GB2276702A - Steering wheel. - Google Patents

Abstract

A hub 1 has resiliently bendable axial arms 26 whose distal end portions have transverse latching surfaces 28 cooperating with striking surfaces 31 on a hollow pod 4 so as to obstruct accidental axial separation of the pod 4 from the hub 1. The bendable arms 26 allow manual removal of the part 4 by a peeling motion relative to the hub 1. <IMAGE>

Description

Steering Wheel This invention relates to a steering wheel for a vehicle.

A steering wheel may include a hollow pod which incorporates a horn push and which is mounted on a hub to which the rim of the wheel is connected by one or more spokes. Accurate location of the pod on the hub is important because it is highly visible to the driver. However, although the pod must be positively located on the steering wheel, it must be easy to assemble during vehicle production and must be easy to detach during servicing.

In a known arrangement the hub is of plastics material and has two or more apertures or recesses, and a plate on the rear of the pod carries moulded plastics pins with enlarged heads which are partially slotted to allow them to deform as they are forced into the apertures or recesses, where they are held by friction.

The friction required to hold the pod to be relatively high for the following reasons. In extreme dynamic situations, in particular a vehicle head-on collision situation, the steering column tends to be jerked back in the axial direction relative to the passenger compartment, and the momentum thus imparted to the pod can tend to pull the pins out of the hub. In order to further reduce the instances where the pod may separate from the hub, it is necessary to increase the frictional engagement between the pins and the hub, for example by increasing the size of the enlarged head relative to the aperture or recess, or by providing two enlarged sections on each pin. However, it then becomes harder to assemble the steering wheel and to detach the pod for servicing. If this pin and aperture engagement structure is used to provide optimum friction which avoids accidental separation of the pod but enables reasonably easy removal for servicing, it requires a high degree of tolerance control in the manufacture of both parts.

What is desired is a steering wheel in which it is easy to fit and detach the pod manually but accidental detachment of the pod is effectively prevented without necessitating costly manufacturing tolerance control.

The present invention provides a steering wheel including a hub member and a hollow member removably mounted on the hub member, one of the said members having resiliently bendable arms projecting towards the other member, the distal end portions of the respective arms having respective transverse latching surfaces which face the said one member and which cooperate with respective striking surfaces on the said other member so as to obstruct relative movement of the two members away from each other.

Thus, while it is possible for the latching surfaces of the arms to effectively prevent accidental detachment of the hollow member from the hub member1 the bendability of the arms allows the hollow member to be fitted and removed without difficulty.

The invention will be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a fragmentary axial view of a steering wheel, in a first embodiment of the invention; Figure 2 is a section on line II-II in Figure 1; Figure 3 is a diagrammatic section on line III-III in Figure 1, showing a latching clip in relation to a striking plate; Figure 4 is a diagram (similar to Figure 3) illustrating how the striking plate is fitted over the clip; Figure 5 is a similar diagram, illustrating how the striking plate can be removed from the clip; Figure 6 is a similar diagram, illustrating how the clip obstructs accidental detachment of the striking plate; Figure 7 diagrammatically shows one arm of a latching clip in a second embodiment of the invention; Figure 8 diagrammatically shows one arm of a latching clip in a third embodiment; Figure 9 is a plan view of a latching clip in a fourth embodiment; and Figure 10 is a plan view of a latching clip in a fifth embodiment.

The steering wheel illustrated has a moulded plastics hub 1 which is extended to form spokes 2 which merge with a rim 3. A hollow central pod 4 is mounted on the hub 1, and at each side it abuts against the spoke 2 at an interface 6.

The pod 4 has a flexible covering 7 whose central region 8 is depressible and carries one contact of a switch 9 for activating a horn. The pod II includes a metal mounting plate 11 (also referred to below as a striking plate), which is fitted with pins 12 made of moulded plastics (or any other suitable resilient material) with partially slotted enlarged heads 13 which are a friction fit in blind holes 14 in the hub 1.

