Patent Publication Number: US-8536474-B2

Title: Rotary switch

Description:
TECHNICAL FIELD 
     The present invention relates to a rotary switch in which an operation shaft rotates to open/close switches between a plurality of terminals. 
     BACKGROUND ART 
     Recent mobile electronic devices are often requested to have various functions. A rotary switch is used as one means for operations of the functions. Thus, there are various requests for the rotary switch, such as the number of switches, relative timings (relative angle positions) of opening/closing (on/off) of each switch, combination of opening/closing of a plurality of switches, or operation feeling (click feeling) correspondingly to various operations. 
       FIG. 7  shows an example of a conventional rotary switch disclosed in Patent literature 1. In this conventional example, a circular housing recess  230  is formed at a center of a substantially square insulation body  110 , and there are formed on a floor surface of the housing recess  230 , an upright support shaft  240  at a center thereof, a ring-shaped common contact piece  290  surrounding the support shaft  240 , and a plurality of fixed contact pieces  220  circumferentially arranged outside the common contact piece  290 . The common contact piece  290  and the fixed contact pieces  220  are extended to a side edge of the insulation body  110  to form external terminals. 
     A rotating operation knob  120  includes an operation shaft  570 , and an annular click plate  440  integrally formed with the operation shaft  570 , and steps  490  and recesses  510  are alternately formed at regular angular intervals in an upper surface of the annular click plate  440 . A rotating contactor  130  is secured to a lower surface of the annular click plate  440 , and the rotating operation knob  120  is rotatably supported by the support shaft  240  and housed in the housing recess  230  in the insulation body  110 . 
     The circular rotating contactor  130  formed by stamping a spring metal plate has a window at a center thereof, and a forked common slider  790  is formed to protrude on opposite sides of the support shaft  240  in the window. Each tip of the common slider  790  is brought into elastic contact with the common contact piece  290 . Middle parts of two arcuate contact pieces formed by circumferentially slitting a peripheral edge of the rotating contactor  130  protrude downward to form switching contacts  680 , and the switching contacts  680  slide on the arranged fixed contact pieces  220  and are brought into elastic contact with any one of the fixed contact pieces  220 . 
     A ring-shaped leaf spring  140  is placed on the annular click plate  440  of the rotating operation knob  120 . The ring-shaped leaf spring  140  has fixed terminals  830  extended outward from an outer peripheral edge at two points on a diameter thereof. Each fixed terminal  830  is bent 90 degrees downward at an intermediate part, and inserted and secured into an engaging hole  250  formed in each of opposite corners in an upper surface of the insulation body  110 . 
     The ring-shaped leaf spring  140  has engaging protrusions  840  formed to protrude downward at two points on a diameter perpendicular to the diameter passing through the two fixed terminals  830 , the engaging protrusions  840  climb the steps  490  in the annular click plate  440  against a spring force by rotation of the rotating operation knob  120 , and fit in the recesses  510  by the spring force, thereby causing click feeling in a rotating operation of the rotating operation knob  120 . 
     A substantially square metal case  150  is configured so that the operation shaft  570  protrudes outward through a shaft hole  920  formed at a center thereof, closes the housing recess  230  in the insulation body  110  from above the ring-shaped leaf spring  140  and is secured to the insulation body  110 . 
     PRIOR ART LITERATURE 
     Patent Literature 
     
         
         Patent literature 1: Japanese Patent Application Laid-Open No. 2008-166158 
       
    
     SUMMARY OF INVENTION 
     Problems to be Solved by the Invention 
     In the conventional rotary switch, the operation shaft  570  protruding outward is rotated to bring the common contact piece  290  into conduction with selected one of the fixed contact pieces  220 , and provide conduction between two corresponding external terminals. The common contact piece  290  is always brought into conduction with only one fixed contact piece  220 . The number of the fixed contact pieces  220  in the circumferential direction, the number of fixed contact pieces  220  that can be selected by changing a circumferential length (angular width), and a rotating angular width of the rotating operation knob  120  that maintains conduction with the same fixed contact piece can be set to desired values, but in the example in  FIG. 7 , the common contact piece  290  cannot be simultaneously brought into conduction with a plurality of the fixed contact pieces  220 . If circumferential angular positions of the two switching contacts  680  are displaced, the common contact piece  290  can be simultaneously brought into conduction with a plurality of the fixed contact pieces  220 . However, there is limitation in variety of shapes of the fixed contact pieces  220  that can be placed on the same floor surface and arrangement patterns, and complicated functional operations required of mobile electronic devices cannot be sufficiently accommodated. The present invention has an object to provide a rotary switch that can be designed to have various combinations of opening/closing of a plurality of switches, relative angular positions of opening/closing, or angular widths in a closed state so as to accommodate various functional operations. 
