Mounting fixtures, mounting methods, multi-axis photoelectric sensors

Abstract

This improves the ease of adjusting the optical axis when fixing the light curtain to the mounting bracket. [Solution] The mounting fixture 2A is a component for attaching the housing 110 of the light curtain 1, which forms multiple optical axes Oax along the longitudinal direction x, to a base. The housing 110 has side wall portions Pa and Pb that are substantially parallel to the optical axis Oax in a cross-sectional view of zy perpendicular to the longitudinal direction x. The mounting fixture 2A includes a base portion 310 that is attached to the base and receives the housing 110 from the front, a temporary fixing portion 320 that temporarily fixes the housing 110 to the base portion 310 by elastic support, and a permanent fixing portion 330 that presses the housing 110 to permanently fix the rotational position of the housing 110 around its axis and the vertical position in the longitudinal direction x while the housing 110 is temporarily fixed to the base portion 310. The base portion 310 has rotation restricting portions P4 and P5 that contact the side wall portions Pa or Pb of the housing 110 while the housing 110 is temporarily fixed to the base portion 310, restricting the rotation of the housing 110 around its axis to a restricted range.

Description

Technical Field

[0001] The present invention relates to a fixture, a mounting method, and a multi-axis photoelectric sensor.

Background Art

[0002] A light curtain is one aspect of a multi-axis photoelectric sensor. The light curtain detects a person or an object according to whether a plurality of optical axes formed between a projector and a light receiver are blocked.

[0003] The light curtain is fixed to a base (base column) by a fixture. The main functions of the fixture include a function of adjusting the optical axis between the projector and the light receiver so that a desired light amount can be obtained for all optical axes, and a function of fixing the light curtain so that it does not shift against an impact or the like.

[0004] In the above optical axis adjustment, the vertical movement along the longitudinal direction (axial direction) of the light curtain and the rotational movement around the axis of the light curtain are performed individually. As a general work procedure, first, the vertical position of the light curtain with respect to the fixture is adjusted, and then the light curtain is temporarily fixed to the fixture at the adjusted vertical position. Next, after the rotational position around the axis of the light curtain is adjusted, the light curtain is fixedly attached to the fixture at the adjusted rotational position.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, some conventional fixtures fix the housing of the light curtain to the fixture by a screwing operation.

[0007] For example, in the multi-axis photoelectric sensor described in Patent Document 1, loosening the first bolt allows the vertical position of the light curtain to be adjusted, and tightening the first bolt fixes the vertical position of the light curtain. Furthermore, tightening the second bolt allows the rotational position of the light curtain around its axis to be adjusted, and loosening the second bolt fixes the rotational position of the light curtain around its axis.

[0008] The conventional mounting fixtures described above make it easy to use metal components, thus ensuring sufficient fixing force. However, they require multiple screw tightening operations, making them less efficient to use. For example, adjusting the optical axis of a light curtain while simultaneously adjusting the vertical position and rotational position using the conventional mounting fixtures described above is by no means an easy task.

[0009] In particular, with the conventional mounting device described above, loosening the second bolt allows the light curtain housing to rotate freely around its axis. Therefore, adjusting the optical axis can be extremely difficult for inexperienced operators.

[0010] Some conventional mounting fixtures have a cylindrical surface slightly smaller in diameter than the cylindrical light curtain, and the light curtain, which is fitted (inserted) into this cylindrical surface, is temporarily fixed by elastic support. With this configuration, it is easy to temporarily fix the light curtain, and it is easy to adjust the vertical position and the rotational position. However, it is difficult to use metal components, making it difficult to ensure sufficient fixing force. Also, since there is no restriction on rotational movement around the axis, it is not easy to adjust the rotational position.

[0011] In view of the above problems, the present invention aims to improve the ease of adjusting the optical axis when fixing a light curtain to a mounting fixture. [Means for solving the problem]

[0012] The mounting device according to the present invention is, for example, a mounting device for attaching a housing of a light curtain that forms a plurality of optical axes along its longitudinal direction to a base, wherein the housing has side walls that are substantially parallel to the optical axes in a cross-sectional view perpendicular to the longitudinal direction, and the mounting device comprises a base portion whose rear or side surface is attached to the base and which receives the housing from the front, a temporary fixing portion that temporarily fixes the housing to the base portion by elastic support, and a permanent fixing portion that permanently fixes the rotational position of the housing around its axis and the vertical position in the longitudinal direction by pressing the housing while the housing is temporarily fixed to the base portion, wherein the base portion has a rotation restricting portion that, while the housing is temporarily fixed to the base portion, contacts the side walls of the housing to restrict the rotation of the housing around its axis to a predetermined restricting range.

[0013] Further details regarding other features, elements, steps, advantages, and characteristics will become clearer from the embodiments for carrying out the invention and the accompanying drawings. [Effects of the Invention]

[0014] According to the present invention, with the light curtain housing temporarily fixed to the mounting fixture, the rotation angle around the housing's axis is restricted to a predetermined restricted range by the rotation restricting unit. Therefore, the user only needs to adjust the optical axis within the restricted range around the light curtain's axis, making optical axis adjustment easier. [Brief explanation of the drawing]

[0015] [Figure 1] This diagram shows the schematic configuration of a light curtain. [Figure 2] This is a perspective view showing the overall configuration of the floodlight. [Figure 3] This is a front view showing the overall configuration of the floodlight. [Figure 4] This is a perspective view showing one end of a floodlight. [Figure 5] This is a functional block diagram of the light curtain. [Figure 6] This is a diagram showing a first embodiment of a floodlight. [Figure 7]It is a diagram showing an example of the arrangement of light sources for indicator lights in the first embodiment. [Figure 8] It is a diagram showing the relationship between the emission color and the operation mode. [Figure 9] It is a diagram showing an example of the arrangement of light sources for indicator lights in the second embodiment. [Figure 10] It is a diagram showing an example of a display pattern in the second embodiment. [Figure 11] It is a diagram showing an example of the arrangement of light sources for indicator lights and an example of a display pattern in the third embodiment. [Figure 12] It is a diagram showing an example of the arrangement of light sources for indicator lights and an example of a display pattern in the fourth embodiment. [Figure 13] It is a diagram showing the relationship between the average light reception amount and the display pattern. [Figure 14] It is a diagram showing the relationship between the minimum light reception amount and the display pattern. [Figure 15] It is a diagram showing the lighting image (first example) of the light curtain. [Figure 16] It is a diagram showing the lighting image (second example) of the light curtain. [Figure 17] It is a functional block diagram of a light curtain equipped with a display pattern control function. [Figure 18] It is a diagram showing the processing flow of display pattern control. [Figure 19] It is a perspective view showing a resin type fixture. [Figure 20] It is a four-sided view showing a resin type fixture. [Figure 21] It is a diagram showing the state where the resin type fixture is attached to the base. [Figure 22] It is a diagram showing the state where the housing is attached to the resin type fixture. [Figure 23] It is a cross-sectional view showing the outer shape of the housing. [Figure 24] It is a cross-sectional view showing the state where the housing is attached facing the front. [Figure 25] It is a cross-sectional view showing the state where the rotation of the housing is restricted. [Figure 26]This is a perspective view showing a metal type mounting bracket. [Figure 27] This is a four-view drawing showing a metal type mounting bracket. [Figure 28] This diagram shows a metal mounting bracket attached to the base. [Figure 29] This diagram shows the housing attached to a metal mounting bracket. [Modes for carrying out the invention]

[0016] <Light Curtain> Figure 1 shows a schematic configuration of a light curtain. The light curtain 1 in this example configuration is one form of a multi-optical axis photoelectric sensor and generally comprises a pair of light emitters 100 and light receivers 200.

[0017] The light curtain 1 detects a person or object depending on whether at least one of the multiple optical axes (six optical axes Oax1 to Oax6 in this figure) that are spaced apart between the parallel-arranged light emitters 100 and light receivers 200 is blocked from light. For example, the light curtain 1 can be installed at the entrance or exit of a hazardous area where hazardous sources such as press equipment are placed, and used as a safety device to detect the intrusion or presence of workers.

[0018] The light emitter 100 and the light receiver 200 each comprise a long (maximum of 2m or more) housing 110 and 210, and cables 120 and 220 connected thereto.

[0019] The housing 110 has a hollow metal case 111 extending in the longitudinal direction, and hollow end caps 112 and 113 (corresponding to end members) connected to both ends of the metal case 111, respectively. Similarly, the housing 210 has a hollow metal case 211 extending in the longitudinal direction, and hollow end caps 212 and 213 (corresponding to end members) connected to both ends of the metal case 211, respectively. In this embodiment, the longitudinal direction is a direction substantially parallel to the direction in which the multiple optical axes formed between the light emitter 100 and the light receiver 200 are spaced apart from each other.

[0020] Thus, by using high-rigidity metal cases 111 and 211 as the cases for housings 110 and 210, the long housings 110 and 210 become less prone to deformation. Consequently, adjusting the placement of the light emitter 100 and light receiver 200 (for example, adjusting the angle to position them parallel) becomes relatively easy. Alternatively, inexpensive and lightweight extruded aluminum products may be used as the metal cases 111 and 211. In that case, the cross-section of the metal cases 111 and 211 will be the same shape regardless of where they are cut in the extrusion direction (=longitudinal direction).

[0021] The end caps 112, 113, 212, and 213 may each be formed by injection molding using a resin material, or by die casting using a metal material such as zinc. The lower end caps 113 and 213 in this figure may be fitted with interfaces for cables 120 and 220. Therefore, the end caps 113 and 213 may be larger than the upper end caps 112 and 212 in this figure.

[0022] <Floodlight> Figures 2 and 3 are perspective and front views, respectively, showing the overall configuration of the floodlight 100. Figure 4 is a perspective view showing one end of the floodlight 100.

