GB2260953A

GB2260953A - Axially adjustable and retractable vehicle steering columns

Info

Publication number: GB2260953A
Application number: GB9216226A
Authority: GB
Inventors: Michael Thomas Hancock
Original assignee: Torrington Co Ltd; Torrington Co
Current assignee: Torrington Co Ltd; Timken US LLC
Priority date: 1991-10-30
Filing date: 1992-07-30
Publication date: 1993-05-05
Also published as: GB9216226D0; GB9122962D0

Abstract

A mechanism for locking an axially adjustable vehicle steering column in a crash situation comprises a wedging mechanism which includes a pivot block (6) having a plastics locator plug (8) normally spacing the wedging mechanism clear of a mounting bracket (4). At least one blade (10) is provided in the pivot block for digging into part of the steering column mounting, which occurs upon crash, when the pivot block (6) is pulled by a cable (11), to prevent further axial movement of the steering column within its adjustment range. Eventually the steering column is pulled away from its breakaway mounting point 5. The wedging blades 10 may be replaced by wedging platforms (10A, Fig 8) or serrations (10B, Fig 9). <IMAGE>

Description

LOCKING MECHANISM FOR A VEHICLE STEERING COLUMN This invention relates to a locking mechanism for a vehicle steering column.

In a crash situation it is desirable that the vehicle's steering wheel can be moved axially forward away from the driver in order to prevent the driver impacting on the steering wheel. This has been achieved by a cable activated by the rearward movement of the engine following the crash pulling a break-away column mounting forward.

The mounting then causes the column with steering wheel to move forward. However, this clearly relies on the column with associated structure and steering wheel being relatively fixed and non-adjustable. In the case of an adjustable column with its structure, there still remains a problem as to how to cause the steering wheel to be moved out of the possible impact zone of the driver.

According to the present invention there is provided a locking mechanism for locking an axially adjustable vehicle steering column in a crash situation comprising a steering column structure mounted for axial movement to a break away mounting and a wedging mechanism arranged to lock the column structure to the mounting upon a crash.

Whatever the adjusted axial position of the column structure relative the mounting, the column is locked to the mounting upon the crash. A known arrangement then causes the mounting to be broken away from the structure of the vehicle.

The locking mechanism is preferably actuated by means of a cable which is arranged to pull substantially in the axial direction of the steering column towards the front of the vehicle.

Preferably the wedging mechanism comprises a tilting means which may be a pivot block mounted pivotally to the mounting.

The pivot block can be made of aluminium or aluminium alloy and can be arranged so that in its normally-pivoted position (prior to any crash situation) it has a part of it resting against or just clear of, for example, the underside of the aforementioned steering column structure.

The pivot block can either be resiliently loaded into that condition or be normally held clear of the column structure.

The main body of the pivot block can be spaced from the steering column structure by a short distance by means of, for example, a plastics plug set into an orifice in the pivot block, the tip of the plastic plug resting against the steering column structure.

Adjacent to the plug is provided a blade, which can be of hardened steel or a sintered component, for example, and it is this blade which, in a crash situation, is caused to dig into the steering column mounting as the pulling means causes the pivot means to pivot so that the blade goes into wedging engagement. In the case of a sliding steering column this wedging engagement prevents axial movement of the steering column within its adjustment range and the effort of the pulling means is directed such that, through the wedged pivot block, the steering column is pulled away from its breakaway mounting point.

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 drawings, in which:- Figure 1 is a diagrammatic view of a slidable and adjustable steering column incorporating a mechanism to cause it to be demounted in the event of a crash situation, Figure 2 is a diagrammatic sectional view of the pivot means, Figure 3 is a diagrammatic view of the pivot means mounted in its normal position, Figure 4 illustrates in greater detail the present mechanism, Figure 5 is a perspective view showing in greater detail a pressing illustrated in Figures 3 and 4, which is a linear adjustment bracket of the steering column, Figure 6 is a side view of the pressing shown in Figure 5, Figure 7 is an underneath view of the pressing shown in Figure 5, Figure 8 is a perspective view of a modified version of pivot block illustrated in Figures 2 to 4, and Figure 9 is a view similar to Figure 8 showing a further modification.

Referring to the drawings, Figure 1 shows a steering column 1 with steering wheel 2 and a structure 3 which allows it to be axially slidably adjusted. The structure 3 is mounted for axial movement in a bracket 4 which forms a steering column mounting with a breakaway mounting area 5 where the bracket 4 is mounted to another part of the vehicle structure or body.

The steering column structure 3 includes an outer tube 15 and a generally U-shaped pressing 9 which extends downwards. Pivotally mounted to the pressing 9 about a pivot pin 7 is a pivot block 6 having a plastics locator plug 8 which is normally located preferably by a resilient means in a non-crash condition against or slightly clear of the roof of pressing 9.

