A diameter measuring device

Abstract

The utility model provides a diameter measuring device relates to measuring tool technical field, and the basic scale is equipped with the axial sliding slot along the length direction, first end card setting is in the front side of basic scale, vernier and the axial sliding slot of basic scale slide fit, the measuring end of vernier is equipped with second end card, and second end card is opposite setting with first end card, and the opposite area of first end card and second end card is diameter measurement area, diameter positioning ruler includes first vice ruler and second vice ruler, and the first end of first vice ruler is connected on the back side of basic scale, and the first end of second vice ruler is slidably connected with the axial sliding slot of basic scale, and the projection area of diameter measurement area along the direction from the front side to the back side is measurement projection area, and the second end of first vice ruler and second vice ruler is hinged, and the area of the surface of first vice ruler and second vice ruler and measurement projection area intersection is work piece abutting portion, can efficiently and safely measure the diameter of the inverted hammer, can position the center of circle fast.

Description

Technical Field

[0001] This utility model relates to the field of measuring tool technology, specifically to a diameter measuring device. Background Technology

[0002] In the segregation production process, the tamping hammer is a key piece of equipment, and its diameter directly affects the uniformity of material segregation and production quality. Therefore, it is necessary to accurately measure the diameter of the tamping hammer regularly. Currently, the industry commonly uses a traditional measuring tape as the measuring tool. The operation method is as follows: the worker holds the measuring tape, hooks the hook at the end of the tape to the edge of the circular end face of the tamping hammer, stretches the tape to the other end, and then reads the value. However, this measurement method has the following significant drawbacks:

[0003] Significant safety hazards:

[0004] During the segregation production process, the tamping hammer is constantly exposed to high temperatures (surface temperatures can reach hundreds of degrees Celsius). Workers cannot get close to the measuring area and must operate the measuring tape from a distance. This remote operation not only makes it difficult to stably control the stretching direction of the measuring tape, but also poses a serious risk of burns if the operator makes a mistake and brings their hands close to the hot surface.

[0005] Low measurement accuracy:

[0006] Because close observation is not possible, the contact point between the measuring tape hook and the edge of the tamping hammer is prone to misalignment, and the stretching direction of the measuring tape is difficult to perfectly align with the diameter of the tamping hammer (easily resulting in a skew angle), leading to a significant deviation between the measured value and the actual diameter. Furthermore, in high-temperature environments, workers' visual judgment is easily affected by heat waves, further exacerbating reading errors and making it difficult to meet the accuracy requirements of production.

[0007] Locating the center of the circle is difficult and inefficient.

[0008] The circular end face of the tamping hammer has a columnar structure, and its center position is not clearly marked. When measuring with a measuring tape, the hook position must be adjusted multiple times to find the diameter direction, which is cumbersome. For batch measurement scenarios (such as regular inspection of multiple machines on a production line), each measurement requires a long time to locate the center and record the reading, resulting in low overall efficiency and seriously affecting the production rhythm.

[0009] In summary, existing methods for measuring the diameter of tamping hammers based on measuring tapes have insurmountable shortcomings in terms of safety, accuracy, efficiency, and data management. There is an urgent need for a dedicated measuring device that can adapt to high-temperature environments, achieve accurate long-distance measurement, quickly locate the center of the circle, and automatically record data to meet the actual needs of segregation production. Utility Model Content

[0010] The purpose of this invention is to provide a diameter measuring device to solve the problems existing in the prior art, which can efficiently and safely measure the diameter of the inverted hammer and quickly locate the center of the circle.

[0011] To achieve the above objectives, this utility model provides the following solution: a diameter measuring device, comprising:

[0012] A basic scale, wherein the basic scale is provided with an axial groove along its length;

[0013] The first end clip is disposed on the front side of the base scale.

[0014] A vernier scale, wherein the vernier scale is slidably fitted with the axial groove of the base scale; the measuring end of the vernier scale is provided with a second end clip, the second end clip being disposed opposite to the first end clip, and the area where the first end clip and the second end clip are opposite is the diameter measuring area;

[0015] A diameter positioning ruler, comprising a first auxiliary ruler and a second auxiliary ruler, wherein a first end of the first auxiliary ruler is connected to the back side of the base ruler; a first end of the second auxiliary ruler is slidably connected to the axial groove of the base ruler; and the diameter measuring area is a measurement projection area along the projection area from the front side to the back side.

[0016] The second ends of the first and second auxiliary rulers are hinged together; the area where the surfaces of the first and second auxiliary rulers intersect with the measurement projection area is the workpiece contact area.

[0017] In one embodiment, the first auxiliary ruler includes a first inner sidewall and a first outer sidewall, the first inner sidewall and the first outer sidewall being arranged parallel to each other; the second auxiliary ruler includes a second inner sidewall and a second outer sidewall, the second inner sidewall and the second outer sidewall being arranged parallel to each other; the intersection of the first inner sidewall and the second inner sidewall is the inner intersection point, and the intersection of the first outer sidewall and the second outer sidewall is the outer intersection point.

