GB2210254A

GB2210254A - Tightening device for a safety belt reeling device

Info

Publication number: GB2210254A
Application number: GB8822965A
Authority: GB
Inventors: Thomas Schmidt; Klaus Butenop
Original assignee: Autoflug GmbH
Current assignee: Autoflug GmbH
Priority date: 1987-09-30
Filing date: 1988-09-30
Publication date: 1989-06-07
Anticipated expiration: 2008-09-30
Also published as: IT1227253B; GB8822965D0; GB2210254B; SE8803421D0; SE8803421L; IT8822140A0; ES2008614A6; DE3732878A1; FR2620988A1

Description

a V 1 - Tightening device for a safety belt reeling device The invention

relates to a tightening device for a safety belt reeling device.

A tightening device is known from German 34 07 378 having a cable drive which is actuatable in the event of a crash, the cable pulley of which can be coupled in form-locking manner to the winding shaft of the belt reeling device via a locking member which is eccentrically mounted in spring loaded manner on the cable pulley and can be swung out radially to engage circumferential teeth coupled to the belt winding shaft. The mounting and mass relationships at the locking member are such that, in the event of actuation. the locking member will lag behind the rotary movement of the cable pulley because of its inherent inertia and will be pivoted radially outwards because of its eccentric mounting.

The disadvantage of this design of a coupling between the belt tightening means and belt reeling means is that the response threshold of the locking member is difficult to determine since the cable pulley initially has to undergo certain rotational acceleration before the response threshold of the locking member is reached, causing it to pivot outwards; consequently. part of the limited drive travel for the cable pulley cannot be converted into winding movement of the belt winding shaft.

The aim of the invention is therefore to improve on the tightening device of the known type so that the engagement of the coupling locking member is 9210254 bi 1 1 i initiated in positive manner independently of the rotational acceleration of the cable pulley.

According to the invention there is provided a tightening device for a safety belt reeling device, said tightening device including a housing, a cable pulley to be driven by a cable drive actuatable in the event of a crash, a locking member mounted on said pulley for movement between an initial rest position and a locking position and spring biased towards said locking position in which, in use, said locking member serves to lock said pulley for rotation with said belt reeling device, movement of said locking member relative to said pulley being controlled by a pin and slot arrangement, and securing means for holding said locking member in said initial position against said spring bias, said securing means being releasable as a result of relative movement between said pulley and said housing consequent upon actuation of said cable drive.

Thus the locking member which is spring loaded into the locking position is held in its unlocked initial position by securing means which permit movement of the locking member in the event of actuation of the cable drive and consequent relative movement between the cable pulley and the housing at the very start of the drive motion for the cable pulley, so that the pin-slot control arrangement between the cable pulley and the locking member resuls in positive, controlled movement of the locking member until it brings about locking of the pulley for rotation with the belt reeling device.

This has the advantage that an accurately adjusted rotational travel between the cable pulley and -C 1 the housing is sufficient on its own to bring about movement of the locking member without having to overcome particular forces such as the inertia of the cable pulley or the breaking strength of a frangible securing point. As a result, a coupling between the cable pulley and the belt winding shaft can be substantially more precise in its acutuation characteristics and with less waste of the drive movement than is the case with force-dependent response mechanisms for the locking member.

According to one embodiment by way of example of the invention, the locking member which is spring loaded into the locking position is to be secured in the rest position by means of a spring arm of a spring ring integral with the housing, said spring arm extending into the control path of the pinslot control arrangement, whereby in the event of actuation relative movement between the cable pulley and the housing through a predetermined angle causes the spring arm to slide out of the control slot, so that the pin-slot control can become effective with respect to radial pivoting of the locking member as a result of the spring loading provided.

According to another embodiment by way of example of the invention, the control pin which guides the movement of the locking member is mounted on a separate coupling ring fixed to the housing as the securing means, in such a way that relative movement between the housing and the cable pulley at the start of the drive action causes the outward movement of the locking member via the pivoting of the coupling ring, whilst the rest position of the locking member in the unlocked position is secured by means of a ratchet connection of the coupling ring to the housing.

Two preferred embodiments of the invention will be described hereinafter by way of example only and with reference to the accompanying drawings in which; rig. 1 shows a diagrammatic representation of the coupling side of a tightening device in the unlocked position of the locking member, Fig. 2 shows the article of Figure 1 in section along the line II-II of Figure l, Fig. 3 shows the article of Figure 1 with the coupling locked, Fig. 4 shows the article of Figure 3 in sectional view on the line IV-1V of Figure 3, Fig. 5 shows another embodiment of the coupling end viewed as in Figure 1, Fig. 6 shows the article of Figure 5 in section on the line VI-VI of Figure 5.

on a spindle extension 10 of a belt winding spindle of a belt reeling device (not shown in detail) cable pulley 11 is rotatably mounted, having drive cable 12 wound on it. The free end of this drive cable is connected to an energy store (not shown either) which, in the event of actuation, causes a pulling movement of the drive cable in the direction of the arrow 13.

on the side of the cable pulley 11 facing the belt reeling device, a locking member 14 having external t Z t- r, 1, 1 I.

teeth 15 is eccentrically mounted thereon, whilst in the plane of the locking member 14, at the belt reeling end, a thrust ring 16 fixedly connected to the belt winding spindle 10 and having inner teeth 17 associated with the teeth 15 of the locking member is mounted in such a way that the radially pivotable locking member 14 in its locked position engages with its teeth 15 with the teeth 17. The locking member 14 engages with a control pin 18 in a radially extending control slot 19 on the cable pulley 11 so that the locking member 14 can be guided radially outwards relative to the cable pulley 11 via the pin-slot control 18, 19 thus formed. The radially outwardly directed end position of the control pin 18 in the slot 19 corresponds to the rest position of the locking member in which the locking member 14 does not engage with the thrust ring 16 of the belt winding shaft 10, whereas in the opposite inner end position of the control pin 18 in the control slot 19 the teeth 15, 17 of the locking member 14 and thrust ring 16 engage with each other. A leaf spring 20 acts on the periphery of the locking member 14 and biases the latter into the locking position (Fig. 3).

