Non-contact safety switch

Abstract

To improve flexibility of arrangement of a sensor head of a non-contact safety switch.SOLUTION: A safety switch 1 includes an actuator and a sensor head 2. The actuator has an RFID tag. The sensor head 2 includes a head body 21 and an antenna part 22. The head body 21 has a control unit 215 of an RFID reader 205. The antenna part 22 has an antenna 225 of the RFID reader 205. The antenna part 22 is a flat-plate-like member which is connected to the head body 21 in a displaceable manner. The antenna part 22 is connected to the head body 21 through a rotary shaft J1 extending linearly along an end edge of the antenna part 22. The antenna part 22 rotates around the rotary shaft J1 to be displaced relative to the head body 21. The structure improves flexibility of arrangement of the sensor head 2 of the safety switch 1.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a non-contact safety switch. [Background technology]

[0002] Conventionally, a safety switch is provided at the entrance of a room in which industrial machinery, etc. are installed. When the entrance door is closed, the safety switch detects the door closure, which enables the supply of power to the industrial machinery, etc. On the other hand, when the entrance door is opened, the supply of power to the industrial machinery, etc. is disabled.

[0003] As one of the above safety switches, an RFID type non-contact safety switch is used. In this non-contact safety switch, for example, a sensor head having an RFID reader is attached to the periphery of the entrance to a room, and an actuator having an RFID tag is attached to the door. Then, when the entrance is closed by the door and the actuator approaches the sensor head, the code information stored in the RFID tag is read by the RFID reader, making it possible to supply power to industrial machinery, etc.

[0004] In such a non-contact safety switch, the direction in which the actuator approaches the sensor head varies depending on the object on which the non-contact safety switch is attached and the installation position. Therefore, the detection range of the sensor head needs to be able to accommodate the various approach directions of the actuator. However, if an RFID reader and RFID tag that use a low frequency (LF) band are used to expand the detection range of the sensor head, the manufacturing cost of the non-contact safety switch increases. Furthermore, if the antenna area of ​​the RFID reader is increased to expand the detection range, the sensor head becomes larger.

[0005] Therefore, Patent Document 1 proposes a technique for changing the orientation of an RFID reader in an RFID-type safety switch. Specifically, in a switching unit 2 attached to the wall of an entrance, a square-prism-shaped head 8 with a first communication element 6 (i.e., an antenna) provided on one side is attached to the upper end of a square-prism-shaped case 4. Then, the head 8 rotates about a rotation axis facing in the up-down direction, changing the orientation of the first communication element 6 and changing the direction in which the operation unit 3 having the second communication element 7 can be detected. This makes it possible to use the safety switch whether the door to which the operation unit 3 is attached is a right-opening door or a left-opening door. Patent Document 2 also discloses a safety switch with a similar structure.

[0006] In addition, in the RFID-type safety switch 1 shown in Patent Document 3, an antenna At of an RFID reader is attached to the upper end of a square-prism-shaped head part 20 of a switch main body 2 to be attached to a wall in a state in which the antenna At is held by an antenna holder 25. The antenna holder 25 is a gate-shaped member consisting of a rectangular plate-shaped holding part 25A that holds the antenna At, and a pair of rectangular plate-shaped legs 25B, 25C that extend perpendicularly to the main surface of the holding part 25A from both longitudinal ends of the holding part 25A. The legs 25B, 25C extend along a pair of side surfaces of the head part 20, and the free ends of the legs 25B, 25C are attached to the pair of side surfaces by a pair of pins 26 that extend parallel to the longitudinal direction. The antenna holder 25 is rotatable with respect to the head part 20 around a rotation axis that extends in the longitudinal direction through the pair of pins 26. By rotating the antenna holder 25, the antenna At moves between a position facing the upper surface of the head portion 20 and a position facing one side surface of the head portion 20 that is different from the pair of side surfaces. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6600317 [Patent Document 2] Patent No. 6539674 [Patent Document 3] Patent Publication No. 2021-028901 Summary of the Invention [Problem to be solved by the invention]

[0008] Incidentally, in the safety switch of Patent Document 1, the head 8 provided with the first communication element 6 (i.e., antenna) and the case 4 to which the head 8 is attached are both rectangular prism-shaped, so that the switching unit 2 is large and possible mounting positions on a wall or the like are limited. The same is true in Patent Document 2.

[0009] In the safety switch of Patent Document 3, since the head portion 20 is a square prism, the switch body 2 is relatively large, and the possible mounting position on a wall or the like may be limited. In addition, since the antenna holder 25 is gate-shaped and the rotation axis is relatively far away from the holding portion 25A that holds the antenna At, there is a limit to improving the freedom of arrangement of the antenna At due to interference between the holding portion 25A and the head portion 20, etc. For example, it is difficult to arrange the antenna At in the gap between the frame that forms the periphery of the entrance and the door in a closed state. In other words, in this safety switch, there is a limit to the arrangement of the antenna At corresponding to various approach directions of the actuator.

[0010] The present invention has been made in consideration of the above-mentioned problems, and has an object to improve the degree of freedom in the arrangement of a sensor head of a non-contact safety switch. [Means for solving the problem]

[0011] A first aspect of the present invention is a non-contact safety switch comprising an actuator having an RFID tag, and a sensor head having an RFID reader that reads code information stored in the RFID tag when the actuator approaches. The sensor head comprises a head body having a control unit for the RFID reader, and a flat antenna part having an antenna for the RFID reader and connected to the head body so as to be displaceable. The antenna part is connected to the head body via a rotation shaft that extends linearly along an edge of the antenna part, and displaces relative to the head body by rotating about the rotation shaft.

[0012] A second aspect of the present invention is the non-contact safety switch of the first aspect, wherein the head body is also flat, and the rotation shaft is disposed along an edge of the head body.

[0013] A third aspect of the present invention is the non-contact safety switch of the second aspect, wherein the antenna portion can be arranged on the head body in an overlapping state with main surfaces facing each other.

[0014] A fourth aspect of the present invention is the non-contact safety switch of the third aspect, wherein a through hole is provided penetrating the antenna portion and the head body in a thickness direction. The sensor head is attached to an object by a mounting fixture inserted into the through hole.

[0015] A fifth aspect of the present invention is a non-contact safety switch according to the third aspect (which may be either third or fourth aspect), wherein the rotation angle of the antenna part relative to the head body around the rotation axis is defined as 0° when the antenna part overlaps the head body, and the rotation angle increases as the antenna part rotates around the rotation axis and moves away from the head body, and the rotation angle can be changed within a range of 0° or more and 90° or less.

[0016] A sixth aspect of the present invention is a non-contact safety switch of the first aspect (which may be either first or second aspect), wherein the rotation angle of the antenna part relative to the head body around the rotation axis is defined as 0° when the antenna part overlaps the head body, and the rotation angle increases as the antenna part rotates around the rotation axis and moves away from the head body, and the rotation angle can be changed within a range of 90° or more and 270° or less.

[0017] A seventh aspect of the present invention is the non-contact safety switch of the sixth aspect, wherein the antenna portion is provided with a first through hole and a second through hole, each penetrating from a first main surface to a second main surface of the antenna portion. The first through hole has a tapered portion that becomes smaller from the second main surface to the first main surface. The second through hole has a tapered portion that becomes smaller from the first main surface to the second main surface.

[0018] An eighth aspect of the present invention is a non-contact safety switch comprising an actuator having an RFID tag and a sensor head having an RFID reader that reads code information stored in the RFID tag when the actuator approaches. The sensor head comprises a head body having a control unit of the RFID reader, and a flat antenna unit having an antenna of the RFID reader and rotatably connected to the head body. The head body is attached to a first surface of an object. The antenna unit is rotatable between a second position where it is attached to a second surface that extends at an angle relative to the first surface of the object, a first position where it is attached to the first surface of the object via the head body, or a third position where it is attached to a third surface that extends at an angle relative to the first surface of the object at a position different from the second surface.

