Device for measuring outer diameter of rectangular steel pipe

Abstract

The utility model discloses a device for measuring the outer diameter of a rectangular steel pipe, and belongs to the technical field of rectangular steel pipe measuring equipment. The device for measuring the outer diameter of the rectangular steel pipe comprises a bottom plate, two supporting plates, a first support, four second supports, sixteen first screws, sixteen second screws, four supporting blocks, sixteen positioning rods, eight measuring rods, sixteen linear bearings, four first connecting rods, four second connecting rods, four screw rods and four nuts. The device can quickly position the rectangular steel pipe and quickly measure and calculate the outer diameter of the rectangular steel pipe, and has the characteristics of low manufacturing cost, simplicity in operation and good use effect.

Description

Technical Field

[0001] The utility model belongs to the technical field of steel pipe measurement, and particularly relates to a device for measuring the outer diameter of a rectangular steel pipe. Background Art

[0002] At present, enterprises usually adopt the method of hot rolling piercing + continuous rolling tube to produce steel pipes. Compared with profiles of other cross-sections, steel pipes have relatively high resistance to bending and torsion. Compared with circular steel pipes, rectangular steel pipes have relatively large stress areas and stable structural properties. Therefore, rectangular steel pipes are widely used in the fields of mechanical manufacturing and structural engineering. The external dimensions of rectangular steel pipes directly affect their service performance and processing performance. Therefore, many mechanical processing industries using rectangular steel pipes as raw materials have strict requirements for the outer diameter of rectangular steel pipes. Since there are relatively few devices for professionally measuring the outer diameter of rectangular steel pipes, enterprises usually use vernier calipers to measure the outer diameter of rectangular steel pipes, but the measurement accuracy of this method is relatively limited.

[0003] After retrieval, it is found that there are three patent literatures most relevant to the technology of the utility model, and the specific contents are described as follows.

[0004] Patent document CN 201520144284.1 discloses a multi-functional detector for the inner and outer diameters of steel pipes, which mainly includes a scale body, an outer vernier block, an inner vernier block, fixed jaws, outer jaws, inner jaws, an outer sliding sleeve, an inner sliding sleeve and a locking bolt. Based on the positive and negative tolerances of the inner and outer diameters of the standard sample pipe, the patent device jointly uses the inner vernier block and the outer vernier block to quickly perform qualitative screening measurements on the inner and outer diameters of steel pipes. However, based on the design principle of the vernier caliper, the measurement accuracy of the patent device is relatively limited.

[0005] Patent document CN 201620808231.X discloses an automatic detection device for the outer diameters of both ends of a steel pipe, which mainly includes a cylinder seat, a measuring cylinder, a measuring sleeve, a top material shaft, an indicator light, an adjusting handle, a frame, a pressing cylinder, a pressing head, a V-shaped support and a slide rail. The patent device can automatically detect the outer diameters of both ends of the steel pipe at the same time, and the working efficiency is relatively high. However, since the patent device also does not have an accurate measurement system, the measurement accuracy of the patent device is also relatively limited.

[0006] Patent document CN 201721141979.X discloses a steel pipe outer diameter detection device, which mainly includes a hollow mounting seat, a mounting shell, a fixing plate, a belt pulley, a motor, a rotating rod, a slider, a T-shaped connecting block, a positioning clamping block and a laser rangefinder. Although the measurement accuracy of the patent device is relatively high, due to the relatively complex structure of the patent device, the manufacturing cost of the patent device is relatively high. Content of the Utility Model

[0007] In order to overcome one or more of the problems existing in the prior art, the present utility model provides a device for measuring the outer diameter of a rectangular steel pipe. The device of the present utility model is designed with a symmetric structure. The combined use of the first bracket and the bottom plate can enable the rectangular steel pipe to be arranged along the vertical direction; the combined use of the support plate and the positioning rod can achieve the positioning of the rectangular steel pipe; the combined use of the support plate, the support block, the first connecting rod, the second connecting rod and the linear bearing can enable the second bracket to move along a predetermined trajectory; the combined use of the eight scale segments of the eight measuring rods and the eight fourth convex platforms of the four second brackets can form eight micrometers, so as to accurately calculate the outer diameters of the rectangular steel pipe at four different positions; since the present utility model is based on the scientific concept of taking the average value through multiple measurements to reduce the gap between the measured value and the true value, thereby improving the measurement accuracy. Therefore, the use effect of the device of the present utility model is relatively good.

