Patent GB-791980-A (GB)
IPC: D05B37/04
Abstract: 791,980. Sewing machines. UNION SPECIAL MACHINE CO. May 15, 1956 [Sept. 30, 1955], No. 15042/56. Class 112 In a sewing machine comprising a main driving shaft, a work-supporting surface, a plurality of needles mounted for reciprocation through said surface. Surfacethread-laying fingers co-operating with the needles above said surface, and mechanism for trimming the edges of the work in advance of the needles, separate connections are provided from said shaft for driving said fingers and said trimming mechanism. Multi-needle machines. The invention is shown as a modification in the machine described in Specification 709,531, the machine being of the feed-off-the-arm type having a horizontal portion 10 which contains a driving shaft 13 and from which a head 11 projects over the free end of a horizontal work-supporting arm 12 connected by a vertical portion (not shown) to one end of portion 10. Head 11 contains a presser bar 27 and a needle bar 24 which supports four needles 26 for co-operation with a looper mounted within arm 12, the needle bar being driven by a lever 18, 21 fixed to a rock shaft 20, and said lever being oscillated from a crank pin 15 on shaft 13. Surface threads, concatenating with a stitches; trimming: presser bars; presser feet. The presser bar 27, which carries a presser foot body 32, is slidably mounted in a sleeve 29 rotatably journalled in a sleeve 30 fixed to head 11. Sleeve 29 projects at both ends from sleeve 30 and is restrained from movement in an axial direction. A collar 72, fixed to the upper end of sleeve 29, carries a pin 74 journalled in one end of a pitman 75 the other end of which embraces an eccentric 76 on shaft 13. A yoke 105 has spaced bushes 104, 106 journalled on sleeve 29, and a pin 108, carried by an arm 107 projecting from yoke 105, is journalled in one end of a pitman 110 the other end of which is journalled on a crank pin 112 carried by shaft 20. Sleeve 29 and yoke 105 are thereby oscillated about the axis of the presser bar, and such oscillations are respectively transmitted to a pair of surface thread-laying fingers 52, 55, and to a trimming blade 87 which co-operates with a fixed blade 84, the arrangement being such that said fingers and blades can move vertically with respect to said sleeve and yoke, in order that they may follow the rise and fall of the presser foot. In the prior arrangement described in 'Specification 709,531, an oscillating sleeve, journalled on the presser bar, drives the blade as well as the fingers, and also moves. axially in response to the rise and fall of the presser foot. Fingers 52 and 55 are respectively fixed to pins 53 and 56 journalled in a plate 58 which is in turn journalled on the presser bar 27. An arm 60, fixed to pin 53, is pivoted at 61 to an arm 62 pivoted at 63 to plate 58. An arm 65, fixed to pin 56 is pivoted at 66 to an arm 67 pivoted at 68 to plate 58. A collar 69, fixed to the lower end of sleeve 29, has a downwardly extending finger 71 which passes through a notch in plate 58, finger 71 thereby driving plate 58 to oscillate said fingers, while allowing vertical movement of the latter. Blade 84 is fixed to the presser foot. Blade 87, which has a finger 89 overlying blade 84, is fixed in a channel member 90 carried 'by the lower end of a vertical rod 94 which is slidably mounted on an arm 98 and is spring-biased downwardly. Arm 94 depends from an arm 97 projecting from yoke 105. Arm 98 thereby drives blade 87 while allowing the latter to move vertically. The presser foot body 32 carries a sole plate having a pair of toes 32a, 32b which project in the direction of work feed and are spaced to accommodate the upturned edge of the work. Each toe carries a flat spring 32c for resilient engagement with the work. A curved plate 114, fixed to the upper surface of the sole plate, serves to direct the trimmings away from the needles. A plunger 82, mounted in body 32, is spring-biased downwardly and has a flat lower end which serves to retain the thread chain when the machine operates between work pieces. Rotation of the presser bar is prevented by the engagement of a pair of fixed fingers 34, 36 with the opposite sides of the body 32, and by the engagement of a finger 38, secured to the presser bar, with a fixed pin 39. A leaf spring 40 is formed at its respective ends with caps 41, 42 which fit over a fixed pin and the upper end of the presser bar. A fixed stud 43 passes through the middle of spring 40, and a knurled nut 43a screwed on said stud, serves to adjust the spring bias applied downwardly to the presser bar. One arm 50 of a bell crank lever underlies a finger 51 integral with finger 38, the other arm 48 being connected by a link 47 to one arm 46 of a bell crank lever the other arm 44 of which is connected to a treadle. Operation of the latter thereby serves to raise the presser bar. Needle guides. A plate 80, fixed flush with the undersurface of the presser foot, and a plate 78, fixed flush with the upper surface of the throat plate 77 carried by arm 12, are respectively formed with fingers 81 and 79 between which the needles pass. Specification 253,620 [Class 112], also is referred to.