Patent Publication Number: US-11648572-B2

Title: Shower head

Description:
TECHNICAL FIELD 
     The present invention pertains to a shower head, in particular a shower head having a flow-path switching function. 
     BACKGROUND ART 
     A shower head having a flow-path switching function usually includes: a disc-shaped member, which is also called a water distribution board; and a driving mechanism for rotating the disc-shaped member for switching flow paths. Depending on various driving manners, various driving mechanisms have been developed, such as a driving mechanism using a button to be pushed, a driving mechanism using a rotatable surface cover, a driving mechanism using a swingable part, or the like. 
     In a shower head disclosed in JP-A-2016-140767, the surface area for receiving a pressure of water on an upper-surface side of a water distribution board (disc-shaped member) and the surface area for receiving a pressure of water on a lower-surface side of the water distribution board are made substantially equal to each other. Thus, a force exerted by the pressure of water on the upper-surface side of the water distribution board and a force exerted by the pressure of water on the lower-surface side of the water distribution board are substantially equal. As a result, an operation force required for rotating the water distribution board is relatively small, which leads to good operability. 
     Patent Document List 
     JP-A-2016-140767 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the above type of shower head, the disc-shaped member is usually slidably rotated to switch the flow paths. In order to enhance the slidability, grease is generally applied. However, the operation force for switching the flow paths varies depending on the amount of the applied grease. In addition, the applied grease may gradually leak out, so that the operation force for switching the flow paths may be increased after a long-term use. 
     The present invention has been made based on the above findings. The object of the present invention is to provide a shower head in which a remarkable and stable reduction of an operation force for switching flow paths is achieved. 
     Solution to Problem 
     The present invention is a shower head having a flow path configured to guide water to a plurality of spout holes, the shower head including: a main valve body movably supported in the flow path; a back pressure chamber adjacent to the main valve body on an upstream side of the flow path, configured to contain water supplied from an upstream side of the flow path and to generate a biasing force in a valve-closing direction for closing the main valve body by the supplied water; a pilot hole communicating a downstream side of the flow path with the back pressure chamber; a pilot valve configured to selectively control an opened/closed state of the pilot hole; and an operation part to be operated by a user, configured to cause the pilot valve to switch the opened/closed state of the pilot hole when operated by the user. 
     According to the above feature, since the main valve body is opened and closed by switching the opened/closed state of the pilot hole by means of the pilot valve, a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
     Alternatively, the present invention is a shower head having a flow path configured to guide water to a plurality of spout holes, the shower head including: a plurality of main valve bodies movably supported in the flow path; a plurality of back pressure chambers, each of which is adjacent to each of the plurality of main valve bodies on an upstream side of the flow path and is configured to contain water supplied from an upstream side of the flow path and to generate a biasing force in a valve-closing direction for closing the corresponding main valve body by the supplied water; a plurality of pilot holes communicating a downstream side of the flow path with the plurality of back pressure chambers; a pilot valve configured to selectively control opened/closed states of the plurality of pilot holes; and an operation part to be operated by a user, configured to cause the pilot valve to switch the opened/closed states of the plurality of pilot holes when operated by the user. 
     According to the above feature, since the plurality of main valve bodies are respectively opened and closed by switching the opened/closed states of the plurality of pilot holes by means of the pilot valve, a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
     In this case, it is preferable that the pilot valve has a plurality of communication holes, and that each of the plurality of communication holes is configured to open a corresponding pilot hole of a corresponding main valve body when selectively communicating with a corresponding back-pressure-chamber outlet hole provided on a corresponding back pressure chamber of the corresponding main valve body. 
     According to the above feature, it is possible to design a control for opening and closing the plurality of pilot holes for the plurality of main valve bodies with a higher degree of freedom. Thus, it is possible to achieve various switching controls. 
     Alternatively, the present invention is a shower head for which a plurality of spout modes can be switched, the shower head including: a storage chamber configured to store water supplied from a water supply source; a secondary-side flow-path member provided on a spout-surface side with respect to the storage chamber, the secondary-side flow-path member having a plurality of flow paths, each of which corresponds to each of the plurality of spout modes; and a plurality of diaphragm valves, each of which is configured to control a communicated/blocked state between each of the plurality of flow paths and the storage chamber. 
     According to the above feature, since the communicated/blocked state between each of the plurality of flow paths and the storage chamber is controlled by each of the plurality of diaphragm valves, a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
     When the plurality of diaphragm valves are two diaphragm valves, it is preferable that a pilot hole for communicating a back pressure chamber of each of the two diaphragm valves with a space outside the storage chamber is collectively located at a middle region between the two diaphragm valves so that the pilot hole is opened and closed by a common pilot valve. 
     According to this arrangement, the shower head may be designed to be compact. In addition, a moving range (moving distance) of the pilot valve may be designed to be smaller, which can lead to a further reduction of the operating force. 
     Substantially similarly, when the plurality of diaphragm valves are three or more diaphragm valves which are annularly arranged, it is preferable that a pilot hole for communicating a back pressure chamber of each of the three or more diaphragm valves with a space outside the storage chamber is collectively located at a central region of the three or more diaphragm valves so that the pilot hole is opened and closed by a common pilot valve. 
     According to this arrangement as well, the shower head may be designed to be compact. In addition, a moving range (moving distance) of the pilot valve may be designed to be smaller, which can lead to a further reduction of the operating force. 
     Furthermore, it is preferable that the common pilot valve is a disc-shaped member supported in a rotatable manner around an axis thereof and having teeth on an outer circumference thereof. 
     According to this feature, it is possible to easily drive the disc-shaped member in rotation by using the teeth on the outer circumference of the disc-shaped member. 
     In addition, in this case, it is further preferable that the disc-shaped member is made of resin. 
     According to this feature, it is possible to easily achieve high smoothness, which can inhibit sliding resistance (sliding friction). In addition, it is unnecessary to separately provide a seal part. 
     In addition, it is preferable that the disc-shaped member has a plurality of communication holes, and that each of the plurality of communication holes is configured to open a corresponding pilot hole of a corresponding diaphragm valve when selectively communicating with a corresponding back-pressure-chamber outlet hole provided on a corresponding back pressure chamber of the corresponding diaphragm valve, in response to a rotational position of the disc-shaped member. 
     According to this arrangement, the shower head may be designed to be more compact. In addition, a rotation angle (moving distance) of the disc-shaped member (pilot valve) may be designed to be smaller, which can lead to a further reduction of the operating force. 
     In addition, it is preferable that a disc-pushing member is interposed between the corresponding back-pressure-chamber outlet hole and the disc-shaped member, and that the disc-pushing member has an outlet communication hole that can communicate with the corresponding back-pressure-chamber outlet hole provided on the corresponding back pressure chamber of the corresponding diaphragm valve, and that the disc-pushing member is configured to push the disc-shaped member away from the corresponding back-pressure-chamber outlet hole by means of a biasing part. 
     According to this arrangement, it is unnecessary to provide a seal part between the disc-shaped member and a member located away from the back-pressure-chamber outlet hole with respect to the disc-shaped member. 
     In this case, it is further preferable that the outlet communication hole is formed by a tubular part, that the tubular part is inserted into the corresponding back-pressure-chamber outlet hole, that there remains a gap between the tubular part and the corresponding back-pressure-chamber outlet hole, and that the gap is configured to function as a corresponding back-pressure-chamber inlet hole. 
     It is easy to form the gap with high precision. Thus, it is possible to effectively inhibit variation in performance among the plurality of back-pressure-chamber inlet holes for the plurality of diaphragm valves. 
     In addition, it is preferable that the shower head according to one of the above features of the present invention further includes: an operation part configured to receive an operation force from a user; a shaft part configured to reciprocate in an axial direction thereof every time the operation part receives the operation force; and a claw member attached to a distal end portion of the shaft part and having a claw configured to engage with the teeth of the disc-shaped member; wherein the disc-shaped member is rotated when the claw draws the teeth while the shaft part reciprocates. 
     Since a force for driving the disc-shaped member in rotation is applied in a direction in which the claw draws the teeth, it is possible to prevent buckling deformation of the shaft part. Thus, rigidity required for the shaft part can be reduced. As a result, it is possible to make the shaft part of not only a rigid material but also a plastic material or an elastic material. 
     In this case, it is further preferable that a proximal end portion of the shaft part is connected to the operation part, that a coil spring is arranged around the shaft part, that a proximal end of the coil spring is fixed to a shower head housing, that a distal end of the coil spring is fixed to the claw member, that a stopper for the claw member is attached to a distal end portion of the shaft part, and that the claw member is movable relative to the shaft part by deformation of the coil spring. 
     According to this feature, after the claw member has drawn one tooth, when the claw member is returned to an original position thereof to engage with the next tooth, it is possible to effectively avoid resistance (interference) from the disc-shaped member. 
     In addition, for example, the plurality of diaphragm valves may be integrally connected as one diaphragm member. In this case, it is preferable that the diaphragm member has a seal part at a periphery thereof. Alternatively, the plurality of diaphragm valves may be formed as separate independent parts, respectively. 
     In order to stabilize a movement for opening and closing each of the plurality of diaphragm valves, it is preferable that each of the plurality of diaphragm valves is biased in a valve-closing direction by means of an elastic member. 
     Advantageous Effects of Invention 
     According to one feature of the present invention, since the main valve body is opened and closed by switching the opened/closed state of the pilot hole by means of the pilot valve, a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
     According to another feature of the present invention, since the plurality of main valve bodies are respectively opened and closed by switching the opened/closed states of the plurality of pilot holes by means of the pilot valve, a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
     According to further another feature of the present invention, since the communicated/blocked state between each of the plurality of flow paths and the storage chamber is controlled by each of the plurality of diaphragm valves, a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a partially sectional perspective view of a shower head according to a first embodiment of the present invention; 
         FIG.  2    is a partially longitudinal section view of the shower head shown in  FIG.  1   ; 
         FIG.  3    is an exploded perspective view of the shower head shown in  FIG.  1   ; 
         FIG.  4    is a schematic view for explaining an opened/closed state of a pilot hole; 
         FIG.  5    is a schematic view for explaining a disc-pushing member; 
         FIG.  6    is a schematic view for explaining a state wherein a disc-shaped member has started to be rotated; 
         FIG.  7    is a schematic view for explaining a state wherein the disc-shaped member is being rotated; 
         FIG.  8    is a schematic view for explaining a state wherein the disc-shaped member has finished to be rotated; 
         FIG.  9    is a plan view of a shower head according to a second embodiment of the present invention; 
         FIG.  10    is a section view taken along line X-X of the shower head shown in  FIG.  9   ; 
         FIG.  11    is an exploded perspective view of the shower head shown in  FIG.  9   ; 
         FIG.  12    is a schematic view for explaining an opened/closed state of a pilot hole; 
         FIG.  13    is a schematic view for explaining a disc-pushing member; 
         FIG.  14    is a schematic view for explaining a state wherein a disc-shaped member has started to be rotated; 
         FIG.  15    is a schematic view, corresponding to  FIG.  13   , for explaining a variation of the second embodiment; 
         FIG.  16    is a partially sectional perspective view of a shower head according to a third embodiment of the present invention; 
         FIG.  17    is a partially longitudinal section view of the shower head shown in 
         FIG.  16   ; 
         FIG.  18    is an exploded perspective view of the shower head shown in  FIG.  16   ; 
         FIG.  19    is a perspective view of a shower head according to a fourth embodiment of the present invention; 
         FIG.  20    is a front view of the shower head shown in  FIG.  19   ; 
         FIG.  21    is a longitudinal section view taken along line XXI-XXI of the shower head shown in  FIG.  20   ; 
         FIG.  22    is a transversal section view taken along line XXII-XXII of the shower head shown in  FIG.  21   ; 
         FIG.  23    is an exploded perspective view of the shower head shown in  FIG.  19   ; 
         FIG.  24    is a schematic view for explaining an opened/closed state of a pilot hole; 
         FIG.  25    is a schematic view for explaining a state wherein a first disc-shaped member has started to be rotated; 
         FIG.  26    is a schematic view for explaining a state wherein the first disc-shaped member is being rotated; 
         FIG.  27    is a schematic view for explaining a state wherein the first disc-shaped member has finished to be rotated; 
         FIG.  28    is a schematic view for explaining a state wherein a second disc-shaped member has started to be rotated; 
         FIG.  29    is a schematic view for explaining a state wherein the second disc-shaped member is being rotated; and 
         FIG.  30    is a schematic view for explaining a state wherein the second disc-shaped member has finished to be rotated; 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Structure of First Embodiment 
     Hereinafter, a shower head according to a first embodiment of the present invention will be described with reference to the attached drawings. The shower head  1  of the first embodiment is a shower head for which a plurality of spout modes can be switched (water can be discharged in each of the plurality of spout modes). 
       FIG.  1    is a partially sectional perspective view of the shower head  1  of the first embodiment.  FIG.  2    is a partially longitudinal section view of the shower head  1  of the first embodiment.  FIG.  3    is an exploded perspective view of the shower head  1  of the first embodiment. 
     As shown in  FIGS.  1  to  3   , the shower head  1  of the first embodiment includes a storage chamber  5  (which is also called cavity) configured to store water supplied from a water supply source (not shown) through water supply members  2 ,  3 . 
     A secondary-side flow-path member  4  is provided on a spout-surface side of the shower head  1  with respect to the storage chamber  5 . The secondary-side flow-path member  4  consists of four stacked substantially discoid element parts  40 ,  47 ,  48 ,  49 . The secondary-side flow-path member  4  has three flow paths (an example of a plurality of flow paths), each of which corresponds to each of three spout modes (an example of the plurality of spout modes). 
     Three valve seats  41  to  43  protruded on a side of the storage chamber  5  are formed on the element part  40  facing to the storage chamber  5 . A communication hole that communicates with a corresponding flow path among the three flow paths is provided at a center of each of the valve seats  41  to  43  (see  FIG.  4   , too). The three valve seats  41  to  43  (and their corresponding communication holes) are annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. 
     Three diaphragm valves  21  to  23 , which correspond to the three valve seats  41  to  43 , respectively, are annularly arranged. The three diaphragm valves  21  to  23  are integrally formed as one diaphragm member  20 . However, the respective diaphragm valves  21  to  23  are movable independently of each other. 
