Electronic sewing machine with back stitching system

Claim 1

In a sewing machine, an arrangement for forming patterns made up of stitches, comprising, in combination, a static memory having a plurality of outputs and a plurality of address signal inputs and comprised of a plurality of storage units connected to said inputs and outputs and addressable by address signals applied to the address signal inputs of the memory; stitch-forming means provided with a plurality of stitch control signal inputs connected to the outputs of the memory and operative for producing any of a plurality of different stitches in dependence upon the signals produced at the outputs of the memory; addressing means including an addressing counter operative when activated for applying the address signals to the address inputs of the static memory to read out stitch control signals from the memory; synchronizing means operative for activating the addressing means in synchronism with the operation of the stitch forming means; and back stitching means manually operated to change the address signals in accordance with the required back stitches, said back stitching means including a manually operated switch, an address memory operative, when the manually operated switch is operated, to cause the addressing counter to count down the storage units of the static memory by the address signals, and signal inverting means connected between the static memory and the stitch-forming means to invert the stitch control signals read out from the static memory.