GB906661A - Improvements in or relating to ornamental seam devices in sewing machines - Google Patents

Abstract

906,661. Sewing-machines. PFAFF A.G., G. M. March 19, 1959 [March 19, 1958], No. 9512/59. Class 112. In a zig-zag sewing-machine comprising a plurality of pattern cam discs on a common rotatable shaft, and corresponding cam followers independently pivoted on a spring-biased rocker arm which is operatively connected to the stitch - forming means, abutment fingers are provided selectively movable to an operative position in which the selected finger is fixed and engages the respective follower to hold the latter in contact with its cam, and the arrangement being such that consequent displacement of said follower and the resultant relative movement between said follower and the rocker arm causes displacement of the latter to influence the stitch-forming means. In Fig. 1 six pattern cams 7 are carried by a vertical rotary shaft 4. A rocker arm 9, pivoted at 12, is connected by a link 16 to the stitchwidth adjusting means. Individually pivoted at 14 on arm 9 are six followers 18, the noses 28 of which are adapted to co-operate with the respective cams. A rocker arm 10, pivoted at 13, is connected by a link 17 to the stitchposition adjusting means, and six followers 19 having cam-engaging noses 29, are pivoted at 15 on arm 10. A spindle 24 carries six fingers 20 arranged helically thereon and spaced radially at <1>/7th of 360 degrees apart. Spindle 24 is rotatable by a knurled wheel 26 to engage fingers 26 selectively with the tails of the followers 18, whereby any one of the noses 28 is engaged with its cam disc. Rotation of the latter displaces the nose and causes the tail to slide upon the finger 20, whereby displacement of the follower is transmitted to the rocker arm 9. A spindle 25, rotatable by a knurled wheel 27, similarly carries six fingers 21 which are selectively engageable with the followers 19. Spindle 24 is coupled by 1: 1 gearing 44, 47 to a shaft 36 which is journalled in a bracket 34 and fixedly carries a cylinder 39. Spindle 25 is coupled by 1:1 1 gearing 46, 48 to a shaft 37 aligned with shaft 36. Shaft 37 is journalled in a bracket 35 and in the cylinder 39, and fixedly carries a hollow transparent cylinder 42 concentric with and spaced from cylinder 39. The peripheral surface of the latter is formed with stitch-patterns, Fig. 3, corresponding to the combinations of the various cam followers and cams, and arranged in longitudinal lines b0 to b6 and transverse lines l0 to l6. The periphery of cylinder 42 is formed with diagonal markings 51, Fig. 4. Each movement of wheel 26 equal to <1>/7th of a revolution brings a succeeding longitudinal row b under a window formed in a cover enclosing the mechanism. Each movement of wheel 27 equal to <1>/7th of 360 degrees, brings a succeeding marking 51 under said window. The pattern under the latter which is covered by the marking 51 is the pattern selected. In a modification, Figs. 5 and 8, rocker arms 309, 311, pivoted at 312, 313, respectively, and connected at 314, 315 to links 316, 317 controlling the stitch-width and stitch-position, respectively, are disposed on either side of six rotary pattern cams 307. Individually pivoted at 314, 315 on arms 309, 311 are six cam followers 318, 319 having cam-engaging noses 328, 329. Slidably mounted in a cover 350, in opposition to respective springs 374, are seven fingers 322, each of which is formed with a lug 326 projecting through aligned apertures 376 in cover 350. Each finger 322 is formed with a tooth 368 adapted to co-operate with a pivoted pawl 370 which is biased by a spring 372 and is common to all said fingers. The arrangement is such that if any one of the fingers is moved inwardly by its lug 326, said finger is retained in the forward position by the pawl 370. Movement forward of any other finger releases the first finger and serves to retain the second finger in its forward position. Six of the fingers are formed with lugs 320 adapted, when the fingers are moved forward, to engage abutment surface 330 on the followers 318 to move the selected nose 328 into engagement with its associated cam. The seventh finger has no lug 320. Similarly, seven fingers 323, slidable inwardly against springs 375, are formed with teeth 369 adapted to co-operate with a pivoted pawl 371 biased by a spring 373 to hold the respective finger in the forward position. Fingers 323 are also formed with operating lugs 327 projecting through aligned apertures 377. The apertures 376 and 377 define adjacent sides of a parallelogram which is marked with corresponding lines of stitch-patterns, b0 to b6 and l0 to l6, any pattern of which is selected by moving inwardly the two knobs 326, 327 aligned therewith. In a further modification. Fig. 9, a rocker arm 409 is pivoted at 412 and is connected at 414 to a link 416 controlling the stitch width or position. Six follower members 418, also pivoted at 414, have noses 428 adapted respectively to cooperate with six rotary pattern cams 407. A spring 478 biases arm 409 away from the cams. Six abutment fingers 420 are mounted helically on a rotatable hub 422 to coact respectively with the members 418, and are spaced angularly at <1>/7th of 360 degrees apart. Specifications 906,662 and 906,663 are referred to.