Length metering device

Abstract

A length metering device relates to the technical field of length metering. Comprising a first air cylinder, a piston rod at the end of the first air cylinder penetrates through the vertical frame, a fixing frame is arranged at the end of the first air cylinder, and a roller set is arranged on the inner wall of the fixing frame. When the wedge-shaped block moves to the tail portion of the pipe and automatically presses the ruler strip, the sliding rod slides on the inner wall of the column casing, the sliding rod drives the extending arm to move downwards in the vertical direction in the sliding process, and the length of the pipe is measured automatically when the pipe moves to the measuring assembly. And the pressing plate arranged at the end part of the extension arm automatically presses the ruler strip close to the tail part of the pipe and limits the ruler strip at the measuring end of the pipe, so that the influence on the measuring precision caused by edge warping generated by pressing the ruler strip by the wedge-shaped block is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of length measurement, in particular to a length measurement device. BACKGROUND

[0002] With the increasing demand for plastic pipes, accurately cutting the pipes to meet the length requirements of users has become an increasingly important indicator. In order to obtain the accurate length of the cut pipe, length measurement devices are currently used.

[0003] However, there are still some problems in actual use: 1. In the current traditional forging process of automobile parts, the existing length measurement device requires at least two workers to work together. One worker fixes one end of the tape measure, and the other worker stretches the tape measure to obtain the length information of the cut pipe, which is low in measurement efficiency. 2. During the measurement process, the stability of the tape measure is difficult to guarantee. On the one hand, the worker fixing the tape measure is prone to slight shaking due to fatigue, which causes the initial end of the tape measure to deviate from the reference line of the pipe end face. On the other hand, if the worker stretching the tape measure does not apply uniform force, the tape measure may be skewed or bent, causing positional deviation and resulting in a large error in the measurement accuracy of the angle formed between the tape measure and the pipe axis.

[0004] Chinese Patent Publication No. CN105180761A discloses a plastic pipe measurement device, which includes a driving roller and a driven roller mounted on a support. The driving roller and the driven roller are parallelly installed on the support through a bearing mounting seat. One end of the driving roller is mounted with a speed reducer driven by a motor, and the other end of the driving roller is mounted with a first sprocket. The first sprocket is connected with a second sprocket mounted on the end of the driven roller through a chain. An adjusting guide groove is provided between the first sprocket and the second sprocket, and a reset spring is fixed to a rotating shaft in the adjusting guide groove. An adjusting sprocket is mounted on the rotating shaft, and the adjusting sprocket is engaged with the chain. An encoder is mounted on the first sprocket, and the encoder is connected with a display mechanism through a wire. This patent uses the combination of the adjusting sprocket and the adjusting guide groove to measure the length of plastic pipes of different diameters. Rubber pads are provided on the rollers to prevent slipping during the measurement process.

[0005] During work, the plastic pipe is passed between the two rollers. The height of the driven roller is automatically adjusted according to the diameter of the plastic pipe. The driving roller is rotated by the motor through the speed reducer, so that the plastic pipe rotates between the two rollers. The encoder records the length of the plastic pipe according to the number of rotations of the rollers. The structure is relatively complex and is suitable for plastic pipes with regular surfaces and certain thickness. Otherwise, the plastic pipe may be deformed due to the pressure between the two rollers, affecting the measurement effect.

[0006] In view of this, we propose a length measurement device. SUMMARY

[0007] The purpose of the present application is to provide a length measurement device to solve the problems raised in the background art.

[0008] To achieve the above-mentioned purpose, the present application aims to provide a length measurement device, comprising a rack, the surface of the rack is provided with a placing table, the end of the placing table is provided with a transmission table, the upper side of the transmission table is provided with a vertical frame, the side wall of the vertical frame is provided with a display panel, the two sides of the vertical frame are provided with a limiting assembly, the limiting assembly comprises a first air cylinder, the end of the piston rod of the first air cylinder penetrates the vertical frame and is provided with a fixed frame at the end, the inner wall of the fixed frame is provided with a roller group, the roller group limits the movement of the pipe on the surface of the transmission table, so that the pipe is at the center of the transmission table, the inside of the vertical frame is provided with a measuring assembly, the length is automatically measured when the pipe moves to the measuring assembly, the bottom of the measuring assembly is provided with a positioning assembly, the positioning assembly automatically positions the tail of the pipe when the measuring assembly measures to the tail of the pipe, and real-time length information is obtained and transmitted to the display panel for display, the end of the vertical frame is provided with a impurity removal assembly, and the impurity removal assembly is used for removing impurities on the top of the pipe.

