KR100839294B1 - Seat belt pretensioner - Google Patents

Abstract

The seat belt pretensioner acts on the door of the three-point seat belt. The fixing member 79 of the pretensioner is configured to be fixed to the load supporting portion of the vehicle. The movable member 99 is connected to the threshold end of the seat belt 14 and is slidable with respect to the fixing member. The movable member 99 moves in the longitudinal direction relative to the fixing member 79 to move the threshold end of the seat belt in the pretensioning direction in response to a signal from the collision sensor. In this way, the threshold end of the seat belt moves freely along the connecting member in use which limits the seat occupant and / or when the seat belt is not taut from the pretensioning operation.

Description

Pretensioner for three points seat belts {SEAT BELT PRETENSIONER}

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

Conventionally, the seat belt comprises the length of the seat belt webbing connected to the load bearing portion of the vehicle at three points. Typically, one end is bolted to a threshold on one side of the seat and is 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, Cross the body diagonally 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. This releases the webbing under relatively low loads such that limited movement of the vehicle occupant reaches, for example, in-car entertainment control or storage compartments. The retractor is biased to keep the webbing around the vehicle occupant relatively taut, and a locking component is included to lock the retractor against webbing loosening when a collision is detected. For example, an acceleration sensor works when the vehicle accelerates or decelerates, meaning crash.

In recent years, pretensioners have been introduced to tension the seat belt around the vehicle occupant in the event of a collision by quickly pulling in the length of the seat belt webbing. This tensions any looseness that may occur in the seat belt and helps to more accurately position the vehicle occupant on the seat to maximize secondary safety restraints such as seat belt protection and airbags.

The pretensioner ideally uses a force reservoir, such as a gas generator, that is operated pyrotechnically to provide a magnitude of thrust sufficient to tighten the seat belt before the collision completely occurs. Conventional known pretensioners use a rotating means to wind the length of the seat belt webbing, for example by rotating the retractor spool in the webbing rewinding direction, to wind the required length of the webbing before retractor locking against webbing loosening. Can be.

Known pretensioners, however, 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 seat. The use of conventional retractor pretensioner mechanisms in the front seats of two-door vehicles causes unacceptable obstructions.

The seat movement provides access to the rear seat and instead of being bolted to the floor, instead of in a four-door vehicle to accommodate the threshold end of the webbing that is usually attached to a so-called slider bar of well-known design. Bigger in two-door vehicles. 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.

Summary of the Invention

The present invention provides an improved pretensioning mechanism that can be used in two door, front seat arrangements.

It is difficult to design a pretensioner suitable for use with the slider bar and / or for use in a three door vehicle without disturbing the function of the slider bar or without access to the rear seat.

The present invention provides an improved pretensioning device.

According to the present invention, there is provided a seat belt pretensioner which acts on the threshold end of a three-point seat belt, comprising: a fixing member configured to be fixed to a load supporting portion of the vehicle, a movable member connected to the threshold end of the seat belt, and a longitudinal direction with respect to the movable member A means for moving the threshold end of the seat belt in the pretensioning direction in response to a signal from the collision sensor, the elongate connecting member being slidably attached to the threshold end of the seat belt for moving the movable member in the in-direction; A pretensioner is provided. In this way, the threshold end of the seat belt moves freely along the connecting member when the seat belt is not under tension from use in constraining the seat occupant and / or from pretensioning operation.

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 pretensioner according to a second embodiment of the present invention;

7 is a side view of a pretensioner according to a third embodiment of the present invention;

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

9 is a perspective view of a pretensioner according to a fourth embodiment of the present invention;

10 is a side view of a pretensioner according to a fifth embodiment of the present invention;

11A and 11B are side views of a pretensioner according to a sixth embodiment of the present invention;

12A and 12B are side views of a pretensioner according to a seventh embodiment of the present invention;

13 is a side view of a front vehicle seat according to another embodiment of the present invention;

14A and 14B are front views of a front vehicle seat according to another embodiment of the present invention.