[0019] A ninth aspect of the present invention is the non-contact safety switch of any one of the first to eighth aspects, wherein the actuator is disposed entirely within an object to which the actuator is attached. Effect of the Invention

[0020] According to the present invention, the degree of freedom in arranging the sensor head can be improved. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a plan view showing a safety switch according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view showing a sensor head. [Diagram 3] FIG. [Figure 4] FIG. 2 is a plan view showing a sensor head. [Diagram 5] FIG. 2 is a perspective view showing a sensor head. [Figure 6] FIG. 11 is a plan view showing a safety switch according to a second embodiment. [Figure 7] FIG. 2 is a perspective view showing a sensor head. [Figure 8] FIG. 2 is a plan view showing a sensor head. [Figure 9] FIG. 2 is a perspective view showing a sensor head. [Figure 10] FIG. 2 is a perspective view showing a sensor head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] FIG. 1 is a plan view showing an RFID (Radio Frequency Identification) type non-contact safety switch 1 according to a first embodiment of the present invention. The safety switch 1 includes a sensor head 2 and an actuator 3. FIG. 2 is a perspective view showing the sensor head 2 of the non-contact safety switch 1. FIG. 3 is a perspective view showing the actuator 3 of the non-contact safety switch 1. In FIG. 1 and FIG. 2, frames 9a and 9b, which are objects to which the non-contact safety switch 1 (hereinafter also simply referred to as the "safety switch 1") is attached, are also shown (similarly in FIG. 4 to FIG. 10). The frames 9a and 9b are so-called aluminum frames made of, for example, an aluminum alloy. The material and shape of the frames 9a and 9b may be variously changed.

[0023] In Fig. 1 to Fig. 3, three mutually orthogonal directions are indicated by arrows as the X direction, the Y direction, and the Z direction. In the example shown in Fig. 1 to Fig. 3, the X direction and the Y direction are horizontal directions perpendicular to each other, and the Z direction is a vertical direction (i.e., an up-down direction). Note that the X direction, the Y direction, and the Z direction are merely for convenience. Therefore, when the safety switch 1 is actually used, the X direction and the Y direction do not need to be horizontal directions, and the Z direction does not need to be a vertical direction (i.e., the direction of gravity). The same is true for the other figures.

[0024] The safety switch 1 is a switch electrically connected to an industrial machine installed in a specific room. The safety switch 1 is typically attached to an entrance of the room. For example, the sensor head 2 of the safety switch 1 is attached to a wall (i.e., a fixed part) that forms the entrance of the room, and the actuator 3 is attached to a door (i.e., a movable part) provided at the entrance.

[0025] In the example shown in Figures 1 and 2, the frame 9a to which the sensor head 2 is attached is part of the edge of the wall that forms the entrance (i.e., part of the periphery of the entrance). Also, the frame 9b to which the actuator 3 is attached is part of the edge of the door. In the state shown in Figure 1, the frame 9b is disposed adjacent to the (+X) side of the frame 9a. The state shown in Figure 1 is a state in which the entrance is closed by the door described above.

[0026] Each of the frames 9a and 9b is a substantially rectangular prism-shaped member extending substantially parallel to the Z direction. The outer shape of each of the frames 9a and 9b in a plan view is substantially square. When the outer surface of the frame 9a has recesses such as grooves and notches and relatively small protrusions, the outer shape of the frame 9a in a plan view refers to the shape of an area surrounded by the outer surface in a plan view when the recesses and protrusions are ignored.

[0027] When the entrance is closed by the door, the actuator 3 approaches the sensor head 2, and the distance between the actuator 3 and the sensor head 2 becomes equal to or less than a predetermined distance (i.e., the communication distance), the RFID reader 205 (described later) of the sensor head 2 reads code information previously stored in the RFID tag 32 (described later) of the actuator 3. In this embodiment, the frequency used for communication between the RFID reader 205 and the RFID tag 32 is in the HF (High Frequency) band. This makes it possible to reduce the manufacturing cost of the safety switch 1 compared to the case where an RFID reader and an RFID tag using a frequency in the LF (Low Frequency) band are used.

[0028] The code information read by the RFID reader 205 is collated with the code information pre-stored in the sensor head 2. If the two pieces of code information match, information that the door is closed (hereinafter also referred to as "door closed information") is output from the sensor head 2, and power can be supplied to the above-mentioned industrial machine. That is, the actuator 3 is detected by the sensor head 2, and power can be supplied to the industrial machine. On the other hand, when the entrance door is open and the actuator 3 is farther away from the sensor head 2 than the communication distance (for example, several centimeters), the door closed information is not output from the sensor head 2, and power cannot be supplied to the industrial machine.

[0029] The actuator 3 illustrated in FIG. 3 is a substantially rectangular prism-shaped member extending in the Z direction. The actuator 3 includes an actuator body 31 and an RFID tag 32. The actuator body 31 is a substantially rectangular prism-shaped member extending in the Z direction, and is formed of, for example, resin. The RFID tag 32 is a substantially flat plate-shaped member having a pair of main surfaces substantially perpendicular to the X direction. The RFID tag 32 is a member in which an inlet (i.e., an antenna, an IC chip, etc.) (not shown) is sealed inside a resin plate that is an exterior body. In this embodiment, the RFID tag 32 is a passive type tag that does not have a battery. The RFID tag is also called an RF tag or an IC tag.

[0030] The RFID tag 32 is, for example, disposed in a recess provided on the side surface of the actuator body 31 on the (+X) side, and is built into the actuator body 31 by filling the recess with resin or the like. The arrangement of the RFID tag 32 in the actuator 3 and the method of fixing the RFID tag 32 to the actuator body 31 may be changed in various ways. For example, the RFID tag 32 may be bonded to the side surface of the actuator body 31 on the (-X) side (i.e., the side surface facing the frame 9a in the X direction) via an adhesive or the like. Alternatively, the inlet of the RFID tag 32 may be disposed in the recess of the actuator body 31, and the recess may be filled with resin or the like.

[0031] The sensor head 2 includes a head body 21 and an antenna unit 22. The head body 21 is a substantially flat plate-like member extending substantially perpendicularly to the Y direction. The shape of the head body 21 in a front view (i.e., the shape when viewed parallel to the Y direction) is a substantially rectangular shape elongated in the Z direction. In the following description, the main surface of the head body 21 on the (-Y) side in FIG. 1 is also referred to as the "first main surface 211," and the main surface on the (+Y) side in FIG. 1 is also referred to as the "second main surface 212." The head body 21 is fixed to the frame 9a in a state in which the substantially planar second main surface 212 faces the outer surface 91 on the (-Y) side of the frame 9a. In the example shown in FIG. 1, the second main surface 212 of the head body 21 is in contact with the outer surface 91 of the frame 9a.

[0032] The head body 21 has an IC chip or the like which is the control unit 215 of the RFID reader 205. The head body 21 is, for example, a member in which the control unit 215 is sealed inside a resin plate which is an exterior body. In other words, the control unit 215 is disposed between the first main surface 211 and the second main surface 212 of the head body 21. In the example shown in FIG. 2, the control unit 215 is depicted by a dashed line as a substantially flat plate-like part extending substantially perpendicularly to the Y direction. A cable 24 for supplying power to the control unit 215 is connected to the lower end of the head body 21. The cable 24 extends downward from the lower end of the head body 21. Note that, for convenience of illustration, FIG. 2 illustrates only the vicinity of the connection part with the head body 21 of the cable 24 (similar to FIG. 5).

