Abstract:
A portable apparatus has a push button mounted on a casing for operating a contact inside the casing. The push button is axially slidable in a pipe fixed in a through-hole extending through the casing. A coil spring encircles the pipe and is interposed between a flange of the pipe and a head of the push button to urge the push button outwardly. A packing ring for sealing the space between the pipe and push button is attached to either the pipe or the push button in the region where the coil spring encircles the pipe. Since the coil spring overlaps the packing ring, the axial length of the pipe and push button can be shortened to reduce the size of the casing.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a portable apparatus and a portable timepiece having a push button. 
   2. Related Art 
   There is known a portable timepiece such as a wristwatch, a pocket watch or the like, a stopwatch, or a portable apparatus of a portable telephone, a portable type information terminal or the like, which has a push button for operating, for example, a contact or the like inside of an apparatus case. By pushing the push button by a predetermined stroke, for example, in a portable timepiece, a time display is switched from an analog display to a digital display or conversely thereto, or date or day of week displayed in digital form is corrected. 
   A portable apparatus of this kind includes a coil spring for urging the push button in a direction of pushing back the push button. Along therewith, a portable apparatus includes a ring-like packing for achieving waterproof at a portion at which the push button is installed by inserting the apparatus case. 
   Specifically, a pipe is inserted and attached in a through hole provided at a bottom wall of a recess portion of a surface of the apparatus case. A shaft portion of the push button is inserted to the pipe, and an outer periphery of the shaft portion is mounted with a packing for waterproof. The coil spring is interposed by a back face of an operating portion of the push button and the bottom wall of the recess portion, opposed thereto, and the shaft portion of the push button is passed to an inner portion of the spring. Therefore, the coil spring and the packing are provided to be aligned along an axial direction of the shaft portion of the push button (refer to, for example, Patent Reference 1). 
   [Patent Reference 1] JP-A-2000-230989 (paragraphs 0002-0006, paragraphs 0025-0038, FIG. 1-FIG. 3) 
   According to an arrangement of aligning the coil spring and the packing along the axial direction of the shaft portion of the push button as in the technology of Patent Reference 1, the shaft portion of the push button is provided with a shaft portion region for attaching the packing at a position which is shifted in the axial direction relative to a shaft portion region in correspondence with a height of the coil spring, and therefore, a total length of the push button is long. 
   Therefore, for example, when the push button is to be projected from an outer side face of a case body of the portable timepiece, the projected width is prolonged. In order to restrict the projected width of the push button to a predetermined length, the case body needs to be enlarged. However, thereby, the portable timepiece becomes large and heavy, and there is provided a design in which a thickness of a front face of the case body is large in the region around a cover glass for seeing therethrough a time display portion, which is not preferable. 
   It is an object of the invention to provide a portable apparatus and a portable timepiece capable of shortening a length in an axial direction of a push button. 
   SUMMARY OF THE INVENTION 
   In order to resolve the problem, a portable apparatus of the invention includes an apparatus exterior having a through hole, a pipe formed by providing an outwardly arranged cylinder portion having a spring receiving face integrally with an inserting cylinder portion, and fixed to the apparatus exterior by inserting the inserting cylinder portion to the through hole and arranging the outwardly arranged cylinder portion to an outer portion of the apparatus exterior, a push button including a shaft portion movably penetrating the pipe, a drawout preventing member attached to one end portion disposed in the apparatus exterior of the shaft portion for preventing the shaft portion from being drawn out from the pipe, and an operating head provided at other end of the shaft portion disposed at outside of the apparatus exterior, a coil spring interposed between the operating head and the spring receiving face for urging the push button to an outer side of the apparatus exterior, and a ring-like packing attached to either of the pipe and the push button within a range of a height of the coil spring and attached concentrically with the coil spring for sealing an interval between the pipe and the push button. 
