There is a distinction between general mechanical equipment as well as specialized equipment. They are not according to the use of life to distinguish, but according to the scale of use (industry) to distinguish. Generally speaking: the use of more than one industry equipment can be categorized in the general equipment, such as machine tools, motors, air compressors, crankshafts, cooling equipment, water supply equipment and so on. Can only be used in one industry class equipment is generally categorized in the special equipment, such as clock equipment, injection molding equipment, mining, agricultural machinery, chemical industry and so on. General-purpose equipment may also have two different kinds of distinction, such as machine tools have ordinary (general) machine tools and special machine tools for special purposes General parts: a national or international standards for the benchmark and the production of parts known as general-purpose parts, can be broadly divided into the following categories: transmission: gear transmission, chain drive, belt drive, worm drive, screw drive; shaft: couplings, clutches, Rolling bearings, plain bearings; connection class: bolts, keys, splines, pins; other: springs, racks, boxes ...... special parts, special parts: a part of their own machine standards and production, in the national and international standards have no counterpart in the product of the parts known as special parts, for example, a factory for a piece of equipment and the production of special parts. Some parts.