[0033] An indicator 23 is provided on the lower part of the first main surface 211 of the head body 21. In the example shown in FIG. 2, the indicator 23 has a substantially polygonal shape when viewed from the front. The shape of the indicator 23 may be changed in various ways. When the actuator 3 is detected by the sensor head 2, for example, a light source such as an LED (not shown) provided inside the head body 21 lights up in green, and the light from the light source passes through the indicator 23 and becomes visible. On the other hand, when the actuator 3 is not detected by the sensor head 2, the light source lights up in red. By visually checking the state (color in the above example) of the indicator 23, the worker can easily confirm whether or not power is supplied to the industrial machine. The combination of the detection state of the actuator 3 by the sensor head 2 and the light color or the presence or absence of the light source indicating the state may be changed in various ways.

[0034] The head body 21 is provided with two through holes 213 aligned in the Z direction. Each through hole 213 penetrates the head body 21 in the Y direction (i.e., the thickness direction of the head body 21). In other words, each through hole 213 penetrates the head body 21 from the first main surface 211 to the second main surface 212. In a front view of the head body 21, the shape of each through hole 213 is a substantially elliptical shape that is long in the X direction. The two through holes 213 are disposed on the (+Z) side and the (-Z) side (i.e., the upper side and the lower side) of the control unit 215. The head body 21 is attached to the frame 9a by two screws 41 inserted into the two through holes 213, respectively. The shape of the through holes 213 in a front view may be changed in various ways.

[0035] The antenna unit 22 is a substantially flat plate-like member extending substantially perpendicularly to the X direction. The shape of the antenna unit 22 in a front view (i.e., the shape when viewed parallel to the X direction) is a substantially rectangular shape elongated in the Z direction. The length of the antenna unit 22 in the Z direction is smaller than the length of the head body 21 in the Z direction. In the following description, the main surface of the antenna unit 22 on the (-X) side in FIG. 1 is also referred to as the "first main surface 221," and the main surface on the (+X) side in FIG. 1 is also referred to as the "second main surface 222." The antenna unit 22 is fixed to the frame 9a with the substantially planar first main surface 221 facing the outer surface 92 on the (+X) side of the frame 9a. In the example shown in FIG. 1, the first main surface 221 of the antenna unit 22 is in contact with the outer surface 92 of the frame 9a.

[0036] The antenna unit 22 has an antenna 225 of the RFID reader 205. In this embodiment, the antenna 225 is a directional antenna having directionality. The antenna unit 22 is, for example, a member in which the antenna 225 is sealed inside a resin plate that is an exterior body. In other words, the antenna 225 is disposed between the first main surface 221 and the second main surface 222 of the antenna unit 22. In the example shown in FIG. 2, the antenna 225 is depicted by a dashed line as a substantially flat plate-shaped part that extends substantially perpendicularly to the X direction. The antenna 225 is electrically connected to the control unit 215 of the head main body 21 via an electric wire (not shown). This constitutes the above-mentioned RFID reader 205.

[0037] The (-Y) end of the antenna part 22 is connected to the (+X) end of the head body 21. Specifically, a rotation axis J1 is provided near the edge of the (-Y) side of the antenna part 22, and extends linearly along the edge approximately parallel to the Z direction. The rotation axis J1 is disposed near the edge of the (+X) side of the head body 21, and extends along the edge. In the example shown in FIG. 1, the rotation axis J1 is located slightly on the (+Y) side of the second main surface 212 of the head body 21, and is located at approximately the same position as the antenna part 22 in the X direction. The antenna part 22 is connected to the head body 21 via the rotation axis J1, and is displaced relative to the head body 21 by rotating about the rotation axis J1.

[0038] At the connection portion between the antenna portion 22 and the head body 21, for example, a pair of protrusions protruding upward and downward from the end portion on the (-Y) side of the antenna portion 22 are provided. Also, a pair of recesses into which the pair of protrusions are inserted are provided at the upper and lower ends of the end portion on the (+X) side of the head body 21. Then, the pair of protrusions of the antenna portion 22 are inserted into the pair of recesses of the head body 21 and rotatably supported, thereby forming the above-mentioned rotation axis J1 facing in the up-down direction, and the antenna portion 22 is connected to the head body 21 so as to be displaceable.

[0039] The antenna unit 22 is provided with two through holes 223 aligned in the Z direction. Each through hole 223 penetrates the antenna unit 22 in the X direction (i.e., the thickness direction of the antenna unit 22). In other words, each through hole 223 penetrates the antenna unit 22 from the first main surface 221 to the second main surface 222. In a front view of the antenna unit 22, the shape of each through hole 223 is a substantially elliptical shape that is long in the Y direction. The two through holes 223 are disposed on the (+Z) side and the (-Z) side (i.e., the upper side and the lower side) of the antenna 225. The antenna unit 22 is attached to the frame 9a by two screws 43 inserted into the two through holes 223, respectively. The shape of the through holes 223 in a front view may be changed in various ways.

[0040] As described above, the frame 9a is a member having a substantially rectangular prism shape. An opening 95 (i.e., a slit extending in the Z direction) extending in the vertical direction is provided in the center of the width direction (i.e., the X direction) on the outer side surface 91 on the (-Y) side of the frame 9a, and the opening 95 extends in the vertical direction over substantially the entire length of the outer side surface 91 in the vertical direction. In addition, a groove portion 96 that is wider in the X direction than the opening 95 and extends in the vertical direction is provided on the (+Y) side of the opening 95, and extends in the vertical direction over substantially the entire length of the frame 9a in the vertical direction. The groove portion 96 is located on the inside of the frame 9a relative to the opening 95 between the opening 95 and the central axis of the frame 9a (i.e., a virtual straight line that is located at the center of the frame 9a in a plan view and extends in the vertical direction). In other words, the groove portion 96 is an internal space of the frame 9a that penetrates the frame 9a in the vertical direction.

[0041] In the frame 9a, the shape of each of the outer side surfaces 92-94 and the structure inside each of the outer side surfaces 92-94 of the (+X) side outer side surface 92, the (-X) side outer side surface 93, and the (+Y) side outer side surface 94 are substantially similar to that of the outer side surface 91 on the (-Y) side. That is, an opening 95 is provided in the center of the width direction (i.e., Y direction) of the outer side surface 92, and a groove portion 96 is provided on the (-X) side of the opening 95. Also, an opening 95 is provided in the center of the width direction (i.e., Y direction) of the outer side surface 93, and a groove portion 96 is provided on the (+X) side of the opening 95. An opening 95 is provided in the center of the width direction (i.e., X direction) of the outer side surface 94, and a groove portion 96 is provided on the (-Y) side of the opening 95.

[0042] As described above, the head body 21 is attached to the outer side surface 91 on the (-Y) side of the frame 9a by the two screws 41, which are mounting fixtures. Each screw 41 is inserted from the (-Y) side of the head body 21 (i.e., from the first main surface 211 side) through the through hole 213 of the head body 21 and the opening 95 of the outer side surface 91 to the groove portion 96, and is screwed into the nut 42 arranged in the groove portion 96. The nut 42 is a nut for the frame 9a, and has a shape that makes it easy to arrange in the groove portion 96. The width of the nut 42 in the X direction is larger than the width of the opening 95 of the outer side surface 91 in the X direction. The two screws 41 are tightened, and the head body 21 and the nut 42 sandwich a portion near the outer side surface 91 of the frame 9a, so that the head body 21 is fixed to the frame 9a. In the example shown in FIG. 1 and FIG. 2, the screw 41 is a round screw with a screw head that is approximately hemispherical. The type of the screw 41 may be changed in various ways.

