An auxiliary stretching device for a stretching machine and its working steps

Abstract

This invention relates to the field of tensile testing machine technology, specifically to an auxiliary tensile device for a tensile testing machine and its working steps, including a bending stress adjustment device, a hollow rotating device, a flat pushing mechanism, a preload sensor, and a controller; the bending stress adjustment device is used to automatically adjust the bending stress generated by the eccentric load on the lapped specimen; the hollow rotating platform is used to adjust the up-and-down movement of the clamping body; the flat pushing mechanism is used to realize the left-and-right movement of the jaws; the preload sensor (6) is used to detect the clamping force during the clamping process, and the controller controls the start and stop of the motor of the hollow rotating device (2) based on whether the detected clamping force reaches a preset value. The technical solution of this invention has the following advantages: high degree of automation, precise control of clamping force, ability to eliminate the bending stress generated by the lapped specimen, reduction of environmental noise, and improvement of working comfort.

Description

Technical Field

[0001] This invention relates to the field of tensile testing machine technology, and more specifically to an auxiliary tensile device for a tensile testing machine and its working steps. Background Technology

[0002] Tensile testing machines are mainly used for testing the mechanical properties of metallic and non-metallic materials. Depending on the shape and requirements of the test material, different specialized clamps are needed to clamp and position the specimen, assisting the tensile machine in completing the mechanical property test. Currently, for lap joint specimens in material bonding, existing clamps have the following shortcomings because the lap joint specimens are not on the same plane: 1. During the clamping process, eccentric loads can cause bending stress in the specimen, affecting the accuracy of the experimental results; 2. The clamping force of existing clamps cannot be automatically adjusted; 3. Existing hydraulic and pneumatic clamps may leak oil or air during use, and also generate noise, affecting the user's health. With the development of electrical and sensor technologies, a flat-push electric clamp that can automatically counteract bending stress and adjust and display the clamping force is proposed to achieve convenient, fast, and accurate tensile results. Summary of the Invention

[0003] The technical problem to be solved by this invention is to overcome the defects in the prior art, thereby providing an auxiliary stretching device for a stretching machine and its working steps, including a bending stress adjustment device, a hollow rotating device, a flat pushing mechanism, a preload sensor, a controller, and a display device; the bending stress adjustment device is used to automatically adjust the bending stress generated by the overlapping specimen; the hollow rotating platform is used to adjust the vertical movement of the clamping body; the flat pushing mechanism is used to realize the horizontal movement of the jaws; the preload sensor is used to detect the clamping force during the clamping process in real time, and the controller controls the start and stop of the motor of the hollow rotating device based on whether the detected clamping force reaches a preset value. This invention features a high degree of automation, precise control of the clamping force, elimination of bending stress generated by the overlapping specimen, reduction of environmental noise, and improved working comfort.

[0004] The specific technical solution adopted in this invention is as follows:

[0005] A bending stress adjustment device for a tensile testing machine is characterized by comprising a first connecting rod, a slide rail, a rolling structure, and a second connecting rod. The first connecting rod is used to connect the clamp to the force sensor connector on the tensile testing machine. The rolling structure is connected to the first connecting rod and installed on the slide rail. The second connecting rod is connected to the slide rail. The rolling structure and the slide rail cooperate to achieve adaptive adjustment of the bending stress generated when the lapped specimen is subjected to eccentric load, so that the specimen only bears axial tensile force.

[0006] The bending stress adjustment device also includes a cover plate and a set screw. The cover plate is used to seal the slide rail, and the set screw is used to fix the cover plate.

[0007] The rolling structure includes a rolling element, a connecting shaft, and a connecting plate, with the connecting shaft connected to both the rolling element and the connecting plate.

[0008] An electric auxiliary clamping device for a stretching machine is characterized by comprising a hollow rotating device, a flat pushing mechanism, a preload sensor, and a controller. The hollow rotating device is used to adjust the vertical movement of the clamp body. The hollow rotating device drives the flat pushing mechanism to realize the horizontal movement of the jaws. The preload sensor is used to detect the clamping force during the clamping process in real time. The controller controls the start and stop of the motor of the hollow rotating device based on whether the detected clamping force reaches a preset value.

