Selection of screw and pin of inspection tool

Generally, the fixed installation of parts requires two pins and two nails. In special cases, it is two pins and one nail. The design is mainly to determine their specifications and fixed position. Pin is mainly used for positioning between parts in machinery. The types of pin include cylindrical pin, conical pin, pin with hole, etc. the basic forms of pin are cylindrical pin and conical pin. The pin hole can be cut or reamed by wire. The cylindrical pin is fixed in the pin hole by micro interference. Repeated assembly and disassembly will reduce the positioning accuracy. The conical pin has a taper of 1:50, which can be self-locking and fixed in the pin hole by the extrusion of the conical surface, The positioning accuracy is high, the installation is convenient, and the assembly and disassembly can be repeated. During the design, attention should be paid to the effective positioning of the pin, the convenience of disassembly and assembly, and the reasonable stress. Attention should also be paid not to seriously weaken the strength of the parts due to the pin holes on the parts, resulting in fracture failure. Screw connection is widely used in mechanical design. Screw connection is reliable, easy to disassemble, highly standardized, and has multiple structural forms, which can meet various work needs. There are many kinds of screws and pins, which should be selected according to the actual needs. It is better to use the hexagon screw, which is reliable, the screw does not leak out, and the appearance of the inspection tool is beautiful. Screw, pin specifications should be based on the size of the inspection tool and stamping process force, flange thickness, etc. Screw specifications can be determined by referring to the table, pin commonly used cylindrical, the same combination is generally not less than two.