What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Pedicle screws can be divided into four types: one-way short-tail screw, one-way long-tail screw, universal short-tail screw and universal long-tail screw. Pedicle screws can effectively complete the three-column fixation of the spine and are clinical The most widely used internal fixation method for the treatment of spine-related diseases. Due to the different types of pedicle screws, four different screwdrivers are required to complete the screw insertion. However, the implantation of pedicle screws is performed in a complex three-dimensional space, which has high difficulty and risk. Mis-implantation of screws may cause instability of the internal fixation frame in the early stage, and may cause false joint formation in the later stage. Therefore, in the process of spinal internal fixation, it is necessary to ensure the accurate implantation of pedicle screws is the key to the success of the entire spinal internal fixation, and the selected implanted instruments are particularly important.
Yueluo also provides a thin plate rivet structure, which includes a metal thin plate and a rivet. The metal sheet is provided with a riveting hole; the riveting piece is penetrated in the riveting hole, the outer edge of the riveting piece is provided with an occlusal structure, and the inner edge of the riveting hole is embedded with the occlusal structure. A deformation groove is provided on the metal sheet, and the deformation groove is adjacent to the rivet hole.
The anti-theft screw of this structure has two disadvantages. One is that the polygonal block moves up and down in the polygonal hole, and the polygonal hole in the connecting piece and the polygonal hole on the threaded part have no limit structure. Because of the polygonal structure, the two If the polygonal holes of the parts cannot be aligned, dislocation occurs, and any edge may block the up and down movement of the polygonal block, which is very unsmooth during use. The second is that the shell of the lock cylinder and the hexagonal part are connected by pins, and the pins are exposed on the hexagonal parts, which are easily damaged and leave opportunities for theft; once the pin is pried off, the lock cylinder will be taken out, and the entire anti-theft screw will be lost. and the pin fixation is sometimes unstable, which is detrimental to theft.
T-bolts are often used in conjunction with flange nuts, which are standard supporting connectors when installing corner fittings, and can be automatically positioned and locked during the installation process. At present, in the welding process of T-bolts, there is often a method of manual welding. Using such a method, the manufacturing cycle is long, the labor intensity is high, the production efficiency is low, and the welding quality is difficult to guarantee.
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