Laser cutting equipment for aluminum alloy profile machining

Abstract

The invention relates to the technical field of laser cutting, in particular to laser cutting equipment for aluminum alloy profile machining, which comprises a protective plate and a guide base, the guide base is fixedly connected to the inner wall of the protective plate, and the top of the guide base is slidably connected with a rotating frame. A rack, a rotating frame and an aluminum alloy profile can be driven to rotate under rotation of a threaded protruding strip, a telescopic column can stretch out and draw back in the rotating direction of the rotating frame, and meanwhile under limitation of a first limiting column, it is guaranteed that the rotating angle of the aluminum alloy profile is the same as the rotating angle of the rotating frame in the stress rotating process of the aluminum alloy profile; and the aluminum alloy sections are cut under the sliding of the sliding frame, and cutting of the sections with different radians can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of laser cutting, and in particular to a laser cutting device for processing aluminum alloy profiles. Background Art

[0002] Aluminum alloy profiles refer to aluminum alloy extruded profiles that are in the required shape. Aluminum alloys are widely used in aerospace, automobile manufacturing, architectural decoration and other fields due to their light weight, high strength, corrosion resistance and other excellent properties.

[0003] The Chinese announcement number is: CN119260217A, which discloses a CNC laser cutting device for processing aluminum alloy profiles, including a processing table, on which a plurality of groups of pillars are fixedly connected, and the top ends of the plurality of groups of pillars are fixedly connected to top plates; the output end of the telescopic cylinder is fixedly connected to a processing assembly; the processing assembly includes a top block, and a first motor is installed at the bottom end of the top block, and the output end of the first motor is transmission-connected to a cutting mechanism; the first motor drives the first electric slide to rotate to a preset angle, and the first electric slide drives the laser cutting knife to move horizontally, so as to perform linear cutting of the preset angle on the aluminum alloy profile; the first electric slide drives the laser cutting knife to move horizontally to a preset position, and the first motor drives the first electric slide to rotate, so as to perform annular cutting of the aluminum alloy profile with a preset inner diameter;

[0004] Although the above patent uses the first electric slide to drive the laser cutting knife to move horizontally to perform linear cutting of a preset angle and circular cutting of a preset inner diameter on the profile, considering that aluminum alloy is used in many scenarios and the shapes of the profiles are diverse, when it is necessary to cut aluminum alloy profiles with curved angles, the shape cut by plane cutting is expected to be larger than the shape of curved cutting, that is, it is necessary to adapt to the shape of the curved aluminum alloy profile for cutting;

[0005] In view of this, we propose a laser cutting device for processing aluminum alloy profiles. Summary of the invention

[0006] The purpose of the present invention is to provide a laser cutting device for processing aluminum alloy profiles to solve the problems raised in the above background technology.

[0007] To achieve the above-mentioned object, the present invention provides a laser cutting device for aluminum alloy profile processing, comprising a guard plate and a guide base, wherein electric slide rails are fixedly connected to both sides of the guard plate, a sliding frame is slidably connected to the outer side of the electric slide rail, a sliding block is slidably connected to the outer wall of the top of the sliding frame, and a cutting head is telescopically connected to the bottom of the sliding block;

[0008] The guide base is fixedly connected to the inner wall of the guard plate, the top of the guide base is slidably connected to a rotating frame, the top of the rotating frame is fixedly connected to a grid plate, and the bottom of the outer wall of the rotating frame is fixedly connected to a rack;

[0009] The top of the guide base is fixedly connected to a motor, the top of the guide base is rotatably connected to a rotating rod, the outer walls on both sides of the guide base are fixedly connected to side plates, the top of the side plates is slidably connected to a limiting slider, and a limiting component is arranged on the inner side of the limiting slider.

[0010] As a preferred embodiment of the present invention, both sides of the upper bottom of the sliding frame are fixedly connected to a No. 1 limiting column, the outer wall of the limiting sliding block is fixedly connected to a telescopic column, and the telescopic column and the No. 1 limiting column are in the same vertical plane.

