What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The self-tapping locking screw is composed of three parts: the head, the stem and the end of the stem from beginning to end. The composition of each self-tapping screw has four major elements: head shape, wrenching method, thread type, and end type. Head Shapes - Head shapes come in all shapes and sizes. There are round head (semi-round head), oblate head, round head flange (with pad), oblate head flange (with pad), pan head, pan head flange (with pad), countersunk head, semi-countersunk head, Cylinder head, spherical cylinder head, horn head, hexagonal head, hexagonal flange head, hexagonal flange (with gasket), etc. Wrench Styles - There are various ways of wrenching. External wrench: hexagonal, hexagonal flange, hexagonal flange, hexagonal flower shape, etc.; internal wrench: slotted, cross groove H type (Phillips), cross groove Z type (Pozidriv), cross groove F type (Frearson) , Square groove (Scrulox), compound groove, internal spline, internal hexagon flower (plum groove), internal triangle, internal hexagon, internal 12-angle, clutch groove, six-blade groove, high torque cross groove and so on. Thread Types - There are many types of threads. There are self-tapping threads (wide thread), machine threads, drywall screw threads, fiberboard screw threads, and some other special threads. In addition, the thread can be divided into single lead (single head), double lead (double head), multi-lead (multiple head) and high and low thread double head thread. End type - The end type mainly includes saw end and flat end. However, according to the function of use, grooves, grooves, incisions or parts with a cutting function can be processed. In some standards, the same saw end or flat end, there are different forms. There are various changes in the head shape, wrenching method, thread type and shank end type of self-tapping screws. They can be combined with each other to show many different products belonging to the category of self-tapping screws.
A rivet is a part that uses its own deformation or interference to connect the riveted parts in riveting. With the continuous progress and development of science, rivets have been used in many occasions because of their convenient use and reliable connection. The rivet includes a nail head and a stem. The traditional processing mold for the rivet head includes a base, and a nail head forming part is arranged on the base. However, due to the limited service life of the mold, the processing mold of this structure is replaced. It needs to be replaced together with the base, which is a waste of material, which increases the production cost, and the rivet itself is relatively cheap, so this reduces the profit of the enterprise.
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.
In the prior art, the spring washer has a certain anti-loosening effect. However, due to the unreasonable design structure, the upper and lower pressing forces of the spring washer and the spring washer's anti-return force are poorly matched, resulting in the smooth surface and the bolt head. The friction between the nut and the connected parts is small. When the bolt or nut is subjected to strong vibration, the bolt or nut will still loosen. Therefore, the anti-loosening effect of the above spring washer still needs to be improved.
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