In order to prevent axial detachment of the pod 4 in a direction parallel to the steering column axis 16, the hub 1 is provided with a clip 17 fabricated from spring steel sheet (approximately 0.5 mm thick). The clip 17 includes a flat ring or washer 18 which is retained on the hub 1 by a nut 19 which retains the hub 1 on the steering column 21 (Figure 3). The clip 17 also has retention legs 22 formed with tangs 23 for engaging in location recesses 24 in the hub 1, thereby to hold the clip in the desired position prior to assembly of the steering wheel on to the steering column. It is to be noted that, although the legs 22 are shown in Figure 3, this Figure is only diagrammatic, and the legs 22 would in fact not be visible in the cross-section taken along line III-III shown in Figure 1.

The clip 17 also has two arms 26, which extend parallel to the axis 16 and project through a circular aperture (centered on the axis 16) in the striking plate 11. Between each arm 26 and the nut 19 there is sufficient space for the arm to bend inwardly during the operations of fitting and detaching the pod 4. The distal end portion of the arm 26 is bent to form a latching surface 28 and a ramp surface 29. In the embodiment shown in Figures 1 to 3, the latching surface 28 extends at right angles to the axis 16 and is spaced from a mutually parallel striking surface 31 defined on the inside of the mounting plate 11. The spacing facilitates manual removal of the pod 4.

As can be seen in Figure 11, when the pod 4 is fitted to the hub 1, by applying it in a direction parallel to the axis 16, the mounting plate 11 rides over the ramp surfaces 29, causing the arms 26 to bend inwards (in the manner of leaf springs), thereby allowing the distal end portions of the arms to pass through the aperture 27.

As can be seen in Figure 1, the arms 26 are arranged with their longitudinal axes lying in a plane 32 which contains the axis 16 and is approximately parallel to the interface 6, which thus serves as a visual guide for the manual removal of the pod Figure 5 shows what happens during manual removal, in which the pod 4 is "peeled" from the hub 1. During this operation, the pins 12 are gradually pulled out of the holes ILI and are resiliently deformed while the pod 4 is urged sideways in a direction parallel to the interface 6, so that one of the arms 26 is bent inwards (as shown in Figure 5) to such an extent that the striking plate 11 can escape past the latching surface 28 of the other arm. To facilitate this, it may be possible to make the first-mentioned arm more easily bendable, e.g. by making it narrower.

Figure 6 shows what happens if the pod 4 is accidentally urged in the axial direction, as may happen during a collision.

In this situation, the pins 12 are urged to be pulled out of the holes 14, but the striking surfaces 31 inside the mounting plate 11 abut against the latching surfaces 28 so that the arms 26 are put under tension in the axial direction. The bent distal end portions of the arms prevent detachment of the pod 4 in the axial direction, since a very high force is needed to deform the distal end portions sufficiently to allow them to pass through the aperture 27 in the striking plate 11.

Various modifications may be made within the scope of the invention. For example, it is possible for the arms to serve as the means for fixing the pod 4 to the hub 1, so that the pins 12 can be omitted. The arms can at least assist the fixing of the pod 4 to the hub 1, e.g. by frictional engagement between the arms 26 and the mounting plate 11. In particular, as shown in Figure 7, the arms 26 may have corrugated surfaces 33 engaged with an edge portion of the striking plate 11.

Figure 8 shows a different way of bending the distal end portion of the arm 26. In this case, furthermore, the latching surface 28 inclines towards the hub with increasing distance from the arm 26. This enhances the latching of the mounting plate 11.

This effect is further enhanced by bending the edge portion of the mounting plate inwards so that the striking surface 31 is approximately parallel to the latching surface 28. A clip with arms having distal end portions of such wedge-shaped cross-section may also be made of moulded plastic material.

In Figure 9, a clip 17 is shown which has three arms 26 equi-angularly spaced around the axis 16. Furthermore, one arm 26' is narrower than the others and therefore more easily bendable. As shown in Figure 9, it is possible to omit the legs 22, particularly if the clip 17 is adhesively fixed to the hub.