[0018] As one embodiment, the vernier scale is provided with a display for displaying measurement data, and the display is fixedly mounted on the vernier scale by a clamp.

[0019] As one embodiment, the vernier scale is provided with a handle, which is located at the end of the vernier scale away from the second end clip, and the display is located on the vernier scale in the middle section between the second end clip and the handle.

[0020] As one embodiment, the vernier scale is provided with a first slider, which slides in cooperation with the axial groove.

[0021] In one embodiment, the vernier scale is slidably engaged with the axial groove via two first sliders; one of the first sliders is integrated on the vernier scale, and the other first slider is disposed on the second end clip; the two first sliders are distributed at intervals along the axial direction of the base scale, and either first slider is slidably engaged with the side wall of the axial groove.

[0022] In one embodiment, the first end of the first auxiliary ruler is rotatably connected to the base ruler via a pivot; the first end of the first auxiliary ruler has a first shaft hole; the pivot includes an insert section and a fixing section, the diameter of the insert section is adapted to the first shaft hole and is inserted into the first shaft hole, and the fixing section is inserted into a preset mounting hole of the base ruler.

[0023] In one embodiment, the first end of the second scale is provided with a second shaft hole, one end of the second slider is embedded in the second shaft hole, and the other end of the second slider extends into the axial groove of the base scale and slides in cooperation with the axial groove.

[0024] As one embodiment, the second end of the first auxiliary ruler and the second end of the second auxiliary ruler are both provided with hinge holes, and the axes of the two hinge holes coincide; the pin passes through the two hinge holes.

[0025] In one embodiment, the first end clip is fixedly disposed at the end of the base scale, and the first end clip is perpendicular to the length direction of the base scale; the second end clip is parallel to and opposite to the first end clip.

[0026] The present invention achieves the following technical advantages over the prior art:

[0027] 1. This utility model solves safety hazards through a spatial structure design of "front measurement + back positioning": the first end clip and the second end clip on the front side of the basic ruler are set separately from the diameter positioning ruler (first auxiliary ruler and second auxiliary ruler) on the back side. The operator can control the end clips to clamp on the front side through the vernier ruler, and the auxiliary ruler on the back side automatically abuts against the workpiece. There is no need to contact the high temperature hammer at close range, which avoids the risk of burns from the structure and can efficiently measure the diameter of the hammer.

[0028] This invention achieves precise positioning through dual geometric constraints: the first and second auxiliary rulers of the diameter positioning ruler unfold to form a 90° angle, and the workpiece contact point and the perpendicular intersection point form a "three-point concircle". Based on the principle that "a 90° circumferential angle corresponds to the diameter", the line connecting the contact points is ensured to be the actual diameter, eliminating the skew error of the measuring tape. At the same time, the midpoint of the line connecting the two contact points is the center of the circle, allowing for quick positioning without manual adjustment. Combined with the vernier caliper and the basic caliper, the diameter of the tamping hammer can be measured efficiently, significantly improving the efficiency of batch measurement and solving the problems of difficulty in finding the center and cumbersome data recording.

[0029] Other technical solutions of this utility model have also achieved the following technical effects:

[0030] 2. By adjusting the display settings, the problem of errors easily caused by manual reading in traditional vernier calipers is solved. It enables automated acquisition, real-time display, and recording of measurement data, making it particularly suitable for batch measurement scenarios (such as the quality inspection stage of a tamping hammer production line), significantly improving measurement efficiency and data accuracy. The measurement process can be completed without additional operations, simplifying the operation steps. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0033] Figure 2 for Figure 1 A magnified view of a section at point A in the middle;

[0034] Figure 3 for Figure 1 A magnified view of a section at point B in the middle;

[0035] Figure 4 This is a schematic diagram of the overall structure of this utility model from another perspective;

[0036] Figure 5 for Figure 4 A magnified view of a section at point C;

[0037] Figure 6 for Figure 4 A magnified view of a section at point D;

[0038] Figure 7 This is a schematic diagram of the assembly of the vernier scale and the basic scale of this utility model;

[0039] Figure 8 This is a schematic diagram of the assembly structure of the vernier scale and the basic scale of this utility model from another perspective;

[0040] Figure 9 for Figure 8 A magnified view of a section at point E in the middle.

