CN220207299U - Constant tensile load testing machine - Google Patents

Abstract

The utility model provides a constant tensile load testing machine, which comprises a rack, a lever, weights and a loading rod, wherein the loading rod is arranged on the rack; the side part of the frame is provided with a bearing seat; the lever is hinged to the upper end of the rack through a hinge shaft, the lever is provided with a loading end and a bearing end, the loading end is provided with a first arc-shaped surface, and the bearing end is provided with a second arc-shaped surface; the weight is connected to the loading end through a first rope body; the loading rod is connected to the bearing end through a second rope body, and a loading seat is arranged at the lower end of the loading rod. According to the constant tensile load testing machine provided by the utility model, the load end of the lever is provided with the weight to realize the multiple increase of the tensile force of the load end, the implementation of a larger loading force value can be realized through the weight with smaller weight, when a tested sample generates a pull rope and the lever rotates around the hinge shaft, the first arc-shaped surface and the second arc-shaped surface respectively support and limit the tensile force direction of the first rope body and the second rope body, the constant lever ratio of the lever is ensured, the stability of the loading force value is ensured, and the accuracy of the test is further ensured.

Description

Constant tensile load testing machine

Technical Field

The utility model belongs to the technical field of tensile tests, and particularly relates to a constant tensile load testing machine.

Background

When a plastic material is subjected to stress or strain in air below the yield point, stress cracking may occur over time. These stresses may be internal or external, or a combination of both. Compared with the inert environment, the material is exposed to the chemical environment, the failure time can be obviously shortened under the action of stress or strain, the allowable long-term stress or strain of the material is obviously reduced, the material is a main form of damage in the use process of the material, and the service life of the material can be seriously shortened.

In the prior art, in the process of testing materials, a constant force value is applied to a tested sample for a long time so as to ensure the accuracy of test results, but the conventional test equipment is subjected to power supply, so that the problem of loading force value failure caused by power failure and other conditions is solved, the continuity of the test is difficult to ensure, and the accuracy of the test results is influenced.

Disclosure of Invention

The utility model aims to provide a constant tensile load testing machine which can provide stable loading force for a tested sample body in a lever force value multiplication mode, so that the accuracy of the test is ensured.

In order to achieve the above purpose, the utility model adopts the following technical scheme: provided is a constant tensile load testing machine including:

the side part of the rack is provided with a bearing seat for installing a tested sample;

the lever is hinged to the upper end of the frame through a horizontally extending hinge shaft, the lever is provided with a loading end and a bearing end which are respectively positioned at two sides of the hinge shaft, the bearing end and the bearing seat are positioned at the same side of the frame, the loading end is provided with a first arc-shaped surface which extends in an arc manner around the axis of the hinge shaft, and the bearing end is provided with a second arc-shaped surface which extends in an arc manner around the axis of the hinge shaft;

the weight is connected to the loading end through a first rope body;

the loading rod is connected to the bearing end through a second rope body, and the lower end of the loading rod is provided with a loading seat connected with the upper part of the tested sample, and the loading seat is used for applying constant stretching force to the tested sample;

when the lever swings vertically around the hinge shaft, the first rope body can be partially attached to the first arc-shaped surface, and the second rope body can be partially attached to the second arc-shaped surface, so that the lever ratio of the lever is constant.

In one possible implementation manner, the loading rod is connected to the lower end of the second rope body through a connecting component, a boss protruding towards the periphery is arranged at the upper end of the loading rod, the connecting component comprises a connecting sleeve sleeved on the periphery of the loading rod and a connecting seat in threaded connection above the connecting sleeve, the connecting sleeve is provided with a lower end plate for the loading rod to penetrate through and used for supporting the boss, and the connecting seat is connected with the lower end of the second rope body.

In some embodiments, the connecting seat is provided with a first hole penetrating up and down to allow the second rope to penetrate, the connecting seat is provided with a locking bolt extending radially along the connecting seat, the locking bolt is provided with a second hole extending radially to allow the second rope to penetrate, and the locking bolt is in threaded connection with the connecting seat and is used for rotating relative to the connecting seat to lock the second rope.

In one possible implementation manner, the side part of the frame is further provided with a buffer loading assembly capable of supporting the weight below, and the buffer loading assembly comprises a lifting driving part connected to the frame in the up-down direction, a supporting bracket connected to the upper end of the lifting driving part, and an elastic supporting part arranged above the supporting bracket to support the weight.

