Abstract:
A hinge assembly has a tubular member having a longitudinal axis, a peripheral surface, and a slot formed in the peripheral surface. A button member extends into the tubular member to undergo sliding movement in an axial direction along the longitudinal axis of the tubular member and to undergo rotational movement relative to the tubular member. A pin member is connected to the button member and extends into the slot of the tubular member to undergo movement therein during sliding and rotational movement of the button member relative to the tubular member. The button member is biased in a preselected direction of rotation relative to the tubular member by a first biasing member. The button member is biased in an axial direction by a second biasing member.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a hinge assembly having at least one hinge unit of a mounting strap for use with a portable information apparatus. 
     2. Description of the Prior Art 
     Generally, as a mounting strap for mounting a wrist watch or a portable apparatus such as a wrist watch type communication apparatus or a wrist watch type information apparatus represented by a PHS (Personal Handyphone System) communication terminal onto the arm, there is known, for example, a mounting strap mounted onto the arm by connecting together two pieces of a 6 o&#39;clock side strap and a 12 o&#39;clock side strap connected to two opposed ends (hereinafter, referred to as “6 o&#39;clock side” and “12 o&#39;clock side”) of a case main body of a portable apparatus by locking thereof by buckles. Herein, such a type strap is referred to as a strap of a buckle type. There is known a strap of the buckle type made of skin or made of fiber having buckles or made by a metal chain having bindings. 
     Further, other than the strap of the buckle type, there is known a strap of a bangle type formed in a predetermined shape capable of surrounding the arm by a 6 o&#39;clock side strap and a 12 o&#39;clock side strap. The strap of the bangle type is mounted onto the arm by fixing the strap in a state of being fitted to pinch the arm without connecting together the 6 o&#39;clock side strap and the 12 o&#39;clock side strap. There is constructed a structure in which in opening and closing the strap of the bangle type, when the strap is detached in a state of being fitted to the arm, the 6 o&#39;clock side strap or the 12 o&#39;clock side strap is pulled to open directly by force of the hand of a user, further, when the strap is fitted thereto in an opened state, the 6 o&#39;clock side strap or the 12 o&#39;clock side strap is pushed to close directly by the force of the hand of the user. 
     However, according to the above-described conventional mounting strap of the buckle type, the 6 o&#39;clock side strap and the 12 o&#39;clock side strap are connected together by the buckles and locked to prevent from being readily detached and firmly fitted to the arm and therefore, the operability in attaching and detaching thereof is poor. Further, even in the case of the mounting strap of the bangle type referred to also as a bracelet type, there poses a problem that the opening and closing operation is carried out directly by the force of the hand of the user per se and therefore, the operability in attaching and detaching thereof is poor. 
     SUMMARY OF THE INVENTION 
     Hence, the invention has been carried out in view of the above-described drawbacks in the conventional art and it is an object thereof to provide a hinge unit for opening or closing a mounting strap of a bangle type facilitating attaching and detaching thereof and having an excellent fitting feeling. 
     In order to achieve the above-described object, according to an aspect of the invention, there is provided a hinge unit of a mounting strap characterized in comprising a rotational pipe member formed with a hole in an L-like shape perforated in the L-like shape toward a peripheral direction and an axial direction at a side face thereof, a button member inserted to the rotational pipe member, a fixed member projected and inserted into the hole in the L-like shape of the rotational pipe member and connected to the button member, an axial direction elastic member for urging the rotational pipe member and the button member to each other such that the fixed member is butted to a side of a terminal end in the axial direction of the hole in the L-like shape of the rotational pipe member, and a rotational direction elastic member for urging the rotational pipe member and the button member to each other such that the fixed member is butted to a side of a terminal end in a peripheral direction of the hole in the L-like shape of the rotational pipe member, wherein either one of the rotational pipe member and the fixed member is attached to a case main body of a portable apparatus and other thereof is attached to a strap piece to thereby axially fix the strap piece rotatably to one end side or other end side of the case main body. 
     Thereby, as described later, by axially fixing the strap piece rotatably to the one end side or the other end side of the case main body, the user can detach the mounting strap from the arm and mount the mounting strap thereto by operation of pushing the button member. 
