Abstract:
Provided is a waterproof structure capable of facilitating positioning of a packing. A waterproof structure according to one aspect of the present invention includes a first case having a groove formed therein, a packing that is disposed in the groove, a second case that pushes the packing and forms a sealed space with the first case. The packing includes a bending part, and the groove includes a guiding part that guides a tip of the bending part to a predetermined position on the bottom surface of the groove in the first case.

Description:
TECHNICAL FIELD 
     The present invention relates to a waterproof structure and a method of forming the same, and particularly to a waterproof structure used to form a sealed space by a first case and a second case and a method of forming the same. 
     BACKGROUND ART 
     When a sealed space is formed by a first case and a second case, it is common to dispose a packing  3  between a first case  1  and a second case  2 , as shown in  FIG. 1  That is, the packing  3  is disposed in a groove  11  formed in the first case  1 . Then, the first case  1  and the second case  2  are bonded by bolts  4  with the packing  32  interposed therebetween. 
     In such a case, as shown in  FIG. 11 , the packing  3  is pushed by a protrusion  21  that is formed to the second case  2 . Note that  FIG. 11  illustrates the packing  3  in a state not pushed by the protrusion  21  of the second case  2 . Therefore, the dashed line of  FIG. 11  is a virtual line of the protrusion  21 . 
     A large reaction force generated in the packing  3  when the packing  3  is compressed, as mentioned above, could raise the second case  2 . For this reason, the packing  3  is devised to include a protrusion  31  formed thereto, so that when the packing  3  is pushed by the protrusion  21  of the second case  2 , the protrusion  31  will not deform and generate a large reaction force as shown in  FIG. 12 . 
     However, even when the protrusion  31  is formed to the packing  3 , a large reaction force is still generated in the packing  3 . Therefore, as shown in  FIGS. 11 and 12 , a pawl  12  is formed to the first case  1 , for example. A pawl  25  is formed also to the second case  2 . Then, the pawl  12  of the first case  1  and the pawl  25  of the second case  2  are engaged to counter the reaction force and prevent the second case  2  from rising. Such a configuration causes an increase in the size of the cases due to the pawls formed to the both cases. 
     Incidentally, patent literature 1 discloses a technique of forming a sealed space by a first case and a second case using a gasket including protrusions on both upper and lower ends with their cross-sectional shapes protruding in the same direction and a middle protrusion on a substantially central part protruding in the same direction as the protrusions. 
     Moreover, patent literature 2 discloses a technique of forming a sealed space by a first case and a second case using a gasket including a lip part extending obliquely upward from a body with its cross-sectional shape being substantially elliptical. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent literature 1: Japanese Unexamined Patent Application Publication No. H10-154750 
         Patent literature 2: Japanese Unexamined Patent Application Publication No. 2006-220229 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     The techniques disclosed in patent literatures 1 and 2 are unable to easily determine a position of the gasket when the gasket disposed in a groove in the first case is pushed by the second case. Accordingly, a push by the second case may bend the protrusion and lip part in an unintended direction. 
     An objective of the present invention is to provide a waterproof structure to solve the abovementioned issue and a method of forming the same. 
     Solution to Problem 
     In an exemplary aspect of the present invention, a waterproof structure includes a first case having a groove formed therein, a packing that is disposed in the groove, and a second case that pushes the packing and forms a sealed space with the first case. The packing includes a bending part, and while the packing is not pushed by the second case, a contact point is disposed offset toward a bending direction of the bending part from a straight line, in which the contact point is between a tip of the bending part and a bottom surface of the groove in the first case, and the straight line passes through a bending point of the bending part and is substantially orthogonal to a contact surface of the second case to be in contact with the packing, and the groove includes a guiding part that guides the tip of the bending part to a predetermined position on the bottom surface of the groove in the first case. 
