Testing Machine

Abstract

The embodiment of the present invention provides a testing machine for detecting the self-tapping performance of medical screws, the testing machine comprises a frame, a first driving assembly, a second driving assembly, an elastic member and a counterweight assembly; the first driving assembly is connected to the frame, the second driving assembly is slidably connected to the frame, the elastic member is located between the first driving assembly and the second driving assembly and can simultaneously abut against the first driving assembly and the second driving assembly; the counterweight assembly is connected to the frame and is used to balance the gravity of the second driving assembly so that the elastic member is in a natural state; the first driving assembly is used to drive the elastic member to move so that the elastic member is compressed and drives the second driving assembly away from the first driving assembly; the second driving assembly is used to drive the medical screw to be tested to rotate. The measurement result of the testing machine has a small error and high accuracy.

Description

Technical Field

[0001] The present invention relates to the field of testing equipment, and in particular to a testing machine. Background Art

[0002] The self-tapping performance of medical screws is a very important performance indicator. The general reference test standard is ASTM F543-A4, which is to increase the axial load pressure of the medical screw at a constant rate.

[0003] The study found that the existing testing equipment for testing the self-tapping performance of medical screws has the following shortcomings:

[0004] The test results have large errors. Summary of the invention

[0005] The objects of the present invention include, for example, providing a testing machine that can reduce the error of the self-tapping performance test results of medical screws and improve the accuracy of the test results.

[0006] The embodiments of the present invention can be implemented as follows:

[0007] In a first aspect, an embodiment of the present invention provides a testing machine for detecting the self-tapping performance of a medical screw, the testing machine comprising:

[0008] A frame, a first drive assembly, a second drive assembly, an elastic member and a counterweight assembly; the first drive assembly is connected to the frame, the second drive assembly is slidably connected to the frame, the elastic member is located between the first drive assembly and the second drive assembly and can simultaneously abut against the first drive assembly and the second drive assembly; the counterweight assembly is connected to the frame and is used to balance the gravity of the second drive assembly so that the elastic member is in a natural state; the first drive assembly is used to drive the elastic member to move so that the elastic member is compressed and drives the second drive assembly away from the first drive assembly; the second drive assembly is used to drive the medical screw to be tested to rotate.

[0009] In an optional embodiment, the elastic member includes a spring, the spring is located between the first drive assembly and the second drive assembly, and both ends of the spring can abut against the first drive assembly and the second drive assembly at the same time.

[0010] In an optional embodiment, the elastic member is connected to the first drive assembly and the second drive assembly respectively.

[0011] In an optional embodiment, the first driving assembly includes a telescopic structure connected to the frame and used to drive the elastic member to move closer to or away from the second driving assembly.

[0012] In an optional embodiment, the second driving assembly includes a motor and a sliding member, the sliding member is slidably matched with the frame, the motor is connected to the sliding member, and the motor is used to drive the screw to be tested to rotate; the elastic member can be supported on the sliding member.

[0013] In an optional embodiment, a guide member is provided on the frame, and the sliding member is slidably matched with the guide member.

[0014] In an optional embodiment, the second drive assembly further includes a clamp, which is connected to the output shaft of the motor and is used to clamp the screw to be tested.

[0015] In an optional embodiment, the counterweight assembly includes a pull wire, a pulley block and a counterweight block, the pulley block is connected to the frame, the pull wire is wound around the pulley block, one end of the pull wire is connected to the second drive assembly, and the other end of the pull wire is connected to the counterweight block.

[0016] In an optional embodiment, the counterweight assembly further includes a bearing member, the bearing member is slidably connected to the frame, the pull wire is connected to the bearing member, and the counterweight block is placed on the bearing member.

[0017] In an optional embodiment, the testing machine further includes a first sensor and a second sensor, wherein the first sensor is used to detect the pressure exerted by the first drive assembly on the screw to be tested; and the second sensor is used to detect the torque exerted by the second drive assembly on the screw to be tested.