In some embodiments, the elastic supporting member includes at least two elastic members connected to the supporting bracket in an up-down direction, and a supporting plate connected to an upper end of the elastic members and used for supporting weights.

In some embodiments, a plurality of guide posts which are in one-to-one correspondence with the elastic pieces and are coaxially arranged are connected to the bottom surface of the supporting plate, the guide posts penetrate through the elastic pieces and the supporting bracket to be arranged and are in sliding fit with the supporting bracket, and a guide rod which extends downwards and is in sliding fit with the supporting bracket is also connected to the bottom surface of the supporting plate.

In one possible implementation manner, the bearing end is further connected with an outwardly extending counterweight rod, a counterweight is sleeved on the counterweight rod, and two locking nuts respectively positioned on two sides of the counterweight to lock positions of the counterweight are sleeved on the counterweight rod.

In one possible implementation, the loading end has an upwardly projecting extension seat, the first arcuate surface being disposed on a side of the extension seat remote from the hinge axis, the extension seat being provided with a horizontally extending lightening hole.

In one possible implementation, a medium box is further arranged on the rack, located below the loading rod and used for containing a medium, a heating element is arranged in the medium box, and the medium box can move up and down to enable a tested sample to be immersed in the medium.

In some embodiments, the levers are arranged at intervals in the axial direction of the hinge shaft, and the medium box is provided with one lever and is correspondingly positioned below the levers.

Compared with the prior art, the scheme that this application embodiment shows, the constant tensile load testing machine that this application embodiment provided realizes the multiple increase of loading end tensile force through setting up the weight at the loading end of lever, can realize the implementation of great loading force value through the weight that weight is less, when the stay cord takes place for the test sample, the lever is rotatory around the articulated shaft, the first arcwall face of loading end and the second arcwall face of bearing end support the pulling force direction of prescribing a limit to first rope body and second rope body respectively, the lever ratio of assurance lever is invariable, avoid influencing loading force direction and numerical accuracy because of being tested sample elongation deformation, the stability of loading force value has been guaranteed, and then the precision of experiment has been guaranteed.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a front view structure of a constant tensile load testing machine according to an embodiment of the present utility model;

FIG. 2 is a schematic cross-sectional view of A-A of FIG. 1 in accordance with an embodiment of the present utility model;

FIG. 3 is a schematic diagram of the structure of FIG. 2 with the buffer loading assembly and the media box omitted;

FIG. 4 is a schematic view of a partial enlarged structure of I in FIG. 3 according to an embodiment of the present utility model;

FIG. 5 is a schematic diagram illustrating a partial cross-sectional structure of the buffer loading assembly of FIG. 2 according to an embodiment of the present utility model.

Wherein, each reference sign in the figure:

1. a frame; 11. a bearing seat; 12. a media box; 13. a heating element; 2. a lever; 21. a first arcuate surface; 22. a second arcuate surface; 23. a hinge shaft; 24. an extension seat; 241. a lightening hole; 3. a weight; 31. a first rope; 4. a loading rod; 41. a second rope; 42. a boss; 43. a loading seat; 5. a connection assembly; 51. connecting sleeves; 511. a lower end plate; 52. a connecting seat; 521. a first hole; 53. a locking bolt; 531. a second hole; 6. a buffer loading assembly; 61. a lifting driving member; 62. a support bracket; 63. an elastic support; 631. an elastic member; 632. a supporting plate; 64. a guide post; 65. a guide rod; 71. a weight bar; 72. a counterweight; 73. a lock nut; 8. the sample to be tested.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the utility model is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or be indirectly on the other element. It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate describing the present utility model and simplify the description, and do not indicate or imply that the devices or elements being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the present utility model. The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present utility model, the meaning of "a number" is two or more, unless explicitly defined otherwise.