     In another exemplary aspect of the present invention, a method of forming a waterproof structure includes disposing a packing in a groove formed in a first case, guiding, by a guiding part of the first case, a tip of a bending part of the packing to a predetermined position on a bottom surface of the groove in the first case, and disposing a contact point offset toward a bending direction of the bending part from a straight line, in which the contact point is between the tip of the bending part of the packing and the bottom surface of the groove in the first case, and the straight line passes through a bending point of the bending part and is substantially orthogonal to a contact surface of the second case to be in contact with the packing, and pushing the packing by the second case, and forming a sealed space with the first case. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to provide the waterproof structure that facilitates positioning of the packing and the method of forming the same. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a structural drawing schematically showing a common waterproof structure; 
         FIG. 2  is a cross-sectional diagram showing a state before a second case pushes a packing in a waterproof structure according to a first exemplary embodiment of the present invention; 
         FIG. 3  is a cross-sectional diagram showing a state after the second case pushes the packing in the waterproof structure according to the first exemplary embodiment of the present invention; 
         FIG. 4  is a cross-sectional diagram showing a state before a second case pushes a packing in a waterproof structure according to a second exemplary embodiment of the present invention; 
         FIG. 5  is a cross-sectional diagram showing a state after the second case pushes the packing in the waterproof structure according to the second exemplary embodiment of the present invention; 
         FIG. 6  is a cross-sectional diagram showing a state before a second case pushes a packing in a waterproof structure according to a third exemplary embodiment of the present invention; 
         FIG. 7  is a cross-sectional diagram showing a state after a second case pushes a packing in a waterproof structure according to a fourth exemplary embodiment of the present invention; 
         FIG. 8  is a cross-sectional diagram showing a state before a second case pushes a packing in a different waterproof structure; 
         FIG. 9  is a cross-sectional diagram showing a state after the second case pushes the packing in the different waterproof structure; 
         FIG. 10  is a cross-sectional diagram showing a state after a second case pushes a packing in another different waterproof structure; 
         FIG. 11  is a cross-sectional diagram showing a related waterproof structure; and 
         FIG. 12  is a cross-sectional diagram showing the related waterproof structure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A waterproof structure according to exemplary embodiments of the present invention and a method of forming the same are explained. However, the present invention is not necessarily limited to the following exemplary embodiments. Moreover, following description and drawings are simplified as appropriate for clarity of the explanation. In addition, an up-and-down direction in the following explanation is based on the drawings and changes according to the usages. 
     [First Exemplary Embodiment] 
     A waterproof structure according to a first exemplary embodiment and a method of forming the same are explained. The waterproof structure and the method of forming the same according to this exemplary embodiment can be preferably used for a waterproof structure of electronic devices such as cell phones, smartphones, PDAs (Personal Digital Assistants), and tablet PCs (Personal Computers). 
     This waterproof structure has similar components as a common waterproof structure. Specifically, the waterproof structure includes a first case  1 , a second case  2 , and a packing  3 , as shown in  FIG. 1 . 
     The first case  1  has an opening in an upper surface (may be a lower surface). The first case  1  has a space  13  capable of mounting inside an electronic substrate, a display device and the like for realizing functions of the electronic devices, for example. A riser part  14  is formed to surround the space  13 . 
     An upper surface  15  of the riser part  14  is formed in a plane, as shown in  FIG. 2 . The riser part  14  has a sufficient width dimension to form a groove  11  for fitting the packing  3 . The groove  11  is formed in the riser part  14 . The groove  11  is formed annularly in planar view to surround an outer edge of the first case  1 . Note that the specific shape of the groove  11  is described later. Bolt holes  5  are formed in four corners of the first case  1  outward of the riser part  14 . 
     The second case  2  is a lid component that covers the opening of the first case  1  in order to form a sealed space with the first case  1 . As shown in  FIG. 2 , at least a region  22  is formed in a plane, which comes into contact with the upper surface  15  of the riser part  14  of the first case  1  when the second case  2  is disposed to cover the first case  1 . Therefore, as shown in  FIG. 3 , when the second case  2  covers the first case  1 , the upper surface  15  of the riser part  14  of the first case  1  and the region  22  of the second case  2  come into contact on their surfaces. 
     The second case  2  is formed in a planar shape that is substantially equivalent to the first case  1 . As shown in  FIG. 2 , a protrusion  21  that pushes the packing  3  is formed at a position corresponding to the groove  11  in the first case  1 . The protrusion  21  is also formed annularly in planar view. A lower surface  23  of the protrusion  21  is formed to be a substantially parallel surface to the region  22 . 
     The width dimension of the protrusion  21  is set to enable the protrusion  21  to be inserted into the groove  11  in the first case  1 . Moreover, although mentioned later for details, the height of the protrusion  21  is set to enable a bending part  32  to bend in a bending direction (direction indicated by an arrow Q (outward direction of the first case  1 )) of the bending part  32  of the packing  3  from the state of  FIG. 2  to the state of  FIG. 3 . 
