool body 30. A frustoconical portion 14 of the tool head 30 is received within a corresponding internal bore 32. Two lugs 18, 19 are formed on a substantially T-shaped peg 16 mounted on the frustoconical portion 14 of the tool head 10 and are receivable through a slot 44 in an insert 36 within the tool body 30. A turn of less than 180 DEG locks the tool head 10 and the tool body 30 together. <IMAGE>

Description

SPECIFICATION Machine tool The present invention relates to a machine tool and in particular to a tool head and a tool body which may be quickly locked together or released from one another with a turn of less than 1 80' and approximately 90 .

In the present day and age, efficient pro duction on machine tools requires quick and easy changing of tools. In addition to quick and easy tool changing, it is an absolute requirement that the tool holder and tool head are rigidly connected to provide accurate loca tion and positive engagement. positive en gagement allows transmission of the forces from the tool holder to the tool head without any loss through the coupling arrangement.

According to the present invention, there is provided a machine tool having a tool head and a tool body which may be quickly locked together or released from one another, the tool head being capable of positive non-rota tional engagement with the tool body, the tool head and tool body having locking means therebetween comprising at least one locating lug and a locating lug receiving means capable of receiving the lug and locking it in position to draw the tool head and tool body together and to prevent the withdrawal of the tool head from the tool body, the locking action being by less than a single relative turn between the lug and the lug receiving means.

The tool head has a portion of the head shaped such that it is capable of positive engagement with the tool body. The external shape of the head may be of any suitable shape for such positive engagement for example, in cross-section, square, rectangular, circular or any other well known shape, e.g.

VDI.. However, it is preferred that the tool head includes a frustoconical portion, the frus toconical portion being received within a cor responding tapered opening on the tool body to provide positive engagement between the tool head and the tool body.

The tool head and the tool body preferably have interconnecting keys such that on con nection the tool head and tool body are pro vided with positive locating means. The inter connecting keys are preferably in the form of castellated projections on either the tool head or the tool body which are receivable by corresponding depressions in the tool body or tool head, respectively. During the locating of the tool head to the tool body, the castellated projections interconnect to prevent rotational movement of the tool head with respect to the tool body.

The locking means between the tool head and tool body are preferably in the form of a locating peg which is substantially T-shaped to provide two lugs and lug receiving means having a radially elongated opening capable of receiving the two lugs, which are in the form of a T-shape. The two lugs pass through the radial elongated opening or slot. By turning the lugs by up to half a revolution, preferably 90 , these lock by turning preferably at right angles to the slot.

Although a substantially T-shaped arrangement is described, a single lug may be adopted. The single lug may pass through the radial opening of substantially 360 to provide locking action.

A particular feature of the present invention is that the locking action is quick and easy.

This is accomplished by turning the locking means, preferably by less than one turn in the case of a single lug, generally by no more than up to 1 80', more preferably by 90 , to lock the tool head and the tool body together.

Thus in the preferred embodiment using two lugs the locating action is preferably 90 turn.

The elongated opening or slot is preferably provided in a threaded internal screw, such that the opening is turned by the required amount of turn indicated above which can withdraw the screw causing a locking longitudinal pull on the locating lug drawing the tool head and tool body together.

It is preferred that the locating lug be attached to the tool head at the end of the frustoconical portion and that the radially elongated opening be positioned within the open jaw of the tool body. The invention will be particularly described with reference to this arrangement. However, it should be understood that it is possible to attach the locating lug to the tool body and the lug receiving means to the tool head.

The present invention will be further described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 shows the tool head of the present invention; Fig. 2 shows the tool head of Fig. 1 rotated through 90 in partial cross-section; Fig. 3 shows the tool body of the present invention; Fig. 4 is an end view of the tool body of the present invetion; Fig. 5 shows the tool head and tool body interconnected; and Fig. 6 is an arrangement showing the quickchange tool in use.

