Patent GB-766779-A (GB)
Title: Improvements in or relating to sewing machines
IPC: D05B27/18
Filed: 1954-03-22
Abstract: 766,779. Sewing machines. UNION SPECIAL MACHINE CO. March 22, 1954 [March 23, 1953], No. 8241/54. Class 112. Overhead scale-pan type machines.- In a cup-feed sewing machine, means for varying the amplitude of the intermittent feed-movement of the cups to change the length of stitch, and means for varying the elevation of the work to change the depth of seam, are controlled during continued running of the machine by a common operating member. The machine is especially adapted for sewing the seams of fully fashioned stockings, the stitches in the heel and foot being approximately 22 to the inch as against approximately 16 to the inch in the leg, and the former stitches being deeper than the latter. Feeding movement is imparted to the work by feed cups 64, 65, Fig. 8, the work first passing through an uncurler guide 140. A shaft 95 is adapted to be rocked by a knee pad 26, Fig. 1, the arrangement being such that angular movement of the shaft serves to vary the feed stroke of the cups for altering the length of stitch and simultaneously to raise or lower the uncurler guide in relation to the feed cups for varying the depth of seam. A needle bar 35, carrying a needle 35a, is reciprocated from a main shaft 34, Fig. 5. A first looper 38, is given combined reciprocatory and oscillatory movement from shaft 34, and a second looper 55 is oscillated from shaft 34. Feed cup 64 is carried by a shaft 66 attached to the housing 69 of a uni-directional clutch coupling such as described in U.S.A. Specification 2,494,006. A plate 70 is journalled on shaft 66 and is adapted to drive housing 69 in one direction and to rotate freely in the reverse direction, said plate having a ball-and-socket connection to one end of a coupling rod 74. The other end of the latter is pivoted to a ball headed pin 92 the shank of which is slidably disposed in a slot 79 formed in one arm 80 of a lever pivoted at 81. The other arm 82 of the lever is pivoted to a pitman 84 embracing an eccentric 86 on shaft 34. Rotation of the latter thereby serves to impart intermittent feeding movements to cup 64. Pin 92 is also pivoted to one end of a link 87 the other end of which is pivoted to an arm 94 fixed to shaft 95. Movement of the latter in the clockwise direction thereby serves to move pin 92 away from pivot 81 and so lengthen the stitches. An external arm 96 fixed to shaft 95 lies between a pair of adjustable stops 102, 110 and is biased by a spring-loaded plunger 99 to the position of maximum stitch length. Arm 96 is connected by a chain 29 to the knee pad 26, whereby it may be moved against the spring bias to the position of minimum stitch length. A gear 114 fixed to shaft 66 meshes with a gear 115 fixed to a shaft 116, the latter being fixed to one element of a universal coupling 117. The other element of the coupling carries a shaft 118, to the lower end of which is fixed the cup 65. Shaft 118 is journalled in a sleeve 119 carried by an arm 120 fixed to a shaft 121 to which is also fixed a bell-crank lever 122. One arm of the latter carries a finger 137 lying between a pair of adjustable stops 133, 134 for limiting the movement of the lever. The end 123 of the other arm embraces a groove in a rod 124 which is slidably mounted in an adjusting screw 127 carrying a U-shaped member 126. A spring 125 mounted on rod 124 between members 123 and 126 biases lever 122 clockwise to urge cup 65 against cup 64. A spring 130 mounted between the lower arm of member 126 and a collar 131 fixed on rod 124 biases the latter upwardly to maintain rod 124 free of the end 123. A cable 21 couples rod 124 to a pedal 20, whereby lever 122 may be turned counterclockwise for moving cup 65 away from cup 64. The uncurler guide comprises an arm 141 fixed to a sleeve 143 journalled in a sleeve 144. A pair of work-clamping members 145, 146 are respectively pivoted at 147, 148 to arm 141, a spring 149 interposed between said members biasing their lower, work-guiding ends against a blade 150 carried by arm 141. The latter may be secured in the lowered, operative position or in raised inoperative positions by a latch 151 which is operated by a handle 152 and is of the kind described in U.S.A. Specification 2,131,007. Sleeve 144 is secured by a clamp 155 to a slide 154 movable vertically between a pair of guides 156, 157, downward and upward movement of the slide being respectively limited by a pair of nuts 163, 164 which are carried by a screw 160 and straddle a finger 161. The slide is biased downwardly by a spring 158 mounted between clamp 155 and guide 157. A lever 166, fulcrumed at 167, has one end pivoted at 168 to the slide and the other end embracing a rod 169. A head 172 on the lower end of the latter is maintained in engagement with an arm 173, fixed to the feed-adjusting shaft 95, by means of a spring 171 interposed between lever 166 and a collar 170 on the upper end of rod 169. On rotation of shaft 95 in the stitch-shortening direction, arm 173 moves rod 169 downwardly to compress spring 171 till lever 166 moves slide 154 upwardly against the bias of spring 158, thereby raising the uncurler guide and increasing the depth of seam. A stitch finger 187, Fig. 10, having a nose 188 over which the overedge stitches are formed, rests on a support member 181 secured to the lower end of a fixed post 179. The stitch finger is provided with a pair of pins which project downwardly through respective holes. The support member is biased against the latter by a leaf spring 190, the stitch finger also bearing against an extension 197 of a plate 198 secured to the bearing sleeve 119 of cup 65. A post 194 rises from the stitch finger and is formed with a slot 195. Pivot 148 of the uncurler guide is formed with an extension 196 which .is adapted to extend through slot 195 when the uncurler guide is in the operative position and, by co-operation with the upper end of the slot, to lift the stitch finger when the uncurler guide is raised for deepening the seam. Means are provided for imparting a puller action on the work after it has passed through the feed cups and comprise a bracket 202, Fig. 13, secured to the machine frame and carrying a serrated roller 200 engaged with the serrations on cup 64. Movement thereby imparted to roller 200 is transmitted to a second roller 201 also carried by the bracket. A serrated roller 206, which co-operates with roller 201, is mounted on the end of a rod 207 slidably carried by a sleeve 209 fixed to a bracket 210 mounted on plate 198, spring 213 within the sleeve biasing roller 206 against roller 201. A guide arm 217, provided on the pivot of roller 206, extends towards cup 65. In a modification puller means such as described in U.S.A. Specification 2,412,894 are used, said means comprising an arm pivoted to cup 65 and biased against the latter by spring means, the arm carrying a vertical plate which bears against cup 65 and extends between the cups to direct the work towards the point of contact of the plate and cup 65. Lubricating.-The sewing machine comprises a vertical standard 30, Fig. 5, from which an arm 31 projects to provide for free movement of the work, a removable cover 32 extending over the standard and arm to form with a horizontal portion 33 in the standard a lubricant-tight enclosure for the main operating parts of the machine. The main shaft 34 carries a disc which dips into the lubricant to create a lubricant mist in said enclosure during operation of the machine. Stands.-The machine is mounted on a table top 11, Fig. 1, carried by a pedestal 12 having a floor-engaging base 13. An electric transmitter 14, such as described in Specification 416,461 [Group XXXV] is secured to the under surface of the table top and drives the machine by a belt 15. Treadles 18 and 20, for controlling the transmitter 14 and the swinging movement of cup 65 respectively, are mounted on the base. Knee pad 26, for controlling the stitch length and depth of seam, is carried by an arm 23 extending laterally from the pedestal. Specifications 448,259, 463,104 and 766,780 also are referred to.