This invention relates in general to sewing machines and in particular to a new and useful device for sensing the thickness of the material being sewn at a stitching point.
German Pat. No. 33 23 214 discloses a sewing machine that has an optoelectronic sensing device to detect changes in the position of the material. All that the prior art solution does is to give off a switching pulse when there is a transition in material positions, and it cannot determine the actual height differential of the approaching difference in thickness.