     According to another aspect of the invention, there is provided a hinge unit of a mounting strap characterized in comprising a rotational pipe member formed with a hole in an L-like shape perforated in the L-like shape in a peripheral direction and an axial direction at a side face thereof, a slide pipe member inserted to the rotational pipe member and formed with a long hole perforated to direct skewedly relative to the axial direction at a side face thereof, a button member inserted into the slide pipe member, a fixed member projected and inserted to the hole in the L-like shape of the rotational pipe member and the long hole of the slide pipe member and connected to the button member, an adjusting mechanism for adjusting a range of rotating the rotational pipe member relative to the slide pipe member by changing a length of the slide pipe member relative to the rotational pipe member, an axial direction elastic member for urging the slide pipe member and the button member to each other such that the fixed member is butted to a side of a terminal end in the axial direction of the hole in the L-like shape of the rotational pipe member, and a rotational direction elastic member for urging the rotational pipe member and the slide pipe member to each other such that the fixed member is butted to a side of the terminal end in the peripheral direction of the hole in the L-like shape of the rotational pipe member, wherein either of the rotational pipe member and the fixed member is attached to a case main body of a portable apparatus and other thereof is attached to a strap piece to thereby axially fix the strap piece rotatably to one end side or other end side of the case main body. 
     Thereby, as described later, by axially fixing the strap piece rotatably to the one end side or the other end side of the case main body, a user can detach the mounting strap from the arm and mount the mounting strap thereto by operation of pushing the button member. 
     Further, the fixed member is regulated not only by the hole in the L-like shape of the rotational pipe member but also by the long hole of the slide pipe member and therefore, when a length of the slide pipe member relative to the rotational pipe member is adjusted, in accordance with a pitch of the long hole, the range of rotating the rotational pipe member is changed and a ring diameter formed by the mounting strap can finely be adjusted. 
     Further, according to the hinge unit of the mounting strap of the invention, when the fixed member is butted to a side of a terminal end in the axial direction of the hole in the L-like shape, the strap piece is axially fixed rotatably to the one end side or the other end side of the case main body such that the mounting strap is stabilized in a state of being closed. 
     Thereby, when the button member is pushed into the rotational pipe member (or the slide pipe member) until the fixed member is butted to a portion intersected with the axial direction and peripheral direction of the hole in the L-like shape, the button member is slid to a side of a terminal end in the peripheral direction of the hole in the L-like shape by urge force by the rotational direction elastic member and the rotational pipe member is rotated relative to the button member to thereby rotate the strap piece in an opening direction relative to the case main body. Therefore, the user can detach the mounting strap by one touch operation since the strap piece can be opened by operation of pushing the button member. 
     Further, according to the hinge unit of the mounting strap of the invention, when the fixed member is butted to the side of the terminal end in the axial direction of the hole in the L-like shape, the strap piece is axially fixed rotatably to the one end side or the other end side such that the mounting strap is stabilized in a state of being opened. 
     Thereby, when the button member is pushed into the rotational pipe member (or the slide pipe member) until the fixed member is butted to the portion intersected with the axial direction and the peripheral direction of the hole in the L-like shape, the button member is slid to the side of the terminal end in the peripheral direction of the hole in the L-like shape by urge force of the rotational direction elastic member to thereby rotate the strap piece in the direction of being closed relative to the case main body. Therefore, the user can attach the mounting strap to the arm by one touch operation since the strap piece can be closed by operation of pushing the button member. 
     Further, a stepped portion may be formed at the terminal end in the axial direction of the hole in the L-like shape and the fixed member may be fitted to the stepped portion. 
     Further, it is preferable to provide a button bar for bridging the respective button members of the hinge unit axially fixed to the one end side of the case main body of the portable apparatus and the hinge unit axially fixed to the other end side to thereby connect each other. Thereby, the hinge units at the both ends can simultaneously be operated and therefore, attaching and detaching by one touch operation is facilitated. 
     The hole in the above-described L-like shape is provided when the rotational pipe member is viewed from an outer side thereof and there is included also a Γ-like shape constituting a shape of a mirror image thereof. The hinge unit can correspond to either of one touch release and one touch mounting by a difference of the L-like shape and the Γ-like shape. Further, the hinge unit can deal with either of one touch release and one touch mounting by attaching the hinge unit by changing a direction of axial fixing by 180. 
