A device for testing the strength of a chisel connection

Abstract

The utility model discloses a wood chisel connecting strength testing arrangement relates to wood chisel production equipment technical field, including frame, fixed clamp and detection mechanism. Fixed clamp is equipped with the positioning base of taking profiled location groove and clamping mechanism, is used for accurate fixed wood chisel rod department. Detection mechanism includes coaxial composite loading mechanism, wherein the tensile force output end of axial tension module is nested in the hollow torque output end inside of circumferential torque module, and both are coupled through spline pair and are connected, and common drive power composite chuck. The utility model discloses hollow rotor torque motor realizes torque output, provides axial tension through servo motor and ball screw, can synchronous or independent exertion pull twist composite load, and the actual working condition of wood chisel is truly simulated. The device solves the problems that traditional testing method can not simulate composite stress, clamping is unstable, testing efficiency is low etc.

Description

Technical Field

[0001] This utility model relates to the technical field of wood chisel production equipment, and in particular to a wood chisel connection strength testing device. Background Technology

[0002] As a key tool in both traditional and modern woodworking, the structural reliability of a wood chisel directly affects its safety and lifespan. Wood chisels are typically constructed by connecting a metal shaft to a wooden or plastic handle using processes such as interference fit, gluing, or metal ring crimping. During actual operation, the connection point needs to withstand complex combined loads, including axial tension, circumferential torque, and the coupling effect between the two. Therefore, accurately assessing the mechanical properties of the wood chisel's connection points is crucial for product quality control.

[0003] Currently, the industry typically uses general-purpose testing equipment to perform individual tests on the strength of these tools. For example, a tensile testing machine is used to test the axial tensile strength of the handle, or a torque wrench is used to test the torsional strength. While these methods can obtain basic mechanical parameters, they have significant limitations: the testing process requires multiple sample clamping operations and cannot simulate the complex stress states commonly encountered in actual use, leading to a large deviation between the test results and real-world working conditions.

[0004] Furthermore, existing testing devices often feature simple fixture designs, frequently employing general-purpose V-blocks or flat-jaw pliers for fixation. These fixtures are poorly suited for the handles of wooden chisels, especially irregularly shaped chisels, and are prone to slippage, rotation, or stress concentration during testing, further affecting the accuracy and reliability of the test data. Simultaneously, the separate testing equipment leads to low testing efficiency, making it difficult to meet the quality control requirements of modern production. Therefore, developing a wooden chisel connection strength testing device that can realistically simulate actual stress conditions, has dedicated fixtures, and is easy to operate is particularly necessary. Utility Model Content

[0005] Purpose of the Invention: The purpose of this invention is to provide a device for testing the joint strength of wooden chisels, addressing the problems of existing technologies being unable to accurately simulate the combined tensile and torsional loads experienced by wooden chisels during use, as well as low testing accuracy and efficiency. This invention, through a coaxial composite loading mechanism and a dedicated fixture, achieves precise and efficient testing of the joints of wooden chisels under composite stress, effectively improving the reliability and accuracy of the test results.

[0006] Technical solution:

[0007] A wood chisel joint strength testing device includes a frame, a fixing fixture, and a testing mechanism. The fixing fixture is disposed at one end of the frame, and the testing mechanism is disposed at the other end of the frame. The testing mechanism includes an axial tensile force module, a circumferential torque module, and a power-composite moving chuck. The axial tensile force module includes a first drive source and an axially movable tensile force output end, the tensile force output end being rotatably connected to the first drive source, and the power-composite moving chuck being fixedly connected to the tensile force output end. The circumferential torque module includes a second drive source and a rotating torque output end. The torque output end is a hollow structure that is loosely fitted outside the tensile force output end, and the tensile force output end and the torque output end are connected through a coupling structure.

[0008] Furthermore, the first drive source includes a servo motor, a ball screw, and a moving seat, and the tension output end is a pulling block; the ball screw is connected to the output shaft of the servo motor; the moving seat is fixedly connected to the nut of the ball screw, and the moving seat is rotatably connected to the pulling block.

[0009] Furthermore, the second drive source is a hollow rotor torque motor; the stator of the hollow rotor torque motor is fixed on the frame; the rotor of the hollow rotor torque motor serves as the torque output end.

[0010] Furthermore, the coupling structure is a spline pair; the spline pair includes an external spline disposed on the outside of the tensile output end and an internal spline disposed on the inside of the torque output end.

[0011] Furthermore, the power compound chuck is a three-jaw chuck.

[0012] Furthermore, the fixing fixture includes a positioning base and a clamping mechanism. The positioning base is provided with a contour positioning groove. The clamping mechanism is located above the positioning base and is used to press and fix the rod of the wood chisel into the contour positioning groove.

[0013] Furthermore, the clamping mechanism includes a cylinder and a pressure rod.

