Patent Publication Number: US-6660949-B2

Title: Safety switch actuator

Description:
TECHNICAL FIELD 
     The present invention relates to a safety switch which is mounted on a wall surface of the doorway of a room for installing an industrial machine or the like, and which discontinues power supply to the industrial machine or the like when the door at the doorway is opened. 
     BACKGROUND ART 
     In a room or factory which accommodates an industrial machine, or in a danger zone around an industrial machine itself, it is required to install a system for locking the drive of the machine. The locking system operates when the door at the doorway for the room or danger zone is not closed completely, in order to prevent accidents in which an operator may get caught in the machine and injured. 
     With regard to a common locking system, a limit switch is disposed at the slidable portion of the door. The system provides power to the industrial machine inside the room, only when the limit switch detects the closure of the door. 
     Nevertheless, this locking system is not a perfect safety measure, because the machine inside the room can be turned operable, without closing the door, by manipulating the actuator of the limit switch. 
     In this respect, the applicant of the present invention has already proposed a safety switch for preventing such wrong operations (Japanese Patent Laid-open Publication No. H6-76674 (JP-A-6-76674). 
     The proposed safety switch has an operation section and a switch section, and comprises a switch body which includes a key insertion hole formed in the casing of the operation section (see FIG. 1) and an actuator composed of a base and an operation key provided therewith. The switch body is mounted on the wall surface around the doorway of the room, whereas the actuator is secured on the door (sliding or revolving door) at the doorway. On closure of the door, the operation key of the actuator enters the operation section through the key insertion hole in the switch body, causing the contact block housed in the switch section to switch over its moving contact. This switch-over action directs the circuit connection to the main circuit (power supply circuit for the industrial machine) and sets the machine in the room ready for operation. 
     In another use, the safety switch is disposed at a connection point with a mobile device which is connected to a teaching device or similar device body. When the mobile device is properly connected to the device body, the operation key of the actuator enters the switch body of the safety switch to set the device body to an operable state. 
     When the actuator for these safety switches is mounted on the door, the operation key is oriented horizontally or vertically, depending on the conditions of use (e.g. installation posture of the switch body). 
     However, in many of the conventional actuators, the operation key is fixedly held on the base with no freedom in movement. As illustrated in FIG. 29, if the actuator is used for a revolving door  10  with a small radius of revolution, the tip of an operation key  502  may interfere with a switch body  100  when the revolving door  10  closes. Because of this problem, a fixed actuator is not applicable to the revolving door  10  having a small revolution radius. 
     In order to solve this problem, another actuator (an operation key device for a safety switch) is disclosed in Japanese Patent Laid-open Publication No. H11-213820 (JP-A-11-213820), wherein the operation key is mounted on the base in such a manner as to be capable of swinging in orthogonal directions (horizontal and vertical directions). According to this actuator, however, the operation key is constantly swingable in two directions (horizontal and vertical directions), and held in a tilted posture both horizontally and vertically. Under these conditions, it is difficult to position this actuator relative to the switch body. 
     Made in view of such circumstances, the present invention intends to provide an actuator in which the operation key can move relative to the base, whereby the actuator becomes applicable to a revolving door with a small revolution radius and the like, and in which the movable direction of the operation key can be selectively changed over into either of the horizontal direction or the vertical direction. 
     DISCLOSURE OF THE INVENTION 
     In order to achieve the above object, the actuator of the present invention comprises an operation key to be inserted into a key insertion hole formed in the safety switch, and a base, characterized in that the operation key is held on the base and capable of freely swinging in two orthogonal directions, and also characterized in comprising means for selectively restricting the swinging movement of the operation key to either of the two directions. 
     The actuator of the present invention gives the operation key a freedom of being swingable in two directions (horizontal and vertical directions). Even if the operation key may interfere with the switch body on entry into the key insertion hole in the switch body, the operation key can swing to avoid such interference. Therefore, this actuator can be used, for example, for a revolving door with a small radius of revolution. Besides, the swinging direction of the operation key can be selectively changed over into either the horizontal direction or the vertical direction, so that the operation key is allowed to swing only in a direction in which the freedom is required. As a result, the safety switch can be installed without any difficulty in positioning the actuator relative to the switch body. 
     The actuator of the present invention may be provided with two engagement spaces which are formed in the base and a guide stopper which is configured to fit into each of the engagement spaces. By fitting the guide stopper selectively into either of the two engagement spaces, it is possible to restrict the swinging direction of the operation key to one direction. 
