KR100839295B1 - Seat belt pretensioner - Google Patents

Abstract

The pretensioner for a three-point seat belt has a cylinder 79 configured to be attached to a structural member of the vehicle and a piston disposed in the cylinder 79. The piston can move translationally relative to the cylinder 79 in the pretensioning direction. The flexible member 50 is configured in a curved shape with the seat belt webbing attached. The flexible member 50 has a first end that can be pulled by the piston and a second end that is releasably connected to the outside of the cylinder 79 so that the piston is translated relative to the cylinder 79. When moved, the second end of the flexible member moves translationally relative to the cylinder 79 along the outside of the cylinder 79.

Description

Pretensioner for three points seat belts {SEAT BELT PRETENSIONER}

The present invention relates to a pretensioner for a vehicle seat belt.

The seat belt includes the length of the seat belt webbing connected to the load bearing portion of the vehicle at three points. One end is bolted to a threshold on one side of the seat, configured to pass laterally across the hip portion of the vehicle occupant with a buckle mechanism secured to the vehicle on the opposite side of the seat, diagonally passing the body of the vehicle occupant Traversed to reach the other anchor point on the B pillar of the door. The buckle mechanism engages a buckle tongue slidably attached to the webbing.

In order to increase the comfort of the vehicle occupant restrained by the seat belt, a retractor is attached to the filler end of the webbing. The retractor is biased to keep the webbing around the vehicle occupant relatively taut. The locking component locks the retractor against webbing pay out in the event of a crash. The pretensioner quickly pulls any looseness that may have occurred in the seat belt to tighten the seat belt around the vehicle occupant in the event of a crash. This more accurately positions the vehicle occupant on the seat to maximize secondary safety restraints such as seat belt protection and airbags.

Pretensioners use a force reservoir, such as a gas generator, that is operated pyrotechnically to provide a magnitude of thrust sufficient to tighten the seat belt. Conventional known pretensioners can use a rotating means to wind the belt webbing by rotating the retractor spool in the webbing rewind direction.

Pretensioners tend to be large in size and are very difficult to use for driver and front passenger seats in two-door vehicles because of the need for access to the rear of the vehicle past the front seats. Conventional retractor pretensioner mechanisms in the front seats of two-door vehicles cause unacceptable obstructions.

Seat movement is greater in two-door vehicles than in four-door vehicles to provide access to the rear seat and to accommodate the threshold ends of the webbing that are attached to the so-called slider bars instead of being bolted to the floor normally. . This allows the threshold end of the webbing to move back and forth in the longitudinal direction to promote rear seat access and front seat movement. The present invention provides an improved pretensioning mechanism that can be used in two door, front seat arrangements.

Summary of the Invention

According to the present invention, there is provided a pretensioner for a three-point seat belt comprising a cylinder that can be attached to a structural member of a vehicle and a piston disposed in the cylinder. The piston can move in the cylinder in the pretensioning direction. The flexible member is configured in a curved shape with the seat belt webbing attached. The flexible member has a first end that can be pulled by the piston and a second end that is releasably connected to the outside of the cylinder so that when the piston moves relative to the cylinder, the second end of the flexible member also moves along the outside of the cylinder. Go against.

1 is a schematic side view of a pretensioner according to a first embodiment of the present invention;

2 is an enlarged side view of a portion of the pretensioner of FIG. 1 before pretensioning;

3 is an enlarged side view of a portion of the pretensioner of FIG. 1 after pretensioning;

4 is a side view showing a modified configuration of the pretensioner of FIG. 1;

5 is an exploded perspective view of the carriage and rail components of the pretensioner of FIG. 1;

6 is a schematic side view of a second embodiment,

7 is a side view of a third embodiment,

8 is a perspective view of the pretensioner of FIG. 7, FIG.

9 is a perspective view of a fourth embodiment.

In FIG. 1, the slider bar 10 is positioned adjacent to the front seat 12 of the vehicle, with the end of the seat belt webbing 14 passing around the slider bar 10. , It moves freely forward and backward along the slider bar 10.

The seat belt webbing 14 is of conventional design and has one end attached to a retractor mounted to a structural member of the vehicle, such as a vehicle side pillar (not shown), adjacent to the seat. The webbing passes through the shoulder support attached to the side pillars and has a buckle tongue insertable into a buckle (not shown) located on the other side of the seat.

In use, the seat belt webbing 14 is in the load bearing position shown in FIG. 1 at one end of the slider bar 10. When the seat belt is not in use, the end of the webbing 14 moves backward along the slider bar 10 so as not to interfere with the vehicle's access to the rear seat.

