Device of detecting cloth feeding amount in sewing machines

Abstract

Abstract In preparing for the sewing of fancy or complicated stitch patterns, on a sewing machine provided with a feed dog able to feed sewn material both forwards and backwards and also provided with a transversely shiftable needle for implementation of zig-zag effects, the sewing machine is operated as if to sew the stitch pattern desired, but without any cloth actually present beneath the machine's needle. The movement of the machine's feed dog and the transverse or zig-zag shifting of the machine's needle are both detected by transducers which generate corresponding electrical signals. These signals are processed and converted into a form suitable for application to the x- and y-inputs of an x-y recorder, which then generates a display of what the thusly simulated stitching pattern will look like when actually stitched on cloth. The transverse shifting of the machine's needle is readily detected and unproblematic because of its definiteness. The cloth-feeding operation performed by the feed dog, however, is problematic, due to the inherently indefinite operation of cloth feeders, uncontrollable displacements of sewn material during feed-direction reversals, etc. Accordingly, to generate the data needed for simulation of cloth feed action, the invention utilizes an attachment which includes endless belts physically engaged by the feed dog and used to simulate the presence of cloth being sewn. All this makes it unnecessary to waste workpieces during the trial-and-error work involved in preparing for the stitching of a complex or fancy stitch pattern.

Inventors

• 👤 Fumio Shimazaki

Bibliographic Details