Referring to fig. 1 to 5, a description will be given of a constant tensile load testing machine according to the present utility model. The constant tensile load testing machine comprises a frame 1, a lever 2, weights 3 and a loading rod 4; the side part of the frame 1 is provided with a bearing seat 11 for installing a tested sample 8; the lever 2 is hinged to the upper end of the frame 1 through a horizontally extending hinge shaft 23, the lever 2 is provided with a loading end and a bearing end which are respectively positioned at two sides of the hinge shaft 23, the bearing end and the bearing seat 11 are positioned at the same side of the frame 1, the loading end is provided with a first arc-shaped surface 21 which extends in an arc shape around the axis of the hinge shaft 23, and the bearing end is provided with a second arc-shaped surface 22 which extends in an arc shape around the axis of the hinge shaft 23; the weight 3 is connected to the loading end through a first rope 31; the loading rod 4 is connected to the bearing end through a second rope 41, and the lower end of the loading rod 4 is provided with a loading seat 43 connected with the upper part of the tested sample 8, and the loading seat 43 is used for applying constant stretching force to the tested sample 8;

wherein, when the lever 2 swings vertically around the hinge shaft 23, the first rope 31 can be partially attached to the first arc surface 21, and the second rope 41 can be partially attached to the second arc surface 22, so that the lever ratio of the lever 2 is constant.

Compared with the prior art, the constant tensile load testing machine provided by the embodiment has the advantages that the weight 3 is arranged at the loading end of the lever 2 to realize the doubling of the tensile force of the loading end, the weight 3 with smaller weight can realize the implementation of larger loading force value, when the tested sample 8 stretches and the lever 2 rotates around the hinge shaft 23, the first arc-shaped surface 21 of the loading end and the second arc-shaped surface 22 of the bearing end support and limit the tensile force direction of the first rope body 31 and the second rope body 41 respectively, the lever ratio of the lever 2 is ensured to be constant, the influence on the loading force direction and the accuracy of the numerical value due to the stretching deformation of the tested sample 8 is avoided, the stability of the loading force value is ensured, and the accuracy of the test is further ensured.

The lever ratio refers to a ratio of a distance from the first rope 31 to the hinge shaft 23 to a distance from the second rope 41 to the hinge shaft 23.

Specifically, the distance between the hinge shaft 23 and the second rope 41 is larger than the distance between the hinge shaft 23 and the first rope 31, the load applied to the tested sample 8 by the second rope 41 is effectively increased through the arrangement, the effect of multiplying the loading force is achieved, the equipment cost is saved, and the operation of operators is facilitated.

Through setting up first arcwall face 21 and second arcwall face 22, make the arm of force length of first rope body 31 and second rope body 41 keep invariable ratio, and then make the two self keep stable pulling force value, reach the invariable tensile effect of exerting of test sample 8 to guarantee the accuracy of test.

When the tested sample 8 is stretched under the action of the tension of the loading rod 4, the lever 2 rotates slightly around the hinge shaft 23, the loading end moves slightly downwards at the moment, the first rope 31 is still in a vertical state under the action of the weight 3, but the contact critical point of the first rope 31 and the first arc-shaped surface 21 moves upwards relative to the first arc-shaped surface 21, and the force arm from the first rope 31 to the hinge shaft 23 and the tension value of the first rope 31 are kept constant and unchanged.

Meanwhile, the bearing end moves up slightly, the second rope 41 is still in a vertical state under the action of the tested tensile force, but the contact critical point of the second rope 41 and the second arc-shaped surface 22 moves downwards relative to the second arc-shaped surface 22, and the force arm from the second rope 41 to the hinge shaft 23 and the tensile force value of the second rope 41 are kept constant and have no change.

By the arrangement of the structure, in the test process, although the lever 2 swings vertically, the tensile force value borne by the tested sample 8 is not influenced, and the tested sample 8 can bear a constant loading force value, so that the test loading requirement is met. The loading mode furthest avoids the influence of external environment, such as power supply and the like, and avoids test interruption caused by failure of loading force value when power failure occurs. The loading mode is particularly suitable for long-term test.

In a possible implementation manner, referring to fig. 1 to 5, the loading rod 4 is connected to the lower end of the second rope 41 through a connection assembly 5, a boss 42 protruding toward the periphery is provided at the upper end of the loading rod 4, the connection assembly 5 includes a connection sleeve 51 sleeved on the periphery of the loading rod 4 and a connection seat 52 screwed above the connection sleeve 51, the connection sleeve 51 has a lower end plate 511 for supporting the boss 42 and penetrating the loading rod 4, and the connection seat 52 is connected to the lower end of the second rope 41.