[0023] As mentioned earlier, the floodlight 100 comprises a housing 110 and a cable 120. The housing 110 also includes a metal case 111 and end caps 112 and 113. Furthermore, the floodlight 100 includes a front cover 130, an indicator light 140, and a bumper section 150.

[0024] The front cover 130 is a long, translucent plate attached to cover the front opening (=detection window) of the housing 110. In the front opening of the housing 110, light-emitting elements 161 to 166, each for forming multiple optical axes Oax1 to Oax6, are arranged at equal intervals along the longitudinal direction. In other words, the front cover 130 is attached to the housing 110 so as to intersect with the multiple optical axes Oax1 to Oax6. The front cover 130 may be an extruded translucent resin plate (such as an acrylic plate) or a glass plate. In this embodiment, the translucency of the material used as the front cover 130 refers to a translucency such that the light from the light-emitting elements 161 to 166 forming the multiple optical axes Oax1 to Oax6 is not excessively diffused outside the optical axis, and is received by the light-receiving elements 261 to 266 (described later) with a certain amount of light or more. Since the front cover 130 is made of a light-transmitting material, the worker can see the light-emitting elements 161-166 through the front cover 130.

[0025] Furthermore, it is preferable that the end cap 113 has a light-emitting element (light-emitting element 166 in Figure 3) corresponding to at least one of the multiple optical axes Oax1 to Oax6. That is, it is preferable that the light-emitting elements 161 to 166 be arranged at equal intervals in the longitudinal direction over the entire length of the floodlight 100 from one end to the other. Also, it is preferable that the cable 120 extends from the back (or side) of the end cap 113 rather than from the bottom surface of the end cap 113. With this configuration, the floodlight 100 can be installed very close to the installation surface (floor, etc.). Therefore, dead space can be eliminated.

[0026] The indicator light 140 is controlled to flash on and off with a light color corresponding to, for example, the operating status of the light curtain 1 (such as the optical axis detection status and self-diagnosis results) or work instructions regarding the loading and unloading of objects. In other words, the indicator light 140 functions as an operation indicator light or a work instruction light. Therefore, by looking at the indicator light 140 of the light curtain 1, the worker can visually recognize the operating status of the light curtain 1 or work instructions.

[0027] In particular, the indicator light 140 is positioned longitudinally outward from at least one of the outer surfaces of the front cover 130 and the housing 110, or is formed in series with the front cover 130 (details of the structure will be described later). Referring to this figure, the indicator light 140 is provided on both sides of the front cover 130. With the indicator light 140 positioned or formed in this manner, a highly visible display can be provided without impairing the rigidity of the housing 110. More specifically, the indicator light 140 is a long extruded product, and is positioned so that the longitudinal direction of the indicator light 140 is aligned with the longitudinal direction of the housing 110. Note that the indicator light 140 only needs to be positioned along the longitudinal direction of the housing 110, and its manufacturing method is not limited to extrusion molding, and the shape of the indicator light 140 does not have to be long. For example, it may be a configuration in which multiple members that function as indicator lights 140 are positioned along the longitudinal direction of the housing 110.

[0028] Furthermore, the indicator light 140 is a light-diffusing member that diffuses light incident from an indicator light source 170 (not shown) housed inside the housing 110 in various directions. More specifically, the indicator light 140 contains a light diffuser that diffuses light in various directions. In a configuration where the light-diffusing member of the indicator light 140 contains a light diffuser, the indicator light 140 can be illuminated relatively uniformly even if the indicator light source 170 is small relative to the surface size of the indicator light 140, thus enabling a highly visible display. In this embodiment, the indicator light 140 is made of a transparent resin to which fine particles have been added, and is therefore milky white. If the base resin is not transparent but a specific color, the color will be a mixture of that specific color and milky white. In addition to the configuration containing a light diffuser, the indicator light 140 can also be made of a milky white resin (such as silicone) to achieve relatively uniform illumination. The light-diffusing member for the indicator light 140 can be any member that diffuses the light from the indicator light source 170 so that it can be seen from more directions, or any member that diffuses the light from the indicator light source 170 to such an extent that the outline of the indicator light source 170 is difficult to see from outside the indicator light 140. For example, a light-diffusing member whose surface is processed to diffuse the light from the indicator light source 170 may be arranged as the indicator light 140. As a surface processing that diffuses light, for example, texturing is known. With a configuration in which a light-diffusing member with a processed surface is arranged as the indicator light 140, it becomes easier to manufacture a member that has a region that diffuses light relatively easily and a region that does not diffuse light relatively easily.

[0029] The bumper section 150 protrudes outward from the region of the front cover 130's outer surface that intersects with multiple optical axes Oax1 to Oax6, and is positioned along the longitudinal direction of the housing 110 (details of the structure will be described later).

[0030] As shown in the figure, the bumper sections 150 are formed in pairs, protruding from both sides of the front cover 130. In other words, the front cover 130 is positioned in a narrow valley between the pair of bumper sections 150 (the twin bumpers proposed by the applicant) located on both sides and rising forward. Therefore, even if an object collides with the front of the floodlight 100, the impact is absorbed by the bumper sections 150. Consequently, the front cover 130 is less likely to be damaged. The bumper sections 150 may be made of a hard material such as metal.

[0031] Furthermore, the configuration of the light receiver 200 is basically the same as that of the light emitter 100. Therefore, in the explanatory text for Figures 2 to 4, the configuration of the light receiver 200 can be understood by appropriately substituting light emitter 100 and light-emitting elements 161 to 166 with light receiver 200 and light-receiving elements 261 to 266, respectively, and appropriately substituting other 100-series codes with 200-series codes. The same applies to the explanations that follow.

[0032] <Function Block> Figure 5 is a functional block diagram of the light curtain 1. In the light curtain 1 of this configuration example, the floodlight 100 includes an indicator light 140, light-emitting elements 161 to 166, a light source 170 for the indicator light, a control circuit 181, and a communication circuit 182.

[0033] The light-emitting elements 161 to 166 are arranged at equal intervals along the longitudinal direction of the light emitter 100 at a predetermined pitch. Based on the light emission control signal input from the control circuit 181, the light-emitting elements 161 to 166 sequentially emit multiple light beams toward the light receiver 200 (particularly the light-receiving elements 261 to 266) in a time-division manner to form multiple optical axes Oax1 to Oax6, respectively. Note that the light-emitting elements 161 to 166 may be, for example, light-emitting diodes that emit infrared light.

[0034] The indicator light source 170 supplies light to the indicator light 140 for display purposes based on the display control signal input from the control circuit 181. The indicator light source 170 may be capable of switching between multiple light emission colors (e.g., red, green, and orange) depending on the operating state of the light curtain 1 or work instructions.

[0035] Furthermore, the indicator light source 170 is preferably pulsed on at a timing that is temporally offset from the light emission / reception timing of each of the multiple optical axes Oax1 to Oax6. With this type of on / off control, interference with optical axis detection by the indicator light source 170 can be suppressed.

[0036] The indicator light 140 diffuses the light incident from the indicator light source 170 in various directions. By looking at the indicator light 140, the worker can visually recognize the operating status of the light curtain 1 or work instructions.

[0037] The control circuit 181 receives instructions from the light receiver 200 and generates a light emission control signal to sequentially drive the light-emitting elements 161 to 166 in a time-division manner. The control circuit 181 also generates a display control signal to turn the indicator light source 170 on and off with an arbitrary emission color. Furthermore, the control circuit 181 exchanges various information with the communication circuit 182.

[0038] The communication circuit 182 communicates with the light receiver 200 (particularly the communication circuit 282) via wired or wireless means. For example, the communication circuit 182 receives input from the light receiver 200 regarding the operating status of the light curtain 1 (such as the optical axis detection status and self-diagnosis results) and transmits it to the control circuit 181.

[0039] On the other hand, the light receiver 200 includes an indicator light 240, light receiving elements 261 to 266, a light source 270 for the indicator light, a control circuit 281, a communication circuit 282, an output circuit 283, and an input circuit 284.

[0040] The light-receiving elements 261 to 266 are arranged at equal intervals along the longitudinal direction of the light receiver 200, with the same pitch as the light-emitting elements 161 to 166. Based on the light-receiving control signal input from the control circuit 281, the light-receiving elements 261 to 266 sequentially receive multiple light beams in a time-division manner to form multiple optical axes Oax1 to Oax6. The light-receiving elements 261 to 266 may also be, for example, photodiodes or phototransistors that output an electrical signal corresponding to the amount of infrared light received.

[0041] The indicator light source 270 supplies light to the indicator light 240 for display based on the display control signal input from the control circuit 281. Like the indicator light source 170, the indicator light source 270 may be able to switch between multiple light emission colors (e.g., red, green, and orange) depending on the operating status of the light curtain 1 or work instructions.

[0042] Furthermore, the indicator light source 270 is preferably pulsed on at a timing that is temporally offset from the light emission / reception timing of each of the multiple optical axes Oax1 to Oax6. With this type of on / off control, interference with optical axis detection by the indicator light source 270 can be suppressed.

[0043] Furthermore, consider the case where the indicator light source 270 is continuously lit. In this case, even if the DC light from the indicator light source 270 is received by the light receiving elements 261 to 266, it is desirable to provide a saturation prevention circuit (= DC component subtraction circuit) so that the electrical signals output from the light receiving elements 261 to 266 do not become saturated.

[0044] The indicator light 240 diffuses the light incident from the indicator light source 270 in various directions. By looking at the indicator light 240, the worker can visually recognize the operating status of the light curtain 1 or work instructions.

[0045] Furthermore, since indicator lights 140 and 240 are provided on both the light emitter 100 and the light receiver 200, a highly visible display can be achieved.

