JP5881373B2 - Electronic component feeder - Google Patents

Description

  The present invention relates to an electronic component supply device, and more particularly to an electronic component supply device that supplies an electronic component by feeding a taped component containing the electronic component to a predetermined position.

  An electronic component supply device (hereinafter sometimes abbreviated as “supply device”) can feed a taped component in which an electronic component is accommodated in a large number of recesses formed in a carrier tape to the electronic component supply position. There is a so-called tape feeder having a taped part holding part for holding. The tape feeder is normally detachably attached to a slide portion that slidably supports the lower edge portion of the taped component holding portion, and can cope with replacement of the taped component. Examples of such a tape feeder include those described in the following patent documents.

JP 2010-109109 A

  A pair of side wall portions is formed on the slide portion that slidably supports the lower edge portion of the taped component holding portion so as to extend in the slide direction, and a direction intersecting the slide direction by the pair of side wall portions. Displacement of the taped component holder to the head is prohibited. Further, the slide part is formed with a retaining part at the upper part of the pair of side wall parts, and the upward removal of the taped component holding part from the slide part is prohibited. With the slide portion having such a structure, the taped component holding portion is supported in a state in which only movement in the slide direction is allowed.

  It is not desirable that the lower edge portion of the taped component holding portion supported in such a manner rattle at the inside of the slide portion, that is, the portion defined by the pair of side wall portions and the retaining portion. In order to suppress the rattling as much as possible, the internal dimensions of the slide part, such as the distance between the pair of side wall parts, are set to be slightly larger than the dimensions of the lower edge part of the taped component holding part. For this reason, when the lower edge of the taped component holding part is fitted into the slide part, the taped part holding part is in a state parallel to the slide part, and the lower edge part is maintained while maintaining the parallel state. It needs to be inserted into the slide part, which takes time. This invention is made | formed in view of such a situation, and makes it a subject to provide the supply apparatus which can fit the lower edge part of a taped component holding part to a slide part easily.

In order to solve the above-described problem, an electronic component supply apparatus according to claim 1 of the present application sends a taped component in which an electronic component is accommodated in a large number of recesses formed in a carrier tape to a supply position of the electronic component. A taped component holding part that holds the taped part, and a mounting part that has a slide part that slidably supports the lower edge of the taped part holding part, and the taped part holding part is detachably mounted. An electronic component supply apparatus comprising: the slide portion is formed so as to extend in a sliding direction of the taped component holding unit, and displacement of the taped component holding unit in a direction intersecting with the sliding direction is prohibited. An introduction portion having a pair of first side wall portions and positioned at an end portion on a side opposite to a sliding direction at the time of mounting, which is a sliding direction when mounting the taped component holding portion; of A pair of second side wall portions continuous so as to extend from the one side wall portion in the sliding direction when mounted, and a retaining portion for preventing the taped component holding portion from being pulled upward; A retaining state supporting portion that supports the portion while only allowing movement in the sliding direction, and at least one of the introduction portion and the lower edge portion of the taped component holding portion is magnetized , The magnetic force generated by at least one of the introduction portion and the lower edge portion of the taped component holding portion is larger in the introduction portion as it is closer to the end portion of the introduction portion on the slide direction side when mounted, and the taped component In the lower edge part of a holding | maintenance part, it is comprised so that it may become so large that it is close to the edge part which follows the said securing state support part of the said introduction part .

  The electronic component supply device according to claim 2 is the electronic component supply device according to claim 1, wherein the magnetic force generated by at least one of the introduction portion and the lower edge portion of the taped component holding portion is When the taped component holding portion is supported only by the introduction portion, the taped component holding portion is configured to have a size that can prevent the taped component holding portion from falling off the slide portion.

The electronic component supply device according to claim 3 is the electronic component supply device according to claim 1 or 2 , wherein the retaining state support portion includes the pair of side wall portions and the retaining portion. It is configured to be a T-groove.

