Correction reference device for pitch diameter measuring instrument

Abstract

The utility model discloses a calibration reference device for an intermediate diameter measuring instrument. The calibration reference device comprises a standard block. Wherein the pitch diameter measuring instrument is provided with a bottom plate and two measuring heads, and the standard block is provided with an axial reference part which is used for abutting against the bottom plate in the pitch diameter measuring instrument so as to support the bottom plate. The standard block is also provided with a first reference conical surface which is used for abutting against and contacting with one measuring head in the pitch diameter measuring instrument, and a second reference conical surface which is used for abutting against and contacting with the other measuring head in the pitch diameter measuring instrument. And the first reference conical surface and the second reference conical surface are positioned on the same conical surface and are respectively positioned below the axial reference part. According to the utility model, the contact conditions of the two measuring heads in the pitch diameter measuring instrument can be kept consistent in the actual measuring process and the radial calibration process, so that the measuring error can be eliminated, and the accuracy of pipe thread pitch diameter measurement is improved.

Description

Technical Field

[0001] The utility model relates to a calibration reference device for a middle diameter measuring instrument. Background Art

[0002] At present, an oil casing is a steel pipe used to support the well wall of an oil and gas well. Pipe threads are machined at the ends of the oil casings. The pipe threads are used to connect the oil casings and have a certain taper. The middle diameter of the pipe threads is one of the very important dimensions. At present, a middle diameter measuring instrument is generally used in the industry to measure the middle diameter of the pipe threads. A pipe thread external thread middle diameter measuring instrument is disclosed in a Chinese patent with the publication number CN205333041U. Before measurement, the pipe thread external thread middle diameter measuring instrument needs to be calibrated using a standard rod A and a standard rod B. Placing the standard rod B above the measuring head and sliding the measuring arm up and down can perform axial calibration on the measuring head. Placing the standard rod A between the two measuring heads and sliding the guide rail block left and right can perform radial calibration on the measuring head.

[0003] In the actual process of measuring the pipe threads, the two measuring heads need to abut against the tooth crests of the pipe threads. Since the pipe threads have a certain taper, the two measuring heads are equivalent to abutting and fitting against the conical surface where the tooth crests of the pipe threads are located. Therefore, both of the two measuring heads will have a certain inclination angle. However, during the radial calibration process, the two measuring heads respectively abut against the two end faces of the standard rod A. Since the two end faces of the standard rod A are two parallel planes, when the two measuring heads respectively abut against the two end faces of the standard rod A, neither of the two measuring heads is inclined. Thus, it can be seen that during the actual measurement of the pipe threads, the two measuring heads are equivalent to contacting and fitting against the conical surface and both have a certain inclination angle, while during the radial calibration, the two measuring heads are contacting and fitting against the two parallel end faces of the standard rod A and neither of the two measuring heads has an inclination angle, resulting in inconsistent contact conditions of the two measuring heads during the actual measurement process and during the radial calibration process, and further bringing a certain measurement error, leading to inaccurate measurement of the middle diameter of the pipe threads. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is to overcome the defects of the prior art and provide a calibration reference device for a middle diameter measuring instrument, which can make the contact conditions of the two measuring heads in the middle diameter measuring instrument consistent during the actual measurement process and during the radial calibration process, thereby eliminating measurement errors and improving the accuracy of measuring the middle diameter of the pipe threads.

[0005] To solve the above technical problem, the technical solution of the utility model is: a calibration reference device for a middle diameter measuring instrument, including a standard block;

[0006] The middle diameter measuring instrument has a bottom plate and two measuring heads;

[0007] The standard block is provided with an axial reference portion for abutting against the bottom plate in the mid-diameter measuring instrument to support the bottom plate.

[0008] The standard block is further provided with a first reference conical surface for abutting against one of the measuring heads in the mid-diameter measuring instrument and a second reference conical surface for abutting against the other measuring head in the mid-diameter measuring instrument.

[0009] The first reference conical surface and the second reference conical surface are located on the same conical surface and are respectively located below the axial reference portion.

[0010] Furthermore, a specific structure of the axial reference portion is provided. The mid-diameter measuring instrument includes two guide blocks and two bottom plates. One of the bottom plates is connected to the lower end of one of the guide blocks, and the other bottom plate is connected to the lower end of the other guide block.

