JP3862743B2 - Multi-axis photoelectric sensor - Google Patents

Description

  The present invention relates to a multi-optical axis photoelectric sensor.

  The multi-optical axis photoelectric sensor includes a projector and a light receiver that are arranged to face each other, and forms a light curtain between the light projector and the light receiver. For example, when a part of the human body blocks the light curtain, the multi-optical axis photoelectric sensor emits a light blocking signal, thereby taking safety measures such as stopping the operation of the mechanical system located in the space partitioned by the light curtain.

Patent Document 1 discloses a multi-optical axis photoelectric sensor containing a plurality of optical elements arranged in a line at equal intervals from one end to the other end of an elongated sensor case. In this multi-optical axis photoelectric sensor, a front cover is fixed to a light projecting surface or a light receiving surface on a flange defining the light projecting window or the light receiving window via an adhesive. Moreover, this patent document 1 forms the some snap fit which protrudes from a front cover integrally with a front cover, and this snap fit is engaged with the uneven | corrugated | grooved part of the inner wall surface of a sensor case (snap fitting), It has been proposed that the front cover be mounted on the sensor case without using it.
Japanese Patent Laid-Open No. 10-74432

Regarding the mounting of the front cover, Patent Document 1 discloses a first method of fixing the front cover using an adhesive as described above, and a first method of fixing the front cover by snap fitting using a snap integrally formed with the front cover . 2 of how not disclose.

Therefore, an object of the present invention is to provide a multi-optical axis photoelectric sensor that can lock the front cover while suppressing the complexity of the shape of the front cover .

According to the present invention, such a technical problem is
A plurality of optical elements arranged in a line at equal intervals from one end to the other end of the long sensor case, and a light projecting window or a light receiving window formed on the light projecting surface or the light receiving surface of the sensor case. In a multi-optical axis photoelectric sensor having a front cover fixed through a defining flange,
Together with the sensor case is a hollow pillar shape which is open at both ends, consists of a main body case that the optical element is arranged, the end casing portion which is connected to both ends of the body case,
Said end portion case, the opened one end of the side to be connected to the main case, with the shape of the open end face of the end edge shapes and are substantially the same and the other end of the main body case is closed, said end The optical element is arranged in the part case ,
The end case is further provided with a connector opening for receiving an external connector of a cable with an external connector, and a recess for receiving the external connector inserted into the connector opening.
The multi-optical axis photoelectric sensor further comprises:
Having a pressing member made of a metal plate material crossing the longitudinal end of the front cover;
The pressing member includes a flat main body traversing the front cover, and a pair of legs depending downward from a longitudinal end of the main body;
Presser leg member by inserting the elongated opening formed in the end casing, the multi-optical axis photoelectric sensor, characterized in that the presser member is releasably snap-fit before Kitan portion case Achieved by providing.

That is, in the present invention is to provide a pressing member that is snapped to the end casing portion, characterized in that it is adapted to engage the longitudinal ends of the front cover in the pressing member.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a multi-optical axis photoelectric sensor 1 according to an embodiment. The multi-optical axis photoelectric sensor 1 includes a projector and a light receiver that are paired with each other. Since the light projector and the light receiver have substantially the same external shape, the following multi-optical axis photoelectric sensor 1 is used. It is to be understood that the explanation of is a description without distinguishing between a projector and a light receiver.

  The multi-optical axis photoelectric sensor 1 includes a main body case 2 made of an extruded aluminum material, and an end case 3 of a plastic molded product or a zinc or aluminum die-cast molded product disposed at both ends of the main body case 2. A slender straight outer shape is formed, and light projecting elements or light receiving elements are arranged in the main body case 2 and the end case 3 at equal intervals along the longitudinal direction. The light projecting surface or light receiving surface 4 of the multi-optical axis photoelectric sensor 1 is constituted by a front cover, through which the light beam is emitted from the light projector or the light beam from the light projector is incident on the light receiver. .

  The connector opening 5 opens in the optical axis direction, that is, toward the front cover 4 side, and by pushing the external connector 6 toward the back side of the multi-optical axis photoelectric sensor 1 as shown in FIG. A connector can be connected, and this external connector 6 can be used to connect a control device (not shown) or an adjacent multi-optical axis photoelectric sensor via a cable 7.