In the supply apparatus according to claim 1, the slide portion is formed with a pair of side wall portions and a retaining portion, and a retaining state support portion is formed, and the retaining portion is not formed, and only a pair of side wall portions are formed. It is comprised by the introduction part. In other words, when inserting the lower edge of the taped part holding part into the slide part, first, the lower edge of the taped part holding part is fitted into the introduction part, and then the lower edge of the taped part holding part Is slid toward the retaining support. Thereby, it becomes possible to easily insert the lower edge portion of the taped component holding portion into the retaining state support portion. Furthermore, in the supply device according to the first aspect, at least one of the introduction portion and the lower edge portion of the taped component holding portion is magnetized. For this reason, the magnetic force makes it easy to fit the lower edge portion of the taped component holding portion into the introduction portion, and it is easy to maintain the taped component holding portion in a state parallel to the slide portion. Therefore, according to the supply device of the first aspect, the lower edge portion of the taped component holding portion can be easily fitted to the slide portion. Also, the lower edge of the taped component holding part is usually longer than the introduction part, and when the lower edge is supported only by the introduction part, the rear end part of the lower edge part is the rear end part of the introduction part. It will be in the state extended from. For this reason, the taped component holding part may have a moment centered on the rear end of the introduction part, and the moment is in the front end of the taped part holding part, that is, in the feeding direction of the taped part. The closer to the end of the side, the larger it becomes. In view of this, in the supply device according to claim 1, the magnetic force generated between the lower edge portion of the taped component holding portion and the introduction portion is the front end portion of the introduction portion, that is, the retaining state in the introduction portion. The closer to the end portion that is continuous with the support portion, the larger, and the lower edge portion of the taped component holding portion is made larger as it is closer to the front end portion of the taped component holding portion. Thereby, it becomes possible to maintain effectively the close_contact | adherence state by the magnetic force of the lower edge part and introduction part of a tape-ized component holding part.

  Further, in the supply device according to claim 2, the lower edge portion of the taped component holding portion is supported only by the introducing portion by the magnetic force generated between the lower edge portion of the taped component holding portion and the introducing portion. Even at times, the taped component holding portion is prevented from falling off the slide portion. That is, when the lower edge portion of the taped component holding portion is brought into close contact with the introduction portion by magnetic force, the operator removes the hand from the taped component holding portion before the lower edge portion is inserted into the retaining state support portion. Even if they are released, the close contact state between the lower edge portion and the introduction portion due to the magnetic force is maintained. Therefore, according to the supply device of the second aspect, it is possible to reduce the labor of the operator when inserting the lower edge portion of the taped component holding portion into the slide portion.

Moreover, in the supply apparatus of Claim 3 , the removal-prevention state support part is a T groove. Thereby, the structure of the slide part can be simplified.

It is a perspective view which shows the electronic component mounting apparatus comprised by arranging two electronic component mounting machines with which the electronic component supply apparatus which is an Example of this invention was attached. It is a top view which shows a part of tape feeder of the electronic component supply apparatus with which the electronic component mounting machine shown in FIG. 1 is equipped, and the tape-ized component sent out by the tape feeder. It is a perspective view which shows the electronic component supply apparatus with which the electronic component mounting machine shown in FIG. 1 is provided. It is sectional drawing which shows the tape-ized component holding part of the electronic component supply apparatus shown in FIG. It is a perspective view which shows the lower edge part of the tape-ized component holding part shown in FIG. It is a perspective view which shows the slide part of the electronic component supply apparatus shown in FIG. It is sectional drawing in the AA line shown in FIG. It is sectional drawing in the BB line shown in FIG. It is a perspective view which shows the slide part with which the electronic component supply apparatus of a modification is provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as modes for carrying out the present invention.

  FIG. 1 shows an electronic component mounting apparatus (hereinafter sometimes abbreviated as “mounting apparatus”) 10. The figure is a perspective view in which a part of the exterior component of the mounting apparatus 10 has been removed. The mounting apparatus 10 includes one system base 12 and two electronic component mounting machines (hereinafter, may be abbreviated as “mounting machines”) 16 arranged side by side adjacent to each other on the system base 12. In other words, the electronic component is mounted on the circuit board. In the following description, the direction in which the mounting machines 16 are arranged is referred to as an X-axis direction, and a horizontal direction perpendicular to the direction is referred to as a Y-axis direction.