In this embodiment, the loading rod 4 below the second rope 41 provides a stable installation basis for the arrangement of the loading seat 43. The second rope 41 is connected with the loading rod 4 through the connecting component 5. The connecting assembly 5 adopts the connecting seat 52 and the connecting sleeve 51 which are in threaded connection, and the axial length can be adjusted by adjusting the relative positions of the connecting seat and the connecting sleeve, namely the size in the up-down direction is adjusted, so that the device is suitable for the tested samples 8 with different sizes and specifications, and the practicability of the device is improved.

Specifically, the lower end plate 511 of the connecting sleeve 51 can support and limit the boss 42 at the upper end of the loading rod 4, so that the connecting sleeve 51 and the loading rod 4 are effectively connected. When the connecting sleeve 51 and the connecting seat 52 rotate relatively, the connecting sleeve 51 can rotate circumferentially relative to the loading rod 4, the loading rod 4 and the loading seat 43 keep the original positions and do not synchronously rotate, and the trouble of adjusting the positions of the loading rod 4 and the loading seat 43 to adapt to the tested sample 8 is omitted.

In some embodiments, referring to fig. 1 to 5, a first hole 521 penetrating up and down for the second rope 41 to penetrate is provided on the connecting seat 52, a locking bolt 53 extending radially is provided on the connecting seat 52, a second hole 531 extending radially for the second rope 41 to penetrate is provided on the locking bolt 53, and the locking bolt 53 is in threaded connection with the connecting seat 52 and is used for rotating relative to the connecting seat 52 to lock the second rope 41.

In this embodiment, the locking bolt 53 extending along the radial direction of the connection seat 52 is disposed on the peripheral wall of the connection seat 52, the second rope 41 penetrates through the first hole 521 of the connection seat 52 and the second hole 531 of the locking bolt 53, when the second rope 41 needs to be locked on the connection seat 52, the locking bolt 53 is screwed to rotate circumferentially, so that the second rope 41 is clamped at the intersection of the first hole 521 and the second hole 531, locking of the relative position of the second rope 41 and the connection seat 52 is achieved, the tensile force of the second rope 41 is ensured to be transmitted to the tested sample 8 through the loading rod 4 below, good connection reliability is achieved, and meanwhile, the length of the connection assembly 5 is also convenient to adjust to adapt to the tested samples 8 with different specifications.

In a possible implementation, referring to fig. 1 to 5, the side portion of the frame 1 is further provided with a buffer loading assembly 6 capable of supporting the weight 3 below, and the buffer loading assembly 6 includes a lifting driving member 61 connected to the frame 1 in the up-down direction, a supporting bracket 62 connected to the upper end of the lifting driving member 61, and an elastic supporting member 63 disposed above the supporting bracket 62 to support the weight 3.

In this embodiment, the buffer loading assembly 6 is used to provide no impact load to the test specimen, and at the same time, to eliminate impact shock caused by dropping of the weight 3 when the test specimen 8 is pulled to break.

The lifting driving member 61 can move upwards to drive the supporting bracket 62 and the elastic supporting member 63 above to move upwards and support the bottom of the weight 3. When a tensile load is required to be applied to the tested sample 8, the lifting driving piece 61 is slowly moved downwards, and at the moment, the elastic piece 631 stretches under the action of elasticity and props against the bottom of the weight 3, so that the bearing force below the weight 3 is gradually reduced until the elastic piece 631 is completely separated from the weight 3, stable loading of the tested sample 8 is realized, and damage to the tested sample 8 caused by impact is avoided.

In addition, the setting number of the buffer loading components 6 is consistent with the setting number of the levers 2, so that the stable and orderly loading process of the weights 3 on the tested sample 8 is ensured.

In some embodiments, referring to fig. 1 to 5, the elastic supporting member 63 includes at least two elastic members 631 connected to the supporting frame 62 in the up-down direction, and a supporting plate 632 connected to the upper end of the elastic members 631 for supporting the weights 3. In this embodiment, the elastic members 631 may be two, three or four, so as to effectively support the supporting plate 632. The elastic member 631 can provide upward elastic pushing force for the supporting plate 632, and in the process of moving down the lifting driving member 61, the elastic member 631 gradually extends under the action of the elastic force and makes the supporting plate 632 abut against the bottom surface of the weight 3, and along with the downward movement of the lifting driving member 61, the weight 3 gradually loses the supporting effect of the supporting plate 632, so as to realize gradual loading of the tested sample 8.

