Patent Publication Number: US-7712196-B2

Title: Belt lock

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a belt lock for locking a belt. Specifically, the invention relates to a belt lock including a base and an attachment to be detachably attached to the base, the attachment having a belt attaching section for attaching a belt. 
   2. Description of Related Art 
   As a belt lock for locking a belt, there has been known a buckle that can connect a plurality of belts to each other and separate the plurality of belts from each other. For example, as a buckle that can connect five seatbelts (a crotch belt, right and left waist belts, right and left shoulder belts) to each other and separate the five seatbelts from each other, a five-direction buckle has been known (see, for example, Document 1: JP-A-9-308508 and Document 2: U.S. Pat. No. 6,543,101). 
   The buckle includes: a socket; a pair of plugs to be disengageably inserted in the socket from openings on right and left sides of the socket; and attachments to be slidably attached to upper edges of the plugs. The socket includes a crotch belt attaching section for attaching the crotch belt. The plugs on the right and left sides each include a waist belt attaching hole for attaching the right or left waist belt. The attachments each include a shoulder belt attaching hole for respectively attaching the right and left shoulder belts. The plugs each include a rail with which a groove of the respective attachments is engaged. The rail has a stopper on an outer end of the rail. 
   In use, the attachments are firstly slid along the respective rails of the plugs to be attached to the plugs, and the plugs are inserted in the socket from the openings on the right and left sides of the socket to be engaged with the socket. Each of the attachments attached to the plugs is sandwiched by the stopper of the plug and a stopper of the socket, so that the attachments are prevented from dropping from the respective plugs. 
   Hence, even when tensile force is applied on the seatbelts (the crotch belt, the right and left waist belts, and the right and left shoulder belts), the plugs do not become disengaged from the socket and the attachments do not become disengaged from the plugs, so that the seatbelts are securely connected. 
   With the buckle having the above-described structure, when the plugs are inserted in and engaged with the socket, the attachments do not become disengaged owing to the stoppers of the plugs and the socket. However, when the plugs are disengaged from the socket, the attachments may become disengaged from the respective plugs. Specifically, when the plug is disengaged from the socket, the attachment may become disengaged from the plug contrary to the intention of an operator since the stopper of the socket does not act on the attachment. 
   In a general use, disengaging the plugs from the socket enables the shoulder belts to slip off the shoulders of an infant, so that it is not necessary to disengage the attachments from the plugs. 
   However, if the attachment is disengaged from the plug when the plug is disengaged from the socket, an operation for engaging the plug and the socket becomes complicated, which is not preferable. Concretely, because it becomes necessary to do an additional operation of attaching the attachment to the plug before inserting the plug into the socket for re-engagement, the operation for engaging the plug and the socket becomes complicated. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a belt lock in which an attachable/detachable attachment does not become disengaged contrary to the intention of an operator. 
   A belt lock of an aspect of the invention includes: a base; and an attachment to be detachably attached to the base, the attachment having a belt attaching section for attaching a belt. One of the base and the attachment is provided with a rail. The other of the base and the attachment is provided with a groove to be slidably engaged with the rail. The rail is provided with a lock section. The groove is provided with a to-be-locked section to be engaged with the lock section. 
   According to the aspect of the invention, since the attachment is attachable to and detachable from the base, the belt attached to the belt attaching section of the attachment can also be connected to and separated form the base. When the attachment is attached to the base, the rail and the groove slide on each other to be engaged with each other and the lock section of the rail and the to-be-locked section of the groove are locked to each other, so that the attachment can be prevented from being disengaged from the base contrary to the intention of an operator, thereby providing good operability of the attachment and the base. 
   With the belt lock of the aspect of the invention, one of the lock section and the to-be-locked section may preferably be formed as a recess and the other of the lock section and the to-be-locked section may preferably be formed as a protrusion to be engaged with the recess. One of the recess and the protrusion may preferably have a V-shape slope along the sliding direction of the rail and the groove. 
