GB2101018A - Improvements in or relating to drive assemblies - Google Patents

Abstract

A drive assembly 10 for a boring bar 40 comprises a drive unit (tool body 11) and a driven unit (tool holder and slide 12), the units 11, 12 being urged together by clamping shoes 29 located by aligned slots 18 and sockets 27 formed in units 11, 12 respectively. Each shoe 29 is formed with a circumferential slot 30 on a circular portion 31 and a lateral slot 32 on a transverse portion 33. Bores 28 in unit 11 locate screws 34 having reduced-section ends 35 which are received in the circumferential slots 30 of the shoes 29 whereby the shoes are arrested in the unit 12. Bores 19 locate screws 36 having tapered lower ends 36a which are received in the lateral slots 32 of the shoes 29. As each screw 36 is rotated inwardly, the tapered bottom end 36a thereof engages inclined wedge face 37 on the associated clamping shoe 29 so that it is urged towards the left (as viewed in Figure 1), thus bringing the end faces 16, 26 of units 11, 12 into firm engagement with each other. <IMAGE>

Description

SPECIFICATION Improvements in or relating to drive assemblies This invention relates to drive assemblies.

According to the invention, a drive assembly comprising a drive unit and a driven unit has wedge means for urging the units together so as to form a drive connection.

The wedge means may comprise a clamp element engageable with one of the units and having an inclined wedge face engageable with a member mounted in the other unit and operable so as to move said clamp element and form the drive connection.

The operable member may comprise a screw having a tapered and engageable with said inclined face.

The clamp element may comprise a slot cooperable with a further screw mounted in said one unit.

Said one unit may be the driven unit.

The assembly may include means for carrying a boring bar.

Means may be provided for adjusting the mounting means relative to movement between the drive unit and the driven unit. The adjusting means may comprise an adjusting screw engaged with a component supported by one of said units.

The drive and driven units may be inter-connected by key means.

The invention may be performed in various ways.

One specific embodiment with modifications will now be described, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is a side view, partly in section, of a drive assembly for a boring tool, comprising a tool body and a tool holder/slide, the section being on the line A-A of Figure 3, Figure 2 is an end view of the tool body, Figure 3 is a side view of the tool holder/slide with part omitted, Figure 4 is a side view of a screw and a clamping shoe, Figure 5 is a front view of the clamping shoe, Figure 6 is a side view of an adjusting screw, Figure 7 is a side view of a keeper plate, Figure 8 is a side view of one modified drive assembly, Figure 9 is a side view of another modified drive assembly, and Figures 10 and 11 are sections, taken on lines X-X and XI-Xl of Figures 9 and 10 respectively.

In the figures, like reference numerals referto like components.

With reference to Figures 1 to 7, a boring bar drive assembly 10 comprises a drive unit (tool body 11) for rotation by a machine, (not shown), and a driven unit (tool holder and slide 12) for carrying a boaring bar 40.

The tool body 11 comprises body structure 13 formed with an International taper 13a. The tool body 11 is held in a boring machine. The end face 16 ofthetool body 11 remote from the taper 13a is provided with central transverse slot 17 and laterally spaced side slots 18 disposed substantially parallel to slot 17. Screw-threaded bores 19 extend laterally from the slots 18 to the periphery of the tool body 11.

Opposed side faces of the central slot 17 are formed with keyway-like slots 22.

In the assembled condition illustrated by Figure 1, the slots 22 confront cooperating key slots 23 formed in the side faces of a driving tenon 24. The tenon 24 extends from the tool holder 12 into the central slot 17 so that the units 11 and 12 are inter-connected in a slidable relationship. Keeper strips 25 are removably received by the aligned slots 22, 23. With reference to Figure 2, the keeper strips 25 are prevented from emerging out of the right hand ends of slots 22 by spring pins 61 of tubular form. The keeper strips 25 serve as key means which interconnect the units 11 and 12.

As illustrated in Figure 1, the tenon 24 is integral with the tool holder/slide 12. Alternatively however, it may be made from separate components demountably attached to the holder/slide 12.