[0009] As a further improvement of the technical solution, the measuring assembly comprises a servo motor arranged at the top of the vertical frame, the output end of the servo motor is provided with a lead screw, the surface of the lead screw is provided with a moving plate, and the moving plate moves in the vertical direction on the surface of the lead screw when the lead screw rotates.

[0010] As a further improvement of the technical solution, the bottom of the moving plate is provided with a tape measure, the end of the tape measure is provided with a tape measure, and the tape measure is brought to the same level with the top of the pipe when the moving plate moves, and the tape measure extends to 5cm in a natural state.

[0011] As a further improvement of the technical solution, the end of the ruler is provided with a tooth hook, the tooth hook is perpendicular to the ruler, the end of the tooth hook is provided with a sensor, and the sensor is used for sensing the fitting state of the pipe and the tooth hook.

[0012] As a further improvement of the technical solution, the bottom of the moving plate is provided with a camera, the camera is symmetrical, and the camera obtains measurement information and transmits it to the display panel for display.

[0013] As a further improvement of the technical solution, the positioning assembly comprises a cylinder arranged at the bottom of the moving plate, a sliding rod is slidably arranged in the inner wall of the cylinder, a compression spring is arranged between the cylinder and the sliding rod, a wedge-shaped block is arranged at the end of the sliding rod, and the bottom of the wedge-shaped block is arc-shaped.

[0014] As a further improvement of the technical solution, the top of the slide rod is provided with an auxiliary rod, the auxiliary rod penetrates the moving plate and is provided with a magnetic block at the end, the moving plate is provided with an electromagnet above, and the electromagnet is powered to adsorb the magnetic block to drive the auxiliary rod to move upward in the vertical direction.

[0015] As a further improvement of the technical solution, the side wall of the cylinder is provided with a sliding groove, the end of the slide rod is provided with an extension arm, the side away from the slide rod of the extension arm is provided with a pressing plate, and the bottom of the pressing plate is provided with a toothed pattern.

[0016] As a further improvement of the technical solution, the bottom of the pressing plate is higher than the wedge block, when the pipe moves to the tail, the wedge block drives the pressing plate to move downward, when the ruler is stressed to be bent, the pressing plate presses and limits the ruler.

[0017] As a further improvement of the technical solution, the impurity removing assembly comprises a second air cylinder arranged at the end of the vertical frame, the bottom of the second air cylinder is provided with a base plate, the bottom of the base plate is provided with a hollow column, the inner wall of the hollow column is slidably provided with a moving rod, an elastic member is arranged between the hollow column and the moving rod, and the bottom of the moving rod is provided with a brush plate.

[0018] Compared with the prior art, the beneficial effects of the present application are: 1. In the length measuring device, when the pipe moves to the surface of the transmission table, the end of the ruler is provided with a tooth hook, the tooth hook is perpendicular to the ruler, the end of the tooth hook is provided with a sensor, the sensor is used for sensing the fitting state of the pipe and the tooth hook, when the end of the pipe moves to the end surface of the tooth hook, the sensor obtains the pipe information, and when the pipe moves, the tooth hook is stressed to pull the ruler to move horizontally, so that the ruler automatically measures the pipe, the labor intensity of the operator is reduced, and the measurement efficiency is improved.

[0019] 2. In the length measuring device, when the pipe moves to fit the end of the tooth hook to move, the control electromagnet is de-energized, at this time, the wedge block arranged at the bottom of the slide rod is compressed by the spring force to fit the top of the pipe to slide, the wedge block limits and straightens the ruler during the sliding process, reduces the loosening of the ruler, and affects the measurement accuracy, when the wedge block moves to the tail of the pipe to automatically press the ruler, the slide rod slides in the inner wall of the cylinder, the extension arm moves downward in the vertical direction during the sliding process of the slide rod, the pressing plate arranged at the end of the extension arm automatically presses the ruler close to the tail of the pipe, and the ruler at the measurement end of the pipe is limited, so that the wedge block is pressed to avoid the influence of the measurement accuracy caused by the edge bending of the ruler.

