Traceless pipe clamp with mechanical fixed-torque tightening function and fixed-torque tightening operation method thereof

Abstract

The present invention discloses a non-marking pipe clamp with a mechanical fixed-torque tightening function and a fixed-torque tightening operation method thereof, which belongs to the technical field of pipeline tools, and comprises a pipe clamp body, wherein the pipe clamp body comprises a clamping assembly, a driving assembly, a cam wrench and an anti-friction assembly, wherein one end of the driving assembly is arranged on the cam wrench, and the other end is arranged on the clamping assembly, and under the action of the cam wrench, the clamping assembly is used to push the clamping assembly to clamp the pipe fitting, and the clamping assembly is plug-in fixedly connected with a plurality of anti-friction assemblies, which are used for the clamping assembly to avoid damaging the surface of the circular pipe fitting and increase the friction between the clamping assembly and the surface of the circular pipe fitting when the pipe fitting is clamped, and the replacement of the anti-friction assemblies of different curvatures can adapt to pipe fittings of different calibers. The device has a simple structure, is easy to use, and is easy to disassemble and assemble, and has a piston body, which has a length adjustment function, and is used to deal with the outer diameter error of the pipe fitting and adjust the tightening and loosening torque of the pipe clamp, so as to better clamp the pipe fitting and realize the fixed-torque tightening of the pipe fitting.

Description

Technical Field

[0001] The patent of the present invention relates to a traceless pipe clamp with a mechanical fixed-torque tightening function and a fixed-torque tightening operation method thereof, and belongs to the technical field of pipeline tools. Background Art

[0002] The technology of pipe clamp tools is relatively mature. There are many kinds of adjustable wrench pipe clamps at home and abroad, which are basically composed of a clamp body, a handle, a movable jaw and its adjustment nut. Among them, the handle and the clamp body are an integral part, and sometimes a split structure connected by a pin. The inner surface of the front end of the clamp body (clamping the pipe fitting) has a row of teeth, which bite the steel pipe through its barbs. The barbs of the teeth on the rear end face bite the steel pipe with the same function as the teeth on the front end face; the rear handle is provided with threads, and the size of the jaws of the front and rear tooth surfaces of the clamp body can be adjusted by adjusting the nut to adapt to the outer diameter of steel pipes of different specifications. The traditional pipe clamp is a pipe clamp that damages the surface of the pipe fitting. In addition, the pipe clamp requires several adjustment nuts each time it is loosened or tightened, which is inconvenient to operate.

[0003] In order to solve the above problems, patent number CN201620683971.5 discloses a non-destructive pipe clamp ( Figure 1 ), including a force-bearing handle bar f, a connecting rod d, a first pipe clamp b, a second pipe clamp c, and a protective pad a; the head of the force-bearing handle bar f, the connecting rod d, the first pipe clamp b, and the second pipe clamp c are rotatably connected in sequence, and the free end of the second pipe clamp c is connected to the head of the force-bearing handle bar f by an openable and closable snap-on connection; one protective pad a is located on the inner side of the circular arc of the first pipe clamp b, and another protective pad a is located on the inner side of the circular arc of the second pipe clamp c. When the second pipe clamp c and the force-bearing handle bar f are buckled together, the first pipe clamp b and the second pipe clamp c hold the round pipe tightly to form a ring. Although this clamping method can achieve the purpose of protecting the outer surface of the pipeline during installation, there are still the following problems during use: first, in the natural state, the first pipe clamp and the second pipe clamp are separated from each other, occupying space and making it inconvenient to carry; second, due to the lack of the necessary clamping mechanism, note: this is the key, when in use, the force-bearing handle and the second pipe clamp are easily separated; third, the angle of the protective pads on the two pipe clamps of this scheme cannot be adjusted, which will cause the force-bearing area between the pipe clamp and the pipeline to be very small, and it is still easy to damage the epoxy resin surface outside the pipeline; third, the wear and deformation of the protective pads will easily increase the gap between the protective pads and the steel pipe, causing tightening slippage; finally, the oil stains on the surface of the steel pipe cause relative sliding between the pipe clamp and the steel pipe, resulting in tightening failure; in addition, the existing non-destructive pipe clamps do not have the mechanical fixed value control function of the pipe clamp force torque, which brings inconvenience to the popularization of the torque control method for pipeline threaded connections. Summary of the invention