     A seal ring portion  24  is formed at a periphery of the diaphragm member  20 . The seal ring portion  24  is sandwiched between an upper edge portion  40   a  of the element part  40  and a cover member  8  in a watertight manner. A central area of the diaphragm member  20  is supported on an upper surface of the element part  40  via a spacing member  38 . 
     Coil springs  51  to  53  (an example of an elastic member) are provided between the respective diaphragm valves  21  to  23  and a lower surface of the cover member  8 , so that each of the diaphragm valves  21  to  23  is biased in a valve-closing direction by means of the corresponding coil spring  51  to  53 . 
     The three diaphragm valves  21  to  23  of the present embodiment are annularly arranged, and a pilot hole (a part of which is a back-pressure-chamber outlet hole  21   c  to  23   c  formed on a lower-surface side of the cover member  8 ) for communicating a back pressure chamber  21   b  to  23   b  of each of the three diaphragm valves  21  to  23  with a space below the element part  40 , which is a space outside the storage chamber  5 , is collectively located at a central region of the three diaphragm valves  21  to  23 , so that the pilot hole is opened and closed by a disc-shaped member  10 , which serves as a common pilot valve. (When the number of the plurality of diaphragm valves is two, a pilot hole for communicating a back pressure chamber of each of the two diaphragm valves with the space below the element part  40  may be collectively located at a middle region of the two diaphragm valves.) 
     The disc-shaped member  10  is made of resin. The disc-shaped member  10  is supported in a rotatable manner around an axis thereof, and has twelve teeth  10   t  on an outer circumference thereof (see  FIGS.  6  to  8   , too). 
       FIG.  4    is a schematic view for explaining an opened/closed state of a pilot hole. The disc-shaped member  10  has four communication holes  10   h  (an example of the plurality of communication holes). As shown in  FIG.  4    schematically, each of the four communication holes  10   h  is configured to open a corresponding pilot hole of a corresponding diaphragm valve  21  to  23  when selectively communicating with a corresponding back-pressure-chamber outlet hole  21   c  to  23   c  provided on a corresponding back pressure chamber  21   b  to  23   b  of the corresponding diaphragm valve  21  to  23 , in response to a rotational position of the disc-shaped member  10 . More specifically, when each of the four communication holes  10   h  selectively communicates with the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  and a corresponding outlet hole  44  to  46  in the element part  40  provided correspondingly to the corresponding back-pressure-chamber outlet hole  21   c  to  23   c , the corresponding pilot hole of the corresponding diaphragm valve  21  to  23  is opened. The four communication holes  10   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 90 degrees. The back-pressure-chamber outlet holes  21   c  to  23   c  and the outlet holes  44  to  46  are also annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. 
       FIG.  5    is a schematic view for explaining a disc-pushing member  30 . As shown in  FIG.  5    schematically, the disc-pushing member  30  is interposed between the back-pressure-chamber outlet holes  21   c  to  23   c  and the disc-shaped member  10 . The disc-pushing member  30  is configured to push the disc-shaped member  10  away from the back-pressure-chamber outlet holes  21   c  to  23   c  (toward the element part  40 ) by means of a coil spring  35  as an example of a biasing part. 
     The disc-pushing member  30  is provided with three outlet communication holes  31   c  to  33   c , each of which can communicate with the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  provided on the corresponding back pressure chamber  21   b  to  23   b  of the corresponding diaphragm valve  21  to  23 . In the present embodiment, each of the outlet communication holes  31   c  to  33   c  is formed by a tubular part  31  to  33 . Each of the tubular parts  31  to  33  is inserted into the corresponding back-pressure-chamber outlet hole  21   c  to  23   c.    
     There remains a gap between each of the tubular parts  31  to  33  and the corresponding back-pressure-chamber outlet hole  21   c  to  23   c , and the gap is configured to function as a corresponding back-pressure-chamber inlet hole. (However, at least at the time of filing the present application, the scope of the present invention does not exclude a manner wherein each of back-pressure-chamber inlet holes  21   d  to  23   d  is provided through a portion of the corresponding diaphragm valve  21  to  23 , as shown in  FIG.  4   ). 
     With reference to  FIG.  2    again, a push button  11  is provided on a lower portion of a shower head housing  7  as an operation part configured to receive an operation force from a user. (Any other type of button or slide switch may be provided in place of the push button  11 .) 
     Every time the push button  11  receives an operation force (a pushing force) from a user (every time the user gives an operation force (a pushing force) to the push button  11 ), the push button  11  pivots around a pivot shaft  11   s . Then, in coordination with the pivot movement, by means of abutment and slide between an abutment slide inclined portion  11   a  of the push button  11  and an abutment slide ring part  12   a  provided at a proximal end portion of a shaft part  12 , the shaft part  12  is configured to reciprocate in an axial direction thereof. 
     A distal end portion of the shaft part  12  is exposed to the water in the storage chamber  5  (see  FIGS.  6  to  8   , too). Thus, the shaft part  12  is made of a metal bar which is difficult to rust, such as a stainless-steel bar. In the present embodiment, the shaft part  12  slidably pierces through the element part  40  integrally fixed to the shower head housing  7 . A seal ring part  12   s  is provided for maintaining watertight performance. The shaft part  12  may be made of not only a rigid material but also a plastic material such as string or an elastic material such as rubber. 
       FIG.  6    is a schematic view for explaining a state wherein the disc-shaped member  10  has started to be rotated,  FIG.  7    is a schematic view for explaining a state wherein the disc-shaped member  10  is being rotated, and  FIG.  8    is a schematic view for explaining a state wherein the disc-shaped member  10  has finished to be rotated. 
     As shown in  FIGS.  6  to  8   , a coil spring  14  is arranged around a distal end portion of the shaft part  12  located in the storage chamber  5 . A proximal end of the coil spring  14  is fixed to the element part  40 , and thus fixed to the shower head housing  7  (to the pivot shaft  11   s  of the push button  11 ). 
     A claw member  15  is fixed to a distal end of the coil spring  14 . A stopper  13  for the claw member  15  is attached to the distal end portion of the shaft part  12 . The distal end of the coil spring  14  and the claw member  15  are movable in an axial direction by deformation of the coil spring  14  in the axial direction in a region on the side of the proximal end portion of the shaft part  12  with respect to the stopper  13 . 
     Furthermore, the distal end of the coil spring  14  and the claw member  15  are also movable in an inclined direction, which is inclined with respect to the axial direction of the coil spring  14 , by deformation of the coil spring  14  in the inclined direction. 
     A claw  15   t  is provided on a lateral surface of the claw member  15  on the side of the disc-shaped member  10 . The claw  15   t  is configured to engage with the teeth  10   t  of the disc-shaped member  10 . The disc-shaped member  10  is rotated when the claw  15   t  draws one of the teeth  10   t  while the shaft part  12  reciprocates (from the state shown in  FIG.  6   , through the stage shown in  FIG.  7   , to the state sown in  FIG.  8   ). 
     In addition, a stopper claw  16  configured to prevent the disc-shaped member  10  (teeth  10   t ) from reversely rotating is held by a stopper-claw fixing part  17  provided on the element part  40 . 
     Operation of First Embodiment 
     Next, an operation of the shower head  1  according to the first embodiment is explained. 
     With reference to  FIG.  2   , when a user pushes the push button  11 , the pushing force (operating force) causes the abutment slide inclined portion  11   a  of the push button  11  to pivot around the pivot shaft  11   s , so that the shaft part  12  moves in a direction toward the proximal end portion thereof (the right side in  FIG.  2   ) via the abutment slide ring part  12   a.    
     The state shown in  FIG.  6    corresponds to a state before the user pushes the push button  11 . From this state, the shaft part  12  starts to move. When the claw  15   t  of the claw member  15  draws one of the teeth  10   t  of the disc-shaped member  10 , the disc-shaped member  10  is rotated, as shown in  FIG.  7   . The state shown in  FIG.  8    corresponds to a state wherein the push button  11  has been pushed to a deepest position thereof and thus the shaft part  12  has moved to a most proximal-end-side position thereof (rightmost position in  FIG.  2   ). In the state shown in  FIG.  8   , the stopper claw  16  stops a tooth  10   t  next to that in  FIG.  6   . Accordingly, the disc-shaped member  10  is rotated by 30 degrees every time the user pushes the push button  11 . 
     In the state shown in  FIG.  8   , the coil spring  14  is compressed between the claw member  15  (and the stopper  13  at the distal end portion of the shaft part  12 ) and the element part  40 . From this state, when the pushing force against the push button  11  is released, the shaft part  12  and the push button  11  are returned back to their original positions (the state shown in  FIG.  6   ) by a resilience force of the coil spring  14 . During this step, the claw  15   t  does not engage with any tooth  10   t , and the disc-shaped member  10  is not reversely rotated in combination with the existence of the claw stopper  16 . In addition, during the above step, the claw member  15  is movable in the inclined direction, which is inclined with respect to the axial direction of the coil spring  14 , by the deformation of the coil spring  14  in the inclined direction. Thus, it is possible to effectively avoid resistance (interference) from the disc-shaped member  10 . In addition, when the claw member  15  is returned back to an original position thereof (the state shown in  FIG.  6   ), the claw member  15  (claw  15   t ) engages with the tooth  10   t  next to the previously drawn one, by the resilience force of the coil spring  14 . 
     As described above, the four communication holes  10   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 90 degrees, and the back-pressure-chamber outlet holes  21   c  to  23   c  and the outlet holes  44  to  46  are annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. Thus, when the disc-shaped member  10  is rotated by 30 degrees, it is possible to sequentially switch the following three spout modes: 
     (i) a first spout mode wherein the back-pressure-chamber outlet holes  21   c  and the outlet hole  44  communicate with each other while the back-pressure-chamber outlet holes  22   c ,  23   c  and the outlet holes  45 ,  46  do not communicate with each other; 
     (ii) a second spout mode wherein the back-pressure-chamber outlet holes  22   c  and the outlet hole  45  communicate with each other while the back-pressure-chamber outlet holes  21   c ,  23   c  and the outlet holes  44 ,  46  do not communicate with each other; and
         (iii) a third spout mode wherein the back-pressure-chamber outlet holes  23   c  and the outlet hole  46  communicate with each other while the back-pressure-chamber outlet holes  21   c ,  22   c  and the outlet holes  44 ,  45  do not communicate with each other.       

     The state shown in the right side half of  FIG.  4    or  FIG.  5    is an example of a state wherein a back-pressure-chamber outlet hole and the corresponding outlet hole do not communicate with each other, i.e., the corresponding pilot hole of the corresponding diaphragm valve is not opened. In the state shown in the right side half of  FIG.  4    or  FIG.  5   , the back-pressure-chamber outlet holes  22   c ,  23   c  and the corresponding outlet holes  45 ,  46  are blocked by the disc-shaped member  10 . On the other hand, through the back-pressure-chamber inlet holes  22   d ,  23   d  (in the case shown in  FIG.  4   ) or through the gaps between the tubular parts  32 ,  33  and the corresponding back-pressure-chamber outlet holes  22   c ,  23   c  (in the case shown in  FIG.  5   ), the water pressure in the storage chamber  5  and the water pressures in the back pressure chambers  23   b ,  23   c  are made equal to each other. Thus, each of the diaphragm valves  22 ,  23  is closed by a biasing force of the corresponding coil spring  52 ,  53  (not shown in  FIGS.  4  and  5   ). 
     The state shown in the left side half of  FIG.  4    or  FIG.  5    is an example of a state wherein a back-pressure-chamber outlet hole and the corresponding outlet hole communicate with each other, i.e., the corresponding pilot hole of the corresponding diaphragm valve is opened. In the state shown in the left side half of  FIG.  4    or  FIG.  5   , the back-pressure-chamber outlet hole  21   c  and the corresponding outlet hole  44  communicate with each other through the communication hole  10   h  of the disc-shaped member  10 . In this state, the water in the back pressure chamber  21   b  flows out through the back-pressure-chamber outlet hole  21   c  and the corresponding outlet hole  44 , so that the water pressure in the storage chamber  5  becomes greater than the water pressure in the back pressure chamber  21   b . Thus, the diaphragm valve  21  is opened in spite of the biasing force of the corresponding coil spring  51  (not shown in  FIGS.  4  and  5   ). 
     Effects of First Embodiment 
     As described above, according to the shower head  1  of the first embodiment, since the communicated/blocked state between each of the three flow paths and the storage chamber  5  is controlled by each of the three diaphragm valves  21  to  23 , a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
     In particular, according to the shower head  1  of the first embodiment, the pilot hole for communicating the back pressure chamber  21   b  to  23   b  of each of the annularly-arranged three diaphragm valves  21  to  23  with the space outside the storage chamber  5  is collectively located at the central region of the three diaphragm valves  21  to  23  so that the pilot hole is opened and closed by the common disc-shaped member  10  (pilot valve). Thus, the shower head  1  is made to be compact. In addition, a moving range (moving distance) of the disc-shaped member  10  (pilot valve) is sufficiently small, which contributes to a further reduction of the operating force. 
     In addition, according to the shower head  1  of the first embodiment, the disc-shaped member  10  is supported in a rotatable manner around the axis thereof and has the teeth  10   t  on the outer circumference thereof. Thus, it is possible to easily drive the disc-shaped member  10  in rotation by using the teeth  10   t.    
     In addition, according to the shower head  1  of the first embodiment, the disc-shaped member  10  is made of resin. Thus, it is possible to easily achieve high smoothness, which can inhibit sliding resistance (sliding friction). In addition, it is unnecessary to separately provide a seal part. 
     In addition, according to the shower head  1  of the first embodiment, the disc-shaped member  10  has the four communication holes  10   h , and each of the four communication holes  10   h  is configured to open the corresponding pilot hole of the corresponding diaphragm valve  21  to  23  when selectively communicating with the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  provided on the corresponding back pressure chamber  21   b  to  23   b  of the corresponding diaphragm valve  21  to  23 , in response to a rotational position of the disc-shaped member  10 . Thus, the shower head  1  is made to be more compact. In addition, a rotation angle (moving distance) of the disc-shaped member  10  (pilot valve) is sufficiently small (no more than 30 degrees), which contributes to a further reduction of the operating force. 