     Further, it is preferable to mold the strap piece in a bow-like shape by injection molding since a feeling of fitting to the arm is promoted. Further, the shape is not limited to the bow-like shape so far as the shape is the shape capable of surrounding the arm in a ring-like shape. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred form of the present invention is illustrated in the accompanying drawings in which: 
     FIG. 1 is a sectional view of a wrist watch type PHS communication terminal according to Embodiment 1 of the invention; 
     FIG. 2 is a perspective view for explaining a pipe hinge unit according to Embodiment 1 of the invention; 
     FIG. 3 is a disassembled perspective view for explaining an assembled state of the pipe hinge unit according to Embodiment 1 of the invention; 
     FIG. 4 is a disassembled perspective view for explaining development of a connecting portion of a case main body according to Embodiment 1 of the invention; 
     FIG. 5 is a sectional view for explaining the portion of connecting the case main body and a 12 o&#39;clock side strap according to Embodiment 1 of the invention; 
     FIG. 6 is a perspective view for explaining an operational state of the pipe hinge unit according to Embodiment 1 of the invention; 
     FIG. 7 is a perspective view for explaining an operational state of the pipe hinge unit according to Embodiment 1 of the invention; 
     FIG. 8 is a perspective view for explaining an operational state of the pipe hinge unit according to Embodiment 1 of the invention; 
     FIG. 9 is a side view for explaining operational states of the pipe hinge unit according to Embodiment 1 of the invention; 
     FIG. 10 is a perspective view for explaining a wrist watch type PHS communication terminal according to Embodiment 2 of the invention; and 
     FIG. 11 is a partially cut sectional view of the wrist watch type PHS communication terminal according to Embodiment 2 of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A detailed explanation will be given of the invention with reference to the drawings as follows. Further, the invention is not limited by the embodiments described herein. Further, an explanation will be given of the embodiments by taking an example of a mounting strap used for a PHS (Personal Handyphone System) communication terminal of a wrist watch type communication apparatus. 
     (Embodiment 1) 
     FIG. 1 is a sectional view of a wrist watch type PHS communication terminal showing Embodiment 1 of the invention. The wrist watch type PHS communication terminal  100  is constituted by a case main body  10  and a mounting strap  40  in a ring-like shape comprising a 12 o&#39;clock side strap  20  in a bow-like shape rotatably attached to the case main body  10  on a 12 o&#39;clock side of the case main body  10  and a 6 o&#39;clock side strap  30  in a bow-like shape rotatably attached to the case main body  10  on a 6 o&#39;clock side of the case main body  10 . 
     The case main body  10  includes a PHS communication unit  13  comprising electronic parts for carrying out PHS communication such as an antenna, a battery and a display panel in a space hermetically closed by a glass member  11  for protecting a display panel attached on a surface side and a case back  12  attached to a rear face side thereof. The 12 o&#39;clock side strap  20  is formed in the bow-like shape by integrating an upper strap  20   a  and lower straps  20   b  and  20   c  and includes a speaker  21 , a sheet board  22  and wirings  23  and  24  for electrically connecting these to the PHS communication unit  13 . 
     Further, the 10 o&#39;clock side strap  20  is axially supported rotatably relative to the case main body  10  by a hinge assembly having a pipe hinge unit  50 , urged to rotate from a closed state indicated by bold lines to an opened state indicated by two-dotted chain lines and is fixed to maintain the closed state indicated by the bold lines. Further, as described later, the wrist watch type PHS communication terminal  100  can be detached from the arm by bringing the 12 o&#39;clock side strap  20  from the closed state to the opened state by one touch operation of the pipe hinge unit  50 . 
     Meanwhile, the 6 o&#39;clock side strap  30  is formed in the bow-like shape by integrating an upper strap  30   a  and lower straps  30   b  and  30   c  and includes a microphone  31 , an operational button unit  32  and wirings  33  and  34  for electrically connecting these to the PHS communication unit  13 . Further, similarly, the 6 o&#39;clock side strap  30  is axially supported rotatably relative to the case main body  10  by a pipe hinge unit  60  of the hinge assembly, urged to rotate from a closed state indicated by bold lines to an opened state indicated by two-dotted chain lines and fixed to maintain the closed stated indicated by the bold lines. Further, as described later, the wrist watch type PHS communication terminal  100  can be detached from the arm by bringing the 6 o&#39;clock side strap  30  from the closed state to the opened state by one touch operation of the pipe hinge unit  60 . 
