JP2005321198A - Multi-optical axis photoelectric sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-optical axis photoelectric sensor capable of securing easily sealability of an end case, while suppressing an influence of the thermal expansion difference between a front cover and a sensor case. <P>SOLUTION: This sensor is connected to the end of a body case 2 through a seal member 23 having the substantially same ring shape as the shape of the open end of the end case 3. The end case 3 has a front face flange 27, and light from a four-optical axis optical element passes through a window 28 of the front face flange 27. The front cover is constituted of the first cover 4a corresponding to the body case 2 and the second cover 4b corresponding to the end case 3, and a metal belt member, for example, is interposed into a butting part between the end face of the first front cover 4a and the end face of the second front cover 4b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

  The multi-optical axis photoelectric sensor includes a light projector and a light receiver that are arranged to face each other, and a multi-optical axis light curtain is formed between the light projector and the light receiver. For example, when a part of the human body blocks at least one optical axis of the multi-optical axis, the multi-optical axis photoelectric sensor generates a light shielding signal, thereby stopping the operation of the mechanical system located in the space partitioned by the light curtain. Safety measures are taken.

Patent Document 1 makes a proposal regarding the sealing performance of the case of the multi-optical axis photoelectric sensor. That is, in this publication, when a light-transmitting front cover is bonded to the front surface of the sensor case in which the lid member is screwed to the opening at both ends, that is, the surface where the projector and the light receiver face each other, In order to prevent a gap between the front cover and the lid member due to a difference in thermal expansion between the front cover and the lid member, a flat wall is provided on the front surface of the sensor case, and the front wall of the sensor case is provided. It proposes to form a window or opening through which a plurality of adjacent light beams can pass, and to join the flat wall and the front cover with an adhesive.
Japanese Patent Laid-Open No. 10-74432

  By the way, when the sensor case of the multi-optical axis photoelectric sensor is composed of a main body case and an end case, and the optical element is arranged not only in the main body case but also in the end case, the main body case and the end case When the front cover that extends over is provided, the above-described problem due to the difference in thermal expansion with the sensor case occurs.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reduce the influence of thermal expansion difference between the front cover and the sensor case when the sensor case of the multi-optical axis photoelectric sensor is composed of a main body case and an end case. It is to provide an axial photoelectric sensor.

  Another object of the present invention is to provide an end case with an optical element, and when the end case also has one or more optical axes, it is easy to ensure the sealing performance of the end case. An optical axis photoelectric sensor is provided.

According to the present invention, such a technical problem is
In a multi-optical axis photoelectric sensor comprising a plurality of optical elements arranged in a row spaced apart from each other in a case,
An optical system unit extending from one end of the multi-optical axis photoelectric sensor to the other end;
An element holder that constitutes a part of the optical system unit and holds the plurality of optical elements apart from each other;
A main body case that constitutes a central portion of the case of the multi-optical axis photoelectric sensor and that is open at both ends;
An end case connected to the end of the body case, one end open and the other end closed;
A light transmissive first front cover provided on the front surface of the main body case;
A light transmissive second front cover provided on the front surface of the end case;
This is achieved by providing a multi-optical axis photoelectric sensor having a belt-like member interposed between the first and second front covers and attached to the end case.

  That is, in the present invention, the sensor case is constituted by a total of three parts, that is, the main body case and the end cases connected to both ends thereof, and the front cover is applied to the main body case in accordance with this. The first front cover and the second front cover applied to the end case are divided into three parts, and a belt-like member is interposed between the first front cover and the second front cover. Therefore, compared with the conventional case where the front of the sensor case is covered with a single front cover, the total length of the front cover can be shortened, and this affects the difference in thermal expansion between the sensor case and the front cover. Can be reduced. Further, in the present invention, since the band-shaped member is interposed between the first and second front covers, the thermal expansion of the first and second front covers is absorbed by the bending deformation of the band-shaped member. be able to.

