Double Back Rests System Design And The Control Of Warp Tension On An Air-jet Loom

Air-jet loom is one of the most promising looms. In weaving process, warp tension is an important parameter in looms,therefor the control of warp tension is a key technology.Thus the back rest system of a loom plays an important role in control of warp tension.Up to now,research on dynamic analysis of back rest system of air-jet looms is seldom reported in home and abroad,naturally research about double back rests is rarely deal with.So the research on double back rests system is of great significance.This dissertation uses WG-2000 single back rest system of air-jet loom as the object,analyzes the influence on warp tension by weaving movements,sets up the static and dynamic models ,and obtains the influence on warp tension and the activities back rest swing by the change of the diametre of beam.Based on the single back rest system,a double back rests system designed by adding a fixed back rest to reduce the affection of the change of beam's diametre is analysed.According to the designed doule back rests system,a three DOF dynamic model is established by considersing the rotation of the fixed back rest and the swing and rotation of activities back rest.Conclusions have been made that the rotation of the fixed back rest and the activities back rest's swing are biggger than the rotation of the activities back rest, while the warp tension fluctuation smoothly. Thought analysis the fixed back rest's position on the weaving process , concluded that change of fixed back rest's position is on the less impact each parameter on weaving process. The research find that the smaller stiffness of the spring the better to reduce the warp tension fluctuation.Based on analysis,the easing device can be removed in oder to save the cost for it does not have significant effect to loose the warp tension in the double back rests system.Compared with the single back rest system,the designed double back rests system has more advantages for its simpler structure and the activities back rest's swing is smooth .The warp tesion sensor's sensitivity can be insured to control the warp tension better. The conclusions have some signinficance on improving the structure of looms.