   The portable apparatus of the invention is applicable to a portable timepiece of a wristwatch, a pocket watch or the like, a stopwatch, a portable telephone, a portable type information terminal or the like and the apparatus exterior indicates an exterior case or the like. In this disclosure “the coil spring urges the push button to the outer side of the apparatus exterior” and words of like import mean that when the push button is pushed from the front face of the apparatus exterior, the push button is urged to an upper side by the coil spring, and means that when the push button is pushed from the side face of the apparatus exterior, the push button is urged to the outer side by the coil spring. 
   In this disclosure “the height of the coil spring” means a length from one end to other end of the spring. Along therewith, in this disclosure, “the packing is attached within the range of the height of the coil spring” means that preferably, the packing is arranged in correspondence with an interval from one end of the coil spring supported by the spring receiving face to other end of the coil spring supported by the operating head. However, the constitution includes also an arrangement in a dimensional error range, that is, a case in which although most of the coil spring is arranged in correspondence with the interval from the one end to the other end of the coil spring, a portion of the coil spring passes the spring receiving face to arrange an imaginary line orthogonal to the shaft portion of the push button to exceed to a side of the drawout preventing member of the push button. In this disclosure, “concentrically attached” means an arrangement in which a center of the coil spring and the center of the packing coincide with each other when the push button is viewed in the axial direction. 
   According to the invention, the ring-like packing for sealing the interval between the pipe and the push button is not arranged by aligning with the coil spring along the axial direction of the shaft portion of the push button but arranged within the range of the height of the coil spring and concentrically with the coil spring. 
   Thereby, it is not necessary to ensure a region for attaching the packing at the shaft portion of the push button at a position shifted in the axial direction from the shaft portion region in correspondence with the height of the coil spring, and therefore, the length in the axial direction of the push button can be shortened in correspondence with the width dimension of the packing. 
   According to a preferable mode of the portable apparatus of the invention, the outwardly arranged cylinder portion includes a cylinder end portion extending outwardly from the spring receiving face and opposed to a portion of the coil spring on a side of the spring receiving face, and the packing is attached to the cylinder end portion. 
   According to this mode of the invention, the packing is attached to push the cylinder end portion to be directed to the end of the coil spring supported by the operating head, and therefore, the packing can be arranged concentrically with the coil spring in correspondence with the interval from the one end to the other end of the coil spring. 
   According to a preferable mode of the portable apparatus of the invention, the outwardly arranged cylinder portion includes a cylinder end portion extending outwardly from the spring receiving face and inserted between the coil spring and the shaft portion, and the packing is brought into contact with an inner periphery of the cylinder end portion to be attached to the shaft portion. 
   According to this mode of the invention, the packing attached to the shaft portion of the push button is brought into contact with the cylinder end portion to be directed to the end of the coil spring supported by the operating head, and therefore, the packing can be arranged concentrically with the coil spring in correspondence with the interval from the one end to the other end of the coil spring. 
   In order to resolve the aforementioned problem, a portable timepiece of the invention is formed using the portable apparatus of the invention of any. 
   The portable timepiece of the invention is formed using the portable apparatus of the invention, and therefore, a portable timepiece capable of shortening the length in the axial direction of the push button can be provided. 
   In order to resolve the aforementioned problem, a portable timepiece of the invention includes a timepiece exterior assembly including a case body having a recess portion opened to a case body outer face and provided with a through hole at an innermost wall of the recess portion, a pipe formed by providing an outwardly arranged cylinder portion having a spring receiving face integrally with an inserting cylinder portion, and fixed to the case body by movably inserting the inserting cylinder portion to the through hole and arranging the outwardly arranged cylinder portion at an outer portion of the case body, a push button having a shaft portion penetrating the pipe, a drawout preventing member attached to one end portion of the shaft portion disposed in the case body of the shaft portion for preventing the shaft portion from being drawn out from the pipe, and an operating head provided at other end of the shaft portion disposed at outside of the case body, a coil spring interposed between the operating head and the spring receiving face for urging the push button to an outer side of the case body and forming a gap enabling to push the push button between the innermost wall and the operating head, and a ring-like packing attached to either of the pipe and the push button within a range of a height of the coil spring and concentrically attached to the coil spring for sealing an interval between the pipe and the push button. 