     In addition, according to the shower head  1  of the first embodiment, the disc-pushing member  30  is interposed between the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  and the disc-shaped member  10 , the disc-pushing member  30  has the outlet communication holes  31   c  to  33   c  each of which can communicate with the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  provided on the corresponding back pressure chamber  21   b  to  23   b  of the corresponding diaphragm valve  21  to  23 , and the disc-pushing member  30  is configured to push the disc-shaped member  10  away from the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  by means of the coil spring  35 . Thus, it is unnecessary to provide a seal part between the disc-shaped member  10  and the element part  40  (a member located away from the back-pressure-chamber outlet holes  21   c  to  23   c  with respect to the disc-shaped member  10 ). 
     In particular, according to the shower head  1  of the first embodiment, each of the outlet communication holes  31   c  to  33   c  is formed by the corresponding tubular part  31  to  33 , each of the tubular parts  31  to  33  is inserted into the corresponding back-pressure-chamber outlet hole  21   c  to  23   c , the gap between each of the tubular parts  31  to  33  and the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  is configured to function as a corresponding back-pressure-chamber inlet hole. It is easy to form the gap with high precision, and thus it is possible to effectively inhibit variation in performance among the three back-pressure-chamber inlet holes (the three gaps) for the three diaphragm valves  21  to  23 . 
     In addition, according to the shower head  1  of the first embodiment, by using a driving mechanism including: the push button  11  configured to receive an operation force from a user; the shaft part  12  configured to reciprocate in the axial direction thereof every time the push button  11  receives the operation force; and the claw member  15  attached to the distal end portion of the shaft part  12  and having the claw  15   t  configured to engage with the teeth  10   t  of the disc-shaped member  10 , the disc-shaped member  10  is rotated when the claw  15   t  draws one of the teeth  10   t  while the shaft part  12  reciprocates. Since the force for driving the disc-shaped member  10  in rotation is applied in a direction in which the claw  15   t  draws one of the teeth  10   t , it is possible to prevent (avoid) buckling deformation of the shaft part  12 . Thus, rigidity required for the shaft part  12  can be reduced. As a result, it is possible to make the shaft part  12  of not only a rigid material but also a plastic material such as string or an elastic material such as rubber. 
     In particular, according to the shower head  1  of the first embodiment, the proximal end portion of the shaft part  12  is operably connected to the push button part  11 , the coil spring  14  is arranged around the distal end portion of the shaft part  12 , the proximal end of the coil spring  14  is fixed to the element part  40 , the distal end of the coil spring  14  is fixed to the claw member  15 , and the stopper  13  for the claw member  15  is attached to the distal end portion of the shaft part  12 . Thus, the claw member  15  is movable relative to the shaft part  12  by deformation of the coil spring  14  (both in the axial direction and in the inclined direction). Thus, after the claw member  15  has drawn one tooth  10   t , when the claw member  15  is returned to the original position thereof (the state shown in  FIG.  6   ) to engage with the next tooth  10   t , it is possible to effectively avoid resistance (interference) from the disc-shaped member  10 . 
     In addition, according to the shower head  1  of the first embodiment, the three diaphragm valves  21  to  23  are integrally formed as the one diaphragm member  20 , and the seal ring portion  24  is provided at the periphery of the diaphragm member  20 . Thus, it is unnecessary to separately provide a seal ring part. 
     In addition, according to the shower head  1  of the first embodiment, each of the three diaphragm valves  21  to  23  is biased in a valve-closing direction by means of the corresponding coil spring  51  to  53 . Thus, the movement for opening and closing each of the three diaphragm valves  21  to  23  is stabilized. 
     Structure of Second Embodiment 
     Hereinafter, a shower head according to a second embodiment of the present invention will be described with reference to the attached drawings. The shower head  101  of the second embodiment is also a shower head for which a plurality of spout modes can be switched (water can be discharged in each of the plurality of spout modes). 
       FIG.  9    is a plan view of the shower head  101  according to the second embodiment of the present invention,  FIG.  10    is a section view taken along line X-X of the shower head  101  shown in  FIG.  9   , and  FIG.  11    is an exploded perspective view of the shower head  101  shown in  FIG.  9   . 
     As shown in  FIGS.  9  to  11   , the shower head  101  of the second embodiment also includes a storage chamber  105  (which is also called cavity) configured to store water supplied from a water supply source (not shown) through water supply members  102 ,  103 . 
     A secondary-side flow-path member  104  is provided on a spout-surface side of the shower head  101  with respect to the storage chamber  105 . The secondary-side flow-path member  104  consists of four stacked substantially discoid element parts  140 ,  147 ,  148 ,  149 , three central spout parts  161 ,  162 ,  163 , and a seal part  165 . The secondary-side flow-path member  104  has three flow paths (an example of a plurality of flow paths), each of which corresponds to each of three spout modes (an example of the plurality of spout modes). 
     Three valve seats  141  to  143  protruded on a side of the storage chamber  105  are formed on the element part  140  facing to the storage chamber  105 . A communication hole that communicates with a corresponding flow path among the three flow paths is provided at a center of each of the valve seats  141  to  143 . The three valve seats  141  to  143  (and their corresponding communication holes) are annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. 
     Three diaphragm valves  121  to  123 , which correspond to the three valve seats  141  to  143 , respectively, are annularly arranged. The three diaphragm valves  121  to  123  are separate independent members, which is different from the first embodiment. 
     A seal ring part  124  is arranged to surround the three diaphragm valves  121  to  123 . The seal ring part  124  is sandwiched between an upper edge portion  140   a  of the element part  140  and a cover member  108  in a watertight manner. The cover member  108  consists of a cover main part  108   a  and two upper discoid parts  108   b ,  108   c . The diaphragm valves  121  to  123  are supported on an upper surface of the element part  140  via spacing members  171  to  173 , respectively. 
     Coil springs  151  to  153  (an example of an elastic member) are provided between the respective diaphragm valves  121  to  123  and a lower surface of the cover member  108 , so that each of the diaphragm valves  121  to  123  is biased in a valve-closing direction by means of the corresponding coil spring  151  to  153 . 
     The three diaphragm valves  121  to  123  of the present embodiment are also annularly arranged, and a pilot hole (a part of which is a back-pressure-chamber outlet hole  121   c  to  123   c  formed on a lower-surface side of the cover member  108 ) for communicating a back pressure chamber  121   b  to  123   b  of each of the three diaphragm valves  121  to  123  with a space below the element part  140 , which is a space outside the storage chamber  105 , is collectively located at a central region of the three diaphragm valves  121  to  123 , so that the pilot hole is opened and closed by a disc-shaped member  110 , which serves as a common pilot valve. (When the number of the plurality of diaphragm valves is two, a pilot hole for communicating a back pressure chamber of each of the two diaphragm valves with the space below the element part  140  may be collectively located at a middle region of the two diaphragm valves.) 
     The disc-shaped member  110  is also made of resin. The disc-shaped member  110  is supported in a rotatable manner around an axis thereof, and has twelve teeth  110   t  on an outer circumference thereof. 
       FIG.  12    is a schematic view for explaining an opened/closed state of a pilot hole, similarly to  FIG.  4   . The numeral signs in  FIG.  12    correspond to the numeral signs in  FIG.  4    added by 100, respectively. The disc-shaped member  110  also has four communication holes  110   h  (an example of the plurality of communication holes). As shown in  FIG.  12    schematically, each of the four communication holes  110   h  is configured to open a corresponding pilot hole of a corresponding diaphragm valve  121  to  123  when selectively communicating with a corresponding back-pressure-chamber outlet hole  121   c  to  123   c  provided on a corresponding back pressure chamber  121   b  to  123   b  of the corresponding diaphragm valve  121  to  123 , in response to a rotational position of the disc-shaped member  110 . More specifically, when each of the four communication holes  110   h  selectively communicates with the corresponding back-pressure-chamber outlet hole  121   c  to  123   c  and a corresponding outlet hole  144  to  146  in the element part  140  provided correspondingly to the corresponding back-pressure-chamber outlet hole  121   c  to  123   c , the corresponding pilot hole of the corresponding diaphragm valve  121  to  123  is opened. The four communication holes  110   h  are also annularly arranged at even intervals in a circumferential direction, i.e., every 90 degrees. The back-pressure-chamber outlet holes  121   c  to  123   c  and the outlet holes  144  to  146  are also annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. 
       FIG.  13    is a schematic view for explaining a disc-pushing member  130 , similarly to  FIG.  5   . The numeral signs in  FIG.  13    correspond to the numeral signs in  FIG.  5    added by 100, respectively. As shown in  FIG.  13    schematically, the disc-pushing member  130  is interposed between the back-pressure-chamber outlet holes  121   c  to  123   c  and the disc-shaped member  110 . The disc-pushing member  130  is configured to push the disc-shaped member  110  away from the back-pressure-chamber outlet holes  121   c  to  123   c  (toward the element part  140 ) by means of a coil spring  135  as an example of a biasing part. 
     The disc-pushing member  130  is provided with three outlet communication holes  131   c  to  133   c , each of which can communicate with the corresponding back-pressure-chamber outlet hole  121   c  to  123   c  provided on the corresponding back pressure chamber  121   b  to  123   b  of the corresponding diaphragm valve  121  to  123 . In the present embodiment as well, each of the outlet communication holes  131   c  to  133   c  is formed by a tubular part  131  to  133 , and each of the tubular parts  131  to  133  is inserted into the corresponding back-pressure-chamber outlet hole  121   c  to  123   c . There remains a gap between each of the tubular parts  131  to  133  and the corresponding back-pressure-chamber outlet hole  121   c  to  123   c , and the gap is configured to function as a corresponding back-pressure-chamber inlet hole. (However, at least at the time of filing the present application, the scope of the present invention does not exclude a manner wherein each of back-pressure-chamber inlet holes  121   d  to  123   d  is provided through a portion of the corresponding diaphragm valve  121  to  123 , as shown in  FIG.  12   ). 
     With reference to  FIG.  11    again, a push button  111  is provided on a lower portion of a shower head housing  107  as an operation part configured to receive an operation force from a user. (Any other type of button or slide switch may be provided in place of the push button  111 .) 
     Every time the push button  111  receives an operation force (a pushing force) from a user (every time the user gives an operation force (a pushing force) to the push button  111 ), the push button  111  pivots around a pivot shaft  111   s . Then, in coordination with the pivot movement, by means of abutment and slide between an abutment slide inclined portion  111   a  of the push button  111  and an abutment slide ring part  112   a  provided at a proximal end portion of a shaft part  112 , the shaft part  112  is configured to reciprocate in an axial direction thereof. 
     A distal end portion of the shaft part  112  is exposed to the water in the storage chamber  105  (see  FIG.  14   , too). Thus, the shaft part  112  is made of a metal bar which is difficult to rust, such as a stainless-steel bar. In the present embodiment as well, the shaft part  112  slidably pierces through the element part  140  integrally fixed to the shower head housing  107 . A seal ring part  112   s  is provided for maintaining watertight performance. 
       FIG.  14    is a schematic view for explaining a state wherein the disc-shaped member  110  has started to be rotated, similarly to  FIG.  6   . As shown in  FIG.  14   , a coil spring  114  is arranged around a distal end portion of the shaft part  112  located in the storage chamber  105 . A proximal end of the coil spring  114  is fixed to the element part  140 , and thus fixed to the shower head housing  107  (to the pivot shaft  111   s  of the push button  111 ). 
     A claw member  115  is fixed to a distal end of the coil spring  114 . A stopper  113  for the claw member  115  is attached to the distal end portion of the shaft part  112 . The distal end of the coil spring  114  and the claw member  115  are movable in an axial direction by deformation of the coil spring  114  in the axial direction in a region on the side of the proximal end portion of the shaft part  112  with respect to the stopper  113 . 
     Furthermore, the distal end of the coil spring  114  and the claw member  115  are also movable in an inclined direction, which is inclined with respect to the axial direction of the coil spring  114 , by deformation of the coil spring  114  in the inclined direction. 
     A claw  115   t  is provided on a lateral surface of the claw member  115  on the side of the disc-shaped member  110 . The claw  115   t  is configured to engage with the teeth  110   t  of the disc-shaped member  110 . The disc-shaped member  110  is rotated when the claw  115   t  draws one of the teeth  110   t  while the shaft part  112  reciprocates. 
     In addition, a stopper claw  116  configured to prevent the disc-shaped member  110  (teeth  110   t ) from reversely rotating is held by a stopper-claw fixing part  117  provided on the element part  140 . 
     Operation of Second Embodiment 
     Next, an operation of the shower head  101  according to the second embodiment is explained. 
     With reference to  FIG.  13   , when a user pushes the push button  111 , the pushing force (operating force) causes the abutment slide inclined portion  111   a  of the push button  111  to pivot around the pivot shaft  111   s , so that the shaft part  112  moves in a direction toward the proximal end portion thereof (the right side in  FIG.  13   ) via the abutment slide ring part  112   a.    
     The state shown in  FIG.  14    corresponds to a state before the user pushes the push button  111 . From this state, the shaft part  112  starts to move. When the claw  115   t  of the claw member  115  draws one of the teeth  110   t  of the disc-shaped member  110 , the disc-shaped member  110  is rotated (see  FIG.  7   , too). In the state wherein the push button  111  has been pushed to a deepest position thereof and thus the shaft part  112  has moved to a most proximal-end-side position thereof (rightmost position in  FIG.  13   ), the stopper claw  116  stops a tooth  110   t  next to that in  FIG.  14   . Accordingly, the disc-shaped member  110  is rotated by 30 degrees every time the user pushes the push button  111 . 
     In this state, the coil spring  114  is compressed between the claw member  115  (and the stopper  113  at the distal end portion of the shaft part  112 ) and the element part  140 . From this state, when the pushing force against the push button  111  is released, the shaft part  112  and the push button  111  are returned back to their original positions (the state shown in  FIG.  14   ) by a resilience force of the coil spring  114 . During this step, the claw  115   t  does not engage with any tooth  110   t , and the disc-shaped member  110  is not reversely rotated in combination with the existence of the claw stopper  116 . In addition, during the above step, the claw member  115  is movable in the inclined direction, which is inclined with respect to the axial direction of the coil spring  114 , by the deformation of the coil spring  114  in the inclined direction. Thus, it is possible to effectively avoid resistance (interference) from the disc-shaped member  110 . In addition, when the claw member  115  is returned back to an original position thereof (the state shown in  FIG.  14   ), the claw member  115  (claw  115   t ) engages with the tooth  110   t  next to the previously drawn one, by the resilience force of the coil spring  114 . 
