CN212483153U

CN212483153U - Clamp for fatigue tensile test of steel strand

Info

Publication number: CN212483153U
Application number: CN202021434334.7U
Authority: CN
Inventors: 丁炳楠; 胡忠雯; 彭卫; 查支祥; 沈轲; 方思泽
Original assignee: Zhejiang University of Science and Technology ZUST
Current assignee: Ningbo University of Technology; Zhejiang University of Science and Technology ZUST
Priority date: 2020-07-20
Filing date: 2020-07-20
Publication date: 2021-02-05
Anticipated expiration: 2030-07-20

Abstract

The utility model discloses a fixture for steel strand fatigue tensile test, including the urceolus, the urceolus is close to the one end of steel strand wires and has first internal thread, there is first external screw thread on a compression sleeve, the centre bore of compression sleeve is for being close to the conical hole that one end of steel strand wires is little, the one end of keeping away from the steel strand wires is big, there is a centre bore in the conical hole for the cylindric hole that registrates with one end of steel strand wires, the excircle is the conical lock sleeve that matches with this conical hole, there are a plurality of axially extended openings on the at least major part end of lock sleeve, the first internal thread on compression sleeve and the urceolus are rotatory and are locked the steel strand wires of this end through the lock sleeve; and a second internal thread is arranged at one end of the outer barrel, which is far away from the steel strand, the second external thread of an axial abutting column is screwed with the second internal thread, and the inner end surface of the axial abutting column abuts against the inner end surfaces of the locking sleeve and the pressing sleeve. All parts of the clamp can be timely abutted tightly to eliminate mutual axial gaps and are easy to assemble or disassemble.

Description

Clamp for fatigue tensile test of steel strand

Technical Field

The utility model relates to a metal fatigue resistance test equipment technical field specifically says to an anchor clamps that steel strand wires fatigue tensile test used.

Background

The application of the steel strand in the buildings such as bridges, large-scale venues and the like is more and more extensive. The steel strand is generally applied to the occasion of prestress stretching, and the phenomenon of sudden fracture exists in the condition that the working stress is smaller than the yield strength after a certain number of cycles in practical use, and the phenomenon is generally called fatigue fracture. Therefore, fatigue resistance tests must be performed before the steel strand is applied to improve durability and safety of its use.

The prior art steel strand fatigue tensile test or steel strand axial stress fatigue test is carried out on a metal fatigue testing machine. And cutting off the steel strand with a certain length, clamping two ends of the steel strand by using a clamp for the fatigue tensile test of the steel strand, and connecting the clamp with a metal fatigue testing machine through a connecting device. The clamps are used in pairs.

The clamp structure that prior art's steel strand wires fatigue tensile test used is different, nevertheless all pays close attention to on the clamp force of anchor clamps to the steel strand wires, prevents that anchor clamps from to the centre gripping damage of steel strand wires clamping department, but prior art's clamp that steel strand wires fatigue tensile test used still exists following not enoughly: 1. due to frequent axial vibration and the axial rebound effect of the steel strand, gaps are easy to appear between the end parts of the steel strand clamping component and the end parts of other components in the mutually offset clamp due to abrasion, so that the accuracy of the fatigue tensile test is reduced, and even the failure of the fatigue tensile test is caused. 2. When the clearance increases to a certain extent, the entire jig must be replaced, increasing the material cost and the labor cost for machining. 3. The shape and structure of the clamp are complex, the processing is difficult, and the assembling and disassembling process is time-consuming and labor-consuming.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide a steel strand wires fatigue tensile test uses anchor clamps that can support tightly in good time between each part in order to eliminate mutual axial gap and easily assemble or dismantle.

The technical solution of the utility model is that, a fixture for steel strand fatigue tensile test is provided, including the urceolus, there is first internal thread in the center hole of the urceolus near the one end of steel strand, there is first external screw thread on a compression sleeve, the center hole of compression sleeve is the conical hole that one end that is close to the steel strand is little, the one end that keeps away from the steel strand is big, there is a center hole in the conical hole for the cylindrical hole that registrates with steel strand one end, the excircle is the conical lock sleeve that matches with this conical hole, there are a plurality of axially extended openings on the at least major part end of lock sleeve, the first external screw thread on the compression sleeve with the first internal thread on the urceolus revolve and lock the steel strand of this end through the lock sleeve; and a second internal thread is arranged in a central hole at one end of the outer barrel, which is far away from the steel strand, the second external thread of an axial abutting column is screwed with the second internal thread, the inner end face of the axial abutting column is abutted with the inner end faces of the locking sleeve and the pressing sleeve, and the outer end of the axial abutting column is a screwing force application end.

