Abstract:
A push button switch has a box-shaped base, a first operating lever and a second operating lever, wherein each of the first operating lever and the second operating lever has a substantially U shape in a plan view, wherein the first operating lever and the second operating lever are arranged on the box-shaped base pivotally about middle parts of both arms as fulcra, and wherein the first operating lever and the second operating lever connect the tips of the both arms mutually pivotally and support the tips of the both arms in a vertically movable manner, an operating cover that has a planar shape covering the connected first and second operating levers and forms an operating hole at nearly the center thereof, and a plunger, wherein the plunger has a sectional shape capable of fitting into the operating hole of the operating cover.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    The present invention relates to a push button switch for use in elevators or the like, and in particular, to a self-illuminated push button switch. 
         [0003]    2. Related Art 
         [0004]    There is a push button switch having a parallelly operating link mechanism so as to allow an operating button to be stably operated without inclination as a self-illuminated push button switch (refer to Patent Literature 1). 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         Patent Literature 1: Japanese Patent Application Laid-open No. 2008-171794 
       
     
       SUMMARY 
       [0006]    However, as illustrated in FIG. 4 of Patent Literature 1, for example, the above push button switch arranges a leaf spring for operating a switch body arranged at nearly the center of a lever link mechanism immediately above the switch body. This requires light sources to be arranged near the switch body and the leaf spring and four light sources are required to be arranged to achieve desired luminous intensity, thereby being high in parts count and assembly man-hours. 
         [0007]    One or more embodiments of the present invention provides a push button switch that can be operated stably without inclining an operating button, has a low parts count, and has high illumination performance. 
         [0008]    A push button switch according to one or more embodiments of the present invention includes a box-shaped base; first and second operating levers that have a nearly U shape in a plan view, are arranged on the box-shaped base pivotally about middle parts of both arms, and connect the tips of the both arms mutually pivotally and support the tips of the both arms in a vertically movable manner; an operating cover that has a planar shape covering the connected first and second operating levers and forms an operating hole at nearly the center thereof; a plunger that has a sectional shape capable of fitting into the operating hole of the operating cover, is capable of pressing down the opening edge of the operating hole, and is formed of a transparent material; a switch body that is arranged in the middle area of the arms of the levers on the upper face of the box-shaped base and is driven by the plunger through the operating cover; and a light source positioned immediately below the plunger. 
         [0009]    One or more embodiments of the present invention achieves stable operation without inclination of the plunger by a parallelly operating link mechanism that operates by pressing down the pair of operating levers through the operating cover. 
         [0010]    The light source is positioned immediately below the plunger formed of the transparent material and has high illumination performance, thereby achieving a push button switch that can illuminate with a small number of light sources and is low in parts count and assembly man-hours. 
         [0011]    In one or more embodiments of the present invention, a cushioning material may be arranged between the switch body and the operating cover. 
         [0012]    One or more embodiments of the present invention achieves a push button switch that causes the cushioning material to absorb parts error and assembly errors and is free from rattling. 
         [0013]    In one or more embodiments of the present invention, the operating cover may be opaque. 
         [0014]    One or more embodiments of the present invention achieves a push button switch with reduced light leakage from the light source and further improved illumination performance. 
         [0015]    In one or more embodiments of the present invention, the light source mounted on the upper face of a printed board whose one end is inserted into an insertion hole formed in the base from below and that is assembled to the lower face of the base may be exposed out of a through hole formed in the base so as to be positioned immediately below the plunger. 
         [0016]    One or more embodiments of present invention may achieve a push button switch that can effectively utilize the thickness dimension of the bottom face of the base and is further thinner. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0017]      FIGS. 1A ,  1 B are perspective views illustrating a push button switch according to one or more embodiments of the present invention. 
           [0018]      FIGS. 2A ,  2 B,  2 C are a plan view, an elevational view of the push button switch illustrated in  FIG. 1 , and a C-C line plan sectional view of  FIG. 2B , respectively. 
           [0019]      FIG. 3  is an exploded perspective view of the perspective view illustrated in  FIG. 1A . 
           [0020]      FIG. 4  is an exploded perspective view of the perspective view illustrated in  FIG. 1B . 
           [0021]      FIGS. 5A ,  5 B,  5 C,  5 D are a plan view of a base illustrated in  FIG. 2A , a B-B line sectional view, a C-C line sectional view, and a D-D line sectional view of  FIG. 5A , respectively. 
           [0022]      FIGS. 6A ,  6 B,  6 C are an exploded perspective view, an exploded plan view of first and second operating levers illustrated in  FIG. 1A , and a C-C line sectional view of  FIG. 6B , respectively. 