     The actuator of the present invention may comprise an adjustment mechanism for independently adjusting a swinging range of the operation key in each swinging direction. Thereby, the swinging range of the operation key can be easily set to a suitable range, depending on the conditions of use (e.g. revolution radius of a revolving door). 
     If the actuator of the present invention comprises an elastic member for biasing the operation key in each swinging direction, the operation key can be held at a certain position under an elastic force. In this case, the operation key may be biased in each swinging direction by a torsion force and a compression force both generated by a helical coil spring, so that the number of parts can be reduced (thus, the cost is reduced). 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a perspective view schematically showing the structure of a safety switch. 
     FIGS.  2 (A) and  2 (B) and  3 (A) and  3 (B) describe operations of the safety switch. 
     FIG.  4 (A) is a vertical sectional view of an embodiment of the present invention, and FIG.  4 (B) is a rear view thereof. 
     FIG. 5 is a front view thereof. 
     FIG. 6 is a sectional view of the embodiment shown in FIG. 5, taken along the line A—A. 
     FIG. 7 is a sectional view taken along the line C—C in FIG.  4 . 
     FIG. 8 is a perspective view of the guide stopper to be used in the embodiment of FIG.  4 . 
     FIG.  9 (A) is a vertical sectional view showing an example of the embodiment of FIG. 4 in use, and FIG. 9 (B) is a rear view thereof. 
     FIG.  10 (A) is a vertical sectional view showing another example of the embodiment of FIG. 4 in use, and FIG.  10 (B) is a rear view thereof. 
     FIG. 11 is a sectional view of the example shown in FIG. 10, taken along the line B—B. 
     FIG. 12 is a front view of the example shown in FIG.  10 . 
     FIGS. 13 and 14 describe the actions in the embodiment of the present invention. 
     FIG. 15 is a perspective view showing an example of the mechanism for adjusting the swinging range of the operation key. 
     FIG. 16 is a plan view showing another example of the mechanism for adjusting the swinging range of the operation key. 
     FIG.  17 (A) is a plan view schematically showing the structure of another embodiment of the present invention, and FIG.  17 (B) is a side view thereof. 
     FIG.  18 (A) is a plan view schematically showing the structure of the another embodiment of the present invention, and FIG.  18 (B) is a side view thereof. 
     FIG. 19 is a view taken in the direction of arrows D—D in FIG.  17 . 
     FIGS. 20 and 21 are sectional views schematically showing the structure of yet another embodiment of the present invention. 
     FIG. 22 is a sectional view taken along the line E—E in FIG.  20 . 
     FIG. 23 is a view taken in the direction of arrows F—F in FIG.  20 . 
     FIG. 24 is a sectional view taken along the line G—G in FIG.  23 . 
     FIGS. 25 and 26 are sectional views schematically showing the structure of still another embodiment of the present invention. 
     FIG. 27 is a sectional view taken along the line H—H in FIG.  25 . 
     FIG. 28 is a view taken in the direction of arrows I—I in FIG.  25 . 
     FIG. 29 describes a problem concerning conventional actuators. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Embodiments of the present invention are hereinafter described, based on the drawings. 
     To begin with, the schematic structure of a safety switch is mentioned with reference to FIGS. 1 to  3 . 
     The safety switch of this example is electrically connected to an industrial machine which is installed in a room, and mainly composed of a switch body  100  and an actuator  1  (see FIG.  4 ). The switch body  100  is secured on the wall surface in the periphery of the doorway of the room. The actuator  1  is fixed on the revolving door. 
     The switch body  100  comprises an operation section  101  into which an operation key  2  of the actuator  1  is inserted, and a switch section  102  which contains a built-in contact block (not shown). The operation section  101  has two key insertion holes (slit holes)  103 ,  104  which enable selection of the insertion direction of the actuator  1 . 
     The operation section  101  houses a plate cam  111  which is rotatably held by a cam shaft  115 . The plate cam  111  causes displacement of an operation rod  105  of the contact block (not shown) which is housed in the switch section  102 . The outer circumferential surface of the plate cam  111  has rectangular recesses  113 ,  114  which correspond to the two key insertion holes  103 ,  104  in the operation section  101 . 