[0018] The beneficial effects of the embodiments of the present invention include, for example:

[0019] In summary, this embodiment provides a test machine. During the test, the stiffness of the system composed of the test machine and the object to be tested has a greater impact on the test results. The stiffness of the first drive assembly is set to K1, the stiffness of the second drive assembly is set to K2, and the stiffness of the combined structure of the medical screw and the simulated bone block to be tested is set to K3. It should be understood that during the test, the test machine needs to provide a stable axial pressure for the medical screw. Therefore, the stiffness of the first drive assembly and the second drive assembly is relatively large to ensure that radial and axial deformations are not likely to occur during the test. Therefore, the values ​​of K1 and K2 are much larger than the value of K3. The overall stiffness of the test system without elastic parts is K0=1 / (1 / K1+1 / K2+1 / K3). The result of K0 is approximately equal to K3. When at least one of the medical screw and the simulated bone block changes, the overall stiffness of the system will change, and the impact is relatively large. When the performance of the medical screw is tested using a test device without elastic parts, the PID value of the test device needs to be adjusted according to the operator's experience in view of the continuous changes in the medical screw and the simulated bone block to achieve an ideal control effect. Therefore, when the test equipment without elastic parts is used, the adjustment effect is different due to different operators, which eventually leads to large error in the test results and poor accuracy. The existing test equipment does not use elastic parts, resulting in large measurement errors and poor accuracy. The test machine provided in this embodiment includes an elastic part, and the rigidity of the elastic part is set to K4. The rigidity of the elastic part is much smaller than the values ​​of K1, K2 and K3. The rigidity of the entire test system K0′=1 / (1 / K1+1 / K2+1 / K3+1 / K4), and the result of K0′ is approximately equal to K4, that is, when different medical screws and simulated bone blocks are replaced to perform corresponding tests, since the elastic part does not change, the rigidity of the system will not change significantly, and there is no need to debug the system, which reduces the difficulty of the test and improves the accuracy of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A schematic diagram of the structure of the test machine provided by this embodiment from a first perspective;

[0022] Figure 2 A schematic diagram of the structure of the test machine provided in this embodiment from a second perspective.

[0023] icon:

[0024] 001-testing machine; 002-medical screw; 003-simulated bone block; 100-frame; 110-base; 120-column; 130-crossbeam; 140-fixed plate; 150-guide member; 200-first drive assembly; 210-axial motor; 220-pressing plate; 300-second drive assembly; 310-motor; 320-sliding plate; 330-clamp; 400-elastic member; 500-counterweight assembly; 510-pull wire; 520-pulley block; 530-counterweight block; 540-bearing member; 600-first sensor; 700-second sensor. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0028] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0029] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0030] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0031] This embodiment provides a testing machine 001, which is suitable for testing the self-tapping performance of a medical screw 002, and specifically, for testing the axial load force of the medical screw 002. The performance parameters of the medical screw 002 measured by the testing piece have small errors and are accurate and reliable.

[0032] In this embodiment, please refer to Figure 1 and Figure 2 , Figure 1 The schematic diagram of the structure of the test machine 001 from the first perspective is shown. Figure 2 The schematic diagram of the structure of the test machine 001 from the second perspective is shown. The test machine 001 includes a frame 100, a first drive assembly 200, a second drive assembly 300, an elastic member 400 and a counterweight assembly 500; the first drive assembly 200 is connected to the frame 100, the second drive assembly 300 is slidably connected to the frame 100, the elastic member 400 is located between the first drive assembly 200 and the second drive assembly 300 and can simultaneously abut against the first drive assembly 200 and the second drive assembly 300; the counterweight assembly 500 is connected to the frame 100, and is used to balance the gravity of the second drive assembly 300, so that the elastic member 400 is in a natural state, wherein the natural state refers to the elastic member 400 being in a state of not being stretched or compressed; the first drive assembly 200 is used to drive the elastic member 400 to move, so that the elastic member 400 is compressed and drives the second drive assembly 300 away from the first drive assembly 200; the second drive assembly 300 is used to drive the medical screw 002 to be tested to rotate.

[0033] It should be noted that the test machine 001 provided in this embodiment is placed vertically when in use, and the first drive assembly 200, the elastic member 400, the second drive assembly 300, the medical screw 002 and the simulated bone block 003 are arranged in sequence from top to bottom. Before the test device is operated, the counterweight assembly 500 needs to be adjusted so that the counterweight assembly 500 balances the gravity of the second drive assembly 300, so that the elastic member 400 located between the first drive assembly 200 and the second drive assembly 300 is in a natural state, and then the first drive assembly 200 and the second drive assembly 300 can be started for testing. The first driving component 200 provides an axial force, pressing the elastic member 400 to deform the elastic member 400 and generate an elastic force. The axial force of the first driving component 200 is first converted into an elastic force, and then the second driving component 300 is driven to slide downward by the elastic force. At the same time, the second driving component 300 provides a torque for the medical screw 002 installed thereon. The medical screw 002 is screwed into the simulated bone block 003 through the joint action of the first driving component 200 and the second driving component 300.

