EP0079835B1 - Safety belt buckle, especially for motor vehicles - Google Patents

Description

The present invention relates to devices intended to retain a passenger in a motor vehicle in his seat in the event of sudden deceleration thereof, for example during an emergency braking or a collision. More particularly, the invention relates to a loop which in a device of the type indicated is intended to removably attach a strand of a safety strap to a fixed point on the vehicle body, by means of a tongue forming lock bolt.

Such loops have been described in particular in patent FR-A-2,349,296 and the certificate of addition FR-A-2,379,995 referring to this patent, both filed in the name of the Applicant.

These known loops include a housing in which is placed a bracket in the form of a stirrup which is intended to be fixed to a fixed retaining means relative to the body of the vehicle and which defines between its wings, a lane for the bolt emerging at one end of this stirrup, the loop further comprising a locking member mounted oscillating in the stirrup around an axis which is perpendicular to the wings of this stirrup, as well as a stop member mounted sliding in these wings and erasable by means of a control button, against the action of an elastic return device.

The bolt is retained in the loop by a projecting part of the locking member which prevents the bolt from being withdrawn from the guide passage into which it enters, for example by entering an opening made in the bolt. During a strong traction on the strap tending to remove the bolt from the buckle, this projecting part comes to cooperate with a stop edge formed in the bottom of the support stirrup, possibly by elastic deformation of the axis of oscillation of the locking member in the stirrup, which makes it possible to obtain a high efficiency of the buckle and a considerable retaining force of the bolt, despite the simplicity and the small dimensions of the buckle. However, this construction requires compliance with fairly tight tolerances during manufacture. Furthermore, in modern automotive technology, it is desired to reduce as much as possible the weight and size of the equipment and this at all levels and in particular in the field of safety equipment without, of course, sacrificing efficiency of this equipment.

The main object of the invention is therefore to improve the loop of the prior art listed above, in particular by creating a smaller and lighter loop, the manufacture of which can be undertaken without respecting tight tolerances.

To this end, the subject of the invention is a loop of the kind defined above which is characterized in that it further comprises locking means by bolt wedge effect in the guide passage against the internal surface of the 'soul of the stirrup, these locking means cooperating with an active inclined surface formed on said locking member.

The blocking by wedge effect results in the jamming of the bolt in the buckle with an efficiency all the greater as the pulling force on the strap is greater (in the event of sudden braking or a violent shock , for example). Furthermore, the relative position of the parts which are brought into play to achieve the wedge effect is specific for each loop, which in fact leads to a catch-up by construction of the manufacturing tolerances inherent in these parts. Thus, the loop can be produced with less precision while having a better blocking efficiency than that which could be obtained with a loop constructed according to the aforementioned prior art.

This improved efficiency allows, ultimately, for a force limit on the given strap, to reduce the size of the parts and in particular to reduce the width of the stirrup by about half compared to the aforementioned conventional loop.

According to a preferred characteristic of the invention, the locking means comprise a roller of constant circular section which by its surface of revolution is intended to come into contact on the one hand with the bolt to hold it against the inner surface of the core of the stirrup, and on the other hand, with the active inclined surface of the locking member.

According to another characteristic of the invention, the bolt has at least in one of its large faces a profiled recess in which penetrate the locking means by wedge effect.

According to another characteristic of the invention, this profiled recess of the bolt has an active surface of the same inclination as the active surface of the locking member in the locked position of the bolt, said active surfaces forming a predetermined angle between them by converging the towards each other in the direction of ejection of the bolt from the loop.

