light concav letter scale
This letter scale by Ph. J. Maul has a concav reading chart. The frame is made of tin. This tin is pressed into profile. This results in a relatively lightweight and stiff frame. There are several designs of this letter scale. The form of the plate may differ. Of the larger scale with a 500 grams range, the tripod of the frame is executed differently. It is made of a thick strip of steel. the range of the letter scale shown is 0 - 250 grams. Other reach upto 500 grams. A smaller version has a range upto 100 grams. I don't know whether this design is protected with a patent.
concav logo
