PATENT ABSTRACT
A protective plate installation structure includes a base welded to a protection member, a clip for engaging the base, and a protective plate for protecting the protection member. The base has a first engaging portion, and a receiving portion. The clip has a second engaging portion at one end for engaging the first engaging portion when the clip is moved along an axis of the base, and an umbrella portion formed at the other end thereof. The protective plate has an installation opening so that when the clip is attached to the base through the installation opening, the protective plate is held between the umbrella portion and the receiving portion.

PATENT DESCRIPTION
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT 
   The present invention relates to a protective plate installation structure with a clip for installing a protective plate for protecting a fuel tank with a specific distance from a fuel tank formed of a plastic. 
   A fuel tank made of a plastic is located under a vehicle. Also, an exhaust pipe is located under or side of the fuel tank and heat is radiated therefrom. The fuel tank is located under the vehicle, so that the fuel tank may be damaged by a small rock bouncing off from a road. Accordingly, under or on a side of the fuel tank, a protective plate is installed with a clip to protect the fuel tank from the radiation heat and impact. 
   In Patent Document 1, as shown in  FIGS. 6 and 7 , a disc shape pedestal  102  is provided at an end of a clip holder  100  with a prismatic shape, and is attachable to a fuel tank  104 . A hollow portion  106  with a dented prismatic shape is provided at a center of one side surface  100 A of the clip holder  100 . An engaging opening  108  is provided at a center of the other side surface of the clip holder  100 , and a guide opening  110  is formed in a portion from the side surface  100 A to the lock opening  108  of the clip holder  100 . 
   A clip body  112  is capable of engaging the clip holder  100 . An insertion part  114  is formed in the clip body  112  for inserting into the hollow portion  106 , and the insertion part  114  shifts in parallel to insert into the hollow portion  106 . A lockable main body  116  is provided at a center of the insertion part  114  for locking with the engaging opening  108 . When the insertion part  114  is inserted into the hollow portion  106 , the insertion part  114  is guided to the engaging opening  108  along a guide opening  110 , and is locked with the engaging opening  108 . 
   A flat plate shape stopper  118  is formed on the main body  116  in parallel to the insertion part  114 , and both ends thereof are bent toward an opposite side of the insertion part  114 . A pair of claws  120  is formed on a tip of the main body  116 . The claws  120  penetrate through a penetration opening  122 A formed in the protective plate  122 , and engage a peripheral portion of an opening  126 A of the flat plate  126  formed in the protective plate  122 . In this state, the protective plate  122  is supported by the flat plate  126  and the stopper  118 , and the protective plate  122  is restricted to move right and left sides by an urging force of the stopper  118 . 
   The insertion part  114  of the clip body  112  is inserted into the hollow portion  106  of the clip holder  100  in a direction perpendicular to a direction that the claws  120  on the tip of the clip body  112  engage the peripheral portion of the opening  126 A of the flat plane  126 . Accordingly, an operation is performed in two directions, thereby making workability poor. 
   It is necessary to provide a space for the insertion part  114  to be shifted in parallel, so that the insertion part  114  of the clip body  112  is shifted in parallel and inserted in the hollow portion  106  of the clip holder  100 . It is difficult to take out the protective plate  112  for maintenance purpose. 
   Patent Document 1: Japanese Utility Model Publication No. 63-16244 
   In view of the problems described above, an object of the present invention is to provide a protective plate installation structure wherein workability is good and it is easy to remove a protective plate when maintenance of a vehicle is required. 
   Further objects and advantages of the invention will be apparent from the following description of the invention. 
   SUMMARY OF THE INVENTION 
   According to a first aspect of the present invention, a protective plate installation structure includes a base with a cylindrical shape formed of a plastic to be welded to a fuel tank formed of a plastic; a clip formed of a plastic for engaging the base; and a protective plate disposed between the clip and the base for protecting the fuel tank and having an installation opening for inserting the clip. A portion to be engaged is formed on the base, and an engaging portion is formed on one end of the clip for engaging the portion to be engaged when the clip moves along an axis of the base. An umbrella portion is formed on the other end of the clip for holding the protective plate with a receiving surface formed on one end of the base in a state that the engaging portion engages the portion to be engaged. 