  When the distance between the closed end of the end case and the optical element closest to the closed end is short, it is not possible 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 positioned at both ends of the multi-optical axis photoelectric sensor, high dimensional accuracy and high assembly accuracy of the front cover are required. In contrast, the required accuracy for the front cover can be reduced by dividing the front cover as in the present invention and covering the front surface of the multi-optical axis photoelectric sensor with a plurality of front covers.

The above mentioned other objects of the invention are in accordance with the invention.
In a multi-optical axis photoelectric sensor comprising a plurality of optical elements arranged in a row apart from each other, and creating a multi-optical axis light curtain with the plurality of optical elements,
An optical system unit extending from one end to the other end of the multi-optical axis photoelectric sensor and holding the plurality of optical elements in a separated state;
A body case for opening both ends and surrounding a central portion of the optical system unit;
An end case for opening one end and closing the other end, and connecting an end on the open side to the end of the main body case to surround the end of the optical system unit;
A light-transmissive front cover disposed on the front surface of the end case;
The end case has a front flange provided with a window through which an optical axis located at an end of the optical system unit can pass,
This is achieved by providing a multi-optical axis photoelectric sensor in which the front cover is locked to the end case through the sealing material.

  That is, according to the present invention, regarding the sealing performance related to the window through which the optical axis of the end case can pass, the entire periphery of the window is surrounded by the front flange, and the entire periphery of the window is surrounded by the front flange. Since the front cover is locked to the end case through the continuous sealing material that can be formed, the sealing performance with respect to the window of the end case can be ensured. If the end case has a slim shape, it is preferable to assemble the lens, which is a component of the optical system unit, after inserting the optical system unit into the end case. It becomes easy to insert in the part case.

  As a specific method for securing the sealing performance by the sealing material, the sealing material may be crushed in the optical axis direction on the back surface of the front cover. A rib that continuously extends on the back surface of the front cover is provided so as to face the stepped peripheral wall that forms the outline of the formed window, and the sealing material is disposed in close contact with the rib and the peripheral wall. You may make it make it.

  The body case and the end case described above are preferably made of a material having excellent heat conduction characteristics such as aluminum and zinc. Moreover, even if it exists in a strip | belt-shaped member, it is preferable to be made from the material which can be slightly bent and deformed like a metal plate.

  The first and second front covers are preferably attached to the main body case and the end case using a double-sided adhesive tape, whereby the first and second front covers are peeled off from the main body case and the end case by thermal expansion. Can be prevented from falling off.

  In particular, the second front cover that covers the front surface of the end case with the closed end is preferably mechanically coupled to the end case, for example, by engaging a claw, in order to prevent falling off, For example, by setting the direction in which the claw protrudes in the width direction of the end case, the second front cover is connected to the end case so as to be displaceable in the longitudinal direction, thereby preventing the second front cover from falling off. Is preferred.

  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 should be understood that the explanation of the above is described without distinguishing between the projector and the light receiver. Moreover, although the multi-optical axis photoelectric sensor 1 has a light projecting element or a light receiving element incorporated at equal intervals from the one end to the other end with a small separation distance (10 to 20 mm pitch), those skilled in the art Slim as you can see. Therefore, it should be understood that the various technologies employed in the embodiments are basically directed to efficiently housing various components in a limited space within the multi-optical axis photoelectric sensor 1. .

  The multi-optical axis photoelectric sensor 1 is composed of a body case 2 made of an extruded material of aluminum and open at both ends, and a plastic molded product or a zinc or aluminum die-cast molded product disposed at both ends of the body case 2 and The end case 3 having one end open and the other end closed has a slender straight outer shape. The main body case 2 and the end case 3 are arranged at equal intervals along the longitudinal direction. A light receiving element is arranged.

  The light projecting surface or light receiving surface 4 of the multi-optical axis photoelectric sensor 1 is constituted by a light-transmitting front cover, through which the light beam is emitted from the light projector or the light beam from the light projector is sent to the light receiver. Incident light. The front cover 4 includes a first cover 4 a substantially corresponding to the main body case 2 and a second cover 4 b substantially corresponding to the end case 3, and these first and second front covers. 4a and 4b are separate parts.

