Patent Publication Number: US-2023133598-A1

Title: Electromagnetic valve manifold

Description:
BACKGROUND 
     1. Field 
     The present disclosure relates to an electromagnetic valve manifold. 
     2. Description of Related Art 
     An electromagnetic valve manifold includes an electromagnetic valve and a manifold base, on which the electromagnetic valve is mounted. The manifold base includes a supply passage, an output passage, and a discharge passage. The electromagnetic valve includes a casing and a valve member. The casing includes a valve hole, a supply port, an output port, and a discharge port. The supply port, the output port, and the discharge port are each connected to the valve hole. The supply port is connected to the supply passage of the manifold base. The output port is connected to the output passage of the manifold base. The discharge port is connected to the discharge passage of the manifold base. The valve member is movably accommodated in the valve hole. The valve member moves within the valve hole, so as to switch connection state among the ports. The fluid flowing through the output passage drives a fluid pressure device connected to the output passage. 
     For example, Japanese Laid-Open Utility Model Publication No. 61-197364 discloses an electromagnetic valve manifold that includes a stopper valve arranged between a manifold base and an electromagnetic valve. The stopper valve includes a spool that is switched between a first switching position and a second switching position. For example, when switched to the first switching position, the spool allows for connection between the supply port and the supply passage, connection between the output port and the output passage, and connection between the discharge port and the discharge passage. In contrast, when switched to the second switching position, the spool blocks the connection between the supply port and the supply passage and the connection between the discharge port and the discharge passage. When in the second switching position, the spool allows for connection between the output port and the output passage. Thus, when in the second switching position, the spool only allows for the connection between the output port and the output passage. When in the second switching position, the spool blocks the connection between the discharge port and the discharge passage. Thus, the fluid in the output passage will not be discharged to the outside from the discharge passage through the output port and the discharge port. As a result, the pressure of the fluid between the output passage and the fluid pressure device is maintained, and operation of the fluid pressure device is stopped. Such an electromagnetic valve manifold switches the spool to the second switching position to keep the fluid pressure device deactivated, for example, when an operator performs maintenance. This allows the operator to perform maintenance safely. 
     In the above-described publication, for example, a pressure loss of the fluid may occur since the fluid flows through the stopper valve. Thus, the flow rate of the fluid supplied to and discharged from the fluid pressure device may be insufficient. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     In one general aspect, an electromagnetic valve manifold is provided that includes an electromagnetic valve and a manifold base on which the electromagnetic valve is mounted. The manifold base includes a supply passage, an output passage, and a discharge passage. The electromagnetic valve includes a casing including a valve hole, a valve member that is movably accommodated in the valve hole, and a supply port, an output port, and a discharge port that are formed in the casing and respectively connected to the valve hole. The supply port is connected to the supply passage. The output port is connected to the output passage. The discharge port is connected to the discharge passage. The output passage is configured such that a fluid flowing through the output passage drives a fluid pressure device connected to the output passage. The electromagnetic valve includes a manual shaft. The manual shaft is configured to be manually operated to be switched between a first switching position, in which the manual shaft allows the valve member to move relative to the valve hole, and a second switching position, in which the manual shaft restricts movement of the valve member relative to the valve hole, thereby maintaining a pressure of a fluid between the output passage and the fluid pressure device. The manual shaft includes a projection that is projected into and retracted from the valve hole. The valve member includes at least one recess in an outer surface of the valve member. The manual shaft is configured such that, in a state in which the manual shaft is located in the second switching position, the projection is projected into the valve hole and engaged with the recess, so as to restrict movement of the valve member relative to the valve hole. 
     Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional view of an electromagnetic valve manifold according to one embodiment. 
         FIG.  2    is an enlarged partial cross-sectional view of the electromagnetic valve manifold shown in  FIG.  1   . 
         FIG.  3    is a cross-sectional view of the electromagnetic valve manifold of  FIG.  1   , showing flow of fluid when a spool valve is in a second position. 
         FIG.  4    is an exploded perspective view of an operation block of the electromagnetic valve manifold shown in  FIG.  1   . 
         FIG.  5    is a cross-sectional view of the electromagnetic valve manifold of  FIG.  1   , showing flow of fluid when a manual shaft is in a second switching position. 
         FIG.  6    is a perspective view, with a part cut away, of an operating member in the electromagnetic valve manifold of  FIG.  1   , illustrating a state in which the manual shaft is in a first switching position. 
         FIG.  7    is a perspective view, with a part cut away, of the operating member in the electromagnetic valve manifold of  FIG.  1   , illustrating a state in which the manual shaft is in a second switching position. 
         FIG.  8    is a cross-sectional view showing a state in which a padlock is attached to the operating member in the electromagnetic valve manifold of  FIG.  1   . 
     
    
    
     Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience. 
