Research on tightening and receding of wefts

For tightening and receding of wefts,the conditions under which wefts recede from the back beam and move forward towards the front beam relative to warps are developed by combining equilibrium condition of forces of warp with critical slip condition of weft.On this basis,the range of weft density on loom within which receding or moving forward of wefts will not occur is determined,and the method to calculate the number of receded wefts and their front-side warp angles at receded position are given.The mechanism that the newly woven-in weft drives the receded weft to be beaten tight again during beating-up is analyzed.The process calculating back-side warp angles of receded wefts at tightened position is presented,and then a formula of displacement that receded weft slips from receded position to tightened position is given.A curve diagram of front-side warp angles of receded wefts relative to frictional coefficient between warp and weft is drawn,and application of the diagram is illustrated.