A non-planar inter-bulk misregistration angle measurement apparatus
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TENG ZE DIAN GONG SHANG HAI YOU XIAN GONG SI
- Filing Date
- 2025-11-01
- Publication Date
- 2026-08-07
AI Technical Summary
[0002]在冰箱、冷柜等制冷器的运行过程中,冷热交换器表面易因温度差异形成霜冻,若不及时处理会影响设备的制冷效率和实用寿命
1.先通过移动调整机构调节定位机构与移动调整机构之间的距离,以适配玻璃管两端橡胶帽之间的间距;然后通过定位机构对一端橡胶帽进行定位,再通过移动调整机构对另一端的橡胶帽进行定位,随后通过检测机构实时检测另一端橡胶帽的转动状态,最后角度指示机构显示两端橡胶帽之间的相对角度;通过定位机构和移动调整机构的配合,能够对玻璃管两端的橡胶管进行稳定且精准的定位,而检测机构直接作用于定位后的橡胶帽,结合角度指示机构的实时转换,有效提高了两端橡胶帽的相对角度检测的准确性,且结构简单、耐用,检查操作方便,非常适合大批量作业,可极大提升作业效率,降低生产成本;
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Figure CN224608363U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of angle measuring equipment technology, and in particular to a non-planar internal misalignment angle measuring device. Background Technology
[0002] During the operation of refrigerators, freezers, and other refrigeration units, frost can easily form on the surface of the heat exchanger due to temperature differences. If not dealt with in time, this can affect the cooling efficiency and service life of the equipment. To prevent frost formation on the heat exchanger, glass tube heaters are usually installed for defrosting. However, during the defrosting process, defrosting water droplets may fall onto the glass tube heaters, potentially damaging them. Therefore, a baffle plate needs to be installed above the glass tube heaters.
[0003] The baffle plate is installed on the rubber caps at both ends of the glass tube heater. If the rubber caps at both ends of the glass tube heater are misaligned or skewed too much, the baffle plate will not be able to be installed smoothly; or after the baffle plate is installed, it will be twisted and deformed due to uneven force, resulting in the loss of the water-blocking function. Therefore, it is necessary to check the misalignment angle between the rubber caps at both ends of the glass tube heater.
[0004] In related technologies, after installing the rubber caps at both ends of the glass tube heater, the relative angle between the two rubber caps is usually detected by manual visual inspection. However, due to the error in human visual judgment, it is difficult to accurately identify the relative angle between the two rubber caps, so the accuracy of the detection results obtained by this method is low. Utility Model Content
[0005] To improve the accuracy of relative angle detection of the rubber caps at both ends of a glass tube, this application provides a non-planar internal misalignment angle measuring device, which has the effect of improving the accuracy of relative angle detection of the rubber caps at both ends of a glass tube.
[0006] The non-planar internal misalignment angle measuring device provided in this application adopts the following technical solution: A non-planar internal misalignment angle measuring device includes a base with a groove along its length. A positioning mechanism is mounted on the base and fixed at one end of the groove. The positioning mechanism is used to position a rubber cap at one end of a glass tube. A movable adjustment mechanism is mounted on the base and slidably connected within the groove. The movable adjustment mechanism is positioned opposite to the positioning mechanism and is used to position a rubber cap at the other end of the glass tube. A detection mechanism is mounted on the movable adjustment mechanism to detect the rubber cap on the movable adjustment mechanism. An angle indicating mechanism is mounted on the movable adjustment mechanism to display the relative angle between the two ends of the rubber tube.
[0007] By adopting the above technical solution, the distance between the positioning mechanism and the moving adjustment mechanism is first adjusted by the moving adjustment mechanism to match the spacing between the rubber caps at both ends of the glass tube. Then, the positioning mechanism positions one rubber cap, and the moving adjustment mechanism positions the other rubber cap. Subsequently, the detection mechanism detects the rotation status of the other rubber cap in real time, and finally, the angle indicator mechanism displays the relative angle between the two rubber caps. Through the cooperation of the positioning mechanism and the moving adjustment mechanism, the rubber tubes at both ends of the glass tube can be stably and accurately positioned. The detection mechanism acts directly on the positioned rubber caps, and combined with the real-time switching of the angle indicator mechanism, the accuracy of the relative angle detection of the two rubber caps is effectively improved. The structure is simple, durable, and easy to inspect and operate, making it very suitable for mass production, which can greatly improve work efficiency and reduce production costs.
