(355) In beginning a set of cops the stop =W= is turned back to its proper position, which is determined by the size of the cop about to be spun. The frame =S= is then pushed forward as much as possible, and the chain is slipped on to the smaller portion of the bowl in =Y=. This allows the pendant =O= to fall a little, and its height subsequently is regulated strictly by the position of the fallers. During the outward run the horizontal arm =P=, which forms part of the pendant =O=, engages with the vertical projection on the frame =S= and causes it to move forward. The rack =R= being raised engages with the wheel =U= and rotates it, this movement being consequently communicated to the quadrant nut. Thus the latter is put into position for action during the next period of winding and any straining of the yarn is avoided. As the stroke of the rack is continued, the tongue =I= engages with the nut and causes the rack to drop out of gear with the pinion, and any further movement of the quadrant nut is avoided. It has been shown that the traverse of the latter is gradually diminished as the cop is built, and, in like manner, the inward motion of the stop =W= causes the engagement of the rack and pinion to be limited. This is a sort of “trip” motion very familiar to students of steam engine practice, and is well applied in this case. The slide =S= is drawn back into position by the engagement of the lower end of the pendant =O= with the finger =L=. A slight contact at first between these becomes a firm one by the backward movement of the finger when pressed upon by the pendant =O=, but it will be obvious that, if the latter is too high to move the finger =L=, the rack will remain untraversed until a sufficient depression of =O= takes place. It only remains to be said that once the nut =W= has been set at the beginning of winding, all that is required is for the minder to slip the loop of the chain on the right portion of the bowl in =Y=, and the motion acts automatically until winding is finished.
(356) A somewhat similar attachment has been recently introduced in France, and is the invention of Mons. Dubs. The author is informed by a trustworthy mechanician that the motion acts perfectly throughout winding, and it may, therefore, be well to give a brief description of it. As in the motion of Messrs. Dobson and Barlow, the regulation of the nut takes place during the outward run, and it is unnecessary to again detail the reasons for this course. The chief operating part of the mechanism is the rack finger =A=—shown in its position when in gear—which is hinged on a vertical rod or plunger =K=, sustained in a frame or bearing =S= fastened to the carriage. Referring to Fig. 181, the whole of the apparatus moves with the carriage and is self-contained. Attached to the faller is a connecting rod or link =B=, which is coupled to a hinged lever =O= formed at its outer end with a toothed rack or quadrant finely pitched. With this rack, which has two sets of stepped teeth, two detent catches =H= engage. The lever =O= is hinged to a plunger =L=, which has at its lower end a screwed shank fixed to a plate =F= also secured in the same manner to the plunger =K=. The inner end of the rack lever =A= has a hanging piece =D= which can engage with a catch =E= on the plate =F=, but which in the view is shown out of gear. The downward motion of the inner end of =A= is regulated by the stop screw =R=, and it is coupled by the chain =C= to the counter faller. The spring =M= constantly presses the inner end of =A= down, tending to raise the rack. When the various parts are adjusted the parts =F K= and =L= move together and simultaneously with the lever =O=.