[0034] During the test, the stiffness of the system composed of the test machine 001 and the object to be tested has a great influence on the test results. The stiffness of the first drive assembly 200 is set to K1, the stiffness of the second drive assembly 300 is set to K2, and the stiffness of the combined structure of the medical screw 002 and the simulated bone block 003 to be tested is set to K3. It should be understood that during the test, the test machine 001 needs to provide a stable axial pressure for the medical screw 002. Therefore, the stiffness of the first drive assembly 200 and the second drive assembly 300 is relatively large to ensure that radial and axial deformation is not likely to occur during the test. Therefore, the values ​​of K1 and K2 are much larger than the value of K3. The overall stiffness of the test system without the elastic member 400 is K0=1 / (1 / K1+1 / K2+1 / K3). The result of K0 is approximately equal to K3. When at least one of the medical screw 002 and the simulated bone block 003 changes, the overall stiffness of the system will change, and the impact is relatively large. When the performance of the medical screw 002 is tested using a test device without the elastic member 400, the PID value of the test device needs to be adjusted based on the operator's experience in order to achieve an ideal control effect in view of the constantly changing conditions of the medical screw 002 and the simulated bone block 003. Therefore, when the test device without the elastic member 400 is used, the adjustment effect is different due to different operators, which ultimately leads to large errors in the test results and poor accuracy. However, the existing test devices do not use the elastic member 400. When at least one of the medical screw 002 or the simulated bone block 003 is changed, the influence on the system stiffness is large, and the operator needs to adjust the PID value based on experience, which leads to large measurement errors and poor accuracy. The test machine 001 provided in this embodiment includes an elastic member 400, and the stiffness of the elastic member 400 is set to K4. The stiffness of the elastic member 400 is much smaller than the values ​​of K1, K2 and K3. The overall stiffness of the test system is K0′=1 / (1 / K1+1 / K2+1 / K3+1 / K4), and the result of K0′ is approximately equal to K4. That is, when different medical screws 002 and simulated bone blocks 003 are replaced to perform corresponding tests, since the elastic member 400 does not change, the stiffness of the system will not change significantly, and there is no need to debug the system, which reduces the difficulty of the test and improves the accuracy of the test results.

[0035] It should be noted that the above calculation formula involves the stiffness calculation formula of the system after the springs are connected in series, as follows:

[0036] When two springs are connected in series, assuming that the springs are subjected to a tensile force F, the elongation of the first spring is L1 = F / K1, and the elongation of the second spring is L2 = F / K2. The total elongation L = (F / K1 + F / K2), and the new stiffness coefficient (rigidity coefficient) is K = F / L = 1 / (1 / K1 + 1 / K2).

[0037] Optionally, the frame 100 includes a base 110, two columns 120, a crossbeam 130 and a fixing plate 140, wherein the base 110 is horizontally arranged, the two columns 120 are arranged in parallel and spaced apart and are both connected to the base 110, the crossbeam 130 is fixedly connected to both columns 120, and the fixing plate 140 is fixedly connected to the crossbeam 130. A surface of the base 110 facing the fixing plate 140 is used to place a simulated bone block 003 that matches the medical screw 002 to be tested. The simulated bone block 003 may be provided with a hole for the medical screw 002 to penetrate.

[0038] Furthermore, the frame 100 further includes a guide member 150 , which may be a cylindrical rod. The guide member 150 is fixedly connected to the fixing plate 140 , and the guide member 150 is parallel to the column 120 .

[0039] Optionally, the elastic member 400 includes a spring, and the spring has a strong deformation capacity, that is, the stiffness of the spring is small, the reciprocal value of the spring stiffness is large, and the stiffness of the entire test system is more stable. The two ends of the spring are connected to the first drive assembly 200 and the second drive assembly 300 at the same time. When the spring is arranged vertically, a certain tensile deformation occurs under its own weight. In order to improve the accuracy of the test results, during the test, it is necessary to adjust the counterweight assembly 500 to make the spring in a natural state. The counterweight assembly 500 needs to balance the gravity of the second drive assembly 300 and the gravity of the spring at the same time, so that the spring located between the first drive assembly 200 and the second drive assembly 300 is neither stretched nor compressed, and is in a natural state without stored elastic force. When the first drive assembly 200 provides an axial force, the elastic force generated by the spring is equal to the axial force, thereby improving the accuracy of the test results.

