A fully optically-utilized orbital coated umbrella frame

By designing a fully-utilized optical machine orbital coating umbrella frame supported by a ring array connecting ribs and a bottom support, the problems of uneven coating and insufficient adaptability in the existing technology are solved, achieving a high-efficiency and low-cost coating effect, which is suitable for large-size and irregularly shaped optical components.

CN121023451BActive Publication Date: 2026-06-30GUANGDONG ZHENHUA TECH CO LTD

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
GUANGDONG ZHENHUA TECH CO LTD
Filing Date
2025-08-22
Publication Date
2026-06-30

AI Technical Summary

Technical Problem

Existing vacuum optical coating umbrella frames have problems such as connecting ribs obscuring the edge area of ​​the umbrella blades and the large rotating flange obscuring the lower edge, resulting in uneven coating. This makes it difficult to meet the coating requirements of high-precision optical components and cannot adapt to the coating needs of large-sized or irregularly shaped parts.

Method used

A fully utilized optical revolving coating umbrella frame was designed. The edge of the umbrella slats is supported by a ring array of connecting ribs and bottom support components, eliminating physical obstruction, ensuring uniform coverage of the particle beam, adapting to umbrella slats of different specifications and wear, and improving coating capacity and equipment utilization.

Benefits of technology

It achieves uniform coverage of the coating particle beam, improves coating capacity and yield, reduces production costs and energy consumption, expands the equipment's applicability, and meets the coating needs of large-size and irregularly shaped optical components.

✦ Generated by Eureka AI based on patent content.

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Abstract

This invention relates to the field of vacuum coating equipment, and in particular to a fully-utilized optical rotation coating umbrella frame, comprising a central output shaft, multiple connecting ribs, and multiple base supports. Multiple umbrella-shaped sections are arranged in a circular array around the central output shaft, with their inner edges overlapping the central output shaft. Multiple connecting ribs are arranged in a circular array above the multiple umbrella-shaped sections, with one end connected to the central output shaft and the other end extending to the outer edge of the umbrella-shaped section. Multiple base supports are respectively connected to the ends of the multiple connecting ribs located at the outer edge of the umbrella-shaped sections, with each base support positioned between two adjacent umbrella-shaped sections and abutting against the outer edge of the umbrella-shaped section. This design eliminates physical obstruction of the edge areas of the umbrella-shaped sections, significantly improving the coating capacity per unit time, avoiding interference from the rotating flange on the lower edge of the umbrella-shaped sections, and ensuring that the particle beam emitted by the target material at the bottom of the vacuum chamber uniformly covers the entire area of ​​the umbrella-shaped sections, overcoming the structural limitations of traditional fixed-obstruction umbrella frames.
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Description

Technical Field

[0001] This invention relates to the field of vacuum coating equipment, and in particular to a coating umbrella frame that fully utilizes the orbital rotation of an optical machine. Background Technology

[0002] In the field of vacuum optical coating, large-scale vacuum optical coating umbrella frames are key equipment for achieving uniform coating of workpieces. Their conventional structure mainly consists of a central rotary input shaft, a large revolving flange, connecting ribs, and multiple umbrella-shaped sections. The central rotary input shaft, serving as the core of power transmission, is connected to an external drive device; the large revolving flange is fixed to the top of the central shaft by welding or bolting; several connecting ribs are radially distributed, one end connecting to the edge of the large revolving flange, and the other end extending outwards, forming a radial skeleton structure with the central shaft. Multiple fan-shaped or annular umbrella-shaped sections are laid on the skeleton, positioned by the upper surface of the connecting ribs and the upper edge of the large revolving flange. The workpiece is fixed to the upper surface of the umbrella-shaped sections by clamps and completes the coating process by revolving around the central shaft within the vacuum chamber with the umbrella frame.

