rocking letter scale, letter opener and ruler, design Vilho Setälä
This letter scale tilts at a letter above 20 grams. The scale can also be used as a ruler and as a letter opener. In addition, it seems an excellent stabbing weapon, if necessary. It is a design made by Vilho Setälä from Helsingfors in Finland. A German patent was granted on December 22, 1928, with number DE504103. The patent was issued on July 31, 1930. On this scale underside is Pat.A453-46. No idea in which country that can be found. I do not know the way in patent Finland. The tilting limit is stated on the tilt letter scale: 20 grams.
Below some more pictures of this Finnish rocker.
the patent drawings
