Abstract:
A belt pretensioner has a base member. The base member has an axial cavity within. An actuating member is hollow and fits within the axial cavity of the base member. The hollow actuating member telescopically slides within the axial cavity and an initiator fits within the hollow portion of the actuating member. In a critical situation such as a crash, the initiator is triggered and the expanding gasses move the actuating member. The actuating member is connected to seat belt webbing and this movement provides the necessary pretensioning of the seatbelt. In some embodiments, a locking means is used to prevent the belt pretensioner from loosening once triggered. One embodiment is provided for use with a child seat. A transversely mounted belt pretensioner embedment is also disclosed.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application is a U.S. national stage entry from co-pending International Patent Application Ser. No. PCT/CN2015/074039, filed Mar. 11, 2015 which claims priority to U.S. provisional patent application 61/967,139, filed Mar. 11, 2014, the complete disclosures of each of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to seatbelt restraint systems for motor vehicles, and more particularly, to a linear seatbelt pretensioner for a seatbelt restraint system. 
       BACKGROUND OF THE INVENTION 
       [0003]    Most passenger vehicles use a 3-point seatbelt as safety harness for restraining the occupants in the vehicles. This harness has a up-side-down “Y” shaped configuration. It has 3 mounting points. The first point is outboard lap mount, or anchorage point, while the second point is inboard lap mount, or buckle point, and the third point is the shoulder point, or D-ring point. 
         [0004]    Many prior arts have at least one linear pretensioner connected to anchorage point (usually called PLP), or buckle point (usually called PBP), or both of the seatbelt. Two of these prior arts are U.S. Pat. No. 8,132,829, and U.S. Pat. No. 7,172,218. 
         [0005]    Typical PLPs or PBPs have a pyrotechnic charge that is fired when a collision occurs, producing expanding gas which pressurizes a gas chamber within a tube, which forces a piston down the tube. The piston is connected to the belt system by a cable or strap. Movement of the piston tightens or “pretensions” the belt against the occupant. 
         [0006]    In order to retract the cable, the cable is connected to the piston and is pulled into the expanding gas chamber. Sealing the gas chamber around the flexible cable presents a difficult challenge. 
         [0007]    Patent U.S. Pat. Nos. 7,823,924, 8,528,987, and 9,090,221 have shown some so-called cable-free pretensioners presenting a better concept overcoming the sealing challenge listed above by eliminating the cable. 
         [0008]    But this technology or other known prior arts are not effective at utilizing the space of gas generator (or initiator). In other words, the axial dimension of apparatus by these technologies cannot be less than the stacking up of these three elements: the axial length of initiator, the axial length of piston, and the travel of piston (or so called actuating profile). 
       SUMMARY OF THE INVENTION 
       [0009]    A belt pretensioner has a base member. The base member has an axial cavity within. An actuating member is hollow and fits within the axial cavity of the base member. The hollow actuating member telescopically slides within the axial cavity and an initiator fits within the hollow portion of the actuating member. In a critical situation such as a crash, the initiator is triggered and the expanding gasses move the actuating member. The actuating member is connected to seat belt webbing and this movement provides the necessary pretensioning of the seatbelt. In some embodiments, a locking means is used to prevent the belt pretensioner from loosening once triggered. One embodiment is provided for use with a child seat. A transversely mounted belt pretensioner embedment is also disclosed. 
         [0010]    Other features and advantages of the instant invention will become apparent from the following description of the invention which refers to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an isometric view of a belt pretensioner according to an embodiment of the invention. 
           [0012]      FIG. 2  is a cut-away view of the belt pretensioner shown in  FIG. 1 . 
           [0013]      FIG. 3  is an exploded view of he belt pretensioner shown in  FIG. 1 . 
           [0014]      FIG. 4  is an isometric view of the belt pretensioner shown in  FIG. 1  after it has been fully actuated. 
           [0015]      FIG. 5  is a cut-away view of the fully actuated belt pretensioner shown in  FIG. 4 . 
           [0016]      FIG. 6  is an illustration of the belt pretensioner attached to a seat. 
           [0017]      FIG. 7  is an isometric view of a belt pretensioner according to an embodiment of the invention. 
           [0018]      FIG. 8  is an illustration of the internal structure of a moveable member of the belt pretensioner shown in  FIG. 7 . 
           [0019]      FIG. 9  is an illustration of a belt pretensioner mounted to a seat according to an embodiment of the invention. 
           [0020]      FIG. 10  is an isometric view of the belt pretensioner shown in  FIG. 9 . 
           [0021]      FIG. 11  is a cut-away view of the belt pretensioner shown in  FIG. 10 . 
           [0022]      FIG. 12  is an illustration of a belt pretensioner that uses a bracket and mounted to a seat according to an embodiment of the invention. 
