Patent Publication Number: US-8120896-B2

Title: Strap device and electronic apparatus including the same

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a strap device used in a state of being attached to an electronic apparatus such as a notebook personal computer (PC) or a personal digital assistant (PDA) as an object, and an electronic apparatus including the strap device. 
     2. Description of Related Art 
     Electronic apparatuses with excellent portability, such as a notebook PC and a PDA, have been used commonly in recent years, and many of them are equipped with a strap device in order to improve their portability (see Patent documents 1 and 2, for example). 
     Patent document 1 discloses a notebook PC equipped with a holding portion (hand strap), such as a fixing belt for fixing a hand for holding the notebook PC body, on its undersurface (back). According to the configuration disclosed in Patent document 1, the notebook PC can be operated with a right hand while holding the notebook PC body with the palm of a left hand placed through the hand strap. It should be noted that, in this case, the hand strap is attached to the notebook PC along a longitudinal direction of a display portion (display) or a key input portion (keyboard) of the notebook PC. 
     Patent document 2 discloses a notebook PC having the configuration of Patent document 1, whose hand strap can be adjusted in accordance with the size of a user&#39;s hand.
     Patent document 1: JP 2000-105630 A (claim 3, FIGS. 1 to 3)   Patent document 2: JP 2007-102532 A (claims 1 and 2, FIG. 1)   

     SUMMARY OF THE INVENTION 
     In Patent documents 1 and 2, however, each of the hand straps is attached to the notebook PC along the longitudinal direction of the display portion or the key input portion. Thus, the visual direction of the display portion and the layout direction of input keys of the key input portion of the notebook PC become orthogonal to the direction of the fingers of the hand placed through the hand strap, thereby resulting in poor visibility of the display portion and poor operability of the key input portion and the touch panel. That is, when the notebook PC body is held normally, the visible direction of the display portion and the layout direction of input keys of the key input portion tilt. Thus, in actual use, the notebook PC body needs to be tilted with the wrist in order to improve the visibility of the display portion and the operability of the key input portion and the touch panel, which leads to wrist fatigue. 
     With the foregoing in mind, it is an object of the present invention to provide a strap device capable of, when used in a state of being attached to an electronic apparatus body including a display portion and a key input portion as an object, improving the visibility of the display portion and the operability of the key input portion and the touch panel without tilting the electronic apparatus with the wrist; and an electronic apparatus equipped with the strap device. 
     In order to attain the above object, the strap device of the present invention includes a substantially plate-shaped belt base to be attached to an object; and a strap belt formed in an annular shape and supported by a substantially center portion of the belt base rotatably within a plane substantially parallel to the belt base. 
     According to the configuration of the strap device, the annular strap belt, through which the palm of a hand is placed, is supported rotatably by the substantially center portion of the belt base attached to the object within a plane substantially parallel to the belt base. Thus, when the strap device is used in a state of being attached to an electronic apparatus body including a display portion and a key input portion as the object, the visibility of the display portion and the operability of the key input portion and the touch panel can be improved by rotating the electronic apparatus body without having to tilt the electronic apparatus body with the wrist. As a result, the wrist does not get tired even if the electronic apparatus body is used for long hours. Further, since the strap belt can be rotated clockwise and counterclockwise with respect to the belt base (object), both a right-handed user and a left-handed user can obtain similar effects by using the strap device. 
     In the configuration of the strap device of the present invention, it is preferable that the strap belt projects beyond each of opposing left and right outer edges of the belt base, and a notch is formed on at least either of upper and lower outer edges of the base belt coupling the left and the right outer edges from which the strap belt projects. According to this preferred example, it is possible to allow the rotation movement of the strap belt with respect to the belt base. Further, when the strap device is used in a state of being attached to an electronic apparatus body as an object provided with a camera or the like on its backside, it is possible to prevent the camera or the like from being hidden by the belt base. In this case, it is preferable that a concave notch is formed on each of the left and the right outer edges of the belt base. According to this preferred example, the rotation movement of the strap belt with respect to the belt base can be allowed while the strap belt can be downsized. 