  The end case 3 has a connector opening 5, and this connector opening 5 opens from the back side to the front side of the end case 3, and as shown in FIG. A connector can be connected by pushing toward the back side of the multi-optical axis photoelectric sensor 1, and the external connector 6 is used to connect to a control device (not shown) or an adjacent multi-optical axis photoelectric sensor via a cable 7. be able to.

  FIG. 3 shows the multi-optical axis photoelectric sensor 1 during assembly, and the front cover 4 is not shown in FIG.

  The multi-optical axis photoelectric sensor 1 has an optical system unit 8 accommodated in the main body case 2 and the end case 3, and the optical system unit 8 extends from one end to the other end of the multi-optical axis photoelectric sensor 1. It extends.

  The optical system unit 8 includes an element holder 9 of a plastic molded product forming the skeleton. The element holder 9 has a plurality of light guide paths 10 that open to the front surface, and the light guide paths 10 are arranged at equal intervals in the longitudinal direction of the multi-optical axis photoelectric sensor 1. On the back surface of the element holder 9, an optical element (light projecting element or light receiving element) is mounted for each light guide path 10.

  FIG. 4 is an end view of the main body case 2. The optical system unit 8 is inserted into the main body case 2 from one end opening of the main body case 2 together with one or a plurality of substrates 12, and a portion protruding from the main body case 2 is covered with the end case 3. The substrate 12 includes a power supply circuit, a control circuit, a light emitting circuit (light receiving circuit), a communication circuit, and the like.

  As can be understood from FIG. 4, the main body case 2 has a shape in which one side surface is opened (opened upward in FIG. 4). That is, the main body case 2 has a pair of side walls 2a, 2a facing each other, and has a U-shaped cross section in which the ends of the side walls 2a, 2a are connected by the back wall 2b.

  The main body case 2 has an inner flange 13 extending in the longitudinal direction along the front edge of each side wall 2a, and the pair of inner flanges 13 constitutes a mounting seat for the first front cover 4a. The body case 2 has a pair of inner flanges 13, 13 having a slit 14 formed between them. Light can enter and exit through the slit 14.

  Reference numeral 15 shown in FIG. 4 indicates a guide groove that can receive the protrusions 8 a and 8 b protruding outward from both sides in the width direction of the optical system unit 8, and the guide grooves 15 and 15 are longitudinal directions of the main body case 2. It extends continuously in the direction. The optical system unit 8 can be inserted into the main body case 2 while being guided by the guide groove 15.

  Returning to FIG. 3, reference numeral 16 shown in FIG. 3 denotes a lens unit. The lens unit 16 is composed of a plastic molded product in which four adjacent lenses 17 are molded on a single plate. The lens unit 16 is assembled after the optical system unit 8 is accommodated in the main body case 2 and the end case 3.

  One end wall 3 of the end case 3 is integrated with the external connector 6 and has substantially the same external shape as the main unit 2 when the cubic external connector 6 is received (FIG. 2). And a second recess 21 through which the cable 7 extending from the external connector 6 can pass (FIGS. 5 and 6). The end case 3 further has a connector opening 22 (FIG. 12) through which the external connector 6 can enter, facing the first recess 20, and the connector through the connector opening 22, that is, the external connector insertion port. A connection is made.

  The end case 3 has one end closed and the other end open. As can be understood from FIG. 7, the open end of the end case 3 is substantially the same as the shape of the open end of the end case 3. They can be connected by butting against the end of the main body case 2 via a ring-shaped seal member 23, and the two pins 2 and 3 are relatively positioned by positioning pins 24 (FIG. 6). The cross-sectional shape of the butted portion of the end case 3 is substantially the same as the cross-sectional shape of the main body case 2, thereby connecting the end case 3 to both ends of the main case 2 using three screws 25. In some cases, there is no step between the main body case 2 and the end case 3 and both ends are closed.