[0041] The components include: 1. Basic scale; 2. First end clip; 3. Vernier scale; 4. Axial groove; 5. Second end clip; 6. First auxiliary scale; 7. Second auxiliary scale; 8. First inner sidewall; 9. First outer sidewall; 10. Second inner sidewall; 11. Second outer sidewall; 12. Inner intersection point; 13. Outer intersection point; 14. Display; 15. Clamp; 16. Handle; 17. First slider; 18. First shaft hole; 19. Second shaft hole; 20. Hinge hole. Detailed Implementation

[0042] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0043] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] This embodiment provides a diameter measuring device; please refer to [reference needed]. Figure 1-9As shown, the system includes a base scale 1, a first end clip 2, a vernier caliper 3, and a diameter positioning scale. The first end clip 2 is mounted on the base scale 1, preferably on its front side. The base scale 1 has an axial groove 4 along its length, which extends through the base scale 1 along the line connecting its front and rear sides. The first end clip 2 is mounted on the front side of the base scale 1, preferably at its end. The vernier caliper 3 slides within the axial groove 4 of the base scale 1 and is also located on the front side of the base scale 1. The axis of the vernier caliper 3 is parallel to the axis of the base scale 1. A second end clip 5 is mounted at the measuring end of the vernier caliper 3, opposite to the first end clip 2. The first end clip 2 and the second end clip 5 are axially aligned, and the area opposite the first end clip 2 and the second end clip 5 is the diameter measurement area. The diameter positioning ruler includes a first auxiliary ruler 6 and a second auxiliary ruler 7. The second ends of the first auxiliary ruler 6 and the second auxiliary ruler 7 are hinged together by a hinge shaft, and the included angle between the first auxiliary ruler 6 and the second auxiliary ruler 7 is 90°. The first end of the first auxiliary ruler 6 is connected to the side of the base ruler 1 opposite to the first end clip 2, that is, both the first auxiliary ruler 6 and the second auxiliary ruler 7 are located on the back side of the base ruler 1. The first end of the second auxiliary ruler 7 is slidably connected to the axial groove 4 on the base ruler 1. The diameter measuring area is the projection area along the direction from the front side of the base ruler 1 to the back side (the thickness direction of the base ruler 1). Both the first auxiliary ruler 6 and the second auxiliary ruler 7 are provided with workpiece abutment parts, which directly abut the workpiece to be measured. The surface of the first auxiliary ruler 6 and the second auxiliary ruler 7 that intersects with the measurement projection area is the workpiece abutment part. Both the base ruler 1 and the vernier caliper 3 are provided with dimensional data.

[0045] The workpiece abutment portion of the first ruler 6 and the workpiece abutment portion of the second ruler 7 can be specifically defined by the following methods:

[0046] Diameter measurement zone: This refers to the axial space between the first end clamp 2 and the second end clamp 5 when they are set opposite each other along the axial direction (length direction) of the base scale 1. The centerline of this zone is collinear with the axis of the base scale 1 and serves as the theoretical reference direction for measuring the diameter of the workpiece.

[0047] Measurement projection area: The thickness direction of the base scale 1 is the direction of the distance between the "front side" and the "back side" of the base scale 1 (the direction of the line connecting them), and it is perpendicular to the axial direction. The cylindrical space area formed by the projection of the diameter measurement area along the thickness direction of the base scale 1 (on the side where the first auxiliary scale 6 and the second auxiliary scale 7 are located) is called the measurement projection area.

[0048] Based on this, regarding the workpiece abutment portion of the first scale 6: the area on the surface of the first scale 6 that intersects with the measurement projection area is the workpiece abutment portion of the first scale 6. Since the measurement projection area is projected from the diameter measurement area on the front side, this intersecting area must be aligned with the axial centerline of the diameter measurement area on the front side.

[0049] Regarding the workpiece contact portion of the second scale 7: The area on the surface of the second scale 7 that intersects with the measurement projection area is the workpiece contact portion of the second scale 7.

[0050] The vernier caliper 3 measures the distance between the first end clip 2 and the second end clip 5 on the front side. This distance is determined by the spatial relationship of the projection area. Since the thickness of the base scale 1 is relatively small, the distance between the first end clip 2 and the second end clip 5 can be directly equivalent to the distance between the workpiece contact portions of the first auxiliary scale 6 and the second auxiliary scale 7 on the back side of the base scale 1, ultimately reflecting the diameter of the workpiece being measured. Furthermore, the accuracy of the diameter measurement can be ensured by: aligning the first end clip 2 along the thickness direction of the base scale 1 with the workpiece contact portion of the first auxiliary scale 6; and aligning the second end clip 5 along the thickness direction of the base scale 1 with the workpiece contact portion of the second auxiliary scale 7.

[0051] Working principle:

[0052] S1. Initial state preparation: The first auxiliary ruler 6 and the second auxiliary ruler 7 are extended to 90° through the hinge shaft and maintained at this angle; the first end clip 2 and the second end clip 5 on the vernier scale 3 are axially aligned and set relative to each other to ensure that the measurement baseline is consistent.

[0053] S2. Positioning of the workpiece to be measured: Move the measuring device to position the workpiece to be measured (such as a tamping hammer or other workpiece with a circular end face) at the measuring station; make one edge of the circular end face of the workpiece in stable contact with the working surface of the first end clamp 2 to achieve preliminary axial positioning (at this time, the edge of the workpiece is located within the diameter measuring area).