Figs. 1 and 2 show a tool head, generally designated 10. The tool head 10 can be adapted to provide any well known tool, such as a cut-off blade holder, a tapping head, a drill, a turning tool, or a boring bar. The tool head 10 has a pocket 12 for a cutting insert to be mounted therein. The tool head 10 can be of a generally cylindrical shape having a frustoconical portion 14 mounted on a main shank 15. The frustoconical portion 14 is positioned from the opposite side of the main shank 15 to the pocket 12. Although the frustoconical portion 14 is of a particular shape other shapes apart from frustoconical may be used such as cylindrical, square, or rectangular in cross-section.Attached to the frustoconical portion 14 is a locating peg 16, which is preferably of a T-shape to provide two lugs 18 and 19 connected via a shank 20 to a threaded portion 22 threaded into a bore 24 within the frustoconical portion 14.

This is shown in Fig. 2, the rotational position of Fig. 2 being at right angles to the position as shown in Fig. 1.

Referring now to Figs. 3 to 5, the tool head 10 is interconnected with the tool body 30, as particularly shown in Fig. 5. The tool body 30 is a generally cylindrical shape having an internal frustoconical bore 32, this corresponding to and interconnecting with the frustoconical portion 14 of the tool head 10. If an alternative shape apart from frustoconical is used then this would correspond to that shape. The important point about the shape of the internal bore 32 and the preferred frustoconical portion 14 is that they closely correspond and mate when in locked position to provide accurate and positive location of the two points. Within the tool body 30, at the opposing end to the frustoconical internal bore 32 is provided an internal thread 34 which receives an external thread of the locking device 36.The locking device 36 is preferably a hollow screw 38 having external thread 40 which mates with the internal thread 34 of the tool body 30 turned via a hexagonal drive 42. Although a hexagonal drive is described, the screw 38 may be operated by an electric motor having variable torque, or any other alternative rotational means.

At the end of the screw 38 opposite to the hexagonal drive 42 is a radially extending opening 44 capable of receiving and allowing therethrough the locating peg 16 of the tool head (more particularly shown in Fig. 5) in one position and locking it in position behind the edges 45 of the radially extending opening when turned by 904 and partially withdrawing the screw causing the tool head and tool body to lock together. At the end of the internal bore 32 is provided a disc 46 having thereon two drive dogs 48 capable of being received in castellated openings 50 in the tool head 10. The disc 46 is attached to the tool head 30 by means of set screws 50, 52, 54 and 56 passing through the disc into a flange 58 mounted on the end of the tool body 30.

To assembly the quick-change tool, a peg 16 is screwed into the frustoconical portion 14 of the tool head 10 until it is tight. The screw thread 22 is preferably a right-handed screw thread. The locking device 36 preferably comprises a screw 38 within the tool body 30. The screw 38 preferably has an external thread 40 which is left-handed i.e. an opposite handed thread to the thread 22 of the locating peg 16. The locking device 36 is screwed into the internal thread 34 of the tool body 30 until it is tight, providing the final locating position for the opening 44. The locating peg 16, which is preferably completely rounded prior to assembly with a narrower radius shank 20, i.e. without lugs 18.

On the final positioning of the opening 44 of the locking device 36 flats can be machined onto the locating peg on the head 18 to provide two lugs. Alternatively a single lug can be provided or even three lugs in a tricorn arrangement. Further flats are provided on the base of the threaded portion 22. providing the flats to form the lugs 18 at this stage allows the tool head and, in particular, the locking mechanism between the tool head and the tool body to be properly qualified. Once the locking mechanism is qualified, the disc 46 is attached to the flange 58 by means of the set screws 50, 52, 54 and 56. The final positioning of the set screws 50, 52, 54 and 56 is determined by the positioning of the drive dogs 48 within the castellated openings 50 of the tool head.The holes for the set screws can be drilled through the disc and into the flange 58, the holes in the flange 58 being threaded to receive the set screws 50, 52, 54 and 56.