[0011] The axial reference portion includes a first axial reference surface for supporting one of the bottom plates and a second axial reference surface for supporting the other bottom plate.

[0012] Furthermore, the calibration reference device for the mid-diameter measuring instrument may further include a standard plate. The standard plate includes a plate body detachably connected to the top of the standard block.

[0013] One end of the plate body is provided with a first reference rod portion and a first supporting plate portion for supporting one of the bottom plates.

[0014] The other end of the plate body is provided with a second reference rod portion and a second supporting plate portion for supporting the other bottom plate.

[0015] The first reference rod portion is located below the first supporting plate portion and is used for abutting against the upper end of one of the measuring heads to calibrate the position of the measuring head.

[0016] The second reference rod portion is located below the second supporting plate portion and is used for abutting against the upper end of the other measuring head to calibrate the position of the measuring head.

[0017] Furthermore, both the first supporting plate portion and the second supporting plate portion bulge upward.

[0018] Furthermore, both the first axial reference surface and the second axial reference surface are higher than the upper surface of the plate body.

[0019] Furthermore, both the first reference rod portion and the second reference rod portion are connected to the bottom of the plate body and extend downward.

[0020] Furthermore, the first reference rod portion is located on one side of the standard block, and the second reference rod portion is located on the other side of the standard block.

[0021] Further, an installation groove is provided at the top of the standard block, and the plate body is detachably connected in the installation groove.

[0022] Further, a positioning groove is provided at the side portion of the plate body, and a positioning boss for being snap-fitted in the positioning groove to position the plate body is provided in the installation groove.

[0023] Further, the calibration reference device for the pitch diameter measuring instrument further includes a base, and the standard block is connected to the upper end portion of the base.

[0024] After adopting the above technical solution, when using a pitch diameter measuring instrument to measure a pipe thread, it is necessary to make the bottom plate in the pitch diameter measuring instrument abut against the end face of the pipe thread, and make the two measuring heads respectively abut against and fit with the tooth crest of the pipe thread. Since the pipe thread has a certain taper, the two measuring heads are equivalent to abutting against and fitting with the conical surface where the tooth crest of the pipe thread is located. Therefore, both of the two measuring heads will have a certain inclination angle. When performing radial calibration on the pitch diameter measuring instrument, it is necessary to make the bottom plate in the pitch diameter measuring instrument abut against the axial reference portion, and make one of the measuring heads abut against and fit with the first reference conical surface, and make the other measuring head abut against and fit with the second reference conical surface. At this time, the two measuring heads are equivalent to abutting against and fitting with the conical surface where the first reference conical surface and the second reference conical surface are located together. Therefore, both of the two measuring heads will have a certain inclination angle. Moreover, the first reference conical surface and the second reference conical surface are made by imitating the size and taper of the pipe thread. Therefore, the conical surface where the first reference conical surface and the second reference conical surface are located together is theoretically exactly the same as the conical surface where the tooth crest of the pipe thread is located. Therefore, the contact conditions of the two measuring heads during the actual measurement of the pipe thread using the pitch diameter measuring instrument and during the radial calibration of the pitch diameter measuring instrument are the same, thereby being able to eliminate measurement errors and improve the accuracy of the pitch diameter measurement of the pipe thread. Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of a pitch diameter measuring instrument in the prior art;

[0026] Figure 2 It is a schematic structural diagram of the present utility model when performing radial calibration on a pitch diameter measuring instrument;

[0027] Figure 3 It is a schematic structural diagram of the present utility model when performing axial calibration on a pitch diameter measuring instrument;

[0028] Figure 4 It is a schematic structural diagram of the calibration reference device for the pitch diameter measuring instrument of the present utility model;

[0029] Figure 5Exploded assembly view of the calibration reference device for the pitch diameter measuring instrument of the present utility model. Detailed implementation manners

[0030] In order to make the content of the present utility model easier to be clearly understood, the present utility model will be further described in detail below according to specific embodiments in conjunction with the accompanying drawings.