[0046] The control circuit 281 generates a light receiving control signal to sequentially activate the light receiving elements 261 to 266 in a time-division manner, synchronized with the drive timing of each of the light-emitting elements 161 to 166. The control circuit 281 also generates a display control signal to turn the indicator light source 270 on and off with an arbitrary emission color. Furthermore, the control circuit 281 exchanges various information with the communication circuit 282, the output circuit 283, and the input circuit 284.

[0047] Furthermore, the control circuit 281 monitors the light-ingress / light-blocking state of each of the multiple optical axes Oax1 to Oax6. For example, the control circuit 281 may output an operation permission signal (ON signal) when all of the multiple optical axes Oax1 to Oax6 are in the light-ingress state. On the other hand, the control circuit 281 may output an operation disallowance signal (OFF signal) when at least one of the multiple optical axes Oax1 to Oax6 is in the light-blocking state.

[0048] Furthermore, the control circuit 281 may be equipped with a self-diagnosis function to determine whether it is in a state where it can correctly monitor the light-ingress / light-blocking state of each of the multiple optical axes Oax1 to Oax6. As a self-diagnosis method, for example, the control circuit 281 and the output circuit 283 (e.g., OSSD [Output Signal Switching Device] output) may be multiplexed, and the match / mismatch of the multiplexed signals may be determined.

[0049] For example, if the multiplexed signals match, an OK diagnosis (a diagnosis result indicating that the system is in a state where it can be properly monitored) is issued. On the other hand, if the multiplexed signals do not match, an NG diagnosis (a diagnosis result indicating that the system is not in a state where it can be properly monitored) is issued. In the event of an NG diagnosis, an operation prohibition signal (OFF signal) may be output regardless of the light input status of each of the multiple optical axes Oax1 to Oax6.

[0050] Information that can be used for safety control is designated as safety information, while general information that cannot be used for safety control is designated as non-safety information. For example, the OSSD output is a type of safety information. The signals used to control the on / off state of the indicator light sources 170 and 270 may be signals indicating safety information or signals indicating non-safety information.

[0051] The communication circuit 282 communicates with the floodlight 100 (particularly the communication circuit 182) by wire or wireless means. The communication circuit 282 receives information from the control circuit 281 regarding the operating status of the light curtain 1 (such as the optical axis detection status and self-diagnosis results) and transmits it to the floodlight 100.

[0052] The output circuit 283 communicates with external devices (e.g., safety controllers) via wired or wireless means. For example, the output circuit 283 receives input from the control circuit 281 regarding the operating status of the light curtain 1 (such as the optical axis detection status and self-diagnosis results) and transmits it to the external devices.

[0053] The input circuit 284 communicates with external devices (e.g., safety controllers) via wired or wireless means. For example, the input circuit 284 receives input from external devices regarding work instructions for loading and unloading objects and transmits them to the control circuit 281.

[0054] <First Embodiment> Figure 6 is a diagram showing a first embodiment of the floodlight 100 (a schematic cross-sectional view when the metal case 111 of the floodlight 100 is cut at an arbitrary position in the longitudinal direction). The floodlight 100 of this embodiment comprises a housing 110 (only the metal case 111 is depicted in this figure), a front cover 130, an indicator light 140, a bumper portion 150, a light source for the indicator light 170, a circuit board 190, and a light shielding plate 191.

[0055] The metal case 111 is an extruded product that extends in the longitudinal direction of the floodlight 100. As shown in the figure, the metal case 111 consists of a main body 111a, a pair of first protrusions 111b, and a pair of second protrusions 111c.

[0056] The main body 111a is a hollow member with a U-shaped cross-section and an opening on the upper side of the paper (= the front side of the floodlight 100). The internal space of the main body 111a houses the indicator light source 170, the substrate 190, and the light shielding plate 191.

[0057] A pair of first protruding strips 111b project inward from the inner surfaces of the left and right walls of the main body 111a toward the inside of the opening. That is, the pair of first protruding strips 111b are arranged facing each other at a predetermined distance, straddling the optical axis intersection region X (= the region where multiple optical axes Oax1 to Oax6 intersect). The pair of first protruding strips 111b also function as cover mounting parts for supporting the front cover 130. As described above, a translucent material is used for the front cover 130, but it is sufficient that at least the optical axis intersection region X is translucent and the optical axes Oax1 to Oax6 are not obstructed. For example, in this embodiment, the portion that contacts the pair of first protruding strips 111b does not necessarily have to be translucent.

[0058] A pair of second protrusions 111c extend further upward from the upper ends of the left and right walls of the main body 111a. Furthermore, the tips of each of the second protrusions 111c are bent inward towards the opening. The pair of second protrusions 111c function as a bumper portion 150 to protect the front cover 130. In this embodiment, the aforementioned bumper portion 150 is formed from the metal case 111. Therefore, the robustness of the floodlight 100 can be increased.

[0059] The front cover 130 is supported (suspended) at both ends, straddling a pair of first protruding strips 111b. The front cover 130 allows light to pass through that forms multiple optical axes Oax1 to Oax6 in the optical axis intersection region X. The area between the front cover 130 and the pair of first protruding strips 111b (see thick line α) is treated to improve liquid resistance. For example, a packing is placed, or it is bonded with a liquid-resistant adhesive. As will be described later, the indicator light 140 increases the adhesion between the front cover 130 and the first protruding strips 111b, further improving liquid resistance.

[0060] The indicator lights 140 are positioned on both sides of the front cover 130, adjacent to the bumper section 150. Referring to this figure, the indicator lights 140 are positioned along the longitudinal direction of the floodlight 100 in the area sandwiched between the tip (bent portion) of the first protruding strip 111b and the second protruding strip 111c, that is, in the area sandwiched between the bumper section 150 and the front cover 130.

[0061] The indicator light 140 diffuses the light incident from the indicator light source 170 through the front cover 130 in various directions. For example, the indicator light 140 may be provided with a taper to refract and diffuse the light incident from the indicator light source 170 toward the inside of the opening.

[0062] With the indicator lights 140 arranged in this manner, they are easily visible even from the side of the floodlight 100. Therefore, in a small (slim-diameter) light curtain 1 using a metal case 111, highly visible displays can be provided without compromising the rigidity of the housing 110. In particular, when a pair of bumper sections 150 are provided protruding from both sides of the front cover 130, the improvement in visibility due to the above arrangement can become even more pronounced.

[0063] Furthermore, in the floodlight 100 of this embodiment, the indicator light 140 also functions as a pressing member for pressing and fixing the front cover 130 downward (towards the first protruding strip 111b). Therefore, the airtightness between the front cover 130 and the first protruding strip 111b is increased, which prevents liquid from entering the inside of the metal case 111 and improves liquid resistance. In order for the indicator light 140 to function as a pressing member, it is desirable that the indicator light 140 has appropriate elasticity.

[0064] The indicator light source 170 is mounted on the main surface of the substrate 190 (= the surface facing the front cover 130). The indicator light source 170 supplies light for display to the indicator light 140 via the front cover 130. As shown in this figure, the light emitted from the indicator light source 170 passes between the pair of first protruding strips 111b without being obstructed by the pair of first protruding strips 111b and is supplied to the indicator light 140 via the front cover 130.

[0065] The number of indicator light sources 170 is not limited. For example, the indicator light sources 170 may be arranged intermittently in multiple locations along the longitudinal direction of the floodlight 100, or they may be formed in a continuous series.

[0066] Furthermore, the indicator light source 170 may be equipped with a lens for controlling the direction of the emitted light. For example, a lens may be provided that is optically designed to reduce the angle of light spread in the left-right direction of the figure and increase the angle of light spread in the depth direction of the figure. Such a lens makes it possible to reduce the number of indicator light sources 170 while suppressing interference with multiple optical axes Oax1 to Oax6.

[0067] The type of lens may be a point-symmetric lens (single arrangement) or a cylindrical lens (series arrangement of extruded products).

[0068] The light-shielding plate 191 is provided between the indicator light source 170 and the optical axis intersection region X. Therefore, since the light from the indicator light source 170 toward the optical axis intersection region X is blocked, the light emitted from the indicator light source 170 is less likely to interfere with the multiple optical axes Oax1 to Oax6.

[0069] Furthermore, consider the case where the optical axis Oax1 to Oax6 is formed by infrared light, and visible light (red light, green light, or orange light, etc.) is emitted from the indicator light source 170. In this case, a filter that transmits infrared light and blocks visible light may be provided in the light receiver 200. In particular, when an indicator light 240 is provided in the light receiver 200, it is sufficient to have a configuration in which a filter that transmits infrared light and blocks visible light is arranged so as not to obstruct the display of the indicator light 240. The filter may be provided in the light receiving elements 261 to 266, or it may be provided in the lens that guides light to the light receiving elements 261 to 266.

[0070] Figure 7 shows an example of the arrangement of the indicator light source 170 in the first embodiment. As shown in this figure, the light-emitting elements 161 to 166 may be arranged at equal intervals along the longitudinal direction of the substrate 190 in the central region 190a of the substrate 190. On the other hand, the indicator light source 170 may be arranged at equal intervals along the longitudinal direction of the substrate 190 in the end region 190b of the substrate 190.

[0071] In particular, the light-emitting elements 161-166 and the indicator light source 170 may be arranged so that their positions in the longitudinal direction of the substrate 190 are offset from each other (staggered). With such an arrangement, mutual interference between the light-emitting elements 161-166 and the indicator light source 170 is suppressed.

[0072] The number and arrangement of the indicator light sources 170 are not limited to the arrangement example shown in this figure. For example, the number of indicator light sources 170 may be reduced so that there is some unevenness in the light supplied to the indicator lights 140.

[0073] <Display contents> Figure 8 shows the relationship between the light emission color of the indicator light 140 and its operating mode. As shown in this figure, the indicator light 140 can be switched between operation indicator light mode and work indicator light mode. For example, the control signal for switching the operating mode of the indicator light 140 may be a 2-bit (4-value) digital signal input to the input circuit 284.