   According to the aspect of the invention, since one of the lock section and the to-be-locked section is formed as the recess and the other is formed as the protrusion, the lock section and the to-be-locked section can be securely locked to each other with the simple arrangement. In addition, the inclinations like V are provided in one of or both of the recess and the protrusion along the sliding direction. Hence, when the groove is slid on and engaged with the rail for engagement, one of the inclinations of the V-shape facilitates the engagement. On the other hand, when the engagement between the rail and the groove is released, the other of the inclinations of the V-shape facilitates the disengagement. 
   With the belt lock of the aspect of the invention, the rail may preferably include: a root section continuously formed from one of the base and the attachment; and a tip end section formed on a tip end side of the root section. The tip end section may preferably have a width larger than that of the root section. A width of the groove on a depth side may preferably be larger than that on an open side. The lock section may preferably be formed as a recess on an outer surface on a tip end side of the rail. The to-be-locked section may preferably be formed as a protrusion to be engaged with the recess. 
   According to the aspect of the invention, since the rail is formed in the shape in which the width of the root section is larger than that of the tip end section and the groove is formed in the shape in which the width thereof on the open side is larger than that on the depth side, thereby providing a structure in which the rail and the groove will not be easily disengaged from each other except for in the sliding direction. Further, the recess (the lock section) is formed on the outer surface of the tip end section of the rail and the protrusion to be locked in the recess (the to-be-locked section) is formed in the groove, thereby enabling the rail and the groove to engage with each other without looseness therebetween. 
   With the belt lock according to the aspect of the invention, the to-be-locked section may preferably be provided on a connecting section connecting front and rear walls in a direction in which the attachment is slid. The to-be-locked section may preferably be disposed at a middle position between the front and rear walls in the sliding direction of the attachment. The connecting section may preferably be deformable in a direction in which the lock section and the to-be-locked section are engaged. 
   According to the aspect of the invention, since the to-be-locked section is disposed in the middle of the connecting section that connects the forward and backward side walls in the sliding direction of the attachment, the connecting section can be easily deformed. Hence, the lock section and the to-be-locked section can be locked with a relatively small force. Owing to the structure in which the connecting section is deformed in the direction in which the lock section and the to-be-locked section are locked to each other, it is not necessary to employ a mechanism for displacing the lock section and the to-be-locked section, thereby simplifying the structure. 
   With the belt lock of the aspect of the invention, a socket and a plug that is disengageable from the socket are provided as the base. The plug includes: a base section; and an engaging section that projects from the base section and is inserted in and engaged with the socket. The base section includes the rail. The rail is formed substantially in parallel to a direction in which the plug is inserted into the socket. The attachment includes the groove to be slidably engaged with the rail. 
   According to the aspect of the invention, the invention can be applied as a buckle having the socket and the plug, and the buckle can provide the above-described advantages. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a whole perspective view showing an embodiment of the invention; 
       FIG. 2  is a front view of a belt lock when seen from a front side of the belt lock according to the aforesaid embodiment; 
       FIG. 3  is an exploded perspective view of the belt lock according to the aforesaid embodiment; 
       FIG. 4  is a (partial) cross section taken along line IV-IV of  FIG. 2 ; 
       FIGS. 5A and 5B  are cross sections showing a plug and an attachment in engagement according to the aforesaid embodiment; 
       FIG. 6  is a cross section taken along line VI-VI of  FIG. 5B ; 
       FIG. 7  is a view showing the plug and the socket in engagement according to the aforesaid embodiment; 
       FIG. 8  is an exploded perspective view showing a modification of the invention; and 
       FIG. 9  is an exploded perspective view showing another modification of the invention. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S) 
   An embodiment of the present invention will be described below with reference to the attached drawings. 
     FIGS. 1 to 7  illustrate the embodiment of the invention.  FIG. 1  is a whole perspective view showing a belt lock of the invention which is applied to seatbelts of a baby buggy.  FIG. 2  is a front view of the belt lock.  FIG. 3  is an exploded perspective view of the belt lock.  FIG. 4  is a cross section of a socket and a plug in engagement.  FIGS. 5A and 5B  are cross sections of the plug and an attachment in engagement.  FIG. 6  is a cross section taken along line VI-VI in  FIG. 5B .  FIG. 7  is a partially enlarged view showing the plug and the socket in engagement. 