   According to the portable timepiece of the invention, the ring-like packing for sealing the interval between the pipe and the push button is not arranged by aligning with the coil spring along the axial direction of the shaft portion of the push button but arranged within the range of the height of the coil spring and concentrically with the coil spring. 
   Thereby, it is not necessary to ensure a region for attaching the packing at the shaft portion of the push button at the position of being shifted from the shaft portion region in correspondence with the height of the coil spring in the axial direction, and therefore, the length in the axial direction of the push button can be shortened in correspondence with the width dimension of the packing. In other words, a projected width of the push button projected from a case body outer face in a side direction can be shortened. 
   According to a preferable mode of the portable timepiece of the invention, a thickness of from a case body inner face to the case body outer face of the case body is defined by a depth of the recess portion and a thickness of the innermost wall, and the innermost wall is made to be thinner than the gap. 
   According to the mode of the invention, the thickness of the innermost wall of the recess portion is made to be thinner than the gap enabling to push the push button, and therefore, the length of the shaft portion of the push button is further shortened and the projected width of the push button projected from the case body outer face in the side direction can be shortened. 
   According to the invention, by arranging the ring-like packing for sealing the interval between the pipe and the push button within the range of the height of the coil spring for urging the push button and concentrically with the coil spring, the portable apparatus and the portable timepiece capable of shortening the length in the axial direction of the push button can be provided. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front view showing a wristwatch of a first embodiment of the invention. 
       FIG. 2  is a sectional view taken along a line F 2 -F 2  in  FIG. 1 . 
       FIG. 3  is a sectional view in correspondence with  FIG. 2  showing a wristwatch of a second embodiment of the invention. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   A first embodiment of the invention will be explained in reference to  FIG. 1  and  FIG. 2 . 
   In  FIG. 1 , notation  11  designates a portable apparatus, for example, a portable timepiece, specifically, a wristwatch of a digital display type. The wristwatch  11  includes a timepiece exterior  12  constituting an apparatus exterior. As shown by  FIG. 2 , necessary members of the wristwatch  11 , for example, a liquid crystal display plate  13 , a circuit module such as a drive module  14  for controlling a display of a liquid crystal, a lamp (not illustrated), a battery (not illustrated) as a power source, and the like are contained inside of the timepiece exterior  12 . 
   The drive module  14  includes, for example, 4 pieces (only 1 piece is illustrated in  FIG. 2 ) of contacts  15  each comprising a leaf spring or the like, and the contacts  15  are projected from an outer periphery of the drive module  14 . By pushing the contacts  15  by a push button mentioned later, functions provided to the respective push buttons are achieved by the drive module  14 . For example, a push button  25  at the upper right in  FIG. 1  is assigned with a function of start/stop, a push button  25  at the lower right in  FIG. 1  is assigned with a function of turning on/turning off a lamp, a push button  25  at the upper left in  FIG. 1  is assigned with measurement of lap time, and a push button  25  at the lower left is assigned with a function of switching a display mode of a liquid crystal display plate. 
   As shown by  FIG. 2 , the timepiece exterior  12  is formed by mounting cover glass  22  for viewing therethrough the liquid crystal display plate  13  in a liquid tight manner to a front face of a case body  21  made in a ring-like shape by a metal of stainless steel, titanium or the like and mounting a case back  23  made of a metal, a synthetic resin or the like in a liquid tight manner to a back face of the case body  21 . 
   A constitution of mounting push buttons  25  at predetermined portions of the timepiece exterior  12 , for example, at four portions of the case body  21  constituting a side wall of the timepiece exterior  12  will be explained. The respective push buttons  25  and constitutions of mounting these to the case body  21  are the same, and therefore, here, a constitution of mounting the push button  25  for start/stop function will representatively be explained in reference to  FIG. 2 . 
