Abstract:
A gasket that serves to shield electromagnetic waves from an electronic apparatus that has a housing that includes a first surface and a second surface opposite to the first surface, the gasket being squeezed into a perforation hole that perforates the first and second surfaces, and fixed onto the housing includes a lid part that contacts the first surface and serves as a flat sprig, and an insertion part that is to be inserted into the perforation hole in the housing, and includes an engagement part, coupled with the support part, which at least partially projects from the perforation hole in the housing and contacts the second surface, wherein the engagement part includes a leg coupled with the support part, and a foot that is coupled with the leg and forms an acute angle relative to the leg.

Description:
[0001]    This application claims a benefit of priority based on Japanese Patent Application. No-2002-367762, filed on Dec. 19, 2002, which is hereby incorporated by reference herein in its entirety as if fully set forth herein.  
         BACKGROUND OF THE INVENTION  
         [0002]    Along with recent widespread electronic apparatuses, the supply high-performance electronic apparatuses have been increasingly demanded. For example, conventional computers and communication controllers as exemplary electronic apparatuses have used gaskets that can be mounted onto a housing for resistance to electromagnetic waves from a printed plate (as disclosed, for example, in Japanese Patent Publication No. 8-274485). This gasket is required to have a physical structure to shield electromagnetic waves as well as a mechanical structure that facilitates mounting onto an electronic-apparatus housing and prevents falling off from the housing.  
           [0003]    A description will be given of a conventional gasket  10  with reference to FIGS. 20 and 21. Here, FIG. 20 is a perspective overview of the conventional gasket  10 . As illustrated, the gasket includes a lid part  20  and an insertion part  30 . Due to the lid part  20  and insertion part  30 , the gasket  10  forms an approximately π shaped section. The insertion part  30  is a portion to be inserted into a housing, and includes a pair of support parts  32  each having an approximately rectangular parallelepiped shape, and a pair of engagement parts  34  each having an approximately right triangle pole shape.  
           [0004]    [0004]FIG. 21 is a sectional view before and after the gasket  10  is inserted into a computer housing  2 . The housing  2  has a perforation hole  4 . Each support part  32  is slightly longer than the perforation hole  4  in the housing  2 . The gasket  10  is made of an elastic member, and thus a pair of support parts  32  and engagement parts  34  deform so that they approach to each other while the gasket  10  is being inserted into the housing  2 , and return so that they separate from each other after the engagement parts  34  project from the perforation hole  4 .  
           [0005]    As shown in FIG. 21, when the gasket  10  is inserted into the housing  2 , the lid part  20  contacts a top surface  6  of the housing  2 , the support parts  32  of the insertion part  30  are located in the perforation hole  4 , and the engagement parts  34  project from a bottom surface  8  of the housing  2  so that bracket parts  35  contact the peripheral of the perforation hole  4 . When the engagement parts  34  contact the bottom surface  8 , the lid part  20  applies an elastic force as a flat spring to the housing  2 .  
           [0006]    Thus, the conventional gasket  10  is configured so that once it is inserted into the housing  2 , the bracket parts  35  of the engagement parts  34  are hooked on the bottom surface of the housing  2  even when it is attempted to be pulled out and it does not come off easily.  
           [0007]    [0007]FIG. 22 is a graph of exemplary reactions in mounting the gasket  10  onto and pulling off the gasket  10  from the housing  2 . FIG. 22 shows results of two experiments F 1 RF 2  add F 2 RF 2 . As illustrated, it is understood that the mounting reaction is 360 g (180 g×2) per width, and the puling-off reaction is 140 g (70 g×2) per width. This means that the pulling-off force is smaller than the mounting force and the gasket  10  is easily pulled off. In other words, the conventional gasket  10  has not had such a structure as meets a mechanical requirement of easy mounting and hard pulling off. When the gasket  10  comes off, electromagnetic waves and noises leak from a printed circuit board in an electronic apparatus, undesirably causing, for example, a television around the electronic apparatus to distort screen images. In addition, the coming-off gasket  10  also causes a problem of a loss due to its small size. Therefore, it is preferable that the pulling force is larger than the mounting force and the mounting force is as small as possible.  
