Length measuring device

Abstract

The utility model discloses a length measuring device which comprises a machine table, a guide rail fixedly installed on the machine table, a sliding block installed on the guide rail in a sliding mode, a distance measuring sensor fixedly installed on one side of the sliding block, and a first fixing plate fixedly connected with the machine table and arranged at the tail end of the moving path of the sliding block. The first fixing plate is provided with a baffle plate corresponding to the measuring reference surface of the distance measuring sensor, and the measuring reference surface of the baffle plate is coplanar with the contact surface of the measured object of the first fixing plate. According to the utility model, a rigid guide structure of the guide rail and the slide block is matched with the distance measuring sensor, so that measurement errors caused by deformation of a flexible tape during measurement of a traditional measuring tape are thoroughly eliminated; in combination with the coplanar design of the baffle plate and the first fixing plate, the space consistency of the contact surface of the measured object and the measurement reference surface is ensured, and systematic errors caused by reference surface offset in manual operation are solved; automatic clamping and positioning of a measured object are realized through an integrated mechanical structure, and the stability of single-person operation and the measurement efficiency are improved.

Description

Technical Field

[0001] This utility model relates to the field of length measurement technology, and in particular to a length measuring device. Background Technology

[0002] In industrial production and quality inspection, accurate measurement of product dimensions is crucial for ensuring manufacturing precision and compliance. Currently, the conventional method for measuring product length still commonly uses flexible measuring tapes, which typically consist of a rollable tape body and a hook at the end. However, due to the flexibility of the measuring tape's material, in practice, the operator must apply force with one hand to press and hold the hook at the end while continuously stretching the tape body to maintain its tautness. This operating mode has significant limitations. Especially in single-person scenarios, the operator must simultaneously manage end positioning and stretching force, which can easily lead to unexpected elastic deformation or slippage of the tape body due to uncoordinated hand movements. When the end of the measuring tape is not securely fixed, the tape can easily retract or twist during stretching, causing relative displacement between the calibrated scale and the actual measured surface, directly affecting the accuracy of the measurement data. Therefore, we provide a length measuring device to solve the above problems. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a length measuring device.

[0004] The objective of this utility model is achieved through the following technical solution:

[0005] A length measuring device includes a machine base, a guide rail fixedly mounted on the machine base, a slider slidably mounted on the guide rail, a distance sensor fixedly mounted on one side of the slider, and a first fixed plate fixedly connected to the machine base at the end of the slider's movement path. The first fixed plate is provided with a baffle corresponding to the measurement reference surface of the distance sensor, and the measurement reference surface of the baffle is coplanar with the object contact surface of the first fixed plate.

[0006] Preferably, the machine includes a frame, a table is provided on the top of the frame, and rollers are provided at the four corners of the bottom of the frame.

[0007] Preferably, at least one pressure sensor is installed on the machine base between the slider and the first fixed plate.

[0008] Preferably, a mounting plate is fixedly provided on the side of the slider away from the ranging sensor, a reference rod is fixedly installed on the mounting plate, and a scale is fixedly installed on the machine base, with the scale located directly below the reference rod.

[0009] Preferably, the reference rod includes a reading part, a limiting part is fixedly installed on the top outer peripheral surface of the reading part, and a lifting part is fixedly provided on the upper surface of the limiting part.

[0010] Preferably, the mounting plate includes a plate body fixedly connected to the slider, a slot is formed through the upper surface of the plate body, a first limiting hole is formed on the upper surface of the plate body at one end of the slot, and a second limiting hole is formed on the upper surface of the plate body at the end of the slot away from the first limiting hole.

[0011] Preferably, the depth of the first limiting hole is greater than the depth of the second limiting hole, and the first limiting hole is located directly above the scale of the ruler.

[0012] Preferably, the minimum width of the slot is L, and the diameter of the limiting part is D, satisfying that D > L.

