FR2521652A1 - Flexible clamp for vehicle steering column - has one jaw thickened, with threaded hole to receive clamp bolt - Google Patents

Abstract

The clamp has an open circular section (1) with a jaw (4) extending from either side. The clamp has a back plate (2) with holes (3) for mounting onto the vehicle. One jaw (4a) has a plain hole through which the clamping bolt passes. The other jaw (4b) has a tapped hole formed initially by drilling a pilot hole in the jaw then opening the hole by displacing the material and rolling it over to provide an increased thickness to the jaw. In this way a nut is not necessary for the clamping bolt.

Description

The invention relates to a method of manufacturing an elastic coupling collar and more particularly to the method of tightening said collar.

The elastic coupling collars noted those intended for the steering columns of motor vehicles essentially comprise an open ring with rounded profile intended to be fitted on the column, ring whose jaw-forming ends constitute the clamping part and are provided with this effect of two holes for the passage of the screw-nut assembly.

This classic coupling collar system usually uses a screw and a nut resting against the clamping piece. For certain specific applications, the use of a nut is not without problems even if only in terms of space; it requires that the bearing face be flat and of sufficient size for the pressure of the nut to be exerted in a uniform manner or else a washer must be inserted there, see a serrated washer.

In addition, the nut and the collar must be accessible for tightening, so the ends of the ring must be sufficiently dimensioned so that when tightening, one is not bothered by the body of the collar. Otherwise, tightening will be ensured using the screw, but the nut should then be locked.

To avoid these drawbacks, we sought to make the nut integral with the part by embedding it in a form provided for this purpose, which makes it easier to assemble and tighten the collar. But this solution with captive nut is obviously more expensive because apart from the realization of the orifices in the collar, it is necessary to provide in addition to the screw, j & nut, its locking system, and a bore
particular of the ring.

We then tend to realize systems without nuts, thanks to a tapping performed directly in one of the orifices of the clamping jaw. But the torque that can be exerted on the part is obviously much less than with a nut as far as the thread is formed in a genFra- Ieient orifice of small thickness.

The invention makes it possible to avoid this drawback in that it makes it possible to produce a weeping collar without a tightening nut but having a much higher resistance than conventional systems.

The method according to the invention essentially consists in boring a pilot hole in a jaw of the clamping piece, in giving the orifice thus formed a larger diameter by pushing the metal towards the outside.
laughing to obtain a circular excess thickness of metal at this level, then tapping said hole as well as the excess thickness, the thread being thus generally obtained over a greater thickness of metal.

The characteristics and advantages of the invention will emerge from the description which follows of an embodiment with reference to the appended drawings which represent FIG. 1: a front view of an elastic coupling collar.

Figure 2: a side view in partial section along
AA 'of figure 1.

The elastic coupling collar shown, for
steering columns for motor vehicles,
shape of an open ring I with rounded profile fitted
on either side of fixing lugs 2 themselves pierced with holes 3 for the passage of fixing screws. The ring intended to be fitted onto a steering column ends in two jaws 4 which are clamped on the column. For this purpose a first orifice 5 is provided on a jaw 4a for the passage of a clamping screw.

The other jaw 4b is also provided with a tap orifice 6 produced in the following manner. A small diameter pre-hole is made in alignment with the orifice 5, then this orifice is enlarged by pushing the metal from the inside of the ring towards the outside, the driven metal forming a circular extra thickness 7 around the orifice 6 thus realized. It then remains to tap this orifice and this additional thickness so as to obtain a thread on a # greater thickness of metal. Therefore the tightening obtained by the screw introduced by the orifice 5, in engagement with the thread of the orifice 6 is much more resistant than if it "only hung" the original thickness of the jaw 4. The locking the screw after tightening is obtained by conventional means such as punching the ends.

Thanks to this process, it is possible to achieve an effective tightening, without nut, being able to support a significant torque even in difficult accessibility conditions.

The invention is not limited to the example of embodiment described but on the contrary encompasses all the constructive variants thereof.

Claims (1)

CLAIMS 1e) Method of manufacturing an elastic coupling collar comprising an open ring whose ends forming the jaw constitute the clamping piece and are each provided with an orifice, one of which is threaded for the attachment of the screw clamping, characterized by the fact that the orifice (6) provided on one of the jaws (4b) is obtained from a pilot hole by metal discharge towards the outside to obtain a circular excess thickness (7) of metal and by the fact that one taps said orifice in order to obtain a thread both on the thickness of the rachor and the additional thickness thus obtained.  20) Elastic coupling collar according to the method of  claim 1.