   As shown in  FIG. 1 , the seatbelts of the baby buggy includes a crotch belt  5 , a pair of waist belts  6  and a pair of shoulder belts  7 . The crotch belt  5  extends upward with a first end fixed to a seat  2  and a second end oriented upward. The pair of waist belts  6  extends forward with first ends fixed to a backrest  3  on left and right sides of the backrest  3  and with second ends oriented forward. The pair of shoulder belts  7  extends downward with first ends fixed to the bracket  3  on an upper side of the backrest  3  and second ends oriented downward. A belt lock  9  of the embodiment is provided at a position where the second ends of the belts  5 ,  6  and  7  intersect. Note that an upward direction of the belt lock  9  is defined as a direction toward the shoulder belts  7  side, while a downward direction of the belt lock  9  is defined as a direction toward the crotch belt  5  side in the following description. 
   As shown in  FIGS. 2 and 3 , the belt lock  9  of the embodiment includes: a socket  10  connected to the second end of the crotch belt  5 ; a pair of plugs (bases)  20  respectively connected to the second ends of the waist belts  6 , the plugs  20  detachably inserted in the socket  10  from openings on right and left sides of the socket  10 ; and attachments  30  respectively connected to the second ends of the shoulder belts  7 , the attachments slidably attached on upper edges of the plugs  20 . Note that these components (the socket  10 , the pair of plugs  20  and the pair of attachments  30 ) are made of resin and formed by injection molding. 
   The socket  10  has a flat cylindrical shape with an insertion hole  11  defining openings in right and left surfaces of the socket  10 . The socket  10  includes: a belt attachment hole  12  (a crotch belt attaching section) for attaching the crotch belt  5 , the belt attachment hole  12  provided in a lower edge of the socket  10  (the upper side in  FIG. 3 ); and a stopper  13  that extends in a brim-like manner, the stopper  13  provided in the middle of an upper edge of the socket  10 . In the insertion hole  11 , four to-be-engaged sections  14  are formed on an inner surface of a front wall  11 A (see  FIG. 4 ) so as to extend inward. In the middle portion of a rear wall  11 B, an elastic leg piece  15  is cut and folded so as to project inward from the rear wall  11 B, the elastic leg piece  15  being in parallel to a direction of the insertion hole  11 . An operating section  17  is integrally formed via a connecting section  16  on the elastic leg piece  15 . The operating section  17  has an elliptical shape and is exposed from an opening  18  formed in the middle of the front wall  11 A. 
   The plug  20  is provided with a base section  21  in a flat trapezoidal shape, a supporting section  22  substantially in a U-shape in plan view and a tongue piece  23 . The supporting section  22  and the tongue piece  23  are integrally formed to the base section  21  so as to extend from a first end of the base section  21 . The supporting section  22  and the tongue piece  23  are inserted in the insertion hole  11  of the socket  10 . Engaging sections  24  are integrally formed on upper and lower ends of a tip of the tongue piece  23 . The engaging sections  24  are engaged with the to-be-engaged sections  14  provided on the front wall  11 A inside the insertion hole  11 . The base section  21  is provided with a belt attaching hole  25  (a waist belt attaching section) for attaching the right or left waist belt  6 . A rail  26  is integrally formed on an upper edge of the base section  21 . 
   In this embodiment, the rail  26  is formed on the upper side of the base section  21  to which the right or the left waist belt  6  is attached. However, the rail  26  may be formed on the lower side of the base section  21 . The rail  26  is formed substantially in parallel to a direction in which the plug  20  is inserted into the socket  10  and includes: a root section  26 A that is thinner than the base section  21  and is continuously formed from the base section  21  with a step; and a tip end section  26 B formed on the tip end side of the root section  26 A. The rail  26  is formed in a T-shape in cross section in which a width of the root section  26 A is larger than that of the tip end section  26 B (the width in the horizontal direction in  FIG. 6 ). The rail  26  is formed so as to project from the base section  21  in the direction in which the plug  20  is inserted. Specifically, the rail  26  is provided with an extension  28  extending so as to project from the base section  21 . Substantially in the middle of an outer surface of the tip end section  26 B, a recess  27  (a lock section) is provided. The recess  27  is formed as a V-groove with a V-shape slope along a longitudinal direction (a sliding direction) of the rail  26 . 
