In the modern industry mainly include mechanical drive, hydraulic drive, pneumatic drive and electrical drive, including mechanical driving is a basic mode of transmission, zui it meshing transmission and friction drive to transfer force and motion, triangle just reflects the important role in it. Tightness is usually to determine, based on the experience of using, it is good to adjust the belt when driving to skid. No theoretical calculation basis. Belt has several kinds, also has a lot of specifications, the belt length to the hands of tightness of normal transmission pressure central belt, also depends on the length of the belt, leather belt, the longer the greater the degree of pressure. According to the experience, you use the more popular is rural tightness of diesel engine drives the machine work is: to pressure in tight triangle side span is about 20 n ( About 2 kg) The force, triangle subsidence 8 - It is advisable to 12 mm. The triangle model, when using the correct inspection method is: in the middle of each tape with the hand, the sink of the 2 kg of vertical pressure, to ( 20 - - 30) Millimeter advisable, is improper to adjust in a timely manner.