     As described above, the four communication holes  110   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 90 degrees, and the back-pressure-chamber outlet holes  121   c  to  123   c  and the outlet holes  144  to  146  are annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. Thus, when the disc-shaped member  110  is rotated by 30 degrees, it is possible to sequentially switch the following three spout modes: 
     (i) a first spout mode wherein the back-pressure-chamber outlet holes  121   c  and the outlet hole  144  communicate with each other while the back-pressure-chamber outlet holes  122   c ,  123   c  and the outlet holes  145 ,  146  do not communicate with each other; 
     (ii) a second spout mode wherein the back-pressure-chamber outlet holes  122   c  and the outlet hole  145  communicate with each other while the back-pressure-chamber outlet holes  121   c ,  123   c  and the outlet holes  144 ,  146  do not communicate with each other; and 
     (iii) a third spout mode wherein the back-pressure-chamber outlet holes  123   c  and the outlet hole  146  communicate with each other while the back-pressure-chamber outlet holes  121   c ,  122   c  and the outlet holes  144 ,  145  do not communicate with each other. 
     The state shown in the right side half of  FIG.  12    or  FIG.  13    is an example of a state wherein a back-pressure-chamber outlet hole and the corresponding outlet hole do not communicate with each other, i.e., the corresponding pilot hole of the corresponding diaphragm valve is not opened. In the state shown in the right side half of  FIG.  12    or  FIG.  13   , the back-pressure-chamber outlet holes  122   c ,  123   c  and the corresponding outlet holes  145 ,  146  are blocked by the disc-shaped member  110 . On the other hand, through the back-pressure-chamber inlet holes  122   d ,  123   d  (in the case shown in  FIG.  12   ) or through the gaps between the tubular parts  132 ,  133  and the corresponding back-pressure-chamber outlet holes  122   c ,  123   c  (in the case shown in  FIG.  13   ), the water pressure in the storage chamber  105  and the water pressures in the back pressure chambers  123   b ,  123   c  are made equal to each other. Thus, each of the diaphragm valves  122 ,  123  is closed by a biasing force of the corresponding coil spring  152 ,  153  (not shown in  FIGS.  12  and  13   ). 
     The state shown in the left side half of  FIG.  12    or  FIG.  13    is an example of a state wherein a back-pressure-chamber outlet hole and the corresponding outlet hole communicate with each other, i.e., the corresponding pilot hole of the corresponding diaphragm valve is opened. In the state shown in the left side half of  FIG.  12    or  FIG.  13   , the back-pressure-chamber outlet hole  121   c  and the corresponding outlet hole  144  communicate with each other through the communication hole  110   h  of the disc-shaped member  110 . In this state, the water in the back pressure chamber  121   b  flows out through the back-pressure-chamber outlet hole  121   c  and the corresponding outlet hole  144 , so that the water pressure in the storage chamber  105  becomes greater than the water pressure in the back pressure chamber  121   b . Thus, the diaphragm valve  121  is opened in spite of the biasing force of the corresponding coil spring  151  (not shown in  FIGS.  12  and  13   ). 
     Effects of Second Embodiment 
     As described above, according to the shower head  101  of the second embodiment as well, since the communicated/blocked state between each of the three flow paths and the storage chamber  105  is controlled by each of the three diaphragm valves  121  to  123 , a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
     In particular, according to the shower head  101  of the second embodiment, the pilot hole for communicating the back pressure chamber  121   b  to  123   b  of each of the annularly-arranged three diaphragm valves  121  to  123  with the space outside the storage chamber  105  is collectively located at the central region of the three diaphragm valves  121  to  123  so that the pilot hole is opened and closed by the common disc-shaped member  110  (pilot valve). Thus, the shower head  101  is made to be compact. In addition, a moving range (moving distance) of the disc-shaped member  110  (pilot valve) is sufficiently small, which contributes to a further reduction of the operating force. 
     In addition, according to the shower head  101  of the second embodiment, the disc-shaped member  110  is supported in a rotatable manner around the axis thereof and has the teeth  110   t  on the outer circumference thereof. Thus, it is possible to easily drive the disc-shaped member  110  in rotation by using the teeth  110   t.    
     In addition, according to the shower head  101  of the second embodiment, the disc-shaped member  110  is made of resin. Thus, it is possible to easily achieve high smoothness, which can inhibit sliding resistance (sliding friction). In addition, it is unnecessary to separately provide a seal part. 
     In addition, according to the shower head  101  of the second embodiment, the disc-shaped member  110  has the four communication holes  110   h , and each of the four communication holes  110   h  is configured to open the corresponding pilot hole of the corresponding diaphragm valve  121  to  123  when selectively communicating with the corresponding back-pressure-chamber outlet hole  121   c  to  123   c  provided on the corresponding back pressure chamber  121   b  to  123   b  of the corresponding diaphragm valve  121  to  123 , in response to a rotational position of the disc-shaped member  110 . Thus, the shower head  101  is made to be more compact. In addition, a rotation angle (moving distance) of the disc-shaped member  110  (pilot valve) is sufficiently small (no more than 30 degrees), which contributes to a further reduction of the operating force. 
     In addition, according to the shower head  101  of the second embodiment, the disc-pushing member  130  is interposed between the corresponding back-pressure-chamber outlet hole  121   c  to  123   c  and the disc-shaped member  110 , the disc-pushing member  130  has the outlet communication holes  131   c  to  133   c  each of which can communicate with the corresponding back-pressure-chamber outlet hole  121   c  to  123   c  provided on the corresponding back pressure chamber  121   b  to  123   b  of the corresponding diaphragm valve  121  to  123 , and the disc-pushing member  130  is configured to push the disc-shaped member  110  away from the corresponding back-pressure-chamber outlet hole  121   c  to  123   c  by means of the coil spring  135 . Thus, it is unnecessary to provide a seal part between the disc-shaped member  110  and the element part  140  (a member located away from the back-pressure-chamber outlet holes  121   c  to  123   c  with respect to the disc-shaped member  110 ). 
     In particular, according to the shower head  101  of the second embodiment, each of the outlet communication holes  131   c  to  133   c  is formed by the corresponding tubular part  131  to  133 , each of the tubular parts  131  to  133  is inserted into the corresponding back-pressure-chamber outlet hole  121   c  to  123   c , the gap between each of the tubular parts  131  to  133  and the corresponding back-pressure-chamber outlet hole  121   c  to  123   c  is configured to function as a corresponding back-pressure-chamber inlet hole. It is easy to form the gap with high precision, and thus it is possible to effectively inhibit variation in performance among the three back-pressure-chamber inlet holes (the three gaps) for the three diaphragm valves  121  to  123 . 
     In addition, according to the shower head  101  of the second embodiment, by using a driving mechanism including: the push button  111  configured to receive an operation force from a user; the shaft part  112  configured to reciprocate in the axial direction thereof every time the push button  111  receives the operation force; and the claw member  115  attached to the distal end portion of the shaft part  112  and having the claw  115   t  configured to engage with the teeth  110   t  of the disc-shaped member  110 , the disc-shaped member  110  is rotated when the claw  115   t  draws one of the teeth  110   t  while the shaft part  112  reciprocates. Since the force for driving the disc-shaped member  110  in rotation is applied in a direction in which the claw  115   t  draws one of the teeth  110   t , it is possible to prevent (avoid) buckling deformation of the shaft part  112 . Thus, rigidity required for the shaft part  112  can be reduced. As a result, it is possible to make the shaft part  112  of not only a rigid material but also a plastic material such as string or an elastic material such as rubber. 
     In particular, according to the shower head  101  of the second embodiment, the proximal end portion of the shaft part  112  is operably connected to the push button part  111 , the coil spring  114  is arranged around the distal end portion of the shaft part  112 , the proximal end of the coil spring  114  is fixed to the element part  140 , the distal end of the coil spring  114  is fixed to the claw member  115 , and the stopper  113  for the claw member  115  is attached to the distal end portion of the shaft part  112 . Thus, the claw member  115  is movable relative to the shaft part  112  by deformation of the coil spring  114  (both in the axial direction and in the inclined direction). Thus, after the claw member  115  has drawn one tooth  110   t , when the claw member  115  is returned to the original position thereof (the state shown in  FIG.  14   ) to engage with the next tooth  110   t , it is possible to effectively avoid resistance (interference) from the disc-shaped member  110 . 
     In addition, according to the shower head  101  of the second embodiment, the three diaphragm valves  21  to  23  are separate independent members. Thus, the three diaphragm valves  21  to  23  are replaceable independent of each other. 
     In addition, according to the shower head  101  of the second embodiment, each of the three diaphragm valves  121  to  123  is biased in a valve-closing direction by means of the corresponding coil spring  151  to  153 . Thus, the movement for opening and closing each of the three diaphragm valves  121  to  123  is stabilized. 
     [Complement Regarding Flow Paths] 
     In the shower heads  1 ,  101  of the above embodiments, the opened/closed state of each of the three diaphragm valves  21  to  23 ,  121  to  123  corresponds to the communicated/blocked state of each of the three flow paths in the secondary-side flow-path member  4 ,  104  on a one-to-one basis, and just one diaphragm valve is opened at a time in response to a rotational position of the disc-shaped member  10 ,  110 , so that just one flow path is communicated at the time. However, the present invention is not limited to this matter, 
     For example, by changing an arrangement pattern of the communication holes  10   h ,  110   h  of the disc-shaped member  10 ,  110 , a plurality of diaphragm valves may be opened at the same time in response to a rotational position of the disc-shaped member  10 ,  110 , so that a plurality of flow paths may be communicated at the same time to achieve a composite-type spout. 
     Alternatively, for example, by changing an arrangement pattern of the flow paths in the secondary-side flow-path member  4 ,  104 , a plurality of flow paths may be communicated at the same time to achieve a composite-type spout when a specific diaphragm valve is opened. 
     Furthermore, by changing an arrangement pattern of the communication holes  10   h ,  110   h  of the disc-shaped member  10 ,  110 , all the diaphragm valves may be closed at the same time in response to a rotational position of the disc-shaped member  10 ,  110 , so that all the flow paths may be blocked at the same time to achieve a temporal water stop. That is to say, by means of such a structure, it is possible to achieve a temporal water stop by operating the push button  11 ,  111 . 
     Variation of Second Embodiment 
     The shower head  101  of the second embodiment is a shower head for which a plurality of spout modes can be switched (water can be discharged in each of the plurality of spout modes) by using the three separate diaphragm valves  121  to  123  (an example of main valve body). 
     In the second embodiment, each of the diaphragm valves  121  to  123  may be replaced with a piston valve (another example of main valve body). 
       FIG.  15    is a schematic view, corresponding to  FIG.  13   , for explaining a structure wherein the diaphragm valves  121  to  123  are replaced with piston valves  221  to  223 , respectively. 
     In the variation shown in  FIG.  15   , each of the piston valves  221  to  232  is slidably provided in a corresponding slide guide cylinder  271  to  273  provided on the cover main body  108   a  via a corresponding water-tight ring part  261  to  263 . 
     Coil springs  251  to  253  (an example of an elastic member) are provided between the respective piston valves  221  to  223  and a lower surface of the cover main body  108   a , so that each of the piston valves  221  to  223  is biased in a valve-closing direction by means of the corresponding coil spring  251  to  253 . 
     According to the above variation as well, it is possible to achieve the same effects as the shower head  101  of the second embodiment. 
     Specifically, in the state wherein a pilot hole of the corresponding piston valve  222 ,  223  is not opened (the state shown in the right side half of  FIG.  16   ), i.e., in the state wherein a back-pressure-chamber outlet hole  222   c ,  223   c  and the corresponding outlet hole  45 ,  46  are blocked by the disc-shaped member  10 , through the gap (back-pressure-chamber inlet hole) between the corresponding tubular part  32 ,  33  and the corresponding back-pressure-chamber outlet hole  222   c ,  223   c , the water pressure in the storage chamber  105  and the water pressure in the back pressure chamber  223   b ,  223   c  are made equal to each other. Thus, each of the piston valves  222 ,  223  is closed by a biasing force of the corresponding coil spring  252 ,  253 . 
     On the other hand, in the state wherein a pilot hole of the corresponding piston valve  221  is opened (the state shown in the left side half of  FIG.  16   ), i.e., in the state wherein a back-pressure-chamber outlet hole  221   c  and the corresponding outlet hole  44  communicate with each other through the corresponding communication hole  10   h  of the disc-shaped member  10 , the water in the back pressure chamber  221   b  flows out through the back-pressure-chamber outlet hole  221   c  and the corresponding outlet hole  44 , so that the water pressure in the storage chamber  105  becomes greater than the water pressure in the back pressure chamber  221   b . Thus, the piston valve  221  is opened in spite of the biasing force of the corresponding coil spring  251 . 
     Structure of Third Embodiment 
     As described above, the shower head  1  of the first embodiment is a shower head for which a plurality of spout modes can be switched (water can be discharged in each of the plurality of spout modes). If only one spout mode among the plurality of spout modes is limited and used, the shower head  1  is also a shower head for which the only one spout mode and a water-stop mode can be switched. That is to say, the disclosure of the shower head  1  of the first embodiment serves as a disclosure of a shower head for which a spout mode and a water-stop mode can be switched (see paragraph 0120). 
     However, for promoting a better understanding, a shower head according to a third embodiment of the present invention will be described with reference to the attached drawings. The shower head  301  according to the third embodiment is a shower head for which only one spout mode and a water-stop mode can be switched (water can be discharged in the one spout mode). 
       FIG.  16    is a partially sectional perspective view of the shower head  301  according to the third embodiment of the present invention,  FIG.  17    is a partially longitudinal section view of the shower head  301  shown in  FIG.  16   , and  FIG.  18    is an exploded perspective view of the shower head shown in  FIG.  16   . 
     As shown in  FIGS.  16  to  18   , the shower head  301  of the third embodiment includes a storage chamber  5  (which is also called cavity) configured to store water supplied from a water supply source (not shown) through water supply members  2 ,  3 , similarly to the shower head  1  of the first embodiment. 
     A secondary-side flow-path member  304  is provided on a spout-surface side of the shower head  301  with respect to the storage chamber  5 . The secondary-side flow-path member  304  consists of one or more substantially discoid element parts. The secondary-side flow-path member  304  has only one flow path which corresponds to only one spout mode. 
     Three valve seats  341  to  343  protruded on a side of the storage chamber  5  are formed on a portion of the secondary-side flow-path member  304  facing to the storage chamber  5 . A communication hole that communicates with the one flow path is provided at a center of each of the valve seats  341  to  343  (see  FIG.  4   , too). The three valve seats  341  to  343  (and their corresponding communication holes) are annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. 