[0009] The hollow rotating device includes a hollow rotating platform, a rotating sleeve, a clamping body, a limiting strip, a servo motor, a fastening screw, and a hollow screw. The hollow rotating platform is fixed to the flange on the third connecting rod of the flat pushing mechanism via the fastening screw, thus indirectly connecting the hollow rotating device to the body of the stretching machine. The rotating sleeve is fixed to the rotating device on the hollow rotating platform, and the rotating sleeve has a thread inside. A hollow screw is provided on the upper part of the clamping body, and the hollow screw engages with the thread inside the rotating sleeve. When the rotating sleeve rotates, it drives the hollow screw on the clamping body to rotate, thereby realizing the up and down movement of the clamping body. The limiting strip is used to fix the position of the clamping block of the flat pushing mechanism, and the servo motor is used to provide power to the rotating platform.

[0010] The pushing mechanism includes a third connecting rod, a slide rail, a clamping block, a spring, jaws, a baffle, and a flange. The third connecting rod passes through the hollow rotating device, and the slide rail is connected to the third connecting rod, while also providing guidance for the clamping block. The spring is installed in the middle of the clamping block to ensure that the clamping block fits against the inner surface of the clamping body. The jaws are used to clamp and fix the test specimen, and the baffle is used to fix the jaws and prevent them from moving back and forth.

[0011] The hollow rotating device drives the flat pushing mechanism to move the jaws left and right. Specifically, the clamping block is a wedge-shaped structure. When the clamping block moves up and down, the left and right movement of the jaws is achieved through the cooperation of the wedge-shaped clamping block and the slide, thereby making the specimen tighter and tighter and preventing the specimen from slipping.

[0012] The clamping device is equipped with a preload sensor, which sends the measured data to the controller, and the controller determines the magnitude of the clamping force based on the data from the preload sensor.

[0013] The pushing mechanism is connected to the bending stress adjustment device via a third connecting rod. The slider is connected to the third connecting rod, the clamping blocks are installed within the slider's track, a spring is installed between the two clamping blocks, and jaws are installed on the clamping blocks to clamp and fix the specimen. A baffle is installed on the clamping blocks to limit the movement of the jaws.

[0014] The display device is used to display the clamping force of the fixture, the speed of the servo motor, the adjustment of the clamping force, and the speed adjustment.

[0015] An auxiliary stretching device for a stretching machine includes the aforementioned bending stress adjustment device and the aforementioned electric auxiliary clamping device, wherein the electric auxiliary clamping device is connected to the second connecting rod of the bending stress adjustment device via a third connecting rod.

[0016] A working procedure for an electrically assisted clamping device, characterized by including a clamping process and a releasing process, wherein the clamping process specifically includes the following steps:

[0017] (1) System startup;

[0018] (2): Determine if the clamping button has been pressed. If yes, proceed to the next step; otherwise, return to step (1).

[0019] (3): The servo motor rotates forward, driving the hollow rotating device to rotate;

[0020] (4): The preload sensor (6) detects the clamping force during the clamping process;

[0021] (5): The controller determines whether the clamping force has reached the preset value of the preload force. If yes, proceed to the next step; otherwise, return to step (3).

[0022] (6): The servo motor stops working.

[0023] The loosening process includes:

[0024] (1): System startup;

[0025] (2): Determine if the release button has been pressed. If yes, proceed to the next step; otherwise, return to step (1).

[0026] (3): Servo motor reverses;

[0027] (4): After a 2-second delay, the servo motor stops working.

[0028] The technical solution of the present invention has the following advantages: (1) The bending stress adjustment device can automatically adjust the bending stress generated by the eccentric load on the lap joint specimen; (2) The hollow rotating platform is used to adjust the up and down movement of the clamp body, the flat pushing mechanism is used to realize the left and right movement of the jaws, the pre-tightening force sensor is used to detect the clamping force during the clamping process, and the controller controls the start and stop of the motor of the hollow rotating device based on whether the detected clamping force reaches the preset value. The hollow rotating platform drives the flat pushing mechanism, which has a high degree of automation and precise control of the clamping force; (3) The display device is used to display the clamping force of the clamp, the servo motor speed, the clamping force modification, and the speed adjustment, thereby improving the working comfort. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a three-dimensional structural diagram of an auxiliary stretching device for a stretching machine according to an embodiment of the present invention.

