Seat belt buckle attachment device

Abstract

The invention relates to a fastening device (100) for a seat belt buckle (52) of a motor vehicle seat, comprising: - a loop strand (110), - a rod (120) mounted on a rigid structure of the motor vehicle, and - a system for slidingly movable mounting (101) of the loop strand along said rod, which is adapted to block said sliding when a tensile force greater than a threshold is exerted on the loop strand, this sliding movable mounting system comprising: ¤ a support (130), ¤ coupling means (150) of the support to the seat, ¤ a cam (140) mounted so as to rotate on the support between a position for wedging the rod (120) and a rest position, and ¤ elastic return means (160) of said cam to the rest position. Figure for the abstract: Fig.2

Description

Title of the invention: Seat belt buckle attachment device Technical field of the invention

[0001] The present invention relates generally to the safety of the occupants of a motor vehicle.

[0002] It relates more particularly to a fastening device for a seat belt buckle of a motor vehicle seat, comprising: - a loop-strand adapted to receive said seat belt buckle, - a rod adapted to be mounted on a rigid structure of the motor vehicle, and - a system for movable mounting of the loop strand along said rod, which is adapted to block this sliding when a tensile force greater than a threshold is exerted on the loop strand.

[0003] It also relates to a seat equipped with such a fastening device and a vehicle equipped with such a seat. State of the art

[0004] It is known to mount the front seats of a motor vehicle with front-to-back sliding mobility and up-and-down movement mobility.

[0005] Such a seat generally comprises a seat, a slide system (with two parallel fixed rails which are fixed to the floor, and two movable rails which are capable of sliding along the two aforementioned rails), and raising means which connect the seat to the movable rails and which make it possible to adjust the height of the seat relative to the floor.

[0006] These raising means are generally made up of two pairs of front and rear connecting rods connecting the two movable rails to the seat so as to form two deformable parallelograms.

[0007] Such a seat is equipped with a seat belt buckle strand comprising a rod and, at its upper end, a clasp capable of receiving and locking the bolt of a seat belt buckle.

[0008] This loop strand must be fixed to the floor or to the seat rails to withstand the regulatory constraints in the event of an accident. It is understood that if it were fixed to the seat structure, both this seat structure and the connecting rods would have to be sized to withstand the aforementioned constraints, so that the seat would be particularly heavy and expensive to produce.

[0009] The disadvantage then is that the clasp does not follow the height movement of the seat structure, which is detrimental to the overall ergonomics of the vehicle. Indeed, when the seat is in the high position, the clasp is located too low to be easily accessible. In addition, when the seat occupant has fastened his seat belt and wants to raise the seat, the latter tightens around his pelvis and prevents him from raising the seat.

[0010] In order to address this issue, document US20140265503 discloses a seat whose loop-end again comprises a rod and a clasp, but whose lower end of the rod is coupled to the seat structure so as to follow the vertical movement of the latter. More precisely, this lower end is housed in a housing fixed to the seat. This same housing is crossed by a rigid rod which extends parallel to the rod of the loop-end, and whose lower end is articulated on one of the movable rails. A spring is sandwiched between the rigid rod and the rod to keep them apart from each other, in particular when the seat and the loop-end rise, and the housing slides along the rigid rod.On the other hand, when a tensile force greater than a threshold is exerted on the loop-strand (typically in the event of an accident), the spring is compressed so that the rod comes to bear against a toothed portion of the movable rod. This toothed portion then makes it possible to block the sliding of the rigid rod in the housing, so that the tensile force is transmitted directly from the clasp to the movable rail, via the rigid rod.

[0011] The disadvantage of this system is that it may happen that the cooperation between the rod and the toothed portion of the rigid rod is not carried out in a satisfactory manner. Presentation of the invention

[0012] In order to overcome the aforementioned drawback of the state of the art, the present invention proposes to use a cam instead of the spring.

[0013] More particularly, the invention proposes a hanging device as defined in the introduction, in which the system for sliding the loop strand along the rod comprises: - a support, - means of coupling the support to a movable part of the seat (preferably to the seat), - a cam mounted so as to be movable in rotation on the support between a wedging position in which it blocks the rod (preferably against the support) and a rest position in which it releases the sliding of the rod relative to the support, the loop strand being secured to said cam in such a way that it tends to bring said cam back into the wedging position when a tensile force is exerted on the loop strand, and - means for elastically returning said cam to the rest position.