[0020] 3. In the length measuring device, the base plate is driven by the piston rod at the end of the second air cylinder to move downward in the vertical direction, the brush plate arranged at the bottom of the base plate fits the top of the pipe and extrudes it, when the pipe moves, the brush plate rubs the top of the pipe, so that the dust and impurities adhered to the top of the pipe fall, thereby improving the measurement accuracy. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a cross-sectional view of the overall structure of the present invention; Figure 3 This is a schematic diagram of the limiting component structure of the present invention; Figure 4 This is a schematic diagram of the measurement component structure of the present invention; Figure 5 This is a cross-sectional view of the measuring component of the present invention; Figure 6 For the present invention Figure 5 Schematic diagram at point A; Figure 7 This is a schematic diagram of the impurity removal component structure of the present invention; Figure 8 This is a front view of the overall structure of the present invention.

[0022] The meanings of the labels in the diagram are as follows: 100. Frame; 101. Placement platform; 102. Transmission platform; 103. Vertical frame; 104. Display panel; 200. First cylinder; 201. Fixed frame; 202. Roller assembly; 300. Measuring component; 301. Servo motor; 302. Lead screw; 303. Moving plate; 304. Measuring tape; 305. Ruler strip; 306. Toothed hook; 307. Sensor; 308. Camera; 400. Positioning component; 401. Column; 402. Slide rod; 403. Compression spring; 404. Wedge block; 405. Auxiliary rod; 406. Electromagnet; 407. Slide groove; 408. Extension arm; 409. Pressure plate; 500. Impurity removal component; 501. Second cylinder; 502. Base plate; 503. Hollow column; 504. Moving rod; 505. Elastic element; 506. Brush plate. Detailed Implementation

[0023] 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, and 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.

[0024] The purpose of this embodiment is to provide a length measuring device, see reference. Figures 1-8As shown, including rack 100, rack 100 surface is provided with the placement table 101, the end of the placement table 101 is provided with transmission table 102, the upper side of the transmission table 102 is provided with vertical frame 103, the side wall of the vertical frame 103 is provided with display panel 104, the two sides of the vertical frame 103 are provided with limiting assembly, the limiting assembly includes first cylinder 200, the end of the piston rod of the first cylinder 200 penetrates the vertical frame 103 and is provided with fixed frame 201 at the end, the inner wall of the fixed frame 201 is provided with roller group 202, the roller group 202 limits the pipe moving on the surface of the transmission table 102, so that the pipe is at the center of the transmission table 102, the inside of the vertical frame 103 is provided with measuring assembly 300, the length of the pipe is automatically measured when moving to the measuring assembly 300, the bottom of the measuring assembly 300 is provided with positioning assembly 400, the positioning assembly 400 automatically positions the pipe tail when the measuring assembly 300 measures to the pipe tail, and the real-time length information is transmitted to the display panel 104 for display, the end of the vertical frame 103 is provided with impurity removal assembly 500, the impurity removal assembly 500 is used for removing impurities on the top of the pipe.

[0025] When the pipe is measured, the position of the pipe is easy to deviate when moving, resulting in large measurement accuracy error, therefore, the limiting assembly includes first cylinder 200, the end of the piston rod of the first cylinder 200 penetrates the vertical frame 103 and is provided with fixed frame 201 at the end, the inner wall of the fixed frame 201 is provided with roller group 202, the roller group 202 limits the pipe moving on the surface of the transmission table 102, the measuring assembly 300 includes servo motor 301 arranged at the top of the vertical frame 103, the output end of the servo motor 301 is provided with lead screw 302, the surface of the lead screw 302 is provided with moving plate 303, the moving plate 303 moves on the surface in the vertical direction when the lead screw 302 rotates, the output end of the servo motor 301 drives the lead screw 302 to rotate, the moving plate 303 moves in the vertical direction when the lead screw 302 rotates, so that the tape measure 304 moves to be attached to the top of the pipe, thereby quickly adjusting the height of the tape measure 304 arranged at the bottom of the moving plate 303, facilitating the measurement of pipes with different diameters, the piston rod at the end of the first cylinder 200 drives the fixed frame 201 to move relatively, the roller group 202 arranged at the end of the fixed frame 201 stops moving when moving to the side wall of the pipe, so that the moving path of the pipe is horizontal when moving, thereby improving the measurement accuracy of the pipe.

