Patent GB-481718-A (GB)
Title: Improvements in or relating to sewing machines
IPC: H02J3/46
Filed: 1937-08-27
Abstract: 481,718. Sewing - machines. MASCHINENWERKE ZU FRANKFURT AM MAIN VORM. KOLB, RIEBER, & CO., GES. Aug. 27, 1937, Nos. 23574 and 23575. Convention dates, Nov. 24,1936 and June 11, 1937. [Class 112] A machine whose main use is to sew decorations on to shoes has an oscillating needle bar 7, and means to move the bar axially of the driving spindle 3, and also transversely, so that groups of stitches may be formed at the corners of a square, or other polygon. A rotary looper 35 is driven through bevel gearing 24a, 28, a spindle 26 having two universal joints, and bevel gearing 31, 34. A needle plate 33 is fitted on the carrier 36, and accompanies the movements of the needle rod bearing, and is fitted close under a stationary work-supporting table 49, which forms the front end of a bracket arm 41. The latter may be adjusted in different fixed positions. A double-armed lever 39 bears on the bracket arm at 38, and carries a funnel 40 to hold the work, and also act as a fingerguard. At the rear end of the arm 39, a chain connected with a treadle is attached. A tension spring 50 keeps the funnel 40 pressing down on the work until the treadle is pressed downwards. With the work in position, a second treadle is pressed down to lower a rod 46, which draws a wedge 17 downward to press a sleeve 17a against the bearing 18 and cause a friction disc 19 to clutch a rotating pulley 20. The movement of the rod 46 frees a brake 21 from engagement with the disc 19. The disc 19, bush 4, and spindle 3 now rotate. A spindle 23 has affixed to it a cam piece 12, gear wheels 24, 25, and a bevel wheel 24a. A clamping piece 9 (and the head 2) is given axial movement by means of a roller 10 in a groove 11 on the cam 12, and a further clamp 13 imparts an oscillating movement to the head through a roller 14 which runs in a groove 11<1> on the surface of the cam 12. A toothed wheel 16 is loosely rotatable on the bush 4, and drives the spindle 3 through gears 16, 25 (with ratio 2 : 1) and 24, 24b, (with ratio 4 : 1) so that with one revolution of the gear 16, the spindle 3 revolves eight times. The spindle 3 rotates through the key 47 with the bush 4 forming the hub of the gear wheel 24b, but the key permits axial movement. Upon releasing the second treadle and the rod 46, a roller 22 rests on the rim of the gear 16 until it has made one revolution, when the roller drops into a notch on the pulley and the wedge 17 and brake 21 are respectively disengaged, and engaged, to stop the disc 19. Thus with a single rotation of the spindle 23 the needle carries out four stitches which are located at the corners of a square. The needle rod axis takes up four positions which are located on a wedge-like surface with the apex directed upwards. The cams cause the needle rod movements to occur during pauses in the stitching The looper, Fig 7, is so constructed that it draws the loop formed through the previously produced loop. The looper 35 has an aperture 35<1> so that the needle can penetrate into it. In a modified form the looper has a loop forming part which is hollow to allow more clearance between the needle and the looper in case the needle point is deflected. The gear ratios of the toothed wheels may be varied, and the needle rod bearing movement may be carried out other than by means of cams. The first treadle movement may be made automatically by means controlled by the driving pulley. The rod 46 may also be connected with the lever 39 to automatically raise and lower the funnel 40. The machine may be used for sewing on perforated buttons, or where two or three articles are temporarily attached together as in dyeing.