[0008] Optionally, the positioning mechanism includes a placement block and a first positioning block disposed on the placement block. The placement block is fixedly disposed at one end of the groove, and both sides of the placement block abut against the inner wall of the groove. The first positioning block is located on the top of the placement block near the moving adjustment mechanism. The first positioning block abuts against the inner side of the rubber cap, and the top plane of the placement block abuts against the bottom plane of the rubber cap.
[0009] By adopting the above technical solution, the two sides of the placement block abut against the inner wall of the groove, which effectively reduces the displacement of the placement block and provides a stable foundation for the positioning of the rubber cap at one end of the glass tube; by abutting the first positioning block against the inner side of the rubber cap, the lateral displacement of the rubber cap during the measurement process is effectively reduced, thereby improving the stability of the rubber cap positioning.
[0010] Optionally, the moving adjustment mechanism includes a moving block and a second positioning block disposed on the moving block. The moving block is slidably connected in the groove. The moving block is disposed opposite to the placement block. The second positioning block is located above the moving block. The second positioning block is disposed opposite to the first positioning block. The second positioning block abuts against the inner side of the rubber cap.
[0011] By adopting the above technical solution, the moving block moves along the length of the groove, which makes it easy to adjust the distance between it and the placement block, and is beneficial to adapt to the positioning requirements of glass tubes of different lengths; the second positioning block abuts against the inner side of the rubber cap, forming a lateral limit on the rubber cap, so that the position of the rubber cap remains stable.
[0012] Optionally, a pressure plate is provided on the base along the length direction. The pressure plate is detachably fixed in the groove. One side wall of the pressure plate abuts against the inner wall of the groove. A fixing groove is opened at the bottom of the movable block. The pressure plate passes through the fixing groove. The other side wall of the pressure plate abuts against the inner wall of the fixing groove. The contact surfaces of the other side wall of the pressure plate and the fixing groove are both inclined surfaces.
[0013] By adopting the above technical solution, when the pressure plate is fixed, the inclined surface of the pressure plate generates a lateral force on the moving block, so that the side of the moving block away from the pressure plate is tightly abutted against the inner wall of the groove, which can ensure that the moving block and the placement block are on the same horizontal line, thereby improving the accuracy of the position of the moving block.
[0014] Optionally, the top of the movable block has a detection groove along its length, the detection mechanism includes a detection plate, the detection plate is located in the detection groove, the detection plate is used to place the rubber cap, and support columns are symmetrically arranged at both ends of the detection plate. The top of the movable block has symmetrically arranged receiving grooves, the two receiving grooves are respectively located on both sides of the detection groove, and the support columns are located in the receiving grooves.
[0015] By adopting the above technical solution, when installing the detection plate, the detection plate is placed in the detection groove, and the support column is embedded in the receiving groove. The support column provides support and positioning for the detection plate, reducing horizontal displacement of the detection plate. The detection plate provides a placement space for the rubber cap. When the rubber cap on the detection plate is misaligned with the rubber cap on the placement block, the detection plate rotates in the receiving groove through the support column, and the top plane of the detection plate fits with the bottom plane of the rubber cap. The rotation angle of the detection plate reflects the misalignment angle of the rubber cap in real time.
[0016] Optionally, the angle indicating mechanism includes a pointer and a dial. The pointer is located on a support column on the side away from the placement block, and the end of the pointer away from the support column is bent in a direction away from the base. The dial is located on the side of the moving block away from the placement block, and one end of the dial is bent in a direction away from the base. An angle mark is provided on the dial, and there is a gap between the pointer and the dial.
[0017] By adopting the above technical solution, the deflection of the detection plate drives the support column to rotate synchronously, thereby causing the pointer to deflect at an angle. The operator can directly read the angle mark on the dial pointed to by the pointer, which makes it easy to obtain the misalignment angle value of the rubber caps at both ends of the glass tube.
[0018] Optionally, the angle indicating mechanism includes an angle sensor located on the side of the moving block away from the placement block, the angle sensor being used to display the rotation angle of the detection plate.