[0004] The present invention aims at the technical problems mentioned in the above background technology and adopts the following technical solutions to achieve the above problems:

[0005] The markless pipe clamp with mechanical fixed-torque tightening function comprises a pipe clamp body, which comprises a clamping assembly, a driving assembly, a cam wrench and an anti-friction assembly. The shaft hole at one end of the driving assembly is connected to the cam wrench, and the other end is arranged on the clamping assembly. Under the action of the cam wrench, the clamping assembly is used to push the clamping assembly to clamp the pipe fitting. A plurality of anti-friction plates are inserted and fixedly connected to the clamping assembly to avoid damage to the surface of the circular pipe fitting when the clamping assembly clamps the pipe fitting and to increase the friction between the clamping assembly and the circular pipe fitting. Replacing the anti-friction assemblies with different curvatures can adapt to the tightening of pipe fittings of different calibers.

[0006] The clamping assembly comprises a lower clamping block, a concave lower clamping seat, a concave upper clamping block and a buckle; one end of the concave upper clamping block is hinged to one end of the concave lower clamping seat, the other end of the concave upper clamping block is hinged and locked with one end of the buckle, and the other end of the buckle is hinged to the other end of the concave lower clamping seat; the concave lower clamping seat, the concave upper clamping block and the buckle overlap to form a closed annular force-bearing structure; the lower clamping block is arranged on the concave lower clamping seat in the closed annular force-bearing structure, and is used for clamping the pipe fitting under the auxiliary push of the driving assembly; the lower clamping block and the concave upper clamping block are respectively provided with an upper anti-friction plate mounting groove and a lower anti-friction plate mounting groove;

[0007] The anti-friction assembly includes a lower anti-friction plate and an upper anti-friction plate. The upper anti-friction plate is installed in the upper anti-friction plate installation groove, and the lower anti-friction plate is installed in the lower anti-friction plate installation groove. By replacing different anti-friction assemblies, it can adapt to pipe fittings of different materials.

[0008] The anti-friction component is provided with one or more radian surfaces matching the radian of the clamped pipe fittings on the concave upper clamping block and the lower clamping block respectively.

[0009] The upper anti-friction plate and the lower anti-friction plate on the concave upper clamping block and the lower clamping block are respectively anti-friction plates of an integral structure.

[0010] The upper anti-friction plate and the lower anti-friction plate are both made of bakelite, and when used to clamp pipe fittings, they play an anti-static role.

[0011] A concave lower clamping seat central hole with an internal thread is provided in the center of the bottom of the concave lower clamping seat, and a lower clamping block central hole is provided in the center of the bottom of the lower clamping block. Bolts penetrate the central hole of the lower clamping block and the stepped central hole of the concave lower clamping seat and are connected with the central internal thread of the upper part of the split piston body in the driving assembly. The internal thread of the central hole at the bottom end of the concave lower clamping seat is connected with the external thread of the piston housing in the driving assembly. The lower clamping block moves to clamp the pipe fitting under the action of the piston body.

[0012] Furthermore, the central hole of the concave lower clamping seat is a cylindrical hole or a threaded hole, and the central hole of the lower clamping block is also a cylindrical hole or a threaded hole.