  FIG. 4 shows the optical system unit 10 built in the multi-optical axis photoelectric sensor 1. The optical system unit 10 has a plurality of element holders 11 arranged at equal intervals, and the element holder 11 has a cylindrical passage 12 formed therein. An optical element 13, that is, a light projecting element or a light receiving element is detachably fitted at the base end of the element holder 11, and the optical element 13 faces the cylindrical passage 12 through a first small circular opening 14.

  At the front end of the element holder 11, a plastic lens plate 16 integrally formed with two adjacent light projecting or light receiving lenses 15 is disposed. For example, in the case of a projector, the light emitted from the light projecting element 13 is The element holder 11 passes through an internal passage 12 having a circular cross section, and then passes through a lens 15 into a light beam that is substantially a bundle of parallel rays. Conversely, in the case of a light receiver, the light beam is converged by the lens 15 and enters the light receiving element 13 through the first small circular opening 14.

  The optical system unit 10 is a plastic molded product, and a light shielding wall 17 is provided in the cylindrical internal passage 12, and the light shielding wall 17 is integrally formed with the main body of the optical system unit 10. A second relatively large circular opening 18 is formed in the central portion of the light shielding wall 17.

  The inner wall of the cylindrical inner passage 12 of the element holder 11 is preferably coated with a paint that can reduce the ability of the inner wall to reflect light, such as a black paint. Of course, a pigment may be included in the plastic material of the optical system unit 10 so that the optical system unit 10 itself has a dark color such as black.

  The light shielding wall 17 is formed in the longitudinal direction, that is, an intermediate portion in the optical axis direction with respect to the cylindrical internal passage 12, and thereby, the single light shielding wall 17 causes a malfunction due to stray light at a level that does not impede practical use. It can be effectively prevented. The effects of this single light shielding wall 17 are as follows. (1) Since the amount of light regularly reflected by the wall of the internal passage 12 of the element holder 11 is attenuated, the amount of light is attenuated. No; (2) It is assumed that the light diffusely reflected by the wall of the internal passage 12 of the element holder 11 is attenuated, so that there is no influence even if this light goes outside. That is, the function of the light shielding wall 17 of the internal passage 12 is to prevent the light that has been regularly reflected once by the wall 9 of the internal passage 12 from reaching the light projecting lens 15 in the case of a projector, for example.

  The internal passage 12 of the optical system unit 10 according to the embodiment has a cylindrical shape. However, if the internal passage 12 has a circular passage shape that is tapered toward the lens 15, the light shielding wall 17 has a passage length of the internal passage 12. What is necessary is just to install in the location close | similar to the lens 15 side rather than the 1/2 location. On the contrary, if the internal passage 12 has a circular cross-sectional shape extending toward the lens 15, the light shielding wall 17 is closer to the optical element 13 side than the half of the passage length of the internal passage 12. Should be installed.

  The optical system unit 10 can be connected to an extension unit (not shown) at its end in accordance with the number of optical axes of the multi-optical axis photoelectric sensor 1. Have substantially the same structure.

  The optical system unit 10 is provided with a substrate 19 extending in the longitudinal direction along the unit 10 on the back side. The substrate 19 includes a power supply circuit, a control circuit, a light emitting circuit (light receiving circuit), a communication circuit, and the like. Incorporated.

  The optical system unit 10 is inserted into the main body case 2 from the one end opening of the main body case 2 together with the substrate 19. As can be understood from FIG. 3, the main body case 2 has a shape in which one side surface is opened. That is, the main body case 2 has a pair of side walls 20, 20 facing each other, and has a U-shaped cross section in which the ends of the side walls 20, 20 are connected by the back wall 21.

  The main body case 2 is shorter than the total length of the optical system unit 10 or the optical system unit 10 and the extension unit. More specifically, when the main body case 2 inserts the optical system unit 10 or a connection body between the optical system unit 10 and the extension unit, among the optical axes included in these units, elements for two optical axes at both ends are included. The holder 11 is designed to protrude outward from the end of the main body case 2.

  Of the optical system unit 10 or the connected body of the optical system unit 10 and the extension unit, a portion protruding to the outside from both ends of the main body case 2 is surrounded by an end case 3 shown in an enlarged manner in FIG.

  The end case 3 has a first recess 24 on one side wall 23 so that when the cube-shaped external connector 6 is received, the end case 3 has substantially the same external shape as the main body case 2. And a second recess 25 through which the cable 7 extending from the external connector 6 can pass. The end case 3 further has a connector opening 26 through which the external connector 6 can enter, facing the first recess 24, and the connector is connected through the connector opening 26.