   In the first aspect of the present invention, the base with a cylindrical shape is capable of adhering to the fuel tank, and the clip is capable of engaging the base. The installation opening is formed in the protective plate for inserting the clip. The portion to be engaged is formed on the base. The engaging portion is formed on the one end of the clip. In a state that the clip is inserted into the installation opening, when the clip moves along the axis of the base, the engaging portion engages the portion to be engaged. The umbrella portion is formed on the other end of the clip, so that the protective plate is supported between the umbrella portion and the receiving surface on the one end of the base in the state that the engaging portion engages the portion to be engaged. 
   When the clip moves along the axis of the base, the engaging portion of the clip engages the portion of the base to be engaged of the base, and the protective plate is supported between the umbrella portion of the clip and the receiving surface of the base. That is, when the protective plate is mounted on a side and under the fuel tank, an operation is performed in one direction, thereby making the operation easy. It is possible to mount the protective plate in a narrow space since the clip moves along the axis of the base. 
   According to a second aspect of the present invention, in the protective plate installation structure in the first aspect, an annular groove is provided inside an adhesion part of the base which adheres with the fuel tank, and a groove surface thereof is lowered relative to an adhesion surface of the fuel tank. 
   In the second aspect of the present invention, the annular groove is formed inside the adhesion part of the base, and the groove surface is lowered relative to the adhesion surface. Accordingly, when a weld residue generated from the base and the fuel tank when the base is welded to the fuel tank flows inside the adhesion part of the base, the groove surface blocks the weld residue. Therefore, the weld residue does not enter an inside wall of the base, so that the weld residue does not prevent the clip from inserting when the base engages the clip. 
   According to a third aspect of the present invention, in the protective plate installation structure in one of the first and second aspects, the engaging portion includes a pair of plate pieces capable of tilting and provided on a tube of a main body of the clip, and claws formed on tips of the plate pieces. The plate pieces project from an opening formed in the umbrella portion to be capable of approaching with each other, so that the claws are disengaged from the portion to be engaged when the plate pieces approach with each other. 
   In the third aspect of the present invention, a pair of the plate pieces is provided on the tube of the main body of the clip to be capable of tilting, and the claws are formed on the tips of the plate pieces. The opening is provided in the umbrella portion. When the plate pieces approach with each other through the opening, the claws are disengaged from the portion to be engaged. Accordingly, it is possible to remove the clip from the base for the vehicle maintenance, and it is easy to uninstall the protective plate. 
   According to a fourth aspect of the present invention, in the protective plate installation structure in one of the first to third aspects, the base is formed of a material same as that of a surface layer of the fuel tank. Accordingly, the base is surely welded to the surface layer of the fuel tank. 
   As described above, in the first aspect of the present invention, the engaging portion of the clip engages the portion to be engaged of the base when the clip slides along the axis of the base, so that the protective plate is supported between the umbrella portion of the clip and the receiving part of the base. In other words, when the protective plate is installed under or on the side of the fuel tank, an operational direction is one direction. Accordingly, it is easy to operate, and it is possible to install the protective plate in a narrow space. 
   In the second aspect of the present invention, the annular groove is formed inside the adhesion part of the base, and the groove surface is lowered relative to the adhesion surface. Accordingly, when a weld residue generated from the base and the fuel tank when the base is welded to the fuel tank flows inside the adhesion part of the base, the groove surface blocks the weld residue. Therefore, the weld residue does not enter an inside wall of the base, so that the weld residue does not prevent the clip from inserting when the base engages the clip. 
   In the third aspect of the present invention, the clip can be easily detached from the base for the vehicle maintenance, so the protective plate is uninstalled easily. 
   In the fourth aspect of the present invention, the base is formed of the same material as the surface layer of the fuel tank. Accordingly, the base is surely welded to the surface layer of the fuel tank. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a protective plate installation structure according to the present invention; 
       FIG. 2  is an exploded perspective view of the protective plate installation structure according to the present invention; 
       FIG. 3  is a cross-sectional view of the protective plate installation structure in a state that a base is welded to a fuel tank; 
       FIGS. 4(A) to 4(C)  are cross-sectional views of the protective plate installation structure in a state that the protective plate is attached to a base with a clip; 
       FIGS. 5(A) and 5(B)  are cross-sectional views of the protective plate installation structure in a state that the clip is removed from the base; 
       FIG. 6  is an exploded perspective view of a conventional protective plate installation structure; and 
       FIG. 7  is a cross-sectional view of the conventional protective plate installation structure. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Hereunder, embodiments of the present invention will be explained with reference to the accompanying drawings. An exhaust pipe is provided under or side of the plastic fuel tank located under a vehicle, and radiates radiation heat. A small rock may bounce off from a road and hit the fuel tank. For this reason, a protective plate with heat resistance and impact resistance is provided under or side of the fuel tank to protect the same from the radiation heat and impact. 