[0013] The driving assembly includes a piston body and a piston housing; the piston body is movably sleeved in the piston housing;

[0014] The piston body comprises a bolt, a spring, an upper part of the piston body, a lower part of the piston body, a shaft and a piston body roller; the diameter of the upper part of the piston body is smaller than the diameter of the lower part of the piston body, the outer thread at the lower end of the upper part of the piston body is connected with the inner thread of the lower part of the piston body, the spring is sleeved on the upper part of the piston body, one end of the spring is abutted against the upper end of the stepped central inner hole of the concave lower clamping seat, and the other end is abutted against the small round end of the lower part of the piston body, the bolt head is connected to the lower clamping block, the lower end of the bolt is connected to the inner thread of the upper part of the piston body through a thread, the lower part of the piston body is provided with an axial hole and an open groove, and the axial hole of the piston body is connected with the open groove of the piston body, the piston body roller is connected to the shaft, and the shaft is connected to the axial hole of the piston body;

[0015] The piston housing comprises an external thread of the piston housing, a waist groove of the mounting hole, a camshaft hole and an opening groove, and the waist groove of the mounting hole and the camshaft hole are connected with the opening groove of the piston housing;

[0016] The piston body is movably sleeved in the piston housing through the piston body shaft and the waist-shaped groove of the mounting hole on the piston housing.

[0017] The cam body wrench has a cam body at one end and a wrench at the other end; the cam body is provided with a cam surface, a camshaft hole, a bearing and a camshaft; the cam body wrench is sleeved in the camshaft hole on the piston housing through the camshaft hole, the bearing and the camshaft; the cam surface at one end of the cam body abuts against the piston body roller;

[0018] The piston body roller is rotatably sleeved on the piston body shaft, and the piston body shaft is sleeved in the waist-shaped groove of the mounting hole on the piston shell. When the piston body reciprocates under the push of the cam body wrench, the lower clamping block moves to clamp or loosen the pipe fitting under the action of the piston body.

[0019] Furthermore, the first rotating sleeve is a bearing or a sleeve ring.

[0020] The offset distance of the cam curved surface at the cam body end is 1 mm to 10 mm, and the other end of the cam body wrench is set as a force application handle wrench.

[0021] The offset of the cam surface at the cam body end is preferably 2 mm to 3 mm.

[0022] According to the above-mentioned fixed-torque tightening operation method proposed by the traceless pipe pliers with mechanical fixed-torque tightening function, the torque force of the cam wrench is transmitted to the external thread of the pipe fitting by clamping the pipe fitting body through the clamping assembly to generate a rotational tightening force; the main steps are: changing the length of the piston body by adjusting the screwing length between the upper part of the piston body and the lower part of the piston body, thereby adjusting the clamping force, and after the clamping force is adjusted, its maximum clamping force is certain; when the torque force of the cam wrench continues to increase externally and the pipe fitting cannot be tightened any further, slippage or detwisting will occur between the clamping assembly and the pipe fitting, thereby achieving mechanical fixed-torque tightening of the pipe fitting by adjusting the screwing length.

[0023] The beneficial effects of the present invention are as follows: the device has a simple structure, is easy to use, and is easy to disassemble and assemble. An anti-friction component is arranged in the clamping component. Moreover, the auxiliary drive of the cam on the driving component makes it difficult for the outer surface of the clamped pipe to slip. In addition, the device also has a piston body (the piston body can adjust its own length through the threaded connection relationship between the upper part of the piston body and the lower part of the piston body, thereby achieving the effect of piston stroke adjustment, and the distance between the two ends of the piston body can be fine-tuned by rotating the upper part of the piston body or the lower part of the piston body), which is used to adjust the outer diameter error of the pipe, so that It can better clamp the pipe fittings; more importantly, the length of the piston body is changed by adjusting the screwing length between the upper part of the piston body and the lower part of the piston body, that is, the piston working stroke is changed, thereby adjusting the force value of the pipe fitting being clamped; after the clamping force is adjusted, its maximum clamping force (or friction force) is certain; when the torque force of the cam wrench continues to increase outside and the pipe fitting cannot be tightened further, the friction force between the clamping assembly and the pipe fitting cannot withstand the torque force of the cam wrench, and the two will slip or twist off, thereby realizing mechanical fixed torque tightening of the pipe fitting. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a prior art diagram;

[0025] Figure 2 It is a structural schematic diagram of the present invention;

[0026] Figure 3 A top view of the present invention;

[0027] Figure 4 is a schematic structural diagram of the second anti-friction plate of the present invention;

[0028] Figure 5 It is a vertical cross-sectional view of the present invention;

[0029] Figure 6 for Figure 5 The structural diagram of part A in the figure;

[0030] Figure 7 An exploded view of the present invention;

[0031] Figure 8 Schematic diagram of the connection relationship between the upper part and the lower part of the piston body of the present invention

[0032] Fig. 9 It is a force diagram of the fixed-torque tightening operation of the present invention.