     Means to Solve the Problems 
     The present invention provides a rotary switch including: a rotor including a disk part, and a rotation shaft having a shaft hole formed at a center thereof, and insert molded so that a first metal contact piece having a predetermined number of contact regions each having a predetermined angular width in each of one or more first annular zones defined by a plurality of first concentric circles and a second metal contact piece having a predetermined number of contact regions each having a predetermined angular width in each of one or more second annular zones defined by a plurality of second concentric circles are stacked in the disk part, and the contact pieces are exposed in one surface and another surface of the disk part; a first holder having a plurality of first elastic contacts in elastic contact with the one surface of the disk part in the one or more first annular zones; a second holder having a plurality of second elastic contacts in elastic contact with the other surface of the disk part in the one or more second annular zones; and a rotating operation shaft that is inserted through the first holder, the rotation shaft of the rotor, and the second holder, and is configured to rotate the rotor. 
     Effects of the Invention 
     According to the present invention, contact piece regions within 360 degrees can be separately determined in radially different annular regions in upper and lower surfaces of the disk part of the rotor. This provides flexibility in design of opening/closing angular ranges of a plurality of switches and relative timings as requested. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a first embodiment of a rotary switch according to the present invention. 
         FIG. 2A  is a perspective view of a click spring and a click spring support plate to which the click spring has not been mounted. 
         FIG. 2B  is a perspective view of the click spring support plate to which the click spring has been mounted. 
         FIG. 3A  is a top view of a rotor; rotor. 
         FIG. 3B  is a sectional view of the rotor. 
         FIG. 3C  is a bottom view of the rotor. 
         FIG. 4A  shows a connection pattern of upper and lower contact pieces. 
         FIG. 4B  shows a slide contact piece formed by folding the connection pattern. 
         FIG. 5A  is a bottom view of a lower contactor holder. 
         FIG. 5B  is a top view of an upper contactor holder. 
         FIG. 6  is an exploded perspective view of a second embodiment of a rotary switch according to the present invention. 
         FIG. 7  is an exploded perspective view of a conventional rotary switch. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Now, embodiments of the present invention will be described in detail. 
     First Embodiment 
       FIG. 1  shows a first embodiment of a rotary switch according to the present invention. The rotary switch of the embodiment includes a rotating operation shaft  10 , a bearing  20 , a click disk  30 , a click spring  40 , a click spring support plate  50 , a lower contactor holder  60 , a rotor  70 , an upper contactor holder  80 , a cover  90 , and other components. 
     The rotating operation shaft  10  is formed of a metal rod into a cylindrical shape, and includes an operation part  11 , a holding part  12  coaxially extended from a tip of the operation part  11  and having a smaller diameter than the operation part  11 , and a driving part  13  coaxially extended from a tip of the holding part  12  and having a smaller diameter than the holding part  12 . An annular groove  12   a  is formed in an outer peripheral surface adjacent to a tip of the holding part  12 . At least one plane  13   a  formed by cutting in parallel with a central axis is formed in the driving part  13 . In the shown example, two planes parallel to each other are formed symmetrically with respect to the rotation center of the rotating operation shaft  10 . 
