Patent GB-1078796-A (GB)
Title: Sewing machines
IPC: D05B57/00
Filed: 1966-03-10
Abstract: 1,078,796. Sewing machines. SINGER CO. March 10, 1966 [March 12, 1965], No. 10515/66. Heading D1G. The respective drive means for the needle and looptaker of a sewing machine are arranged in untimed relationship. The speed of operation of said drive means may be controllable relatively to each other. Means may be provided for storing a needle loop, seized by the looptaker, out of range of subsequent seizure by the looptaker on continued operation of the machine. A frame 98, carrying a needle 57, is slidable on a fixed rod 90, and is engaged with a block 104 pivoted at 105 on a gear wheel 106 rigid with a driven shaft 50, for imparting reciprocation to frame 98. Gear 106 meshes with a gear 121 carrying a pivoted block 119 engaged in a slot in a pivoted arm 113 for oscillating the latter, the free end of arm 113 having a thread take-up eye 115. A presser bar 130, carrying a presser foot 135, has a forked upper end 137 slidably embracing a fixed pin 138, and is pivoted intermediately on a pin 139 carried by one arm of a two armed lever, the other arm of which abuts a crank pin 145 of a shaft 146 turnable by a handle 147 for raising the presser bar. An arm 160, pivoted at 161 to the presser bar, is bifurcated to support the downturned face end 158 of a bar 157 pivoted at 191 to one arm of a two-armed lever 189. Bar 157 is connected by a link (154) to a leaf spring 150 for biasing the presser bar downwardly. A roller 162, engaging spring 150, is journalled in a carriage 163 movable by means of a handle 167 in a slot 164 in a fixed bar 165 for varying the force exerted by spring 150. A feed bar 170, carrying a feeding foot 176 embracing the presser foot 135, is formed intermediately with an axial slot 179 embracing pin 139, and has a forked upper end (174) slidably embracing a block (181) pivoted on a pin (182) at one end of a link (183) pivoted at its other end to a pin 184 on a pitman 185. The latter is pivoted at 188 to the other arm of lever 189, and has an aperture embracing an eccentric 187 fast with shaft 50. Eccentric 187 thereby imparts longitudinal movements to pitman 185 and bar 157, and imparts oscillatory movements to pitman 185 about pin 188 whereby block (181) rises and falls in forked end (174). A block (192), pivoted on pin (182), is slidable in a groove (193) formed in a member 194 turnable about a pin 195 by means of a handle 196. The inclination of groove (193) thereby determines the extent and direction of the feeding stroke of foot 176, During the forward movement of bar 157, link 160 is swung clockwise to engage an abutment 180 on feed bar 170 for applying downward pressure to the latter during the feed stroke. During rearward movement of bar 157, link 160 is swung counterclockwise to disengage from abutment 180 during the return stroke of the feeding foot. Manipulation of handle 147 serves to raise both presser bar 130 and feed bar 170. The machine column 13 is supported on a base plate 12. Shaft 50 is driven by a belt 56 from a motor 52 supported on a bracket 53 projecting from column 13. A plate 14, secured to plate 12, supports a vertical-axis motor 16, to the shaft 17 of which is secured a rotary hook body 20 surrounded by a casing 23 secured to plate 12. A plate 25, secured to the upper end of casing 23, has a raised, worksupporting portion 29 having a needle-passing hole 30. The rotary hook body 20 is formed with a central boss 206 surrounded by a cylindrical wall 202 to define an annular recess 207 for receiving the needle 57. The upper end of wall 202 is notched to form four loop-seizing beaks 205. A bobbin case 40 has a peripheral flange 226 which rests on wall 202, and is formed with a central post journalling a bobbin 41. Flange 226 is cut away at two adjoining surfaces 242, 245. A leaf spring 215, carried by a bar 212 secured to casing 23, engages surface 245 to bias a shoulder 243 on the bobbin case against a shoulder 218 of an aperture 217 in plate 25. The undersurface (21) of the bobbin case is formed with a recess having a circular edge which extends beyond boss 206 and a straight edge (251) parallel to surface 245, whereby surface (221) engages boss 206 beyond edge (251). A leaf spring 42, carried by plate 25, engages the bobbin to bias flange 226 against wall 202 and surface (221) against boss 206. The arrangement is such that one of the beaks 205 is able to take the thread loop from the needle during the period when said loop is suitably presented. If said period corresponds to the turning of shaft 50 through 30 degrees, then the ratio of rotation of shaft 50 to shaft 17 should be 1 to 12 for 1 beak, 1 to 4 for 3 beaks, 1 to 3 for 4 beaks and 1 to 2 for 6 beaks. The limit of the taken loop extending to the needle eye passes under the bobbin case and is halted at the edge (251). The limb extending to the work passes upwardly and lodges on a peripheral ledge (260) formed in the bobbin case. On operation of the thread take-up, the bobbin case is raised to release the lower limb, and the upper limb is drawn successively past the spring 42, the spring 215 and the abutting shoulders 218, 243.