GB639516A - Rotary take-ups for sewing machines - Google Patents

Abstract

639,516. Sewing-machines. SINGER MANUFACTURING CO. Aug. 11, 1948, No. 21161. Convention date, May 12. [Class 112] Lock-stitching by eyed needles.-A rotary take-up, for a machine having a rotary hook rotating more than once for each reciprocation of the needle, comprises a single thread-engaging element revolving at a varying radius about a driving shaft. The element is preferably carried by a planetary wheel revolving around a fixed sun wheel and means are provided to counteract rotation of the element about its own axis and to adjust the timing of the device in relation to the rotation of the hook. The take-up element is arranged to be at its minimum radius and minimum angular velocity when the needle is at its lowest point and at its maximum radius when the thread loop is passing between the bobbin-case and its rotation-restraining finger. In the form shown, a disc 57, fixed to a shaft 46 running at the same speed as the needle-bar shaft but placed above the latter, has a bearing 58 for the hub of a planetary gear 60 which runs round a fixed sun gear 54 of the same size. A plate 63 has a stem 62 non- rotatably secured in an axial bore 61 in the gear 60, and has an eccentric pin 66 forming a bearing for a sleeve 67 integral with a pinion 68, the plate 63 having a balance weight as shown ; the sleeve 67 projects through a cover 70 fixed to the plate 63, and the eyed thread-engaging element 45 has a pin 73 which fits frictionally in the bore of the sleeve. An internallytoothed ring 69, with a pitch diameter double that of the pinion 68 and meshing with the latter, is fixed in a seating 82 in the disc 57. The element 45, being in effect eccentrically-mounted on the gear 60, undergoes a cyclic variation of radius about the shaft 46 as the disc 57 carries it about that shaft, one cycle corresponding to one revolution of the disc ; the plate 63, during one such revolution, rotates on its axis through two revolutions relative to a fixed direction, but the pinion 68 is, during the same period, rotated by engagement with the ring 69, through two revolutions in the opposite direction relative to the plate 63 so that the element 45, carried by the pinion, does not rotate at all. The sun gear 54 is mounted rotatably on an extension 56 of a bearing 49 for the shaft 46, and is moved thereon, to adjust the timing of the device, by a finger-lever 50. The device is surrounded by a member C forming part of the machine frame, and a cover-plate 74, fitting in the member C and round the cover 70, is fixed to the disc 57. Rotation of the bobbin-case of the rotary hook is prevented by a bent-up lug projecting laterally from a finger fixed to one side of the machine bed (Fig. 11, not shown), Specification 639,530 is referred to.