[0019] By adopting the above technical solution, the angle sensor directly displays the rotation angle value of the detection plate, which makes it convenient for operators to directly read the misalignment angle value of the rubber caps at both ends of the glass tube.
[0020] Optionally, the base is equipped with a controller and an alarm light. The controller is connected to an angle sensor, and the alarm light is connected to the controller. When the rotation angle of the detection plate exceeds a specified value, the alarm light flashes.
[0021] By adopting the above technical solution, the angle sensor transmits the rotation angle of the detection plate to the controller. When the rotation angle exceeds the specified value, it means that the misalignment angle of the rubber caps at both ends of the detection plate does not meet the requirements. At this time, the controller transmits the signal to the warning light, and the warning light starts to flash to remind the operator that there is an angle problem with the rubber caps at both ends of the glass tube.
[0022] In summary, this application includes at least one of the following beneficial technical effects: 1. First, the distance between the positioning mechanism and the moving adjustment mechanism is adjusted by the moving adjustment mechanism to match the spacing between the rubber caps at both ends of the glass tube. Then, the positioning mechanism positions one rubber cap, and the moving adjustment mechanism positions the other rubber cap. Subsequently, the detection mechanism detects the rotation status of the other rubber cap in real time. Finally, the angle indicator mechanism displays the relative angle between the two rubber caps. Through the cooperation of the positioning mechanism and the moving adjustment mechanism, the rubber tubes at both ends of the glass tube can be stably and accurately positioned. The detection mechanism acts directly on the positioned rubber caps, and combined with the real-time switching of the angle indicator mechanism, the accuracy of the relative angle detection of the two rubber caps is effectively improved. The structure is simple, durable, and easy to inspect and operate, making it very suitable for mass production, which can greatly improve work efficiency and reduce production costs. 2. The moving block moves along the length of the groove, which makes it easy to adjust the distance between it and the placement block, and is beneficial to adapt to the positioning requirements of glass tubes of different lengths; the second positioning block abuts against the inner side of the rubber cap, forming a lateral limit on the rubber cap, so that the position of the rubber cap remains stable; 3. When installing the detection plate, place the detection plate into the detection slot and ensure that the support column is embedded in the receiving slot. The support column provides support and positioning for the detection plate, reducing horizontal displacement of the detection plate. The detection plate provides space for the rubber cap. When the rubber cap on the detection plate is misaligned with the rubber cap on the placement block, the detection plate rotates within the receiving slot via the support column, causing the top plane of the detection plate to align with the bottom plane of the rubber cap. The rotation angle of the detection plate reflects the misalignment angle of the rubber cap in real time. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the overall structure of the non-planar internal misalignment angle measuring device of Embodiment 1 of this application; Figure 2 This is an exploded view of the non-planar internal misalignment angle measuring device of Embodiment 1 of this application; Figure 3 This is a schematic diagram of the overall structure of the non-planar internal misalignment angle measuring device of Embodiment 2 of this application.
[0024] Reference numerals: 1. Base; 2. Groove; 3. Positioning mechanism; 31. Placement block; 32. First positioning block; 4. Moving adjustment mechanism; 41. Moving block; 42. Second positioning block; 5. Detection mechanism; 51. Detection plate; 6. Angle indicating mechanism; 61. Pointer; 62. Dial; 63. Angle sensor; 7. Pressure plate; 8. Fixed pressure groove; 9. Detection groove; 10. Support column; 11. Receiving groove; 12. Controller; 13. Alarm light; 14. Support plate. Detailed Implementation
[0025] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.
[0026] Example 1: Embodiment 1 of this application discloses a non-planar internal inter-item misalignment angle measuring device, referring to... Figure 1 The system includes a base 1, on which a positioning mechanism 3 and a moving adjustment mechanism 4 are respectively provided for positioning the rubber caps at both ends. The positioning mechanism 3 and the moving adjustment mechanism 4 are arranged opposite to each other. A groove 2 is formed on the base 1 along its length direction. The positioning mechanism 3 is fixedly set at one end of the groove 2, and the moving adjustment mechanism 4 is slidably connected in the groove 2. The moving adjustment mechanism 4 is provided with a detection mechanism 5 for detecting the rotation of the rubber caps, and the moving adjustment mechanism 4 is also provided with an angle indicator mechanism 6 for displaying the rotation angle of the rubber caps.
