Patent GB-450009-A (GB)
Title: Button sewing machine
IPC: D05B73/12
Filed: 1936-01-29
Abstract: 450,009. Sewing-machines. SINGER MANUFACTURING CO., Elizabeth, New Jersey, U.S.A. Jan. 29, 1936, No. 2612. Convention date, March 15, 1935. [Class 112] A machine for attaching flat buttons with two groups of stitches, e.g. four-hole buttons, has means for lifting the work clamp to break the sewing thread after each group of stitches is made, without disturbing the work relative to the work-positioning means. By this means, stay-buttons on the inside of the cloth are not disturbed. The machine is also applicable to sewing blind-stitched buttons without a stay-button. In attaching a four-hole button 91 with a staybutton 92 to a fabric 93, Fig. 15, by two parallel groups of stitches s<1> and without a diagonal crossover stitch, the button 92 is placed in the stay-button positioning pocket 40 in the guide plate 39 on the lower clampplate 36 which is locked in its lower rearward position on the throat plate 25 by the latch 86, Fig. 4. The main button 91 is inserted in the jaws of the levers 46 which are lowered with the button on to the fabric 93 which rests on the plate 39. This plate rests on the plate 36. The machine is then started and the needle 5 and loops 6 form the first group of chain stitches s<1> through the buttons 91, 92. The needle-vibrating cam 21 is so cut that the needle makes its last three complete strokes through the same holes to form knotting stitches. After the needle has risen from the work at the completion of the last stitch, one of the throws 69 in the cam 67 shifts the work clamp forwardly to the position shown in dotted lines in Fig. 4 whereupon one of the tripping points 83, Fig. 10, releases the stop-motion control rockshaft 75 and stops the machine. One of the projections 94 on the cam disc 22, Fig. 1, rides under and lifts the lever 95, just before the machine stops, to apply heavy tension to the device 96. When the machine stops, the corner 87 of the clamp-plate 36 is clear of the latch 86. When the operator exerts a pull on the rod 55 to raise the button clamp 45, 46 for the usual thread-breaking operation, the lower clamp-plate 36 and the stay-button plate 39 rise with the work, Fig. 15, without any disarrangement of the relative positions of any of the work-clamping elements. The stay-button 92 is not lifted out of its pocket 40 at this stage and the work clamp is lowered and the machine restarted to sew the second group of stitches s<1>. At the completion of this group, the work-clamp is returned to the position shown in Fig. 4, just before the stopping rock-shaft 75 is released by the other tripping point 83. In the position, the corner 87 of the clamp-plate 36 is under the latch 86 and the lower clamp plate 36 and stay-button positioning plate 39 are prevented from rising with the work when the button clamp levers 46 are raised by the operator to break the thread of the second group of stitches and for removal of the work. The operations are the same for blind-stitching a four-hole button 97, Fig. 18, to a folded edge 98 of the fabric. In this case, the workpositioning plate 39 is turned end-for-end to bring the folded-edge-positioning shoulders 42 into operative position above the sewing aperture 44 in the lower clamp-plate 36 and to remove the stay-button pocket 40 out of operative position. The main button clamp and the plate 36 are carried by arms 45, 35 pivoted independently on a common pivot pin 32 and resiliently connected for common or independent movement by a rod 47 passing through a hole 48 in the arm 45 and carrying a spring 49.