   The attachment  30  includes a groove  31  engaged with the rail  26  in a slidable manner and a belt attaching hole  32  (a shoulder belt attaching section) for receiving the right or left shoulder belt  7 . The groove  31  is formed in a T-shape in cross section in which a width of the groove  31  on an open side (a side opposing the root section  26 A) is larger than that on a depth side (a side opposing the tip end section  26 B). The groove  31  extends from one end to a middle position of the attachment  30 , but does not reach the other end (In other words, the groove  31  does not reach the socket  10  side surface of the attachment  30 ). Thus, since the rail  26  and the groove  31  have the same shape in cross section, the rail  26  and the groove  31  can be engaged with each other by sliding on each other. 
   Provided between the groove  31  and the belt attaching hole  32  is a connecting section  33  that connects front and rear side walls in the sliding direction of the attachment  30 , the connecting section  33  being jointed only to the front and rear side walls and being elastically deformable. A protrusion  34  (a to-be-locked section) that is engaged with the recess  27  is provided in the middle of the connecting section  33 , that is, in the middle of the front and rear walls in the sliding direction. The connecting section  33  is elastically deformable in a direction in which the recess  27  and the protrusion  34  are engaged (the direction in which the recess  27  is recessed and the protrusion  34  is projected). The protrusion  34  is formed so as to project in a V-shape having a V-shape slope along the longitudinal direction (the sliding direction) of the rail  26 . 
   Hence, lateral walls of the groove  31  which have different widths on the open side and the depth side form a space substantially in a T-shape together with the connecting section  33 , and the protrusion  34  (the to-be-locked section) of the connecting section  33  projects toward the open side of the groove  31 . 
   With the arrangements described above, the attachments  30  are attached to the respective plugs  20 . Specifically, the groove  31  of the attachment  30  is fitted in the rail  26  of the plug  20 , and the attachment  30  is slid in the direction from the tongue piece  23  side to the base section  21  side of the plug  20 . Accordingly, the connecting section  33  of the attachment  30  is elastically deformed toward the belt attaching hole  32  side, which is the upper side of the connecting section  33 , as shown in  FIG. 5A . As shown in  FIG. 5B , when the protrusion  34  of the attachment  30  reaches the recess  27  of the rail  26 , the protrusion  34  of the attachment  30  falls in (fits into) the recess  27  of the rail  26  and the connecting section  33  returns to its original shape. Thus, the attachment  30  is attached and locked to the plug  20 . 
   In this state, the waist belt  6  attached through the belt attaching hole  25  of the plug  20  and the shoulder belt  7  attached through the belt attaching hole  32  of the attachment  30  are substantially orthogonal to each other. Hence, even when the belts  6 ,  7  are pulled in the orthogonal directions, the attachment  30  does not become disengaged in the direction in which the attachment is pulled owing to the tip end section  26 B of the rail  26 . 
   The plug  20  is then inserted in the socket  10  with the attachment  30  attached to the plug  20 . As shown in  FIG. 2 , when the plug  20  is inserted in the plug  30 , an inner end of the attachment  30  abuts to the stopper  13  of the socket  10 , so that the attachment  30  does not become disengaged from the socket  10 . 
   More specifically, as shown in  FIG. 7 , when the plug  20  is inserted in and engaged with the socket  10 , the extension  28  of the rail  26  is on an upper edge of the socket  10 . Accordingly, a space between the stopper  13  and the extension  28  is small, so that the attachment  30  is prevented from easily becoming disengaged. Note that since the extension  28  of the rail  26  projects from the base section  21  in the insertion direction of the plug  20 , the groove  31  of the attachment  30  can be easily fit in the rail  26  when the attachment  30  is fit into the rail  26 . 