     Next, an explanation will be given of the structure of the pipe hinge unit  50 . Further, the same structure applies to the pipe hinge unit  60 . FIG. 2 is a perspective view for explaining the pipe hinge unit according to Embodiment 1 of the invention. FIG. 3 is a disassembled perspective view showing an assembled state of the pipe hinge unit according to Embodiment 1 of the invention. As shown by FIG. 2 or FIG. 3, the pipe hinge unit  50  comprises respective parts of a slide pipe  51 , a rotational tubular member  52  (hereinafter “rotational pipe”), a pipe return spring  53  constituting a first biasing member, a button  54 , a button extracting spring  55  constituting a second biasing member, a fixed pin  56  and a unit fixing screw  57 . 
     The slide pipe  51  is formed in a shape integrated with a hollow member one end side of which is opened and a rod-like member formed at other end side of the hollow member and, is formed with a fixed pin slide hole  51   a,  a pipe return spring engaging groove  51   b,  a case inserting portion  51   c,  a slide pipe drawing screw portion  51   d,  a hollow hole portion  51   e  and a fixed pin regulating face  51   f,  mentioned later. The fixed pin slide hole  51   a  is a hole formed at a peripheral face of the hollow member skewedly relative to the axial direction (spirally) with a width by which the fixed pin  56  can be inserted and is a hole through which the fixed pin  56  slides when the slide pipe  51  per se is rotated. That is, when the fixed pin  56  is fixed, rotation of the slide pipe  51  is regulated by the fixed pin  56 . 
     The pipe return spring engaging groove  51   b  is inserted with a slide pipe inserting bent portion  53   b  of the pipe return spring  53 . The case inserting portion  51   c  is inserted into a side of the case main body  10 , mentioned later. The slide pipe drawing screw portion  51   d  is screwed with the unit fixing screw  57 . The hollow hole portion  51   e  is inserted with the button  54 . 
     The rotational pipe  52  is a pipe both ends of which are opened and is formed with a fixed pin slide slot or hole  52   a , a pipe return spring engaging groove  52   b  forming a longitudinal extension of the fixed pin slide hole  52   a , a strap regulating portion  52   c , a fixed pin settling stepped portion  52   d  and a hollow hole portion  52   e . The fixed pin slide hole  52   a  is a hole formed in an L-like shape at a peripheral face of the rotational pipe  52  with a width by which the fixed pin  56  can be inserted. The pipe return spring engaging groove  52   b  is inserted with a rotational pipe inserting bent portion  53   a  of the pipe return spring  53 . The strap regulating face portion  52   c  is brought into contact with an end face of a strap to thereby regulate rotation of the strap, as mentioned later. 
     The fixed pin settling stepped portion  52   d  is a portion provided by recessing one end side of the fixed pin slide hole  52   a  extended in the axial direction of the rotational pipe  52  and is a portion fitted with the fixed pin  56  to thereby prevent the rotational pipe  52  and the slide pipe  51  from being rotated, as mentioned later. The hollow hole portion  52   e  is inserted with the slide pipe  51  from one end side and inserted with the unit fixing screw  57  from other end side thereof. 
     The pipe return spring  53  is a spring in a helical shape formed with the rotational pipe inserting bent portion  53   a  and the slide pipe inserting bent portion  53   b,  however, the pipe return spring  53  is not limited to the helical spring but may be, for example, rubber so far as the portion is constituted by an elastic member exerting urge force operated between the slide pipe  51  and the rotational pipe  52  respectively in the rotational direction. The pipe return spring  53  is integrated between the rotational pipe  52  and the slide pipe  51  inserted into the rotational pipe  52 . The rotational pipe inserting bent portion  53   a  of the pipe return spring  53  is inserted into the pipe return spring engaging groove  52   b  and another member of the slide pipe inserting bent portion  53   b  thereof is inserted into the pipe return spring engaging groove  51   b.  Thereby, when the slide pipe  51  is rotated and fixed and the rotational pipe  52  is rotated, reaction force is operated. 
     The button  54  is formed with a fixed pin fixing hole  54   a . The fixed pin fixing hole  54   a  is a hole fitted with the fixed pin  56  in a state in which the button  54  is inserted into the hollow hole portion  51   e  of the slide pipe  51 . Under this state, the fixed pin  56  is inserted into the fixed pin slide hole  51   a  and the fixed pin slide hole  52   a  and the button  54  is made movable in the axial direction in a range of not being disengaged from the slide pipe  51  by regulating the fixed pin  56  by the fixed pin slide hole  51   a.    
     Further, movement of the fixed pin  56  is regulated also by the fixed pin slide hole  52   a  and accordingly, movement of the button  54  relative to the rotational pipe  52  is regulated by the fixed pin settling stepped portion  52   d.    
