GB2299844A - Telescopic lever - Google Patents

Abstract

A telescopic lever 12 may be used, for example, to operate a steering column clamping system. The lever has telescopic sections 12a and 12b which are held in their extended position against spring bias by a detent 25 which automatically locks them in an extended position when the lever is extended, and which is automatically released to allow the lever to retract when the lever is pushed back into a home position.

Description

LEVER This invention relates to a lever, particularly a telescopically extendable lever for use in operating a steering column lock on a motor vehicle.

Steering column locks on motor vehicles often make use of a lever which has to be turned to lock or to release a clamping mechanism which holds the steering column in any desired position relative to the vehicle bodywork.

Because the clamping loads need to be high to ensure that the column does not move from the position at which it has been set, a long lever is needed to apply the necessary force. However, it is undesirable to have a long lever in the passenger compartment, and it is known to make the lever telescopic so that it can be extended when it is in use, and retracted when it is out of use.

According to the present invention, there is provided a lever comprising a lever arm mounted for rotation on a bracket, wherein the lever arm has telescopic sections which can be extended to increase the length of the arm, a spring for biasing the telescopic sections to a retracted position, and a detent arranged to lock the arm in the extended position, the bracket having an abutment surface which, in one position of the lever arm, disengages the detent to allow the spring to automatically retract the telescopic sections.

If the telescopic sections are spring-biased to the retracted position, it is desirable to be able to secure the sections in their extended position during operation, rather than requiring the user to exert a force holding the sections extended at the same time as applying a turning force.

There are preferably two telescopic sections, and the sections may be associated with a tension spring located inside the telescopic sect ions which biases the sections to a retracted position. This spring has to be stretched to extend the sections.

The detent is preferably spring-loaded so that it automatically moves into a locking position when the sections are extended and the lever is moved away from the abutment surface of the bracket. Returning the lever to its position against the abutment surface results in the abutment surface overcoming the spring-loading to lift the detent out of the locked position.

The end of the lever remote from the bracket preferably has a grip portion thereon.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a lever arm and bracket: Figure 2 shows the lever arm of Figure 1 in an extended position; Figure 3 is a view, partly exploded, of a lever arm in accordance with the invention; Figures 4, 5 and 6 show sequential operating stages; Figure 7 illustrates a second embodiment of lever arm in accordance with the invention; and Figure 8 illustrates a third embodiment of lever arm in accordance with the invention.

Figure 1 shows part of a steering column mounting bracket 10 with a lever arm 12 mounted for rotation thereon.

Turning the lever on 12 about the axis of a spindle 14 locks or releases a clamping block 60 to free or to clamp a steering column, in a known manner.

The lever arm 12 has a shaped grip portion 18 at its lower end. As can be seen in Figure 2, the lever arm has a first section 12a and a second section 12b, these two sect ions being telescopic and housing within themselves a tension spring 20 anchored at one end (by a cross-bar 22) to the section 12a and at the other end (not shown) to the section 12b. When the arm 12 is extended to the position shown in Figure 2, the spring 20 is stretched and if the section 12b is then released, the spring 20 will cause the two sections to retract to the position shown in Figure 1 where the overall length of the lever arm 12 is short.

In order to lock the sect ions in their extended position, a detent is provided which is shown in Figure 3. The detent takes the form of a leaf spring 24 with a tooth 25 and a lateral projection 26. The spring has arcuate arms 20a which embrace the top part of the outer section 12a and are attached thereto by a pin (which may be the pin 22) engaging through the holes 30, 32. At the top of the spring 24 there is a leaf 34 with an end region 36 which lies against a shoulder 30a on a mounting portion 40 of the lever arm.

The outer tubular section 12a has an aperture 42 which registers with the tooth 25 and through which the tooth will normally project. The inner section 12b also has a similar aperture 44, but at a point along the length of the section which will register with the aperture 42 when the lever arm is extended. Thus, when the lever arm is pulled out, the tooth 25 will engage through the aperture 42 and through the corresponding aperture in the inner section 12b, to hold the sections in their extended position. This locking action will take place automatically, as a result of the spring energy stored in the leaf spring 24, as soon as the aperture 44 in the inner section 12b comes into line with the aperture 42 in the section 12a.

