Abstract:
A webbing take-up device for taking up and unwinding a webbing belt in a vehicle is provided that includes a rotatably mounted take-up shaft adapted for receiving and anchoring an end of the webbing belt, and rotatably urged in a direction for taking up the webbing belt; and a frame having a pair of leg plates opposing each other between which the take-up shaft extends. The frame further includes a connecting portion integrally extending from one leg plate to the other, and a fixing portion adapted for fastening to the vehicle, the connecting portion has a plurality of engraved portions on either side defined therein, and at least some of the engraved portions are formed as elongated holes or thinned portions having a longitudinal axis formed substantially along a direction in which tensile force is applied via the take-up shaft and leg plates when the webbing belt is unwound.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a webbing take-up device for a seat belt apparatus for restraining a vehicle occupant by means of a webbing belt. 
     2. Description of the Related Art 
     In a webbing take-up device, which is a principal portion of a seat belt apparatus which restrains a vehicle occupant by means of an elongated belt-shaped webbing belt, there is provided a take-up shaft to which one longitudinal direction end portion of the webbing belt is anchored. The take-up shaft is urged by an urging means such as a spiral coil spring in a direction in which the webbing belt is taken up. When the webbing belt which has been taken up on the take-up shaft is pulled out, the urging force from the urging means acts on the webbing belt. The urging force works as a restraining force which restrains the body of a vehicle occupant in the state in which the webbing belt is applied to the vehicle occupant. 
     The take-up shaft is supported either directly by a pair of leg plates which are formed at a frame, or indirectly via supporting members which are provided at the leg plates. Each of the leg plates is usually formed in a plate shape. In the case where the leg plates support the take-up shaft directly, the take-up shaft is supported by the leg plates in a manner in which the take-up shaft penetrates the leg plates at supporting holes or the like which are formed at the transverse direction central portion of the leg plates. On the other hand, in the case where the leg plates support the take-up shaft indirectly, the take-up shaft is supported by the leg plates in a manner in which the take-up shaft penetrates through through-holes which are formed at the transverse direction central portion of the leg plates, and is supported by supporting members attached to the leg plates. 
     One transverse direction end portion of each leg plate is integrally connected to a transverse end portion of a plate-shaped connecting portion. The webbing take-up device is mounted to a vehicle by fixing a portion of the connecting portion to a predetermined region of the vehicle by a fastening means such as a bolt. 
     When considering the fuel consumption and the like of a vehicle, it is preferable that the structural components of a webbing take-up device be as light as possible. One means for lightening the structural components of a webbing take-up device is lightening the aforementioned frame. Since the connecting portion of the frame is in a plate shape as described above, lightening of the frame can be readily attained by engraving the connecting portion to form appropriate holes or thinned portions. 
     On the other hand, when the webbing belt is pulled out, tensile force is applied to the connecting portion via the take-up shaft, the leg plates and the like. While the take-up shaft is provided corresponding to the transverse direction central portions of the leg plates as described above, the connecting portion is provided at respective ones of the transverse direction ends of the leg plates. Thus, when the webbing belt is pulled out, a torque about the portion of the connecting portion that is fixed to the vehicle is generated, which will deform the connecting portion in the direction of the torque. From the viewpoint of ensuring and maintaining the restraining force of the webbing belt, it is preferable that the connecting portion deforms as little as possible when acted on by the aforementioned tensile force. 
     However, random engraving of the connecting portion in order to lighten the same will considerably lower the rigidity of the connecting portion with respect to the aforementioned tensile force, and the connecting portion will be elastically deformed in the direction of the torque when acted on by the aforementioned tensile force. 
     SUMMARY OF THE INVENTION 
     In view of the aforementioned, an object of the present invention is to provide a webbing take-up device equipped with a frame which ensures sufficient rigidity and is light-weight. 
     A first aspect of the present invention is a webbing take-up device for taking-up and unwinding a webbing belt in a vehicle, the webbing belt having an end, wherein the belt is for fastening around a vehicle occupant, the device comprising a rotatably mounted take-up shaft adapted for receiving and anchoring an end of the webbing belt, and rotatably urged in a direction for taking-up the webbing belt and a frame having a pair of leg plates opposing each other between which the take-up shaft extends, a connecting portion integrally extending from one leg plate to the other, and a fixing portion adapted for fastening to the vehicle, the connecting portion having a plurality of apertures defined therein, at least some of the apertures formed as an elongated hole having a longitudinal axis formed substantially along a direction in which tensile force is applied via the take-up shaft and leg plates when the webbing belt is unwound. 
     In the webbing take-up device which is structured as described above, the take-up shaft, which is supported directly or indirectly by the leg plates of the frame, is urged in the direction in which the webbing belt, whose one end portion is engaged with the take-up shaft, is taken up. When a webbing belt which has been pulled out from the take-up shaft is applied to a vehicle occupant, the body of the vehicle occupant is restrained by the webbing belt which is urged by the urging force in the direction in which the webbing belt is taken up. 