[0008] The device for measuring the outer diameter of a rectangular steel pipe provided by the present utility model includes: a bottom plate, two support plates, a first bracket, four second brackets, sixteen first screws, sixty-four second screws, four support blocks, sixteen positioning rods, eight measuring rods, sixteen linear bearings, four first connecting rods, four second connecting rods, four screw rods and four nuts, wherein:

[0009] The support plate is a symmetric structure in the shape of a cuboid. Four groups, a total of eight cylindrical fourth through holes are symmetrically opened at the corner positions of the support plate. The first screws are passed through the fourth through holes; a cuboid-shaped fifth through hole is opened at the central part of the support plate, and the fifth through hole is used for passing a rectangular steel pipe; two first screw holes are respectively opened on the front and rear end faces of the support plate, and the positioning rods are screwed into the first screw holes; two second screw holes are respectively opened on the left and right end faces of the support plate, and the positioning rods are screwed into the second screw holes; a set of scales are respectively marked on the end faces of the support plate, so as to be able to mark the positions of the four relatively arranged second brackets.

[0010] The first bracket is composed of a first body and a first convex platform connected. Both the first body and the first convex platform are symmetric structures in the shape of a cuboid. The first convex platform is located on the upper end face of the first body; four cylindrical second through holes are symmetrically opened on the first body, and the screw rods are passed through the second through holes; a cuboid-shaped third through hole is opened at the central part of the first convex platform, and the third through hole is used for passing a rectangular steel pipe, and the third through hole also penetrates through the first body.

[0011] The second bracket is composed of a fourth body and two fourth bosses connected thereto. The two fourth bosses are arranged oppositely and are both located on the rear end face of the fourth body. The fourth body is a cuboid-shaped symmetric structure, and two cylindrical eighth through holes are symmetrically formed in the fourth body. A third boss of the linear bearing is inserted into the eighth through hole. Four third screw holes are evenly formed around the eighth through hole, and second screws are screwed into the third screw holes. The fourth boss is a cylinder-shaped symmetric structure, and fifty division scales are evenly marked on the side surface of the fourth boss in the circumferential direction. A fourth screw hole is formed at the axis position of the fourth boss, and a measuring rod is screwed into the fourth screw hole. The fourth screw hole also penetrates through the fourth body.

[0012] The support block is a cuboid-shaped symmetric structure, and a cuboid-shaped third through groove is formed at the corner position of the support block. Two cylindrical grooves are respectively formed on the two vertical end faces of the support block, and the ends of the first connecting rod or the second connecting rod are inserted into the grooves. Two fifth screw holes are respectively formed on the upper and lower end faces of the support block, and first screws are screwed into the fifth screw holes.

[0013] The positioning rod is composed of three parts: a coaxial first contact section, a first threaded section, and a second contact section connected together. The first threaded section is a cylinder-shaped symmetric structure with threads on the side surface and is used for screwing into the first screw hole or the second screw hole of the support plate. Both the first contact section and the second contact section are cylinder-shaped symmetric structures and are used for contacting the outer surface of the rectangular steel pipe.

[0014] The measuring rod is composed of three parts: a coaxial third contact section, a second threaded section, and a scale section connected together. The third contact section is a hemispherical symmetric structure and is used for contacting the outer surface of the rectangular steel pipe. The second threaded section is a cylinder-shaped symmetric structure with threads on the side surface and is used for screwing into the fourth screw hole of the second bracket. The pitch value of the thread is 0.5 mm. The scale section is a cylinder-shaped symmetric structure, and four groups of scales are evenly marked on the side surface of the cylinder in the circumferential direction. Each group of scales is composed of adjacent left and right columns of offset scales. The offset value of the two columns of offset scales is 0.5 mm, and the minimum division value of the offset scales is 1 mm.

[0015] The linear bearing is composed of a third body and a third boss. The third boss is located at the right end face of the third body. The third body is a cuboid-shaped symmetric structure, and four cylindrical sixth through holes are symmetrically provided in the third body. The second screw is inserted through the sixth through holes. The third boss is a cylindrical symmetric structure. A cylindrical seventh through hole is provided at the axis part of the third boss. The first connecting rod or the second connecting rod is inserted through the seventh through hole, and the seventh through hole also penetrates through the third body. A cage, balls and a retaining ring are further provided in the third boss.

[0016] The first connecting rod is a cylindrical symmetric structure. The two end parts of the first connecting rod are inserted into the grooves of the support block, and the middle part of the first connecting rod is inserted into the seventh through hole of the linear bearing.

[0017] The second connecting rod is a cylindrical symmetric structure. The two end parts of the second connecting rod are inserted into the grooves of the support block, and the middle part of the second connecting rod is inserted into the seventh through hole of the linear bearing.