     Further, in the configuration of the strap device of the present invention, it is preferable that the belt base is composed of a back part provided with a bearing member for supporting the strap belt rotatably, and a front part facing the back part, the strap belt striding over the belt base from the front part to the back part. According to this preferred example, since a part of the annular strap belt positioned on the back side of the belt base is pressed by the belt base when the strap device is attached to the object, the shape of the strap belt can be stabilized. Further, in this case, it is preferable that a protrusion, which protrudes toward the strap belt side, is provided at a substantially center portion of the front part of the belt base. In this case, it is further preferable that the protrusion is rounded. According to these preferred examples, when the electronic apparatus body as the object is held with the palm by placing the palm into the strap belt, the protrusion fits into the dinted portion of the palm, thereby allowing a user to hold the electronic apparatus body easily without exerting extra force. Thus, the electronic apparatus body can be used comfortably. 
     Further, in the configuration of the strap device of the present invention, it is preferable that each corner portion of the outer edges of the belt base is provided with an attachment member for attaching the belt base to the object. In this case, it is preferable that the attachment members provided at at least either a pair of upper left and upper right corner portions or a pair of lower left and lower right corner portions are attachable to and detachable from the object. According to these preferred examples, when the strap device is used in a state of being attached to, for example, an electronic apparatus body as an object that has on its back side battery packs including lids that can be removed when replacing batteries, the batteries can be replaced easily by detaching either the pair of upper left and upper right corner portions or the pair of lower left and lower right corner portions from the electronic apparatus body. 
     The electronic apparatus of the present invention includes: an electronic apparatus body including a first enclosure including a control portion for controlling a display signal to be displayed on a display portion, a circuit board equipped with a signal processing circuit for processing an input signal received from the control portion and/or a display signal to be displayed on the display portion, and a second enclosure containing the circuit board and forming a housing together with the first enclosure; and the strap device according to the present invention attached to the second enclosure. Here, the “control portion” is a concept that includes a key input portion for inputting an information signal to be converted into a display signal, scroll buttons for controlling the location, the size, and the like of a region of the display portion in which a display signal is displayed, operation buttons for changing or identifying a location within the display portion in which keys are entered, and the like. 
     According to the configuration of the electronic apparatus of the present invention, it is possible to obtain not only the effects as described above such as improving the visibility of the display portion and the operability of the key input portion and the touch panel, but also the following effects. That is, as described above, since the electronic apparatus of the present invention is easy to hold and has excellent operability, it is possible to reduce the chances of the electronic apparatus body held with the palm placed through the strap belt being dropped. Consequently, it is possible to reduce breakdown of the electronic apparatus body or to reduce the chances of the user himself or people in the surroundings being injured as a result of dropping the electronic apparatus body. Furthermore, a notebook PC body as an electronic apparatus body is designed generally on the basis of the premise that it is operated while being placed on a table or the like. Thus, the notebook PC body is configured such that heat generated therein is radiated from its back side, which faces the table or the like. Thus, when the notebook PC body is operated with one hand by attaching the strap device to the notebook PC and holding the notebook PC body with the other hand, it is possible to reduce transfer of the heat generated in the notebook PC body to the palm of the hand holding the notebook PC since the belt base is provided between the palm holding the notebook PC body and the back of the notebook PC body. 
     Further, in the configuration of the electronic apparatus of the present invention, it is preferable that the display portion and the control portion are provided in the same plane of the first enclosure. 
     According to the present invention, it is possible to provide a strap device capable of, when used in a state of being attached to an electronic apparatus body including a display portion and a key input portion as the object, improving the visibility of the display portion and the operability of the key input portion and the touch panel without tilting the electronic apparatus body with the wrist; and an electronic apparatus equipped with the strap device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view showing a strap device according to Embodiment 1 of the present invention. 
         FIG. 2  is a back view showing the strap device according to Embodiment 1 of the present invention. 