To release the detent, a force is applied to the lateral projection 26 which causes the tooth 25 to move in a radial direction so that it is lifted out of the aperture in the inner section 12b, and when this happens, the spring 20 will cause the two sections to retract to the position shown in Figure 3.

In order to ensure that the aperture 44 in the inner section 12b remains in the correct circumferential position, there will be a keying arrangement between the inner and outer sections 12a, 12b to prevent relative rotation of these sections.

As an alternative to an aperture 44 in the inner section, the inner section could have an annular groove for receiving the tooth 25. Another alternative would be for the tooth to engage behind the end of the inner section, in which case no special feature is required on the inner section to receive the tooth. In both these alternatives, it is not necessary to prevent relative rotation of the sections.

The lateral projection 26 is moved as described above by contact with the mounting bracket 10 when the lever arm 12 is returned to its starting position.

The various stages in operation are illustrated with reference to Figures 4, 5 and 6.

Figure 4 shows the normal, rest position of the lever arm.

Sections 12a, 12b are retracted. The arm is in a generally vertical position and the projection 26 (not shown in these figures) is in contact with an abutment surface of the mounting bracket 10 such that the tooth 25 is lifted away from the apertures in the sections.

Figure 5 shows the lever just at the start of movement.

As soon as the lever is moved away from its vertical position, the projection 26 moves away from the bracket 10 and the tooth 25 comes to line through the aperture 42 on the surface of the inner section 12b.

Next, the lever is extended by pulling out the inner section until the aperture 44 in the inner section registers with the aperture 42 and in this position, the tooth 25 drops through both apertures. The force of the spring 20 trying to retract the two sections is then absorbed by the tooth which prevents retraction.

The extended lever can then be used to operate the steering column clamp. However, as soon as the lever is moved back to its rest position (as shown in Figure 4) the contact between the projection 26 and the bracket 10 will cause the tooth 25 to be lifted out of the apertures so that the spring 20 again causes the lever to be retracted.

Figure 7 shows an embodiment in which the external spring 24 is replaced by a moulded in spring 124. This spring has a lateral projection 126 which will make contact with a surface on the bracket 10 in a similar way to the lateral projection 26. A tooth 125 is moulded in as part of the spring 124.

Figure 8 shows another arrangement in which a shaped wire spring 224 provides the retention of the tubular extension. This detent has a bar 225 which will lie across the aperture 42 in the outer section 12a, taking up the position of a chord of a circle. The circumferential extent of the apertures 42, 44 will be sufficient to allow the bar 225 to have sufficient radial extension to engage both the apertures. The bent wire ends in a lateral projection 226 which will engage with a surface on the bracket 10 in the same way as the projections 26, 126.

The invention thus enables the user of the lever to pull it out and have it automatically retained in the extended position while it is being used, with the lever automatically returning to its retracted position when it is pivoted back to the home position.

Claims (6)

Claims

1. A lever comprising a lever arm mounted for rotation on a bracket, wherein the lever arm has telescopic sect ions which can be extended to increase the length of the arm, a spring for biasing the telescopic sections to a retracted position, and a detent arranged to lock the arm in the extended position, the bracket having an abutment surface which, in one position of the lever arm, disengages the detent to allow the spring to automatically retract the telescopic sections.

2. A lever as claimed in Claim 1, wherein there are two telescopic sections, and the sections are associated with a tension spring located inside the telescopic sections which biases the sections to a retracted position.

3. A lever as claimed in Claim 1 or Claim 2, wherein the detent is spring-loaded so that it automatically moves into a locking position when the sect ions are extended and the lever is moved away from the abutment surface of the bracket.

4. A lever as claimed in any preceding claim, wherein return of the lever to its position against the abutment surface results in the abutment surface overcoming the spring-loading to lift the detent out of the locked position.

5. A lever as claimed in any preceding claim, wherein the end of the lever remote from the bracket has a grip portion thereon.

6. A lever substantially as herein described with reference to the accompanying drawings.