Patent GB-784200-A (GB)
IPC: D05B3/02
Abstract: 784,200. Sewing machines. UNION SPECIAL MACHINE CO. Jan. 19, 1956 [Feb. 3, 1955], No. 1798/56. Class 112 [Also in Group XXIV] Needles, shifting laterally. The needle bar 18, Fig. 1, is mounted in one limb 22 of an L- shaped frame pivoted on .a stud 23, the other limb 24 of the frame extend-' ing through the arm 12 into the standard 11. The limb 24 is connected by a pitman 29, of variable length, with a rock frame 33 actuated from the driving shaft 14 through gears 46, 45. Lateral whipping of the limbs 24, 22 is prevented respectively by a guide 145 and surfaces on the needle-head. Instead of the L-shaped frame being formed by limbs secured together by rivets 25 as shown. it may be formed by a pair of parallel spaced L-shaped thin steel plates stiffened and united by a series of blocks copper welded therebetween, Figs. 17- 21 (not shown). The gear 45, Fig. 9, is of fibrous material and is mounted on the hub of a cam 37, with a dwell of 70 degrees, embraced by a fork on the frame 33. The lower end of the pitman 29 embraces a ball-headed pin 31 engaging a slot 32 in the frame. The amplitude of the needle vibrations may be varied by varying the position of the pin relative to the pivot 34 of the frame. Stitch forming. The driving shaft 14 is in sections interconnected by couplings 16, 17, and actuates a four-motion looper 56. In Figs. 13-16 (not shown), a loop retainer is carried by an eccentric strap embracing a cylindrical eccentric mounted on the driving shaft. The strap is reciprocated along its eccentric by a spherical eccentric adjacent the cylindrical one so that the retainer moves in an elliptical path. Feeding work; presser bars. In addition to a lower feed-dog the machine of Fig. 22 employs a puller roller 190 arranged above the work. A variable eccentric 163 is arranged on a shaft driven by gear 46, through an intermediate fibre gear 150. A pitman 166 operated by the eccentric drives the roller step-by-step through a one-way clutch (see Group XXIV), gears 176, 183, and a shaft 186 comprising universal joints 185, 187. The shaft bearing, at the puller roller end is capable of guided vertical movement against an adjustable spring 201. A block 202 on the presser bar has a downwardly extending arm 203 at the lower end of which a presser foot 204 is pivotally mounted. When the presser bar is lifted to introduce or remove work the block 202 engages a shoulder on member 205 secured to the puller roller bearing to raise the latter also. A bent wire element 207 surrounding the roller strips the work therefrom during feeding. A block secured to the presser bar is connected by a link with a lever 93, Fig. 1, mounted on a pivot screw 95 and provided with an :arm 94 connected by a rod 96 with a plate 97 secured to a rock shaft 98 carrying an arm connected by a chain or rod to a knee-press or treadle. Threads, controlling. An extension on the arm last referred to has an elongated camming slot co-operating with a screw stud projecting from an arm clamped on a transverse rock shaft carrying another arm provided with a pin acting on a further slotted plate, by camming action, to perform the tension releasing function on the thread tension devices, Fig. 3 (not shown)