[0043] As described above, the antenna unit 22 is attached to the outer surface 92 on the (+X) side of the frame 9a by the two screws 43, which are mounting fixtures. Each screw 43 is inserted from the (+X) side of the antenna unit 22 (i.e., from the second main surface 222 side) through the through hole 223 of the antenna unit 22 and the opening 95 of the outer surface 92 to the groove 96, and is screwed into the nut 42 arranged in the groove 96. The width of the nut 42 in the Y direction is larger than the width of the opening 95 of the outer surface 92 in the Y direction. The two screws 43 are tightened, and the antenna unit 22 and the nut 42 sandwich a portion near the outer surface 92 of the frame 9a, thereby fixing the antenna unit 22 to the frame 9a. The screw 43 is a countersunk screw with a top of the screw head (i.e., the end on the (+X) side) that is approximately flat. The type of the screw 43 may be changed in various ways.

[0044] 1 and 2, the area of ​​each through hole 223 of the antenna section 22 gradually decreases from the second main surface 222 toward the first main surface 221. In other words, each through hole 223 has a tapered portion 224 that becomes smaller from the second main surface 222 toward the first main surface 221. In other words, the opening of the through hole 223 in the second main surface 222 is larger than the opening of the through hole 223 in the first main surface 221. The tapered portion 224 is provided, for example, over substantially the entire through hole 223 in the X direction.

[0045] As described above, the screw 43 is a flat head screw, and the screw head of the screw 43 is housed inside the through hole 223 with the side surface of the screw head in contact with the tapered portion 224 of the through hole 223. This makes it possible to reduce the space in the X direction between the frames 9a and 9b required to attach the antenna unit 22 to the frame 9a. As a result, when the entrance is closed by the door described above, it is possible to reduce the gap in the X direction between the frames 9a and 9b.

[0046] 1, the top of the screw head of the screw 43 is also located inside the through hole 223. That is, the entire screw head of the screw 43 is located on the (-X) side of the second main surface 222 of the antenna unit 22, and does not protrude on the (+X) side of the second main surface 222. This makes it possible to further reduce the space in the X direction between the frames 9a and 9b required to attach the antenna unit 22 to the frame 9a. As a result, when the entrance is closed by the above-mentioned door, the gap in the X direction between the frames 9a and 9b can be further reduced.

[0047] In the through hole 223 of the antenna unit 22, the tapered portion 224 does not necessarily need to be provided over the entire X direction of the through hole 223, and may be provided only in a part of the X direction of the through hole 223 from the second main surface 222 of the antenna unit 22 toward the (-X) direction. Alternatively, the tapered portion 224 may be omitted.

[0048] As described above, the actuator 3 is fixed to the frame 9b. The shape of the frame 9b is substantially the same as that of the frame 9a described above. In the example shown in FIG. 1, the actuator 3 is disposed in the internal space of the groove 96 on the (-X) side (i.e., the groove 96 located closest to the frame 9a) among the four grooves 96 of the frame 9b. The actuator 3 is fixed to the frame 9b by the screw 45 with the (-X) side surface of the actuator body 31 in contact with the inner surface of the (-X) side of the groove 96.

[0049] The screw 45 is inserted from the (-X) side through the opening 95 into a through hole penetrating the actuator body 31 in the X direction, and is screwed into a nut 46 provided on the actuator body 31. The tip of the screw 45 on the (+X) side is pressed against the inner surface of the groove 96 on the (+X) side. This biases the actuator body 31 against the inner surface of the groove 96 on the (-X) side, and the actuator 3 is fixed to the frame 9b. The screw 45 is, for example, a set screw without a screw head. The type of the screw 45 may be changed in various ways.

[0050] In the example shown in FIG. 1, the actuator 3 is entirely disposed inside the outer shape of the frame 9b in a plan view. In other words, the actuator 3 is entirely disposed inside the frame 9b. Therefore, it is possible to eliminate the need for a space between the frames 9a and 9b for attaching the actuator 3 to the frame 9b. As a result, it is possible to reduce the gap in the X direction between the frames 9a and 9b when the entrance is closed by the door. Also, in the example shown in FIG. 1, the tip of the screw 45 on the (-X) side is located in the opening 95, and does not protrude beyond the outer surface of the (-X) side of the frame 9b on the (-X) side. This makes it possible to further reduce the gap in the X direction between the frames 9a and 9b when the entrance is closed by the door.

[0051] In the state shown in FIG. 1, the head body 21 and the antenna portion 22 in the sensor head 2 are disposed so as to be substantially perpendicular to each other in a plan view. In other words, the angle θ between the second main surface 212 of the head body 21 and the first main surface 221 of the antenna portion 22 in a plan view is approximately 90°. The angle θ is a rotation angle of the antenna portion 22 with respect to the head body 21 about the rotation axis J1 in a plan view, and is hereinafter also referred to as the "rotation angle θ". The rotation angle θ increases as the antenna portion 22 rotates about the rotation axis J1 in the clockwise direction in FIG. 1 and moves away from the head body 21 (i.e., the first main surface 221 of the antenna portion 22 moves away from the second main surface 212 of the head body 21 in the circumferential direction about the rotation axis J1).

[0052] As described above, the antenna unit 22 is connected to the head body 21 so as to be rotatable about the rotation axis J1. In the example shown in FIG. 1, the rotation angle θ can be changed within a range of 0° or more and 180° or less. The rotation angle θ is changed, for example, according to the shape of the frame 9a to which the sensor head 2 is attached. When the outer shape of the frame 9a in a plan view is, for example, a substantially equilateral triangle, the rotation angle θ is set to about 60°. In this case, the head body 21 is attached to one outer surface of the frame 9a, and the antenna unit 22 is attached to another outer surface that is inclined at an inclination angle of about 60° in a plan view with respect to the one outer surface and spreads out laterally from the one outer surface.

[0053] Furthermore, when the outer shape of the frame 9a in plan view is, for example, a substantially regular hexagon, the rotation angle θ is set to about 120°. In this case, the head body 21 is attached to one outer surface of the frame 9a, and the antenna unit 22 is attached to another outer surface that is inclined at an inclination angle of about 120° in plan view with respect to the one outer surface and spreads out laterally from the one outer surface.

[0054] The range in which the rotation angle θ can be changed does not necessarily have to be 0° or more and 180° or less, and may be changed in various ways. For example, the rotation angle θ may be changeable within a range of 0° or more and 90° or less.

[0055] In the sensor head 2, the rotation angle θ can be set to 0°, and the antenna section 22 can be stacked on the head body 21, as shown in Figures 4 and 5. In the state shown in Figures 4 and 5, the antenna section 22 and the head body 21 are stacked in the thickness direction (i.e., the Y direction) of the antenna section 22 and the head body 21. The first main surface 221 of the antenna section 22 and the second main surface 212 of the head body 21 face each other in the Y direction and are in direct contact with each other without any other member interposed therebetween.

[0056] The sensor head 2 is fixed to the frame 9a by two flat head screws 43 in a state where the first main surface 211 of the head body 21 faces the outer surface 91 on the (-Y) side of the frame 9a. In the example shown in FIG. 4, the first main surface 211 of the head body 21 is in contact with the outer surface 91 of the frame 9a. In the sensor head 2 in the state shown in FIG. 4, the through hole 223 of the antenna unit 22 and the through hole 213 of the head body 21 overlap in the Y direction, forming a through hole penetrating the sensor head 2 in the thickness direction (i.e., the Y direction). The screw 43, which is a mounting tool, is inserted into the through hole 223 of the antenna unit 22 from the (-Y) side of the antenna unit 22, and is inserted into the groove portion 96 through the through hole 223 of the antenna unit 22, the through hole 213 of the head body 21, and the opening 95 of the outer surface 91 of the frame 9a. The screw 43 is screwed into the nut 42 arranged in the groove portion 96. The two screws 43 are tightened, and the head body 21 and the nut 42 sandwich a portion of the frame 9a near the outer surface 91 thereof, whereby the sensor head 2 is fixed to the frame 9a.