     DETAILED DESCRIPTION 
     This description provides a comprehensive understanding of the methods, apparatuses, and/or systems described. Modifications and equivalents of the methods, apparatuses, and/or systems described are apparent to one of ordinary skill in the art. Sequences of operations are exemplary, and may be changed as apparent to one of ordinary skill in the art, with the exception of operations necessarily occurring in a certain order. Descriptions of functions and constructions that are well known to one of ordinary skill in the art may be omitted. 
     Exemplary embodiments may have different forms, and are not limited to the examples described. However, the examples described are thorough and complete, and convey the full scope of the disclosure to one of ordinary skill in the art. 
     In this specification, “at least one of A and B” should be understood to mean “only A, only B, or both A and B.” 
     An electromagnetic valve manifold  10  according to one embodiment will now be described with reference to  FIGS.  1  to  8   . 
     &lt;Overall Configuration of Electromagnetic Valve Manifold  10 &gt; 
     As shown in  FIG.  1   , the electromagnetic valve manifold  10  includes at least one electromagnetic valve  11  and a rectangular block-shaped manifold base  50 . The electromagnetic valve  11  is mounted on a mounting surface  50   a  of the manifold base  50 . The electromagnetic valve  11  is thus mounted on the manifold base  50 . The electromagnetic valve  11  and the manifold base  50  form the electromagnetic valve manifold  10 . 
     &lt;Configuration of Electromagnetic Valve  11 &gt; 
     The electromagnetic valve  11  includes an elongated rectangular block-shaped casing C 1 . The casing C 1  includes a valve casing  12  and an operation block  14 . The valve casing  12  includes an elongated rectangular block-shaped casing body  13 , a first coupling block  15 , and a second coupling block  16 . 
     The casing body  13  is made of, for example, an aluminum alloy. The operation block  14 , the first coupling block  15 , and the second coupling block  16  are made of, for example, plastic. The casing body  13  includes a body facing surface  13   a , which faces the manifold base  50 . 
     The operation block  14  is coupled to a first end face in the longitudinal direction of the casing body  13 . The operation block  14  is coupled to the first end face in the longitudinal direction of the casing body  13  with a traverse direction of the operation block  14  agreeing with the longitudinal direction of the casing body  13 . The first coupling block  15  is coupled to a first end face in the traverse direction of the operation block  14 . The first end face in the traverse direction of the operation block  14  is on a side of the operation block  14  that is opposite to the casing body  13 . The second coupling block  16  is coupled to a second end face in the longitudinal direction of the casing body  13 . 
     &lt;Valve Hole  17 &gt; 
     As shown in  FIG.  2   , the casing C 1 , specifically, the valve casing  12 , includes a circular valve hole  17 . The valve hole  17  includes a first valve hole  18  and a second valve hole  19 . The first valve hole  18  is formed in the casing body  13 . The first valve hole  18  extends in the longitudinal direction of the casing body  13 . A first end of the first valve hole  18  opens in the first end face in the longitudinal direction of the casing body  13 . A second end of the first valve hole  18  opens in the second end face in the longitudinal direction of the casing body  13 . The first valve hole  18  thus extends through the casing body  13  in the longitudinal direction. 
     The second valve hole  19  is formed in the operation block  14 . The second valve hole  19  extends through the operation block  14  in the traverse direction of the operation block  14 . The second valve hole  19  is connected to first valve hole  18 . The axis of the first valve hole  18  and the axis of the second valve hole  19  agree with each other. The first valve hole  18  and the second valve hole  19  extend in the longitudinal direction of the casing C 1 . The valve hole  17  thus extends in the longitudinal direction of the casing C 1 . An axis L 1  of the valve hole  17  extends in the longitudinal direction of the casing C 1 . A first end of the valve hole  17  opens in the first end face in the traverse direction of the operation block  14 . A second end of the valve hole  17  opens in the second end face in the longitudinal direction of the casing body  13 . The valve hole  17  thus extends through the casing body  13  and the operation block  14 . The valve hole  17  accommodates a spool valve  30 , which is a valve member. The spool valve  30  is allowed to reciprocate within the valve hole  17 . The spool valve  30  is thus movably accommodated in the valve hole  17 . 
     The casing body  13  includes a supply port P 1 , a first output port A 1 , a second output port A 2 , a first discharge port R 1 , and a second discharge port R 2 , which are each connected to the first valve hole  18 . The supply port P 1 , the first output port A 1 , the second output port A 2 , the first discharge port R 1 , and the second discharge port R 2  are each connected to the valve hole  17 . 
     Thus, the electromagnetic valve  11  includes the supply port P 1 , the first output port A 1 , the second output port A 2 , the first discharge port R 1 , and the second discharge port R 2 , which are formed in the casing C 1  and connected to the valve hole  17 . The first output port A 1  and the second output port A 2  are formed in the casing C 1 . Accordingly, the output ports include the first output port A 1  and the second output port A 2 . The first discharge port R 1  and the second discharge port R 2  are formed in the casing C 1 . The electromagnetic valve  11  of the present embodiment is a five-port electromagnetic valve. 
