Patent Publication Number: US-7721894-B2

Title: Shock-absorbing packing material, and shock-absorbing packing material for television receiver

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on Japanese Patent Application No. 2007-029513 filed on Feb. 8, 2007, the contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a shock-absorbing packing material which is put in a gap between an electronic device such as a television receiver and a cardboard box when the electronic device is packed in the cardboard box. 
     2. Description of Related Art 
     A television receiver, which is also hereinafter referred to as “TV receiver” for short, is packed in a cardboard box at the time of factory shipment. In packing a TV receiver in a cardboard box, a shock-absorbing packing material is put in a gap between the cardboard box and the TV receiver. The shock-absorbing packing material is a foamed resin molding, and specifically a member which absorbs a physical shock to prevent the shock from reaching the TV receiver when the cardboard box with the TV receiver packed therein receives the shock owing to e.g. drop of the cardboard box or collision with other object. 
       FIG. 10  is a front-side sectional view showing the condition where a TV receiver is packed in a cardboard box, which is known in the art.  FIG. 11  is a lateral sectional view of the cardboard box with the TV receiver packed therein as shown in  FIG. 10 .  FIG. 12  is a perspective view of a shock-absorbing packing material conventionally used for a TV receiver. As shown in  FIGS. 10 and 11 , a TV receiver  3  is packed in a cardboard box  1 , and each shock-absorbing packing material formed from a foamed resin molding is arranged in contact with adjacent four faces of the cardboard box  1 . Now, in the description below, a corner portion formed by butting different exterior faces on each other is termed “an exterior ridgeline”, a corner portion formed by butting different interior faces on each other is termed “an interior ridgeline”, a point where different exterior ridgelines gather is termed “an exterior apex”, and a point where different interior ridgelines gather is termed “an interior apex”. 
     Shock-absorbing packing materials  92   b  arranged against a lower portion of the TV receiver  3  is disposed so as to support the lower portion of the TV receiver  3  from left and right sides thereof. Shock-absorbing packing materials  92   a  and  92   c  arranged against an upper portion of the TV receiver  3  are disposed so as to support the upper portion of the TV receiver from front and rear sides thereof. 
     The shock-absorbing packing material  92   a  shown in  FIG. 12  is arranged so as to support the exterior ridgeline of the front side of the upper portion of the TV receiver. However, the shock-absorbing packing materials  92   b  and  92   c  arranged in the other places have a similar shape. As shown in  FIG. 12 , the shock-absorbing packing material  92   a  has: a first wall  921  which is an elongated member; a second wall  922  having the same length as the first wall  921  has; and a pair of third walls  923  provided integrally with the first wall  921  and the second wall  922  at right angles with respect to the lengthwise directions of the first and second walls. The first wall  921  and second wall  922  are joined with their ends abutting against each other so that they coincide in lengthwise direction with each other. 
     When the TV receiver  3  is packed in the cardboard box  1 , the shock-absorbing packing material  92   a  is disposed so that the interior ridgeline formed by the interior face of the first wall  921  and the interior face of the second wall  922  abuts against a corner ridge portion of the TV receiver  3  on the front side of the upper portion thereof. In addition, the paired third walls  923  are disposed with their interior faces abutting against two opposing side faces of the TV receiver  3 . Likewise, the corner ridge portion located on the rear side of the upper portion of the TV receiver  3 , and left and right corner ridge portions of the lower portion of the TV receiver are held by the shock-absorbing packing materials  92   b  and  92   c  (see  FIGS. 10 and 11 ). Because of such arrangement that the TV receiver  3  is arranged in the cardboard box  1  with shock-absorbing packing materials  92   a ,  92   b  and  92   c  put therebetween, physical shocks owing to drop of the cardboard box  1  and collision with other object never reach the TV receiver. 
     Meanwhile, a TV receiver is often out of balance in weight on the whole depending on the shapes and layout of members and constituents arranged therein, which include a CRT (Cathode Ray Tube) and a power supply device, etc. In many TV receivers, they are heavier on the front side where an image-display portion of CRT is located compared to the other sides. When a cardboard box in which a TV receiver heavier on its front side as such is packed drops from an elevation, a corner ridge portion or an apex portion of the front side of the cardboard box will come into contact with the face of the floor first. 
     Hence, drop tests in which actual dropping conditions of a cardboard box with a TV receiver  3  packed therein are duplicated have been carried out.  FIG. 13  is an illustration for explanation of such drop tests. The indications of front and bottom faces in  FIG. 13  represent the faces which the front and bottom faces of the TV receiver  3  front on. 