         BRIEF SUMMARY OF THE INVENTION  
         [0008]    Accordingly, it is an exemplary object of the present invention to provide a gasket that is structurally easily mounted onto and hard to come off from an electronic apparatus, and the electronic apparatus having the gasket.  
           [0009]    In order to achieve these and other objects, a gasket of one aspect according to the present invention that serves to shield electromagnetic waves from an electronic apparatus that has a housing that includes a first surface and a second surface opposite to the first surface, the gasket being squeezed into a perforation hole that perforates the first and second surfaces, and fixed onto the housing includes a lid part that contacts the first surface and serves as a flat sprig, and an insertion part that is to be inserted into the perforation hole in the housing, wherein the insertion part includes a support part that extends from an approximate center of the lid part and is accommodated into the perforation hole, and an engagement part, coupled with the support part, which at least partially projects from the perforation hole in the housing and contacts the second surface, wherein the engagement part includes a leg coupled with the support part, and a foot that is coupled with the leg and forms an acute angle relative to the leg. A gasket as another aspect according to the present invention that serves to shield electromagnetic waves from an electronic apparatus that has a housing that includes a first surface and a second surface opposite to the first surface, the gasket being squeezed into a perforation hole that perforates the first and second surfaces, and fixed onto the housing includes a lid part that contacts the first surface and serves as a flat sprig, and an insertion part that is to be inserted into the perforation hole in the housing, and includes an engagement part, coupled with the support part, which at least partially projects from the perforation hole in the housing and contacts the second surface, wherein the engagement part includes a leg coupled with the support part, and a foot that is coupled with the leg and forms an acute angle relative to the leg.  
           [0010]    The foot may have a tip that is to contact the second surface. The leg may diverge from an approximate center of the support part. The engagement part may have a projection that prevents the gasket from coming off and projects from the foot. The foot may have a tip that can contact the second surface, and has an acute shape in sectional that prevents coming off of the gasket. The support part may have a projection opposite to the perforation hole. The engagement part may have an anchor shape. The leg may extend from the support part and forms an acute angle relative to the support part.  
           [0011]    A gasket as another aspect according to the present invention that serves to shield electromagnetic waves from an electronic apparatus that has a housing that includes a first surface and a second surface opposite to the first surface, the gasket being squeezed into a perforation hole that perforates the first and second surfaces, and fixed onto the housing includes a lid part that contacts the first surface and serves as a flat spring, and an insertion part that is to be inserted into the perforation hole in the housing, and includes an engagement part, coupled with the support part, which at least partially projects from the perforation hole in the housing and contacts the second surface, wherein the engagement part includes a pair of projections that extend in opposite directions, which do not contact each other while the gasket is being inserted into the housing, and contact each other while the gasket is being pulled off from the housing.  
           [0012]    The instant inventors have experimentally confirmed that a gasket having any one of the above structures is easily mounted onto and hard to come off from an electronic apparatus. An electronic apparatus having any one of these gaskets constitute one aspect of the present invention.  
           [0013]    Other objects and further features of the present invention will become readily apparent from the following description of the embodiments with reference to accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a perspective overview showing a gasket body as one embodiment according to the present invention.  
         [0015]    [0015]FIG. 2 is a sectional view before and after the gasket body shown in FIG. 1 is inserted into a housing of an electronic apparatus.  
         [0016]    [0016]FIG. 3 is a graph showing reactions in mounting the gasket body shown in FIG. 1 onto and pulling off the same from the housing of the electronic apparatus.  
         [0017]    [0017]FIG. 4 is a partial sectional view showing a variation of a projection of a support part in the gasket body shown in FIG. 1.  