[0013] Preferably, the slider has a positioning device, the slider has a through hole with an opening facing the first fixed plate, a slide rod is slidably disposed in the through hole, an abutment plate is fixedly installed on the outer peripheral surface of the slide rod, a transmission plate is detachably installed on the end face of the slide rod facing the first fixed plate, a spring is sleeved on the outer surface of the slide rod, one end of the spring abuts against the abutment plate, and the other end of the spring away from the abutment plate abuts against the stepped surface of the through hole, a first screwing component is screwed onto the opening of the through hole facing the first fixed plate, the first screwing component has a central hole, the central hole is slidably connected to the slide rod, a second screwing component is installed onto the opening of the through hole away from the first fixed plate, and a trigger switch is fixedly installed on the end face of the second screwing component facing the first fixed plate.

[0014] Preferably, the through hole includes a first receiving hole formed on the end face of the slider facing the first fixed plate, the first receiving hole being used to accommodate the transmission plate, a second receiving hole being formed on the inner wall of the first receiving hole away from the first fixed plate, a guide hole being formed at the end of the second receiving hole away from the first receiving hole, the second receiving hole and the guide hole forming a stepped surface, the first screwing component being screwed and installed to the opening of the second receiving hole facing the first fixed plate, and a third receiving hole being formed on the end face of the slider away from the first fixed plate, the third receiving hole being coaxially connected with the guide hole.

[0015] This utility model has the following advantages:

[0016] 1. This utility model completely eliminates measurement errors caused by the deformation of the flexible tape measure during traditional tape measure measurement by using a rigid guiding structure of the guide rail and slider in conjunction with a distance measuring sensor. The coplanar design of the baffle and the first fixed plate ensures spatial consistency between the contact surface of the measured object and the measurement reference surface, solving the systematic errors caused by reference surface offset during manual operation. The integrated mechanical structure enables automatic clamping and positioning of the measured object, simplifying traditional two-handed operation to a single-handed push-pull action, improving the stability and measurement efficiency of single-person operation. Utilizing the non-contact measurement characteristics of the distance measuring sensor, it avoids displacement of the measured object caused by uneven pressure in traditional contact measurement, making it particularly suitable for dimensional inspection of precision workpieces and fragile materials.

[0017] 2. This utility model provides a stable measuring platform through the rigid support structure of the frame and the table. Combined with the rollers set at the four corners of the bottom, it realizes convenient movement and fixation of the device, which solves the problem of difficult handling caused by the bulky size of traditional measuring equipment, and at the same time ensures the stability of the machine table during the measurement process. Attached Figure Description

[0018] Figure 1 This is a first-view structural schematic diagram of the measuring device of this utility model.

[0019] Figure 2 This is a schematic diagram of the second-view structure of the measuring device of this utility model.

[0020] Figure 3 This is a schematic diagram of the exploded state of the reference rod, mounting plate, and slider of this utility model.

[0021] Figure 4 This is a cross-sectional view of the slider of this utility model.

[0022] Figure 5 This is a schematic diagram showing the state of the reference rod of this utility model placed in the first limiting hole.

[0023] Figure 6 This is a cross-sectional view of the reference rod and mounting plate of this utility model.

[0024] In the diagram, 100 is the machine base; 110 is the machine frame; 120 is the table surface; 130 is the roller; 200 is the guide rail; 300 is the slider; 310 is the through hole; 311 is the first receiving hole; 312 is the second receiving hole; 313 is the guide hole; 314 is the third receiving hole; 320 is the slide rod; 321 is the abutment plate; 322 is the transmission plate; 330 is the first screwing component; 340 is the spring; 350 is the second screwing component; 3 60. Trigger switch; 400. Distance sensor; 500. First fixing plate; 510. Second fixing plate; 600. Baffle; 700. Reference rod; 710. Reading part; 720. Limiting part; 730. Lifting part; 800. Ruler; 900. Pressure sensor; 1000. Mounting plate; 1100. Plate body; 1200. Slot; 1300. First limiting hole; 1400. Second limiting hole. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can typically be arranged and designed in various different configurations.

[0026] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0027] like Figure 1 — Figure 6 The example shown.

[0028] A length measuring device includes a machine base 100, on which a guide rail 200 is fixedly mounted, and a slider 300 is slidably mounted on the guide rail 200. A distance sensor 400 is fixedly mounted on one side of the slider 300. A first fixing plate 500 fixedly connected to the machine base 100 is provided at the end of the slider 300's movement path. A baffle 600 corresponding to the measuring reference surface of the distance sensor 400 is provided on the first fixing plate 500. The measuring reference surface of the baffle 600 is coplanar with the object contact surface of the first fixing plate 500.