[0074] First, let's explain the case where the indicator light 140 is set to operation indicator light mode. When the indicator light 140 is set to operation indicator light mode, it is controlled to turn on and off with a light color corresponding to the operating status of the light curtain 1.

[0075] Referring to this diagram, for example, when the light curtain 1 is in a normal state (for example, when none of the multiple optical axes Oax1 to Oax6 are blocked), the indicator light 140 lights up green. On the other hand, when the light curtain 1 is in an abnormal state (for example, an emergency stop state where at least one of the multiple optical axes Oax1 to Oax6 is blocked), the indicator light 140 lights up red. Also, when the light curtain 1 is in an alarm notification state (for example, an NG diagnosis state by the self-diagnosis function), the indicator light 140 flashes red.

[0076] Next, we will describe the case when the indicator light 140 is set to work instruction light mode. When the indicator light 140 is set to work instruction light mode, it is controlled to turn on and off with a light color corresponding to the work instruction signal received by the input circuit 284.

[0077] Referring to this diagram, for example, when the work instruction signal indicates "work permitted," the indicator light 140 lights up green. On the other hand, when the work instruction signal indicates "work prohibited," the indicator light 140 lights up red. Also, when the work instruction signal indicates "self-diagnosis," the indicator light 140 blinks red. In addition, in work instruction light mode, the indicator light 140 may light up orange. The way in which these lighting states are used may vary depending on the user.

[0078] Furthermore, if the light curtain 1 is used in an environment where the illumination of the indicator light 140 is undesirable, it is possible to keep the indicator light 140 constantly off.

[0079] <Considerations regarding the decrease in light intensity of optical bearings> As explained earlier, a light curtain consists of two components: a light emitter and a light receiver, with multiple light-emitting and light-receiving elements arranged axially. When using a light curtain, the light emitter and light receiver should be positioned parallel to each other, and their angles adjusted so that light is received by all elements. The greater the distance between the light emitter and light receiver, the more difficult it becomes to determine if the orientation is correct, and the harder it is to see the display. Therefore, adjusting the angles becomes more difficult.

[0080] Light curtains are sometimes used in harsh environments where they may be exposed to dirt or impacts. Therefore, some products feature a bumper-shaped protrusion extending beyond the front cover to protect the detection unit's front cover. However, preventing dirt from accumulating on the front cover is difficult. If dirt builds up and the light-receiving element can no longer receive sufficient light, the optical axis may become obscured, potentially causing the device to shut down due to a safety output from the light curtain. Therefore, maintenance cleaning of the front cover's glass surface is necessary before it affects the optical axis detection results.

[0081] In environments where dirt accumulates, it is necessary to install light curtains to ensure sufficient optical bearing light intensity to compensate for the decrease in optical bearing light intensity (= the amount of light received by each optical axis, which is the criterion for determining whether or not the optical axis is in a state of light blocking) due to dirt. Furthermore, it is necessary to monitor the decrease in optical bearing light intensity over time and perform maintenance before the optical axis becomes completely blocked.

[0082] In response to the above requirements, there are models of light curtains that allow you to check the light bearing intensity on the unit itself. For example, some existing models express the light bearing intensity by the number of lit LEDs (light-emitting diodes) or by a 7-segment digital display. However, these displays are small and difficult to see from a distance. Therefore, it can be difficult to check the display when installing and adjusting the light curtain. Also, even during operation of the light curtain, it is difficult to notice a decrease in the light bearing intensity unless you consciously check the small display mentioned above.

[0083] On the other hand, the light curtain 1 described herein is equipped with large indicator lights 140 and 240 so that the operating status of the light curtain 1 can be easily seen, while maintaining both miniaturization and high visibility.

[0084] In light of the above considerations, we propose a novel embodiment below in which the highly visible indicator lights 140 and 240 described above can display information linked to the light intensity of the optical bearing.

[0085] <Second Embodiment> Figure 9 shows an example of the arrangement of light sources for indicator lights in the second embodiment. In this embodiment, multiple (two in this figure) substrates 190 having the same structure are cascaded along the longitudinal direction. With such a configuration, the length of the light curtain 1 can be easily increased simply by increasing the number of cascaded substrates 190.

[0086] In this figure illustrating the light emitter 100, the light-emitting elements 161 to 166 may be arranged at equal intervals along the longitudinal direction of the substrate 190 in the central region 190a of the substrate 190, as in Figure 7 above. Referring to this figure, on the substrate 190 on the right side of the page, the light-emitting elements 161 to 163 are arranged from right to left in the order shown in the figure. On the other hand, on the substrate 190 on the left side of the page, the light-emitting elements 164 to 166 are arranged from right to left in the order shown in the figure. When understanding the configuration of the light receiver 200, the light-emitting elements 161 to 166 can be replaced with light-receiving elements 261 to 266, respectively.

[0087] On the other hand, the indicator light sources 170 may be arranged at equal intervals along the longitudinal direction of the substrate 190 in the edge region 190b of the substrate 190. In particular, the indicator light sources 170 can be distinguished as indicator light sources 170a, 170b, and 170c depending on the differences in their respective control systems. Referring to this figure, the indicator light sources 170a, 170b, and 170c are arranged on the two substrates 190 in the order shown, from left to right on the page. Although not shown in this figure, the light curtain 1 is equipped with an OSSD indicator light whose display mode changes according to the OSSD output, separate from the indicator light sources 170. Therefore, the display mode of the indicator light sources 170 changes to indicate the light receiving state of the light receiving elements 261 to 266.

[0088] As described above, the light-emitting elements 161-163 (or 164-166) and the indicator light sources 170a, 170b, and 170c are arranged as a single unit on a common substrate 190. In particular, the indicator light sources 170a, 170b, and 170c are unitized as a set of three.

[0089] As a variation, the light-emitting elements 161-163 (or 164-166) and the indicator light sources 170a, 170b, and 170c may each be separate units. That is, the unit in which the light-emitting elements 161-163 (or 164-166) are arranged and the unit in which the indicator light sources 170a, 170b, and 170c are arranged may be independent.

[0090] Figure 10 shows an example of a display pattern in the second embodiment. The upper part of this figure depicts the "a-lighted state". In this "a-lighted state", the indicator light source 170a is lit, while both indicator light sources 170b and 170c are off. Therefore, the display pattern is one light on, two lights off, repeated from left to right on the page.

[0091] The middle section of this diagram depicts the "ab-lighted state." In this "ab-lighted state," both indicator light sources 170a and 170b are lit, while indicator light source 170c is off. Therefore, the display pattern repeats from left to right on the page, with "two lights on, one off."

[0092] The lower part of this diagram depicts the "abc lit state." In this "abc lit state," the indicator light sources 170a, 170b, and 170c are all lit.

[0093] Thus, in the example display pattern of this embodiment, the indicator light sources 170a, 170b, and 170c are illuminated at appropriate intervals. Therefore, by switching the display pattern to one of the three above according to the optical bearing light intensity, the optical bearing light intensity can be determined simply by looking at the large indicator lights 140 and 240. As a result, a light curtain 1 is provided that is easy to adjust during initial setup and has high maintainability.

[0094] <Third Embodiment> Figure 11 shows an example of the arrangement of indicator light sources and an example of a display pattern in the third embodiment. In this embodiment, two each of the indicator light sources 170a, 170b, and 170c are arranged on a common substrate 190 as a single unit. That is, the indicator light sources 170a, 170b, and 170c are unitized in sets of six.

[0095] Referring to this figure, the circuit board 190 has two indicator light sources 170a, 170b, and 170c arranged in the order shown, from left to right on the page.

[0096] The upper part of this diagram depicts the "a-lighting state." In this "a-lighting state," indicator light source 170a is lit, while indicator light sources 170b and 170c are both off. Therefore, the display pattern repeats from left to right on the page, with "two lights on, four lights off."

[0097] The middle section of this diagram depicts the "ab-lighted state." In this "ab-lighted state," both indicator light sources 170a and 170b are lit, while indicator light source 170c is off. Therefore, the display pattern repeats from left to right on the page, with "four lights on, two off."

[0098] The lower part of this diagram depicts the "abc lit state." In this "abc lit state," the indicator light sources 170a, 170b, and 170c are all lit.

[0099] In the second embodiment described above (Figure 10), the number of indicator light sources 170a, 170b, and 170c, which are in a non-lit state (off state), is increased or decreased by one for each display pattern, such as 2, 1, and 0.

[0100] On the other hand, in the example arrangement of indicator light sources and display patterns of this embodiment, the number of indicator light sources 170a, 170b, and 170c that are not lit increases or decreases by two for each display pattern, to 4, 2, and 0, respectively. Therefore, compared to the second embodiment described above (Figure 10), the difference in distance between the light sources that are partially lit becomes larger. As a result, it becomes easier to recognize the switching of the display pattern (and consequently the change in the amount of light in the optical bearing) even when passing through the light diffuser.

[0101] <Fourth Embodiment> Figure 12 shows an example of the arrangement of indicator light sources and an example of the display pattern in the fourth embodiment. In this embodiment, as in the second embodiment (Figure 10) described above, the indicator light sources 170a, 170b, and 170c are unitized as a set of three. However, the arrangement order of the indicator light sources 170a, 170b, and 170c differs for each substrate 190.

[0102] Referring to this figure, on the circuit board 190 on the left side of the figure, indicator light sources 170a, 170b, and 170c are arranged in the order shown, from left to right on the page. On the other hand, on the circuit board 190 on the right side of the figure, indicator light sources 170a, 170b, and 170c are arranged in the order shown, from right to left on the page.

[0103] The upper part of this diagram depicts the "a-lighting state." In this "a-lighting state," indicator light source 170a is lit, while indicator light sources 170b and 170c are both off. Therefore, the display pattern repeats from left to right on the page: "one lit, four off, one lit."