         [0018]    [0018]FIG. 5 is a partial sectional view showing a variation of an engagement part of the gasket body shown in FIG. 1.  
         [0019]    [0019]FIG. 6 is a partial sectional view showing a variation of the gasket body shown in FIG. 1.  
         [0020]    [0020]FIG. 7 is sectional views before and after the gasket body shown in FIG. 6 is inserted into the housing of an electronic apparatus.  
         [0021]    [0021]FIG. 8 is a partial sectional view showing a variation of a projection of a support part in the gasket body shown in FIG. 6.  
         [0022]    [0022]FIG. 9 is a perspective overview of a gasket as one embodiment according to the present invention that has the gasket body shown in FIG. 1.  
         [0023]    [0023]FIG. 10 is a partial sectional view showing another variation of the gasket body shown in FIG. 1.  
         [0024]    [0024]FIG. 11 is a perspective overview of a network device as one example of an inventive electronic apparatus.  
         [0025]    [0025]FIG. 12 is a view showing a plug in unit structure that is removably accommodated into the electronic apparatus shown in FIG. 11.  
         [0026]    [0026]FIG. 13 is a perspective overview showing the plug in unit shown in FIG. 12 that is being removed from the network device shown in FIG. 11.  
         [0027]    [0027]FIG. 14 is an enlarged perspective view of part A shown in FIG. 13.  
         [0028]    [0028]FIG. 15 is a view for explaining a shield structure of the network device shown in FIG. 11.  
         [0029]    [0029]FIG. 16 is a perspective overview of an improvement of a conventional gasket.  
         [0030]    [0030]FIG. 17 is a perspective overview of an improvement of the conventional gasket.  
         [0031]    [0031]FIG. 18 is a perspective overview of another improvement of the conventional gasket.  
         [0032]    [0032]FIG. 19 is a perspective overview of another improvement of the conventional gasket.  
         [0033]    [0033]FIG. 20 is a perspective overview of the conventional gasket.  
         [0034]    [0034]FIG. 21 is a sectional view before and after the gasket shown in FIG. 20 is inserted into a computer housing.  
         [0035]    [0035]FIG. 22 is a graph showing exemplary reactions in mounting in the gasket shown in FIG. 20 onto and pulling off the gasket from the housing. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0036]    The instant inventors have conducted simulations about mounting and pulling-off forces while partially improving a structure of the conventional gasket  10 . A description will now be given of modified structures and their effects.  
         [0037]    The instant inventors initially reviewed an increase of a pulling-off force by enlarging rigidity of the insertion part  30 . Accordingly, a gasket  10 A shown in FIG. 16 is produced which fills between the pair of support parts  32  to form a single member, and its reaction was simulated. The gasket  10 A shown in FIG. 16 is similar to the gasket  10  except that it has a single support part  32 A. Here, FIG. 16 is a perspective overview of the gasket  10 A. When the gasket  10 A is inserted into the perforation hole  4 , the bracket parts  35  of the engagement part  34  crush due to plastic deformation, but mounting and pulling-off reactions increase.  
         [0038]    Next, the instant inventors have reviewed an extension of a length of the bracket part  35  of each engagement part  34  shown in FIG. 20 in order to increase the contact area with the bottom surface  8  and enhance consequently the puling-out force. Since the mounting reaction increases when the bracket part  35  extends in a direction perpendicular to the support part  32  as shown in FIG. 20, a gasket  10 B was prepared and its reaction was simulated. The gasket  10 B includes a pair of engagement parts  34 A each having a bracket part  35 A that extends and forms an acute angle relative to the support part  32 . The gasket  10 B shown in FIG. 17 is similar to the gasket  10  except that it has the bracket parts  35 A. Here, FIG. 17 is a perspective overview of the gasket  10 B. It was found that when the gasket  10 B was inserted into the perforation hole  4 , the bracket parts  35 A of the engagement parts  34 A sufficiently deformed, thereby decreasing the mounting reaction and increasing the pulling-off reaction.  