[0003] Existing technologies have significant shortcomings. Firstly, the connecting ribs, being solid rods, run through the gaps between the umbrella-shaped sections. During the coating process, the coating particles emitted by the electron gun or target travel in a straight line, and the connecting ribs physically block the edge area of ​​the umbrella-shaped section near itself, resulting in a significant reduction in the amount of coating particles deposited in that area, making it impossible to form an effective film layer. Secondly, the upper surface of the orbital flange is in direct contact with the lower edge of the umbrella-shaped section, and its edge thickness blocks the particle beam from the target material at the bottom of the vacuum chamber, leading to a coating blind zone within the lower edge area of ​​the umbrella-shaped section, making it difficult to meet the coating requirements of high-precision optical components.

[0004] Furthermore, the fixed shielding structure of the existing umbrella frame cannot eliminate the impact by adjusting the process parameters. When facing the coating requirements of large-sized or irregularly shaped parts, more clearance space needs to be reserved, which further reduces the utilization rate of the equipment. At the same time, the existing umbrella frame does not have the function of flexibly adjusting and limiting the edge of the umbrella slats. It is usually only suitable for umbrella slats of a single specification. When facing different specifications or changes in specifications and dimensions due to wear and other reasons, it cannot continue to achieve stable limiting and fixing. Summary of the Invention

[0005] Based on this, it is necessary to provide a fully utilized optical machine orbiting coating umbrella frame to address the above-mentioned technical problems. This eliminates physical obstruction of the edge area of ​​the umbrella, significantly improves the coating capacity per unit time, avoids the obstruction and interference of the orbiting large flange on the lower edge of the umbrella, and ensures that the particle beam emitted by the target material at the bottom of the vacuum chamber uniformly covers the entire area of ​​the umbrella.

[0006] This invention provides a fully-utilized optical rotating coated umbrella frame, comprising:

[0007] A central output shaft is surrounded by multiple umbrella-shaped fins arranged in a circular array, with the inner edges of the umbrella-shaped fins overlapping the central output shaft.

[0008] Multiple connecting ribs are arranged in a ring array above multiple umbrella slats. One end of each connecting rib is connected to the central output shaft, and the other end of each connecting rib extends to the outer edge of the umbrella slats.

[0009] Multiple bottom support members are respectively connected to one end of the multiple connecting ribs located at the outer edge of the umbrella slats. Each bottom support member is located between two adjacent umbrella slats and abuts against the outer edge of the umbrella slats.

[0010] In one embodiment, the central output shaft includes a fixed tube, a mounting tube, and an adjusting seat; the fixed tube is used to fix it to the driving end of the driving component, the mounting tube is connected below the fixed tube and connected to the connecting rib, the adjusting seat is rotatably mounted on the bottom end of the mounting tube, and the umbrella-shaped fin overlaps on the adjusting seat and is snapped between the adjusting seat and the mounting tube.

[0011] In one embodiment, the adjusting seat includes an inner mounting tube and an annular plate; an annular cut is provided at the connection between the outer ring of the mounting tube and the bottom surface, the inner mounting tube is threaded onto the bottom end of the mounting tube, and the annular plate is sleeved on the bottom end of the inner mounting tube.

[0012] In one embodiment, the annular plate has a plurality of first mounting holes on its surface, which are arranged in a ring array. The outer ring of the annular plate has a plurality of second mounting holes, the central axis of which coincides with the radius of the annular plate. Each second mounting hole passes through one of the first mounting holes. A first rotating rod is rotatably mounted in each second mounting hole, and a first rotating wheel is sleeved on each first rotating rod.

[0013] In one embodiment, the connection between the outer ring and the end face of the first rotating wheel is set as an inclined surface, and the outer ring of the first rotating wheel has a plurality of grooves, with a top block formed between two adjacent grooves.

[0014] In one embodiment, the connecting rib includes a vertical plate, a flat plate, and a diagonal brace; one end of the vertical plate is horizontally connected to the fixing tube, and the other end of the vertical plate extends downward at an angle to the outer edge of the umbrella fin; the flat plate is fitted to the bottom surface of the vertical plate, and the diagonal brace is disposed on the lower surface of the bend of the flat plate.