[0031] As Figures 1 to 5 shown, a calibration reference device for a pitch diameter measuring instrument includes a standard block 3;

[0032] Wherein, the pitch diameter measuring instrument has a bottom plate 1 and two measuring heads 2;

[0033] An axial reference portion for abutting against the bottom plate 1 in the pitch diameter measuring instrument to support the bottom plate 1 is provided on the standard block 3;

[0034] A first reference conical surface 4 for abutting against one of the measuring heads 2 in the pitch diameter measuring instrument and a second reference conical surface 5 for abutting against the other measuring head 2 in the pitch diameter measuring instrument are further provided on the standard block 3;

[0035] The first reference conical surface 4 and the second reference conical surface 5 are located on the same conical surface and are respectively located below the axial reference portion. Specifically, when using the pitch diameter measuring instrument to measure the pipe thread, it is necessary to make the bottom plate 1 in the pitch diameter measuring instrument abut against the end face of the pipe thread, and make the two measuring heads 2 respectively abut against and fit with the tooth crest of the pipe thread. Since the pipe thread has a certain taper, the two measuring heads 2 are equivalent to abutting against and fitting with the conical surface where the tooth crest of the pipe thread is located. Therefore, both of the two measuring heads 2 will have a certain inclination angle. When performing radial calibration on the pitch diameter measuring instrument, it is necessary to make the bottom plate 1 in the pitch diameter measuring instrument abut against the axial reference portion, and make one of the measuring heads 2 abut against and fit with the first reference conical surface 4, and make the other measuring head 2 abut against and fit with the second reference conical surface 5. At this time, the two measuring heads 2 are equivalent to abutting against and fitting with the conical surface where the first reference conical surface 4 and the second reference conical surface 5 are located together. Therefore, both of the two measuring heads 2 will have a certain inclination angle. Moreover, the first reference conical surface 4 and the second reference conical surface 5 are made by imitating the size and taper of the pipe thread. Therefore, the conical surface where the first reference conical surface 4 and the second reference conical surface 5 are located together is theoretically exactly the same as the conical surface where the tooth crest of the pipe thread is located. Therefore, the contact conditions of the two measuring heads 2 are the same during the actual measurement process of the pipe thread using the pitch diameter measuring instrument and during the radial calibration process of the pitch diameter measuring instrument. Furthermore, the measurement error can be eliminated, and the accuracy of the pitch diameter measurement of the pipe thread is improved.

[0036] As Figures 1 to 5As shown, the mid-diameter measuring instrument may include two guide rail blocks 6 and two of the base plates 1, with one of the base plates 1 connected to the lower end of one of the guide rail blocks 6 and the other base plate 1 connected to the lower end of the other guide rail block 6;

[0037] The axial reference portion may include a first axial reference surface 7 for supporting one of the base plates 1 and a second axial reference surface 8 for supporting the other base plate 1.

[0038] As Figures 1 to 5 shown, the calibration reference device for the mid-diameter measuring instrument may further include a standard plate, and the standard plate includes a plate body 9 detachably connected to the top of the standard block 3;

[0039] One end of the plate body 9 is provided with a first reference rod portion 10 and a first supporting plate portion 11 for supporting one of the base plates 1;

[0040] The other end of the plate body 9 is provided with a second reference rod portion 12 and a second supporting plate portion 13 for supporting the other base plate 1;

[0041] The first reference rod portion 10 is located below the first supporting plate portion 11 and is used to abut against the upper end of one of the measuring heads 2 to calibrate the position of the measuring head 2;

[0042] The second reference rod portion 12 is located below the second supporting plate portion 13 and is used to abut against the upper end of the other measuring head 2 to calibrate the position of the measuring head 2.

[0043] Specifically, when in use, take out the standard block 3 and the standard plate from the storage box, and then install the standard plate on the top of the standard block 3. After use, detach the standard plate from the standard block 3, and then put the standard block 3 and the standard plate into the storage box.

[0044] More specifically, the mid-diameter measuring instrument may include a guide rail arm 14, two guide rail blocks 6, a first measuring arm 15, a second measuring arm 16, an indicating gauge 17 and two measuring heads 2; wherein, the two guide rail blocks 6 are respectively slidably arranged on the guide rail arm 14, and the lower ends of the two guide rail blocks 6 are respectively connected with the base plates 1; the first measuring arm 15 is slidably connected to one of the guide rail blocks 6, and the second measuring arm 16 is slidably connected to the other guide rail block 6; the indicating gauge 17 is connected to the first measuring arm 15, one of the measuring heads 2 is connected to the indicating gauge 17, and the other measuring head 2 is connected to the second measuring arm 16.