• - la fig. 1 est une vue en élévation et en coupe d'une boucle pour ceinture de sécurité réalisée selon un mode d'exécution préféré de l'invention;
• - les fig. 2, 3 et 4 sont des vues en coupe respectivement prises selon les lignes 2-2, 3-3 et 4―4 de la fig. 1;
• - la fig. 5 est une vue en coupe du bouton de commande de la boucle;
• - la fig. 6 représente une vue en perspective éclatée de celle-ci;
• - la fig. 7 est une vue en élévation schématique de cette boucle et montre le diagramme des forces agissant sur les diverses pièces qui la composent pour en expliquer le fonctionnement;
• - la fig. 8 est une vue à très grande échelle de certaines pièces de la boucle pour expliquer le fonctionnement de celle-ci en cas d'un choc très violent;
• - les fig. 9A à 9F représentent par une vue en élévation et en coupe analogue à celle de la fig. 1 mais à plus petite échelle, la boucle suivant l'invention pour en expliquer le fonctionnement dynamique;
• - les fig. 10, 11 et 12 représentent des vues en perspective et en coupe partielle de plusieurs pênes pouvant être utilisés avec la boucle suivant l'invention;
• - la fig. 13 est une vue en élévation et en coupe d'une boucle pour ceinture de sécurité conforme à l'invention, mais réalisée selon un autre mode d'exécution; et
• - la fig. 14 est une vue en coupe prise suivant la ligne 14-14 de la fig. 13.

The invention is set out below in more detail using drawings representing only one embodiment, in which:

• - fig. 1 is an elevational and sectional view of a seat belt buckle produced according to a preferred embodiment of the invention;
• - figs. 2, 3 and 4 are sectional views respectively taken along lines 2-2, 3-3 and 4―4 of FIG. 1;
• - fig. 5 is a sectional view of the loop control button;
• - fig. 6 shows an exploded perspective view thereof;
• - fig. 7 is a schematic elevation view of this loop and shows the diagram of the forces acting on the various parts which compose it to explain its operation;
• - fig. 8 is a view on a very large scale of certain parts of the loop to explain the operation of the latter in the event of a very violent shock;
• - figs. 9A to 9F represent by a view in elevation and section similar to that of FIG. 1 but on a smaller scale, the loop according to the invention to explain its dynamic operation;
• - figs. 10, 11 and 12 show perspective views and in partial section of several bolts which can be used with the buckle according to the invention;
• - fig. 13 is an elevational and sectional view of a buckle for a seat belt according to the invention, but produced according to another embodiment; and
• - fig. 14 is a sectional view taken along line 14-14 of FIG. 13.

We will first examine Figures 1 to 6 which show the loop according to the invention in its preferred embodiment.

This loop comprises a support 1 in the shape of a stirrup having a bottom 1 a and two wings 1 b and 1 c.

In the following description, the side of the loop in which a latch P is inserted (that is to say the left end in all the figures) and the rear end will be called “front end” and “side rear”. opposite of this loop.

It can be seen that the rear end of the core or bottom 1 a of the stirrup is extended by a fixing lug 2 reinforced by lateral fallen edges 3 extending in the general plane of the wings 1 b and 1 c, and provided with a central orifice 4. Between the edges 3 can be inserted the end of a retaining means 5 which can be a "peduncle" which is the member attaching the loop to the floor of the vehicle for example. Of course, this retaining means can also be a strand of strap or any other similar member.

The retaining means is pierced with an orifice 6 and is covered with a fixing plate 7 also pierced with an orifice 8 and provided with lateral notches 9 which adapt to the staircase shape of the edges 3 of the extension 2. A rivet 10 is intended to pass through the orifices 4, 6 and 8 when they are aligned in order to rigidly fix the loop with the retaining means 5.

Each of the wings 1 b and 1 c has at the front an incision 1 d in the form of a staircase and delimiting a portion of wing 1 e deformed inwards to reduce the spacing of the stirrup at this point. . At the same time, the lower edge 1f of each of these deformed portions delimits a guide passage 11 in the support 1 into which the tongue-shaped part 12 of the latch P can be inserted. Furthermore, the deformed portions 1e each have a orifice 1a, the two orifices being aligned and intended to receive a hinge pin 13 which therefore extends perpendicular to the wings 1b and 1c of the support.