           [0023]      FIGS. 7A ,  7 B,  7 C are a plan view of the push button switch illustrated in  FIG. 1A  before operation, a B-B line sectional view, and a C-C line sectional view of  FIG. 7A , respectively. 
           [0024]      FIGS. 8A ,  8 B,  8 C are a plan view of the push button switch illustrated in  FIG. 1A  after operation, a B-B line sectional view, and a C-C line sectional view of  FIG. 8A , respectively. 
           [0025]      FIGS. 9A ,  9 B are partial sectional elevational views illustrating the push button switch according to one or more embodiments of the present invention before and after operation, respectively. 
           [0026]      FIG. 10A  is a schematic diagram illustrating the operating principle,  FIG. 10B  is a schematic diagram illustrating the operating principle of the push button switch according to one or more embodiments of the present invention, and  FIG. 100  is a schematic diagram illustrating the operating principle of a push button switch according to a comparative example. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Embodiments of the present invention will be described with reference to the attached drawings of  FIG. 1  to  FIG. 10 . In embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the invention. 
         [0028]    As illustrated in  FIG. 3  and  FIG. 4 , the push button switch according to one or more embodiments of the present invention includes a nearly rectangular base  10  into which a printed board  20  is incorporated, first and second operating levers  30 ,  40 , an operating cover  50 , a plunger  60 , and an operating button  70 . 
         [0029]    As illustrated in  FIG. 5 , the base  10  protrudes a surrounding wall  11  on the upper face thereof and protrudes a cone-shaped circular protrusion  12   a  on the opening edge of the upper face of a through hole  12  formed at the central part of the upper face thereof. 
         [0030]    The base  10  forms positioning protrusions  13  around the circular protrusion  12   a  on the upper face thereof and protrudes positioning ribs  14   a ,  14   b  near the positioning protrusions  13 . The base  10  forms an insertion hole  15  between the positioning ribs  14   a ,  14   a  and forms a fitting step  15   a  so as to communicate with the insertion hole  15 . The base  10  protrudes insertion protrusions  17  for inserting coil springs  48  described below at one-side corners on the upper face thereof. 
         [0031]    The surrounding wall  11  forms two pairs of shaft receiving grooves  18   a ,  18   b  on the facing inner side walls thereof so that each pair of ones are on the same line and protrudes two pairs of retaining claws  16   a ,  16   b  on the residual facing inner side walls so that each pair of ones are arranged side by side. 
         [0032]    The base  10  forms a recess  19  ( FIG. 4 ) into which a printed board  20  described below is fitted so as to communicate with the insertion hole  15  on the lower face thereof. 
         [0033]    As illustrated in  FIG. 3 , the printed board  20  has a planar shape that can be fitted into the recess  19  formed on the bottom face of the base  10 . The printed board  20  mounts a pair of LEDs  21 ,  21  along the longitudinal direction at the central part of the upper face thereof, and mounts a tactile switch  22  at one end of the upper face thereof, and mounts a connector  23  at the other end of the upper face thereof. A rubber cushioning material  25  is fitted onto the upper face of the tactile switch  22  in order to absorb assembly errors and protect it from external impacts. 
         [0034]    As illustrated in  FIG. 2  and  FIG. 6 , the first and second operating levers  30 ,  40  form a frame shape along the inner circumferential face of the surrounding wall  11  of the base  10 . 
         [0035]    The first operating lever  30  is reinforced by connecting arms  32 ,  32  extended from both ends of a connecting part  31  with a connecting rod  33  and forms shaft receiving holes  34  at their tips. The first operating lever  30  forms pivoting shafts  35  on the outer side faces of the arms  32  on the same axis and forms retaining notches  36  at corners of the connecting part  31 . 
         [0036]    The second operating lever  40  is reinforced by connecting arms  42 ,  42  extended from both ends of a connecting part  41  with a connecting rod.  43  and protrudes connecting shafts  44  at the tips of the inner side faces of the arms  42  on the same axis. The second operating lever  40  forms pivoting shafts  45  on the outer side faces of the arms  42  on the same axis. The connecting part  41  forms retaining notches  46  at both ends of the outer face thereof and protrudes engagement shafts  47  on both end faces thereof on the same axis. 
         [0037]    The operating cover  50  has a planar shape that can be housed within the surrounding wall  11  of the base  10 , forms an operating hole  51  at the central part thereof, and forms locking protrusions  52  on the inner periphery of the operating hole  51  at a certain pitch. The operating cover  50  forms a support bent part  54  formed by bending downward between a pair of support tongue pieces  53 ,  53  cut out of the center of one side edge thereof. The operating cover  50  bends downward engagement tongue pieces  55  cut out of the corners positioned at the other side thereof. 
