THE FRICTION CLUTCH
The driving shaft of the machine is in two sections: The shaft proper, and the short shaft that carries the driving pinion. This pinion meshes with the driving gear, the two shafts being held together by a taper pin. The driving pinion makes eleven revolutions to one of the gear, the ratio being 11 to 1.
The outer end of the driving shaft is hollow. Inside of the hollow shaft is a clutch rod and a spring. The spring fits against a collar on this rod and draws the rod inward. The inner end of the clutch rod is fastened by means of a long screw pin extending through a hole in the rod to a collar which encircles the shaft, the hole in the shaft being slotted, so that when the collar is moved the rod moves also. On the outward end of the shaft is mounted the friction clutch, the levers being fastened to the end of the clutch rod. The friction clutch is keyed to the hollow shaft, so when the clutch is turned it also turns the shaft.
Pressure on a forked lever fulcrumed to the base of the machine, one end of which encircles the collar and the other end touching the lower stop lever, holds the clutch out of action. When the pressure of the forked lever against the collar is released, the clutch spring expands and the clutch rod moves the collar inward until the leather buffers are pushed against the inner surface of the driving pulley, causing the shaft to rotate.
After the machine has made a complete revolution, a pawl on cam No. 10 contacts the upper stopping lever and through the lower stopping lever forces the forked lever against the collar, throwing the friction out of action.