     Three diaphragm valves  21  to  23 , which correspond to the three valve seats  341  to  343 , respectively, are annularly arranged, similarly to the shower head  1  of the first embodiment. The three diaphragm valves  21  to  23  are integrally formed as one diaphragm member  20 . However, the respective diaphragm valves  21  to  23  are movable independently of each other. 
     A seal ring portion  24  is formed at a periphery of the diaphragm member  20 . The seal ring portion  24  is sandwiched between an upper edge portion of the secondary-side flow-path member  304  and a cover member  8  in a watertight manner. A central area of the diaphragm member  20  is supported on an upper surface of the secondary-side flow-path member  304  via a spacing member  38 . 
     Similarly to the shower head  1  of the first embodiment, coil springs  51  to  53  (an example of an elastic member) are provided between the respective diaphragm valves  21  to  23  and a lower surface of the cover member  8 , so that each of the diaphragm valves  21  to  23  is biased in a valve-closing direction by means of the corresponding coil spring  51  to  53 . 
     The three diaphragm valves  21  to  23  of the present embodiment are annularly arranged, and a pilot hole (a part of which is a back-pressure-chamber outlet hole  21   c  to  23   c  formed on a lower-surface side of the cover member  8 ) for communicating a back pressure chamber  21   b  to  23   b  of each of the three diaphragm valves  21  to  23  with a space in the secondary-side flow-path member  304 , which is a space outside the storage chamber  5 , is collectively located at a central region of the three diaphragm valves  21  to  23 , so that the pilot hole is opened and closed by a disc-shaped member  10 , which serves as a common pilot valve. (When the number of the plurality of diaphragm valves is two, a pilot hole for communicating a back pressure chamber of each of the two diaphragm valves with the space in the secondary-side flow-path member  304  may be collectively located at a middle region of the two diaphragm valves.) 
     Similarly to the shower head  1  of the first embodiment, the disc-shaped member  310  is made of resin. The disc-shaped member  310  is supported in a rotatable manner around an axis thereof, and has twelve teeth  310   t  on an outer circumference thereof (see  FIGS.  6  to  8   , too). 
     An opened/closed state of a pilot hole of the present embodiment is substantially the same as that of the first embodiment, and is explained with reference to  FIG.  4    just in case. The valve seats  41  to  43  in  FIG.  4    correspond to the valve seats  341  to  343  in the present embodiment, and the disc-shaped member  10  and the communication holes  10   h  in  FIG.  4    substantially correspond to the disc-shaped member  310  and the communication holes  310   h  in the present embodiment. The disc-shaped member  310  has six communication holes  310   h  (four communication holes  10   h  in the first embodiment). As shown in  FIG.  4    schematically, each of the six communication holes  310   h  is configured to open a corresponding pilot hole of a corresponding diaphragm valve  21  to  23  when selectively communicating with a corresponding back-pressure-chamber outlet hole  21   c  to  23   c  provided on a corresponding back pressure chamber  21   b  to  23   b  of the corresponding diaphragm valve  21  to  23 , in response to a rotational position of the disc-shaped member  310 . More specifically, when each of the six communication holes  310   h  selectively communicates with the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  and a corresponding outlet hole  44  to  46  in the secondary-side flow-path member  304  provided correspondingly to the corresponding back-pressure-chamber outlet hole  21   c  to  23   c , the corresponding pilot hole of the corresponding diaphragm valve  21  to  23  is opened. The six communication holes  310   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 60 degrees. The back-pressure-chamber outlet holes  21   c  to  23   c  and the outlet holes  44  to  46  are also annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. 
     A disc-pushing member  30  of the present embodiment is substantially the same as that of the first embodiment, and is explained with reference to  FIG.  5    just in case. The valve seats  41  to  43  in  FIG.  5    correspond to the valve seats  341  to  343  in the present embodiment, and the disc-shaped member  10  and the communication holes  10   h  in  FIG.  5    substantially correspond to the disc-shaped member  310  and the communication holes  310   h  in the present embodiment. As shown in  FIG.  5    schematically, the disc-pushing member  30  is interposed between the back-pressure-chamber outlet holes  21   c  to  23   c  and the disc-shaped member  310 . The disc-pushing member  30  is configured to push the disc-shaped member  310  away from the back-pressure-chamber outlet holes  21   c  to  23   c  (toward the secondary-side flow-path member  304 ) by means of a coil spring  35  as an example of a biasing part. 
     The disc-pushing member  30  is provided with three outlet communication holes  31   c  to  33   c , each of which can communicate with the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  provided on the corresponding back pressure chamber  21   b  to  23   b  of the corresponding diaphragm valve  21  to  23 . In the present embodiment, each of the outlet communication holes  31   c  to  33   c  is formed by a tubular part  31  to  33 . Each of the tubular parts  31  to  33  is inserted into the corresponding back-pressure-chamber outlet hole  21   c  to  23   c . There remains a gap between each of the tubular parts  31  to  33  and the corresponding back-pressure-chamber outlet hole  21   c  to  23   c , and the gap is configured to function as a corresponding back-pressure-chamber inlet hole. (However, at least at the time of filing the present application, the scope of the present invention does not exclude a manner wherein each of back-pressure-chamber inlet holes  21   d  to  23   d  is provided through a portion of the corresponding diaphragm valve  21  to  23 , as shown in  FIG.  4   ). 
     With reference to  FIG.  17    again, similarly to the shower head  1  of the first embodiment, a push button  11  is provided on a lower portion of a shower head housing  7  as an operation part configured to receive an operation force from a user. (Any other type of button or slide switch may be provided in place of the push button  11 .) 
     Every time the push button  11  receives an operation force (a pushing force) from a user (every time the user gives an operation force (a pushing force) to the push button  11 ), the push button  11  pivots around a pivot shaft  11   s . Then, in coordination with the pivot movement, by means of abutment and slide between an abutment slide inclined portion  11   a  of the push button  11  and an abutment slide ring part  12   a  provided at a proximal end portion of a shaft part  12 , the shaft part  12  is configured to reciprocate in an axial direction thereof. 
     A distal end portion of the shaft part  12  is exposed to the water in the storage chamber  5  (see  FIGS.  6  to  8   , too). Thus, the shaft part  12  is made of a metal bar which is difficult to rust, such as a stainless-steel bar. In the present embodiment, the shaft part  12  slidably pierces through the secondary-side flow-path member  304  integrally fixed to the shower head housing  7 . A seal ring part  12   s  is provided for maintaining watertight performance. The shaft part  12  may be made of not only a rigid material but also a plastic material such as string or an elastic material such as rubber. 
     A state wherein the disc-shaped member  310  has started to be rotated is substantially the same as that of the first embodiment, and is explained with reference to  FIGS.  6  to  8    just in case. The element part  40  in  FIGS.  6  to  8    corresponds to the secondary-side flow-path member  304  in the present embodiment, and the disc-shaped member  10 , the communication holes  10   h  and the teeth  10   t  in  FIGS.  6  to  8    substantially correspond to the disc-shaped member  310 , the communication holes  310   h  and the teeth  310   t  in the present embodiment. 
     As shown in  FIGS.  6  to  8   , a coil spring  14  is arranged around a distal end portion of the shaft part  12  located in the storage chamber  5 . A proximal end of the coil spring  14  is fixed to the secondary-side flow-path member  304 , and thus fixed to the shower head housing  7  (to the pivot shaft  11   s  of the push button  11 ). 
     A claw member  15  is fixed to a distal end of the coil spring  14 . A stopper  13  for the claw member  15  is attached to the distal end portion of the shaft part  12 . The distal end of the coil spring  14  and the claw member  15  are movable in an axial direction by deformation of the coil spring  14  in the axial direction in a region on the side of the proximal end portion of the shaft part  12  with respect to the stopper  13 . 
     Furthermore, the distal end of the coil spring  14  and the claw member  15  are also movable in an inclined direction, which is inclined with respect to the axial direction of the coil spring  14 , by deformation of the coil spring  14  in the inclined direction. 
     A claw  15   t  is provided on a lateral surface of the claw member  15  on the side of the disc-shaped member  310 . The claw  15   t  is configured to engage with the teeth  310   t  of the disc-shaped member  310 . The disc-shaped member  310  is rotated when the claw  15   t  draws one of the teeth  310   t  while the shaft part  12  reciprocates (from the state shown in  FIG.  6   , through the stage shown in  FIG.  7   , to the state sown in  FIG.  8   ). 
     In addition, a stopper claw  16  configured to prevent the disc-shaped member  310  (teeth  310   t ) from reversely rotating is held by a stopper-claw fixing part  17  provided on the secondary-side flow-path member  304 . 
     Operation of Third Embodiment 
     Next, an operation of the shower head  301  according to the third embodiment is explained. 
     With reference to  FIG.  17   , when a user pushes the push button  11 , the pushing force (operating force) causes the abutment slide inclined portion  11   a  of the push button  11  to pivot around the pivot shaft  11   s , so that the shaft part  12  moves in a direction toward the proximal end portion thereof (the right side in  FIG.  17   ) via the abutment slide ring part  12   a.    
     The state shown in  FIG.  6    corresponds to a state before the user pushes the push button  11 . From this state, the shaft part  12  starts to move. When the claw  15   t  of the claw member  15  draws one of the teeth  310   t  of the disc-shaped member  310 , the disc-shaped member  310  is rotated, as shown in  FIG.  7   . The state shown in  FIG.  8    corresponds to a state wherein the push button  11  has been pushed to a deepest position thereof and thus the shaft part  12  has moved to a most proximal-end-side position thereof (rightmost position in  FIG.  17   ). In the state shown in  FIG.  8   , the stopper claw  16  stops a tooth  310   t  next to that in  FIG.  6   . Accordingly, the disc-shaped member  310  is rotated by 30 degrees every time the user pushes the push button  11 . 
     In the state shown in  FIG.  8   , the coil spring  14  is compressed between the claw member  15  (and the stopper  13  at the distal end portion of the shaft part  12 ) and the secondary-side flow-path member  304 . From this state, when the pushing force against the push button  11  is released, the shaft part  12  and the push button  11  are returned back to their original positions (the state shown in  FIG.  6   ) by a resilience force of the coil spring  14 . During this step, the claw  15   t  does not engage with any tooth  310   t , and the disc-shaped member  310  is not reversely rotated in combination with the existence of the claw stopper  16 . In addition, during the above step, the claw member  15  is movable in the inclined direction, which is inclined with respect to the axial direction of the coil spring  14 , by the deformation of the coil spring  14  in the inclined direction. Thus, it is possible to effectively avoid resistance (interference) from the disc-shaped member  310 . In addition, when the claw member  15  is returned back to an original position thereof (the state shown in  FIG.  6   ), the claw member  15  (claw  15   t ) engages with the tooth  310   t  next to the previously drawn one, by the resilience force of the coil spring  14 . 
     As described above, the six communication holes  310   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 60 degrees, and the back-pressure-chamber outlet holes  21   c  to  23   c  and the outlet holes  44  to  46  are annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. Thus, when the disc-shaped member  310  is rotated by 30 degrees, it is possible to sequentially switch the spout mode, in which the back-pressure-chamber outlet holes  21   c  to  23   c  and the outlet holes  44  to  46  communicate with each other in three pairs (whose combination is free) at the same time, and the water-stop mode, in which the back-pressure-chamber outlet holes  21   c  to  23   c  and the outlet holes  44  to  46  do not communicate with each other. 
     The state shown in the right side half of  FIG.  4    or  FIG.  5    is an example of a state wherein a back-pressure-chamber outlet hole and the corresponding outlet hole do not communicate with each other, i.e., the corresponding pilot hole of the corresponding diaphragm valve is not opened. In the state shown in the right side half of  FIG.  4    or  FIG.  5   , the back-pressure-chamber outlet holes  22   c ,  23   c  and the corresponding outlet holes  45 ,  46  are blocked by the disc-shaped member  310 . On the other hand, through the back-pressure-chamber inlet holes  22   d ,  23   d  (in the case shown in  FIG.  4   ) or through the gaps between the tubular parts  32 ,  33  and the corresponding back-pressure-chamber outlet holes  22   c ,  23   c  (in the case shown in  FIG.  5   ), the water pressure in the storage chamber  5  and the water pressures in the back pressure chambers  23   b ,  23   c  are made equal to each other. Thus, each of the diaphragm valves  22 ,  23  is closed by a biasing force of the corresponding coil spring  52 ,  53  (not shown in  FIGS.  4  and  5   ). 
     The state shown in the left side half of  FIG.  4    or  FIG.  5    is an example of a state wherein a back-pressure-chamber outlet hole and the corresponding outlet hole communicate with each other, i.e., the corresponding pilot hole of the corresponding diaphragm valve is opened. In the state shown in the left side half of  FIG.  4    or  FIG.  5   , the back-pressure-chamber outlet hole  21   c  and the corresponding outlet hole  44  communicate with each other through the communication hole  310   h  of the disc-shaped member  310 . In this state, the water in the back pressure chamber  21   b  flows out through the back-pressure-chamber outlet hole  21   c  and the corresponding outlet hole  44 , so that the water pressure in the storage chamber  5  becomes greater than the water pressure in the back pressure chamber  21   c . Thus, the diaphragm valve  21  is opened in spite of the biasing force of the corresponding coil spring  51  (not shown in  FIGS.  4  and  5   ). 
     Effects of Third Embodiment 
     As described above, according to the shower head  301  of the third embodiment, since the communicated/blocked state between the flow path in the secondary-side flow-path member  304  and the storage chamber  5  is controlled by the three diaphragm valves  21  to  23 , a remarkable and stable reduction of an operation force for the switching operation between the spout mode and the water-stop mode is achieved. 
     In particular, according to the shower head  301  of the third embodiment, the pilot hole for communicating the back pressure chamber  21   b  to  23   b  of each of the annularly-arranged three diaphragm valves  21  to  23  with the space outside the storage chamber  5  is collectively located at the central region of the three diaphragm valves  21  to  23  so that the pilot hole is opened and closed by the common disc-shaped member  310  (pilot valve). Thus, the shower head  301  is made to be compact. In addition, a moving range (moving distance) of the disc-shaped member  310  (pilot valve) is sufficiently small, which contributes to a further reduction of the operating force. 