     With regard to the safety switch of this structure, FIG. 2 illustrates entry of the operation key  2  into the operation section  101 , through the key insertion hole  103 . At this moment, a push piece  2   b  of the operation key  2  comes into contact with the plate cam  111  (FIG.  2 (A)). Further entry of the operation key  2  causes the plate cam  111  to rotate, and, in turn, the rotation of the plate cam  119  causes the operation rod  105  of the switch section  102  to move toward the operation section  101 . When the operation key  2  advances as far as the insertion end, the connection contact of the contact block is switched over, and the push piece  2   b  of the operation key  2  fits into the recess  113  in the plate cam  111  (FIG.  2 (B)). In the state shown in FIG.  2 (B), where the operation key  2  is pulled out, the retreat of the operation key  2  causes the plate cam  111  to rotate in the reverse direction relative to the above direction. In this connection, the operation rod  105  moves toward the switch section  102  to switch over the contact connection back to the initial state. 
     Likewise, FIG. 3 describes entry of the operation key  2  into the operation section  101 , through another key insertion hole  104  in the operation section  101 . Referring to FIG.  3 (A), the push piece  2   b  of the operation key  2  comes into contact with the plate cam  111 , and further entry of the operation key  2  causes the plate cam  111  to rotate. In response to the rotation of the plate cam  111 , the operation rod  105  of the switch section  102  moves toward the operation section  101  to switch over the connection contact, and the push piece  2   b  of the operation key  2  fits into the recess  114  in the plate cam  111  (FIG.  3 (B)). In this state, when the operation key  2  is pulled out, the plate cam  111  rotates backwards, so that the operation rod  105  moves toward the switch section  102  to switch over the connection contact. 
     Incidentally, the operation section  101  is internally formed with guide surfaces  101   a ,  101   b  in order to guide the front end portion of the operation key  2  after it enters the key insertion hole  103 ,  104  (see FIGS.  13  and  14 ). 
     Turning now to FIGS. 4 to  12 , the actuator  1  of this embodiment is described in detail. 
     The actuator  1  comprises an operation key  2  and a base  3 . The operation key  2  is a metal component or the like. As can be seen in FIG. 4, the portion to be inserted into the operation section  101  is integrally composed of a push piece  2   b  at the front end portion and a pair of support pieces  2   c  for holding both ends thereof. The front end portion of the pair of support pieces  2   c  protrude ahead of the push piece  2   b.  The extremities of protrusions  2   d  are chamfered at about 45°. The operation key  2  is held on a support shaft  33  provided in the base  3 , and capable of freely swinging in two directions that intersect at right angles (horizontal and vertical directions). Its rear end includes an integrally formed contact piece  2   a.    
     The base  3  is made of a resin such as polyamide 6,6 (PA66), and integrally composed of a key holding part  31  and a mounting part  32 . A mounting slot (elliptic slot)  32   a  is formed at each end of the mounting part  32 . 
     The key holding part  31  includes a hollow structure which penetrates from the front to the back of the base  3 . The front part houses a support shaft  33 . Inside the key holding part  31 , as shown in FIG. 6, a support point  31   a  locates opposite to the contact piece  2   a  of the operation key  2  which is held on the support shaft  33 . An inclined surface  31   b  is defined from the support point  31   a  to the front of the base  3 , with the surface being tilted outwardly toward the front. 
     The support shaft  33  is wrapped by a helical torsion spring  5 . One end  51  of the helical torsion spring  5  is checked at the operation key  2 , whereas another end  52  is checked at an inner surface  31   c  of the key holding part  31  in such a manner that a torsion force is imposed on the helical torsion spring  5  itself. In addition, the helical torsion spring  5  is squeezed, in a compressed state, between the operation key  2  and an inner surface  31   d  of the key holding part  31  (the surface opposite to the inclined surface  31   b ). The torsion force and the compression force of the helical torsion spring  5  presses the operation key  2  in the horizontal and vertical directions, respectively. 
     At the side of the key holding part  31 , two female threaded holes (through-holes)  61 ,  71  are machined. Adjustment screws (e.g. screws with a hexagonal bore)  6 ,  7  are respectively screwed in the female threaded holes  61 ,  71 . By operating these adjustment screws  6 ,  7 , it is possible to adjust the horizontal swinging range and the vertical swinging range of the operation key  2  independently. 