[0015] In one embodiment, the base support includes a connecting block and a pad; the pad is connected to the lower surface of the connecting block, a first slot is formed on the surface of the connecting block, the first slot extends to the other surface of the connecting block, a second slot is formed at the top of the connecting block, the second slot communicates with the first slot, the vertical plate is engaged in the second slot, the flat plate is engaged in the first slot, and a baffle is provided at one end of the flat plate, the baffle is attached to one side of the connecting plate.

[0016] In one embodiment, a fifth mounting hole is provided on each of the opposite sides of the second slot, and a fourth mounting hole is provided on the top surface of the connecting block. The fourth mounting hole and the fifth mounting hole are connected. A second rotating rod is rotatably installed in the fifth mounting hole, and a second rotating wheel is sleeved on the second rotating rod.

[0017] In one embodiment, the upper surface of the pad is provided with a limiting protrusion, which is used to abut between two adjacent umbrella slats.

[0018] In one embodiment, the side of the flat plate has multiple limiting grooves arranged in a linear array, and the side of the vertical plate has multiple third mounting holes arranged in a linear array. Insert rods are installed in two adjacent third mounting holes, and the two insert rods are connected by a connecting pipe. A screw is threaded into the connecting pipe. A bent rod is provided on the vertical plate. The two ends of the bent rod have parallel central axes and are clamped in two of the limiting grooves. The screw abuts against the end of the bent rod.

[0019] The aforementioned optical machine orbital coating umbrella frame utilizes connecting ribs welded around the central output shaft to form a ring array. A bottom support is welded to one end of each connecting rib, supporting the junction and outer edge of adjacent umbrella sections. This eliminates physical obstruction of the umbrella section edge area, significantly improving the coating capacity per unit time. It avoids interference from the orbital flange on the lower edge of the umbrella section, ensuring that the particle beam emitted by the target material at the bottom of the vacuum chamber uniformly covers the entire umbrella section. This design overcomes the structural limitations of traditional fixed-obstruction umbrella frames, adapting to the coating needs of large-size and irregularly shaped optical components. It reduces ineffective space reserved to avoid obstruction, expands the equipment's applicability, and improves overall equipment utilization. Furthermore, the increased capacity and coating yield effectively reduce production time and raw material waste per unit product. The optimized structure makes the coating process more efficient, reducing energy consumption in auxiliary processes such as vacuuming and heating, achieving a dual reduction in production costs and energy consumption. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 A three-dimensional structural diagram of the coated umbrella frame provided by the present invention;

[0022] Figure 2 A cross-sectional structural diagram of the coated umbrella frame provided by the present invention;

[0023] Figure 3 A schematic diagram of the structure of the center output shaft provided by the present invention;

[0024] Figure 4 This is a schematic diagram of the structure of the adjustment seat provided by the present invention;

[0025] Figure 5 This is a schematic diagram of the structure of the bottom support member provided by the present invention;

[0026] Figure 6 This is a partial structural diagram of the connecting rib provided by the present invention.

[0027] Figure label:

[0028] 10. Umbrella flap; 100. Center output shaft; 110. Fixing tube; 111. Annular notch; 120. Mounting tube; 130. Adjusting seat; 131. Inner mounting tube; 132. Annular plate; 1321. First mounting hole; 1322. Second mounting hole; 133. First rotating rod; 134. First rotating wheel; 1341. Groove; 135. Top block; 200. Connecting rib; 210. Vertical plate; 211. Third mounting hole; 22. 0. Flat plate; 221. Limiting groove; 230. Diagonal brace; 240. Baffle; 300. Bottom support; 310. Connecting block; 311. First slot; 312. Second slot; 313. Fourth mounting hole; 314. Fifth mounting hole; 320. Pad; 330. Limiting protrusion; 340. Second rotating rod; 350. Second rotating wheel; 410. Insert rod; 420. Connecting pipe; 430. Screw; 440. Bent rod. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The following is combined Figures 1 to 6 This invention describes a fully-utilized optical rotating coated umbrella frame.

