GB487174A - Improvements in sewing machines - Google Patents

Abstract

487,174. Sewing-machines. MACHINES PTY., Ltd. May 25, 1937, No. 14467. Convention date, June 8, 1936. [Class 112] The invention consists in a simplified shuttle - operated lockstitching machine. Thread from a reel on the spindle 9 is passed through a slot in the plate 4, round the tension device 35, through the take-up arm 33, and through the eye of the needle 20. The thread of the bobbin in the shuttle 39 passes along the slot 50 beneath the spring 40 and back into the slot 51 of the spring. The shuttle 39 is then placed in the carrier 38 so that its point is outside the open end of the carrier with flanges 45 straddling the race 37, the spring 46 forcing the shuttle against the race. The presser foot 25 is raised by the lever 28, the end of which slides along the top of the extension 27, and the pin 31, which secures the lever to the presser bar 26, sliding in the slot 31b. This also raises the feeder bar 23 carrying the feeder foot 23a. The cloth is then placed on the throat plate, the needle being in raised position, and the presser foot and feed foot depressed. The fly wheel 7 is thus rotated, turning the shaft 5 which has a crank 14 carrying a pin 13 working in an open cylinder 12a carried by the two-armed lever 10, one arm of which operates the needle, presser and feed bars, and the other the shuttle. The flywheel may be rotated in either direction. As the needle bar 15 descends, the roller 18 moves along the straight edge 52 of the cam 21 and the feed bar 23 remains stationary. When the roller 18 leaves the straight edge 52 and coacts with the curved edge 53, the presser bar 25 is lowered slightly to press hard on the cloth. In this position, the pin 31 becomes the fulcrum of the cam 21 and further downward pull by the spring 29 tends to raise the L-portion of the cam 21 so withdrawing the extension 24 from the face of the feeder bar 23. The spring 54 then pulls the feed foot 23a to the right. On the reverse movement, when the needle rises, the roller 18 moves upwards along the curved face 53 of the cam 21, first depressing the foot 23a on to the cloth, then raising the presser foot and causing an extension 24 of the cam 21 to push on the upper part of the feed bar 23 to cause the foot to move the cloth to the left. The feed stroke is governed by the position of the cone-pointed screw 32 relative to the feed bar 23. The lever 10 drives the shuttle 39 in unison with the needle by the link 47 in the way usual for making lock-stitches. The shaft 5 is retained in position by a screw 5b engaging an annular recess 5a.