Hunan Zhongding machinery specializing in the production of wholesale mobile scissor lift, scissor lift is determined by the structural characteristics of each supporting rod between the need has been reached in the hydraulic actuator driven by the hoisting and falling action connected by bolts. It is necessary to analyze and sum up the selection of bolt type and bolt fastening method.
Type selection of scissor type elevator bolt
Ordinary bolt connections such as GB/T5782-2000 type bolt is mainly through bolts to two contact surface tightly, rely on the friction contact surface of the arrival of the fastening effect, the radial force of bolt axial force and generally smaller. The reason for not being able to bear the radial force is that when the bolt is subjected to pure shear (Jing Xiangli), the stress concentration will result in bolt fatigue or bolt shearing. The analysis of the shear fork support rod bolt connection bolt must be able to withstand the large shear force, so the GB/T5782-2000 type bolt is not suitable for fork lift support link. In the process of bolt design, we should learn from the GB/T27-1988 six head hinge hole bolt form. At this time should be strictly controlled according to the national standard of the rod sleeve and bolt between the light rod, has achieved the desired results
Scissor type lifting bolt fastening method
The fastening bolts shall be thoroughly cleaned before, bolts, bolts and nuts to remove surface dirt, grease, iron and other foreign bodies, in order to improve the surface quality of bolts and nuts, reduce the friction coefficient increase screw bolt tightening torque. Due to the large weight of the shear fork lift, the shear force of the bolt is increased accordingly, which results in larger bolt diameter. Under normal circumstances, when the bolt diameter is greater than M36 in the bolt after the cleaning, the need to be sprayed on the surface of the bolt or similar equivalent to reduce the friction of the thread
Bolt process if improper operation is caused by the uneven loading of the bolt, reduce the service life of bolt, to reflect the scissor lift system, may cause serious uneven scissor lift its tilt fork lift force cut somewhere. Based on the above, the process of bolt tightening process is crucial to the performance and service life of fork lift. According to our experience fork lift bolt tightening process is as follows:
1, bolt with a tight manual
2, set the hydraulic wrench tightening torque, the bolt for 50% moment bolt tightening
3, in the process of bolt should follow the principle of bolt cross symmetric pre tightening
4, the bolt for 100% moment bolt tightening
5, the bolt tightening torque is full, you need to use the same torque wrench to check the bolt in the fork lift system, bolt is one of the most important components. Reasonable selection and fastening bolts, for fork lift stability will be improved.