GB1572965A

GB1572965A - Steering column assemblies

Info

Publication number: GB1572965A
Application number: GB737178A
Authority: GB
Original assignee: Ford Motor Co Ltd; Ford Motor Co
Current assignee: Ford Motor Co Ltd; Ford Motor Co
Priority date: 1978-02-23
Filing date: 1978-02-23
Publication date: 1980-08-06
Also published as: DE2904205A1; DE2904205C2; CA1130701A

Description

(54) STEERING COLUMN ASSEMBLIES (71) We, FORD MOTOR COM PANY LIMITED, of Eagle Way, Brentwood, Essex CM13 3BW, a British Company, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to by particularly described in and by the following statement:- This invention relates to steering column assemblies.

One conventional form of steering column assembly comprises two column sections one of which is axially adjustable relative to the other to allow the length of the steering column to be varied by the driver. These two sections are supported in a non-rotatable jacket which is attached to the vehicle body and which is movable with the adjustable column section. In order to reduce the risk of injury to a driver as a result of impact on the steering column, it has also been proposed to connect the jacket to the vehicle body by an element which deforms under impact loads to allow the steering column to collapse at a controlled rate so that the kinetic energy of the driver's body is absorbed in a gradual movement of the column. Where such elements are incorporated in adjustable steering columns the connection between the deformable element and the vehicle body must be slidable to accommodate the adjusnnent of the steering column. However, with such an arrangement there is a risk that the connection will exert insufficient force on the deformable element so that, under impact loads, the deformable element slides through the connection before deformation. As a result the amount of protection conferred on the driver by the deformable section will vary with the initial position of the steering column.

According to the present invention there is provided a steering column assembly comprising an upper rotatable column section adapted at one end to carry a steering wheel, a lower rotatable column section, adapted at one end for connection to a steering linkage and connected to the upper column section for rotation therewith about a common steering axis, the upper column section being axially movable relative to the lower column section, whereby the length of the assembly may be adjusted, a jacket surrounding and rotatably supporting the upper column section, a deformable member surrounding the jacket and connected thereto at one end, the deformable member being capable of altering its length under impact loads, a clamp extending around the deformable member towards the other end thereof, and a mounting bracket carrying the clamp and being deformable to allow the clamp to move under impact loads and to increase the damping force on the deformable member.

Preferably the clamp is connected to the bracket for rotation under impact loads about a transverse axis spaced from the steering axis.

The clamp will therefore rotate out of the plane which it normally occupies and exert a layer damping force on the deformable member. In order to allow this movement of the clamp, the bracket conveniently includes one or more abutments which engage with the clamp but which deflect under impact loads to allow the clamp to rotate.

Desirably the clamp is releasably mounted in the bracket for movement in a direction normal 0 the steering axis so that, in use, the driver can adjust the heigbt of the steering wheel as well as the length of the column.

The deformable member may be constructed to extend or to contract under impact loads.

In either case, the deformable section of the member is preferably in the form of a plurality of circurnferential corrugations. In the preferred embodiment of the invention, the de fonnable member includes a section which extends under impact loads to increase the length of the member. Such a member will usually be connected to the jacket towards the end of the jacket nearer the lower column section.

A preferred steering column assembly in accordance with rhe invention will now be described, by way of example only, with ref er- ence to the drawings in which: Figure 1 is a side piew of part of the assembly and Figure 2 is a plan of part of the assembly of Figure 2.

Referring to the drawings, the steering column assembly comprises an upper steering column section 1 which is splined at its upper end 2 for connection to a steering wheel 3, indicated in broken lines. The lower end 4 is connected to a coaxial lower steering column section 5 by means of a telescopic coupling, indicated schematically at 7. This coupling allows the upper column section 1 to move axially with respect to the lower column section 5, whereby the driver can vary the length of the column. The coupling 7 is of conventional construction and will be familiar to a person skilled in the art.

Details of its construction have therefore been omitted for the sake of brevity.

The lower end of the lower column drives a conventional steering linkage (not shown).

A jacket 6 rotatably supports the upper column section 1 in thrust bearings (not shown). A casting 8, incorporating a steering column lock, ignition switch and other controlls conventionally mounted on the steering column, is attached to the upper end 8 of the jacket 6. A flexible seal 9 seals the lower end of the jacket 6 to the upper column section 2.

A defotmable member in the form of a tube 10 surrounds the jacket 6 and is connected rigidly to the lower end of the jacket 6. The central and upper regions of rhe tube 10 are spaced from the jacket 6 by liners 11, 12. The tube 10 is provided with a deformable section 14 in the form of a series of circuferential con3gations. The upper end of the tube 10 terminates in an outwardly turned flange 13.

