Patent GB-496888-A (GB)
Title: Improvements in or relating to sewing machines
IPC: D05B85/00
Filed: 1937-06-07
Abstract: 496,888. Sewing-machines. AMERICAN MACHINE & FOUNDRY CO. June 7, 1937, No. 15727. Convention date, March 11. [Class 112] The machine, for stitching neckties, is of the type employing a double-ended needle 20 alternately grasped by the jaws of opposed needle bars 22, 23, and includes automatic means to stop the machine so that the needle eye is aligned with a horizontal threader. Other objects of the invention include a device to ensure the needle enters a needle bar to a pre-determined depth, and driving gears for the tie-carrying platform so that work is done while the platform is moving both forwards and backwards. The needle bars are actuated by rocker arms 25, 26, and links 27, 29, through a plate 30 controlled by rollers R, R<1>, in a cam groove on the driving plate 64. The hooked threader 31 is secured in a sliding bar 33 which is pressed on to its baseplate by a spring-pressed plate 38, Fig. 15. A handle 45a, pivoted at 46, is pressed backwards to thrust the threader 31 through the eye of the needle 20, a thread is placed over the hook, and the threader withdrawn under action of the spring 41. Jaws 53, 54, which grasp the thread after the threader has returned to normal position, are opened by means of a roller 56 bearing on a surface 53a, when the lever 45a is rocked on its pivot. When the machine is to be stopped, a brake band 70, Fig. 2, grips the driving plate 64 and as the plate slows down a lever 96, Fig. 3, is swung against the plate and makes contact with an abutment 90 so that the plate 64 stops in a position coinciding with the needle eye being in line with the threader. When a driving motor is switched on, a solenoid 87 pulls on a lever 78, and withdraws the stop 96 from the path of the abutment 90, and at the same time a rod 77 presses against a lever 72 to release the brake band 70. A stop 80a limits the travel of the lever 79, and a spring 98 absorbs the shock when the abutment 90 strikes the stop 96. The driving motor is energized when an external switch and a hand switch are closed in succession. The motor is stopped by means of a pin on the work platform opening the. hand switch. This also de-energizes the solenoid 87, and the brake band 70 is applied to slow down the driving plate 64. The platform is driven by a motor through chain gearing and a gear 135, Fig. 10, through gears 139, 121, and a rack 120, in one direction, and a gear 122 and the rack, in the opposite direction. A handle H turns a shaft 124 to right or left, so that either gear 121, 122 is moved by pin and slot mechanism to engage the rack. The handle H may also close the electrical circuit. Fig. 13 shows a means to limit the depth of penetration of the needle 20 in either needle bar, and comprises a fixed plate 155 in each holder. The needle is non-circular, preferably triangular, in cross-section, and is caused to be pulled by one needle bar, and pushed by the other through the fabric. This is secured by designing the cam groove 64a, Fig. 1, in the plate 64, so that before one holder reverses direction the two holders continue moving in the same direction for a short time.