     In the present webbing take-up device, because engraved portions formed by holes or thinned portions are formed in the connecting portion which connects the pair of leg plates, the connecting portion is lightened by the weight which has been removed by thinning or by the weight corresponding to the volume of the holes. 
     The engraved portions are formed along the direction in which tensile force acts on the connecting portion via the leg plates when the webbing belt which is taken up on the take-up shaft is pulled out, in the state in which the fixing portion of the connecting portion is fixed to the vehicle body. Furthermore, there are a plurality of engraved portions and these engraved portions are formed parallel to each other along the direction in which the tensile force acts. Therefore, between the engraved portions, there are formed portions that are not thinned portions or holes, whose longitudinal direction is along the direction in which the tensile force acts and whose widths are constant. As a result, the elasticity of the connecting portion against the tensile force is made uniform as compared to a case in which the engraved portions are randomly formed in the connecting portion. 
     The webbing take-up device of the present invention preferably includes the engraved portions formed continuously or intermittently along the direction from the fixing portion toward the pivotal portions which pivotably support the take-up shaft. 
     In the webbing take-up device which is structured as described above, the engraved portions are continuously or intermittently formed along the direction from the fixing portion of the connecting portion (that is, the portion at which the frame is fixed to the vehicle body), toward the supporting portion of the take-up shaft. In other words, the tensile force that acts on the take-up shaft when the webbing belt is pulled out acts on the support portions that pivotably support the take-up shaft. On the other hand, since the frame is fixed to the vehicle body at the fixing portion of the connecting portion, the connecting portion resists the tensile force at the fixing portion. Thus, the direction in which the tensile force acts on the connecting portion of the frame is the same as the direction from the fixing portion toward the supporting portion of the take-up shaft. The elasticity of the connecting portion with respect to the tensile force can be made even more uniform by forming the engraved portions continuously or intermittently along this direction, and by forming the regions between the engraved portions to have constant widths and such that the longitudinal directions thereof are along the direction of the tensile force. 
     The webbing take-up device of the present invention is preferably includes a locking device which locks prevents said take-up shaft from rotating in a direction for unwinding when the vehicle is in a state of rapid deceleration, the locking device including a connective part connecting said take-up shaft to at least one of said pair of leg plates in said state of rapid deceleration, wherein said elongated holes each have a longitudinal axis extending along a direction from said fixing portion toward said connective part. 
     In the webbing take-up device which is structured as described above, when the vehicle is in a state of rapid deceleration, the locking device connects the take-up shaft to at least one of the pair of leg plates so as to lock the take-up shaft. In this manner, the rotation of the take-up shaft in the pulling-out direction, which is opposite to the take-up direction, is restricted. When the vehicle is in a state of rapid deceleration, because the body of the vehicle occupant begins to move toward the front of the vehicle because of inertia, the webbing belt restraining the body of the vehicle occupant begins to be rapidly pulled out. At this time, the locking device locks the take-up shaft by connecting the take-up shaft to the leg plate and restricts the pulling-out of the webbing belt by restricting the rotation of the take-up shaft in the direction of pulling out. Thus, the force at the webbing belt for restraining the vehicle occupant is increased. 
     At this time, however, the excessive tensile force which pulls out the webbing belt when the body of the vehicle occupant begins to move toward the front of the vehicle due to inertia acts on the at least one leg plate that is connected to the take-up shaft by the locking device, and acts on the connecting portion via the leg plate or leg plates. 
     At this time, at least a portion of the tensile force acting on the connecting portion acts in a direction from the fixing portion of the connecting portion toward a connection portion of the leg plate connected to the take-up shaft via the locking device at the side connected to the take-up shaft by the locking device. 
     In the present webbing take-up device, the elasticity with respect to the excessive tensile force acting on the connecting portion while the vehicle is in a state of rapid deceleration is uniform because the engraved portions are formed continuously or intermittently along the direction described above, and because the intermediate portions between the engraved portions are formed such that their longitudinal directions are along the direction in which the tensile force acts and their widths are constant. 
     In the present invention, the direction in which the engraved portions are formed is parallel to a direction from the fixing portion toward the connection portion of the leg plate and the take-up shaft, at the side at which the leg plate is connected to the take-up shaft by the locking device. To clarify, the connection portion between the take-up shaft and the leg plate means, in a structure in which the take-up shaft and the leg plate are directly connected, the portion at which the take-up shaft and the leg plate are connected. However, if the take-up shaft and the leg plate are indirectly connected via a locking member which forms the locking device, the connection portion between the lock member and the take-up shaft is the connection portion between the take-up shaft and the leg plate. Furthermore, in the case where there is only one connection portion of the leg plate and the take-up shaft, the direction in which the engraved portions are formed is simply made parallel to the direction from the fixing portion toward the connection portion of the leg plate and the take-up shaft. In contrast, in the case where there are a plurality of connection portions and the directions from the fixing portion toward each of the connection portions are within a predetermined range of angles, the direction from the fixing portion toward the connection portion means the direction from the fixing portion toward the connection portion at which the tensile force actually acts when the tensile force acts on the leg plate. Furthermore, in the case where the tensile force acts on a plurality of connection portions, the direction from the fixing portion toward the connection portion, for the present invention, means, for example, the direction from the fixing portion toward the center of gravity of a polygon obtained by joining these connection portions. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view schematically showing the structure of a webbing take-up device relating to an embodiment of the present invention. 