[0014] Beneficial effects:

[0015] 1. Through an innovative coaxial composite loading mechanism design, the axial tension module and the circumferential torque module are integrated into one unit. This allows for the synchronous or programmed application of axial tension and circumferential torque to the wood chisel connection points, realistically simulating the most demanding composite stress conditions in actual use. This testing method enables the test results to more accurately reflect the connection reliability of the product in actual use, greatly improving the effectiveness and practicality of the test.

[0016] 2. By employing a servo motor and a hollow rotor torque motor as the drive source, combined with ball screw and spline pair transmission, precise digital control and stable output of tensile and torsional loads are achieved. During testing, there is no need to change equipment or re-clamp samples; composite load testing can be completed with a single setup. This effectively eliminates systematic errors and repetitive positioning errors in step-by-step testing, significantly improving the accuracy and repeatability of test data, while also greatly enhancing testing efficiency.

[0017] 3. The fixing fixture adopts a design combining a base with a contoured positioning groove and a clamping mechanism, which effectively restricts the displacement freedom of the chisel head and prevents the sample from slipping or deflecting during the test. Combined with the powerful composite chuck's firm grip on the handle, this forms a complete constraint system, ensuring that the test load is accurately applied to the connection point under test, thus guaranteeing reliable test data.

[0018] 4. The entire testing mechanism has a compact and reasonable layout, and the innovative application of the hollow rotor torque motor effectively solves the problem of spatial interference. Combined with a corresponding control system, it enables programmed control of the loading process and automatic data acquisition, reducing the technical requirements and labor intensity for operators, and making the testing process more standardized and convenient. Attached Figure Description

[0019] Figure 1 This is a three-dimensional representation of the present invention. Figure 1 ;

[0020] Figure 2 This is a three-dimensional representation of the present invention. Figure 2 ;

[0021] Figure 3 This is an enlarged view of the position of the fixing clamp of this utility model;

[0022] Figure 4 This is an enlarged view of the location of the testing mechanism of this utility model. Detailed Implementation

[0023] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1

[0025] like Figure 1-4As shown, a wood chisel connection strength testing device includes a frame 1, a fixing clamp 2, and a testing mechanism 3. The fixing clamp 2 is disposed at one end of the frame 1; the testing mechanism is disposed at the other end of the frame 1. The testing mechanism 3 includes an axial tensile force module 31, a circumferential torque module 32, and a power composite chuck 33. The axial tensile force module 31 includes a first drive source 311 and an axially movable tensile force output end 312. The tensile force output end 312 is rotatably connected to the first drive source 311, and the power composite chuck 33 is fixedly connected to the tensile force output end 312. The circumferential torque module 32 includes a second drive source 321 and a rotationally output torque output end 322. The torque output end 322 is a hollow structure that is loosely fitted outside the tensile force output end 312. The tensile force output end 312 and the torque output end 322 are connected by a coupling structure 34. The coaxial composite loading structure is the core innovation of this device. By nesting the tensile output end inside the torque output end, it enables the simultaneous transmission of two different types of loads within a limited space, effectively simulating the tensile and torsional combined stress conditions that a wooden chisel may encounter in actual use.

[0026] Furthermore, the first drive source 311 includes a servo motor 3111, a ball screw 3112, and a moving base 3113. The tension output end 312 is a pulling block. The ball screw 3112 is connected to the output shaft of the servo motor 3111. The moving base 3113 is fixedly connected to the nut of the ball screw 3112, and the moving base 3113 is rotatably connected to the pulling block. This design cleverly converts the rotational motion of the servo motor into high-precision linear motion through the ball screw pair. At the same time, the bearing connection ensures that the tension module does not interfere with the operation of the torque module when transmitting axial tension, thus achieving mechanical decoupling of the two load transmission paths.

[0027] Furthermore, the second drive source 321 is a hollow rotor torque motor; the stator of the hollow rotor torque motor is fixed to the frame 1; the rotor of the hollow rotor torque motor serves as the torque output end 322. This special structure of the hollow rotor is a key design feature of this device. Its internal through-holes provide a complete passageway for the tension output end and its transmission components, achieving perfect spatial nesting of the two power units. This not only significantly saves installation space but also simplifies the transmission chain and improves the system's rigidity and response speed.

[0028] Furthermore, the coupling structure 3434 is a spline pair; the spline pair includes an outer spline 341 disposed on the outside of the tensile output end 312 and an inner spline 342 disposed on the inside of the torque output end 322. The spline pair here plays a crucial role in dynamic coupling and decoupling: when axial tensile force is applied, the outer spline 341 can slide freely within the inner spline 342, ensuring smooth force transmission; when torque is applied, the meshing surfaces of the inner and outer splines efficiently transmit the torque to the pulling block. This design ensures that tensile and torque loads can be applied independently or synchronously in any proportion, providing a technical basis for accurately simulating complex working conditions.