[0014] Thus, thanks to the invention, the cam is held in the rest position as long as the loop seat belt buckle is not subject to abnormal stress. Therefore, the cam does not prevent the loop strand from moving up and down along the rod. On the other hand, the loop strand forces the cam to press against the rod when the seat belt buckle is subjected to high stresses (in the event of an accident), which allows the loop strand to be locked in relation to the rod and therefore to transmit the forces undergone by this loop strand to the floor of the vehicle, without passing through the seat.

[0015] Other advantageous and non-limiting characteristics of the attachment device according to the invention, taken individually or in all technically possible combinations, are the following: - the coupling means are adapted to deform or yield when said tensile force exceeds a breaking threshold; - the coupling means comprise a connecting rod, one end of which is articulated on the support around a first pivot axis, and another end of which is adapted to be articulated on the seat around a second pivot axis parallel to the first pivot axis; - said rod is adapted to be articulated on the rigid structure; - the buckle strand comprises a clasp adapted to receive said seat belt buckle and a rod secured to said cam; - the rod is articulated on said cam; - said cam being mounted so as to be movable in rotation on the support around an axis of rotation and said rod being articulated on said cam around a rocking axis, said axes of rotation and rocking are parallel and extend in a plane inclined relative to a longitudinal axis of said rod.

[0016] The invention also relates to a motor vehicle seat adapted to be mounted on a floor of the motor vehicle, comprising: - a seat forming a mobile part, - a file, - a raising system allowing the height of the seat to be varied in relation to the floor, and - a hanging device as mentioned above.

[0017] Preferably, the seat further comprises a slide system which comprises two fixed rails adapted to be fixed to the floor, two movable rails mounted to slide on the two fixed rails, a member for blocking the sliding of the movable rails relative to the fixed rails, and means for deactivating the blocking means, the rod being mounted on one of the movable rails.

[0018] The invention also relates to a motor vehicle comprising a floor and a seat as mentioned above.

[0019] Of course, the various characteristics, variants and embodiments of the invention may be combined with each other in various combinations provided that they are not incompatible or mutually exclusive. Detailed description of the invention

[0020] The description which follows with reference to the appended drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

[0021] In the attached drawings:

[0022] [Fig-1] is a schematic view of a seat according to the invention, illustrated in two different configurations;

[0023] [Fig.2] is a schematic view of a device for attaching the seat of [Fig.l], in resting position;

[0024] [Fig.3] is a schematic view of the attachment device of [Fig.2], in position of jamming.

[0025] A motor vehicle (car, bus, truck, boat, airplane, etc.) generally comprises a chassis and bodywork elements which together delimit a passenger compartment. Here, the vehicle will be considered to be a car.

[0026] In [Fig.l], there is shown a seat intended to be installed in the passenger compartment of such a motor vehicle and to be fixed to the chassis of this motor vehicle, and more precisely on the floor 2 of this motor vehicle.

[0027] In the remainder of the description, the terms “front” and “rear” will be used in relation to the motor vehicle, the front part of an element designating the part of this element which is located on the side of the hood of the vehicle and the rear part designating the part of this element which is located on the opposite side.

[0028] The terms “lower” (or “bottom”) and “upper” (or “top”) will be used in the same way, the lower part of an element designating the part of this element which is located on the side of the floor 2 of the vehicle and the upper part designating the part of this element which is located on the side of the roof of the vehicle.

[0029] The adjective "longitudinal" will apply to a direction or axis oriented from the front to the rear of the vehicle, parallel to the direction of travel of the vehicle when the steering wheel is in the neutral position.

[0030] The adjective "transverse" will apply to a direction or axis oriented orthogonally to the longitudinal axes and horizontally when the vehicle is traveling on a horizontal road.

[0031] The term "articulated" will be used to designate a coupling between two elements without translational mobility, but with at least rotational mobility. In practice, it will hereinafter designate a coupling by simple pivot connection. But as a variant, it could also designate a ball joint.