[0011] As a preferred embodiment of the present invention, the output end of the motor is fixedly connected to a transmission roller, the outer wall of the transmission roller is sleeved with a transmission belt, and the other end of the transmission belt is sleeved on the outer wall of the rotating rod.

[0012] As a preferred embodiment of the present invention, a threaded protrusion strip is fixedly connected to the outer wall of the rotating rod, and the threaded protrusion strip is meshingly connected to the rack.

[0013] As a preferred embodiment of the present invention, the top of the side panel is fixedly connected to a cross bar, the top of the side panel is provided with an irregular groove, the top of the irregular groove is provided with a touch sensor, a groove is provided at the bottom position of the middle end of the cross bar, and the limiting slider is slidably connected between the top of the side panel and the bottom position of the cross bar.

[0014] As a preferred embodiment of the present invention, the limiting slider is in an internal hollow state, and the limiting component includes a No. 1 sliding member, the No. 1 sliding member is in the shape of the letter U, and the No. 1 sliding member is slidably connected to the inner side of the limiting slider, and the top of the end of the No. 1 sliding member is fixedly connected with a sliding column, and the sliding column is slidably connected to the inner side of the limiting slider, and a No. 1 square groove is provided on the inner sides of both sides of the No. 1 sliding member, and a No. 1 spring is arranged on the top of the No. 1 sliding member, and the outer walls on both sides of the No. 1 sliding member are fixedly connected with extension plates, and a No. 2 spring is arranged on the top of the extension plate, and the two ends of the No. 2 spring respectively abut against the top inner wall of the limiting slider and the top of the extension plate.

[0015] As a preferred embodiment of the present invention, the inner side of the limiting slider is slidably connected with a No. 2 sliding member, the No. 1 spring is arranged between the No. 1 sliding member and the No. 2 sliding member, and the outer walls on both sides of the No. 2 sliding member are provided with No. 2 square grooves, and the height of the No. 2 square groove is the same as that of the No. 1 square groove.

[0016] As a preferred embodiment of the present invention, a buckle strip is fixedly connected to the top of the second sliding member, and the width of the buckle strip matches the width of the groove.

[0017] As a preferred embodiment of the present invention, the shape of the irregular groove matches the bottom shape of the No. 1 sliding member.

[0018] As a preferred embodiment of the present invention, a connecting rod is arranged between the No. 1 sliding member and the No. 2 sliding member, the middle end of the connecting rod is rotatably connected to the inner wall of the limiting sliding block, and both ends of the connecting rod are fixedly connected with No. 2 limiting columns, the diameter of the No. 2 limiting column is the same as the height of the No. 1 square groove and the No. 2 square groove, and the No. 2 limiting columns at both ends are respectively located on the inner sides of the No. 1 square groove and the No. 2 square groove.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. In the laser cutting equipment for processing aluminum alloy profiles, the driving motor drives the rotating rod and the threaded raised strip to rotate together with the transmission belt, and the rotation of the threaded raised strip will also drive the rack, the rotating frame and the grid plate to rotate together. The aluminum alloy profile will also rotate a certain angle under the rotation of the grid plate. The telescopic column will extend and retract with the rotation direction of the rotating frame. At the same time, under the restriction of the No. 1 limiting column, the rotation angle of the aluminum alloy profile is guaranteed to be the same as the rotation angle of the rotating frame during the force rotation process, and the aluminum alloy profile can be cut under the sliding of the sliding frame, which can realize the cutting of profiles with different curvatures.

[0021] 2. In the laser cutting equipment for processing aluminum alloy profiles, when the limiting slider slides to the middle position, the No. 1 sliding member is moved downward by using the No. 1 spring, and then the telescopic column is fixed by using the connecting rod, so that the aluminum alloy profile is fixed by using the end of the telescopic column and the No. 1 limiting column, and then the arc profile can move with the cooperation with the threaded protrusion to cut the arc surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an overall three-dimensional schematic diagram of the aluminum alloy profile processing laser cutting equipment of the present invention;

[0023] Figure 2 It is a schematic diagram of the overall longitudinal section of the aluminum alloy profile processing laser cutting equipment of the present invention;