     In addition, according to the shower head  301  of the third embodiment, the disc-shaped member  310  is supported in a rotatable manner around the axis thereof and has the teeth  310   t  on the outer circumference thereof. Thus, it is possible to easily drive the disc-shaped member  310  in rotation by using the teeth  310   t.    
     In addition, according to the shower head  301  of the third embodiment, the disc-shaped member  310  is made of resin. Thus, it is possible to easily achieve high smoothness, which can inhibit sliding resistance (sliding friction). In addition, it is unnecessary to separately provide a seal part. 
     In addition, according to the shower head  301  of the third embodiment, the disc-shaped member  310  has the six communication holes  310   h , and each of the six communication holes  310   h  is configured to open the corresponding pilot hole of the corresponding diaphragm valve  21  to  23  when selectively communicating with the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  provided on the corresponding back pressure chamber  21   b  to  23   b  of the corresponding diaphragm valve  21  to  23 , in response to a rotational position of the disc-shaped member  310 . Thus, the shower head  301  is made to be more compact. In addition, a rotation angle (moving distance) of the disc-shaped member  310  (pilot valve) is sufficiently small (no more than 30 degrees), which contributes to a further reduction of the operating force. 
     In addition, according to the shower head  301  of the third embodiment, the disc-pushing member  30  is interposed between the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  and the disc-shaped member  310 , the disc-pushing member  30  has the outlet communication holes  31   c  to  33   c  each of which can communicate with the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  provided on the corresponding back pressure chamber  21   b  to  23   b  of the corresponding diaphragm valve  21  to  23 , and the disc-pushing member  30  is configured to push the disc-shaped member  310  away from the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  by means of the coil spring  35 . Thus, it is unnecessary to provide a seal part between the disc-shaped member  310  and the secondary-side flow-path member  304  (a member located away from the back-pressure-chamber outlet holes  21   c  to  23   c  with respect to the disc-shaped member  310 ). 
     In particular, according to the shower head  301  of the third embodiment, each of the outlet communication holes  31   c  to  33   c  is formed by the corresponding tubular part  31  to  33 , each of the tubular parts  31  to  33  is inserted into the corresponding back-pressure-chamber outlet hole  21   c  to  23   c , the gap between each of the tubular parts  31  to  33  and the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  is configured to function as a corresponding back-pressure-chamber inlet hole. It is easy to form the gap with high precision, and thus it is possible to effectively inhibit variation in performance among the three back-pressure-chamber inlet holes (the three gaps) for the three diaphragm valves  21  to  23 . 
     In addition, according to the shower head  301  of the third embodiment, by using a driving mechanism including: the push button  11  configured to receive an operation force from a user; the shaft part  12  configured to reciprocate in the axial direction thereof every time the push button  11  receives the operation force; and the claw member  15  attached to the distal end portion of the shaft part  12  and having the claw  15   t  configured to engage with the teeth  310   t  of the disc-shaped member  310 , the disc-shaped member  310  is rotated when the claw  15   t  draws one of the teeth  310   t  while the shaft part  12  reciprocates. Since the force for driving the disc-shaped member  310  in rotation is applied in a direction in which the claw  15   t  draws one of the teeth  310   t , it is possible to prevent (avoid) buckling deformation of the shaft part  12 . Thus, rigidity required for the shaft part  12  can be reduced. As a result, it is possible to make the shaft part  12  of not only a rigid material but also a plastic material such as string or an elastic material such as rubber. 
     In particular, according to the shower head  301  of the third embodiment, the proximal end portion of the shaft part  12  is operably connected to the push button part  11 , the coil spring  14  is arranged around the distal end portion of the shaft part  12 , the proximal end of the coil spring  14  is fixed to the secondary-side flow-path member  304 , the distal end of the coil spring  14  is fixed to the claw member  15 , and the stopper  13  for the claw member  15  is attached to the distal end portion of the shaft part  12 . Thus, the claw member  15  is movable relative to the shaft part  12  by deformation of the coil spring  14  (both in the axial direction and in the inclined direction). Thus, after the claw member  15  has drawn one tooth  310   t , when the claw member  15  is returned to the original position thereof (the state shown in  FIG.  6   ) to engage with the next tooth  310   t , it is possible to effectively avoid resistance (interference) from the disc-shaped member  310 . 
     In addition, according to the shower head  301  of the third embodiment, the three diaphragm valves  21  to  23  are integrally formed as the one diaphragm member  20 , and the seal ring portion  24  is provided at the periphery of the diaphragm member  20 . Thus, it is unnecessary to separately provide a seal ring part. 
     In addition, according to the shower head  301  of the third embodiment, each of the three diaphragm valves  21  to  23  is biased in a valve-closing direction by means of the corresponding coil spring  51  to  53 . Thus, the movement for opening and closing each of the three diaphragm valves  21  to  23  is stabilized. 
     According to the above structure as well, since the three diaphragm valves (main valve bodies) are respectively opened and closed by switching the opened/closed states of the three pilot holes by means of the disc-shaped member  310  (pilot valve), a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
     First Variation of Third Embodiment 
     As described above, the shower head  301  of the third embodiment is a shower head for which the spout mode and the water-stop mode can be switched by using the three separate diaphragm valves  21  to  23 . Each of the three separate diaphragm valves  21  to  23  is opened when the corresponding back-pressure-chamber outlet hole  21   c  to  23   c  and the corresponding outlet hole  44  to  46  communicate with each other through the corresponding communication hole  310   h  of the disc-shaped member  310 . 
     The three back pressure chambers  21   b  to  23   b  for the three separate diaphragm valves  21  to  23  may be connected to communicate with each other, and only one common back-pressure-chamber outlet hole may be provided for the three back pressure chambers  21   b  to  23   b . For example, only one of the three back-pressure-chamber outlet holes  21   c  to  23   c  may be provided, and correspondingly only one of the three outlet holes  44  to  46  may be provided. 
     In this case, as well as the shower head  301  of the third embodiment, if the six communication holes  310   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 60 degrees, when the disc-shaped member  310  is rotated by 30 degrees, it is possible to sequentially switch the spout mode, in which the only one back-pressure-chamber outlet hole and the only one outlet hole communicate with each other, and the water-stop mode, in which the only one back-pressure-chamber outlet hole and the only one outlet hole do not communicate with each other. 
     In the water-stop mode, i.e., in the state wherein the back-pressure-chamber outlet hole (one of the back-pressure-chamber outlet holes  21   c  to  23   c ) and the outlet hole (one of the outlet hole  44  to  46 ) are blocked by the disc-shaped member  310  (the state shown in the right side half of  FIG.  4    or  FIG.  5   ), the water pressure in the storage chamber  5  and the water pressure in the back pressure chamber are made equal to each other through a back-pressure-chamber inlet hole. Thus, each of the diaphragm valves  21  to  23  is closed by a biasing force of the corresponding coil spring (not shown in  FIGS.  4  and  5   ). 
     In the spout mode, i.e., in the state wherein the back-pressure-chamber outlet hole (one of the back-pressure-chamber outlet holes  21   c  to  23   c ) and the outlet hole (one of the outlet hole  44  to  46 ) communicate with each other through the communication hole  310   h  of the disc-shaped member  310  (the state shown in the left side half of  FIG.  4    or  FIG.  5   ), the water in the back pressure chamber flows out through the back-pressure-chamber outlet hole and the outlet hole, so that the water pressure in the storage chamber  5  becomes greater than the water pressure in the back pressure chamber. Thus, each of the diaphragm valves  21  to  23  is opened in spite of the biasing force of the corresponding coil spring (not shown in  FIGS.  4  and  5   ). 
     According to the above structure, since the three diaphragm valves (main valve bodies) are simultaneously opened and closed by switching the opened/closed state of the one pilot hole by means of the disc-shaped member  310  (pilot valve), a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
     Second Variation of Third Embodiment 
     Furthermore, in a shower head for which the spout mode and the water-stop mode can be switched, instead of the three diaphragm valves  21  to  23 , only one diaphragm valve (for example, one of the three diaphragm valves  21  to  23 , or another large-sized diaphragm valve replacing the three diaphragm valves  21  to  23 ) may be provided, and correspondingly, instead of the three valve seats  341  to  343 , only one valve seat (for example, one of the three valve seats  341  to  343 , or another large-sized valve seat) may be provided. 
     In this case, as well as the shower head  301  of the third embodiment, if the six communication holes  310   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 60 degrees, when the disc-shaped member  310  is rotated by 30 degrees, it is possible to sequentially switch the spout mode, in which a back-pressure-chamber outlet hole provided for the one diaphragm valve and a corresponding outlet hole communicate with each other, and the water-stop mode, in which the back-pressure-chamber outlet hole and the corresponding outlet hole do not communicate with each other. 
     In the water-stop mode, i.e., in the state wherein the back-pressure-chamber outlet hole provided for the one diaphragm valve and the corresponding outlet hole are blocked by the disc-shaped member  310  (the state shown in the right side half of  FIG.  4    or  FIG.  5   ), the water pressure in the storage chamber  5  and the water pressure in the back pressure chamber are made equal to each other through a back-pressure-chamber inlet hole provided for the one diaphragm valve. Thus, the one diaphragm valve is closed by a biasing force of a corresponding coil spring (not shown in  FIGS.  4  and  5   ). 
     In the spout mode, i.e., in the state wherein the back-pressure-chamber outlet hole provided for the one diaphragm valve and the outlet hole communicate with each other through the communication hole  310   h  of the disc-shaped member  310  (the state shown in the left side half of  FIG.  4    or  FIG.  5   ), the water in the back pressure chamber flows out through the back-pressure-chamber outlet hole and the outlet hole, so that the water pressure in the storage chamber  5  becomes greater than the water pressure in the back pressure chamber. Thus, the one diaphragm valve is opened in spite of the biasing force of the corresponding coil spring (not shown in  FIGS.  4  and  5   ). 
     According to the above structure, since the one diaphragm valve (main valve body) is opened and closed by switching the opened/closed state of the one pilot hole by means of the disc-shaped member  310  (pilot valve), a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
     Structure of Fourth Embodiment 
     Hereinafter, a shower head according to a fourth embodiment of the present invention will be described with reference to  FIGS.  19  to  30   . The shower head  401  of the fourth embodiment is a shower head for which a plurality of spout modes can be switched by means of a first push button  411  and a spout mode and a water-stop mode can be switched by means of a second push button  511 . 
       FIG.  19    is a perspective view of the shower head  401  according to the fourth embodiment of the present invention,  FIG.  20    is a front view of the shower head  401  shown in  FIG.  19   ,  FIG.  21    is a longitudinal section view taken along line XXI-XXI of the shower head  401  shown in  FIG.  20   ,  FIG.  22    is a transversal section view taken along line XXII-XXII of the shower head  401  shown in  FIG.  21   , and  FIG.  23    is an exploded perspective view of the shower head  401  shown in  FIG.  19   . 
     As shown in  FIGS.  19  to  23   , the shower head  401  of the fourth embodiment also includes a storage chamber  405  (which is also called cavity) configured to store water supplied from a water supply source (not shown) through water supply members  402 ,  403 . 
     Similarly to the shower head  1  of the first embodiment, a secondary-side flow-path member  404  is provided on a spout-surface side of the shower head  401  with respect to the storage chamber  405 . The secondary-side flow-path member  404  consists of four stacked substantially discoid element parts  440 ,  447 ,  448 ,  449 . The secondary-side flow-path member  404  has three flow paths (an example of a plurality of flow paths), each of which corresponds to each of three spout modes (an example of the plurality of spout modes). 
     Four valve seats  441 ,  442 ,  443   a ,  443   b  protruded on a side of the storage chamber  405  are formed on the element part  440  facing to the storage chamber  405 . A communication hole that communicates with a corresponding flow path among the three flow paths is provided at a center of each of the valve seats  441 ,  442 ,  443   a ,  443   b  (see  FIG.  24   , too). Among the four valve seats, two valve seats  441 ,  442 , each of which has a bean shape as seen in plan view, are arranged at two of three regions which are annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. The other two valve seats  443   a ,  443   b , each of which has a circular shape as seen in plan view, are arranged at the rest one of the three regions (in order to secure a trajectory of a second shaft part  512 , which will be described below). 
     Three diaphragm valves  421  to  423 , which correspond to the above three regions, respectively, are annularly arranged (see  FIG.  23   , too). The three diaphragm valves  421  to  423  are integrally formed as one diaphragm member  420 . However, the respective diaphragm valves  421  to  423  are movable independently of each other. 
     A seal ring portion  424  is formed at a periphery of the diaphragm member  420 . The seal ring portion  424  is sandwiched between an upper edge portion  440   a  of the element part  440  and a cover member  408  in a watertight manner. A central area of the diaphragm member  420  is supported on an upper surface of the element part  440  via a spacing member  438 . 
     Coil springs  451  to  453  (an example of an elastic member) are provided between the respective diaphragm valves  421  to  423  and a lower surface of the cover member  408 , so that each of the diaphragm valves  421  to  423  is biased in a valve-closing direction by means of the corresponding coil spring  451  to  453 . 
     The three diaphragm valves  421  to  423  of the present embodiment are annularly arranged, and a pilot hole (a part of which is a back-pressure-chamber outlet hole  421   c  to  423   c  formed on a lower-surface side of the cover member  408 ) for communicating a back pressure chamber  421   b  to  423   b  of each of the three diaphragm valves  421  to  423  with a space below the element part  440 , which is a space outside the storage chamber  405 , is collectively located at a central region of the three diaphragm valves  421  to  423 , so that the pilot hole is opened and closed by a first disc-shaped member  410  and a second dsic-shaped member  510 , which serve as common pilot valves. (When the number of the plurality of diaphragm valves is two, a pilot hole for communicating a back pressure chamber of each of the two diaphragm valves with the space below the element part  440  may be collectively located at a middle region of the two diaphragm valves.) 
     The first disc-shaped member  410  is made of resin. The first disc-shaped member  410  is supported in a rotatable manner around an axis thereof, and has twelve teeth  410   t  on an outer circumference thereof (see  FIGS.  25  to  27   , too). 
     The second disc-shaped member  510  is also made of resin. The second disc-shaped member  510  is also supported in a rotatable manner around an axis thereof, and has twelve teeth  510   t  on an outer circumference thereof (see  FIGS.  28  to  30   , too). 