         [0039]    Next, the instant inventors have reviewed a pulling-off prevention by a pair of engagement parts  34  that approach to each other mounted onto the housing  2 . Accordingly, a gasket  10 C was prepared and its reaction was simulated. The gasket  10 C includes the engagement parts  34  shown in FIG. 20 that have projections  36  inside the engagement parts  34 . The gasket  10 C shown in FIG. 18 is similar to the gasket  10  except that it has the projections  36 . Here, FIG. 18 is a perspective overview of the gasket  10 C. It was found that when the gasket  10 C was inserted into the perforation hole  4 , the projections  36  of the engagement parts  34  crushed due to plastic deformation, but increased the inserting and puling-off reactions.  
         [0040]    Next, the instant inventors have conducted a simulation by providing the support parts  32  shown in FIG. 20 with projections  33  opposite to the perforation hole  4 . A gasket  10 D shown in FIG. 19 is similar to the gasket  10  except that it has the projections  33 . Here, FIG. 19 is a perspective overview of the gasket  10 D. It was found that the gasket  10 D showed the decreased mounting reaction and the increased pulling-off reaction.  
         [0041]    A description will be given of a gasket  100  as one embodiment according to the present invention with reference to the accompanying drawings. The gasket  100  has been prepared considering the results of the above simulations. Here, FIG. 1 is a perspective overview showing a gasket body  101 . FIG. 2 is a sectional view before and after the gasket body  101  is inserted into the computer housing  2 . In the following description, reference numerals with capitals are variations of members assigned reference numerals without alphabets, and generalized by reference numerals without alphabets unless otherwise specified.  
         [0042]    The gasket  100  includes, as shown in FIG. 9, a gasket body  101  made of an elastic material, such as silicon rubber, a cotton  190  that has an approximately semicircle section and covers the gasket body  101 , and (electrically) conductive cloth  192 . The conductive cloth  192  serves to shield electromagnetic waves, and the cotton  190  provides the conductive cloth  192  with elasticity and prevents damages of the conductive cloth  192 . Since the cotton  190  and conductive cloth  192  may apply any material, manufacture and attachment known in the art of the gasket, a detailed description thereof will be omitted.  
         [0043]    The gasket body  101  includes, as shown in FIG. 1, a lid part  110  and an insertion part  120 , and is made of an elastic material, such as silicon rubber, similar to the gasket  20 . The basket body  101  forms an approximately π shape due to the lid part  110  and the insertion part  120 .  
         [0044]    The lid part  110  contacts the surface  6  of the housing  2  and serves as a flat spring. The lid part  110  has an approximately V-shaped section that extends in a direction M in FIG. 1, and contacts the surface  6  of the housing  2  through a pair of ends  112 . The ends  112  are chamfered or formed like a curve, and the shape differs from the nodule lid part  20 . However, the lid part  110  has substantially the same function as the lid part  20 . Therefore, the ends  112  of the lid part  110  may have a shape similar to or different from the lid part  20 . The elastic force of the flat spring is adjustable by adjusting a distance L between a tip of the center part of the lid part  110  and part of the end  112  that contacts the surface  6 . Due to the flat spring function, the lid part  110  is deformable when the center edge line  114  is pressed after inserted into the housing  2 . The cotton  190  and the conductive cloth  192  are attached to the top surface of the lid part  110 .  
         [0045]    The insertion part  120  is a portion that is inserted into the perforation hole  4  in the housing  2 , as shown in FIGS. 1 and 2, and includes a support part  130  and a pair of engagement parts  140 .  
         [0046]    The support part  130  extends from an approximate center of the lid part  110  and is accommodated in the perforation hole  4 . The support part  130  includes a base  132 , and a pair of projections  134 , provided on the base  132 , which face the perforation hole  4 .  