     In the rear of the base  3 , engagement spaces  34 ,  35  are provided beside a first major surface (the surface not facing the support point  31   a ) of the contact piece  2   a  of the operation key  2  and laterally of the contact piece  2   a.  These engagement spaces  34 ,  35  are defined by guide grooves  34   a,    35   a  and guide projections  34   b,    35   b  (see FIG. 7) which fit guide flanges  4   a  and a guide groove  4   b  of a guide stopper  4  whose configuration is illustrated in FIG.  8 . When the guide stopper  4  is selectively fitted into either of these two engagement spaces  34 ,  35 , the swinging direction of the operation key  2  is restricted to either the horizontal direction or the vertical direction. 
     Specifically, as shown in FIG. 9, when the guide stopper  4  is fitted into the engagement space  34  which locates beside the first major surface of the contact piece  2   a  of the operation key  2 , the guide stopper  4  touches the first major surface  21   a  of the contact piece  2   a.  In this situation, the guide stopper  4  and the support point  31   a  restrict the vertical movement of the operation key  2 , allowing the operation key  2  to swing only in the horizontal direction. On the other hand, referring to FIG. 10, if the guide stopper  4  is fitted into the engagement space  35  which locates laterally of the contact piece  2   a,  the guide stopper  4  touches the lateral surface  22   a  of the contact piece  2   a,  and prevents the horizontal movement of the operation key  2 . In this case, the operation key  2  is allowed to swing only in the vertical direction. Further referring to FIG. 11, since the helical torsion spring  5  constantly biases the contact piece  2   a  against the support point  31   a,  the operation key  2  swings about the support point  31   a  as fulcrum. 
     FIGS. 13 and 14 and the following description relate to the actions of the present embodiment. 
     FIG. 13 represents a posture for mounting the switch body  100  In this arrangement, the guide stopper  4  is fitted into the engagement space  34  (beside the first major surface of the contact piece  2   a ) of the actuator  1 , as shown in FIG. 9, thereby effecting the horizontal swinging movement only. The actuator  1  is mounted on the revolving door  10  in the posture illustrated in FIG.  13 . The swinging range of the operation key  2  should be adjusted in advance, such that the operation key  2  lies parallel to the insertion direction of the operation section  101  when the revolving door  10  turns and the front end portion of the operation key  2  starts to enter the key insertion hole  103  in the operation section  101 . 
     According to the example of FIG. 13, while the revolving door  10  closes, the front end portion of the operation key  2  starts to enter the key insertion hole  103 . Once the front end portion establishes contact with the guide surfaces  101   a,  the operation key  2  starts to swing (in the horizontal direction). In the meantime, the operation key  2  advances along the guide surfaces  101   a  deeply enough to cause rotation of the plate cam  111  in the operation section  101  (see FIG.  2 (B)). Because of the horizontal swingability of the operation key  2 , the contact of the front end portion of the operation key  2  with the switch body  100  generates nothing but an elastic force of the helical torsion spring  5 , and never causes a strong force that may adversely affect the switch body  100 . 
     In contrast, FIG. 14 illustrates another posture for mounting the switch body  100 . In this arrangement, the guide stopper  4  is fitted into the engagement space  35  (laterally of the contact piece  2   a ) of the actuator  1 , as shown in FIG. 10, thereby effecting the vertical swinging movement only. The actuator  1  is mounted on the revolving door  10  in the posture illustrated in FIG.  14 . 
     According to the example of FIG. 14, while the revolving door  10  closes, the front end portion of the operation key  2  starts to enter the key insertion hole  104 . Once the front end portion establishes contact with the guide surface  101   b,  the operation key  2  starts to swing (in the vertical direction). In the meantime, the operation key  2  advances along the guide surface  101   b  deeply enough to cause rotation of the plate cam  111  in the operation section  101  (see FIG.  3 (B)). Because of the vertical swingability of the operation key  2 , the contact of the front end portion of the operation key  2  with the switch body  100  produces nothing but an elastic force of the helical torsion spring  5 , and never causes a strong force that may adversely affect the switch body  100 . 
     With regard to the embodiment illustrated in FIGS. 4 to  12 , the swinging range of the operation key  2  can be adjusted by operating the adjustment screws  6 ,  7  provided in the base  3 . Hence, it is possible to set a swinging range in a simple manner, depending on the conditions of using the safety switch, that is, the revolution radius of the revolving door  10 . The mechanisms for adjusting the swinging range include many variations, in addition to the adjustment screws  6 ,  7 . Some examples are given in FIGS. 15 and 16 below. 
