GB2408309A

GB2408309A - A resilient bush

Info

Publication number: GB2408309A
Application number: GB0423179A
Authority: GB
Inventors: Michael Griggs; Trevor Howard Johnson
Original assignee: Avon Vibration Management Systems Ltd
Current assignee: Avon Vibration Management Systems Ltd
Priority date: 2003-11-24
Filing date: 2004-10-19
Publication date: 2005-05-25
Anticipated expiration: 2024-10-19
Also published as: GB0327297D0; GB0423179D0; DE102004056265A1; GB2408309B

Abstract

A bush has a split inner sleeve 30 with an outer surface 35 which tapers from one end of the sleeve to the other, an outer tube, e.g. in the form of a sleeve 32 with a tapered inner surface 38, the taper of which matches the taper of the inner sleeve 30. The inner sleeve 30 fits into the outer sleeve 32 with the tapered surfaces 35, 38 abutting each other and the inner sleeve 30 is used to grip a rod 12. A resilient body 14 fits around the outer sleeve 32, and a bracket 20 secures the resilient body 14 to a chassis or subframe 16 of e.g. a vehicle. The inner and outer sleeves 30, 32 may have teeth 40, 42 to prevent the sleeves axially sliding in opposite directions. Preferably the sleeves 30, 32 have flanges at axially opposite ends 34, 36 so that the structure formed by the inner and outer sleeves 30, 32 is in the shape of a bobbin, and so resists axial movement of the resilient body 14.

Description

BUSH

The present invention relates to a bush. It is particularly, but not exclusively, concerned with a bush for mounting the anti-roll bar of a vehicle to the chassis or a sub-frame of that vehicle.

Existing bushes for connecting the anti-roll bar of vehicle to the chassis or sub-frame of that vehicle comprise a rubber body which is fitted around the anti roll bar. A bracket is then fitted around the body and is secured to the chassis or sub-frame e.g. by bolts.

Thus, with the bracket rigidly fixed to the chassis or sub-frame, the rubber body permits a degree of movement between the anti-roll bar and the chassis, but restricts excessive movement. However, such arrangements, although simple, have several defects. It is possible for the rubber body to slide along the axis of the anti-roll bar and, in extreme cases, it can slide out of the bracket and thus destroy the bush formed by the body and the bracket. There may also be torsional slippage.

Moreover, even when such slippage is very small, noise may be generated which is undesirable. Finally, since the rubber material is put under significant strains, there may be durability issues.

The present invention seeks to improve such bushes.

At its most general, the present invention proposes that a bush according to the invention has a split inner sleeve with an outer surface which tapers from one end of the sleeve to the other, an outer tube with a tapered inner surface, the taper of which matches the taper of the inner sleeve so that the inner sleeve fits into the tube with the tapered surfaces abutting each other, a resilient body of e.g. rubber into which the tube is received, and a bracket for securing the rubber body to e.g. a chassis or sub-frame.

If the inner sleeve and the tube are slid axially, the tapering of their respective surfaces causes the diameter of the inner sleeve to be reduced, which reduction is accommodated by the split in that inner sleeve, to cause the inner sleeve to grip to anti-roll bar. The outer tube forms a rigid hoop around the inner sleeve thereby resisting the forces tending to open that split inner sleeve. The outer surface of the tube also provides a surface to which the resilient body can be mounted. Thus, the inner sleeve and the tube provide a link between the rubber body and the anti-roll bar which firmly secures the resilient body to that anti-roll bar at a desired location.

should be noted that although the above description describes the mounting of the bush on an anti-roll bar, the present invention is applicable to other situations, in which a bush is to be mounted on a shaft, bar or rod. In the subsequent description, it is assumed that the bush is mounted on an anti-roll bar and the resilient body is of rubber for the sake of

simplicity of description.

Preferably, the inner sleeve and the tube have flanges at axially opposite ends so that the structure formed by the inner sleeve and the tube is in the shape of a bobbin which receives the rubber body. The flanges thus prevent or limit axial movement of the rubber body on the tube.

It has been mentioned that the inner sleeve is split so that its internal diameter may contract to secure it to the anti-roll bar. As a development of this, the inner sleeve may have more than one split (so that in fact it is formed of a plurality of sleeve parts) though such an arrangement may be more difficult to assemble.

