Patent GB-190220358-A (GB)
Title: Improvements in Button-hole Stitching and other Overedge Stitching Machines.
Inventor: MACDONALD JOHN KING
Filed: 1902-09-18
Granted: 1903-09-18
Abstract: 20,358. Croll, J., Macdonald, G., and Macdonald, A., (trustees of Macdonald, J. K.), [Singer Manufacturing Co.]. Sept. 18. Buttonhole-sewing machines; frames; needle bars, vibrating laterally; buttonholes, barring.-Relates to a machine for sewing ordinary straight as distinguished from eyed buttonholes. The needle-bar 7, Fig. 2, is carried on a part a of the frame, which is oscillated laterally about pivots 9, 10 by a link 17. This is adjustably connected with a link 16, Fig. 15, for the purpose of varying the throw, and the link is reciprocated by a bar 15, which is notched so as to engage with either of two pins 23, 24 on a lever b pivoted at 14. The lever b is actuated by a cam-groove 12 in a wheel 11 from the main shaft 4, which makes two rotations for one of the cam. The pin 24 is about twice as far from the pivot 14 as the pin 23, so that the throw of the needle-bar frame a can be increased while the barring-stitches are being sewn. The movements of the bar 15 are effected by a spring 20, and also by a pawl 29 carried by a bell-crank lever 30, Fig. 2, which is connected with the workfeeding cam referred to below. The pawl 29 engages with a pin 28 on the bar 15, which is thus pulled from the over-seaming to the barring position. When the barring is completed, the pawl 29 is thrown off the pin 28 by an adjustable projection on a ratchet-wheel 36 actuated by a pawl 4U on the lever b. Arrangements are made for returning the wheel 36 to its initial position at the end of the barring operation. Feed; work-supports.-The feed-mechanism is shown in plan in Fig. 12. A cam-wheel 60 is actuated by a clutch from the main shaft 4, the connection between them being a rod made in two parts, which are connected together by a catch controlled by the bar 15. The catch is released and the feed suspended during the barring operation. The work is clamped on a plate 75 by a spring clamp consisting of arms 89 pivoted at 91 on the plate 75 and provided with serrated holding-dogs 87. The plate 75 slides longitudinally with respect to the buttonhole in a plate 76 which moves transversely. The motion of the plate 75 transfers the work from stitch to stitch, and is derived from the feed cam-wheel 60 through a lever 71 and link 73, which are adjustably connected together. The plate 76 moves the work sideways, so that one side of the buttonhole is first stitched and then the other. This motion is also derived from the cam-wheel 60 through a lever 78. The plate 76 carries an interchangeable raised throat plate 82, over which the work is moved and which is furnished with a longitudinal slot 86 to receive the knife for cutting the buttonhole after sewing, and also with a transverse slot for the needle, the two slots running into one another. The clamping-arms 89 are pressed down on the work by an adjustable spring and are controlled by a shaft 117, connected with the clutch-actuating lever 101 for starting and stopping the machine, so that when the machine is stopped the work clamp is automatically released. Stopping, automatic.-The stop-motion is similar to that described in Specification No. 8864, A.D. 1901. It consists of a friction-clutch device, as set forth in the former Specification, controlled by a lever 101 operated by a treadle through an arm 111, and containing a spring plunger, the upper end of which, shown at 113, operates the clutch, while the lower end engages with a hook connected with the shaft 117 above referred to. When in the driving position shown in Fig. 2, into which position the lever 101 is thrown by the treadle, an arm 110 projecting from it is caught by a lever 114. The opposite end of the lever is controlled by the ratchet-wheel 36, which regulates the barring, so that when the second set of barring- stitches have been made the arm 110 is released, and a spring 132 moves the lever 101 into the vertical position, thus stopping the machine. At the same time the lower end of the plunger contained in the lever 101 engages with its hook, while the end 113 snaps into a notch in a cam 103 on the main shaft, and the plunger can thus be forced upwards by its spring, lifting the hook 120 and turning the shaft 117. Governing needle thread.-The work clamp 89 engages with a rod 133 connected with an arm 135, which acts on the tension 136 and releases the upper thread when the operations are completed. Buttonholes, cutting.-A cutter 137 is carried on a bar 139 which is operated by a cam 143, Figs. 2 and 23, by means of a lever 141. The cam is carried loosely on a shaft 33 on which the feed-wheel is mounted, which shaft is surrounded by a spring connected at one end to a collar 145 fixed on the shaft, and at the other to a collar 147 having a spring-buffer connection with the cam. As the sewing proceeds, the spring is wound up, but the cam cannot rotate as it is engaged by a lug 152 on a stop-lever 149, which is pivoted to the framing of the machine, and is pressed upwards by a spring 150. As the feed-wheel rotates, the lug 152 is kept against a shoulder 157 on the cam by a collar 156 on the shaft 33, but, as soon as this collar presents an opening to the lug, the lever rises and releases the cam 143, which is, however, stopped after rotating a certain distance, by the engagement of a lug 153, also carried by the lever 149, with a stop 158 on the collar 147. The buffer connection of the cam and collar 147 prevents shock. Governing under thread ; overedge stitching machines.-The stitch is made by an oscillating shuttle operated from a rock-shaft 160, Fig. 7. In order to set the purl of the stitch on the upper side of the work, the under thread is clamped while the shuttle thread is being drawn from the bobbin for the succeeding stitch, so that the pull due to this cause is not communicated to the stitch which is being sewn. The bobbin has a projection 59, which has a notch to receive the thread. One side 164 of the notch is resilient, and is acted on at each stitch by a spring pin 169 carried by a lever, which is oscillated by an eccentric 167 on the shaft 160, thus clamping the thread. This device is applicable to overedge-stitching machines generally.