     The first discharge port R 1 , the first output port A 1 , the supply port P 1 , the second output port A 2 , and the second discharge port R 2  are arranged in that order from a first end to a second end in the longitudinal direction of the casing body  13 . First ends of the supply port P 1 , the first output port A 1 , the second output port A 2 , the first discharge port R 1 , and the second discharge port R 2  are each connected to the valve hole  17 . Second ends of the supply port P 1 , the first output port A 1 , the second output port A 2 , the first discharge port R 1 , and the second discharge port R 2  each open in the body facing surface  13   a  of the casing body  13 . 
     &lt;First Piston  21  and Second Piston  22 &gt; 
     The electromagnetic valve  11  includes a first piston  21  and a second piston  22 . The first piston  21  has the shape of a disc. The first piston  21  is coupled to a first end of the spool valve  30 . The first piston  21  moves integrally with the spool valve  30 . The second piston  22  has the shape of a disc. The second piston  22  is coupled to a second end of the spool valve  30 . The second piston  22  moves integrally with the spool valve  30 . 
     &lt;First Pilot Pressure Chamber  23  and Second Pilot Pressure Chamber  24 &gt; 
     The first coupling block  15  includes a first piston accommodating recess  15   a , which is a circular hole. The first piston accommodating recess  15   a  accommodates the first piston  21 , while allowing the first piston  21  to reciprocate. The first piston accommodating recess  15   a  and the first piston  21  define a first pilot pressure chamber  23 . Pilot fluid is supplied to and discharged from the first pilot pressure chamber  23 . 
     The second coupling block  16  includes a second piston accommodating recess  16   a , which is a circular hole. The second piston accommodating recess  16   a  accommodates the second piston  22 , while allowing the second piston  22  to reciprocate. The second piston accommodating recess  16   a  and the second piston  22  define a second pilot pressure chamber  24 . Pilot fluid is supplied to and discharged from the second pilot pressure chamber  24 . 
     As shown in  FIG.  1   , the electromagnetic valve  11  includes a first pilot valve V 1  and a second pilot valve V 2 . The electromagnetic valve  11  is therefore a double-solenoid electromagnetic pilot valve. Voltage are applied to the first pilot valve V 1  and the second pilot valve V 2 , for example, by an external controller (not shown) such as a programmable logic controller (PLC). 
     &lt;First Position and Second Position&gt; 
     The spool valve  30  is switchable between a first position and a second position. For example, there may be a case in which voltage is applied to the first pilot valve V 1 , and voltage is not applied to the second pilot valve V 2 . In this case, the first pilot valve V 1  supplies compressed fluid, which is pilot fluid, from a fluid supply source (not shown) to the first pilot pressure chamber  23 . The second pilot valve V 2  discharges the pilot fluid in the second pilot pressure chamber  24  to the atmosphere. Accordingly, the spool valve  30  moves toward the second piston accommodating recess  16   a . As a result, the spool valve  30  is switched to the first position, in which the supply port P 1  is connected to the first output port A 1 , and the second output port A 2  is connected to the second discharge port R 2 . Also, when the spool valve  30  is switched to the first position, the supply port P 1  and the second output port A 2  are disconnected from each other, and the first output port A 1  and the first discharge port R 1  are disconnected from each other. In  FIG.  1   , the parts through which the fluid flows are depicted with stippling. 
     There may be a case in which voltage is not applied to the first pilot valve V 1 , and voltage is applied to the second pilot valve V 2  as shown in  FIG.  3   . In this case, the second pilot valve V 2  supplies compressed fluid, which is pilot fluid, from the fluid supply source to the second pilot pressure chamber  24 . The first pilot valve V 1  discharges the pilot fluid in the first pilot pressure chamber  23  to the atmosphere. Accordingly, the spool valve  30  moves toward the first piston accommodating recess  15   a . As a result, the spool valve  30  is switched to the second position, in which the supply port P 1  is connected to the second output port A 2 , and the first output port A 1  is connected to the first discharge port R 1 . Also, when the spool valve  30  is switched to the second position, the supply port P 1  and the first output port A 1  are disconnected from each other, and the second output port A 2  and the second discharge port R 2  are disconnected from each other. 
     Thus, the first pilot valve V 1  supplies pilot fluid to and discharges pilot fluid from the first pilot pressure chamber  23 , and the second pilot valve V 2  supplies pilot fluid to and discharges pilot fluid from the second pilot pressure chamber  24 , so that the spool valve  30  reciprocates in the valve hole  17  between the first position and the second position. The connection state among the ports is switched as the spool valve  30  is switched between the first position and the second position. 
