Abstract:
A structure of a rotating mechanism for a watch case having a time display section, comprising a case body internally accommodating the time display section and having a lower opening, a back cover fitted into the lower opening of the case body, a retining ring secured to a lower portion of the case body, and a band attaching base engaging with the case body by being clamped between the retaining ring and the case body. The case body is adapted to rotate with respect to the band attaching base.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a structure of the watch case wherein a case body having a time display section rotates with respect to a band attaching base, particularly a rotating mechanism for the watch case. 
     2. Prior Art 
     A conventional structure of a rotating case of this type is disclosed in the specification of Japanese Utility Model Application Laid-Open No. 59-98385. 
     As shown in FIG. 19, the conventional structure includes an upper middle 10 internally accommodating a time display section having a dial, hands, movement and the like, a lower middle 12 to which a band 14 is attached, and a back cover 16 screwed securely and water-tightly into the upper middle 10 via a packing 18. The lower middle 12 is rotatably sandwiched between the upper middle 10 and the back cover 16. Further, the packing 20 is interposed between the back cover 16 and the lower middle 12 to get a suitable regulation of the rotation by friction produced between the back cover 16 and the packing 20. 
     In the prior art, in order to position the packing 20, a recess 16a is formed in the outer circumferential surface of the back cover 16. As a result, a shape of the back cover 16 becomes complicated and its height becomes higher. Further, the back cover 16 cannot be used in common in other watch cases, thus making it impossible to achieve standardization. 
     As shown in FIG. 20, the conventional structure further includes a hole 10a provided at a lower surface of the upper middle 10, a spring 22 adapted in the hole 10a, a ball 23 pressed by the spring 22 in the direction of the lower middle 12 and radial grooves 12a. The radial grooves 12a are formed at the upper face of the lower middle 12 as shown in FIG. 21. The ball 23 and the grooves 12a are engaged, therefore, when the upper middle 10 is rotated the feeling of a click operation is produced. 
     In the conventional structure, the upper middle 10 is able to rotate through 360° with respect to the lower middle 12. Consequently, when rotating the upper middle 10, the 12:00 position becomes indistinct. Thus, it is necessary to make the 12:00 indicator to stand out. 
     A further problem is that it is difficult to select a position at which the upper middle 10 is to be stopped in a case where the click groove structure is operated during the operation of a vehicle or the like. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is the primary object of this invention to provide a structure of a watch case having a rotating mechanism without changing the shape of a back cover. 
     It is another object to provide a structure of a watch case, which structure produces good operational feeling and reliable operation. 
     In keeping with the principles of the present invention, the above-mentioned objects are accomplished by a structure of a rotating mechanism for a watch case, wherein a structure of a rotating mechanism for a watch case having a time display section, comprising: a case body internally accomodating said time display section and having a lower opening; a back cover fitted into said lower opening of said case body; a retaining ring secured to a lower portion of said case body; and a band attaching base engaging with said case body by being clamped between said retaining ring and said case body, said case body being adapted to rotate with respect to said band attaching ring. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and features of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a sectional view illustrating a first embodiment of the present invention; 
     FIG. 2 is a plan view of a polygonal spring shown in FIG. 1; 
     FIG. 3 is a sectional view illustrating a modification of the first embodiment shown in FIG. 1; 
     FIGS. 4 and 5 show examples of a packing shown in FIG. 3; 
     FIG. 6 is a sectional view illustrating a second embodiment of the present invention; 
     FIG. 7 is a sectional view illustrating a modification of the second embodiment shown in FIG. 6; 
     FIG. 8 is a sectional view illustrating a third embodiment of the present invention; 
     FIGS. 9 and 10 are plan and bottom views of a band attaching base and a case body, respectively, according to a modification of each of the abovementioned embodiments of the present invention; 
     FIGS. 11 and 12 are partial sectional views illustrating the 12:00 position and 6:00 position, respectively, when the band attaching base and case body shown in FIGS. 9 and 10 are fitted together; 
     FIGS. 13 and 14 are plan and bottom views of the band attaching base and case body according to another modification of at least the first embodiment; 
     FIG. 15 is a partial sectional view illustrating the 12:00 position when the band attaching base and case body shown in FIGS. 13 and 14 are fitted together; 
     FIG. 16 is a partial sectional view illustrating still another modification of at least the first embodiment; 
     FIG. 17 is a sectional view illustrating a back cover which can be used for the structure of the present invention; 
     FIG. 18 is a sectional view illustrating another back cover which can be used for the structure of the present invention; 
     FIG. 19 is a sectional view illustrating a rotating mechanism of a conventional rotating case; 
     FIG. 20 is a sectional view illustrating the structure of a conventional rotating case; and 
     FIG. 21 is a plan view of a lower middle shown in FIG. 20. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 is a sectional view illustrating a first embodiment of the present invention. Numeral 30 denotes a case body internally accommodating a watch display section and having an outwardly facing annular step 30a formed at a lower portion thereof. 