     As described above, the TV receiver  3  is out of balance in weight on the whole. Therefore, in the first test, the cardboard box is dropped so that an apex formed by its front, upper and side faces comes into contact with the face of the floor first, as shown in  FIG. 13 . After that, in the second test, the cardboard box is dropped so that a ridgeline formed by the front face and upper face comes into contact with the face of the floor first. In this test, the exterior face of the first wall  921  of the shock-absorbing packing material  92   a  abuts against the upper face of the cardboard box  1 , the exterior face of the second wall  922  abuts against the front face, and the exterior faces of the paired third walls  923  abut against the two side faces. 
       FIG. 14  is a sectional view showing the result of the drop test. After the first test, in the shock-absorbing packing material  92   a , a crack Cr arose extending from the following three ridgelines: i.e. the interior ridgeline formed by interior faces of the first wall  921  and the second wall  922 ; the interior ridgeline formed by interior faces of the second wall  922  and the third wall  923 ; and the interior ridgeline formed by interior faces of the third wall  923  and the first wall  921  located near the apex that reached the floor face first. 
     As shown in  FIG. 14 , formed was a crack Cr running from the interior ridgeline formed by the first wall  921  and the second wall  922  of the shock-absorbing packing material  92   a  to the exterior ridgeline formed by the first wall  921  and the second wall  922 , i.e. a crack Cr running at an angle of 45 degrees with respect to the faces of the first wall  921  and the second wall  922  against which the TV receiver  3  abutted. The shock-absorbing packing material  92   a  with the crack Cr thus formed was used to execute the second test. Then, the cardboard box received a shock owing to the weight of the TV receiver  3  which widened the crack Cr of the shock-absorbing packing material  92   a , namely a shock enough to jam the corner ridge portion of the TV receiver  3  into the crack Cr. Consequently, the crack Cr of the shock-absorbing packing material  92   a  reached the exterior ridgeline, and the TV receiver  3  ended up as crashing into the face of the floor and being fractured. 
     To avoid the transmission of a physical shock to the TV receiver  3  in the two tests, it is sufficient to make larger the thickness of the shock-absorbing packing material, thereby to enhance the shock-absorbing ability of the shock-absorbing packing material  92   a . However, the increase in the thickness of the shock-absorbing packing material  92   a  boosts the amount of the foamed resin used to form the shock-absorbing packing material  92   a  and therefore raises the cost. In addition, the increase in the thickness of the shock-absorbing packing material  92   a  makes larger outer dimensions of the cardboard box  1 . Such increase of the outer dimensions decreases the number of cardboard boxes which can be loaded in a container used for shipment of TV receivers  3 , resulting in the increase in the transportation cost. 
     Under these circumstances, a method for reducing the fracture of the shock-absorbing packing material owing to the shock by drop has been proposed. For instance, JP-UM-A-58-65268 discloses a device in which relief portions having the shape of a groove are provided in two faces forming a ridgeline in order to disperse a stress produced in a corner portion at the time of drop, and in the other face, i.e. the remaining one of three faces forming the ridge corner of interest, a relief portion is provided diagonally with respect to the ridge corner. According to the device, the stress arising at the time of drop can be dispersed. 
     Also, JP-UM-A-61-77372 discloses a device in which a reentrant portion is provided in a corner portion to control the force caused by a physical shock, whereby a fracture is minimized. 
     Further, in the device disclosed by Japanese Utility Model Registration No. 3,072,574, a gap is formed between a corner portion of a shock-absorbing material and a corner portion of a TV receiver, thereby preventing direct transmission of the force caused by a physical shock to the TV receiver. 
     However, the device disclosed by JP-UM-A-58-65268 is based only on the assumption that a corner ridge portion comes into contact with a floor first, i.e. only the condition where the second test as shown in  FIG. 13  is executed is assumed therein. In reality, it is conceivable that the force is applied all the three corner ridge portions as assumed in the first test. In such case, the stress can be concentrated on a corner ridge portion where no relief portion is formed. 
     Also, while in the device disclosed by JP-UM-A-61-77372, a reentrant portion is provided in a corner portion to control the force caused by a physical shock, the reentrant portion for controlling such force has a complicated form, and needs labor and time for manufacturing. In addition, with the device, a corner portion of a cardboard box is squashed thereby to reduce the first shock for the purpose of dispersing the force caused by a physical shock. Therefore, when drop of the cardboard box (the second test) is executed so that the corner ridge portion reaches a floor first after the first drop of the corner portion (the first test), the effect of the reentrant portion cannot be expected. 