  One end of the end case 3 is closed and the other end is opened. The end case 3 is connected to the main unit 2 by abutting the open end with the end of the main unit 2.

  The cross-sectional shape of the end case 3 will be described. The end case 3 includes a pair of side walls 23, 23 and a back wall 28 that connects the ends of the side walls 23, 23. When the end case 3 and the main body case 2 are connected, they are flush with the walls 20 and 21 of the main body case 2.

  In addition, the end case 3 has a flat front flange 29 that faces the back wall 28, and the front flange 29 is formed with a slit 30 that opens to the open end side of the end case 3. 30 extends straight toward the closed end of the end case 3, and the slit 30 constitutes a window through which the light beam passes.

  The connection between the end case 3 and the main body case 2 and the attachment of the front cover 4 will be described. As can be understood from FIG. 3, the main body case 2 is formed with three screw receiving holes 32 opened at both ends. . Correspondingly, the end case 3 is formed with three holes 34 through which the screws 33 (only the screw axis is shown in FIG. 6 to avoid confusion in the drawing) are inserted. The end case 3 and the main body case 2 are screwed so as to be detachable in a state where their ends are butted together via a seal packing 36 in which a portion corresponding to the slit 30 is cut out.

  Reference numeral 38 seen in FIG. 6 indicates an additional holding member for constituting a seat crossing the front cover 4 in order to fix the front cover 4. FIG. 7 is inverted to clarify the shape of the pressing member 38. The pressing member 38 is made of a metal plate material, and is a long flat main body 39, a pair of left and right legs 40 depending downward from both ends of the main body 39, and the front end of the pressing member 38, that is, the main body case 2 side. And left and right legs 40 have projecting pieces 42 formed by cutting and raising.

  The pressing member 38 is disposed at the open end of the end case 3. In order to position the pressing member 38, the pressing member 38 is positioned at the boundary between the front flange 29 and the side walls 28 of the end case 3. An opening 44 (FIG. 6) is formed for receiving the 38 legs 40.

  FIG. 6 shows a state before the pressing member 38 is mounted. The pressing member 38 is detachably integrated with the end case 3 by snap-fitting the leg 40 into the opening 44 of the end case 3 by the projecting piece 42.

  FIG. 8 shows the front cover 4. The front cover 4 includes a first front cover 50 that is slightly longer than the entire length of the main body case 2 and a second front cover 51 that is slightly shorter than the entire length of the end case 3, and these first and second front covers. Both 50 and 51 are made of a light transmissive plastic material.

  As can be seen from FIG. 3, the main body case 2 is formed with inner flanges 53 extending in the longitudinal direction at the front side edges of the both side walls 20, and the inner flanges 53 serve as mounting seats for the first front cover 50. It is composed. Reference numeral 54 shown in the figure indicates a guide groove for receiving the left and right protrusions of the optical system unit 10, and when the optical system unit 10 is inserted into the main body case 2 and the end case 3 by the guide groove 54. The optical system unit 10 is guided and the optical system unit 10 is positioned.

  Although not shown, the optical system unit 10 has a projecting seat at a portion corresponding to the open end of the end case 3 at the center of the front surface, as will be described later with reference to FIG. This projecting seat portion enters the slit 30 of the end case 3 and forms a common plane with the front flange 29.

  When attaching the first and second front covers 50, 51, first, the left and right inner flanges 53 of the main body case 2 and the front flange 29 of the end case 3 are continuously covered with an adhesive seal material. The sealing material is applied continuously so as to cross the open end of the end case 3. Next, positioning is performed while pressing the first and second front covers 50 and 51. Thereby, the extension part 50a of the first front cover 50 is located across the boundary between the main body case 2 and the end case 3, and the end part of the extension part 50a is continuous across the end case 3. It is sealed by a sealing material extending to

  Next, when the pressing member 38 is snapped onto the open end portion of the end case 3, the end portion of the first front cover 50 is pressed downward by the pressing member 38, and both end portions of the first front cover 50 are pressed. Is mechanically fixed by a pressing member 38.

  As a modification, as shown in FIG. 9, the sensor case 101 of the multi-optical axis photoelectric sensor 100 includes a main body case 102 and an end case 103 connected to the end of the main body case 102. The plurality of optical elements arranged at equal intervals and in one row, that is, the optical axis 104, avoids not only the connecting portion between the main body case 102 and the end case 103 but also the end case as well as the main body case 102 as described above. Also arranged in the part case 103.

