STEERING COLUMN CLAMPING MECHANISM

Abstract: A steering column clamping mechanism has bolt links (3, 5) interconnecting substantially parallel spaced-apart plates (1, 2) which basically form a rectangle and are so linked one to another that the rectangle can lozenge to a parallelogram. One of the connecting bolts (3) is mounted in a bracket (4) fixed to a chassis of a vehicle, the bracket (4) having a depending reaction plate (4A) against which an actuating member (10) can be urged to push the plate member (2) away from the reaction member (4A). Through the linkage, this causes the other plate member (1) to compress onto a steering column tube member (9) to clamp it between that plate (1) and the opposite side of the reaction plate (4A).

Description: STEERING COLUMN CLAMPING MECHANISM This invention relates to a steering column clamping mechanism. Known steering column clamping mechanisms tend to require rather close manufacturing tolerances and a typical type can be seen in EP-A-0 242 928. According to the present invention, there is provided a steering column clamping mechanism including a steering column tube member, a bracket and an actuating member, characterised by two spaced apart plate members, a first connecting link joining said two plate members, said bracket supporting said first connecting link, a second connecting link joining said two plate members remote from said first connecting link, a reaction plate between said two plate members, said steering column tube member being located between said first and second connecting links and located between and being clampable by one of said plate members and said reaction plate, and said actuating member being located to act to urge the other of said two plate members and the reaction plate apart thereby to cause said one plate member and said reaction plate to clamp said steering column tube member. Preferably, said reaction plate is joined to and forms part of said bracket. Said first connecting link can be in the form of a bolt member passing through said bracket and opposite ends being anchored to said first and second plate members. Said second connecting link can be a bolt member anchored at opposite ends to said first and second plate members, respectively. The respective connections between said two plate members and said first and second connecting links can be in the form of washers. The washers can be domed washers set in their plate members. When viewed on end, the plate members and their connecting links can be substantially in the form of a rectangle and the reaction plate can be substantially parallel, in an undamped state of the tube member, to the two plate members, which are themselves substantially parallel to one another. The steering column tube member in the region where it passes through the clamping mechanism can also be substantially rectangular in outer section. The actuating member can be in the form of a clamp bolt which is screwed in and out of the second plate member to extend the clamp bolt towards and away from the reaction plate. Other possible types of actuating member can be a cam arrangement. The actuating member may be a solenoid- operated actuating member. Provision can be made to limit travel of the steering column tube member and this can be achieved by providing a protrusion on the outside of the steering column tube member, which protrusion can ride in a slot provided in the reaction plate. 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 sectional end view of part of a steering column clamping mechanism, taken on the line X-X in Figure 2, and Figure 2 is a side view of the part of the clamping mechanism shown in Figure 1. The drawing shows part of a steering column clamping mechanism including two substantially parallel, spaced apart plate members 1, 2, a first connecting link 3 joining the two plate members 1 and 2, a bracket 4 supporting the connecting link 3 and a second connecting link 5 joining the two plate members 1, 2 remote from the first connecting link 3. The bracket 4 is fixed, e.g. to the chassis of a vehicle. In the form shown, each connecting link 3, 5 is in the form of a bolt, each passing through the two plate members 1 and 2 and being secured by bolt heads and nuts 6, 7, respectively. The bolt of the connecting link 3 passes through a bore 4B in the bracket 4. As shown, the connecting links and plate members produce a substantially rectangular form when viewed from the orientation given in Figure 1. However, provision is made at the respective connections between the plate members and connecting links so as to allow the two plate members to "lozenge" into a parallelogram. In other words, their direction of parallelism can be reorientated. This is achieved by providing domed washers 8 at each connection set into the respective plate members 1, 2. Depending from the bracket 4 between the plate members 1, 2 is a reaction plate 4A (forming part of the bracket 4) and a substantially rectangular steering column tube member 9 is located between the inside of the first plate member 1 and one side of the reaction plate 4A. The steering column tube member 9 is adjustable to allow the steering wheel to be adjusted to a desired position by the vehicle driver. An actuating member 10, in the present embodiment being in the form of a screw actuator, is provided to act between the opposite side of the reaction plate 4A to the tube member 9 and the second plate member 2. Figure 1 illustrates the situation in the substantially undamped state of the steering column tube member 9 and it will be seen that, by screwing the actuator 10 into the plate 2 by rotating its squared end 10A, a head 10B of the actuator 10 will be urged to the left to bear on the reaction plate 4A. By virtue of the provision of the washers 8 and since the reaction plate 4A is fixed, this will have the effect of urging the reaction plate 2 to the right as viewed in Figure 1 away from the reaction plate 4A and the leverage so provided will, through the connecting links 3 and 5 and the plate member 1, cause these members and links to lozenge, taking up any manufacturing tolerances, and causing the plate member 1 to be drawn in compression against the steering column tube member 9 to clamp it in position. It will be appreciated that the bore 4B through the bracket 4 through which the connecting link 3 passes should be oval or in some other way elongate to allow for free movement of the connecting link; this is especially true in the case envisaged where more than two connecting links are provided. As an example, in the present case, Figure 2 demonstrates that the bracket 4 is provided with six holes or bores 4B to allow for the use of two, four or six connecting links. It will be appreciated that because of the point contact of the head 10B of the clamped screw 10, the assembly is allowed to lozenge as described and the steering column tube member 9 is compressed between the bracket reaction plate 4A and the plate member 1. Any out of parallel condition of the steering column tube is compensated for by the fact that the plate member 1 can lozenge out of parallel to the reaction plate 4A. This lozenging effect also helps to widen the tolerance of the bolt length and nut position, as the plates themselves do not need to be exactly parallel. The reaction plate 4A is provided with a substantially rectangular opening 4C and this accommodates a protrusion on the outside of the steering column tube 9, the protrusion being in the form of a pin 11 with a soft covering which rides in the rectangular opening in order to limit steering column travel, the soft covering giving a soft feel when reaching the end positions in the opening 4C.