     In the fourth embodiment, a disc-shaped valve-seat member  610  is provided between the first disc-shaped member  410  and the second disc-shaped member  510  in a non-rotatable manner with respect to the element part  440  (or the cover member  408 ). The disc-shaped valve-seat member  610  is movable in an axial direction thereof in order to transfer a biasing force of a coil spring  435  (which will be described below) to the first disc-shaped member  410 . Thereby, the first disc-shaped member  410  and the second disc-shaped member  510  are rotatable with respect to the valve-seat member  610  independently of each other. 
       FIG.  24    is a schematic view for explaining an opened/closed state of a pilot hole. The first disc-shaped member  410  has four communication holes  410   h  (an example of the plurality of communication holes) similarly to the disc-shaped member  10  of the first embodiment. As shown in  FIG.  24    schematically, each of the four communication holes  410   h  is configured to open a corresponding pilot hole of a corresponding diaphragm valve  421  to  423  when selectively communicating with a corresponding back-pressure-chamber outlet hole  421   c  to  423   c  provided on a corresponding back pressure chamber  421   b  to  423   b  of the corresponding diaphragm valve  421  to  423 , in response to a rotational position of the first disc-shaped member  410 . More specifically, when each of the four communication holes  410   h  (and each of communication holes  510   h  which will be described below) selectively communicates with the corresponding back-pressure-chamber outlet hole  421   c  to  423   c  and a corresponding outlet hole  444  to  446  in the element part  440  provided correspondingly to the corresponding back-pressure-chamber outlet hole  421   c  to  423   c , the corresponding pilot hole of the corresponding diaphragm valve  421  to  423  is opened. The four communication holes  410   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 90 degrees. The back-pressure-chamber outlet holes  421   c  to  423   c  and the outlet holes  444  to  446  are also annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. 
     The second disc-shaped member  510  has six communication holes  510   h  similarly to the disc-shaped member  310  of the third embodiment. As shown in  FIG.  24    schematically, each of the six communication holes  510   h  is also configured to open a corresponding pilot hole of a corresponding diaphragm valve  421  to  423  when selectively communicating with a corresponding back-pressure-chamber outlet hole  421   c  to  423   c  provided on a corresponding back pressure chamber  421   b  to  423   b  of the corresponding diaphragm valve  421  to  423 , in response to a rotational position of the second disc-shaped member  510 . More specifically, when each of the six communication holes  510   h  (and each of the four communication holes  410   h  as described above) selectively communicates with the corresponding back-pressure-chamber outlet hole  421   c  to  423   c  and a corresponding outlet hole  444  to  446  in the element part  440  provided correspondingly to the corresponding back-pressure-chamber outlet hole  421   c  to  423   c , the corresponding pilot hole of the corresponding diaphragm valve  421  to  423  is opened. The six communication holes  510   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 60 degrees. 
     As shown in  FIG.  24    schematically, the disc-shaped valve-seat member  610  has three communication holes  610   h  correspondingly to the outlet holes  444  to  446 . That is to say, the communication holes  610   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. 
     Furthermore, with reference to  FIG.  24   , a disc-pushing member  430  is explained. As shown in  FIG.  24    schematically, the disc-pushing member  430  is interposed between a lower surface of the cover member  408  and an upper surface of the second disc-shaped member  510 . The disc-pushing member  430  is configured to push the second disc-shaped member  510  away from the back-pressure-chamber outlet holes  421   c  to  423   c  (toward the element part  440 ) by means of a coil spring  435  as an example of a biasing part. 
     Each of the back-pressure-chamber outlet holes  421   c  to  423   c  for the diaphragm valves  421  to  423  extends through a region around the disc-pushing member  430  to communicate with a corresponding communication hole  510   h  of the second disc-shaped member  510 . The region around the disc-pushing member  430  also communicates with the storage chamber  405  through a gap formed by a spacing member  438  or the like, and the gap is configured to function as a corresponding back-pressure-chamber inlet hole. (However, at least at the time of filing the present application, the scope of the present invention does not exclude a manner wherein each of back-pressure-chamber inlet holes is provided through a portion of the corresponding diaphragm valve  421  to  423  (see  FIG.  4   ).) 
     With reference to  FIG.  19    again, the first push button  411  is provided on a lower portion of a shower head housing  407  as an operation part configured to receive an operation force from a user. (Any other type of button or slide switch may be provided in place of the first push button  411 .) 
     With reference to  FIGS.  21  to  23   , every time the first push button  411  receives an operation force (a pushing force) from a user (every time the user gives an operation force (a pushing force) to the first push button  411 ), the first push button  411  pivots around a pivot shaft  411   s . Then, in coordination with the pivot movement, by means of abutment and slide between an abutment slide inclined portion of the first push button  411  (whose configuration is substantially the same as the abutment slide inclined portion  11   a  shown in  FIG.  2   ) and an abutment slide ring part  412   a  provided at a proximal end portion of a shaft part  412 , the shaft part  412  is configured to reciprocate in an axial direction thereof. 
     A distal end portion of the shaft part  412  is exposed to the water in the storage chamber  405  (see  FIGS.  25  to  27   , too). Thus, the shaft part  412  is made of a metal bar which is difficult to rust, such as a stainless-steel bar. In the present embodiment, the shaft part  412  slidably pierces through the element part  440  integrally fixed to the shower head housing  407 . A seal ring part  412   s  is provided for maintaining watertight performance. The shaft part  412  may be made of not only a rigid material but also a plastic material such as string or an elastic material such as rubber. 
       FIG.  25    is a schematic view for explaining a state wherein the first disc-shaped member  410  has started to be rotated,  FIG.  26    is a schematic view for explaining a state wherein the first disc-shaped member  410  is being rotated, and  FIG.  27    is a schematic view for explaining a state wherein the first disc-shaped member  410  has finished to be rotated. 
     As shown in  FIGS.  25  to  27   , a coil spring  414  is arranged around a distal end portion of the shaft part  412  located in the storage chamber  405 . A proximal end of the coil spring  414  is fixed to the element part  440 , and thus fixed to the shower head housing  407  (to the pivot shaft  411   s  of the first push button  411 ). 
     A claw member  415  is fixed to a distal end of the coil spring  414 . A stopper  413  for the claw member  415  is attached to the distal end portion of the shaft part  412 . The distal end of the coil spring  414  and the claw member  415  are movable in an axial direction by deformation of the coil spring  414  in the axial direction in a region on the side of the proximal end portion of the shaft part  412  with respect to the stopper  413 . 
     Furthermore, the distal end of the coil spring  414  and the claw member  415  are also movable in an inclined direction, which is inclined with respect to the axial direction of the coil spring  414 , by deformation of the coil spring  414  in the inclined direction. 
     A claw  415   t  is provided on a lateral surface of the claw member  415  on the side of the first disc-shaped member  410 . The claw  415   t  is configured to engage with the teeth  410   t  of the first disc-shaped member  410 . The first disc-shaped member  410  is rotated when the claw  415   t  draws one of the teeth  410   t  while the shaft part  412  reciprocates (from the state shown in  FIG.  25   , through the stage shown in  FIG.  26   , to the state sown in  FIG.  27   ). 
     In addition, a stopper claw  416  configured to prevent the first disc-shaped member  410  (teeth  410   t ) from reversely rotating is held by the element part  440  (or the cover member  408 ). 
     Furthermore, in the fourth embodiment, as shown in  FIG.  19   , the second push button  511  is also provided on a lower portion of the shower head housing  407  as an operation part configured to receive an operation force from a user. (Any other type of button or slide switch may be provided in place of the second push button  511 .) 
     With reference to  FIGS.  21  to  23    again, every time the second push button  511  receives an operation force (a pushing force) from a user (every time the user gives an operation force (a pushing force) to the second push button  511 ), the second push button  511  pivots around a pivot shaft  511   s  (which also serves as the pivot shaft  411   s  in the present embodiment). Then, in coordination with the pivot movement, by means of abutment and slide between an abutment slide inclined portion of the second push button  511  (whose configuration is substantially the same as the abutment slide inclined portion  11   a  shown in  FIG.  2   ) and an abutment slide ring part  512   a  provided at a proximal end portion of a shaft part  512 , the shaft part  512  is configured to reciprocate in an axial direction thereof. 
     In the fourth embodiment, the two shaft parts  412 ,  512  are arranged in substantially parallel to each other, at substantially the same height with respect to the upper surface of the element part  440  (see  FIG.  22   ). 
     A distal end portion of the shaft part  512  is also exposed to the water in the storage chamber  405  (see  FIGS.  28  to  30   , too). Thus, the shaft part  512  is made of a metal bar which is difficult to rust, such as a stainless-steel bar. In the present embodiment, the shaft part  512  also slidably pierces through the element part  440  integrally fixed to the shower head housing  407 . A seal ring part  512   s  is provided for maintaining watertight performance. The shaft part  512  also may be made of not only a rigid material but also a plastic material such as string or an elastic material such as rubber. 
       FIG.  28    is a schematic view for explaining a state wherein the second disc-shaped member  510  has started to be rotated,  FIG.  29    is a schematic view for explaining a state wherein the second disc-shaped member  510  is being rotated, and  FIG.  30    is a schematic view for explaining a state wherein the second disc-shaped member  510  has finished to be rotated. 
     As shown in  FIGS.  28  to  30   , a coil spring  514  is arranged around a distal end portion of the shaft part  512  located in the storage chamber  405 . A proximal end of the coil spring  514  is fixed to the element part  440 , and thus fixed to the shower head housing  407  (to the pivot shaft  511   s  of the second push button  511 ). 
     A claw member  515  is fixed to a distal end of the coil spring  514 . A stopper  513  for the claw member  515  is attached to the distal end portion of the shaft part  512 . The distal end of the coil spring  514  and the claw member  515  are movable in an axial direction by deformation of the coil spring  514  in the axial direction in a region on the side of the proximal end portion of the shaft part  512  with respect to the stopper  513 . 
     Furthermore, the distal end of the coil spring  514  and the claw member  515  are also movable in an inclined direction, which is inclined with respect to the axial direction of the coil spring  514 , by deformation of the coil spring  514  in the inclined direction. 
     A distal end region of the claw member  515  extends out upward to compensate for the offset in height between the first disc-shaped member  410  and the second disc-shaped member  510 . A claw  515   t  is provided on a lateral surface of the extended-out region of the claw member  515  on the side of the second disc-shaped member  510 . The claw  515   t  is configured to engage with the teeth  510   t  of the second disc-shaped member  510 . The second disc-shaped member  510  is rotated when the claw  515   t  draws one of the teeth  510   t  while the shaft part  512  reciprocates (from the state shown in  FIG.  28   , through the stage shown in  FIG.  29   , to the state sown in  FIG.  30   ). 
     In addition, a stopper claw  516  configured to prevent the second disc-shaped member  510  (teeth  510   t ) from reversely rotating is held by the element part  440  (or the cover member  408 ). 
     Operation of Fourth Embodiment 
     Next, an operation of the shower head  401  according to the fourth embodiment is explained. 
     With reference to  FIG.  19   , when a user pushes the first push button  411 , the pushing force (operating force) causes the abutment slide inclined portion of the first push button  411  to pivot around the pivot shaft  411   s , so that the shaft part  412  moves in a direction toward the proximal end portion thereof (the lower side in  FIG.  22   ) via the abutment slide ring part  412   a.    
     The state shown in  FIG.  25    corresponds to a state before the user pushes the first push button  411 . From this state, the shaft part  412  starts to move. When the claw  415   t  of the claw member  415  draws one of the teeth  410   t  of the first disc-shaped member  410 , the first disc-shaped member  410  is rotated, as shown in  FIG.  26   . The state shown in  FIG.  27    corresponds to a state wherein the first push button  411  has been pushed to a deepest position thereof and thus the shaft part  412  has moved to a most proximal-end-side position thereof (the lowest position in  FIG.  22   ). In the state shown in  FIG.  27   , the stopper claw  416  stops a tooth  410   t  next to that in  FIG.  25   . Accordingly, the first disc-shaped member  410  is rotated by 30 degrees every time the user pushes the first push button  411 . 
     In the state shown in  FIG.  27   , the coil spring  414  is compressed between the claw member  415  (and the stopper  413  at the distal end portion of the shaft part  412 ) and the element part  440 . From this state, when the pushing force against the first push button  411  is released, the shaft part  412  and the first push button  411  are returned back to their original positions (the state shown in  FIG.  25   ) by a resilience force of the coil spring  414 . During this step, the claw  415   t  does not engage with any tooth  410   t , and the first disc-shaped member  410  is not reversely rotated in combination with the existence of the claw stopper  416 . In addition, during the above step, the claw member  415  is movable in the inclined direction, which is inclined with respect to the axial direction of the coil spring  414 , by the deformation of the coil spring  414  in the inclined direction. Thus, it is possible to effectively avoid resistance (interference) from the first disc-shaped member  410 . In addition, when the claw member  415  is returned back to an original position thereof (the state shown in  FIG.  25   ), the claw member  415  (claw  415   t ) engages with the tooth  410   t  next to the previously drawn one, by the resilience force of the coil spring  414 . 
     As described above, the four communication holes  410   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 90 degrees, and the back-pressure-chamber outlet holes  421   c  to  423   c  and the outlet holes  444  to  446  are annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. Thus, under a condition wherein the communication holes  510   h  of the second disc-shaped member  510  are positioned correspondingly to the outlet holes  444  to  446  (and the communication holes  610   h  of the disc-shaped valve-seat member  610 ), when the first disc-shaped member  410  is rotated by 30 degrees, it is possible to sequentially switch the following three spout modes:
         (i) a first spout mode wherein the back-pressure-chamber outlet holes  421   c  and the outlet hole  444  communicate with each other while the back-pressure-chamber outlet holes  422   c ,  423   c  and the outlet holes  445 ,  446  do not communicate with each other;   (ii) a second spout mode wherein the back-pressure-chamber outlet holes  422   c  and the outlet hole  445  communicate with each other while the back-pressure-chamber outlet holes  421   c ,  423   c  and the outlet holes  444 ,  446  do not communicate with each other; and   (iii) a third spout mode wherein the back-pressure-chamber outlet holes  423   c  and the outlet hole  446  communicate with each other while the back-pressure-chamber outlet holes  421   c ,  422   c  and the outlet holes  444 ,  445  do not communicate with each other.       