[0054] S3, Diameter positioning ruler contact adjustment

[0055] Slide the second scale 7. The second scale 7 slides along the axial groove 4 of the base scale 1. The first end (back side slider) of the second scale 7 drives the entire diameter positioning scale to approach the workpiece being measured. Adjust the position of the first scale 6 and the second scale 7 so that the workpiece contact part (the area intersecting with the measurement projection area) of the two is in contact with the edge of the circular end face of the workpiece being measured.

[0056] Ensure that the workpiece contact part (A) of the first ruler 6, the workpiece contact part (B) of the second ruler 7, and the workpiece contact part (A) and workpiece contact part (B) intersect perpendicularly at the point (O) along the extension lines of their respective side walls. These three points (A, B, O) form a "three-point concircle" (all three points are on the circular end face of the workpiece), and ∠AOB = 90°. At this time, the line connecting A and B is the diameter of the circular end face of the workpiece (which conforms to the theorem that "90° circumferential angle corresponds to diameter"). The midpoint of the line connecting A and B is the center point, thus achieving rapid positioning of the center.

[0057] S4. Vernier scale and second end clamp positioning: Slide the vernier scale 3 along the axial groove 4 of the base scale 1, driving the second end clamp 5 to move towards the workpiece being measured; align the second end clamp 5 with the workpiece contact part (B) of the second auxiliary scale 7; the first end clamp 2 can be aligned with the workpiece contact part (A) of the first auxiliary scale 6. Preferably, the working surface of the second end clamp 5 can also stably contact the other edge of the circular end face of the workpiece being measured, and the second end clamp 5 and the first end clamp 2 together clamp the workpiece, with the contact point located within the diameter measurement area;

[0058] At this time, the line connecting the first end card 2 and the second end card 5 on the front side, and the line connecting A and B on the back side, can be equivalent to the diameter of the workpiece to be measured. Preferably, the first end card 2 and the workpiece contact part (A) are aligned along the thickness direction of the base scale 1, and the second end card 5 and the workpiece contact part (B) are aligned along the thickness direction of the base scale 1.

[0059] S5. Diameter value reading:

[0060] After the first end clip 2, the second end clip 5, and the workpiece abutment part (A) and the workpiece abutment part (B) have all made stable contact with the workpiece being measured, read the scale value of the vernier scale 3 relative to the base scale 1. This value is the diameter value of the circular end face of the workpiece being measured (the outer diameter when measuring the outer circle, and the inner diameter when measuring the inner circle).

[0061] S6, Reset Operation

[0062] Loosen the hinge shaft locking piece and fold the first scale 6 and the second scale 7 into a close-fitting state (to reduce the space occupied on the back side); slide the vernier scale 3 to the initial position away from the first end clip 2 to prepare for the next measurement.

[0063] This invention utilizes the spatial coordination of "front end card measurement + back side auxiliary ruler positioning" to ensure that the front and rear references are collinear by using the measurement projection area, and forms a geometric constraint by combining the 90° included angle of the diameter positioning ruler, ultimately achieving accurate diameter measurement.

[0064] Preferably, in step S1, the vernier scale 3 first slides along the axial groove 4 of the base scale 1 to a preset position away from the first end clip 2, so that the slider of the vernier scale 3 and the slider of the second scale 7 form a gap in the axial groove 4; to avoid interference between the slider of the second scale 7 and the slider of the vernier scale 3 when the slider of the second scale 7 slides in the axial groove 4, and to ensure the smooth unfolding of the second scale 7.

[0065] In steps S3 and S4:

[0066] Front contact point: Located within the diameter measurement area (along the axial centerline), the contact point between the first end clip 2 and the second end clip 5 and the workpiece is the front contact point, directly contacting the workpiece to be measured; the front contact point is located on the front side of the base scale 1 and is collinear along the axial direction;

[0067] Back contact point: The workpiece abutment part of the first scale 6 is set on (A) one side wall of the first scale 6, which is the first abutment part side wall. The workpiece abutment part (B) of the second scale 7 is set on one side wall of the second scale 7, which is the second abutment part side wall. The contact point between the workpiece abutment part of the first abutment part side wall and the second abutment part side wall and the workpiece being measured is the back contact point; located on the back side of the base scale.