[0018] In some embodiments, the bottom plate is a cuboid-shaped symmetric structure, and four cylindrical first through holes are symmetrically provided in the bottom plate. The screw rod is inserted through the first through holes.

[0019] In some embodiments, the first screw is connected and composed of a coaxial second body and a second boss. Both the second body and the second boss are cylindrical symmetric structures. The second boss is located at the lower end face of the second body. Threads are provided at the end of the second boss for screwing into the fifth screw hole of the support block. A cuboid-shaped first through groove is provided on the upper end face of the second body to facilitate screwing the first screw.

[0020] In some embodiments, the second screw is connected and composed of a coaxial fifth body and a fifth boss. Both the fifth body and the fifth boss are cylindrical symmetric structures. The fifth boss is located at the right end face of the fifth body. Threads are provided at the end of the fifth boss for screwing into the third screw hole of the second bracket. A cuboid-shaped second through groove is provided on the left end face of the fifth body to facilitate screwing the second screw.

[0021] In some embodiments, a nut is screwed onto the threaded end of the screw rod.

[0022] In some embodiments, both the screw rod and the nut are standard parts.

[0023] Advantageous effects: The advantageous effects of the present utility model are as follows:

[0024] The device of the utility model comprises a base plate, two support plates, a first bracket, four second brackets, sixteen first screws, sixty-four second screws, four support blocks, sixteen positioning rods, eight measuring rods, sixteen linear bearings, four first connecting rods, four second connecting rods, four screw rods and four nuts. Since the materials are common and easy to process and form, the manufacturing cost of the device of the utility model is relatively low.

[0025] When using the device of the utility model, rotate the eight measuring rods to the zero scale position, pass the rectangular steel pipe through the third through hole of the first bracket, sleeve the device of the utility model outside the rectangular steel pipe, tighten the sixteen positioning rods respectively, move the four second brackets to the parts of the rectangular steel pipe where the outer diameter needs to be measured along the first connecting rod and the second connecting rod, screw in the eight measuring rods, and make the eight third contact sections contact the outer surface of the rectangular steel pipe respectively, and read △a i , △b i , △c i and △e i respectively, measure m, w and r, calculate the two outer diameters Da 1 b 1 and Da 2 b 2 between the front and rear end faces of the rectangular steel pipe, and then calculate the outer diameter Dab; calculate the two outer diameters Dc 1 e 1 and Dc 2 e 2 between the left and right end faces of the rectangular steel pipe, and then calculate the outer diameter Dce. Therefore, the operation of the device of the utility model is relatively simple.

[0026] The device of the utility model is designed with a symmetrical structure. The combined use of the first bracket and the base plate can realize the vertical setting of the rectangular steel pipe; the combined use of the support plate and the positioning rod can realize the positioning of the rectangular steel pipe; the combined use of the support plate, the support block, the first connecting rod, the second connecting rod and the linear bearing can realize the movement of the second bracket along a predetermined track; the combined use of the eight scale segments of the eight measuring rods and the eight fourth convex platforms of the four second brackets can form eight micrometers, so as to accurately measure the outer diameters of the rectangular steel pipe at four different parts; since the utility model is based on the scientific concept of taking the average value through multiple measurements to reduce the gap between the measured value and the true value and improve the measurement accuracy, the use effect of the device of the utility model is relatively good.

[0027] Through the device for measuring the outer diameter of a rectangular steel pipe provided by the utility model, the purpose of quickly positioning the rectangular steel pipe and quickly measuring the outer diameter of the rectangular steel pipe can be achieved. The device of the utility model has the characteristics of low manufacturing cost, simple operation and good use effect. Description of the Drawings

[0028] Figure 1 This is the front view structural schematic diagram of the device for measuring the outer diameter of a rectangular steel pipe of the present utility model before measurement;

[0029] Figure 2 This is the left view structural schematic diagram of the device for measuring the outer diameter of a rectangular steel pipe of the present utility model before measurement;

[0030] Figure 3 This is the top view structural schematic diagram of the device for measuring the outer diameter of a rectangular steel pipe of the present utility model before measurement;

[0031] Figure 4 This is the top view structural schematic diagram of the device for measuring the outer diameter of a rectangular steel pipe of the present utility model during measurement;

[0032] Figure 5 This is the schematic diagram of the mutual positional relationship of the second support, linear bearing and second screw of the present utility model;

[0033] Figure 6 This is the schematic diagram of the mutual positional relationship of the support block, first connecting rod, second connecting rod, linear bearing and second support of the present utility model;