As used in the specification and claims, terms such as "forward" and "rear", "forward" and "rear", and similar terms refer to the front of a vehicle in which the seat belt pretensioning device of the present invention is installed. And back is to be understood. Further, as used in the specification and claims, terms such as "up" and "down", "high" and "low" refer to the ceiling of the passenger compartment of a vehicle equipped with the seat belt pretensioning device of the present invention. And floor is to be understood.

In the first embodiment of FIG. 1, the slider bar 10 is positioned adjacent to the front seat 12 of the vehicle. One end of the seat belt webbing 14 passes around the slider bar 10 and moves freely back and forth along the slider bar 10.

The seat belt webbing 14 is of conventional design and is attached at one end 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 has a buckle tongue that passes through a shoulder support that is also attached to the side pillar and is 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.

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 is of a known type and comprises 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. Such ignition units are particularly suitable for this application because they provide 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 a load bearing chassis member 24 may be a structural member extending longitudinally down each side of the vehicle or below a load bearing door sill, and in the known three-door vehicle the rear of each vehicle door Adjacent and weakly providing an appropriate load bearing anchor zone for the slider bar 10.

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. However, 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 opposite. Biased to prevent sliding in the direction. To facilitate this, the tooth 30 may have a sawtooth shape. Locking the pretensioner against the return movement in this way prevents the 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 ignition unit is shown stored under the rail 18, with the bolt 36 and the corresponding aperture 38 of the rail being used to secure the ignition unit 22 relative to the rail 18. do. 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. Thus, 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. to be. 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. Thus, this 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, and the cable is mobile mobility similar to webbing mounting. And at least the same degree of access to the rear seat of the vehicle.

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 in the figure and may be encouraged to maintain such shape by a retaining clip or elastomeric plastic coating in normal use. Alternatively, 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.

FIG. 7 is a side view of a pretensioner according to a third embodiment of the present invention, and FIG. 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 means of 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. For all embodiments disclosed herein, 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 also 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. Alternatively, a carriage mechanism similar to that shown in FIG. 5 can be used.

FIG. 10 shows a fifth embodiment of the present invention wherein the end of the seat belt webbing 14 is mounted to the cylinder 79 of the pretensioning unit 22 rather than the cable 50. This end of the webbing 14 is, for example, of a hollow cylindrical shape, preferably made of plastic material, arranged to move freely along the length of the cylinder 79 in normal use to provide access to the rear seat. Attached by looping around the outer surface of bobbin 99. Thus, in this embodiment the cylinder 79 operates efficiently as a slider bar.

This fifth embodiment is similar to the embodiment shown in Figs. The loop 70 is fastened around the cylinder 79 by means for a brittle or mechanically releasable fixation, and in FIGS. 7, 8 and 10 restraints 77 on both longitudinal sides of the cable 50. 78, it is shown as a plastic attachment 76 mounted over the end 71 of the cylinder 79. If the collision sensor indicates that a sudden deceleration or acceleration has occurred, the pretensioning unit 22 acts in a igniting manner to release the gas and push the piston along the cylinder 79 in the direction indicated by the arrow B, resulting in a cable 50 ) Causes the one pedestal 77 to shear when exerting a force greater than the predetermined force, thereby releasing the loop 70 to pretensioner in the direction indicated by arrow A (opposite to the direction indicated by arrow B). Slide along the cylinder (79). Since the cable loop 70 moves along the cylinder 79, it forces the plastic bobbin 99 along the cylinder 79, pulling the end of the webbing 14 in the pretensioning direction indicated by arrow A. Pull.

11A and 11B show a sixth embodiment of the present invention. In FIG. 11A, the pretensioning unit 22 is located at one end of the slider bar 10. The seat belt webbing 14 is attached by looping around the outer surface of a hollow cylindrical bobbin 99 slidably mounted on the slider bar 10, for example, and the pretensioning unit upon restraining the seat occupant during normal use. At the opposite end of slider bar 10 relative to 22, the forward position shown in FIG. 11A is taken. The portion of the slider bar 10 on which the bobbin 99 slides is oriented at least substantially parallel and is preferably parallel to the longitudinal axis of the cylinder of the pretensioning unit 22. The cable 20 connects the piston of the pretensioning unit 22 to the bobbin 99. If the collision sensor indicates that a sudden deceleration or acceleration has occurred, the pretensioning unit 22 is operated in a ignition manner and pulls the cable 20 so that the bobbin 99 and the webbing 14 are shown by arrows A. FIG. Located in a pretensioning position as shown. 11A shows the belt 14 in the pretensioning position and FIG. 11B shows after the pretensioning. Of course, the pretensioning unit 22 can be mounted in any orientation under or adjacent the slider bar, for example to save space, and a cable guide can be provided to avoid snagging.