[0031] Figure 2(a) shows Figure 1 The diagram shows the overall structure of the bending stress adjustment device.

[0032] Figure 2(b) is a schematic diagram of the rolling structure of the bending stress adjustment device shown in Figure 2(a);

[0033] Figure 3 for Figure 1 The diagram shows the structure of the hollow rotating device.

[0034] Figure 4 for Figure 1 The diagram shows the structure of the horizontal pushing mechanism;

[0035] Figures 5(a) and 5(b) are flowcharts of the working steps of the electric auxiliary clamping device for the stretching machine in the embodiments of the present invention;

[0036] Explanation of reference numerals in the attached figures

[0037] 1-Bending stress adjustment device; 2-Hollow rotating device; 3-Pushing mechanism; 11-First connecting rod; 12-Slide rail; 13-Rolling structure; 14-Cover plate; 15-Set screw; 16-Second connecting rod; 17-Rolling element; 18-Connecting shaft; 19-Connecting plate; 21-Hollow rotating platform; 22-Rolling sleeve; 23-Clamping body; 24-Limiting strip; 25-Servo motor; 26-Fasting screw; 27-Hollow screw; 6-Sensor; 31-Third connecting rod; 32-Slider; 33-Clamping block; 34-Spring; 35-Jaws; 36-Baffle; 37-Flange. Detailed Implementation

[0038] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] Example 1

[0041] like Figure 1 An auxiliary stretching device for a stretching machine includes a bending stress adjustment device 1, an electric auxiliary clamping device comprising a hollow rotating device 2 and a flat pushing mechanism 3, a preload sensor, and a controller; the bending stress adjustment device 1 is used to automatically adjust the bending stress generated by the overlapping specimen; the hollow rotating device 2 is used to adjust the vertical movement of the clamping body 23; the flat pushing mechanism 3 is used to realize the horizontal movement of the jaws 35; and the controller is used to control the hollow rotating platform 21 and receive the clamping force detected by the sensor.

[0042] As shown in Figure 2(a), the first connecting rod 11 is used to connect the clamp to the sensor connector on the tensile machine. The rolling structure 13 is installed on the slide rail 12 to automatically adjust the bending stress generated when the lap specimen is subjected to eccentric load, so that the specimen only bears axial tension. The cover plate 14 is used to seal the slide rail 12, and the set screw 15 is used to fix the cover plate 14.

[0043] As shown in Figure 2(b), the rolling structure 13 includes a rolling element 17, a connecting shaft 18 and a connecting plate 19, with the connecting shaft 18 connected to the rolling element 17 and the connecting plate 19 respectively.

[0044] The working principle of the bending stress adjustment device is as follows: when the tensile machine applies tensile load to the lapped specimen, the lapped specimen will exhibit an eccentric load phenomenon. Under the action of the eccentric load, the rolling element 17 will move automatically on the slide rail 12 until the bending stress caused by the eccentric load is offset, thereby achieving the axial tensile effect of the specimen.

[0045] like Figure 3The hollow rotating device 2 includes a hollow rotating platform 21, a rotating sleeve 22, a clamping body 23, a limiting strip 24, a servo motor 25, a fastening screw 26 and a hollow screw 27, and a preload sensor 6. A third connecting rod 31 passes through the hollow screw 27 and connects to the second connecting rod 16. The hollow rotating platform 21 is fixed to the flange 37 on the third connecting rod 31 via the fastening screw, achieving an indirect connection between the hollow rotating device and the stretching machine body. The rotating sleeve 22 is fixed to the rotating device on the hollow rotating platform 21, and the rotating sleeve 22 has threads inside. The clamping body 23 has a hollow screw 27 on its upper part, which engages with the threads inside the rotating sleeve 22. When the rotating sleeve 22 rotates, it drives the hollow screw 27 on the clamping body 23 to rotate, thereby achieving the up-and-down movement of the clamping body. The limiting strip 24 is used to fix the position of the clamping block 33. The servo motor 25 provides power to the rotating platform. Furthermore, those skilled in the art can also use other mature power devices in the field to provide power to the hollow rotating platform 21.

