GB2116416A - Self-locking belt reeling mechanisms - Google Patents

Abstract

In a self-locking belt reeling mechanism, particularly for safety belts for motor vehicles, having a vehicle-sensitive locking system constructed as a ball or pendulum sensor, wherein the element sensitive to acceleration, namely the ball or pendulum, throws out a lever which engages in stop locations in a disc which locks the belt winding spindle when the sensor is activated, flexible material is provided in the region of the lever for noise attenuation, the noise problem is in the region of the tip (17) of the lever (14). Thus, when subjected to jolting, the tip of the lever may clatter over the toothed periphery of the disc (18) which causes blocking of the belt winding spindle and this may be a nuisance. To solve this problem, an annular attenuating member consisting of flexible material (22, 27), the periphery of which is struck by the lever (14, 17, 24) as it moves, is mounted on a component (18, 25) adjacent to the lever. <IMAGE>

Description

SPECIFICATION Self-locking belt reeling mechanisms The invention relates to a self-locking belt reeling mechanism, particularly although not exclusively for safety belts for motor vehicles of the kind having a vehicle-sensitive locking means in the form of a ball or pendulum sensor, wherein the ball or pendulum actuates a lever which engages abutments provided in a disc to lock the belt winding spindle when the sensor is activated.

In a belt reeling mechanism of this kind known from being in general use, the tip of the lever which can be deflected by the element sensitive to acceleration is provided with a coating of flexible plastics for noise attenuation and indeed this coating is a shaped component in the form of cap which itself forms the operative tip of the lever.

The disadvantage of this is the comparatively great inaccuracy, whereas it is precisely at this point of the automatic system that minimum tolerances are necessary and prescribed. A further disadvantage is that the cap-shaped member requires a special tool. Finally, the known noise attenuation system cannot be used as an added modification since this would affect the weight on the lever and this would in turn influence the g value.

The aim of the invention is to provide a belt reeling mechanism of the kind described wherein noise attenuation is achieved at the sensor without having to modify the sensor as such in its construction and method of operation.

According to the invention there is provided a self-locking belt reeling mechanism of the kind described wherein a noise attenuating element of flexible material, the periphery of which is engaged by the lever as it moves, is mounted on a component adjacent to the lever.

The invention has the advantage that the attenuation element can be formed as a separate component from the sensitive sensor components, with the result that the sensor components do not have to be modified but rather their precision can be guaranteed without reference to the noiseattenuating measures. However, with the invention, it is advantageously possible to switch to reasonable sizes for the noise-attenuating members, since, by contrast with the prior art, narrow tolerances are not required. Finally, there is a considerable reduction in the cost involved in achieving the desired objective.

In order that the invention may be understood two embodiments thereof will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 shows in side view a ball sensor and a portion of a toothed disc for initiating the locking of the belt winding spindle with the lever of the sensor in the locking position, Fig. 2 is a view of a radial section through the disc on the line 11-Il in Fig. 1, Fig. 3 is a side view corresponding to Fig. 1 in which the lever of the sensor is out of the locking position, Fig. 4 shows a view similar to Fig. 3 of a second embodiment i.e. with the locking lever out of the locking position.

Fig. 5 is a view similar to Fig. 4 but with the lever in the locking position.

In the first embodiment shown in Figures 1 to 3, a ball sensor 10 is fixed in the usual way to a side wall 11 of a belt reeling housing (the remainder of which is not shown). The belt sensor consists of four components, namely a ball dish 12, a ball 13, a lever 14 and a lever spindle 1 5.

The ball dish 12 has two upright legs 1 6 between which the lever spindle 1 5 extends. The lever 1 4 is pivotally mounted at one end, whilst in its central part it abuts on the ball 13. When the ball 13 moves out of its central position in the dish 12 by rolling to one side, under the effect of forces of acceleration acting on the apparatus as a whole, the lever 14 is raised. The central position of the ball 13 is shown in Figure 3; Figure 1 shows the position of the components of the ball sensor 10 when the ball 1 3 has shifted to the right.

The lever 14 has a bent tip 17 which is intended to engage in the toothed rim of a disc 1 8 with teeth 1 9 which is mounted close beside the ball sensor 10, so as to secure the disc 1 8 against further rotation about a spindle 20. The spindle 20 is, at the same time, the central axis of the belt winding spindle (not shown). The disc 18 is appropriately connected to a locking member (again not shown) which blocks the belt winding spindle in the event of any forces of acceleration above a certain limit which could endanger the wearer of the belt, for example in an accident. The disc 18 with teeth 1 9 simultaneously acts as an inertial member for the belt-sensitive locking system in some types of belt reeling mechanisms and is therefore also known as an inertia disc.

Since the lever 14, 1 7 is both lightweight in itself and is also lightly mounted on the spindle 1 5 and the spacing between the tip 1 7 of the lever and the disc 1 8 is only of the order of 1 mm, some noise, admittedly quiet but nevertheless unpleasant, may be produced if for any reason, e.g. poor road surface, vibratory frequencies are transmitted to the sensor 10. Then the tip 1 7 of the lever rapidly hits the periphery of the disc 1 8 repeatedly and produces a clattering noise. This may also happen if the ball 13 is made to jump in its dish 12. The material of the lever 14, 17 and disc 18, which will necessarily be solid, generally plastics with a smooth, hard surface, adds to the noise.

