GB2557256A

GB2557256A - A collapsible non adjustable steering column assembly

Info

Publication number: GB2557256A
Application number: GB1620467.9A
Authority: GB
Inventors: Davies Niclas; George Kingston-Jones Harry
Original assignee: TRW Ltd
Current assignee: TRW Ltd
Priority date: 2016-12-02
Filing date: 2016-12-02
Publication date: 2018-06-20
Anticipated expiration: 2036-12-02
Also published as: GB2557256B; GB201620467D0; CN108146491A; CN108146491B

Abstract

A collapsible, non-adjustable steering column assembly 100 for a vehicle comprises a support bracket 102 for securing to a fixed part of the vehicle, the support bracket 102 including an integrally formed guiding portion 114; and a tubular shroud portion 104 which supports a steering column shaft 106 and, in normal use, is fixed relative to, and at least partially within, the guiding portion 114. In the event of a crash, the tubular shroud portion 104 moves relative to, and is guided axially and controlled rotationally relative to a longitudinal axis of the tubular shroud portion 104 by the support bracket 102. In another embodiment the tubular shroud portion 104 may have a polygonal cross section and the support bracket 102 is integrally formed as one part.

Description

(71) Applicant(s):

(56) Documents Cited:

GB 1295748 A US 2836079 A

GB 1123760 A US 20040000782 A1

TRW Limited (Incorporated in the United Kingdom)

Stratford Road, SOLIHULL, West Midlands, B90 4AX, United Kingdom (58) Field of Search:

INT CL B62D

Other: WPI,EPODOC, Internet, Fulltext (72) Inventor(s):

Niclas Davies

Harry George Kingston-Jones (74) Agent and/or Address for Service:

Barker Brettell LLP

100 Hagley Road, Edgbaston, BIRMINGHAM, B16 8QQ, United Kingdom (54) Title of the Invention: A collapsible non adjustable steering column assembly

Abstract Title: Support bracket and guiding portion for a non-adjustable collapsible steering column (57) A collapsible, non-adjustable steering column assembly 100 for a vehicle comprises a support bracket 102 for securing to a fixed part of the vehicle, the support bracket 102 including an integrally formed guiding portion 114; and a tubular shroud portion 104 which supports a steering column shaft 106 and, in normal use, is fixed relative to, and at least partially within, the guiding portion 114. In the event of a crash, the tubular shroud portion 104 moves relative to, and is guided axially and controlled rotationally relative to a longitudinal axis of the tubular shroud portion 104 by the support bracket 102. In another embodiment the tubular shroud portion 104 may have a polygonal cross section and the support bracket 102 is integrally formed as one part.

Figure 1

102 108

116

100

108

106

136

134

138

112 ........'

1/3

Figure 1

102

108

116

100

112

106

136

134

138

2/3

114

3/3

Figure 5

A COLLAPSIBLE, NON-ADJUSTABLE STEERING COLUMN ASSEMBLY

The present invention relates to improvements in collapsible, non-adjustable steering column assemblies.

Many types of steering column assemblies are known. Although adjustable steering column assemblies are commonplace, in some circumstances where such things as weight, cost and packaging pose constraints then it is still desirable to utilise a nonadjustable assembly. However, in order that such an assembly may have acceptable characteristics in a collision, it is necessary to provide even non-adjustable steering column assemblies with the ability to move in response to an impact from the driver’s body, to prevent or limit injury to the driver.

Known non-adjustable steering column assemblies comprise a support bracket and a shroud which houses the steering column shaft. The shaft is connected at one end to a handwheel and at the other to the wheels of the vehicle, perhaps via a power-steering system. The support bracket is attached to a fixed part of the vehicle and supports the shroud, such that the steering column shaft is in the desired position.

In these known assemblies, the support bracket is configured such that it may break away from the fixed part of the vehicle. By doing so, the shroud or column tube of the column assembly is allowed to collapse or deform such that, when impacted by the driver during the collision, the shroud or column tube and support bracket move with driver’s body thus limiting potential injury to the driver. However, the applicant appreciates that such an assembly may not be suitable for all applications.

In accordance with the invention, there is provided a collapsible, non-adjustable steering column assembly for a vehicle comprising: a support bracket for securing to a fixed part of the vehicle, the support bracket including an integrally formed guiding portion; and an tubular shroud portion which supports a steering column shaft and, in normal use, is fixed relative to the support bracket; wherein, in the event of a crash, the tubular shroud portion moves relative to, and is guided axially and controlled rotationally relative to a longitudinal axis of the shroud by the support bracket.

