Patent GB-213503-A (GB)
Title: Improvements in sewing machines
IPC: D05B27/18
Filed: 1923-02-01
Abstract: 213,503. Thompson, W. P., (Union Special Machine Co.). Feb. 1, 1923. Overhead sewing-machines.-In a machine for shaping and seaming a tubular knit stocking, Fig. 11, the trimming mechanism is automatically thrown into and out of operation at predetermined times while the sewing operation continues. Trimming or cutting; work guides; feed. One feed-wheel 15 is carried by a vertical shaft 17, Fig. 4, intermittently rotated by a clutch member vibrated by a link 19 which is adjustably connected to a slotted arm 20 of a shaft 21 oscillated from the main shaft. The other feedwheel 16 is carried by a shaft mounted in an arm 24 and intermittently rotated by a flexible shaft connection 25 from a shaft 26 driven from the shaft 17. A stationary trimming blade 28, Fig. 3, fixed in an overhanging arm 30 of a bracket 31 co-operates with a reciprocatory blade 29 which is adjustably carried by a slide 39, mounted in the bracket 31 and covered by a plate 41. The bracket 31 is vertically adjustable on the frame by means of an adjusting screw 38. The slide 39 has a depending lug 45 recessed to receive a spring 47 which bears against a vertical wall 48 of the plate 41. Pivoted to the lug 45 is a telescopic link, the parts 49, 50 being connected by a spring-pressed latch 52. The part 49 is pivoted to a continuously-oscillating arm 58 fixed to a shaft 59 carrying a lever 60, which is oscillated from an eccentric on the main shaft. The stocking is slipped on to a guide-frame 62, Fig. 1, pivoted for horizontal movement to a bracket arm 66, which is in turn pivoted for vertical movement to a fixed standard 69. The frame is held in normal position by a lug 71 thereon engaging a spring-clip 72 on the bracket 66. A stationary bracket-arm 64a, Fig. 4, engages the frame to align it with the feed wheels. A cam 114 is kept in contact therewith by a spring 117 pressing on the arm 118. A portion 115 of the cam gives the lever 112 its greatest outward motion, and, when this has passed, the nose 113 of the lever enters a hole in the cam 114 so as to hit the tail of a pawl therein, thus disconnecting the pawl-and-ratchet connection and stopping the cam 114. The cam 114 also carries a cam 73 which gives vertical movements to the work-frame for shaping the work. The length of feed depends on the pivot of the link 19 and the arm 20, Fig. 4. and this pivot is adjusted by means of a link 119 which is ball-jointed to the pivot and to an arm 121 fixed to a shaft 122. A spring surrounding the shaft 122 tends to rock the shaft so that the link 19 moves to an adjustable stop screw in the outer end of the arm 20. An arm 125 fixed to the shaft 122 is, engaged by an arm 127 integral with the arm 112 so as to hold the shaft 122 against actuation by its spring during trimming. The arm 118, Fig. 3, of the cam-lever 112 engages a depending arm 129 of the trimmer latch 52. In operation, a false seam is sewn on the stocking from the point 2 to the point a, Fig. 11. At this point, the arm 121 is pushed inward, thus shortening the feed, whereupon the ]ever 125, normally in the position shown in Fig. 4 pushes aside the arm 127, so that the lever 112 releases the cam-actuating pawl, and the cams 114, 73 will be actuated. The resultant depression of the arm 118 releases the latch 52 to actuate the trimming mechanism, while the movement of the arm 121 allows auxiliary thread tensions to be applied. The work is now trimmed and seamed to the point b, Fig. 11. When the cam 73 has almost made a complete revolution the nose 113 of the lever 112 rides up the surface 115, Fig. 3, so that the lever 127 releases the arm 125. The arm 121 immediately rocks to lengthen the feed and the nose 113 enters the hole in the cam 114, thus stopping the vertical feed of the work, while the consequent motion of the arm 118 releases the auxiliary thread tensions, and stops the trimming mechanism. A false seam is now sewn up the remainder of the stocking leg.