[0033] In the figure: 1-clamping assembly, 11-lower clamping block, 111-central hole of lower clamping block, 112-lower (clamping block) anti-friction plate mounting groove, 12-concave lower clamping seat, 121-central hole of concave lower clamping seat with internal thread, 1211-inner thread of central hole at bottom end of concave lower clamping seat, 13-concave upper clamping block, 131-upper anti-friction plate mounting groove, 14-buckle, 141-buckle spring, 2-driving assembly, 21-piston body, 211-bolt, 212-spring, 2131-upper part of piston, 21311-inner thread of upper part of piston, 2132- The lower part of the piston, 2133-axis hole, 2134-opening groove, 214-axis, 215-piston body roller, 22-piston housing, 221-piston housing external thread, 222-mounting hole waist groove, 223-camshaft hole, 224-opening groove, 3-cam body wrench, 31-cam body, 311-cam surface, 312-camshaft hole, 313-cam bearing, 314-camshaft, 32-wrench, 4-anti-friction assembly, 41-lower anti-friction plate, 42-upper anti-friction plate, 5-clamping force, 6-resistance to be overcome for tightening the pipe fitting, 7-pipe fitting. DETAILED DESCRIPTION

[0034] In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the patent of the present invention is further explained below with reference to specific diagrams.

[0035] like Figure 1 It is the prior art. Firstly, the pipe clamp occupies space in its natural state and is inconvenient to carry. Secondly, when in use, the force-bearing handle f is easily separated from the second pipe clamp c. Thirdly, the angle of the protective pad a on the first pipe clamp b and the second pipe clamp c of the scheme cannot be adjusted, which will cause the force-bearing area between the first pipe clamp b and the second pipe clamp c and the pipeline to be very small, and it is still easy to damage the epoxy resin surface outside the pipeline. In addition, the wear and deformation of the protective pad a will easily increase the gap between the protective pad a and the steel pipe, resulting in slippage during tightening. The oil stains on the surface of the steel pipe cause relative sliding between the pipe clamp and the steel pipe, resulting in tightening failure. Obviously, this technical solution cannot achieve mechanical fixed torque control to tighten the pipe clamp.

[0036] like Figure 2-9As shown, a traceless pipe clamp with a mechanical fixed-torque tightening function and a fixed-torque tightening operation method thereof include a pipe clamp body, the pipe clamp body including a clamping assembly 1, a driving assembly 2, a cam body wrench 3 and an anti-friction assembly 4. The axial hole at one end of the driving assembly 2 is connected to the cam body wrench 3, and the other end is arranged on the clamping assembly 1. Under the action of the cam body wrench 3, it is used to push the clamping assembly 1 to clamp the pipe fitting. A plurality of anti-friction assemblies 4 are inserted and fixedly connected to the clamping assembly 1, which are used to avoid damaging the surface of the circular pipe fitting when the clamping assembly 1 is clamping the pipe fitting and increase the friction between the clamping assembly 1 and the circular pipe fitting. Replacing anti-friction assemblies with different curvatures can adapt to the tightening of pipe fittings of different calibers.