  Referring to FIG. 7, the end case 3 has a front flange 27 extending in the longitudinal direction from one end to the other end. The front flange 27 is formed with an elongated opening or window 28 through which light can pass. Yes. That is, the entire circumference of the window 28 is surrounded by the front flange 27. The window 28 extends straight in the longitudinal direction of the end case 3, and light from a four-optical axis optical element accommodated in the end case 3 can pass through the window 28.

  In order to allow the optical axis to pass through the window 28 surrounded by the front flange 27 as described above, by adopting a configuration in which the lens unit 16 is assembled after the optical system unit 8 is inserted into the end case 3. It can be realized for the first time.

  An end front cover, that is, a second front cover 4b disposed on the front surface of the end case 3, includes a first claw 30 (FIGS. 7 and 8) provided on the main body case 2 side, that is, an open end side, and a closed end. It is fixed to the end case 3 using a second claw 31 (FIG. 9) provided on the side.

  As can be understood from FIG. 7, one first claw 30 is provided on each side of the second front cover 4 b near the end of the main body case 2, and the two first claws 30 are 8, the lower end of the arm 32 extending downward is formed so as to protrude inward in the width direction of the end case.

  On the other hand, one second claw 31 is provided on each side of the longitudinal end of the second front cover 4b, and the two second claws 31 can be understood from FIG. It is formed toward the closed end.

  The second front cover 4 b uses the first double-sided adhesive tape 34 (FIG. 7) extending in the width direction on the open end side of the front flange 27 of the end case 3 and the first and second claws 30 and 31 described above. Although fixed to the end case 3, a second seal member 35 (FIG. 7) having a rectangular outer contour along the outer peripheral edge of the window 28 is interposed under the second front cover 4 b. Then, the window 28 is sealed.

  The first front cover 4a described above has substantially the same length as the main body case 2. On the other hand, the second front cover 4 b is shorter than the length dimension of the end case 3. For example, a metal belt-like member 38 is interposed at the abutting portion between the end surface of the first front cover 4a and the end surface of the second front cover 4b. FIG. 10 is inverted so as to clarify the shape of the belt-like member 38. The belt-shaped member 38 includes 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 front and rear ends of the belt-shaped member 38, that is, from both side edges on the main body case 2 side. The left and right legs 40 are formed with protruding pieces 42 formed by cutting and raising outward (outward in the width direction of the end case 3).

  As can be seen from FIG. 8, the leg 40 of the belt-like member 38 is inserted into a common hole with the arm 32 of the first claw 30 of the second front cover 4 b, and contacts the back surface of the arm 32 of the first claw 30. In the state of contact, the projecting piece 42 of the belt-like member 38 is engaged with the end case 4. Thereby, the belt-like member 38 can suppress the first front cover 4a from above the first front cover 4a, and can prevent the first claw 30 of the second front cover 4b from coming off by the legs 40 of the belt-like member 38. .

  Regarding the attachment of the first front cover 4a and the second front cover 4b, as shown in FIG. 7, a second double-sided adhesive tape extending across the end of the main body case 2 and the open end portion of the end case 3 45 and 45 are prepared, and this second double-sided adhesive tape 45 is adhered across the inner flange 13 of the main body case 2 and both side portions of the front flange 27 of the end case 3. Alternatively, both side portions of the first front cover 4a and the second front cover 4b may be bonded to each other. According to this, the first and second front covers 4a and 4b are joined in close contact with the main body case 2 and the end case 3 by the common second double-sided adhesive tape 45. The sealing performance of the boundary portion between the two front covers 4a and 4b and the belt-like member 38 can be enhanced.