     The packing  3  is disposed in the groove  11  in the first case  1 , as shown in  FIGS. 1 ,  2  and the like. That is, the packing  3  is formed annularly to conform to the shape of the groove  11  in the first case  1 . The packing  3  is a resin molding such as rubber with elasticity. As shown in  FIG. 2 , the packing  3  includes the bending part  32  and a base part  33 . 
     The base part  33  is formed to be a substantially rectangular shape when viewed in cross section. The bending part  32  protrudes from a lower end of the base part  33 . Specifically, the bending part  32  protrudes at a predetermined angle from a corner inward of the first case  1  on the lower end of the base part  33 . The thickness of the bending part  32  on a connection part with the base part  33  is set in such a manner that the bending part  32  rotates in the bending direction when pushed from above by the protrusion  21  of the second case  2 , and the bending part  32  extends obliquely downward with its thickness. That is, the bending part  32  protrudes in a tongue shape from the lower end of the base part  33 . 
     A tip of the bending part  32  is formed in a roundish shape to slide well on a guiding part  16  and a bottom surface  18  of the groove  11 , as described later. Note that a cutout  34  is formed in the lower end of the base part  33  so as not to hinder the bending part  32  from bending. 
     In regard to the packing  3  configured as above, as shown in  FIG. 2 , in the state where the packing  3  is disposed in the groove  11  and the packing  3  is not yet pushed by the protrusion  21  of the second case  2 , a contact point P, which is between the tip of the bending part  32  of the packing  3  and the bottom surface  1   8  of the groove  11  in the first case  1 , is disposed on a straight line N that passes through a bending point O (bottom part of constriction) of the bending part  32  and is substantially orthogonal to the lower surface  23  of the protrusion  21  of the second case  2 , or placed offset from the straight line N toward the bending direction of the bending part  32 . 
     The shape of the groove  11  in the first case  1  is explained here. The groove  11  is formed in a substantially rectangular shape when viewed in cross section, as shown in  FIG. 2 . As shown in  FIG. 3 , the width dimension of the groove  11  is set to allow the bending part  32  of the packing  3  to rotate well in the bending direction. Moreover, the depth of the groove  11  is set in such a manner that when the packing  3  disposed in the groove  11  is pushed by the protrusion  21  of the second case  2 , the base part  33  is not substantially compressed, the bending part  32  rotates in the bending direction, and the amount of push by the protrusion  21  is absorbed. A bottom part of this groove  11  includes the guiding part  16  that guides the tip of the bending part  32  of the packing  3  to a predetermined position. 
     The guiding part  16  is a sloping surface that continuously slopes downward from an inward surface  17  of the groove  11  to the bottom surface  18  of the groove  11 . As shown in  FIG. 2 , an intersection C between the guiding part  16  and the bottom surface  18  is set to a position in such a manner that when the packing  3  is disposed in the groove  11  in a state where the bending direction of the bending part  32  of the packing  3  faces outwardly of the first case  1 , and then a surface  35  (a surface of the base part  33  inward of the first case  1  in this exemplary embodiment), which is a surface of the base part  33  of the packing  3  opposite to the bending direction of the bending part  32 , comes into contact with the inward surface  17  of the groove  11 , the tip of the bending part  32  of the packing  3  comes into contact with the bottom surface  18  of the groove  11 . However, the intersection C may be offset outwardly or inwardly of the first case  1 , in short, the intersection C should only be capable of guiding the bending part  32  of the packing  3  to bend in the intended bending direction. An inclination angle of the guiding part  16  is set to allow the tip of the bending part  32  of the packing  3  to slide and be guided when the packing  3  is disposed in the groove  11 . 
     The first case  1 , the second case  2 , and the packing  3  configured in this way realize the waterproof structure as stated below. 
     As shown in  FIG. 2 , in the state where the bending direction of the bending part  32  of the packing  3  faces outwardly of the first case  1 , the packing  3  is disposed in the groove  11  in the first case  1 . At this time, the tip of the bending part  32  of the packing  3  slide on the guiding part  16  and is guided to the intersection C. Moreover, the surface  35  of the base part  33  of the packing  3  that is opposite to the bending direction of the bending part  32  comes into contact with the surface  17  of the groove  11  inward of the first case  1 . That is, the packing  3  is positioned in the state where the packing  3  leans on the surface  17  of the groove  11  inward of the first case  1 . 