     &lt;Configuration of Manifold Base  50 &gt; 
     As shown in  FIGS.  1  and  2   , the manifold base  50  includes a supply passage  51 , a first output passage  52 , a second output passage  53 , a first discharge passage  54 , and a second discharge passage  55 . The first output passage  52  and the second output passage  53  are formed in the manifold base  50 . Accordingly, the output passages include the first output passage  52  and the second output passage  53 . The first discharge passage  54  and the second discharge passage  55  are formed in the manifold base  50 . The supply passage  51 , the first output passage  52 , the second output passage  53 , the first discharge passage  54 , and the second discharge passage  55  each include a first end that opens in the mounting surface  50   a . The supply port P 1  is connected to the supply passage  51 . The first output port A 1  is connected to the first output passage  52 . The second output port A 2  is connected to the second output passage  53 . Accordingly, the output ports include the first output port A 1  and the second output port A 2 . The first discharge port R 1  is connected to the first discharge passage  54 . The second discharge port R 2  is connected to the second discharge passage  55 . 
     A second end of the supply passage  51  is connected to the fluid supply source (not shown) via piping and the like. A second end of the first output passage  52  is connected to an actuator X 1 , which is a fluid pressure device, through a first pipe T 1 . The first pipe T 1  is connected to the manifold base  50  through a first coupling T 10 . A second end of the second output passage  53  is connected to the actuator X 1  through a second pipe T 2 . The second pipe T 2  is connected to the manifold base  50  through a second coupling T 20 . The second end of the first output passage  52  and the second end of the second output passage  53  are open in a wall surface  50   b  of the manifold base  50 . A second end of the first discharge passage  54  and a second end of the second discharge passage  55  are open to the atmosphere. 
     The actuator X 1  includes a cylinder tube X 2 . The cylinder tube X 2  accommodates a piston X 3 , while allowing the piston X 3  to reciprocate. A piston rod X 4  is coupled to the piston X 3 . The piston rod X 4  is selectively protruded from and retracted into the cylinder tube X 2 . The interior of the cylinder tube X 2  is divided into a first pressure chamber X 5  and a second pressure chamber X 6  by the piston X 3 . The first output passage  52  is connected to the first pressure chamber X 5  through the first pipe T 1 . The second output passage  53  is connected to the second pressure chamber X 6  through the second pipe T 2 . 
     &lt;First Recess  31  and Second Recess  32 &gt; 
     As shown in  FIG.  2   , the spool valve  30  includes a columnar protrusion  30   a  at a first end. The protrusion  30   a  includes a first recess  31  and a second recess  32  in the outer circumferential surface. Thus, the spool valve  30  has two recesses in the outer circumferential surface of the spool valve  30 . Each of the first recess  31  and the second recess  32  extends over the entire circumference of the outer circumferential surface of the protrusion  30   a . The first recess  31  and the second recess  32  are arranged in that order from the first end to the second end of the spool valve  30 . 
     &lt;Configuration of Shaft Hole  33 &gt; 
     The operation block  14  includes a circular shaft hole  33 . The shaft hole  33  extends in the longitudinal direction of the operation block  14 . A first end of the shaft hole  33  opens in a first end face  140 , which is an end face in the longitudinal direction of the operation block  14 . The shaft hole  33  thus includes an opening  33   a , which opens in an end face of the casing C 1 . 
     &lt;Insertion Hole  14   h&gt;   
     The operation block  14  includes an insertion hole  14   h , which connects the valve hole  17  and the shaft hole  33  to each other. The casing C 1  thus includes the insertion hole  14   h . When the spool valve  30  is located in the first position, the insertion hole  14   h  is aligned with the first recess  31  in the longitudinal direction of the operation block  14 . When the spool valve  30  is located in the second position, the insertion hole  14   h  is aligned with the second recess  32  in the longitudinal direction of the operation block  14  as shown in  FIG.  3   . 
     &lt;Configuration of Manual Shaft  40 &gt; 
     As shown in  FIG.  2   , the electromagnetic valve  11  includes a manual shaft  40 , which is movably received in the shaft hole  33 . The casing C 1  thus includes the shaft hole  33 , which movably receives the manual shaft  40 . The manual shaft  40  is columnar. 
     The manual shaft  40  includes a shaft body  41  and a stopper member  42 . The shaft body  41  has a columnar shape. The shaft body  41  includes an anchor portion  43 . The anchor portion  43  protrude from a first end of the shaft body  41 , which is close to the insertion hole  14   h.    
     As shown in  FIG.  4   , the stopper member  42  includes a substantially columnar holding portion  44  and a flat plate shaped projection  45 . The holding portion  44  includes a slit  44   a . The slit  44   a  is formed so as to extend from the center of the holding portion  44  to the outer circumferential surface and open in the outer circumferential surface in a plan view in the axial direction of the holding portion  44 . The anchor portion  43  is slid into the slit  44   a  through the opening of the slit  44   a  so that the holding portion  44  of the stopper member  42  is held by the anchor portion  43 . The stopper member  42  is thus attached to the first end of the shaft body  41 . The stopper member  42  is movable integrally with the shaft body  41  within the shaft hole  33 . The shaft body  41  is rotatable about the axis of the shaft body  41  relative to the stopper member  42 . 