[0068] Perpendicular intersection point: The angle between the first and second abutment sidewalls is 90°, and the point where these two sidewalls meet is the perpendicular intersection point (O), which is a geometrically defined "L-shaped vertex". The perpendicular intersection point (O) of the first and second abutment sidewalls, and the workpiece abutment parts (A, B) on the first and second scales 6 and 7 form three points concyclic in space, satisfying the geometric theorem that "a 90° circumferential angle corresponds to a diameter". Alternatively, the perpendicular intersection point can also be the perpendicular intersection point formed in space by the extensions of the first and second abutment sidewalls, i.e., a virtual intersection point (not a physical contact point). All three points (A, B, O) are located on the circle containing the circular end face of the workpiece being measured; ∠AOB = 90° (guaranteed by the 90° angle between the two abutment sidewalls). According to the geometric theorem of circles, "the chord subtended by a 90° circumferential angle is a diameter", the line connecting the back contact points A and B (AB) must be the diameter of this circle.

[0069] In this device, when the workpiece contact portions of the first scale 6 and the second scale 7 respectively contact the circular end face of the workpiece being measured, the line connecting the two contact points (points A and B) is the diameter of the circular end face (based on the geometric theorem that "a 90° circumferential angle corresponds to a diameter"). Since the midpoint of the diameter is necessarily the center of the circular end face, the midpoint of the line connecting points A and B is the center point of the circular end face of the workpiece being measured. In this invention, point A is the contact point between the workpiece contact portion of the first scale 6 and the workpiece being measured, and point B is the contact point between the workpiece contact portion of the second scale 7 and the workpiece being measured. The line connecting points A and B is the diameter of the workpiece being measured, and the midpoint of the diameter is the unique center of the circle. Therefore, the midpoint of the line connecting points A and B completely coincides with the center of the circular end face of the workpiece being measured, and the center position can be determined without additional measurement.

[0070] In one embodiment, a midpoint scale mark can be marked on the vernier scale 3 or the base scale 1, and this mark is aligned with the midpoint of the distance between the first end clip 2 and the second end clip 5. When points A and B are in stable contact with the workpiece, the operator can visually align the midpoint scale mark with the workpiece surface and directly mark the center position without the need for additional tools (such as compasses or rulers).

[0071] Compared to traditional methods for locating the center of a circle (such as finding the center by drawing intersecting arcs through multiple measurements), this invention utilizes the geometric inevitability that "the midpoint of the diameter is the center of the circle," simultaneously locating the center of the circle while measuring the diameter, without requiring additional steps, achieving "one operation to obtain both the diameter and the center of the circle." With the assistance of midpoint scale markings, operators can quickly mark the center of the circle with high accuracy, solving the problem of "cumbersome steps and long time consumption" in traditional methods.

[0072] In one embodiment, both the first auxiliary ruler 6 and the second auxiliary ruler 7 are rectangular rod-shaped structures; the first auxiliary ruler 6 includes a first inner sidewall 8 and a first outer sidewall 9, which are arranged in parallel; the second auxiliary ruler 7 includes a second inner sidewall 10 and a second outer sidewall 11; when the first auxiliary ruler 6 and the second auxiliary ruler 7 are unfolded at right angles, the vertical intersection of the first inner sidewall 8 and the first outer sidewall 9 is the inner intersection point 12, and the vertical intersection of the first outer sidewall 9 and the second outer sidewall 11 is the outer intersection point 13.

[0073] This can be divided into two application scenarios:

[0074] Scenario 1: Measurement of an outer cylindrical workpiece (tamping hammer):

[0075] The first inner sidewall 8 (first abutting part sidewall) and the second inner sidewall 10 (second abutting part sidewall) are arranged opposite each other, and the angle between the first inner sidewall 8 and the second inner sidewall 10 is 90°. The workpiece abutting part A (on the first inner sidewall 8), the workpiece abutting part B (on the second inner sidewall 10) and the vertical intersection point O (inner intersection point 12) are concircular on the outer circumference of the tamping hammer.

[0076] Geometric conclusion: AB is the outer diameter, the line connecting the front contact points is collinear with the axial direction of AB, and the end-clamp distance measured by vernier caliper 3 is equal to the length of AB (i.e., the outer diameter).

[0077] Scenario 2: Measurement of inner cylindrical workpieces (cylinders)

[0078] Structural fit: The first outer wall 9 (first abutment side wall) and the second outer wall 11 (second abutment side wall) are set back from each other with an included angle of 90°. The workpiece abutment A (on the first outer wall 9), the workpiece abutment B (on the second outer wall 11), and the vertical intersection point O (intersection point 13) are concircular on the inner circumference of the cylinder.

[0079] Geometric conclusion: AB is the inner diameter (inner diameter), the line connecting the front contact points is collinear with the axial direction of AB, and the end-clamp distance measured by vernier caliper 3 is equal to the length of AB (i.e., the inner diameter).

[0080] In one embodiment, the 90° angle between the sidewall of the first abutment portion and the sidewall of the second abutment portion is kept fixed by a rigid structure or angle locking component, such as a locking nut at the end of the hinge shaft, to ensure that the angle remains unchanged during the measurement process and to avoid diameter positioning errors due to angle deviation.

