Patent GB-676117-A (GB)
Title: Special stitch sewing machine
IPC: D05B85/00
Filed: 1949-12-19
Abstract: 676,117. Sewing-machines. TRIGGS, W. W. (American Machine & Foundry Co.). Dec. 19, 1949, No. 32523/49. Class 112. Stitches; running-stitch machines.-In a machine with a double-pointed needle passed completely through the work, mechanism for producing stitches of the kind shown in Fig. 5 is provided, comprising a work-shifting element 52 which is moved periodically from a position in the plane of the work-table to a position inclined thereto. In the embodiment described, the element 52 is moved upwardly and to the left at alternate needle strokes to bend the work as shown so that alternate stitches lie at an angle to the faces of the work and the thread hardly shows. In the apparatus shown, the element'52' is pivoted to the upper end of a rocking arm 57, Fig. 1, and is guided at its right-hand end in a cam slot 60 in a plate 62, so that when a rod 68, connected to a cam-actuated lever 74, is pulled downwards the element 52 will be moved to the left as it is tilted upwards; the plate 62 is pivoted and spring-biassed to allow lost-motion at the end of the movement of the element 52 if required. The cam lever 74 may be moved clear of the cam to suspend the work-bending when required, by a rod 106 actuated by a treadle through a rod 125 and arms 114; it may be held out of action by a hook 209 engaged by hand over a fixed pin. A finger 296 on an arm actuated by a track in the periphery of a cam on the cam-shaft 205 moves the loose part of the thread aside between guides 270 and behind a finger 292 to keep it clear of the paths of the needle and the device which pulls the end through the work; the finger 292 is formed on a shelf which is provided to catch thread lint. Presser-feet.-The usual presser-foot 127, Figs. 1 and 5, has a forwardly-extending toe 131, forked to pass on either side of the needle, pivoted to it and spring-pressed downwards; this toe can thus be lifted by the element 52, which it overlies. Feed by dogs.-The usual feed-dog, co-operating with a feed-foot 121, Fig. 1, is carried by a bar 123 which is supported on an adjustable link 230 from a crank engaging a feed-lift arm 227 and receives its feed movements from an arm 220 moved laterally by a crank-pin on the shaft of the cam 227 engaging a slot in its lower end; its lateral movement is translated into a variable vertical movement (which produces the feed motion) by an angularly adjustable guide 136 engaged by a roller on the arm in the usual manner. During the normal operation of the. machine to produce the stitch described, or to produce alternate long and short stitches when the work-bending device is held out of action, the guide 136 is oscillated in time with the needle movements by mechanism described later. When the work-bending is only temporarily suspended, by means of the treadle, the guide 136 is held in a fixed position by an arm 128 connected to the treadle and engaging an arm 132 on the spindle 134 of the guide 136; the position of the arm 132 on the spindle is set when the machine is assembled, to hold the guide 136 in the position to give the required length of uniform stitch. The automatic production of long and short feed steps is obtained by connecting a cam-operated arm 188 to a crank 179 on the spindle 134 by a link 192 with a spring at each end to allow controlled lost motion in each direction, the crank-pin being extended to engage slots in the ends of two rods 252 which determine the respective limiting positions of the arm 136; the rods are secured to a fixed arm 185 by means permitting separate longitudinal adjustment. U.S.A. Specifications 2,368,066, 2,386,800, and 2,389,151 are referred to.