[0104] The middle section of this diagram depicts the "ab-lighted state." In this "ab-lighted state," both indicator light sources 170a and 170b are lit, while indicator light source 170c is off. Therefore, the display pattern repeats from left to right on the page: "one off, four on, one off."

[0105] Thus, with the example arrangement of indicator light sources and display patterns in this embodiment, while maintaining a set of three units, the number of indicator light sources 170a, 170b, and 170c that are kept in a non-illuminated state increases or decreases by two for each display pattern, such as 4, 2, and 0. Therefore, as with the third embodiment described above (Figure 11), it becomes easier to recognize the switching of the display pattern (and consequently the change in the light intensity of the optical bearing).

[0106] <Relationship between optical bearing light intensity and display pattern> Figure 13 shows the relationship between the optical bearing light intensity (average light received) and the display pattern. The optical bearing light intensity is converted by an A / D converter and compared with a threshold. The criterion for determining the display pattern may also be the average value of the light received at each optical axis (= average light received).

[0107] First, the ON state of the OSSD indicates that the condition "the amount of light received by all optical axes is above the first threshold" is met for the photodetectors 261 to 266, and the OSSD output is ON. In this embodiment, for convenience, the state in which the photodetectors 261 to 266 meet this condition and the OSSD output can be turned ON is defined as the ON state, and the ON state is the state in which "the amount of light received by all optical axes is above the first threshold." The first threshold mentioned above is the same as the threshold used to determine whether each individual optical axis is in a light-shielding state or not. Therefore, the average amount of light received in that state is relatively high and cannot be as low as a value considered to be "completely shielded." In other words, since the amount of light received by all optical axes is above the first threshold, it is impossible for the average amount of light received to fall below the first threshold.

[0108] Therefore, the "off" display when the average light reception amount falls below the first threshold can be understood as a display mode that exists only when the light-receiving elements 261-266 do not satisfy the condition that "the light reception amount for all optical axes is above the first threshold," i.e., when the judgment is OFF. In this figure, a horizontal axis is introduced to clarify this. The horizontal axis shows the result of the individual light reception amount judgment for each optical axis (= the number of optical axes judged to be in a shaded state by the individual optical axis judgment). Note that the OSSD OFF state indicates that the condition that "the light reception amount for all optical axes is above the first threshold" is not satisfied for the light-receiving elements 261-266, and the OSSD output is OFF. In this embodiment, for convenience, the judgment OFF state is defined as the state when the light-receiving elements 261-266 do not satisfy the condition that "the light reception amount for all optical axes is above the first threshold," i.e., when "the light reception amount for at least one optical axis is below the first threshold." In other words, in the judgment ON state, the number of shaded optical axes is 0. On the other hand, in the judgment OFF state, the number of shaded optical axes is 1 or more.

[0109] It should be noted that the individual light reception amount judgment for each optical axis is solely for switching between the judgment ON state (display color: green) and the judgment OFF state (display color: red). Therefore, the step for making this judgment in the flowchart shown later is the same step as the step for comparing the average light reception amount with the threshold.

[0110] Furthermore, the thresholds used to determine the number of illuminated indicator light sources 170a, 170b, and 170c are shifted between the ON and OFF states. First, let's explain the ON state. As mentioned earlier, the ON state is when the amount of light received by all optical axes is above the first threshold. Therefore, in the ON state, thresholds for switching the number of illuminated lights (the fourth and fifth thresholds in this diagram) are set in the region where the average amount of light received is relatively high.

[0111] As shown in this diagram, when the judgment is ON and the average light received is lower than the fourth threshold, one green light will illuminate (meaning only the indicator light source 170a will be illuminated green). When the average light received is higher than the fourth threshold but lower than the fifth threshold, two green lights will illuminate (meaning both indicator light sources 170a and 170b will be illuminated green). When the average light received is higher than the fifth threshold, three green lights will illuminate (meaning indicator light sources 170a, 170b, and 170c will be illuminated green). In other words, the number of illuminated green lights increases as the average light received increases.

[0112] Furthermore, the amount of light received by each optical axis decreases as the distance between the light emitter 100 and the light receiver 200 increases. It is conceivable that even if the light emitter 100 and the light receiver 200 are installed parallel to each other as specified, and are free of dirt and receiving light normally, the amount of light received may decrease solely due to an increase in the distance between the light emitter 100 and the light receiver 200.

[0113] In this situation, reducing the number of illuminated indicator light sources 170a, 170b, and 170c would prevent the correct transmission of information related to installation and maintenance. Therefore, it is desirable to set the threshold so that the range in which three indicator light sources 170a, 170b, and 170c are illuminated is wide. Referring to this figure, in the ON state of the judgment, the fifth threshold for switching between three illuminated indicator light sources 170a, 170b, and 170c and two illuminated is set relatively low.

[0114] Next, we will explain the OFF state. Switching the display pattern in the OFF state is useful when installing the light emitter 100 and light receiver 200. For example, consider the case where you start from an off state with 0 lights on and adjust the installation positions of the light emitters 100 and 200. In this case, it is desirable that the display pattern switches even if the average light received increases or decreases only slightly, in order to understand the direction of the adjustment (i.e., whether or not you are approaching the correct installation position).

[0115] Therefore, in the OFF state, thresholds for switching the number of lights on (first threshold, second threshold, and third threshold in this figure) are set in a region where the average light reception is relatively low. For example, the relationship between the thresholds may be first threshold < second threshold < third threshold < fourth threshold < fifth threshold, as shown in this figure. In the embodiment shown in this figure, the first threshold, second threshold, and third threshold do not affect the switching of the number of lights on in the ON state.

[0116] As shown in the diagram, when the judgment is OFF and the average light received is lower than the first threshold, the lights will be off as previously described (= the indicator light sources 170a, 170b, and 170c will be turned off). When the average light received is higher than the first threshold but lower than the second threshold, one red light will be on (= only indicator light source 170a will be lit red). When the average light received is higher than the second threshold but lower than the third threshold, two red lights will be on (= indicator light sources 170a and 170b will be lit red). When the average light received is higher than the third threshold, three red lights will be on (= indicator light sources 170a, 170b, and 170c will be lit red). In other words, the number of red lights increases as the average light received increases.

[0117] Thus, the purpose of switching the display pattern according to the light intensity of the optical bearing differs between the ON and OFF states. Specifically, the green light display pattern switch in the ON state is expected to be useful for identifying dirt accumulation (the need for maintenance) after the start of operation of Light Curtain 1. On the other hand, the red light display pattern switch in the OFF state is expected to be useful for adjusting the optical axis when installing Light Curtain 1. Therefore, in order to individually set the optimal threshold for the ON and OFF states, it is desirable to stagger the thresholds between the ON and OFF states.

[0118] However, conversely, there are also advantages to setting the thresholds to match the ON and OFF states. For example, in this diagram, looking only at the average light reception, the "one green light" in the ON state and the "three red lights (or two red lights)" in the OFF state are adjacent. Therefore, when the optical axis is blocked while maintaining the average light reception, and the system switches from the ON state to the OFF state, the display pattern switches from "one green light" to "three red lights (or two red lights)".

[0119] In other words, if we focus solely on the number of lights illuminated, there is a risk of an unnatural display pattern switching where the number of lights illuminated increases even though the optical axis is blocked. Therefore, if the priority is to clearly communicate the optical axis light intensity, it is desirable to keep the threshold the same for the ON and OFF states of the judgment to prevent the aforementioned reversal of the number of lights illuminated.

[0120] Figure 14 shows the relationship between the light intensity of the optical bearing (minimum light intensity) and the display pattern. As shown in this figure, the criterion for determining the display pattern may be the minimum value of the amount of light received at each optical axis (= minimum light intensity).

[0121] In this case, for example, a first threshold, a second threshold, and a third threshold may be set. The relationship between each threshold may be first threshold < second threshold < third threshold.

[0122] As shown in this diagram, when the minimum light intensity is lower than the first threshold, three red lights illuminate (= indicator light sources 170a, 170b, and 170c are illuminated in red). This state corresponds to the OFF state. Thus, in the OFF state, the number of illuminated red lights is fixed at three. When the minimum light intensity is higher than the first threshold but lower than the second threshold, one green light illuminates (= only indicator light source 170a is illuminated in green). When the minimum light intensity is higher than the second threshold but lower than the third threshold, two green lights illuminate (= indicator light sources 170a and 170b are illuminated in green). When the minimum light intensity is higher than the third threshold, three green lights illuminate (= indicator light sources 170a, 170b, and 170c are illuminated in green). In other words, the number of illuminated green lights increases as the minimum light intensity increases.

[0123] Thus, as a criterion for determining the display pattern, either the average value of the amount of light received in each optical axis (= average light received) or the minimum value (= minimum light received) may be used.

[0124] <Image of lights up> Figure 15 shows an image of the lighting of the light curtain 1 (first example). In this figure, the arrangement example of the indicator light sources 170a, 170b, and 170c and the display pattern are the same as those of the second embodiment described above (Figures 9 and 10). Furthermore, the relationship between the light intensity of the optical bearing and the display pattern is the same as the display pattern switching control described above in Figure 13.

[0125] First, let's explain the OFF state (the four states on the left side of this diagram). In the completely blackout state, light curtain 1 is turned off (= indicator light sources 170a, 170b, and 170c are turned off). At low light intensity, one red light is lit (= only indicator light source 170a is lit red). At medium light intensity, two red lights are lit (= indicator light sources 170a and 170b are lit red). At high light intensity, three red lights are lit (= indicator light sources 170a, 170b, and 170c are lit red).

[0126] Next, let's explain the ON state (the three states on the right in this diagram). At low light intensity, one green light is illuminated (= only indicator light source 170a is illuminated in green). At medium light intensity, two green lights are illuminated (= indicator light sources 170a and 170b are illuminated in green). At high light intensity, three green lights are illuminated (= indicator light sources 170a, 170b, and 170c are illuminated in green).