Alternatively, a hinge may be provided in the inner sleeve remote from the split, to enable the inner sleeve to be opened and thus fitted around the anti-roll bar.

Although it is thought that the compression of the inner sleeve onto the anti-roll bar due to its interaction with the tube should be sufficient to secure it fixedly to the anti-roll bar, it is also possible for adhesive to be provided on the inner surface of the sleeve, such as pressure-sensitive adhesive or anaerobic adhesive, which adhesive is activated when the inner sleeve is pressed onto the anti-roll bar thereby providing a stronger bond.

The tube may be a single component, forming an outer sleeve. That sleeve may be continuous, or may be hinged in order to enable it to be opened out to fit around the inner sleeve. However, if that is done it is necessary for the two parts of the outer sleeve to be locked together when it is fitted in place so that it forms a hoop of fixed diameter as has been mentioned above. In another alternative, the tube may be formed by two parts, an outer split sleeve which has the tapered surface matching the inner sleeve, and a ring which fits around the outer sleeve to provide a fixed outer diameter.

Again, that ring may be split to enable it to be fitted in place, provided the two parts may then be locked together rigidly. Moreover, in such an arrangement the outer sleeve may itself be hingedly split.

When the inner sleeve is forced into the tube to cause it to contract onto the anti-roll bar, it is important that it cannot slide axially in the opposite direction, which would release the bond. Therefore, it may be necessary to provide teeth on the tapered surfaces, which teeth engage to prevent such incorrect sliding. In addition, or alternatively, the inner sleeve and the tube may be secured together by bayonet connections or by other fixings when the inner sleeve is in the correct position. For example, projections on the tube may extend into openings in the flange of the inner sleeve (where such a flange is provided) and may be adhered thereto.

In yet another alternative, the tube may be formed by two parts which are separable, which lock together by bayonet or other fittings to provide a rigid hoop around the inner sleeve.

Another advantage of the arrangements discussed above, apart from better fixing of the rubber body to the anti-roll bar, is that it is possible to use many of the same components, even when the size of the anti-roll bar differs. For example, if a range of inner sleeves is provided, with different inner diameters but a common outer diameter, these can then be used with a standard sleeve and rubber body. It is common for a range of vehicles to have roll-bars of different diameters, and existing arrangements need differently sized bushes for each.

While the inner sleeve is securely fixed to the anti-roll bar by its interaction with the tube, it is possible for there to be a degree of movement between the tube and the rubber body, e.g. to permit a degree of rotation. Excessive axial movement of the body relative to the tube is prevented by the flanges where provided.

Moreover, the rubber body may itself, be split in order to enable it to be fitted around the tube, and its outer surface may be shaped to as to conform to the bracket IS which is to attach it to e.g. the chassis.

Embodiments of the present invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a geometric view of a bush according to the present invention mounted between an anti-roll bar and a chassis part; Fig. 2 is a sectional perspective view of the bush of Fig. 1; Fig. 3 is an axial sectional view of the bush of Fig. 1; Fig. 4 is a view of an inner sleeve of the bush of Fig. 1; S Fig. 5 is a perspective view of an outer sleeve of the bush of Fig. 1; Fig. 6 is an end view of the outer sleeve of Fig. 6; Fig. 7 is a transverse sectional view of the bush of Fig. 1; Fig. 8 is an end view of a modified outer sleeve for the embodiment of Fig. 1; Fig. 9 illustrates a further modification of the outer sleeve; Fig. 10 shows a corresponding modification of the inner sleeve; Fig. 11 is a perspective view of the outer and inner sleeves of Figs. 9 and 10, when joined together) Fig. 12 is an end view of the arrangement shown in Fig. 11; Fig. 13 is yet another modification of the outer sleeve; Fig. 14 is a perspective view showing the mounting together of the inner sleeve of Fig. 10 and the outer sleeve of Fig. 13; Fig. 15 shows a rubber body for use with the mount of Fig. 1; Fig. 16 is an inner sleeve for use with a second embodiment of the present invention; Fig. 17 is an outer sleeve for use with the second embodiment; Fig. 18 is a ring for use with the second embodiment; Fig. 19 is an axial sectional view of a bush according to the second embodiment; Fig. 20 is a transverse sectional view of the bush of the second embodiment; Fig. 21 is a perspective view, partially in section, of the bush of this embodiment.