[0040] In other embodiments, the elastic member 400 may include a rubber pad. In addition, the elastic member 400 is disposed between the first drive assembly 200 and the second drive assembly 300. During the test, the two opposite sides of the elastic member 400 can abut against the first drive assembly 200 and the second drive assembly 300 at the same time, and the elastic member 400 may not be connected to the first drive assembly 200 and the second drive assembly 300.

[0041] In this embodiment, the first drive assembly 200 provides an axial force for the elastic member 400, so that the elastic member 400 is compressed to generate a downward thrust, pushing the second drive assembly 300 to move. The first drive assembly 200 may include a telescopic structure, for example, in this embodiment, the first drive assembly 200 includes an axial motor 210. Alternatively, in other embodiments, the first drive assembly 200 includes a cylinder, a hydraulic cylinder, a gear rack transmission mechanism, or a screw transmission structure.

[0042] Furthermore, the first driving assembly 200 further includes a pressing plate 220, which is used to press the elastic member 400, so that the force of the elastic member 400 is more balanced, and the elastic force of the elastic member 400 is basically in the vertical direction, and it is not easy to generate a component force in a direction having an angle with the vertical direction, thereby improving the accuracy of the test result. The pressing plate 220 is slidably connected to the guide member 150.

[0043] In this embodiment, the second driving assembly 300 provides a torque for the medical screw 002 to be tested, that is, it can drive the medical screw 002 installed on the second driving assembly 300 to rotate, and then screw it onto the simulated bone block 003. Optionally, the second driving assembly 300 includes a motor 310, which is slidably connected to the frame 100 and can reciprocate along the height direction of the frame 100 under the cooperation of the first driving assembly 200 and the elastic member 400.

[0044] Further, the second driving assembly 300 includes a sliding member, which may be a sliding plate 320, and a guide hole is provided on the sliding plate 320. The motor 310 is connected to the sliding plate 320, and the sliding plate 320 is slidably connected to the frame 100. In other words, the guide hole on the sliding plate 320 is slidably matched with the guide member 150, the guide member 150 is inserted into the guide hole, and the sliding plate 320 can reciprocate along the axial direction of the guide member 150. It should be noted that the number of the guide holes on the sliding plate 320 can be one or more. When the number of the guide holes is multiple, the number of the guide members 150 is also multiple, and the multiple guide members 150 are slidably matched with the multiple guide holes in a one-to-one correspondence.

[0045] Furthermore, the second driving assembly 300 further includes a clamp 330, which is connected to the output shaft of the motor 310, and is used to clamp the medical screw 002, and the medical screw 002 rotates together with the output shaft under the drive of the motor 310. The clamp 330 may be a three-jaw clamp.

[0046] In this embodiment, the counterweight assembly 500 includes a cable 510, a pulley block 520 and a counterweight block 530, the pulley block 520 is connected to the frame 100, the cable 510 is wound around the pulley block 520, and one end of the cable 510 is connected to the second drive assembly 300, and the other end is connected to the counterweight block 530. Optionally, the cable 510 is connected to the sliding plate 320 of the second drive assembly 300, and one end of the cable 510 connected to the sliding plate 320 and one end of the cable 510 connected to the counterweight block 530 are located on both sides of the beam 130. In other words, the sliding plate 320 and the counterweight block 530 are located on both sides of the beam 130, which is convenient for the setting of the counterweight assembly 500. It should be noted that the number of pulleys in the pulley block 520 is set as needed and is not specifically limited here.

[0047] Further, the counterweight assembly 500 also includes a bearing member 540, which is slidably connected to the frame 100. Specifically, the bearing member 540 is slidably connected to the crossbeam 130 through a guide structure, and the guide structure can be a guide column guide sleeve that cooperates with each other. The pull wire 510 is connected to the bearing member 540, and the counterweight block 530 is placed on the bearing member 540. The bearing member 540 includes a bearing frame, which can accommodate the counterweight block 530. The counterweight block 530 located in the bearing member 540 can be increased or decreased as needed to adjust the gravity of the second drive assembly 300. It should be noted that after the medical screw 002 is installed in the clamp 330, since the medical screw 002 has gravity, it is necessary to adjust the gravity of the counterweight block 530 to balance the common gravity of the medical screw 002 and the second drive assembly 300 to keep the elastic member 400 in a natural state. Since the counterweight block 530 is directly placed in the bearing member 540, it is convenient to take and put. The counterweight block 530 may be a weight, which facilitates direct reading of the weight of the counterweight block 530 and makes operation more convenient.