As used in the specification and claims, it should be understood that directions and positions such as "rear" and "front" relate to the front and rear of the vehicle in which the seat belt system and pretensioner are installed.

One end of the slider bar 10 is attached to a carriage 16 mounted to the rail 18. The use of rails is particularly useful because in a simple manner and without the need for complicated or bulky rotating parts, the action of pretensioning can be constrained by linear motion in one direction. The cable 20 extends between the carriage 16 and the pyrotechnic unit 22. The ignition unit 22 includes a piston in the cylindrical housing and the gas generator. The gas generator is operated in a pyrotechnically manner to force the piston to the rear and to provide a propulsive force to tighten the cable 20. The gas driven piston-cylinder configuration, operated in a ignited manner, functions as a force reservoir. The ignition unit is particularly suitable for this application because it provides the driving force of the desired size over a short time. Positioning the piston and cylinder under the rail advantageously reduces the overall size of the pretensioner. The piston-cylinder configuration comprises means for allowing the second member to move only in the pretensioning direction, for example by means of latch teeth on the inside of the cylinder and at least one cooperating tooth on the piston. can do.

2 shows one configuration of the carriage 16 and the rail 18 in more detail. Rails 18 are attached at each end to a support member 26 attached to load bearing chassis member 24 by bolts 28. Such load bearing chassis member 24 may be a structural member that extends longitudinally down each side or load bearing door sill of the vehicle, and adjacent and weakly behind the rear of each vehicle door for the slider bar 10. It provides a suitable load bearing anchor zone.

Prior to pretensioning, the carriage 16 is positioned at the foremost position for normal use of the seat belt webbing 14, ie to the right of the rail 18 as shown in FIG. Upon detecting the acceleration of the vehicle exceeding a predetermined reference value, the collision sensor generates a signal indicative of a collision situation, which ignites the firing unit 22 to generate tension in the metal cable 20. Advantageously, the collision sensor is activated when the vehicle exceeds a predetermined acceleration or deceleration threshold. The tension in the cable 20 pulls the carriage 16 and slider bar 10 backwards, ie in the direction indicated by arrow A in FIG. 2. The carriage 16 may be configured to move rearward by a distance in the range of 50 mm to 150 mm depending on the size and requirements of the vehicle.

Sudden movement of the slider bar 10 backwards provides tension to the seat belt webbing 14, which tightens the webbing 14 and pulls the vehicle occupant back to the seat 12 to seat 12. Accurately positioning the vehicle occupant into the vehicle maximizes the usefulness of the seat belt and accurately positions the vehicle occupant for maximum effect of secondary restraints such as airbags.

3 shows the position of the carriage immediately after pretensioning. After the firing unit is ignited, the carriage 16 is prevented from returning to the initial position under the influence of the vehicle driver's front momentum during the collision by the latch mechanism in the second member 16 forming the carriage. This latch mechanism is shown in FIG.

5 is an exploded view illustrating the latch mechanism. The rails 18 are attached to each support member 26 by bolts 36 passing through the cylindrical holes 38 at each end and at each end of the rail 18. Bolt 36 is secured with a suitable washer or spacer and nut 56. The locking latch tooth 30 is formed on one surface of the rail 18. The carriage 16 has two end plates 40 and a base plate 42 attached to the side wall 44. The locking lever 32 extends from the base plate 42. Each of the end plate 40 and the locking lever 32 has a slot that allows the rail 18 to penetrate the center of the carriage 16.

The inner surface of the locking lever 32 contacts the teeth 30 at the surface of the rail 18 and is oriented at an angle so that the locking lever 32 can pass over the teeth 30 in one direction. The locking lever 32 has the locking edge of the inner surface of the locking lever 32 caught against the teeth 30 on the upper surface of the rail 18 if it tries to move in the opposite direction so that the carriage 16 is in the opposite direction. Biased to prevent sliding. To facilitate this, the tooth 30 may have a sawtooth shape. Locking the pretensioner against the return movement prevents loss of tension in the seat belt after the execution of the pretensioning.

The slider bar 10, the carriage 16 and the latch mechanism, the rail 18, the support member 26 and the bolts 28, 36, 26 are all preferably made of metal. Latch mechanisms are known for many seat belt restraint devices so that the pretensioners of the present invention can advantageously be constructed using standard components and manufacturing processes, thus providing a relatively low cost locking mechanism. The latch mechanism and carriage 16 can be manufactured from parts of the height adjuster that are commonly used to change the height of the belt shoulder support.