The first embodiment of the invention will now be described with reference to Figs. 1 - 15.

Fig. 1 illustrates generally the bush of the first embodiment of the present invention. It comprises a bobbin 10 which fits around an antiroll bar 12 and is itself contained within a rubber body 14. The rubber body 14 is then secured to e.g. a chassis part 16 by a bracket 18 which compresses the rubber body 14 sufficiently to provide the desired resilient characteristics. Bracket 18 has a curved part 20 which fits around the rubber body 14, and flanges 22, 24 with respective bores 26 into which a bolt may be fitted to secure the flanges 22, 24 to the chassis part 16. Thus, the bush links the anti-roll bar 12 to the chassis part 16 with the rubber body 14 permitting a degree of movement there between, but preventing excessive movement.

The structure of the bush shown in Fig. 1 is illustrated more clearly by the sectional views of Figs. 2 and 3. Those Figures shows that the bobbin 10 lO comprises an inner sleeve 30 and an outer sleeve 32 forming a tube around the inner sleeve. The inner sleeve is split and is located sequentially about the anti- roll bar 12. The outer sleeve 32 is then concentric with the inner sleeve 30, and the rubber body 14 then fits around the outer sleeve 32.

The inner sleeve 30 has an end flange 34 and an elongate part 33 extending along the anti-roll bar 12.

The outer surface 35 of that elongate part 33 is tapered so that it forms a frusto-cone. Similarly, the outer sleeve 32 has an end flange 36 and an inner surface 38, the tapering of which matches the tapering of the outer surface 35 of the inner sleeve 30. Thus, if the inner and outer sleeves 30, 32 are slid axially, in a direction which brings their flanges towards each other, the action of the two tapered surfaces 35, 38 is such as to exert a compressive force on the inner sleeve 30, the diameter of which thus tends to reduce. It will be recalled that the inner sleeve 30 is split to permit this reduction. Thus, the inner sleeve 30 is compressed onto the anti-roll bar 12, thereby fixing the bobbin 10 to that anti-roll bar 12.

The rubber body 14 then fits on the outer sleeve 32 and is held in place by the flanges 34, 36. Axial movement of the rubber body 14 relative to the bobbin 10 is thereby prevented.

Although not illustrated in Figs. 2 and 3, adhesive may be provided on the inner surface of the inner sleeve 30, where it contacts the anti-roll bar 12. That adhesive may be contact- sensitive adhesive or anaerobic adhesive which is activated when the inner sleeve is compressed onto the anti-roll bar 12 to bond the inner sleeve 30 to the anti-roll bar 12. Teeth on the inner bore of the inner sleeve 30 or a thin bonded polymer membrane may also or alternatively be used to increase the grip of the inner sleeve on the anti-roll bar.

Moreover, as can be seen from Fig. 3, teeth 40, 42, are provided on the inner and outer sleeves 30, 32 along the tapered surfaces 35, 38. Those teeth engage when the inner sleeve 30 is forced into the outer sleeve 32, thereby resisting movement of the inner sleeve axially relative to the outer sleeve in a way which would separate the flanges 34, 36, to prevent the bobbin 10 becoming separated.

The inner sleeve 30 is illustrated in more detail in Fig. 4. Fig. 4 shows how that inner sleeve is split to provide an opening split 50. Moreover, the inner sleeve preferably has a hinge 52 diametrically opposite the split 50, to allow the split 50 to be opened. It is desirable that the split 50 can be opened sufficiently enable the anti-roll bar 12 to pass therethrough, before the inner sleeve 30 is closed, at least partially, to fit around the anti-roll bar. This is more convenient than having to slide the inner sleeve 30 along the anti-roll bar to the position in to which it is to be located.

Alternatively the sleeve 30 may be moulded in its open state and closed onto the anti-roll bar 12 if this is easier for manufacture.

The same is true of the outer sleeve. Thus, as illustrated in Fig. 5, the outer sleeve 32 may have a slit 54 and a hinge 56 diametrically opposite the slit 54 and a hinge 56 diametrically opposite the slit 54, to allow the outer sleeve 32 to be opened to be fitted around the anti-roll bar 12 with the anti-roll bar passing through the slit 54 before the outer sleeve 32 is closed. However, unlike the inner sleeve, the diameter of the outer sleeve 32 must be rigidly fixed. Therefore, latches 58, 60 are provided on the edges of the outer sleeve 32 along the slit 59, which latches 58, 60 engage when the slit 54 is closed and prevent subsequent opening of the slit 54. For manufacture of the outer sleeve 32 it may again be easier to mould it in its open state and close it to engage the latches 58,60.