[0027] The positioning mechanism 3 is used to position the rubber cap at one end, and the moving adjustment mechanism 4 positions the rubber cap at the other end by sliding in the groove 2. The rubber caps at both ends of the glass tube to be measured are placed on the positioning mechanism 3 and the moving adjustment mechanism 4 respectively. The detection mechanism 5 performs status detection on the two rubber caps. The angle indicating mechanism 6 displays the misalignment angle between the two rubber caps in real time according to the relative position relationship between the two rubber caps, which effectively improves the accuracy of the relative angle measurement of the two rubber caps.
[0028] Reference Figure 1 and Figure 2The positioning mechanism 3 includes a placement block 31 and a first positioning block 32. The placement block 31 is set perpendicularly to the base 1 and is located at one end of the groove 2. The bottom of the placement block 31 is fixed and locked to the bottom of the groove 2 by bolts. Both sides of the placement block 31 are pressed against the inner wall of the groove 2, effectively reducing the offset of the placement block 31. The top of the placement block 31 is the product placement surface. The first positioning block 32 is integrally formed on the top edge of the placement block 31 near the moving adjustment mechanism 4. After the rubber cap at one end of the glass tube is placed on the top of the placement block 31, the bottom of the rubber cap is in contact with the product placement surface, the inner end face of the rubber cap is in contact with the side of the first positioning block 32 away from the moving adjustment mechanism 4, and the outer diameter of the glass tube is in contact with the side of the first positioning block 32. This realizes the positioning of the rubber cap at one end of the rubber tube, effectively reducing the shaking or displacement of the rubber cap during the measurement process, and making the positioning state of one end of the glass tube stable.
[0029] Reference Figure 1 and Figure 2 The movable adjustment mechanism 4 includes a movable block 41 and a second positioning block 42. The movable block 41 is perpendicular to the base 1 and is positioned opposite to the placement block 31 in the groove 2. The bottom end of the movable block 41 is slidably connected to the groove 2, and the height of the movable block 41 is the same as the height of the placement block 31. The second positioning block 42 is integrally formed on the top edge of the movable block 41 near the placement block 31. The second positioning block 42 is positioned opposite to the first positioning block 32, and the height of the second positioning block 42 is the same as that of the first positioning block 32. The side of the second positioning block 42 away from the first positioning block 32 abuts against the inner end face of the rubber cap and the outer diameter of the glass tube, which facilitates the positioning of the rubber cap at the other end of the glass tube. By sliding the movable block 41, the distance between the second positioning block 42 and the first positioning block 32 can be flexibly adjusted to adapt to the positioning requirements of glass tubes of different lengths and improve the versatility of the equipment.
[0030] Reference Figure 1 and Figure 2 A pressure plate 7 is installed on the base 1 along its length. The pressure plate 7 is located in the groove 2. One side wall of the pressure plate 7 abuts against the inner wall of the groove 2. The top of the pressure plate 7 is fixed to the base 1 by bolts. A fixing groove 8 is opened on the bottom of the movable block 41 near the pressure plate 7. The pressure plate 7 passes through the fixing groove 8. The other side wall of the pressure plate 7 abuts against the inner wall of the fixing groove 8, and the contact surfaces of both are inclined. When the bolts are tightened to press the pressure plate 7 down and secure it, the side of the movable block 41 away from the pressure plate 7 abuts against the inner wall of the groove 2. This helps the movable block 41 and the placement block 31 to be on the same horizontal line on the base 1, thereby improving the accuracy of subsequent testing of the two rubber caps.
[0031] Reference Figure 1 and 2The top of the movable block 41 has a detection groove 9 along its length, which extends through both sides of the movable block 41. The detection mechanism 5 includes a detection plate 51. In this embodiment, the detection plate 51 is a semi-circular structure, located inside the detection groove 9, with its top abutting against the bottom of the rubber cap. Both ends of the detection plate 51 are integrally formed with support columns 10, which are symmetrically arranged. In this embodiment, the support columns 10 are semi-cylindrical structures. The top of the movable block 41 has two receiving grooves 11, which are symmetrically arranged and located on both sides of the detection groove 9. In this embodiment, the receiving grooves 11 are semi-circular groove structures. The support columns 10 are located inside the receiving grooves 11, with the radius of the receiving grooves 11 slightly larger than the radius of the support columns 10, facilitating smooth rotation of the support columns 10 within the receiving grooves 11.