  Reference numeral 46 in FIG. 7 indicates an additional third double-sided adhesive tape, and this third double-sided adhesive tape 46 is disposed at an appropriate interval in the longitudinal middle portion of the first front cover 4a. The main body case 2 is fixed by the third double-sided adhesive tape 46. That is, the third double-sided adhesive tape 46 is bonded across the inner flanges 13 and 13 of the main body case 2 at positions that do not interfere with the optical axis, and this third double-sided adhesive tape 46 is bonded. Regarding the portion, it is preferable that a partial protrusion (not shown) of the optical system unit 8 enters the slit 14 and has a structure flush with the inner flanges 13 and 13. As a result, the third double-sided adhesive tape 46 continuously extends across the first front cover 4a by adhering to both the inner flanges 13 and the protrusions of the optical system unit 8 filling between them. An adhesive surface can be formed.

  As described above, in the multi-optical axis photoelectric sensor 1 according to the embodiment, the light-transmitting front cover disposed on the front surface of the multi-optical axis photoelectric sensor 1 substantially constitutes the front surface of the main body case 2. The first front cover 4a is divided into a second front cover 4b that substantially constitutes the front surface of the end case 3, and a belt-like member 38 is interposed between the first and second front covers 4a and 4b. Therefore, the influence of the difference in thermal expansion between the case of the multi-optical axis photoelectric sensor 1 and the front cover can be reduced by the belt-shaped member 38.

  Also, the case of the multi-optical axis photoelectric sensor 1 adopts a split structure between the main body case 2 and the end cases 3 arranged at both ends thereof, and both the materials 2 and 3 are made of a material having relatively excellent heat dissipation. Therefore, although the optical element is housed not only in the main body case 2 but also in the end case 3, the internal heat can be radiated to the outside through the main body case 2 and the end case 3.

  Further, as a structure in which the portion adjacent to the belt-like member 38 of the second front cover 4b is attached to the end case 3, it is displaced in the longitudinal direction of the end case 3 by the first claw 30 protruding in the width direction of the end case 3. Similarly, even in the belt-like member 38, a configuration that can be displaced in the longitudinal direction of the end case 3 by the projecting piece 42 protruding in the width direction of the end case 3 is employed. These structures can absorb the difference in thermal expansion between the case of the multi-optical axis photoelectric sensor 1 and the front cover.

  Further, the window 28 through which the light of the optical element in the end case 3 passes can ensure the sealing performance related to the window 28 by the sealing material 35 extending around the entire outer periphery of the window 28.

  The sealing performance of the window 28 through which the optical axis passes will be described in detail. The entire circumference of the window 28 is surrounded by the front flange 27, whereby the second sealing material 35 continuous along the contour of the window 28 is formed. Can be used.

  FIG. 13 is a perspective view of a state in which the second front cover 4b is reversed and the back surface is turned up. FIG. 14 is a partial enlarged cross-sectional view in which a portion indicated by an arrow XIV in FIG. 8 is extracted.

  Referring to FIG. 13, in this embodiment, the second front cover 4b has a vertical rib 50 extending continuously on the back surface thereof. The vertical rib 50 has a position and a shape corresponding to the window 28 formed in the front flange 27 of the end case 3. Referring to FIG. 14, the window 28 formed on the front flange 27 of the end case 3 has a stepped shape on the inner peripheral surface 51 constituting the contour thereof.

  The second sealing material 35 is located between the stepped inner peripheral surface 51 and the vertical rib 50 and is designed to be compressed in the width direction of the end case 3 by both 51 and 50. Thereby, the 2nd sealing material 43 will be in the state closely_contact | adhered to the stepped inner peripheral surface 51 and the vertical rib 50, and, thereby, the sealing performance of the window 28 is ensured.

  The internal connector unit 50 (FIG. 6) facing the connector opening 22 of the end case 3 will be described. As can be seen from FIGS. 8 and 11, the internal connector unit 50 surrounds the connector main body 51 and the connector main body 51. And a connector holder 52 made of synthetic resin. The connector holder 52 has a pair of protrusions 53, 53 provided on both walls in the width direction of the end case 3, and the pair of protrusions 53, 53 extends in the longitudinal direction of the end case 3. .