         FIG. 3  is a perspective view showing a condition of use of a notebook PC equipped with the strap device according to Embodiment 1 of the present invention from the back side. 
         FIG. 4  is a front view showing a strap device according to Embodiment 2 of the present invention. 
         FIG. 5  is a back view showing the strap device according to Embodiment 2 of the present invention. 
         FIG. 6  is a cross-sectional view along the IV-IV line in  FIG. 4 . 
         FIG. 7  is a front view showing the strap device according to Embodiment 2 of the present invention in a state where a strap belt is open. 
         FIG. 8  is a front view showing the strap device according to Embodiment 2 of the present invention for describing how to adjust the length of the strap belt. 
         FIG. 9  is a front view showing the strap device according to Embodiment 2 of the present invention attached to the back of an electronic apparatus body. 
         FIG. 10  is a front view showing a condition of use of the electronic apparatus body equipped with the strap device according to Embodiment 2 of the present invention. 
         FIG. 11  is a perspective view showing the front of the electronic apparatus body according to Embodiment 2 of the present invention. 
         FIG. 12  is a perspective view showing the back of the electronic apparatus body according to Embodiment 2 of the present invention. 
         FIG. 13  is an enlarged perspective view showing the portion A shown in  FIG. 12 . 
     
    
    
     DESCRIPTION OF THE INVENTION 
     Hereinafter, the present invention will be described in detail by way of illustrative embodiments with reference to the drawings. 
     Embodiment 1 
     The strap device of the present invention is used in a state of being attached to an electronic apparatus body, such as a notebook PC or a PDA. First, a strap device used in a state of being attached to a notebook PC as an electronic apparatus body will be described. 
     Strap Device 
       FIG. 1  is a front view showing a strap device according to Embodiment 1 of the present invention.  FIG. 2  is a back view showing the strap device according to Embodiment 1 of the present invention.  FIG. 3  is a perspective view showing a condition of use of a notebook PC body equipped with the strap device according to Embodiment 1 of the present invention from the back side. 
     As shown in  FIGS. 1 and 2 , a strap device  25  according to the present embodiment includes: a belt base  26  formed in a substantially rectangular and plate shape, which is to be attached to an object; and a strap belt  27  formed in an annular shape and supported by a substantially center portion of the belt base  26  rotatably within a plane substantially parallel to the belt base  26 . Here, the belt base  26  is composed of a back part provided with a pivot fitting  28  as a bearing member for supporting the strap belt  27  rotatably, and a front part facing the back part. The strap belt  27  extends across the belt base  26  from the front part to the back part of the belt base  26 . Since the strap device  25  has such a configuration, a part of the annular strap belt  27  positioned on the back part side of the belt base  26  is pressed by the belt base  26  when the strap device  25  is attached to the back of a notebook PC body  29  as an object (see  FIG. 3 ), and the shape of the strap belt  27  can be stabilized. The strap belt  27  can be rotated about plus or minus 20° from the state shown in  FIG. 1  (see arrows D and E in  FIG. 1 ). 
     Further, the strap belt  27  projects beyond each of opposing left and right outer edges of the belt base  26 , thereby allowing the rotation movement of the strap belt  27  with respect to the belt base  26 . It should be noted that the size of the strap belt  27  can be changed in accordance with the size of a user&#39;s hand (see descriptions in Embodiment 2). 
     A protrusion  30 , which protrudes toward the strap belt  27  side, is provided at a substantially center portion of the front part of the belt base  26 . Thus, when holding the notebook PC body  29  as an object with a palm by placing the palm into the strap belt  27  (see  FIG. 3 ), heat radiated from the back of the notebook PC body  29  is less likely to transfer to the palm. It is preferable that the protrusion  30  is rounded. 
