The Singer Model 20 SewHandy Machines were manufactured by Singer Sewing Machine Company. There is a good reference page on their history at Singer Miniature Toy Chain Stitch Sewing Machines.

They were first introduced in 1910.  Although marketed mainly as children's machines, their brochures also refer to them as being for "light household duty". At this point, I have used them both for doll clothes, and for more household-practical sewing projects.  I plan on adding posts and videos to this blog as I use my six Models 20 machines for more and more projects.