The locator plug is formed of for instance nylon with a stem 8' of smaller diameter than the head 8'' the purpose for which will be described below.

Located close to the plastics locator is an insert block in the pivot block 6 and constituting a wedging means in the form of a blade 10 which, as can be seen from Figure 4, has a tip which is normally held clear of contact with the pressing by the plastic locator.

Taking a line which passes through the pivot axis of the pivot pin 7 and the blade 10, one arrives at a location on the opposite side of the pivot block 6, i.e. remote from the blade 10. It is in the region of this opposite side that the pulling means is engaged to the pivot block to rotate it in the event of a crash of the vehicle.

The pulling means is in the form of a cable 11 which generally extends parallel to the axis of the steering column.

In the embodiment illustrated, the pivot block 6 and associated parts are incorporated in the sliding steering column mechanism and it will be seen that the pivot axis 7 is normally laterally moveable along a slot 12 so as to adjust the steering wheel position.

In the event of a crash situation, the cable 11 will be pulled in a direction which is to the left as viewed in Figures 1, 2 and 4, and this causes the pivot block 6 to rotate sharply about its pivot 7 in the direction of the arrow A in Figure 4, which has the result of compressing the plastics locator 8 and crushing its stem. The blade 10 is thereby caused to dig into the roof of the pressing 9 so that the pivot block assembly is wedged and so is prevented from sliding along the slot 12 for normal column adjustment. Continued pull of the cable 11 then pulls the complete steering column 1 from the breakaway mounting 5 away from the driver.

It will be appreciated that more than one plastics locator 8 or the like can be provided and, similarly, the wedging blade 10 is only one particularly preferred form of wedging means to cause the pivot means to wedge against a part of the steering column structure upon crash. In the form illustrated, it will be noted that two wedging projections of blade 10 are provided.

Figures 5 to 7 show in greater detail a preferred form of pressing 9 and it will be seen that the underside of it can have a plain surface, as shown in the right-hand side of Figures 6 and 7, or can be provided with serrations 9A as shown in the left-hand side of those Figures. In either case, the wedging zone of the pivot block 6 will lock against the underside of the pressing 9, against the plain surfaces of the serrated surfaces respectively.

Figure 8 shows another form of pivot block 8 in which the wedging blade 10 is substituted by a pair of plain surface wedging platforms 10A for wedging against the underside of the pressing 9.

Figure 9 shows a modification to the wedging platforms, in that the wedging platforms 10B are serrated.

Claims

CLAIMS:

1. A locking mechanism for locking an axially adjustable vehicle steering column in a crash situation comprising a steering column structure mounted for axial movement to a break away mounting and a wedging mechanism arranged to lock the column structure to the mounting upon a crash.

2. A locking mechanism according to claim 1, wherein it is actuated in use by means of a cable which is arranged to pull substantially in the axial direction of the steering column towards the front of the vehicle.

3. A locking mechanism according to claim 1 or 2, wherein the wedging mechanism comprises a tilting means.

4. A locking mechanism according to claim 3, wherein said tilting means is a pivot block mounted pivotally to the mounting.

5. A locking mechanism according to claim 4, wherein the pivot block is made of aluminium or aluminium alloy.

6. A locking mechanism according to claim 4 or 5, wherein said pivot block is arranged so that in its normallypivoted position it has a part of it resting against or just clear of the underside of said steering column structure.

7. A locking mechanism according to claim 6, wherein said pivot block is resiliently loaded into its normally-pivoted position.

8. A locking mechanism according to any one of claims 4 to 7, wherein the main body of the pivot block is spaced from the steering column structure by a short distance by means of a plastics plug set into an orifice in the pivot block, the tip of the plastics plug resting against the steering column structure.

9. A locking mechanism according to claim 8, wherein a blade is provided adjacent to the plug, which blade is caused to dig into the steering column mounting as the tilting means is caused to pivot so that the blade goes into wedging engagement.

10. A locking mechanism according to claim 9, wherein said blade is made of hardened steel or a sintered component.

11. A locking mechanism according to any one of claims 4 to 7, wherein said pivot block is provided with a wedging platform with at least one plain area for wedging engagement with part of the steering column structure.

12. A locking mechanism according to any one of claims 4 to 7, wherein said pivot block is provided with a wedging platform with at least one serrated area for wedging engagement with part of the steering column structure.

13. A locking mechanism according to claim 11 or 12, wherein said part of said steering column structure is a linear adjustment bracket.

14. A locking mechanism according to claim 13, wherein an underside of said linear adjustment bracket is provided with serrations, against which said wedging mechanism is arranged to wedge upon a crash.

15. A locking mechanism for locking an axially adjustable vehicle steering column in a crash situation, substantially as hereinbefore described with reference to the accompanying drawings.