         [0047]    The support part  130  of the instant embodiment is a single member, different from the pair of support parts  32  of the gasket  10  shown in FIG. 20. In other words, it has the base  132  that has an approximately rectangular parallelepiped shape that fills the inside space in the pair of support parts  32 . This is because the pulling-off reaction increases from the simulation result of the gasket  10 A shown in FIG. 16. A width W 1  of the base  132  of the instant embodiment is set, for example, 40% to 60% of the width W of the perforation hole  4 .  
         [0048]    A pair of projections  134  project from the support parts  130  toward an inner surface of the perforation hole  4 , contact the inner surface of the perforation hole  4  when the gasket  100  is pulled off, increasing the resistance and pulling-off reaction. The projection  134  is set, for example, to be about 20% to 30% of the width of the perforation hole in the instant embodiment. The width W 1  of the base  132  may be increased instead of providing the base  132  with projections  134 , although the width W must be increased within a range that does not cause the plastic deformation of the engagement part  140 .  
         [0049]    Each projection  134  of the instant embodiment exemplarily has an approximately semicircular shape. However, they may extend in an upper oblique direction in order to increase the reaction in pulling off the gasket  100 . The number of projections  134  is not limited to one. FIG. 4 shows an enlarged side view of two projections  134 A at one side of two pairs of projections  134 A that extend from the base  132  in upper oblique directions. The upper and lower projections  134 A may have different shapes and lengths. The upper oblique extension enables the projections  134 A to deform while assisting in an insertion, and apply resistance to the inner surface of the perforation hole  4  so as to prevent pulling off. A tip of the projection  134 A may be enlarged in order to ice the resistance with the inner surface of the perforation hole  4  at the time of pulling off.  
         [0050]    The engagement parts  140  diverge like an approximately V shape from an approximate center of the support part  130 . They partially project from the perforation hole  4  in the housing  2  and contact the bottom surface  8  of the housing  2 , as shown in FIG. 2.  
         [0051]    Each of a pair of engagement parts  140  includes a leg  141  coupled with the base  132  of the support part  130 , and a foot  142  arranged to form an acute angle relative to the leg  141 .  
         [0052]    In the instant embodiment, the leg  141  diverges into two from an approximate center of the base  132  of the support part  130  and has a divergence angle θ 2  of an acute angle. As will be described with reference to FIG. 10, the present invention does not require the leg  141  from diverging from the support part  130  or the angle θ 2  from the support part  130  to be an acute angle. The leg  141  is elastically deformable and serves to support the foot  142 . The length If the leg  141  is set to be a length connectible to the bottom surface  8 .  
         [0053]    The foot  142  is arranged so that an angle θ 1  is acute relative to the leg  141 . This is because the simulation shown in FIG. 20 by the instant inventors shows that the engagement parts  140  easily plastically deform when they extend from the support part  32  perpendicularly, and the reaction in pulling off the gasket decreases when the angle θ 1  is an obtuse angle. The foot  142  has a connection-part  144   a  coupled with the leg  144   a , and a tip  144   b.    
         [0054]    In the instant embodiment, the connection part  144   a  is a heel of the foot- 142 , but the present invention allows the leg  141  to be connected to the foot  142  at its center.  
         [0055]    The tip  144   b  contacts the bottom surface  8  of the housing  2 . The tips  144   b  must be located outside the projections  134 , because when they are located inside the projections  134 , they do not contact the inner surface of hole  4  or the bottom surface  8  and cannot serve as an engagement function.  
         [0056]    When the tip  144   b  changes its shape from a circular section to an acute section, as shown in FIG. 5, the tip  144   b  preferably deforms so as to assist an insertion and applies the resistance to the bottom surface  8  so as to prevent pulling off. Here, FIG. 5 is an enlarged sectional view of a foot as a variation of the foot  142  shown in FIG. 1. If necessary, the resistance may be increased by roughing a surface of the cut end  145  and/or applying a sticky material. The cut end  145  must face the bottom surface  8 , because the cut end  145  if facing opposite to the bottom surface  8  would cause increased reaction in mounting the gasket.  