[0034] Figure 7 This is the top view structural schematic diagram of the bottom plate of the present utility model;

[0035] Figure 8 This is the front view structural schematic diagram of the first support of the present utility model;

[0036] Figure 9 This is the top view structural schematic diagram of the first support of the present utility model;

[0037] Figure 10 This is the front view structural schematic diagram of the first screw of the present utility model;

[0038] Figure 11 This is the front view structural schematic diagram of the support plate of the present utility model;

[0039] Figure 12 This is the left view structural schematic diagram of the support plate of the present utility model;

[0040] Figure 13 This is the top view structural schematic diagram of the support plate of the present utility model;

[0041] Figure 14 This is the top view structural schematic diagram of the positioning rod of the present utility model;

[0042] Figure 15 This is the front view structural schematic diagram of the linear bearing of the present utility model;

[0043] Figure 16It is a right view structural schematic diagram of the linear bearing of the present utility model;

[0044] Figure 17 It is a front view structural schematic diagram of the second bracket of the present utility model;

[0045] Figure 18 It is a left view structural schematic diagram of the second bracket of the present utility model;

[0046] Figure 19 It is a top view structural schematic diagram of the second bracket of the present utility model;

[0047] Figure 20 It is a front view structural schematic diagram of the second screw of the present utility model;

[0048] Figure 21 It is a front view structural schematic diagram of the support block of the present utility model;

[0049] Figure 22 It is a top view structural schematic diagram of the support block of the present utility model;

[0050] Figure 23 It is a top view structural schematic diagram of the measuring rod of the present utility model;

[0051] Figure 24 It is a schematic diagram of the working principle of the device for measuring the outer diameter of a rectangular steel pipe of the present utility model before measurement;

[0052] Figure 25 It is a schematic diagram of the working principle of the device for measuring the outer diameter of a rectangular steel pipe of the present utility model during measurement;

[0053] Figure 26 It is a schematic diagram of the four outer diameters measured by the device for measuring the outer diameter of a rectangular steel pipe of the present utility model.

[0054] Description of reference numerals: 1 - bottom plate; 101 - first through hole; 2 - first bracket; 201 - first body; 202 - first boss; 203 - second through hole; 204 - third through hole; 3 - first screw; 301 - second body; 302 - second boss; 303 - first through slot; 4 - support plate; 401 - first threaded hole; 402 - second threaded hole; 403 - fourth through hole; 404 - fifth through hole; 5 - positioning rod; 501 - first contact section; 502 - first threaded section; 503 - second contact section; 6 - linear bearing; 601 - third body; 602 - third boss; 603 - sixth through hole; 604 - seventh through hole; 7 - second bracket; 701 - fourth body; 702 - fourth boss; 703 - eighth through hole; 704 - third threaded hole; 705 - fourth threaded hole; 8 - second screw; 801 - fifth body; 802 - fifth boss; 803 - second through slot; 9 - support block; 901 - groove; 902 - third through slot; 903 - fifth threaded hole; 10 - measuring rod; 1001 - third contact section; 1002 - second threaded section; 1003 - scale section; 11 - first connecting rod; 12 - second connecting rod; 13 - screw; 14 - nut; 15 - rectangular steel pipe. Detailed implementation manners

[0055] The content of the present utility model will be described in detail below through embodiments and drawings. The embodiments are only used to understand the present utility model, rather than limiting the content of the present utility model.

[0056] Embodiment 1: Device for measuring the outer diameter of a rectangular steel pipe

[0057] Combined with Figures 1 to 6As shown in the figure, the utility model provides a device for measuring the outer diameter of a rectangular steel pipe, which comprises a bottom plate 1, two support plates 4, a first bracket 2, four second brackets 7, sixteen first screws 3, sixty-four second screws 8, four support blocks 9, sixteen positioning rods 5, eight measuring rods 10, sixteen linear bearings 6, four first connecting rods 11, four second connecting rods 12, four screw rods 13 and four nuts 14; wherein, the first bracket 2 is arranged on the bottom plate 1 and is connected by four screw rods 13 and four nuts 14; four support blocks 9 arranged in pairs are arranged between two relatively arranged support plates 4 and are connected by sixteen first screws 3; eight ends of four first connecting rods 11 are arranged in eight grooves 901 of four support blocks 9, and four middle parts of four first connecting rods 11 are arranged in eight seventh through holes 604 of eight linear bearings 6; eight third bosses 602 of eight linear bearings 6 are arranged in four eighth through holes 703 of two relatively arranged second brackets 7 and are connected by thirty-two second screws 8; eight ends of four second connecting rods 12 are arranged in eight other grooves 901 of four support blocks 9, and four middle parts of four second connecting rods 12 are arranged in eight seventh through holes 604 of eight other linear bearings 6; eight third bosses 602 of eight other linear bearings 6 are arranged in four eighth through holes 703 of two relatively arranged other second brackets 7 and are connected by thirty-two second screws 8; eight measuring rods 10 are screwed into eight fourth screw holes 705 of four second brackets 7, eight positioning rods 5 are screwed into eight first screw holes 401 of two support plates 4, and eight other positioning rods 5 are screwed into eight second screw holes 402 of two support plates 4.