[0048] In this embodiment, optionally, the testing machine 001 further includes a first sensor 600 and a second sensor 700, wherein the first sensor 600 is used to detect the pressure exerted by the first driving assembly 200 on the medical screw 002 to be tested; and the second sensor 700 is used to detect the torque exerted by the second driving assembly 300 on the medical screw 002 to be tested. Optionally, the first sensor 600 is disposed on the base 110. The second sensor 700 is disposed on the sliding member.

[0049] The test machine 001 provided in this embodiment has a stiffness of the entire system that is approximately equal to the inverse of the stiffness of the elastic member 400. Even when at least one of the medical screw 002 and the simulated bone block 003 is replaced, the stiffness of the entire system changes little, and there is no need to debug the PID value. The measurement is more convenient, the measurement error is small, and the measurement result is more accurate.

[0050] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A testing machine for detecting the self-tapping performance of medical screws, characterized in that: The testing machine comprises: A frame, a first drive assembly, a second drive assembly, an elastic member and a counterweight assembly; the first drive assembly is connected to the frame, the second drive assembly is slidably connected to the frame, the elastic member is located between the first drive assembly and the second drive assembly and can simultaneously abut against the first drive assembly and the second drive assembly; the counterweight assembly is connected to the frame and is used to balance the gravity of the second drive assembly so that the elastic member is in a natural state; the first drive assembly is used to drive the elastic member to move so that the elastic member is compressed and drives the second drive assembly away from the first drive assembly; the second drive assembly is used to drive the medical screw to be tested to rotate; Among them, the stiffness of the first driving assembly is K1, the stiffness of the second driving assembly is K2, the stiffness of the combined structure of the medical screw and the simulated bone block to be tested is K3, the stiffness of the elastic member is K4, K4 is much smaller than the values ​​of K1, K2 and K3, and the stiffness of the testing machine is K0′=1 / (1 / K1+1 / K2+1 / K3+1 / K4), and K0′ is approximately K4.

2. The testing machine according to claim 1, characterized in that: The elastic member includes a spring, and the spring is located between the first driving assembly and the second driving assembly, and two ends of the spring can abut against the first driving assembly and the second driving assembly at the same time.

3. The testing machine according to claim 1 or 2, characterized in that: The elastic member is connected to the first driving assembly and the second driving assembly respectively.

4. The testing machine according to claim 1, characterized in that: The first driving assembly includes a telescopic structure, which is connected to the frame and is used to drive the elastic member to move closer to or away from the second driving assembly.

5. The testing machine according to claim 1, characterized in that: The second driving assembly includes a motor and a sliding member, the sliding member is slidably matched with the frame, the motor is connected to the sliding member, and the motor is used to drive the medical screw to be tested to rotate; the elastic member can be supported on the sliding member.

6. The testing machine according to claim 5, characterized in that: The frame is provided with a guide member, and the sliding member is slidably matched with the guide member.

7. The testing machine according to claim 5, characterized in that: The second driving assembly further comprises a clamp, which is connected to the output shaft of the motor and is used to clamp the medical screw to be tested.

8. The testing machine according to claim 1, characterized in that: The counterweight assembly includes a pull wire, a pulley block and a counterweight block, the pulley block is connected to the frame, the pull wire is wound around the pulley block, one end of the pull wire is connected to the second drive assembly, and the other end of the pull wire is connected to the counterweight block.

9. The testing machine according to claim 8, characterized in that: The counterweight assembly also includes a bearing member, the bearing member is slidably connected to the frame, the pull wire is connected to the bearing member, and the counterweight block is placed on the bearing member.

10. The testing machine according to claim 1, characterized in that: The testing machine also includes a first sensor and a second sensor, wherein the first sensor is used to detect the pressure exerted by the first drive assembly on the medical screw to be tested; and the second sensor is used to detect the torque exerted by the second drive assembly on the medical screw to be tested.

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