[0045] Among them, for the convenience of description, the measuring head 2 connected to the dial indicator 17 is called the movable measuring head, and the measuring head 2 connected to the second measuring arm 16 is called the fixed measuring head. First, perform axial calibration. As Figure 3 shown, after installing the standard plate on the top of the standard block 3, let the first support plate portion 11 support one of the bottom plates 1, let the second support plate portion 13 support the other bottom plate 1, move the movable measuring head below the first reference rod portion 10, and move the fixed measuring head below the second reference rod portion 12; then slide the first measuring arm 15 upward so that the upper end portion of the movable measuring head abuts against the lower end surface of the first reference rod portion 10, slide the second measuring arm 16 upward so that the upper end portion of the fixed measuring head abuts against the lower end surface of the second reference rod portion 12, then lock the first bolt 22 and the second bolt 23 to lock the first measuring arm 15 and the second measuring arm 16, and then move the mid-diameter measuring instrument laterally to remove the mid-diameter measuring instrument from the standard plate. Then perform radial calibration. As Figure 2 shown, let the first axial reference surface 7 support one of the bottom plates 1, let the second axial reference surface 8 support the other bottom plate 1, make the movable measuring head abut against the first reference conical surface 4, make the fixed measuring head abut against the second reference conical surface 5, slide the two guide rail blocks 6 so that the measuring rod of the dial indicator 17 has an appropriate compression amount, and then lock the third bolt 24 and the fourth bolt 25 to lock the two guide rail blocks 6. Then keep the position of the fixed measuring head fixed, make the movable measuring head swing in a small arc, and after finding the inflection point of the pointer in the dial indicator 17, rotate the bezel of the dial indicator 17 so that the zero line of the scale disk aligns with the pointer, and then lock the bezel, and then remove the mid-diameter measuring instrument from the standard block 3, and the radial calibration is completed.

[0046] As Figures 2 to 5 shown, both the first support plate portion 11 and the second support plate portion 13 bulge upward.

[0047] As Figures 2 to 5 shown, both the first axial reference surface 7 and the second axial reference surface 8 are higher than the upper surface of the plate body 9.

[0048] As Figures 2 to 5 shown, both the first reference rod portion 10 and the second reference rod portion 12 are connected to the bottom of the plate body 9 and extend downward. The first reference rod portion 10 is located on one side of the standard block 3, and the second reference rod portion 12 is located on the other side of the standard block 3.

[0049] As Figures 2 to 5As shown, an installation groove 18 is provided at the top of the standard block 3, and the plate body 9 is detachably connected in the installation groove 18; specifically, the plate body 9 can be detachably connected in the installation groove 18 through fasteners.

[0050] As Figures 2 to 5 shown, a positioning groove 19 is provided at the side of the plate body 9, and a positioning boss 20 for being clamped in the positioning groove 19 to position the plate body 9 is provided in the installation groove 18.

[0051] As Figures 2 to 5 shown, the calibration reference device for the pitch diameter measuring instrument may further include a base 21, and the standard block 3 is connected to the upper end of the base 21; in this embodiment, the standard block 3 and the base 21 are integrally formed.

[0052] In summary, when using a pitch diameter measuring instrument to measure a pipe thread, it is necessary to make the bottom plate 1 in the pitch diameter measuring instrument abut against the end face of the pipe thread, and make the two measuring heads 2 respectively abut against and fit with the tooth crest of the pipe thread. Since the pipe thread has a certain taper, the two measuring heads 2 are equivalent to abutting against and fitting with the conical surface where the tooth crest of the pipe thread is located. Therefore, both of the two measuring heads 2 will have a certain inclination angle. When performing radial calibration on the pitch diameter measuring instrument, it is necessary to make the bottom plate 1 in the pitch diameter measuring instrument abut against the axial reference portion, and make one of the measuring heads 2 abut against and fit with the first reference conical surface 4, and make the other measuring head 2 abut against and fit with the second reference conical surface 5. At this time, the two measuring heads 2 are equivalent to abutting against and fitting with the conical surface where the first reference conical surface 4 and the second reference conical surface 5 are located together. Therefore, both of the two measuring heads 2 will have a certain inclination angle. Moreover, the first reference conical surface 4 and the second reference conical surface 5 are made by imitating the size and taper of the pipe thread. Therefore, the conical surface where the first reference conical surface 4 and the second reference conical surface 5 are located together is theoretically completely the same as the conical surface where the tooth crest of the pipe thread is located. Therefore, the contact conditions of the two measuring heads 2 during the actual measurement of the pipe thread using the pitch diameter measuring instrument and during the radial calibration of the pitch diameter measuring instrument are the same, thereby being able to eliminate measurement errors and improve the accuracy of the pitch diameter measurement of the pipe thread.