Alternatively, legs of any suitable form can be embedded in the hub during a moulding process.

Figure 10 shows a clip 17 having a multiplicity of arms 26 (in particularly six arms equally spaced around the clip).

Furthermore, in this case the set of arms 26' lying on one side of a plane 34 (containing the axis 16 and orthogonal to the plane 32) is more easily bendable than the set of arms 26 on the opposite side, thereby facilitating manual removal of the pod 4.

Thus, as with the above described embodiments, the peeling required to remove the pod 4 from the hub 1 is highly directional, so that the pod 4 is well secured against accidental separation from the hub 1.

Claims (27)

CLAIMS:

1. A steering wheel including a hub member and a hollow member removably mounted on the hub member, one of the said members having resiliently bendable arms projecting towards the other member, the distal end portions of the respective arms having respective transverse latching surfaces which face the said one member and which cooperate with respective striking surfaces on the said other member so as to obstruct relative movement of the two members away from each other.

2. A steering wheel as claimed in claim 1, in which the distal end portion of each arm has an oblique ramp surface facing away from the said one member.

3. A steering wheel as claimed in claim 1 or 2, in which the distal end portion is a bent portion of the arm.

4. A steering wheel as claimed in any of claims 1 to 3, in which each arm extends substantially parallel to the axis of rotation of the steering wheel.

5. A steering wheel as claimed in any of claims 1 to 4, in which the latching surface is substantially at right angles to the axis of rotation of the steering wheel.

6. A steering wheel as claimed in any of claims 1 to 4, in which the latching surface inclines towards the said one member with increasing distance from the arm.

7. A steering wheel as claimed in any of claims 1 to 6, in which the striking surface is substantially parallel to the latching surface.

8. A steering wheel as claimed in any of claims 1 to 7, in which the striking surface is spaced from the latching surface.

9. A steering wheel as claimed in any of claims 1 to 8, in which the said other member is frictionally engaged with the arms.

10. A steering wheel as claimed in claim 9, in which each arm has a corrugated surface engaged with an edge portion of the corresponding striking surface.

11. A steering wheel as claimed in any of claims 1 to 10, in which each arm is in the form of a leaf spring.

12. A steering wheel as claimed in any of claims 1 to 11, in which at least one arm is more easily bendable than the rest.

13. A steering wheel as claimed in any of claims 1 to 12, in which the arms are distributed about the axis of rotation of the steering wheel.

14. A steering wheel as claimed in claim 13, in which the arms are spaced, preferably equally, around a circle.

15. A steering wheel as claimed in claim 13 or 14, in which there are two arms having longitudinal axes lying in a plane containing the said axis of rotation.

16. A steering wheel as claimed in claim 13 or 14, in which there are three arms.

17. A steering wheel as claimed in claim 14, in which there are at least four arms.

18. A steering wheel as claimed in claim 17, in which there are at most six arms.

19. A steering wheel as claimed in claim 17 or 18, in which a given plane containing the rotation axis of the steering wheel divides the arms into two sets, one set being more easily bendable than the other set, as a whole.

20. A steering wheel as claimed in any of claims 1 to 19, in which the arms are on the hub member and the striking surfaces are on the hollow member.

21. A steering wheel as claimed in claim 20, in which the arms are integral with a ring fixed to the hub member.

22. A steering wheel as claimed in claim 21, in which the ring has legs located in recesses in the hub member.

23. A steering wheel as claimed in claim 21 or 22, in which the ring is interposed between the hub member and a nut for retaining the hub member on the steering column.

24. A steering wheel as claimed in any of claims 20 to 23, in which the striking surfaces are provided inside at least one aperture in a plate fixed to the hollow member.

25. A steering wheel as claimed in claim 24, in which the aperture is coaxial with the axis of rotation of the steering wheel.

26. A steering wheel as claimed in any of claims 1 to 25, in which at least one of the said members has a pin frictionally engaged in a hole in the other of the said members.

27. A steering wheel substantially as described with reference to any of the embodiments illustrated in the accompanying drawings.