[0026] When measuring the pipe, two workers are usually needed to cooperate to measure, that is, one worker fixes the measuring end, and the other worker measures the tail of the pipe by stretching the tape body, which leads to low measurement efficiency. Therefore, the measurement assembly 300 comprises a servo motor 301 arranged at the top of the stand 103. The output end of the servo motor 301 is provided with a lead screw 302. The surface of the lead screw 302 is provided with a moving plate 303. When the lead screw 302 rotates, the moving plate 303 moves in the vertical direction on the surface. The bottom of the moving plate 303 is provided with a tape 304. The end of the tape 304 is provided with a tape 304. When the moving plate 303 moves, the ruler 305 is brought into level with the top of the pipe. In the natural state, the tape 304 extends to 5 cm. When the pipe placed on the surface of the placing table 101 moves to the surface of the transmission table 102, the end of the ruler 305 is provided with a tooth hook 306. The tooth hook 306 is perpendicular to the ruler 305. The end of the tooth hook 306 is provided with a sensor 307. The sensor 307 is used to sense the fitting state of the pipe and the tooth hook 306. When the end of the pipe moves to the end face of the tooth hook 306, the sensor 307 obtains the pipe information. When the pipe moves, the tooth hook 306 is forced to pull the ruler 305 to move horizontally, so that the ruler 305 automatically measures the pipe, reduces the labor intensity of the worker, and improves the measurement efficiency.

[0027] When measuring the pipe, in order to obtain the real-time length of the pipe, the bottom of the moving plate 303 is provided with a camera 308. The camera 308 is symmetrical. The camera 308 obtains the measurement information and transmits it to the display panel 104 for display. During the automatic measurement of the pipe, the length information of the ruler 305 is obtained through the camera 308, so as to obtain the real-time length of the pipe.

[0028] In the process of measuring the pipe, it is not easy to accurately obtain the test length when the ruler 305 tests to the tail of the pipe. Therefore, the positioning assembly 400 includes a cylinder 401 arranged at the bottom of the moving plate 303. A slide rod 402 is arranged on the inner wall of the cylinder 401. A compression spring 403 is arranged between the cylinder 401 and the slide rod 402. A wedge-shaped block 404 is arranged at the end of the slide rod 402. The bottom of the wedge-shaped block 404 is arc-shaped. An auxiliary rod 405 is arranged at the top of the slide rod 402. The auxiliary rod 405 penetrates through the moving plate 303 and is provided with a magnetic block at the end. An electromagnet 406 is arranged above the moving plate 303. After the electromagnet 406 is powered on, the magnetic block is adsorbed to drive the auxiliary rod 405 to move upward in the vertical direction. When the pipe moves to fit the end of the tooth hook 306 to move, the electromagnet 406 is controlled to be powered off. At this time, the wedge-shaped block 404 arranged at the bottom of the slide rod 402 is fitted to the top of the pipe to slide under the action of the compression spring 403. The wedge-shaped block 404 limits and straightens the ruler 305 during the sliding process, reduces the influence of the loosening of the ruler 305 on the measurement accuracy, and when the wedge-shaped block 404 moves to the tail of the pipe, the magnetic force of the electromagnet 406 disappears. Therefore, the wedge-shaped block 404 is pressed against the ruler 305 under the action of the compression spring 403 to make the ruler 305 slightly bent. At the same time, the transmission table 102 is controlled to stop transmission. The image information of the bent part is obtained by the camera 308, and the length information is transmitted to the display panel 104 for viewing. The length information of the pipe can be automatically obtained by using the simple measuring instrument, thereby reducing the measurement cost. When the pipe measurement is completed, the electromagnet 406 is powered on to generate magnetism to adsorb the magnetic block arranged at the top of the auxiliary rod 405, so that the slide rod 402 drives the wedge-shaped block 404 to move upward in the reverse direction, thereby facilitating automatic measurement of the length of the subsequent pipe.

[0029] Considering that the wedge block 404 may cause the ruler strip 305 to warp on both sides during the pressing process, affecting measurement accuracy, a groove 407 is provided on the side wall of the cylinder 401, and an extension arm 408 is provided at the end of the slide rod 402. A pressure plate 409 is provided on the side of the extension arm 408 away from the slide rod 402. The bottom of the pressure plate 409 is serrated and is higher than the wedge block 404. When the tube moves to the tail, the wedge block 404 drives the pressure plate 409 to move downward. When the ruler strip 305 is bent under force, the pressure... Plate 409 presses and limits the ruler strip 305. When wedge block 404 moves to the end of the pipe and automatically presses the ruler strip 305, slide rod 402 slides on the inner wall of column cylinder 401. During the sliding process, slide rod 402 drives extension arm 408 to move down in the vertical direction. The pressure plate 409 at the end of extension arm 408 automatically presses the ruler strip 305 near the end of the pipe and limits the ruler strip 305 at the measuring end of the pipe, thereby avoiding the wedge block 404 pressing the ruler strip 305 and causing it to warp, which would affect the measurement accuracy.