By “non-adjustable”, it is meant that the steering column assembly has no useroperable adjustment for reach - the overall length of the steering column assembly or rake - the angle of the steering column assembly.

The term “collision” is intended to include all the events surrounding the initial collision event, including, but not limited to, any effects of the initial collision such as the impact of the driver on the steering column assembly.

As the support bracket remains secured to a fixed part of the vehicle and provides guiding for the tubular shroud portion, the steering column assembly may collapse in a more controlled manner than would be possible using a known non-adjustable steering column assembly. Guiding of the tubular shroud portion may also ensure that energy absorbed during the collapse of the steering column is managed in a safe and controlled manner.

The support bracket may further comprise a connecting part for securing to a fixed part of the vehicle.

The length of the guiding portion is sufficient to allow sufficient clamping of the tubular shroud portion as well as guiding of the tubular shroud portion during a collapse stroke. The degree to which the tubular shroud portion is clamped will be set to a prescribed level so as to provide a suitable level of friction between the tubular shroud portion and the guiding portion of the support bracket during a collapse stroke.

The support bracket may be integrally formed as one part.

The tubular shroud portion and guiding portion may contact each other such that reactionary forces are produced in use between the tubular shroud portion and the guiding portion, the reactionary forces having components in orthogonal directions in a plane perpendicular to the longitudinal axis of the tubular shroud portion. The reactionary forces may have both positive and negative components in each direction.

The reactionary forces may prevent translational movement of the tubular shroud portion in the plane perpendicular to the longitudinal axis of the tubular shroud portion and/or relative rotation of the tubular shroud portion and guiding portion.

The guiding portion of the support bracket may be deformable so that it may be tightened around the tubular shroud portion, ensuring that tolerances can be adjusted for and the tubular shroud portion can be held in its operational position.

The guiding portion of the support bracket may include flexure elements for enabling adjustment of the guiding portion. The flexure elements may have a relatively lower thickness than the remainder of the guiding portion.

The tubular shroud portion may have a non-circular cross-section in a plane perpendicular to its longitudinal axis and preferably a polygonal cross-section. Preferably, the guiding portion of the support bracket and the profile of the inner column tube are of a geometrically similar shape, or substantially geometrically similar shape, to the tubular shroud portion. The polygonal cross-section may be octagonal or substantially octagonal.

By “geometrically similar”, it is meant that the guiding portion and tubular shroud portion have the same shape, that is, that one is a scale image of the other. Substantial geometrical similarity is meant to include those shapes whereby a significant portion of the shapes are similar and where other non-significant features differ.

Preferably, the guiding portion of the support bracket may include an elongate bearing surface, which extends in an axial direction of the tubular shroud portion, upon which the tubular shroud portion slides during the collision. Thus, the tubular shroud portion may be guided in a specific direction.

Multiple elongate bearing surfaces may be provided which complementarily engage with corresponding elongate bearing surfaces on the tubular shroud portion.

The tubular shroud portion may be fixed within the guiding portion of the support bracket, in normal use, by at least one frangible pin, the frangible pin being configured to fracture, in the event of a crash.

The collapsible, non-adjustable steering column assembly may further comprise an energy-absorbing member for absorbing energy during collapse of the steering column assembly.

The energy-absorbing member may be an energy-absorbing strap, the energy absorbing strap including a proximal end attached to one of the tubular shroud portion and support bracket.

The collapsible, non-adjustable steering column assembly may further comprise an anvil, attached to the other of the tubular shroud portion and the support bracket, around which the energy-absorbing strap deforms during collapse.

The anvil may be a bolt, preferably through the support bracket. The bolt may be a clamp bolt which allows tightening of the support bracket around the tubular shroud portion. This tightening may remove free play and set the level of friction between the guiding portion of the support bracket and tubular shroud portion.

The support bracket including the guiding portion may be produced by an extrusion process.

The assembly may further comprise an inner column tube, the inner column tube being receivable within the tubular shroud portion, the tubular shroud portion thus forming an outer column tube. Said inner column tube may provide additional guiding of the tubular shroud portion during collapse if required.

The invention will now be described in detail, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view from a first angle of a collapsible, nonadjustable steering column assembly in accordance with the invention;

Figure 2 is a perspective view of the collapsible, non-adjustable steering column assembly of Figure 1 from a second angle;

Figure 3 is a side view of the collapsible, non-adjustable steering column assembly of Figure 1, showing line B-B;

Figure 4 is a cross-sectional view of the non-adjustable steering column assembly of Figure 3, along line B-B;

Figure 5 is a side view of a second embodiment of the collapsible, nonadjustable steering column assembly, including an inner column tube.