12A and 12B show a seventh embodiment of the present invention. The pretensioning unit 22 is located at one end of the slider bar 10 as in FIGS. 11A and 11B. However, in this embodiment, the end of the seat belt webbing 14 loops directly around the slider bar 10 so that it can move freely along the length of the slider bar in normal use, requiring access to the rear seat of the three-door vehicle. Allow the seat belt webbing to move away from the vehicle door. The cable 20 is connected to the piston of the pretensioning unit 22 and forms a loop that surrounds the seat belt webbing 14 in the region of the slider bar 10. If the collision sensor indicates that a sudden deceleration or acceleration has occurred, the pretensioning unit 22 causes the looped cable 20 to be pulled toward the pretensioning unit 22 in the direction indicated by the arrow A, so that webbing Tension around 14 and pull back the webbing along the slider bar 10 in the pretensioning direction indicated by arrow A to the pretensioned position as shown in FIG. 12B.

13 illustrates a load bearing webbing guide 104 that can be used to increase the performance of any of the pretensioning devices of any of the embodiments described above. A three-point seat belt 14 connected to the pretensioning unit 22 via a load bearing webbing guide 104 such that the seat belt webbing follows a path substantially parallel to the line of action of the force caused by the pretensioning unit. It shows that the vehicle occupant 106 is seated on the front seat 12 fixed in position. The path of the webbing 14 ′ without the load bearing webbing guide 104 is shown in dashed lines, and the path of the webbing 14 with the load bearing webbing guide 104 is shown in solid lines. The load bearing webbing guide 104 causes the webbing 14 to move along the line more parallel and closer to the line of action of the force caused by the pretensioning unit 22 (ie within 30 °) The performance is improved compared to the line of the webbing 14 ′ without the support guide 104. This increase in performance means that the physically shorter pretensioning unit 22 can be used to achieve the same pretensioning effect, i.e. it can pull the webbing loose of the same length.

14A and 14B show how more space can be saved by installing the pretensioning unit 22 under the seat 12. It can be used in three door, four door and five door vehicles.

In Fig. 14A, the vehicle seat 12 is fixed with a three-point seat belt. The seat belt webbing 14 passes upward from the retractor 111 to the webbing guide 112 on the B pillar of the vehicle. The seat belt webbing 14 then passes across the shoulders and torso of a vehicle occupant (not shown) to a buckle anchor point 113. Finally, the seat belt webbing 14 passes across the knee of the seat occupant to the threshold anchor point 114 and is connected to a pretensioning unit 22 installed below the seat 12. The pretensioning unit 22 is mounted to the load bearing portion of the vehicle under the seat 12 or to the seat 12 itself, although other shapes and applications will be apparent to those skilled in the art, as shown in FIGS. The shape of any of the embodiments shown in figure 9 may be taken. 14B shows the same configuration as FIG. 14A after pretensioning. The pretensioning unit 22 can tighten the webbing 14 by pulling the end of the webbing 14 in the direction indicated by the arrow A, and can tighten the webbing looseness to about 140 mm.

Although not shown in FIGS. 14A and 14B, the slider bar 10 may be incorporated, and a cable may be used as the slider bar as in the embodiment described above.

With respect to the embodiment shown in relation to FIGS. 10-14B, the movement of the end of the seat belt webbing 14, for example, by a latch tooth and at least one cooperative tooth located inside the cylinder, is in a non-tensioning direction. It is preferable to provide a means for restraining. Locking the pretensioner against the return movement in this way prevents the loss of tension in the seat belt after the pretensioning is performed. Although already described herein, latch mechanisms are known for many seat belt restraint devices, so that the pretensioners of the present invention can advantageously be constructed using standard parts and manufacturing processes, thereby providing a relatively low cost locking mechanism.