     The projection  45  projects from an end of the holding portion  44  that is close to the insertion hole  14   h . The projection  45  can be inserted into the insertion hole  14   h . When the shaft body  41  is pushed toward the insertion hole  14   h , the projection  45  protrudes into the valve hole  17  through the insertion hole  14   h . If the projection  45  projects into the valve hole  17  when the spool valve  30  is located in the first position, the projection  45  is engaged with the first recess  31  as shown in  FIG.  5   . If the projection  45  projects into the valve hole  17  when the spool valve  30  is located in the second position, the projection  45  is engaged with the second recess  32 . 
     &lt;First Switching Position and Second Switching Position&gt; 
     The manual shaft  40  is manually operated through the opening  33   a . The manual shaft  40  is switchable between the first switching position and the second switching position through manual operation. 
     When the manual shaft  40  is located in the first switching position, the projection  45  is retracted into the shaft hole  33  as shown in  FIGS.  1  and  3   . Accordingly, when in the first switching position, the manual shaft  40  allows the spool valve  30  to move relative to the valve hole  17 . 
     When the manual shaft  40  is located in the second switching position, the projection  45  projects into the valve hole  17  through the insertion hole  14   h  as shown in  FIG.  5   . The insertion hole  14   h  guides the projection  45  when the manual shaft  40  moves between the first switching position and the second switching position. When the manual shaft  40  is located in the second switching position, and the spool valve  30  is located in the first position, the projection  45  of the stopper member  42  protrudes into the valve hole  17  via the insertion hole  14   h  so as to be engaged with the first recess  31 . The manual shaft  40  thus restricts movement of the spool valve  30  relative to the valve hole  17 . The spool valve  30  is therefore held in the first position. 
     When the manual shaft  40  is located in the second switching position, and the spool valve  30  is located in the second position, the projection  45  of the stopper member  42  protrudes into the valve hole  17  via the insertion hole  14   h  so as to be engaged with the second recess  32 . The manual shaft  40  thus restricts movement of the spool valve  30  relative to the valve hole  17 . The spool valve  30  is therefore held in the second position. 
     As such, if the manual shaft  40  is located in the second switching position when the spool valve  30  is located in the first position, the projection  45  protrudes into the valve hole  17  and is engaged with one of the first recess  31  and the second recess  32 , so as to restrict movement of the spool valve  30  relative to the valve hole  17 . If the manual shaft  40  is located in the second switching position when the spool valve  30  is located in the second position, the projection  45  protrudes into the valve hole  17  and is engaged with the other one of the first recess  31  and the second recess  32 , so as to restrict movement of the spool valve  30  relative to the valve hole  17 . 
     &lt;Configuration of Fixing Pin  46  and Urging Spring  47 &gt; 
     As shown in  FIGS.  4 ,  6 , and  7   , the electromagnetic valve  11  includes a fixing pin  46 , which is an insertion member, and an urging spring  47 , which is an urging member. The fixing pin  46  has the shape of an elongated thin column. The fixing pin  46  protrudes into the shaft hole  33 . 
     The urging spring  47  is accommodated in the shaft hole  33 . The urging spring  47  is located between the operation block  14  and the manual shaft  40 . A first end of the urging spring  47  is supported by the operation block  14 . A second end of the urging spring  47  is supported by the shaft body  41 . The urging spring  47  applies to the manual shaft  40  an urging force that urges the manual shaft  40  toward the first switching position. 
     &lt;Configuration of Unlocking Slot  48  and Locking Slot  49 &gt; 
     The shaft body  41  includes an unlocking slot  48  and a locking slot  49 . The manual shaft  40  thus includes the unlocking slot  48  and the locking slot  49 . The unlocking slot  48  opens in the outer circumferential surface of the shaft body  41 . The unlocking slot  48  extends in the axial direction of the shaft body  41 . The circumferential width of the unlocking slot  48  is slightly larger than the outer diameter of the fixing pin  46 . 
     The manual shaft  40  has an axis L 2 . 
     In a state in which the fixing pin  46  is in the unlocking slot  48 , the unlocking slot  48  allows the shaft body  41  to move in the axis L 2  relative to the shaft hole  33  and restricts rotation of the manual shaft  40  in the shaft hole  33  about the axis L 2 . 
     The locking slot  49  opens in the outer circumferential surface of the shaft body  41 . The locking slot  49  extends in the circumferential direction of the shaft body  41 . The locking slot  49  is continuous with one end of the unlocking slot  48 . When the manual shaft  40  is moved from the first switching position to the second switching position against the urging force of the urging spring  47  with the fixing pin  46  in the unlocking slot  48 , the locking slot  49  is located at the same position as the fixing pin  46  in the axial direction of the manual shaft  40 . In this state, the locking slot  49  and the fixing pin  46  cooperate to allow the manual shaft  40  to rotate about the axis L 2 . That is, the fixing pin  46  is moved into the locking slot  49  so that the manual shaft  40  is permitted to rotate about the axis L 2  in the shaft hole  33 . When the fixing pin  46  is moved into the locking slot  49 , the manual shaft  40  is prevented from being moved toward the first switching position by the urging force of the urging spring  47 . In the present embodiment, the length in the circumferential direction of the locking slot  49  is set to allow the manual shaft  40  to rotate about the axis L 2  by 90°. 