Referring to the Figures, there is shown a steering column assembly 100 comprising a support bracket 102, tubular shroud portion 104, and shaft 106. The support bracket is secured to a fixed part of a vehicle (not shown) by two fixing points 108. Bolts may be used to secure the support bracket 102 to the vehicle, the bolts passing through the fixing points 108. However, other means of connecting the support bracket 102 to the vehicle may be used, with or without fixing points 108. The fixing points 108 may thus help define a connecting part of the support bracket 102 with the remainder of the support bracket 102 being termed a guiding portion 114.

One or more bearing assemblies 110 are positioned between the tubular shroud portion 104 and shaft 106 to provide this support and movement. A sensor cover 112 is provided fixed to the lower end of the tubular shroud portion by which a steering angle position sensor (not shown) may be covered.

The support bracket includes an integrally-formed guiding portion 114 which supports the tubular shroud portion 104 in a fixed position preventing relative movement. The shaft 106 is supported by the tubular shroud portion 104 such that rotational movement of the shaft 106 may occur relative to the tubular shroud portion 104. The present embodiment of the tubular shroud portion 104 is thus formed of a single part having a complementary cross sectional profile with that of the guiding portion of the support bracket 102.

The tubular shroud portion 104 is shaped such that, when moving relative to the guiding portion 114 during a crash, the tubular shroud portion 104 is guided both axially and rotationally by the guiding portion 114. Furthermore, due to the noncircular cross-section of both the tubular shroud portion 104 and the guiding portion

114 of the support bracket 102, the tubular shroud portion 104 is prevented from rotating relative to the support bracket 102 during collapse of the steering column assembly 100. At an end of the tubular shroud portion 104 furthest from the sensor cover 112, the tubular shroud portion 104 includes a portion with a circular crosssection, this portion including one of the bearing assemblies 110 which supports the shaft 106. The circular portion of the tubular shroud portion 104 may be produced by swaging or machining.

The tubular shroud portion 104 of the present embodiment has a substantially octagonal cross-section, perpendicular to a longitudinal axis of the tube, along a substantial portion of its length, including that which is housed within the guiding portion 114. Elongate bearing surfaces 116 are therefore provided on an outer surface of the tubular shroud portion 104 and on an inner surface of the guiding portion 114. These bearing surfaces 116 act to allow relative sliding motion between the tubular shroud portion 104 and guiding portion 114. Importantly, the bearing surfaces 116 should allow a prescribed sliding motion of the tubular shroud portion 104 relative to the guiding portion 114, when motion is allowed. Some friction may be desired and set to assist with the controlled collapse and can be provided using a clamp bolt 132, having a nut 136 on one end, can therefore be tightened to remove any free-play between the tubular shroud portion and the guiding portion 114 of the support bracket 102. This is not necessarily a requirement as other elements may be used to provide this functionality.

The bearing surfaces 116 contact each other such that reactionary forces are produced between the guiding portionll4 and the tubular shroud portion 104.

The reactionary forces sufficiently restrain the tubular shroud portion 104 such that it is guided axially by the guiding portion 114. More specifically, the tubular shroud portion 104 of the depicted embodiment is prevented from translating relative to the support bracket 102 in a plane perpendicular to the longitudinal axis of the tubular shroud portion 104. It is also prevented from rotating relative to the support bracket 102. However, in other embodiments, it may be desired to allow some controlled or predetermined relative rotation of the tubular shroud portion 104 and support bracket 102.

In order that the reactionary forces between the tubular shroud portion 104 and guiding portion 114 prevent translation of the tubular shroud portion 104 in a plane perpendicular to its longitudinal axis, the reactionary forces produced between the two components should have force components in orthogonal directions in said plane. By having both positive and negative components in both orthogonal directions, substantial relative translation can be avoided.

If the reactionary forces change direction during collapse of the steering column assembly in a collision, for instance because of the tubular shroud portion and/or guiding portion having a non-uniform shape along their length - i.e. one or both may twist along their respective longitudinal axes - then relative rotational motion may be allowed. However, this motion should be constrained such that it is sufficiently controlled to be predictable in its collapse characteristics.