     FIG. 2A is a rear view of the connecting portion showing the structure of the engraved portions, and 
     FIG. 2B is a partial section of the connecting portion of FIG. 2A wherein the apertures forming an engraved portion have been replaced with thinned portions. 
     FIG. 3 is a longitudinal sectional view schematically showing the structure of the webbing take-up device relating to the embodiment of the present invention, showing the direction of torque which is generated when a tensile force is applied. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     (Overall Structure of Webbing Take-up Device  10 ) 
     FIG. 1 is an exploded perspective view schematically illustrating the structure of a webbing take-up device  10  relating to an embodiment of the present invention. 
     As illustrated in FIG. 1, the webbing take-up device  10  includes a frame  18  having a pair of leg plates  12  and  14  which oppose each other along the direction of thickness of the plates, and a connecting portion  16  by which the leg plates  12  and  14  are connected at ones of transverse direction ends thereof. The frame  18  is formed in a substantial U-shape when viewed in plan view. The frame is provided with a spool  20  as a take-up shaft whose axial direction is along the transverse direction of the connecting portion  16 . The ends of the spool  20  penetrate the leg plates  12  and  14  to protrude outside the frame  18 . 
     One end portion of a webbing belt  22  for restraining a vehicle occupant, which is formed in an elongated belt shape, is anchored to the spool  20  at the axial direction central portion thereof, between the leg plates  12  and  14 . Due to the rotation of the spool  20  in one direction about the axis thereof, the webbing belt  22  is taken up. 
     A disc-shaped flange portion  26  is formed coaxially with and integrally with the spool  20  near one longitudinal direction end portion of the spool  20 . Furthermore, a pair of engaging portions  36  opposing each other across the spool  20  are formed at one end portion of the flange portion  26  in the axial direction thereof. Ratchet teeth are formed at portions of outer peripheries of the engaging portions  36 . Lock plates  38  are fitted with play on the ratchet teeth of the engaging portions  36 . The lock plates  38 , together with a ratchet hole  42  and a V-gear  46  which will be described later, form a locking means. 
     These lock plates  38  oppose, along the radial direction of the rotation of the spool  20 , the internal peripheral portion of the ratchet hole  42  which is formed in the leg plate  12 . Ratchet teeth are formed at the internal peripheral portion of the ratchet hole  42  and are able to mesh with the ratchet teeth formed at the external peripheral portions of the lock plates  38 . The lock plates  38  are usually disposed such that the external peripheral portions thereof are separated from the internal peripheral portion of the ratchet hole  42 . When the lock plates  38  move so as to approach the internal peripheral portion of the ratchet hole  42  and the ratchet teeth of the external peripheral portions mesh with the ratchet teeth of the internal peripheral portion of the ratchet hole  42 , the rotation of the lock plates  38 , with the rotational center of the spool  20  as an axis of rotation, in the direction of pulling out the webbing belt  22  is limited. 
     As shown in FIG. 1, the V-gear  46  is coaxially supported at one end portion of the spool  20 . A boss  48  of the V-gear  46  and the spool  20  are connected by a torsion coil spring  44 , which is attached by an unillustrated resin part such as a cap with a pawl, and the V-gear  46  normally rotates when the spool  20  rotates. Around the boss  48  of the V-gear  46 , there are formed four guide holes  50  and apertures  52  into which the engaging portions  36  of the spool  20  are inserted for free movement. A pair of projections  54  standing erect from each lock plate  38  are respectively inserted in these guide holes  50 . 
     At the outer circumference of the V-gear  46 , there are formed lock gear teeth  56  which restrict the rotation of the V-gear  46  when the lock gear teeth  54  are engaged with an unillustrated engaging pawl of an acceleration sensor which is provided at the radial direction outer side of the V-gear  46 . 
     The V-gear  46  and the acceleration sensor are accommodated within a cover  60  provided at the side of the leg plate  12 . One end portion of the spool  20  in the axial direction thereof is rotatably supported at a bearing portion (not shown) formed at the internal bottom portion of the cover  60 . 
     The cover  60  is made substantially integral with the leg plate  12  by a fastening means such as a screw or a bolt, or by a fitting means like pawls or projections formed on at least one of the leg plate  12  and the cover  60  such that the pawls or the projections are able to fit with the other of the leg plate  12  and the cover  60 , or by a joining means such as a fixing means such as an adhesive. 
