Screw is a tool to tighten the parts step by step by using the physical and mathematical principles of circular rotation of the inclined plane and friction force. The function of the screw is mainly to connect the two workpieces together, play the role of fastening, is an indispensable industrial necessity in daily life.
For example, Tiny screws usually used in cameras, glasses, clocks, electronics, etc.;General screws used in television, electrical products, musical Instruments, furniture, etc.; Large screws and nuts are used in engineering, construction and Bridges; and both Large screws and tiny screws combined together for transportation equipment, aircraft, trams, cars, etc. The screw plays an important role in industry. In terms of application field, it is the first human invention.
While In fact, screw is a general term, and screws can be divided into varieties of cagegories based on different characteristic. Screws, which is a kind with sharp head at the front end and large pitch,will be called wood screws. It is generally used for fastening wooden parts and plastic parts. The screw which is a kind of front flat head, the pitch is small and even, will be called machine screw,it is generally used for fastening metal, machine parts.
According to the unit of measurement, screw can be divided into metric standard, American standard, and British standard.
According to the head shape,screw can be divided into hexagon head,hexagon head with flange,square head,T head (hammer head),mushroom head(truss head),cheese head,round head,pan head, countersunk head (flat head),raised countersunk head.
According to the groove type, it can be divided into inline shape, inner triangle, inner corner square, cross, pozidriv type, flower shape, plum shape, plum blossom zigzag , special shape, inner hexagon.
According to the purpose, screws can be divided into machine screws, setting screws and special purpose screws.
Post time: Dec-28-2022