Patent GB-565651-A (GB)
Title: Buttonhole sewing machine
IPC: D05B3/08
Filed: 1943-04-14
Abstract: 565,651. Buttonhole sewing-machines. FAIRWEATHER, W. C. (Singer Manufacturing Co.). April 14, 1943, No. 5971. [Class 112] Automatic means are provided to vary the relative feed between the needle and the work to increase or decrease the number of stitches at the eye-end of a buttonhole, and quickly operable manual means to vary the spacing of the stitches throughout the entire length of a buttonhole. The invention includes a second-feeding mechanism automatically operable for overfeeding the first-feeding mechanism to space more widely the stitches at predetermined portions of the buttonhole. When the buttonholes are to be hand-stitched, the machine operates to baste and cut the buttonhole by using manual means to disconnect normal cam feeds. The stitch-forming mechanism is of the type described in Specification 179,278, [Class 112], and includes a turret 6 carrying threaded and non-threaded loopers and a pair of loop - detainers. The usual turning movements to the upper needle and under looper mechanisms are secured through gearing actuated by the usual connections with the cam-groove 9, Fig. 2, in the feed cam 10. Detailed descriptions, of the. above mechanisms are given in Specifications 100,990, 183,873, and 231,081, [all in Class 112]. The work is held by a work clamp 11, of the travelling type, during the entire button-holing operation, the clamp being rapidly moved over a bed 1 to carry the work forwardly from the buttonhole cutting position, to stitching position, then more slowly moved step-bystep to place the stitches about the buttonhole and then rapidly restored to initial position. The clamp-plates of the work clamp 11 are secured to a cross-slide plate 12, Fig. 2, which is carried by a slide-frame 13 actuated by a link-connection 14, and feed-lever 15 having a follower 16 moving in a groove in the feed-cam 10. The plate 12 is shifted by a lever 17 connected with the cam 10 and a removable pattern-cam 18. The latter is secured to the end of a cross-shaft 19 connected by bevel gears 20, 21, Fig. 3, to the cam 10. The rapid feed of the work-clamp from buttonhole-cutting position to sewing position and return is as described in Specifications 183,873, [Class 112], and 507,318, and comprises a rapid-feed drive shaft 22 having a worm 25 in mesh with a gear 26 on the shaft 19. Secured to the gear 26 is the live element 27 of a clutch within which is located a driven element comprising a number of clutch-dog-operating levers with tails 29. When the tails are expanded by a cone 30, slidable on the shaft 19, the clutch is released and the shaft 19 disconnected from 22. When the cone 30 is withdrawn from the tails 29, the rapid feed is thrown in. Means to operate the cone shifting by an arm 31 clamped on a cross-slide rod 33, which is biassed by a spring 34, is described in Specification 507,318. The endwise movements of a push-bar 35, pivoted to a crank 36 are used at predetermined times in the stitching cycle to withdraw the cone 30 from the rapid-feed clutch and thereby effect the coupling of the shaft 19 to the drive shaft 22. The throw-out is effected by the spring 34. During stitching, the feed-wheel 10 is driven in a slow-step-by-step fashion from the shaft 23 through gears 40, from a pin-andstar wheel 41 driven through bevel gears 42 and vertical shaft 43. Fig. 18 shows a gear 40, meshing with a ring gear 45 in a peripheral groove 46, the gear 45 being secured to the face of a bevel gear 31 integral with the cam 10. Turning impulses to the gear 45 are transmitted by one of a number of pawls 48 engaging ratchet teeth 50 on the inner face of the gear 45. When the stitch-forming mechanism operates, the gear 45 drives the cam 10 through pawl and ratchet. In the present invention, the stitches around the eye of a buttonhole are not crowded, but spaced evenly by a third feeding mechanism which overdrives the slow step-by-step stitching feed, imparting to the feed-cam 10, stepby-step turning impulses of greater amplitude than those imparted by the normal slow stitching feed. The third feeding mechanism (see Figs. 4, 5, 6, 7) comprises a member 52 on the gear 20, a clutch spider 54 formed with recesses 55, each containing a clutch-element 57 engaged by a plunger 58 backed by a spring 59, the plunger forcing the element 57 toward the narrow end of the recess 55. The spider is oscillated continuously during the operation of the stitch-forming devices, by means of a lever 61 connected to a link 63 coupled to a vibratory lever 64 pivoted on a stud 65, Fig. 3. The lever 64 is vibrated by an adjustable eccentric 67 on a shaft 44. The stud 65 is on an eccentric and may be moved by a handle 71 to vary the movements of the link 63, and thus the spacing of the stitches. The handle has a spring-pressed detent which enters one of a number of holes. A roller 95, Fig. 4, on a lever 89 engages one of the cams 96, 97 attached to the gear 20. As the gear 20 is turned by the gear 21 on the cam 10, a cam 96 or 97 is brought into engagement with the roller 95, thus swinging the lever 89 down, and through the link 87, turning the plate-member 84 and release-cam 82 in counter-clockwise direction against the action of a spring 101. Turning of the release cam 82 in counter-clockwise direction relatively to the rollers 81 on the levers 78 enables the plungers 58 and springs 59 to wedge the clutch elements between the spider 54 and the member 52. When the stepby-step impulses imparted to the cam 10 exceed those delivered by the slow step-by-step stitching feed, the pawls 48, Fig. 18, and cam 10 turn in counter-clockwise direction relatively to the ring-gear 45, the pawls riding over the teeth 50 so as not to interfere with the intermittent rotation of the gear 45 transmitted by the gear train 40 throughout the whole stitching cycle. This operation increases the spacing between successive stitches. The lever 89 is supported on a tranverse slide 91 which is adapted to move endwise so that when stitching eyelet buttonholes, the roller 95 is controlled by the cam 96, or when stitching straight buttonholes, the roller is engaged by cam 97. The active periphery of the cam 96 is of sufficient length to maintain the third feeding mechanism in action long enough to distribute the radial stitches around the buttonhole eye. The periphery of the cam 97 is shorter as the number of stitches distributed around the end of a straight buttonhole is less than the above. A " pull-and-twist " rod effects the sliding of 91 and has an arm which enters one of three slots for " eyelet," " straight " or " reg.," the latter withdrawing the third-feeding mechanism entirely, so that the machine operates in the manner of previous machines. For handstitching buttonholes, the machine may be used to baste and cut the buttonhole. The plate member 84, Fig. 4, has a projection to which is fastened an arm 117. A hand-lever on a spindle 121 is used to rotate an arm 118, raise the arm 117 and free the clutch-dogrelease levers 78, thus enabling the clutchelements 57 to couple the spider 54 to the cupmember 52 and drive the cam 10 to machine in longer stitches. Specification 565,668 also is referred to.