     Also, as shown in FIG. 1, a spiral coil spring  64  is provided at the other end of the aforementioned spool  20  (that is, opposite to the end at which the engaging portions  36  are formed). The inner end portion of the spiral coil spring  64  engages with the spool  20 , and the external end portion thereof is fixed to a cover  68  provided at the side of the leg plate  14 . The spiral coil spring  64  urges the spool  20  in the take-up direction, at least when the webbing belt  22  is pulled out from the spool  20 . 
     The cover  68  is made substantially integral with the leg plate  14  by a fastening means such as a screw or a bolt, or by a fitting means like pawls or projections formed on at least one of the leg plate  14  and the cover  68  such that the pawls or the projections are able to fit with the other of the leg plate  14  and the cover  68 , or by a joining means such as a fixing means such as an adhesive. 
     (Structure of the Connecting Portion  16  of the Frame  18 ) 
     The webbing take-up device  10  of the structure described above is attached to a predetermined position, such as near the lower end portion (not shown) of a center pillar of a vehicle. The front view of the frame  18  is shown in FIG.  2 A. As shown in FIG. 2A, a portion of the connecting portion  16  of the frame  18 , below the connective parts at which the connecting portion  16  connects the leg plates  12  and  14 , is a substantially triangular fixing portion  70  whose width gradually becomes smaller downwardly. A bolt insertion hole  72  is formed in the vicinity of the peak portion (the lower end portion in FIG. 2A) of the fixing portion  70 , and penetrates through the connecting portion  16  in the direction of thickness thereof. The bolt insertion hole  72  is an elongated hole whose longitudinal direction is along the transverse direction of the connecting portion  16 . A bolt penetrates the bolt insertion hole  72  and penetrates a penetrating hole  30  of a supporting portion  28 , which is provided at a vehicle body, and is fastened by means of a nut or the like. Thus, the connecting portion  16  is fixed to the supporting portion  28  such that the webbing take-up device  10  is supported at the vehicle body. 
     A pair of positioning holes  74  are formed above the insertion hole  72 . Each of the positioning holes  74  is an elongated hole whose longitudinal direction is inclined toward the transverse direction from the longitudinal direction (vertical direction) of the connecting portion  16 . The positioning holes  74  are formed approximately along the transverse direction ends of the fixing portion  70 , and are disposed so as to be inclined obliquely downward in FIG. 2A, such that these positioning holes  74  approach each other toward the peak portion (lower end portion in FIG. 2A) of the fixing portion  70 . A pair of pawl portions  32  corresponding to these positioning holes  74  are formed at the supporting portion  28 , and the connecting portion  16  is provisionally supported at the supporting portion  28  by fitting these pawl portions  32  in the positioning holes  74 . In this way, the connecting portion  16  can be positioned with respect to the supporting portion  28 . 
     These positioning holes  74  can prevent the webbing take-up device  10  for the driver&#39;s seat and the webbing take-up device  10  for the front passenger&#39;s seat from being assembled at the respective wrong sides of the vehicle, by making the angle between the positioning holes  74  of the webbing take-up device  10  for the driver&#39;s seat and the angle between the positioning holes  74  of the webbing take-up device  10  for the front passenger&#39;s seat different from each other, and forming the pawls  32  such that the angle between the pawls  32  on the supporting portion  28  for the driver&#39;s seat and the angle between the pawls  32  on the supporting portion  28  for the front passenger&#39;s seat each match the angle between the corresponding pair of positioning holes  74 . 
     A pilot hole  76 , for guiding during a press molding process to form the frame  18 , is formed in the vicinity of the top end portion of the connecting portion  16 , at the transverse direction central portion thereof. A connector mounting hole  78  is provided below the pilot hole  76 . A connector, which is attached to a wire harness trailed close to the present webbing take-up device  10 , is fitted in the connector mounting hole  78 . Insertion hole  72 , pilot hole  76  and mounting hole  78  are all symmetrically aligned along an axis A as shown. 
     A plurality of engraved portions  80  and  82  are formed at the side of the connector mounting hole  78  toward the leg plate  12 . The engraved portion  80  is an elongated hole in which one end portion  80 A, which is disposed at the connecting portion  16  transverse direction central portion side of the engraved portion  80 , is located lower than another end portion  80 B, which is disposed at the connecting portion  16  transverse direction external portion side (that is, the direction toward the leg portion  12 ) of the engraved portion  80 . The longitudinal direction of the engraved portion  80  is along the direction from the end portion  80 A toward the end portion  80 B and the direction opposite thereto. The direction from the end portion  80 A toward the end portion  80 B is parallel to the direction from the center of the bolt insertion hole  72  toward the center of the ratchet hole  42  formed at the leg plate  12 . 
