In
1854 the four motion feed, patented by Allan Wilson solved the problem
very neatly. Nearly all manufacturers have adopted this method of
moving the work along after each stitch.
A
spring loaded presser foot pushes the material against a toothed
rack which emerges through a small slot in the work top. A cam (or
sometimes two) moves the rack up, forward, down and back. This moves
the cloth by a set amount after each stitch. The length of the stitch
can be reduced by preventing the rack from returning all the way
back so that the cam is not always touching the rack for horizontal
movement.
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