[0127] Furthermore, diffusers are placed above each of the indicator light sources 170a, 170b, and 170c. Therefore, it is desirable to appropriately set the arrangement and display patterns of the indicator light sources 170a, 170b, and 170c so that the change in the display pattern can be recognized even through the diffusers. This point has been mentioned earlier.

[0128] Figure 16 shows an image of the lighting of the light curtain 1 (second example). In this figure, the light curtain 1 displays a bar according to the light intensity of the optical bearing. Specifically, the three circuit boards 190x, 190y, and 190z (more precisely, a group of indicator light sources 170 incorporated into each) that are cascaded in the longitudinal direction of the light curtain 1 are each controlled to turn on and off as individual units.

[0129] First, let's explain the OFF state (the four states on the left side of this diagram). In the completely darkened state, light curtain 1 is turned off (= the circuit board 190x, 190y, and 190z are turned off). At low light intensity, 1 / 3 of light curtain 1 is illuminated in red (= only circuit board 190x is illuminated in red). At medium light intensity, 2 / 3 of light curtain 1 is illuminated in red (= circuit board 190x and 190y are illuminated in red). At high light intensity, the entire (3 / 3) of light curtain 1 is illuminated in red (= circuit board 190x, 190y, and 190z are illuminated in red).

[0130] Next, let's explain the ON state (the three states on the right in this diagram). With low light intensity, 1 / 3 of light curtain 1 will light up in green (= only circuit board 190x will light up in green). With medium light intensity, 2 / 3 of light curtain 1 will light up in green (= circuit boards 190x and 190y will light up in green). With high light intensity, the entire (3 / 3) of light curtain 1 will light up in green (= circuit boards 190x, 190y and 190z will light up in green).

[0131] Thus, with the lighting image of the second example (Figure 16), the switching of the display pattern according to the light intensity of the optical bearing is easier to understand compared to the first example (Figure 15). However, if the above lighting image is to be realized based on a configuration in which multiple circuit boards 190x, 190y, and 190z are cascaded, the design difficulty and cost may increase.

[0132] <Examples of display patterns according to the light intensity of the optical bearing> The above example illustrates a configuration in which the number of indicator light sources 170 illuminated (especially the decimation interval) is switched according to the light intensity of the optical bearing, but various other modifications are also possible.

[0133] For example, the indicator light 140 may be switched to change over time according to the amount of light from the optical bearing (for example, keeping the indicator light 140 constantly lit, flashing at 1-second intervals, or flashing at 2-second intervals). Alternatively, the amount of light emitted or the color of light emitted by the indicator light 140 may be switched according to the amount of light from the optical bearing. When these embodiments are adopted, it becomes unnecessary to individually control multiple indicator light sources 170 when switching display patterns. Therefore, it becomes possible to use, for example, an optical fiber as the indicator light 140.

[0134] <Functional block (with display pattern control function)> Figure 17 is a functional block diagram of the light curtain 1 equipped with a display pattern control function. Note that this figure is based on the previously mentioned Figure 5, but focuses on the control systems of the indicator light sources 170a, 170b, and 170c, and the indicator light sources 270a, 270b, and 270c, rather than the light emission / receiving systems of the optical axes Oax1 to Oax6.

[0135] Furthermore, in this figure, following the second embodiment described above (Figures 9 and 10), the indicator light sources 170a, 170b, and 170c, and the indicator light sources 270a, 270b, and 270c, are each arranged in sets of three in the order shown in the figure (a, b, c, a, b, c from the top of the page).

[0136] The control circuit 181 controls the two indicator light sources 170a with a common control signal. The same applies to the indicator light sources 170b and 170c. Similarly, the control circuit 281 controls the two indicator light sources 270a with a common control signal. The same applies to the indicator light sources 270b and 270c.

[0137] The amount of light received by each of the optical axes Oax1 to Oax6 is compared with a threshold value by the control circuit 281. In this case, the control circuit 281 may include an analog-to-digital conversion circuit that converts the analog signals output from each of the photodetectors 261 to 266 into digital signals. The control circuit 281 may also include a calculation circuit that calculates the average value (=average light received) or the minimum value (=minimum light received) from the light received by each of the optical axes Oax1 to Oax6.

[0138] The control circuit 281 controls the on / off states of the indicator light sources 270a, 270b, and 270c based on the comparison result between the average light received (or minimum light received) and a threshold. The control circuit 281 also transmits the above comparison result to the control circuit 181 via the communication circuits 282 and 182. The control circuit 181 controls the on / off states of the indicator light sources 170a, 170b, and 170c based on the above comparison result transmitted from the control circuit 281.

[0139] <Processing Flow> Figure 18 shows the processing flow for display pattern control based on the average light reception amount. When the processing flow shown in this figure starts, in step S1, the optical axis to be driven, Oax(i) (where i=1, 2, ... imax(6), and the initial setting value is i=1), is set.

[0140] In the following step S2, the light-emitting element 16i is turned on. Specifically, the light-emitting element 161, which forms the optical axis Oax1, is turned on first.

[0141] In step S3, it is determined whether the amount of light received by the light-receiving element 26i, Li, is greater than the first threshold. As mentioned earlier, the first threshold corresponds to the threshold used to determine whether each of the optical axes Oax1 to Oax6 is in a light-shielding state. If the result is yes, the flow proceeds to step S4. On the other hand, if the result is no, the flow proceeds to step S8. In step S8, the safety output (OSSD) is switched to the OFF state without waiting for the display pattern control to be completed. Therefore, it is possible to quickly stop hazardous sources such as press equipment. In addition to switching the safety output (OSSD) to the OFF state in step S8, the display pattern of the OSSD indicator light may also be changed in accordance with the switch to the OFF state of the safety output (OSSD). Steps S3 and S8 are not directly related to the display pattern control. For this reason, steps S3 and S8 are depicted with dashed lines in this figure.

[0142] If a "yes" determination is made in step S3, the amount of light received, Li, is recorded in a register or similar device in step S4.

[0143] In the following step S5, it is determined whether the optical axis is at its final position (i.e., i = imax(6)). If the result is yes, the flow proceeds to step S6. On the other hand, if the result is no, the variable i is incremented by one (++i), and the flow returns to step S1. From here on, steps S1 to S5 are repeated until the result in step S5 is yes.

[0144] If a "yes" determination is made in step S5, step S6 performs a comparison process between the average (=average light received) or minimum (=minimum light received) value of the received light and several threshold values. The comparison process in this step has already been explained in Figures 13 and 14 above. Therefore, a redundant explanation will be omitted.

[0145] In the following step S7, the illumination state (display pattern) of indicator lights 140 and 240 is updated according to the comparison result obtained in step S6. The flow then returns to step S1, and the above series of processes is repeated.

[0146] This diagram is drawn with the understanding that in step S6, a comparison process may be performed between the average value of the received light (=average received light) and multiple thresholds. In other words, the comparison process in step S6 is not performed for each optical axis, but rather after the received light for all optical axes has been recorded.

[0147] However, if a comparison process is performed between the minimum light-receiving amount (= minimum light-receiving amount) and multiple thresholds, step S5 may be omitted. In other words, the comparison process in step S6 may be performed sequentially for each optical axis without waiting for the light-receiving amounts of all optical axes to be recorded.

[0148] For example, if the amount of light received by the first light-receiving element 261 is below the second threshold, it is sufficient to switch to a single green light (i.e., only the indicator light source 170a is lit green) without comparing the amount of light received by each of the other light-receiving elements 262 to 266 with the threshold (see Figure 14). Therefore, subsequent comparison processing can be omitted.

[0149] <Summary> In Figures 9 to 18 above, we proposed a light curtain 1 equipped with a function to switch display patterns according to the light intensity of the optical bearing. To briefly describe this configuration, "In order to form multiple optical axes spaced apart from each other, one of the pair of light-emitting and light-receiving elements forming the multiple optical axes is arranged inside along the longitudinal direction, and the housing has a metal case extending in the longitudinal direction and end members connected to both ends of the metal case, respectively." A cover that transmits light from the light-emitting element and is attached to the housing so as to intersect with the plurality of optical axes, An indicator light, which is a light-diffusing member, is positioned outward along the longitudinal direction from at least one of the outer surfaces of the cover and the housing, or is formed in series with the cover. The enclosure comprises a light source for an indicator light, which is housed inside the enclosure and supplies light for displaying to the indicator light, The light source for the indicator light is controlled to turn on and off in a color corresponding to the operating state of the light curtain and in a display pattern corresponding to the amount of light received by the light receiving element when the light curtain is set to operation indicator light mode.

[0150] <Mounting hardware (resin type)> The resin-type mounting bracket 2A will be described in detail below with reference to Figures 19 to 22. Figures 19 and 20 are perspective and four-view drawings, respectively, of the mounting bracket 2A. Figure 21 shows the mounting bracket 2A attached to the base 3. Figure 22 shows the housing 110 of the floodlight 100 that forms the light curtain 1 attached to the mounting bracket 2A. In each figure, the longitudinal direction of the light curtain 1 is the x-axis, the transverse direction is the y-axis, and the thickness direction (depth direction) is the z-axis. In the following explanation, the housing 110 of the floodlight 100 may be read as the housing 210 of the light receiver 200.

[0151] The mounting fixture 2A corresponds to a jig for attaching the light curtain 1 to the base 3. In this way, a multi-axis photoelectric sensor comprising the mounting fixture 2A and the light curtain 1 attached to the mounting fixture 2A can be installed on the base 3.

[0152] The mounting fixture 2A has, as its main components, a base portion 310, a temporary fixing portion 320, and a permanent fixing portion 330.