  Corresponding to the pair of protrusions 53 of the connector holder 52, an engagement groove 55 having a cross-sectional shape complementary to the protrusion 53 is provided in the end case 3, and the engagement groove 55 is formed in the end case 3. It extends in the longitudinal direction. The internal connector unit 50 is inserted from the open end of the end case 3 with the protrusion 53 guided by the engagement groove 55.

  As shown in FIGS. 5, 11, and 12, the connector holder 52 of the internal connector unit 50 has a recess 56 at the end on the main body case 2 side. The recess 56 has a substantially rectangular shape of the end case 3.

  After the internal connector unit 50 is inserted into the end case 3, when the end case 3 is assembled to the main body case 2 containing the optical system unit 8 together with the substrate 12, the element holder 9 of the optical system unit 8 is attached to the element holder 9. The internal connector unit 50 is fixed at a predetermined position of the end case 3 by inserting and engaging the formed projection (not shown) into the recess 56 of the connector holder 52.

  That is, in the internal connector unit 50, the movement of the end case 3 in the width direction is restricted by the engagement between the pair of protrusions 53 of the connector holder 52 and the above-described engagement groove 55, while the length of the end case 3 is long. The movement in the direction is restricted by the engagement between the recess 56 of the connector holder 52 and the protrusion of the optical system unit 8 that is not shown. Accordingly, the internal connector unit 50 can be placed in a state where the connector main body 51 is positioned at a normal position facing the connector opening 22 of the end case 3.

  The internal connector unit 50 has a shape in which the connector pin 57 of the connector main body 51 is bent at a substantially right angle, and the inner end portion 57 a of the connector pin 57 is directed inward of the end case 3. The connector pin 57a is connected to the substrate 12 via a flexible cable (not shown).

  Thus, since the shape of the connector pin 57 is bent at a substantially right angle, the space between the back surface 3a (FIG. 3) of the end case 3 is smaller than when the connector pin 57 is installed in a straight state. The separation distance can be ensured, whereby the insulation distance can be ensured.

  Further, the end case 3 is provided with two screw holes 60 and 61 for screwing the external connector 6 to the end case 3 apart from each other in the longitudinal direction of the end case 3. As can be seen, the screw hole 61 on the open end side of the end case 3 is formed of a through hole.

  Both the screw holes 60 and 61 of the end case 3 are configured by bottomed holes like the one screw hole 60 in order to prevent contaminants from the outside from entering the end case 3. preferable.

  However, the open end side of the end case 3 lacks sufficient thickness to receive the internal connector unit 50. For this reason, when the open screw hole 61 is configured as a bottomed hole, the screw hole It is difficult to ensure a sufficient screw pitch of 61.

  Therefore, the screw hole 61 on the open end side of the end case 3 is configured as an open hole, and the ring-shaped seal member 54 is formed on the wall of the connector holder 52 of the internal connector unit 50 that practically forms the bottom of the screw hole 61. Is provided. As a result, it is possible to form a thread on the entire thickness of the end case 3, thereby ensuring the minimum thread necessary for screwing the external connector 6, while the ring-shaped seal member 54 The sealing performance of the opened screw hole 61 can be ensured.

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 a figure which shows the process of mounting | wearing with the lens unit of attachment in the middle of the assembly of the multi-optical axis photoelectric sensor of an Example, and the front cover is not illustrated. It is a perspective view of the edge part case of the multi-optical axis photoelectric sensor of an Example. It is the perspective view which looked at the edge part case from the opening end side. It is a front view of the end case with the front cover attached. It is a disassembled perspective view which shows the main body case and end part case which comprise the case of the multi-optical axis photoelectric sensor of an Example, and the 1st, 2nd front cover accompanying this. It is sectional drawing of the edge part case along the VIII-VIII line of FIG. It is sectional drawing of the edge part case along the IX-IX line of FIG. It is a perspective view which reverses and shows the metal strip | belt-shaped member interposed between the 1st, 2nd front cover. It is a perspective view which shows the process in which a connector unit is mounted | worn with an end part case. It is sectional drawing along the XII-XII line of FIG. It is a perspective view in the state where the back of the 2nd front cover was turned up. It is the elements on larger scale which extracted the part shown by the arrow XIV of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multi-optical axis photoelectric sensor 2 Main body case 3 End case 4a 1st front cover 4b 2nd front cover 5 Connector opening 6 External connector 8 Optical system unit 9 Element holder 16 Lens unit 27 Front flange of end case 28 End Window provided on the front flange of the case 30 First claw provided on the second front cover 35 Sealing material disposed around the window of the front flange of the end case 38 Band member 40 Band member leg 42 Band member 50 A vertical rib on the back surface of the second front cover 51 An inner peripheral surface of the end case window