     Although the protrusion  21  of the second case  2  pushes the packing  3  in this state, immediately before the push, the intersection C where the tip of the bending part  32  is located is placed on the straight line N, which passes through the bending point O of the bending part  32  and is substantially orthogonal to the lower surface  23  of the protrusion  21  of the second case  2 , or placed offset from the straight line N toward the bending direction of the bending part  32 . 
     The protrusion  21  of the second case  2  is disposed above the packing  3 . The protrusion  21  of the second case  2  pushes the packing  3 . Then, in the packing  3 , the base part  33  is hardly compressed, and the bending part  32  rotates in the bending direction and becomes the state shown in  FIG. 3 . At this time, the contact point P between the tip of the bending part  32  of the packing  3  and the bottom surface  18  of the groove  11  moves outwardly of the first case  1  while a surface  36  (a surface of the bending part  32  inward of the first case  1  in this exemplary embodiment), which is a surface of the bending part  32  opposite to the bending direction, comes into contact with the guiding part  16 . This therefore can stabilize the packing  3  in the groove part  11 . This further increases a contact area between the packing  3  and the groove  11 , thereby improving waterproof performance. 
     Lastly, bonding the first case  1  and the second case  2  by the bolts  4  realizes the waterproof structure. 
     In such a waterproof structure, the guiding part  16  can guide the tip of the bending part  32  of the packing  3  to the predetermined position (intersection C) on the bottom surface  18  of the groove  11 . This therefore facilitates positioning of the packing  3  in the groove  11 . Thus, when the protrusion  21  of the second case  2  pushes the packing  3 , the bending part  32  of the packing  3  will not rotate in an unintended direction. This prevents damage to the packing  3  and improves the productivity of electronic devices with excellent waterproof performance. 
     Further, as the rotation of the bending part  32  of the packing  3  absorbs the amount of push by the protrusion  21  of the second case  2 , a reaction force is hardly generated in the packing  3 . As it is almost unnecessary for the first case  1  and the second case  2  to counter the reaction force of the packing  3 , the size of the first case  1  and the second case  2  can be reduced and the first case  1  and the second case  2  can be simplified. 
     Incidentally, in the packing  3  of this exemplary embodiment, the bending direction of the bending part  32  faces outwardly of the first case  1 . That is, it is hard for the bending part  32  to rotate inwardly of the first case  1 . For this reason, in case of water ingress from outside the first case  1  into the groove  11 , the bending part  32  functions as a valve to prevent the water ingress. 
     [Second Exemplary Embodiment] 
     Although in the packing  3  of the first exemplary embodiment, the bending direction of the bending part  32  faces outwardly of the first case  1 , a substantially similar operation can be achieved when the bending direction of the bending part  32  faces inwardly of the first case  1 . 
     That is, as shown in  FIG. 4 , in the state where the bending direction of the bending part  32  of the packing  3  faces inwardly of the first case  1 , the packing  3  is disposed in the groove  11  in the first case  1 . Also in this case, the guiding part  16  of the groove  11  in the first case  1  is formed in such a manner that the tip of the bending part  32  of the packing  3  is disposed at a predetermined position on the bottom surface of the groove  11  when the packing  3  is disposed in the groove  11  in the first case  1 . 
     Specifically, the guiding part  16  is a sloping surface that continuously slopes downward from a surface  19 , which is a surface of the groove  11  outward of the first case  1 , to the bottom surface  18 . As shown in  FIG. 4 , the intersection C between the guiding part  16  and the bottom surface  18  is set to a position in such a manner that when the packing  3  is disposed in the groove  11  in a state where the bending part  32  of the packing  3  faces inwardly of the first case  1 , and then a surface  37  (a surface of the base part  33  inward of the first case  1  in this exemplary embodiment), which is a surface of the base part  33  of the packing  3  on the bending direction of the bending part  32 , comes into contact with the surface  17  of the groove  11  inward of the first case  1 , the tip of the bending part  32  of the packing  3  comes into contact with the bottom surface  18  of the groove  11 . However, the intersection C may be offset outwardly or inwardly of the first case  1 , in short, the intersection C should only be capable of guiding the bending part  32  of the packing  3  to bend in the intended bending direction. 
