GB597767A - Thread controlling means for sewing machines - Google Patents

Abstract

597,767. Sewing machines. FAIRWEATHER, W. C. (Singer Manufacturing Co.). Aug. 25, 1945, No. 21881. [Class 112] Intermittent tensioning-devices.-A device for applying heavy tension to the thread during stitch-setting in machines for sewing heavy or hard materials comprises a pair of thread-engaging members to which pressure is applied through a yielding thrust member by a reciprocating member; means are provided for adjusting the tension and also for varying the duration of application of the tension. In the arrangement shown, the tension discs 31, between which pass both threads of a two-needle machine, are mounted on a plunger 23 slidable in a bushing 15 secured in the frame of the machine by a plate 18 ; the plunger is reciprocated by an eccentric 13 on the needle bar shaft 6. The threads pass to and from the discs through slits such as 22 in lugs standing up from the plate 18. The outer disc 31 is engaged by the rim of a cap 38 adjustably carried on a rod 35 which is housed in a bore of the plunger 23 and acted on by a compression spring 40; the inner disc bears against a collar 26 adjustably fixed on one end of the bushing 15. Adjustment of the tension is effected by adjusting the nuts holding the cap 38 on the rod 35, and the duration of tension, which also determines the instant in the stitch-forming cycle at which tension is applied, depends on the lost motion between the discs 31 (which are normally separated by reason of the cap 38 bearing on the end of the plunger) and thus on the position of the collar 26. Specification 565,581 is referred to.