   The case body  21  is formed with a recess portion  31  opened to a case body outer face (exterior outer side face)  21   a  thereof and formed with a through hole  32  penetrating an innermost wall  21   b  of the recess portion  31 . Both of the recess portion  31  and the through hole  32  of a diameter smaller than a diameter of the recess portion  31  are constituted by a circular shape and provided concentric with each other. A thickness A from a case body inner face (exterior inner side face)  21   c  of the case body  21  at which one end of the through hole  32  is opened to the case body outer face  21   a  is set by a total value of a depth B of the recess portion  31  and a thickness C of the innermost wall  21   b . Further, notation D designates a thickness of a case body front face around the cover glass  22 , and the case body front face thickness D is defined by a width dimension reaching the case body outer face  21   a  from a cover glass fitting portion. 
   A pipe  35  made of a metal of stainless steel, titanium or the like is fixed to the case body  21 . The pipe  35  comprises an inserting cylinder portion (inner cylinder portion)  36  and an outwardly arranged cylinder portion (outer cylinder portion)  37  integral therewith. The outwardly arranged cylinder portion  37  is formed by an innermost wall contact portion  37   a  having a spring receiving face  37   b  and a cylinder end portion  37   c  projected in a direction reverse to a direction of projecting the inserting cylinder portion  36  and extending orthogonally from the spring receiving face  37   b . Although not limited to the following constitution, according to this embodiment, in view of a relationship of making an inner peripheral face of the inserting cylinder portion  36  and an inner peripheral face of the outwardly arranged cylinder portion  37  flush with each other, the innermost wall contact portion  37   a  constitutes a ring-like projected portion projected from an outer periphery of the outwardly arranged cylinder portion  37  and continuous in a peripheral direction. 
   The pipe  35  is inserted to be attached to the case body  21  by press-fitting and penetrating the inserting cylinder portion  36  through the through hole  32  from an outer side of the case body  21  until the innermost wall contact portion  37   a  is brought into contact with the innermost wall  21   b . Thereby, the outwardly arranged cylinder portion  37  is disposed at a center portion of the recess portion  31  and arranged at an outer portion of the case body  21 . 
   The cylinder end portion  37   c  of the pipe  35  is attached with a packing  41  in the form of a packing ring for waterproof and dustproof at a ring-like groove formed to be opened at an inner peripheral face thereof. The packing ring  41  is formed in a ring-like shape by a rubber type or plastic type material capable of being deformed elastically. 
   The push button  25  includes a shaft portion  26 , a drawout preventing member  27  and an operating head  28 . The shaft portion  26  and the operating head  28  are an integrally molded product of a metal or a synthetic resin and the drawout preventing member  27  is a separate member. 
   The shaft portion  26  has a shape of a circular pillar and is slidably disposed in the pipe  35 . The drawout preventing member  27  comprising a stop member such as a stop ring or the like is attached to one end portion in a longitudinal direction of the shaft portion  26  disposed at an inner portion of the case body  21 . The drawout preventing member  27  has a size capable of engaging an end face of the inserting cylinder portion  36  projected to the inner portion of the case body  21  to prevent withdrawal of the shaft portion from the pipe  35 . 
   The operating head  28  is integrally provided to the other end in the longitudinal direction of the shaft portion  26  disposed at an outer portion of the case body  21 . The operating head  28  has a cap-like shape and a peripheral wall  28   a  thereof is configured to cover the cylinder end portion  37   c  of the outwardly arranged cylinder portion  37  and fit in the recess portion  31 . 
   The push button  25  is attached to the case body  21  by inserting the shaft portion  26  to the pipe  35  to penetrate from the outer side of the case body  21 , thereafter, attaching the drawout preventing member  27  at the front end portion of the shaft portion  26  projected to the inner portion of the case body  21 . The packing  41  is brought into close contact with a peripheral face of the shaft portion  26  penetrated to the pipe  35  and an interval of the pipe  35  and the push button  25  is sealed by the packing  41 . 
   The push button  25  is urged in an outer direction of the timepiece exterior  12 , specifically, in an outer side direction of the case body  21  by a coil spring  45 . For that purpose, the coil spring  45  is interposed between the spring receiving face  37   b  and an inner face of the operating head  28  at one end thereof. The coil spring  45  is brought into a state of being more or less compressed and can further be compressed by pushing the push button  25 . The cylinder end portion  37   c  of the outwardly arranged cylinder portion  37  is inserted between a portion of the coil spring  45  on a side of the spring receiving face  37   b  and the shaft portion  26 . Thereby, the cylinder end portion  37   c  is opposed to the coil spring  45 . 
