Patent GB-190405621-A (GB)
Title: Improvements in Buttonhole Sewing Machines.
Inventor: FAIRWEATHER WALLACE
Filed: 1904-03-08
Granted: 1905-02-09
Abstract: 5621. Fairweather, W., [Singer Manufacturing Co.]. March 8. Buttonhole-sewing machines; buttonholes, barring; ; feed ; needlebars, vibrating laterally. -Relates to improvements in the barring- mechanism of the buttonhole-sewing machine described in Specifications No. 20,358, A.D. 1902, and No. 1936, A.D. 1904, whereby either or both ends of the buttonhole may be barred with any desired number of stitches, or the barring may be omitted. Also in the feed mechanism so as to produce a few fastening stitches at the close of the cycle. The needlebar is vibrated laterally, through levers 16, 17, Fig. 2, by one of two pins 23, 24 on a camactuated lever b, which alternately engage slots 25, 26 in a rod 15. For side-stitching, the rod 15 is held in engagement with the inner pin 23 by a spring 20. At the proper times, to produce the increased vibration for the barring operations, a snail cam on the feed-wheel shaft relieves a spring- controlled lever 30, which, acting against the weaker spring 20, by means of a catch 29, moves the rod 15 into engagement with the adjustable outer pin 24. The snail cam is single or double for the production of buttonholes barred at one or both ends respectively. The movement of the rod 15 allows a pawl 40, carried by the lever b, to fall into engagement with a wheel 36. This is then rotated, until a bent trip-lever 53, Fig. 4, mounted on the cover-plate, and actuated by contact with a bent plate 52, moves the catch 29 to the left thereby freeing the rod 15. The rod is then drawn into engagement with the inner pin 23 by the spring 20, prior to resuming the side stitching operation. In so doing, the pawl 40 and a detent 45 are lifted from the wheel 36, which is returned to its initial position by a barrel spring 46. The number of barring stitches is proportional to the duration of this rotation, and that is determined by the position of a stop 48, against which the wheel 36 is held during its inoperative period. The stop 48 is part of a lever 57, which is clamped in position on the cover-plate according to the number of barring stitches required. If no barring stitches are required, this lever is moved to the zero position, where it bears against the trip-lever 53, causing that lever to hold the catch 29 continually out of action. To effect the same for long periods, a lever 81 is provided, the end of which may be interposed between the frame and the lever 30 so as to hold it out of engagement with the snail cam. The lever 81 is pivoted at 82 under a spring washer 84, and is held in either position by projections on the plate 83. During the barring operation, the feed is suspended. To permit this, the feed-wheel is rotated by a silent ratchet which grips an annular ridge of square cross-section on the under face of the feed-wheel, and is driven from an eccentric 150 on the main shaft by the mechanism shown in Fig. 7, as described in the Specification previously quoted. While the rod 15 is in position for the barring operation, its tail-end holds a catch lever 67 in the dotted position, and thereby disengages the eccentric-rod from the enveloping rod 152, and suspends the feed motion. The work-clamp is mounted on a compound slide, which is actuated in the two directions at right-angles by camgrooves on the feed-wheel. The groove causing the longitudinal motion is concentric at the point corresponding to the finish of the buttonhole in order to cause the formation of a number of superimposed fastening-stitches. Stopping-gear.-As described in Specification No. 18,153, A.D. 1903, the stop-motion comprises a spring-pressed plunger and a belt fork swinging on trunnions on the frame and controlled by a treadle-lever. The device is retained in operative position by a catch lever which enters a slot in the treadle-lever. To stop the machine, this catch lever may be withdrawn by a thumb-lever, or is automatically withdrawn at the close of the operation by engagement with a projection on the cam-wheel. In stopping the machine, the plunger engages a stop on a disc which is yieldingly connected to the fast pulley by a buffer spring, as described in Specification No. 17,998, A.D. 1903.