After the structure above adopting, the utility model discloses anchor clamps that steel strand wires fatigue tensile test used have following advantage: in the process of the fatigue tensile test of the steel strand, even if frequent axial vibration and axial rebound action of the steel strand exist, the axial abutting column can be screwed in time, the inner end face of the axial abutting column abuts against the inner end face of the locking sleeve and the inner end face of the compression sleeve and can also abut against the end face of the tested steel strand, possible abrasion is compensated in time, gaps among the inner end face of the axial abutting column, the inner end face of the locking sleeve and the inner end face of the compression sleeve are basically eliminated, the accuracy of the fatigue tensile test is greatly improved, and the accuracy and the success rate of the fatigue tensile test are effectively guaranteed. Through long-time wearing and tearing, even need change new, also only need change the axial and support tight post a part can, need not change whole anchor clamps, reduced the material cost and the human cost of processing by a wide margin. The clamp parts are regular in shape, either conical or circular, and can be sleeved inside and outside or screwed inside and outside, the structure is simple and reliable, the processing is easy, the assembling and disassembling processes are time-saving and labor-saving, and the production, assembly and disassembly efficiency is high.

Furthermore, the outer cylinder, the pressing sleeve, the locking sleeve and the axial abutting column are all made of steel. By adopting the structure, the clamp has the advantages of good strength, high hardness, large clamping force on the steel strand and good clamping effect.

Furthermore, the central hole of the outer cylinder is a step hole, the diameter of the end close to the steel strand is large, the first internal thread is arranged in the large-diameter hole of the step hole, and the diameter of the end of the step hole provided with the second internal thread is small; the compressing sleeve is a step sleeve, and the first external thread is arranged on the small-diameter sleeve of the step sleeve. Structure more than adopting, it is spacing to compress tightly between cover and the urceolus axial, and more even to the radial application of force of conical lock sleeve, the oppression effect is better, makes conical lock sleeve more even to the application of force of steel strand wires, and the locking effect is better, and the locking dynamics is higher, and the locking reliability is stronger.

Furthermore, the outer cylinder is provided with a radial threaded hole for preventing the pressing sleeve from rotating relative to the outer cylinder and a radial threaded pin which is screwed in the radial threaded hole and abuts against the pressing sleeve. After the structure is adopted, the pressing sleeve is prevented from rotating relative to the outer cylinder in the circumferential direction, so that the loosening of the pressing sleeve is avoided, and the pressing reliability of the pressing sleeve on the locking sleeve and the locking reliability of the locking sleeve on the steel strand are further ensured.

Furthermore, the axial abutting column is a step column, the second external thread is arranged on the large-diameter column of the step column, and the small-diameter column of the step column is a screwing force application end. After the structure is adopted, materials are saved relatively, and a position is provided for mounting a pressure spring.

Furthermore, a pressure spring is sleeved on the small-diameter column, the pressure spring is accommodated in a first annular groove between the small-diameter column and the central hole at the end of the outer cylinder, the inner end of the pressure spring abuts against the outer end face of the large-diameter column, and the outer end of the pressure spring abuts against the inner end face of a pressure ring which is fastened on the end face of the outer cylinder through a bolt. After the structure is adopted, as the pressure spring is always in a state of abutting against the axial abutting column, as long as the axial abutting column is screwed, namely, as long as the inner end surface of the axial abutting column abuts against the inner end surface of the locking sleeve and the inner end surface of the pressing sleeve or the inner end surface of the steel strand, the circumferential rotation of the axial abutting column is automatically limited by the elasticity of the pressure spring without manually loosening or screwing the locking pin and the like, the axial abutting column is automatically prevented from rotating relative to the outer sleeve in the circumferential direction, namely, the axial abutting column is prevented from loosening, the abutting reliability of the axial abutting column is further ensured, the inner end surface of the axial abutting column is further ensured to always abut against the inner end surface of the locking sleeve, the inner end surface of the pressing sleeve and the inner end surface of the steel strand, the gaps among the inner end surface of the axial abutting column, the inner end surface of the locking sleeve, the inner end surface of the pressing sleeve and the inner end surface of the steel strand are further, further ensuring the accuracy and success rate of the fatigue tensile test.

Furthermore, the hole wall of the cylindrical hole of the locking sleeve is provided with an annular bulge or a copper sleeve or an aluminum sleeve. After the structure is adopted, the annular protrusion and the steel strand have certain engaging force, and the copper sleeve or the aluminum sleeve and the steel strand have certain embedding force, so that the clamping force of the locking sleeve on the steel strand is further ensured, the accuracy of a fatigue tensile test is further improved, and the accuracy and the success rate of the fatigue tensile test are further ensured.