.A U-shaped clamp 15 extends around the upper region of the tube 10. Each limb of the clamp 15 terminates in a boss 16 through which a pivot pin 17 extends along an axis 18 transverse to the axis 19 of the steering column and spaced vertically therefrom. The ends of the pivot pin 17 pass through vertical slots 20 in opposed side walls 21 of a mounting bracket 22 which is fixed to the vehicle body.

A locking lever 25 is threaded onto one end of the pivot pin 17 by means of a bush 26 which includes an internal 2-start thread which engages with one side wall 21 of rhe mounting bracket 22. Rotation of the lever 25 in the direction of the arrow of Figure 1 causes the bush 26 to bear on the side wall 21 and thereby to exert a lateral force on the boss 16 of the clamp 15. As a result, a clamping force is applied to the tube 10. Since the pivot pin 17 is movable vertically in the slots 20, the driver can vary the height of the steering wheel 3.

The clamp 15 aburs with two pairs of transverse flanges 28, 29 on the side wails 21 which guide the clamp 15 in irs vertical movement.

The lower flanges 28 of each pair are formed by cutting part of the plate material from which the bracket 22 is made and bending them towards the rear of the steering column, i.e. towards the end of the column section 2 on which the steering wheel 3 is mounted.

In use, the driver releases the clamp 15 by means of the handle 25 and positions the steering wheel at an apiopriate distance from himself and at an appropriate height Under impact conditions, the load exerted on the steering wheel 3 by the driver's chest is transmitted to the jacket 6 and then to the tube 10.

The upper column section 2 slides into the lower column section 5. If the upper section 2 of the steering column has been depressed fully towards the bracket 22, the flange 13 on the upper end of the tube 10 will abut the edge of the damp 15 nearer to the steering wheel 3. On impact, the upper column section 2 slides into the lower section 5. The movement of the jacket 6 with the column 2 causes the tube 10 to be placed in tension, and the corrugated section 14 of the tube 2 to extend. The work required to extend this section is provided by the kinetic energy of the driver so that he is brought gradually to rest with a reduced risk of serious injury.

If the upper section 2 of the steering column has not been depressed fully towards the bracket 22, as illustrated in Figure 1, the force exerted on the tube 10 under impact conditions tends to rotate the clamp 15 about the axis of the pin 17. The flanges 28 offer relatively little resistance to this pivotal movement under such conditions and deflect so that the clamp 15 rotates relative to the jacket 6. The clamping force exerted on the tube 10 by the clamp 15 is therefore increased and any tendency of the tube 10 to slide through the clamp 15 is resisted. Consequently, on impact, the convoluted section 14 is extended by its full amount even when the flange 13 does not initially bear against the clamp 15. The driver is therefore protected to the same extent by the deformable tube 10 regardless of the initial setting of the steering colitnin in the bracket 22.

WHAT WE CLAIM IS: 1. A steering column assembly comprising an upper rotatable column section adapted at one end to carry a steering wheel, a lower rotatable column section, adapted at one end for connection to a steering linkage and connected to the upper column section for rotation therewith about a common steering axis, the upper column section being axially movable relative to the lower column section, whereby the length of the assembly may be adjusted, a jacket surrounding and rotatably supporting the upper column section, a deformable member surrounding the jacket and connected thereto at one end, the deformable member being capable of altering its length under impact loads, a clamp extending around the deformable member towards the other end thereof, and a mounting bracket carrying the damp and being deformable to allow the clamp to move under impact loads and to in

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

end 2 for connection to a steering wheel 3, indicated in broken lines. The lower end 4 is connected to a coaxial lower steering column section 5 by means of a telescopic coupling, indicated schematically at 7. This coupling allows the upper column section 1 to move axially with respect to the lower column section 5, whereby the driver can vary the length of the column. The coupling 7 is of conventional construction and will be familiar to a person skilled in the art.

Details of its construction have therefore been omitted for the sake of brevity.

The lower end of the lower column drives a conventional steering linkage (not shown).

A jacket 6 rotatably supports the upper column section 1 in thrust bearings (not shown). A casting 8, incorporating a steering column lock, ignition switch and other controlls conventionally mounted on the steering column, is attached to the upper end 8 of the jacket 6. A flexible seal 9 seals the lower end of the jacket 6 to the upper column section 2.