[0058] Embodiment 2: Assembly process of the device for measuring the outer diameter of a rectangular steel pipe provided by the utility model

[0059] As Figures 1 to 23 shown in the figure, first, sixteen third bosses 602 of sixteen linear bearings 6 are arranged in eight eighth through holes 703 of four second brackets 7, and sixty-four sixth through holes 603 of sixteen linear bearings 6 and thirty-two third screw holes 704 of four second brackets 7 are aligned. Then, sixty-four second screws 8 are passed through sixty-four sixth through holes 603 and screwed into thirty-two third screw holes 704. In this way, sixteen linear bearings 6 and four second brackets 7 can be assembled;

[0060] Then, the middle parts of the four first connecting rods 11 and the four second connecting rods 12 are respectively inserted into the sixteen seventh through holes 604 of the sixteen linear bearings 6. Then, the four support blocks 9 are arranged in pairs opposite to each other. Then, the end parts of the four first connecting rods 11 and the four second connecting rods 12 are respectively inserted into the sixteen grooves 901 of the four support blocks 9. In this way, the four first connecting rods 11, the four second connecting rods 12, the sixteen linear bearings 6 and the four support blocks 9 can be assembled;

[0061] Then, a support plate 4 is arranged on the four support blocks 9, and the eight fourth through holes 403 of the support plate 4 are aligned with the eight fifth screw holes 903 located above the four support blocks 9. Then, eight first screws 3 are passed through the eight fourth through holes 403 and screwed into the eight fifth screw holes 903. In this way, a support plate 4 and the four support blocks 9 can be assembled;

[0062] Then, the assembled support plate 4 and the four support blocks 9 are turned over up and down. Then, another support plate 4 is arranged on the four support blocks 9, and the eight fourth through holes 403 of the support plate 4 are aligned with the other eight fifth screw holes 903 located above the four support blocks 9. Then, another eight first screws 3 are passed through the eight fourth through holes 403 and screwed into the eight fifth screw holes 903. In this way, another support plate 4 and the four support blocks 9 can be assembled;

[0063] Then, the bottom plate 1 is arranged on the installation table. Then, the first bracket 2 is arranged on the bottom plate 1, and the four second through holes 203 of the first bracket 2 are aligned with the four first through holes 101 of the bottom plate 1. Then, four screw rods 13 are inserted into the four groups of aligned through holes, and four nuts 14 are screwed onto the threaded ends of the four screw rods 13. In this way, the first bracket 2 and the bottom plate 1 can be assembled;

[0064] Then, eight measuring rods 10 are respectively screwed into the eight fourth screw holes 705 of the four second brackets 7. Then, sixteen positioning rods 5 are respectively screwed into the eight first screw holes 401 and the eight second screw holes 402 of the two support plates 4. In this way, the assembly of the whole device is completed and it can be put into use.

[0065] Embodiment 3: Working principle of the device for measuring the outer diameter of a rectangular steel pipe provided by the present utility model

[0066] As Figure 24 and Figure 25As shown, based on the scientific concept that taking the average value of multiple measurements can reduce measurement errors, for the convenience of description, the two measurement rods 10 in the front position are designated as a i (where i is a natural number), and the two measurement rods 10 in the rear position are designated as b i , the two measurement rods 10 on the left are designated as c i , and the two measurement rods 10 on the right are designated as e i . The distance between the two fourth bodies 701 of the two second brackets 7 arranged front and back is set as m, the distance between the two fourth bodies 701 of the two second brackets 7 arranged left and right is set as w, and the radius of the third contact section 1001 of the measurement rod 10 is set as r. Then, the eight third contact sections 1001 of the eight measurement rods 10 at the zero scale position just all extend out of the four fourth bodies 701 of the four second brackets 7, and the extended length is all r;