[0032] The support column 10 provides stable support for the detection plate 51, so that the detection plate 51 remains horizontal or at a specific angle within the detection groove 9. After the rubber cap is positioned on the second positioning block 42, the bottom of the rubber cap contacts the top of the detection plate 51. When the rubber cap is pressed down lightly, the detection plate 51 deflects, and the plane of the detection plate 51 is completely in contact with the plane of the rubber cap. The tilt of the rubber cap can be reflected by the rotation of the detection plate 51.
[0033] Reference Figure 1 and 2 The angle indicating mechanism 6 includes a pointer 61 and a scale 62. The pointer 61 is welded and fixed to the support column 10 on the side away from the first positioning block 32. The end of the pointer 61 away from the support column 10 is bent at 90 degrees away from the base 1. The scale 62 is fixed to the side of the moving block 41 away from the placement block 31. The side of the scale 62 away from the moving block 41 is also bent at 90 degrees away from the base 1. The scale 62 is provided with scale markings. The pointer 61 is close to the scale 62. When the detection plate 51 rotates, the pointer 61 rotates with it, and the indicated value of the pointer 61 on the scale 62 can be read. This indicated value is the misalignment angle of the rubber caps at both ends.
[0034] The implementation principle of the non-planar internal misalignment angle measuring device disclosed in Embodiment 1 of this application is as follows: First, adjust the position of the moving block 41 in the groove 2 so that the distance between the outer surfaces of the first positioning block 32 and the second positioning block 42 is equal to the distance between the inner surfaces of the rubber caps at both ends of the glass tube; then, place the rubber cap at one end of the glass tube on the product placement surface on the placement block 31 so that the bottom plane of the rubber cap is completely in contact with the placement surface, and the inner end plane of the rubber cap and the outer diameter of the glass tube abut against the outer surface of the first positioning block 32; then, place the rubber cap at the other end of the glass tube on the detection plate 51. The rubber cap and the outer diameter of the glass tube are brought into contact with the two sides of the second positioning block 42. Finally, the rubber cap is gently pressed down, causing the detection plate 51 to deflect. At this time, the plane of the detection plate 51 is completely in contact with the plane of the rubber cap. The pointer 61 rotates synchronously with the detection plate 51, and the value indicated by the pointer 61 on the scale 62 can be read. This value is the misalignment angle between the rubber caps at both ends. This application effectively improves the accuracy of the relative angle detection between the rubber caps at both ends of the glass tube. It has a simple and durable structure, is easy to inspect and operate, is suitable for mass production, and can greatly improve work efficiency and reduce production costs.
[0035] Example 2: Embodiment 2 of this application discloses a non-planar internal inter-item misalignment angle measuring device, referring to... Figure 3 The difference between this embodiment and embodiment 1 is that: the angle indicating mechanism 6 includes an angle sensor 63, which is fixedly located on the side of the moving block 41 away from the placement block 31. The angle sensor 63 is connected to the detection plate 51 and is used to display the rotation angle of the detection plate 51 in real time; a support plate 14 is integrally formed on one side of the base 1, and a controller 12 and an alarm light 13 are installed on the support plate 14. The sensing part of the angle sensor 63 is connected to the controller 12, and the controller 12 is connected to the alarm light 13; when the misalignment angle displayed by the angle sensor 63 exceeds the specified angle, the controller 12 outputs a signal to the alarm light 13, and the alarm light 13 flashes to remind the operator that the misalignment angle of the rubber tubes at both ends of the glass tube exceeds the specified value.
[0036] The implementation principle of the non-planar internal misalignment angle measuring device disclosed in Embodiment 2 of this application is as follows: When the detection plate 51 deflects, the angle sensor 63 captures the rotation angle of the detection plate 51 in real time and converts the angle information into a signal output to the controller 12. If the angle value displayed by the angle sensor 63 exceeds the specified value, the controller 12 sends a trigger signal to the alarm light 13, causing the alarm light 13 to flash, so as to remind the operator that the misalignment angle of the rubber caps at both ends of the glass tube exceeds the standard.