[0031] like Figure 1 and Figure 2 As shown, in one embodiment, a fully-utilized optical revolving coated umbrella frame includes a central output shaft 100, multiple connecting ribs 200, and multiple bottom support members 300. Multiple umbrella slats 10 are arranged in a circular array around the central output shaft 100, with the inner edges of the umbrella slats 10 overlapping the central output shaft 100. Multiple connecting ribs 200 are arranged in a circular array above the multiple umbrella slats 10, with one end of each connecting rib connected to the central output shaft 100 and the other end extending to the outer edge of the umbrella slats 10. Multiple bottom support members 300 are respectively connected to the ends of the multiple connecting ribs 200 located at the outer edge of the umbrella slats 10, with each bottom support member 300 located between two adjacent umbrella slats 10, and abutting against the outer edge of the umbrella slats 10.

[0032] The aforementioned optical machine orbital coating umbrella frame utilizes connecting ribs 200 welded around the central output shaft 100 to form a ring array. A bottom support 300 is welded to one end of each connecting rib 200. This bottom support 300 supports the junction and outer edge of adjacent umbrella sections 10, eliminating physical obstruction of the edge area of ​​the umbrella section 10. This significantly improves the coating capacity per unit time, avoids interference from the orbital flange on the lower edge of the umbrella section 10, and ensures that the particle beam emitted by the target material at the bottom of the vacuum chamber uniformly covers the entire area of ​​the umbrella section 10. This design breaks through the structural limitations of traditional fixed-obstruction umbrella frames, adapting to the coating needs of large-size and irregularly shaped optical components. It reduces the ineffective space reserved to avoid obstruction, expands the equipment's applicability, and improves the overall utilization rate of the equipment. Furthermore, the increased capacity and coating yield effectively reduce the production time and raw material loss per unit product. The optimized structure makes the coating process more efficient, reducing energy consumption in auxiliary processes such as vacuuming and heating of the vacuum chamber, achieving a dual reduction in production costs and energy consumption.

[0033] like Figure 3As shown, in one embodiment, the center output shaft 100 includes a fixed tube 110, a mounting tube 120, and an adjusting seat 130; the fixed tube 110 is used to fix to the driving end of the driving component, the mounting tube 120 is connected below the fixed tube 110, the mounting tube 120 is connected to the connecting rib 200, the adjusting seat 130 is rotatably mounted on the bottom end of the mounting tube 120, the umbrella 10 overlaps on the adjusting seat 130 and is snapped between the adjusting seat 130 and the mounting tube 120.

[0034] Specifically, the adjusting seat 130 includes an inner mounting tube 131 and an annular plate 132; an annular cut 111 is provided at the connection between the outer ring of the mounting tube 120 and the bottom surface, the inner mounting tube 131 is threaded onto the bottom end of the mounting tube 120, and the annular plate 132 is sleeved on the bottom end of the inner mounting tube 131.

[0035] The multiple umbrella blades 10 arranged in a ring array can form a hemispherical surface, and the inner ring of the surface overlaps the adjusting seat 130 and is fixed in a designated position by the adjusting seat 130.

[0036] like Figure 4 As shown, in one embodiment, the annular plate 132 has a plurality of first mounting holes 1321 on its surface, which are arranged in a ring array. The annular plate 132 has a plurality of second mounting holes 1322 on its outer ring. The central axis of the second mounting holes 1322 coincides with the radius of the annular plate 132. Each second mounting hole 1322 passes through a first mounting hole 1321. A first rotating rod 133 is rotatably installed in each second mounting hole 1322. A first rotating wheel 134 is sleeved on each first rotating rod 133.

[0037] Specifically, the surface of the first rotating wheel 134 protrudes from the upper surface of the annular plate 132, and the first rotating wheel 134 is located below the annular cut 111. The annular cut 111 is used to provide a position for the snap-fit ​​of the umbrella slat 10. The lower surface of the inner edge of the umbrella slat 10 overlaps the first rotating wheel 134. When the inner edge of the umbrella slat 10 is limited, the annular plate 132 is rotated. Since the inner mounting tube 131 is threaded in the fixing tube 110, the annular plate 132 will move upward and rotate during the movement, and finally clamp the inner edge of the umbrella slat 10 in the designated position.

