Patent GB-121991-A (GB)
Title: Sewing Machine.
Inventor: FAIRWEATHER WALLACE
IPC: D05B73/00
Filed: 1917-12-10
Abstract: 121,991. Fairweather, W., (Singer Manufacturing Co.). Dec. 10, 1917. Sewing - machines; frames; work supports. Relates to sewing - machines having the general construction of frame described in Specifications 121,330 and 121,331, and consists in the construction and arrangement of chain-stitch mechanism suitable for the form of frame and also modifications in certain parts of the frame. The intermediate bridge member extending at rightangles from the top of the standard 1, Fig. 1, is extended downwardly at its free end 4, forming an enlarged cavity 5 which is closed by a removable plate. The work-arm 7, which merges into the lower end of the extension 4, is trough shaped and comprises an upwardly inclined part. 7<x> and a substantially horizontal part at its free end. An extension piece 9 with an end wall 10 is secured to the lower wall of the work arm and supports one end of the throat plate 11. Hinged plates 14, Fig. 1<a> are provided to close the sides of the cavity between the wall 10 and the end of the work arm in which the looper is housed. The plates are normally held in closed position by a spring 14x, and may be opened to allow access to the, looper. The open side of the trough in the work arm is closed by a plate 8. Chain-stitching; needles, driving; governing needle thread; feed by dogs. - All the stitchforming and feeding devices are operated by a block 31 which is actuated bv a crank 32 on the main shaft 15. The needle-lever 24, journaled on the frame, has a rearwardly extending pin slidingly engaging a socket in the block 31, and is connected by a link with the rear end of the feedbar 53 pivoted to swinging arms 51. The feed-dog receives its reciprocating movements through a link 57, adjustably connected to one arm of a bellcrank lever 62, the other arm of which carries a pin 66 sliding in a socket 67 pivotally carried by the block 31. The looper-shaft 36 receives rocking and endlong movements from the block 31 through a link 41, connected between it ends to a crank-arm on the looper shaft and anchored to the frame by a link 47. The take-up for the needle and under threads consist of three arms 94, 95, 96, Fig. 12, adjustably secured to the block 31, and working in slots 101, 102, Fig. 9, in a plate 103 secured to the top of the intermediate frame member. The arms 94, 95 have similar thread-guiding slots 97, and are arranged alternately with overhanging fixed arms 104 having thread eyes 105 through which and through the slots 97 the under threads pass. The needle threads pass through guiding-eyes 112 in a post secured at one side of the slot 102, the guiding- slot 100 in the arm 96, under a hook-shaped guide 109 secured on the other side of the slot 102, and through a guide 99 in a tail piece 98 formed on the intermediate arm 95. The threads are led from the usual tension devices through guides 116 to the take-up devices. The needle threads pass through guides 130, 131 on the needle lever to the needles. Between the take-up device and the guide 116, a nipper comprising two superposed spring plates is provided for the under-threads. The plates are normally apart and are brought together to nip the threads by a cam on the main shaft. The under-threads are led from the takeup device to a tube passing through the cavity 5. then under a thread wheel, and guide-hook carried by a plate secured in a recess in the side of the work arm and through a guide at the end of the work arm to the loopers.