Each of the wings 1b and 1c also presents an elongated lumen 1h which extends parallel to the bottom 1a of the stirrup and in which a pin 14 can slide.

Each of the wings also has, towards the rear, an orifice 1 i, the two aligned orifices thus formed being intended to receive a second articulation pin 15.

The bottom 1a of the stirrup has a roughly T-shaped cutout 16, the longest branch of which extends parallel to the wings of the stirrup.

The loop also includes a locking member 17 which has roughly the shape of a C and which has a concavity 17a, the bottom of which constitutes an active planar surface 17b. This locking member is also provided with a hole 17c for the passage of the pin 13 by means of which this locking member 17 is therefore articulated in the support 1. Furthermore, at the rear, the locking member 17 has an unlocking heel 17d whose role will be explained below.

The locking member 17 is mounted between the wings 18a and 18b of a bracing member 18 which is carried by the pin 13 passing through aligned holes 18c provided in these wings 18a and 18b. These are joined together by a connection plate 18d, the assembly of this bracing member being preferably made of a molded plastic.

An ejection member 19 is intended to slide from front to rear or vice versa on the bottom 1a of the stirrup while being guided in this movement by means of a guide tab 19a in the form of an inverted T and which is adapted to penetrate in the T-shaped hole 16 made in the bottom 1 a. This ejection member 19 has the general shape of a plate whose front edge 19b is hollowed out to adapt to the shape of the front edge 12a of the bolt P. The opposite edge of the plate has a notch 19c in which can penetrate a branch 20a of an ejection spring 20.

This is of the elastic steel wire type and it comprises, outside the branch 20a, a central part 20b constituted by a few coiled turns, part which ends in a second branch 20c generally extending in opposite direction with respect to to branch 20a of this spring. The central part 20b is engaged on the spindle 15 while being housed in a cavity 21 a (see fig. 1) of a lever 21 which is also engaged on the spindle 15 between the wings 1 b and 1 c of the stirrup and which comprises a central part 21 a of support pierced with aligned holes 21 b through which the pin 15 can pass to ensure the articulation of this lever. This comprises a first branch 21c providing a guiding function and pierced with an oblong opening 21d, while the opposite branch 21 e is in the form of an unlocking spout 21 e intended to come into contact with the heel 17d of the locking member 17, as will appear later.

The opening 21 d of the lever 21 is crossed by the tail 22a of a pusher 22 which has the general shape of a hammer, the transverse part of which is produced in the form of a claw 22b which can be engaged elastically on the pin 14 A helical spring 23 is engaged on the tail 22a while being trapped between the branch 21c of the lever 21 and the claw 22b.

The loop also has a button control 24 which is mounted sliding and straddling the wings 1b and 1c of the support 1. This button has lateral wings 24a and 24b each having at the rear a notch 24c intended to be engaged on a corresponding end of the pin 14 as well as a cavity 24d in which the corresponding end of the pin 13 can be engaged for guiding this button. The latter also includes holding cells 24e of two springs 25 for recalling the button position outwards, these springs being engaged on lugs 1 formed at the front on the wings of the support 1.

The loop finally comprises wedge blocking means which, in the embodiment shown, are formed by a roller 26 of constant circular section. This roller is housed in the space delimited by the concavity 17a of the locking member 17.

The bolt P has in its tongue 12, an imprint 12b whose profile has in cross section of the tongue 12, a flat inclined surface 12c and a rounded surface 12d of circular section and whose radius is identical to that of the roller 26 .

When the bolt P is locked in the loop, the planar surface 12c has an inclination which is identical to that of the active planar surface 17b of the locking member 17, it being understood that the angles of inclination of these surfaces are not not identical. On the contrary, in this position of the bolt P, these surfaces converge towards the front by making a determined angle with respect to the general plane of the bottom 1 a of the support 1.

As shown in fig. 1, the entire loop can be housed in a housing 27, made of plastic, for example, and produced from two half-shells assembled according to a joint plane which is parallel to that of the bottom of the support 1.