[0081] In one embodiment, a display 14 is provided on the vernier scale 3. When the second end clip 5 is engaged with the other end of the tamping hammer bottom surface, data is recorded and the measurement data is displayed through the display 14. Preferably, the display 14 is fitted onto the vernier scale 3 through a clamp 15, and the vernier scale 3 is electrically connected to the displacement sensor (such as an optical grating sensor or a magnetic grating sensor) of the vernier scale 3 through a built-in data transmission module (such as a wire or a wireless communication unit).

[0082] When the vernier scale 3 slides along the axial groove 4, making the second end clamp 5 stably contact the other edge of the workpiece being measured (such as the circular end face of a tamping hammer) (i.e., the second end clamp 5 and the first end clamp 2 together hold the workpiece, forming an effective measurement state), the displacement sensor of the vernier scale 3 collects the displacement data of the vernier scale 3 relative to the base scale 1 in real time, and transmits the data to the processing unit of the display 14. The processing unit converts the displacement data into the diameter value of the workpiece being measured (combined with the reference scale of the base scale 1), and displays the measured value (the unit can be preset to millimeters) on the screen of the display 14 in real time.

[0083] In one embodiment, a handle 16 is integrated onto the vernier scale 3. The handle 16 is located at the end of the vernier scale 3 away from the second end clip 5 (i.e., the operating end of the vernier scale 3). The handle 16 and the vernier scale 3 can be integrally formed or fixed by bolts. The handle 16 is designed with an ergonomic arc-shaped grip (the surface may have anti-slip texture or a rubber sleeve) to facilitate one-handed operation. The display 14 is fixed to the vernier scale 3 by a clamp 15 and is located in the middle section between the second end clip 5 and the handle 16. The screen of the display 14 faces the same direction as the scale surface of the base scale 1 (i.e., towards the operator's viewing angle) and maintains a preset distance from the handle 16 to ensure that when the operator holds the handle 16, their line of sight can naturally fall on the screen, avoiding obstruction of the displayed content by their hand.

[0084] When the operator holds the handle 16 and pushes the vernier scale 3 along the axial direction of the base scale 1, the vernier scale 3 slides smoothly back and forth ("back and forth" refers to the length direction along the base scale 1) through the cooperation of the bottom slider and the axial groove 4, until the second end clip 5 makes stable contact with the other edge of the workpiece being measured (such as the circular end face of a tamping hammer). At this time, the pushing force of the handle 16 is transmitted to the second end clip 5 through the rigid structure of the vernier scale 3, ensuring uniform contact pressure.

[0085] In one embodiment, the vernier scale 3 slides with the axial groove 4 via a first slider 17, and a first slider 17 is also provided on the second end clip 5 to achieve a stable sliding engagement between the vernier scale 3 and the base scale 1. Preferably, the vernier scale 3 specifically slides with the axial groove 4 of the base scale 1 via two first sliders 17; one first slider 17 is integrated into the bottom of the vernier scale 3 (on the side near the handle 16), and the other first slider 17 is provided at the bottom of the second end clip 5; the two first sliders 17 are distributed at intervals along the axial direction of the base scale 1, and both are adapted to the inner sidewall of the axial groove 4 (e.g., using a T-shaped slider and a T-shaped groove to engage), ensuring guiding accuracy during sliding.

[0086] In one embodiment, the first end of the first auxiliary scale 6 is rotatably connected to the base scale 1 via a rotating shaft. Specifically, a circular first shaft hole 18 is formed at the first end of the first auxiliary scale 6 (the end closest to the base scale 1). The inner diameter of the shaft hole and the outer diameter of the rotating shaft are clearance-fitted to ensure that the rotating shaft can rotate flexibly within the shaft hole while avoiding wobbling caused by excessive clearance. The rotating shaft is preferably stepped, including an insert section (the diameter of which matches the first shaft hole 18) and a fixed section (the diameter of which is slightly larger than the insert section). One end of the insert section is inserted into the first shaft hole 18, and the fixed section is fixed in a preset mounting hole of the base scale 1 by an interference fit or a threaded connection, ensuring that the rotating shaft and the base scale 1 are relatively stationary.

[0087] Preferably, the end of the embedded section of the rotating shaft is provided with an annular shoulder, the diameter of which is larger than the inner diameter of the first shaft hole 18. After the rotating shaft is embedded in the first shaft hole 18, the shoulder fits against the side of the first auxiliary ruler 6, preventing the first auxiliary ruler 6 from falling off the rotating shaft during rotation.

[0088] When the first scale 6 rotates around the pivot, its second end (the hinged end with the second scale 7) drives the second scale 7 to move synchronously. In conjunction with the sliding engagement of the second scale 7 with the second slider and the axial groove 4, the two scales can smoothly switch from folding and storage to unfolding at a right angle. When folded, the first scale 6 and the second scale 7 are parallel and attached to the back side of the base scale 1, which greatly reduces the overall volume of the device. When unfolded, the rotation center of the pivot and the hinge axis center of the two scales form a stable "double fulcrum structure", which ensures that the positioning is firm after unfolding at a 90° angle and avoids errors caused by shaking during measurement.