The tool holder/slide 12 has an end face 26 confronting face 16 of the tool body 11 and is formed with laterally spaced sockets 27 confronting slots 18 of the holder/slide. Screw-threaded lateral bores 28 extend inwardly from the periphery of the tool holder/slide 12 towards the centre thereof, so as to communicate with the sockets 27.

Clamping shoes 29 are located by the aligned slots 18 and sockets 27. Each shoe 29 is formed with a circumferential groove or slot 30 on a circular portion 31 and a lateral slot 32 on a transverse portion 33. (See Figures 4 and 5). Each lateral bore 28 locates an Allen screw 34 having a reduced-section and 35 which is received in the circumferential slot 30 of the associated shoe 29 whereby the shoe may be arrested in the tool holder/slide 12. Each bore 19 locates an Allen screw 36 having a tapered lower end 36a which is received in the lateral slot 32 of the associated shoe 29. As shown in Figure 4, the slot 32 has a flat side face 37 which inclines outwardly away from the slot.As each screw 36 is rotated, the tapered bottom and 36a thereof enegages the inclined wedge face 37 whereby the associated clamping shoe 29 is urged towards the left (as viewed in Figure 1), thus bringing the end faces 16, 26 of tool body 1 1 and tool holder/slide 12 into firm engagement with each other. The arrangement provides wedge means for urging the units 11 and 12 together so as to form a drive connection.

Should the screws 34, 36 fail for any reason, the tool holder/slide 12 and the tool body 11 are prevented from separating by the keeper strips 25.

The clamping shoe illustrated in Figures 4 and 5 is actually slightly different from those shown by Figure 1.

The tool holder/slide 12 is provided with a socket 39 for removably receiving the boring bar 40. The usual sleeves may be fitted in the socket 39 to accommodate employment of different sizes of boring bars. The boring bar 40 is provided with the usual cutting tip. (Not shown). The boring bar40 is secured in the socket 39 by Allen screws 63.

The tenon 24 of the tool holder/slide 12 is provided with a central socket 41 which receives a block 42 formed with a hole 43 extending laterally therethrough. The hole 43 is internally threaded with a micrometer screw-thread. With reference to Figure 6, the hole 43 locates a micrometer adjusting screw 44. The screw 44 has a waisted head 44a formed with a socket 44b for receiving an Allen key, whereby the screw 44 can be rotated. A side face 60 of the tool body 11 is recessed to receive a keeper plate 45, (see also Figure 7), which is removably attached to the tool body by screws 46. The keeper plate 45 has a laterally extending slot 47 which engages the waisted portion of the screw head 44a. An aperture 50 (Figure 2) extends laterally from the end of the slot 17 remote from side face 60, to the periphery of the tool body 11.The aperture 50 allows free passage of the adjusting screw 44 as it rotates within the slot 17.

Rotation of the adjusting screw 44 within the block 42 causes relative sliding motion between the tool body 11 and tool holder/slide 12 whereby the boring bar 40 is displaced sideways relative to the axis of rotation of tool body 11. Thus the bar 40 is displaced so as to take another, or further cuts.

Before operating screw 44 however, the clamping screws 36 must first be slackened so as to release the clamping shoes 29 and thus allow the abovementioned relative movement between the units 11 and 12. After adjustment of the screw 44, the screws 36 are retightened so that the clamping shoes 29 cause the drive unit 11 and driven unit 12 to be held or locked securely together.

The modified drive assembly 110 illustrated by Figure 8 comprises a modified drive unit (tool body 111) and a driven unit (tool holder and slide 112).

The modified drive assembly 110 has the following features:1. Each of the pair of simplified clamping shoes 129 used is formed with a concavity 130 of conical form, cooperable with a similarly-shaped end of an Allen screw 134, whereby one end of the shoe 129 is arrested in the tool holder/slide 112.

The other end of each shoe 129 is formed with a laterally-extending slot 132 defining an inclined face 137. Face 137 is inclined at about 45 to the longitudinal axis 180 of the tool body 111 in which it is located.