     Numeral 32 denotes a back cover fitted into a lower opening 30b of the case body 30 by being screwed into the opening 30b. 
     Numeral 34 denotes a retaining ring having a mounting portion 34c clamped between the step 30a of case body 30 and a peripheral portion 32a of the back cover 32. The outer circumferential portion of the retaning ring 34 is provided with a outwardly facing annular step 34a. 
     Numeral 36 denotes a ring-shaped band attaching base having a band 38 attached thereto. The band attaching base 36 has an engaging portion 36a formed on an inner circumferential side thereof and rotatably sandwiched between the step 34a of the retaining ring 34 and a horizontal surface 30c of the case body 30. The band attaching base 36 also has an annular groove 36b formed at an inner circumferential surface 36c thereof. 
     Numeral 40 denotes a polygonal spring as shown in FIG. 2. The polygonal spring 40 is disposed in the annular groove 36b and comes in contact with a vertical surface 34b of the step 34a and an inner surface of the annular recess 36b. 
     Numeral 42 denotes a packing compressed by the case body 30, back cover 32 and retaining ring 34, thereby improving the watertightness of the interior of the watch case. 
     When the user holds the case body 30 and rotates that, the back cover 32 and retaining ring 34 are rotated together with the case body 30. Then, the rotation of the retaining ring 34 is suppressed and controlled by the spring 40 stretching between the retaining ring 34 and band attaching base 36. 
     In this embodiment, the case body 30 and band attaching base 36 are fitted together in a freely rotatable manner by the retaining ring 34. This makes it possible to simplify the structure of the back cover 32 and to employ a back cover which is commonly used. 
     FIG. 3 shows a modification of the structure shown in FIG. 1. Like elements corresponding to those of FIG. 1 are indicated by like numerals. 
     In this modification, the case body 30 has an annular groove 30d formed at the horizontal surface 30c of the step 30a, and also an annular groove 34c is provided with the vertical surface 34b of the retaining ring 34 together with omitting the annular groove 36b of the band attaching base 36. 
     Further, packings 44 ans 46 are employed. The packing 44 is received in the annular groove 30d of the case body 30 and is compressed between the case body 30 and an upper surface 34d of the retaining ring 34. The packing 46 is received in the annular groove 34c of the retaining ring 34 and is compressed betweeen the retaining ring 34 and the inner circumferential surface 36c of the band attaching base 36. 
     In this modification, the packing 44 produces a large frictional force between the case body 30 and retaining ring 34, thereby acting substantially integrate the case body 30 and retaining ring 34. Further, a frictional force is produced between the packing 46 and band attaching base 36, so that the packing 46 acts to suitably suppress rotation. 
     It is of course possible to use the polygonal spring 40 in place of the packing 46. Furthermore, besides using an O-ring such as shown in FIG. 3 as the packing 46, it is able to use a packing having a bead-shaped or C-shaped cross section, as shown in FIGS. 4 and 5, respectively. 
     In the present modification, the rotation of the case body 30 is controlled by the packing 46 which is provided on the side of the rotating ring 36. 
     FIG. 6 is a sectional view illustrating a second embodiment of the present invention. Numeral 50 denotes a case body the lower circumferential porti on of which is provided with a step 50a having a vertical surface 50b provided with an annular groove 50c. The case body 50 also has an annular recess 50d formed at the lower surface thereof and has an inwardly facing step 50e formed on its lower, inner circumference. 
     Numeral 52 denotes a back cover fitted into a lower opening 50f of the case body 50 as being screwed into the opening. 
     Numeral 54 denotes a retaining ring of generally Z-shaped cross section suitable for the annular recess 50d of case body 50 and having a mounting portion 54a fixedly clamped between the peripheral portion 52a of back cover 52 and the case body 50 and having an engaging portion 54b projecting below the step 50a of case body 50. 