[0089] In one embodiment, the first end of the second auxiliary ruler 7 is slidably engaged with the axial groove 4 of the base ruler 1 via the second slider. A circular second shaft hole 19 is opened at the first end of the second auxiliary ruler 7 (the end closer to the base ruler 1). The inner diameter of the second shaft hole 19 is slightly larger than the outer diameter of the second slider to ensure that the second slider can rotate flexibly. The second slider is cylindrical in shape, with one end embedded in the second shaft hole 19 and the other end (the protruding end) extending into the axial groove 4 of the base ruler 1, forming a sliding engagement with the side wall of the axial groove 4.

[0090] Preferably, the embedded end of the second slider is provided with an annular shoulder, the diameter of which is larger than the inner diameter of the second shaft hole 19. After being embedded, it is fixed to the end of the second shaft hole 19 to prevent the second slider from falling out of the second shaft hole 19 during sliding or rotation. The second slider adopts a cylindrical structure and is rotatably connected to the second shaft hole 19. Its core function is to realize the separation of the "sliding degree of freedom" and the "rotational degree of freedom". The sliding degree of freedom along the axial groove 4 ensures that the second scale 7 can approach or move away from the workpiece being measured and adjust the contact position. The rotational degree of freedom around its own axis adapts to the 90° angle unfolding action of the first scale 6 and the second scale 7, avoiding structural interference caused by rigid connection (such as friction and jamming between the end of the scale and the side wall of the groove when unfolding).

[0091] Since the second scale 7 and the vernier scale 3 are respectively connected to the same axial groove 4 through the second slider and the first slider 17 (the two are located on the back side and the front side of the base scale 1 respectively), the sliding directions of the second slider and the first slider 17 are parallel; the sliding stroke of the second slider in the axial groove 4 is adapted to the stroke of the first slider 17, ensuring that the movement range of the second scale 7 and the vernier scale 3 covers the measurement requirements of the workpiece being measured.

[0092] In one embodiment, the second ends (the ends furthest from the base scale 1) of the first auxiliary scale 6 and the second auxiliary scale 7 are hinged by a pin. The second ends of the first auxiliary scale 6 and the second auxiliary scale 7 are respectively provided with coaxial hinge holes 20 (circular through holes). The inner diameters of the two hinge holes 20 are the same and their axes coincide. The inner diameter of the hinge hole 20 is slightly larger than the outer diameter of the pin, ensuring that the pin can rotate freely while preventing the auxiliary scale from wobbling due to excessive clearance. The pin includes a head and a mating section; the diameter of the head is larger than the inner diameter of the hinge hole 20, used to limit the pin's axial disengagement; the diameter of the mating section is adapted to the inner diameter of the hinge hole 20 and passes through the two hinge holes 20 to form a rotational fit.

[0093] When the pin is inserted into the two hinge holes 20, the first scale 6 and the second scale 7 can rotate relative to each other around the axis of the pin, allowing the two scales to be unfolded from the folded state (closely stored to save space) to a 90° angle, and can be positioned by the limiting protrusions or scales on the edge of the hinge hole 20.

[0094] When the two rulers are unfolded to 90°, the line connecting their hinge point (pin axis) and the contact part (A, B) of the two workpieces (AB) forms a right triangle (the hinge point is the right angle vertex). According to geometric principles, the midpoint of the line AB is the center of the circular end face of the workpiece being measured. The stability of the hinge structure directly ensures the straightness of the line AB, thereby ensuring the accuracy of the center positioning.

[0095] In one embodiment, the first end clip 2 is fixedly disposed at the first end of the base scale 1 (one end along the length direction of the base scale 1) and located on the front side of the base scale 1; the working surface of the first end clip 2 (the surface in contact with the workpiece being measured) is perpendicular to the length direction (axial direction) of the base scale 1. The second end clip 5 is fixed to the measuring end of the vernier scale 3 (on the side near the first end clip 2), the second end clip 5 is disposed parallel to the first end clip 2, the working surface of the second end clip 5 is parallel to the working surface of the first end clip 2, and the two are disposed opposite to each other along the axial direction of the base scale 1 (i.e., the working surfaces face opposite directions, forming a "clamping" structure); since the vernier scale 3 and the axial groove 4 of the base scale 1 slide together, the second end clip 5 always maintains a parallel relationship with the first end clip 2 when sliding with the vernier scale 3, ensuring that the direction of the force when contacting the workpiece being measured is consistent.