Claims (10)

In a multi-optical axis photoelectric sensor comprising a plurality of optical elements arranged in a row spaced apart from each other in a case,
An optical system unit extending from one end of the multi-optical axis photoelectric sensor to the other end;
An element holder that constitutes a part of the optical system unit and holds the plurality of optical elements apart from each other;
A main body case that constitutes a central portion of the case of the multi-optical axis photoelectric sensor and that is open at both ends;
An end case coupled to the end of the body case, one end open and the other end closed;
A light transmissive first front cover provided on the front surface of the main body case;
A light transmissive second front cover provided on the front surface of the end case;
A multi-optical axis photoelectric sensor comprising a belt-like member interposed between the first and second front covers and attached to the end case. The multi-optical axis photoelectric sensor according to claim 1, wherein the belt-like member is attached to the end case so as to be displaceable in a longitudinal direction of the end case. 3. The multi-optical axis according to claim 1, wherein the second front cover is attached to the end case so as to be displaceable in a longitudinal direction of the end case at a portion adjacent to the band-shaped member. Photoelectric sensor. The end case is
A flange provided on the front surface of the end case;
A window formed on the flange and through which light to the optical element housed in the end case can pass;
The multi-optical axis photoelectric sensor according to any one of claims 1 to 3, wherein a sealing material extending over an outer peripheral edge of the window is provided between the flange and the second front cover. In a multi-optical axis photoelectric sensor comprising a plurality of optical elements arranged in a row apart from each other, and creating a multi-optical axis light curtain with the plurality of optical elements,
An optical system unit extending from one end to the other end of the multi-optical axis photoelectric sensor and holding the plurality of optical elements in a separated state;
A body case for opening both ends and surrounding a central portion of the optical system unit;
An end case for opening one end and closing the other end, and connecting an end on the open side to the end of the main body case to surround the end of the optical system unit;
A light-transmissive front cover disposed on the front surface of the end case;
The end case has a front flange provided with a window through which an optical axis located at an end of the optical system unit can pass,
The multi-optical axis photoelectric sensor, wherein the front cover is locked to the end case through the sealing material. The end case has a stepped peripheral wall that forms an outline of the window formed in the front flange;
The front cover has a rib extending continuously along a peripheral wall constituting the outline of the window in a portion corresponding to the window on the back surface thereof,
The multi-optical axis photoelectric sensor according to claim 5, wherein the sealing material is attached in a state of being in close contact with a rib of the front cover and a peripheral wall of the front flange. The front cover includes a first front cover provided on the front surface of the main body case and a second front cover provided on the front surface of the end case. The first and second front covers The multi-optical axis photoelectric sensor according to claim 5 or 6, wherein is a separate part. The multi-optical axis photoelectric sensor according to claim 7, further comprising a belt-like member interposed between the first and second front covers and attached to the end case. The multi-optical axis photoelectric sensor according to claim 8, wherein the belt-like member is attached to the end case so as to be displaceable in a longitudinal direction of the end case. The multi-optical axis according to claim 8 or 9, wherein the second front cover is attached to the end case so as to be displaceable in a longitudinal direction of the end case at a portion adjacent to the band-shaped member. Photoelectric sensor.

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