Vehicle steering column assembly

Abstract: A vehicle steering column assembly with an adjustment means for rake and/or reach adjustment includes a guiding member (7) located in a guiding slot (6). In one form, the slot (6) is located in a support bracket (5) and is inclined rearwardly towards a steering wheel (3). With rake adjustment, the guided member (7) travels up the slot and towards the steering wheel end. In the event of crash impact, force is transmitted from the steering column (1) from the steering wheel (3), thereby inhibiting upward travel of the guiding member (7) against the inclined slot (6), thereby preventing lifting of the steering wheel (3). In a modification, the slot (6) is serrated and the guiding member (7) is toothed but normally rides smoothly on an interposed liner (10). On crash impact, the teeth of the guided member (7) pierce the liner (6) to engage and jam with the serrations (6B).

Description: This invention relates to a vehicle steering column assembly with a rake and/or reach adjustment means. Rake adjustment of a steering wheel is the direction of adjustment whereby the steering wheel with its column, or at least part of it, can be raised or lowered. Reach adjustment enables the steering wheel to be moved towards and away from the driver. In the event of a vehicle crash, a crash force is transmitted in reaction to the collision in a direction towards the front of the vehicle and away from the steering wheel. With a rake adjustable steering column and wheel, there is a tendency in crash conditions for the steering wheel to rise, thereby to cause injury to the driver. The document JP-A-07232649, which concerns a steering column assembly according to the preamble of claim 1, discloses toothed means for preventing such a rising movement of the steering wheel when a vehicle crash occurs. According to the present invention, there is provided a vehicle steering column assembly with an adjustment means, said assembly including a steering column having a lower end for coupling to a steering mechanism and an upper end to which a steering wheel can be coupled, and said adjustment means including a guiding member located in a guiding slot of the assembly, thereby to provide said adjustment; characterised in that said slot has an edge serving as a detent and said guiding member having engagement means to engage and lock with said detent edge, and there being a liner interposed between said detent edge and said engagement means so as normally to prevent such engagement and locking of said guiding member; and said liner being pierceable by said engagement means of said guiding member upon transmission of sufficient force through the steering column in a direction from said upper end towards said lower end thereof and thence to said guiding member, which thereby serves to prevent movement of the steering column in an adjustment direction by reason of said engagement. The guiding slot may be located in a support bracket of the vehicle steering column assembly. The edge of the guiding slot serving as a detent may be formed as a serrated edge and the guiding member may include a toothed part to pierce the liner and engage the serrated edge. The guiding member of the adjustment means may include a block which rides in the guiding slot. The vehicle steering column assembly can be a rake adjustable and/or a reach adjustable steering column assembly. The invention also extends to a vehicle incorporating a vehicle steering column assembly. For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawing, in which:- Figure 1 is a diagrammatic side view of a vehicle steering column assembly with a rake adjustment means, and Figure 2 is an enlarged view of part of the assembly illustrated in Figure 1 and showing a modification which can be used in its own right or incorporated in the embodiment illustrated in Figure 1. Referring to the drawing, Figure 1 shows a vehicle steering column assembly including a steering column 1 having a lower end 1A coupled to a steering rack 2 and an upper end 1B, to which a steering wheel 3 is coupled. The steering column 1 is mounted by means of a support bracket 4 which is mounted at points 5 to another part of the vehicle. The form of steering column assembly illustrated in Figure 1 is rake adjustable substantially in the directions of the double arrow A. To facilitate this rake adjustment, at least one guiding slot 6 is cut into the support bracket 5 and is inclined rearwardly towards its upper end 6A. In other words, the slot 6 extends at an angle with respect to the major axis of the steering column 1 such that a guiding member 7 located in the guiding slot 6 to provide the rake adjustment travels, in use, from a lower part of the slot 6 to an upper part of the slot and towards the steering wheel end of the steering column as the steering column 1 is lifted. The guiding member 7 forms part of a clamping mechanism to clamp the steering column in the desired position. It will be appreciated that, with the guiding slot 6 so angled, slight movement of the steering column will also be required in the direction of the arrow B, i.e. towards the driver, in order to allow the steering wheel 3 to be lifted. However, the purpose of the guiding slot 6 being so angled is so that, in a crash condition, when a crash force is transmitted from the steering wheel 3 towards the steering rack 2 substantially in the direction of the arrow C, lifting of the steering column 1 and thus the steering column 3 towards the driver is prevented to prevent injury to the driver, since the locking member 7 is prevented from riding up the angled slot 6 in the direction opposite to the direction of the force C. Figure 2 illustrates an extension of the embodiment shown in Figure 1. The guiding member 7 for the adjustment of the steering column (in this case which can be rake and/or reach adjustable) is in the form of a clamp bolt mounted in a substantially rectangular block 8 by means of an insert 9 having hardened teeth 9A. The block 8 is guided by and runs along a liner 10 of the guiding slot 6. The liner 10 may be made of a plastics material or other material softer than the teeth 9A of the insert 9. As shown, one edge of the guiding slot 6 is provided with teeth 6B serving as a detent edge. The teeth 9A of the toothed insert 9 face the teeth 6B but, as can be seen, the liner 10 is normally interposed between the teeth of the insert and the teeth of the slot. Accordingly, the block 8 can slide freely within the slot 6 and along the slot liner 10. However, in the event of a crash, forces are transmitted substantially in the direction of the arrow C (the same as in Figure 1) and this causes the teeth 9A of the insert 9 to be driven through the material of the liner 10 thereby to engage with the teeth 6B of the detent edge of the guiding slot 6. With the slot liner so pierced, the assembly is jammed, thereby to prevent especially rising movement of the steering wheel 3.

Claims: A vehicle steering column assembly with an adjustment means, said assembly including a steering column (1) having a lower end (1A) for coupling to a steering mechanism (2) and an upper end (1B) to which a steering wheel (3) can be coupled, and said adjustment means including a guiding member (7) located in a guiding slot (6) of the assembly, thereby to provide said adjustment; characterised in that said slot has an edge (6B) serving as a detent and said guiding member (7) having engagement means (9A) to engage and lock with said detent edge, and there being a liner (10) interposed between said detent edge (6B) and said engagement means (9A) so as normally to prevent such engagement and locking of said guiding member (7); and said liner (10) being pierceable by said engagement means (9A) of said guiding member upon transmission of sufficient force through the steering column (1) in a direction from said upper end (1B) towards said lower end (1A) thereof and thence to said guiding member, which thereby serves to prevent movement of the steering column in an adjustment direction by reason of said engagement. An assembly according to claim 1, wherein the edge of the guiding slot (6) serving as a detent is formed as a serrated edge (6B) and the guiding member (7) includes a toothed part (9A) to pierce the liner and engage the serrated edge. An assembly according to claim 2, wherein the guiding member includes a block (8) which rides in the guiding slot. An assembly according to claim 1, 2 or 3, wherein the assembly is a rake adjustable and/or a reach adjustable steering column assembly. An assembly according to any one of the preceding claims, wherein said guiding slot (6) is located in a support bracket (4) of the vehicle steering column assembly. A vehicle incorporating a vehicle steering column assembly according to any one of the preceding claims.

Inventors: BARTON LAURENCE GEORGE HERBERT, BARTON, LAURENCE GEORGE HERBERT
Applicants: NASTECH EUROP LTD, NASTECH EUROPE LIMITED
Application year: 1996
Main classification: B62D1
IPC codes: B62D1