     &lt;Through-Holes  14   a&gt;   
     As shown in  FIGS.  2  and  4   , the operation block  14  includes two through-holes  14   a . The casing C 1  thus includes the two through-holes  14   a . As shown in  FIG.  5   , the two through-holes  14   a  are closer to the opening  33   a  in the axial direction of the manual shaft  40  than the manual shaft  40  located in the second switching position. The two through-holes  14   a  are located on opposite sides of the axis of the shaft hole  33 . The two through-hole  14   a  have a common axis. The direction in which the axis of the two through-holes  14   a  extend is orthogonal to the axis of the shaft hole  33 . 
     &lt;Groove  41   b&gt;   
     As shown in  FIG.  4   , the shaft body  41  includes a groove  41   b  provided in an end face  41   a  at the second end. The groove  41   b  extends across the end face  41   a  of the shaft body  41 . The groove  41   b  extends in the radial direction of the shaft body  41 . 
     The groove  41   b  extends in a direction that is orthogonal to the axis of the through-hole  14   a  when the manual shaft  40  is in the first switching position. As shown in  FIG.  7   , the groove  41   b  extends along the axis of the through-holes  14   a  when the manual shaft  40  is in the second switching position and is prevented from moving toward the first switching position by the fixing pin  46  engaged with the locking slot  49 . 
     &lt;Padlock  60 &gt; 
     As shown in  FIG.  8   , a padlock  60 , which is a locking member, can be attached to the electromagnetic valve  11  with the manual shaft  40  located in the second switching position. The padlock  60  includes a body  61  and a shackle  62 . The shackle  62  has the shape of a U. In the present embodiment, the padlock  60  is attached to the electromagnetic valve  11  by inserting the shackle  62  into the two first through-holes  14   a . The padlock  60  is locked up to prevent the manual shaft  40  from being manually operated. The shackle  62  traverses the opening  33   a  of the shaft hole  33 . In other words, the shackle  62  partially blocks the opening  33   a  of the shaft hole  33 . Thus, when the manual shaft  40  is in the second switching position, the shackle  62  of the padlock  60  can be inserted into the two through-holes  14   a  while partially blocking the opening  33   a . The shackle  62  is engaged with the groove  41   b . Thus, the groove  41   b  is an engagement portion with which the shackle  62 , which partially blocks the opening  33   a , is engaged. 
     When the manual shaft  40  is in the second switching position and is prevented from moving toward the first switching position, the shackle  62  is engaged with the groove  41   b  to prevent the manual shaft  40  from rotating. Therefore, the groove  41   b  extends along the axis of the two through-holes  14   a  when the manual shaft  40  is in the second switching position and is prevented from moving toward the first switching position. 
     &lt;Operation&gt; 
     Operation of the present embodiment will now be described. 
     For example, there may be a case in which voltage is applied to the first pilot valve V 1 , and voltage is not applied to the second pilot valve V 2 , so that the spool valve  30  is in the first position as shown in  FIG.  1   . At this time, if the manual shaft  40  has been switched to in the first switching position as shown in  FIGS.  1  and  2   , the fluid supplied by the fluid supply source is supplied to the first pressure chamber X 5  of the actuator X 1  through the piping, the supply passage  51 , the supply port P 1 , the first output port A 1 , the first output passage  52 , and the first pipe T 1 . When the fluid is supplied to the first pressure chamber X 5 , the piston X 3  is pushed into the second pressure chamber X 6 , so that the piston rod X 4  moves in a direction of protruding from the cylinder tube X 2 . Further, the fluid in the second pressure chamber X 6  is discharged to the atmosphere through the second pipe T 2 , the second output passage  53 , the second output port A 2 , the second discharge port R 2 , the second discharge passage  55 , and the piping. In this manner, the actuator X 1 , which is connected to the first output passage  52  and the second output passage  53 , is driven by the fluid flowing through the first output passage  52  and the second output passage  53 . 
     When maintenance of the actuator X 1  is performed, the operation of the actuator X 1  must be stopped. The manual shaft  40  is thus manually switched from the first switching position to the second switching position. In the manual operation, the operator first pushes the manual shaft  40  through the opening  33   a  of the shaft hole  33  until the manual shaft  40  reaches the second switching position. At this time, the manual shaft  40  is pushed against the urging force of the urging spring  47  with the fixing pin  46  located in the unlocking slot  48 . After the manual shaft  40  is moved from the first switching position to the second switching position, the manual shaft  40  is rotated 90° so as to move the fixing pin  46  into the locking slot  49 . This restricts the manual shaft  40  from being moved toward the first switching position by the urging force of the urging spring  47 . That is, the locking slot  49  and the fixing pin  46 , which is engaged with the locking slot  49 , maintain the manual shaft  40  in the second switching position. In a state in which the manual shaft  40  has been moved from the first switching position to the second switching position, the insertion hole  14   h  restricts the stopper member  42  and the shaft body  41  from rotating together when the shaft body  41  rotates in the shaft hole  33  about the axis. 
