Mechanical clamp for material tension and compression fatigue test

Abstract

The utility model discloses a mechanical clamp for a material tension and compression fatigue test. The mechanical clamp comprises a buckle, a fixing bolt, a fixing bottom plate, a base, a gland, a fixing sleeve, a fixing bolt and a flat clamp, the buckle is of a frame structure, the upper edge and the lower edge of the buckle are each provided with a buckle threaded hole, and the upper end of the fixing bolt is in threaded connection with the buckle threaded hole in the lower edge of the buckle and fastened through the fastening nut. The lower end of the fixing sleeve is in threaded connection with the upper top surface of the fixing bottom plate; the lower bottom surface of the fixing bottom plate is in threaded connection with the base through fixing bolts; an inverted trapezoidal groove with a short lower part and a long upper part is formed in the gland, two flat tongs are arranged in the inverted trapezoidal groove, and the gland is in threaded connection with the connecting base through a height adjusting bolt; the fixing bolt is sleeved with the fixing sleeve, through holes are transversely formed in the corresponding positions of the fixing bolt and the fixing sleeve, and the fixing bolt transversely penetrates through the through holes to connect the fixing bolt with the fixing sleeve. The multifunctional tester is simple in structure, low in cost, capable of carrying out a tensile test and a compression test, and diversified in function.

Description

TECHNICAL FIELD

[0001] The utility model relates to a mechanical clamp, particularly to a mechanical clamp for material tension and compression fatigue test. BACKGROUND

[0002] In the field of material tensile and compressive strength testing, to test the material's resistance to tension and compression performance, a universal material testing machine is usually used. The sample is clamped by two end clamps, and the clamping is realized by air pressure or hydraulic system after clamping, which can provide uniform and adjustable clamping force, and is suitable for testing large or heavy materials. The clamp of the universal material testing machine is usually composed of lower clamp, upper clamp, alignment device, clamping mechanism, pressure plate, adapter and other elements. Its specific working principle is that the hydraulic clamp uses hydraulic oil as the medium for transmitting power. When the operator starts the hydraulic system, the hydraulic pump pumps the hydraulic oil out of the oil tank and delivers it to the hydraulic cylinder through the control valve. The piston in the hydraulic cylinder is pushed by the hydraulic oil, thereby generating clamping force. By adjusting the pressure in the hydraulic system, the size of the clamping force can be accurately controlled. The operator can set appropriate pressure according to the test requirements to ensure that the material is clamped firmly. After completing the test, the operator can release the hydraulic oil through the control valve to make the piston retract, thereby releasing the clamp and facilitating the removal of the test material.

[0003] Although the hydraulic clamp has many advantages in material tensile and compressive strength testing, it also has some disadvantages, mainly including complexity, risk of failure, higher cost, slow response speed, large weight and volume, large energy consumption, and sensitivity to temperature. The hydraulic system is relatively complex, involving multiple components (such as pumps, valves, pipes, etc.), which may increase the difficulty of maintenance and operation. Secondly, the hydraulic system may leak, clog or have other failures, causing the clamp to malfunction or the clamping force to be unstable, thereby affecting the test results. Compared with mechanical clamps, hydraulic clamps are usually more expensive and require additional hydraulic equipment and maintenance in terms of maintenance. In terms of energy consumption, the hydraulic system requires energy (usually electricity) to drive the pump and other components, increasing the energy consumption of the equipment. In terms of response speed, the clamping and releasing speed of the hydraulic clamp may be slower, especially in the case of frequent replacement of test samples, which may affect the test efficiency. Hydraulic clamps are usually heavier and larger than mechanical clamps, which may not be suitable for laboratory environments with limited space. In addition to the requirement for experimental space, the performance of hydraulic oil may be affected by temperature changes, and extreme temperatures may cause the hydraulic effect to be unstable. The current traditional mechanical clamp can only realize single compression or single tension test, and if the test type needs to be changed, the clamp needs to be replaced, which greatly reduces the test efficiency. SUMMARY

[0004] The utility model provides a mechanical clamp for material tension-compression fatigue test, simple structure, multiple functions, stable clamping, good test effect.