In some embodiments, referring to fig. 1 to 5, a plurality of guide posts 64 corresponding to the elastic members 631 one by one and coaxially arranged are connected to the bottom surface of the supporting plate 632, the guide posts 64 penetrate the elastic members 631 and the supporting bracket 62 and are slidably matched with the supporting bracket 62, and a guide rod 65 extending downwards and slidably matched with the supporting bracket 62 is also connected to the bottom surface of the supporting plate 632.

In this embodiment, the guide post 64 can form a limiting effect on the elastic member 631, so as to avoid bending deformation of the elastic member 631 caused by overlarge gravity of the weight 3, and the lower end of the guide post 64 is connected with a limiting block, so that the limiting block can avoid the guide post 64 from falling out from the upper portion of the support bracket 62. On the basis, a guide rod 65 is arranged at the bottom of the supporting plate 632, the guide rod 65 has an auxiliary guiding function, and the supporting plate 632 is smooth in the lifting process, so that the stable operation of the structure is ensured.

In a possible implementation, referring to fig. 1 to 5, the bearing end is further connected with an outwardly extending weight bar 71, a weight 72 is sleeved on the weight bar 71, and two locking nuts 73 respectively located at two sides of the weight 72 to lock the position of the weight 72 are sleeved on the weight bar 71.

In this embodiment, the load-bearing end is provided with a weight bar 71 for installing a weight 72, the weight 72 with a proper specification is selected according to the requirement, the weight 72 is sleeved on the periphery of the weight bar 71 and locked by two locking nuts 73, so that the stability of installation of the device is ensured.

In one possible implementation, referring to fig. 1 to 5, the loading end has an extension seat 24 protruding upward, the first arc surface 21 is disposed on a side of the extension seat 24 away from the hinge shaft 23, and the extension seat 24 is provided with a weight-reducing hole 241 that is horizontally penetrated.

In this embodiment, since the distance between the hinge shaft 23 and the second rope 41 is greater than the distance between the hinge shaft 23 and the first rope 31, when the lever 2 rotates around the hinge shaft 23, the vertical swing displacement of the loading end is far greater than the vertical swing displacement of the bearing end, and for facilitating the arrangement of the first arc surface 21, the extending seat 24 is disposed at the loading end, and the first arc surface 21 is disposed on the outer side of the extending seat 24, so as to ensure the constant lever ratio in the swinging process of the lever 2.

On this basis, in order to reduce the material consumption, the weight reducing holes 241 are formed in the extension base 24, so that the material consumption of the lever 2 is reduced, and the lightweight design is realized.

In a possible implementation, referring to fig. 1 to 5, the rack 1 is further provided with a medium box 12 located below the loading rod 4 and used for accommodating a medium, a heating element 13 is provided in the medium box 12, and the medium box 12 can move up and down for the tested sample 8 to be immersed in the medium.

In this embodiment, the media box 12 provides a media environment for the test, including the test media and the temperature field. The heating element 13 can heat the medium in the medium box 12, so that the tested sample 8 is at a proper temperature, and the proper test environment is ensured.

On this basis, in order to improve the test efficiency, a plurality of levers 2 are arranged at intervals in the axial direction of the hinge shaft 23, and the medium box 12 is provided with one and correspondingly positioned below the plurality of levers 2. The tested sample 8 below the levers 2 is accommodated by one medium box 12, so that the device structure is simplified, and the test efficiency is improved.

The using process comprises the following steps:

according to the test requirements, the medium is added into the medium box 12, and the temperature of the medium is regulated by the heating element 13, so that the medium environment and the temperature field required by the test are achieved. The buffer loading assembly 6 is started, the weight 3 is lifted upwards, and no loading force value is ensured at the moment. The sample 8 is mounted between the carrier 11 and the loading base 43, and the sample 8 is moved up into the medium box 12 by the medium box 12. The lifting driving piece 61 moves downwards to enable the elastic supporting piece 63 to gradually separate from the weight 3, the weight of the weight 3 is multiplied by the force value through the lever 2, and the force value is applied to the tested sample 8, so that the loading of the force value is completed.