     The width dimension of the engraved portion  80  is approximately constant along the longitudinal direction thereof. An end portion  80 C and an end portion  80 D in the transverse direction of the engraved portion  80  are parallel to each other. However, the end portions  80 A and  80 B are substantially linear along the vertical direction of the connecting portion  16 , and thus are not perpendicular to the longitudinal direction of the engraved portion  80 . Therefore, the engraved portion  80  is formed overall as a substantially parallelogram shape. 
     The other engraved portion  82  is formed below the engraved portion  80 . The engraved portion  82  is formed by two through-holes, a substantially rectangular hole  84  and a substantially rectangular hole  86 . The substantially rectangular hole  84  is an elongated hole in which one end portion  84 A, which is disposed at the connecting portion  16  transverse direction central portion side of the substantially rectangular hole  84 , is located lower than another end portion  84 B, which is disposed at the connecting portion  16  transverse direction outer side (that is, the direction toward the leg plate  12 ) of the substantially rectangular hole  84 . The longitudinal direction of the substantially rectangular hole  84  is along the direction from the end portion  84 A toward the end portion  84 B or the direction opposite thereto. The width dimension of the substantially rectangular hole  84  is approximately constant along the longitudinal direction thereof, and the end portions  84 C and  84 D in the transverse direction of the substantially rectangular hole  84  are parallel to each other. However, the end portions  84 A and  84 B are substantially linear along the vertical direction of the connecting portion  16 , and thus are not perpendicular to the longitudinal direction of the substantially rectangular hole  84 . Therefore, the rectangular portion  84  is formed overall as a substantially parallelogram shape. 
     A substantially rectangular hole  86  is formed above the substantially rectangular hole  84  and toward the leg plate  12 . The substantially rectangular hole  86  is an elongated hole in which one end portion  86 B in the longitudinal direction of the connecting portion  16  is disposed at the connecting portion  16  transverse direction outer side of and above another end portion  86 A. The longitudinal direction of the substantially rectangular hole  86  is along the direction from the end portion  86 A toward the end portion  86 B or the direction opposite thereto. 
     Transverse direction end portions  86 C and  86 D of the substantially rectangular hole  86  are parallel to each other. The end portion  86 C is located along a line extended from the end portion  84 C of the aforementioned substantially rectangular hole  84 , and the end portion  86 D is located along a line extended from the end portion  84 D of the aforementioned substantially rectangular hole  84 . 
     A bridge portion  88  is formed between the end portion  86 A of the hole  86 , which end portion is at the connecting portion  16  transverse direction inner side of the hole  86 , and the end portion  84 B of the hole  84 , which end portion is at the connecting portion  16  transverse direction outer side (that is, toward the leg plate  12 ) of the hole  84 . The bridge portion  88  corresponds to the one of the pair of positioning holes  74  described above that is located comparatively toward the leg plate  12 . The bridge portion  88  is disposed above the one end portion of the two longitudinal direction end portions of the positioning hole  74  that is located toward the transverse direction outer side of the connecting portion  16 . Since the bridge portion  88  is disposed above the end portion located toward the transverse direction outer side of the connecting portion  16 , out of the projections formed at the supporting portion  28 , which is inserted in the positioning hole  74  for the purpose of positioning the frame  18 , is prevented from being incorrectly inserted in the substantially rectangular hole  84  or the substantially rectangular hole  86 . 
     The engraved portion  82 , formed by the substantially rectangular hole  84  and the substantially rectangular hole  86 , can be considered as being the substantially rectangular hole  84  and the substantially rectangular hole  86  divided by the bridge portion  88 . However, when the engraved portion  82  regarded from a functional point of view, it is better to consider it as being the engraved portion  82  divided by the bridge portion  88 . That is, if the bridge portion  88  were not formed in the engraved portion  82  shown in FIG. 2, the engraved portion  82  would be an elongated hole parallel to the engraved portion  80  along the direction from the end portion  84 A toward the end portion  86 B or the direction opposite thereto, whose longitudinal direction would be parallel to the direction from the center of the bolt insertion hole  72  toward the center of the ratchet hole  42  which is formed at the leg plate  12 . 
     As will be described in detail later, it is preferable that the longitudinal direction of the engraved portion  82  is along the direction in which the tensile force that acts on the connecting portion  16  acts. Therefore, the engraved portion  82  can be formed as a single substantially parallelogram shaped hole without providing the bridge portion  88 . 
     A plurality of engraved portions  90  and  92  are formed at the side of the pilot hole  76  toward the leg plate  14 . The engraved portion  90  is an elongated hole in which one end portion  90 A, which is disposed at the connecting portion  16  transverse direction central portion side of the engraved portion  90 , is located lower than another end portion  90 B, which is disposed at the connecting portion  16  transverse direction outer side (that is, the direction toward the leg portion  14 ) of the engraved portion  90 . The longitudinal direction of the engraved portion  90  is along the direction from the end portion  90 A toward the end portion  90 B or the direction opposite thereto. The direction from the end portion  90 A toward the end portion  90 B is parallel to the direction from the center of the bolt insertion hole  72  toward the center of the leg plate  14 . The width dimension of the engraved portion  90  is approximately constant along the longitudinal direction thereof. The end portions  90 C and  90 D of the engraved portion  90  in the transverse direction thereof are parallel to each other. However, the end portions  90 A and  90 B are substantially linear along the vertical direction of the connecting portion  16 , and thus are not perpendicular to the longitudinal direction of the engraved portion  90 . Therefore, the engraved portion  90  is formed overall as a substantially parallelogram shape. 
