Vertebral resection fatigue test device

Abstract

The present invention discloses a vertebral resection fatigue test device, comprising an upper connecting member and a lower connecting member of the same structure. A threaded column that can be threadedly connected to a testing machine is provided on the web of a U-shaped frame and can rotate relative to the overall structure composed of a supporting cylinder and a base. The threaded column and the U-shaped frame can only transmit bending moment but not torque. Circular through holes are respectively opened along the same axis on the left and right wing plates of the U-shaped frame. The U-shaped frame is connected to the U-shaped frame through a load-bearing roller shaft that passes through each ultra-high molecular weight polyethylene block and the two circular through holes. The threaded end of the load-bearing roller shaft is fixed to the U-shaped frame through a roller shaft fixing nut. The use of roller shafts to carry samples effectively improves the force uniformity of the test samples, avoids test errors caused by stress concentration or unnecessary torque, and enables the ultra-high molecular weight polyethylene blocks to slide along the roller shaft, thereby facilitating the elimination of stress caused by different installation positions.

Description

Technical Field

[0001] The present invention relates to a fatigue testing device, in particular to a vertebral body resection fatigue testing device. Background Art

[0002] Vertebral resection is a common treatment method for spinal diseases such as congenital scoliosis or thoracic and lumbar fractures. Vertebral resection fatigue test is an important performance indicator for evaluating the reliability of spinal implants, which directly determines the reliability of spinal implants in long-term use in the human body. In the fatigue test of spinal implants, the spinal implants, such as Figure 1 The upper and lower ultra-high molecular weight polyethylene (UHMWPE) blocks 1 are connected by two spinal rods 7, the upper and lower ends of which are secured to the upper and lower UHMWPE blocks 1 by spinal screws 6. The spinal screws 6, spinal rods 7, and UHMWPE blocks 1 are all test specimens specified in YY / T 0857-2011. To ensure that the two spinal rods are pointing vertically downward, the experimental apparatus must apply a cyclically varying test load to the assembly of the spinal screws 6, spinal rods 7, and UHMWPE blocks 1. This load must be applied to the assembly, securing the spinal implant while transferring the load to the center of the UHMWPE blocks and meeting the specimen installation requirements of YY / T 0857-2011. In the existing test apparatus, the specimen position is difficult to adjust, making it impossible to ensure that the spinal implant is parallel to the load direction. This results in uneven force on the test specimen and unsatisfactory experimental results. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a device that can achieve the overall fixation of spinal implants and ultra-high molecular weight polyethylene and apply fatigue loads, which can be rigidly connected to the testing machine to transfer loads and has a certain degree of test sample position adjustment capability.

[0004] The vertebral resection fatigue test device of the present invention comprises an upper connecting member and a lower connecting member of the same structure, wherein the upper connecting member and the lower connecting member both comprise a U-shaped frame, a cylindrical head of a threaded column with a cylindrical head is sleeved in the bottom groove of the base, a light hole is opened in the middle of the top wall of the bottom groove, a threaded rod section of the threaded column is arranged through the light hole, a nut is threadedly connected to the upper part of the threaded rod section, the bottom wall of the nut is clearance-matched with the top wall of the base, the bottom wall of the base is fixed to the top wall of the supporting cylinder, and the supporting cylinder is provided with a screw thread. The bottom wall is fixed to the top wall of the web of the U-shaped frame, and the threaded column can rotate relative to the overall structure composed of the supporting cylinder and the base. Circular through holes are respectively opened on the left and right wing plates of the U-shaped frame along the same axis. The upper and lower ultra-high molecular weight polyethylene blocks are respectively arranged in the grooves of the U-shaped frame of the upper connecting piece and the lower connecting piece, and are connected to the U-shaped frame through load-bearing rollers passing through each ultra-high molecular weight polyethylene block and the two circular through holes. The threaded ends of the load-bearing rollers are fixed to the U-shaped frame through roller locking nuts.

[0005] Advantages of the present invention:

[0006] 1. Threaded connection testing machine, easy to install and can directly transmit load.

[0007] 2. Use rollers to carry the sample and transfer the load, ensuring that the spinal implant is parallel to the load direction.

[0008] 3. The sample is loaded on a roller and the position of the sample can be adjusted horizontally.

[0009] 4. The use of rollers to load the sample effectively improves the force uniformity of the test sample, avoids test errors caused by stress concentration or unnecessary torque, and enables the ultra-high molecular weight polyethylene block to slide along the roller, which is convenient for eliminating stress caused by different installation positions.

[0010] 5. The support cylinder and the base can rotate relative to each other, so that only bending moment but not torque can be transmitted between them. And the upper and lower symmetrical device is used to automatically adjust the entire specimen to be parallel to the direction of the force when the preload is applied.

[0011] 6. The roller and roller nut make loading samples more convenient and can also effectively prevent samples from falling out.

