Patent GB-687812-A (GB)
Title: Improvements in needle feed sewing machines
IPC: D05B57/02
Filed: 1951-03-06
Abstract: 687,812. Sewing-machines. UNION SPECIAL MACHINE CO. March 6,1951 [March 7, 1950], No. 5381/51. Class 112. In a needle-feed machine with a four-motion feed member in the base and a four-motion looper having its loop-seizing movement in a direction across the line of feed and a rocking movement in the line of feed, the latter movement is imparted by a connection from a feed rocker forming part of the connections between a rotary shaft, which also gives the looper its main movement, and the feed member. Needles, driving; feed by needle and by dog.- The needle-bar 16, Fig. 1, is mounted in a gate 17 pivoted on a stud 18, and is prevented from rotating by a, pin 54, on a block 53 on the needle-bar, engaging a slot 55 in the gate. The needle-bar is reciprocated by connections from the main shaft 14, including a pitman 42, lever 46, and link 51. connected to the block 53. The gate 17 is oscillated in the line of feed by connections from the shaft 14 including a pitman 37 adjustably connected to an arm on a rockshaft journalled in rearward extensions of the standard 11 and head 13. A feed-dog 93, Fig. 8, is vertically adjustable on a feed-bar 87 which is actuated by mechanism similar to that described in Specification 289,731., [Class 112], comprising a feed-lift eccentric 92 on the shaft 14 and a feed-rocker 79 secured to a pivot shaft 81 and actuated by an adjustable crank or eccentric on the shaft 14 connected to an arm clamped on a pin 99 extending from the feed rocker 79. The feed-dog may have a needle-slot in it, or may have a narrower rear part lying to one side of the needle. Double-loop stitching.-A thread-carrying looper 56, Figs. 1 and 8, is secured to a carrier 57 pivoted on a bolt 60 carried by a member 61 fixed to a rockshaft 62 which is oscillated, to produce the needle-avoiding movement of the looper, by a link 104 connected at alternative positions to the top of the feed-rocker 79 and connected adjustably to an arm 107 on the shaft 62, the arrangement being such that the looper has a greater movement than the feed-dog. The looper receives its loop-seizing movement from an eccentric on the shaft 14 actuating a crossshaft 71 having an arm 70 connected by a link 66 to the looper carrier 57. Multiple-needle machines. -In a similar machine for producing simultaneously two parallel lines of stitching, two needles are fixed to a cross-piece on the lower end of the needlebar and two loopers are provided. If the seams are to be close together the loopers are mounted on a single carrier and overlap, and the needles are correspondingly staggered; otherwise the needles are in line with the axis of the machine and the loopers have separated carriers with their pivot bolts 60 adjustable in horizontal slots in the member 61, one of the carriers being oscillated by the link 66 while, the other is limited to the first. Needle guards are provided on both sides of the needle. The front one 109, Fig. 8, is fixed to the looper carrier 57 and the rear one 119 is adjustably secured to the feed-bar 87. Both guards thus move with the needle in its feeding movement. Presser-bars.-The presser-bar 122, Fig. 1, is urged downwardly by a spring surrounding it between a collar fixed on it and an adjustable screw-threaded guide 124. The collar is connected by a link to one arm of a spring-biassed bell-crank 127 connected by a link 131 to an arm on a treadle-operated rock-shaft 133. Lubricating.-The pivotal connection between the feed-bar 87, Fig. 8, and feed-rocker 79 is lubricated by wicking, which may be supported by a metal member, surrounding the shaft 81 adjacent to a bearing thereof and extending into an axial bore in the pin 89. Other parts are lubricated by means as described in U.S.A. Specification 2,598,426. Frames.-The upper part of the frame is formed separately from the base and secured to it on a plane 10. A guard 15 is provided for the combined hand-wheel and pulley.