A defotmable member in the form of a tube

10 surrounds the jacket 6 and is connected rigidly to the lower end of the jacket 6. The central and upper regions of rhe tube 10 are spaced from the jacket 6 by liners 11, 12. The tube 10 is provided with a deformable section

14 in the form of a series of circuferential con3gations. The upper end of the tube 10 terminates in an outwardly turned flange 13.

.A U-shaped clamp 15 extends around the upper region of the tube 10. Each limb of the clamp 15 terminates in a boss 16 through which a pivot pin 17 extends along an axis 18 transverse to the axis 19 of the steering column and spaced vertically therefrom. The ends of the pivot pin 17 pass through vertical slots 20 in opposed side walls 21 of a mounting bracket 22 which is fixed to the vehicle body.

A locking lever 25 is threaded onto one end of the pivot pin 17 by means of a bush 26 which includes an internal 2-start thread which engages with one side wall 21 of rhe mounting bracket 22. Rotation of the lever 25 in the direction of the arrow of Figure 1 causes the bush 26 to bear on the side wall 21 and thereby to exert a lateral force on the boss 16 of the clamp 15. As a result, a clamping force is applied to the tube 10. Since the pivot pin 17 is movable vertically in the slots 20, the driver can vary the height of the steering wheel 3.

The clamp 15 aburs with two pairs of transverse flanges 28, 29 on the side wails 21 which guide the clamp 15 in irs vertical movement.

The lower flanges 28 of each pair are formed by cutting part of the plate material from which the bracket 22 is made and bending them towards the rear of the steering column, i.e. towards the end of the column section 2 on which the steering wheel 3 is mounted.

In use, the driver releases the clamp 15 by means of the handle 25 and positions the steering wheel at an apiopriate distance from himself and at an appropriate height Under impact conditions, the load exerted on the steering wheel 3 by the driver's chest is transmitted to the jacket 6 and then to the tube 10.

The upper column section 2 slides into the lower column section 5. If the upper section 2 of the steering column has been depressed fully towards the bracket 22, the flange 13 on the upper end of the tube 10 will abut the edge of the damp 15 nearer to the steering wheel 3. On impact, the upper column section 2 slides into the lower section 5. The movement of the jacket 6 with the column 2 causes the tube 10 to be placed in tension, and the corrugated section 14 of the tube 2 to extend. The work required to extend this section is provided by the kinetic energy of the driver so that he is brought gradually to rest with a reduced risk of serious injury.

If the upper section 2 of the steering column has not been depressed fully towards the bracket 22, as illustrated in Figure 1, the force exerted on the tube 10 under impact conditions tends to rotate the clamp 15 about the axis of the pin 17. The flanges 28 offer relatively little resistance to this pivotal movement under such conditions and deflect so that the clamp 15 rotates relative to the jacket 6. The clamping force exerted on the tube 10 by the clamp 15 is therefore increased and any tendency of the tube 10 to slide through the clamp 15 is resisted. Consequently, on impact, the convoluted section 14 is extended by its full amount even when the flange 13 does not initially bear against the clamp 15. The driver is therefore protected to the same extent by the deformable tube 10 regardless of the initial setting of the steering colitnin in the bracket 22.

WHAT WE CLAIM IS: 1. A steering column assembly comprising an upper rotatable column section adapted at one end to carry a steering wheel, a lower rotatable column section, adapted at one end for connection to a steering linkage and connected to the upper column section for rotation therewith about a common steering axis, the upper column section being axially movable relative to the lower column section, whereby the length of the assembly may be adjusted, a jacket surrounding and rotatably supporting the upper column section, a deformable member surrounding the jacket and connected thereto at one end, the deformable member being capable of altering its length under impact loads, a clamp extending around the deformable member towards the other end thereof, and a mounting bracket carrying the damp and being deformable to allow the clamp to move under impact loads and to in

crease the clamping force on the deformable member.
2. A steering column assembly according to claim 1 wherein the deformable member includes a section which extends under impact loads to increase the length of the deformable member, and the deformable member is connected to the jacket towards the end nearer the lower column section.
3. A steering column assembly according to claim 1 or claim 2 wherein the clamp is connected to the bracket for rotation under impact loads about a transverse axis spaced from the steering axis.
4. A steering column assembly according to claim 3 wherein the clamp engages an abutment between the transverse axis and the steering axis, winch deflects under impact load to permit rotation of the clamp.
5. A steering column assembly according to any one of claims 1 to 4 wherein the clamp is releasably mounted in the bracket for movement in a direction normal to the steering axis.
6. A steering column assembly according to any one of claims 1 to 5 wherein the deformable member includes deformable section which comprises a plurality of circumferential corrugations.
7. A steering column assembly substantially as hereinbefore described with reference to the drawings.