[0057] 4 and 5, the actuator 3 (see FIG. 1) is disposed close to the (-Y) side of the sensor head 2, and when the actuator 3 faces the antenna unit 22 of the sensor head 2 in the Y direction at a distance equal to or less than the communication distance, the sensor head 2 detects the actuator 3. Then, the above-mentioned door closure information is output from the sensor head 2, making it possible to supply power to the industrial machine.

[0058] As described above, the screw 43 is a countersunk screw, and the screw head of the screw 43 is housed inside the through hole 223 while the side of the screw head is in contact with the tapered portion 224 of the through hole 223 of the antenna unit 22. In the example shown in FIG. 4, the top of the screw head of the screw 43 is also located inside the through hole 223. That is, the entire screw head of the screw 43 is located on the (+Y) side of the second main surface 222 of the antenna unit 22, and does not protrude on the (-Y) side of the second main surface 222. This makes it possible to reduce the space in the Y direction required to attach the sensor head 2 to the frame 9a between the frame 9a and the frame 9b to which the actuator 3 is attached. As a result, it is possible to reduce the gap in the Y direction between the frame 9a and the frame 9b when the entrance is closed by the door described above.

[0059] The lower part of the head body 21 extends downward (i.e., toward the (-Z) side) from the lower end of the antenna part 22. An indicator 23 having approximately the same shape as that provided on the first main surface 211 is provided on the lower part of the second main surface 212 of the head body 21. When the actuator 3 is detected by the sensor head 2, for example, a light source such as an LED (not shown) provided inside the head body 21 lights up in green, and the light from the light source passes through the indicator 23 and becomes visible. On the other hand, when the actuator 3 is not detected by the sensor head 2, the light source lights up in red. By visually checking the state (color in the above example) of the indicator 23, the worker can easily confirm whether power is being supplied to the industrial machine or not.

[0060] As described above, the safety switch 1 includes the actuator 3 and the sensor head 2. The actuator 3 includes the RFID tag 32. The sensor head 2 includes the RFID reader 205 that reads the code information stored in the RFID tag 32 when the actuator 3 approaches. The sensor head 2 includes the head body 21 and the antenna unit 22. The head body 21 includes the control unit 215 of the RFID reader 205. The antenna unit 22 includes the antenna 225 of the RFID reader 205. The antenna unit 22 is a flat plate-shaped member that is displaceably connected to the head body 21. The antenna unit 22 is connected to the head body 21 via the rotation axis J1 that extends linearly along the edge of the antenna unit 22. The antenna unit 22 is displaced relative to the head body 21 by rotating about the rotation axis J1.

[0061] This improves the degree of freedom in arranging the antenna unit 22 and the head body 21 (i.e., the degree of freedom in arranging the sensor head 2) when attaching the sensor head 2 to the target object (the frame 9a in the above example). For example, as shown in FIG. 1, only the antenna unit 22 can be arranged in a narrow gap between the frames 9a and 9b, and the head body 21 can be arranged outside the gap. Alternatively, as shown in FIGS. 4 and 5, the antenna unit 22 and the head body 21 can be arranged only on one outer surface 91 of the frame 9a. As a result, the sensor head 2 can accommodate various approach directions of the actuator 3 while suppressing an increase in size of the antenna unit 22.

[0062] As described above, the head body 21 is also preferably flat, and the rotation axis J1 is disposed so as to extend along the edge of the head body 21. This makes it possible to reduce the size of the sensor head 2. As a result, the degree of freedom in arranging the sensor head 2 can be further improved.

[0063] As described above, it is preferable that the antenna portion 22 can be arranged on the head body 21 with the main surfaces (i.e., the first main surface 221 of the antenna portion 22 and the second main surface 212 of the head body 21) facing each other and overlapping with each other. This makes it possible to reduce the area required for mounting the sensor head 2 on the target object (the frame 9a in the above example).

[0064] As described above, in a state where the antenna unit 22 and the head body 21 overlap, it is preferable to provide a through hole (i.e., the through hole 223 of the antenna unit 22 and the through hole 213 of the head body 21) that penetrates the antenna unit 22 and the head body 21 in the thickness direction. The sensor head 2 is attached to the target object by a mounting fixture (screw 43 in the above example) that is inserted into the through hole. In this way, by using the mounting fixture used to mount the antenna unit 22 also to mount the head body 21, it is possible to easily mount the antenna unit 22 and the head body 21 to the target object.

[0065] As described above, regarding the rotation angle θ of the antenna part 22 with respect to the head body 21 about the rotation axis J1, if the state in which the antenna part 22 overlaps the head body 21 is defined as 0°, and the rotation angle θ increases as the antenna part 22 rotates about the rotation axis J1 and moves away from the head body 21, it is preferable that the rotation angle θ be changeable within a range of 0° or more and 90° or less. This can improve the degree of freedom in the manner in which the safety switch 1 is attached to the target object (frames 9a, 9b in the above example). This structure of the safety switch 1 is particularly suitable when the safety switch 1 is attached to a target object having a substantially rectangular prism shape.

[0066] As described above, it is preferable that the entire actuator 3 is disposed inside the object to which the actuator 3 is attached (in the above example, the frame 9b). This makes it possible to reduce the space between the object to which the actuator 3 is attached and the object to which the sensor head 2 is attached. In addition, it is possible to prevent the actuator 3 from colliding with other structures when the object to which the actuator 3 is attached moves (for example, when a door is opened or closed).

[0067] In the frame 9a, which is the object to which the sensor head 2 is attached, the outer surface 91 on the (-Y) side and the outer surface 92 on the (+X) side are called the "first surface" and the "second surface", respectively. The second surface extends laterally from the first surface while being inclined at an inclination angle of 90° with respect to the first surface in a plan view. In the state shown in Figs. 1 and 2, the head main body 21 is attached to the first surface of the object, and the antenna unit 22 is attached to the second surface of the object. Also, in the state shown in Figs. 3 and 4, the head main body 21 remains attached to the first surface of the object, and the antenna unit 22 is attached to the first surface via the head main body 21.

[0068] Thus, in the safety switch 1, the head body 21 is attached to a first surface of the object, and the antenna unit 22 is rotatable between a second position where it is attached to a second surface that expands while inclining relative to the first surface of the object, and a first position where it is attached to the first surface of the object via the head body 21. This makes it possible to improve the degree of freedom in the arrangement of the antenna unit 22 and the head body 21 (i.e., the degree of freedom in the arrangement of the sensor head 2) when attaching the sensor head 2 to the object, as described above.

[0069] Next, an RFID-type non-contact safety switch 1a (hereinafter also simply referred to as "safety switch 1a") according to a second embodiment of the present invention will be described. Fig. 6 is a plan view showing the safety switch 1a. Fig. 7 is a perspective view showing a sensor head 2a of the safety switch 1a. The safety switch 1a includes a sensor head 2a having a different structure from the sensor head 2 shown in Figs. 1 and 2, and the actuator 3 described above. The sensor head 2a is attached to the frame 9a described above, and the actuator 3 is attached to the frame 9b described above.

[0070] In the safety switch 1a, the actuator 3 is disposed close to the (+X) side of the sensor head 2a, and when the actuator 3 faces the antenna part 22a of the sensor head 2a in the X direction at a distance equal to or less than the communication distance, the sensor head 2a detects the actuator 3. Then, the above-mentioned door closing information is output from the sensor head 2a, making it possible to supply power to the industrial machine.