         [0057]    [0057]FIG. 2 is a sectional view before and after the gasket  100  is inserted into a computer housing  2 . The engagement parts  140  have such a length that when the gasket  100  is inserted into the housing  2 , the tip  144   b  of the engagement part  140  is located near a boundary between the perforation hole  4  and the inner surface  8 .  
         [0058]    In inserting the gasket  100  into the housing  2 , a user sets the gasket  100  on the perforation hole  4 , and squeezes it by pressing the lid part  110 . If necessary, a pair of feet  142  are made narrower by a thumb and a forefinger in squeezing the gasket  100 . Since the gasket  100  is made of an elastic member, the feet  142  bend after contacting the perforation hole  4 , and deforms so that the pair of engagement parts  140  approach to each other, allowing the gasket  100  to be squeezed.  
         [0059]    After the gasket  100  is inserted into the housing  2 , the engagement parts  140  project from the perforation hole  4 , and then return so as to be apart from each other. As shown in FIG. 2, the ends  112  of the lid part  110  contact the top surface  6  of the housing, the support part  130  of the insertion part  120  is located in the perforation hole  4 , and the engagement part  140  is located so that the tips  144   b  are located near the boundary between the bottom surface  8  and the perforation hole  4 . The lid part  110  may apply the elastic force as a flat spring to the housing  2  when the engagement part  140  contacts the bottom surface  8 .  
         [0060]    Thus, after the gasket  100  is inserted into the housing  2 , the tips  144   b  of the feet  142  of the engagement part  140  are caught by the bottom surface  8  and the perforation hole  4  of the housing  2 , whereby the gasket  100  does not structurally easily fall off from the housing  2  once it is mounted onto the housing  2 .  
         [0061]    [0061]FIG. 3 is a graph showing reactions in mounting the gasket body  101  onto and pulling off the from the housing  2 , showing a result of two experiments (F1RF2 — 900001 and F1RF2 — 90002). As illustrated, the mounting reaction was 320 g (160 g×2) per width, and the pulling-off reaction was 400 g (200 g×2) per width.  
         [0062]    In comparison with a result shown in FIG. 22, it is understood that the pulling-off force is greater than the mounting force, preventing easy coming off. In addition, the mounting force decreases from 360 g to 320 g while the pulling-off force increases from 140 g to 400 g. Therefore, the gasket  100  is more easily mounted than the gasket  10  and enhances the coming-off prevention function. Thus, the gasket  100  meets the mechanical requirement of easy mounting and hard coming-off more satisfactorily than the conventional.  
         [0063]    [0063]FIG. 6 shows a gasket  101 A as a variation of the gasket body  101 . The basket body  101 A has the engagement part  140 A different from the engagement part  140 , which includes projections  148  that face each other at a heel of each foot  142 A.  
         [0064]    Each projection  148  prevents the gasket body  101 A from being pulled off as described with reference to FIG. 7 and protrudes from each foot  142 A.  
         [0065]    [0065]FIG. 7A is a sectional view shown a state of the projection  148  before and after the gasket  100 A is inserted into the housing  2 . As illustrated, when the gasket body  101 A is being inserted into the housing  2 , a pair of feet  142  bend toward the inside after contacting the perforation hole  4 , and consequently deform so that heels separate from each other. Therefore, the projections  148  provided at the heels of the feet  142  deform so that they separate from each other, not hindering an insertion of the gasket  100 A.  
         [0066]    On the other hand, FIG. 7B is a sectional view showing a state of the projection when pulling off of the gasket body  101 A starts and ends. The instant inventors have found that when the gasket  100 A is inserted into the housing  2 , the feet  142  do not open perfectly outside the perforation hole  4  in most cases, as shown in FIG. 7A, but the tips  144   b  are located near the boundary between the bottom surface  8  and the inner surface of the perforation hole  4 . In addition, the instant inventors have found that when the gasket  100 A is pulled off in that state, the tips  144   b  moves up while slipping along the inner surface of the perforation hole  4 .  