[0012] 7. Able to meet the requirements of YY / T 0857-2011 for fatigue testing of spinal implants. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a three-dimensional diagram of the overall structure of the vertebral resection fatigue test device;

[0014] Figure 2A three-dimensional diagram of the frame body of the vertebral body resection fatigue test device;

[0015] Figure 3 A three-dimensional view of the tooling lock nut of the vertebral body resection fatigue test device;

[0016] Figure 4 A three-dimensional diagram of the load-bearing roller of the vertebral resection fatigue test device;

[0017] Figure 5 A three-dimensional view of the roller shaft locking nut of the vertebral body resection fatigue test device;

[0018] Figure 6 This is a schematic diagram of the bottom of the base of the vertebral body resection fatigue test device;

[0019] Figure 7 Schematic diagram of the overall structure of the threaded column of the vertebral resection fatigue test device. DETAILED DESCRIPTION

[0020] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] As shown in the accompanying drawings, the vertebral resection fatigue testing device of the present invention includes upper and lower connecting members of identical structure. Each of the upper and lower connecting members includes a U-shaped frame 4. A threaded column 10 with a cylindrical head is inserted into the bottom groove of the base 8. A light hole is formed in the middle of the top wall of the bottom groove. The threaded rod section of the threaded column 10 is inserted through the light hole. A nut is threadedly connected to the upper portion of the threaded rod section. The bottom wall of the nut is loosely matched with the top wall of the base 8. The bottom wall of the base 8 is fixed to the top wall of the support cylinder 9, which is fixed to the top wall of the web of the U-shaped frame 4. The threaded column 10 can rotate relative to the integral structure consisting of the support cylinder 9 and the base 8, so that only bending moment, but not torque, can be transmitted between the threaded column 10 and the U-shaped frame 4. During the test, the threaded column is threadedly connected to the testing machine.

[0022] Circular through holes are respectively opened on the left and right wing plates of the U-shaped frame 4 along the same axis. The upper and lower ultra-high molecular weight polyethylene blocks 1 are respectively arranged in the grooves of the U-shaped frame 4 of the upper connecting part and the lower connecting part, and are connected to the U-shaped frame 4 through the load-bearing roller shaft 2 passing through each ultra-high molecular weight polyethylene block 1 and the two circular through holes. The threaded end of the load-bearing roller shaft is fixed to the U-shaped frame 4 through the roller shaft locking nut 3.

[0023] When in use, after passing the load-bearing roller 2 through the circular hole of the ultra-high molecular weight polyethylene block 1 and the circular through hole of the U-shaped frame 4, the U-shaped frame 4 is locked with the roller locking nut 3 to ensure that the sample will not fall out and facilitate the application of load to the sample.

[0024] The method of using this device is:

[0025] (1) The U-shaped frames 4 of the upper and lower connecting parts of the device are connected to the threaded holes of the upper and lower working surfaces of the testing machine through threaded columns, and the tooling as a whole is locked and fixed to the upper and lower working bases of the testing machine through locking nuts 5.

[0026] (2) Connect the load-bearing roller 2 through the ultra-high molecular weight polyethylene block 1 and the two circular through holes to the U-shaped frame 4, and use the roller fixing nut 3 to lock the frame body.

[0027] (3) Use the same method to connect the U-shaped frame 4 of the lower connecting piece to the testing machine and the ultra-high molecular weight polyethylene block 1.

[0028] (4) The vertebral resection fatigue test device was subjected to the method in YY / T 0857-2011, and a preload was applied to the entire device to start the vertebral resection fatigue test.

[0029] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Vertebral resection fatigue test device, characterized by: The invention comprises an upper connecting member and a lower connecting member of the same structure, wherein the upper connecting member and the lower connecting member both comprise a U-shaped frame, a cylindrical head of a threaded column with a cylindrical head, which is fitted into the bottom groove of the base, a light hole is opened in the middle of the top wall of the bottom groove, a threaded rod section of the threaded column is arranged through the light hole, a nut is threadedly connected to the upper part of the threaded rod section, the bottom wall of the nut is clearance-matched with the top wall of the base, the bottom wall of the base is fixed to the top wall of the supporting cylinder, the bottom wall of the supporting cylinder is fixed to the top wall of the web of the U-shaped frame, the threaded column can rotate relative to the integral structure consisting of the supporting cylinder and the base, circular through holes are respectively opened along the same axis on the left and right wing plates of the U-shaped frame, the upper and lower ultra-high molecular weight polyethylene blocks are respectively arranged in the grooves of the U-shaped frames of the upper connecting member and the lower connecting member, and are respectively connected to the U-shaped frame by a load-bearing roller shaft passing through each ultra-high molecular weight polyethylene block and the two circular through holes, and the threaded end of the load-bearing roller shaft is fixed to the U-shaped frame by a roller shaft locking nut.

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