[0029] Please see Figure 1 and Figure 2 As shown, the measurement reference surface mentioned above is the side of the first fixed plate 500 facing the slider 300. It can be understood that the surface of the baffle 600 facing the distance sensor 400 is coplanar with the surface of the first fixed plate 500 facing the distance sensor 400. Furthermore, the measuring end of the distance sensor 400 is flush with the surface of the distance sensor 400 facing the first fixed plate 500. That is to say, the distance between the distance sensor 400 and the baffle 600 is the distance between the surfaces of the slider 300 and the first fixed plate 500 that are close to each other. In addition, when an object simultaneously contacts the slider 300 and the first fixed plate 500, the distance measured by the distance sensor 400 to the baffle 600 is the length of the object.

[0030] Please continue reading. Figure 1 and Figure 2 As shown, in this embodiment, when it is necessary to measure an object, the object is first placed between the slider 300 and the first fixed plate 500. Then, under the guidance of the guide rail 200, the slider 300 is pushed towards the first fixed plate 500, so that the object simultaneously contacts the slider 300 and the first fixed plate 500. At this time, the distance sensor 400 will automatically measure the distance between it and the baffle 600, and can display the measurement result on the display screen. It is understood that the machine 100 can also be equipped with corresponding computer, monitor and other components to process the data measured by the distance sensor 400 and display it on the display screen for the user to observe directly.

[0031] In this embodiment, the ranging sensor 400 can be selected as a laser rangefinder, infrared rangefinder, or other device capable of distance measurement. The specific type of the ranging sensor 400 is not limited here.

[0032] The machine platform 100 includes a frame 110, a table 120 is provided on the top of the frame 110, and rollers 130 are provided at the four corners of the bottom of the frame 110.

[0033] Please continue reading. Figure 1 and Figure 2 As shown, the guide rail 200, the first fixing plate 500, etc. are all installed on the table 120. The table 120 provides an installation platform for each component. Furthermore, the rollers 130 located at the bottom of the frame 110 can move the entire device at any time, thereby moving it to the required position and improving its practicality.

[0034] At least one pressure sensor 900 is installed on the machine base 100 between the slider 300 and the first fixed plate 500.

[0035] See Figure 1 and Figure 2As shown, in order to reduce unnecessary resource consumption, a pressure sensor 900 can be installed on the platform between the slider 300 and the first fixed plate 500. When an object is placed between the slider 300 and the first fixed plate 500, the pressure sensor 900 will detect a downward pressure signal, thereby determining that the object needs to be measured. Then, the distance sensor 400 can be automatically activated to perform the measurement, reducing the working time of the distance sensor 400 and improving its service life.

[0036] A mounting plate 1000 is fixedly installed on the side of the slider 300 away from the ranging sensor 400. A reference rod 700 is fixedly installed on the mounting plate 1000. A scale 800 is fixedly installed on the machine base 100. The scale 800 is located directly below the reference rod 700.

[0037] Please see Figure 1 , Figure 2 , Figure 3 , Figure 5 as well as Figure 6 As shown, when there is a power outage or an emergency that prevents the use of the distance sensor 400 to measure length, the object can be measured manually. Specifically, the reference rod 700 moves together with the slider 300. A scale 800 is set below the movement path of the reference rod 700. When the slider 300 moves to the predetermined position, the reference rod 700 will stop at the corresponding scale position of the scale 800. Then, the scale on the scale 800 can be read manually to achieve manual measurement.

[0038] It should be noted that, in order to ensure the accuracy of manual reading measurement, the vertical part of the reference rod 700 pointing to the scale is flush with the surface of the slider 300 facing the first fixed plate 500, so as to ensure accurate reading of the scale. In addition, the zero mark of the scale 800 should be flush with the surface of the first fixed plate 500 facing the slider 300 to facilitate the calculation of the reading.

[0039] The reference rod 700 includes a reading part 710, a limiting part 720 is fixedly installed on the top outer peripheral surface of the reading part 710, and a lifting part 730 is fixedly provided on the upper surface of the limiting part 720.