         [0067]    Therefore, in an attempt to pull off the gasket  100 A from the housing when there are projections  148 , as shown in FIG. 7B, the tips  144   b  are caught by the inner surface of the perforation hole  4  and deform to the outside, whereby the heels deform and approach to each other consequently. Therefore, the projections  148  provided at the heels of the feet  142  deform, approach to each other and contact finally. When the gasket  100 A continues to be pulled off, the pulling-off force resists the elastic force after the projections  148  contact and the force necessary for the plastic deformation deeding upon a size of the projection  148 . Therefore, the projection  148  may increase the pulling-off force. According to the simulation by the instant inventors, the pulling-off force was about 800 g, an about sextuple increase.  
         [0068]    The present invention do not limit a size and a shape of the projection  148 , but the size and shape are preferably determined so that the projections  148  contact when the gasket body  101  is pulled off, because if the projections  148  do not contact each other when the gasket body  101 A is pulled off they do not contribute to an increase of the pulling-off force. However, it is optional whether the projections  140  plastically d form because the excessively large pulling-off force with a demand for exchange of a deteriorated gasket would make it difficult to exchange the gasket.  
         [0069]    It is sufficient that the projections  148  act to prevent pulling off of the gasket  100 , and the present invention covers the number of projections  148  of one and three or more.  
         [0070]    [0070]FIGS. 8A to  8 C show an example that provides the gasket body  10 A with the cut ends  145 , similar to FIG. 5. FIG. 8A is a partial section showing the cut end  145  and the projection  148  before the gasket body  101 A is inserted into the housing  2 . FIG. 8B is a partial section showing the cut end  145  and the projection  148  before and after the gasket body  101 A is inserted into the housing  2 . FIG. 8C is a sectional view showing the cut end  145  and the projection  148  when pulling off of the gasket body  101 A from the housing  2  starts and ends.  
         [0071]    As shown in FIG. 8B, the cut end  145  and the projection  148  do not prevent an insertion of the gasket, and the cut end  145  is located near the boundary between the perforation hole  4  and the bottom surface  8 . In addition, the cut end  145  slightly opens to the outside. As shown in FIG. 8C, the cut end  145  is caught by the bottom surface  8  when the gasket is pulled off making pulling off difficult.  
         [0072]    [0072]FIG. 10 shows a gasket body  101 B as another variation of the gasket body  101 . The gasket body  101 B has an engagement part  140 B that is different in that it includes feet  142 B with an anchor shape.  
         [0073]    More specifically, the engagement part  140 B includes legs  141 B coupled with the support part  132 , and legs  14213  coupled with the legs  141 B. The legs  141 B of the instant embodiment is formed as a single member without diverging from the support part  130 . Similar to FIG. 1, the length of the leg  141 B must be set so that the foot  142 B is connectable to the bottom surface  8 . A width of the leg  141 B is set so that it provides the foot  142 B with rigidity to some extent so as to prevent the foot  142 B from easily deforming in pulling off.  
         [0074]    The tips  144   b  of the feet  142 B must be located outside the projections  134 , similar to FIG. 1. An angle θ 3 , at which the foot  142 B extends, corresponds functionally to the angle θ 2  shown in FIG. 1, and a description will be omitted. The foot  142 B shown in FIG. 10 has an arc shape having a central angle of 120°, but may have a shape of an ellipse, quadratic curve, and other curves, a V-shape, and other shapes.  
         [0075]    A description will now be given of a network device  200  as an inventive electronic apparatus with reference to FIGS.  11  to  15 . Here, FIG. 11 is a perspective overview of the network device  200 . FIG. 12 is a view showing a plug in unit (“PIU”) structure  210 . FIG. 13 is a perspective overview showing the PIU  210  that is being removed from the network device  200 .  