         [0038]    The plunger  60  has a disc shape that can be mounted on the opening edge of the operating hole  51  of the operating cover  50  and is formed of a transparent resin material that can diffuse the light of the LEDs  21 . The plunger  60  protrudes a circular rib  61  on the periphery of the upper face thereof and protrudes legs  62 ,  62  at facing positions on the opening edge of the lower face thereof. 
         [0039]    The plunger  60  forms locking recesses  63  to be locked to the locking protrusions  52  of the cover  50  to be integrated. 
         [0040]    The operating button  70  has a planar shape that can cover the plunger  60 , is formed of a transparent material in a shape having a nearly U-shaped cross section, and forms retaining claws  71  on the periphery at a certain pitch. 
         [0041]    Next, a method for assembling the above components will be described. One or more embodiments of the present invention is assembled so that the operating button  70  protrudes through an operating hole formed in a panel (not illustrated) in an operable manner. 
         [0042]    First, one end of the printed board  20  mounting the LEDs  21 , the tactile switch  22 , and the connector  23  is inserted into the insertion hole  15  of the base  10  from below, is fitted into the fitting step  15   a  formed on the upper face of the base  10 , and is then crimped within the recess  19  of the base  10  through crimping holes  24 . The tactile switch  22  is then covered with the cushioning material  25 . 
         [0043]    The return coil springs  48  are inserted into the insertion protrusions  17  of the base  10 . The connecting shafts  44  of the second operating lever  40  engage with the shaft receiving holes  34  of the first operating lever  30  to be pivotally assembled. The first and second operating levers  30 ,  40  are assembled to the upper face of the base  10 . In this situation, as illustrated in  FIG. 2 , the connecting part  31  of the first operating lever  30  is arranged between the retaining claws  16   a  and the positioning ribs  14   a , whereas the connecting rod  33  is arranged between the positioning ribs  14   a  and the positioning protrusions  13 . The pivoting shafts  35  of the first operating lever  30  engage with the shaft receiving grooves  18   a  formed on the inner circumferential face of the surrounding wall  11  of the base  10  to be pivotally supported. The tactile switch  22  is arranged between the shaft receiving holes  34  and the connecting part  31  of the first operating lever  30 . 
         [0044]    Similarly, the connecting part  41  of the second operating lever  40  is arranged between the retaining claws  16   b  and the positioning ribs  14   b , whereas the connecting rod  43  is arranged between the positioning ribs  14   b  and the positioning protrusions  13 . The pivoting shafts  45  of the second operating lever  40  engage with the shaft receiving grooves  18   b  formed on the inner circumferential face of the surrounding wall  11  of the base  10  to be pivotally supported. 
         [0045]    Thus, one or more embodiments of the present invention achieves a push button switch that is resistant to the occurrence of rattling and malfunction in the first and second operating levers  30 ,  40  even when vibrations are applied. 
         [0046]    The LEDs  21  mounted on the printed board  20  are exposed out of the through hole  12  of the base  10  with no shield thereabove, thereby causing the advantage of being capable of illuminating with a small number of LEDs  21  having high illumination performance. 
         [0047]    The connecting part  31  of the first operating lever  30  is held between the support tongue pieces  53  of the operating cover  50  with the plunger  60  assembled in advance and the support bent part  54 . The engagement tongue pieces  55  of the operating cover  50  engage with the engagement shafts  47  of the second operating lever  40 , thereby integrating the operating cover  50  into the first and second operating levers  30 ,  40 . Owing to this, the spring force of the coil springs  48  and the pushing-up force of the tactile switch  22  bias the connecting part  31  of the first operating lever  30  and the connecting part  41  of the second operating lever  40  upward, thereby positioning the tips of the arms  32 ,  42  of the first and second operating levers  30 ,  40  lowermost ( FIG. 7 ). 
         [0048]    The periphery on the lower face of the plunger  60  is mounted on the opening edge of the operating hole  51 , whereas as illustrated in  FIG. 2 , the legs  62  of the plunger  60  are positionally restricted by the positioning protrusions  13  of the base  10 . However, before operation, the legs  62  of the plunger  60  are suspended above the upper face of the base  10 . 
         [0049]    The operating button  70  is assembled to the plunger  60  and is positioned on the operating cover  50 . It is noted that, with one or more embodiments of the present invention, a panel (not illustrated) covers the push button switch and the operating button  70  protrudes through the operating hole of the panel in an operable manner. It is understood that the operating button may be a differently shaped operating button as needed. 
         [0050]    Next, the operation of the push button switch will be described with reference to  FIG. 7  to  FIG. 10 . 