[0037] The clamping assembly 1 comprises a lower clamping block 11, a concave lower clamping seat 12, a concave upper clamping block 13 and a buckle 14; one end of the concave upper clamping block 13 is hinged to one end of the concave lower clamping seat 12, the other end of the concave upper clamping block 13 is hinged and locked with one end of the buckle 14, and the other end of the buckle 14 is hinged to the other end of the concave lower clamping seat 12; the concave lower clamping seat 12, the concave upper clamping block 13 and the buckle 14 overlap to form a closed annular force-bearing structure; the lower clamping block 11 is arranged on the concave lower clamping seat 12 in the closed annular force-bearing structure, and is used for clamping the pipe fitting under the auxiliary push of the driving assembly 2; the lower clamping block 11 and the concave upper clamping block 13 are respectively provided with an upper anti-friction plate mounting groove 131 and a lower anti-friction plate mounting groove 112;

[0038] The anti-friction component 4 includes a lower anti-friction plate 41 and an upper anti-friction plate 42. The upper anti-friction plate 42 is installed in the upper anti-friction plate installation groove 131, and the lower anti-friction plate 41 is installed in the lower anti-friction plate installation groove 112. By replacing different anti-friction components, it can adapt to pipes of different materials.

[0039] Furthermore, the buckle 14 is sleeved with a buckle spring 141 for driving the buckle 14 to fasten or loosen the whole formed by the lower clamping block 11 , the concave lower clamping seat 12 , and the concave upper clamping block 13 .

[0040] The anti-friction component 4 is provided with one or more cambered surfaces matching the camber of the clamped pipe fitting on the concave upper clamping block 13 and the lower clamping block 11 respectively.

[0041] The upper anti-friction plate 42 and the lower anti-friction plate 41 on the concave upper clamping block 13 and the lower clamping block 11 are respectively anti-friction plates of an integral structure.

[0042] The upper anti-friction sheet 42 and the lower anti-friction sheet 41 are both made of bakelite, and when used to clamp pipe fittings, they play an anti-static role.

[0043] A concave lower clamping seat central hole 121 with an internal thread is provided in the center of the bottom of the concave lower clamping seat 12, and a lower clamping block central hole 111 is provided in the center of the bottom of the lower clamping block 11. A bolt 211 penetrates the lower clamping block central hole 111 and the concave lower clamping seat stepped central hole 121 and is connected to the central internal thread 21311 of the upper part of the split piston body in the drive assembly 2. The internal thread 1211 of the central hole at the bottom end of the concave lower clamping seat is connected to the external thread 221 of the piston housing in the drive assembly 2, and the lower clamping block 11 moves to clamp the pipe fitting under the action of the piston body 21.

[0044] The driving assembly 2 includes a piston body 21 and a piston housing 22; the piston body 21 is movably mounted in the piston housing 22;

[0045] The piston body 21 includes a bolt 211, a spring 212, an upper part 2131 of the piston body, a lower part 2132 of the piston body, a shaft 214 and a piston body roller 215; the diameter of the upper part 2131 of the piston body is smaller than the diameter of the lower part 2132 of the piston body, the outer thread at the lower end of the upper part 2131 of the piston body is connected with the inner thread of the lower part 2132 of the piston body, the spring 212 is sleeved on the upper part of the piston body, and one end of the spring 212 is against the upper end of the stepped central inner hole of the concave lower clamping seat 12 , the other end is butted against the small round end of the lower part 2132 of the piston body, the head of the bolt 211 is connected to the lower clamping block 11, the lower end of the bolt 211 is connected to the internal thread 21311 of the upper part of the piston body through a thread, the lower part 2132 of the piston body is provided with an axial hole 2133 and an opening groove 2134, and the axial hole 2133 of the piston body is communicated with the opening groove 2134 of the piston body, the piston body roller 215 is connected to the shaft 214, and the shaft 214 is connected to the axial hole 2133 of the piston body;

[0046] The piston housing 22 includes a piston housing external thread 221, a mounting hole waist groove 222, a camshaft hole 223 and an opening groove 224, and the mounting hole waist groove 222 and the camshaft hole 223 are connected to the piston housing opening groove 224;

[0047] The piston body 21 is movably mounted in the piston housing 22 through the piston body shaft 214 and the waist-shaped groove 222 of the mounting hole on the piston housing 22 .