[0030] Considering that when measuring pipes, if there are many impurities and foreign objects on the surface, the measurement error will be large when the ruler strip 305 is attached to the surface, therefore, the impurity removal component 500 includes a second cylinder 501 located at the end of the upright frame 103. A base plate 502 is provided at the bottom, and a hollow column 503 is provided at the bottom of the base plate 502. A moving rod 504 is slidably provided on the inner wall of the hollow column 503. An elastic element 505 is provided between the hollow column 503 and the moving rod 504. A brush plate 506 is provided at the bottom of the moving rod 504. By controlling the piston rod at the end of the second cylinder 501, the base plate 502 is driven to move downward in the vertical direction. The brush plate 506 at the bottom of the base plate 502 adheres to the top of the tube and squeezes it. When the tube moves, the brush plate 506 rubs against the top of the tube, causing dust and impurities adhering to the top of the tube to fall off, thereby improving measurement accuracy. Since the moving rod 504 at the top of the brush plate 506 slides on the inner wall of the hollow column 503, the brush plate 506 has a certain buffer when brushing the top of the tube, thereby avoiding scratches on the surface of the tube. In practical use, by controlling the piston rod at the end of the first cylinder 200 to drive the fixed frame 201 to move relative to each other, the roller group 202 provided on the inner wall of the end of the fixed frame 201 stops moving when it reaches the side wall of the pipe, so that the moving path of the pipe is horizontal. The output end of the servo motor 301 is controlled to drive the lead screw 302 to rotate. When the lead screw 302 rotates, it drives the moving plate 303 to move in the vertical direction, so that the measuring tape 304 moves to fit against the top of the pipe, thereby quickly adjusting the height of the measuring tape 304 located at the bottom of the moving plate 303, which is convenient for measuring pipes of different diameters. When the pipe moves to the surface of the transmission table 102, the end of the tape 305 is provided with a tooth hook 306 which is perpendicular to the tape 305, and the end of the tooth hook 306 is provided with a sensor 307 which is used to sense the fitting state of the pipe and the tooth hook 306; when the end of the pipe moves to the end face of the tooth hook 306, the sensor 307 obtains the pipe information; when the pipe moves, the tooth hook 306 is pulled to move the tape 305 horizontally, so that the tape 305 automatically measures the pipe, the labor intensity of the operator is reduced, and the measurement efficiency is improved. When the pipe moves to fit the end of the tooth hook 306 to move, the control electromagnet 406 is powered off; at this time, the wedge-shaped block 404 provided at the bottom of the sliding rod 402 is fitted to the top of the pipe to slide under the action of the compression spring 403; the wedge-shaped block 404 straightens the tape 305 during the sliding process, so as to reduce the loosening of the tape 305 and affect the measurement accuracy; when the wedge-shaped block 404 moves to the tail of the pipe, since the magnetic force of the electromagnet 406 disappears, the wedge-shaped block 404 at the bottom is pressed against the tape 305 under the action of the compression spring 403, so that the tape 305 is slightly bent, and the transmission of the transmission table 102 is stopped; the image information of the bent part is obtained through the camera 308, and the length information is transmitted to the display panel 104 for viewing; the length accurate information of the pipe can be automatically obtained through the simple measuring appliance of the tape 304, so as to reduce the measurement cost. When the wedge-shaped block 404 moves to the tail of the pipe to automatically press the tape 305, the sliding rod 402 slides in the inner wall of the cylinder 401, and the extension arm 408 is driven to move downward along the vertical direction during the sliding process of the sliding rod 402; the pressing plate 409 provided at the end of the extension arm 408 automatically presses the tape 305 close to the tail of the pipe, so as to limit the tape 305 at the measurement end of the pipe, thereby avoiding the bending of the tape 305 caused by the pressing of the wedge-shaped block 404 and affecting the measurement accuracy. The second cylinder 501 is controlled to drive the base plate 502 to move downward along the vertical direction, and the brush plate 506 provided at the bottom of the base plate 502 is fitted to the top of the pipe and extrudes the pipe; when the pipe moves, the brush plate 506 rubs the top of the pipe, so that the dust and impurities adhered to the top of the pipe fall off, thereby improving the measurement accuracy.

