What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In the prior art, there are two ways to feed the screws of the locking screw machine, the air blowing type and the air suction type. The air suction type is suitable for relatively small screws. If the screw size is larger than M2, smaller than M5, and the length-diameter ratio is larger than 1.7, the air-blown screw machine can be selected.
1. The taper of the reaming hole should be 90°. It should be guaranteed that it should be less than 90° rather than greater than 90°. This is a key trick. 2. If the thickness of the sheet metal is less than the thickness of the head of the countersunk head screw, you can replace the screw with a smaller size, or it is better to ream a smaller hole instead of reaming the hole to increase the diameter of the bottom hole and cause the parts to not be pressed tightly. 3. If there are multiple countersunk head screw holes on the part, it should be processed more accurately. Once it is drilled crookedly, it will be ugly to assemble, but as long as the error is not large, it can be tightened completely, because when tightening, if the diameter of the screw is not very large. Large (about no more than 8mm), when there is an error in the hole distance, the screw head will be deformed due to the force when it is tightened or it will be tightened.
If the above-mentioned nuts and screws are used as a kind of fasteners that can prevent others from being disassembled, such as when installing iron doors-steel windows, people usually tighten the nuts first, and then use a welding machine to weld the nuts and screws. To prevent the nut from loosening, it may be necessary to use a tool to mill the threads on the screw. It can be seen that this approach is very inconvenient.
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.
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