Between many of the bearing surfaces 116 of the guiding portion 114, flexure elements are provided formed from two extending portions 134 of the support bracket 102. These flexure elements allow limited deformation of the guiding portion 114 such that tolerances and free play between the guiding portion 114 of the support bracket 102 and the tubular shroud portion 104 may be adjusted for.

The relatively long length of the support bracket 102 also ensures that the guiding of the tubular shroud portion 104 by the guiding portion 114 is smooth and immune from the effects of non-axial collapse forces that could otherwise cause the tubular shroud portion 104 to snag or drag on the inner surfaces of the guiding portion 114 during collapse. In conventional steering column assemblies a separate inner column tube is usually required in order to provide enough bearing length sufficient to provide the guiding motion that the present support bracket alone provides. The present arrangement therefore has a reduced part count, is lighter and more easily manufactured than conventional steering column assemblies that require an inner column tube.

Although the depicted embodiment is octagonal, it is possible to provide the tubular shroud portion 104 and guiding portion 114 with differently-shaped cross-sections, such as substantially heptagonal, hexagonal, pentagonal, square, or any other shape. It will also be possible to have a tubular shroud portion 104 and guiding portion 114 which are not of the same cross-section, as long as the shapes used still provide both axial and rotational guiding of the tubular shroud portion 104. The additional bearing surfaces 116 provided by a multi-faceted tubular shroud portion 104 increase the guiding properties of the steering column assembly 100.

Although the present embodiment utilises the cross-sectional shape of the tubular shroud portion 104 and guiding portion 114 to provide the guiding feature, it is also possible to provide this guiding through other means, such as providing a channel through which a portion of the tubular shroud portion slides. The restriction of rotation may also be provided in other ways which will be known to the skilled person.

In normal use - that is, prior to any collision resulting in collapse of the steering column - the tubular shroud portion 104 is held axially in position relative to the support bracket 102 by the clamping force of the guiding portion 114 around the tubular shroud portion 104. Breakaway can be additionally controlled by two frangible pins 118 which pass through apertures 120 in both the support bracket 102 and the tubular shroud portion 104. The frangible pins 118 fit tightly within the apertures 120, thus eliminating any slack or free-play in the axial direction. Upon the application of a high force, such as that which occurs during a collision, the frangible pins 118 are configured to fail in shear at the boundary between the tubular shroud portion 104 and the support bracket 102, allowing the tubular shroud portion 104 and support bracket 102 to move relative to one another in an axial direction. The frangible pins 118 are, in the present embodiment, pre-moulded such that they may be produced in a single step without any over-moulding or other additional manufacturing processes.

Securing means other than frangible pins 118 could be used, if desired. Such means could include resins or other materials which can be relied upon to fail upon the application of a specific force, or any other frangible fixture. Alternatively, it may be possible to provide the system using only friction providing the securing. Furthermore, a greater or lesser number of frangible pins 118 may be used, depending on individual requirements and other design considerations.

Once the tubular shroud portion 104 is able to move axially relative to the support bracket 102, it is desirable to manage the collapse and dissipation of energy within the steering column assembly 100. As such, an energy-absorbing strap 122 is used, the deformation of which absorbs energy during collapse of the steering column assembly 100, specifically, when the tubular shroud portion 104 moves relative to the support bracket 102.

A proximal end 124 of the energy-absorbing strap 122 is affixed to the tubular shroud portion 104, preferably by welding. The energy-absorbing strap 122 then wraps around an anvil 126 which is separate from the tubular shroud portion 104 - in the present embodiment it is secured to the support bracket 102 - and the distal ends 128 of the energy-absorbing strap 122 extend in a direction parallel to the length of the tubular shroud portion 104. The energy-absorbing strap 122 has a shape similar to that of a tuning fork, with one proximal end 124 and two distal ends 128. This allows the energy-absorbing strap 122 to be seated in a symmetrical manner, with one distal end 128 disposed either side of the proximal end 124 of the energy-absorbing strap 122, before deformation.

Upon movement of the tubular shroud portion 104 relative to the support bracket 102, the energy-absorbing strap 122 will also be moved, due to its connection to the tubular shroud portion 104, and will thus deform around the anvil 126, as the anvil 126 remains stationary relative to the support bracket 102. This deformation will absorb energy required to plastically deform the energy-absorbing strap 122, thus controlling the energy dissipation and collapse characteristics of the steering column assembly 100. Suitable materials for the energy-absorbing strap 122 will be known to the skilled person but may include metals and other sufficiently ductile materials. The energyabsorbing strap 122 should preferably be longer than the maximum relative movement of the tubular shroud portion 104 and support bracket 102 during collapse. This ensures that there is no uncontrolled relative movement of the tubular shroud portion 104 and support bracket 102. The energy-absorbing strap 122 can be tuned such that it gives a predetermined energy absorption or collapse rate.