     The belt base  26  is provided with screw insertion holes  31  as attachment members at a pair of lower left and lower right corner portions. Thus, the strap device  25  can be attached to the back of the notebook PC body  29  by placing the screw insertion holes  31  of the belt base  26  over screw holes (not shown) at a pair of lower left and lower right corner portions of the back of the notebook PC body  29 , and fixing the strap device  25  to the notebook PC body  29  with screws  32  (see  FIG. 3 ). Further, the belt base  26  is provided with male hooks  33  as attachment members at a pair of upper left and upper right corner portions of the back part. Thus, when attaching the strap device  25  to the back of the notebook PC body  29 , the male hooks  33  of the belt base  26  can be latched to female hooks (not shown) provided respectively at a pair of upper left and upper right corner portions of the back of the notebook PC body  29  (see  FIG. 3 ). A battery of the notebook PC body  29  is placed on the upper side of the keyboard. By configuring the attachment members provided at the pair of upper left and upper right corner portions of the belt base  26  to be attachable to and detachable from the notebook PC body  29 , the battery of the notebook PC body  29  can be replaced easily by detaching the pair of upper left and upper right corner portions of the belt base  26  from the notebook PC body  29 . 
     The Use of the Strap Device and the Electronic Apparatus Body Equipped with the Strap Device 
     Next, the use of the strap device and the electronic apparatus body equipped with the strap device according to the present embodiment will be described. 
     As shown in  FIG. 3 , the notebook PC body  29  includes: a first front-side enclosure  34  including a control portion for controlling a display signal to be displayed on a liquid crystal (LC) display portion; a circuit board (not shown) equipped with a signal processing circuit for processing an input signal received from the control portion and/or a display signal to be displayed on the liquid crystal display portion; and a second back-side enclosure  35  containing the circuit board and forming a housing together with the first enclosure  34 . Here, the “control portion” includes a key input portion for inputting an information signal to be converted into a display signal, scroll buttons for controlling the location, the size, and the like of a region of the liquid crystal display portion in which a display signal is displayed, operation buttons for changing or identifying a location within the liquid crystal display portion in which keys are entered, and the like. 
     The strap device  25  according to the present embodiment is used in a state of being attached to the back side of the notebook PC body  29  as an electronic apparatus body. The strap device  25  may be attached to the notebook PC body  29  as follows. First, the screw insertion holes  31  at the pair of lower left and lower right corner portions of the belt base  26  are placed over the screw holes on the pair of lower left and lower right corner portions of the back of the notebook PC body  29  and the strap device  25  is fixed to the notebook PC body  29  with the screws  32 . Next, the male hooks  33  at the pair of upper left and upper right corner portions of the belt base  26  are latched to the female hooks on the pair of upper left and upper right corner portions of the back of the notebook PC body  29 . After attaching the strap device  25  to the notebook PC body  29  in the above manner, the palm of the left hand is placed through the strap belt  27 , so that the notebook PC body  29  is held with the palm of the left hand while key operation is performed with the right hand. In this case, since the strap belt  27 , through which the palm of the left hand is placed, is supported by the substantially center portion of the belt base  26  attached to the notebook PC body  29  rotatably within a plane substantially parallel to the belt base  26 , the visibility of the display portion (display) and the operability of the key input portion (keyboard) can be improved by rotating the notebook PC body  29  without having to tilt the notebook PC body  29  with the wrist. As a result, even if the notebook PC body  29  is used for long hours by holding it with the left hand, the wrist does not get tired. Further, since the strap belt  27  can be rotated clockwise and counterclockwise with respect to the belt base  26  (the notebook PC body  29 ), both a right-handed user and a left-handed user can obtain similar effects by using the strap device  25 . Furthermore, the notebook PC body  29  is designed generally on the premise that it is operated while being placed on a table or the like. Thus, the notebook PC body  29  is configured such that heat generated therein is radiated from its back side, which faces the table or the like. Thus, when the notebook body PC  29  is operated with one hand by attaching the strap device  25  to the notebook PC body  29  and holding the notebook PC body  29  with the other hand, it is possible to reduce by the belt base  26  transfer of the heat generated in the notebook PC body  29  to the palm through the back of the notebook PC body  29 . The transfer of the heat to the palm can be reduced further by providing the protrusion  30  on the belt base  26 . 