Furthermore, a second annular groove is formed in the outer wall of the large head end of the locking sleeve, and an elastic hoop is arranged in the second annular groove. After adopting above structure, the installation and the dismantlement of the conical lock sleeve of being convenient for.

Furthermore, the plurality of axially extending openings penetrate through two ends of the locking sleeve, so that a plurality of locking sheets are formed, and the plurality of locking sheets are hooped at one end of the steel strand by the elastic hoop to form the conical locking sleeve. After the structure is adopted, another specific embodiment of the conical locking sleeve is provided, and the locking sleeve has relatively large gripping allowance to the steel strand and stronger locking force due to the adoption of a plurality of locking sheets.

Furthermore, the clamps for clamping the two ends of the tested steel strand are symmetrically arranged, and the clamps at the two ends are the same in shape, structure and size and opposite in direction. After adopting above structure, the manufacturing, keeping, the installation of anchor clamps are more convenient, and is more laborsaving, and it is more convenient to operate during the fatigue tensile test of reality.

Drawings

Fig. 1 is a schematic view of a three-dimensional structure of an embodiment of the clamp of the present invention, which is symmetrically arranged at two ends and connected with a tested steel strand when performing a fatigue tensile test.

Fig. 2 is an enlarged schematic view of a in fig. 1.

Fig. 3 is a first schematic diagram of a longitudinal cross-sectional structure of an embodiment of the clamp of the present invention, which is symmetrically disposed at both ends and connected to a steel strand to be tested when performing a fatigue tensile test.

Fig. 4 is an enlarged structural diagram of B in fig. 3.

Fig. 5 is a schematic diagram of a longitudinal sectional structure of an embodiment of the clamp of the present invention, which is symmetrically disposed at both ends and connected to a steel strand to be tested when performing a fatigue tensile test.

Fig. 6 is a schematic view of an exploded structure of the clamp (one end) in fig. 1.

Fig. 7 is an enlarged structural view of B in fig. 6.

Fig. 8 is a schematic structural view of another embodiment of the locking sleeve of the clamp of the present invention.

Figure 9 is an exploded view of another embodiment of the clamp of the present invention.

The steel strand wires shown in the figure 1, a steel strand wire 2, a pressing sleeve 3, an outer barrel 4, an axial abutting column 5, a locking sleeve 6, a conical hole 7, a first internal thread 8, an elastic hoop ring 9, a second internal thread 10, a large-diameter column 11, a small-diameter column 12, a second external thread 13, a second annular groove 14, a first external thread 15, an opening 16, a locking piece 17, a cylindrical hole 18, a first annular groove 19, an axial threaded hole 20, a pressure spring 21, a bolt 22, a pressure ring 23, a through hole 24, a radial threaded hole 25 and a radial threaded pin.

Detailed Description

The following describes the present invention with reference to the accompanying drawings. It should be noted that the description of the embodiments is provided to help understanding the present invention, but the present invention is not limited thereto. In addition, the technical means described in the embodiments of the present invention may be combined with each other as long as they do not conflict with each other.

The prior art steel strand fatigue tensile test or steel strand axial stress fatigue test is carried out on a metal fatigue testing machine. And cutting off the steel strand with a certain length, clamping two ends of the steel strand by using a clamp for the fatigue tensile test of the steel strand, and connecting the steel strand with a metal fatigue testing machine by using the clamp through a connecting device. The clamps are used in pairs. The utility model discloses the use occasion and the connected mode of anchor clamps and this section prior art the same.

The invention of the utility model is characterized in that:

fig. 1, fig. 2, fig. 3, fig. 4, fig. 5, fig. 6, and fig. 7 show a first embodiment of the clamp of the present invention.

