Clamp for testing plastic pipe

Abstract

The utility model relates to the technical field of pipe performance detection, in particular to a plastic pipe testing clamp which comprises a cup-shaped outer clamp and a conical inner clamp, the central axes of the cup-shaped outer clamp and the conical inner clamp coincide with each other, the peripheral wall of the cup-shaped outer clamp is matched with the outer peripheral wall of a to-be-tested plastic pipe, and the conical inner clamp is provided with a large-diameter end and a small-diameter end. The large-diameter end is close to the opening of the cup-shaped outer clamp, an elastic piece and a screw-in pressing piece are arranged between the small-diameter end and the cup-shaped outer clamp, the maximum diameter of the large-diameter end is smaller than the inner diameter of the plastic pipe to be measured, and a detachable connecting piece is further arranged at the end, away from the opening, of the cup-shaped outer clamp. According to the clamp for testing the plastic pipe, aiming at the maximum traction load test of the plastic pipe, the end part of the plastic pipe can be clamped and fixed through the cup-shaped outer clamp and the conical inner clamp, so that the phenomenon that a sample slips is not easy to occur, and the detection efficiency is improved.

Description

Technical Field

[0001] This application relates to the technical field of pipe performance testing, and particularly to a fixture for testing plastic pipes. Background Art

[0002] With the continuous advancement of urban underground pipe network construction, plastic pipes, as new building engineering materials, have been widely used in the field of underground space engineering. Due to construction conditions, most pipeline construction adopts trenchless construction methods, and pipelines are directly laid through the traction of equipment and facilities, which undoubtedly puts higher requirements on the pipeline traction load. However, there are also some problems in fully referring to the tensile property characterization methods of pipes, especially the maximum traction load performance. Currently, no method has been adopted as the standard method for the maximum traction load of pipes. Due to problems such as difficult clamping and slipping, the test results are difficult to interpret and reproduce.

[0003] Generally, tensile tests are mainly carried out using dumbbell-shaped or long-strip-shaped specimens. Due to the particularity of the maximum traction load of pipelines, the specimen clamping device is extremely prone to slipping, which cannot truly reflect the traction load of the material. Ordinary tensile test fixtures are not suitable for the maximum traction load tensile test of pipelines. Utility Model Content

[0004] This application provides a fixture for testing plastic pipes to improve the following technical problems:

[0005] Due to the particularity of the maximum traction load of pipelines, the specimen clamping device is extremely prone to slipping, which cannot truly reflect the traction load of the material. Ordinary tensile test fixtures are not suitable for the maximum traction load tensile test of pipelines.

[0006] This application provides a fixture for testing plastic pipes, adopting the following technical solutions:

[0007] A fixture for testing plastic pipes includes a cup-shaped outer fixture and a conical inner fixture with their central axes coinciding. The peripheral wall of the cup-shaped outer fixture is adapted to the outer peripheral wall of the plastic pipe to be tested. The conical inner fixture has a large-diameter end and a small-diameter end. The large-diameter end is adjacent to the opening of the cup-shaped outer fixture. An elastic member and a screw-in compression member are arranged between the small-diameter end and the cup-shaped outer fixture. The maximum diameter of the large-diameter end is smaller than the inner diameter of the plastic pipe to be tested. The elastic restoring force of the elastic member is used to drive the conical inner fixture to move towards the small-diameter end. When the screw-in compression member is tightened, the large-diameter end cooperates with the inner peripheral wall of the cup-shaped outer fixture to clamp and fix the plastic pipe to be tested. A detachable connecting member for connecting a tensile testing machine is further arranged at the end of the cup-shaped outer fixture far from the opening.

[0008] In an implementable technical solution of the present application, the precession pressing member includes a threaded rod and a screwing cap. A threaded hole is provided at the end of the cup-shaped outer fixture away from the opening. The threaded rod is threadedly assembled in the threaded hole. One end of the threaded rod is fixedly connected to the small-diameter end, and the screwing cap is provided at the other end of the threaded rod and is located outside the cup-shaped outer fixture.

[0009] In an implementable technical solution of the present application, the end of the threaded rod away from the screwing cap is inserted into the inside of the small-diameter end and fixedly connected by welding.

[0010] In an implementable technical solution of the present application, anti-slip lines are provided on the outer peripheral wall of the screwing cap.

[0011] In an implementable technical solution of the present application, the elastic member is a spring that is always in a stretched state. The threaded rod passes through the spring. One end of the spring is fixedly connected to the small-diameter end by welding, and the other end of the spring is fixedly connected to the inner bottom wall of the cup-shaped outer fixture.

[0012] In an implementable technical solution of the present application, there are multiple groups of detachable connectors, and the multiple groups of detachable connectors are symmetrically arranged at equal intervals around the central axis of the cup-shaped outer fixture.