     In the strap device  25  according to the present embodiment, the protrusion  30 , which protrudes toward the strap belt  27  side, is provided at the substantially center portion of the front part of the belt base  26 . However, the protrusion  30  is not an absolute necessity. 
     Further, in the strap device  25  according to the present embodiment, the belt base  26  is composed of the back part provided with the pivot fitting  28  as a bearing member for supporting the strap belt  27  rotatably; and the front part facing the back part, and the strap belt  27  extends across the belt base  26  from the front part to the back part of the belt base  26 . However, the strap device  25  is not necessarily limited to such a configuration. For example, the annular strap belt may be placed on the front side of the belt base and may be supported by the front side of the belt base. 
     Further, in the strap device  25  according to the present embodiment, only the attachment members on the pair of upper left and upper right corner portions of the belt base  26  are attachable to and detachable from the object (the notebook PC body  29 ). It is useful for the attachment members on at least either the pair of upper left and upper right corner portions or the pair of lower left and lower right corner portions of the belt base to be attachable to and detachable from the object. However, when battery replacement or the like is not needed, none of the attachment members on the corner portions of the belt may need to be attachable to and detachable from the object. 
     Embodiment 2 
     Electronic Apparatus Body 
     A strap device according to the present embodiment is used in a state of being attached to, in particular, a PDA-type electronic apparatus body. First, an example of a PDA-type electronic apparatus body will be described. 
       FIG. 11  is a perspective view showing the front side of the electronic apparatus body according to Embodiment 2 of the present invention.  FIG. 12  is a perspective view showing the back side of the electronic apparatus body according to Embodiment 2 of the present invention.  FIG. 13  is an enlarged perspective view showing the portion A shown in  FIG. 12 . 
     As shown in  FIGS. 11 and 12 , an electronic apparatus body  1  according to the present embodiment includes a first front-side enclosure  2 , a circuit board, which will be described later, and a second back-side enclosure  3  containing the circuit board and forming a housing together with the first enclosure  2 . 
     As shown in  FIG. 11 , the first enclosure  2  includes, in the same surface (front surface), a liquid crystal (LC) display portion  4  having a rectangular outer shape for displaying visible information converted from an information signal; a key input portion  5  composed of a plurality of first input keys  5   a  arranged in a plurality of lines along the lower longer side of the liquid crystal display portion  4 ; and auxiliary keys  6  disposed on the right side with respect to the liquid crystal display portion  4  for assisting an input operation performed by operating the plurality of first input keys  5   a.    
     As shown in  FIG. 12 , the second enclosure  3  includes a camera  7  provided at an upper center portion of the enclosure, and elliptic trigger buttons (second input keys)  8  disposed respectively on both the right and the left sides with respect to the camera  7  for functioning as trigger switches for a barcode reader. Further, the second enclosure  3  is provided with battery packs  9  on both the left and the right sides thereof. Each of the battery packs  9  includes a lid  9   a  that can be removed when replacing a battery (not shown). Opposing edge portions  9   b  of the pair of left and right battery packs  9  are portions with which the tips of fingers except thumbs come into contact when holding and operating the electronic apparatus body  1  with both hands. Further, screw holes  10  are formed respectively on a pair of upper left and upper right corner portions of the second enclosure  3 . Thus, a pair of upper left and upper right corner portions of a strap device  12 , which will be described later, can be fixed to the pair of upper left and upper right corner portions of the second enclosure  3  with screws. 
     As shown in  FIGS. 12 and 13 , hook portions  11  are formed on a pair of lower left and lower right corner portions of the second enclosure  3 . Thus, a pair of lower left and lower right corner portions of the belt base  13  of the strap device  12 , which will be described later, can be attached to the pair of lower left and lower right corner portions of the second enclosure  3 . 
     It should be noted that, in the electronic apparatus body  1 , the circuit board (not shown) equipped with a signal processing circuit for processing an input signal received from the key input portion  5  or the like or a display signal to be displayed on the liquid crystal display portion  4  is disposed. 