This locking of the hinged outer sleeve can be seen in Fig. 7 in which the latches 58, 60 are engaged and thus close the loop of the outer sleeve 32. The outer sleeve thus forms a hoop or tube around the split inner sleeve 30.

Many modifications of the first embodiment are possible. For example, the inner sleeve may have multiple slits, so that it is formed by several sleeve parts. However, such an arrangement is not preferred because it makes assembly more difficult, since the sleeve parts have to be held in position around the anti- roll bar 12 until they are received within the outer sleeve 32.

Fig. 8 illustrates a modification of the outer sleeve, compared to the arrangement shown in Figs 5 and 6. In Fig. 8, the outer sleeve 32 comprises two sleeve parts 70, 72 each forming approximately a semi-circle, with the edges of those sleeve parts, 70, 72 having latches 74, 76 thereon, with the latches 74 and 76 engaging when the two sleeve part 70, 72 are fitted together (e.g. by axial sliding of one relative to the other) to lock the two sleeve part 70, 72 together and thus form a rigid hoop or tube into which the inner sleeve can be inserted. Although not visible in Fig. 8, because it is a end view on the flange outer face, the interior 78 of the outer sleeve will be tapered to conform to the taper of the inner sleeve 30 in a way similar to that already described.

As has been mentioned, teeth 40, 42 may be provided in order to lock the inner and outer sleeves 30, 32 together. Another way of securing together the inner and outer sleeve is illustrated in Figs 9 to 12. As shown in Fig. 9, the outer sleeve 32 has projections 80 thereon which project axially outwardly from the end of the outer sleeve 32 remote from flange 36. Also, as illustrated in Fig. lo, the inner sleeve 30 has a flange 34 with openings 82 therein which match the projections 80.

Thus, when the inner sleeve is fitted into the outer sleeve 32, the projections 80 project into the openings 82 from the arrangements shown in Fig. 11 and 12. The projections 80 may then be bonded to the flange 34 by adhesive, by heat sealing, or by melting them sufficiently that they flow over adjacent surface of the flange 34 and thus cannot subsequently be slid out of the holes 82.

A further modification is illustrated in Figs 13 and 14. In this arrangement, there are projections 90, 91, 92, 93 on the outer sleeve 32 at the end opposite to the flange 36 each projection defining a latch which latches over the flange 34 of the inner sleeve 30 as illustrated in Fig. 14. A potential problem with such an arrangement is that if the length of the projections 90 to 93 is not correct, there may be insufficient clamping of the inner sleeve to the anti-roll bar. However, this problem can be solved, or at least ameliorated, by making the projections 90 to 93 of different lengths. Thus, the projections 90, 92 may be have one length and the projections 91, 93 have a shorter length. Then, when the inner and outer sleeves are moved axially together, to reduce the spacing between the flanges 34, 36, the latches formed by projections 90, 92 will engage first.

If, at that point, the inner sleeve is sufficiently secured to the antiroll bar, then no further movement is needed and the latching of projections 91, 93 does not occur. If, however, the bonding is insufficient, further axial movement will trigger the latches of the projections 91, 93 thus the projections 90 to 93 providing a range of possible securing positions for the inner and outer sleeves 30, 32. This may be useful, e.g. if the sleeves are to be used with different sized anti- roll bars. Clearly, it is possible to provide multiple staged interconnection, by providing more projections of varying lengths.

As has been mentioned previously, the splitting of the inner sleeve 30, and possibly splitting of the outer sleeve 32, is desirable so that they do not have to be slid along the anti-roll bar. The same is true of the rubber body 14, and thus as illustrated in Fig. 15 that rubber body 14 may have a slit 98 to enable the rubber body to be fitted around the outer sleeve 32 prior to the fitting of the bracket 18.