Clamping strips 181 are disposed between each inclined face 137 and the bottom ends 136a of Allen screws 136. As each screw 136 is rotated, the bottom end 136a thereof engages the associated clamping strip 181 whereby the clamping shoes 129 are urged towards the left (as viewed in the drawing), thus bringing the end faces 116,126 of tool body 111 and tool holder/slide 112 into firm engagement with each other.

The employment of clamping strips 181 avoids marking the shoes 129. Disposing the screws 136 at an angle to shoes 129 reduces the effort needed to achieve locking.

2. The tenon 124 is not integral with the holder/slide 112 but instead comprises a separate component.

The modified drive assembly 210 of Figures 9, 10 and 11 has the following features:1. Each of the pair of clamping shoes 229 used is formed with a socket 230, cooperable with the spigot end of an Allen screw 234, whereby one end of the shoe 229 is arrested in the tool holder/slide 212.

The other end of each shoe 229 is formed with a laterally-extending slot 232 defining an inclined face 237. Face 237 is inclined at about 45"to the longitudinal axis 280 of the tool body 211 in which it is located.

Locking strips 281 are disposed between each inclined face 237 and the bottom ends 236a of Allen screws 236. As each screw 236 is rotated, the bottom end 236a thereof engages the associated clamping strip 281 whereby the clamping shoes 229 are urged towards the taper end of the tool body 211, thus bringing the end faces 216,226 of tool body 211 and tool holder/slide 212 into firm engagement with each other.

As in the case of the Figure 8 modification, the employment of clamping strips 281 avoids marking the shoes 229, and disposing the screws 236 at an angle to shoes 229 reduces the effort needed to achieve locking.

2. The tenon 224 is not integral with the holder/slide 212 but instead comprises a separate component held in place by a lock nut 300.

3. The taper 213a is a separate component, secured to tool body 211 by bolts 301 (Figure 11) and located in place by a dowel 302 and interfitting spigot and socket 303/304 (Figure 10).

The drive clamping assemblies are not limited to use with boring tools as described. They can be used to clamp other assemblies of driving and driven units.

Each of the arrangements provides a compact clamping assembly wherein the moving parts are hidden from view.

Each of the described clamping shoe connections has a wedge action which is superior to, for example, a dovetail connection. A dovetail connection requires very accurate machining of the interfitting parts.

Claims (14)

1. A drive assembly comprising a drive unit and a driven unit has wedge means for urging the units together so as to form a drive connection.

2. An assembly as claimed in Claim 1, wherein the wedge means comprise a clamp element engageable with one of the units and having an inclined wedge face engageable with a member mounted in the other unit and operable so as to move said clamp element and form the drive connection.

3. An assembly as claimed in Claim 2, wherein the operable member comprises a screw having a tapered end engageable with said inclined face.

4. An assembly as claimed in Claim 2 or 3, wherein the clamp element comprises a slot cooperable with a further screw mounted in said one unit.

5. An assembly as claimed in any one of Claims 1 to 4, provided with means for carrying a boring bar.

6. An assembly as claimed in Claim 5, provided with means for adjusting the mounting means.

7. An assembly as claimed in Claim 6, wherein the adjusting means comprise an adjusting screw engaged in a component supported by one of said units.

8. An assembly as claimed in any one of Claims 1 to 7, provided with key means for interconnecting the drive and driven units.

9 A boring bar drive assembly comprising a drive unit for rotation by a machine and a driven unit for carrying a boring bar, wedge means for urging tha unitstogether so as to form a drive connection, and means whereby the boring bar may be displaced sideways relative to the axis of rotation of the drive unit.

TO An assembly as claimed in Claim 9, wherein the drive unit and the driven unit are interconnected in slidable relationship.

11. An assembly as claimed in Claim 10, wherein means are provided whereby the drive unit and driven unit are locked together.

12. A drive assembly substantially as hereinbefore described with reference to Figures 1 to 7 of the accompanying drawings.

13. A drive assembly substantially as hereinbefore described with reference to Figure 8 of the accompanying drawings.

14. A drive assembly substantially as hereinbefore described with reference to Figures 9, 10 and 11 of the accompanying drawings.