out of phase with each other consequently the cam levers 18 pivot about the shaft 12 under the action of the cam plates 16 and 17 rotating synchronously in the direction of an arrow 55 as shown in fig3 and the cam rollers 45 and 46 move between their solid line positions and double dot chain line positions 45a 46a so that the jack lever 4 integral with the cam levers 18 also moves between its solid line position and double dot chain line position 4a thus causing the heald frame to perform a vertical motion more specifically when the heald frame is to be brought down the jack lever 4 pivots up to its double dot chain line 4a position under the action of a large diameter portion 16a of the cam plate 16 while when the heald frame is to be brought up the jack lever 4 pibots from its double dot chain line position 4a to its solid line position 4 under the action of a large diameter portion 17a of the cam plate 17 on the cam roller 46 thus the heald frame is moved in both up and down directions positively using cams the following description is now.