The support bracket 102, in order to accommodate the connection of the energyabsorbing strap 122 to the tubular shroud portion 104, includes a split 130 along the bottom of the guiding portion 114. This split 130 may thus introduce a little free-play into the guiding portion 114 of the support bracket 102. The anvil 126 is therefore formed as part of a clamp bolt 132 which allows tightening of two extending portions

134 of the support bracket 102 which extend away from the tubular shroud portion 104, either side of the split 130. The clamp bolt 132, having a nut 136 on one end, can therefore be tightened to remove any free-play, and optionally to apply a clamping load, between the tubular shroud portion 104 and support bracket 102. In an alternative configuration, the clamp bolt 132 and anvil 126 may be separate components, if desired.

Although the energy-absorbing strap 122 is described as being connected to the tubular shroud portion 104, it is also possible to provide the energy-absorbing strap 122 in an alternative position whereby it is connected to the support bracket 102. In this alternative, the anvil 126 would require connecting to the tubular shroud portion 104, in order to maintain functionality. The energy-absorbing strap 122 could also be connected at both proximal and distal ends 124, 128, and the anvil 126 may be dispensed with in favour of coiling of the energy-absorbing strap 122. Subsequent uncoiling would provide the plastic deformation without any requirement to provide an anvil 126. Other options will also be known to the skilled person.

Given the shape of the support bracket 102, in particular the guiding portion 114, the support bracket 102 may be manufactured by extrusion, giving the constant crosssection required. Simple machining can then produce the apertures 120, fixing points 108, and other fine details, if present. This manufacturing process allows the support bracket 102 to be produced in a much more cost-effective and efficient manner. For example, in the present embodiment, the only secondary machining required is that of cutting the extrusion to length and machining the six holes required for the fixing points 108, the frangible pins 118, and the clamp bolt 132.

A switch mount 138 is located towards the end of the shaft 106 at which the handwheel (not shown) is attached. The switch mount 138 provides a mounting point for a combination switch lever and/or a key lock. The switch mount 138 is optional and need not be provided if not required.

Finally, a second embodiment of a steering column assembly 200 in accordance with the invention is shown in Figure 5. The embodiment is identical to Figure 3 in most aspects including identical reference numerals and therefore substantial description is omitted, for brevity. However, the second embodiment of the assembly 200 also includes an inner column tube 242 and the outer column tube is therefore slightly shortened, although this is not a necessity. The inner column tube 242 is received within the tubular shroud portion 104 which may therefore be termed the outer column tube 104, the inner column tube 242 and outer column tube 104 together making up the shroud. The inner column tube may therefore provide more support, stability and/or guiding to the outer column tube during a collapse of the assembly 200.

Claims

1. A collapsible, non-adjustable steering column assembly for a vehicle comprising:

a support bracket for securing to a fixed part of the vehicle, the support bracket including an integrally formed guiding portion; and a tubular shroud portion which supports a steering column shaft and, in normal use, is fixed relative to, and at least partially within, the guiding portion;

wherein, in the event of a crash, the tubular shroud portion moves relative to, and is guided axially and controlled rotationally relative to a longitudinal axis of the tubular shroud portion by the support bracket.

2. A collapsible, non-adjustable steering column assembly as claimed in claim 1, wherein the support bracket further comprises a connecting part for securing to a fixed part of the vehicle.

3. A collapsible, non-adjustable steering column assembly as claimed in any preceding claim, wherein the support bracket is integrally formed as one part.

4. A collapsible, non-adjustable steering column assembly as claimed in any preceding claim, wherein the tubular shroud portion and guiding portion contact each other such that reactionary forces are produced in use between the tubular shroud portion and the guiding portion, the reactionary forces having components in orthogonal directions in a plane perpendicular to the longitudinal axis of the tubular shroud portion.

5. A collapsible, non-adjustable steering column assembly as claimed in claim 4, wherein, in use, the reactionary forces have both positive and negative components in each direction.

6. A collapsible, non-adjustable steering column assembly as claimed in claim 5, wherein the reactionary forces prevent translational movement of the tubular shroud portion in the plane perpendicular to the longitudinal axis of the tubular shroud portion.

7. A collapsible, non-adjustable steering column assembly as claimed in claim 6 or claim 8, wherein the reactionary forces prevent relative rotation of the tubular shroud portion and guiding portion.

