GB2276307A

GB2276307A - "Webbing clamp of a safety-belt arrangement"

Info

Publication number: GB2276307A
Application number: GB9305887A
Authority: GB
Inventors: Tony Jonsson
Original assignee: Autoliv Klippan SNC
Current assignee: Autoliv Klippan SNC
Priority date: 1993-03-22
Filing date: 1993-03-22
Publication date: 1994-09-28
Anticipated expiration: 2013-03-22
Also published as: GB2276307B; GB9305887D0

Abstract

A lever 6 forming part of webbing clamp comprises an intermediate portion located between means 30, 31 to engage a pivot shaft 5 and means defining or engaging a clamping shoe 8. As shown the intermediate portion comprises a plurality of webs. The webs are formed in two groups (36, 37, 38; 39, 40, 41, Figs. 3 and 4) which groups diverge from one another from the ends thereof adjacent the clamping shoe. Extensions 18, 19 of the level cooperate with stops 20 to 23 formed on the frame 1 to limit the movement of the lever. <IMAGE>

Description

DESCRIPTION OF INVENTION "IMPROVEMENTS IN OR RELATING TO A SAFETY-BELT ARRANGEMENT" THE PRESENT INVENTION relates to a safety-belt arrangement and more particularly relates to a web clamp.

A conventional safety-belt, for use in a motor vehicle, is wound on a spool in a retractor mechanism. The spool of the retractor mechanism is adapted to lock in response to rapid deceleration of the vehicle, such as is experienced in an accident situation. The spool may also be adapted to lock if the belt is withdrawn from the retractor mechanism at a speed greater than a predetermined speed. However, when the spool has locked, a further length of safety-belt may be withdrawn from the retractor mechanism due to the so-called "film spool effect". This is undesirable since a safety-belt is intended to retain the person wearing the safety-belt in position and not permit the person to move forwards. In contrast, as webbing is paid out due to the "film spool effect" the person utilising the seat-belt is able to move forwards.

It has thus been proposed to utilise a web clamp in conjunction with a retractor mechanism, the web clamp incorporating a clamping arrangement adapted to clamp the webbing to prevent movement of the webbing.

A web clamp has been proposed which utilises a clamping shoe adapted to engage the webbing and clamp the webbing against a fixed element, the clamping shoe being mounted at one end of a pivoted lever. The other end of the pivoted lever is mounted on a pivot shaft, which extends between two spaced apart plates.

When the clamping shoe has engaged the webbing, the force applied to the webbing will tend to cause the lever to move in a pivotal manner, thus increasing the clamping force. However, a force equal and opposite to the clamping force is applied to the pivot shaft.

A typical lever that has been proposed before comprises a portion defining a through-bore adapted to receive the pivot shaft. Extending from this portion is a principal web of substantially planar form. The plane of the web substantially intersects the axis of the pivot shaft, and extends substantially radially of the pivot shaft. The principal web is reinforced by transverse reinforcing webs projecting on either side of the main web.

The reinforcing webs each lie in a plane which is perpendicular to the axis of the pivot shaft, the reinforcing webs thus extending parallel with each other.

The present invention seeks to provide an improved safety-belt arrangement.

According to this invention there is provided a safety-belt arrangement comprising a clamp adapted to clamp a webbing strap forming part of a safety-belt, the clamp comprising a frame defining journals carrying a pivot shaft, there being a lever mounted on or formed integrally with the pivot shaft and carrying or being formed with a clamping shoe, the lever being movable pivotally from a release position in which the shoe does not engage the webbing strap to a clamping position in which the shoe engages the webbing strap, clamping the webbing strap between the shoe and a fixed element, the lever having portions engaging the pivot shaft at points immediately adjacent the journals supporting the pivot shaft, a safetybelt arrangement comprising a clamp adapted to clamp a webbing strap forming part of a safety-belt, the clamp comprising a frame defining journals carrying a pivot shaft, there being a lever mounted on the pivot shaft and carrying or being formed with a clamping shoe, the lever being movable pivotally from a release position in which the shoe does not engage the webbing strap to a clamping position in which the shoe engages the webbing strap, clamping the webbing strap between the shoe and a cooperating element, the lever comprising means defining or adapted to engage a clamping shoe, spaced apart means adapted to engage the pivot shaft and an intermediate portion extending between the means to engage the clamping shoe and the means to engage the pivot shaft, the intermediate portion comprising a plurality of webs, the webs comprising two groups of webs, each group comprising a plurality of webs, the two groups of webs diverging from the ends thereof adjacent the means defining or adapted to engage the clamping shoe.

