GB774268A - Work-jogging attachment for sewing machines - Google Patents

Abstract

774,268. Sewing machines. SINGER MANUFACTURING CO. Sept. 29, 1955 [Oct. 8, 1954], No. 27708/55. Class 112. The pattern cam of a work jogging attachment for a sewing machine is bodily movable into and out of operative engagement with the mechanism for turning it and the workshifting member. The frame of the attachment comprises a base plate 10 with upstanding ears 11 between which is secured a block 13 slotted at 14 to accommodate the ends of the presser bar 15 to which the block is secured by a screw 16. The screw has a necked portion 18 loosely confined in a slot in a finger 20 on one of the ears 11. The shank 30 of a workfeeding foot 28 has a slot 31 engaging a fulcrum pin 32 on a slide plate 33 provided with a second pin 34 engaging a slot 35 in the base plate 10. A flange 36 on the slide plate is formed with a finger grip 37 by which it can be moved to vary the position of the fulcrum pin and hence the bight of the stitches. The slide plate may be locked in the adjusted position by a clamping screw 39 threaded into an ear 11 and engaged by a slot in the flange 36. Rearwardly of the slot 31 the shank 30 is offset upwardly and provided with a camfollower pin fitted with a roller 41. The shouldered base of the pin is disposed in a transverse slot 42 in an arched bracket 43 secured by screws to the baseplate 10. A ratchet wheel 54 mounted for rotation on a stud 57 secured to the baseplate, has an upstanding hub comprising portions 55, 56 of different diameter. The removable pattern cam 58 has an internal cam surface 64 and a tapered bore engaging the hub and making ring contact with both portions thereof. Diametral lugs on the bore engage notches 62 in the hub, and a hinged lid 71 of a cover 65 for the attachment frame carries spring members 74 which include parts 77 adapted to bear on the cylindrical portion of the cam when the lid is in the closed position and parts 76 adapted to engage the cover to retain the lid so closed. The cover 65 is secured to the block 13 and the baseplate 10 by screws 67, 69. The ratchet wheel is driven step-by-step from the needle-bar by means of a lever 22 carried by a pin 23 journalled in the ears 11. One arm of the lever is forked to embrace a cylindrical portion 24 of the needle clamp 25, and the other arm 45 carries an out-turned lug 46 embraced by fingers 47 of a slide plate 48 confined to longitudinal movement on the baseplate 10 by pins 49 on the plate 10 engaging slots in the plate 48. A spring-loaded pawl 52 pivoted at 51 on the plate 48 engages the teeth on the ratchet wheel. Straight-line stitching may be produced without removing the attachment by means of a lever 83 pivoted at 84 to the slide plate 48 and underlying a projection 85 on the pawl provided with a T-slot 87 engaged by a pin 86 on the lever. In the " throw out" position of the lever shown in dotted lines the pin enters the portion 88 of the T-slot and disengages the pawl. The plate 48 then reciprocates idly.