     The bearing  20  includes a cylinder part  21  having a mounting thread formed on an outer periphery, and a rectangular housing part  22  integrally formed with one end of the cylinder part  21 . At a center of the bearing  20 , a shaft hole  24  through which the holding part  12  of the rotating operation shaft  10  is rotatably inserted is formed through the cylinder part  21 . In an upper surface of the housing part  22 , positioning holes  22   a  are formed in one pair of opposite corners and securing holes  22   b  are formed in the other pair of opposite corners. Further, at a center of the upper surface of the housing part  22 , a circular click disk housing recess  23  is formed coaxially with the cylinder part  21 , and the shaft hole  24  concentrically passes through a bottom surface of the click disk housing recess  23 . A tip of the holding part  12  of the rotating operation shaft  10  inserted through the bearing  20  protrudes from the bottom surface of the click disk housing recess  23 , and a ring  12 A is fitted to the annular groove  12   a  at the tip for retaining the holding part  12 . 
     The click disk  30  includes a shaft part  31  at a center thereof, and in an upper surface outside the shaft part  31 , irregularities are circumferentially formed by radially extending ridges  32  like an annular click plate  40  in a conventional art in  FIG. 7 . The shaft part  31  has a shaft hole  33  through which a rotation shaft  71  of the rotor  70  is axially inserted, and an engaging key  34  protruding from one point on an inner periphery of the shaft hole  33  toward the center and axially extending. An end surface toward the center of the engaging key  34  is a plane brought into contact with and engaging the plane  13   a  of the driving part  13 . When the rotating operation shaft  10  is rotated, the plane  13   a  of the driving shaft part  13  inserted into the shaft hole  33  engages the end surface of the engaging key  34  to rotate the click disk  30 . 
     The annular click spring  40  is formed by stamping a spring metal plate, has engaging protrusions  41  protrude toward the click disk  30  at two points on one diameter of an annular part, and further has two fixed terminals  42  extended outward from two points on another diameter perpendicular to the former diameter and extended on extended lines of the diameter. The fixed terminal  42  is bent at an intermediate part substantially 45 degrees with respect to a plate surface toward a side opposite to the click disk  30 . The click spring  40  is substantially the same as that in the conventional art in  FIG. 7 . However, in the conventional art, the fixed terminals are bent 90 degrees, while the fixed terminals are bent 45 degrees in this embodiment, thereby reducing engagement of the click spring support plate  50  with a lock groove  55 , and thus reducing a thickness of the click spring support plate  50 . 
     The click spring  40  is mounted on a lower surface of the click spring support plate  50 .  FIGS. 2A and 2B  are perspective views showing before and after mounting of the click spring  40 . A set of the click spring  40  and the click spring support plate  50  in  FIG. 1  is shown rotated 180 degrees around a centerline  5 X. The click spring support plate  50  is rectangular like the housing part  22 , an annular recess  52  that receives the ring-shaped click spring  40  is formed in a lower surface of the click spring support plate  50 , and a shaft hole  51  is formed at a center. The shaft hole  51  has a diameter such that the rotation shaft  71  of the rotor  70  described later can be rotatably inserted through the shaft hole  51 . Two positioning holes  53   a  are formed adjacent to one side of the click spring support plate  50 , securing holes  53   b  are formed near one pair of opposite corners, and positioning protrusions  54  are formed on a lower surface near another pair of opposite corners. 
     The two fixed terminals  42  of the click spring  40  are inserted and locked into lock grooves  55  formed to extend from the securing holes  53   b  in the support plate  50  toward the center. In that state, the driving part  13  is inserted through the shaft hole  51  in the click spring support plate  50 , and mounted to the upper surface of the housing part  22  so as to close the click plate housing recess  23  housing the click disk  30  from above. At this time, the securing protrusion  54  of the click spring support plate  50  is press-fitted and secured in the positioning hole  22   a  in the upper surface of the housing part  22 . 
       FIG. 3A  is a top view of the rotor  70 ,  FIG. 3B  is a sectional view taken along the line  3 B- 3 B in  FIG. 3A , and  FIG. 3C  is a bottom view of the rotor  70  rotated 180 degrees around the line  3 B- 3 B in  FIG. 3A . The rotor  70  includes the rotation shaft  71 , a disk part  72  located in a middle in a length direction of the rotation shaft  71  and coaxial with the rotation shaft  71 , and a slide contact piece  7 C held by the disk part  72  integrally formed by insert molding. The rotation shaft  71  has a shaft hole  73  having the same sectional shape as the shaft hole  33  in the click disk  30 . Further, a notch part  74  is formed that is formed by axially cutting one arcuate part at a lower end of the rotation shaft  71  by a predetermined length from the lower end. With the notch part  74 , the rotation shaft  71  fits the engaging key  34  in the shaft hole  33  in the click disk  30  through the shaft hole  51 , and thus the rotation shaft  71  is inserted into the shaft hole  33   a  by the axial length of the notch part  74 . 
