Patent GB-191214993-A (GB)
Title: Improvements in Buttonhole Cutting Mechanism for Sewing Machines.
Inventor: FAIRWEATHER WALLACE
IPC: D05B37/02
Filed: 1912-06-27
Granted: 1912-10-17
Abstract: 14,993. Fairweather, W., [Singer Manufacturing Co.]. June 27. Button-hole sewing- machines.-The buttonhole-cutting mechanism is arranged so that the thrust of the co-operating cutting-members is transmitted directly to the upper and lower members of the machine frame, thereby obviating any springing or bending of the moving parts. The machine comprises a laterallyjogging reciprocating needle 194 and a complemental stitch-forming mechanism 199. The frame 1 has a central web 2, Figs. 1 and 4, and an arm 5 strengthened by flanges 6. The upper cutting-member 51 is carried by an arm 44 mounted on a rockshaft 47, and is actuated by a rod 33, and toggle-link mechanism 37, 40 connected to the arm 5 by a pin 38. In cutting, the thrust is transmitted through the straightened toggle to the arm 5. The lower cutter 53 is carried by an arm 57 fulcrumed at 59, Fig. 1, in a hanger 60 which is pivoted on a shaft 63. To bring this cutter into position, the hanger 60 and arm 57 are rocked independently. In order to transmit the thrust directly to the frame web 2, a block 107, Fig. 4, is rotated into position between the block 56 carrying the cutter 53 and a seat 108 on the web 2. The arm 57 is operated by a cam 74 on the rock-shaft 47 of the upper cutter, engaging a pin on a tail 71, and by a cam 151 secured to a feed-controlling lever 127. The hanger 60 and the thrust-taking block 107 are operated by a tail-plate 79 attached to the arm 44. The hanger shaft 63 has an arm 87 connected to a plate 89, and the block 107 is mounted on a shaft 104 which is rocked by bevel-gearing 93 from an arm 97 which has a plate 99 connected to it. The plates 89, 99 are similar, each having a cam-groove 92 engaged by pins 83 on opposite sides of the plate 79, and notches 91 entered by clutch pins 80. By this means, the hanger 60 and block 107 are operated in proper sequence from the upper cutter member 44. Locking levers 114, 115 are provided to secure the parts during the cutting operation. The work-clamp 149 is operated by a feed-rod 147 jointed as shown and driven from a rock-shaft 135 by rack-andpinion gearing. One section 131 of the rod slides in a member 126 which is carried by an arm 127 pivoted at 128 to an arm 129 pivoted to a frame stud 130. The member 126 is raised to draw the clamp out of the way of the cutting-mechanism by an arm 75 on the rockshaft 47. A pin 76 on the arm engages a cam-slot 124 in a lever 123 pivoted at 122, and connected to the bar 126 at 125. The cutting-mechanism is put into and out of operation automatically by a finger 185, Fig. 2, on the feed-shaft 135 which has a to-and-fro motion. The actuating-arm 33 is connected to a crank-disk 28, which is driven intermittently by a worm 26 on a continuously running shaft 25 gear-driven from the shaft 16. The wormwheel 28 has a spring-pressed sliding toothed section 161, Fig. 7, which is held out of contact with the worm 26 during the sewing operation, but is released for the cutting operation by a system of latches and levers 168, 170, 164, 181, 188, 184, the last-mentioned being actuated by the finger 185.