  The main body case 102 has an exemplary flat first flange 105 constituting a seal seat surface on the front surface thereof. The first flange 105 has a first opening 106 positioned corresponding to the optical axis 104. Is formed. In the example shown in the figure, the first opening 106 is formed by a slit extending in the longitudinal direction of the main body case 102. As described above, as disclosed in JP-A-10-74432, each optical axis You may comprise by the window independent for every 104 or every several optical axis 104 grouped.

  Similarly, the end case 103 has, on the front surface thereof, an exemplary flat second flange 108 constituting a seal seat surface, and the second flange 108 is positioned corresponding to the optical axis 104. Two openings 109 are formed. The second opening 109 may be configured by an independent window for each optical axis as shown in FIG. 10, or may be a window arranged so as to include two optical axes as shown in FIG. Alternatively, as shown in FIG. 12, the slit may extend to the open end of the end case 103.

  Returning to FIG. 9, the front cover 110 disposed on the front surface of the sensor case 101 includes a first front cover 111 corresponding to the main body case 102 and a second front cover 112 corresponding to the end case 103. ing.

  Thus, the sensor case 101 is divided into three parts 102, 103, 103, and the front cover 110 disposed on the front surface of the sensor case 101 is divided into three parts accordingly. The total length of the front cover can be shortened as compared with a configuration including two front covers, and thereby the influence of the thermal expansion difference between the sensor case 101 and the front cover 111 can be reduced.

  When the distance between the closed end of the end case and the optical element closest to the end case is short, it is often necessary to cover the front surface of the sensor with a single front cover that can cover the entire longitudinal direction of the multi-optical axis photoelectric sensor. In order to properly cover the optical axes located at both ends of the optical axis photoelectric sensor, high dimensional accuracy and high assembly accuracy of the front cover are required. On the other hand, by dividing the front cover as in the present invention, covering the front surface of the multi-optical axis photoelectric sensor with a plurality of front covers and positioning the butting edge between adjacent front covers between the optical axes, The required accuracy for the front cover can be reduced.

  In the modification, the first front cover 111 or the second front cover 112 has an extension 120 that extends beyond the boundary between the main body case 102 and the end case 103 where it is relatively difficult to ensure sealing performance. Have.

  In the example of FIG. 9, the extension portion 120 is provided in the first front cover 111, and the first front cover 111 has entered the end case 103, but the second end cover 103 has a second end. When the opening 109 is constituted by one window including the two optical axes 104, and the second flange 108 constituting the seal seat surface is continuous in the transverse direction on the open end side of the end case 103 ( 11), a sealing material is continuously applied to the second flange 108 in a direction crossing the end case 103, and the extension 120 of the first front cover 111 is bonded and / or sealed with the sealing material, Preferably, the extension 120 and the end of the second front cover 112 adjacent thereto may be bonded and / or sealed.

  Further, as shown in FIG. 13, the first opening 106 of the main body case 102 is configured by a slit that is continuous in the longitudinal direction from one end to the other end of the main body case 102, and the second opening of the end case 103 is provided. The end portion of the main body case 102 and / or the end portion of the end case 103 is notched by the slit, as in the case where the opening 109 is configured by a slit extending toward the open end of the end case 103. 14, the optical system unit 121 including a plurality of elements is provided in the slits (first and second openings 106 and 109) of the main body case 102 and / or the end case 103. Protruding seats 122 (see also FIG. 15) may be provided to enter and fill the slits and make a plane substantially the same as the first or second flange 105, 108 as a seal seat. . The optical system unit 121 is held at a predetermined position by a guide groove 123 extending in the longitudinal direction of the main body case 102. The projecting seat 122 may extend continuously in the longitudinal direction of the optical system unit 121, but at least a portion where the sealing material 124 is applied may be provided partially.

  The extension 120 is glued and / or sealed through a series of seals 124 across the end of the first front cover extension 120 and the adjacent second front cover 112, including the protruding seat 122. The sealing material 124 may be continuous with the first and second sealing materials 125 and 126 applied to the first flange 105 of the main body case 102 and the second flange 108 of the end case 103. Most preferably (FIGS. 16 and 17). Note that the first and second sealing materials 125 and 126 preferably have adhesiveness.