After that, the tested sample 8 is pulled under the action of tensile force, the lever 2 rotates slightly around the hinge shaft 23, the loading end moves slightly downwards, the bearing end moves slightly upwards, the contact critical point of the first rope 31 and the first arc-shaped surface 21 moves relatively upwards, the contact critical point of the second rope 41 and the second arc-shaped surface 22 moves relatively downwards, the lever ratio is kept constant until the test is finished, the device can realize static loading in a natural state, the requirement on the external environment is small, the loading state is not influenced when the device is powered off, and the device is particularly important for ensuring the stability of long-term test.

The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the utility model.

Claims (10)

1. A constant tensile load testing machine, comprising:

the side part of the rack is provided with a bearing seat for installing a tested sample;

the lever is hinged to the upper end of the frame through a horizontally extending hinge shaft, the lever is provided with a loading end and a bearing end which are respectively positioned at two sides of the hinge shaft, the bearing end and the bearing seat are positioned at the same side of the frame, the loading end is provided with a first arc-shaped surface which extends in an arc manner around the axis of the hinge shaft, and the bearing end is provided with a second arc-shaped surface which extends in an arc manner around the axis of the hinge shaft;

the weight is connected to the loading end through a first rope body;

the loading rod is connected to the bearing end through a second rope body, the lower end of the loading rod is provided with a loading seat connected with the upper part of the tested sample, and the loading seat is used for applying constant stretching force to the tested sample;

when the lever swings vertically around the hinge shaft, the first rope body can be partially attached to the first arc-shaped surface, and the second rope body can be partially attached to the second arc-shaped surface, so that the lever ratio of the lever is constant.

2. The constant tension load testing machine according to claim 1, wherein the loading rod is connected to the lower end of the second rope body through a connecting assembly, a boss protruding towards the periphery is arranged at the upper end of the loading rod, the connecting assembly comprises a connecting sleeve sleeved on the periphery of the loading rod and a connecting seat in threaded connection with the upper portion of the connecting sleeve, the connecting sleeve is provided with a lower end plate for the loading rod to penetrate through and used for supporting the boss, and the connecting seat is connected with the lower end of the second rope body.

3. The constant tension load testing machine according to claim 2, wherein the connecting seat is provided with a first hole penetrating through the second rope vertically, the connecting seat is provided with a locking bolt extending along the radial direction of the connecting seat, the locking bolt is provided with a second hole extending along the radial direction of the connecting seat and used for locking the second rope by rotating relative to the connecting seat, and the locking bolt is in threaded connection with the connecting seat.

4. The constant tension load testing machine according to claim 1, wherein the side of the frame is further provided with a buffer loading assembly capable of supporting the weight below the weight, and the buffer loading assembly comprises a lifting driving member connected to the frame in an up-down direction, a support bracket connected to an upper end of the lifting driving member, and an elastic supporting member disposed above the support bracket to support the weight.

5. The constant tension load testing machine according to claim 4, wherein the elastic supporting member comprises at least two elastic members connected to the supporting bracket in an up-down direction and a supporting plate connected to an upper end of the elastic members for supporting the weights.

6. The constant tension load testing machine according to claim 5, wherein a plurality of guide posts which are in one-to-one correspondence with the elastic pieces and are coaxially arranged are connected to the bottom surface of the supporting plate, the guide posts penetrate through the elastic pieces and the supporting bracket and are in sliding fit with the supporting bracket, and a guide rod which extends downwards and is in sliding fit with the supporting bracket is also connected to the bottom surface of the supporting plate.

7. The constant tension load testing machine according to any one of claims 1-6, wherein the bearing end is further connected with an outwardly extending weight bar, a weight is sleeved on the weight bar, and two locking nuts are respectively arranged on two sides of the weight bar in a threaded manner to lock the position of the weight.

8. The constant tension load testing machine according to any one of claims 1-6, wherein the loading end has an upwardly projecting extension seat, the first arcuate surface being disposed on a side of the extension seat remote from the hinge shaft, the extension seat being provided with a horizontally extending weight-reducing aperture.

9. The constant tension load testing machine according to any one of claims 1-6, wherein a medium box is arranged below the loading rod and used for containing a medium, and a heating element is arranged in the medium box, and the medium box can move up and down to allow a tested sample to be immersed in the medium.

10. The constant tension load testing machine according to claim 9, wherein the levers are arranged at intervals in the axial direction of the hinge shaft, and the medium box is arranged one and correspondingly positioned below the levers.