GB2352285A

GB2352285A - Clamping device for a steering column

Info

Publication number: GB2352285A
Application number: GB9916922A
Authority: GB
Inventors: Sebastien Kluska; Eric Lamour; Stephane Thomas
Original assignee: Delphi Technologies Inc
Current assignee: Delphi Technologies Inc
Priority date: 1999-07-19
Filing date: 1999-07-19
Publication date: 2001-01-24
Also published as: GB9916922D0

Abstract

A clamping device 10 for the steering column of a motor vehicle comprises a first bracket 12 having a pair of spaced arms 24; a second bracket 14 having a pair of spaced arms 18, each arm of the second bracket being positioned adjacent to, and inside, one of the arms of the first bracket; and a clamping mechanism including a first friction surface 32 on one of the arms of the second bracket between adjacent arms of the first and second bracket, and a cam member 51 extending through an aperture in the adjacent arm of the first bracket. The cam member has a second friction surface 54 engageable with the first friction surface in a clamp position of the clamping mechanism, and a cam surface 52 directed away from the first friction surface. A pivotable member 42 has a cam surface 60 in engagement with the cam surface 52 on the cam member, and a spring 56 acts on the cam member to bias the friction surfaces away from one another in a release position of the clamping mechanism.

Description

2352285 CLAMPING DEVICE FOR A STEERING COLUMN

Technical Field

The present invention relates to a clamping device for the steering column of a motor vehicle, and in particular to a clamping device which allows the steering column to rake and telescope relative to the vehicle body.

Backaround of the Invention

It is known to provide a clamping device for a steering column which allows the steering column to rake and telescope relative to the vehicle body. The clamping device generally comprises a first bracket which is secured to the vehicle body, and a second bracket which is secured to the steering column. The first and second brackets are secured together by a clamping mechanism including a bolt and a nut, with the bolt passing through aligned apertures in the first and second brackets. The apertures in the first bracket are shaped to allow the steering column to have a rake movement (height adjustment or tilt) when the clamping mechanism is loose. The apertures in the second bracket are shaped to allow the steering column to telescope (move in an axial direction) when the clamping mechanism is loose.

Summary of the Invention

The object of the present invention is to provide an improvement to this previously known arrangement.

A clamping device in accordance with the present invention for the steering column of a motor vehicle, comprises a first bracket having a pair of spaced arms; a second bracket having a pair of spaced arms, each arm of the second bracket being positioned adjacent to, and inside, one of the arms of the first bracket; and a clamping mechanism including a first friction surface on one of the arms of the second bracket between adjacent arms of the first 2 and second bracket; a cam member extending through an aperture in the adjacent arm of the first bracket, the cam member having a second friction surface engageable with the first friction surface in a clamp position of the clamping mechanism, and a cam surface directed away from the first friction surface; a pivotable member having a cam surface in engagement with the cam surface on the cam member and rotatable relative to the cam member; and a spring acting on the cam member to bias the friction surfaces away from one another in a release position of the clamping mechanism.

The present invention provides a clamping device in which the holding load or torque of the clamping mechanism is increased simply and cheaply.

Brief Description of the Drawings

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is an exploded view of a clamping device in accordance with the present invention; Figure 2 is a cross-sectional view of the clamping device of Figure 1; and Figure 3 is an enlarged perspective view of the friction surface on the second bracket of clamping device of Figures 1 and 2.

Description of the Preferred Embodiment

Referring to the drawings, the clamping device 10 of the present invention is for use with a steering column (not shown) of a motor vehicle. The clamping device 10 is such as to allow the steering column to rake and/or telescope relative to the vehicle body (not shown) on which the column is mounted.

The clamping device 10 comprises a first bracket 12 which, in use, is secured to the vehicle body in any suitable arrangement; and a second bracket 14 which is secured (in any suitable manner) to a tubular jacket 16. In 3 use, the jacket 16 surrounds, and is secured to, a portion of the steering column. The jacket 16 has a longitudinal axis A.

The second bracket 14 includes a pair of spaced arms 18 which are positioned on either side of the jacket 16 and are preferably connected by a base member 20. The arms 18 each have a free edge 22 remote from the base member 20 and extending in a direction substantially parallel to the axis A.

The first bracket 12 includes a pair of spaced arms 24, each of which is positioned adjacent one of the arms 18 of the second bracket 14. The arms 24 of the first bracket 12 are preferably connected by a bridge member 26. Each arm 24 of the first bracket 12 has an internal ledge or channel 28 formed thereon which opens towards and/or faces the bridge member 26. The free edges 22 of the arms 18 of the second bracket 14 make a sliding fit on the ledges or channels 28 formed on the arms 24 of the first bracket 12.

A clamping mechanism 30 is used to releasably clamp the first and second brackets 12,14. The clamping mechanism 30 comprises a first friction surface 32 which is positioned on the outer surface 34 of one of the arms 18 of the second bracket 14 between the adjacent arms 24,18 of the first and second brackets 12,14. The adjacent arm 24 of the first bracket 12 has an aperture 36 formed therein adjacent the first friction surface 32. The first friction surface 32 comprises rows 38 of pyramid-shaped or cone-shaped protuberances 40, with the protuberances in one row being offset from the protuberances in the next adjacent row.