     The other engraved portion  92  is formed below the engraved portion  90 . The engraved portion  92  is formed by two through-holes, a substantially rectangular hole  94  and a substantially rectangular hole  96 . The substantially rectangular hole  94  is an elongated hole in which one end portion  94 A, which is disposed at the connecting portion  16  transverse direction central portion side of the substantially rectangular hole  94 , is located lower than another end portion  94 B, which is disposed at the connecting portion  16  transverse direction outer side (that is, the direction toward the leg plate  14 ) of the substantially rectangular hole  94 . The longitudinal direction of the substantially rectangular hole  94  is along the direction from the end portion  94 A toward the end portion  94 B or the direction opposite thereto. The width dimension of the substantially rectangular hole  94  is approximately constant along the longitudinal direction thereof, and the end portions  94 C and  94 D in the transverse direction of the substantially rectangular hole  94  are parallel to each other. However, the end portions  94 A and  94 B are substantially linear along the vertical direction of the connecting portion  16 , and thus are not perpendicular to the longitudinal direction of the substantially rectangular hole  94 . 
     The substantially rectangular hole  96  is formed above the substantially rectangular hole  94  and toward the leg plate  14 . The substantially rectangular hole  96  is an elongated hole with the longitudinal direction thereof being along the vertical direction of the connecting portion  16 . An upper end portion  96 B and a lower end portion  96 A are located along lines extended from the end portions  94 C and  94 D of the aforementioned substantially rectangular hole  94  respectively. On the other hand, the transverse direction end portions  96 C and  96 D of the substantially rectangular hole  96  are along the vertical direction of the connecting portion  16 , and are parallel to each other. That is, the substantially rectangular hole  96  is formed overall as a substantially parallelogram shape. 
     A bridge portion  98  is formed between the end portion  96 C of the hole  96 , which end portion is at the connecting portion  16  transverse direction inner side of the hole  96 ,and the end portion  94 B of the hole  94 , which end portion is at the connecting portion  16  transverse direction outer side (that is, toward the leg plate  14 ) of the hole  94 . The bridge portion  98  corresponds to the one of the pair of positioning holes  74  described above that is located comparatively toward the leg plate  14 . The bridge portion  98  is disposed above the one end portion of the two longitudinal direction end portions of the positioning hole  74  that is located toward the transverse direction outer side of the connecting portion  16 . Since the bridge portion  98  is disposed above the end portion located at the transverse direction outer side of the connecting portion  16 , one of the two pawl portions  32  of the supporting portion  28  is prevented from being incorrectly inserted in the substantially rectangular hole  94  or the substantially rectangular hole  96 . 
     The engraved portion  92 , formed by the substantially rectangular hole  94  and the substantially rectangular hole  96 , can be considered as being the substantially rectangular hole  94  and the substantially rectangular hole  96  divided by the bridge portion  98 . However, when the engraved portion  92  is regarded from a functional point of view, it is better to consider it as being the engraved portion  92  divided by the bridge portion  98 . 
     That is, if the bridge portion  98  were not formed in the engraved portion  92  shown in FIG. 2A, the engraved portion  92  would be a substantially parallelogram shaped hole parallel to the engraved portion  90  along the direction from the end portion  94 A toward the end portion  96 D or the direction opposite thereto, whose longitudinal direction would be parallel to the direction from the center of the bolt insertion hole  72  toward the center of the ratchet hole  42  which is formed at the leg plate  12 . 
     As is shown in FIG. 2B, the holes  80 ,  84 , and  86  forming the engraved portions  80  and  82  may also be formed from thinned portions  80 ′,  84 ′, and  86 ′ in the connecting portion  16  of the frame  18 . Although not specifically shown in FIG. 2B, the engraved portions  90  and  92  on the other side of the connecting portion  16  may also be formed from thinned portions in the frame  18 . The thinned portions may be made in the same shape as the illustrated holes. 
     As will be described in detail later, from the point of view of the first aspect of the present invention, it is preferable that the longitudinal direction of the engraved portion  92  is along the direction in which the tensile force that acts on the connecting portion  16  acts. Therefore, the engraved portion  92  can be formed as a single substantially parallelogram shaped hole, without providing the bridge portion  98 . 
     (Operation and Effects of the Present Embodiment) 
     The operation and effects of the present embodiment will be described hereinafter. 