     For example, if the manual shaft  40  is switched from the first switching position to the second switching position when the spool valve  30  is located in the first position, the projection  45  protrudes into the valve hole  17  through the insertion hole  14   h  and is engaged with the first recess  31  as shown in  FIG.  5   . This restricts movement of the spool valve  30 . The spool valve  30  is thus maintained in the first position. As a result, the pressure of the fluid between the first output passage  52  and the actuator X 1  is maintained. The operation of the actuator X 1  is thus stopped. Specifically, the actuator X 1  is held in a state in which the piston X 3  has moved to a first movement end, at which the volume of the second pressure chamber X 6  is minimized. 
     For example, if the manual shaft  40  is switched from the first switching position to the second switching position when the spool valve  30  is located in the second position, the projection  45  protrudes into the valve hole  17  through the insertion hole  14   h  and is engaged with the second recess  32 . This restricts movement of the spool valve  30 . The spool valve  30  is thus maintained in the second position. As a result, the pressure of the fluid between the second output passage  53  and the actuator X 1  is maintained. The operation of the actuator X 1  is thus stopped. Specifically, the actuator X 1  is held in a state in which the piston X 3  has moved to a second movement end, at which the volume of the first pressure chamber X 5  is minimized. 
     In this manner, the manual shaft  40  restricts movement of the spool valve  30  relative to the valve hole  17  so as to maintain the pressure of the fluid between the first output passage  52  and the actuator X 1  or the pressure of the fluid between the second output passage  53  and the actuator X 1 . Further, since the manual shaft  40  prevents the spool valve  30  of the electromagnetic valve  11  from malfunctioning, the pressure of the fluid between the first output passage  52  and the actuator X 1  or the pressure of the fluid between the second output passage  53  and the actuator X 1  is unlikely to change. The operation of the actuator X 1  is thus stopped reliably. 
     &lt;Advantages&gt; 
     The above-described embodiment has the following advantages. 
     (1) For example, if the manual shaft  40  is located in the second switching position when the spool valve  30  is located in the first position, the projection  45  protrudes into the valve hole  17  and is engaged with the first recess  31 , so as to restrict movement of the spool valve  30  relative to the valve hole  17 . Thereby, the pressure of the fluid between the first output passage  52  and the actuator X 1  is maintained. The operation of the actuator X 1  is thus stopped. Therefore, in order to stop the operation of the actuator X 1 , it is not necessary, for example, to interpose a stopper valve between the electromagnetic valve  11  and the manifold base  50  as in the related art. Hence, unlike the related art, a pressure loss of the fluid does not occur due to the flow of fluid via a stopper valve. As a result, a sufficient flow rate of the fluid supplied to and discharged from the actuator X 1  is ensured. In this manner, the operation of the actuator X 1  is stopped while ensuring a sufficient flow rate of fluid supplied to and discharged from the actuator X 1 . 
     (2) The padlock  60  can be attached to the electromagnetic valve  11  with the manual shaft  40  located in the second switching position. When located in the second switching position, the manual shaft  40  cannot be operated manually if the padlock  60  is attached to the electromagnetic valve  11 . This prevents the operator from accidentally moving the manual shaft  40  from the second switching position to the first switching position. If the operator locks up the padlock  60  attached to the electromagnetic valve  11 , the manual shaft  40  is prevented from being operated manually by a third person against the will of the operator. Accordingly, the reliability of the electromagnetic valve manifold  10  is improved. 
     (3) When the manual shaft  40  is in the second switching position, the shackle  62  of the padlock  60  is inserted into the two through-holes  14   a  while partially blocking the opening  33   a . With this configuration, when the padlock  60  is attached to the electromagnetic valve  11 , the shackle  62  of the padlock  60  is inserted into the two through-holes  14   a . This stabilizes the attachment of the padlock  60  to the electromagnetic valve  11 . Further, the padlock  60  is attached to the electromagnetic valve  11  with the shackle  62  of the padlock  60  partially blocking the opening  33   a  of the shaft hole  33 . The shackle  62  of the padlock  60  traverses the opening  33   a . The padlock  60  thus prevents the manual shaft  40  located in the second switching position from being manually operated through the opening  33   a  of the shaft hole  33 . 
     (4) After the manual shaft  40  is moved from the first switching position to the second switching position against the urging force of the urging spring  47  with the fixing pin  46  in the unlocking slot  48 , the fixing pin  46  is moved into the locking slot  49  to allow the manual shaft  40  to rotate. When the fixing pin  46  is moved into the locking slot  49 , the manual shaft  40  is prevented from moving toward the first switching position and is maintained in the second switching position. Further, the shackle  62  of the padlock  60  is engaged with the groove  41   b  of the manual shaft  40  when the manual shaft  40  is located in the second switching position. This restricts the manual shaft  40  from rotating in the second switching position. The manual shaft  40  is thus prevented from rotating in the second switching position against the will of the operator. Therefore, the manual shaft  40  is prevented from moving from the second switching position to the first switching position by the urging force of the urging spring  47  against the will of the operator. As a result, the manual shaft  40  will not be switched to the first switching position accidentally. Accordingly, the reliability of the electromagnetic valve manifold  10  is further improved. 
