Patent GB-779132-A (GB)
Title: Machines for and methods of producing seams and products thereof
IPC: D05B1/20
Filed: 1955-02-17
Abstract: 779,132. Sewing; sewing-machines. UNION SPECIAL MACHINE CO. Feb. 17, 1955 [June 2, 1954], No. 4736/55. Class 112. Seams. A plurality of work-pieces are united by a plurality of closely-adjacent lines of double-loop stitching with the stitches of adjacent lines staggered so as to provide the effect of a single line of stitches of a length equal to a fraction of that of any one of the lines of stitching, and a simultaneously-formed spaced line of stitching extending over the edge of at least one of the work-pieces. The overedge stitching may be formed of two, three, or four threads. Fig. 23 shows the application of the seam to the joining of two work-pieces 18, 19 of which the former has had a line of two-thread overedge stitching 21 applied to its edge. A similar line of overedge stitching 25 is applied to the edge of the other piece 19 simultaneously with the formation of two lines of double-loop stitching 22 connecting the pieces 18, 19 ; these two lines, shown separated for clarity, are actually substantially on the same line, and the stitches of the two lines are staggered. Multiple-needle machines; overedge stitching; looper-thread take-ups. A machine for forming a seam as described above, with overedge mechanism similar to that of Specification 691,894, is shown in Fig. 1. The needleholder carries two needles 64 arranged in a line substantially parallel to the line of feed and spaced at an odd number of half stitch lengths, for co-operation with threaded loopers 67 actuated in known manner to produce double-loop stitching, and a third needle 66, spaced laterally and rearwardly from the needles 64, for co-operation with the overedge looper 96 and looper 84. The mechanism for actuating the loopers 84, 96 is arranged in a housing 50 fixed on the bed of the machine; the axis of the rod carrying the looper 84 may be inclined to the vertical plane containing that of the rod of the looper 96, as in the arrangement shown, or may be parallel to this plane, in which case the latter rod is placed somewhat higher than is shown. The rock-shafts 91, 103 through which these loopers are actuated may be extended through one wall of the housing 50 to carry take-up arms engaging the respective looper threads between pairs of spaced fixed guides. In a modification a fourthread overedge seam is used, the loopers 84, 96 and the housing 50 with their actuating mechanism being replaced by a fourth needle spaced laterally from the needle 66 to pass just outside the edge of the work, a looper similar to 67 for co-operation with both these needles, and a device (see below) for laying a thread on the surface of the work for concatenation with the threads of both needles. Trimming. The work is trimmed in advance of the needles by an edge on the end of a bar of angle section inclined upwards to the right of the work-edge and co-operating with a fixed blade lying parallel to the line of feed. In one form of the mechanism, Fig. 8, the angle-bar is clamped by a plate 150 to a block 146 which is adjustable laterally of the line of feed in a dovetail slot in the end of an arm 137, the block being held in adjusted position by a clamping plate 147 thereon engaging the arm. The arm 137 is pivoted to a fixed block 139, and is prevented from moving away from the fixed blade by a fixed guide 142 ; it is actuated by a link 135 from a slotted arm on a shaft 129 which runs along the back of the machine arm 52, Fig. 1, and is oscillated from the main shaft 54 through a crank-actuated pitman 126 and lever 128. In another form, Fig. 16, the moving blade 240. is arcuate and is carried by an arm 242 oscillated by a connection 248 from an eccentric on the main shaft. Surface threads, attaching. A device for laying a surface thread for concatenation with the threads of two laterally-spaced needles comprises a finger 207, Fig. 16, secured to a sleeve 210 oscillated about the presser-bar 211 by an arm 216 and link 214 from an oscillating shaft 217 corresponding to the shaft 129 for actuating trimming mechanism (see above). Feed by dogs and by devices engaging upper surface of work. In the machine shown in Fig. 1 feed mechanism similar to that of Specification 687,812 is used. A different mechanism is shown in Fig. 16, comprising a lower feed-dog 223 on a feed-bar 225 and an upper dog 224 carried by a post on a feed-bar 229. Both feed bars are connected to a rocker 227 oscillated by an eccentric on the main shaft connected to an arm 232 fixed to the rocker, as described in Specification 687,812. Lifting movements are imparted to the feed-bars by separate eccentrics on the main shaft connected to arms on the feed-bars, the arm 235 on the feed-bar 225 being shown; a yielding connection, comprising a spring 229a, Fig. 14 (not shown) is provided between the feed-bar 229 and the arm corresponding to arm 235 to maintain the arm in abutment with a stud on the underside of the feed-bar. Specification 779,133 also is referred to.