[0032] A joint can be obtained in various ways. It can, for example, be operated by a screw which passes through an opening provided in a first of the elements and which screws into the second element, in which case a tube (called a bearing) or a bearing (ball, needle, etc.) will be provided between the screw and the opening to ensure the freedom of pivoting of the two elements relative to each other.

[0033] As shown in [Fig.l], the seat 1 conventionally comprises a seat 10 and a backrest 20, each comprising a frame and a padding attached to the frame.

[0034] Each of these frames is for example formed of metal parts (not shown) fixed together. Here, it will be considered that the frame of the backrest 20 and the frame of the seat 10 each comprise two metal lateral sides, rigidly connected together by metal connecting elements. Of course, as a variant, these frames could be presented differently, for example in the form of plastic shells.

[0035] In the context of the invention, the seat 10 is designed to be mounted so as to be mobile in height on the floor 2, between low positions (shown in dotted lines) and high positions (shown in solid lines). The seat 1 comprises for this purpose a raising system 30.

[0036] Preferably, the seat 10 is also designed to be mounted so as to be movable back and forth on the floor 2. The seat 1 comprises a slide system 40 for this purpose.

[0037] These raising systems 30 and slide 40 are well known. They could come in very varied forms. Here, we can briefly describe, by way of example, one embodiment of these systems.

[0038] In this embodiment, the slide system 40 comprises two fixed rails 41 which extend longitudinally, parallel to each other, on the floor 2. These two fixed rails 41 are equipped with means for fixing to the floor. In practice, they can be equipped with screws for fixing them to the floor.

[0039] The slide system 40 further comprises two movable rails 42 which are respectively mounted to slide on the two fixed rails 4L. These fixed and movable rails have shapes such that the only degree of freedom of the movable rails 42 relative to the fixed rails 41 is a sliding movement along a longitudinal axis.

[0040] The slide system 40 also comprises means for blocking this sliding mobility, formed for example by a notched accessory (not shown), mounted movably on at least one of the movable rails and adapted to hook onto notches provided in correspondence on the associated fixed rail.

[0041] A means of operating this notched accessory, such as a lever accessible to the occupant of the seat 1, then makes it possible, when the occupant of the seat wishes to move his seat 1 forward or backward, to move the notches of this accessory away from those of the fixed rail to release the sliding mobility of the seat 10.

[0042] Alternatively, the slide system could be motorized.

[0043] In the example illustrated, the raising system 30, for its part, comprises two pairs of connecting rods 31, 32. Each connecting rod 31, 32 is articulated, on one side, on one of the movable rails 42 and, on the other, on one of the lateral flanks of the frame of the seat 10, around a transverse axis. The two connecting rods 31, 32 of each pair of connecting rods extend substantially parallel to each other, between one of the movable rails 42 and one of the lateral flanks, so as to form with the latter a sort of deformable parallelogram. Thus the seat 10 can move relative to the floor 2 following a so-called rotary translation movement, in which the seat maintains a substantially constant inclination and describes an arc-of-circle movement relative to the floor 2.

[0044] The raising system 30 also comprises operating means (not shown) for controlling the raising or lowering of the seat 10. These operating means are preferably manual, but they could alternatively be motorized. Here they comprise a lever (not visible) associated with a pumping system for forcing the connecting rods to pivot in one direction or the other.

[0045] Here, the backrest 20 is directly mounted on the seat. It may be fixed to the latter or articulated on the latter around a transverse axis, so as to be able to tilt. Alternatively, the backrest could be mounted on the movable rails.

[0046] The seat 1 is also equipped with a seat belt system 50.

[0047] This seat belt system could be of the two-point type (with a lap strap attached on either side of the seat occupant's pelvis).

[0048] Here, it will be considered rather that it is a three-point system. Such a system firstly comprises a strap 51, one end of which is fixed on a first side of the seat 1, at the level of the seat 10, and the other end of which is wound in a reel fixed to the chassis of the vehicle, on this same side of the seat, at the height of the top of the backrest 20. It also comprises a loop 52 which is threaded onto the strap 51 and which has a bolt.

[0049] The seat 1 is equipped, on the other side of the seat, at the height of the seat 10, with a hooking device 100 for this seat belt buckle 52.

