GB2032252A - Adjusting position of inertia weight in seat belt reels - Google Patents

Abstract

A device for use with reel mechanisms for vehicle safety belts. The device serves to activate the locking mechanisms of a vehicle inertia safety belt and comprises an inertia body (18) located in a support (17) and an operating member (20) which is arranged to cooperate with the inertia body (18) and with a mechanism for locking the reel shaft (2) of the safety belt (1). The support (17), the inertia body (18) and the operating member (20) constitute a unit which is rotatable about a horizontal central axis of the support (17) and which is displaceable along an arc having a radius of curvature with the axis of the reel shaft (2) as its centre. Thus the unit can be adjusted relative to the reel depending upon the orientation of the reel as it is fitted in a vehicle. <IMAGE>

Description

SPECIFICATION Device for use with reel mechanisms for vehicle safety belts This invention relates to a device for activating a locking mechanism for a vehicle inertia safety belt, the device comprising an inertia body, located in a support and an operating member arranged to cooperate with the inertia body and with a mechanism for locking the reel shaft of a vehicle safety belt, in which the locking mechanism comprises of a ratchet wheel rotatable with the reel shaft and a pawl co-operable with the teeth of the ratchet wheel, which pawl is arranged in such a way that a displacement of the inertia body out of a neutral position is effective to cause the operating member directly or indirectly to move the pawl into engagementwith a ratchet tooth.

A reel mechanism in a vehicle must be designed in such a manner that it is locked against unwinding of the safety belt as soon as the vehicle is subjected to abnormal changes in its movement. This for exam ple takes place in connection with an abnormally rapid deceleration of the vehicle such as can occur when it is involved in a collision with another vehicle. Also when the vehicle occupyies an oblique position exceeding a certain maximum angle, which can occur, by way of example, when the vehicle lands up in a ditch, the locking mechanism comes into operation. The locking mechanism in such means usually is actuated by an inertia, body which can move in at least one lateral direction.

The present invention aims to provide a device for activating a locking mechanism of the kind above referred to with good functional characteristics and which, relative to varying positions of mounting of the reel belt, is easy to adjust.

According to the invention, there is provided a device for activating a locking mechanism for a vehicle inertia safety belt, said device comprising an inertia body located in a support and an operating member arranged to cooperate with the inertia body and with a mechanism for locking the reel shaft of a vehicle inertia safety belt, in which the locking mechanism comprises a ratchet wheel rotatable with said reel shaft and a pawl arranged to engage with a tooth of the ratchet which in response to movement of the operating member when the inertia body is displaced from a normal stable position wherein the support, the inertia body and the operating member constitute a unit which is rotatable about a horizontal central axis of the support and which is displaceable along an arc having a radius of curvature with the axis of the reel shaft as its centre.

The invention will now be further described, by way of example with reference to the drawings, in which Figure 1 is a side elevation view of a reel mechanism of a vehicle safety belt for automobiles with some parts shown broken away to reveal further parts.

Figure 2 is a view of the reel mechanism illustrated in figure 1 as seen from a point located underneath the same and showing the reel mechanism again with some parts shown broken away and with the activating device omitted.

Figure 3 is an exploded perspective view of the activating device; Figure 4 is a vertical longitudinal cross-section through the activating device occupying an angular position deviating from the neutral position; Figure 5-7 illustrate the activating device as seen from the front in different positions of adjustment; and Figure 8 is a side elevational view of the reel mechanism after rotating a quater of a turn in relation to the position shown in figure 1.

Referring to the drawings, a vehicle safety belt 1 is wound up on a reel shaft 2. A wheel 4 provided with sawtooth like ratchet teeth 3 is rigidly mounted on this shaft 2. A locking pawl 6, radially mounted outside of the ratchet wheel 4 in a housing 5 such a manner that it can move freely, co-operates with the ratchet teeth 3.

A camshaft pulley 7 is arranged to close to the ratchet wheel 4, said pulley having the same centre of rotation as the wheel 4. The camshaft pulley 7 is provided with cams 8 around its periphery and between said cams there are arc-shaped recesses 9.

The cams 8 are equal in number to the number of teeth 3 of the ratchet wheel 4 and in the normal position of the cammed pulley 7 each one of said cams 8 is located right in front of a tooth.

The pulley 7 can be rotated in relation to the ratchet wheel 4 against the bias of a spring means 11 located in an arc-shaped opening in the form of a slot 10 in the camshaft pulley. This spring means is stretched between one end of the slot 10 and a pin 12 rigidly connected with the ratchet wheel 4 and extending through the slot.

In a relative rotation movement between the pulley 7 and the ratchet wheel 4, the ratchet teeth 3 will appear in the recesses 9. This movement is limited to an angle, which corresponds to at the most one half of the distance between two juxtapositioned cams 8 or ratchet teeth 3 by means of a second arc-shaped slot 13 provided in the pulley 7 in which a stop pin 14 rigidly connected with the ratchet wheel 4 is located.

A carrier member 15 is composed of a wire spring provided with two legs, one leg of which supports a cross arm 16 (see figure 2) which with a certain spring tension abuts against the pulley 7 and during normal unwinding or winding up of the safety belt for automobiles 1 slides along the cams 8 and the recesses 9 and is guided by the cams above and past the ratchet teeth 3. The other leg of the carrier member 15 is attached inside the housingS.

The activating device, which is intended to bring the reel mechanism to a stop, if the vehicle is subjected to an unnormal change in its movement or if the vehicle lands up in an unnormal oblique position, comprises a spherical inertia body 18 located in a cup-shaped support 17, the outside of which has a cylindrical shape. The inertia body suitably comprises a metal ball. By providing the bottom of the support 17 with a centrally positioned hole for a marked recess, the spherical body 18 cannot displace itself out of the neutral position with only insignificant angular changes.