The lever may be made strong enough to withstand the forces exerted on it in an economic manner.

Conveniently the longitudinal axes of the webs forming the two groups of webs make an acute angle with an axis perpendicular to the axis of the pivot shaft.

Preferably the lever has portions which engage the pivot shaft at points immediately adjacent the journals supporting the pivot shaft, thus minimising any tendency for the pivot shaft to deform.

Conveniently stop means are provided mounted on the frame adapted to engage co-operating means mounted on the lever when the lever is in the clamping position.

The stop means serve to prevent the lever moving beyond the desired clamping position thus limiting the maximum force that can be applied to the pivot shaft.

Preferably resilient means are provided to bias the lever to the release position and further stop means are provided adapted to be engaged by said co-operating means when the lever has been moved to the release position.

Preferably the webs, at their ends adjacent the means defining or adapted to engage the clamping shoe are substantially uniformly spaced apart. Thus the force applied by the lever to the clamping shoe can be applied substantially uniformly across the width of the clamping shoe.

Advantageously the webs form, at their ends adjacent the means defining or adapted to engage the clamping shoe, a substantially uniform corrugated pattern.

Conveniently the corrugated pattern is such that individual webs define planes which extend in directions which make an acute angle with an axis parallel with the axis of the pivot shaft, these webs being inter-connected by transverse webs which extend substantially parallel with the said axis parallel with the axis of the pivot shaft.

Advantageously at least some of the transverse webs are provided with reinforcing buttresses.

Conveniently the transverse web extending between the two groups of webs is of substantially triangular form.

The invention also provides a lever for use in a safety-belt arrangement as described above, said lever comprising means defining or adapted to engage a clamping shoe, spaced apart means adapted to engage the pivot shaft and an intermediate portion extending between the means to engage the clamping shoe and the means to engage the pivot shaft, the intermediate portion comprising a plurality of webs, the webs comprising two groups of webs, the two groups of webs diverging from the ends thereof adjacent the means defining or adapted to engage the clamping shoe.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which: FIGURE 1 is an end elevational view of a web clamp for use with a safety-belt taken on the line A-A of Figure 2, FIGURE 2 is a part-sectional view of the web clamp of Figure 1 taken on the line B-B of Figure 1, FIGURE 3 is a part elevational and part-sectional view of the lever of the web clamp of Figure 1 taken on the line C-C of Figure 4, and FIGURE 4 is a sectional view of the lever of Figure 3 taken on the line D-D of Figure 3.

Referring initially to Figures 1 and 2 of the accompanying drawings, a web clamp comprises a frame 1 which has a base 2 and two upstanding arms 3,4 which are spaced apart. The arms define aligned apertures which receive the ends of a pivot shaft 5 and which constitute journals for the pivot shaft 5. The pivot shaft 5 thus extends between the arms 3 and 4 parallel with the base 2 of the frame 1. A lever 6 is pivotally mounted on the pivot shaft 5 and defines, at its lower end, a downwardly open arcuate recess 7. Mounted within the recess is a clamping shoe 8 which has an upper arcuate region 9 adapted to be snugly received within the arcuate recess 7 and which has a lower planar face 10 provided with a plurality of protruding teeth 11. The protruding teeth are located immediately above a webbing strap 12 which comprises a safety-belt to be clamped, that webbing strap 12 running immediately above the base 2 of the frame 1, which is fixed in position. It is to be appreciated that the lever 6 may move between a release position as illustrated in Figure 2 and a clamping position in which the teeth 11 firmly engage the webbing strap 12, the clamping shoe 8 firmly claps the webbing strap against the base of the frame. In an alternative embodiment the clamping shoe may be formed integrally with the lever.

As can be seen from Figure 2, a spring 13 is provided which engages a projection 14 formed at the lower end of the lever 6, biassing the lever in the direction of the arrow 15, that is to say biassing the lever towards the release position. An activator 16 is provided connected to an appropriate sensor, adapted to move in the direction of the arrow 17 to push the lever 6 against the bias from the spring 13 to the clamping position.

As can be seen in Figures 1 and 2 the lever 6 carries, at its lower end, two projections 18,19 which extend to either side of the webbing, at a position just above the webbing. Thus the projections 18,19 effectively extend parallel with the axis of the pivot shaft 5, and thus extend to positions very close to the arms 3 and 4 of the frame 1. Each projection 18,19 is located between two stops 20,21,22,23 which project inwardly form the arms 3 and 4 of the frame and which thus serve to limit the movement of the lever. The stops 21 and 23 are intended to limit movement of the lever towards the release position, under the biassing effect of the spring 13, and the stops 20,22 are engaged by the projections 18 and 19 when the lever has moved to the clamping position. The stops 20 and 22 thus prevent the lever, when it has reached the clamping position, from moving further even if significant force is applied to the webbing strap 12, thus limiting the total clamping force that can be applied and consequently limiting the total reactive force that can be transmitted by the lever 6 to the pivot shaft 5.

