Loop Forming Sequence of Compound Needle

The held loop is shown on the needle stem in the running position. The hook and tongue elements move upwards to that a new yarn may be presented to the hook and hence feeding occurs. Both elements descend, although at different velocities, which causes the tongue to close-off the hook. Thus the held loop is free to leave the needle, knock over pulling occurs. The needle now returns to the running to complete the cycle. As the needle returns to its 

starting position, the hook and tongue elements once again move at different velocities resulting in the opening of the hook.