A novel weft insertion mechanism named eccentric conjugate non-circular gear & crank-rocker & gears train weft insertion mechanism was proposed in order to better meet the requirements of rapier loom's weft insertion mechanism as well as reduce the manufacturing difficulty. Meanwhile, based on the working principle of this mechanism, kinematical mathematic models of this mechanism were established and an aided analysis and simulation software was compiled. The influences of eccentricity ratio, deformation coefficient, and other important parameters on the kinematics characteristics of this mechanism were analyzed by using the software. A group of preferable parameters which could meet the requirements of weft insertion technology were obtained by means of human-computer interactive optimization method. The maximum velocity, maximum acceleration, and variation of acceleration of this mechanism are smaller than those of the conjugate cam weft insertion mechanism applied on TT96 rapier loom under the conditions of the same unilateral total stroke of rapier head and the same rotary speed of loom spindle; meanwhile the other demands of weaving technology can be met by this novel weft insertion mechanism.
In order to analyze the kinematic performances of elliptic-gear and crank-rocker(EGCR) beating-up mechanism, kinematic mathematic models of the mechanism were established, and an aided analysis and simulation software were compiled. This software can display the kinematic characteristics and simulation motion of the mechanism according to different parameters. It also supplies a platform for human-computer interaction. A group of satisfactory parameters were selected by the software. A test bed of EGCR beating-up mechanism was developed according to these parameters. The kinematic performances of the mechanism were verified by high-speed video tape recorder.
In order to realize the parametric design of the conjugate cam weft insertion mechanism,according to the necessary parameters of weft insertion process,ideal kinematic curves of the weft insertion mechanism were given,and the mathematical model of reverse solution for this mechanism was established.The parameters of this mechanism were obtained by reverse solution on the basis of the given ideal kinematic curves and kinematic requirements.The parametric design platform which was integrated with the functions of parametric reverse solution,motion simulation,three-dimensional modeling and virtual assembly was developed based on VB.NET and Unigraphics(UG) NX.After entering the technological parameters of weft insertion process and essential structural parameters by users,three-dimensional drawing of the main parts such as the conjugate cam and shaft,can be obtained by this platform,also the processing data of the cam can be calculated.This platform provides a rapid approach for parametric design of weft insertion mechanism.
For the purpose of obtaining satisfactory performance of the non-circular gear & crank-rocker & gear trains (NCCRG) weft insertion mechanism which was proposed in this paper, the ideal kinematic curve of this weft insertion mechanism was given, and the reverse solution models of this mechanism were established. A reverse design and simulation software was compiled based on Visual Basic 6.0 to obtain the mechanism parameters, including the pitch curves and tooth profiles of the non-circular gears. A test-bed of this mechanism was developed according to these parameters. The kinematic performance of this weft insertion mechanism was tested by high-speed video tape recorder with its corresponding video analytical software Blaster's MAS. And the test results were identical with the theoretical calculation. Compared with the conjugate cam weft insertion mechanism which is applied on TT96 rapier loom, under the condition of same weft insertion rate, the variation of acceleration of this mechanism is smaller. This novel weft insertion mechanism can meet the requirements of weft insertion on rapier looms with smooth and steady motion.
In order to analyze the kinematic performances of elliptic-gear & eccentric slider-crank & uniform-pitch screw weft-insertion mechanism proposed by us,kinematic mathematic models of the mechanism were established,and an aided analytic software was compiled.Influences of some important parameters on the kinematic characteristics of the mechanism were analyzed.A group of preferable parameters were obtained according to the software and some requirements.Comparisons of kinematic performances were made between the proposed mechanism and the variable-pitch screw insertion mechanism of C401 rapier loom manufactured by Vamatex Corp in Italy.The results show that the proposed mechanism can meet the requirements of inserting wefts.