As can be seen more clearly from Figures 3 and 4 the pivot lever 6 comprises, at its upper end, two upwardly extending portions 30,31 which define co-aligned bores 32,33 which together receive the pivot shaft 5. The outer edges of the portions 30,31 are spaced apart by a distance greater than the width of the clamping shoe and thus, as can be seen most clearly in Figure 1, the portions 30 and 31 are located immediately adjacent the journals defined by the arms 3 and 4 of the frame 1 which support the pivot shaft 5. It is thus to be appreciated that any force applied by the lever 6 to the pivot shaft 5 is applied to the shaft 5 at points immediately adjacent the journals supporting the shaft 5, thus serving to minimise any deformation of the shaft 5 and, in any event, minimising any upward movement of the lever as a consequence of the force applied to the shaft 5.

The intermediate region of the shaft 6, extending between the portions 30 and 31 which engage the shaft 5, and the lower part which defines the arcuate recess 7 is of a very different configuration to the configuration of the lever of the prior art arrangement described above.

Instead of having a principal planar web extending substantially radially and coincident with the axis of the pivot shaft, with reinforcing webs which lie in a plane extending perpendicularly to the axis of the pivot shaft, the intermediate portion of the lever 6 is substantially symmetrical about a central line 34, indicated in Figure 3, and comprises two groups of webs. The webs define, at their lower ends, a substantially regular corrugated pattern where the webs engage an element 35, the underside of which defines the arcuate recess 7. This regular corrugated pattern extends across the entire width of the element 35 which supports the clamping shoe 8. Thus, if reference is made to Figure 4, it can be seen that webs 36,37 and 38 form a substantially uniform corrugated pattern in the region of the element 35. It is to be appreciated that the additional webs 39,40 and 41 also, at their lower ends, continue the substantially regular and uniform corrugated pattern. Thus the lower ends of all of the webs are substantially uniformly spaced apart, enabling force to be applied uniformly to the clamping shoe 8. It is to be noted that the webs 36,37,38,39,40 and 41 at their lower ends, each extend in and thus define a plane which is inclined at an acute angle to the axis of the arcuate recess 7 which is, of course, parallel with the axis of the pivot shaft 5.

At each side of the lever, a further web is provided, comprising the webs 42,43 which extend substantially perpendicularly to the axis of the recess 7.

It is to be noted that the adjacent webs are interconnected by transverse webs which extend substantially parallel with the axis of the recess 7. Thus the web 42 and the web 36 are inter-connected by a transverse web 44.

The web 36 and the web 37 are inter-connected by a transverse web 45 which is provided with a substantially triangular reinforcing buttress 46 which extends perpendicularly to the axis of the recess 7. The webs 37 and 38 are inter-connected by a transverse web 47 and the webs 38 and 39 are inter-connected by a transverse web 48 which again has a triangular reinforcing buttress 49. The webs 39 and 40 are inter-connected by a web 50, and the webs 40 and 41 are inter-connected by a web 51 which has a triangular reinforcing buttress 52. Finally, the web 41 and the web 43 are inter-connected by a transverse web 53.

Although the lower parts of the webs as described above form a uniform corrugated pattern, as can be seen at the right-hand side of Figure 4 and as described above, in the region where the webs are connected to the element 35, it is to be noted that the two groups of webs mentioned above diverge outwardly towards the upwardly extending portions 30,31. Thus the webs form two diverging groups of webs as can be seen most clearly in Figures 1, 3 and 4.

The longitudinal axes of the webs forming the groups of webs make an acute angle with an axis perpendicular to the axis of the pivot shaft 5.

Thus, if reference is made to Figure 3 the transverse webs 53 and 50 of one of the groups of webs can be clearly seen, these webs extending to a point adjacent the upwardly extending projection 30. The webs 42,36,37 and 38 can be clearly seen towards the right-hand side of Figure 3, being inclined towards the upwardly extending projection 31.

It is to be appreciated that the transverse web 48, which, can be seen from Figure 3, spans the line of symmetry 34, has a very small dimension at its lower end, adjacent the triangular reinforcing buttress 49 and a much larger dimension at its upper end, as illustrated at 54 in Figure 4. The web 48, when viewed in elevation is thus of triangular form as can be seen in Figure 3.