[0024] Figure 3 It is a schematic diagram of the overall transverse section of the aluminum alloy profile processing laser cutting equipment of the present invention;

[0025] Figure 4 It is a schematic diagram of the overall inner side of the laser cutting equipment for aluminum alloy profile processing of the present invention;

[0026] Figure 5 It is a three-dimensional schematic diagram of the overall inner side of the aluminum alloy profile processing laser cutting equipment of the present invention;

[0027] Figure 6This is a three-dimensional schematic diagram of the inner side of the guide base of the aluminum alloy profile processing laser cutting equipment of the present invention;

[0028] Figure 7 A three-dimensional schematic diagram of a limiting slider of the aluminum alloy profile processing laser cutting equipment of the present invention;

[0029] Figure 8 It is a three-dimensional schematic diagram of the limiting components of the aluminum alloy profile processing laser cutting equipment of the present invention;

[0030] The meaning of each number in the figure is:

[0031] 1. Guard plate; 11. Electric slide rail; 111. Sliding frame; 112. Sliding block; 113. Cutting head; 114. Limiting column No. 1; 2. Guide base; 21. Motor; 211. Drive roller; 22. Drive belt; 23. Rotating rod; 231. Threaded raised strip; 24. Side plate; 241. Cross bar; 2411. Groove; 242. Irregular groove; 25. Limiting slider; 26. Telescopic column; 27. Limiting assembly; 271. Sliding piece No. 1; 2711. Square groove No. 1; 2712. Extension plate; 2713. Sliding column; 2714. Spring No. 1; 272. Spring No. 2; 273. Sliding piece No. 2; 2731. Square groove No. 2; 274. Connecting rod; 2741. Limiting column No. 2; 275. Buckle strip; 3. Rotating frame; 31. Grid plate; 32. Rack. DETAILED DESCRIPTION

[0032] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] Embodiment 1

[0035] See also Figure 1-Figure 8As shown, this embodiment provides a laser cutting device for processing aluminum alloy profiles, including a guard plate 1 and a guide base 2, electric slide rails 11 are fixedly connected to both sides of the guard plate 1, a sliding frame 111 is slidably connected to the outer side of the electric slide rail 11, a sliding block 112 is slidably connected to the top outer wall of the sliding frame 111, and a cutting head 113 is telescopically connected to the bottom of the sliding block 112, the guide base 2 is fixedly connected to the inner wall of the guard plate 1, the top of the guide base 2 is slidably connected to a rotating frame 3, the top of the rotating frame 3 is fixedly connected to a grid plate 31, the bottom of the outer wall of the rotating frame 3 is fixedly connected to a rack 32, the top of the guide base 2 is fixedly connected to a motor 21, the top of the guide base 2 is rotatably connected to a rotating rod 23, the outer walls of both sides of the guide base 2 are fixedly connected to side plates 24, the top of the side plates 24 is slidably connected to a limiting slider 25, and a limiting component 27 is arranged on the inner side of the limiting slider 25.

[0036] like Figure 2-Figure 5 As shown, the two sides of the upper bottom of the sliding frame 111 are fixedly connected to the No. 1 limiting column 114, the outer wall of the limiting slider 25 is fixedly connected to the telescopic column 26, the telescopic column 26 and the No. 1 limiting column 114 are on the same vertical plane, the output end of the motor 21 is fixedly connected to the transmission roller 211, the outer wall of the transmission roller 211 is sleeved with a transmission belt 22, the other end of the transmission belt 22 is sleeved on the outer wall of the rotating rod 23, the outer wall of the rotating rod 23 is fixedly connected to the threaded protrusion strip 231, and the threaded protrusion strip 231 is meshed and connected with the rack 32;

[0037] Among them, Figure 4 As shown, the upper end of the telescopic column 26 is bent at an angle of 90 degrees. When the aluminum alloy profile is conveyed to the position of the telescopic column 26, the side of the bent portion of the telescopic column 26 in the extended state will block the input end of the arc profile to a certain extent. The telescopic column 26 here is electrically telescopic.