  The end of the first front cover 111 that is longer than the second front cover 112 is a pressing member 128 (FIG. 17) that is snapped into the main body case 102 or the end case 103 and crosses the end of the first front cover 111. It is preferable that the end of the first front cover 111 is pushed down. In particular, when the extension portion 120 is provided on the first front cover 111, the end of the extension portion 120 is most preferably pushed down by the pressing member 128. preferable.

  Further, as shown in FIG. 13, a seal member 128 having a shape that allows passage of the optical system unit 121 by notching a portion corresponding to the slit on the abutting surface of the main body case 102 and the end case 103. It is preferable to interpose.

It is a perspective view of the multi-optical axis photoelectric sensor of an Example. The end part of the multi-optical axis photoelectric sensor of an Example is shown in figure, It is the fragmentary figure for demonstrating the state which connected the external connector. It is an end view of the main body case of the multi-optical axis photoelectric sensor of an Example. It is sectional drawing of the optical system unit incorporated in the multi-optical axis photoelectric sensor of an Example. It is a perspective view of the edge part case of the multi-optical axis photoelectric sensor of an Example. FIG. 4 is an exploded perspective view of an end case and a member related thereto in an exploded manner showing a pressing member incorporated in an end case of the multi-optical axis photoelectric sensor of the embodiment and a seal member interposed between the main body case and FIG. is there. It is a perspective view of a pressing member. It is a figure for demonstrating that a front cover is comprised from the 1st front cover and the 2nd front cover arrange | positioned at the both ends. It is a front view of the multi-optical axis photoelectric sensor for demonstrating the outline | summary of embodiment of this invention. It is a perspective view of an example of the end case of the multi-optical axis photoelectric sensor illustrated in an embodiment. It is a perspective view of the other example of the edge part case of the multi-optical axis photoelectric sensor illustrated in embodiment. It is a perspective view of another example of the end case of the multi-optical axis photoelectric sensor exemplified in the embodiment. It is a disassembled perspective view of the edge part of the multi-optical axis photoelectric sensor for demonstrating the outline | summary of embodiment. It is a fragmentary perspective view of the outline | summary of the optical system unit incorporated in a multi-optical axis photoelectric sensor as an example of embodiment. It is sectional drawing cut | disconnected along the X15-X15 line | wire of FIG. It is sectional drawing cut | disconnected along the X16-X16 line | wire of FIG. It is a figure for demonstrating the outline | summary of the edge part of the multi-optical axis photoelectric sensor illustrated in embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multi-optical axis photoelectric sensor 2 Main body case 3 End case 4 Front cover 29 Front wall of end case 36 Sealing packing 38 Holding member 50 1st front cover 51 2nd front cover 53 Inside formed in the side wall of main body case Flange

Claims (4)

A plurality of optical elements arranged in a line at equal intervals from one end to the other end of the long sensor case, and a light projecting window or a light receiving window formed on the light projecting surface or the light receiving surface of the sensor case. In a multi-optical axis photoelectric sensor having a front cover fixed through a defining flange,
Together with the sensor case is a hollow pillar shape which is open at both ends, consists of a main body case that the optical element is arranged, the end casing portion which is connected to both ends of the body case,
Said end portion case, the opened one end of the side to be connected to the main case, with the shape of the open end face of the end edge shapes and are substantially the same and the other end of the main body case is closed, said end The optical element is arranged in the part case ,
The end case is further provided with a connector opening for receiving an external connector of a cable with an external connector, and a recess for receiving the external connector inserted into the connector opening.
The multi-optical axis photoelectric sensor further comprises:
Having a pressing member made of a metal plate material crossing the longitudinal end of the front cover;
The pressing member includes a flat main body traversing the front cover, and a pair of legs depending downward from a longitudinal end of the main body;
Presser leg member by inserting the elongated opening formed in said end case, the multi-optical axis photoelectric sensor, characterized in that the presser member is releasably snap-fit before Kitan unit case. The multi-optical axis photoelectric sensor of Claim 1 which can connect the adjacent multi-optical axis photoelectric sensor via the said cable with an external connector. Protrude outward from both side walls said flange of said end portion case, the boundary between the side walls and the flange of the end portion case, the elongated opening for receiving the legs of the pressing member in the longitudinal direction of the sensor casing The multi-optical axis photoelectric sensor according to claim 1 or 2, which extends along the same line. When the external connector is inserted into the connector opening, the external connector fills the recess, and the end case including the external connector has substantially the same cross-sectional shape as that of the main body case. The multi-optical axis photoelectric sensor as described in any one of Claims 1-3.

Images