GB980568A - Improvements in chain stitch sewing machines - Google Patents

Abstract

980,568. Sewing machines. G. M. PFAFF A.G. June 6, 1963 [June 13,1962], No. 22488/63. Heading D1G. The threaded looper of a chain stitch sewing machine is releasably locked to a carrier and is automatically moved from a withdrawn position, at which it is accessible for threading, to its operative position upon the starting of the machine. The looper 32 on its support 31 has a shaft 31<SP>1</SP> rotatably mounted in the carrier 22, a spring 43 urging the looper from the operative position shown in Fig. 2 into the threading position shown in Fig. 3 when a locking lever 36 is manually operated to withdraw its lower end from a notch in a disc 34 secured to the shaft 31<SP>1</SP>. Further movement is prevented by the abutment of the looper and a cam member 45 adjustably mounted on the machine bed. Whenthe machine is startedthe looper moves to the left as seen in Fig. 3, the face 49 of the fixed cam rotating the looper back to its operative position where it is held by the re-engagement of lever 36 with the notch. If the looper is at a position other than the end of its return stroke the face 50 of the cam 45 first limits the looper rotation and then returns it to the operative position during the return stroke. The looper movement is derived from eccentrics 15, 30 on shafts 8 and 12 respectively. The hinged rod 16,18 of eccentric 15 is connected to carrier 22 by the member 21 pivoted at 24 to the support 25. This support is oscillated by the shaft 26 which is connected to the rod 29 of the eccentric 30.