| 摘要 |
1309408 Differential feed mechanisms UNION SPECIAL MACHINE CO 22 May 1970 [26 May 1969] 24855/70 Heading D1G Two side-by-side differential feed bars 37, 38 with feed dogs 35, 36 of an over-edge or other sewing machine are relatively slidable longitudinally, by virtue of a tapered block 51 secured to the feed bar 37 and engaging a slot 38d in the feed bar 38, and are reciprocated by independent adjustable mechanisms from respective eccentrics 55, 56 on a main drive shaft 30 through pitmans 60, 102, the mechanisms being adjustable independently to adjust the strokes of the two feed bars. The forked rear ends 37a, 38a of the feed bars are slidable on a block 39 mounted on an eccentric pin 41a by which the rear height of the feed bars may be adjusted and vertical movement of the front ends of the feed bars is controlled by a block 45 mounted on a further eccentric 30a of the drive shaft 30 and engaging a fork 37b of the feed bar 37. The feed bar 37 is reciprocated by the pitman 60 through a slotted rocker 64 journalled on a shaft 70, a slidable block 72 and a link 74 and its stroke is adjusted by rotating the head 120a of a threaded rod 120 which abuts a lug 78d on a crank 78 with an arm connected by a link 77 to the slidable block 72. An indicator arm 87 is rotatable with the crank 78 and abuts a scale 85 to show the length of feed. The feed bar 38 is reciprocated by the pitman 102, through a pin 103, which is selectively mounted in holes 105 or 106 of an arm 104 secured to the shaft 70, the shaft 70, a slotted rocker 101 secured to the shaft 70, a slidable block 100 and a link 110. The block 100 is movable, to adjust the feed, through a link 98 and an arm 91 secured to a shaft 80 which is rotatable by a bellcrank lever 86, one arm 86b of which is movable during sewing by for example a treadle or knee press connected thereto. The other arm 86a has a pointer abutting the scale 85 and is movable between two adjustable stops 131a and 132 which set a minimum and a maximum stroke or it may be held in place by a screw 142. The stops are adjustable by rotation of a knurled disc 135 and a head 130a. |