     In the adjustment mechanism illustrated in FIG. 15, a base  203  includes two recesses  231 ,  232  having internally serrated steps  231   a,    232   a.  Also provided is an adjustment block (stopper)  204  formed with serrated steps  204   a  which can fit with each of the recesses  231 ,  232 . With this structure, the swinging range of the operation key is adjustable step by step, by altering the manner of fitting the adjustment blocks  204  into the recesses  231 ,  232 , namely, the manner of engaging the serrated steps  204   a  of the adjustment blocks  204  with the serrated steps  231   a,    232   a  of the recesses  231 ,  232 . Additionally, in the adjustment mechanism of FIG. 15, a band  205  is wound around the sides of the base  203  to prevent disengagement of the adjustment block  204 . 
     In the adjustment mechanism illustrated in FIG. 16, the rear end of an operation key  302  is integrated with an engaging piece  302   a.  A base  303  includes pin holes  303   a  . . .  303   a  which are provided at a predetermined pitch along the circumference centered on the swinging center of the operation key  302 . Based on a proper choice, an engaging pin  304  is inserted into any one of these pin holes  303   a  . . .  303   a,  so that the swinging range of the operation key  302  can be adjusted step by step. Incidentally, in order to bias the operation key  2  horizontally and vertically, the above embodiments utilize the torsion force and compression force of the single helical torsion spring  5 . Instead, the operation key  2  may be independently biased in the horizontal direction and the vertical direction with separate elastic members. 
     In the above embodiments, an elliptic counterbore  32   b  is machined around the mounting slot  32   a  in the mounting part  32  of the base  3  (see FIG.  12 ). Alternatively, a hexagonal counterbore may be machined around the mounting slot  32   a,  into which a hexagonal nut is fitted and screwed. According to this arrangement, the actuator can be mounted on the revolving door, as screwed from the backside of the actuator-mounting surface of the revolving door. 
     FIGS. 17 and 18 represent another embodiment of the present invention. 
     This embodiment is characterized in that a guide stopper  40  is equipped with a spring piece  50  for biasing the operation key  2 . The spring piece  50  is bent in the form of the letter L, and one end thereof is fixed on a support block  42 . As illustrated in FIG. 19, the support block  42  is a rectangular solid which appears a square from a front view. The support block  42  is fitted in a square-sectioned recess  41   a  formed in a guide stopper body  41 . By varying this fitting orientation, the orientation of the spring piece  50  can be altered by 90 degrees relative to the guide stopper body  41 . 
     According to this embodiment, as shown in FIGS.  17 (A) and (B), the guide stopper  40  is disposed in contact with the first major surface of the contact piece  2   a  of the operation key  2 , with the spring piece  50  touching the lateral surface of the contact piece  2   a.  In this state, the operation key  2  can swing only in the horizontal direction, and receives a horizontal bias force generated by the spring piece  50 . On the other hand, in FIGS.  18 (A) and (B), the orientation of the spring piece  50  is turned 90 degrees relative to the guide stopper body  41 . In this case, the guide stopper  40  lies in contact with the lateral surface of the contact piece  2   a  of the operation key  2 , with the spring piece  50  touching the first major surface of the contact piece  2   a.  Now, the operation key  2  is allowed to swing only in the vertical direction, and receives a vertical bias force generated by the spring piece  50 . 
     FIGS. 20 and 21 are schematic sectional views showing the structure of yet another embodiment of the present invention. FIG. 22 is a sectional view taken along the line E—E in FIG.  20 . FIG. 23 is a view taken in the direction of arrows F—F in FIG.  20 . FIG. 24 is a sectional view taken along the line G—G in FIG.  23 . 
     This embodiment is characterized by a change-over box  404  which is the means for selectively changing the swinging direction of an operation key  402 . 
     The change-over box  404  is a rectangular box (with a square front) which opens only at its front side (an opening  441 ). The opposite side is defined by an inclined surface  442 , in the center of which a slit-shaped guide groove  443  extends in the inclination direction. The change-over box  404  can be fitted from the back of the base  403 , into a square-sectioned engagement space  431  in the base  403 . In order to secure the change-over box  404 , pressure plates  432  are provided on the rear surface of the base  403 . 
