Figs. 129, 130. Stop and rotary motions
[Fig. 131]. The two crank-shafts are parallel in direction, but not in line with each other. The revolution of either will communicate motion to the other with a varying velocity, for the wrist of one crank working in the slot of the other is continually changing its distance from the shaft of the latter.
Figs. 131, 132, 133. Irregular Motions
Figs. [132] and [133]. These are parts of the same movement, which has been used for giving the roller motion in wool-combing machines. The roller to which the wheel F, ([Fig. 132]) is secured, is required to make 1⁄3 revolution backward, then 2⁄3 revolution forward, when it must stop until another length of combed fibre is ready for delivery. This is accomplished by the grooved heart-cam C, D, B, e, ([Fig. 133]) the stud working in the said groove; from C to D it moves the roller backward, and from D to e it moves it forward, the motion being transmitted through the catch G, to the notch wheel F, on the roller-shaft H. When the stud A arrives at the point e in the cam, a projection at the back of the wheel, which carries the cam, strikes the projecting piece on the catch G, and raises it out of the notch in the wheel F, so that while the stud is travelling in the cam from e to C, the catch is passing over the plain surface between the two notches in the wheel F, without imparting any motion; but when stud A arrives at the part C, the catch has dropped in another notch and is again ready to move wheel F and roller as required.
[Fig. 134]. An arrangement for obtaining variable circular motion. The sectors are arranged on different planes, and the relative velocity changes according to the respective diameters of the sectors.
[Fig. 135]. Intermittent circular motion of the ratchet-wheel from vibratory motion of the arm carrying a pawl.