[0038] like Figure 2-Figure 7As shown, a cross bar 241 is fixedly connected to the top of the side plate 24, an irregular groove 242 is provided on the top of the side plate 24, a touch sensor is provided on the top of the irregular groove 242, a groove 2411 is provided at the bottom of the middle end of the cross bar 241, a limiting slider 25 is slidably connected between the top of the side plate 24 and the bottom of the cross bar 241, the limiting slider 25 is in an internal hollow state, and the limiting assembly 27 includes a No. 1 sliding member 271, the No. 1 sliding member 271 is in the shape of the letter U, and the No. 1 sliding member 271 is slidably connected to the inner side of the limiting slider 25, A sliding column 2713 is fixedly connected to the top of the end of the No. 1 sliding member 271, and the sliding column 2713 is slidably connected to the inner side of the limiting slider 25. A No. 1 square groove 2711 is opened on the inner sides of both sides of the No. 1 sliding member 271, and a No. 1 spring 2714 is arranged on the top of the No. 1 sliding member 271. Extension plates 2712 are fixedly connected to the outer walls of both sides of the No. 1 sliding member 271, and a No. 2 spring 272 is arranged on the top of the extension plate 2712. The two ends of the No. 2 spring 272 respectively abut against the top inner wall of the limiting slider 25 and the top of the extension plate 2712.

[0039] like Figure 2-Figure 8 As shown, the inner side of the limiting slider 25 is slidably connected with a No. 2 sliding member 273, a No. 1 spring 2714 is arranged between the No. 1 sliding member 271 and the No. 2 sliding member 273, and the outer walls of both sides of the No. 2 sliding member 273 are provided with No. 2 square grooves 2731, and the No. 2 square grooves 2731 have the same height as the No. 1 square groove 2711, and the top of the No. 2 sliding member 273 is fixedly connected with a buckle strip 275, and the width of the buckle strip 275 matches the width of the groove 2411, and the shape of the irregular groove 242 matches the shape of the No. 1 square groove 2711. The bottom shape of the No. 1 sliding member 271 is matched, and a connecting rod 274 is arranged between the No. 1 sliding member 271 and the No. 2 sliding member 273. The middle end of the connecting rod 274 is rotatably connected to the inner wall of the limiting sliding member 25, and both ends of the connecting rod 274 are fixedly connected with the No. 2 limiting column 2741. The diameter of the No. 2 limiting column 2741 is the same as the height of the No. 1 square groove 2711 and the No. 2 square groove 2731. The No. 2 limiting columns 2741 at both ends are respectively located on the inner sides of the No. 1 square groove 2711 and the No. 2 square groove 2731.

[0040] It can be seen from this that when cutting curved aluminum alloy profiles, Figure 1-Figure 4As shown, the staff places the curved aluminum alloy profile on the top of the grid plate 31 and conveys it to the right. At this time, the telescopic column 26 in the extended state blocks the input end of the aluminum alloy profile. At this time, the aluminum alloy profile in the conveyed state will drive the telescopic column 26 to slide to the right together and slowly shrink during the sliding process. As the height of the bent part of the telescopic column 26 decreases, it will gradually lose the blocking of the aluminum alloy profile, so that the aluminum alloy profile is completely placed on the top of the grid plate 31. At this time, one side of a part of the profile is a combination of a curved surface and a right-angle surface. At this time, after the curved surface of the profile is placed on the grid plate 31, the cutting head 113 is used to perform conventional cutting operations under the fixation of the telescopic column 26 and the No. 1 limiting column 114;

