Singer 601 - Bobbin Case Operations and Thread Tensions; Removing Bobbin Case and Bobbin; Threading the Bobbin Case; Replacing the Bobbin Case

3. The trimmer solenoid is energized when the sensor
plate n reaches a point shown in Fig. 58.
4. When the cam follower on the thread puller action plate slips into the recessed portion of the thread puller
action cam adjusting plate, the thread puller is activated to move through the loop (Fig. 59) to a point shown in
solid line in Fig. 60, and the needle and bobbin threads are positioned as shown also in Fig. 60. Simultaneously,
the thread puller action plate pushes the tension release action plate making its pin ride on the tension release
action cam. Immediately when the pin rides on the tension release action cam, the electronic command relayed
from the sensor platetC)( Fig. 61) cuts off the current supply to the trimmer solenoid. The above motion makes
the tension releasing cam rotate until just before the tension discs are released.
Fig. 59
Fig. 60
Fig. 61