     The slide contact piece  7 C includes an upper contact piece  7 C 1  and a lower contact piece  7 C 2 , and is formed so that, as shown in  FIG. 4A , patterns of upper and lower contact pieces  7 C 1  and  7 C 2  obtained by stamping one metal plate and connected to each other are folded at a connecting part  7 Cc as shown in  FIG. 4B , and the lower contact piece  7 C 2  is placed on a lower side of the upper contact piece  7 C 1 . 
     In this embodiment, the upper and lower contact pieces  7 C 1  and  7 C 2  are formed to have patterns inscribed in a common circle C 1  shown by a broken line in  FIG. 4B , and define annular zones B 1 , B 2  and B 3  adjacent to each other and having widths between circles C 2 , C 3  and C 4  concentric with the circle C 1  and successively having smaller diameters, and patterns of contact pieces are previously determined having, as contact piece regions, a desired number of arcuate regions having desired lengths (angular ranges) in a circumferential direction in the annular zones B 1 , B 2  and B 3 . 
     In the upper contact piece  7 C 1  in  FIG. 3A , the annular zone B 1  includes one contact piece region C 1   a  of a predetermined angular range, and an empty region G 1   a  of a remaining angular range. The annular zone B 2  includes two contact piece regions C 1   b   1  and C 1   b   2  of a predetermined angular range, and empty regions G 1   b   1  and G 1   b   2  between the two adjacent contact piece regions. The annular zone B 3  includes one (360 degrees) empty region G 1   c . The contact piece regions C 1   a , C 1   b   1  and C 1   b   2  are regions with a metal surface of the contact piece  7 C 1  being exposed, and the empty regions G 1   a , G 1   b   1 , G 1   b   2  and G 1   c  are insulator surfaces of the disk part  72  flush with surfaces of the contact piece regions. 
     Meanwhile, in the lower contact piece  7 C 2  shown in  FIG. 3C , the annular zone B 1  includes four contact piece regions C 2   a   1 , C 2   a   2 , C 2   a   3  and C 2   a   4  of a predetermined angular range, and empty regions G 2   a   1 , G 2   a   2 , G 2   a   3  and G 2   a   4  between the four adjacent contact piece regions. The annular zone B 2  includes two contact piece regions C 2   b   1  and C 2   b   2  of a predetermined angular range, and empty regions G 2   b   1  and G 2   b   2  between the two adjacent contact piece regions. The annular zone B 3  includes one (360 degrees) contact piece region C 2   c . The contact piece regions C 2   a   1 , C 2   a   2 , C 2   a   3 , C 2   a   4 , C 2   b   1 , C 2   b   2  and C 2   c  are regions with a metal surface of the contact piece being exposed, and the empty regions G 2   a   1 , G 2   a   2 , G 2   a   3 , G 2   a   4 , G 2   b   1  and G 2   b   2  are insulator surfaces of the disk part  72  flush with surfaces of the contact piece regions. 
     In this embodiment, the upper contactor holder  80  and the lower contactor holder  60  have completely the same structure, and contactor holders formed as the same component can be used for an upper one and a lower one by turning upside down. Similarly, the cover  90  and the click spring support plate  50  have completely the same structure. The same structure can reduce production costs of the switch. 
       FIG. 5A  shows a lower surface of the lower contactor holder  60 , and a part of a lower surface of the rotor  70  seen above the lower contactor holder  60 . In an upper surface of the lower contactor holder  60 , a circular rotor housing recess  62  is formed, and a substantially rectangular window  61  is formed in a floor of the rotor housing recess  62 . On a side wall part of the rotor housing recess  62  adjacent to one side of the lower contactor holder  60 , an engaging protrusion  65  (also see  FIG. 1 ) protruding from the lower surface toward the upper contactor holder  80 , and an engaging recess  66  (also see  FIG. 1 ) adjacent to the engaging protrusion  65  with a side wall part being cut with the same width are formed. Positioning holes  64   a  are formed near a pair of the opposite corners of the lower contactor holder  60 , and securing holes  64   b  are formed near another pair of the opposite corners. Further, two positioning protrusions  63  are formed adjacent to one side of the lower contactor holder  60  from which the terminals  6 T 1 ,  6 T 2  and  6 T 3  are led out. 
