Fig. 89. Bobbin in position in bobbin case—Method of threading
The bobbin case ([Fig. 87]), fixes to a stud in the centre of the hook. It is held in position, that is, kept from revolving with the hook, by means of a stop pin, Q, fitting between a holder. The tension is obtained by a spring, R, which is regulated by turning a small screw, S, to the right to tighten and to the left to loosen. [Fig. 88] shows the bobbin case in position, with the holder raised ready for taking it out of the machine. [Fig. 89] shows the bobbin in position in the bobbin case and method of threading, and [Fig. 91], the direction the cotton should draw off the bobbin when it is in the machine. It will be noticed that the cotton pulls in the opposite direction to which the hook travels, as shown by an arrow in [Fig. 88]. The bobbin case holder ([Fig. 91]), should prevent the bobbin case from revolving with the hook. As parts wear, the bobbin case is liable to slip past the holder, causing the cotton to be stranded and broken. When such is the case the holder should be bent as shown by ([Fig. 92]), but it must not fit so tightly against the bobbin case as to cause the cotton to become trapped. The holder is held rigid by means of a catch and spring T ([Fig. 88]). Should the catch or holder become worn, fit new parts by driving out the pins U and V. Any sharpness or roughness on the forked part of the holder should be removed. Should the stop pin Q ([Fig. 87]) become loose, it should be soldered and well cleaned with an emery cloth. The centre tube of the bobbin case should also be kept quite firm. Should it become loose, place it over some hard substance, rivet it until tight, and thoroughly smooth with very fine emery cloth.
Fig. 90. Direction cotton should draw off
Figs. 91 and 92. Bobbin case holders