[0053] The above specific embodiments have further elaborated in detail on the technical problems solved, technical solutions, and beneficial effects of the present invention. It should be understood that the above is only the specific embodiments of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A calibration reference device for a mid-diameter measuring instrument. The mid-diameter measuring instrument has a base plate (1) and two measuring heads (2), and is characterized in that, It includes a standard block (3); An axial reference portion for abutting against the bottom plate (1) in the mid-diameter measuring instrument to support the bottom plate (1) is provided on the standard block (3); A first reference conical surface (4) for abutting against one of the measuring heads (2) in the mid-diameter measuring instrument and a second reference conical surface (5) for abutting against the other measuring head (2) in the mid-diameter measuring instrument are further provided on the standard block (3); The first reference conical surface (4) and the second reference conical surface (5) are located on the same conical surface and are respectively located below the axial reference portion; Among them, the mid-diameter measuring instrument includes two guide rail blocks (6) and two bottom plates (1), one of the bottom plates (1) is connected to the lower end of one of the guide rail blocks (6), and the other bottom plate (1) is connected to the lower end of the other guide rail block (6); The axial reference portion includes a first axial reference surface (7) for supporting one of the bottom plates (1) and a second axial reference surface (8) for supporting the other bottom plate (1); Among them, the calibration reference device for the mid-diameter measuring instrument further includes a standard plate, and the standard plate includes a plate body (9) detachably connected to the top of the standard block (3); One end of the plate body (9) is provided with a first reference rod portion (10) and a first supporting plate portion (11) for supporting one of the bottom plates (1); The other end of the plate body (9) is provided with a second reference rod portion (12) and a second supporting plate portion (13) for supporting the other bottom plate (1); The first reference rod portion (10) is located below the first supporting plate portion (11) and is used for abutting against the upper end of one of the measuring heads (2) to calibrate the position of the measuring head (2); The second reference rod portion (12) is located below the second supporting plate portion (13) and is used for abutting against the upper end of the other measuring head (2) to calibrate the position of the measuring head (2).

2. The calibration reference device for the pitch diameter measuring instrument according to claim 1, wherein, Both the first supporting plate portion (11) and the second supporting plate portion (13) bulge upward.

3. The calibration reference device for the pitch diameter measuring instrument according to claim 1, characterized in that, Both the first axial reference surface (7) and the second axial reference surface (8) are higher than the upper surface of the plate body (9).

4. The calibration reference device for the pitch diameter measuring instrument according to claim 1, wherein Both the first reference rod portion (10) and the second reference rod portion (12) are connected to the bottom of the plate body (9) and extend downward.

5. The calibration reference device for the pitch diameter measuring instrument according to claim 4, characterized in that, The first reference rod portion (10) is located on one side of the standard block (3), and the second reference rod portion (12) is located on the other side of the standard block (3).

6. The calibration reference device for the pitch diameter measuring instrument according to claim 1, characterized in that, An installation groove (18) is provided at the top of the standard block (3), and the plate body (9) is detachably connected in the installation groove (18).

7. The calibration reference device for the pitch diameter measuring instrument according to claim 6, characterized in that, A positioning groove (19) is provided at the side of the plate body (9), and a positioning boss (20) for being clamped in the positioning groove (19) to position the plate body (9) is provided in the installation groove (18).

8. The calibration reference device for the pitch diameter measuring instrument according to claim 1, characterized in that, It further includes a base (21), and the standard block (3) is connected to the upper end of the base (21).

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