Patent GB-191214620-A (GB)
Title: Feeding Mechanism for Buttonhole Stitching Machine.
Inventor: FAIRWEATHER WALLACE
IPC: D05B3/06
Filed: 1912-06-22
Granted: 1913-06-05
Abstract: 14,620. Fairweather, W., [Singer Manufacturing Co.]. June 22. Button - hole sewing- machines.-In a machine for sewing eyed lmttonholes, the stitch-forming mechanism makes a semirotation for laying the radial stitches around the eye of the buttonhole, being operated by a ratchet gear 137 through gear - wheels 135, 134, shaft 131, pinion 129 and rack 125, and pinion 130 and rack 126, and longitudinal movements are imparted to the work clamp by means of a rack-andpinion 96, 98 operated by a feed-wheel 101 associated with two ratchet gears 100, 104 which are actuated one before, and the other after the rotation of the stitch-forming devices to drive the feed-wheel in opposite directions. The three ratchet-gears are interconnected so as to render each other in turn operative and inoperative; the first is controlled by the starting-gear and the last controls the stopping- gear. With the stopping-gear are associated devices for turning the stitch - forming mechanism back to its initial position and for cutting the button-hole slit. One member of the compound slide supporting the work-clamp consists of a frame 67, Fig. 5, to which are secured strips 65 slidingly mounted in guide slots formed in the machine frame. The other member of the slide is a plate 71 which also forms the lower member of the clamp. It is slidingly mounted within the frame 67 and is coupled by a jointed rod 93 to the rack 96. Two equal upper clamp members 74 (one of which is shown only in part) are pivoted at 76 to a bracket 77 springing from the plate 71 and are pressed upwards by springs 83. The clamp is closed when a finger 78 is depressed, the shaft to which the finger is attached having a crank 79 engaging a slot in a pivoted yoke piece 82 which presses upon both the clamp members 74. A bowl 90 on the clamp base-plate 71 co-operates with a cam-plate 88 and a cam-slot 72 in the base-plate is engaged by an eccentricallyarranged needle throat 64 which rotates with the stitch-forming mechanism; by these devices the slight lateral movements of the work clamp are occasioned. The three ratchet-wheels 104, 100; 137 are driven by pawls 118, 119, 138 pivotally mounted upon a segmental carrier 111 supported upon a roller 112 and positively reciprocated by a cam-actuated lever 109 to which it is fixed. The pawls are normally held out of action by detents 151, 152, 153 respectively. When the starting-lever is depressed to start the machine, a finger 277 associated with it presses upon a part 160 of the detent lever 151 and allows the pawl 118 to become operative. The ratchet-wheel 104 and a gear-wheel 102 fixed to it rotate step-by-step until a pin 170 engages with a lever 166 and moves the lever so that one of its arms 161 turns the pawl back to its inoperative position. At the same time, by means of a rod 174 connected to a second arm 171, the detent 153 is moved to release the pawl 138 of the ratchet-wheel 137 which causes the semi-rotation of the stitch-forming mechanism. When that movement is completed, a projection 178 formed on a plate adjustably secured to the wheel 137 engages a lever 163, which returns the pawl 138 to the inoperative position, and through a rod 184 moves the detent 152 from the pawl 119. Thereupon, the ratchet-wheel 100 is operated, rotating the feed - wheel 101 in the reverse direction, and a lug 261 is brought back into engagement with a lever 167 by which the pawl 119 is returned to the inoperative position simultaneously, the lug 261 moves a lever 253 which causes the stoppage of the machine by removing a catch lever 245 from the position in which it engages the lever 225 and holds the starting-gear in " running " position. It also turns a lever 263 having an arm 141 serving as a detent to the wheel 137 and so frees the stitch-forming gear preparatory to its return rotation. The position of the lug 261 can be readily adjusted and simultaneously alters the lengths of both sides of the button-hole. The initial step-by-step rotation of the stitchforming mechanism is checked by an escapement comprising teeth 362 on a plate secured to an extension of the rack-bar 126 and a detent 370 pivoted upon a lever which is lifted with every return movement of the pawl carrier 111 by means of a connexion 374. Normally, the pawls rotate the ratchet-wheels two teeth at a time. The movement is reduced to one tooth at a time by means of a plate 187 when it is adjusted so as suitably to mask the ratchet-wheels. To start the machine, a starting-lever is depressed which transmits its motion to a shaft 224. A lever 225 fixed on the shaft 224 is thus lowered into position for engagement with the locking- lever 225 and a cam-surface on a lever 234 also carried by the shaft 224 moves upwards over a stud projecting centrally from a loose driving pulley and clutch member 14 and forces the pulley to move axially to bring the conical clutch surfaces upon it and upon a shaft 9 into driving relationship. The rotation of the feedwheel immediately removes the lug 261 from the lever 253; the catch-lever 245 thereby freed engages the lever 225 and holds it in the running' position. A further lever 269 fixed upon the shaft 224 is moved downwards communicating its motion to a crank 275 upon which is fixed the finger 277 for releasing the ratchet pawl 118. A catch lever 279 pivoted upon the crank engages with a pin 148 of a band brake 146, used to steady the motion of the feed-wheel, and assists in holding the parts in " running " position. At the close of a stitching operation, the catch lever 279 is released by means of a lug 282 on the feed-wheel. When the starting- mechanism is finally released by the catch-lever 245 and the lever 234 moves to open the driving- clutch, a plate 350 secured upon the lever 269 engages a trigger - plate 343 pivoted upon a lever 338 and thereby establishes a driving connexion between a buttonhole - cutting mechanism and a shaft 293, which is continuously driven through gearing 292, 288, 285 from a toothing 284 integral with the loose driving- pulley 14. At the completion of the cutting operation, a lever 355 is raised and with it a lever 309 which establishes a driving connexion between the shaft 293 and the stitch-forming mechanism, whereby the latter receives its return rotation. The driving connexions controlled by the levers 338, 309 are similar. Each comprises a worm 295, 296 and a wormwheel 297, 298. The worm-wheel has a portion of its toothing formed upon a sliding piece 300, Fig. 12, which, when it arrives at the position where it would otherwise engage with its worm, is pressed inwards out of operative position by the cam-edge 308 of the controlling-lever. To re-establish the driving-connexion, the controlling-lever is turned to remove the cam-edge 308 and so permit the outward movement of the sliding piece which brings the teeth on the piece 300 into mesh with the constantly rotating worm. The worm-wheel is then driven through a complete revolution until the piece 300 is again engaged by the cam-edge. The wheel is locked in the disengaged position by a spring plate 315 having a notch into which a lug 307 on the piece 300 is moved. A part of the complete rotation of the wheel 298 is used through the gears 321, 322 and the shaft 136 to turn the stitch-forming mechanism backwards through half a revolution, and the remainder is rendered ineffective by means of a dog 325 pivoted upon the wheel 322 and engaging at the end 326 with a lug 331 to communicate the motion to the shaft 136, which dog is moved out of contact with the lug by a fixed cam-plate 336 when the shaft has been turned through half a revolution.