[0153] The base portion 310 is a resin member whose rear or side surface is attached to the base 3 and which receives the housing 110 from the front. The base portion 310 has a bottom portion 311 and upright portions 312 and 313. The bottom portion 311 may be formed in a rectangular shape in an xy-plane view. The upright portions 312 and 313 may each be raised in the z-axis direction from both ends of the bottom portion 311 in the y-axis direction. The base portion 310 may be formed in a substantially U-shape with an open front in a yz-plane view, for example.

[0154] The bottom portion 311 is provided with a through hole 311a for passing a screw through in the z-axis direction. The upright portion 312 is provided with a through hole 312a for passing a screw through in the y-axis direction. The base portion 310 is screwed to the base 3 through the through holes 311a or 312a. In other words, the rear or side surface of the base portion 310 attached to the base 3 can be understood as the outer surface of the bottom portion 311 or the upright portion 312, respectively. The through holes 311a and 312a may each be formed in a shape that allows the screw fastening position to be arbitrarily adjusted. For example, the through hole 311a may be formed in an oval shape with the y-axis direction as the longitudinal direction in an xy-plane view. The through hole 312a may also be formed in an oval shape with the z-axis direction as the longitudinal direction in an xz-plane view. Note that multiple through holes 311a and 312a may each be provided.

[0155] The upright portion 313 may be provided with a through hole 313a for inserting a tool such as a hex wrench in the y-axis direction. The through hole 313a may be located opposite the through hole 312a. The through hole 313a may be larger than the through hole 312a. With this configuration, the work of screwing the base portion 310 to the base 3 through the through hole 312a can be made easier.

[0156] A groove 313b may be provided on the outer surface of the upright portion 313, oriented in the x-axis direction, that is, parallel to the longitudinal direction of the light curtain 1. Its technical significance will be described later.

[0157] The temporary fixing portion 320 is a member that temporarily fixes the housing 110 to the base portion 310 by elastic support. The base portion 310 and the temporary fixing portion 320 may be integrally molded resin members. The temporary fixing portion 320 may be provided at both ends of the bottom portion 311 in the x-axis direction. The temporary fixing portion 320 may be a finger-shaped leaf spring bent along the outer shape of the housing 110 so that it can support the housing 110 at at least three points together with the base portion 310.

[0158] The main fixing part 330 is a member that permanently fixes the rotational position around the axis and the vertical position in the longitudinal direction of the housing 110 by pressing the housing 110 and the temporary fixing part 320 inward, respectively, while the housing 110 is temporarily fixed to the base part 310. The main fixing part 330 may be a metal member independent of the base part 310 and the temporary fixing part 320.

[0159] The fixing portion 330 is screwed into the front end of the upright portion 312 by a screw 331 extending in the z-axis direction. Loosening the screw 331 allows the rotational position and vertical position of the housing 110 to be adjusted, respectively. On the other hand, tightening the screw 331 fixes the rotational position and vertical position of the housing 110. The upright portion 312 functions as a receiving member for the screw 331. Therefore, the wall thickness of the upright portion 312 in the y-axis direction is designed to be greater than the wall thickness of the upright portion 313 in the y-axis direction.

[0160] <Installation Procedure (Overview)> Next, an overview of the installation process for the light curtain 1 using the mounting bracket 2A will be explained. First, in the first step, the mounting bracket 2A is screwed to the base 3 as shown in Figure 21. Next, in the second step, the housing 110 is temporarily fixed to the base portion 310 of the mounting bracket 2A as shown in Figure 22. Finally, in the third step, after the rotational position around the axis and the vertical position in the longitudinal direction of the housing 110 are adjusted, the housing 110 is permanently fixed to the base portion 310 of the mounting bracket 2A.

[0161] <Enclosure (metal case)> Figure 23 is a cross-sectional view showing the external shape of the housing 110 (particularly the metal case 111). In this figure, the cross-section is depicted when the housing 110 is cut perpendicularly at any position in the longitudinal direction, i.e., the cross-section zy perpendicular to the longitudinal direction. As shown in this figure, the housing 110 has side wall portions Pa and Pb and arc portions Pc to Pf.

[0162] The side wall portions Pa and Pb are approximately parallel to the optical axis Oax in a zy-section view of the housing 110. The side wall portions Pa and Pb are provided so as to be symmetrical with respect to the optical axis Oax. The arc portions Pc to Pf are each part of the circumference C in a zy-section view of the housing 110. The arc portions Pc and Pd are provided so as to be symmetrical with respect to the optical axis Oax. The arc portions Pe and Pf are provided so as to be symmetrical with respect to the optical axis Oax. The arc portions Pc and Pd are provided in front of the side wall portions Pa and Pb, that is, on the surface side of the housing 110. The arc portions Pe and Pf are provided behind the side wall portions Pa and Pb, that is, on the rear side of the housing 110.

[0163] In this configuration example, the housing 110 is mounted by being directly gripped by the mounting bracket 2A. Therefore, there is no need to form a mounting groove for the bracket on the rear surface of the housing 110. In a typical configuration in which a mounting groove for the bracket is formed on the housing 110, the strength of the rear surface portion where the mounting groove is formed must be increased, which leads to an increase in the size of the housing 110. On the other hand, in this configuration example, the constraint on the strength of the rear surface portion is eliminated, so a smaller size for the housing 110 can be achieved.

[0164] Furthermore, as mentioned earlier, the housing 110 in this configuration example has arc-shaped sections Pc to Pf. Therefore, while the housing 110 is temporarily fixed to the mounting bracket 2A, the rotational position of the housing 110 can be arbitrarily adjusted by rotating the housing 110 around the x-axis. The installation procedure for the housing 110 will be described in detail later.

[0165] Furthermore, a groove 111d may be provided on the outer surface of the housing 110 in the x-axis direction, that is, parallel to the longitudinal direction of the housing 110. The technical significance of this will be described later.

[0166] <Installation process (details)> Figure 24 is a cross-sectional view showing the housing 110 mounted to the mounting bracket 2A with the front facing outwards. This figure can be understood as the α-α cross-section in Figure 22 mentioned earlier.

[0167] First, the temporary fixing procedure for the housing 110 will be explained. The base portion 310 and the temporary fixing portion 320 support the housing 110 at at least three points. For example, when the optical axis Oax is parallel to the z-axis, that is, when the housing 110 is attached to the mounting bracket 2A with the housing facing forward, the inner surfaces of the bottom portion 311 of the base portion 310 can become support portions P1 and P2. Referring to this figure, support portion P1 abuts against the arc portion Pe, and support portion P2 abuts against the arc portion Pf. Also, the inner surface of the finger tip of the temporary fixing portion 320 can become an elastic support portion P0. Referring to this figure, the elastic support portion P0 abuts against the arc portion Pd.

[0168] The elastic support part P0 elastically supports the housing 110 by biasing the arc portion Pf inward. Therefore, the fixing force of the housing 110, that is, the normal force acting between the elastic support part P0 and the arc portion Pd, is lower than when the temporary fixing part 320 does not have spring properties. Consequently, the housing 110 is temporarily fixed in a state where its rotational position around its axis and its vertical position in the longitudinal direction can be adjusted by the frictional force acting between the elastic support part P0 and the arc portion Pd. In other words, the housing 110 can be temporarily fixed simply by fitting it into the mounting fixture 2A without the need for screw tightening.

[0169] Furthermore, the base portion 310 has rotation restricting portions P4 and P5. Rotation restricting portions P4 and P5 are each formed by the inner surface of the base portion 310 facing the housing 110, that is, the inner surface parallel to the x-axis direction, i.e., the inner surface parallel to the front-rear direction of the base portion 310. Referring to the figure, rotation restricting portions P4 and P5 can be formed by the inner surfaces of the upright portions 312 and 313, respectively. Thus, rotation restricting portions P4 and P5 may be provided on both sides of the space that receives the housing 110 so as to face the side walls Pa and Pb of the housing 110.

[0170] The rotation restricting section P4 or P5 contacts the side wall Pa or Pb of the housing 110 while the housing 110 is temporarily fixed to the base section 310, thereby restricting the rotation angle θ of the housing 110 around the x-axis to a predetermined restricting range, for example, -θlim≦θ≦+θlim.

[0171] However, if the restricted range of the rotation angle θ is too narrow, the optical axis adjustment may be insufficient. On the other hand, if the restricted range of the rotation angle θ is too wide, the workability of optical axis adjustment may deteriorate. In light of this trade-off, the restricted range of the rotation angle θ may be set to, for example, within ±30° (-30°≦θ≦+30°). More preferably, it may be within ±20° (-20°≦θ≦+20°). Even more preferably, it may be within ±10° (-10°≦θ<+10°).

[0172] Furthermore, if the rotation angle θ is within the restricted range, for example, if θ = 0° as shown in this figure, the rotation restricting parts P4 and P5 do not come into contact with the side walls Pa and Pb of the housing 110. This state can be understood as a state in which the rotation angle θ is not restricted.

[0173] Figure 25 is a cross-sectional view showing the state in which the rotation of the housing 110 is restricted. As shown in this figure, when the housing 110 is rotated clockwise around the x-axis by an angle of rotation θlim, that is, when θ = +θlim, the rotation restricting part P4 comes into contact with the side wall part Pa. As a result, the housing 110 is unable to rotate further clockwise. In this state, the arc portion Pf of the housing 110 can come into contact not only with the support portion P2 of the base portion 310 but also with the support portion P3. In other words, the base portion 310 and the temporary fixing portion 320 support the housing 110 at five points: the support portions P1 to P3, the rotation restricting part P4, and the elastic support portion P0.

[0174] Furthermore, although not shown again in the diagram, when the housing 110 is rotated counterclockwise around the x-axis by an angle θlim, that is, when θ = -θlim, the rotation restricting part P5 comes into contact with the side wall Pb of the housing 110. As a result, the housing 110 is unable to rotate any further counterclockwise.