     The lower contactor holder  60  is formed by insert molding together with three elastic contacts  6 C 1 ,  6 C 2  and  6 C 3  and terminals  6 T 1 ,  6 T 2  and  6 T 3  integrally extended therefrom and protruding outward from one side surface of the lower contactor holder  60 . The three elastic contacts  6 C 1 ,  6 C 2  and  6 C 3  extend inward from an edge of the window  61 , and tips thereof are located on the annular zones B 1 , B 2  and B 3  defined in the slide contact piece  7 C of the rotor  70 . Each of the elastic contacts  6 C 1 ,  6 C 2  and  6 C 3  has two branch arms, and is brought into two-point contact with each annular zone to increase stability (reliability) of contact and the life. 
       FIG. 5B  shows an upper surface of the upper contactor holder  80  and a part of an upper surface of the rotor  70  seen below the upper contactor holder  80 . As described above, the upper contactor holder  80  has completely the same structure as the lower contactor holder  60 . A circular rotor housing recess  82  is formed in a lower surface of the substantially rectangular upper contactor holder  80  like the housing part  22 , and a substantially rectangular window  81  is formed in a ceiling of the rotor housing recess  82 . On a side wall part of the rotor housing recess  82  adjacent to one side of the upper contactor holder  80 , an engaging protrusion  85  protruding from the lower surface toward the lower contactor holder  60 , and an engaging recess  86  adjacent to the engaging protrusion  85  and formed by cutting the side wall part with the same width. Positioning holes  84   a  are formed at a pair of the opposite corners of the lower contactor holder  80 , and securing holes  84   b  are formed at another pair of the opposite corners. Further, two positioning protrusions  83  are formed adjacent to one side of the upper contactor holder  80  from which the terminals  8 T 1 ,  8 T 2  and  8 T 3  are led out. 
     The upper contactor holder  80  is formed by insert molding together with three elastic contacts  8 C 1 ,  8 C 2  and  8 C 3  and terminals  8 T 1 ,  8 T 2  and  8 T 3  integrally extended therefrom and protruding outward from one side surface of the upper contactor holder  80 . The three elastic contacts  8 C 1 ,  8 C 2  and  8 C 3  extend inward from an edge of the window  81 , and tips thereof are located on the annular zones B 1 , B 2  and B 3  defined in the slide contact piece  7 C of the rotor  70 . Each of the elastic contacts  8 C 1 ,  8 C 2  and  8 C 3  has two branch arms, and is brought into two-point contact with each annular zone. 
     Returning to  FIG. 1 , the positioning protrusions  63  (see  FIG. 5A ) of the lower contactor holder  60  fit in the positioning holes  53   a  in the click spring support plate  50 , and the lower contactor holder  60  is positioned and secured on the click spring support plate  50 . Then, the driving part  13  of the rotating operation shaft  10  is inserted through the shaft hole  73  in the rotor  70  and a lower end of the rotation shaft  71  is inserted and engaged into the shaft hole  33  in the click disk  30  through the shaft hole  51  in the click spring support plate  50  so that substantially a lower half of the disk part  72  of the rotor  70  is placed in the rotor housing recess  62  in the lower contactor holder  60 . 
