Sewing machine with an electronic pattern stitch control system

Claim 1

In a cyclically operating sewing machine, in combination, a static pattern memory having address inputs, data outputs and comprising a plurality of addressable storage locations storing pattern data for the constituent stitches of a plurality of selectable patterns; user-operated pattern-selector means operative when the user selects one of the selectable patterns for generating a pattern-identifying signal identifying the pattern thusly selected; addressing means connected to the address inputs and operative for addressing successive storage locations of the pattern memory by the application of successive address signals to the address inputs of the memory at a frequency greater than the frequency of the cycles of machine operation, whereby to cause the pattern data stored in successive storage locations of the memory to be produced at the data outputs of the memory, and including comparing means connected to the data outputs of the memory and to the pattern-selector means and operative for comparing the data successively produced at the data outputs of the memory against the pattern-identifying signal to automatically ascertain whether the data at the data outputs does or does not belong to the selected pattern and, if the data does not belong to the selected pattern, causing the addressing to continue until data which does belong to the selected pattern is produced at the data outputs, whereby during individual cycles of machine operation successive address signals are applied to the address inputs at high speed until data which does belong to the selected pattern appears at the data outputs; and stitching-forming means connected to the data outputs and responding to the data produced at the data outputs.