  Each of the mounting machines 16 included in the mounting apparatus 10 mainly includes a mounting machine main body 24 configured to include a frame unit 20 and a beam unit 22 overlaid on the frame unit 20, and a circuit board in the X-axis direction. A transport device 26 that transports and fixes the set position at a set position, a mounting head 28 that mounts an electronic component on a circuit board fixed by the transport device 26, and an X-axis mounted head 28 disposed on the beam unit 22. A moving device 30 that moves in the direction and the Y-axis direction, and an electronic component supply device 32 that is disposed in front of the frame portion 20 and supplies electronic components to the mounting head 28 (hereinafter, may be abbreviated as “supply device”) 32 It has.

  The transport device 26 includes two conveyor devices 40 and 42, and the two conveyor devices 40 and 42 are parallel to each other and extend in the X-axis direction so that the central portion in the Y-axis direction of the frame portion 20. It is arranged. Each of the two conveyor devices 40 and 42 conveys the circuit board supported by each conveyor device 40 and 42 in the X-axis direction by an electromagnetic motor (not shown) and holds the circuit board fixedly at a predetermined position. It is supposed to be a structure.

  The mounting head 28 mounts an electronic component on a circuit board held by the transport device 26, and has a suction nozzle 50 that sucks the circuit component on the lower surface. The suction nozzle 50 communicates with negative pressure air and a positive pressure air passage via a positive / negative pressure supply device (not shown), and sucks and holds the electronic component with a negative pressure, so that a slight positive pressure is supplied. It is structured to release the held electronic component.

  The moving device 30 is an XY robot type moving device, an X-axis slider 52 that holds the mounting head 28, a Y-axis slider (not shown) that holds the X-axis slider 52 so as to be slidable in the X-axis direction, An electromagnetic motor (not shown) that slides the X-axis slider 52 in the X-axis direction and an electromagnetic motor (not shown) that slides the Y-axis slider in the Y-axis direction are provided. By the operation of these two electromagnetic motors, The mounting head 28 held by the X-axis slider 52 can be moved to an arbitrary position.

  The supply device 32 is disposed at the front end of the frame portion 20 and is a feeder-type supply device. The supply device 32 has a plurality of tape feeders 64 that accommodate tape-shaped components (see FIG. 2) 60 on which electronic components are taped and wound around a reel 62. The parts are sequentially supplied to the supply position to the mounting head 28.

  As shown in FIG. 2, the taped component 60 includes a carrier tape 74 in which a large number of receiving recesses 70 and feed holes 72 are formed at an equal pitch, an electronic component 76 received in the receiving recess 70, and a carrier tape 74. It is comprised from the top cover tape 78 which covers the accommodation recessed part 70 in which the electronic component 76 was accommodated. Further, as shown in FIG. 3, the tape feeder 64 has a reel holding portion 80 for holding a reel 62 around which the taped component 60 is wound, and a taped component 60 drawn from the reel 62 extending to the upper end surface. And a feeder main body 82 to be present.

  As shown in FIG. 4, a sprocket 84 that engages with a feed hole 72 formed in the carrier tape 74 of the taped component 60 is built in the feeder main body 82, and the sprocket 84 is rotated. The taped component 60 with the top cover tape 78 attached to the carrier tape 74 is sent out in the direction away from the reel 62 on the upper end surface of the feeder main body 82. Then, when the top cover tape 78 is peeled off from the carrier tape 74 by a peeling device (not shown), the accommodation recesses 70 in which the electronic components 76 are accommodated are sequentially released at the tip of the upper end surface of the feeder main body 82. The electronic component 76 is taken out by the suction nozzle 50 from the released accommodation recess 70.

  The tape feeder 64 can be attached to and detached from a tape feeder mounting base (hereinafter sometimes abbreviated as “mounting base”) 90 fixedly provided at the front end of the frame portion 20. As shown in FIG. 3, the mounting base 90 includes a slide portion 92 formed so as to extend in the Y-axis direction, and a standing surface portion 96 erected on the side of the slide portion 92 close to the transport device 26. Has been. The slide portion 92 can be slid in a state in which the lower edge portion of the feeder main body 82 of the tape feeder 64 is fitted, and the standing surface portion in a state in which the lower edge portion of the feeder main body 82 is fitted. The side wall surface of the feeder main body 82 on the side in the feeding direction of the taped component 60 is attached to the standing surface portion 96 by sliding in the direction approaching 96.