   When the plug  20  is inserted in the socket  10 , the engaging sections  24  of the tongue piece  23  of the plug  20  are engaged with the to-be-engaged sections  14  inside the socket  10 , so that the plug  20  is engaged with the socket  10 . 
   To disengage the plug  20  from the socket  10 , the operation section  17  is pressed toward the rear wall  11 B. This pressing makes the tongue piece  23  be deformed toward the rear wall  11 B in the insertion hole  11 , so that the engaging sections  24  are disengaged from the to-be-engaged sections  14 , thereby releasing the engagement. The plug  20  is thus disengaged from the socket  10 . 
   When the plugs  20  are disengaged from the socket  10 , the waist belts  6  and the shoulder belts  7  are opened in horizontal directions, so that a baby can be taken out of the baby buggy. As explained above, although the attachment  30  is capable of being disengaged from the plug  20 , it is not necessary to disengage the attachment  30  from the plug  20  to free the baby from the baby buggy. 
   Conventional attachments have a structure in which the attachment is inserted in the plug in a sliding manner. Hence, when the plug is disengaged from the socket, the attachment may also be disengaged from the plug contrary to the intention of the operator. In this case, it is necessary to attach the attachment to the plug before inserting the plug again in the socket for re-engagement, complicating the operation for engagement of the plug and the socket. 
   In contrast, according to the belt lock  9  of the embodiment of the invention, the attachment  30  and the plug  20  are locked by the recess  27  and the protrusion  34 , so that the attachment  30  can be prevented from becoming disengaged from the plug  20  contrary to the intention of the operator, thereby providing good operability of the plug  20  and the socket  10 . 
   Thus, the above-described embodiment can provide following advantages.
     (1) When the attachment  30  is attached to the plug  20 , the rail  26  and the groove  31  slide on each other to be engaged with each other and the recess  27  of the rail  26  and the protrusion  34  of the attachment  30  are engaged with each other, so that the attachment  30  can be prevented from becoming disengaged from the plug  20  contrary to the intention of the operator. Accordingly, good operability of the plug  20  and the socket  10  can be provided.   (2) The plug  20  and the attachment  30  are locked through the engagement between the recess  27  and the protrusion  34 . Hence, the plug  20  and the attachment  30  can be securely locked with a simple arrangement. In addition, the V-shape slope is provided in both of the recess  27  and the protrusion  34  along the sliding direction. Hence, when the groove  31  is slid on and engaged with the rail  26 , the protrusion  34  can smoothly move onto an upper surface of the rail  26  owing to a half of the V-shape slope, thereby facilitating a smooth engagement. On the other hand, when the engagement between the rail  26  and the groove  31  is released, the other half of the V-shape slope facilitates the release of the engagement.   (3) Since the connecting section  33  of the attachment  30  is elastically deformed for the engagement of the protrusion  34  into the recess  27  when attaching the attachment  30  to the plug  20 , the attachment  30  can be easily attached to the plug  20  with a relatively small force. Owing to the structure in which the connecting section  33  can be elastically deformed, it is not necessary to employ a mechanism for displacing the recess  27  and the protrusion  34 , thereby simplifying the structure.   (4) The rail  26  is formed in the shape in which the width of the root section  26 A is larger than that of the tip end section  26 B and the groove  31  is formed in the shape in which the width thereof on the open side is larger than that on the depth side, thereby providing a structure in which the rail  26  and the groove  31  do not easily become disengaged from each other except for in the sliding direction. Further, the recess  27  is formed in the outer surface of the tip end section  26 B of the rail  26  and the protrusion  34  to be engaged in the recess  27  is provided on the attachment  30 , thereby enabling the rail  26  and the groove  31  to engage with each other without looseness therebetween.   (5) Since the protrusion  34  is disposed in the middle of the connecting section  33  that connects the front and rear walls in the sliding direction of the attachment  30 , the connecting section  33  can be easily deformed. Hence, the recess  27  and the protrusion  34  can be engaged with a relatively small force.
