Patent GB-802833-A (GB)
Title: Compound stitching device
IPC: D05B1/20
Filed: 1956-05-14
Abstract: 802,833. Sewing machines. MAN-SEW CORPORATION. May 14, 1956 [May 31, 1955], No. 14892/56. Class 112. Multi-needle machines stitched seams. A sewing machine comprises a vertically reciprocable needle bar carrying a pair of needles, a looptaker disposed beneath a clothplate for co-operation with one of said needles to form a first rectilinear seam, drive means for said needle bar and looptaker, a pair of threaded loopers adapted to-operate with the second of said needles to form a second seam over the edge of the work, both loopers being supported for movement about axes located in a housing which is mounted on and is disposed entirely above the cloth plate, and drive connections between said loopers and drive means. In the arrangement shown, the first needle thread a, Figs. 18, 19, and looptaker thread b provide a lock stitch seam, and the second needle thread e and looper threads c, d provide an overedge seam which may assume the form shown in either of the said Figures by varying the respective tensions in the needle and looper threads. The needle bar 15 carries a needle 12 which co-operates with a rotary hook 11 to form the lock-stitch seam. The second needle 100 co-operates with a primary overedge looper 51 and a secondary overedge looper 60 which are mounted in a housing 35 disposed on the clothplate 1. The baseplate 34 of the housing is secured to the clothplate by screws which pass through holes 108 in plate 34 and aligned holes 109 in an adapter plate 32 which replaces the usual throat plate. A modified throat plate 98 is attached to plate 32 by screws which pass through holes 110 in plate 98 and enter threaded holes 33 in plate 32. Plate 98 is formed with a throat 102 for needle 12 and a throat 103, which is disposed to the side of and in front of throat 102, for needle 100. A slot extending from throat 103 defines a tongue 104 which supports the edge of the work during the formation of the overedge stitches, the undersurface of the tongue being tapered rearwardly to facilitate removal of the stitches therefrom. Plate 34 is cut away at 113 to provide clearance for the movement of the loopers. The presser foot 14 is formed with a hole 114 for needle 12, and with a notch 115 which is in register with tongue 104, the notch providing clearance for needle 100 and for the movement of the secondary looper 60. The feed dog 13 is modified to allow the passage therethrough of the primary looper 51, being provided for this purpose with two short serrated runners 116 and with a passageway 118 in the remaining long runner 116. Overedge stitching, oil reservoirs, cutting. Loopers 51 and 60 are respectively carried by oscillating shafts 52 and 61 which are angularly disposed with respect to each other and are journalled in one arm of the housing 35 which is L-shaped in plan and contains the drive mechanism for the loopers, for a thread-control member, and for a work-trimming mechanism. The housing is oil-tight and is provided with an oil cup 38 through which sufficient oil may be introduced to cover the working parts. A shaft 31, journalled in housing 35, is driven from the bed shaft 9 via gearing 23-29, a shaft 22 and a universal coupling 30. A shaft 45, journalled in housing 35, is driven from shaft 31 via gearing 43, 44. Shaft 52, carrying looper 51, is driven from shaft 45 by means of an eccentric 49, a pitman 56 and a crank 54. Shaft 61, carrying looper 60, and disposed angularly with respect to shaft 52, is driven from shaft 45 by a linkage comprising a member 65 which has a ball and socket connection with a crank 64 on shaft 61 and a pivotal connection with a pitman 66 embracing an eccentric 50 on shaft 45. An eccentric 42 on shaft 31 is connected by a pitman 79 to a crank 76 on a shaft 75 which carries a thread take-up and pull-off arm 81. Thread e is led from a tensioner 125 through guides 145, 146 to the needle 100. Thread d passes from a tensioner 124 through a guide 142 to the secondary looper 60. Thread c for the primary looper 51 passes from a tensioner 123 to a guide 126 which comprises parallel arms 128, 129 formed with two pairs of aligned holes 130, 131 and 132, 133, and a vertical tube 134, through which holes and tube the thread passes in succession, the thread then passing through holes 136, 138 formed in the respective arms of a right-angled rod 135. Arm 81 is disposed above the thread loop between holes 130, 131 and below the thread loop between holes 132, 133, the arrangement being thereby that arm 81 on its downward movement draws thread through the tensioner 123, and on its upward movement draws thread from the work to take-up the stitch. It is stated that either or both of the threads d and e may be passed through the thread 'guide 126 so as to be subject to the action of arm 81. An eccentric 41 on shaft 31 is connected by a pitman and crank to a shaft 85 which carries an arm 95 provided with the movable cutter blade for trimming the work along the line of feed. The fixed cutter blade 97 is carried by a block 99 which is secured to the throat plate 98. A guide 17 directs the trimmings into the opening 113 through which the loopers operate.