  More specifically, the slide portion 92 has a direction in which the tape feeder 64 approaches the upright surface portion 96, that is, on the side opposite to the sliding direction at the time of mounting, which is the sliding direction when the tape feeder 64 is mounted on the mounting base 90. A plurality of introduction grooves 98 that are positioned and a plurality of T grooves 100 that extend from the plurality of introduction grooves 98 in the sliding direction when mounted are formed. That is, a plurality of slide grooves 102 constituted by the introduction grooves 98 and the T grooves 100 are formed in the slide portion 92 so as to extend in the Y-axis direction. On the other hand, as shown in FIG. 5, a guide portion 104 fitted into the slide groove 102 is provided at the lower edge portion of the feeder main body 82. The guide portion 104 has an inverted T-shaped cross section, and is divided into a wide portion 106 constituting the bottom portion and a narrow portion 108 extending upward from the wide portion 106. In addition, the guide part 104 is shape | molded by the material which has magnetism, specifically, steel materials etc.

  In order to explain the slide groove 102 in detail, FIG. 6 shows an introduction groove 98 of one slide groove 102 and a part of the T groove 100 continuous to the introduction groove 98. As shown in FIG. 7 which is a cross-sectional view taken along the line AA in FIG. 6, the T groove 100 of the slide groove 102 includes a bottom surface portion 110 and a pair of side wall portions extending upward from both edges of the bottom surface portion 110. 112 and a pair of projecting portions 114 projecting inward from the upper ends of the pair of side wall portions 112. Each of the pair of side wall portions 112 is formed so as to extend in the Y-axis direction, and the distance between the pair of side wall portions 112 is slightly larger than the width of the wide portion 106 of the guide portion 104. Yes. Further, the distance between the pair of protruding portions 114 is slightly larger than the width of the narrow portion 108 of the guide portion 104. Further, the height of the pair of side wall portions 112 is slightly higher than the height of the wide portion 106, and the height of the pair of protruding portions 114 is lower than the height of the narrow portion 108. As a result, the guide portion 104 can be fitted into the T-groove 100, and the pair of side wall portions 112 is prohibited from shifting in the horizontal direction intersecting the Y-axis direction, and the pair of protruding portions 114. , Upward slipping is prohibited. That is, the guide portion 104 is supported by the T groove 100 so as to be slidable only in the Y-axis direction.

  Further, as shown in FIG. 8 which is a cross-sectional view taken along line BB in FIG. 6, the introduction groove 98 of the slide groove 102 is a pair of bottom surfaces 120 and a pair extending upward from both edges of the bottom surface portions 120. It is partitioned by the side wall portion 122. Each of the pair of side wall parts 122 is formed so as to extend in the Y-axis direction, and the distance between the pair of side wall parts 122 is slightly larger than the width of the wide part 106 of the guide part 104. Yes. As a result, the guide portion 104 can be fitted into the introduction groove 98, and the pair of side wall portions 122 is prohibited from shifting in the horizontal direction intersecting with the Y-axis direction, but is prevented from being pulled upward. Not. That is, the guide portion 104 can be fitted into the introduction groove 98 from above. Further, the side wall portion 122 of the introduction groove 98 is continuous with the side wall portion 112 of the T groove 100, and the side wall portion 122 of the introduction groove 98 and the side wall portion 112 of the T groove 100 are positioned on one straight line. . Accordingly, the guide portion 104 can be fitted into the T-groove 100 by sliding the guide portion 104 fitted in the introduction groove 98 toward the T-groove 100.

  Further, five bottomed holes 124 are formed side by side in the sliding direction on the bottom surface portion 120 of the introduction groove 98, and the interval between adjacent bottomed holes 124 is the same. A magnet 126 having substantially the same shape as the bottomed hole 124 is press-fitted into each of the five bottomed holes 124. As a result, the introduction groove 98 is magnetized, and the bottom surface of the guide portion 104 fitted in the introduction groove 98, that is, the bottom surface of the wide portion 106 is formed by the bottom surface portion 120 by the magnetic force of the magnetized introduction groove 98. It comes to adhere to. Note that the upper surface of the bottom surface portion 120 and the upper surface of the magnet 126 are flush with each other, and smooth sliding in the introduction groove 98 of the guide portion 104 is ensured.