To remedy this, a thin rubber ring 22 which is circular in cross section is mounted in a circumferential groove 21 in the disc 18 (Fig. 2); this rubber ring 22 projects slightly beyond the periphery of the disc 1 8 so that the tip 1 7 of the lever cannot hit the material of the disc 1 8 between the teeth 1 9 but makes contact with the rubber ring 22, with the result that the noise is reduced accordingly. An essential point is that the teeth 1 9 must project outwardly beyond the rubber ring 22 far enough to ensure that the tip 1 7 of the lever engages securely in the teeth 1 9 and thus causes blocking of the disc 18.

As can be seen from Figure 2, the groove 21 for the rubber ring 22 is located outside the circumferential row of teeth 19, thus simplifying the mounting of the rubber ring 22 during production. The tip 1 7 of the lever is so wide that it engages over both the rubber ring 22 and also the teeth 1 9. This ensures both noise attenuation and also the locking action in this region at every point on the periphery of the disc 1 8.

Figures 4 and 5 show a second embodiment which is basically similar to the first. Here, too, there is a ball sensor 10 with a ball dish 12, ball 13 and lever 14 with lever tip 17 which is intended for engagement in teeth 1 9 in an inertia disc 1 8. The lever 14 is mounted between housing legs 16 on a lever spindle 1 5. The lever in this embodiment is a two-armed lever with lever arms 23, 24, the arm 23 being mounted on the ball 13 and deflected by this ball in the event of any changes in acceleration, with the result that the tip 17 of the lever pivots in the opposite direction. In this embodiment, too, there is a possibility of clattering noises, as a result of the design, as the tip 17 of the lever may make contact with the base of the teeth on the periphery of the disc 1 8.

To prevent noises of this kind, the ball dish 12 of the sensor 10 is, in this case, provided with an attachment 25 which has a projecting portion 26 so as to form an undercut on which a rubber ring 27 of circular cross section abuts in such a way that the rubber ring 27 projects partly over the projecting portion 26. Since the attachment 25 in the pivot region of the arm 24 of the lever 14 is located at such a point that the lever arm 24 comes to abut on the rubber ring 27 before the tip 17 of the lever can make contact with the periphery of the disc 18, corresponding noise is prevented. The essential point is that the teeth 1 9 must project beyond the lowest position of the lever tip 1 7 to such an extent that the disc 1 8 is reliably blocked by the lever 14.

By virtue of their flexibility, the rubber rings 22, 27 can be inserted in their mountings rapidly and without any appreciable use of force, which is important for the economics of the manufacturing process. The service life of the rubber rings can be extended considerably by the use of a light-proof cover which thus prevents ageing. Rubber rings of various dimensions are already available to fit the various types of belt reeling mechanisms.

In the embodiment shown in Figures 4 and 5, it is also possible to replace the rubber ring 27 by an annular or arcuate shaped part serving the same purpose, consisting of solidified flexible material applied in liquid or paste form, for example by dipping the attachment 25 on the sensor 10 into a bath of the material in question.

The features of the object of the application which are disclosed in the specification, claims, drawings, and abstract may be essential to the realisation of the various embodiments of the invention both individually and in any desired combination with one another.

Claims (11)

1. A self-locking belt reeling mechanism having a vehicle-sensitive locking means in the form of a ball or pendulum sensor, wherein the ball or pendulum actuates a lever which engages abutments provided in a disc to lock the belt winding spindle when the sensor is activated, wherein a noise attenuating element of flexible material the periphery of which is engaged by the lever as it moves, is mounted on a component adjacent to the lever.

2. A belt reeling mechanism as claimed in claim 1 wherein the attenuating element is annular and circular in cross section.

3. A belt reeling mechanism as claimed in claim 1 or 2, wherein the attenuating element is annular and encircles the disc in the region of contact with the tip of the lever, the arrangement and diameter of the ring being such that the lever tip engaging surfaces of the abutments in the form of teeth project beyond the periphery of the ring.

4. A belt reeling mechanism as claimed in claim 3, wherein the attenuating element is mounted in a circumferential groove in the toothed disc, this circumferential groove being located adjacent to the row of teeth.

5. A belt reeling mechanism as claimed in claim 3, wherein the attenuating element is mounted between two rows of teeth on the disc.

6. A belt reeling mechanism as claimed in claim 1 or 2, including a sensor housing which accommodates the ball or pendulum and which is provided with a mounting which enables the periphery of the attenuating element to extend, in the pivot region of the lever in such a way that, when cieflected, the lever engages with its tip in the path of flanks of the abutments of the disc, but is not able to contact the base of the abutments.

7. A belt reeling mechanism as claimed in claims 1,2 or 6, wherein below the pivot region of the lever, the mounting is in the form of an attachment with an undercut on which the attenuating element rests, the periphery of the ring limiting the pivot range of the lever.

8. A belt reeling mechanism as claimed in claim 7, wherein the attachment is provided on the side of the sensor housing which faces the disc and the attenuating element is mounted in such a way that its central plane extends substantially at a tangent to the pivot radius of the lever in the locking position thereon.

9. A belt reeling mechanism as claimed in any of the preceding claims, wherein the annular attenuating element consists of an elastomer, preferabiy rubber, and its mounting is sealed off in light-proof manner.

10. A belt reeling mechanism as claimed in claim 1, wherein the attenuating element consists of solidified flexible material, e.g. plastics material, which has been applied in liquid or paste form.

11. Belt reeling mechanisms substantially as hereinbefore described with reference to the accompanying drawings.