     The operation key  402  is held in the base  403  by means of a support shaft  433 . The rear portion of the operation key  402  is equipped with a spring washer  421 , at which one end of a coil compression spring  405  is anchored. The extreme end of the coil compression spring  405  is turned to the center of the spring, where the extreme end is bent outwardly. 
     Referring to FIG. 20 for the assembly in this embodiment, the change-over box  404  is fitted into the engagement space  431  in the base  403 , with the extreme end  451  of the coil compression spring  405  being aligned with the guide groove  443 . In the state of FIG. 20, the operation key  402  is held as inclined downwards (based on the figure), due to the action of the elastic force of the coil compression spring  405  and the inclined surface  442 . In this state, an upward force (based on the figure) which acts on the front end portion of the operation key  402  causes swinging movement (horizontal) of the operation key  402 . When the acting force ceases to exist, the operation key  402  returns to the initial state. 
     According to this embodiment, the change-over box  404  can be removed from the base  403 . The removed change-over box  404  is turned 90 degrees relative to the base  403 , and re-inserted into the engagement space  431  in the base  403  in the same manner as above. This alternative mode is illustrated in FIG. 21, in which the operation key  402  is allowed to swing only in the vertical direction. Depending on the swinging direction of the operation key  402 , the change-over box  404  can be positioned in four different orientations. 
     FIGS. 25 and 26 are sectional views schematically showing the structure of still another embodiment of the present invention. FIG. 27 is a sectional view taken along the line H—H in FIG.  25 . FIG. 28 is a view taken in the direction of arrows I—I in FIG.  25 . 
     This embodiment is characterized by a change-over box  504  which is the means for selectively changing the swinging direction of an operation key  502 . 
     The change-over box  504  is a rectangular box (with a square front) which opens only at its front side (an opening  541 ). The change-over box  504  can be fitted from the back of the base  503 , into a square-sectioned engagement space  531  in the base  503 . In order to secure the change-over box  504 , pressure plates  532  are provided on the rear surface of the base  503 . 
     Similar to the above embodiment, the base  503  contains a support shaft  533 , and the operation key  502  is held on the support shaft  533 . The rear portion of the operation key  502  is equipped with a spring seat  521 . A coil spring  505  is placed between the spring seat  521  and the inclined surface  542  of the change-over box  504 . The extreme end  511  of the coil spring  505  is secured on the change-over box  504 . 
     Referring to FIG. 25 for the assembly in this embodiment, the change-over box  504  is fitted into the engagement space  531  in the base  503 , with the change-over box  504  accommodating the coil spring  505 . In the state of FIG. 25 (the free state) where the spring seat  521  of the operation key  502  is subjected to the force of the coil spring  505 , the spring seat  521  stands parallel to the inclined surface  542  to keep the operation key  502  inclined. In this state, the operation key  502  can be inserted into the insertion hole  103  ( 104 ), so that a downward force (based on the figure) is imposed on the front end portion of the operation key  502 . Under this force, the coil spring  505  is compressed at a part  505   a  located along one corner (the bottom corner in the figure) of the inclined surface  542 , orienting the operation key  502  in a parallel (horizontal) posture (FIG.  26 ). Afterwards, when the operation key  502  is pulled out of the insertion hole  103  ( 104 ), the initial state (FIG. 25) is recovered by the recovery force of the compressed part  505   a  of the coil spring  505 . 
     Similar to the foregoing embodiment, this embodiment allows the change-over box  504  to be removed from the base  503 . The removed change-over box  504  is turned 90 degrees relative to the base  503 , and reinserted into the engagement space  531  in the base  503  as described above. This arrangement enables the operation key  502  to alter its swinging directions (by 90 degrees). Depending on the swinging direction of the operation key  502 , the change-over box  504  can be positioned in four different orientations. 
     According to the present invention, the actuator for a safety switch gives freedom to the operation key. Therefore, the actuator can be effectively utilized not only for a revolving door with a small revolution radius but also for a connection point with a mobile device or for a sliding door, where the positional relationship between the switch body and the actuator requires some allowance. 
     Industrial Applicability 
     As described above, the actuator for a safety switch according to the present invention can be used for a revolving door with a small revolution radius, to give an example. It is also applicable to a sliding door, even when the switch body and the mounting surface of the actuator may not match. As a result, the actuator can be used in a wider range of application, and, further, in various manners according to user&#39;s individual objects.