     Strap Device 
     Next, the strap device according to the present embodiment will be described.  FIG. 4  is a front view showing the strap device according to Embodiment 2 of the present invention.  FIG. 5  is a back view showing the strap device according to Embodiment 2 of the present invention.  FIG. 6  is a cross-sectional view along the IV-IV line in  FIG. 4 .  FIG. 7  is a front view showing the strap device according to Embodiment 2 of the present invention in a state where the strap belt is open.  FIG. 8  is a front view showing the strap device according to Embodiment 2 of the present invention, for describing how to adjust the length of the strap belt.  FIG. 9  is a front view showing the strap device according to Embodiment 2 of the present invention attached to the back of the electronic apparatus body. 
     As shown in  FIGS. 4 to 6 , a strap device  12  according to the present embodiment includes: a substantially plate-shaped belt base  13  to be attached to an object; and a strap belt  14  formed in an annular shape and supported by a substantially center portion of the belt base  13  rotatably within a plane substantially parallel to the belt base  13 . The belt base  13  is composed of a back part provided with a pivot fitting  15  as a bearing member for supporting the belt base  13  rotatably and a front part facing the back part. The strap belt  14  extends across the belt base  13  from the front part to the back part of the belt base  13 . Since the strap device  12  has such a configuration, a part of the annular strap belt  14  positioned on the back side of the belt base  13  is pressed by the belt base  13  when the strap device  12  is attached to, for example, the back of the electronic apparatus body  1  (see  FIG. 9 ), and the shape of the strap belt  14  can be stabilized. It should be noted that the strap belt  14  can be rotated about plus or minus 20° from the state shown in  FIG. 4  (see arrows B and C in  FIG. 4 ). 
     Further, the strap belt  14  projects beyond from each of opposing left and right outer edges of the belt base  13 , thereby allowing the rotation movement of the strap belt  14  with respect to the belt base  13 . 
     Further, concave notches  23  and  24  are formed on the left and the right outer edges of the belt base  13 , respectively. By adopting such a configuration, the rotation movement of the strap belt  14  with respect to the belt base  13  can be allowed while the strap belt  14  can be downsized. 
     Notches  16  and  17  are formed on upper and lower outer edges of the belt base  13 , respectively. The upper and the lower outer edges couple between the left and the right outer edges from which the strap belt  14  projects. As described above, the camera  7  is provided at the upper center portion of the second enclosure  3  of the electronic apparatus body  1 . The upper notch  16  is for preventing the camera  7  from being hidden by the strap device  12  when the strap device  12  is attached to the second enclosure  3  positioned on the back side of the electronic apparatus body  1  (see  FIG. 9 ). Further, as described above, the opposing edge portions  9   b  of the pair of battery packs  9  provided respectively on both the left and the right sides of the second enclosure  3  of the electronic apparatus body  1  are the portions with which the tips of the fingers except thumbs come into contact when the electronic apparatus body  1  is held and operated with both hands. The lower notch  17  is for preventing the edge portions  9   b  from being hidden by the strap device  12  when the strap device  12  is attached to the second enclosure  3  positioned on the back side of the electronic apparatus body  1  (see  FIG. 9 ). Furthermore, elliptic openings  22  are formed on upper left and upper right sides of the belt base  13 , respectively. As described above, the elliptic trigger buttons  8  are provided on the upper left and the upper right sides of the second enclosure  3  of the electronic apparatus body  1 . The openings  22  are for preventing the trigger buttons  8  from being hidden by the strap device  12  when the strap device  12  is attached to the second enclosure  3  positioned on the back side of the electronic apparatus body  1  (see  FIG. 9 ). 
     A protrusion  18 , which protrudes toward the strap belt  14  side, is provided at a substantially center portion of the front side of the belt base  13 . Thus, when a palm is placed through the strap belt  14 , the protrusion  18  comes to the dinted portion of the palm (see  FIG. 10 ). By providing the protrusion  18 , when placing the palm into the strap belt  14  and holding the electronic apparatus body  1  as the object with the palm, the protrusion  18  fits into the dinted portion of the palm, thereby allowing a user to hold the electronic apparatus body  1  easily without exerting extra force. Thus, the electronic apparatus body  1  can be used comfortably. It is preferable that the protrusion  18  is rounded. 
