Abstract:
A seat belt tensioner includes a guide, which has a pair of opposing plates connected by a connector, a wire, a first end of which extends upward to be connected to a seat belt, a central portion of which is curved to extend around the connector, and a retracting mechanism, which is connected to the second end of the wire and is operated by an external signal in an emergency. Here, the connector is integrally formed with at least one of the plates. Thus, the seat belt tensioner enables structural simplification, easy assembly, and a reduction in the number of parts.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to Korean Application No. 10-2008-0037347 filed Apr. 22, 2008, the entire contents of which is incorporated herein for all purposes by this reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates, in general, to a seat belt tensioner that increases the restraining force of a seat belt in order to protect a passenger in the event that a vehicle is involved in a collision. 
         [0004]    2. Description of Related Art 
         [0005]    In the event that a vehicle is involved in a collision, a passenger is often thrown forward with a considerable force, even when wearing a seat belt. A seat belt tensioner is a mechanism that increases the restraining force of a seat belt to protect the passenger before this forward throwing phenomenon occurs. 
         [0006]    A seat belt tensioner will generally be described with reference to the seat belt mechanism shown in  FIG. 1 . 
         [0007]    Typically, the seat belt mechanism is designed so that, when a buckle tongue  3  of the seat belt is fastened to a buckle  4  fixed on the side of a seat  1 , an upper belt B 1  restrains a passenger from the shoulder to the waist across the chest, and a lower belt B 2  restrains the waist of the passenger. A belt tensioner  5  is connected to the upper belt B 1 , and is mounted in a center pillar trim  2 . The lower belt B 2  is fixedly installed below the belt tensioner  5  in the center pillar trim  2 . 
         [0008]    In this manner, when the belt tensioner  5  is installed on the upper belt B 1  only, the upper belt B 1  is first tensioned by the belt tensioner  5  in the event of the collision, and then the lower belt B 2  performs restraint. Thus, according to the circumstances, the lower belt B 2  is loose in spite of the operation of the belt tensioner  5 , so that the hips and knees of the passenger move forward. In order to solve this problem, it is necessary to install the belt tensioner  5  on either the buckle  4  or the fixed end of the lower belt B 2 . The present invention particularly relates to a belt tensioner  5  that is to be mounted at this position. 
         [0009]    Meanwhile, in conjunction with the present invention, Japanese Patent Application Publication No. 1996-164821 (published on Jun. 28, 1996), and U.S. Patent Application Publication No. 2003-0090101 (published on May 15, 2003) can be referred to as cross references. 
         [0010]    The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    Accordingly, various aspects of the present invention has been made keeping in mind the above problems and provide for a seat belt tensioner capable of rapidly pulling a lower belt, i.e. a waist belt, in an emergency to protect a passenger. 
         [0012]    Other aspects of the present invention provide for a seat belt tensioner which is structurally simple and easy to assemble. 
         [0013]    Other aspects of the present invention provide for a seat belt tensioner having a reduced number of parts. 
         [0014]    Various aspects of the present invention are directed to a seat belt tensioner including a guide having a pair of opposing plates connected by a connector, a wire, a first end of which extends upward to be connected to a seat belt, and a central portion of which is curved to extend around the connector, and/or a retracting mechanism, which is connected to a second end of the wire and is operated by an external signal in an emergency. The connector may be integrally formed with at least one of the plates. 
         [0015]    The connector may be formed by a burring process, in which one of the plates is provided with a hole and is then forcibly pressed to protrude around the hole. 
         [0016]    The at least one of the plates may include at least one segmented flange, which supports the wire extending around the connector on an outer side of the wire. 
         [0017]    The first end of the wire may be surrounded by a helical spring in order to increase linearity thereof. 
         [0018]    The spring may include a horizontal extension at a lower end thereof which supports one end of the wire at an oblique angle. 
         [0019]    The pair of plates may be fastened to each other by a plurality of fastening members, and the horizontal extension part is placed on the fastening members and further includes a hook engaging one of the fastening members. 
         [0020]    The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  illustrates a seat belt mechanism having a seat belt tensioner. 
           [0022]      FIG. 2  illustrates a seat belt tensioner according to various aspects of the present invention. 
           [0023]      FIG. 3  illustrates the internal structure of the seat belt tension of  FIG. 2 . 
           [0024]      FIG. 4  is an exploded perspective view illustrating the guide of the of the seat belt tension of  FIG. 3 . 
           [0025]      FIG. 5  illustrates the spring of a seat belt tensioner according to various aspects of the present invention. 
           [0026]      FIG. 6  illustrates the state in which the spring of FIG. S is mounted on a seat belt tensioner. 