We will now examine fig. 7 which schematically represents the loop just described in the locked configuration, that is to say when the bolt P is inserted in the guide passage 11 delimited by the support and that a traction T of low value is exerted on the latch by the strap, which can occur during normal braking of the vehicle or when it is subjected to a slight impact. The force T is exerted on the bolt by the strap because the passenger retained by the latter on his seat tends to pull the bolt P out of the loop due to the inertia effect which occurs when the vehicle is decelerated. The force T is compensated by the jamming effect of the roller 26 in the following manner.

The bolt undergoes two combined actions which tend to counteract the force T. It is first of all the friction force N ϕ 1 (ϕ 1 representing the angle of friction of the bolt on the bottom 1 a of the support of the Next, the roller 26 exerts a force G on the flat surface 12c of the imprint 12b of this bolt P and this results in a friction force G ϕ 2, (p 2 being the angle of friction of the roller on the bolt P.

The bolt thus being in balance, the roller 26 must be retained by the locking member 17 by an opposing force G1 which originates at the point of contact between the roller 26 and the planar active surface 17b of the locking member 17. This force G1 generates a friction force G1 ϕ 3 (ϕ 3 being the angle of friction between the roller 26 and the active surface 17b of the locking member) and it follows that the locking member 17 tends to turn around the spindle 13 counterclockwise with a moment which is equal to the product of the resultant R and the distance h from it with respect to the axis of the hinge pin 13 .

The resultant R is counterbalanced on the one hand by the reaction A exerted by this pin on the locking member and on the other hand by the reaction generated by the application of the latter against the pin 14 (force g with force of friction g ϕ 4, ϕ 4 being the coefficient of friction between the pin and the locking member.

The transmission of force G on the locking member 17 results from a wedge effect which is generated due to the inclination of an angle a of the planar surface 17b of the concavity 17a of the locking member 17 relative to the general plane of the bottom 1a of the support 1. In the embodiment shown, the bolt present in the cavity 12b, the inclined surface 12c, arrangement which is preferred to obtain blocking security and maximum operating efficiency of the loop. The surface 12c is inclined at an angle relative to the general plane of the bottom 1a of the support 1 with a> β. As a result, the surfaces 17b and 12c converge forward. We will see below that the bolt can have imprints of various shapes or even include a hole through it right through.

If the configuration of fig. 7 corresponds to a traction T of the strap on the bolt P of a current value occurring in the case of normal braking or a slight impact, FIG. 8 represents the case of a collision in which the force T exerted on the bolt can be very large (to fix ideas of the order of 1500 kg).

We have just seen in the light of FIG. 7 that in the case of normal traction T _n on the strap, the direction of the component R _n requires the action of the pin 14 to ensure the balance of the locking member 17. But in the case of a significant pull T _i , it is assumed that the bolt undergoes a slight movement in the direction of extraction where it follows that the roller 26 pivots about its fulcrum 0 on the active surface 17b of the member locking by deforming the material thereof. The direction of the force G _n of the roller on the bolt then tends to change so that for a certain value of the force T _i , the force G _n is transformed into a force G with a friction force G ϕ 3 'whose the R component; then has a direction which passes below the axis of articulation of the spindle 13, that is to say on the other side with respect to the direction of the resultant R _µ . It can therefore be seen that under these conditions, the assembly is self-locked and the pin 14 no longer intervenes in operation.

Note that the angles a and must be defined so that point 0 is located inside the envelope defined by the coefficient of friction <p 2 of the roller 26 on the bolt P to prevent the rotation of the roller and its ascent according to arrows F1 and F2 . Of course, in fig. 8, the phenomena which occur in the event of very strong traction on the strap are shown in an exaggerated manner to better illustrate the operation, the essential being that in the case of a significant shock, the resultant R; is located below the axis of the spindle 13, so that the system becomes self-locking.