The thread of the screw 38 is preferably left-handed if the thread of the locating peg 16 into the tool body 10 is right-handed such that any force applied to one will not cause the other to unlock. The thread of the screw 38 is chosen such that on approximately a quarter turn of the hexagonal drive 42 causes the screw 38 to retreat in turn causing the edges 45 to engage the lugs 18 as shown in Fig. 5 to lock it into position and to draw the head 10 and body 30 of the tool body together.

In operation, the frustoconical portion 14 of the tool head 10 having the locating peg 16 thereon is inserted into the internal bore 32 of the tool body 30 such that the peg passes through the opening 44 into the locking device 36. The hexagonal drive 42 is applied to the locking device 36 such that a turn of up to 180', but preferably about 90 , is applied to lock the lug 18 within the opening 44 as particularly shown in Fig. 5 causing the tool head 10 and tool body 30 to be drawn together. The locating peg 16 at this stage preferably abuts the semi flanged portion of the screw 38 providing the radially extending opening 44. To release the tool head 10. the hexagonal drive 42 is turned in the opposite direction until the lugs 18,19 line up with the opening 44 and can be withdrawn.

Fig. 6 shows an example of the quickchange tool in use. However, it can be used in many different ways in the same manner as conventional tools. The quick-change tool head 10 is mounted onto the tool body 30 by means of a locking drive lug 48 and by means of the locking device 36 engaging with the locating peg 16 (not shown in this figure but shown in Fig. 5) so that the hexagonal drive 42 is attached to the end of the tool body 30 to provide sufficient rotational motion to the locking device to lock or unlock it as required, i.e. up to 1 80', preferably about 90 . The tool body 30 is mounted on a tool block 62 and can be operated on a conventional lathe with a tail stock 64 and work driver 66 driving the workpiece 68 to which the cutting insert 70 is to be applied. When it is necessary to change the insert 70, the tool block 62 is withdrawn from the workpiece, the hexagonal drive 42 is rotated sufficiently to unlock the tool head 10 from the tool body 30, the tool head is withdrawn and a new tool head 10 is applied to the tool body 30. The locating peg 16 of the new tool head 10 passes through the semi flange portion 60 of the tool body 30 (as shown in Fig. 5) and the hexagonal drive 42 is locked by turning it by up to 1 80'. The tool block is then reapplied to the workpiece such that the insert 17 is again operational. It should be understood by this means a sufficient number of tool heads may be kept in reserve with inserts 70 properly indexed within the tool heads ready for use. If a tool requires changing this can be done quickly and easily as explained above.

Claims (8)

1. A machine tool having a tool head and a tool body which are capable of being quickly locked together or released from one another, the tool head being capable of positive nonrotational engagement with the tool body, the tool head and tool body having locking means therebetween comprising at least one locating lug and a locating lug receiving means capable of receiving the lug and locking it in position to draw the tool head and tool body together and to prevent the withdrawal of the tool head from the tool body, locking action being by a relative turn between the lug and the lug receiving means of less than 180 rotational movement.

2. A machine tool as claimed in claim 1, wherein there are at least two locating lugs receivable in a locating lug receiving means comprising a slot which allows the lugs to pass through and on rotation prevents the lugs from being withdrawn.

3. A machine tool as claimed in claim 2 wherein the lugs are attached to the tool head and the lug receiving means is within the tool body.

4. A machine tool as claimed in any one of the preceding claims, wherein the at least one locating lug is mounted on a peg attached to the tool head, the peg being substantially Tshaped to provide two lugs, the lug receiving means being a radially elongated slot mounted within the tool body.

5. A machine tool as claimed in any one of the preceding claims, wherein the tool head has a frustoconical portion which is receivable within a corresponding tapered jaw to provide positive non-rotational engagement between the tool head and the tool body.

6. A machine tool as claimed in any one of the preceding claims, wherein the tool head and tool body have interconnectable keys to provide positive non-rotational engagement between the tool head and the tool body.

7. A machine tool as claimed in claim 6, wherein the keys are external castellated projections mounted on the tool body receivable within corresponding depressions in the tool head when the tool body and the tool head are connected.

8. A machine tool as claimed in claim 1, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.