[0048] One end of the cam wrench 3 is a cam body 31, and the other end is a wrench 32; the cam body 31 is provided with a cam surface 311, a camshaft hole 312, a bearing 313 and a camshaft 314, and the cam body wrench is sleeved in the camshaft hole 223 on the piston housing 22 through the camshaft hole 312, the bearing 313 and the camshaft 314, and the cam surface 311 at one end of the cam body 31 abuts against the piston body roller 215;

[0049] The piston body roller 215 is rotatably sleeved on the piston body shaft 214, and the piston body shaft 214 is sleeved in the waist-shaped groove 222 of the mounting hole on the piston housing 22. When the piston body 21 reciprocates under the push of the cam body wrench 3, the lower clamping block 11 moves to clamp or loosen the pipe fitting under the action of the piston body 21.

[0050] The offset of the cam surface at the end of the cam body 31 is 1 mm to 10 mm, and the other end of the cam body wrench 3 is set as a force wrench 32.

[0051] The offset of the cam surface at the end of the cam body 31 is preferably 2 mm to 3 mm.

[0052] The operating steps when using the wrench are as follows:

[0053] I. According to the tightening torque required for tightening different pipe fittings, adjust the torque value of the mechanical untwisting pipe clamp wrench. The specific method is: unscrew the bolt 211, remove the lower clamping block 11, use a flat-blade screwdriver to screw out or screw in the upper part of the piston body to fix the actual clamping stroke of the piston, install the lower clamping block 11, and tighten the bolt 211;

[0054] II. Select a matching anti-friction plate according to the diameter of the pipe to be clamped and install it in the concave upper clamping block anti-friction plate mounting groove 131 and the lower clamping block anti-friction plate mounting groove 112;

[0055] III. Open the buckle 14, put the concave upper clamping block 13 on the clamping assembly on the pipe, and then lock it with the buckle 14, clamp the pipe between the concave upper clamping block 13 and the lower clamping block 11, and during the clamping process, the upper anti-friction plate 42 contacts one side of the pipe;

[0056] IV. Apply tightening force to the cam wrench 3. The cam surface 311 pries the piston body roller 215 under the external force of the cam wrench 3, overcomes the spring 212 and pushes the piston lower part 2132. The cam surface 311 and the piston lower part 2132 drive the rigidly connected lower clamping block 11 to first tighten the pipe clamped by the lower anti-friction plate 41 and the upper anti-friction plate 42, and then drive the pipe to rotate a certain angle (e.g., 60 degrees);

[0057] V. With the assistance of the spring 212, when the cam surface 311 returns to the starting position from the offset, the piston lower part 2132 returns to the original position, and the cam body wrench 3 is rotated to perform the next tightening stroke until the pipe fitting is completely tightened. During the horizontal reciprocating motion of the piston lower part 2132, the shaft 214 connected to the piston body roller 215 reciprocates inside the waist groove 222 of the mounting hole;

[0058] VI. When the pipe fitting is to be loosened, the cam body wrench 3 is rotated in the opposite direction, and the cam surface 311 is used to pry the piston body roller 215 under the external force of the cam body wrench 3, thereby overcoming the spring 212 to push the piston lower part 2132. The piston lower part 2132 drives the rigidly connected lower clamping block 11, firstly tightens the pipe fitting clamped by the lower anti-friction plate 41 and the upper anti-friction plate 42, and then drives the pipe fitting to rotate in the opposite direction by a certain angle (such as 60 degrees). With the assistance of the spring 212, when the cam surface 311 returns to the starting position from the offset, the piston lower part 2132 returns to the original position. In this way, the cam body wrench 3 is rotated again to perform the next loosening stroke until the pipe fitting is completely loosened.

[0059] The principle of the fixed-torque tightening operation is as follows: the torque force of the cam wrench 3 is transmitted to the external thread of the pipe fitting 7 through the clamping assembly 1 to clamp the pipe fitting 7 body and generate a rotational tightening force; the main steps are: changing the length of the piston body 21 by adjusting the screwing length between the upper part 2131 of the piston body and the lower part 2132 of the piston body, thereby adjusting the clamping force 5. After the clamping force 5 is adjusted, its maximum clamping force is certain; when the torque force of the cam wrench 3 continues to increase from the outside and the pipe fitting cannot be tightened any further, slippage or untwisting will occur between the clamping assembly 1 and the pipe fitting 7, thereby achieving mechanical fixed-torque tightening of the pipe fitting by adjusting the screwing length.