Claims: CLAIMS ; 1. A steering column clamping mechanism including a steering column tube member (9) , a bracket (4) and an actuating member (10) , characterised by two spaced apart plate members (1, 2) , a first connecting link (3) joining said two plate members, said bracket (4) supporting said first connecting link, a second connecting link (5) joining said two plate members remote from said first connecting link, a reaction plate (4A) between said two plate members (1, 2) , said steering column tube member (9) being located between said first and second connecting links and located between and being clampable by one of said plate members and said reaction plate, and said actuating member (10) being located to act to urge the other of said two plate members and the reaction plate apart thereby to cause said one plate member and said reaction plate to clamp said steering column tube member. 2. A clamping mechanism according to claim 1, wherein said reaction plate (4A) is joined to and forms part of said bracket (4) . 3. A clamping mechanism according to claim 1 or 2, wherein said first connecting link is in the form of a bolt member (3) passing through said bracket (4) and opposite ends being anchored to said first and second plate members (1, 2). 4. A clamping mechanism according to claim 1, 2 or 3, wherein said second connecting link is a bolt member (5) anchored at opposite ends to said first and second plate members (1, 2) , respectively. 5. A clamping mechanism according to any one of the preceding claims, wherein the respective connections between said two plate members (1, 2) and said first and second connecting links (4, 5) are in the form of washers (8). 6. A clamping mechanism according to claim 5, wherein the washers are domed washers (8) set in their plate members (1, 2). 7. A clamping mechanism according to any one of the preceding claims, wherein, when viewed on end, said plate members (1, 2) and their connecting links (4, 5) are substantially in the form of a rectangle and said reaction plate (4A) is substantially parallel, in an undamped state of the tube member (9) , to the two plate members, which are also substantially parallel to one another. 8. A clamping mechanism according to any one of the preceding claims, wherein the steering column tube member (9) in the region where it passes through the clamping mechanism is substantially rectangular in outer section. 9. A clamping mechanism according to any one of the preceding claims, wherein said actuating member is in the form of a clamp bolt (10) which is threadably engaged in said second plate member (2) to extend the clamp bolt towards and away from said reaction plate (4A) . 10. A clamping mechanism according to any one of claims 1 to 8, wherein said actuating member is a cam arrangement. 11. A clamping mechanism according to any one of the preceding claims, wherein said actuating member is a solenoid-operated actuating member. 12. A mechanism according to any one of the preceding claims, wherein a protrusion (11) is provided on the outside of said steering column tube member (9) , which protrusion rides in a slot (4C) provided in said reaction plate (4A) to limit travel of the steering column tube member. 13. A vehicle incorporating a steering column clamping mechanism according to any one of the preceding claims. 14. A vehicle according to claim 13, wherein said bracket is attached to a chassis of the vehicle.

Inventors: BAKER STEPHEN JOHN, BOBBITT JOHN THOMAS III, BAKER, STEPHEN, JOHN, BOBBITT, JOHN, THOMAS, III
Applicants: NASTECH EUROP LTD, NASTECH EUROPE LIMITED
Application year: 1996
Main classification: B62D1
IPC codes: B62D1, F16B2