     The upper contactor holder  80  is placed on the rotor  70  and placed and secured on the lower contactor holder  60  so that a substantially upper half of the disk part  72  of the rotor  70  is housed in the rotor housing recess  82  in the upper contactor holder  80 . At this time, the engaging protrusion  85  and the engaging recess  86  (see  FIG. 5B ) of the upper contactor holder  80  fit the engaging recess  66  and the engaging protrusion  65  of the lower contactor holder  60 , respectively, and are mutually positioned. Further, an upper end of the rotation shaft  71  of the rotor  70  is inserted into the shaft hole  91  in the cover  90 , the cover  90  is placed on the upper contactor holder  80  so that the positioning protrusions  94  fit in the positioning holes  84   a  and the positioning protrusions  83  fit in the positioning holes  93   a . Thus, the elastic contacts  6 C 1 ,  6 C 2  and  6 C 3  of the lower contactor holder  60  are maintained in elastic contact with the lower surface of the disk part  72  of the rotor  70 , and the elastic contacts  8 C 1 ,  8 C 2  and  8 C 3  of the upper contactor holder  80  are maintained in elastic contact with the upper surface of the disk part  72  of the rotor  70 . 
     With the components thus assembled, two securing pins  8  are inserted through securing holes  93   b  in the cover  90 , the securing holes  84   b  in the upper contactor holder  80 , the securing holes  64   b  in the lower contactor holder  60 , the securing holes  53   b  in the click spring support plate  50 , and the securing holes  22   b  in the bearing  20 , and the tips of the pins  8  are riveted for integral securing. 
     The rotary switch is thus assembled, and thus the driving part  13  is inserted through the shaft hole  73  in the rotation shaft  71  of the rotor  70  inserted through the click disk  30  and the click spring support plate  50 , and supported in the shaft hole  91  in the cover  90 . A cross-section of the shaft hole  73  perpendicular to an axis thereof has a shape formed by cutting out arc portions along straight lines from a circle like the cross-section of the driving part  13 . Thus, when the rotor  70  is rotated by rotation of the rotating operation shaft  10 , the click disk  30  is also rotated. Thus, the protrusions  41  of the click spring  40  secured to the click spring support plate  50  engage radial irregularities on the rotating click disk  30  to cause click feeling in a rotational operation of the rotating operation shaft  10 , and slide contact/separation can be achieved between the upper and lower contact pieces  7 C 1  and  7 C 2  of the rotor  70  and the elastic contacts  8 C 1 ,  8 C 2 ,  8 C 3  and  6 C 1 ,  6 C 2 ,  6 C 3  of the upper and lower contactor holders. 
     As is understood from the above description, in a conventional case, if a circumferential length (angular width) of one fixed contact piece is determined within 360 degrees, circumferential lengths of the other fixed contact pieces must be determined within a remaining angle, which reduces flexibility in design. On the other hand, in the present invention, the contact piece regions within 360 degrees can be separately determined in radially different annular regions in upper and lower surfaces of the disk part of the rotor  70 , which advantageously increases flexibility in design. Specifically, this provides high flexibility in design of opening/closing angular ranges of a plurality of switches and relative timings as requested. 
     In the above embodiment, the case is described where the common annular zones B 1 , B 2  and B 3  are defined in the upper and lower contact pieces  7 C 1  and  7 C 2  of the rotor  70 . However, the number and width of annular zones may of course be separately defined for the upper and lower contact pieces  7 C 1  and  7 C 2 , and the number and arrangement of the elastic contacts of the upper contactor holder  80  and the lower contactor holder  60  may of course be determined according to the annular zones on each side. 
     Second Embodiment 
       FIG. 6  shows a second embodiment of a rotary switch according to the present invention. In the first embodiment described above, the lower contactor holder  60  is integrally formed with the elastic contacts  6 C 1 ,  6 C 2  and  6 C 3  by insert molding and then the elastic contacts  6 C 1 ,  6 C 2  and  6 C 3  are bent at a desired angle in the window  61 , and thus, the lower contactor holder  60  and the click spring support plate  50  are separately formed. However, when the lower contactor holder  60  can be insert molded with the elastic contacts  6 C 1 ,  6 C 2  and  6 C 3  being previously bent at a predetermined angle, as shown in  FIG. 6 , the lower contactor holder  60  and the click spring support plate  50  may be integrally formed as a lower holder (first holder)  60 ′. Similarly, as shown in  FIG. 6 , the upper holder  80  and the cover  90  in the first embodiment may be integrally formed as an upper holder (second holder)  80 ′. Other configurations are the same as in the first embodiment, and descriptions thereof will be omitted.