   A surface layer of the plastic fuel tank  10  shown in  FIGS. 1 to 3  is made of polyethylene, and a cylindrical shaped polyethylene base  12  is capable of adhering on the surface of the fuel tank  10 . A surface of one side of the base  12  is an adhesion part  14  to be adhered to the fuel tank  10 . The surface is melt by frictional heat from spinning, and contacts the surface of the fuel tank  10  to melt each other and solidifies. An annular groove  16  is formed inside the adhesion part  14 , and a groove surface  16 A of the annular groove is formed lower than the adhesion surface  14 A of the adhesion part  14 . 
   The other side surface of the base  12  is a receiving surface  20  capable of contacting the protective plate  18  for protecting the fuel tank  10 . The receiving surface  20  of the base  12  has a small diameter (small diameter portion or hole  22 ), and a step  24  as a portion to be engaged is formed between the small diameter portion  22  and an inner circumference wall  12 A. A surface portion  20 A is formed on an edge of the inner circumference of the receiving surface  20  (corner portion of the receiving surface  20  of the small diameter portion  22 ). 
   Indentation parts  26  are formed in the outer circumference wall  12 B of the base  12  along the perimeter direction with a prescribed interval in between. With the indentation parts  26 , a perimeter wall is prevented from sinking after molding, and stay parts  27  are formed between indentations  26  for strengthening the base  12 . 
   A clip  28  shown in  FIGS. 2 and 4(A)  to  4 (C) is made of nylon and provided with a cylindrical shape main body  30  capable of inserting the small diameter portion  22 , so that the clip  28  can be inserted into an installation opening  18 A formed in the protective plate  18 . A pair of plate pieces  32  is provided on the main body  30  and capable of tilting relative to the main body  30 . At tips of the plate pieces  32 , claws  34  project from an outer circumference surface of the main body  30 . 
   When the main body  30  is penetrated through the installation opening  18 A of the protective plate  18 , the claws  34  contact the installation opening  18 A and the plate pieces  32  tilt to reduce a diameter, so that the claws  34  can be penetrated through the installation opening  18 A. After the claws  34  penetrate through the installation opening  18 A, the claws  34  and the plate pieces  32  are restored. 
   A distance between the plate pieces  32  is slightly smaller than an inner diameter of the installation opening  18 A. Accordingly, when the claws  34  penetrate through the installation opening  18 A and the plate pieces  32  restore, end portions of the plate pieces  32  are placed in the installation opening  18 A and capable of contacting an inner circumference edge of the installation opening  18 A. Outside faces of the plate pieces  32  become flat faces for preventing the clip  28  from rotating, and also preventing the protective plate  18  from displacing horizontally in a state that the plate pieces  32  contact the inner circumference edge of the installation opening  18 A. 
   When the main body  30  is penetrated through the installation opening  18 A, the main body  30  can be penetrated through the small diameter portion  22 . When the claws  34  pass through the small diameter portion  22 , the claws  34  shrink in a diameter, and the plate pieces  32  tilt. After the claws  34  pass through the small diameter portion  22 , the plate pieces  32  and the claws  34  restore. 
   In a state that the plate pieces  32  and the claws  34  restore, the upper surfaces  34 A of the claws  34  abut against the lower surface  24 A of the step  24 , so that the clip  28  engages the base  12 . Top portions of the claws  34  (not shown) have a curvature radius same as the inside diameter of the inner circumference wall  12 A of the base  12 . Accordingly, the upper surfaces  34 A of the claws  34  can evenly contact the lower surface  24 A of the step  24  over a width direction of the upper surfaces  34 A of the claws  34 . 
   An umbrella portion  36  with a conical shape is provided on the other side of the main body  30 . As shown in  FIGS. 5(A) and 5(B) , the umbrella portion  36  has an end thinner than a base, so that the end elastically deforms more. In a state that the claws  34  engage the step  24 , the umbrella portion  36  supports the protective plate  18  with the receiving surface  20 , and the end portion of the umbrella  36  presses the protective plate  18  against the receiving surface  20 , thereby strongly holding the protective plate  18 . 
