Design And Application Of Plane Connecting Rod Stopping Mechanism

The method of atlas,graphic or optimization design is usually used in the dimensional synthesis of planar linkage mechanism.The accuracy of the atlas method is low,the efficiency of graphic method is relatively low,the optimization method and the algorithm principle are complex.In order to solve these problems,a more efficient and accurate mechanism dimensional synthesis method for Watt II six-bar linkage dwell mechanism is explored and applied to the design of loop motion device of the less comb warp knitting machine.The types of six-bar linkage kinematic chains were analyzed,as well as corresponding to different types of mechanism,Watt II can achieve a dwell,Watt II six-bar dwell mechanism is generally II level mechanism and its structure is simplest.The dwell principle of Watt II six-bar linkage is analyzed.It can be classified as four kinds of dead point(limits)positions,that is outer-outer,outer-inner,inner-outer and inner-inner dead points,when the active connecting linkage and corresponding connecting linkage of first,second level four-bar linkage in the vicinity of collinear or overlapping position,the approximate dwell of the mechanism follower connecting linkage realized.Dimensional synthesized of the Watt II six-bar dwell mechanism with graphic method,in the case of four kinds of dead points,there are two preset conditions in each case,namely the position and length of follower connecting linkage or moving output lingkage of second level four-bar linkage mechanism were preseted,the size of the active crank dwell angle,the swing angle range of the follower output linkage and the geometric relation of the limit position were used,and the position and length of the moving input lingkage or follower connecting linkage of the second level four-bar linkage mechanism were solved.On the basis of graphic method,related quantitative relation expressions of Watt II six-bar dwell mechanism were directly derived through the use of analytical method,according to the two preset conditions,two results were obtained:the included angle between the moving output linkage of first level four-bar linkage and moving input linkage of second level four-bar linkage,the length of moving input linkage and connecting linkage of second level four-bar linkage,the length of connecting linkage and the follower connecting linkage of second level four-bar linkage.The analytic method is applied to the dimensional synthesis of the loop forming mechanism of RS6EL less comb warp knitting machine.The loop knitting process is analyzed,the movement requires obtained:groove pin and closing element had upper and lower linear motion with a dwell,dwell time were107~°and120~°and moving range were 14 and 8mm respectively,sinker and guide bar had reciprocating swing with a dwell,dwell time were109~°and37~°and moving range were 4.5 and 19mm respectively.The structure of the moving mechanism was selected,and the groove pin was six-bar linkage,and closing element,the sinker and the guide bar were all eight-bar linkages.The mechanism scale was comprehensived and motion analyzed,the dwell time of groove pin,closing element,sinker and guide bar movement mechanism were1066.~°?1195.~°?1094.~°and374.~°,compared with the demand,the relative error were 0.56%,0.42%,0.55%and 1.1%respectively,moving range were14.4,8.3,4.6 and 19.5mm,compared with the demand,the relative error were 2.9%,3.75%,2.2%and 2.6% respectively.