     Numeral 56 denotes a ring-shaped band attaching base having a band 58 attached thereto. The band attaching base 56 has an engaging portion 56a fitted into the step 50a of case body 50 and sandwiched between a horizontal surface 50g of the case body 50 and the engaging portion 54b of retaining ring 54, whereby the band attaching base 56 is rotatably attached to the case body 50. 
     Numeral 60, 62 designate packings. The packing 60 is received in the step 50e of case body 50 and is compressed between the case body 50 and the peripheral portion 52a of back cover 52 to assure the waterproof property of the interior of the case. The packing 62 is received in the annular groove 50c of case body 50 and acts to produce a suitable frictional force between the case body 50 and the inner circumferential surface 56b of the band attaching base 56. 
     As shown in FIG. 7, the step 50e of case body 50 may be modified into a surface 50h continuous with the recess 50d, and the packing 60 may be so arranged as to be compressed by the surface 50h, the peripheral portion 52a of the back cover 52 and the inner circumferential surfaace 54c of the retaining ring 54. It is also possible to use the polygonal spring 40 in place of the packing 46. 
     The case body 50 of the present embodiment is also attached as illustrated in the foregoing arrangement so as to be freely rotatable with respect to the band attached base 56. Rotation of the case body 50 is controlled by the packing 62 which is provided on the side of the case body 50. 
     FIG. 8 is a sectional view illustrating a third embodiment of the present invention. Numeral 70 denotes a case body having an outwardly facing first annular step 70a provided at the lower circumferential portion. The case body 70 also has an outwardly facing second annular step 70c underlying the step 70a, and a screw hole 70e is formed at the horizontal surface 70d of the second annular step 70c. The lower circumferential portion of the case body 70 is also provided with an inwardly facing third annular step 70f. 
     Numeral 72 denotes a back cover fitted into a lower opening of the case body 70 with its peripheral portion 72a compressing a packing 80 received in the step 70f of the case body 70. 
     Numeral 74 designates a retaining ring of generally L-shaped cross section having an outwardly facing step 74a formed at the lower part of the outer circumference thereof. The step 74a has a vertical surface 74b provided with an annular groove 74c accommodating a packing 82. The retaining ring 74 also has an engaging portion 74d in contact with the horizontal surface 70d of the case body 70. The engaging portion 74d has a through-hole 74e formed at a position corresponding to the screw hole 70e of case body 70. 
     Numeral 76 denotes a ring-shaped band attaching base having a band 78 attached thereto. An engaging portion 76a thereof is clamped between the horizontal surface 70b of case body 70 and the step 74a of retaining ring 74, whereby the band attaching base 76 is attached to the case body 70 in such a manner that the packing 82 is pressured by an inner circumferential surface 76b of the band attaching base 76. 
     Numeral 84 denotes a screw that is screwed into the screw hole 70e of the case body 70 via the through-hole 74e of retaininf ring 74. 
     Since the retaining ring 74 in the present embodiment is attached to the case body 70 by the screw 84, the arrangement is such that the case body 70 can be detached from the band attaching base 76 without removing the back cover 72. 
     FIG. 9 is a plan view of a band attaching base according to a modification of each of above-mentioned embodiments of the present invention, and FIG. 10 is a bottom view of a case body according to this modification, with like parts bearing the same reference numerals as those used in FIG. 1. The present modification includes adding a click groove structure to the case body rotating structure such as structures shown in FIGS. 1 to 8. Accordingly, the modification based on the first embodiment shown in FIG. 1 is only described as an example. 
     The band attaching base 36 illustrated in FIG. 9 has a generally ring-shaped configuration and is provided with band attaching portions 36d,36e at the 12:00 and 6:00 positions, respectively. 
     The case body 30 shown in FIG. 10 also has a ring-shaped configuration. The band attaching base 36 and case body 30 are fitted together by the retaining ring 34, described above, so as to be freely rotatable. 
     The band attaching base 36 has an upper surface 36f which opposes the case body 30 when the band attaching base 36 and case body 30 are fitted together. The band attaching base 36 also has a plurality of radially extending click grooves 36g and a rotation limiting groove 36h provided at the 12:00 and 6:00 positions, respectively, and formed along the contour of the band attaching base 36. 
     As shown in FIG. 9, the click grooves 36g and rotation limiting groove 36h are provided over a range extendig 30° to either side of the 12:00 position and 6:00 position. 
     A pivot 90 and a pin 92 are implanted in the lower surface 30f of the case body 30 opposing the band attaching base 36 and fitted into the click grooves 36g and rotation limiting 36h of the band attaching base 36 when the case body 30 and band attaching base 36 are assembled. 
