This is a transverse shuttle machine, which means that the shuttle moves back and forth horizontally, rather than vertically. The mechanics of how the shuttle travels is constructed differently compared to a vibrating shuttle machine.
When I was inspecting the mechanics of the shuttle area, I saw a pin out of place. This was actually a kind of a spring to help the lower feed dogs retract below the needle plate while stitching. All it took was a bit of thought and looking around!
Sewing With Nick 