[0041] When the curved surface of the partially curved aluminum alloy profile is in the same direction as the concave surface of the grid plate 31, the telescopic columns 26 on both sides will extend on one side and contract on the other side during the conveying process. At this time, the bent portion of the telescopic column 26 on one side is located at the top of the profile, and the other side is located at the bottom of the profile, and will not block the profile. At this time, after the aluminum alloy profile is conveyed to the specified position, the transmission roller 211 rotates under the drive of the motor 21, and the rotating rod 23 rotates together with the threaded protruding strip 231 under the drive of the transmission belt 22. The rack 32, the rotating frame 3 and the grid plate 31 will also be driven to rotate together. At this time, the aluminum alloy profile will also rotate a certain angle under the rotation of the grid plate 31. However, under the influence of gravity and friction, if the rotation angle is too large, the aluminum alloy profile will slip, thereby affecting the cutting efficiency when the rotation angle is large. At this time, the telescopic columns 26 on both sides will be telescopic with the rotation direction of the rotating frame 3, and at the same time, under the restriction of the No. 1 limiting column 114, the rotation angle of the aluminum alloy profile is guaranteed to be the same as the rotation angle of the rotating frame 3 during the force rotation process.

[0042] In addition, in the process of pushing the telescopic column 26 to slide, the limiting slider 25 will be driven to slide together. When the limiting slider 25 slides to the same vertical plane position as the sliding frame 111, that is, the initial position of the sliding frame 111, at the same time, the No. 1 sliding member 271 moves downward under the elastic force of the No. 1 spring 2714 and penetrates into the irregular groove 242. At this time, the No. 1 sliding member 271 contacts the touch sensor, causing the telescopic column 26 to stop the telescopic movement and reach the specified position to limit the arc-shaped aluminum alloy profile. At the same time, in the process of the No. 1 sliding member 271 sliding downward, the No. 1 square groove 2711 will be used to lift the connecting rod 274 with the middle end position as the fulcrum to lift the No. 2 sliding member 273, so that the No. 2 sliding member 273 slides upward, and finally the No. 2 sliding member 273 drives the card The buckle strip 275 goes deep into the groove 2411 to limit the position of the limiting slider 25 and the telescopic column 26, so that the position of the telescopic column 26 and the sliding frame 111 are in the same vertical plane. At this time, the bending position of the telescopic columns 26 on both sides is also in the same vertical plane as the No. 1 limiting column 114. At this time, the telescopic column 26 at the top of the aluminum alloy profile will limit the profile height on one side, and the telescopic column 26 at the bottom of the aluminum alloy profile on the other side will fix the arc-shaped aluminum alloy profile with the No. 1 limiting column 114 (the end of the telescopic column 26 is used as the bottom support, and the No. 1 limiting column 114 is used for top fixing). At this time, the rotating frame 3 is controlled to rotate, and cooperates with the telescopic column 26 to complete some larger angle rotations, which can adapt to more angles of arc-shaped aluminum alloy profiles;

[0043] It should be noted that the initial position of the sliding frame 111 is located at the middle end position of the electric slide rail 11, and the initial positions of the limiting slider 25 and the telescopic column 26 are at the leftmost end position. After the telescopic column 26 stops moving after reaching the middle end position, when the motor 21 drives the rotating frame 3 to rotate, the telescopic column 26 will also be extended and retracted again. When the rotating frame 3 rotates, one side of the rotating frame 3 will gradually lower, while the other side will gradually rise. At this time, the telescopic column 26 on the raised side will also gradually rise. Conversely, the same is true for the telescopic column 26 on the other side. It is only necessary to ensure that the height of the bent part of the telescopic column 26 is consistent with the height of the two sides of the rotating frame 3 after rotation.

[0044] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A laser cutting device for processing aluminum alloy profiles, comprising a guard plate (1) and a guide base (2), characterized in that: The guard plate (1) is fixedly connected to electric slide rails (11) on both sides, the outer side of the electric slide rail (11) is slidably connected to a sliding frame (111), the top outer wall of the sliding frame (111) is slidably connected to a sliding block (112), and the bottom of the sliding block (112) is telescopically connected to a cutting head (113); The guide base (2) is fixedly connected to the inner wall of the guard plate (1); the top of the guide base (2) is slidably connected to a rotating frame (3); the top of the rotating frame (3) is fixedly connected to a grid plate (31); and the bottom of the outer wall of the rotating frame (3) is fixedly connected to a rack (32); The top of the guide base (2) is fixedly connected to a motor (21), the top of the guide base (2) is rotatably connected to a rotating rod (23), both side outer walls of the guide base (2) are fixedly connected to side plates (24), the top of the side plates (24) is slidably connected to a limiting slider (25), and a limiting component (27) is provided on the inner side of the limiting slider (25).