     The button extracting spring  55  is a helical spring inserted into the depth side of the hollow hole portion  51   e  for exerting urge force directed to an outer side relative to the button  54 . Also the button extracting spring  55  is not limited to the helical spring but may be, for example, rubber so far as the portion is an elastic member exerting the urge force directed to the outer side relative to the button  54 . The fixed pin  56  regulates rotation of the slide pipe  51  and the rotational pipe  52 . The unit fixing screw  57  is attached to make the slide pipe  51  and the rotational pipe  52  rotatable to each other. 
     Next, an explanation will be given of a portion for connecting the case main body  10  and the 12 o&#39;clock side strap  20 . FIG. 4 is a disassembled perspective view for explaining the portion of connecting the case main body according to Embodiment 1 of the invention. In the case main body  10 , a recessed groove portion  10   a  is formed at inside of an inserting hole  10   b  for inserting the pipe hinge unit  50 , an inserting hole  10   c  is formed coaxially with the inserting hole  10   b  and a curved face portion  10   d  is formed on a side of the inserting hole  10   c.    
     Further, the case back  12  is formed with a hook portion  12   a  forming a curved face. Similarly, the lower strap  20   b  is also formed with a hook portion  20   d  forming a curved face. The hook portions  12   a  and  20   d  constitute one inserting hole in a state of being integrated with the inserting hole  10   c  and the curved face portion  10   d.  Further, the upper strap  20   a  is formed with a projected portion  20   e  at inside of an inserting hole  20   f  for inserting the pipe hinge unit  50 . The sheet board  22  is connected to a sheet board  22   b  on a side of the case main body  10  by interposing a cylindrical member  22   a  therebetween. The cylindrical member  22   a  is sandwiched at a portion surrounded by the curved face portion  10   d  and the hook portions  12   a  and  20   d.    
     FIG. 5 is a sectional view for explaining the portion of connecting the case main body and the 12 o&#39;clock side strap according to Embodiment 1 of the invention. The pipe hinge unit  50  is inserted and axially fixed to connect the case main body  10  and the 12 o&#39;clock side strap  20 . That is, the pipe hinge unit  50  is axially fixed by coupling the strap regulating portion (rotation regulating portion)  52   c  of the rotational pipe  51  with the projected portion  20   e  (upper strap  20   a ) and inserting the case inserting portion (projection)  51   c  of the slide pipe  51  into the recessed groove portion  10   a  of the case main body  10 . 
     Next, an explanation will be given of operational states of the pipe hinge unit having the above-described constitution in opening and closing the strap. FIG. 6, FIG. 7, FIG.  8  and FIG. 9 are perspective views for explaining operational states of the pipe hinge unit according to Embodiment 1 of the invention. Further, in the following explanation, FIG. 5 is pertinently referred to. 
     First, when the strap is closed from the state in which the strap is opened (in FIG. 1, the 12 o&#39;clock side strap  20  (6 o&#39;clock side strap  30 ) is brought from the state indicated by the two-dotted chain lines to the state indicated by the bold lines), as shown by an operational state view of FIG. 6, rotation of the slide pipe  51  relative to the case main body  10  is regulated by fitting the case inserting portion  51   c  to the recessed groove portion  10   a,  further, since the slide pipe  51  is fixed by the projected portion  20   e  and the strap regulating portion  52   c,  when the rotational pipe  52  is rotated by force F 1 , there is brought about a state in which reaction by the pipe return spring  53  is operated. 
     At this occasion, when the rotational pipe  52  is further rotated and reaches a state shown by FIG. 7, since the button  54  having the fixed pin  56  integrated to inside of the slide pipe  51 , is exerted with force F 3  by the button extracting spring  55 , there is brought about a state in which the fixed pin  56  starts to enter the fixed pin slide hole  52   a  in the L-like shape of the rotational pipe  52  in the axial direction. Then, the fixed pin  56  is brought into a state of being sandwiched between the fixed pin regulating face (wall face)  51   f  of the slide pipe  51  and the fixed pin settling stepped portion (wall face)  52   d  of the rotational pipe  52  and there is brought about a state shown by FIG. 8 in which even force of closing the strap is released, the strap is held. 
