Patent GB-260265-A (GB)
Title: Improvements in or relating to festoon sewing machines
IPC: D05C7/06
Filed: 1926-10-20
Abstract: 260,265. Union Special-Maschinenfabrik Ges. Oct. 21, 1925, [Convention date.]. Multiple-needle sewing-machines ; chain stitching and double loop stitching ; needles, driving: cords, attaching.-In a machine for festoon sewing the work is fed by dog and the stitch-forming devices, which form chain stitches with multiple needles and a concatenated covering thread are moved at right angles to the direction of feed to produce the curvature of the stitch line. An associated trimming device is provided with means for laterally displacing partially rotating it to follow the contour of the stitch line and trim off surplus material. The stitch-forming devices comprise a needle-bar 11 carrying a pair of needles 66, a thread-laying finger 12, associated with thread-guides 17a, 18<a> and a threaded looper 21. The needle-bar is driven from a shaft 4, geared to the main shaft 2, through a crank 7, link 9 and bolts 8, 8a. The thread-laying devices are actuated from the needle-bar 11 through diagonal teeth 13 on the needle-bar meshing with diagonal teeth 14 on a shaft 15 on which is mounted the supporting arm 16 for the finger 12 and arms 17, 18 carrying guide-eyes for the thread. The thread for the under looper passes through a pair of cane-operated nippers 22, 23 and over a take-up 24 to the looper 21. The looper is actuated by an eccentric 33 through a link, a two armed lever 34, 34a and a link 35 connected to the lever 36 on which the looper is mounted. The needle-avoiding movement of the looper is effected by an eccentric 40 engaged by a jaw 39 on a pivoted frame 38 which carries the lever 36. An auxiliary looper 41 for spreading the loop formed by the under thread is driven for longitudinal movement by a crank-pin 42 on the shaft 2 and mechanism comprising a link 43, double lever 44 and shaft 45 connected to the holder 46 of the looper, the transverse movement being given by an eccentric 47 embraced by a bifurcated arm of the looper holder. Trimming or cutting. - The c,utting devices comprise an upper knife 48 carried by an arm 126 and a lower knife 106. The knife 48 is actuated from an eccentric 49 through mechanism including a link 50 adjustably connected to a lever 51, a shaft 52 and a lever 55 on the shaft having a connection through a universal joint and a collar with the shaft 54 of the knife. Needles, vibrating laterally-The movements of the stitching and cutting devices to produce the curved stitch line are effected by cams 115, 116 driven by a worm gear 117, 120 and tracked by levers 69, 86, and 100. The lever 69, engaging a cam groove 68, actuates a rod 72 connected to a sliding block 75 carrying the bearings for the looper and the stitch-plate 67. The lever 69 is mounted on the inner shaft 65 of three concentric shafts 65, 101, 85, and the other end of this shaft carries a lever 76 connected by mechanism 77 - - 81 to a sliding rod 82 to which is secured a bearing member 83 for the upper stitch-forming devices which are thus shifted synchronously with the looper. The lever 86 on the outer shaft 85 acts through rods 89, 90 and a rocker 91 to shift the lower knife support 88, a lever 95 at the upper end of the shaft functioning through a link 97 to move a sliding rod 96 which carries the bearing member 53 for the upper knife shaft. The relation of the knives to the line along which they cut is adjusted by means which cause a slow rotation along the curve and a rapid reversal at the cusp of the festoon and comprise the lever 100 connected to a spring-controlled rack 105 meshing with a toothed segment 110 carrying the lower knife. The upper knife is rotated by a rack 113 engaging a pinion 114 on the shaft 54 and actuated by a lever 102 on the shaft 101 of the lever 100. Feed by dogs.-The feed dog 27 is carried by an arm 30 and lever 29 to which oscillations are communicated by an eccentric 26 which reciprocates an arm 28. Vertical movement of the dog is effected by a cam on the main shaft on which the dog rests. Stitches and seams.-The seam produced is of the form shown in Fig. 22, the concatenation of the various threads being as shown in Fig. 47.