GB685896A - Machine used in the making of piped buttonholes - Google Patents

Abstract

685,896. Sewing-machines. FISCHBEIN, D. March 21, 1951 [Oct. 16, 1950], No. 6749/51. Class 112. A two-needle machine for use in making piped buttonholes has a slitting blade between the needles actuated by means which can be put into and out of action at will during operation, so that the slit made can be shorter than the lines of stitching. A device for folding a tape to a #-section with all limbs double is attached to the presser-foot, which is modified to guide the tape so folded. Folding devices.-A flat tape 50, Fig. 4, to form the piping of a buttonhole, is fed into a flared part 51 of a folding device attached to the presser-foot of the sewing-machine, the wings of the device being shaped so that the tape is folded around a central #-section member 52 supported by a bridge 53. Presser-feet.-The foot 22, Fig. 6, is formed to guide the tape in its folded form so that the two needles 17 can stitch it through its " flanges " to the work over the position of the required buttonhole. Cutting.-A thin blade 16 carried by a vertically-reciprocating rod 24 works between the upstanding limbs of the tape to cut the base portion of the tape and the work beneath it to form the buttonhole slit. The rod 24 is actuated by a crank 30 on a rockshaft 28 which is oscillated by a cam 18 on the needle-bar or similar shaft 19 through a follower 20, pivotally connected to a crank 29 on the shaft 28 and spring-pressed against the cam, so that the blade 16 makes a cutting stroke for each descent of the needles; the width of the blade is such that successive strokes make a continuous slit in the work. In order that the operation of the knife may be suspended during the first and last parts of the sewing operation, so that the lines of stitching extend beyond both ends of the slit, a hand-operated spindle 43, mounted transversely on the arm of the machine, carries an arm 44 which can move in front of a boss 31 on the cam follower 20 to hold the latter in its rearmost position so that it cannot follow the cam 18, the blade 16 being then at the upper end of its travel; the arm 44 is held in its obstructing position by friction with the boss 31 under the pressure of the spring acting on the follower, against the pull of a weak return spring 45; the free position of the arm 44 is determined by a stop 48, on an arm on the spindle 43, engaging the machine arm.