     Then, when the packing  3  is disposed in the groove  11  in the first case  1 , the guiding part  16  can guide the tip of the bending part  32  of the packing  3  to the predetermined position (intersection C) on the bottom surface  18  of the groove  11 . In a similar manner as the first exemplary embodiment, when the protrusion  21  of the second case  2  pushes the packing  3 , the base part  33  is hardly compressed, and the bending part  32  rotates in the bending direction (direction indicated by an arrow R) and becomes the state shown in  FIG. 5 . At this time, the contact point P between the tip of the bending part  32  of the packing  3  and the bottom surface  18  of the groove  11  moves inwardly of the first case  1  while the surface  36  (the surface of the bending part  32  outward of the first case  1  in this exemplary embodiment), which is the surface of the bending part  32  opposite to the bending direction, comes into contact with the guiding part  16 . Moreover, the surface  35  (the surface of the base part  33  outward of the first case  1  in this exemplary embodiment), which is the surface of the base part  33  of the packing  3  that is opposite to the bending direction of the bending part  32 , comes into contact with the surface  19  of the groove  11  outward of the first case I. 
     Incidentally, when the bending part  32  of the packing  3  is disposed facing inwardly of the first case  1 , the bending part  32  can easily rotate inwardly of the first case  1 . Therefore, in case of water ingress from outside the first case  1  into the groove  1 , the bending part  32  is pushed by the water and rotates in the bending direction, thereby resulting in allowing the water ingress inside the first case  1 . For this reason, it is preferable to reinforce the vicinity of the bending point O of the bending part  32  by padding  6  and the like. This enables prevention of the water ingress inside the first case  1 . 
     [Third Exemplary Embodiment] 
     Although the tip of the bending part  32  of the packing  3  according to the first and second exemplary embodiments is formed in a roundish shape, the tip of the bending part  32  may be formed sharply, as shown in  FIG. 6 . This reduces a contact area between the tip of the bending part  32  and the guiding part  16  and the bottom surface  18  of the groove  11 , thereby reducing friction when the tip of the bending part  32  slide. 
     [Fourth Exemplary Embodiment] 
     Although in the first to third exemplary embodiments, the protrusion  21  of the second case  2  pushes the packing  3 , the protrusion  21  may be eliminated and the lower surface  24  of the second case  2  may push the packing  3 . In such a case, the height of the packing  3  is set to be greater than the height of the groove  11 . Further, the packing  3  is set in such a manner that when the packing  3  is pushed by the lower surface  24  of the second case  2 , the base part  33  of the packing  3  is hardly compressed, and the bending part  32  rotates in the bending direction to absorb the amount of protrusion from the groove  11  in the packing  3 , as shown in  FIG. 7 . 
     Such a configuration reduces the height of the groove  11 , thereby enabling reduction in the thickness of the waterproof structure and eventually the thickness of the electronic device. 
     The present invention is not limited to the above exemplary embodiments but can be modified as appropriate without departing from the scope. 
     In the above exemplary embodiments, the tip of the bending part  32  is formed in a roundish shape or sharply in order to reduce sliding resistance of the tip of the bending part  32  of the packing  3 , however, it is not limited to this. Specifically, the vicinity of the tip of the bending part  32  may be grained. Unevenness is formed on the vicinity of the tip of the bending part  32  by graining, and this reduces the friction with the guiding part  16  and the bottom surface  18  of the groove  11 . 
     Moreover, a lubricant such as oil may be applied to the vicinity of the tip of the bending part  32  and the guiding part  16  and the bottom surface  18  of the groove  11 . 
     Further, the vicinity of the tip of the bending part  32  may be formed of a material including a lubricant. 
     Incidentally, a following configuration using the above packing  3  can also realize the waterproof structure. 
     In the waterproof structure shown in  FIGS. 8 and 9 , the packing  3  of the first exemplary embodiment is disposed upside down. Specifically, as shown in  FIG. 8 , the bending part  32  of the packing  3  is disposed in a state not pushed by the second case  2  and facing obliquely upward and also outwardly (may be inwardly) of the first case  1 . As shown in  FIG. 9 , this packing  3  is pushed by the lower surface  24  of the second case  2 , in a similar manner as the fourth embodiment. Therefore, the height of the packing  3  is set to be greater than the height of a groove  110  in the first case  1 . However, as with the packing  3  of the first and second exemplary embodiments, the packing  3  may be pushed by the protrusion  21  of the second case  2 . 