The clamping mechanism 30 ftirther comprises a lever 42 which can pivot about an axis B which extends substantially perpendicular to, and passes through, the axis A. The aperture 36 on the arm 24 of the first bracket 12 is centred on the pivot axis B. The lever 42 has a radially outwardly extending annular shoulder 44 which is centred on the pivot axis B. A cylindrical member 46 is secured to the arm 24 of the first bracket 12 around the aperture 36 and is centred on the pivot axis B. The cylindrical member 46, at its end remote from the first bracket 12, has a radially inwardly extending shoulder 48. The shoulder 44 on the lever 42 is positioned inside, 4 and in engagement with the shoulder 48 of, the cylindrical member 46. A cam member 50 is positioned inside the cylindrical member 46 and has a part 51 which extends through the aperture 36. The part 51 and the aperture 36 are preferably substantially rectangular and sized to substantially prevent rotation of the cam member 50 about the pivot axis B. The cam member 50 has a first surface 52 directed towards the lever 42, and a second surface 54 (on part 51) directed towards the first friction surface 32. A coil spring 56 is positioned inside the cylindrical member 46 in engagement with the cam member 50 and the first bracket 12 to bias the cam member towards the lever 42. The second surface 54 of the earn member 50 is a (second) friction surface which is substantially identical to the first friction surface 32 and comprises rows of pyramid-shaped or cone-shaped protuberances 58, with the protuberances in one row being offset from the protuberances in the next adjacent row. The first surface 52 of the cam member 50 is a cam surface, and the adjacent surface 60 on the lever 42 is a corresponding cam surface.

The cam surfaces 52, 60 are in substantially continuous engagement due to the bias of the coil spring 56.

In the clamped position of the clamping mechanism 30, as shown in Figure 2, the protuberances 58 on the second friction surface 54 are located between the protuberances 40 on the first friction surface 32 to secure the first bracket 12 relative to the second bracket.

In order to move the clamping mechanism 30 to a released position, the lever 42 is rotated in a first direction about the pivot axis B. Such rotation of the lever 42 rotates the cam surface 60 thereon, about the pivot axis B, relative to the cam surface 52 on the cam member 50. During movement of the lever 42, the cam member 50 is prevented from rotating about the pivot axis B due to the shapes of the part 51 and aperture 36. As the cam surfaces 52,60 rotate relative to one another, the coil spring 56 acts on the cam member 50 to move the cam member along the pivot axis B towards the shoulder 48 on the cylindrical member 46 such that the protuberances 58 on the second friction surface 54 become disengaged from the protuberances on the first friction surface 32. In the released position of the clamping mechanism 30, the second bracket 14 is capable of telescopic and/or rake movement relative to the first bracket 12. Stops 100, 10 1 are formed on the inner surfaces of the arms 24 of the first bracket 12 to prevent excessive 5 telescope and/or rake movement.

In order to move the clamping mechanism 30 back to the clamping position, the lever 42 is rotated in the opposite direction to the first direction about the pivot axis B. Such action has the reverse effect to that described above during release, and the cam member 50 moves towards the second bracket 14 to bring the protuberances 40,58 backs into engagement.

The shape of the protuberances 40,58 is such as to provide a form of selfcentring during clamping to ensure that the protuberances 58 on the second friction surface 52 extend fully in between the protuberances 40 on the first friction surface in order to provide the required clamping force between the 15 first and second brackets 12,14.

The present invention provides a clamping device with a clamping mechanism which is simple and easy to assemble, and which is capable of providing an increase in clamping force over previously known arrangements. The clamping force can be altered by changing the profile 20 and/or the dimensions of the protuberances.

As an alternative to the shape of the part 51 and the aperture 36, pegs or any other suitable means may be used to substantially prevent rotation of the cam member 50 about the pivot axis B. The first friction surface 32 may be formed on a plate member (as shown in Figure 3) which is 25 secured to the arm 18, or may be integrally formed on the arm 18.

6

Claims

1. A clamping device for the steering column of a motor vehicle comprising a first bracket having a pair of spaced arms; a second bracket having a pair of spaced arms, each arm of the second bracket being positioned adjacent to, and inside, one of the arms of the first bracket; and a clamping mechanism including a first friction surface on one of the arms of the second bracket between adjacent arms of the first and second bracket; a cam member extending through an aperture in the adjacent arm of the first bracket, the cam member having a second friction surface engageable with the first friction surface in a clamp position of the clamping mechanism, and a cam surface directed away from the first friction surface; a pivotable member having a cam surface in engagement with the cam surface on the cam member and rotatable relative to the cam member; and a spring acting on the cam member to bias the friction surfaces away from one another in a release position of the clamping mechanism.

2. A clamping device as claimed in Claim 1, wherein the friction surfaces each comprise rows of protuberances, the protuberances in one row being offset from the protuberances in the next adjacent row.

3. A clamping device as claimed in Claim 2, wherein the protuberances are pyramid-shaped or cone-shaped.

4. A clamping device as claimed in any one of Claims I to 3, wherein the first bracket is securable to the vehicle and the second bracket is securable to the steering column.

5. A clamping device as claimed in any one of Claims 1 to 4, further comprising a cylindrical member secured to the adjacent arm of the first bracket around the aperture therein, the cam surfaces on the cam member 7 and the pivotable member, and the spring being surrounded by the cylindrical member.

6. A clamping device as claimed in Claim 5, wherein the pivotable member has a radially outwardly extending shoulder positioned inside the cylindrical member in engagement with a radially inwardly extending shoulder on the cylindrical member to retain the cam surface on the pivotable member inside the cylindrical member.

7. A clamping device as claimed in any one of Claims I to 6, wherein the cam member has a part extending through the aperture in the adjacent arm of the first bracket, the part and the aperture being substantially rectangular and sized to substantially prevent rotation of the cam member relative to the aperture.

8. A clamping device as claimed in any one of Claims 1 to 7, wherein the pivotable member is a lever.

9. A clamping device substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.