[0067] As Figure 25 shown, when measuring the outer diameter of the rectangular steel pipe 15, the eight measurement rods 10 are all tangent to the rectangular steel pipe 15; the a i , the b i , the c i , and the e i are respectively set as the lengths of the screwed-in △a i , △b i , △c i , and △e i . The outer diameter of the rectangular steel pipe 15 measured by the a i and the b i is set as Da i b i . The outer diameter of the rectangular steel pipe 15 measured by the c i and the e i is set as Dc i e i ; according to the knowledge point that the distance between parallel planes is equal everywhere, the following two equations can be obtained: r + △a i + Da i b i + r + △b i = m, r + △c i + Dc i e i + r + △e i = w. After sorting, the following two equations can be obtained: Da i b i = m - 2r - △a i - △b i , Dc i ei = w - 2r - Δc i - Δe i ;

[0068] As Figure 26 shown, the utility model is based on averaging two measurements, that is, i = 2. Measurements are taken at two positions on the front end face and the rear end face of the rectangular steel pipe 15 respectively, and at two positions on the left end face and the right end face of the rectangular steel pipe 15. The two measuring rods 10 in the front position are respectively a 1 and a 2 , the two measuring rods 10 in the rear position are respectively b 1 and b 2 , the two measuring rods 10 on the left are respectively c 1 and c 2 , the two measuring rods 10 on the right are respectively e 1 and e 2 . The outer diameters of two positions are measured by the four measuring rods 10 arranged front and rear, which are respectively Da 1 b 1 and Da 2 b 2 . The outer diameters of two positions are measured by the four measuring rods 10 arranged left and right, which are respectively Dc 1 e 1 and Dc 2 e 2 ; The outer diameter Dab of the rectangular steel pipe 15 = (Da 1 b 1 + Da 2 b 2 ) / 2, and the outer diameter Dce of the rectangular steel pipe 15 = (Dc 1 e 1 + Dc 2 e 2 ) / 2;

[0069] As Figure 24 and Figure 25 shown, the combined use of the eight scale segments 1003 of the eight measuring rods 10 and the eight fourth bosses 702 of the four second brackets 7 can form eight micrometers. The measurement accuracy of the eight micrometers can reach 0.01 mm. The reasoning process is as follows: Since the pitch value of the thread of the measuring rod 10 is 0.5 mm, that is, when the measuring rod 10 rotates one week, the axial distance that the measuring rod 10 moves within the fourth screw hole 705 is 0.5 mm. Since the side surface of the fourth boss 702 is evenly marked with fifty grid scales along the circumferential direction, therefore, when the measuring rod 10 rotates one grid scale, the axial distance that the measuring rod 10 moves within the fourth screw hole 705 is 0.01 mm.

[0070] Example 4: Usage process of the device for measuring the outer diameter of a rectangular steel pipe provided by the present utility model

[0071] Step 1: As shown in Figures 1 to 3 , first, all eight of the said measuring rods 10 are rotated to the zero scale position. Then, the rectangular steel pipe 15 is inserted through the third through-hole 204 of the first support 2. Then, the present utility model is sleeved outside the part of the rectangular steel pipe 15 to be measured. Then, the sixteen positioning rods 5 are respectively tightened, and the sixteen first contact segments 501 of the sixteen positioning rods 5 are respectively brought into contact with the outer surface of the rectangular steel pipe 15 to position the rectangular steel pipe 15;

[0072] Step 2: As shown in Figure 4 , then, along the four first connecting rods 11 and the four second connecting rods 12, the four second supports 7 are moved to the part of the rectangular steel pipe 15 to be measured. Then, the eight measuring rods 10 are respectively screwed in, and the eight third contact segments 1001 of the eight measuring rods 10 are respectively brought into contact with the outer surface of the rectangular steel pipe 15. At this time, the eight third contact segments 1001 of the eight measuring rods 10 are all in a tangent relationship with the rectangular steel pipe 15;

[0073] Step 3: As shown in Figure 25 and Figure 26 , then, the distances △a 1 , △a 2 , △b 1 , △b 2 , △c 1 , △c 2 , △e 1 and △e 2 screwed into by the eight measuring rods 10 are respectively read. Then, the distance m between the two fourth bodies 701 of the two second supports 7 set before and after measurement is measured. Then, the distance w between the two fourth bodies 701 of the two second supports 7 set on the left and right is measured. Then, the radius r of the third contact segment 1001 of the measuring rod 10 is measured;

[0074] Step 4: Through the formula Da i b i = m - 2r - △a i - △b i , the two outer diameters Da 1 b 1 and Da 2 b 2 between the front and rear end faces of the rectangular steel pipe 15 are calculated. Through the formula Dab = (Da 1 b 1 + Da 2 b2 ) / 2 to calculate the outer diameter Dab between the front and rear end faces of the rectangular steel pipe 15; through the formula Dc i e i = w - 2r - △c i - △e i , calculate the two outer diameters Dc 1 e 1 and Dc 2 e 2 , and through the formula Dce = (Dc 1 e 1 + Dc 2 e 2 ) / 2 to calculate the outer diameter Dce between the left and right end faces of the rectangular steel pipe 15.