[0038] In one embodiment, the connection between the outer ring and the end face of the first rotating wheel 134 is set as an inclined surface, and the outer ring of the first rotating wheel 134 is provided with a plurality of grooves 1341, and a top block 135 is formed between two adjacent grooves 1341.

[0039] Specifically, the first rotating wheel 134 is preferably made of rubber material, and since the two ends of the first rotating wheel 134 are provided with inclined surfaces and the outer ring is provided with grooves 1341, it forms a top block 135 part with a small area. The top block 135 part can effectively abut against the connection of adjacent umbrella slats 10, thereby achieving further positioning of the umbrella slats 10.

[0040] In one embodiment, the connecting rib 200 includes a vertical plate 210, a flat plate 220, and a diagonal brace 230; one end of the vertical plate 210 is horizontally connected to the fixing pipe 110, and the other end of the vertical plate 210 extends downward at an angle to the outer edge of the umbrella slat 10; the flat plate 220 is fitted to the bottom surface of the vertical plate 210; and the diagonal brace 230 is disposed on the lower surface of the bend of the flat plate 220.

[0041] Furthermore, such as Figure 5 As shown, in one embodiment, the bottom support 300 includes a connecting block 310 and a pad 320; the pad 320 is connected to the lower surface of the connecting block 310, a first slot 311 is formed on the surface of the connecting block 310, the first slot 311 extends to the other surface of the connecting block 310, a second slot 312 is formed at the top of the connecting block 310, the second slot 312 communicates with the first slot 311, the vertical plate 210 is engaged in the second slot 312, the flat plate 220 is engaged in the first slot 311, a baffle 240 is provided at one end of the flat plate 220, and the baffle 240 is attached to one side of the connecting plate.

[0042] Specifically, by opening a first slot 311 and a second slot 312 on the connecting block 310, and by engaging the first slot 311 and the second slot 312 with the flat plate 220 and the vertical plate 210 respectively, the bottom support 300 can move along the length direction of the flat plate 220, thereby adapting to the installation of umbrella slats 10 of different sizes.

[0043] In one embodiment, the second slot 312 has a fifth mounting hole 314 on each of its opposite sides, and the top surface of the connecting block 310 has a fourth mounting hole 313. The fourth mounting hole 313 and the fifth mounting hole 314 are connected. A second rotating rod 340 is rotatably installed in the fifth mounting hole 314, and a second rotating wheel 350 is sleeved on the second rotating rod 340.

[0044] Specifically, in order to make it easier to move the bottom support 300, a second rotating wheel 350 is set at the connection between the bottom support 300 and the connecting rib 200, thereby replacing the moving friction with a rotational friction method, making adjustment more convenient.

[0045] In one embodiment, a limiting protrusion 330 is provided on the upper surface of the pad 320, which is used to abut between two adjacent umbrella slats 10.

[0046] Specifically, the limiting protrusion 330 is preferably made of rubber material, and the limiting protrusion 330 is used to engage with the connection between two adjacent umbrella slats 10, thereby achieving further limiting of the umbrella slats 10.

[0047] like Figure 6 As shown, in one embodiment, the side of the flat plate 220 is provided with a plurality of limiting grooves 221 in a linear array, and the side of the vertical plate 210 is provided with a plurality of third mounting holes 211 in a linear array. A rod 410 is installed in two adjacent third mounting holes 211. The two rods 410 are connected by a connecting pipe 420. A screw 430 is threaded in the connecting pipe 420. A bent rod 440 is provided on the vertical plate 210. The two ends of the bent rod 440 are parallel to each other and are clamped in two limiting grooves 221. The screw 430 abuts against the end of the bent rod 440.

[0048] Specifically, the bent rod 440 is elastic, and under normal conditions, both ends of the bent rod 440 are respectively clamped in two oppositely arranged limiting grooves 221.

[0049] It should be noted that the adjustable bottom support 300 can achieve the support and limit of the umbrella slats 10. As long as the size of the umbrella slats 10 is within a certain range, and regardless of whether the umbrella slats 10 are worn or otherwise affect the size, the adjustable bottom support 300 can achieve stable limiting of the umbrella slats 10.