2. The laser cutting equipment for aluminum alloy profile processing according to claim 1, characterized in that: A first limiting column (114) is fixedly connected to both sides of the bottom of the upper end of the sliding frame (111), and a telescopic column (26) is fixedly connected to the outer wall of the limiting sliding block (25), and the telescopic column (26) and the first limiting column (114) are located on the same vertical plane.

3. The laser cutting equipment for aluminum alloy profile processing according to claim 1, characterized in that: The output end of the motor (21) is fixedly connected to a transmission roller (211), the outer wall of the transmission roller (211) is sleeved with a transmission belt (22), and the other end of the transmission belt (22) is sleeved on the outer wall of the rotating rod (23).

4. The laser cutting equipment for aluminum alloy profile processing according to claim 1, characterized in that: A threaded protrusion strip (231) is fixedly connected to the outer wall of the rotating rod (23), and the threaded protrusion strip (231) is meshedly connected to the rack (32).

5. The laser cutting equipment for aluminum alloy profile processing according to claim 4, characterized in that: The top of the side plate (24) is fixedly connected to a cross bar (241), the top of the side plate (24) is provided with an irregular groove (242), the top of the irregular groove (242) is provided with a touch sensor, the bottom position of the middle end of the cross bar (241) is provided with a groove (2411), and the limiting slider (25) is slidably connected to the top of the side plate (24) and the bottom position of the cross bar (241).

6. The laser cutting equipment for aluminum alloy profile processing according to claim 5, characterized in that: The limiting slider (25) is in an internal hollow state. The limiting assembly (27) includes a No. 1 sliding member (271). The No. 1 sliding member (271) is in a U-shape and is slidably connected to the inner side of the limiting slider (25). A sliding column (2713) is fixedly connected to the top of the end of the No. 1 sliding member (271). The sliding column (2713) is slidably connected to the inner side of the limiting slider (25). A square groove (2711) is provided on the inner sides of both sides of the sliding member (271), a spring (2714) is arranged on the top of the sliding member (271), an extension plate (2712) is fixedly connected to the outer walls of both sides of the sliding member (271), a spring (272) is arranged on the top of the extension plate (2712), and the two ends of the spring (272) are respectively against the top inner wall of the limiting sliding member (25) and the top of the extension plate (2712).

7. The laser cutting equipment for aluminum alloy profile processing according to claim 6, characterized in that: The inner side of the limiting slider (25) is slidably connected to a No. 2 slider (273), the No. 1 spring (2714) is arranged between the No. 1 slider (271) and the No. 2 slider (273), and the outer walls on both sides of the No. 2 slider (273) are provided with a No. 2 square groove (2731), and the No. 2 square groove (2731) has the same height as the No. 1 square groove (2711).

8. The laser cutting equipment for aluminum alloy profile processing according to claim 7, characterized in that: A buckle strip (275) is fixedly connected to the top of the second sliding member (273), and the width of the buckle strip (275) matches the width of the groove (2411).

9. The laser cutting equipment for aluminum alloy profile processing according to claim 8, characterized in that: The shape of the irregular groove (242) matches the bottom shape of the No. 1 sliding member (271).

10. The laser cutting equipment for aluminum alloy profile processing according to claim 9, characterized in that: A connecting rod (274) is arranged between the No. 1 sliding member (271) and the No. 2 sliding member (273), the middle end of the connecting rod (274) is rotatably connected to the inner wall of the limiting sliding block (25), and both ends of the connecting rod (274) are fixedly connected to the No. 2 limiting column (2741), the diameter of the No. 2 limiting column (2741) is the same as the height of the No. 1 square groove (2711) and the No. 2 square groove (2731), and the No. 2 limiting columns (2741) at both ends are respectively located on the inner sides of the No. 1 square groove (2711) and the No. 2 square groove (2731).

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