Of course, the components of the above-described and disclosed embodiments may 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 firing unit 52 may be mounted in alignment with or under the rail 18 after being connected to the carriage 16 by another cable, such as reference numeral 20 of FIG. 1.

According to the present invention, a pretensioner can be constructed which reduces or eliminates access to the rear seat, has a smaller package size, and is attached to a suitable threshold fixing area.

Claims (15)

In the pretensioner for a three point seat belt, Means (22) for moving said piston in a pretensioning direction longitudinally relative to said cylinder, said cylinder including a cylinder (79) configured to be attached to a structural member of a vehicle; Means for attachment 99 located outside of the cylinder to which the seat belt webbing 14 is attached, The means for seat belt webbing and attachment can move freely in the longitudinal direction with respect to the cylinder, unless the means for moving the piston in the pretensioning direction with respect to the cylinder is not actuated. Means (10) for guiding said seat belt webbing in a direction longitudinal to the cylinder, A pull extending from the piston when the means for moving the piston is actuated to cause the seat belt webbing 14 to move in a pretensioning direction longitudinally relative to the cylinder along the guiding means Comprising means (20, 50) for Pretensioner for three-point seat belts. The method of claim 1, The means for attachment comprises a hollow bobbin 99 in which the seat belt webbing is looped around. Pretensioner for three-point seat belts. The method of claim 1, The means for guiding is the outer surface of the cylinder 79 Pretensioner for three-point seat belts. The method of claim 2, The means for guiding is the outer surface of the cylinder 79 and the bobbin 99 slides along the outer surface of the cylinder. Pretensioner for three-point seat belts. The method of claim 2, The means for guiding is the outer surface of the cylinder 79, the bobbin 99 slides along the outer surface of the cylinder, one end of the means for pulling is attached to the piston, and the pulling The other end of the means for fastening is attached to the carriage, the carriage being configured to move along the outside of the cylinder, the carriage being fixed to the cylinder by a brittle member 76, so that the means for moving the piston is actuated. When the brittle member 76 releases the carriage, the carriage pushes the bobbin 99 along the outer surface of the cylinder 79 in the pretensioning direction. Pretensioner for three-point seat belts. The method of claim 1, The means for guiding is the slider bar 10 Pretensioner for three-point seat belts. The method of claim 2, The means for guiding is a slider bar and the bobbin slides along the slider bar. Pretensioner for three-point seat belts. The method of claim 2, The means for guiding is a slider bar 10, the bobbin 99 slides along the slider bar and the means for pulling 20 extends from the piston to the bobbin. Pretensioner for three-point seat belts. The method of claim 2, The means for guiding is a slider bar, the bobbin slides along the slider bar, the means for pulling extends from the piston to the bobbin, and the bobbin is parallel to the longitudinal axis of the cylinder. Sliding along a portion of the oriented slider bar Pretensioner for three-point seat belts. delete The method of claim 1, Means for limiting movement of the end of the seat belt webbing in the non-pretensioning direction in accordance with the operation of the means for moving the piston; Pretensioner for three-point seat belts. The method of claim 1, The pretensioner is installed in the car, The cylinder is connected to the structural member of the vehicle such that the cylinder extends longitudinally with respect to the vehicle. Pretensioner for three-point seat belts. The method of claim 1, The pretensioner is installed below the seating surface of the car seat so that the cylinder does not extend longitudinally with respect to the car. Pretensioner for three-point seat belts. The method of claim 1, The pretensioner is installed in the car, The cylinder is connected to a structural member of the vehicle such that the cylinder extends in a longitudinal direction with respect to the vehicle, The load bearing webbing guide allows the seat belt webbing to follow a path substantially parallel to the line of action of the force caused by the pretensioner when the means for moving the piston are actuated. Pretensioner for three-point seat belts. The method of claim 1, The pretensioner is installed in the car, The cylinder is connected to a structural member of the vehicle such that the cylinder extends in a longitudinal direction with respect to the vehicle, The load bearing webbing guide allows the seat belt webbing to follow a parallel path within 30 ° to the line of action of the force caused by the pretensioner when the means for moving the piston are actuated. Pretensioner for three-point seat belts.

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