Patent GB-190107326-A (GB)
Title: Improvements in or in connection with Sewing Machines.
Inventor: PARKES WILLIAM NELSON
Filed: 1901-04-09
Granted: 1901-08-17
Abstract: 7326. Parkes, W. M. April 9. Ornamental-sewing machines; needle-bars, vibrating laterally; feed; overedge - stitching machines; embroidery.-Relates to mechanism, such as shown in Fig. 2, for varying the lateral vibration of the needle-bar, and the extent and direction of the feed, in order to produce either plain, overedge, or ornamental sewing. The mechanism comprises the cam lever G, which vibrates the needle-bar through a lever K pivoted on an elbow lever H, the extent and position of the needle-bar's vibrations being varied by slotted levers M, h<2> respectively, operated by a slide L reciprocated by a cam on the ratchet-wheel O. A. second ratchetwheel P is formed with a cam, which, through an elbow lever and link r<8>, Figs. 2<a> and 13, controls the position of the feed-regulating shaft r, which is also capable of more or less non-central adjustment by means of the slot r<7> and scale r<1>. The ratchet-wheels are rotated by pawls n', p<5> operated from a cam lever S. The invention consists of means for automatically placing the ratchet-wheels O, P into a predetermined angular relation, means to cause the cams on the ratchet-wheels to be brought to their extreme or other predetermined positions at the termination of a stroke of their respective pawls, and, lastly, of certain constructional details. The ratchet-wheel O has gaps o<13>, Fig. 6, which can be wholly or partially closed by the teeth of a similar, mutilated, ratchet-wheel W, Figs. 2 and 3, adjustably connected to the wheel O. Thus, by opening the gaps O<13> to the extent of one tooth less than the feed of the pawl, the next stroke of the pawl after passing a gap always begins on the first tooth after that gap. The wheel P has a similar adjustable gap. The connection between the ratchet-wheels Wand 0 is by means of a pin w<16> adjustable in a slot w<6> in the wheel O, the head of this pin engaging a slot w<7> in the wheel W, the length of which slot can be adjusted so as to allow a relative movement between the two wheels of either one or two teeth, or no movement at all. The wheel W carries a segment w<3>, and a pawl w<5>, acting only on the teeth of this segment, can be fed the extent of one tooth by the engagement with a pin w<18> on the pawl lever, of a cam p<17> adjustable on the wheel P by means of a screw and slot p<16>. Supposing the slot w<7> is adjusted so that a relative movement of one tooth between the wheels W and O is allowed, and that the gaps O<13> are adjusted so that, when opened as widely as the slot w<7> will allow, they correspond in length to the number of teeth being fed by the pawl n<7>, then this pawl on reaching one of the gaps O<13> will continue to oscillate there until the cam p'7 in the course of the rotation of the wheel P causes the pawl w<5> to feed on the wheel W one tooth, so that the pawl n<7> can again come into action. Instead of one cam p<17> there may be two, diametrically opposite. A friction controlling-device for the ratchet-wheel W comprises a friction strap y encircling a drum on the wheel, and bearing against the free end y<9>, Fig. 11, of a spiral spring secured to, and retained by, a nut y' on the fixed spindle. A similar friction device is fitted to the wheel P. The corresponding fitting for the wheel 0 consists of a clip O<7>, O<8> sliding under the control of a spring and embracing a disc O<5> connected to the wheel O. The slotted arm g<5>, from which the needle-bar is vibrated laterally, is pivoted on the sleeve g, Fig. 15, of the lever G and on the same axis as this lever, and its lower end is adjustable on the lever G by a screw and slot, so that the increase and decrease of the lateral vibrations of the needle-bar may be set to be made more or less to one or the other side of a centre line.