     Moreover, with the device disclosed by Japanese Utility Model Registration No. 3,072,574, the transmission of the force caused by a physical shock from the shock-absorbing material to the TV receiver is delayed thereby to consume the energy when the shock-absorbing material is deformed, and thus the force caused by a physical shock is weakened. However, when the shock-absorbing material receives a physical shock such that the shock-absorbing material is fractured, the shock will be transmitted to the TV receiver. 
     SUMMARY OF THE INVENTION 
     Therefore, it is an object of the invention to provide a shock-absorbing packing material which can avoid direct contact of a TV receiver with a floor even when a cardboard box with the TV receiver packed therein is dropped so that a corner portion or corner ridge portion reaches the floor first. 
     A shock-absorbing packing material according to an embodiment of the invention is intended to abut against a corner ridge portion of an electronic device and lessen a physical shock to the electronic device when the electronic device is packed in a cardboard box, and includes: an elongated main body portion having an L-like shape in section and including a first wall and a second wall orthogonal to the first wall; and a pair of third walls joined to the first wall and the second wall at two opposite ends of a lengthwise direction of the main body portion orthogonally to the first wall and the second wall, and integrated with the main body portion. The first wall has: a pair of first grooves each having a well-like shape in section formed in a portion of an interior wall face of the first wall in connection with an interior wall face of the second wall, the pair of first grooves extending along the lengthwise direction; and a pair of second grooves each having a well-like shape in section formed in a portion of the interior wall face of the first wall in connection with an interior wall face of the corresponding one of the pair of third walls, in which each second groove is joined to the corresponding first groove and extends orthogonally to the first groove. The second wall has a pair of third grooves formed in its exterior wall face; the paired third grooves each extend in a direction orthogonal to an exterior wall face of the first wall. 
     According to the above configuration, under the condition where a crack formed in a corner ridge portion of the shock-absorbing packing material after the first test, in which the test package is dropped with a corner portion thereof kept down, extends from the corner ridge portion toward one of the faces forming the corner ridge portion, even when the second test is carried out, in which the test package is dropped with the corner ridge portion including the corner portion of interest kept down, the TV receiver never crashes into the floor because of the buffering effect of the shock-absorbing packing material. 
     In the shock-absorbing packing material according to the preferred embodiment of the invention, each of the pair of third grooves has: a first interior face perpendicular to the exterior wall face of the second wall; and a second interior face in parallel to the first interior face, but closer to a center of the main body portion in a longitudinal direction thereof and shallower than the first interior face. In addition, the first interior face is arranged so as to flush with the interior wall face of the third wall. 
     A shock-absorbing packing material for a TV receiver according to another embodiment of the invention is intended for lessening a physical shock to a TV receiver with a CRT (Cathode Ray Tube), which abuts against a corner ridge portion of the TV receiver and lessens the shock when the TV receiver is packed in a cardboard box. The shock-absorbing packing material is composed of a foamed resin molding, and includes: an elongated main body portion having an L-like shape in section and including a first wall and a second wall orthogonal to the first wall; and a pair of third walls joined to the first wall and the second wall at two opposite ends of a lengthwise direction of the main body portion orthogonally to the first wall and the second wall, and integrated with the main body portion. The first wall has: a pair of first grooves each having a well-like shape in section formed in a portion of an interior wall face of the first wall in connection with an interior wall face of the second wall, the pair of first grooves extending along the lengthwise direction; and a pair of second grooves each having a well-like shape in section formed in a portion of the interior wall face of the first wall in connection with an interior wall face of the corresponding one of the pair of third walls, in which each second groove is joined to the corresponding first groove and extends orthogonally to the first groove. The second wall has a pair of third grooves formed in its exterior wall face. The paired third grooves extend from a plane at a distance of 25 millimeters from and in parallel with the interior wall face of the first wall in a direction orthogonal to the lengthwise direction of the main body portion and opposite to the first wall. Further, each of the pair of third grooves has: a first interior face perpendicular to the exterior wall face of the second wall; a second interior face in parallel to the first interior face, but closer to a center of the main body portion in a longitudinal direction thereof and shallower than the first interior face; and a third bottom face joining between the first and second interior faces. Furthermore, the first interior face is arranged so as to flush with the interior wall face of the third wall. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front-side sectional view showing a condition where a set of shock-absorbing packing materials according to an embodiment of the invention is used to pack a TV receiver in a cardboard box; 