[0060] The above shows and describes the basic principle and main features of the present invention and the advantages of the present invention. The technicians in this industry should understand that the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements. For example, the wrench cam bearing 313 may use a roller structure instead of a bearing structure, and the anti-friction component 4 may use other anti-friction and anti-static materials instead of bakelite, etc. These changes and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A non-marking pipe clamp with a mechanical fixed-torque tightening function, comprising a pipe clamp body, characterized in that: The pipe clamp body comprises a clamping assembly (1), a driving assembly (2), a cam wrench (3) and an anti-friction assembly (4); one end of the driving assembly (2) is connected to the cam wrench (3) through an axial hole, and the other end is arranged on the clamping assembly (1). Under the action of the cam wrench (3), the clamping assembly (1) is used to push the clamping assembly (1) to clamp the pipe fitting; a plurality of anti-friction assemblies (4) are inserted and fixedly connected to the clamping assembly (1) to avoid damaging the surface of the circular pipe fitting when the clamping assembly (1) clamps the pipe fitting and to increase the friction between the clamping assembly (1) and the circular pipe fitting; replacement of anti-friction assemblies with different curvatures can adapt to the tightening of pipe fittings with different calibers; The driving assembly (2) comprises a piston body (21) and a piston housing (22); the piston body (21) is movably mounted in the piston housing (22); The piston body (21) comprises a bolt (211), a spring (212), an upper part of the piston body (2131), a lower part of the piston body (2132), a shaft (214) and a piston body roller (215); the diameter of the upper part of the piston body (2131) is smaller than the diameter of the lower part of the piston body (2132); the outer thread at the lower end of the upper part of the piston body (2131) is connected to the inner thread of the lower part of the piston body (2132); the spring (212) is sleeved on the upper part of the piston body, one end of which is against the upper end of the stepped central inner hole of the concave lower clamping seat (12), and the other end of which is against the upper end of the stepped central inner hole of the concave lower clamping seat (12). The end of the bolt (211) abuts against the small round end of the lower part (2132) of the piston body, the head of the bolt (211) is connected to the lower clamping block (11), the lower end of the bolt (211) is connected to the internal thread (21311) of the upper part of the piston body through a thread, the lower part (2132) of the piston body is provided with an axial hole (2133) and an opening groove (2134), and the axial hole (2133) of the piston body is connected to the opening groove (2134) of the piston body, the piston body roller (215) is connected to the shaft (214), and the shaft (214) is connected to the axial hole (2133) of the piston body; The piston housing (22) comprises a piston housing external thread (221), a mounting hole waist groove (222), a camshaft hole (223) and an opening groove (224), and the mounting hole waist groove (222) and the camshaft hole (223) are in communication with the piston housing opening groove (224); The piston body (21) is movably mounted in the piston housing (22) through the piston body shaft (214) and then through the mounting hole waist groove (222) on the piston housing (22).

2. The traceless pipe clamp with mechanical torque tightening function according to claim 1, characterized in that: The clamping assembly (1) comprises a lower clamping block (11), a concave lower clamping seat (12), a concave upper clamping block (13) and a buckle (14); one end of the concave upper clamping block (13) is hinged to one end of the concave lower clamping seat (12), the other end of the concave upper clamping block (13) is hinged and locked to one end of the buckle (14), and the other end of the buckle (14) is hinged to the other end of the concave lower clamping seat (12); the concave lower clamping seat ( 12) overlaps with the concave upper clamping block (13) and the buckle (14) to form a closed annular force-bearing structure; the lower clamping block (11) is arranged on the concave lower clamping seat (12) in the closed annular force-bearing structure, and is used to clamp the pipe fitting under the auxiliary push of the driving component (2); the lower clamping block (11) and the concave upper clamping block (13) are respectively provided with an upper anti-friction plate installation groove (131) and a lower anti-friction plate installation groove (112); The anti-friction component (4) comprises a lower anti-friction plate (41) and an upper anti-friction plate (42); the upper anti-friction plate (42) is installed in the upper anti-friction plate installation groove (131), and the lower anti-friction plate (41) is installed in the lower anti-friction plate installation groove (112); and by replacing different anti-friction components, it can adapt to pipe fittings of different materials.