[0046] like Figure 4 The pushing mechanism 3 includes a third connecting rod 31; a slider 32; a clamping block 33; a spring 34; jaws 35; a baffle 36; and a flange 37. The third connecting rod 31 is used to connect and fix with the second connecting rod 16. The slider 32 is threadedly connected to the third connecting rod 31 for easy assembly and to provide guidance for the clamping block 33. The spring 34 is installed in the middle of the clamping block 33 to ensure that the clamping block fits against the inner side of the clamping body 23. The jaws 35 are used to clamp and fix the overlapping specimens, and the baffle 36 is used to fix the jaws 35 to prevent them from moving back and forth.

[0047] The clamping working principle is as follows: When the hollow rotating platform 21 on the hollow rotating device 2 rotates forward, it drives the rotating sleeve 22 to rotate forward. The thread inside the rotating sleeve 22 drives the hollow screw 27 on the clamp body 23 to rotate, so the rotational motion is converted into the upward movement of the clamp body 23. While the clamp body 23 moves upward, it drives the wedge-shaped clamping block 33 to slide inward on the slide rail 32. While the clamping block 33 slides inward, it drives the jaws 35 to move inward, thereby achieving the clamping effect on the specimen. Under the action of the upward pulling force of the tensile machine, the specimen is pulled tighter and tighter, preventing the specimen from slipping.

[0048] The working principle of the release is as follows: When the hollow rotating platform 21 on the hollow rotating device 2 reverses, it drives the rotating sleeve 22 to reverse. The thread inside the rotating sleeve 22 drives the hollow screw 27 on the clamp body 23 to rotate, so the rotational motion is converted into the downward movement of the clamp body 23. While the clamp body 23 moves downward, under the action of the telescopic spring 34, it drives the wedge-shaped clamping block 33 to slide outward on the slide rail 32. While the clamping block 33 slides outward, it drives the jaws 35 to move outward, waiting for the next clamping of the specimen.

[0049] As shown in Figure 5, the working steps of the electric auxiliary clamping device for the tensile testing machine are as follows:

[0050] It includes a clamping process and a releasing process. The clamping process specifically includes the following steps:

[0051] (1) System startup;

[0052] (2): Determine whether the clamping button has been pressed. If yes, proceed to the next step; otherwise, return to step (1).

[0053] (3): The servo motor rotates forward, driving the hollow rotating device to rotate;

[0054] (4): The preload sensor (6) detects the clamping force during the clamping process;

[0055] (5): The controller determines whether the clamping force has reached the preset value of the preload force. If yes, proceed to the next step; otherwise, return to step (3).

[0056] (6): The servo motor stops working.

[0057] The loosening process includes:

[0058] (1): System startup;

[0059] (2): Determine if the release button has been pressed. If yes, proceed to the next step; otherwise, return to step (1).

[0060] (3): Servo motor reverses;

[0061] (4): After a 2-second delay, the servo motor stops working.

[0062] The technical solution of this invention has the following advantages: high degree of automation, precise control of clamping force, elimination of bending stress generated by overlapping specimens, reduction of environmental noise, and improvement of working comfort.