     Conversely, with regard to a mechanism for detaching the strap, the state shown in FIG. 8 is brought into the state shown by FIG.  7  and the state shown by FIG. 6 finally. That is, by pushing in the button  54 , the fixed pin  56  rides over the fixed pin settling stepped portion (groove)  52   d,  the fixed pin  56  and the rotational pipe  52  are separated from each other and the rotational pipe  52  is rotated by the strap return spring  53  having reaction force. Thereby, the strap can be detached from the arm. 
     Next, an explanation will be given of a mechanism of adjusting a wrapping angle according to the size of the arm. An explanation will be given of fine adjustment operation by the pipe hinge unit  50  described above. As shown by FIG.  5  and FIG. 9, there is provided a gap A between the slide pipe  51  and the case main body  10  (also between the slide pipe  51  and the rotational pipe  52 ) and the gap can be elongated and contracted in the left and right direction by the unit fixing screw (fine adjustment screw)  57 . Further, since the fixed pin slide hole  51   a  of the slide pipe  51  is provided with a twisted shape and accordingly, by elongating or contracting the unit fixing screw  57 , as shown by FIG. 9, the position of the fixed pin regulating face  51   e  for sandwiching the fixed pin  56  is changed in the rotational direction. Thereby, the position of the fixed pin settling stepped portion  52   d  fitted with the fixed pin  56  relative to the fixed pin slide hole  51   a,  is also changed and by changing a position of locking the strap in accordance with a pitch of the fixed pin slide hole  51   a,  a set position of the arm of respective person can be determined. 
     According to the above-described embodiment, there are provided the pipe hinge units at hinge portions of the case and the straps and therefore, there is achieved an effect that the straps of the bangle type can be opened and closed by one touch operation, further, the straps are fitted to the arm of respective person in steps. Further, between two pairs of the pipes rotated coaxially, the fixed pins are fitted to the fixed pin settling stepped portions and therefore, firm locking can be carried out. Therefore, the strap can be opened and closed instantaneously relative to the arm and can be fitted to the arm of respective person at a stable position and therefore, particularly, there is achieved further excellent effect when the strap is used in a PHS communication terminal of a wrist watch type which needs to attach and detach frequently. 
     (Embodiment 2) 
     FIG. 10 is a perspective view for explaining a wrist watch type PHS communication terminal according to Embodiment 2 of the invention. FIG. 11 is a partially cut sectional view of the wrist watch type PHS communication terminal according to Embodiment 2 of the invention. Embodiment 2 is constituted by adding the constitution of Embodiment 1 with a button bar  71 , striking pins  72  and  74  and a sliding washer  73  shown below. That is, when the buttons of the hinge units  50  and  60  on the 12 o&#39;clock side and the 6 o&#39;clock side are bridged by the button bar  71  and the striking pines  72  ad  74 , the strap pieces  20  and  30  can simultaneously be opened by one touch operation. 
     Further, the sliding washers  73  and  75  fix the button bars  71  when the buttons of the hinge units  50  and  60  are rotated by a strap opening angle and operate to help rotate the buttons  50  and  60  and the button bar  71 . 
     Further, although according to the above-described embodiments, an explanation has been given by taking an example of the mounting strap used for the PHS communication terminal of the wrist watch type communication apparatus, the mounting strap can similarly be constituted and operated also for other portable apparatus such as other wrist watch type communication apparatus, wrist watch, wrist watch type information apparatus or the like. 
     Further, in the foregoing embodiments, an explanation has been given of the case in which the 10 o&#39;clock side strap  20  and the 6 o&#39;clock side strap  30  are urged in the opening direction, maintain the closed state and release the closed state. In an alternative embodiment, the straps are urged in the closing direction, maintain the opened state and release the opened state. Thus, a portable terminal can be mounted to the arm easily by one touch operation. In this case, the above-described pipe hinge unit is attached by changing the direction by 180 degrees to invert the rotational direction. 
     As has been explained above, according to the hinge unit of the mounting strap of the invention, there is achieved an effect in which by axially fixing the strap pieces rotatably to the one end side or the other end side of the case main body, a user can detach or mount the mounting strap from and to the arm by operation of pushing the button member. Further, there is achieved an effect of capable of providing inexpensively the mounting strap having high general purpose performance for a maker thereof. Particularly, in the case of a portable apparatus of an arm mounting type such as a PHS communication terminal which needs to fit to the arm to ensure the operability, there can be promoted attaching and detaching operability when the portable apparatus is operated by attaching and detaching thereof to and from the arm in a hurry.