[0071] The sensor head 2a includes a head body 21a and an antenna portion 22a. The head body 21a is a substantially flat plate-like member extending substantially perpendicularly to the Y direction, similar to the head body 21 described above (see FIGS. 1 and 2). The shape of the head body 21a in a front view (i.e., the shape when viewed parallel to the Y direction) is a substantially rectangular shape elongated in the Z direction. The width of the head body 21a in the X direction is slightly larger than the width of the head body 21 in the X direction. The length of the head body 21a in the Z direction is shorter than the length of the head body 21 in the Z direction.

[0072] The head body 21a is fixed to the frame 9a with the substantially planar second main surface 212a on the (+Y) side facing the outer side surface 91 on the (-Y) side of the frame 9a. In the example shown in Fig. 6, the second main surface 212a of the head body 21a is in contact with the outer side surface 91 of the frame 9a. As with the head body 21, the head body 21a is fixed to the frame 9a by two screws 41 inserted into two through holes 213a of the head body 21a and a nut 42 disposed in a groove portion 96 of the frame 9a.

[0073] The head body 21a has a control unit 215a of the RFID reader 205a, similar to the head body 21. The type, shape, and arrangement of the control unit 215a are substantially the same as those of the above-mentioned control unit 215. A cable 24a for supplying power to the control unit 215a is connected to the lower end of the head body 21a. The cable 24a extends downward from the end on the (+X) side at the lower end of the head body 21a. For convenience of illustration, FIG. 7 shows only the vicinity of the connection part with the head body 21a of the cable 24a (similar to FIG. 9 and FIG. 10).

[0074] The indicator 23a is provided at the end of the (-X) side of the head body 21a, over approximately the entire length in the Z direction of the head body 21. The indicator 23a, similar to the above-mentioned indicator 23, lights up when the actuator 3 is detected by the sensor head 2a. This allows the worker to easily check whether power is being supplied to the industrial machine.

[0075] The antenna part 22a is a substantially flat plate-shaped member extending substantially perpendicularly to the X direction, substantially similar to the above-mentioned antenna part 22 (see FIG. 1 and FIG. 2). The shape of the antenna part 22 in a front view (i.e., the shape when viewed parallel to the X direction) is a substantially rectangular shape elongated in the Z direction. The width of the antenna part 22a in the X direction is slightly larger than the width of the antenna part 22 in the X direction. The length of the antenna part 22a in the Z direction is substantially the same as the length of the antenna part 22 in the Z direction, and is also substantially the same as the length of the head body 21a in the Z direction. The antenna part 22a is fixed to the frame 9a in a state in which the substantially planar first main surface 221a on the (-X) side faces the outer side surface 92 on the (+X) side of the frame 9a. In the example shown in FIG. 6, the first main surface 221a of the antenna part 22a is in contact with the outer side surface 92 of the frame 9a.

[0076] The antenna unit 22a has an antenna 225a of the RFID reader 205a, similar to the antenna unit 22. The type, shape and arrangement of the antenna 225a are substantially the same as those of the above-mentioned antenna 225. The antenna 225a is electrically connected to the control unit 215a of the head main body 21a via an electric wire (not shown). This constitutes the above-mentioned RFID reader 205a.

[0077] In the sensor head 2a, the end of the antenna part 22a on the (-Y) side is connected to the end of the head body 21a on the (+X) side, similarly to the sensor head 2. The structure of the connection part between the antenna part 22a and the head body 21a is similar to the structure of the connection part between the antenna part 22 and the head body 21 described above. The antenna part 22a is connected to the head body 21a via a rotation axis J1, and is displaced relative to the head body 21a by rotating about the rotation axis J1. In other words, the antenna part 22a is displaceably connected to the head body 21a via the rotation axis J1. The rotation axis J1 is disposed near the edge of the antenna part 22a on the (-Y) side and near the edge of the head body 21a on the (+X) side, and extends linearly along both ends substantially parallel to the Z direction. In the example shown in FIG. 6, the rotation axis J1 is located at substantially the same position as the head body 21a in the Y direction, and is located at substantially the same position as the antenna part 22a in the X direction.

[0078] In the sensor head 2a, a cover 25a is provided to cover the connection between the head body 21a and the antenna unit 22a. The cover 25a is, for example, a substantially sheet-like member formed of a flexible resin, and extends substantially parallel to the Z direction along the connection. The cover 25a is provided on the (+X) side of the head body 21a and on the (-Y) side of the antenna unit 22a, over substantially the entire length of the connection in the Z direction. The cover 25a is detachably attached to the connection. In the sensor head 2a, the connection is covered by the cover 25a, so that the above-mentioned electric wire (not shown) connecting the control unit 215a and the antenna 225a of the RFID reader 205a is prevented from being exposed at the connection. As a result, it is possible to suppress breakage of the electric wire due to contact with another structure or the like.

[0079] The antenna section 22a is provided with two through holes 223a aligned in the Z direction. Each through hole 223a penetrates the antenna section 22a in the X direction (i.e., the thickness direction of the antenna section 22a). In other words, each through hole 223a penetrates the antenna section 22a from the first main surface 221a to the second main surface 222a. In a front view of the antenna section 22a, the shape of each through hole 223a is a substantially elliptical shape that is long in the Y direction. Note that the shape of the through hole 223a in a front view may be changed in various ways. The two through holes 223a are arranged on the (+Z) side and (-Z) side (i.e., the upper side and the lower side) of the antenna 225a.

[0080] In the example shown in Fig. 6 and Fig. 7, the through hole 223a on the (+Z) side has a tapered portion 224a in which the hole becomes smaller from the second main surface 222a to the first main surface 221a of the antenna part 22a. The through hole 223a on the (-Z) side has a tapered portion 224a in which the hole becomes smaller from the first main surface 221a to the second main surface 222a of the antenna part 22a. That is, in the two through holes 223a, the inclination of the inner surface of the tapered portion 224a is in the opposite direction to each other. The tapered portion 224a of each through hole 223a is provided, for example, over substantially the entire through hole 223a in the X direction.

[0081] 6 and 7, the antenna unit 22a is attached to the frame 9a by one screw 43 inserted into the through hole 223a on the (+Z) side. The screw 43 is inserted from the (+X) side of the antenna unit 22a (i.e., from the second main surface 222a side) through the through hole 223a on the (+Z) side of the antenna unit 22a and the opening 95 of the outer surface 92 to the groove 96, and is screwed into the nut 42 arranged in the groove 96. The screw 43 is tightened to sandwich a portion of the frame 9a near the outer surface 92 between the antenna unit 22a and the nut 42, thereby fixing the antenna unit 22a to the frame 9a.

[0082] As described above, the screw 43 is a countersunk head screw with a substantially flat top. The screw head of the screw 43 is housed inside the through hole 223a while the side of the screw head is in contact with the tapered portion 224a of the through hole 223a. This makes it possible to reduce the space in the X direction between the frame 9a and the frame 9b to which the actuator 3 is attached, which is necessary to attach the antenna unit 22a to the frame 9a. As a result, when the entrance is closed by the door, it is possible to reduce the gap in the X direction between the frame 9a and the frame 9b.

[0083] In the example shown in Fig. 6, the top of the screw head of the screw 43 is also located inside the through hole 223a. That is, the entire screw head of the screw 43 is located on the (-X) side of the second main surface 222a of the antenna unit 22a, and does not protrude on the (+X) side of the second main surface 222a. This makes it possible to further reduce the space in the X direction between the frames 9a and 9b required to attach the antenna unit 22a to the frame 9a. As a result, when the entrance is closed by the above-mentioned door, the gap in the X direction between the frames 9a and 9b can be further reduced.