         [0051]    As illustrated in  FIG. 7 , the operating cover  50  before operation is biased upward through the pushing-up force of the tactile switch  22  and the spring force of the coil springs  48 . Owing to this, the tips of the arms  32 ,  42  of the first and second operating levers  30 ,  40  are positioned lowermost. Because recesses  18   c  are formed at the corners on the upper face of the base  10 , the tips of the arms  32 ,  42  of the first and second operating levers  30 ,  40  are not in contact therewith. The retaining notches  36 ,  46  of the first and second operating levers  30 ,  40  engage with the retaining claws  16   a ,  16   b  of the base  10 , thereby preventing falling. 
         [0052]    When the operating button  70  is pressed down, the operating cover  50  is pressed down against the pushing-up force of the tactile switch  22  and the spring force of the coil springs  48 , thereby pivoting the first and second operating levers  30 ,  40  about the pivoting shafts  35  and the pivoting shafts  45  as fulcra, respectively. This causes the tips of the arms  32 ,  42  of the first and second operating levers  30 ,  40  to be lifted upward and causes the operating cover  50  to press down a push button part  22   a  of the tactile switch  22  through the cushioning material  25 . This causes the LEDs  21  to light up based on the switching operation of the tactile switch  22  or instructions from an external circuit when power is externally supplied to the components mounted on the printed board  20  through the connector  23 . 
         [0053]    When the pressing-down force on the operating button  70  is then released, the pushing-up force of the tactile switch  22  and the spring force of the coil springs  48  push up the connecting part  31  of the first operating lever  30  and the connecting part  41  of the second operating lever  40 , which return to their original positions through operation opposite to the above. 
         [0054]    With one or more embodiments of the present invention, the tactile switch  22  can be turned on and off without largely inclining the operating button  70  by the parallelly operating link mechanism including the operating levers  30 ,  40  even when an operation position on the operating button  70  is deviated from the center. 
         [0055]    The one or more embodiments of the present invention, for which partial sectional views before and after pressing down are illustrated in  FIGS. 9A ,  9 B, is described by schematically illustrating in  FIGS. 10A ,  10 B for the convenience of description. 
         [0056]    Specifically, the tactile switch  22  is arranged between the axis of the connecting part  31  of the first operating lever  30  and the axis of the shaft receiving holes  34  formed at the tips of the arms  32 . Owing to this, even when a maximum pushing-in amount D is small, the tactile switch  22  can be operated. 
         [0057]    When the tactile switch  22  is arranged outside the axis of the connecting part  31  of the first operating lever  30  as a comparative example illustrated in  FIG. 100 , the tactile switch  22  cannot be operated even when the maximum pushing-in amount D is the same as that of one or more embodiments of the present invention. In order for the comparative example to be operated, the maximum pushing-in amount D is required to be further increased. 
         [0058]    Thus, one or more embodiments of the present invention has the advantage of being capable of achieving a push button switch that can operate the tactile switch  22  with a relatively small amount of pushing-in amount and is thinner than the comparative example. 
         [0059]    A push button switch according to one or more embodiments of the present invention appropriately arranges the switch body between the connecting parts and the tips of the arms of the first and second operating levers so as to be operable through the operating cover and that the position of the switch body can be finely adjusted as needed. 
         [0060]    A push button switch according to one or more embodiments of the present invention can be used in other uses without being limited to elevators. 
         [0061]    While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims. 
       REFERENCE SIGNS LIST 
       [0000]    
       
         
           
               10  Base 
               11  Surrounding wall 
               12  Through hole 
               12   a  Circular protrusion 
               13  Positioning protrusion 
               14   a ,  14   b  Positioning rib 
               16   a ,  16   b  Retaining claw 
               17  Insertion protrusion 
               18   a ,  18   b  Shaft receiving groove 
               20  Printed board 
               21  LED 
               22  Tactile switch 
               23  Connector 
               24  Crimping hole 
               25  Cushioning material 
               30  First operating lever 
               31  Connecting part 
               32  Arm 
               33  Connecting rod 
               34  Shaft receiving hole 
               35  Pivoting shaft 
               36  Retaining notch 
               40  Second operating lever 
               41  Connecting part 
               42  Arm 
               43  Connecting rod 
               44  Connecting shaft 
               45  Pivoting shaft 
               46  Retaining notch 
               47  Engagement shaft 
               50  Operating cover 
               51  Operating hole 
               52  Locking protrusion 
               53  Support tongue piece 
               54  Support bent part 
               55  Engagement tongue piece 
               60  Plunger 
               62  Leg 
               63  Locking recess 
               70  Operating button