Patent GB-191309841-A (GB)
Title: Buttonhole Cutting and Stitching Machine.
Inventor: FAIRWEATHER WALLACE
IPC: D05B3/08
Filed: 1913-04-26
Granted: 1914-04-27
Abstract: 9841. Fairweather, W., [Singer Manufacturing Co.]. April 26. Button-hole sewing- machines.-The normal position of the workclamp is between the retracted position of the cutters and the stitching point. The cutters are moved up to the work-clamp in its normal position for t h e cutting operation and the work-clamp is moved to the stitching point for the stitching operation. Or, the corresponding relative movements between the cutter, work-clamp, and stitching point may be otherwise effected. The invention is shown applied to a machine having double - loop stitch - forming devices as described in Specification 9460/12, a workclamp, its mountings and their connexions with the feed-cam 64, as described in Specification 14,682/12, a stop motion and a cutter shaft 91 and clutch gear as described in Specification 9459/12; t h e needle being cut before the button hole is stitched. When the machine is at rest, the work-clamp is open and is in cutting position to the rear of the stitching - mechanism. T h e cutting device is in its extreme retracted position beyond the workclamp and its cutting elements are separated. When the cutter shaft 91 is set in motion by the manual operation of the cutter-shaft clutch, the cutter levers 108. 109 are first moved by cam action on their pivot block bodily towards the cutting position and carry w i t h them a clamp - closing lever 223 which is pivoted on the member 108 and is rocked by a cam 220 on the cutter shaft to depress a tappet arm of the workclamp into clamp-closing position. Immediately following this, the cutter members close upon the fabric. As the cutter members come together upon the work, a cam-button 36 is turned by the pitman 80 and the cutter shaft to spread or separate the two pairs of clamps which form the work-clamp and so ensure the cutting of all the strands. During the separation and retraction of the cutter members, the feed-cam 64 receives its initial turn from a pawl carried by a slide 250 connected adjustably to a slotted cam-lever 242, and moves the workclamp up to the stitching point. The stop-gear lever 140 is swung outwards by means of a lever 145 and a cam-plate 147 on the cutter shaft 91 as this shaft completes a full rotation and thereby the stitch-forming mechanism is set in motion. During its operation, the feed-cam 64 receives its normal slow feed movement from the usual clutch-dogs and this proceeds until, at the completion of the second side of the buttonhole, a tripping-lug 162 adjustably secured on the work-clamp slide 25 encounters a nose of a plate 158. This the lug thrusts aside, and a tripping lever 156 upon which it is mounted is moved to release the stop-gear lever 140 which assumes stopping position under the action of its spring. The rise of the block 139 of the stop-gear as it rides upon the clutch ring causes the engagement of a pin 195, Fig. 4, with a link 193 pivoted upon a lever 188 and by the subsequent downward movement of the block 139 into the notch of the clutch ring, the belt pulley is unclutched, the stitching operation is terminated, and a normally retracted but continuously jogging pawl 173, operated directly from an eccentric 165 on the belt pulley of the clutch, is brought by the movement of the link 193, lever 188, and lever 182 into operative relation with ratchet teeth 174 of the feed-cam 64. The step-by-step return movement of the feed-cam to initial position under the action of the pawl 173 causes the return of the workclamp from stitching to initial cutting position at a speed exceeding that of the normal feed movement. At the completion of the stitching operation, the rise of the block 139 carrying with it a lever 227 causes the tilting of a rocklever 232 the end 235<1> of which depresses a tappet arm and opens the work-clamp. Feedcam operating-mechanism as described in Specification 9842/13 may be used in connexion with the invention, and accelerating-mechanism for reducing the time between the cutting and stitching operations may be set into action by the starting-device or cutter mechanism. Governing needle thread.-The lever 188 communicates its movement at the stopping of the machine to a rod 203 and wedges 216, 207 are caused to separate the tension disks of both upper and lower stitching-threads.