     FIGS. 11 and 12 are partial sectional views illustrating the 12:00 position 6:00 position, respectively, when the band attaching base 36 and case body 30 are fitted together. 
     A hole 30e which opens to the side of the lower surface 30c is provided in the case body 30. The pivot 90 is press-fitted into the hole 30e. The pivot 90 is composed of a pipe 90a, a spring 90b accommodated in the pipe 90a, and a ball 90c pushed by the spring 90b. The ball 90c projects from the opening of the hole 30e in case body 30. Accordingly, when the case body 30 is rotated, the ball 90c pushed by the spring 90b falls into the click grooves 36g and rises up pn the surface 36f of the band attaching base 36 to produce the feeling of a click operation. 
     As shown in FIG. 12, a hole 30f opening to the side of the lower surface 30c is provided in the case body 30 at the 6:00 position. The pin 92 is pressfitted into the hole 30f and projects into the rotation limiting groove 36h provided in the band attaching base 36. When the case body 30 is rotated and the angle of rotation reaches a limit value, the pin 92 comes into abutting contact with the edge of the rotation limiting groove 36h at one end thereof. 
     In this modification, it is possible to set the case body to the optimum position very easily during the driving of a vehicle or the like without visually confirming position. Furthermore, the region in the vicinity of the band attaching portions of the band attaching base is only utilized for providig the click groove, thus it is possible to reduce a thickness of the portion other than the band attaching portions. 
     FIG. 13 is a plan view of the band attaching base according to another modification of at least first embodiment, and FIG. 14 is a bottom view of a case body according to this modification. Like elements corresponding to those of FIGS. 9 and 10 are indicated by like numerals. 
     As in the above-mentioned modification, the band attaching base 30 shown in FIG. 13 has band attaching portions 36d, 36e and click grooves 36g. A rotation limiting groove 36i, which acts in the same manner as the rotation limiting groove 36h shown in FIG. 9, is provided along the periphery of the click grooves 36g of the present modification and is shallower in depth than the click grooves 36g. 
     A case body 30 shown in FIG. 14 is provided only with a pivot 90 at the 12:00 position. 
     As shown in FIG. 15, in this modification, the ball 90c and the end portion of the pipe 90a project from the opening of the hole 30e. As a result, when the case body 30 is rotated, the ball 90c falls into the click grooves 36g of the band attaching base 36 and rises up onto the floor surface of the rotation limiting groove 36i to produce the feeling of a click operation. When the angle of rotation of case body 30 reaches a limit value, the end portion of pipe 90a of pivot 90 projecting from the hole 30e comes into abutting contact with the edge of the rotation limiting groove 36i, thereby limiting rotation. 
     FIG. 16 is a partial sectional view illustrating still another modification of at least first embodiment shown in FIG. 1. In this modification, a surface such as an outer circumferential surface 30g or lower surface 30h of a case body 30 that opposes a band attaching base 36 is provided with click grooves 30i that extend over an angle of rotation having a maximum value of 60°. Further, a rotation limiting groove is formed on the outer circumferential surface 30g or lower surface 30h, just as in above-mentioned modifications. In this modification, the pivot 90 is press-fitted into a hole 36j formed in the band attaching base 36. Then, the feeling of a click operation is produced by the pivot 90. 
     According to all of the above-mentioned embodiments, it is possible to employ a back cover which is used for the other watch case. Therefore, it is possible to employ a specific back cover as described hereinbelow. 
     FIG. 17 is a sectional view illustrating a back cover which can be used for the structure of the present invention. 
     A back cover body 100 has an upper surface 100a to which a piezoelectric element 102 is affixed to provide the back cover with a piezoelectric buzzer function. The back cover body 100 also has a recess 100b formed on a lower surface thereof. A sound diaphragm 104 made of metal and having a sounf emitting hole 104a is attached to the back cover body 100 by being press-fitted into the back cover so as to cover the recess 100b. It is possible to attach the sound diaphragm 104 to the back cover by bonding , brazing or welding. 
     FIG. 18 showa the sound diaphragm 110 attached via a waterproof packing 112 to the back cover body 106 having the piezoelectric element 108 affixed thereto. 
     Accordig to the present invention, the case body and band attaching base are fitted together in a freely rotatable manner by the retaining ring. This makes it possible to simplify the structure of the back cover and to employ a back cover which is used for the other watch case. In addition, the retaining ring can also be mounted on a band attaching base having different specifications merely by modifying the retaining rig without altering the case body or back cover.