[0084] In addition, in the through hole 223 on the (+Z) side of the antenna portion 22a, the tapered portion 224a does not necessarily need to be provided over the entire X-direction of the through hole 223a, and may be provided only in a part of the X-direction of the through hole 223a from the second main surface 222a of the antenna portion 22a toward the (-X) direction.

[0085] In the state shown in Fig. 6, the rotation angle θ of the antenna part 22a with respect to the head body 21a (i.e., the angle between the second main surface 212a of the head body 21a and the first main surface 221a of the antenna part 22a) is about 90°. The rotation angle θ can be changed, for example, within a range of 90° or more and 270° or less. Figs. 8 and 9 show a state in which the rotation angle θ is set to 270° and the antenna part 22a is attached to the outer surface 93 on the (-X) side of the frame 9a.

[0086] In this case, the head body 21a is turned over from the state shown in FIG. 6 and FIG. 7, and fixed to the frame 9a by two screws 41 with the first main surface 211a of the head body 21a facing the outer surface 91 of the frame 9a on the (-Y) side. The cable 24a extends downward from the end of the head body 21a on the (-X) side at the lower end. The antenna unit 22a is fixed to the frame 9a by one screw 43 with the second main surface 222a facing the outer surface 93 of the frame 9a. In the example shown in FIG. 8, the first main surface 211a of the head body 21a is in contact with the outer surface 91 of the frame 9a, and the second main surface 222a of the antenna unit 22a is in contact with the outer surface 93 of the frame 9a. A cover 25a is provided at the connection between the head body 21a and the antenna unit 22a.

[0087] In the safety switch 1a in the state shown in Figures 8 and 9, the actuator 3 (see Figure 6) is disposed close to the (-X) side of the sensor head 2a, and when it faces the antenna part 22a of the sensor head 2a in the X direction at a distance equal to or less than the communication distance, the sensor head 2a detects the actuator 3. Then, the above-mentioned door closing information is output from the sensor head 2a, and power can be supplied to the industrial machine. The indicator 23a is located at the end of the (+X) side of the head body 21, and lights up when the actuator 3 is detected by the sensor head 2a.

[0088] 9, the screw 43 is inserted into the through hole 223a on the (-Z) side of the antenna unit 22a from the (-X) side (i.e., the first main surface 221a side). The screw 43 is inserted through the through hole 223a and the opening 95 of the outer surface 93 up to the groove 96 and is screwed into the nut 42 arranged in the groove 96. The screw 43 is tightened to sandwich a portion of the frame 9a near the outer surface 93 between the antenna unit 22a and the nut 42, thereby fixing the antenna unit 22a to the frame 9a.

[0089] As described above, the screw 43 is a countersunk screw, and the screw head of the screw 43 is housed inside the through hole 223a while the side surface of the screw head is in contact with the tapered portion 224a of the through hole 223a. In the example shown in FIG. 9, the top of the screw head of the screw 43 is also located inside the through hole 223a. That is, the entire screw head of the screw 43 is located on the (+X) side of the first main surface 221a of the antenna unit 22a, and does not protrude on the (-X) side of the first main surface 221a. This makes it possible to further reduce the space in the X direction between the frames 9a and 9b required to attach the antenna unit 22a to the frame 9a. As a result, it is possible to further reduce the gap in the X direction between the frames 9a and 9b when the entrance is closed by the door.

[0090] As described above, the safety switch 1a includes the actuator 3 and the sensor head 2a, similar to the above-mentioned safety switch 1. The actuator 3 includes an RFID tag 32 (see FIG. 3). The sensor head 2a includes an RFID reader 205a that reads code information stored in the RFID tag 32 when the actuator 3 approaches. The sensor head 2a includes a head body 21a and an antenna unit 22a. The head body 21a includes a control unit 215a of the RFID reader 205a. The antenna unit 22a includes an antenna 225a of the RFID reader 205a. The antenna unit 22a is a flat plate-shaped member displaceably connected to the head body 21a. The antenna unit 22a is connected to the head body 21a via a rotation axis J1 that extends linearly along the edge of the antenna unit 22a. The antenna unit 22a is displaced relative to the head body 21a by rotating about the rotation axis J1.

[0091] As a result, as described above, when attaching the sensor head 2a to the target object (in the above example, the frame 9a), the degree of freedom in arranging the antenna portion 22a and the head body 21a (i.e., the degree of freedom in arranging the sensor head 2a) can be improved. As a result, the sensor head 2a can accommodate various approach directions of the actuator 3 while suppressing an increase in size of the antenna portion 22a.

[0092] As described above, the head body 21a is preferably also flat, and the rotation axis J1 is disposed along the edge of the head body 21a. This allows the sensor head 2a to be made smaller. As a result, the degree of freedom in arranging the sensor head 2a can be further improved.

[0093] As described above, regarding the rotation angle θ of the antenna portion 22a with respect to the head body 21a around the rotation axis J1, if the state in which the antenna portion 22a overlaps the head body 21a is defined as 0°, and the rotation angle θ increases as the antenna portion 22a rotates around the rotation axis J1 and moves away from the head body 21a, it is preferable that the rotation angle θ can be changed within a range of 90° or more and 270° or less.

[0094] This improves the degree of freedom in the manner in which the safety switch 1a is attached to the target object (in the above example, frames 9a and 9b). For example, as shown in Fig. 6 to Fig. 9, while the head body 21a is attached to an outer surface 91 on the (-Y) side of the frame 9a and the cable 24a is maintained in a state extending downward from the lower end of the head body 21a, the antenna section 22a can be selectively attached to one of an outer surface 92 on the (+X) side and an outer surface 93 on the (-X) side of the frame 9a. This structure of the safety switch 1a is particularly suitable for attaching the safety switch 1a to a target object having a substantially rectangular prism shape.

[0095] In the safety switch 1a, if the through holes 223a on the (+Z) side and (-Z) side in Fig. 7 are called the "first through hole" and the "second through hole", respectively, the antenna section 22a is provided with a first through hole and a second through hole that penetrate from the first main surface 221a to the second main surface 222a of the antenna section 22a. It is preferable that the first through hole has a tapered portion 224a in which the hole becomes smaller from the second main surface 222a to the first main surface 221a, and the second through hole has a tapered portion 224a in which the hole becomes smaller from the first main surface 221a to the second main surface 222a.

[0096] This makes it possible to prevent the screw 43, which is the mounting fixture, from protruding from the main surface of the antenna part 22a opposite the target object, regardless of whether the antenna part 22a is attached to the target object with the first main surface 221a or the second main surface 222a facing the target object.

[0097] As described above, it is preferable that the entire actuator 3 is disposed inside the object to which the actuator 3 is attached (in the above example, the frame 9b). This makes it possible to reduce the space between the object to which the actuator 3 is attached and the object to which the sensor head 2a is attached. In addition, it is possible to prevent the actuator 3 from colliding with other structures when the object to which the actuator 3 is attached moves (for example, when a door is opened or closed).

[0098] In the frame 9a, which is an object to which the sensor head 2 is attached, the outer surface 91 on the (-Y) side, the outer surface 92 on the (+X) side, and the outer surface 93 on the (-X) side are called the "first surface," the "second surface," and the "third surface," respectively. The second surface extends laterally from the first surface while inclining at an inclination angle of 90° in a plan view with respect to the first surface. The third surface extends laterally from the first surface at a position different from the second surface while inclining at an inclination angle of 90° in a plan view with respect to the first surface. In the state shown in FIG. 6 and FIG. 7, the head main body 21a is attached to the first surface of the object, and the antenna unit 22a is attached to the second surface of the object. In the state shown in FIG. 8 and FIG. 9, the head main body 21a is attached to the first surface of the object, and the antenna unit 22a is attached to the third surface of the object.