   In the wristwatch  11  having the above-described constitution, in an ordinary state in which the push button  25  is not used, such as when carrying the wristwatch  11  or the like, as shown by  FIG. 2 , the push button  25  is held in an outward position by the urging force of the coil spring  45  in readiness to be pushed inwardly to an inward position to engage the contact  15 . 
   In this state, by the urging force (spring force) of the coil spring  45 , the drawout preventing member  27  engages with a front end portion of the inserting cylinder portion  36  and the push button  25  is maintained in its outward position and prevented from being detached. In this state, an opening end portion of the peripheral wall  28   a  of the operating head  28  fits in an opening portion of the recess portion  31 , and gaps G enabling to push the push button  25  respectively between the innermost wall  21   b  and the opening end of the peripheral wall  28   a  of the operating head  28  and between the cylinder end portion  37   c  of the outwardly arranged cylinder portion  37  and the inner face of the operating head  28  are ensured. A pushing stroke of the push button  25  is defined by the gaps G. Further, the push button  25  is positioned such that the front end  26   c  of the shaft portion  26  of the push button  25  is proximate to and opposed to the contact  15  of the drive module  14  by engagement of the drawout preventing member  27  with the inserting cylinder portion  36 . Further, a foreign matter of water, sand, dust or the like can be restrained from invading the inner portion of the case body  21  by the packing  41  interposed between the pipe  35  and the push button  25 . 
   An operation of pushing the push button  25  is permitted by the gaps G, and therefore, when the push button  25  is pushed from the outer side of the case body  21  against the spring force of the coil spring  45 , the front end  26   c  of the shaft portion  26  pushes the contact  15 . Thereby, the drive module  14  is operated to achieve the function assigned to the push button  25 . Thereafter, as the push button  25  is released from being pushed, the push button  25  is pushed back by the spring force of the coil spring  45 . 
   According to the wristwatch  11  having the above-described constitution, the packing  41  is attached to the cylinder end portion  37   c  of the pipe  35  at a region where the coil spring  45  encircles and overlies the cylinder end portion  37   c . As illustrated in  FIG. 2 , when viewed in a direction normal to the axis of the shaft portion  26 , the coil spring  45  and the packing ring  41  overlap one another. Therefore, the packing  41  assigned with waterproof or the like is arranged between one end and other end of the coil spring  45 , in other words, within a range of a height L of the coil spring  45  and concentrically with the coil spring  45 . 
   According to such an arrangement of the packing  41  and the coil spring  45  around the pushbutton  25 , it is not necessary to ensure a region for attaching the packing  41  at the shaft portion  26  of the push button  25  at a position of being shifted from a shaft portion region in correspondence with the height L of the coil spring  45  in an axial direction as in a case of aligning the coil spring  45  and the packing  41  in the axial direction of the shaft portion  26  of the push button  25 . In other words, as shown by  FIG. 2 , a region  26   b  for attaching the packing  41  is provided within a shaft portion region  26   a  in correspondence with the height L of the coil spring  45 . Therefore, a length in the axial direction of the push button  25  can be shortened by an amount of a length R in correspondence with a width dimension of the packing  41 . 
   Thereby, under a condition in which the thickness D of the case body front face is made to be the same as that in the background art, a dimension E for projecting the push button  25  from the case body outer face  21   a  can be shortened, conversely, under a condition in which the projected dimension E is made to be the same as that of the background art, the thickness D of the case body front face can be narrowed. Further, in a case of being constituted as in the latter, small-sized and light-weighted formation of the case body  21  can be realized and the wristwatch  11  of a design in which a voluminous feeling of the thickness D of the case body front face is small can be constituted. 
     FIG. 3  shows a second embodiment of the invention. The second embodiment is the same as the first embodiment except as explained below, and therefore, a description of the elements of the second embodiment that are the same as those of the first embodiment will be omitted. 