[0013] In an implementable technical solution of the present application, the detachable connector includes a flange, a fixing bolt, a connecting rod, and a pin. The connecting rod is vertically connected to the flange. The flange is connected to the outer end face of the cup-shaped outer fixture by multiple groups of fixing bolts. A pin hole is provided on the connecting rod, and the pin is vertically inserted into the pin hole.

[0014] In an implementable technical solution of the present application, a pull ring is provided at one end of the pin.

[0015] In an implementable technical solution of the present application, the inner diameter at the opening of the cup-shaped outer fixture is 2 - 5 millimeters larger than the maximum outer diameter of the large-diameter end. The inner diameter at the opening of the cup-shaped outer fixture is between 40 - 50 millimeters, and the wall thickness of the cup-shaped outer fixture is between 25 - 35 millimeters.

[0016] In an implementable technical solution of the present application, both the cup-shaped outer fixture and the conical inner fixture are made of stainless steel, and the tensile strength is not less than 150 MPa.

[0017] In summary, the present application includes at least one of the following beneficial technical effects:

[0018] For the maximum traction load test of plastic pipes, the elastic member can initially move inward to temporarily clamp and fix the plastic pipe to be tested, and then further clamp and fix the end of the plastic pipe through the cup-shaped outer fixture and the conical inner fixture, so that the sample is not likely to slip, improving the detection efficiency. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic structural diagram of a fixture for testing plastic pipes in an embodiment of the present application.

[0021] Description of the Reference Numerals:

[0022] 1. Cup-shaped outer fixture;

[0023] 2. Conical inner fixture; 21. Larger diameter end; 22. Smaller diameter end;

[0024] 3. Elastic member;

[0025] 4. Screwing and pressing member; 41. Threaded rod; 42. Screwing cap;

[0026] 5. Detachable connecting member; 51. Flange; 52. Fixed bolt; 53. Connecting rod; 54. Pin; 541. Pulling ring. Detailed Embodiments

[0027] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clear, the following further details the present application in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0028] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0029] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0030] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0031] The following further elaborates on the present application in conjunction with the Figure 1 drawings.

[0032] An embodiment of the present application discloses a fixture for testing plastic pipes. Referring to Figure 1 , a fixture for testing plastic pipes includes a cup-shaped outer fixture 1 and a conical inner fixture 2 with coincident central axes. The peripheral wall of the cup-shaped outer fixture 1 is adapted to the outer peripheral wall of the plastic pipe to be tested. The conical inner fixture 2 has a large-diameter end 21 and a small-diameter end 22. The large-diameter end 21 is adjacent to the opening of the cup-shaped outer fixture 1. An elastic member 3 and a screw-in pressing member 4 are provided between the small-diameter end 22 and the cup-shaped outer fixture 1. The maximum diameter of the large-diameter end 21 is smaller than the inner diameter of the plastic pipe to be tested. The elastic restoring force of the elastic member 3 is used to drive the conical inner fixture 2 to move towards the small-diameter end 22. When the screw-in pressing member 4 is tightened, the large-diameter end 21 cooperates with the inner peripheral wall of the cup-shaped outer fixture 1 to clamp and fix the plastic pipe to be tested.

[0033] The screw-in pressing member 4 includes a threaded rod 41 and a screwing cap 42. A threaded hole is provided at the end of the cup-shaped outer fixture 1 away from the opening. The threaded rod 41 is threadedly assembled in the threaded hole. One end of the threaded rod 41 is fixedly connected to the small-diameter end 22. The screwing cap 42 is provided at the other end of the threaded rod 41 and is located outside the cup-shaped outer fixture 1. Moreover, the end of the threaded rod 41 away from the screwing cap 42 is inserted into the interior of the small-diameter end 22 and welded and fixed. Anti-slip grooves are provided on the outer peripheral wall of the screwing cap 42.

[0034] In this embodiment, the elastic member 3 is a spring that is always in a stretched state. The threaded rod 41 penetrates through the spring. One end of the spring is welded and fixed to the small-diameter end 22, and the other end of the spring is welded and fixed to the inner bottom wall of the cup-shaped outer fixture 1.

[0035] The elastic member 3 and the screw-in pressing member 4 designed above have simple and firm structures, long service lives, and relatively low manufacturing and installation costs.

[0036] In order to quickly connect and fix the fixture and the tensile testing machine, a detachable connecting member 5 for connecting the tensile testing machine is also provided at the end of the cup-shaped outer fixture 1 away from the opening. There are multiple groups of detachable connecting members 5, and the multiple groups of detachable connecting members 5 are symmetrically arranged at equal intervals around the central axis of the cup-shaped outer fixture 1.

[0037] Specifically, the detachable connecting member 5 includes a flange 51, fixing bolts 52, a connecting rod 53, and a pin 54. The connecting rod 53 is vertically connected to the flange 51. The flange 51 is connected to the outer end face of the cup-shaped outer fixture 1 through multiple groups of fixing bolts 52. A pin hole is provided on the connecting rod 53, and the pin 54 is vertically inserted into the pin hole.