  With the structure described above, when the tape feeder 64 is mounted on the mounting base 90, first, the guide portion 104 is fitted into the introduction groove 98. Since the guide portion 104 can be fitted into the introduction groove 98 from the opening above the introduction groove 98, it can be easily performed. Further, since the introduction groove 98 is magnetized as described above, it is easier to fit the guide portion 104 to the introduction groove 98 by the magnetic force thereof. Further, the bottom surface of the wide portion 106 is brought into close contact with the bottom surface portion 120 of the introduction groove 98 by the magnetic force, and the guide portion 104 is maintained in a state parallel to the introduction groove 98, that is, the slide groove 102. By sliding the guide portion 104 parallel to the slide groove 102 toward the T groove 100, the guide portion 104 can be smoothly fitted into the T groove 100. Then, by further sliding the guide portion 104 fitted in the T-groove 100, the side wall surface on the distal end side of the feeder main body 82 is attached to the standing surface portion 96, and the tape feeder 64 is attached to the attachment table 90. . As described above, in the supply device 32, the tape feeder 64 can be easily mounted on the mounting base 90, and for example, the replacement time of the tape feeder 64 can be shortened.

  Moreover, in this supply apparatus 32, as shown in FIG. 3, the length of the introduction groove 98 is about 1/3 of the length of the slide groove 102, and is relatively long. Thereby, the guide part 104 can be easily fitted into the introduction groove 98. Furthermore, it is easy to maintain the guide portion 104 in a state parallel to the slide groove 102.

  Further, in the supply device 32, the tape feeder 64 is slidable even when the guide portion 104 is fitted only in the introduction groove 98 due to the magnetic force generated between the guide portion 104 and the introduction groove 98. It is made not to fall off. That is, the magnetic force of the magnet 126 attached to the introduction groove 98 is such that the tape feeder 64 can be prevented from falling off from the slide portion 92 when the guide portion 104 is fitted only in the introduction groove 98. ing. As a result, when the guide portion 104 is brought into close contact with the introduction groove 98 by magnetic force, the guide portion 104 and the magnetic guide portion 104 can be connected to each other even if the operator removes the hand from the tape feeder 64 before the guide portion 104 is fitted into the T groove 100. The close contact state with the introduction groove 98 is maintained. Thereby, it is possible to reduce the labor of the operator when the tape feeder 64 is mounted.

  Incidentally, in the above-described embodiment, the electronic component supply device 32 is an example of an electronic component supply device. The feeder main body 82 and the tape feeder mounting base 90 constituting the electronic component supply device 32 are a taped component holding unit and a mounting unit. It is an example. The slide portion 92 of the tape feeder mounting base 90 is an example of a slide portion, and the introduction groove 98 and the T groove 100 formed in the slide portion 92 are examples of an introduction portion and a retaining state support portion. The side wall part 122 that defines the introduction groove 98 is an example of a first side wall part, and the side wall part 112 and the protruding part 114 that define the T groove 100 are examples of a second side wall part and a retaining part.

  In addition, this invention is not limited to the said Example, It is possible to implement in the various aspect which gave various change and improvement based on the knowledge of those skilled in the art. Specifically, for example, in the above embodiment, the five magnets 126 are arranged in the introduction groove 98 at an equal pitch, but may be arranged at different pitches. Specifically, for example, as shown in FIG. 9, the five magnets 126 are arranged so that the interval between the adjacent magnets 126 becomes narrower as the end of the introduction groove 98 on the side continuous with the T groove 100 becomes closer. It can be arranged in the introduction groove 98. By arranging in this way, the magnetic force generated between the guide portion 104 and the introduction groove 98 can be increased as it is closer to the end portion of the introduction groove 98 that is continuous with the T groove 100. Accordingly, it is possible to effectively prevent the tape feeder 64 from dropping from the slide groove 102 when the guide portion 104 is fitted only in the introduction groove 98.

  Specifically, since the guide portion 104 is longer than the introduction groove 98, when the guide portion 104 is fitted only in the introduction groove 98, the rear end portion of the guide portion 104 extends from the rear end portion of the introduction groove 98. It will be in the extended state. Therefore, a moment is generated in the tape feeder 64 around the rear end portion of the introduction groove 98, and the moment is close to the front end portion of the tape feeder 64, that is, the end portion of the tape feeder 64 in the feeding direction side. It gets bigger. For this reason, the magnetic force generated between the guide portion 104 and the introduction groove 98 is increased as it is closer to the end portion of the introduction groove 98 that is continuous with the T-groove 100, so It is possible to effectively maintain the state, and it is possible to effectively prevent the tape feeder 64 from falling off the slide groove 102.

