Patent GB-468032-A (GB)
Title: Improvements in or relating to sewing machines
IPC: D05B1/20
Filed: 1935-10-23
Abstract: 468,032. Sewing - machines. WILLCOX & GIBBS SEWING MACHINE CO. Oct. 23, 1935, No. 5221/37. Convention date, March 16, 1935. Divided out of 464,773. [Class 112] In an overedge sewing-machine of the kind described in Specification 464,773, a take-up member is associated with the means for guiding the needle and looper threads to act directly on the needle and looper threads. The invention also includes means for facilitating threading the loopers. The thread-control mechanism is indicated generally in Fig. 1 by the reference 78 ; all the threads pass in one direction and only one take-up finger 324 operates on all three threads, one needle thread and two looper threads. Adjacent to the workplate 60 is a battery of thread-tensioning devices 316, 325 and 330 for the lower looper thread 313, overedge looper thread 314 and needle thread 310, Figs. 2 and 11. Each of these devices includes a pin carrying, a pair of tension discs maintained in yielding engagement by springs 345. Adjusting nuts enable the variations to be applied to the tensions of the looper threads. In the case of the needle thread tension device a loose plate 340 carries pins 341 which can be entered into slots in the nut 343 so that the tension on the needle thread can be rapidly adjusted to two valves by depressing and turning the plate 340, or by entering the pins to the slots, to produce different types of stitches. The light tension is required for stitches such as shown in Fig. 24 and the heavier tension for stitches such as shown in Fig. 25. Near the tensioning devices is a nipper or thread holder 318 comprising a lower stationary plate secured to the top housing 126 and a spring finger moving into and out of clamping position in timed relation with the stitching mechanism by an operative connection to the shaft 147 of the trimming mechanism 77. The thread guiding element of the take-up device comprises U- shaped guide plates 319, 331, 327 secured to the top housing 126 by a screw 320 and nut 3201. Each plate has eyelets to receive the respective threads as they pass from the three tensioning devices. A single finger 324 is provided on the top of a crank arm on the main drive shaft and passes through an aperture 324<1> in the work plate 60 to oscillate and reciprocate between the U-shaped guide plates 319, 331, 327 once each time the needle 120 and loopers 289, 299 are actuated, to take up the slack thread as the needle and loopers move towards a retracted position. The guide plate may be shifted collectively or individually to enable a wide range of adjustment for thread conditioning. The overedge looper thread 314 passes from the tension device 325 through a guide tube 326, through the eyelets of the U-plate 327, through a second tube 328, and through eyes 329 to the overedge looper 299. The lower looper thread is guided by eyelets 317 on the fixed plate of the thread nipper and passes from the U-plate through a hole 332 in the plate 60 to a slot 335 and guide 334 in a slide 336 to the eye 337 of the lower looper. Threading sights and guides 337a and 329b are provided for facilitating threading of the loopers. Suitable threadguiding grooves are associated with these sights.