GB438648A - Improvements in and relating to sewing machines - Google Patents

Abstract

438,648. Sewing-machines. HUGHES, R. M., 72, Cannon Street, London.-(International Button Hole Sewing Machine Co. ; 502, Harrison Avenue, Boston, U.S.A.) June 24, 1935, No. 18059. [Class 112] In a machine for sewing imitation or uncut buttonholes, the feeding means produce a relative movement between the stitchforming mechanism and workholding means after completing the sewing to break the thread and then produce a relative movement in the reverse direction to bring the parts back to starting position. In the form shown, the invention is shown as applied to a machine in which the work is held on a stationary frame 1 and the stitching mechanism is carried in a frame 5 movably mounted on the work frame. The stitch frame 5 has the usual arm 6, needle bar 7, and under portion 10, carrying the turret. 11 for the loopers. The stitch frame is moved to-and-fro by the usual cam 14. Figs. 2 and 3 show the parts in the position they take when the machine is brought to rest before starting, the needle being in position a and the follower 16 occupying the position in the cam groove 17 shown in full lines in Fig. 3. The stitch frame 5 is at its rearmost position. The cam 14 rotates in a clockwise direction, Fig. 3, when the machine is started and the wheel 25 is clutched to the shaft 23 to give the cam its initial high speed movement. The cam shifts the frame 5 forwards to bring the needle to position b from which the stitching starts. During this interval the cam 14 has turned to bring the follower 16 from a<1> to b<1>. As the cam 14 continues its rotation, the follower 16 travels from bl to c<1>, moving the stitch frame to bring the needle to the position c, during which time the stitches 70, Fig. 4, are made along one side of the buttonhole. At position c, the turret and stitch-forming mechanism are turned to sew round the end 76 of the buttonhole. Further continued movement of the cam 14 causes the follower 16 to travel from c<1> to b<2>, giving the stitch frame 5 a reverse movement to bring the needle from c to b to make the stitches 71. When the cam has turned so that the follower 16 has travelled to the point b<2>, the needle is back at b and the stitch mechanism is brought to rest. The clutch wheel 25 is again coupled to the shaft 23 to produce a rapid rotation of the cam 14 for the remainder of the machine cycle. During further rotation of the cam 14, the follower 16 travels from b<3> to d<1>, giving the stitch frame a second forward movement to carry the needle from b to d and break the upper thread at the last stitch. As the cam 14 completes its rotation, the follower moves from d<1> to the starting point a<1>, bringing the needle from d, through b back to a. The wheel 25 is then disengaged from the shaft 23 and the parts are ready for the next cycle.