Cam 1 is rigidly attached to gear 4 and rotates about fixed axis A. Follower 2 oscillates about fixed axis B and has round lug b which slides a long the workinig surface of cam 1. The contour of cam 1 i s a long two symmetrical Archimedean spirals. Follower 2 has slot d which guides thread a. Thread a is wound on spool 3 which rotates about fixed axis C-C. The contour of cam 1 enables even layers of thread to be wound on the spool.
$3163$SmC,FD$