   According to the second embodiment, the packing  41  arranged concentrically with the coil spring  45  is attached to the shaft portion  26 . In an ordinary state of pushing back the push button  25  by the coil spring  45 , the packing  41  is attached within the shaft portion region  26   a  in correspondence with the height L of the coil spring  45 , and the packing  41  is brought into close contact with the inner periphery of the cylinder end portion  37   c  of the pipe  35  inserted between the coil spring  45  and the shaft portion  26 . Further, the opening portion of the cylinder end portion  37   c  is provided with a taper face, thereby, insertion of the shaft portion  26  attached with the packing  41  to inside of the pipe  35  is facilitated. 
   Further, according to the second embodiment, the thickness of the innermost wall  21   b  of the recess portion  31  is made to be thinner than the gap G enabling to push the push button  25 , and the thickness of the innermost wall contact portion  37   a  is made to be equal to or thinner than the thickness of the innermost wall  21   b . The second embodiment is the same as the first embodiment except as explained above. 
   Therefore, according to the second embodiment, the problem of the invention can be resolved by the reason explained in the first embodiment. In addition thereto, the second embodiment is more excellent than the first embodiment in the following points. 
   First, since the thickness C of the innermost wall  21   b  of the recess portion  31  is made to be thinner than the gap G enabling to push the push button  25 , and therefore, the length of the shaft portion  26  of the push button  25  can be made to be shorter than that of the push button used in the first embodiment in accordance therewith. Further, also the thickness of the innermost wall contact portion  37   a  is made to be thin, and therefore, the length of the shaft portion  26  can further be shortened also in this respect, and the projected width of the push button  25  projected from the case body outer face  21   a  to the outer side direction can be shortened in accordance therewith. 
   Therefore, under a condition in which the size of the gap G is made to be the same as the gap according to the first embodiment, the case body front face thickness D reaching the case body outer face  21   a  from the cover glass fitting portion of the case body  21  can be narrowed. Thereby, in comparison with the first embodiment, further small-sized and light-weighted formation of the case body  21  can be realized, and the wristwatch  11  of a design in which the volume feeling of the case body front face thickness D is further small can be constituted. 
   Second, by attaching the packing  41  to the shaft portion  26 , a wall thickness for holding the packing  41  is not needed in the outwardly arranged cylinder portion  37  of the pipe  35 . In accordance with thinning the wall thickness of the outwardly arranged cylinder portion  37  in this way, a maximum diameter of the outwardly arranged cylinder portion  37  defined by the innermost wall contact portion  37   a  can be reduced. Therefore, despite that the diameter of the shaft portion  26  is the same as that in the case of the first embodiment, the small diameter coil spring  45  can be used and the operating head  28  of the push button  25  can be formed by a small diameter in accordance therewith. 
   Further, in a case of achieving small-diameter formation of the push button  25  in this way, also the diameter of the formed recess portion  31  of the case body  21  is reduced, and therefore, the thickness (height) of the total of the case body  21  is made to be smaller than that of the first embodiment and thin-sized formation of the wristwatch  11  can be achieved. 
   Further, although according to the above-described respective embodiments, waterproof is achieved between the pipe  35  and the shaft portion  26  of the push button  25 , in place thereof, waterproof can also be achieved between the pipe  35  and the operating head  28  of the push button  25 . In this case, the cylinder end portion  37   c  of the outwardly arranged cylinder portion  37  of the pipe  35  may be inserted between the outer periphery of the portion of the coil spring  45  on the side of the spring receiving face  37   b  and the peripheral wall  28   a  of the operating head  28  and the packing  41  brought into close contact with the inner face of the peripheral wall  28   a  may be attached to the cylinder end portion  37   c  at the outer peripheral portion of the cylinder end portion  37   c . Although according to the constitution, the packing  41  of the diameter larger than those of the respective embodiments needs to be used, the constitution is preferable in that waterproof/dustproof can be carried out for the coil spring  45 . 
   The invention is not restricted to the respective embodiments but is applicable to a stopwatch, a portable apparatus of, for example, a portable telephone, a portable type information terminal or the like other than the portable timepiece.