[0050] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A fully optically-utilized orbital coated umbrella frame, characterized in that, include: A central output shaft has multiple umbrella-shaped fins arranged in a circular array around its periphery. The inner edges of the umbrella-shaped fins overlap the central output shaft. The central output shaft includes a fixed tube, a mounting tube, and an adjusting seat. The fixed tube is used to fix the shaft to the driving end of the driving component. The mounting tube is connected to the lower part of the fixed tube and is connected to a connecting rib. The adjusting seat is rotatably mounted on the bottom end of the mounting tube. The umbrella-shaped fins overlap the adjusting seat and are snapped between the adjusting seat and the mounting tube. Multiple connecting ribs are arranged in a circular array above multiple umbrella fins. One end of each connecting rib is connected to the central output shaft, and the other end of each connecting rib extends to the outer edge of the umbrella fin. Each connecting rib includes a vertical plate, a flat plate, and a diagonal brace. One end of the vertical plate is horizontally connected to the fixing tube, and the other end of the vertical plate extends downward at an angle to the outer edge of the umbrella fin. The flat plate is fitted against the bottom surface of the vertical plate, and the diagonal brace is located on the lower surface of the bend of the flat plate. Multiple bottom support members are respectively connected to one end of the multiple connecting ribs located at the outer edge of the umbrella slats. Each bottom support member is located between two adjacent umbrella slats and abuts against the outer edge of the umbrella slats. Each bottom support member includes a connecting block and a pad. The pad is connected to the lower surface of the connecting block. A first slot is formed on the surface of the connecting block, extending to the other surface of the connecting block. A second slot is formed at the top of the connecting block, communicating with the first slot. The vertical plate is engaged in the second slot, and the flat plate is engaged in the first slot. A baffle is provided at one end of the flat plate, and the baffle is attached to one side of the connecting plate.

2. The fully-utilized optical revolving coated umbrella frame according to claim 1, characterized in that, The adjusting seat includes an inner mounting tube and an annular plate; an annular cut is provided at the connection between the outer ring of the mounting tube and the bottom surface; the inner mounting tube is threaded onto the bottom end of the mounting tube; and the annular plate is sleeved on the bottom end of the inner mounting tube.

3. The fully-utilized optical revolving coated umbrella frame according to claim 2, characterized in that, The annular plate has multiple first mounting holes on its surface, arranged in a circular array. The outer ring of the annular plate has multiple second mounting holes, the central axis of which coincides with the radius of the annular plate. Each second mounting hole passes through one of the first mounting holes. A first rotating rod is rotatably installed in each second mounting hole, and a first rotating wheel is fitted on each first rotating rod.

4. The fully-utilized optical revolving coated umbrella frame according to claim 3, characterized in that, The outer ring and end face of the first rotating wheel are connected by a bevel. The outer ring of the first rotating wheel has multiple grooves, and a top block is formed between two adjacent grooves.

5. The fully-utilized optical revolving coated umbrella frame according to claim 1, characterized in that, The second slot has a fifth mounting hole on each of its two opposite sides, and the top surface of the connecting block has a fourth mounting hole. The fourth mounting hole and the fifth mounting hole are connected. A second rotating rod is rotatably installed in the fifth mounting hole, and a second rotating wheel is sleeved on the second rotating rod.

6. The fully-utilized optical revolving coated umbrella frame according to claim 1, characterized in that, The upper surface of the pad is provided with a limiting protrusion, which is used to abut between two adjacent umbrella slats.

7. The fully-utilized optical revolving coated umbrella frame according to claim 1, characterized in that, The flat plate has multiple limiting grooves arranged in a linear array on its side, and the vertical plate has multiple third mounting holes arranged in a linear array on its side. Insert rods are installed in two adjacent third mounting holes, and the two insert rods are connected by a connecting pipe. A screw is threaded into the connecting pipe. A bent rod is provided on the vertical plate. The two ends of the bent rod have parallel central axes and are clamped in two of the limiting grooves. The screw abuts against the end of the bent rod.