     The present webbing take-up device  10  is attached to the predetermined position of a vehicle by fastening a bolt, which penetrates the bolt insertion hole  72  of the connecting portion  16  and then penetrates the supporting portion  28 , by means of a nut or the like. As described above, in the present webbing take-up device  10 , due to the formation of the engraved portions  80  and  82  (that is, the substantially rectangular hole  84  and the substantially rectangular hole  86 ) and  90  and  92  (that is, the substantially rectangular hole  94  and the substantially rectangular hole  96 ) , the weight of the connecting portion  16  is lightened by an amount corresponding to the volume of the engraved portions  80 ,  82 ,  90  and  92 , as compared to the case in which the connecting portion is formed without forming these engraved portions  80 ,  82 ,  90  and  92 . In this way, the weight of the frame  18  and thus the weight of the webbing take-up device  10  lightened, which enables, for example, improvement of specifications such as the fuel consumption of a vehicle. Further, the aforementioned engraved portions  80 ,  82 ,  90  and  92  can be formed easily by so-called punching during forming of the frame  18 , and moreover, during the punching process for punching the outline of the frame  18 . Thus, forming of the engraved portions will not cause an increase in the number of manufacturing processes and the cost. 
     In the present webbing take-up device  10  which has the effects described above, the vehicle occupant holds an unillustrated tongue plate through which the webbing belt  22  passes, pulls out the webbing belt  22 , and engages the tongue plate with an unillustrated buckle device, thereby applying the webbing of a three-point type seat belt device. That is, the portion of the webbing belt  22  between an unillustrated shoulder anchor provided at an upper portion of the center pillar and the tongue plate is the shoulder webbing, and the portion of the webbing belt  22  between the tongue plate and the webbing take-up device is the lap webbing. 
     At the time of a rapid deceleration of the vehicle while the webbing is applied to the vehicle occupant, the vehicle occupant&#39;s body begins to move toward the front of the vehicle due to inertia, and the webbing belt  22  begins to be pulled out. Due to the webbing belt  22  starting to be pulled out, the spool  20  begins to rotate in the direction in which the webbing is pulled out, and the V-gear  46  also begins to rotate along with the rotation of the spool  20 . The acceleration sensor which is provided at the radial direction outer side of the V-gear  46  detects the state of rapid deceleration of the vehicle, and limits the rotation of the V-gear  46  by engaging the engaging pawl with the V-gear  46 . As a result, the V-gear  46  rotates relative to the spool  20 , and each of the lock plates  38  is displaced outwardly along the radial direction of the spool  20 , while guided by the guide holes  50 . The displacement of each of the lock plates  38  causes the ratchet teeth of the lock plates  38  to mesh with the ratchet teeth formed at the ratchet hole  42  of the leg plate  12 . The rotation of the lock plates  38 , which rotate together with the spool  20 , is limited, and the rotation of the spool  20  in the direction in which the webbing belt  22  is pulled out is limited. Thus, pulling out of the webbing belt  22  is limited, and the restraining force by which the webbing belt restrains the body of the vehicle occupant increases. 
     When the body of the vehicle occupant begins to pull out the webbing belt  22  because of inertia at the time of a rapid deceleration of the vehicle, but the rotation of the spool  20  is limited, a tensile force F acts on the spool  20  via the webbing belt  22 , and then on the leg plate  12  via the lock plates  38  and on the leg plate  14  via the cover  68 , as shown in FIG.  3 . At the leg plate  12  side, the spool  20  pulls up the leg plate  12  with the ratchet hole  42  as the center. At the leg plate  14  side, because the spool  20  is connected to the leg plate  14  via the cover  68 , the cover  68  pulls up the leg plate  14  with the engaging portion of the cover  68  and the leg plate  14  as the center, or, if there are a plurality of engaging portions, with a portion corresponding to the center of gravity of a polygon formed by connecting the engaging portions as the center. Although the tensile force F thus acts on the leg portions  12  and  14 , since the connecting portion  16  is connected to the leg plates  12  and  14  at the transverse direction end portions thereof, when the tensile force F is applied, a torque M is generated in the direction of arrow A in FIG. 3, around the portion of the connecting portion  16  which is fixed to the supporting member  28  (that is, around the bolt insertion hole  72 ). 
     As described above, the leg plates  12  and  14  are connected to the connecting portion  16  at the transverse direction both end portions thereof. However, since the connecting portion  16  is fixed to the supporting portion  28  in the vicinity of the lower end portion of the transverse direction central portion of the connecting portion  16 , the tensile force F acts on the connecting portion  16  as shown in FIG.  3 . That is, the tensile force F acts along a direction from the substantial center of the bolt insertion hole  72 , at which the connecting portion  16  is fixed to the supporting portion  28 , toward the upper part of the connecting portion  16  and toward the transverse direction outer sides of the connecting portion  16 . In more detail, at the leg plate  12  side, the tensile force F acts along a direction from the substantial center of the bolt insertion hole  72  toward the positioning ratchet hole  42 , and at the leg plate  14  side, the tensile force F acts along a direction from the substantial center of the bolt insertion hole  72  toward the connection portion of the cover  68  with the leg plate  14 , or, if there are a plurality of connection portions, toward the center of gravity of a polygon formed by connecting the connection portions, or toward the central portion of the leg plate  14 . The tensile force F and the torque M caused by the tensile force F, which are described above, tend to deform the connecting plate  16 . 