       
    
    
       [0027]    It should be understood that the appended drawings are not necessarily to scale and present a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
         [0028]    In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
         [0030]    As for the entire structure of a seat belt tensioner illustrated in  FIGS. 2 through 4 , the seat belt tensioner generally comprises a wire  20 , one end of which is connected to a seat belt (e.g., B 2 ), a guide  30 , around which the wire  20  is guided, and a retracting mechanism  40 , which is connected to the other end of the wire  20 . 
         [0031]    The wire  20  is required to be rigid in a longitudinal direction. For example, the wire  20  can be a steel wire rope, comprising several stands of twisted wire. One end of the wire  20  extends upwards to be connected to a buckle  11  via a coupler  12 . The buckle  11  is coupled with a buckle tongue  7  connected to a lower belt (e.g., B 2 ). Alternatively, one end of the wire  20  may be simply fixedly connected to the lower belt via the coupler  12 , instead of the connection between the buckle and the buckle tongue. One end of the wire  20  is housed in a housing  10 . One end of the wire  20  is surrounded by a spring  50 . This spring  50  will be described below. 
         [0032]    The guide  30  functions to fix the seat belt tensioner to a vehicle (e.g. the seat or the inside of a center pillar). This guide  30  causes one end of the wire  20  to be turned at an acute angle with respect to the other end of the wire  20  and to thereby be in line with the lower belt. This guide  30  has a structure in which a pair of opposing plates  30   a  and  30   b  is interconnected by a connector  31 . This connector  31  is formed by a burring process, in which the first plate  30   a  is provided with a hole  32   a  when manufactured, and is then forcibly pressed to protrude around the hole  32   a.  One will appreciate that other suitable metal forming processes may be utilized such as deep drawing. 
         [0033]    The wire  20  is wound on the outer circumference of the connector  31  of the guide  30 . The first plate  30   a  is provided with at least one segmented flange  33 , which supports the wire  20  running or extending around the connector  31  on the outer side of the wire  20 . When abruptly pulled by the retracting mechanism  40 , the wire  20  causes proper frictional force with the connector  31  and the segmented flange  33 , and thus pulls the lower belt at a proper speed. Meanwhile, the connector  31  may be replaced with a member such as a roller. In this case, the roller must be separately manufactured, and must then be assembled with the plates  30   a  and  30   b.  As such, the roller leads to a complicated assembly, high costs, and the potential of a malfunction. In contrast, when the connector  31  is integrally formed with the plates  30   a  and  30   b  through the burring process, this leads to a simpler structure, quicker assembly, lower costs, and better performance than in the case of the roller. 
         [0034]    Meanwhile, the second plate  30   b  is provided with a hole  32   b  corresponding to the hole  32   a  in the connector  31 . The first plate  30   a  is fastened to the second plate  30   b  by a rivet  35 , which passes through the hole  32   a  in the connector  31  and the hole  32   b.  Further, the plates  30   a  and  30   b  are provided with respective through-holes  34   a  and  34   b,  through which rivets  36  are fastened. 
         [0035]    In the event of an emergency situation, such as a vehicle collision, the retracting mechanism  40  pulls the other end of the wire  20 , so that the lower belt is pulled toward the guide  30 . The other end of the wire  20  is connected to a piston  42  in a cylinder  41 . A gas generator  43  and a gas cartridge  44  are installed between the cylinder  41  and the guide  30 , which gas generator may be activated in response to an emergency by an external signal S from a controller  45  or other suitable device. The gas generator  43  and the gas cartridge  44  are operated in an emergency, thereby forcing the piston  42  to be instantaneously pushed backward by gas pressure. One will appreciate that retracting mechanism  40  can be variously configured. 
         [0036]    The spring  50 , surrounding one end of the wire  20 , will be described with reference to  FIGS. 5 and 6 . 
         [0037]    The spring  50 , serving to increase the linearity of one end of the wire  20 , has a spirally coiled shape. Meanwhile, the spring  50  has a horizontal extension part  51  at a lower end thereof which supports one end of the wire  20  at an oblique angle. The horizontal extension part  51  extends perpendicular to the longitudinal direction of the spring  50 , and is longer than the radius of the remaining turns of the spring  50 . This horizontal extension part  51  is placed on the rivets  36 , connecting the upper ends of the plates  30   a  and  30   b  of the guide  30 , and allows one end of the wire  20  to maintain a constant angle without leaning toward the other end of the wire  20  (i.e. in the direction in which one end of the wire  20  moves away from the other end of the wire  20 ). Further, the horizontal extension part  51  of the spring  50  has a hook  52 , which engages, an in various embodiments is hooked on one of the rivets  36  such that one end of the wire  20  can constantly maintain an oblique angle. 
         [0038]    Although an exemplary embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 
         [0039]    For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inside”, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
         [0040]    The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.