In the first embodiment of the present invention, described with reference to Figs 1 to 15, the bobbin 10 was formed by two components, being the inner and outer sleeves 30, 32. The outer sleeve formed a tube into which the inner sleeve was fitted, that tube being of fixed diameter when the inner sleeve was positioned within it. In the second embodiment, illustrated with reference to Fig. 1 and Figs 16 to 21, the bobbin 10 of Fig. 1 has three components. There is a split inner sleeve 100 illustrated in Fig. 16 a split outer sleeve 102 illustrated in Fig. 17, and a ring 103 illustrated in Fig. 18. The other components of this second embodiment may be the same as those shown in Fig. 1, and will therefore not be described in further detail. Where they are illustrated, the same reference numerals will be used.

Thus, as illustrated in Fig. 16, the inner sleeve has a slit 106 along its length, and a tapered surface 108. A flange 110 is provided one end of the inner sleeve 100. The outer sleeve 102 also has a slit 112 along its length, as illustrated in Fig. 17, has a tapered inner surface 114 conforming to the tapered outer surface 108 of the inner sleeve 100, and has a flange 116 at each end. If the inner sleeve 100 was pushed into the outer sleeve 102, then although there may be some closing of the slit 106, there may also be some opening of the slit 102. This would not provide suitable fixing of the inner sleeve 100 to the anti- roll bar. Therefore, the bobbin 10 also includes a ring 104 which fits around the outer sleeve 102 to provide a hoop strength to resist opening of the slit 112. Thus, in this embodiment, the bobbin 10 has a three-part structure. The outer surface 118 of the outer sleeve 102, and the inner surface 120 of the ring 104 may be cylindrical. Fig. 18 also shows that the ring 104 may have a projection 122 on its inner surface, which projection is received in the slits 106, ll2 of the inner and outer sleeves 100, 102. The purpose of this is to act as a partial closure of those slits 106, 112. However, the circumferential extent of that projection 122 should not too large, as it may otherwise prevent closing of the slit 106 as it clamps around the anti-roll bar. Fig. 19 thus illustrates the bobbin 10 of the second embodiment when fitted on the anti-roll bar 12.

Fig. 19 shows the three-component bobbin mounted on the anti-roll bar 12. The tapered surfaces 108, 114 of the inner and outer sleeves 100,102 engage so as to clamp the inner sleeve 100 into the anti-roll bar 12 in a similar manner to the inner sleeve 30 of the first embodiment. Similarly, the sectional view of Fig. 20 shows how the projection 112 fits into the slits 106, 112 of the inner and outer sleeves 100, 102. Finally, the partially sectional view of Fig. 21 shows the appearance of the bobbin of this second embodiment on the anti-roll bar 12, the bobbin being a multilayered arrangement formed by the inner and outer sleeves and the ring 100, 102, 104. Note that the rubber body is not illustrated in Figs 19 and 21 for the sake of clarity.

One disadvantage of this second embodiment is that if the outer ring is continuous, then it needs to be slid along the anti-roll bar. Moreover, that must be done before the inner and outer sleeves are positioned on the anti-roll bar so that it can fit between the flanges 100, 116. It would be possible to have the ring 104 split, in a similar way to the outer sleeve of Fig. 5 or Fig. 8, but that further increases the complexity of the second embodiment.

In the above discussion of the first and second embodiments, it has been assumed that the bush of the embodiments is mounted on a anti-roll bar 12. However, it can be seen that the bushes of the first and second embodiments may be mounted to other rods, bars or shafts which are to be secured to a body to provide limited movement of the rod, bar or shaft relative to the body.

In either embodiment, it is possible to adapt to different sized antiroll bars by varying the inner diameter of the inner sleeve 30, 100. It would be possible, for example, to provide a plurality of inner sleeves of different inner diameter to fit different anti-roll bars, with a common outer sleeve and (possibly) ring 104.

The materials of the inner and outer sleeves and the rubber body will depend on the particular application.

In the simplest case, the rubber body maybe of natural rubber, with the inner and outer sleeves of nylon or similar plastics material. The outer surface of the outer sleeve 32, in the first embodiment, or the ring 104 in the second embodiment may be textured to grip the rubber. Alternatively, the rubber body 14 may be directly moulded onto the bobbin. It may then be desirable to form the bobbin components (the outer sleeve and possibly the ring 104) of a plastics material such as Vestoran which has a nature such as not to require a chemical bonding agent to secure it to the rubber material. Yet another possibility is to provide a lubricated or PTFE surfaces as either the rubber body 14, the outer sleeve 32 or the ring 104 to provide a degree of slippage between the rubber body and the bobbin. This could be used where slip is of advantage, or is required to eliminate noise.