         FIG. 2  is a lateral sectional view of the condition where the TV receiver is packed shown by  FIG. 1 ; 
         FIG. 3  is a perspective view of the shock-absorbing packing material according to the embodiment of the invention; 
         FIG. 4  is a plan view of the shock-absorbing packing material shown in  FIG. 3 ; 
         FIG. 5  is a front view of the shock-absorbing packing material shown in  FIG. 3 ; 
         FIG. 6  is a side view of the shock-absorbing packing material shown in  FIG. 3 ; 
         FIG. 7  is a plan view of the shock-absorbing packing material after execution of the first drop test as described with reference to  FIG. 13 ; 
         FIG. 8  is a front view of the shock-absorbing packing material after execution of the first drop test as described with reference to  FIG. 13 ; 
         FIG. 9  is a side view of the shock-absorbing packing material after execution of the first drop test as described with reference to  FIG. 13 ; 
         FIG. 10  is a front-side sectional view showing the condition where a TV receiver is packed in a cardboard box according to a conventional art; 
         FIG. 11  is a lateral sectional view of the condition of the cardboard box with the TV receiver packed therein shown by  FIG. 10 ; 
         FIG. 12  is a perspective view of a conventional shock-absorbing packing material used to pack a TV receiver; 
         FIG. 13  is an illustration for explanation of drop tests including the first drop test; and 
         FIG. 14  is a sectional view showing the result of the drop test. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of the invention will be described below with reference to the drawings.  FIG. 1  is a front view showing a condition where a set of shock-absorbing packing materials according to an embodiment of the invention is used to pack a TV receiver in a cardboard box.  FIG. 2  is a side view of the condition where the TV receiver is packed shown by  FIG. 1 . As shown in  FIGS. 1 and 2 , shock-absorbing packing materials  2   b  are disposed on the bottom face of the cardboard box  1  prepared in a rectangular parallelepiped shape, on which the TV receiver  3  is placed with its two opposite side portions of the lower face side supported by the shock-absorbing packing materials  2   b  for the bottom face. Further, shock-absorbing packing materials  2  and  2   c  are disposed on the front and rear sides of the upper face of the TV receiver  3 , whereby the TV receiver  3  is disposed in the cardboard box  1  so that it is not brought out of position. 
       FIG. 3  is a perspective view of the shock-absorbing packing material according to an embodiment of the invention.  FIG. 4  is a plan view of the shock-absorbing packing material shown in  FIG. 3 .  FIG. 5  is a front view of the shock-absorbing packing material shown in  FIG. 3 .  FIG. 6  is a side view of the shock-absorbing packing material shown in  FIG. 3 . Now, it is noted that in the description below, a corner portion formed by butting different exterior faces on each other is termed “an exterior ridgeline”, a corner portion formed by butting different interior faces on each other is termed “an interior ridgeline”, a point where different exterior ridgelines gather is termed “an exterior apex”, and a point where different interior ridgelines gather is termed “an interior apex”. In addition, in the description below, the shock-absorbing packing material  2  which holds the ridgeline formed by the front and upper faces of the TV receiver  3  will be described mainly. The shock-absorbing packing material  2  is a member having a symmetric shape. While only a groove on one side thereof is shown in the drawing for the sake of convenience, the shock-absorbing packing material  2  is shaped so as to be geometrically symmetric in reality. 
     As shown in  FIGS. 3 to 6 , the shock-absorbing packing material  2  has: an elongated main body portion  20  having an L-like shape in section including a first wall  21  and a second wall  22  orthogonal to the first wall  21 ; and a pair of third walls  23  joined to the first wall  21  and the second wall  22  at two opposite ends of a lengthwise direction of the body portion of the main body portion  20  orthogonally to the first wall  21  and the second wall  22  and integrated with the main body portion. 
     Also, the shock-absorbing packing material  2  has: a first groove  41  formed in a portion of an interior face  211  of the first wall  21 , which adjoins an interior face  221  of the second wall  22 ; and a second groove  42  formed in a portion of the interior face  211  of the first wall  21 , which adjoins an interior face  231  of one of the pair of third walls  23 . Further, as shown in  FIG. 4 , the first groove  41  and the second groove  42  are formed so that they make one contiguous shape, in which the first groove  41  extends from the interior face  231  of the third wall  23  to a length of L, and the second groove  42  extends from the interior face of the second wall  22  to a length of L. 
