The earliest sewing machine - patented by Thomas Saint in 1790.
Saint's contribution was not made public until 1874 when William Newton Wilson, himself a sewing machine manufacturer, found the drawings in the London Patent Office and built a machine which worked following some adjustments to the looper.

The handle turns a single drive shaft running horizontally across the top of the machine. Five pegs are fitted at right angles and rotate with the drive shaft. The longest peg, nearest the handle, engages with a large toothed wheel once every turn. This moves the wheel around intermittently to move the work table to the right slightly after each stitch. Clamps fixed to the top of the work table hold the material.
These photographs were taken from the model in the science museum - thanks go to Ben Russell, curator.

Details of the top of the needle bar are shown opposite. As the shaft rotates two (green on the sketch) pegs move a "Z" shaped bracket up and down to work the needle bar.
The other (blue on the sketch) pegs engage a plate fixed to a vertical rod causing it to rotate to and fro. This moves a roller on top of the work surface and the looper underneath.

Labeled sketch of machine.
Labeled sketch of the top of the needle bar arrangement.


The needle is preceded by an awl (not fitted in the picture) which first makes a hole. This would be necessary in order to protect the thread as it was forced through the leather. It has been said that Saint may not have actually constructed a working example of his machine. This seems unlikely to me. He got too many features right. Saint was a cabinet maker who could easily make and modify such a machine.

So, in 1790 Thomas Saint had invented a machine with an overhanging arm, a feed mechanism (adequate for the short lengths of leather he intended it for), a vertical needle bar and a looper.