     The groove  110  in the first case  1  includes a restraining part  111  and a relief part  112 . The base part  33  of the packing  3  is fitted in the restraining part  111 . The width dimension and height of the restraining part  111  are set to restrain the base part  33  well. This enables positioning of the packing  3  only by fitting the packing  3  in the restraining part  111  of the groove  110 . 
     The relief part  112  is formed in such a manner that the bending part  32  does not interfere the groove  110  when the bending part  32  of the packing  3  rotates in the bending direction. The relief part  112  of this exemplary embodiment is formed continuously with a surface  113  of the restraining part  111  that is outward of the first case  1  obliquely upward and also outwardly of the first case  1 . However, the shape of the relief part  112  is not especially limited, in short, the relief part  112  should only be formed in such a manner that the bending part  32  does not interfere the groove  11  when the bending part  32  rotates in the bending direction. 
     The base part  33  of the packing  3  is fitted in the restraining part  111  of the groove  110  in the first case  1  with such a configuration in the state that the bending part  32  of the packing  3  faces obliquely upward and also outwardly of the first case  1 . When the second case  2  is disposed to cover the opening of the first case  1  from above, as shown in  FIG. 9 , the packing  3  is pushed by the lower surface  24  of the second case  2  and the bending part  32  of the packing  3  rotates in a direction indicated by an arrow S, and the vicinity of the tip of the bending part  32  moves into the relief part  112  of the groove  110 . Since the base  33  does not move in the up-and-down direction at this time unlike the packing  3  of the first to fourth exemplary embodiments, it is possible to prevent the packing  3  from deteriorating. Additionally, as the width dimension of the restraining part  111  of the groove  110  can be substantially equivalent to that of the base part  33  of the packing  3 , the width dimension of the groove  110  can be less than that of the groove  11  according to the first to fourth exemplary embodiments. 
     Even when the packing  3  is used upside down in this way, as shown in  FIG. 9 , the bending part  32  of the packing  3  comes into contact with the lower surface  24  of the second case  2 , and the base part  33  of the packing  3  is firmly fitted in the restraining part  111  of the groove  110 , thereby enabling prevention of water ingress from outside the first case  1 . 
     Incidentally, as shown in  FIG. 10 , a configuration can be employed in which a pawl  38  protrudes from the base part  33  of the packing  3 , and the pawl  38  is hooked on a hook piece  120  formed to the first case  1  to fix the packing  3 . This enables elimination a part of the riser part  14  inward of the first case  1 . 
     The present application claims priority rights of and is based on Japanese Patent Application No. 2010-284625 filed on Dec. 21, 2011 in the Japanese Patent Office, the entire contents of which are hereby incorporated by reference. 
     Industrial Applicability 
     The present invention can be preferably used for a waterproof structure of electronic devices such as cell phones, smart phones, PDAs (Personal Digital Assistants), and tablet PCs (Personal Computers). 
     Reference Signs List 
     
         
           1  FIRST CASE 
           2  SECOND CASE 
           3  PACKING 
           4  BOLT 
           5  BOLT HOLE 
           6  PADDING 
           11  GROOVE 
           12  PAWL OF FIRST CASE 
           13  SPACE 
           14  RISER PART 
           15  UPPER SURFACE OF RISER PART 
           16  GUIDING PART 
           17  INWARD SURFACE OF GROOVE 
           18  BOTTOM SURFACE OF GROOVE 
           19  OUTWARD SURFACE OF GROOVE 
           21  PROTRUSION 
           22  REGION OF SECOND CASE TO BE IN CONTACT WITH RISER PART OF FIRST CASE 
           23  LOWER SURFACE OF PROTRUSION 
           24  LOWER SURFACE OF SECOND CASE 
           25  PAWL OF SECOND CASE 
           31  PROTRUSION OF PACKING 
           32  BENDING PART OF PACKING 
           33  BASE PART OF PACKING 
           34  CUTOUT OF BASE PART 
           35  SURFACE OF BASE PART OPPOSITE TO BENDING DIRECTION OF BENDING PART 
           36  SURFACE OF BENDING PART OPPOSITE TO BENDING DIRECTION 
           37  SURFACE OF BASE PART ON BENDING DIRECTION OF BENDING PART 
           38  PAWL OF PACKING 
           110  GROOVE 
           111  RESTRAINING PART 
           112  RELIEF PART 
           113  SURFACE OF RESTRAINING PART OUTWARD OF FIRST CASE 
           120  HOOK PIECE