[0031] The basic principle, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application; various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A length measuring device, characterized in that: The system includes a frame (100), a placement platform (101) on the surface of the frame (100), a transmission platform (102) at the end of the placement platform (101), a vertical frame (103) above the transmission platform (102), a display panel (104) on the side wall of the vertical frame (103), and limiting components on both sides of the vertical frame (103). The limiting components include a first cylinder (200), a piston rod at the end of the first cylinder (200) passing through the vertical frame (103) and having a fixing frame (201) at the end. A roller assembly (202) is provided on the inner wall of the fixing frame (201), and the roller assembly (202) moves on the transmission platform. (102) Limit the pipe on the surface so that the pipe is in the center of the transmission table (102). The inside of the frame (103) is provided with a measuring component (300). When the pipe column (401) moves to the measuring component (300), the length is automatically measured. The bottom of the measuring component (300) is provided with a positioning component (400). When the measuring component (300) measures to the end of the pipe, the positioning component (400) automatically positions it and obtains real-time length information and transmits it to the display panel (104) for display. The end of the frame (103) is provided with a cleaning component (500). The cleaning component (500) is used to clean the top of the pipe.

2. The length measuring device according to claim 1, characterized in that: The measuring component (300) includes a servo motor (301) located on the top of the frame (103). The output end of the servo motor (301) is provided with a lead screw (302). A moving plate (303) is provided on the surface of the lead screw (302). When the lead screw (302) rotates, the moving plate (303) moves vertically on its surface.

3. The length measuring device according to claim 2, characterized in that: The bottom of the movable plate (303) is provided with a measuring tape (304), and the end of the measuring tape (304) is provided with a measuring tape (304). When the movable plate (303) moves, it drives the ruler strip (305) to be flush with the top of the pipe. In a natural state, the measuring tape (304) extends to 5cm.

4. The length measuring device according to claim 3, characterized in that: The end of the ruler strip (305) is provided with a toothed hook (306), the toothed hook (306) is perpendicular to the ruler strip (305), and the end of the toothed hook (306) is provided with a sensor (307), the sensor (307) is used to sense the fit between the pipe and the toothed hook (306).

5. The length measuring device according to claim 3, characterized in that: The bottom of the movable plate (303) is provided with a camera (308), which is symmetrical. The camera (308) acquires measurement information and transmits it to the display plate (104) for display.

6. The length measuring device according to claim 1, characterized in that: The positioning component (400) includes a cylindrical tube (401) disposed at the bottom of the movable plate (303), a sliding rod (402) slidably disposed on the inner wall of the cylindrical tube (401), a compression spring (403) disposed between the cylindrical tube (401) and the sliding rod (402), and a wedge block (404) disposed at the end of the sliding rod (402), the bottom of the wedge block (404) being arc-shaped.

7. The length measuring device according to claim 6, characterized in that: The top of the slide bar (402) is provided with an auxiliary rod (405), the auxiliary rod (405) passes through the moving plate (303) and has a magnetic block at its end. An electromagnet (406) is provided above the moving plate (303). When the electromagnet (406) is energized, it attracts the magnetic block and drives the auxiliary rod (405) to move vertically.

8. The length measuring device according to claim 6, characterized in that: The column (401) has a sliding groove (407) on its side wall, and the end of the slide rod (402) has an extension arm (408). The side of the extension arm (408) away from the slide rod (402) has a pressure plate (409), and the bottom of the pressure plate (409) is toothed.

9. The length measuring device according to claim 8, characterized in that: The bottom of the pressure plate (409) is higher than the wedge block (404). When the pipe moves to the tail, the wedge block (404) drives the pressure plate (409) to move down. When the ruler (305) is bent under force, the pressure plate (409) presses and limits the ruler (305).

10. The length measuring device according to claim 1, characterized in that: The impurity removal component (500) includes a second cylinder (501) located at the end of the frame (103). The bottom of the second cylinder (501) is provided with a base plate (502). The bottom of the base plate (502) is provided with a hollow column (503). A moving rod (504) is slidably provided on the inner wall of the hollow column (503). An elastic element (505) is provided between the hollow column (503) and the moving rod (504). A brush plate (506) is provided at the bottom of the moving rod (504).

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