GB510072A - Improvements in or relating to feeding mechanism for sewing machines - Google Patents

Abstract

510,072. Sewing-machines. MERROW MACHINE CO. Jan. 21, 1939, No. 2170. Convention date, Jan. 22, 1938. [Class 112] In order to guide the work automatically to produce a straight seam, a sewing-machine is provided with a device adapted to engage the work in advance of the feed mechanism and to be moved against a resistance so that the work is kept under tension. The invention is shown applied to an overedge sewing-machine for connecting the edges of two superposed pieces of fabric which are afterwards opened out to lie flat edge-to-edge ; the machine has a curved needle 2, trimming knife 6, feed dog 4, presser-foot 3, needle-plate 5 and work-table 11. The righthand end of the table is shown broken off and placed beneath the remainder. A member 21, running on rails 25 and projecting through a slot in the table surface 11 in line with the stitching point, has pivoted to it a plate 28 carrying pins 29 on which the rear end of the work is impaled so that as the work is fed past the needle in the usual manner it pulls the member 21 along against the resistance provided by a weight 30 on the end of a chain 31 attached to the member 21 ; the work is thus kept taut and straight in its passage up to the needle. The pins 29 are automatically retracted from the work when the member 21 is near the needle by engagement with a bracket 35 on the end of the rails 25, the member 21 being then moved back by the weight 30 to a position for attachment to a new piece of work ; this return movement is limited by a stop 37, adjustable on the table 11 to suit the length of the work, engaging a spring buffer 39 on the member 21. The member 21 may carry a cam device adapted to engage a switch lever 40 during the return movement to stop the machine automatically on completion of a seam. The usual feed of the machine is supplemented by a spiked endless chain 53 projecting through the table surface 11 to engage the work at one side of the feed-dog 4 in a line parallel to the seam and the rails 25, the work being stripped from this chain by plates 79 ; the chain is driven by a motor 60 by means of a sprocket chain 63 and gearing 70, the chain 63 also serving to drive the sewing-machine mainshaft 8, so that the chain 53 is synchronized with the machine feed. A guard may be attached to the stop 37 to cover the spikes of the chain 53 in the neighbourhood of the pins 29 to prevent injury to the operator when impaling the work on the pins. U.S.A. Specifications 733,760 and 1,943,243 are referred to.