It is thus to be appreciated that the various webs extending between the part of the lever engaging the pivot shaft 5 and the part of the lever carrying the clamping shoe 8 comprises a plurality of webs, the webs forming two groups of webs, the webs in each group defining, at their ends adjacent the clamping shoe, a substantially uniform corrugated pattern, the two groups of ends diverging outwardly away from each other towards the parts of the lever that engage the pivot shaft.

The design of the lever described above enables the lever to be fabricated at a relatively low cost, but whilst still providing a lever which has significant strength.

The provision of the stops 20 and 22 prevent an excessive force being applied to the lever, whilst still enabling the clamp to operate in a satisfactory manner.

In an alternative embodiment the lever 6 may be formed integrally with the pivot shaft 5.

Claims

CLAIMS:

1. A safety-belt arrangement comprising a clamp adapted to clamp a webbing strap forming part of a safetybelt, the clamp comprising a frame defining journals carrying a pivot shaft, there being a lever mounted on or formed integrally with the pivot shaft and carrying or being formed with a clamping shoe, the lever being movable pivotally from a release position in which the shoe does not engage the webbing strap to a clamping position in which the shoe engages the webbing strap, clamping the webbing strap between the shoe and a co-operating element, the lever comprising means defining or adapted to engage a clamping shoe, spaced apart means adapted to engage the pivot shaft and an intermediate portion extending between the means to engage the clamping shoe and the means to engage the pivot shaft, the intermediate portion comprising a plurality of webs, the webs comprising two groups of webs, each group comprising a plurality of webs, the two groups of webs diverging from the ends thereof adjacent the means defining or adapted to engage the clamping shoe.

2. An arrangement according to Claim 1 wherein the longitudinal axes of the webs forming the two groups of webs make an acute angle with an axis perpendicular to the axis of the pivot shaft.

3. An arrangement according to Claim 1 or 2 wherein the lever has portions which engage the pivot shaft at points immediately adjacent the journals supporting the pivot shaft.

4. An arrangement according to any one of the preceding Claims wherein stop means are provided mounted on the frame adapted to engage co-operating means mounted on the lever when the lever is in the clamping position.

5. An arrangement according to Claim 4 wherein resilient means are provided to bias the lever to the release position and further stop means are provided adapted to be engaged by said co-operating means when the lever has been moved to the release position.

6. An arrangement according to any one of the preceding Claims wherein the webs, at their ends adjacent the means defining or adapted to engage the clamping shoe, are substantially uniformly spaced apart.

7. An arrangement according to any one of the preceding Claims wherein the webs form, at their ends adjacent the means defining or adapted to engage the clamping shoe, a substantially uniform corrugated pattern.

8. An arrangement according to Claim 7 wherein the corrugated pattern is such that individual webs define planes which extend in directions which make an acute angle with an axis parallel with the axis of the pivot shaft, these webs being inter-connected by transverse webs which extend substantially parallel with the said axis parallel with the axis of the pivot shaft.

9. An arrangement according to Claim 8 wherein at least some of the transverse webs are provided with reinforcing buttresses.

10. An arrangement according to Claim 8 or 9 wherein the transverse web extending between the two groups of webs is of substantially triangular form.

11. A lever for use in a safety-belt arrangement according to any one of Claims 1 to 9, said lever comprising means defining or adapted to engage a clamping shoe, spaced apart means adapted to engage the pivot shaft and an intermediate portion extending between the means to engage the clamping shoe and the means to engage the pivot shaft, the intermediate portion comprising a plurality of webs, the webs comprising two groups of webs, the two groups of webs diverging from the ends thereof adjacent the means defining or adapted to engage the clamping shoe.

12. A lever according to Claim 10 wherein the webs form, at their ends adjacent the means defining or adapted to engage the clamping shoe, a substantially uniform corrugated pattern.

13. A lever according to Claim 11 wherein the corrugated pattern is such that individual webs extend in directions which make an acute angle with an axis parallel with the axis of the pivot shaft, these webs being interconnected by transverse webs which extend substantially parallel with the said axis parallel with the axis of the pivot shaft.

14. A lever according to Claim 12 wherein at least some of the transverse webs are provided with reinforcing buttresses.

15. A lever according to Claim 12 or 13 wherein the transverse web extending between the two groups of webs is of substantially triangular form.

16. A safety-belt arrangement substantially as herein described with reference to and as shown in the accompanying drawings.

17. A lever substantially as herein described with reference to and as shown in the accompanying drawings.

18. Any novel feature or combination of features disclosed herein.