[0029] Furthermore, the power-driven composite chuck 33 is a three-jaw chuck. Three-jaw chucks are a commonly used clamping method in the prior art, and will not be described in detail here.

[0030] Furthermore, the fixing fixture 2 includes a positioning base 21 and a clamping mechanism 22. The positioning base 21 is provided with a contour positioning groove 211; the clamping mechanism 22 is disposed above the positioning base 21 and is used to press and fix the rod of the wooden chisel into the contour positioning groove 211. This contour design achieves multi-degree-of-freedom constraint on the chisel head through surface contact, effectively limiting the rotation and translation of the chisel head during testing, ensuring that the applied load is accurately applied to the connection part to be tested rather than being absorbed by the fixture.

[0031] Furthermore, the clamping mechanism 22 includes a cylinder 221 and a pressure rod 222. The cylinder is a double-acting compact cylinder, and its action is controlled by a solenoid valve. The test data acquisition of this invention is based on sensors within the drive source. The control system acquires the drive current of the servo motor 3111 in real time, and, combined with the motor torque constant, ball screw lead, and transmission system efficiency parameters, calculates and displays the axial tension value in real time using an established mechanical model. Simultaneously, it acquires the position signal from the servo motor encoder 3115 to accurately calculate the axial displacement data. For torque detection, the control system directly acquires the drive current of the torque motor 321, combines it with its torque constant to directly obtain the output torque value, and obtains the rotation angle through its built-in encoder 3213. This detection scheme based on sensors within the drive source ensures measurement accuracy while eliminating the need for external force sensors, significantly simplifying the mechanical structure, reducing manufacturing costs, and improving system reliability.

[0032] During testing, the control system can control the working state of the two drive sources according to a preset program, realizing various test modes such as constant rate loading, constant load holding, and cyclic loading. In operation, the wood chisel handle is first placed in the contour positioning groove 211, and the cylinder 221 drives the pressure rod 222 to press and fix it; then, the power compound chuck 33 automatically clamps the wood chisel handle. After the test begins, the control system independently or synchronously controls the servo motor 3111 and the hollow rotor torque motor 321 to work, applying axial tension and circumferential torque to the wood chisel handle through the ball screw 3112 and spline pair 34 respectively, comprehensively evaluating the mechanical performance of the wood chisel connection under different working conditions. When the load reaches the set threshold or the wood chisel connection fails, the system automatically stops and records the peak data, completing the test.

[0033] The embodiments described above are merely illustrative of certain implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A device for testing the joint strength of wooden chisels, characterized in that, The device includes a frame (1), a fixing fixture (2), and a detection mechanism (3). The fixing fixture (2) is located at one end of the frame (1). The detection mechanism is located at the other end of the frame (1). The detection mechanism (3) includes an axial tension module (31), a circumferential torque module (32), and a power compound moving chuck (33). The axial tension module (31) includes a first drive source (311) and an axially movable tension output end (312). The tension output end (312) is rotatably connected to the first drive source (311), and the power compound moving chuck (33) is fixedly connected to the tension output end (312). The circumferential torque module (32) includes a second drive source (321) and a rotationally output torque output end (322). The torque output end (322) is a hollow structure that is loosely fitted outside the tension output end (312). The tension output end (312) and the torque output end (322) are connected by a coupling structure (34).

2. The wood chisel connection strength testing device according to claim 1, characterized in that, The first drive source (311) includes a servo motor (3111), a ball screw (3112), and a moving seat (3113). The tension output end (312) is a pulling block. The ball screw (3112) is connected to the output shaft of the servo motor (3111). The moving seat (3113) is fixedly connected to the nut of the ball screw (3112), and the moving seat (3113) is rotatably connected to the pulling block.

3. The wood chisel connection strength testing device according to claim 1, characterized in that, The second drive source (321) is a hollow rotor torque motor; the stator of the hollow rotor torque motor is fixed on the frame (1); the rotor of the hollow rotor torque motor serves as the torque output end (322).

4. The wood chisel connection strength testing device according to claim 1, characterized in that, The coupling structure (34) is a spline pair; the spline pair includes an outer spline (341) disposed on the outside of the tensile output end (312) and an inner spline (342) disposed on the inside of the torque output end (322).

5. The wood chisel connection strength testing device according to claim 1, characterized in that, The power composite chuck (33) is a three-jaw chuck.

6. The wood chisel connection strength testing device according to claim 1, characterized in that, The fixing fixture (2) includes a positioning base (21) and a clamping mechanism (22). The positioning base (21) is provided with a contour positioning groove (211). The clamping mechanism (22) is located above the positioning base (21) and is used to press and fix the rod of the wood chisel into the contour positioning groove (211).

7. The wood chisel connection strength testing device according to claim 6, characterized in that, The clamping mechanism (22) includes a cylinder (221) and a pressure rod (222).

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