Abstract: Apparatus for changing the stitch length of double lock stitch sewing machine while the machine is in operation. The apparatus including a first transmission having a variable transmission ratio that can be connected to the machine needle rocking assembly, and a second transmission having a variable transmission ration that can be connected to the machine feed dog assembly. Additionally, the apparatus includes an actuator connected to the first and second transmission that may be activated by a machine operator for synchronously changing the transmission ratio of the first and second transmission to effect change in the machine stitch.

Abstract: A walking needle chain stitch sewing machine having multi sewing heads laterally spaced apart from one-another, that includes upper primary drive shaft and secondary lower first and second drive shafts and mechanisms thereof for driving first and second needle-drive mechanisms, and that further includes other secondary lower third and fourth drive shafts and mechanisms thereof for driving first and second feed-dogs and mechanisms thereof, with the first and second drive shafts being connected to the primary drive shaft by respectively spaced-apart drive-belts each mounted between driving and driven gears, and with the third and fourth drive shafts likewise being connected to the primary drive shaft by respectively spaced-apart other drive-belts each mounted between other driving and driven gears.