[0040] The mounting plate 1000 includes a plate body 1100 fixedly connected to the slider 300. A slot 1200 is formed through the upper surface of the plate body 1100. A first limiting hole 1300 is formed on the upper surface of the plate body 1100 at one end of the slot 1200. A second limiting hole 1400 is formed on the upper surface of the plate body 1100 at the end of the slot 1200 away from the first limiting hole 1300.

[0041] Please see Figure 3 , Figure 5 as well as Figure 6 As shown, in order to prevent the end of the reference rod 700 facing the scale 800 from contacting the surface of the scale 800 when the slider 300 moves, a slot 1200 is opened on the upper surface of the plate 1100, and a first limiting hole 1300 and a second limiting hole 1400 are opened at both ends of the slot 1200.

[0042] It should be noted that when the reading part 710 is located at the second limiting hole 1400, the bottom of the reading part 710 is suspended in the air, and at this time, the reading part 710 does not contact the surface of the scale 800. When the reading part 710 is located at the first limiting hole 1300, the bottom of the reading part 710 contacts the surface of the scale 800, thus facilitating reading at this position. In other words, when reading is performed using the distance sensor 400 or when the slider 300 is moved, the reading part 710 remains in the position of the second limiting hole 1400 and does not contact the scale 800. Similarly, when reading is not performed using the distance sensor 400 or when the slider 300 has not slid to the predetermined position, the reading part 710 remains suspended in the air. When the reading part 710 is in position 1400, it is not in contact with the scale 800. Only when the distance sensor 400 is not used for reading and the slider 300 reaches the predetermined position, the reading part 710 is moved to position 1300 by holding the lifting part 730 with the hand. Under the action of gravity, the reading part 710 slides down and then the bottom of the reading part 710 contacts the surface of the scale 800. At this time, it is only necessary to read the reading at the position of the reading part 710. That is, when manual reading is required, the operator moves the reference rod 700 from the second limit hole 1400 to the first limit hole 1300 through the lifting part 730, and the lower end of the reading part 710 contacts the scale 800 to directly read the scale value.

[0043] The depth of the first limiting hole 1300 is greater than the depth of the second limiting hole 1400, and the first limiting hole 1300 is located directly above the scale of the scale 800; the minimum width of the slot 1200 is L, and the diameter of the limiting part 720 is D, satisfying: D>L.

[0044] Please continue reading. Figure 5 and Figure 6As shown, in order to prevent the reading part 710 from entering the first limiting hole 1300 from the second limiting hole 1400 when no manual reading is required, the second limiting hole 1400 and the first limiting hole 1300 are separated and connected by the slot 1200. That is, the diameter of the first limiting hole 1300 and the second limiting hole 1400 is greater than the width of the slot 1200. Specifically, the first limiting hole 1300 and the second limiting hole 1400 are connected to the slot 1200 to form a stepped surface. This stepped surface is used to support the limiting part 720. When the reading part 710 is located at the second limiting hole 1400, the bottom surface of the limiting part 720 contacts the bottom surface of the second limiting hole 1400. The bottom surface of the second limiting hole 1400 supports the limiting part 720 to prevent the bottom of the reading part 710 from contacting the upper surface of the scale 800. When the reading part 710 is located at the first limiting hole 1300, in order to allow the bottom of the reading part 710 to contact the surface of the scale 800, the first limiting hole 1300 needs to avoid the limiting part 720. Therefore, the depth of the first limiting hole 1300 in this application is greater than the depth of the second limiting hole 1400.

[0045] Furthermore, it is understood that in order to prevent the limiting part 720 from falling down from the slot 1200, the width of the slot 1200 should be smaller than the direct diameter of the limiting part 720, so as to support the limiting part 720.

[0046] The slider 300 has a positioning device. The slider 300 has a through hole 310 opening towards the first fixed plate 500. A slide rod 320 is slidably disposed in the through hole 310. An abutment plate 321 is fixedly installed on the outer circumferential surface of the slide rod 320. A transmission plate 322 is detachably installed on the end face of the slide rod 320 facing the first fixed plate 500. A spring 340 is sleeved on the outer surface of the slide rod 320. One end of the spring 340 abuts against the abutment plate 321. The spring 340 is located away from the first fixed plate 500. One end of the abutting plate 321 abuts against the stepped surface of the through hole 310. A first screwing component 330 is screwed onto the opening of the through hole 310 facing the first fixing plate 500. The first screwing component 330 has a central hole, which is slidably connected to the slide rod 320. A second screwing component 350 is installed on the opening of the through hole 310 away from the first fixing plate 500. A trigger switch 360 is fixedly installed on the end face of the second screwing component 350 facing the first fixing plate 500.