In FIG. 4, the firing unit is stored under the rail 18, and the bolt 36 and the corresponding hole 38 of the rail are used to secure the firing unit 22 with respect to the rail 18. The operation of the pretensioner of FIG. 4 is almost identical to that shown in FIG. 1, except that the cable 20 is bent 180 ° to compensate for the different orientation of the firing unit 22.

According to another embodiment described below, the slider bar function is performed by connecting the seat belt webbing to an elongate flexible member such as, for example, a cable through which the seat belt webbing passes around. One end of the cable is movable and the other end is fixed. The flexible member is preferably a loop in the form of a slider bar, which provides the webbing flexibility of movement and access to the rear of the vehicle, which is desired in a two-door device.

6 shows that the slider bar of the first embodiment has been replaced with a flexible cable 50. Flexible cable 50 is generally a slider bar shaped loop that provides flexibility of movement and seat rear webbing access to the seat belt webbing, which is desired in two-door vehicle devices. (loop) The flexible cable preferably connects directly to or forms at least a part of the piston in a piston-cylinder configuration which is preferably operated in a fired manner. Such an embodiment may provide a more space saving alternative to the two-door arrangement of the pretensioner.

The seat belt webbing (not shown) is looped around the cable 50 in the same manner as the slider bar 10 of FIG. 1, with the cable having a range of activity similar to webbing mounting and at least to the rear seat of the vehicle. Provide the same degree of access.

One end 51 of the cable 50 is attached to the structural member of the vehicle, such as the threshold, and the other end is connected to the structural member of the vehicle, such as the floor of the vehicle, in particular to maintain the door shape and avoid limited access through the door. It is attached to the piston 53 of the attached piston-cylinder firing unit 52.

The cable 50 forms a loop shape as shown and may be encouraged to maintain such shape by a retaining clip or elastomeric plastic coating in normal use. The flexible elastomeric plastic tube can cause the cable 50 to increase in strength to an appropriate degree.

If the head sensor indicates that a sudden deceleration or acceleration has occurred, the ignition unit 52 is operated to release gas and push the piston along the cylinder in the direction indicated by arrow A, so that the cable 50 is broken down by 50 '. To shrink to the shape indicated by This causes the seat belt webbing mounted on the cable 50 to be pulled in the direction indicated by arrow A to perform the necessary pretensioning. Other forms of latch or non-return mechanisms may be attached to the firing unit 52.

7 is a side view of a pretensioner according to a third embodiment of the present invention. 8 is a perspective view of the pleats of FIG. 7. The cable is a double cable that is looped over the end of the cylinder and attached at the end in a releasable manner, for example by means of shearing members or mechanically releasable means. In this third embodiment, the cable 50 is attached to the piston at one end of the cylinder of the pretensioner and this cable is attached to the other end 71 of the cylinder. In this embodiment, the cable 50 is folded to form a double cable, the free end extending around the cylinder 79 of the firing unit 52 and hooked to the end 71 of the cylinder of the firing unit 52. It is formed as a loop 70. The loop 70 is fastened around the cylinder 79 by frangible or mechanically releasable means for fastening, and the restraining abutments 77, 78 in FIGS. It is shown as a plastic attachment 76 located on both longitudinal sides of 50 and mounted to the end 71 of the cylinder 79. As used in the specification and claims for the restraint pedestal, “lengthwise” is understood to refer to the longitudinal axis of the cylinder 79. When the cable 50 exerts a force above a predetermined force, one pedestal 77 is sheared to release the loop 70 to slide along the cylinder of the pretensioner. Other suitable forms of means for securing the loop 71 to the end of the cylinder will be apparent to those skilled in the art.

In FIG. 7, the fire unit 52 passes through a first mounting member 80 located at the piston end of the cylinder 79 and a second mounting member (shown in FIG. 9) located at the other end 71 of the cylinder. It is attached to a structural member of the vehicle, such as a threshold or other load bearing beam, by a fastener 72, such as an elongated threaded fastener. According to a preferred embodiment, the structural member of the vehicle is a longitudinal chassis member, such as a front threshold. A second mounting member, such as a structural member of the vehicle or a bracket bolted to the vehicle body, is fitted to the end of the cylinder to secure the pretensioner to the vehicle in a load-supporting manner. The second mounting member must withstand a load of about 15 kn as described in the standard vehicle anchorage pull test known as R14. Suitable second mounting members are apparent to those skilled in the art, one of which is shown in FIG. 9 described below.