Claims

CLAIMS: l. A bush comprising: a split inner sleeve having an outer

surface, the diameter of which decreases along the axial length of the sleeve; an outer tube into which the sleeve is received, the tube having an inner surface, the diameter of which increases along the axial length of tube, the increase of the diameter of the inner surface of the tube matching to decrease in diameter of the outer surface of the inner sleeve; a resilient body around the tube; and a bracket into which the resilient body is received.
2. A bush according to claim l, wherein the inner sleeve has a flange at one axial end and the tube has a flange at the opposite axial end, whereby the flanges limit axial movement of the resilient body.
3. A bush according to claim l and claim 2, wherein the inner sleeve has multiple splits therein.
4. A bush according to claim 2 and claim 3, wherein the inner sleeve comprises a plurality of sleeve parts hingedly connected together.
5. A bush according to any one of the preceding claims, wherein the tube is a circumferentially unbroken outer sleeve.
6. A bush according to any of claims 1 to 4, wherein the tube comprises a plurality of parts connected together, to form a sleeve.
7. A bush according to claim 6, wherein at least some of said parts of said sleeves are hingedly connected together.
8. A bush according to any one of claims 1 to 4, wherein the tube comprises an outer split sleeve and a ring around said outer split sleeve.
9. A bush according to any one of the preceding claims wherein teeth are provided on the inner surface of the tube and the outer surface of the inner sleeve.
10. A bush substantially as herein described with reference to and as illustrated in Figs 1 to 15 as Figs 16 to 21 of the accompanying drawings.
11. A kit of parts comprising a plurality of split inner sleeves, each having an outer surface, the diameter of which decreases along the axial length of the sleeve; an outer tube into which each of said sleeves is receivable, the outer tube having an inner surface, the diameter of which increases along the axial:Lenyth of the tube, the increase of the diameter of the inner surface of the tube matching the decrease in diameter of the ouster surface of each said inner sleeve; a resilient body mountable around the tube; and a bracket into which the resilient body is receivable; wherein said plurality of inner sleeves have different inner diameters, and the decrease in diameter of the outer surface of all the inner sleeves is the same. 2S

11. A kit of parts comprising a plurality of split inner sleeves, each having an outer surface, the diameter of which decreases along the axial length of the sleeve; an outer tube into which each of said sleeves is receivable, the outer tube having an inner surface, the diameter of which increases along the axial length of the tube, the increase of the diameter of the inner surface of the tube matching the decrease in diameter of the outer surface of each said inner sleeve; a resilient body mountable around the tube; and a bracket into which the resilient body is receivable; wherein said plurality of inner sleeves have different inner diameters.

Amendments to the claims have been filed as follows CLAIMS: l. A bush comprising: a split inner sleeve having an outer surface, the diameter of which decreases along the axial length of the sleeve; an outer tube into which the sleeve is received, the tube having an inner surface, the diameter of which increases along the axial length of tube, the increase of the diameter of the inner surface of the tube ma'.ching to decrease in diameter of the outer surface of the inner sleeve; a resilient body around the tubed and a bracket into which the resilient body is received.

2. A bush according to claim l, wherein the inner sleeve has a flange at one axial end and the tube has a flange at the opposite axial end, whereby the flanges limit axial movement of the resilient body.

3. A bush according to claim l and claim 2, wherein the inner sleeve has multiple splits therein.

4. A bush according to claim 2 and claim 3, wherein the inner sleeve comprises a plurality of sleeve parts hingedly connected together.

5. A bush according to any one of the preceding claims, wherein the tube is a circumferentially unbroken outer sleeve.

6. A bush according to any of claims I to 4, wherein the tube comprises a plurality of parts connected together, to form a sleeve.

7. A bush according to claim 6, wherein at least some of said parts of said sleeves are hingedly connected together.

8. A bush according to any one of claims 1 to 4, wherein the tube comprises an outer split sleeve and a ring around said outer split sleeve.

9. A bush according to any one of the preceding claims wherein teeth are provided on the inner surface of the tube and the outer surface of the inner sleeve.

lo. A bush substantially as lierein described with reference to and as illustrated in Figs 1 to 15 or Figs 16 to 21 of the accompanying drawings.

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