[0047] The through hole 310 includes a first receiving hole 311 formed on the end face of the slider 300 facing the first fixing plate 500. The first receiving hole 311 is used to accommodate the transmission plate 322. A second receiving hole 312 is formed on the inner wall of the first receiving hole 311 away from the first fixing plate 500. A guide hole 313 is formed at the end of the second receiving hole 312 away from the first receiving hole 311. The second receiving hole 312 and the guide hole 313 transition to form a stepped surface. The first screwing member 330 is screwed and installed to the opening of the second receiving hole 312 facing the first fixing plate 500. A third receiving hole 314 is formed on the end face of the slider 300 away from the first fixing plate 500. The third receiving hole 314 is coaxially connected with the guide hole 313.

[0048] See Figure 4 As shown, in order to determine whether the slider 300 has moved to the tail, a corresponding positioning structure is provided on the slider 300. Specifically, when the slider 300 moves towards the first fixed plate 500, the transmission plate 322 will first touch the object. As the slider 300 continues to move, the transmission plate 322 and the slide rod 320 will overcome the elastic force of the spring 340 and continue to move to the right. The end of the slide rod 320 away from the first fixed plate 500 will abut against the trigger switch 360 to trigger it. At the same time, the transmission plate 322 enters the first receiving hole 311. After the trigger switch 360 is triggered by the slide rod 320, it can be determined that the slider 300 has moved to the predetermined position. At the same time, the distance sensor 400 will automatically measure and display the result on the display. After the measurement is completed, the slider 300 moves away from the first fixed plate 500. Under the action of the spring 340, the slide rod 322 and the transmission plate 322 will return to the initial position, that is, the transmission plate 322 will disengage from the first receiving hole 311.

[0049] It should be noted that during installation, the spring 340 can be first sleeved on the slide rod 320 and abut against the abutment plate 321. Then, the slide rod 320 extends into the guide hole 313. At this time, the first screwing member 330 passes through the slide rod 320 and is screwed into the second receiving hole 312 and abuts against the abutment plate 321, thereby limiting the abutment plate 321 and preventing the abutment plate 321 from disengaging from the second receiving hole 312. Next, the transmission plate 322 can be connected to the slide rod 320. The transmission plate 322 and the slide rod 320 can be connected by threads. Finally, the second screwing member 350, on which the trigger switch 360 is installed, is screwed into the third receiving hole 314, so that the trigger switch 360 is located in the third receiving hole 314. It can be understood that in order to enable the trigger switch 360 to transmit the signal to the outside, a hole for the signal line to pass through can be opened at the center of the second screwing member 350.

[0050] In other embodiments, the slider 300 can also be moved by a linear drive module, such as a cylinder, an electric cylinder, or a linear module. When the slider 320 touches the trigger switch 360, the linear drive module stops moving the slider 300. After the measurement is completed, the linear drive module can be controlled by a button or other element to drive the slider 300 back to its initial position. In order to be used in special conditions such as power outages, the slider 300 and the linear drive module are detachably connected. When the linear drive module is not needed to move the slider 300, the slider 300 can be separated from the drive end of the linear drive module.

[0051] It should be noted that the object being measured needs to be placed against the first fixed plate 500 during each measurement.

[0052] In this embodiment, in order to prevent the slider 300 from detaching from the end of the guide rail 200 away from the first fixing plate 500, a second fixing plate 510 is provided at the other end of the guide rail 200 to block it. Furthermore, in order to improve the measurement accuracy, the guide rail 200, the first fixing plate 500, the scale 800, the second fixing plate 510 and other components are installed on a marble platform located on the table 120.

[0053] The working process of this utility model is as follows: First, the object is placed against the surface of the first fixed plate 500 facing the slider 300. Then, the slider 300 is driven to move towards the first fixed plate 500. After it comes into contact with the object, the distance sensor 400 measures the distance between it and the baffle 600, thereby obtaining the distance between the distance sensor 400 and the baffle 600, which is the length of the object. When the distance sensor 400 is not used for measurement, the length of the object can be determined by reading the scale of the corresponding scale 800 on the reference rod 700.