The utility model discloses anchor clamps that steel strand wires fatigue tensile test used, including urceolus 3. The above-mentioned connecting means is generally connected to the outer cylinder 3. A first internal thread 7 is arranged in a central hole at one end of the outer cylinder 3 close to the steel strand 1. A clamping sleeve 2 has a first external thread 14. The central hole of the pressing sleeve 2 is a conical hole 6 which is small near one end of the steel strand 1 and large far away from one end of the steel strand 1, a cylindrical hole 17 with a central hole sleeved with one end of the steel strand 1 is arranged in the conical hole 6, and a locking sleeve 5 with a conical outer circle matched with the conical hole 6 is arranged in the conical hole 6. At least the large end of the locking sleeve 5 is provided with a plurality of, for example 3, axially extending openings 15. The first external thread 14 on the pressing sleeve 2 and the first internal thread 7 on the outer cylinder 3 are screwed and the steel strand 1 at the end is locked through the locking sleeve 3. A second internal thread 9 is arranged in a central hole at one end of the outer barrel 3 far away from the steel strand 1, a second external thread 12 of an axial abutting column 4 is screwed with the second internal thread 9 of the outer barrel 3, and an inner end face of the axial abutting column 4 abuts against inner end faces of the locking sleeve 5 and the pressing sleeve 2. Since the steel strand to be tested is generally a plane, i.e., an end surface, cut by a cutting machine, the inner end surface of the axial abutment post 4 also generally abuts against the end surface of the steel strand 1. The outer end of the axial abutting column 4 is a screwing force application end. The axial abutting column 4 is preferably a stepped column, the second external thread 12 is arranged on the large-diameter column 10 of the stepped column, and the small-diameter column 11 of the stepped column is a screwing force application end. It is understood that the small-diameter column can be directly rotated by the pipe wrench by screwing force, or a polygonal column can be arranged at the outer end part of the small-diameter column for the wrench to clamp and rotate the small-diameter column. The outer diameter of the clamping sleeve 2 can be equal to the outer diameter of the outer cylinder 3. The outer cylinder 3 may also be referred to as a jacket. Plural generally means 2 or more than 2.

The outer cylinder 3, the pressing sleeve 2, the locking sleeve 5 and the axial abutting column 4 are all made of steel. In other words, the outer cylinder 3 is a steel outer cylinder. The pressing sleeve 2 is a steel pressing sleeve. The conical locking sleeve 5 is a steel locking sleeve. The axial abutting column 4 is a steel axial abutting column.

The central hole of the outer cylinder 3 is preferably a step hole, the diameter of the end close to the steel strand 1 is large, the first internal thread 7 is arranged in the large-diameter hole of the step hole, and the diameter of the end of the step hole provided with the second internal thread 9 is small. The compression sleeve 2 is a step sleeve, and the first external thread 14 is arranged on the small-diameter sleeve of the step sleeve. The outer diameter of the clamping sleeve 2 can be equal to the outer diameter of the outer cylinder 3.

The outer cylinder 3 is provided with a radial threaded hole 24 for preventing the pressing sleeve 2 from rotating relative to the outer cylinder 3 and a radial threaded pin 25 screwed in the radial threaded hole 24 and tightly abutted against the pressing sleeve 2. It will be understood that the outer end of the radially threaded pin 25 has a formation for the screwdriver to twist into, for example, a slotted groove.

The wall of the cylindrical hole 17 of the locking sleeve 5 is provided with an annular bulge or a copper sleeve or an aluminum sleeve (not shown in the figure). The outer wall of the big end of the locking sleeve 5 is provided with a second annular groove 13, and an elastic hoop 8 is arranged in the second annular groove 13.

Fig. 8 shows another embodiment of the locking sleeve of the clamp of the present invention: the plurality of axially extending openings 15 penetrate through two ends of the conical locking sleeve 5, so that a plurality of locking sheets 16, such as 3, are formed, and the plurality of locking sheets 16 are hooped at one end of the steel strand 1 by the elastic hoop 8 to form the conical locking sleeve. It will be appreciated that the locking tabs 16 are all steel locking tabs.

The clamps for clamping the two ends of the tested steel strand 1 are symmetrically arranged, and the clamps at the two ends are the same in shape, structure and size and opposite in direction.

Fig. 9 shows another embodiment of the clamp of the present invention: the small-diameter column 11 is sleeved with a pressure spring 20, the pressure spring 20 is accommodated in a first annular groove 18 between the small-diameter column 11 and the central hole at the end of the outer cylinder 3, the inner end of the pressure spring 20 abuts against the outer end face of the large-diameter column 10, and the outer end of the pressure spring 20 abuts against the inner end face of a pressure ring 22 which is fastened to the end face of the outer cylinder 3 through a bolt 21. The pressing ring 22 is provided with a through hole 23 for the bolt 21 to pass through, the end part of the large-diameter column 10 is provided with a plurality of axial threaded holes 19 for screwing the bolt 21, and the bolts 21 correspond to the through holes 23 and the axial threaded holes 19 one by one. The compression spring 20 is also called a compression spring. The rest of the structure is the same as that of the first embodiment.

