| In early machines the work had to stop frequently to move the cloth. In some cases the material was clamped or pinned to a bar to enable a greater length to be sewn without stopping. Curves were difficult to achieve. |
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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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| I have one machine with the teeth on the bottom of the needle bar which moves in the four directions to advance the material. This is more expensive to engineer but it does mean that the cloth can move whilst the needle is down. |