It follows from these properties of the buckle according to the invention that ultimately the effectiveness of the blocking for high tensile forces on the strap makes it possible to reduce the dimensions of the whole of the buckle, in particular in width.

We will now examine FIGS. 9A to 9F to describe in detail the operation during the introduction of the bolt and when the buckle is released.

In fig. 9A, the loop is at rest. Under these conditions, the roller 26 is supported on the front part of the ejection member 19 and the locking member is also supported on the roller. Indeed, the pin 14 is urged elastically against the locking member 17 by the spring 23 which, in turn, urges the pusher 22 forward. The ejection member 19 is held in the front position by the spring 20, a balance being obtained between the force of this spring and that of the spring 23.

If now (fig. 9B) the bolt P is introduced into the guide passage 11, the ejection member 19 is first of all biased backwards against the action of the spring 20, while '' at the same time, the roller 26 is pushed towards the rear while benefiting from the greater volume which it has in the rear part of the concavity of the member 17. The group 14 is elastically urged by the spring 23 against the member locking device which tends to pivot the latter about the axis 13 so as to maintain its contact against the roller 26.

Continuing the introduction movement (fig. 9C), the roller 26 arrives at the end of the concavity of the locking member 17. The bolt continues its introduction, slides under the roller, pushes the member again ejection until the notch formed on the bolt P is under the roller which is installed there pushed by the locking member 17 still under the action of the pin 14 (fig. 9D).

The introduction of the bolt P can then stop, the ejection member elastically urged by the spring 20, brings it back in the opposite direction to the introduction until the cooperation of the chain formed by the ejection member 19, the spring 20, the lever 21, the pusher 22, the spring 23 and the pin 24, finds its position of equilibrium (fig. 9E). To release the bolt P, it should be according to fig. 9F, to press the control button (which has not been shown in FIGS. 9A to 9F, for greater clarity) whereby the pin 14 is brought back by sliding in the lights made in the wings support. Under these conditions, the locking member can oscillate around the spindle 13 anti-clockwise by providing more space for the roller 26 which can thus go up the slope formed in the imprint of the bolt P. The latter is then ejected from the loop under the action of the springs 20 and 23. It should be noted that the lever 21 can contribute to facilitating this movement because its beak 21 e comes into contact with the heel 17d thus requesting the locking member anticlockwise.

Fig. 10 shows the tongue 12A of a bolt PA in which there is provided an imprint 28 in each face of this tongue. This imprint is of cylindrical shape whose radius is at least equal to that of the circular section of the roller 26.

Fig. 11 shows a bolt PB comprising two imprints 29 on either side of the large faces of its tongue 12B, the shape of these imprints being identical to those shown in the previous figures.

The PC bolt of fig. 12 has a tongue 12c in which a simple square hole 30 has been made, the transverse edges of which come into contact with the roller 26. It should be noted that the bolts PA to PC of FIGS. 10 to 12 can be used indifferently in both directions .

The variant of figs. 13 and 14 makes it possible to use a bolt PD, the tongue 12d of which has indentations 31 formed in the parallel edges of this tongue. In this case, the support comprises a guide passage 32 formed in the bottom 33 of a support 34 by a deformation of U-shaped section. This variant makes it possible to further reduce the width of the loop while benefiting from all the advantages which have been described above.

The preferred embodiment described above comprises a roller of constant circular section. The invention is not limited to such a wedge blocking means. To obtain the same results and guarantee all the advantages of the loop, other bodies with an external rounded surface can be used, such as a ball, a barrel-shaped member, etc.