  In order to increase the magnetic force generated between the guide portion 104 and the introduction groove 98 closer to the end portion of the introduction groove 98 that is continuous with the T groove 100, not only the arrangement pitch of the magnets is changed, You may arrange | position the magnet from which magnetic force differs. That is, a magnet having a stronger magnetic force may be disposed closer to the end of the introduction groove 98 that is continuous with the T groove 100. In the above embodiment, the introduction groove 98 is magnetized by disposing a magnet in the introduction groove 98. However, the introduction groove 98 is magnetized by forming the introduction groove 98 from a ferromagnetic material. Also good. That is, the introduction groove 98 itself may be spontaneously magnetized.

  In the above embodiment, the introduction groove 98 is magnetized, but the guide portion 104 may be magnetized instead of the introduction groove 98, and both the introduction groove 98 and the guide portion 104 may be magnetized. Furthermore, the guide part 104 may be magnetized so that the magnetic force generated between the guide part 104 and the introduction groove 98 increases as the tip part of the guide part 104 is closer. Further, the guide part 104 may be magnetized by a magnet, or the guide part 104 itself may be spontaneously magnetized.

  Moreover, in the said Example, the feeder main body 82 is employ | adopted as a taped component holding | maintenance part, and the taped component holding | maintenance part contains the sending device for sending out taped components. However, the taped component holding unit may be any unit that holds the taped component so that the taped component can be sent out to the supply position, and does not need to include a delivery device. In other words, a holding device that holds the tape feeder in a state where the taped component is wound, a taped component path that guides the taped component pulled out from the holder to the electronic component supply position, and a taped component path. The taped component path, or the taped component path integrated with the holder when the taped component that has been pulled out is divided into the delivery device that sends it to the supply position, is used as the taped component holder. It is possible to adopt. By the way, when the taped parts path or the taped parts path and the holder integrated is adopted as the taped parts holding part, the slide part, that is, the mounting on the housing containing the delivery device Parts are provided.

  32: Electronic component supply device 82: Feeder main body (taped component holding portion) 90: Tape feeder mounting base (mounting portion) 92: Slide portion 98: Introducing groove (introducing portion) 100: T groove (preventing state supporting portion) 112 : Side wall part (second side wall part) 114: Projection part (prevention part) 122: Side wall part (first side wall part)

Claims (3)

A taped component holding unit that holds a taped component in which an electronic component is accommodated in a large number of receiving recesses formed on the carrier tape so as to be able to be sent out to a supply position of the electronic component;
An electronic component supply device comprising: a slide portion that slidably supports a lower edge portion of the taped component holding portion; and a mounting portion on which the taped component holding portion is detachably mounted,
The slide part is
The taped component holding part is formed to extend in the sliding direction of the taped component holding part, and has a pair of first side wall parts that prohibits the displacement of the taped component holding part in a direction intersecting the sliding direction. An introduction portion located at an end portion on the side opposite to the sliding direction at the time of mounting, which is a sliding direction when the holding portion is mounted;
A pair of second side wall portions that are continuous from the pair of first side wall portions so as to extend in the sliding direction at the time of mounting, and a retaining portion that prohibits the taped component holding portion from being pulled upward. The taped component holding part is configured with a removal state support part that supports the taped part holding part in a state in which only movement in the sliding direction is allowed,
At least one of the introduction part and the lower edge part of the taped part holding part is magnetized, and the magnetic force generated by at least one of the introduction part and the lower edge part of the taped part holding part is:
In the introduction part, the closer to the end of the introduction part on the side in the sliding direction, the larger the introduction part,
An electronic component supply device that is larger at the lower edge portion of the taped component holding portion as it is closer to an end portion that is continuous with the retaining state support portion of the introduction portion . Magnetic force generated by at least one of the introduction portion and the lower edge portion of the taped component holding portion is:
The electronic component supply apparatus according to claim 1, wherein the taped component holding unit is configured to be a size capable of preventing the taped component holding unit from falling off from the slide portion when the taped component holding unit is supported only by the introduction unit. . The retaining state support portion is
The electronic component supply device according to claim 1 , wherein the electronic component supply device is a T groove formed of the pair of side wall portions and the retaining portion.

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