3. The traceless pipe clamp with mechanical torque tightening function according to claim 2, characterized in that: The anti-friction component (4) is provided with one or more cambered surfaces matching the camber of the clamped pipe fitting on the concave upper clamping block (13) and the lower clamping block (11).

4. The traceless pipe clamp with mechanical torque tightening function according to claim 3, characterized in that: The upper anti-friction plate (42) and the lower anti-friction plate (41) on the concave upper clamping block (13) and the lower clamping block (11) are respectively anti-friction plates of an integral structure.

5. The traceless pipe clamp with mechanical torque tightening function according to claim 2, characterized in that: A concave lower clamping seat central hole (121) with an internal thread is provided at the center of the bottom of the concave lower clamping seat (12); a lower clamping block central hole (111) is provided at the center of the bottom of the lower clamping block (111); a bolt (211) penetrates the lower clamping block central hole (111) and the concave lower clamping seat stepped central hole (121) and is connected to the central internal thread (21311) of the upper part of the split piston body in the driving component (2); the internal thread (1211) of the central hole at the bottom end of the concave lower clamping seat is connected to the external thread (221) of the piston shell in the driving component (2); the lower clamping block (11) moves to clamp the pipe fitting under the action of the piston body (21).

6. The traceless pipe clamp with mechanical torque tightening function according to claim 1, characterized in that: One end of the cam body wrench (3) is a cam body (31), and the other end is a wrench (32); the cam body (31) is provided with a cam curved surface (311), a cam shaft hole (312), a bearing (313) and a cam shaft (314); the cam body wrench is sleeved into a cam shaft hole (223) on a piston housing (22) through the cam shaft hole (312), the bearing (313) and the cam shaft (314); the cam curved surface (311) at one end of the cam body (31) abuts against the piston body roller (215); The piston body roller (215) is rotatably sleeved on the piston body shaft (214), and the piston body shaft (214) is sleeved in the waist-shaped groove (222) of the mounting hole on the piston housing (22). When the piston body (21) is pushed by the cam body wrench (3) to make reciprocating motion, the lower clamping block (11) moves to clamp or loosen the pipe fitting under the action of the piston body (21).

7. The traceless pipe clamp with mechanical torque tightening function according to claim 6, characterized in that: The offset distance of the cam curved surface at the end of the cam body (31) is 1 mm to 10 mm, and the other end of the cam body wrench (3) is configured as a force wrench (32).

8. The traceless pipe clamp with mechanical torque tightening function according to claim 7, characterized in that: The offset distance of the cam surface at the end of the cam body (31) is preferably 2 mm to 3 mm.

9. The method for tightening the fixed torque provided by the traceless pipe clamp with mechanical fixed torque tightening function according to any one of claims 1 to 8, characterized in that: The torque force of the cam wrench (3) is transmitted to the external thread of the pipe fitting (7) through the clamping assembly (1) to clamp the pipe fitting (7) body and generate a rotational tightening force; The main steps are: changing the length of the piston body (21) by adjusting the screwing length between the upper part (2131) of the piston body and the lower part (2132) of the piston body, thereby adjusting the clamping force (5); after the clamping force (5) is adjusted, its maximum clamping force is certain; when the torque force of the cam wrench (3) is continuously increased externally and the pipe fitting cannot be tightened any further, slippage or untwisting will occur between the clamping assembly (1) and the pipe fitting (7), thereby achieving mechanical fixed torque tightening of the pipe fitting by adjusting the screwing length.

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