Claims (13)

1. A safety belt buckle comprising a case (27) in which is disposed a U-sectioned support (1) adapted to be fixed to retaining means (5) fixed relative to the body of the vehicle and defining between its branches (1 b, I c), a guiding channel (11) for the bolt (P) opening out at one end of this U-sectioned support, the buckle further comprising a locking element (17) pivotally mounted in the U-sectioned support (1) on a pin which is perpendicular to the branches (1 b, 1 c) of this U-sectioned support, and a stop element (14) slidably mounted in these branches and retractable by means of a control knob (24) in opposition to the action of an elastically yieldable return device (20,23), characterised in that it further comprises wedge-action locking means (26) for locking the bolt in the guiding channel (11) against the inner surface of the web (1 a) of the U-sectioned support (1), these locking means cooperating with an active inclined surface (17b) formed on said locking element (17).

2. A buckle according to claim 1, characterised in that the locking means comprise an element (26) having in its zones contacting the bolt (P) and the locking element (17) portions having a rounded surface adapted to come respectively in contact, on one hand with the bolt (P) for maintaining it against the inner surface of the web (1 a) of the U-sectioned support (1), and, on the other hand, with the active inclined surface (17b) of the locking element (17).

3. A buckle according to claim 2, characterised in that the bolt (P) has at least one shaped recess (12b) in which the wedge-action locking means (26) penetrate.

4. A buckle according to claim 2, characterised in that the shaped recess (12b) of the bolt (P) has an active surface (12c) having the same inclination as the active surface (17b) of the locking element (17) in the locked position of the bolt (P), said active surfaces (12c, 12b) making a predetermined angle (α-β) therebetween by converging toward each other in the direction of ejection of the bolt (P) of the buckle.

5. A buckle according to claim 3, characterised in that the profile of said recess (28) of the bolt (PA) is a portion of a cylinder.

6. A buckle according to claim 3, characterised in that said recess (30) of the bolt (PC) is a throughway opening.

7. A buckle according to any one of the claims 2 to 5, whose bolt (PA, PB) comprises a tongue portion (12A, 12B) adapted to be inserted in said guiding channel (11), characterised in that a cavity (28, 29) is provided in each of the large sides of said tongue portion.

8. A buckle according to any one of the claims 2 to 5, whose bolt (PD) comprises a tongue portion (12D) adapted to be inserted in said guiding channel (11), characterised in that a cavity (31 ) is provided in one or in the two opposed edges of said tongue portion (12D), the latter being adapted to be inserted on edge in said guiding channel (32).

9. A buckle according to any one of the preceding claims, characterised in that said locking means comprise a roller (26) having a constant circular section.

10. A buckle according to any one of the claims 1 to 9, characterised in that said locking element (17) has roughly a C shape in the cavity (17a) of which is formed said active surface (17b), this locking element having extending therethrough a pivot pin (13) engaged in the branches (1 b, 1 c) of the U-sectioned support (1) close to the front edges of said branches.

11. A buckle according to claim 3, characterised in that the locking element (17) comprises an unlocking heel portion (17d) and there is further provided a lever (21) which is pivotally mounted between the branches (1 b, 1c) of the U-sectioned support (1) on a pin parallel to the pivot pin of the locking element, this lever comprising a nose portion (21 e) adapted to come into contact with the heel portion (17d) of the locking element (17) when said control knob (24) is shifted.

12. A buckle accroding to claim 11, characterised in that a return spring (20) is associated with said lever (21) so as to biase it to a position in which the nose portion (21 e) is spaced away from the locking element (17) and this spring (20) cooperates at the same time with an element (19) for ejecting the bolt (P), this ejecting element being slidably mounted in the bottom (1 a) of the U-sectioned support (1) and being biased by said spring in such manner as to urge the bolt (P) out of the guiding channel (11) when the buckle is unlocked.

13. A buckle according to claim 12, in which said stop element (14) is a pin slidably mounted in openings (1 h) respectively formed in the branches (1 b, 1 c) of the U-sectioned support (1) parallel to the guiding channel (11), said stop element being connected to a push member (22) elastically urged in opposition to the unlocking action of the buckle achieved by the control knob (24), characterised in that said push member (22) is provided with a guiding tail portion (22a) extending through one of the branches (21 c) of said lever (21).

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