     The state shown in the right side half of  FIG.  24    is an example of a state wherein a back-pressure-chamber outlet hole and the corresponding outlet hole do not communicate with each other, i.e., the corresponding pilot hole of the corresponding diaphragm valve is not opened. In the state shown in the right side half of  FIG.  24   , the back-pressure-chamber outlet holes  422   c ,  423   c  and the corresponding outlet holes  445 ,  446  are blocked by the first disc-shaped member  410 . On the other hand, through the corresponding back-pressure-chamber inlet holes, the water pressure in the storage chamber  405  and the water pressures in the back pressure chambers  423   b ,  423   c  are made equal to each other. Thus, each of the diaphragm valves  422 ,  423  is closed by a biasing force of the corresponding coil spring  452 ,  453  (not shown in  FIG.  24   ). 
     The state shown in the left side half of  FIG.  24    is an example of a state wherein a back-pressure-chamber outlet hole and the corresponding outlet hole communicate with each other, i.e., the corresponding pilot hole of the corresponding diaphragm valve is opened. In the state shown in the left side half of  FIG.  24   , the back-pressure-chamber outlet hole  421   c  and the corresponding outlet hole  444  communicate with each other through the communication hole  410   h  of the first disc-shaped member  410 . In this state, the water in the back pressure chamber  421   b  flows out through the back-pressure-chamber outlet hole  421   c  and the corresponding outlet hole  444 , so that the water pressure in the storage chamber  405  becomes greater than the water pressure in the back pressure chamber  421   b . Thus, the diaphragm valve  421  is opened in spite of the biasing force of the corresponding coil spring  451  (not shown in  FIG.  24   ). 
     Next, in the shower head  401  of the fourth embodiment, not only the plurality of spout modes can be switched by means of the first push button  411  but also a spout mode and a water-stop mode can be switched by means of the second push button  511 . 
     With reference to  FIG.  19    again, when a user pushes the second push button  511 , the pushing force (operating force) causes the abutment slide inclined portion of the second push button  511  to pivot around the pivot shaft  511   s , so that the shaft part  512  moves in a direction toward the proximal end portion thereof (the lower side in  FIG.  22   ) via the abutment slide ring part  512   a.    
     The state shown in  FIG.  28    corresponds to a state before the user pushes the second push button  511 . From this state, the shaft part  512  starts to move. When the claw  515   t  of the claw member  515  draws one of the teeth  510   t  of the second disc-shaped member  510 , the second disc-shaped member  510  is rotated, as shown in  FIG.  29   . The state shown in  FIG.  30    corresponds to a state wherein the second push button  511  has been pushed to a deepest position thereof and thus the shaft part  512  has moved to a most proximal-end-side position thereof (the lowest position in  FIG.  22   ). In the state shown in  FIG.  30   , the stopper claw  516  stops a tooth  510   t  next to that in  FIG.  28   . Accordingly, the second disc-shaped member  510  is rotated by 30 degrees every time the user pushes the second push button  511 . 
     In the state shown in  FIG.  30   , the coil spring  514  is compressed between the claw member  515  (and the stopper  513  at the distal end portion of the shaft part  512 ) and the element part  440 . From this state, when the pushing force against the second push button  511  is released, the shaft part  512  and the second push button  511  are returned back to their original positions (the state shown in  FIG.  28   ) by a resilience force of the coil spring  514 . During this step, the claw  515   t  does not engage with any tooth  510   t , and the second disc-shaped member  510  is not reversely rotated in combination with the existence of the claw stopper  516 . In addition, during the above step, the claw member  515  is movable in the inclined direction, which is inclined with respect to the axial direction of the coil spring  514 , by the deformation of the coil spring  514  in the inclined direction. Thus, it is possible to effectively avoid resistance (interference) from the second disc-shaped member  510 . In addition, when the claw member  515  is returned back to an original position thereof (the state shown in  FIG.  28   ), the claw member  515  (claw  515   t ) engages with the tooth  510   t  next to the previously drawn one, by the resilience force of the coil spring  514 . 
     As described above, the six communication holes  510   h  are annularly arranged at even intervals in a circumferential direction, i.e., every 60 degrees, and the back-pressure-chamber outlet holes  421   c  to  423   c  and the outlet holes  444  to  446  are annularly arranged at even intervals in a circumferential direction, i.e., every 120 degrees. Thus, when the second disc-shaped member  510  is rotated by 30 degrees, it is possible to sequentially switch the spout mode, in which the back-pressure-chamber outlet holes and the outlet holes communicate with each other through the communication holes  510   h  of the second disc-shaped member  510 , and the water-stop mode, in which the back-pressure-chamber outlet holes and the outlet holes do not communicate with each other (the back-pressure-chamber outlet holes and the outlet holes are blocked by the second disc-shaped member  510 ). 
     Effects of Fourth Embodiment 
     As described above, according to the shower head  401  of the fourth embodiment, since the communicated/blocked state between each of the three flow paths and the storage chamber  405  is controlled by each of the three diaphragm valves  421  to  423 , a remarkable and stable reduction of an operation force for the switching operation is achieved for a long time without using grease. 
     In particular, according to the shower head  401  of the fourth embodiment, the switching operation between the plurality of spout modes by means of the first push button  411  and the switching operation between the spout mode and the water-stop mode by means of the second push button  511  are independent of each other, which contributes to good operability, 
     In addition, according to the shower head  401  of the fourth embodiment, the pilot hole for communicating the back pressure chamber  421   b  to  423   b  of each of the annularly-arranged three diaphragm valves  421  to  423  with the space outside the storage chamber  405  is collectively located at the central region of the three diaphragm valves  421  to  423  so that the pilot hole is opened and closed by the common first and second disc-shaped members  410 ,  510  (pilot valves). Thus, the shower head  401  is made to be compact. In addition, a moving range (moving distance) of the first disc-shaped member  410  (pilot valve) and a moving range (moving distance) of the second disc-shaped member  510  (pilot valve) are sufficiently small, which contributes to a further reduction of the operating force. 
     In addition, according to the shower head  401  of the fourth embodiment, the first disc-shaped member  410  is supported in a rotatable manner around the axis thereof and has the teeth  410   t  on the outer circumference thereof. Thus, it is possible to easily drive the first disc-shaped member  410  in rotation by using the teeth  410   t.    
     In addition, according to the shower head  401  of the fourth embodiment, the first disc-shaped member  410  is made of resin. Thus, it is possible to easily achieve high smoothness, which can inhibit sliding resistance (sliding friction). In addition, it is unnecessary to separately provide a seal part. 
     In addition, according to the shower head  401  of the fourth embodiment, the first disc-shaped member  410  has the four communication holes  410   h , and each of the four communication holes  410   h  is configured to open the corresponding pilot hole of the corresponding diaphragm valve  421  to  423  when selectively communicating with the corresponding back-pressure-chamber outlet hole  421   c  to  423   c  provided on the corresponding back pressure chamber  421   b  to  423   b  of the corresponding diaphragm valve  421  to  423 , in response to a rotational position of the first disc-shaped member  410 . Thus, the shower head  401  is made to be more compact. In addition, a rotation angle (moving distance) of the first disc-shaped member  410  (pilot valve) is sufficiently small (no more than 30 degrees), which contributes to a further reduction of the operating force. 
     Substantially similarly, according to the shower head  401  of the fourth embodiment, the second disc-shaped member  510  is also supported in a rotatable manner around the axis thereof and has the teeth  510   t  on the outer circumference thereof. Thus, it is also possible to easily drive the second disc-shaped member  510  in rotation by using the teeth  510   t.    
     In addition, according to the shower head  401  of the fourth embodiment, the second disc-shaped member  510  is also made of resin. Thus, it is possible to easily achieve high smoothness, which can inhibit sliding resistance (sliding friction). In addition, it is unnecessary to separately provide a seal part. 
     In addition, according to the shower head  401  of the fourth embodiment, the second disc-shaped member  510  has the six communication holes  510   h , and each of the six communication holes  510   h  is configured to open the corresponding pilot hole of the corresponding diaphragm valve  421  to  423  when selectively communicating with the corresponding back-pressure-chamber outlet hole  421   c  to  423   c  provided on the corresponding back pressure chamber  421   b  to  423   b  of the corresponding diaphragm valve  421  to  423 , in response to a rotational position of the second disc-shaped member  510 . Thus, the shower head  401  is made to be more compact. In addition, a rotation angle (moving distance) of the second disc-shaped member  510  (pilot valve) is sufficiently small (no more than 30 degrees), which contributes to a further reduction of the operating force. 
     In addition, according to the shower head  401  of the fourth embodiment, the disc-pushing member  430  is interposed between the corresponding back-pressure-chamber outlet hole  421   c  to  423   c  and the second disc-shaped member  510 , and the disc-pushing member  430  is configured to push the second disc-shaped member  510 , the valve-seat member  610  and the first disc-shaped member  410  away from the corresponding back-pressure-chamber outlet hole  421   c  to  423   c  by means of the coil spring  435 . Thus, it is unnecessary to provide a seal part between the first disc-shaped member  410  and the element part  440  (a member located away from the back-pressure-chamber outlet holes  421   c  to  423   c  with respect to the first disc-shaped member  410 ). 
     In addition, according to the shower head  401  of the fourth embodiment, the gap formed by the spacing member  438  or the like, which communicates with the region around the disc-pushing member  430 , is configured to function as a corresponding back-pressure-chamber inlet hole. It is easy to form the gap with high precision, and thus it is possible to effectively inhibit variation in performance among the three back-pressure-chamber inlet holes (the three gaps) for the three diaphragm valves  421  to  423 . 
     In addition, according to the shower head  401  of the fourth embodiment, by using a driving mechanism including: the first push button  411  configured to receive an operation force from a user; the shaft part  412  configured to reciprocate in the axial direction thereof every time the first push button  411  receives the operation force; and the claw member  415  attached to the distal end portion of the shaft part  412  and having the claw  415   t  configured to engage with the teeth  410   t  of the first disc-shaped member  410 , the first disc-shaped member  410  is rotated when the claw  415   t  draws one of the teeth  410   t  while the shaft part  412  reciprocates. Since the force for driving the first disc-shaped member  410  in rotation is applied in a direction in which the claw  415   t  draws one of the teeth  410   t , it is possible to prevent (avoid) buckling deformation of the shaft part  412 . Thus, rigidity required for the shaft part  412  can be reduced. As a result, it is possible to make the shaft part  412  of not only a rigid material but also a plastic material such as string or an elastic material such as rubber. 
     In particular, according to the shower head  401  of the fourth embodiment, the proximal end portion of the shaft part  412  is operably connected to the first push button part  411 , the coil spring  414  is arranged around the distal end portion of the shaft part  412 , the proximal end of the coil spring  414  is fixed to the element part  440 , the distal end of the coil spring  414  is fixed to the claw member  415 , and the stopper  413  for the claw member  415  is attached to the distal end portion of the shaft part  412 . Thus, the claw member  415  is movable relative to the shaft part  412  by deformation of the coil spring  414  (both in the axial direction and in the inclined direction). Thus, after the claw member  415  has drawn one tooth  410   t , when the claw member  415  is returned to the original position thereof (the state shown in  FIG.  25   ) to engage with the next tooth  410   t , it is possible to effectively avoid resistance (interference) from the first disc-shaped member  410 . 
     Substantially similarly, according to the shower head  401  of the fourth embodiment, by using a driving mechanism including: the second push button  511  configured to receive an operation force from a user; the shaft part  512  configured to reciprocate in the axial direction thereof every time the second push button  511  receives the operation force; and the claw member  515  attached to the distal end portion of the shaft part  512  and having the claw  515   t  configured to engage with the teeth  510   t  of the second disc-shaped member  510 , the second disc-shaped member  510  is rotated when the claw  515   t  draws one of the teeth  510   t  while the shaft part  512  reciprocates. Since the force for driving the second disc-shaped member  510  in rotation is applied in a direction in which the claw  515   t  draws one of the teeth  510   t , it is possible to prevent (avoid) buckling deformation of the shaft part  512 . Thus, rigidity required for the shaft part  512  can be reduced. As a result, it is possible to make the shaft part  512  of not only a rigid material but also a plastic material such as string or an elastic material such as rubber. 
     In particular, according to the shower head  401  of the fourth embodiment, the proximal end portion of the shaft part  512  is operably connected to the second push button part  511 , the coil spring  514  is arranged around the distal end portion of the shaft part  512 , the proximal end of the coil spring  514  is fixed to the element part  440 , the distal end of the coil spring  514  is fixed to the claw member  515 , and the stopper  513  for the claw member  515  is attached to the distal end portion of the shaft part  512 . Thus, the claw member  515  is movable relative to the shaft part  512  by deformation of the coil spring  514  (both in the axial direction and in the inclined direction). Thus, after the claw member  515  has drawn one tooth  510   t , when the claw member  515  is returned to the original position thereof (the state shown in  FIG.  28   ) to engage with the next tooth  510   t , it is possible to effectively avoid resistance (interference) from the second disc-shaped member  510 . 
     In addition, according to the shower head  401  of the fourth embodiment, the three diaphragm valves  421  to  423  are integrally formed as the one diaphragm member  420 , and the seal ring portion  424  is provided at the periphery of the diaphragm member  420 . Thus, it is unnecessary to separately provide a seal ring part. 
     In addition, according to the shower head  401  of the fourth embodiment, each of the three diaphragm valves  421  to  423  is biased in a valve-closing direction by means of the corresponding coil spring  451  to  453 . Thus, the movement for opening and closing each of the three diaphragm valves  421  to  423  is stabilized. 
     [Complement Regarding Flow Paths] 
     In the shower head  401  of the fourth embodiment as well, the opened/closed state of each of the three diaphragm valves  421  to  423  corresponds to the communicated/blocked state of each of the three flow paths in the secondary-side flow-path member  404  on a one-to-one basis, and just one diaphragm valve is opened at a time in response to a rotational position of the first disc-shaped member  410 , so that just one flow path is communicated at the time. However, the present invention is not limited to this matter, 
     For example, by changing an arrangement pattern of the communication holes  410   h  of the first disc-shaped member  410 , a plurality of diaphragm valves may be opened at the same time in response to a rotational position of the first disc-shaped member  410 , so that a plurality of flow paths may be communicated at the same time to achieve a composite-type spout. 
     Alternatively, for example, by changing an arrangement pattern of the flow paths in the secondary-side flow-path member  404 , a plurality of flow paths may be communicated at the same time to achieve a composite-type spout when a specific diaphragm valve is opened.