[0099] In this manner, in the safety switch 1a, the head body 21a is attached to a first surface of the object, and the antenna portion 22a is rotatable between a second position where it is attached to a second surface that extends while being inclined relative to the first surface of the object, and a third position where it is attached to a third surface that extends at a position different from the second surface while being inclined relative to the first surface of the object. This makes it possible to improve the degree of freedom in the arrangement of the antenna portion 22a and the head body 21a (i.e., the degree of freedom in the arrangement of the sensor head 2a) when attaching the sensor head 2a to the object, as described above.

[0100] 6 and 7, as described above, the head body 21a of the sensor head 2a with a rotation angle θ of 90° is attached to the outer surface 91 of the frame 9a, the antenna unit 22a is attached to the outer surface 92 of the frame 9a, and the cable 24a extends downward from the lower end of the head body 21a. In this case, the second main surface 212a of the head body 21a faces the outer surface 91 of the frame 9a, and the first main surface 221a of the antenna unit 22a faces the outer surface 92 of the frame 9a.

[0101] In the safety switch 1a, the head body 21a and the antenna part 22a of the sensor head 2a can be arranged so that the cable 24a extends upward from the upper end of the head body 21a as shown in FIG. 10 while maintaining the state in which the head body 21a and the antenna part 22a are attached to the outer surface 91 and the outer surface 92 of the frame 9a, respectively. In this case, the rotation angle θ of the sensor head 2a is set to 270°, the first main surface 211a of the head body 21a faces the outer surface 91 of the frame 9a, and the second main surface 222a of the antenna part 22a faces the outer surface 92 of the frame 9a. In this way, in the safety switch 1a, the position and the extending direction of the cable 24a can be changed significantly without changing the attachment positions of the head body 21a and the antenna part 22a on the object. Therefore, the degree of freedom in the arrangement of the sensor head 2a can be further improved.

[0102] Various modifications are possible to the above-described safety switches 1, 1a.

[0103] For example, the actuator 3 does not necessarily have to be entirely disposed inside the frame 9b, and only a part of the actuator 3 may be disposed inside the frame 9b, with the other part protruding outward from the outer surface of the frame 9b. Alternatively, the actuator 3 may be entirely disposed outside the frame 9b.

[0104] The shapes, arrangements, operating frequencies, types, etc. of the RFID tag 32 and the RFID readers 205, 205a are not limited to the above examples and may be modified in various ways.

[0105] The shape, number and arrangement of the through holes 213 provided in the head body 21 are not limited to the above example and may be modified in various ways. The same applies to the through holes 213a in the head body 21a. In addition, the method of attaching the head bodies 21, 21a to the frame 9a is not limited to the above example using the screws 41 and may be modified in various ways.

[0106] The shape, number and arrangement of the through holes 223 provided in the antenna unit 22 are not limited to the above example and may be modified in various ways. The same applies to the through holes 223a of the antenna unit 22a, and for example, the tapered portion 224a may be omitted from each of the through holes 223a. In the antenna unit 22a, the method of attaching the antenna units 22, 22a to the frame 9a is not limited to the above example using the screws 43 and may be modified in various ways.

[0107] The changeable range of the rotation angle θ of the antenna portion 22 with respect to the head body 21 is not limited to the above example and may be changed in various ways. The same applies to the rotation angle θ of the antenna portion 22a with respect to the head body 21a.

[0108] The shape of the head bodies 21, 21a does not necessarily have to be flat, and may be modified in various ways.

[0109] The shapes of the frames 9a, 9b are not limited to the above examples and may be modified in various ways. For example, the outer shape of the frames 9a, 9b in a plan view may be a triangle, a polygon with pentagons or more, a circle, an ellipse, or an oblong. The frames 9a, 9b may be frames made of a material other than aluminum. The object to which the sensor heads 2, 2a and the actuator 3 are attached is not limited to a frame and may be modified in various ways.

[0110] The configurations in the above-described embodiment and each of the modified examples may be combined as appropriate as long as they are not mutually inconsistent. [Explanation of symbols]

[0111] 1,1a safety switch 2,2a Sensor head 3 Actuator 9a,9b Frame 21,21a Head body 22, 22a Antenna section 32 RFID tags 43 Screw 91~94 External surface 205,205a RFID reader 211, 211a (of head body) first main surface 212, 212a (of head body) second main surface 213, 213a (head body) through hole 215, 215a Control section 221, 221a (antenna portion) first main surface 222, 222a (antenna portion) second main surface 223,223a (Antenna part) through hole 224,224a Tapered section 225,225a Antenna J1 Rotational Axis θ Rotation angle

Claims

1. A non-contact safety switch, an actuator having an RFID tag; a sensor head having an RFID reader that reads the code information stored in the RFID tag when the actuator approaches the sensor head; Equipped with The sensor head includes: a head body having a control unit of the RFID reader; a flat antenna portion having an antenna of the RFID reader and displaceably connected to the head body; Equipped with The antenna portion is connected to the head body via a rotation axis that extends linearly along the edge of the antenna portion, and the non-contact safety switch is displaced relative to the head body by rotating around the rotation axis.

2. 2. A non-contact safety switch according to claim 1, The head body is also flat, The non-contact safety switch is arranged such that the rotation axis is also along the edge of the head body.

3. 3. A non-contact safety switch according to claim 2, The antenna portion is a non-contact safety switch that can be arranged on the head body in an overlapping state with main surfaces facing each other.

4. 4. A non-contact safety switch according to claim 3, A non-contact safety switch in which a through hole is provided passing through the antenna portion and the head body in the thickness direction, and the sensor head is attached to an object by a mounting fixture inserted into the through hole.

5. 4. A non-contact safety switch according to claim 3, A non-contact safety switch in which the rotation angle of the antenna unit relative to the head body around the rotation axis is defined as 0° when the antenna unit overlaps the head body, and the rotation angle increases as the antenna unit rotates around the rotation axis and moves away from the head body, and the rotation angle can be changed within a range of 0° or more and 90° or less.

6. 2. A non-contact safety switch according to claim 1, A non-contact safety switch in which the rotation angle of the antenna unit relative to the head body around the rotation axis is defined as 0° when the antenna unit overlaps the head body, and the rotation angle increases as the antenna unit rotates around the rotation axis and moves away from the head body, and the rotation angle can be changed within a range of 90° or more and 270° or less.

7. 7. A non-contact safety switch according to claim 6, a first through hole and a second through hole respectively penetrating from a first main surface to a second main surface of the antenna portion are provided in the antenna portion; the first through hole includes a tapered portion in which the hole becomes smaller from the second main surface toward the first main surface, The second through hole has a tapered portion that becomes smaller from the first main surface toward the second main surface.

8. A non-contact safety switch, an actuator having an RFID tag; a sensor head having an RFID reader that reads the code information stored in the RFID tag when the actuator approaches the sensor head; Equipped with The sensor head includes: a head body having a control unit of the RFID reader; a flat antenna portion having an antenna of the RFID reader and rotatably connected to the head body; Equipped with The head body is attached to a first surface of an object, The antenna unit is a non-contact safety switch that is rotatable between a second position where it is attached to a second surface that extends while being inclined relative to the first surface of the object, a first position where it is attached to the first surface of the object via the head body, or a third position where it is attached to a third surface that extends while being inclined relative to the first surface of the object at a position different from the second surface.

9. A non-contact safety switch according to any one of claims 1 to 8, A non-contact safety switch in which the entire actuator is located inside the object to which the actuator is attached.

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