GB1398620A - Sewing machines - Google Patents

Abstract

1398620 Sewing machines A M F Inc 2 Nov 1973 [14 Nov 1972] 52550/72 Heading D1G In a sewing machine with a slot 19 in a sewing surface, conveyor belts 10 and 11 for feeding material to and from the slot, a sewing head 13 for stitching material through the slot and transport means 21/22 for moving the stitching head parallel to the slot, sensing means are provided to sense the lateral edge of a piece of material to control the transport means to sew the material a predetermined distance from the edge. Sensing means are also provided to start the stitching and the second belt which preferably travels faster than the first belt 10 to tension material. material. In use, with a chain stitching machine, when a piece of material on the moving belt 10 cuts the infra-red light from a source 29 to anticipator and switching cells 50 and 51 the stitching motor 42, second belt motor and the head moving motor are started. Two further lamps 52, 53 are positioned on the sewing head light from which is reflected from an anvil 12 between the belts or a reflective strip 57 thereon onto respective photo electric cells 58, 59. As the material reaches the slot 19, it cuts-off light to the cell 58 thereby switching control of tracking to the cell 59 which senses the side edge of the material to stop the head moving motor with the needle the desired distance from the side edge. The cell 52 detects the trailing edge of the material to switch off the stitching and secondary belt motors after a delay. If desired a thread chain cutter may be provided. The pieces of material are held against the belts by air drawn through them and the perforated belt supports into chambers 14 and 15 by a blower 16 and raised at the slot 19 and and the anvil 12 between the belts by the effect of a plate 30 (Fig. 7) and air rising between the belts. The eyed looper 64 is oscillated from right to left behind the needle and back in front of the needle 32 by a link 72 driven through an effective bellcrank from an eccentric 69 on a shaft 66, the looper 64 being moved backwards or forwards at the end of its sideways travel on a pivot 67 mounted on a shaft 73 which is oscillated through a drive yoke 77 by a further eccentric 76 on the shaft 66. Thread is supplied to the looper via a guide tube 75 and a take-up mechanism 83 to 86, including a pair of cam discs 85, from a supply. A pair of oscillatory needle guards 79, 82 are also provided.