What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Referring to Figure 1, one end of the existing insert nut 1' is embedded in the injection molded part 2', and the other end is exposed to the injection molded part 2'. The insert nut 1' has opposite lower and upper end surfaces in the axial direction. The end face of one end of the insert injection molded part 2' is the lower end face. In order to reduce the resistance during hot pressing, the connection between the inner wall surface and the lower end surface of the insert nut 1 ′ is provided with an inclined surface. However, when the embedded nut 1' of this structure is hot-pressed, the hot melted glue will generate a shunt that rises along the slope, and then a convex peak is formed in the screw hole of the embedded nut 1', and the convex peak occupies the screw. The space in the hole prevents the screw 5' from being completely screwed in; at the same time, due to the shunting of the hot solder, the knurling of the inner nut 1' near the upper end face cannot be filled with the solder, which makes the inner nut 1' and the inner nut 1' and The injection part 2' is not firmly embedded. Therefore, the locking strength of the existing insert nut 1 ′ and the screw 5 ′ after being hot-pressed is relatively low.
There are two typical pin shearing fixture tooling, among which the traditional fixture shown in Fig. 1 is more complicated and consists of fixture, spacer, washer and shearing block guide post, hardened bushing, shearing block and so on. The cylindrical pin is installed in the hardened bushing, and the axial load is applied through the shear block to complete the shear test. The fixture is complicated in manufacture and has many consumables, because the size of the hardened bushing is similar to that of the cylindrical pin. , and to keep the notch of the cylindrical pin upward, it is difficult to install before the test, and the broken cylindrical pin after the test remains in the hardened bushing and is difficult to remove.
The technical problem to be solved by Yueluo is to provide a medical self-locking screw, which can fix the inner screw inside the outer screw, expand the outer screw head through the thimble on the inner screw, and use the outer cone on the inner screw. The body expands, compresses the surrounding bone, and achieves a double locking effect through the self-locking between the internal and external screws; it can hook the surrounding fixed parts when the anti-retraction ring is retracted to achieve the anti-regression effect; effectively prevent false implantation. After a long period of service, the looseness, fretting and other adverse reactions of the body are used to solve the defects caused by the existing technology.
In order to solve the above technical problems, Yueluo provides a screw installation method. When using this method to install screws, the sensor must sense that the screws have been adjusted to the specified position before allowing the screws to be energized, which prevents the screws from being adjusted. Accidents of personal injury caused by operating errors during the process. The technical solution adopted by Yueluo to solve its technical problems is a screw installation method, which includes the following steps: a. Fix the screw hole structure that needs to be installed on the workbench, and fix the corresponding size screw to the screw mouth; b. Adjust the sensor on the track groove to the vertical position just above the screw hole structure; c. Adjust the screw position until the sensor on the screw senses the signal sent by the sensor; d. Turn on the screw power supply, and install the screw into the screw Inside the hole structure, the installation is complete. Compared with the prior art, Yueluo has the following beneficial effects. The screw installation method provided by Yueluo has the steps of preventing accidental hitting, which avoids personal injury accidents caused by operation errors during the screw adjustment process.
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