The cable loop 70 may be surrounded by a plastic tube that allows the cable loop to slide more easily along the cylinder 79. In addition, a tie or clamp or plastic tube 75 maintains the shape of the loop 70 by enclosing the cable section and holding the double cable together. This plastic tube 75 may be longer than shown in FIGS. 7 and 8 to protect the fabric of the seat belt from chaffing by the cable. It is shown that the pair of wires 74 exit from the end 71 of the cylinder 79. These wires are for operation of the firing unit 52 located inside the cylinder 79 and can exit the cylinder at another point.

In FIG. 9, a fourth embodiment is shown, in which the cable 50 is a single cable and attached to a carriage 90 which slides along the cylinder 79 when the pretensioner is activated. The cable 50 is attached to the carriage 79 by welding the cable to a clamp or housing 91 mounted on the carriage 90. The carriage 90 is held at the end 71 of the cylinder 79 by means of a tongue 92 on the carriage 90 that fits in a recess 93 of the cylinder 79. When the firing unit 52 located inside the cylinder 79 is actuated, the pull on the cable is sufficient to shear the tongue 92 so that the carriage 90 can travel along the cylinder 79, thereby Pull the seat belt in the pretensioning direction. Alternatively, the tongue 92 can be configured to bend to perform the release of the carriage from the recess 93. Another variant uses a mechanically releasable mechanism. In FIG. 9, the second mounting member is a bracket 94 fitted to the end of the cylinder 79, which can be bolted or screwed to the structural member of the vehicle. Carriage mechanisms similar to those shown in FIG. 5 may be used.

The components of the above-described embodiments can be combined. For example, the cable 50 may be attached to a component such as a carriage 16 that slides on the rail 18 of FIG. 1. The ignition unit 52 may be connected to the carriage 16 and mounted in alignment with or under the rail 18 by another cable, such as reference numeral 20 in FIG. 1. The pretensioners according to the invention have reduced or eliminated disturbances in access to the rear seats, have a smaller package size, and are attached to suitable threshold fixing areas.

Claims (10)

In the pretensioner for a three point seat belt, A cylinder (79) configured to be attached to a structural member of a vehicle and a piston disposed within the cylinder (79), for translationally moving the piston in a pretensioning direction with respect to the cylinder (79). Sudan, A flexible member 50 configured in a curved shape with a seat belt webbing attached thereto, The flexible member 50 has a first end that can be pulled by the piston and a second end that is releasably connected to the outside of the cylinder 79 so that the piston is translational relative to the cylinder 79. Moving the second end of the flexible member transversely relative to the cylinder 79 along the outside of the cylinder 79 Pretensioner for three-point seat belts. The method of claim 1, The flexible member is a cable 50 Pretensioner for three-point seat belts. The method of claim 1, Loop 70 is located at the second end of the flexible member 50, The loop 70 extends around the outside of the cylinder 79, The loop 70 is fixed to the cylinder 79 by a frangible member 71 or a mechanically releasable member. Pretensioner for three-point seat belts. The method of claim 2, Loop 70 is located at the second end of the cable 50, The loop 70 extends around the outside of the cylinder 79, The loop 70 is fixed to the cylinder 79 by a brittle member 71 or a mechanically releasable member. Pretensioner for three-point seat belts. The method of claim 1, The second end of the flexible member 50 is attached to the carriage 90, The carriage 90 is configured to move along the outside of the cylinder 79, The carriage 90 is fixed to the cylinder 79 by a brittle member 92 or a mechanically releasable member. Pretensioner for three-point seat belts. The method of claim 2, The second end of the cable 2 is attached to the carriage 90, The carriage 90 is configured to move along the outside of the cylinder 79, The carriage 90 is fixed to the cylinder 79 by a brittle member 92 or a mechanically releasable member. Pretensioner for three-point seat belts. The method according to claim 5 or 6, And further comprising a rail 18 extending along the cylinder 79, The carriage 90 is mounted to slide on the rail 18. Pretensioner for three-point seat belts. The method of claim 7, wherein The piston and cylinder 79 are located below the rail 18 Pretensioner for three-point seat belts. The method of claim 1, Means for constraining the movement of the flexible member in a non-pretensioning direction Pretensioner for three-point seat belts. The method of claim 1, Means for moving the piston are pyrotechnically operated Pretensioner for three-point seat belts.

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