GB695820A - Improvements in and relating to machines for joining together lengths of cloth - Google Patents

Abstract

695,820. Sewing-machines. HARRAP, Ltd., N. W., and JOHNSON, J. S. Nov. 23, 1951 [Nov. 25, 1950], No. 28878/50. Class 112. A butt seam is produced by stitching together two superposed work-pieces in an overedge sewing-machine, the stitches being formed round a projection on the work-plate or presser-foot or both so that they are loose enough to allow the work-pieces to lie flat when opened out. Loop-stitching; loose stitches, producing.- The needle 17, Fig. 4, is carried by an arm 16 freely mounted on a shaft 15 perpendicular to the line of feed and oscillated by an eccentric 18, Fig. 1, on the main shaft 13. The under looper 43 is carried by a shaft 44 and is oscillated by another eccentric on the shaft 13, while the overedge looper 42 is mounted on a shaft 49 and oscillated by an eccentric 51 on a shaft 34 geared to the main shaft 13 to run at the same speed; the shafts 44, 49 are slightly inclined to the line of feed on opposite sides thereof so that the loopers pass on opposite sides of the needles. The stitches are tightened round a projection 60, Fig. 4, on the presser-foot 53 so that on removal of the work they are slack enough to allow the seam to be opened out flat; as an alternative to the projection 60, a projection on the work-plate may serve a similar function. Feed by dogs.-The feed-dog 23, Fig. 1, is fixed to a plate 22 which is slidable longitudinally in a carriage 30 pivotally mounted at the rear end on the shaft 15 by arms 31 and supported at the front end by a pitman from an eccentric 33 on the shaft 34, whence it receives a rising and falling movement; the feed movement of the dog is derived from the shaft 13 by means of an eccentric 21 with adjustable connection to an arm 27 of a member 26 rocking on the shaft 15 and connected by a link 24 to the plate 22. Trimming.-The edges of the work-pieces are trimmed, before being sewn, by a vertical blade 38, carried by an arm 40 on the rising and falling feed carriage 30, co-operating with a stationary blade 39 carried by a. spring-loaded spindle 41 which presses the blades together; the blades are slightly inclined to one another both in plan and in elevation, giving a shearing and hollow-ground effect. The cutting takes place as the feed-dog descends after feeding the work. Presser-feet; presser-bars.-The presser-foot 53, Fig. 4, has an upturned front edge with a lateral extension 54, and is mounted on an upright member 55 pivoted to the presser-arm 57, which is pivotally mounted on a bracket 58 and is pressed downwards by a spring 59.