8. A collapsible, non-adjustable steering column assembly as claimed in any preceding claim, wherein the guiding portion is deformable.

9. A collapsible, non-adjustable steering column assembly as claimed in claim 8, wherein the guiding portion includes flexure elements for enabling adjustment of the guiding portion.

10. A collapsible, non-adjustable steering column assembly as claimed in claim 9, wherein the flexure elements have a relatively lower thickness than a remainder of the guiding portion.

11. A collapsible, non-adjustable steering column assembly as claimed in any preceding claim, wherein the tubular shroud portion has a non-circular cross-section in a plane perpendicular to the longitudinal axis of the tubular shroud portion.

12. A collapsible, non-adjustable steering column assembly as claimed in any preceding claim, wherein the guiding portion of the support bracket is a geometrically similar shape, or substantially geometrically similar shape, to the tubular shroud portion.

13. A collapsible, non-adjustable steering column assembly as claimed in any preceding claim, wherein the tubular shroud portion has a polygonal cross-section in a plane perpendicular to the longitudinal axis of the tubular shroud portion.

14. A collapsible, non-adjustable steering column assembly as claimed in claim 13, wherein the polygonal cross-section is octagonal or substantially octagonal.

15. A collapsible, non-adjustable steering column assembly as claimed in any preceding claim, wherein the guiding portion includes an elongate bearing surface, which extends in an axial direction of the tubular shroud portion, upon which the tubular shroud portion slides during the collision.

16. A collapsible, non-adjustable steering column assembly as claimed in claim 15, wherein multiple elongate bearing surfaces are provided, which complementarily engage with corresponding elongate bearing surfaces on the tubular shroud portion.

17. A collapsible, non-adjustable steering column assembly as claimed in any preceding claim, further comprising an energy-absorbing member for absorbing energy during collapse of the steering column assembly.

18. A collapsible, non-adjustable steering column assembly as claimed in claim 17, wherein the energy-absorbing member is an energy-absorbing strap, the energy absorbing strap including a proximal end attached to the tubular shroud portion or support bracket.

19. A collapsible, non-adjustable steering column assembly as claimed in claim 18, further comprising an anvil, attached to the other of the tubular shroud portion or support bracket, around which the energy-absorbing strap deforms during collapse.

20. A collapsible, non-adjustable steering column assembly as claimed in claim 19, wherein the anvil is a bolt through the support bracket.

21. A collapsible, non-adjustable steering column assembly as claimed in claim 20, wherein the bolt is a clamp bolt which allows tightening of the support bracket around the tubular shroud portion.

22. A collapsible, non-adjustable steering column assembly as claimed in any preceding claim, the support bracket having been produced by an extrusion process.

23. A collapsible, non-adjustable steering column assembly as claimed in any preceding claim, further comprising an inner column tube, the inner column tube being receivable within the tubular shroud portion, the tubular shroud portion thus forming an outer column tube.

24. A support bracket for use in a non-adjustable steering column assembly, the support bracket including a connecting part for attachment to a fixed part of a vehicle and an integrally formed guiding portion for locating and guiding a corresponding tubular shroud portion.

25. A support bracket as claimed in claim 24, wherein the guiding portion is deformable.

26. A support bracket as claimed in claim 25, wherein the guiding portion includes flexure elements for enabling adjustment of the guiding portion.

27. A support bracket as claimed in claim 26, wherein the flexure elements have a relatively lower thickness than a remainder of the guiding portion.

28. A support bracket as claimed in any one of claims 24 to 27, wherein the guiding portion has a non-circular cross-section in a plane perpendicular to its longitudinal axis.

29. A support bracket as claimed in claim 28, wherein the non-circular crosssection is a polygonal cross-section.

30. A support bracket as claimed in claim 29, wherein the polygonal cross-section is octagonal or substantially octagonal.

31. A support bracket as claimed in any of claims 24 to 30, further comprising an elongate bearing surface for providing a surface upon which the corresponding tubular shroud portion may slide, during a collision.

32. A support bracket as claimed in claim 31, wherein multiple elongate bearing surfaces are provided.

33. A support bracket as claimed in any one of claims 24 to 32, further comprising a clamp bolt which allows tightening of the guiding portion.

34. A support bracket as claimed in any one of claims 24 to 33, the support bracket having been produced by an extrusion process.

Intellectual

Property

Office

Application No: GB 1620467.9 Examiner: Mr Tom Wilson