Patent GB-533183-A (GB)
Title: Buttonhole sewing machine
IPC: D05B3/06
Filed: 1939-10-13
Abstract: 533,183. Sewing-machines. FAIRWEATHBR, W. C. (Singer Manufacturing Co.). Oct. 13, 1939, No. 27889. [Class 112] Relates to button-hole sewing-machines in which the total relative movement between the work and the stitchforming devices is invariable, in which the feed cam is driven through alternative gears, one of which provides for. a rapid actuation of the cam, when the machine is not stitching, and in which the period of the stitching operation is controlled by a pattern cam in gear with the feed cam. The rapid feed gear is put into operation by the closing of the work clamp and is thrown out by 'the stitch-starting devices. In the case of eye-less button-holes, it is put in again for the turning of the end of the buttonhole by a device moving with the clamp and taken out when the 'end is turned by a lug on the pattern cam. At the end of the stitching, the rapid feed is put in by the stitch stop gear and is taken out by a second lug on the pattern cam when the clamp reaches its initial position. The stitch starting and stopping parts of the pattern cam are symmetrically adjusted by a single knob. Lateral movement for a full eye-end is provided by the feed-cam but for smaller eye ends and the barring stitches and during the straight stitching, the lateral position is given by the pattern cam. The rapid feed mechanism, which is controlled by the longitudinal movement of a rod 49, and the means for putting it in by the closing of the clamp and the stitch stop gear and for finally taking it out are the same as in previous machines. It is put in, when desired, for the rapid turning of the button-hole end, by a trip 93, Fig. 2, carried by a rod 96 attached to the feed-clamp which engages an arm 99 on the known trip shaft 66 and it is taken out in known manner when a lug on the rear of the pattern cam trips a lever 78, Figs. 7 and 10, having a pin-and-slot connection with the latch 63 which holds the rod 49 in rapid feed position. In order to permit this action during the continued stitching, the rapid feed is taken out at the commencement of the stitching by means of a lever 88, pivoted co-axially with the lever 78. This lever has a shoulder 89 arranged to co-operate with a shoulder 84 on a trip 83 pivotally carried by the lever 78. When the clamp is being moved rapidly to the initial stitching position, these shoulders are in line and the movement of the stitch starting rod 33, for initiating the stitching, causes the lever 88 to despress the lever 78 to remove the latch 63 and permit the rod 49 to move into the position shown in Fig. 10. The rise 37 of the stitch-starting cam piece 115, however, then gives a. further movement to the parts 33, 88 carrying the shoulder 89 below the shoulder 84 so that the trip 83 cannot return to bring the shoulders in line and they are unable to prevent the latch 63 from rising during the continued stitching when the rapid feed is put in for turning the end of the button-hole. The lateral position of the work-clamp is mainly determined by a peripheral groove 123 in the pattern cam in which rides a pin 22 carried by a lever 21 which controls the lateral movement of the clamp. When large-eyed buttonholes are being stitched, the pattern cam raises the pin 22 out of its own groove and into engagement with a lever 20 operated by the feed cam, so coupling the levers 20 and 21 together. The pin 22 may, however, be raised into permanent engagement with the lever 20. For this purpose, the pin has an arm 23 which normally rides in a slot 24 in a sleeve 25 but can be moved to lie on the upper surface of the sleeve. The stitch starting and stopping cam pieces 115, 119 are carried on two discs 102, 103 mounted behind a clamping plate 104 on the pattern cam body 100 and are circularly adjustable in opposite directions by pinions 108. 112 turned by means of a knob 113. The peripheral groove 123 has no cam portions and for making taper-bar hutton-holes cam-grooved pieces 124, 125 are secured to the discs 102, 103 so as to overlie the groove 123. On meeting these pieces, the pin 22 rides up the inclines 128 into the camgrooves 127. The length of the taper-bar is determined by adjusting the cam pieces 115, 119 and the cam slots 127 are long enough to secure that the pin 22 rides in them at the starting and stopping of the stitching. The floors of the grooves 127 do not raise the pin 22 into engagement with the lever 20 of the feed cam. For making small-eyed button-holes, a earn piece 132, Fig. 17, is secured directly in the pattern. cam groove and acts similarly to the pieces 115, 119. For making Large-eyed button-holes, an ungrooved piece ,131, Fig. 16, is secured in the pattern cam groove and this piece raises the pin 22 into engagement with the lever 20 so that the lateral movement for the eye formation originates with the feed cam.