An operat;ng member is provided around the upper portion of the spherical body 18, which member in the illustrated embodiment comprises a ring 20 which is provided with a protruding nose 21.

The operating member also has a flat portion 22, which is pivotally mounted on the lower edge of the support 17. When the spherical body 18 by occuping an oblique position in a random direction by means ofthe reel mechanism leaves its normal neutral or stable position, it urges the operating member 20 to pivot out for a certain distance from the support 17.

An example of such a situation is illustrated in figure 4.

A toothed disc 23 is further provided on the outside of the pulley 7, said disc by friction contact rotating together with the pulley in connection with an unwinding or winding up of the safety belt 1. The toothed disc 23 is provided with teeth 24 around its periphery with which the nose 21 of the operating member 20 is arranged to co-operate in order to brake the pulley 7.

This arrangement thus constitutes, in effect, a pendulum which functions in such a manner that when the reel mechanism for instance due to an abrupt change of velocity or the occupation of an oblique position, brings the spherical body 18 out of its neutral position, this ball forces out the operating member 20, so that its nose 21 engages one of the teeth 24 (see figure 4). The toothed disc 23, which in this way has been stopped, by its friction contact with the camshaft pulley 7 brakes this pulley, so that it is rotated relative to the ratchet wheel 4. A tooth 3 of the ratchet wheel 4 will thereby engage the cross arm 16 of the carrier member 15 and thus cause the carrier member to move the pawl 6 into engagement with a tooth 3 of the ratchet wheel 4 whereafter the pawl consequently will take up the load and stop the reel mechanism.

According to the invention, the cup-shaped sup port 17, the spherical body 18 and the operating member 20 constitute a single unit which for one thing, can be rotated round the horizontal central axis of the support 17 and, for another thing, can be displaced along an arc having the same centre as the reel shaft 2. Said unit is located in a housing 25, and this housing is arranged on a plate 26 and can be displaced together with this plate round the toothed disc 23. In this manner the reel mechanism can be mounted for vertical adjustment in other positions than the one shown in figure 1, by way of example in the position illustrated in figure 8. A measuring scale 27 placed outside of the plate 26 makes it possible to adjust the housing 25 with the activating device in an exactly desired angular position.

In order to make it possible to mount the reel mechanism in different angular positions deviating from vertical plane, the unit comprising the support 17, the spherical inertia body 18, and the operating member 20 is rotatable in the housing 25 round the horizontal centred axis of the support. In this connec tion, the support 17 is suitably provided with one or more recesses or grooves in its outside end wall 28.

In the embodiment shown in the drawings a single groove 29 is provided extending transversely across the wall. The housing 25 around the support 17 is moreover provided with tongues SO which can be folded inwards into the groove 29 in order to hold the support in a certain desired adjusted angular position.

Figures 6 and 7 schematically show how the reel mechanism has been inclined somewhat in different directions from the vertical position shown in figure 5, whereafterthe support 17 has again been rotated into a neutral position and been fixed in this position by inwards folding of two tongues 30 into the groove 29.

By means of the different adjustment positions of the pendulum means, the reel mechanism can easily be adapted to different types of vehicles and in any occuring case it can therefore be mounted in such a position that unwinding and winding up of the safety belt 1 can always take place in the most convenient direction.

The invention is not limited to the embodiment described and illustrated, but can be varied in a number of ways within the scope of the claims. By way of example, the support 17 for said stepwise adjustment can be provided with longitudinal grooves and the housing 25 with a bar engaging anyone of said grooves or vice versa. In connection with such an embodiment one must consequently extract the support 17 from the housing 25, rotate it into a new desired angular position and thereafter again push it into the housing with the bar engaging a new groove.

Claims (8)

1. A device for activating a locking mechanism for a vehicle inertia safety belt, said device comprising an inertia body located in a support and an operating member arranged to co-operate with the inertia body and with a mechanism for locking the reel shaft of a vehicle inertia safety belt, in which the locking mechanism comprises a ratchet wheel rotable with said reel shaft and a pawl arranged to engage with a tooth of the ratchet which in response to movement of the operating member when the inertia body is displaced from a normal stable position, wherein the support, the inertia body and the operating member constitute a unit which is rotable about the horizontal central axis of the support and which is displaceable along an arc having a radius of curvature with the axis of the reel shaft as its centre.

2. An activating device according to claim 1, wherein said unit is stepwise rotable round said horizontal axis of the support.

3. An activating device according to claim 1 or claim 2, wherein the support, the inertia body and the operating member are located inside a housing which is displaceable along said arc.

4. An activating device according to claim 3, wherein the housing is adjustable according to a scale which indicates the adjusted angular position of the housing.

5. An activating device according to claim 3 or claim 4, wherein the support is provided with one or more recesses or grooves and the housing is provided with tongues which can be folded inwards into said recesses or grooves in order to hold the support in position.

6. An activating device according to any preceding claim, wherein the support is provided with a cup-shaped recess the inertia body comprises a spherical element adapted to be received in the recess in the support, and the operating member comprises an annular arm enclosing the upper portion of the spherical element, which arm is provided with a protruding portion engageable with a toothed wheel or disc and is pivotally mounted in the support.

7. An activating device according to claim 6, wherein the toothed wheel as disc is mounted for rotation with a cammed pulley by means of a function contact between the wheel or disc and the pulley and wherein, when a tooth of the toothed wheel or disc is engaged by the arm of the operating member, the wheel or disc is effective to brake the pulley and to cause a cam on the surface of the said pulley to actuvate the pawl to move the same into engagement with a tooth of the ratchet wheel.

8. A device for activating a locking mechanism for a vehicle inertia safety belt, said device being substantially as described herein with reference to the drawings.