           [0023]      FIG. 13  is an isometric view of the belt pretensioner and bracket shown in  FIG. 12 . 
           [0024]      FIG. 14  is an isometric view of a belt pretensioner attached to a cable according to an embodiment of the invention. 
           [0025]      FIG. 15  is an isometric view of a belt pretensioner according to an embodiment of the invention. 
           [0026]      FIG. 16  is a cut-away view of the belt pretensioner shown in  FIG. 15 . 
           [0027]      FIG. 17  is an isometric view of the belt pretensioner shown in  FIG. 15  attached to a child seat. 
           [0028]      FIG. 18  is a cut-away view of the belt pretensioner shown in  FIG. 17 . 
           [0029]      FIG. 19  is a cut-away view of the belt pretensioner shown in  FIG. 18  after activation. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    In the following detailed description of the invention, reference is made to the drawings in which reference numerals refer to like elements, and which are intended to show by way of illustration specific embodiments in which the invention may be practiced. It is understood that other embodiments may be utilized and that structural changes may be made without departing from the scope and spirit of the invention. 
         [0031]    The following description is merely exemplary in nature and is not intended to limit the present disclosure or its application or uses. 
         [0032]    Referring to  FIGS. 1 through 5 ,  FIG. 1  shows a schematic structure of a belt pretensioner  10  according to an embodiment of the present invention. Belt pretensioner  10  will be described using the following coordinates: z for up-down, x for fore-after, and y for cross-car direction in a vehicle (the z-axis may tilt a little bit forward around the y coordinate in actual application). 
         [0033]    Belt pretensioner  10  comprises a base member  100 , an initiator  150 , and an actuating member  200 . It may also have a locking means  400 .  FIG. 2  shows a 3D view with the section cut along the y-z plane and  FIG. 3  shows an exploded view. 
         [0034]    Belt pretensioner  10  is connected using a free-end of a 3-point seatbelt to replace a conventional anchorage of the seatbelt, as described in the following paragraphs. Of course other seatbelt configurations are possible. 
         [0035]    Base member  100  has an axial cavity  110  which passes through from the top to the bottom of base member  100 . Axial cavity  110  is peripherally bounded by wall  116 . Axial cavity  110  usually has a shoulder  114  at its top. Base member  100  usually has at least one auxiliary tunnel  120  usually parallel to axial cavity  110 . Base member  100  usually also has at least one hole  130  which is fixed to a seat  600  or a body structure (not shown) of a vehicle (not shown) through at least one fastener  140 . Base member  100  may also have at least one hole  126  for locking engagement function discussed soon. Base member  100  is made from extruded aluminum; however, any suitable material and manufacturing processes may be used. 
         [0036]    As seen in  FIG. 3 , actuating member  200  has an actuating body  210  that telescopically interacts with axial cavity  110 . Unlike other conventional actuating bodies, which is usually a solid piston, actuating body  210  is a hollow cylinder having a one end open and the other end closed. Actuating body  210  has a cavity  212  that encompasses initiator  150 . In other terms, initiator  150  is enveloped by a shank wall  214  and bottom end  216  of actuating body  210  in an un-deployed situation. Actuating member  200  can also have an actuating profile  208 , and can also have at least one auxiliary tube portion  220 , which is engaged with auxiliary tunnel  120 . 
         [0037]    Initiator  150  is secured with a top end  112  that is ideally airtight. More specifically, a axial shoulder  114  of axial cavity  110  engages with an initiator shoulder  152  of initiator  150 . The lower end is the only exit for air fluid communication for axial cavity  110 , and is closed by actuating body  210  of actuating member  200 . Actuating member  200  can be moved in and out (meaning up and down) telescopically along the axial direction of axial cavity  110 , which allows belt pretensioner  10  to maintain a basically air tight condition throughout use (or to maintain a condition of being as air tight as possible throughout use.) 
         [0038]    In other words, base member  100 , actuating member  200  and initiator  150  overlap with each other along their axial direction in the un-deployed geometry, while initiator  150  resides in the center and is enveloped by actuating body  210 , and by base member  100 . In their radial dimension, initiator  150  is the smallest of three, and usually cavity  110  of base member  100  is bigger than actuating body  210  of actuating member  200 , but also work if their sizes are reversed. A belt webbing  500  can be attached to actuating profile  208  of actuating member  200  and tensioned directly by actuating profile  208 . 
         [0039]    In an embodiment of the present invention, webbing  500  is first fixed to an outboard side of base member  100  through a cross member  502  and two spacers  504 , and folded back around the bottom of actuating profile  208  of actuating member  200 , then U-turned to the inboard side of base member  100 , then extended back upward toward to buckle side. With this setting, actuating member  200  is not fixed with webbing  500  directly, but essentially operates like a movable pulley on webbing  500 . Actuating profile  208  plays the role of the movable pulley. Thus, the linear travel of the main body of webbing is approximately twice the travel of actuating member  200  ( FIG. 4 ). 
