Abstract: According to the movement requirements of upper hooks during the net-forming process of a fishing net machine, different types of mechanisms with different structures respectively for implementing oscillation and rotation movements of upper hooks are chosen. Practically they are a planar linkage-cam ncombined mechanism and a cylindrical cam-linkage-gear rack combined mechanism. The movement requirements are primarily disposed during the dimensional synthesis, so that the acceleration curves of the movement requirements can continue. Furthermore the dimensional synthesis is studied by employing the analytical method. To obtain the data of cam contours and curves of both mechanisms, an example is given to illustrate the process of the specific design.

Key words: upper hooks; fishing net machine; knitting; knot; combined mechanism