[0050] This attachment device 100 is shown in detail in [Fig.2]. It comprises a loop-strand 110 which is here in a so-called tulip shape, with a rod 111 at the upper end of which is a clasp 112 which is adapted to receive said bolt to block it. This clasp incorporates an unlocking button allowing the bolt to be released if necessary.

[0051] These different elements being well known to those skilled in the art, they will not be described here in more detail.

[0052] On the other hand, the system for attaching the rod 111 in the vehicle can be described.

[0053] The rod 111 in practice has attachment means at its lower end. These attachment means are not fixed to the floor 2 or the seat rails since otherwise the clasp 112 would extend at a fixed height relative to the floor 2.

[0054] It is contrary provided, according to the invention, that the clasp 112 can rise or fall, as a result of the rise or fall of the seat 10 of the seat 1.

[0055] For this, according to a particularly advantageous characteristic of the invention, the attachment device 100 comprises a rod 120 mounted on a rigid structure of the motor vehicle, and a system 101 for mounting the loop strand 110 on this rod 120, which operates with a cam and which allows the loop strand 110 to slide along this rod 120 except in the event of an accident.

[0056] The structure on which the rod 120 is mounted is described as rigid in the sense that it is able to withstand greater stresses than the seat 10. As will be clearly described below, the rod 120 is designed to be subjected to high stresses in the event of an accident (provided that the impact does not exceed the standards for which the seat is designed). It is therefore designed not to deform plastically in the event of an accident and to be fixed to an element which does not deform further.

[0057] In practice, the rod 120 is mounted either on the floor 2 of the vehicle, or on one of the fixed rails 41, or, preferably, on one of the movable rails 42.

[0058] Here, the rod 120 is mounted on one of the movable rails 42. Thus, the entire attachment device 100 moves forward or backward as the seat 10 moves forward or backward.

[0059] The rod 120 could be fixed (without any mobility) on this movable rail 42, in which case it would preferably be chosen to be elastically flexible.

[0060] However, it will be preferable to use a rigid rod 120, so that this rod 120 will preferably be articulated on the movable rail 42, around a transverse axis called pivot axis A5.

[0061] In the example illustrated in [Fig.2], the rod 120 is in the form of a profiled bar, that is to say a bar having a constant section over a major part of its length.

[0062] This bar is for example formed from a metal strip (typically steel) of rectangular section.

[0063] This bar is extended, on the side of its lower end, by an eyelet 121 which allows, via an axis, to articulate it on the movable rail 42.

[0064] The system 101 for mounting the loop-strand 110 on the rod 120 is then provided to allow the loop-strand 110 to slide along the rod 120 as the seat 10 rises or falls relative to the floor 2. On the other hand, it is designed to block this sliding when a tensile force Fl greater than a tensile threshold Flmax is exerted on the loop strand 110 (which typically happens in the event of an accident).

[0065] This tensile force Fl corresponds to the force which is exerted on the loop-strand 110 by the occupant of the seat 1 (via his seat belt 51 and the buckle 52) in the event of a frontal impact. As shown in [Fig.3], it can be modeled by a force applied to the clasp 112, along the axis of the rod 111, in the direction opposite to the rod 111.

[0066] The aforementioned traction threshold Flmax will preferably be greater than 10 N. It therefore corresponds to the limit from which the system will activate to block sliding.

[0067] As shown in [Fig. 2], the mounting system 101 firstly comprises a support 130. This support 130 could be in various forms. It will be considered here that it has the shape of a tube of rectangular section, with two main walls 131 and two side walls 132. It delimits a passage which is crossed by the rod 120. This passage preferably has a width, measured between its main walls 131, which is equal, apart from the sliding clearance, to the thickness of the rod 120 (measured along the pivot axis A5). Thus, the rod 120 can slide freely between the two main walls 131.

[0068] Here, this rod 120 is designed to slide against one of the side walls 132. Thus, the support 130 can rise and fall along this rod 120. It is designed to follow the movement of the seat 10, when the raising system 30 is actuated.

[0069] It could be provided that the support is fixed directly to the seat 10 (or to the backrest 20).

[0070] But here, a coupling means 150 is provided between the support 130 and a movable part in height of the seat (here the seat 10). In practice, a connecting rod 151 is provided, a lower end of which is articulated on the support 130 around a transverse axis (called first pivot axis A1), and an upper end of which is articulated on the seat 10 around another transverse axis (called second pivot axis A2).