A spring ring 22 passing through the cable pulley 11 is secured to a housing 21 containing the cable pulley, one spring arm 23 of said spring ring 22 extending into the control slot 19 of the cable pulley 11 and securing the control pin 18 in the radially outwardly directed end position in the rest position of the locking member (Figs. 1 and 2); in this position, the locking member 14 is secured in its rest position without engagement of the teeth provided that the cable pulley does not alter its position.

If, in the event of a crash, the triggering of the energy store causes rotation of the cable pulley 11 relative to the housing 21 in the direction of the arrow 13, the cable pulley 11 moves relative to the housing 21 and consequently relative to the spring ring 22, as a result of which the spring arm 23 is moved out of the control slot 19 and thus opens the way for the movement of the control pin 18 into the inwardly directed end position in the control slot 19 (Figs. 3 and 4) in which the teeth engage and hence provide a form-locking coupling between the cable pulley 11 and belt winding shaft 10. As a result of the small rotational movement provided, the coupling engagement of the teeth takes place very rapidly.

In the embodiment shown by way of example in Figs. 5 and 6, the control pin 18 engaging in the control slot 19 of the cable pulley 11 and guiding the locking member 14 in an associated fork-recess 24 is Dart of an annular component 25, preferably made of plastics, which is arranged in the plane of the cable pulley 11 so as to rotate therewith about the shaft 10. on its side radially opposite the control pin 18, the ring 25 has a resilient arm 26 of which an offset nose 27 abuts on the inside of the housing wall 21. On the arc swept by the arm 26 during the rotational movement of the coupling ring 25, elevated portions 28 are formed on the housing wall 21, between which the nose 27 of the arm 26 can be located on the one hand, whilst on the other hand the arm 26 with its nose 27 can travel over said elevated portions 28 in a manner of a ratchet connection in the event of actuation. To this extent, this ratchet connection 27, 28 between the coupling ring 25 and the housing 21 constitutes means for securing the locking member in its rest position.

7 In the rest position which is shown in Pigs. 5 and 6, the locking member 14 is held in its unlocked position on the cable pulley 11 by the control pin 18 of the coupling ring 25 which is in turn located on the housing 21 via the arm 26 and the nose 27. if relative movement occurs between the cable pulley 11 and housing 21 in the event of actuation, as described, the end of the control slot 19 of the cable pulley 11 rotates as far as the stop on the control pin 18 and takes the latter with it during further rotational movement of the cable pulley 11, as a result of which the eccentrically mounted locking member is subjected to controlled deflection until its teeth 15 engage with the internal teeth 17 of the thrust ring 16; the ratchet connection 27, 28.does not present any great resistance to this control movement, with the result that the coupling ring 25 together with the control pin 18 rotates with the rotary movement of the cable pulley 11 until the tightening movement has ended.

The features disclosed in the foregoing specification, claims and drawings both individually and in any desired combination may be regarded as essential to the present invention.

1

Claims

1. Tightening device for a safety belt reeling device, said tightening device including a housing, a cable pulley to be driven by a cable drive actuatable in the event of a crash, a locking member mounted on said pulley for movement between an initial rest position and a locking position and spring biased towards said locking position in which, in use, said locking member serves to lock said pulley for rotation with said belt reeling device, movement of said locking member relative to said pulley being controlled by a pin and slot arrangement, and securing means for holding said locking member in said initial position against said spring bias, said securing means being releasable as a result of relative movement between said pulley and said housing consequent upon actuation of said cable drive.

2. Tightening device according to claim 1 wherein on the housing there is provided a spring ring which, in the initial rest position of the locking member, by means of an arm-like portion engages in a control slot of said pin and slot arrangement, said slot being provided in the cable pulley and secures a control pin of said pin and slot arrangement, -which pin extends into said slot and is provided on the locking member, in the position in said slot corresponding to the rest position of the locking member.

3. Tightening device according to claim 1 including coupling ring rotatable with the cable pulley, control pin of said pin and slot arrangment being X i z - 9 provided on said coupling ring, said pin engaging in a control slot of said pin and slot arrangement formed in said cable pulley, said pin engaging in a recess in the locking member, the coupling ring being located in the rest position of the locking member by means of a radially projecting arm thereof engaging with elevated portions of said housing.

4. Tightening device according to claim 3, wherein the arm is disposed on the coupling ring radially opposite the pin and slot arrangement.

5. Tightening device according to claim 3 or 4 wherein on the housing surface, on the arc swept by the arm as it rotates with the cable pulley, there is provided a series of elevated portions the height of which is such that in the event of actuation the arm can resiliently move over them with a ratchet action.

6. Tightening device substantially as described with reference to Figs. 1 to 4 of the accompanying drawings.

7. Tightening device substantially as described with reference to Figs 5 and 6 of the accompanying drawings.

8. Safety belt reeling device incorporating a tightening device as claimed in any preceding claim.

I ', Ainl,iqho.!! IPAP at Tle Pat-ri Wice. Stat, House 6671 HiCh Yc)t:rr.. London WC1R 4Tr- Pjz-her ccpies mk,, be ob=ed frcn The Patent Office.