[0063] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An auxiliary stretching device for a stretching machine, comprising a bending stress adjustment device and an electric auxiliary clamping device, the electric auxiliary clamping device being connected with the second connecting rod (16) of the bending stress adjustment device through a third connecting rod (31); the bending stress adjustment device comprises a first connecting rod (11), a sliding rail (12), a rolling structure (13), a cover plate (14), a locking screw (15) and a second connecting rod (16), the first connecting rod (11) is used to connect the bending stress adjustment device with a force sensor joint on the stretching machine, the rolling structure (13) is connected with the first connecting rod (11) and placed into the sliding rail (12), the second connecting rod (16) is connected with the sliding rail (12), the rolling structure (13) cooperates with the sliding rail (12) to realize self-adaptive adjustment of the bending stress generated when the lapped test piece is subjected to eccentric load, so that the test piece only bears axial tension; the self-adaptive adjustment is that the rolling body (17) is driven to move automatically in the sliding rail (12) under the action of the eccentric load until the bending stress generated due to the lapped test piece subjected to the eccentric load is offset; the cover plate (14) is used for sealing the sliding rail (12), and the locking screw (15) is used for fixing the cover plate (14); the rolling structure (13) comprises a rolling body (17), a connecting shaft (18) and a connecting plate (19), the connecting shaft (18) is connected with the rolling body (17) and the connecting plate (19) respectively; the rolling body (17) is four symmetrical rolling bearings, the connecting shaft (18) is two, the two ends of one connecting shaft are connected with two rolling bearings, and the two ends of the other connecting shaft are connected with the other two rolling bearings, the rolling bearings are placed in the symmetrical notches on the upper and lower surfaces of the sliding rail (12), and the notches are open long notches; the electric auxiliary clamping device comprises a hollow rotating device (2), a flat push mechanism (3), a pre-tightening force sensor (6) and a controller, the hollow rotating device (2) is used to adjust the up-down movement of a clamping body (23), the hollow rotating device (2) drives the flat push mechanism (3) to realize the left-right movement of a jaw (35), the pre-tightening force sensor (6) is used to detect the clamping force in real time during clamping, and the controller controls the start-stop of the motor of the hollow rotating device (2) based on whether the detected clamping force reaches a preset value. The hollow rotating device (2) comprises a hollow rotating platform (21), a rotating sleeve (22), a clamping body (23), a limiting strip (24), a servo motor (25), a fastening screw rod (26) and a hollow screw rod (27); the hollow rotating platform (21) is fixed with the flange plate (37) on the third connecting rod (31) of the flat-pushing mechanism (3) through the fastening screw rod (26), so as to indirectly connect the hollow rotating device (2) with the body of the stretching machine; the rotating sleeve (22) is fixed with the rotating device on the hollow rotating platform (21), and the rotating sleeve (22) is provided with threads in the cylinder; the hollow screw rod (27) is arranged on the upper portion of the clamping body (23) and cooperates with the threads in the rotating sleeve (22); when the rotating sleeve (22) rotates, the hollow screw rod (27) on the clamping body (23) rotates, so that the clamping body (23) moves up and down; the limiting strip (24) is used for fixing the position of the clamping block (33) of the flat-pushing mechanism (3); and the servo motor (25) is used for providing power for the rotating platform.

2. The auxiliary stretching device for the stretching machine according to claim 1, wherein the flat-pushing mechanism (3) comprises a third connecting rod (31), a slide (32), a clamping block (33), a spring (34), a jaw (35), a baffle (36) and a flange plate (37); the third connecting rod (31) passes through the hollow rotating device (2); the slide (32) is connected with the third connecting rod (31) and provides a guide for the clamping block (33); the spring (34) is arranged in the middle of the clamping block (33), so as to ensure that the clamping block (33) is attached to the inner side of the clamping body (23); the jaw (35) is used for clamping and fixing the test sample; and the baffle (36) is used for fixing the jaw (35) and preventing the jaw (35) from moving back and forth.

3. The auxiliary stretching device for the stretching machine according to claim 2, wherein the hollow rotating device (2) drives the flat-pushing mechanism (3) to move the jaw (35) left and right, and the clamping block (33) is in a wedge-shaped structure; when the clamping body (23) moves up and down, the jaw (35) moves left and right through the cooperation of the wedge-shaped clamping block (33) and the slide (32), so that the test sample is stretched more tightly, and the test sample is prevented from slipping off.

4. A working step applied to the auxiliary stretching device for a stretching machine according to claim 1, characterized in that: The method comprises a clamping process and a loosening process, wherein the clamping process specifically comprises the following steps: (1) System starts; (2) Determine whether the clamping button is pressed, if yes, proceed to the next step; if no, return to step (1); (3) The servo motor rotates forward to drive the hollow rotating device to rotate; (4) The pre-tightening force sensor (6) detects the clamping force in the clamping process; (5) The controller determines whether the clamping force reaches the pre-tightening force preset value, if yes, proceed to the next step; if no, return to step (3); (6) The servo motor stops working.

5. The working steps of claim 4, characterized in that: The loosening process comprises: (1) System starts; (2) Determine whether the loosening button is pressed, if yes, proceed to the next step; if no, return to step (1) (3) The servo motor reverses; (4) Delay for 2 seconds, and the servo motor stops working.

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