   An opening  38  is formed at a middle of the umbrella  36 , and the end portions of the plate pieces  32  are exposed through the opening  38 . The opening  38  is formed as an elongated opening longer than the interval of the plate pieces  32 . Accordingly, it is possible to insert a tool such as a forceps  44  outside the plate pieces  32 . The forceps  44  moves the ends of the plate pieces  32  close together through the opening  38 , thereby tilting the plate pieces  32 . 
   An effect of the protective plate installation according to the present invention will be described in detail next. As shown in  FIGS. 4(A) to 4(C) , the small diameter portion  22  is provided on the receiving surface  20  of the base  12 , and the step  24  (portion to be engaged) is formed between the inner circumference wall  12 A and the small diameter portion  22 , so that the claws  34  of the clip  28  engage the step  24 . Accordingly, the claws  34  can engage any part of the step  24  in any perimeter direction, thereby improving workability. 
   The tips of the claws  34  have a curvature radius same as an inner diameter of the inner circumference wall  12 A of the base  12 , so that the upper surfaces  34 A of the claws  34  evenly contact the lower surface  24 A of the step  24  across a width direction of the upper surfaces  34 A of the claws  34 , thereby obtaining strong engagement between the clip  28  and the base  12 . 
   As shown in  FIG. 2  and  FIG. 4(A) to 4(C) , when the clip  28  slides along the axis of the base  12 , the claws  34  engage the step  24 , so that the protective plate  18  is supported between the receiving surface  20  of the base  12  and the umbrella portion  36 . That is, when the protective plate  18  is installed on a side or under the fuel tank, an operation direction is one direction. Accordingly, the operation is easy and it is possible to install the protective plate  18  in a narrow space. 
   As shown in  FIG. 3 , the annular groove  16  is formed inside the adhesion part  14  of the base  12 , and the groove surface  16 A is lower than the adhesion surface  14 A. When the base  12  and the fuel tank  10  are welded, a weld residue  42  is formed and flows inside the adhesion part  14  of the base  12 . In this case, the groove surface  16 A blocks the weld residue  42  not to enter the inside wall  12 A of the base  12 , and not to interrupt the clip  28  from inserting. 
   The base  12  is made of polyethylene, i.e., a same material as a surface of the fuel tank  10 . Accordingly, when the base  12  adheres with the fuel tank  10 , the surface of the base  12  and the fuel tank  10  melt in a same way, so that the base  12  can be adhered surely. 
   The clip  28  is placed outside the protective plate  18 , i.e., a side of an exhaust pipe (not shown), and is made of nylon with high heat resistance. Nylon has lower impact resistance as compared with polyethylene, i.e., the material of the base  12 . Accordingly, when the protective plate  18  receives an excessive amount of impact, the clip  28  is broken before the base  12 . Accordingly, when the protective plate  18  receives an impact larger than a prescribed amount, the clip  28  absorbs the impact and is broken, thereby preventing the impact from transmitting to the base  12 . When the protective plate  18  receives the impact larger than the prescribed amount, the main body  30  of the clip  28  located inside the installation opening  18 A of the protective plate  18  also absorbs the impact, so that a connected portion between the umbrella  36  and the main body  20  is broken. As described above, when the protective plate  18  receives the impact larger than the prescribed amount, the clip  28  is broken, thereby preventing the impact from transmitting to the fuel tank  10  through the base  12 . 
   The opening  38  is formed at the middle of the umbrella portion  36 , and the end portions of the plate pieces  32  are exposed through the opening  38 , so that the plate pieces  32  get close each other through the opening  38 . Accordingly, it is possible to tilt the plate pieces  32  and remove the claws  34  from the step  24  through the opening  38 , thereby removing the clip  28  from the base  12 . Therefore, the protective plate  18  can be removed easily for the vehicle maintenance. 
   In the embodiment, the base  12  and the surface layer of the fuel tank  10  are made of polyethylene. The material is not limited thereto as far as the base  12  is securely adhered to the fuel tank  10 . The base  12  is made of polyethylene and the clip  28  is made of nylon. Alternatively, the base  12  and the clip  28  may be made of a same material as far as the base  12  has mechanical strength stronger than that of the clip  28 . 
   The disclosure of Japanese Patent Application No. 2004-165755, filed on Jun. 3, 2004, is incorporated in the application. 
   While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.