[0037] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A device for measuring the misalignment angle between non-planar internal products, characterized in that: The device includes a base (1) with a groove (2) along its length. A positioning mechanism (3) is provided on the base (1) and is fixed at one end of the groove (2). The positioning mechanism (3) is used to position the rubber cap at one end of the glass tube. A moving adjustment mechanism (4) is provided on the base (1) and is slidably connected in the groove (2). The moving adjustment mechanism (4) is opposite to the positioning mechanism (3) and is used to position the rubber cap at the other end of the glass tube. A detection mechanism (5) is provided on the moving adjustment mechanism (4) and is used to detect the rubber cap on the moving adjustment mechanism (4). An angle indicator mechanism (6) is provided on the moving adjustment mechanism (4) and is used to display the relative angle between the two ends of the rubber tube.
2. The non-planar internal inter-item misalignment angle measuring device according to claim 1, characterized in that, The positioning mechanism (3) includes a placement block (31) and a first positioning block (32) disposed on the placement block (31). The placement block (31) is fixedly disposed at one end of the groove (2). Both sides of the placement block (31) abut against the inner wall of the groove (2). The first positioning block (32) is located on the side of the top of the placement block (31) close to the moving adjustment mechanism (4). The first positioning block (32) abuts against the inner side of the rubber cap. The top plane of the placement block (31) abuts against the bottom plane of the rubber cap.
3. The non-planar internal inter-item misalignment angle measuring device according to claim 2, characterized in that, The movable adjustment mechanism (4) includes a movable block (41) and a second positioning block (42) disposed on the movable block (41). The movable block (41) is slidably connected in the groove (2). The movable block (41) is disposed opposite to the placement block (31). The second positioning block (42) is located above the movable block (41). The second positioning block (42) is disposed opposite to the first positioning block (32). The second positioning block (42) abuts against the inner side of the rubber cap.
4. The non-planar internal misalignment angle measuring device according to claim 3, characterized in that, A pressure plate (7) is provided on the base (1) along the length direction. The pressure plate (7) is detachably fixed in the groove (2). One side wall of the pressure plate (7) abuts against the inner wall of the groove (2). A fixed pressure groove (8) is opened at the bottom of the moving block (41). The pressure plate (7) passes through the fixed pressure groove (8). The other side wall of the pressure plate (7) abuts against the inner wall of the fixed pressure groove (8). The contact surfaces of the other side wall of the pressure plate (7) and the fixed pressure groove (8) are all inclined surfaces.
5. The non-planar internal inter-item misalignment angle measuring device according to claim 3, characterized in that, The top of the movable block (41) has a detection groove (9) along its length. The detection mechanism (5) includes a detection plate (51), which is located in the detection groove (9). The detection plate (51) is used to place the rubber cap. Support columns (10) are symmetrically arranged at both ends of the detection plate (51). The top of the movable block (41) has symmetrically arranged receiving grooves (11). The two receiving grooves (11) are located on both sides of the detection groove (9), and the support columns (10) are located in the receiving grooves (11).
6. The non-planar internal misalignment angle measuring device according to claim 5, characterized in that, The angle indicating mechanism (6) includes a pointer (61) and a dial (62). The pointer (61) is located on a support column (10) on the side away from the placement block (31). The end of the pointer (61) away from the support column (10) is bent in a direction away from the base (1). The dial (62) is located on the side of the moving block (41) away from the placement block (31). The end of the dial (62) is bent in a direction away from the base (1). An angle mark is provided on the dial (62). There is a gap between the pointer (61) and the dial (62).
7. The non-planar internal misalignment angle measuring device according to claim 5, characterized in that, The angle indicating mechanism (6) includes an angle sensor (63) located on the side of the moving block (41) away from the placement block (31), and the angle sensor (63) is used to display the rotation angle of the detection plate (51).
8. The non-planar internal misalignment angle measuring device according to claim 7, characterized in that, The base (1) is equipped with a controller (12) and an alarm light (13). The controller (12) is connected to an angle sensor (63), and the alarm light (13) is connected to the controller (12). When the rotation angle of the detection plate (51) exceeds the specified value, the alarm light (13) flashes.