     (5) The two through-hole  14   a  have a common axis. The groove  41   b  extends along the axis of the two through-holes  14   a  when the manual shaft  40  is in the second switching position. Thus, the shackle  62  of the padlock  60 , which is passed through the two through-holes  14   a  and traverses the opening  33   a  of the shaft hole  33 , can be easily engaged with the first groove  41   b.    
     (6) Since the projection  45  has the shape of a flat plate, it is easy to ensure a contact area between the projection  45  and the first recess  31  or the second recess  32 . Therefore, movement of the spool valve  30  relative to the valve hole  17  is easily restricted by causing the projection  45  to be engaged with the first recess  31  or the second recess  32 . Also, the insertion hole  14   h  guides the projection  45  when the manual shaft  40  moves between the first switching position and the second switching position. After the manual shaft  40  is moved from the first switching position to the second switching position, the insertion hole  14   h  restricts the stopper member  42  and the shaft body  41  from rotating together when the shaft body  41  rotates in the shaft hole  33  about the axis. Therefore, the projection  45  is properly engaged with the first recess  31  or the second recess  32  when the manual shaft  40  is located in the second switching position. 
     (7) The manual shaft  40  is capable of restricting movement of the spool valve  30  relative to the valve hole  17  when the spool valve  30  is located in the first position. The manual shaft  40  is also capable of restricting movement of the spool valve  30  relative to the valve hole  17  when the spool valve  30  is located in the second position. Thus, the actuator X 1  is in one of two states when the actuator X 1  is not operating. Therefore, it is possible to appropriately select the state of the actuator X 1  when the actuator X 1  is not operating. 
     (8) In the present embodiment, it is not necessary, for example, to interpose a stopper valve between the electromagnetic valve  11  and the manifold base  50  as in the related art. Accordingly, the size of the electromagnetic valve manifold  10  in the mounting direction is reduced as compared with a case in which a stopper valve is interposed between the electromagnetic valve  11  and the manifold base  50 . 
     &lt;Modifications&gt; 
     The above-described embodiment may be modified as follows. The above-described embodiment and the following modifications can be combined as long as the combined modifications remain technically consistent with each other. 
     In above-described embodiment, for example, when multiple electromagnetic valves  11  are arranged side by side, a common padlock may be used for all the electromagnetic valves  11 . The shackle of the common padlock is passed through the through-holes  14   a  of all the electromagnetic valves  11  and is engaged with the grooves  41   b  of all the manual shafts  40 . This eliminates the necessity to operate multiple padlocks prepared for each of the electromagnetic valves  11 . This simplifies the procedure. 
     In the above-described embodiment, the first recess  31  or the second recess  32  may be omitted as long as the spool valve  30  includes at least one recess in the outer surface of the spool valve  30 . 
     In the above-described embodiment, the spool valve  30  may further include a third recess. In this case, the projection  45  is engaged with the third recess when the spool valve  30  is located in a neutral position. The third recess is located between the first recess  31  and the second recess  32 . Thus, the actuator X 1  is in one of three states when the actuator X 1  is not operating. Therefore, it is possible to appropriately select the state of the actuator X 1  when the actuator X 1  is not operating. 
     In the above-described embodiment, the electromagnetic valve manifold  10  does not necessarily need to be configured such that the operation block  14  is a separate component from the valve casing  12 , but may be configured such that a structure equivalent to the operation block  14  is integrally formed with the valve casing  12 . In this case, the shaft hole  33  is formed in the valve casing  12 . Also, the shaft hole  33  is accommodated in the manual shaft  40 . 
     In the above-described embodiment, the two through-holes  14   a  do not necessarily need to have a common axis. This modification is possible if the shackle  62  of the padlock  60  inserted into the through-holes  14   a  is engaged with part of the manual shaft  40 . 
     In the above-described embodiment, the padlock  60  does not necessarily need to be attached to the electromagnetic valve  11 . 
     In the above-described embodiment, the electromagnetic valve  11  may be a four-port electromagnetic valve from which, for example, the second discharge port R 2  is omitted. That is, any type of electromagnetic valve may be used as the electromagnetic valve  11  as long as the electromagnetic valve  11  includes at least one discharge port. The electromagnetic valve  11  may be a three-port electromagnetic valve that includes a supply port, an output port, and a discharge port. 
     Various changes in form and details may be made to the examples above without departing from the spirit and scope of the claims and their equivalents. The examples are for the sake of description only, and not for purposes of limitation. Descriptions of features in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if sequences are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined differently, and/or replaced or supplemented by other components or their equivalents. The scope of the disclosure is not defined by the detailed description, but by the claims and their equivalents. All variations within the scope of the claims and their equivalents are included in the disclosure.