         [0040]    Base member  100  usually has a hole, or opening  130 , with which base member  100  can be fixed with a seat or vehicle structure (not shown) directly with fastener  140 . In practice, belt pretensioner  10  can act on any location of the seatbelt routing, but typically acts on the location of the anchorage. 
         [0041]    Comparisons between  FIGS. 1 and 4 , and between  FIGS. 2 and 5  show how webbing  500  is tightened. When initiator  150  is fired, high-pressure gases  11   8  are generated by initiator  150  and moves actuating member  200  downward a distance L, which in turn moves the main webbing section through the U-turn approximately twice the distance of L (2L), therefore tightening the belt as shown in  FIGS. 4 and 5 . 
         [0042]    When initiator  150  is fired, a bottom end  156  of initiator  150  ( FIG. 5 ) is broken by erupting high pressure gas  118 . Sometimes a shank wall  154  of initiator  150  also expands significantly, which may grip shank wall  214  to stop or retard the telescoping movement of actuating member  200 . Therefore, a restraint tube  158  can be added between shank wall  154  of initiator  150  and shank wall  214  to separate their direct contact. 
         [0043]      FIGS. 1 and 3  show that locking means  400  can be added between base member  1   00  and actuating member  200 . As seen in  FIG. 3 , in this embodiment, a pin  402  is slidably engaged with a basically laterally oriented hole  222  on auxiliary tube portion  220 . Pin  402  can be installed in auxiliary tube portion  220  through its cavity, and a spring  404  is added inside the cavity of auxiliary tube portion  220  to push pin  402  away unless a top of pin  406  of pin  402  touch the inside wall of auxiliary tunnel  120 . 
         [0044]    After actuating member  200  is actuated and telescoped to some extent, pin  402  will engage with an auxiliary tunnel hole  126  of auxiliary tunnel  120 , meaning that pin  402  will move away a little bit more unless a locking means shoulder  408  touches the edge of hole  222 . When pin  402  is engaged with auxiliary tunnel hole  126 , actuating member  200  is locked with said base member  100 , meaning that it cannot be telescoped out or retreat back, which retains the tightened condition the webbing after actuation. 
         [0045]    Instead of being attached to actuating member  200  as illustrated above. Said locking means  400  can also be attached to base member  100 , similar to locking means of most height adjusters available in the seatbelt market today. 
         [0046]    Actuating profile  208  can be detachable, and then be fixed to actuating body  210  by a fastener  218 . A cotter pin  508  can be fixed with actuating profile  208  to hold a u-turn section of webbing  500  for reducing slack in webbing  500 . 
         [0047]    Since sparks may be produced from gaps both at the top and bottom of axial cavity  110  when initiator  150  is fired, a fire-retardant coating can be added on the surfaces of webbing  500  near belt pretensioner  10 . Another option provides a sheet of foil or other thin fire isolating sheet added between webbing  500  and belt pretensioner  10 . 
         [0048]    Another embodiment is shown in  FIG. 6  in which belt pretensioner  10  is not directly fixed to a seat  600 , but through a media bracket  602  in between. 
         [0049]    The embodiment shown in  FIGS. 7 and 8 , laterally mounts initiator  150  to an actuating member  202 .  FIG. 8  shows the internal structure actuating member  202 . A webbing  520  is shown having a narrowed end in this embodiment. 
         [0050]    Referring now to  FIGS. 9 and 10 , an embodiment is illustrated in which a belt pretensioner  1200  is shown in different orientation and location. Belt pretensioner  1200  is generally orientated along the y-axis (cross-car direction) of the car. A seat  1100  has a side frame  1110  and a cross member  1120 . Belt pretensioner  1200  is secured to cross member  1120  directly, or through a media member  1240 . 
         [0051]    Referring to  FIG. 10 , pretensioner  1200  has a base member  1210  and a movable member  1220 . The locking means in this embodiment utilizes a linear one-way clutch. 
         [0052]    A locking wedge portion  1228  is fixed to a first end of auxiliary tube portion  1226  of movable member  1220 , and a locking member (a roller)  1232  is installed between locking wedge portion  1228  and an inside wall of an auxiliary tunnel  1216  of a base member  1210 . A retainer  1233  prevents locking member  1232  from rolling out. 
         [0053]    In a critical situation, such as a frontal crash, a firing signal will fire initiator  1250  ( FIG. 11 ) at the location between base member  1210  and movable member  1220  which drives movable member  1220  to the right in a direction shown as Al in  FIG. 9 . An anchorage end  1272  of a seatbelt webbing  1270  is fixed with movable member  1220  through a bracket  1224 , and this movement pulls anchorage end  1272  in direction A 1 , which in turn pulls the next section in a direction A 2  which pretensions the belt portion crossing the abdomen of the occupant (not shown). 
