Fig. 1569.
The shaft of the driving pulleys (p p′ and p′′, [Fig. 1567]) drives a pinion operating the gear wheel w, upon the face of which is a serrated internal wheel answering to a ratchet wheel, and with which a pawl engages each time the direction of pulley revolution (or, which is the same thing, the direction of motion w) reverses, and causes the pawl and the shaft, to which the plate p, [Fig. 1569], is fast, to make one-half a revolution, when the pawl disengages and all parts save the wheel w come to rest.
From this plate p the feed motions are actuated, and the tool is lifted during the back traverse of the work table by the following mechanisms.
Fig. 1570.
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