GB141262A - Differential feeding mechanism - Google Patents

Abstract

141,262. Fairweather, W., (Singer Manufacturing Co.). Aug. 8, 1919. Sewing-machines ; feed by dogs.-In a differential feeding mechanism, as described in Specification 129,897, both feed-dogs are pivotally connected to the same rock frame, but the rising and falling movement of one is, imparted to it by the other through a differentiator which causes the feed-dog to withdraw from the work before the feeding stroke is completed. The time at which this withdrawal takes place is determined by the adjustment of the differentiator. The invention consists in providing means by which it can be altered during the running of the machine. The feed-bar 11 carrying the feed-dog 5 receives an unalterable rising-and-falling movement. Pivoted at 34 upon this feed-bar is a lever 36 anchored by a link 37 to a fixed bracket 38 and having a transverse slot 39 in which slides a block 40 pivoted upon a pin 41 adjustably carried by a feed-bar 31 which carries the feed-dog 29. When the pin 41 and the pivot 34 are co-axial, the feed dogs operate together. When by the movement of a, manually-controlled lever 48 the slide 43, carrying the pin 41, is moved and the pin 41 is no longer co-axial with the pivot 34, the forward movement of the feed-bar 11 will cause the lever 36 to tilt, carrying the pin 41 upward or downward, in accordance with its position in relation to the pivot 34, and thereby the effective stroke of the feed-dog 29 is prolonged or shortened and the material stretched or crowded. Presser feet.-The presser-foot, Fig. 1, comprises a shoe 54 pivoted at 56 to a bar 57 pivoted at 58 to the rear portion 55. A spring 59 presses upon the bar 57.