GB163221A - Improvements in and relating to buttonhole sewing machines - Google Patents

Abstract

163,221. Imrie, H., (Reece Button Hole Machine Co.). June 17, 1920. Button-hole sewing-machines. - A latch which holds the work-clamp closed on the work while the main feed-cam moves it from button-hole cutting position to stitching position and during the stitching operation is tripped to unclamp the work, when the stitching operation has been completed, by a cam device rigid with the main cam. Blocks 7 carrying the work-clamping feet 3 are loosely mounted on a rock-shaft 5, Fig. 3, and are rocked about the shaft to clamp the work by an arm 6 on the shaft which engages an arm 8 projecting from one of the blocks 7 which has a lip 9 overlying the other block. On starting the machine, the main feed-cam actuates a lever which, through the link 20 and pin 21, swings the arm 22 on a rock-shaft 11 to press a cam lug 12 thereon into contact with the arm 6, thereby closing the clamp. A latch 13 pulled down by the spring 14 drops behind the arm 6 to hold the clamp closed until the stitching is completed, whereupon the latch is tripped to allow the clamp to release the work by a cam 27 carried on the hub 28 of the main feed-cam. The cam 27 engages a roller 30 on a lever 31 and swings this lever to raise, through the link 34, the lever 24 which carries an arm whose end 26 underlies the latch 13, thereby tripping the latch and unclamping the work. The cam 27 may be so positioned with respect to the main feed-cam that the latch 13 is tripped either before, during or after the work-clamp has been given its final movement from button-hole stitching to buttonhole cutting position.