Patent GB-998425-A (GB)
Title: Improvements in or relating to sewing machines
IPC: D05B1/20
Filed: 1964-04-14
Abstract: 998,425. Sewing machines. G.M. PFAFF. A.G. April 14, 1964 [April 18 1963], No. 15451/64. Heading D1G. Multi-needle machines, seams. A sewing machine is adapted to produce simultaneously a line of chain stitching and a line of overedge stitching parallel thereto and having a greater stitch length. As shown, Fig. 11, plies 93, 94 are interconnected by two-thread chain stitching 95, and the respective edges of the plies are covered by overedge seams 96 and 97, the stitch length of which is twice that of seam 95. Frames, stitch forming. A bed shaft 11, driven at the same speed as the arm shaft, is connected by a coupling 12 to a shaft 13 journalled in a housing 14 depending from the work support 1. Seam 95 is produced by a reciprocating needle 9 driven from the arm shaft, and a threaded looper 25, Fig. 3, carried by an arm 24 rigid with a shaft 23 adapted to oscillate and also to reciprocate axially. Shaft 23 and a pin 22 aligned therewith are journalled in housing 14 and are rigid with a rectangular frame 21 which journals a vertical pin 19. An inclined crankpin 15, on the end of shaft 13, passes diametrically through pin 19 and is journalled in the horizontal arms 16 of a crossmember 17, the vertical arms 18 of which journal pin 19. Seams 96, 97 are produced by oscillatory needles 73, 74 co-operating with respective unthreaded overedge loopers 41,42 and threaded under loopers 49, 50. The overedge needles and associated loopers are actuated from a shaft 30 driven by 2 to 1 reduction gearing 26, 27, 29, Fig. 4, from shaft 13. Loopers 41, 42 are carried by an arm 40 rigid with a shaft 39 adapted to oscillate and to reciprocate axially. Shaft 39 and a pin 38 aligned therewith are rigid with a rectangular frame 37 journalling a vertical pin 35. An inclined crank pin 31, on the end of shaft 30, passes diametrically through pin 35 and is journalled in the horizontal arms 32 of a cross member 33, the vertical arms 34 of which journal pin 35. Loopers 49, 50, Fig. 6, are carried by an arm 48 rigid with an oscillatory shaft 47 connected by a ball-leaded crank pin 46 and compound pitman 44, 45 to an eccentric 43 on shaft 30. Needles 73, 74, Fig. 7, are carried by respective arms 71, 72 rigid with respective shafts 69, 66 which are interconnected by a link 68. A crank 65 on shaft 66 is connected by a link 64 to one end of a member 54, the other end of which carries a pin 63 journalled in housing 14. A crank pin 55 on shaft 30 is journalled in one end of a link 53, the other end of which is formed with a slot 58. A pin 59, slidable axially in member 54, carries a crosspin 60 slidable in slot 58. The arrangement is such that member 54 oscillates to actuate the needles 73, 74, and the up stroke of the latter is of shorter duration than the down stroke. When the needles are fully raised, link 64 is aligned with pin 63 and link 64 is at right angles to crank 65, whereby the motion of the needles is respectively accelerated and retarded at the opposite ends of their strokes. Work feeding and supporting. A feed bar 84, Fig. 9, carrying a feed dog 86 disposed in an inclined throat plate 85, is connected at one end to a crank 83 on a feed advance shaft 79 driven by a variable eccentric, and is connected at the other end by a link 89 to a feed lift shaft 87. Reference has been directed by the Comptroller to Specification 948, 420.