GB245219A - Improvements in or relating to sewing machines - Google Patents

Abstract

245,219. Walpole, H. E. C., and Keats & Bexon, Ltd. Oct. 9, 1924. Boot-sole sewing-machines; outsole-sewing.- The presser-bar is adapted to be given a lift of uniform amount above the work irrespective of the thickness thereof and the thread pull-off is also automatically adjusted by varying the needle stroke in accordance with the work thickness. The feed point is carried by the presserbar and is actuated by means comprising a lever moved in a horizontal plane by a cam on the main shaft. The machine, which is of the Blake type, comprises a needle-driving rocking lever 13 actuated by an eccentric 10, 12 driven bv the main shaft 5 and a rotary horn 4 containing a whirl also driven from the shaft by a train of bevel gearing of known construction. A disc 43 on the shaft 5 is provided with a cam 44 which engages a bowl on a horizontal lever 45 having a pin and slot connection with a lever 48 to which is pivoted a link 56 having a bifurcated extremity wherein is mounted in a curved slot 58 a pin 57 carrying the feed-point carrier 60. A lever 63 fixed on the pin 57 has a hooked extremity 64 which engages a pin 65 on the presser-bar 9. The presser-bar is raised by a lever 77 actuated by a cam 79 the lever bearing against a snail cam 70 mounted on the presser-bar and controlled by a spiral spring 74 surrounding the axes of the cam and connected at one end thereto and at the other to the lever 77. A pawl 81 which engages the toothed part 71 of the cam is actuated by a compensated rod 84 connected to a bell crank lever 86 operated by the lever 45. A pawl 98 engaging teeth 99 on the presser-bar is operated by a cam 90 and lever 91 acting through a compensated rod 94. This pawl is for the purpose of holding down the presser-bar as the needle is withdrawn from the work. A device for placing friction on the needle-bar comprises a block 100 against which bears a pin 102 pressed by a spring 103 adjustable by screws 104. Chain -stitching.-For the purpcse of varying the needle-stroke and consequent thread pull-off in accordance with the work-thickness the fulcrum 15 of the needle-actuating lever 13 is mounted on an adjustable post 16 the height of which is regulated by a lever 106 pivoted to the frame at 107 and resting on a pin in the presserbar and bearing on a stud 109 projecting from the post. The position of the stud is adjustable for varying the length of stroke.