[0075] Supplementary description: The device for measuring the outer diameter of a rectangular steel pipe provided by the present invention is designed with a symmetrical structure. The zero scale position refers to the position when the eight scale segments 1003 of the eight measuring rods 10 and the initial scales of the eight fourth convex platforms 702 of the four second brackets 7 are aligned. Since both the first contact section 501 and the second contact section 503 of the positioning rod 5 are cylindrical structures, this can ensure that the sixteen positioning rods 5 are in surface contact with the rectangular steel pipe 15. The two second brackets 7 arranged front and back should display the same scale on the two support plates 4. This can ensure that the two second brackets 7 arranged front and back are in an aligned relationship. The two second brackets 7 arranged left and right should display the same scale on the two support plates 4. This can ensure that the two second brackets 7 arranged left and right are in an aligned relationship.

[0076] It can be seen from the embodiments that by using the device for measuring the outer diameter of a rectangular steel pipe provided by the present invention, the rectangular steel pipe can be quickly positioned and the outer diameter of the rectangular steel pipe can be quickly measured. The device of the present invention has the characteristics of low manufacturing cost, simple operation and good use effect.

[0077] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. 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 perform equivalent replacements for some of the technical features.

Claims

1. A device for measuring the outer diameter of a rectangular steel pipe, characterized in that: The device for measuring the outer diameter of a rectangular steel pipe comprises: a base plate (1), two support plates (4), a first bracket (2), four second brackets (7), sixteen first screws (3), sixty-four second screws (8), four support blocks (9), sixteen positioning rods (5), eight measuring rods (10), sixteen linear bearings (6), four first connecting rods (11), four second connecting rods (12), four screw rods (13) and four nuts (14), wherein: The support plate (4) is a rectangular parallelepiped symmetrical structure, and four groups of eight cylindrical fourth through holes (403) are symmetrically provided at the corners of the support plate (4), and the first screws (3) are inserted into the fourth through holes (403); a rectangular parallelepiped fifth through hole (404) is provided at the center of the support plate (4), and a rectangular steel pipe is inserted into the fifth through hole (404); two first screw holes (401) are respectively provided at the front and rear end faces of the support plate (4), and the positioning rods (5) are screwed into the first screw holes (401); two second screw holes (402) are respectively provided at the left and right end faces of the support plate (4), and the positioning rods (5) are screwed into the second screw holes (402); the end faces of the support plate (4) are respectively marked with a group of scales so as to mark the positions of the four second brackets (7) arranged relatively to each other; The first bracket (2) is composed of a first body (201) and a first boss (202) connected together, the first body (201) and the first boss (202) are both rectangular parallelepiped symmetrical structures, and the first boss (202) is located on the upper end surface of the first body (201); the first body (201) is symmetrically provided with four cylindrical second through holes (203), and the screw rod (13) is passed through the second through holes (203); a rectangular parallelepiped third through hole (204) is provided at the center of the first boss (202), and a rectangular steel pipe is passed through the third through hole (204), and the third through hole (204) also passes through the first body (201); The second bracket (7) is composed of a fourth body (701) and two fourth bosses (702) connected together, the two fourth bosses (702) are arranged opposite to each other and are simultaneously located on the rear end surface of the fourth body (701); the fourth body (701) is a rectangular parallelepiped symmetrical structure, the fourth body (701) is symmetrically provided with two cylindrical eighth through holes (703), the third boss (602) of the linear bearing (6) is penetrated in the eighth through hole (703); the periphery of the eighth through hole (703) is provided with a plurality of Four third screw holes (704) are evenly provided, and the second screw (8) is screwed into the third screw holes (704); the fourth boss (702) is a cylindrical symmetrical structure, and fifty grid scales are evenly marked on the side surface of the fourth boss (702) along the circumferential direction; a fourth screw hole (705) is provided at the axial part of the fourth boss (702), and the measuring rod (10) is screwed into the fourth screw hole (705), and the fourth screw hole (705) also runs through the fourth body (701); The support block (9) is a rectangular parallelepiped symmetrical structure, and a rectangular parallelepiped third through groove (902) is provided at a corner of the support block (9); two vertical end faces of the support block (9) are respectively provided with two cylindrical grooves (901), and