[0175] As shown in Figures 24 and 25, grooves 111d and 313b parallel to the longitudinal direction of the light curtain 1 are provided on the outer surface of the housing 110 and the outer surface of the upright portion 313, respectively. These grooves 111d and 313b can serve as indicators to identify whether or not the housing 110 is attached to the mounting bracket 2A with the housing facing forward.

[0176] For example, an operator performing the installation of the light curtain 1 can instantly recognize that the housing 110 is facing the mounting fixture 2A by confirming that the relative positions of grooves 111d and 313b in the z-axis direction coincide, as shown in Figure 24.

[0177] Next, the final fixing procedure for the housing 110 will be explained with reference to Figures 24 and 25. After the rotational and vertical positions of the housing 110 are adjusted, the fixing part 330 is fastened to the base part 310 by tightening the screw 331. As a result, the housing 110 is supported at three points: the support parts P1 and P2 of the base part 310 and the fixing part 330, which does not have spring properties. With this configuration, the housing 110 can be permanently fixed by tightening the screw once. Therefore, the installation of the light curtain 1 becomes easier compared to the conventional method.

[0178] Furthermore, it is preferable that the fixing part 330 be made of metal rather than resin. With this configuration, the fixing part 330 will be less likely to deform when being fixed by screwing or when used at high temperatures. Therefore, the fixing force of the housing 110 can be improved.

[0179] Furthermore, the temporary fixing portion 320 and the permanent fixing portion 330 may be designed so that the pressing direction against the housing 110 is the same. With this configuration, the rotational position and vertical position adjusted during temporary fixing are less likely to shift during permanent fixing.

[0180] In particular, it is desirable that the coefficient of friction of the inner surface of the base portion 310 be greater than the coefficient of friction of the surfaces of the temporary fixing portion 320 and the permanent fixing portion 330, respectively. More specifically, it is preferable that the parts that can become the aforementioned support portions P1 to P3 and rotation restricting portions P4 and P5, namely the bottom portion 311 of the base portion 310 and the inner surfaces of the upright portions 312 and 313, be processed to increase the coefficient of friction, for example, by applying a textured finish.

[0181] In this configuration, the base portion 310 and the housing 110 become less likely to slip, while the temporary fixing portion 320 and the permanent fixing portion 330 and the housing 110 become more likely to slip. As a result, while the permanent fixing portion 330 is pressed against the housing 110 during the permanent fixing process by tightening screws, the housing 110 becomes less likely to rotate around the x-axis. Therefore, the rotation position adjusted during temporary fixing is less likely to shift during permanent fixing.

[0182] <Mounting hardware (metal type)> Next, the metal type mounting bracket 2B will be described in detail with reference to Figures 26 to 29. Figures 26 and 27 are perspective and four-view drawings, respectively, of the mounting bracket 2B. Figure 28 shows the mounting bracket 2B attached to the base 3. Figure 29 shows the housing 110 of the floodlight 100 that forms the light curtain 1 attached to the mounting bracket 2B. In each figure, the longitudinal direction of the light curtain 1 is the x-axis, the transverse direction is the y-axis, and the thickness direction (depth direction) is the z-axis.

[0183] Mounting bracket 2B, like mounting bracket 2A described above, has a base portion 410, a temporary fixing portion 420, and a permanent fixing portion 430 as its main components. Mounting bracket 2B is basically the same configuration as mounting bracket 2A. Therefore, in the description of mounting bracket 2A described above, if the 300-series codes assigned to the components of mounting bracket 2A are read as 400-series codes, the description can be understood as a description of mounting bracket 2B. Accordingly, the following will focus on the characteristic configuration of mounting bracket 2B, in other words, the differences from mounting bracket 2A.

[0184] The mounting bracket 2B has a metal base portion 410 and a temporary fixing portion 420, as well as the main fixing portion 430. For example, the temporary fixing portion 420 may be a metal spring. The metal mounting bracket 2B has superior heat resistance and impact resistance compared to the resin mounting bracket 2A.

[0185] The base portion 410, the temporary fixing portion 420, and the permanent fixing portion 430 may each be made of separate metal components. The temporary fixing portion 420 can be fixed to the base portion 410 with screws 421. The material of the base portion may be aluminum or zinc die-cast. The material of the temporary fixing portion 420 may be SUS304 or phosphor bronze.

[0186] Furthermore, in the resin mounting fixture 2A, it is preferable that the bottom portion 411 of the base portion 410, and the inner surfaces of the upright portions 412 and 413, be processed to increase the coefficient of friction, such as by blasting. With this configuration, the base portion 410 and the housing 110 become less slippery, while the temporary fixing portion 420 and the permanent fixing portion 430 and the housing 110 become more slippery. As a result, while the permanent fixing portion 430 is pressed against the housing 110 during the permanent fixing work by tightening screws, the housing 110 becomes less likely to rotate around the x-axis. Therefore, the rotation position adjusted during temporary fixing is less likely to shift during permanent fixing.

[0187] Furthermore, the surface of the mounting bracket 2B may be painted. This configuration can help prevent scratches on the housing 110.

[0188] <Other variations> Furthermore, the various technical features disclosed herein can be modified in various ways, in addition to the embodiments described above, without departing from the spirit of the technical creation. In other words, the embodiments described above should be considered in all respects to be illustrative and not restrictive, and the technical scope of the present invention should be defined by the claims and understood to include all modifications that fall within the meaning and scope equivalent to the claims. [Explanation of Symbols]

[0189] 1. Light Curtain (Multi-axis Photoelectric Sensor) 2A, 2B mounting hardware 3 bases 100 floodlights 200 Receiver 110, 210 cabinets 111, 211 Metal Case 111a Main Unit 111b 1st protruding strip 111c 2nd protruding strip 111d Groove 112, 113, 212, 213 End caps (end members) 120, 220 cables 130 Front Cover 140, 240 indicator light 150 Bumper section 161-166 Light-emitting elements 261-266 Photodetector 170, 170a / b / c, 270, 270a / b / c light source for indicator light 181, 281 Control circuits 182, 282 Communication Circuits 283 Output Circuit 284 Input Circuit 190, 190x, 190y, 190z circuit board 190a central area 190b End area 191 Light-shielding plate 310, 410 Base section 311, 411 bottom 311a, 411a through hole 312, 313, 412, 413 Standing part 312a, 313a, 412a, 413a through hole 313b, 413b groove 320, 420 Temporary fixing part 421 Screws 330, 430 fixed part 331, 431 screws C circumference Oax, Oax1~Oax6 Optical axis P0 Elastic support P1, P2, P3 support part P4, P5 Rotation Restriction Section Pa, Pb side wall Pc, Pd, Pe, Pf arc section X optical axis intersection area

Claims

1. A mounting device for attaching the housing of a light curtain that forms multiple optical axes along its longitudinal direction to a base, The housing has side walls that are substantially parallel to the optical axis in a cross-sectional view perpendicular to the longitudinal direction, The aforementioned mounting fixture is A base portion whose rear or side is attached to the base and which receives the housing from the front, A temporary fixing part that temporarily fixes the housing to the base part by elastic support, With the housing temporarily fixed to the base portion, the main fixing portion permanently fixes the rotational position of the housing around its axis and the vertical position in the longitudinal direction by pressing the housing, Equipped with, The base portion is a mounting device having a rotation restricting portion that, when the housing is temporarily fixed to the base portion, contacts the side wall portion of the housing to restrict the rotation of the housing around its axis to a predetermined restricted range.

2. The mounting device according to claim 1, wherein the rotation restricting portion is formed by the inner surface of the base portion facing the housing, which is parallel to the front-rear direction of the base portion, and is provided on both sides of the space for receiving the housing so as to face the side wall portion of the housing.

3. The mounting device according to claim 1, wherein a groove parallel to the longitudinal direction is provided on the outer surface of the base portion.

4. The housing has an arc portion that forms part of the circumference in a cross-sectional view perpendicular to the longitudinal direction, The mounting device according to claim 1, wherein the base portion has a plurality of support portions that contact the arc portion of the housing together with the temporary fixing portion.

5. The mounting device according to claim 4, wherein the coefficient of friction of each of the plurality of support parts is greater than the coefficient of friction of the surface of the temporary fixing part and the permanent fixing part, respectively.

6. The mounting device according to claim 1, wherein the temporary fixing portion and the permanent fixing portion are pressed in the same direction relative to the housing.

7. The mounting device according to claim 1, wherein the base portion and the temporary fixing portion are integrally molded resin members, and the permanent fixing portion is a metal member independent of the base portion and the temporary fixing portion.

8. The mounting device according to claim 1, wherein the base portion, the temporary fixing portion, and the permanent fixing portion are each separate metal members.

9. The mounting fixture according to claim 1, wherein the aforementioned regulatory range is within ±30°.

10. A mounting device for attaching the housing of a light curtain that forms multiple optical axes along its longitudinal direction to a base, The aforementioned mounting fixture is A base portion whose rear or side is attached to the base and which receives the housing from the front, A temporary fixing part that temporarily fixes the housing to the base part by elastic support, With the housing temporarily fixed to the base portion, the main fixing portion permanently fixes the rotational position of the housing around its axis and the vertical position in the longitudinal direction by pressing the housing, Equipped with, The aforementioned temporary fixing part is a metal spring, which is a mounting device.

11. A mounting method for attaching the housing of the light curtain to the base using a mounting fixture according to any one of claims 1 to 10, The steps include screwing the mounting fixture to the base, The steps include temporarily fixing the housing to the base portion of the mounting fixture, The steps include: permanently fixing the housing, whose rotational position around its axis and vertical position in the longitudinal direction have been adjusted, to the base portion of the mounting fixture; A mounting method that includes the following features.

12. A mounting fixture according to any one of claims 1 to 10, The light curtain attached to the mounting fixture, A multi-optical-axis photoelectric sensor equipped with the following features.

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