     In the present webbing take-up device  10 , the formation of the engraved portions  80 ,  82 ,  90  and  92  in the connecting portion  16  as described earlier, inevitably lowers the overall rigidity of the connecting portion  16  relative to the case wherein the engraved portions  80 ,  82 ,  90  and  92  are not formed. 
     Consequently, the end portions  80 B and  90 B of the engraved portions  80  and  90 , which are disposed at the connecting portion  16  transverse direction outer sides of the engraved portions  80  and  90 , are located in a higher part of connecting portion  16  than the end portions  80 A and  90 A which are disposed at the connecting portion  16  transverse direction inner sides. That is, the longitudinal directions of the engraved portions  80  and  90  are along the directions in which the tensile force F acts on the connecting portion  16 . 
     Further, at the engraved portion  82  formed by the substantially rectangular holes  84  and  86 , the end portion  84 A, which is disposed at the connecting portion  16  transverse direction inner side of the substantially rectangular hole  84  that is disposed comparatively toward the transverse direction inner side of the connecting portion  16 , is lower than the end portion  86 B, which is disposed at the connecting portion  16  transverse direction outer side of the substantially rectangular hole  86  that is disposed comparatively toward the transverse direction outer side of the connecting portion  16 . Further, at the engraved portion  92  formed by the substantially rectangular holes  94  and  96 , the end portion  94 A, which is disposed at the connecting portion  16  transverse direction inner side of the substantially rectangular hole  94  that is disposed comparatively toward the transverse direction inner side of the connecting portion  16 , is lower than the end portion  96 D, which is disposed at the connecting portion  16  transverse direction outer side of the substantially rectangular hole  96  that is disposed comparatively toward the transverse direction outer side of the connecting portion  16 . Thus, the longitudinal direction of each of the engraved portions  82  and  92  is along the direction in which the tensile force F acts on the connecting portion  16 . 
     As a result, an intermediate portion  100  is formed between the engraved portion  80  and the engraved portion  82 . The longitudinal direction of intermediate portion  100  is along the direction in which the tensile force F acts on the connecting portion  16 , and the dimension of the space between the transverse direction end portions is generally equal along the longitudinal direction thereof. Also, an intermediate portion  102  is formed between the engraved portion  90  and the engraved portion  92 . The longitudinal direction of intermediate portion  102  is along the direction in which the tensile force F acts on the connecting portion  16 , and the dimension of the space between the transverse direction end portions is generally equal along the longitudinal direction thereof. 
     Although the overall stiffness of the connecting portion  16  is thus lowered, the formation of the intermediate portion  102 , whose longitudinal direction is along the direction in which the tensile force F acts on the connecting portion  16  and whose dimension of the space between the both transverse direction end portions is generally equal along the longitudinal direction thereof, ensures the strength (rigidity) of the connecting portion  16  against the tensile force F, and also makes the rigidity (or, the elasticity) of the connecting portion  16  against the tensile force F uniform. 
     Therefore, in the present webbing take-up device  10 , deformation of the connecting portion  16  due to the tensile force F and the torque M caused by the tensile force F can be suppressed or prevented, and resultantly, a reduction in the restraining force of the webbing belt  22  due to the deformation of the connecting portion  16  can be suppressed or prevented. 
     Although substantially rectangular holes  84 ,  86 ,  94  and  96  making up the engraved portions  82  and  92 , and the engraved portions  80  and  90 , are formed as substantially parallelogram shaped elongated holes in the present embodiment, engraved portions, in the broader meaning thereof are not limited to the elongated holes shown in the present embodiment. For example, the engraved portions can be a plurality of small holes, such as circular holes, formed in a plurality of lines along the direction of the tensile force F that acts on the connecting portion  16 , and the portions between these rows of small holes can be considered to be intermediate portions. Further, engraved portions, in the broader meaning thereof, need not always be holes penetrating the connecting portion  16  in the direction of thickness thereof, and may be portions at which the thickness of the connection portion  16  is reduced, as is shown in FIG.  2 B. 
     As described above, in the present invention, since the elasticity of the connecting portion along the direction in which the tensile force acts on the connecting portion of the frame when the webbing belt is pulled out is uniform, as compared to the case in which engraved portions are randomly formed at the connecting portion, the amount of elastic deformation of the connecting portion when the tensile force is applied can be made uniform, so the restraining force of the webbing belt can be ensured and maintained. Also, because the weight of the connecting portion can be reduced by the weight of the engraved portions, the weight of the whole device can be reduced.