the ends of the first connecting rod (11) or the second connecting rod (12) are inserted into the grooves (901); the upper and lower end faces of the support block (9) are respectively provided with two fifth screw holes (903), and the first screw (3) is screwed into the fifth screw holes (903); The positioning rod (5) is composed of three coaxial parts: a first contact section (501), a first threaded section (502) and a second contact section (503); the first threaded section (502) is a cylindrical symmetrical structure with a threaded side surface, and is used to screw the first screw hole (401) or the second screw hole (402) of the support plate (4); the first contact section (501) and the second contact section (503) are both cylindrical symmetrical structures, and are used to contact the outer surface of the rectangular steel pipe; The measuring rod (10) is composed of three parts connected together, namely, a coaxial third contact section (1001), a second threaded section (1002) and a scale section (1003); the third contact section (1001) is a hemispherical symmetrical structure, used for contacting the outer surface of the rectangular steel tube; the second threaded section (1002) is a cylindrical symmetrical structure with a thread on the side, used for screwing the fourth screw hole (705) of the second bracket (7), the pitch value of the thread is 0.5 mm; the scale section (1003) is a cylindrical symmetrical structure, the side of the cylinder is evenly marked with four groups of scales along the circumferential direction, each group of scales is composed of two adjacent left and right columns of misaligned scales, the misalignment value of the two columns of misaligned scales is 0.5 mm, and the minimum grid value of the misaligned scales is 1 mm; The linear bearing (6) is composed of a third body (601) and a third boss (602), wherein the third boss (602) is located on the right end face of the third body (601); the third body (601) is a rectangular parallelepiped symmetrical structure, and the third body (601) is symmetrically provided with four cylindrical sixth through holes (603), and the second screw (8) is inserted into the sixth through holes (603); the third boss (602) is a cylindrical symmetrical structure; a cylindrical seventh through hole (604) is provided at the axial part of the third boss (602), and the first connecting rod (11) or the second connecting rod (12) is inserted into the seventh through hole (604), and the seventh through hole (604) also runs through the third body (601); a retaining frame, a ball and a retaining ring are also provided in the third boss (602); The first connecting rod (11) is a cylindrical symmetrical structure, the two ends of the first connecting rod (11) are inserted into the groove (901) of the support block (9), and the middle part of the first connecting rod (11) is inserted into the seventh through hole (604) of the linear bearing (6); The second connecting rod (12) is a cylindrical symmetrical structure, the two ends of the second connecting rod (12) are inserted into the groove (901) of the support block (9), and the middle part of the second connecting rod (12) is inserted into the seventh through hole (604) of the linear bearing (6).

2. The device for measuring the outer diameter of a rectangular steel pipe according to claim 1, characterized in that: The bottom plate (1) is a rectangular parallelepiped symmetrical structure, and the bottom plate (1) is symmetrically provided with four cylindrical first through holes (101), and the screw rods (13) are passed through the first through holes (101).

3. The device for measuring the outer diameter of a rectangular steel pipe according to claim 1, characterized in that: The first screw (3) is composed of a coaxial second body (301) and a second boss (302), the second body (301) and the second boss (302) are both cylindrical symmetrical structures, and the second boss (302) is located on the lower end surface of the second body (301); the end of the second boss (302) is provided with a thread for screwing into the fifth screw hole (903) of the support block (9); the upper end surface of the second body (301) is provided with a first rectangular through groove (303) for convenient screwing of the first screw (3).

4. The device for measuring the outer diameter of a rectangular steel pipe according to claim 1, characterized in that: The second screw (8) is composed of a coaxial fifth body (801) and a fifth boss (802), the fifth body (801) and the fifth boss (802) are both cylindrical symmetrical structures, and the fifth boss (802) is located on the right end surface of the fifth body (801); the end of the fifth boss (802) is provided with a thread for screwing into the third screw hole (704) of the second bracket (7); the left end surface of the fifth body (801) is provided with a second rectangular through groove (803) to facilitate screwing into the second screw (8).

5. The device for measuring the outer diameter of a rectangular steel pipe according to claim 1, characterized in that: The threaded end of the screw rod (13) is screwed with the nut (14).

6. The device for measuring the outer diameter of a rectangular steel pipe according to claim 1, characterized in that: The screw rod (13) and the nut (14) are both standard parts.

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