     Screw insertion holes  19  as attachment members are provided at a pair of upper left and upper right corner portions of the belt base  13 , respectively. Thus, the strap device  12  can be attached to the back side of the electronic apparatus body  1  by placing the screw insertion holes  19  of the belt base  13  over screw holes  10  on the electronic apparatus body  1  side, and fixing the strap device  12  to the electronic apparatus body  1  with screws  20  (see  FIG. 9 ). Further, engagement fittings  21  as attachment members are provided at a pair of lower left and lower right corner portions of the belt base  13 , respectively. Thus, when attaching the strap device  12  to the back side of the electronic apparatus body  1 , the engagement fittings  21  of the belt base  13  can be engaged with the hook portions  11  (see  FIG. 13 ) on the electronic apparatus body  1  side (see  FIG. 9 ). In this way, the attachment members provided at the pair of lower left and lower right corner portions of the belt base  13  are attachable to and detachable from the electronic apparatus body  1 . Thus, replacement of the batteries of the electronic apparatus body  1  can be performed easily by disengaging the engagement fittings  21  provided at the pair of lower left and lower right corner portions of the belt base  13  from the hook portions  11  on the electronic apparatus body  1  side, and removing the lids  9   a  of the battery packs  9 . 
     As shown in  FIGS. 7 and 8 , the strap belt  14  of the strap device  12  includes: a strip-shaped belt member  14   a  whose midpoint is supported rotatably by the center portion of the back side of the belt base  13 ; an insertion fitting  14   b  provided at one end portion of the belt member  14   a  and into which the other end portion of the belt member  14   a  is inserted, and a holding and fixing member  14   c  provided on the other end portion side of the belt member  14   a  for holding (sandwiching) and fixing the other end portion of the belt member  14   a  in a state of being inserted in the insertion fitting  14   b . Here, a pair of hook-and-loop fasteners (not shown) provided at the other end portion of the belt member  14   a  and on the holding and fixing member  14   c  hold and fix the other end portion of the belt member  14   a . By holding and fixing the other end portion of the belt member  14   a  in the state of being inserted in the insertion fitting  14   b  in the above manner, the strap belt  14  is formed in an annular shape. In this case, by adjusting the length of the other end portion of the belt member  14   a  inserted into the insertion fitting  14   b , the size of the strap belt  14  in an annular shape can be changed in accordance with the size of a user&#39;s hand. 
     The Use of the Strap Device and the Electronic Apparatus Body Equipped with the Strap Device 
     Next, the use of the strap device and the electronic apparatus body equipped with the strap device according to the present embodiment will be described. 
       FIG. 10  is a front view showing a condition of use of the electronic apparatus body equipped with the strap device according to Embodiment 2 of the present invention. 
     The strap device  12  according to the present embodiment is used in a state of being attached to the back side of the electronic apparatus body  1  (see  FIG. 9 ). The strap device  12  is attached to the electronic apparatus body  1  as follows. First, the screw insertion holes  19  at the pair of upper left and upper right corner portions of the belt base  13  are placed over the screw holes  10  on the electronic apparatus body  1  side, and the strap device  12  is fixed to the electronic apparatus body  1  with the screws  20 . Then, the engagement fittings  21  provided at the pair of lower left and lower right corner portions of the belt base  13  are engaged with the hook portions  11  on the electronic apparatus body  1  side. After attaching the strap device  12  to the electronic apparatus body  1  in the above manner, the left hand is placed through the strap belt  14  and the electronic apparatus body  1  is held with the palm of the left hand while the first input keys  5   a  are operated with the right hand. In this case, the strap belt  14 , through which the palm of the left hand is placed, is supported by the substantially center portion of the belt base  13  attached to the electronic apparatus body  1  rotatably within a plane substantially parallel to the belt base  13 . Thus, as shown in  FIG. 10 , the visibility of the liquid crystal display portion  4  and the operability of the key input portion  5  and the touch panel can be improved by rotating the electronic apparatus body  1  without having to tilt the electronic apparatus body  1  with the wrist. As a result, even if the electronic apparatus body  1  is used for long hours by holding it with the left hand, the wrist does not get tired. Further, since the strap belt  14  can be rotated clockwise and counterclockwise with respect to the belt base  13  (the electronic apparatus body  1 ), both a right-handed user and a left-handed user can obtain similar effects by using the strap device  12 . Further, as described above, since the electronic apparatus according to the present embodiment is easy to hold and has excellent operability, it is possible to reduce the chances of the electronic apparatus body  1  held with the palm placed through the strap belt being dropped. Consequently, it is possible to reduce breakdown of the electronic apparatus body  1  or to reduce the chances of the user himself or people in the surroundings being injured as a result of dropping the electronic apparatus body  1 . 
