GB662061A - Improvements in or relating to double lock stitch leather sewing machines - Google Patents

Abstract

662,061. Sewing-machines. WINTERHOFF, W. Feb. 11, 1949 [Feb. 11, 1948], No. 3762/49. Class 112. Presser-bars, lifting and locking. - In a leather-sewing machine with a spring-pressed presser-foot lever locked during stitch-forming and with a presser-raising linkage coupled to the presser-foot by disengageable teeth, the mechanism includes a cam-actuated member with locking teeth and a lever, connected to the former lever, controlled by a stop and acting on a pawl on the presser-foot lever. In the arrangement shown, the three-armed lever 8 carrying the presser-foot 9 is connected to a sliding locking- bar 18 with staggered teeth engaged by a pair of detents 28 actuated by a cam 32, and is biased by a strong tension spring attached to its lower end to press the foot 9 against the work; the member 39, slidably pivoted at 38 and actuated by a cam 54 against the action of an adjustable spring 58, is connected to the lever 8 by a slot engaging a pin 45, and has at its end a set of teeth 42 for engagement by a spring- pressed detent 43 which can be lifted by a release lever 36 pivoted on the lever 8. The lever 36 has a finger 50 for engagement by a roller on one arm of a lever 46 pivoted to the member 39 and arranged to engage an adjustable stop 48; thelever 46 and a tail on the lever 36 are connected by a tension spring 52. The cam 32 releases the locking detents 28 while the needle and awl are clear of the work, so that the presser-foot can be lifted by means of a handle 35 on the lever 8 when the machine is stopped in this position, the pawl 43 being released by the lever 36; it also releases the detents 28 while the member 39 is being operated by the cam 54 to lift the presserfoot, the pawl 43 being released by the lever 46 during the return of the member 39 to allow the presser-foot to accommodate itself to the thickness of the work so that it is always lifted by the same amount. Work supports and guides.-The slotted worksupport 10, fixed to a projection 11 on the machine frame, carries a pivoted back gauge 14- adjusted by a screw 15 threaded into the shank of the support.