What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
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.
Gaskets are divided into: flat washer - grade C, large washer - grade A and C, extra large washer - grade C, small washer - grade A, flat washer - grade A, flat washer - chamfer type - Grade A, high-strength washers for steel structure, spherical washers, cone washers, square bevel washers for I-beam, square bevel washers for channel steel, standard spring washers, light spring washers, heavy spring washers, internal tooth lock washers , Internal serrated lock washers, external serrated lock washers, external serrated lock washers, single-ear stop washers, double-ear stop washers, outer tongue stop washers and stop washers for round nuts, etc.
The nuts in the prior art are easy to fall off during work, especially in harsh environments or environments with large vibrations. Sometimes it is necessary to add parts such as gaskets to prevent them from falling off, but they are still easy to fall off and cause harm.
Round head three-combination screw The screw size in the round-head three-combination screw is GB818, and the main technical requirements of various types are: iron and stainless steel material requirements, iron low, medium, high carbon steel, stainless steel combination The materials of the screws are stainless steel 201, stainless steel 304 and stainless steel 316. The thread tolerance is 6G, and the mechanical properties of the iron combination screws are 4.8 and 8.8. The 4.8-level combination screws are ordinary steel, and the maximum allowable hardness is 255HV. The 8.8-level combination screws are generally made of wire rod 10B21. , and then undergo hardening treatment, and then dehydrogenation after hardening treatment. Hydrogen removal is to prevent hydrogen embrittlement of the spring washer in the combination screw. Prevent the spring pad from breaking. The tolerance class of the combination screws is A. The cross groove is H-shaped. The surface treatment of the combination screw has environmental protection and non-environmental protection. Such as, environmental protection blue zinc, environmental protection color zinc, black zinc, color zinc, white nickel and so on. The technical requirement of the combination screw for the spring washer is that the washer should be able to rotate automatically without falling off.
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