     In the strap device  12  according to the present embodiment, the concave notches  23  and  24  are formed at the left and the right outer edges of the belt base  13 . However, these concave notches  23  and  24  are not absolute necessities. 
     Further, in the strap device  12  according to the present embodiment, the notches  16  and  17  are formed respectively at the upper and the lower outer edges of the belt base  13  coupling between the left and the right outer edges from which the strap belt  14  projects. The notch needs to be formed on at least the upper or the lower outer edge. Further, when a camera or the like is not provided on the back side of the electronic apparatus body as an object, it is not necessary to form the notches at the upper and the lower outer edges of the belt base. 
     Further, the strap device  12  according to the present embodiment includes the protrusion  18  that comes to the dinted portion of a palm when the palm is placed through the strap belt. However, the protrusion  18  is not an absolute necessity. 
     Further, in the strap device  12  according to the present embodiment, the belt base  13  is composed of the back part provided with the pivot fitting  15  as a bearing member for supporting the strap belt  14  rotatably; and a front part facing the back part, and the strap belt  14  extends across the belt base  13  from the front part to the back part of the belt base  13 . However, the strap device  12  is not necessarily limited to such a configuration. For example, the annular strap belt may be placed on the front side of the belt base and may be supported by the front side of the belt base. In this case, the protrusion, which comes to the dinted portion of a palm when the palm is placed through the strap belt, is provided to the strap belt as needed. 
     Further, in the strap device  12  according to the present embodiment, only the attachment members on the pair of lower left and lower right corner portions of the belt base  13  are attachable to and detachable from the object (the electronic apparatus body  1 ). It is useful for the attachment members on at least either the pair of upper left and upper right corner portions or the pair of lower left and lower right corner portions of the belt base to be attachable to and detachable from the object. However, when the electronic apparatus body as the object is not provided with the battery packs including replaceable lids on the back side, none of the attachment members at the corner portions of the belt base may need to be attachable to and detachable from the object. 
     It should be noted that the attachment members at the respective corner portions of the belt base do not need to be provided at the positions that coincide with the respective corner portions of the second enclosure of the electronic apparatus body. If a user can hold the electronic apparatus body, the area of the belt base may be smaller than that of the back side of the second enclosure. 
     Though the embodiments described above refer to examples of a notebook PC and a PDA, the strap device of the present invention can be widely applied to, for example, a game machine, a portable navigation system, or a terminal used in nursing for collecting patients&#39; day-to-day data and transmitting it to a host computer. 
     As described above, according to the present invention, it is possible to provide a strap device capable of, when used in a state of being attached to an electronic apparatus body including a display portion and a key input portion as the object, improving the visibility of the display portion and the operability of the key input portion or the touch panel without tilting the electronic apparatus body with the wrist. Thus, the present invention is useful as a strap device for improving the portability of an electronic apparatus with excellent portability such as a notebook PC, a PDA, a game machine, or a terminal used in nursing. 
     The invention may be embodied in other forms without departing from the sprit of essential characteristics thereof. The embodiments disclosed in this application are to be considered in all respects as illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.