         [0076]    As shown in FIG. 11, the network device  200  is a rack- or shelf-shaped communication controller that removably accommodates plural PIUs  210  of the same type or different types. In the instant embodiment, the network device  200  can accommodate seven PIUs  210 , but the number is exemplary. FIG. 11 assigns the same reference numeral to different types of PIUs for convenience.  
         [0077]    [0077]FIG. 12 is a view showing a certain type of PIU  210  that has a LAN connector  220 . FIG. 12A is a bottom view of an eject mechanism  240  of the PIU  210 . FIG. 12B is a front view of the PIU  210 . FIG. 12C is a plane view of the PIU  210 . FIG. 12D is a side view of FIG. 12C.  
         [0078]    The PIU  210  shown in FIG. 12 accommodates a printed circuit board (not shown) in a housing  212 , and includes various connectors  220  to  224 , a guide module  230 , and an eject mechanism  240 , and a shield gasket  250 .  
         [0079]    The connector  220  is a LAN connector connected to an external terminal, and there are plural connectors in the PIU shown in FIG. 12. Each LAN connector  220  is connected to a communication terminal that communicates on the network, such as a personal computer (“PC”) and a hub, for example, via a UTP cable (not shown). The connector  222  is a connector connected to the network device  200 . The connector  224  serves as a connector for power supply. The guide module  230  serves to guide insertion and ejection of the PIU  210 , may apply any structure known in the art, and a detailed description thereof will be omitted.  
         [0080]    The eject mechanism  240  serves to eject the PU  210  from the network device  200 , and includes a pair of L-shaped card ejectors  242 , and tabs  242  provided onto them. A user pulls the tubs  244  in a direction F shown in FIG. 12A using his/her thumb, and ejects the PIU  210  from the network device  200 . The elect mechanism  240  may use any structure known in the art, and a description thereof will be omitted.  
         [0081]    The PIU  210  further includes a shield gasket  250 , as shown in FIGS. 12C and 12D. The gasket  250  is provided at both sides to shields right and left sides of the PIU  210 . The shield gasket  250  may apply the gasket  100 , thereby preventing leakages of electromagnetic waves and noises from the printed circuit board outside the PIU  210 .  
         [0082]    [0082]FIG. 13 is a perspective overview showing the PIU  210  that is being partially removed from the network device  200 . FIG. 14 is an enlarged perspective view of part A shown in FIG. 13. As shown in FIG. 14, the network device  200  includes therein a shield gasket  270 . The shield gasket  270  may apply gasket  100 , thereby preventing leakages of electromagnetic waves and noises from the printed circuit board (not shown) outside the network device  200 .  
         [0083]    [0083]FIG. 15A is a front view of the three-layer PIU  210  accommodated in the network device  200  shown in FIG. 11. FIG. 15B is a side view of part  260  that contacts the gasket  270  shown in FIG. 13 at the side of the PIU  210 . FIG. 15C is a view showing part of the upper PIU  210  in a view corresponding to FIG. 12A, which contacts the gasket  250  of the lower PIU  210 , and bevel part S 3  indicates a contact portion.  
         [0084]    A contact between a spring of the connector  220  and a front-plate square hole shield the connector  220  as shown in an arrow S 1  in FIG. 15A, and a contact with a gasket of the next PIU  210  maintains an electromagnetic shield. As discussed above, the cotton  190  is so elastic that the gasket does not get damaged even when the upper PIU  210  contacts or moves on the conductive cloth  192 .  
         [0085]    According to the network device  200  that utilizes the inventive gaskets  250  and  270 , electronic waves generated from the network device  200  and the PIU  210  can be prevented from leaking.  
         [0086]    Further, the present invention is not limited to these preferred embodiments, and various variations and modifications may be made without departing from the spirit and scope thereof. For example, an electronic apparatus applicable to the present invention is not limited to network devices.  
         [0087]    Thus, the present invention may provide a gasket that is structurally easily mounted onto and hard to come off from an electronic apparatus, and the electronic apparatus having the gasket.