         [0054]    During a frontal crash, the occupant moves forward with respect to the vehicle and the seat, the seatbelt will try to move movable member  1220  in the direction opposite to that of pretensioning, especially after the pretensioning, and the one-way clutch, as discussed above, will stop any loosening shortly after overcoming a small amount of free play. 
         [0055]    Now referring to  FIGS. 12 and 13 , the free end of webbing  1270  is fixed with seat  600  and webbing  1270  enters a hole  608  on seat  600 , then makes a U-turn and returns to the main routing towards to the buckle side of seat  600 . The U-turn section of webbing  1270  wraps around a cross-tube portion  1274  of a bracket  1236 , which is fixed to movable member  1200 . 
         [0056]    Referring now to  FIG. 14 , belt pretensioner  10  is shown having a base member  105 , an actuating member  206 , a cable  510 , a connector  520 , and webbing  500 . It is installed in a typical prior art configuration, but the tube, or base member of this invention is much shorter compared with prior art. Belt pretensioner  10  is secured to the vehicle through an opening  132 . A free end of cable  510  is fixed to a lower side of base member  105  by wrapping around actuating member  206  forming a U-turn. An upper portion of cable  510  is guided by a cable guide  142  and then routed upward to connector  520  which joins webbing  500 . 
         [0057]    In this embodiment, connector  520  can be replaced by a conventional seatbelt buckle, which is engaged to a latch plate slidably connected to a middle section of webbing  500 . In this case, belt pretensioner  10  plays the role of PBP. Cable  510  can be replaced by a media webbing (not shown) when belt pretensioner device  10  plays the role of PBP in seats other than the first row. 
         [0058]    Referring now to  FIGS. 15 through 19 , a belt pretensioner  2100  is shown applied to a child seat  2310 . Child seat  2310  has a back portion  2314  and cushion portion  2312 . Child seat  2310  is oriented in a rear facing situation in this case for later illustration. 
         [0059]    The typical situation of routing an independent seatbelt for use with a child seat (usually called child restraint system or CRS) is known in the art; (such as U.S. Pat. No. 8,240,772B2, and US20130175835A1). It usually has what is called 5-point configuration. These 5 points of CRS converge to a single point at a front connector. Between these 5 points and the converged point of front connector, two shoulder portions, two abdomen portions and an adjustment portion are formed. A webbing  2500  has a proximal end  2502  for adjusting the length to fit with various sizes of child occupants. Proximal end  2502  is usually located between upper legs of a child occupant and is usually locked after adjustment. The adjustment portion usually has a “L” shape having a bottom sub-portion and a back sub-portion. The pretensioner  2100  can be applied at each of these sub-portions, or at their turning location. For a better understanding, the following paragraph describes how the pretensioner  2100  is applied at the location of bottom sub-portion. 
         [0060]    A belt pretensioner  2100  has a base member  2010  and a movable member  2200 . Webbing  2500  is shown with proximal end  2502  of webbing  2500  routed beneath base member  2010 , towards the direction of back portion  2314 , then going up and then turning about  90  degrees by routing pin  2413 . Routing pin  2413  is connected to cushion portion  2312  with a bracket  2414 . 
         [0061]    A spacer  2418  may be used to create space for routing pin  2413  when inserted between base member  2010  and cushion portion  2312 . After passing around routing pin  2413 , webbing  2500  is routed toward the back side of back portion  2314 , then turns about 90 degrees and runs up to be connected to a back connector (not shown) which is connected to two shoulder portions of webbing  2500 . 
         [0062]      FIG. 19  shows the situation after belt pretensioner  2100  is fired, moveable member  2200  is pushed outward from base member  2010  which forces webbing  2500  to form a “Z” shaped portion. Since proximal end of  2502  and pin  2413  are fixed, the distal end  2505  and the back connector are then pulled down, then the two shoulder portions (not shown, but known in the art) of webbing  2500  are tensioned. 
         [0063]    An initiator  2150  is connected by harness to a battery of the vehicle, or an independent battery installed in the child seat. As is known in the art, an inertia sensor (can be a ball-in-tube style) and a control unit can be connected to the related circuit for deciding the fire condition. 
         [0064]    The present invention  10  can also be applied to what is called 4-point seatbelt system, which can be seen at vehicles for special purposes, such as fire fighting vehicles, race-cars or even airplanes, or fast-boats. This 4-point seatbelt is almost the same as a 5-point seatbelt, with the main difference being the elimination the adjustment portion, or bottom portion of the seatbelt webbing 
         [0065]    Although the instant invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art.