[0096] In this embodiment, the working surfaces of both the first end clamp 2 and the second end clamp 5 are machined as planes, or designed as adaptable arc surfaces (with curvature radii matching common workpiece edges) according to the workpiece being measured (such as the arc-shaped end face of a tamping hammer); the first end clamp 2 is perpendicular to the base scale 1, ensuring that the contact direction of its working surface is perpendicular to the axis (diameter measurement direction) of the base scale 1, avoiding the contact point from deviating from the diameter measurement area due to tilting; the second end clamp 5 is parallel to and opposite to the first end clamp 2, ensuring that the clamping force of both on the workpiece is along the same straight line (consistent with the diameter direction), reducing lateral force interference during measurement and improving reading stability.

[0097] It should be noted that, for those skilled in the art, it is obvious that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this utility model is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this utility model. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0098] This utility model uses specific examples to illustrate its principles and implementation methods. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the idea of ​​this utility model. In summary, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A diameter measuring device, characterized in that, include: A base scale (1) is provided with an axial groove (4) along its length. The first end clip (2) is disposed on the front side of the base scale (1); Vernier scale (3), the vernier scale (3) is slidably fitted with the axial groove (4) of the base scale (1); the measuring end of the vernier scale (3) is provided with a second end clip (5), the second end clip (5) is arranged opposite to the first end clip (2), and the area opposite to the first end clip (2) and the second end clip (5) is the diameter measuring area; A diameter positioning ruler, comprising a first auxiliary ruler (6) and a second auxiliary ruler (7), wherein the first end of the first auxiliary ruler (6) is connected to the back side of the base ruler (1); the first end of the second auxiliary ruler (7) is slidably connected to the axial groove (4) of the base ruler (1); the diameter measuring area is the projection area along the direction from the front side to the back side as the measuring projection area; The second ends of the first auxiliary ruler (6) and the second auxiliary ruler (7) are hinged together; the area where the surfaces of the first auxiliary ruler (6) and the second auxiliary ruler (7) intersect with the measurement projection area is the workpiece contact area.

2. The diameter measuring device according to claim 1, characterized in that, The first auxiliary ruler (6) includes a first inner sidewall (8) and a first outer sidewall (9), with the first inner sidewall (8) and the first outer sidewall (9) arranged parallel to each other; the second auxiliary ruler (7) includes a second inner sidewall (10) and a second outer sidewall (11), with the second inner sidewall (10) and the second outer sidewall (11) arranged parallel to each other; the intersection of the first inner sidewall (8) and the second inner sidewall (10) is the inner intersection point (12), and the intersection of the first outer sidewall (9) and the second outer sidewall (11) is the outer intersection point (13).

3. The diameter measuring device according to claim 1, characterized in that, The vernier scale (3) is provided with a display (14) for displaying measurement data, and the display (14) is fixedly mounted on the vernier scale (3) by a clamp (15).

4. The diameter measuring device according to claim 3, characterized in that, The vernier scale (3) is provided with a handle (16), which is located at the end of the vernier scale (3) away from the second end card (5). The display (14) is located on the vernier scale (3) in the middle section between the second end card (5) and the handle (16).

5. The diameter measuring device according to claim 1, characterized in that, The vernier scale (3) is provided with a first slider (17), which slides in cooperation with the axial groove (4).

6. The diameter measuring device according to claim 5, characterized in that, The vernier scale (3) is slidably engaged with the axial groove (4) by two first sliders (17); one of the first sliders (17) is integrated on the vernier scale (3), and the other first slider (17) is disposed on the second end clip (5); the two first sliders (17) are distributed at intervals along the axial direction of the base scale (1), and any one of the first sliders (17) is slidably engaged with the side wall of the axial groove (4).

7. The diameter measuring device according to claim 1, characterized in that, The first end of the first auxiliary ruler (6) is rotatably connected to the base ruler (1) via a rotating shaft; the first end of the first auxiliary ruler (6) is provided with a first shaft hole (18); the rotating shaft includes an embedded section and a fixed section, the diameter of the embedded section is adapted to the first shaft hole (18) and embedded in the first shaft hole (18), and the fixed section is embedded in the preset mounting hole of the base ruler (1).

8. The diameter measuring device according to claim 7, characterized in that, The second auxiliary ruler (7) has a second shaft hole (19) at its first end. One end of the second slider is embedded in the second shaft hole (19), and the other end of the second slider extends into the axial groove (4) of the base ruler (1) and slides in cooperation with the axial groove (4).

9. The diameter measuring device according to claim 1, characterized in that, The second end of the first auxiliary ruler (6) and the second end of the second auxiliary ruler (7) are both provided with hinge holes (20), and the axes of the two hinge holes (20) coincide. The pin passes through the two hinge holes (20).

10. The diameter measuring device according to claim 1, characterized in that, The first end clip (2) is fixedly installed at the end of the base scale (1), and the first end clip (2) is perpendicular to the length direction of the base scale (1); the second end clip (5) is parallel to and opposite to the first end clip (2).

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