[0005] In order to realize the above-mentioned purpose, the utility model provides the following technical scheme: including buckle, fixed peg, fixed bottom plate, base, gland, fixed sleeve, fixed bolt and flat tongs, the buckle is frame structure, and one buckle screw hole is equipped on the upper and lower two sides respectively, and the fixed peg upper end is connected with the buckle screw hole of buckle lower edge and is fastened through the lock nut, the lower end of fixed sleeve is connected with the fixed bottom plate upper top surface threadedly, and the fixed bottom plate lower bottom is connected with the base through fixed bolt threadedly, the inside of gland is equipped with the inverted trapezoidal groove of lower short upper long, two flat tongs are arranged in the inverted trapezoidal groove, and the gland is connected with the connecting base threadedly through height adjusting bolt.

[0006] Further, the top end of the fixed sleeve abuts against the lower edge of the buckle after the fixed sleeve is connected with the fixed peg.

[0007] Further, the height of the flat tongs is greater than the height of the inverted trapezoidal groove.

[0008] Further, the buckle is an octagonal frame structure.

[0009] Further, the contact surface between the flat tongs and the inverted trapezoidal groove in the gland is provided with lubricating grease.

[0010] Compared with the prior art, the utility model has the advantages that compared with hydraulic or pneumatic clamp, the utility model has simple structure, low manufacturing and maintenance cost, convenient operation, can quickly clamp and unclamp the sample, saves test preparation time, can carry out tensile test and compression test, has multiple functions, the inverted trapezoidal groove in the flat tongs and the gland is of lower short upper long structure, when the sample is placed in the flat tongs, the symmetrical inclined plane uniformly exerts force from both sides, effectively avoids the situation that the sample is subjected to too large or uneven force on one side, and thus the centring property of the sample is effectively ensured, when carrying out tensile test, the self-locking property is good, and it is not necessary to continuously exert additional force to maintain the fixed state, thereby improving the safety of operation, is suitable for small load tension-compression zero-crossing experiment, force transmission is uniform, can uniformly exert and transmit force to the sample, reduces stress concentration phenomenon, and improves the reliability of test result. BRIEF DESCRIPTION OF DRAWINGS

[0011] Fig. 1 It is the utility model structure section view;

[0012] Fig. 2 It is the utility model side view;

[0013] Fig. 3 This is a perspective view of the present utility model;

[0014] In the diagram: 1. Flat clamp; 2. Height adjustment bolt; 3. Pressure cap; 4. Fixing bolt; 5. Fixing sleeve; 6. Set nut; 7. Threaded buckle hole; 8. Buckle; 9. Fixing bolt; 10. Fixing pin; 11. Fixing base plate; 12. Base. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] like Figs. 1 to 3 As shown, this utility model provides a technical solution including a buckle 8, a fixing bolt 9, a fixing base plate 11, a base 12, a pressure cap 3, a fixing sleeve 5, a fixing pin 10, and a flat clamp 1.

[0018] The buckle 8 has an octagonal frame structure. This structure ensures that the buckle 8 is not easily deformed, and its octagonal shape can reduce stress concentration and further enhance the stability of the equipment. The buckle 8 has a buckle thread hole 7 on both the upper and lower sides. The upper end of the fixing bolt 9 is threaded to the buckle thread hole 7 on the lower side of the buckle 8 and is fastened by the set nut 6. The lower end of the fixing sleeve 5 is threaded to the top surface of the fixing base plate 11. The bottom surface of the fixing base plate 11 is threaded to the base 12 by the fixing bolt 4. The pressure cap 3 has an inverted trapezoidal groove with a shorter bottom and a longer top. Two flat clamps 1 are set in the inverted trapezoidal groove. The height of the flat clamps 1 is greater than the height of the inverted trapezoidal groove. The pressure cap 3 is threaded to the connecting base 12 by the height adjustment bolt 2. The relative distance between the pressure cap 3 and the connecting base 12 can be adjusted by adjusting the height adjustment bolt 2. Since the two flat clamps 1 and the inverted trapezoidal groove are all of the structure with a shorter bottom and a longer top, when the relative distance between the pressure cap 3 and the connecting base 12 is small, the pressure cap 3 will exert a squeezing force on the flat clamps 1 inward, thereby achieving the purpose of clamping the sample.