[0054] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A length measuring device, characterized in that: The system includes a machine base (100), on which a guide rail (200) is fixedly installed. A slider (300) is slidably installed on the guide rail (200). A distance sensor (400) is fixedly installed on one side of the slider (300). A first fixed plate (500) is fixedly connected to the machine base (100) at the end of the slider (300)'s movement path. A baffle (600) corresponding to the measurement reference surface of the distance sensor (400) is provided on the first fixed plate (500). The measurement reference surface of the baffle (600) is coplanar with the object contact surface of the first fixed plate (500).

2. The length measuring device according to claim 1, characterized in that: The machine platform (100) includes a frame (110), a table (120) is provided on the top of the frame (110), and rollers (130) are provided at the four corners of the bottom of the frame (110).

3. The length measuring device according to claim 1, characterized in that: At least one pressure sensor (900) is installed on the machine base (100) between the slider (300) and the first fixed plate (500).

4. The length measuring device according to claim 1, characterized in that: A mounting plate (1000) is fixedly installed on the side of the slider (300) away from the distance sensor (400). A reference rod (700) is fixedly installed on the mounting plate (1000). A scale (800) is fixedly installed on the machine base (100). The scale (800) is located directly below the reference rod (700).

5. A length measuring device according to claim 4, characterized in that: The reference rod (700) includes a reading part (710), a limiting part (720) is fixedly installed on the top outer peripheral surface of the reading part (710), and a lifting part (730) is fixedly provided on the upper surface of the limiting part (720).

6. A length measuring device according to claim 5, characterized in that: The mounting plate (1000) includes a plate body (1100) fixedly connected to the slider (300). A slot (1200) is formed through the upper surface of the plate body (1100). A first limiting hole (1300) is formed on the upper surface of the plate body (1100) at one end of the slot (1200). A second limiting hole (1400) is formed on the upper surface of the plate body (1100) at the end of the slot (1200) away from the first limiting hole (1300).

7. A length measuring device according to claim 6, characterized in that: The depth of the first limiting hole (1300) is greater than the depth of the second limiting hole (1400), and the first limiting hole (1300) is located directly above the scale of the ruler (800).

8. A length measuring device according to claim 6, characterized in that: The minimum width of the slot (1200) is L, and the diameter of the limiting part (720) is D, satisfying that D > L.

9. A length measuring device according to claim 1, characterized in that: The slider (300) has a positioning device. The slider (300) has a through hole (310) opening towards the first fixed plate (500). A slide rod (320) is slidably disposed in the through hole (310). An abutment plate (321) is fixedly installed on the outer circumferential surface of the slide rod (320). A transmission plate (322) is detachably installed on the end face of the slide rod (320) facing the first fixed plate (500). A spring (340) is sleeved on the outer surface of the slide rod (320). One end of the spring (340) abuts against the abutment plate (321). One end away from the abutment plate (321) abuts against the stepped surface of the through hole (310). A first screwing member (330) is screwed onto the opening of the through hole (310) facing the first fixing plate (500). The first screwing member (330) has a central hole, which is slidably connected to the slide rod (320). A second screwing member (350) is installed on the opening of the through hole (310) away from the first fixing plate (500). A trigger switch (360) is fixedly installed on the end face of the second screwing member (350) facing the first fixing plate (500).

10. A length measuring device according to claim 9, characterized in that: The through hole (310) includes a first receiving hole (311) opened on the end face of the slider (300) facing the first fixing plate (500), the first receiving hole (311) is used to accommodate the transmission plate (322), a second receiving hole (312) is opened on the inner wall of the first receiving hole (311) away from the first fixing plate (500), a guide hole (313) is opened at the end of the second receiving hole (312) away from the first receiving hole (311), the second receiving hole (312) and the guide hole (313) transition to form a stepped surface, the first screwing member (330) is screwed and installed to the opening of the second receiving hole (312) facing the first fixing plate (500), a third receiving hole (314) is opened on the end face of the slider (300) away from the first fixing plate (500), the third receiving hole (314) is coaxially connected with the guide hole (313).

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