[0071] Thus, the raising or lowering of the seat 10 necessarily causes the support 130 to rise or fall along the rod 120.

[0072] The rod 120 carries, on its upper end, a stop 122 preventing the support 130 from coming out of the rod 120.

[0073] Preferably, the connecting rod 151 and / or one of its two articulations is described as fusible in the sense that it is designed to yield when the tensile force Fl exceeds a breaking threshold Flrapt, preferably greater than 1000 N. This breaking threshold Flrapt will for example be of the order of 400 daN. It will in any case be greater than the breaking threshold traction Flmax.

[0074] Thus, in the event of an accident, the connecting rod 151 will give way, then all of the forces applied to the loop strand 110 will be able to propagate towards the rod 120, which will prevent any deformation of the seat 10.

[0075] Alternatively, it could be provided that the connecting rod 151 deforms elastically or plastically in the event of an accident.

[0076] To keep the rod 120 pressed against the side wall 132 of the support 130, it may optionally be possible to use a guide (not shown) fixed to the support 130.

[0077] To lock the support 130 relative to the rod 120 only when the traction threshold Flmax is exceeded, a cam 140 is provided.

[0078] This cam 140 is housed in the passage delimited by the support 130. It has a thickness equal, apart from the operating clearance, to the width of this passage. It is mounted freely movable in rotation in this passage, around a transverse axis called axis of rotation A3. For this purpose, it has an opening threaded onto a rod fixed to the support 130.

[0079] This cam 140 has a non-circular contour around this axis of rotation A3. Here, it has an ovoid contour, with a base and a nose. The base of the cam 140 bears against the rod 120, while its nose points away from the rod 120.

[0080] In a first position, called the rest position, the cam 140 is either held at a distance from the rod 120, or resting against this rod 120, in which case the force that it exerts on the latter does not prevent the rod 120 from sliding through the passage delimited by the support 130.

[0081] The cam 140 is held in this position, on the one hand, by a stop 161, and, on the other hand, by an elastic return means 160 which brings it back into contact with this stop 61 and holds it there, as long as the traction force Fl remains substantially lower than the traction threshold Flmax.

[0082] Here, the stop 161 is fixed to the support 130, under the cam 140. The elastic return means 160 is formed by a tension spring, one end of which is fixed to the support 130 and the other of which is fixed to the nose of the cam 140. Of course, as a variant, other means could be used. Typically, a torsion spring placed around the axis of rotation A3 could be used.

[0083] The rod 111 of the loop-strand 110 is then attached to the cam 140, so that the tensile force F1 tends to move the cam 140 away from its stop 161. It is then attached there opposite the base of the cam relative to the axis of rotation A3. In practice, it is articulated on the cam 140 around a transverse axis called the rocking axis A4.

[0084] It will be noted in this regard that the traction threshold Flmax will depend on: - the shape of the cam 140, - the distance between the attachment point of the rod 111 on the cam 140 and the axis of rotation A3, - the distance between the spring attachment point on cam 140 and the rotation axis A3, and - the stiffness of this spring.

[0085] When the tensile force Fl exceeds the tensile threshold Flmax, the cam 140 pivots about the axis of rotation A3. The cam 140 has a shape such that, during this movement, its radius measured between its axis of rotation A3 and the point of contact of the cam 140 on the rod 120 increases. Thus, the cam 140 presses against the rod 120 so that the latter is blocked between the cam 140 and the side wall 132 of the support 130. It is then considered that the cam 140 is in the jammed position.

[0086] It is therefore understood that the traction threshold corresponds to the limit from which the springs deform sufficiently to block the translation of the rod 120.

[0087] In practice, the resting and wedging positions can be very close to each other.

[0088] It will be noted that the force exerted by the cam 140 on the rod 120 will then be all the greater as the tensile force Fl is important, which will ensure effective blocking of the rod 120 between the support 130 and the cam 140.

[0089] In this jammed position, as shown by the dotted line in [Fig. 3], the tensile force Fl exerted by the bolt on the loop strand 110 will be fully transmitted to the rod 120, and therefore to the fixed rail 42, via the cam 140 (after breaking of the articulation of the connecting rod 151 on the seat).