 
[Modifications]
   

   The scope of the present invention is not restricted to the above-described embodiment, but includes modifications and improvements as long as an object of the invention can be achieved. 
   For example, the lock mechanism of the plug  20  and the attachment  30  is not limited to that of the above-described embodiment, but may be the one shown in  FIGS. 8 and 9 . 
     FIG. 8  shows the plug  20  and the attachment  30  which are used for the belt lock  9  shown in  FIG. 1 . The lock section  27 A of this exemplary modification is provided to the rail  26  of the plug  20 , which is the same as the above-described embodiment. However, the lock section  27 A of the modification is formed in a hemisphere shape projecting toward the front side of the plug  20 . The to-be-locked section  34 A is provided to the attachment  30 , which is the same as the above-described embodiment. However, the to-be-locked section  34 A of the modification is formed as a hole penetrating in a cylindrical shape. 
   Note that the lock section  27 A in the hemisphere shape may be provided on both sides of the rail  26 . In this case, the to-be-locked section  34 A needs to be provided on both sides of the groove  31  of the attachment  30  in accordance with the lock sections  27 A. 
     FIG. 9  shows a belt lock  9 A including a base  40  and the attachment  30 . 
   The base  40  is formed in a rectangular frame shape. A connecting bar  43  connecting lateral sides  41 ,  42  defines two belt insertion holes  44 . On the lateral side  41  side, the groove  31  and the connecting section  33  are formed. The connecting section  33  is provided with the protrusion (the to-be-locked section)  34  and a space for allowing an elastic deformation thereof on the other side of the groove  31  of the connecting section  33 . 
   The attachment  30  of the modification is not provided with the groove  31  and the connecting section  33  having the to-be-locked section (the protrusion)  34  which are provided to the attachment in the above-described embodiment. Alternatively, the attachment  30  of the modification is provided with the integrally-formed rail  26  having the recess (the lock section)  27 . 
   As thus far described, although the plug  20  is provided with the rail  26  and the attachment  30  is provided with the groove  31  in the above-described embodiment, the plug  20  and the attachment  30  may be provided vice versa. Specifically, the plug  20  may be provided with the groove  31 , and the attachment  30  may be provided with the rail  26 . 
   In the above-described embodiment, the rail  26  of the plug  20  is provided with the lock section (the recess)  27  and the attachment  30  is provided with the to-be-locked section (the protrusion)  34 . However, in the arrangement in which the plug  20  is provided with the groove  31  and the attachment  30  is provided with the rail  26 , the rail  26  of the attachment  30  may be provided with the lock section (the recess)  27 , and the plug  20  may be provided with the to-be-locked section (the protrusion)  34 . In other words, it is only necessary that the lock section is provided to the rail  26  and the to-be-locked section is provided to a component provided with the groove  31 . 
   In the above-described embodiment, the lock section is the recess  27  and the to-be-locked section is the protrusion  34 . However, the lock section and the to-be-locked section may be vice versa, which means the lock section may be the protrusion  34  and the to-be-locked section may be the recess  27 . 
   Both of the lock section and the to-be-locked section are formed in the V-groove and the V-projection which have the V-shape slope along the sliding direction. However, only one of the lock section and the to-be-locked section may be the V-groove or the V-projection. In addition, the shape of the lock section and the to-be-locked section may not be the V-groove and the V-projection but any shape as long as the lock section and the to-be-locked section can be engaged to each other. 
   In the above-described embodiment, the elastically deformable connecting section  33  of the attachment is provided with the to-be-locked section (the protrusion)  34 , but may be provided with the lock section (the recess)  27 . 
   In the above-described embodiment, the rail  26  and the groove  31  have the T-shape in cross section. However, the shapes thereof are not limited thereto, but may be any as long as the rail  26  and the groove  31  do not easily become disengaged from each other. For example, arranging the rail and the groove in a converted trapezoidal shape can provide advantages similar to the above-described embodiment. 
   The priority application Number JP2005-224514 upon which this patent application is based is hereby incorporated by reference.