[0019] The fixing sleeve 5 is fitted over the fixing bolt 9. The fixing bolt 9 and the fixing sleeve 5 are provided with transverse through holes at corresponding positions. The fixing pin 10 passes through the through holes to connect the fixing bolt 9 and the fixing sleeve 5. After the fixing sleeve 5 is connected to the fixing bolt 9, the top of the fixing sleeve 5 abuts against the bottom of the buckle 8. This can prevent relative rotation between the fixing sleeve 5 and the fixing bolt 9 and improve the connection strength.

[0020] Before the compression test, the height adjusting bolt 2 is loosened to make the compression cap 3 lower, and the distance between the compression cap 3 and the connecting base 12 is as large as possible, so as to clamp the sample; first, the buckle screw hole 7 on the upper edge of the buckle 8 is connected with the main machine of the testing machine, then the two flat tongs 1 are held upward to make the opening of the flat tongs 1 open, the top end of the sample is placed in the opening of the two flat tongs 1, then the two flat tongs 1 are loosened, and the two flat tongs 1 will automatically slide downward and automatically center and clamp the sample under the action of gravity, then the height adjusting bolt 2 is tightened to make the compression cap 3 rise, and the distance between the compression cap 3 and the connecting base 12 is as small as possible, so as to achieve the purpose of clamping the sample, and after the bottom end of the sample is fixed, the stretching test is started; during the stretching test, the compression cap 3 is subjected to the upward tension of the main machine of the testing machine, and the flat tongs 1 clamp the sample fixed at the bottom end, at this time, the flat tongs 1 are subjected to a downward reaction force from the sample, so that the two flat tongs 1 have a tendency to move towards the central axis, so that the clamping force on the sample becomes tighter with the continuous stretching of the main machine of the testing machine, thereby improving the clamping effect and avoiding the sample from falling off.

[0021] During the compression test, the compression cap 3 is subjected to the downward pressure of the main machine of the testing machine, and the sample exerts a reaction force on the two flat tongs 1 to make the flat tongs 1 have a tendency to move to the sides, the height adjusting bolt 2 is tightened to fasten the compression cap 3, thereby limiting the movement of the flat tongs 1 and keeping the clamping force of the flat tongs 1 stable.

[0022] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0023] The above is only a preferred embodiment of the present application, and is not intended to limit the present application, and any slight modification, equivalent replacement and improvement made according to the technical essence of the present application to the above embodiments should be included in the protection scope of the technical scheme of the present application.

Claims

1. A mechanical fixture for tensile and compressive fatigue testing of materials, characterized in that, Includes buckle (8), fixing bolt (9), fixing base plate (11), base (12), pressure cap (3), fixing sleeve (5), fixing pin (10), and flat pliers (1); The buckle (8) is a frame structure with a buckle thread hole (7) on its upper and lower sides respectively. The upper end of the fixing bolt (9) is threaded to the buckle thread hole (7) on the lower side of the buckle (8) and is fastened by the set nut (6). The lower end of the fixed sleeve (5) is threaded to the top surface of the fixed base plate (11), and the bottom surface of the fixed base plate (11) is threaded to the base (12) through the fixed bolt (4); the inside of the pressure cap (3) is provided with an inverted trapezoidal groove that is shorter at the bottom and longer at the top, and two flat clamps (1) are set in the inverted trapezoidal groove. The pressure cap (3) is threaded to the connecting base (12) through the height adjustment bolt (2); The fixing sleeve (5) is fitted over the fixing bolt (9). The fixing bolt (9) and the fixing sleeve (5) are provided with transverse through holes at corresponding positions. The fixing pin (10) passes through the through holes to connect the fixing bolt (9) and the fixing sleeve (5).

2. The mechanical fixture for tensile and compressive fatigue testing of materials according to claim 1, characterized in that: After the fixing sleeve (5) is connected to the fixing bolt (9), the top of the fixing sleeve (5) abuts against the bottom of the buckle (8).

3. A mechanical fixture for tensile and compressive fatigue testing of materials according to claim 1, characterized in that: The height of the flat clamp (1) is greater than the height of the inverted trapezoidal groove.

4. A mechanical fixture for tensile and compressive fatigue testing of materials according to claim 1, characterized in that: The buckle (8) has an octagonal frame structure.

5. A mechanical fixture for tensile and compressive fatigue testing of materials according to claim 1, characterized in that: The contact surface between the flat clamp (1) and the inverted trapezoidal groove inside the pressure cap (3) is provided with grease.

Images