Of course, the above other embodiment can also be replaced by a radial threaded hole and a radial screw, which is only a little troublesome to operate: the outer barrel 3 is provided with a radial threaded hole for preventing the axial abutting column from rotating relative to the outer barrel 3 and a radial threaded pin which is screwed in the radial threaded hole and abuts against the axial abutting column, and the outer end of the radial threaded pin is provided with a structure for screwing the screwdriver, such as a straight-line groove.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a anchor clamps that steel strand wires fatigue tensile test used, includes urceolus (3), its characterized in that: a first internal thread (7) is arranged in a central hole at one end of the outer barrel (3) close to the steel strand (1), a first external thread (14) is arranged on a pressing sleeve (2), the central hole of the pressing sleeve (2) is a conical hole (6) which is small at one end close to the steel strand (1) and large at one end far away from the steel strand (1), a cylindrical hole (17) which is sleeved with one end of the steel strand (1) is arranged in the conical hole (6), a locking sleeve (5) which is conical and matched with the conical hole (6) in the excircle is arranged in the central hole, a plurality of axially extending openings (15) are arranged at least on the large end of the locking sleeve (5), and the first external thread (14) on the pressing sleeve (2) and the first internal thread (7) on the outer barrel (3) are combined in a rotating manner and locked on the steel strand (1) at the end through the locking sleeve (5); a second internal thread (9) is arranged in a central hole at one end, far away from the steel strand (1), of the outer barrel (3), a second external thread (12) of an axial abutting column (4) is screwed with the second internal thread (9), the inner end face of the axial abutting column (4) is abutted with the inner end faces of the locking sleeve (5) and the pressing sleeve (2), and the outer end of the axial abutting column (4) is a screwing force application end.

2. The clamp for the fatigue tensile test of the steel strand according to claim 1, wherein: the outer cylinder (3), the pressing sleeve (2), the locking sleeve (5) and the axial abutting column (4) are all made of steel.

3. The clamp for the fatigue tensile test of the steel strand according to claim 1, wherein: the central hole of the outer barrel (3) is a stepped hole, the diameter of the hole close to one end of the steel strand (1) is large, the first internal thread (7) is arranged in the large-diameter hole of the stepped hole, and the diameter of the hole at the end of the stepped hole provided with the second internal thread (9) is small; the compression sleeve (2) is a step sleeve, and the first external thread (14) is arranged on the small-diameter sleeve of the step sleeve.

4. The clamp for the fatigue tensile test of the steel strand according to claim 1, wherein: the outer cylinder (3) is provided with a radial threaded hole (24) for preventing the pressing sleeve (2) from rotating relative to the outer cylinder (3) and a radial threaded pin (25) which is screwed in the radial threaded hole (24) and tightly abuts against the pressing sleeve (2).

5. The clamp for the fatigue tensile test of the steel strand according to claim 1, wherein: the axial abutting column (4) is a step column, the second external thread (12) is arranged on a large-diameter column (10) of the step column, and a small-diameter column (11) of the step column is a screwing force application end.

6. The clamp for the fatigue tensile test of the steel strand according to claim 5, wherein: the small-diameter column (11) is sleeved with a pressure spring (20), the pressure spring (20) is accommodated in a first annular groove (18) between the small-diameter column (11) and the center hole of the end of the outer cylinder (3), the inner end of the pressure spring (20) abuts against the outer end face of the large-diameter column (10), and the outer end of the pressure spring (20) abuts against the inner end face of a pressure ring (22) which is fastened on the end face of the outer cylinder (3) through a bolt (21).

7. The clamp for the fatigue tensile test of the steel strand according to claim 1, wherein: the hole wall of the cylindrical hole (17) of the locking sleeve (5) is provided with an annular bulge or a copper sleeve or an aluminum sleeve.

8. The clamp for the fatigue tensile test of the steel strand according to claim 1, wherein: the outer wall of the big head end of the locking sleeve (5) is provided with a second annular groove (13), and an elastic hoop (8) is arranged in the second annular groove (13).

9. The clamp for the fatigue tensile test of the steel strand according to claim 8, wherein: the plurality of axially extending openings (15) penetrate through two ends of the locking sleeve (5) to form a plurality of locking sheets (16), and the plurality of locking sheets are hooped at one end of the steel strand (1) by the elastic hoop (8) to form the conical locking sleeve.

10. The clamp for the fatigue tensile test of the steel strand according to any one of claims 1 to 9, characterized in that: the clamps for clamping the two ends of the tested steel strand (1) are symmetrically arranged, and the clamps at the two ends are the same in shape, structure and size and opposite in direction.