     In the exterior face  222  of the second wall  22 , a third groove  43  is formed. The third groove  43  has: a first interior wall face  431  which is flush with the interior face  231  of the third wall  23 ; a second interior wall face  432  which is opposed to the first interior wall face  431  and extends from the exterior face  222  of the second wall  22  to a depth shallower than the depth that the first interior wall face  431  extends to; and a bottom face  433  connecting and lying between ends of the first interior wall face  431  and the second interior wall face  432 , which are the farthest, in depth, from the exterior face  222 . An interior ridgeline  434  formed by the bottom face  433  and the first interior wall face  431  is in parallel with an interior ridgeline  241  formed by the interior face  221  of the second wall  22  and the interior face  231  of the third wall  23 , and is located nearer to the interior ridgeline  241  in comparison to other portions of the third groove  43 . Moreover, as shown in  FIGS. 5 and 6 , the third groove  43  is formed so as to extend from a place at a distance of L 2  from the interior face of the first wall  21  in parallel with an exterior ridgeline  251  formed by the second wall  22  and the third wall  23 . 
     The shock-absorbing packing material  2  with the first groove  41 , the second groove  42  and the third groove  43  formed therein is used to pack the TV receiver  3  in the cardboard box  1 , and then one of the drop tests as shown in  FIG. 13 , namely the first drop test was carried out. In the first drop test, the cardboard box  1  was dropped so that the apex formed by the upper, front and side faces thereof came into contact with the face of the floor first. Then, the shock-absorbing packing material  2  packed in the cardboard box  1  received a shock in a direction from an exterior apex formed by the first wall  21  and the second wall  22  and one of the pair of third walls  23  toward the interior apex. 
       FIG. 7  is a plan view of the shock-absorbing packing material after execution of the first drop test as described with reference to  FIG. 13 .  FIG. 8  is a front view of the shock-absorbing packing material after execution of the first drop test as described with reference to  FIG. 13 .  FIG. 9  is a partial side view of the shock-absorbing packing material after execution of the first drop test as described with reference to  FIG. 13 . 
     As shown in  FIG. 7 , after the first drop test, a crack C 1  was formed, which was likely to join between the interior ridgeline  434  of the third groove  43  and the interior ridgeline  241  formed by the interior face  221  of the second wall  22  and the interior face  231  of the third wall  23 . The crack had a form extending within the limits of the second wall  22 . This implies that at the time of drop, the stresses concentrated on the interior ridgeline  434  of the third groove  43  and the interior ridgeline  241  formed by the second wall  22  and third wall  23 . 
     Further, as shown in  FIGS. 8 and 9 , a crack C 2  was formed extending from an end portion face  420  of the bottom of the second groove  42  toward the exterior face  212  of the first wall  21 , and a crack C 3  was made running from an end portion face  410  of the bottom of the first groove  41  toward the exterior face  212 . It is conceivable that the cracks C 2  and C 3  were formed by the stresses concentrating on the first groove  41  and the second groove  42 . Also, it can be conceived that as the crack C 1  formed on the third groove  43  released the energy for the crack C 3  opened in the bottom end portion face  410  of the first groove  41  to extend inclining toward the side of the second wall  22 , the crack C 3  extended in the first wall  21  without inclining toward the side of the second wall  22 . Likewise, it can be conceived that the crack C 2  opened in the bottom end portion face  420  of the second groove  42  extended in the first wall  21  without inclining toward the side of the third wall  23 . 
     Still further, it can be conceived in this case that the third groove  43  was spaced, by the distance of L 2 , apart from the plane including the interior face  211  of the first wall  21  as shown in  FIGS. 5 and 6 , which produced the following effect. That is, the shock-absorbing packing material  2  could be prevented from being smashed into fragments near and in the corner portion, which had come into contact with the face of the floor first in the first drop test, owing to the stress (energy) excessively concentrated on the corner portion. 
     In the second drop test, the shock-absorbing packing material  2  with the cracks C 1 , C 2  and C 3  formed therein as shown in  FIGS. 7 to 9  was used as it was. As shown in  FIG. 13 , the cardboard box  1  was dropped with the corner ridge portion formed by the front and upper faces down. When dropped, the shock-absorbing packing material  2  received a shock in the direction from the exterior ridgeline toward the interior ridgeline formed by the first wall  21  and the second wall  22 . 
     The crack C 3  running from the bottom end portion face  410  of the first groove  41  reached the exterior face  212  of the first wall  21  as shown in  FIG. 9 . However, no crack was formed in the direction in which the shock is applied. As the portion of the shock-absorbing packing material  2  joining between the first wall  21  and the second wall  22  absorbs the shock as applied in the second test, it is possible to avoid that the corner ridge portion of the TV receiver  3  is directly smashed against the floor and thus the TV receiver  3  is fractured. 
     While the embodiment of the invention has been described above specifically, the invention is not limited to the embodiment. Various changes and modifications may be made without departing from the subject matter hereof. 
     The invention is applicable to a shock-absorbing packing material which can lessen a physical shock in the situation where it is packed in a cardboard box together with a TV receiver in transporting the TV receiver.