[0038] At the same time, in order to facilitate the insertion and extraction of the pin 54, a pull ring 541 is provided at one end of the pin 54.

[0039] In this embodiment, the inner diameter of the opening of the cup-shaped outer fixture 1 is 2 - 5 millimeters larger than the maximum outer diameter of the large-diameter end 21. The inner diameter of the opening of the cup-shaped outer fixture 1 is between 40 - 50 millimeters, the wall thickness of the cup-shaped outer fixture 1 is between 25 - 35 millimeters. Both the cup-shaped outer fixture 1 and the conical inner fixture 2 are made of stainless steel, and the tensile strength is not less than 150 MPa.

[0040] The beneficial technical effects of a fixture for testing plastic pipes according to an embodiment of the present application are generally as follows:

[0041] For the maximum traction load test of plastic pipes, through the elastic member 3, inward movement can be initially achieved to temporarily clamp and fix the plastic pipe to be tested. Then, further clamp and fix the ends of the plastic pipe through the cup-shaped outer fixture 1 and the conical inner fixture 2. The phenomenon of specimen slippage is not likely to occur, and the detection efficiency is improved.

[0042] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the application shall be included within the protection scope of the present application.

Claims

1. A fixture for testing plastic pipes, characterized in that, It includes a cup-shaped outer fixture (1) and a conical inner fixture (2) with their central axes coinciding. The peripheral wall of the cup-shaped outer fixture (1) is adapted to the outer peripheral wall of the plastic pipe to be measured. The conical inner fixture (2) has a large-diameter end (21) and a small-diameter end (22). The large-diameter end (21) is adjacent to the opening of the cup-shaped outer fixture (1). An elastic member (3) and a screw-in pressing member (4) are provided between the small-diameter end (22) and the cup-shaped outer fixture (1). The maximum diameter of the large-diameter end (21) is smaller than the inner diameter of the plastic pipe to be measured. The elastic restoring force of the elastic member (3) is used to drive the conical inner fixture (2) to move towards the small-diameter end (22). When the screw-in pressing member (4) is tightened, the large-diameter end (21) cooperates with the inner peripheral wall of the cup-shaped outer fixture (1) to clamp and fix the plastic pipe to be measured. At the end of the cup-shaped outer fixture (1) far from the opening, a detachable connecting member (5) for connecting to a tensile testing machine is also provided.

2. The fixture for testing plastic pipes according to claim 1, wherein, The screw-in pressing member (4) includes a threaded rod (41) and a screwing cap (42). At the end of the cup-shaped outer fixture (1) far from the opening, a threaded hole is provided. The threaded rod (41) is threadedly assembled in the threaded hole. One end of the threaded rod (41) is fixedly connected to the small-diameter end (22), and the screwing cap (42) is arranged at the other end of the threaded rod (41) and is located outside the cup-shaped outer fixture (1).

3. The fixture for testing plastic pipes according to claim 2, characterized in that, The end of the threaded rod (41) far from the screwing cap (42) is inserted into the inside of the small-diameter end (22) and is welded and fixed.

4. The fixture for testing plastic pipes according to claim 2, characterized in that, Anti-slip patterns are provided on the outer peripheral wall of the screwing cap (42).

5. The fixture for testing plastic pipe according to claim 2, characterized in that, The elastic member (3) is a spring that is always in a stretched state. The threaded rod (41) passes through the spring. One end of the spring is welded and fixed to the small-diameter end (22), and the other end of the spring is welded and fixed to the inner bottom wall of the cup-shaped outer fixture (1).

6. The fixture for testing plastic pipes according to claim 1, wherein, There are multiple groups of the detachable connecting members (5), and the multiple groups of detachable connecting members (5) are evenly spaced and symmetrically arranged around the central axis of the cup-shaped outer fixture (1).

7. The fixture for testing plastic pipe according to claim 6, characterized in that, The detachable connecting member (5) includes a flange plate (51), fixing bolts (52), a connecting rod (53), and a pin (54). The connecting rod (53) is vertically connected to the flange plate (51). The flange plate (51) is connected to the outer end face of the cup-shaped outer fixture (1) by multiple groups of fixing bolts (52). A pin hole is provided on the connecting rod (53), and the pin (54) is vertically inserted into the pin hole.

8. A fixture for testing plastic pipes according to claim 7, characterized in that, A pull ring (541) is provided at one end of the pin (54).

9. A fixture for testing plastic pipes according to claim 1, characterized in that, The inner diameter of the opening of the cup-shaped outer fixture (1) is 2 - 5 mm larger than the maximum outer diameter of the large-diameter end (21). The inner diameter of the opening of the cup-shaped outer fixture (1) is between 40 - 50 mm, and the wall thickness of the cup-shaped outer fixture (1) is between 25 - 35 mm.

10. A fixture for testing plastic pipes according to claim 1, characterized in that, Both the cup-shaped outer fixture (1) and the conical inner fixture (2) are made of stainless steel, and their tensile strength is not less than 150 MPa.

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