[0090] The present invention is in no way limited to the embodiment described and shown, but those skilled in the art will be able to provide any variant in accordance with the invention.

[0091] Typically, the loop-strand could be without a rod (111), in which case the clasp would be articulated directly on the cam.

[0092] According to another variant, the support could be designed to be coupled to the seat without a fuse.

[0093] As a further variant, the support could be articulated directly on the base (or in the upper part of a connecting rod), without a connecting rod.

[0094] According to another variant, the rod could be flexible and its lower end could be fixed to the cam.

[0095] According to another variant, the rod could have a circular section, in which case the edge of the cam would be hollowed out, at least on the side of its base, to match the shape of the rod.

[0096] In the example illustrated in the figures, both the sides of the rod and the edge of the cam and the inner face of the support are smooth. But as a variant, it is possible to envisage that these elements have reliefs forming, for example, a micro-notch. In this way, the blocking of the rod along the rod in the event of an accident will be more effective, particularly if a lubricant has flowed along the rod.

Claims

Claims

1. Attachment device (100) for a seat belt buckle (52) of a motor vehicle seat (1), comprising: - a loop strand (110) which is adapted to receive said seat belt buckle (52), - a rod (120) which is adapted to be mounted on a rigid structure (42) of the motor vehicle, and - a sliding movable mounting system (101) of the loop strand (110) along said rod (120), which is adapted to block the sliding of the loop strand (110) along said rod (120) when a tensile force (Fl) greater than a threshold (Flmax) is exerted on the loop strand (110), characterized in that the sliding movable mounting system (101) comprises: - a support (130), - coupling means (150) of the support (130) to a movable part (10) of the seat (1),- a cam (140) mounted so as to rotate on the support (130) between a wedging position in which it blocks the rod (120) relative to the support (130) and a rest position in which it releases the sliding of the rod (120) relative to the support (130), the loop strand (110) being secured to said cam (140) in such a way that it tends to return said cam (140) to the wedging position when a tensile force (F1) is exerted on the loop strand (110), and - elastic return means (160) of said cam (140) to the rest position.,

2. Attachment device (100) according to claim 1, wherein the coupling means (150) are adapted to deform or yield when said tensile force (Fl) exceeds a breaking threshold (Flrupt).

3. Attachment device (100) according to claim 1 or 2, in which the coupling means (150) comprise a connecting rod (151) one end of which is articulated on the support (130) around a first pivot axis (A1), and another end of which is adapted to be articulated on the movable part (10) of the seat around a second pivot axis (A2) parallel to the first pivot axis (A1).

4. Hanging device (100) according to one of claims 1 to 3, wherein said rod (120) is adapted to be articulated on the structure rigid (42).

5. Attachment device (100) according to one of claims 1 to 4, in which the loop-strand (110) comprises a clasp (112) adapted to receive said seat belt buckle (52) and a rod (111) secured to said cam (140).

6. A hooking device (100) according to claim 5, wherein the rod (111) is hinged to said cam (140).

7. Attachment device (100) according to one of claims 1 to 6, wherein said cam (140) is mounted to rotate on the support (130) about an axis of rotation (A3) and said rod (111) is articulated on said cam (140) about a tilt axis (A4), said axes of rotation (A3) and tilt (A4) are parallel and extend in a plane inclined relative to a longitudinal axis of said rod (120).

8. Motor vehicle seat (1) adapted to be mounted on a floor (2) of the motor vehicle, comprising: - a seat forming a movable part (10), - a backrest (20), - a raising system (30) making it possible to vary the height of the seat relative to the floor (2), characterized in that it comprises a hooking device (100) according to one of claims 1 to 7.

9. Seat according to claim 8, comprising a slide system (40) which comprises two fixed rails (41) adapted to be fixed to the floor (2), two movable rails (42) mounted to slide on the two fixed rails (41), a member for blocking the sliding of the movable rails (42) relative to the fixed rails (41), and means for deactivating the blocking means, the rod (200) being mounted on one of the movable rails (42).

10. Motor vehicle comprising a floor (2) and a seat (1) according to one of claims 8 and 9.

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