GB612696A - Improvements in sewing machines with a free work-arm - Google Patents

Abstract

612,696. Sewing-machines. KELLER, J. May 30, 1946, No. 16508. Convention date, June 7, 1945. [Class 112] The free work-arm of a sewing-machine is made invertible and arranged to present a flat upper surface in one position, for ordinary sewing, and a rounded surface in the other position, for darning. Means are provided to ensure that the feed mechanism is inoperative in the latter position. Frames.-In the arrangement shown, the standard 2 of the machine has welded or otherwise fixed to it a circular spider 3 which supports the tubular work-arm 7 and the mechanism therein. The lower half of the work-arm, in the position shown, is of rectangular cross-section and is provided with feed-dog and needle apertures, and the upper half is semi-cylindrical and has a needle hole only. The end of the arm is rounded and is provided with an inspection cover 7<1>. The arm is secured to rings 5, 6, of suitable form, rotatably mounted on the spider 3, and is held in either of its working positions by a pivoted detent 11 entering one of two notches in the ring 5. Feed regulating.-A detent 16 connected to the feed-adjusting mechanism is freely slidable through a notch in the ring 5 when the flat surface of the work-arm is in use, but when the rounded surface of the arm is uppermost this detent is locked in the position corresponding to zero or minimum stitch-length. A second sliding detent 20, connected to a hand-actuated lever 20a which shifts a block 24 on the feed-lift rock-shaft 25 into or out of engagement with its operating mechanism, is blocked when the flat surface of the work-arm is not in its position of use to ensure that the feed dog is dropped.