Patent GB-476039-A (GB)
Title: Improvements in or relating to machines for sewing on buttons
IPC: D05B65/00
Filed: 1936-02-24
Abstract: 476,039. Sewing - machines. JACKSON, L. MELLERSH-. (International Button Hole Sewing Machine Co.) Feb. 24, 1936, No. 5553. [Class 112] A machine for sewing buttons on to work comprises a needle which is movable laterally in two directions by a carrier to pass through the holes of a button which is held in a fixed workholder, looper elements co-operating with the needle and being correspondingly movable. The machine forms one or two groups of stitches, each comprising a predetermined number of attaching stitches and a tying stitch, the thread being severed after each group ; for a four-hole button one group of stitches is formed through one pair of holes and then a similar group through the other pair, there being no thread connecting the groups ; for a two-hole button a single group of stitches is sufficient, but two separate groups may be formed through the same holes if desired. The machine runs continuously through the whole operation of sewing on a button, and is then stopped automatically by means which can be set to operate after the formation of one group of stitches and which, if not so set, are automatically moved, after one group of stitches has been formed, into position to stop the machine after a second group has been formed. The machine may be set to form one or other of two fixed numbers of attaching stitches in a group, the looper elements and needle carrier being operated by a cam which has two separate sets of grooves, either set being brought . into operation according to the number of stitches required, and is driven by correspondinglyvariable gearing from the main shaft which produces the strokes of the needle. The needle-bar 81 slides in guides 93, 96 mounted in flexible discs for universal movement in the frame and in a carrier 98 respectively ; the carrier 98 is formed by a bar which is slidable longitudinally in a pivotal supporting member 106 and is guided in a horizontal plane at 112. The needle-bar is reciprocated by a link 91 from a crank pin on a cam 89 on the main shaft 76, the cam 89 operating a take-up crank 88. The looper elements are carried by a shaft 79 which is oscillatable and movable longitudinally to correspond with the movements of the needle-bar carrier 98, the movements of both these members being controlled by a cam 129 on a vertical shaft 78 geared to the shaft 76. Oscillation of the carrier 98 on its pivot 106, to shift.the needle from one hole to another in the formation of a group of stitches, is produced by a link 113, Fig. 18, with a pin 120 engaging an arcuate slot in a lever 122, pivoted at 123, which carries two pins 125, 126 engageable respectively with cam tracks 127, 128 in the upper face of the cam 129. The pins 125, 126 are interconnected so that only one at a time can be engaged with the cam, and are shifted by an arm 139 of a lever L, pivoted at L<1>, engaging pin 125 ; the cam tracks 127, 128 are formed to give different numbers of oscillations of the lever 122 during one revolution of the cam 129 in order to form different numbers of attaching stitches in each group. Corresponding oscillation of the looper shaft 79 is produced by connections from a link 190 engaging a slotted lever 193 similar to 122 but operated by cam tracks 197, 198, corresponding to the tracks 127, 128, formed in the peripheral surface of cam 129 ; the lever 193 has pins 195, 196, similar to 125, 126, alternatively engaging the cam tracks and shifted by another arm of lever L, which has a third arm by which it is operated and held in either position. The amplitudes of the oscillations of the carrier 98 and looper shaft 79 are varied by shifting the pins of their operating links 113, 190 along the slots of the levers 122, 193 ; these pins are shifted simultaneously by moving a member 132 which is slidable on the frame and secured by a clamp 135. Longitudinal movement of the carrier 98, to shift the needle from one pair of holes to another of a four-hole button, is produced by a link 146, which is guided by a swinging arm 149, engaging a slotted lever 153 on a vertical shaft which is moved by engagement of a crank 155 at its lower end with a sliding member 156 operated by a cam 162 on a shaft 158 driven by gears 163 at half the speed of the cam-shaft 78 to shift the lever 153 after a complete revolution of the cam-shaft and shift it back after a further revolution ; the pin connecting link 146 to lever 153 may be moved to a position coaxial with the pivot of the lever, so that no longitudinal movement of the carrier 98 is produced when a two-hole button is being attached. Corresponding longitudinal movement of the looper shaft 79 is produced by a pitman 205 connected to an arm on the lower end of a vertical shaft 150 to which is fixed the arm 149 guiding the carriershifting link 146. The cam-shaft 78 is driven from the shaft 76 through a worm 25 and worm wheel 26, and in order to allow slight adjustment of the relative positions of the cam 129 and the needle the shaft 76 (with worm 25) is movable longitudinally by rotating a bearing bush, in which the shaft revolves but is prevented from sliding, screwed in a housing on the frame, the bush being fixed to a worm wheel engaged by an adjusting screw 211. In order to vary the number of reciprocations performed by the needle during one revolution of the cam 129, to synchronize with the varying numbers of needle shifts produced by the cam tracks 127, 128, the wheel 26 is not fixed to the shaft 78, but may be clutched thereto by a sliding member 214 provided with teeth which, in the disengaged position of the clutch, engage an indirect train of gearing 219, 216 connected to the wheel 26 ; the shifting of the clutch member 214 is produced by a lever 220 operated by the lever L which determines which cam track is in use. Starting and stopping gear.-The driving pulley 77 is free on the shaft 76, and houses a ring 276, Figs. 40, 46, which is also free on the shaft and is connected to the pulley through a cushion spring ; a disc 282 fixed on the shaft 76 carries a spring-pressed pivoted pawl 281 which normally engages the ring 276 to transmit the drive. This pawl is tripped out of engagement, to stop the machine, by a member 287 mounted slidably, with a cushion spring, in an arm 289 which can be rocked towards and away from the disc 282 in a direction parallel to the shaft. A spring-pressed dog 290 engages a notch in the disc 282 to prevent any reverse movement under the action of the cushion spring of the trip member 287 ; this dog is moved clear, when the member 289 is rocked away from the disc 282, by a push-rod 294 operated by a cam surface on the arm 289. The shaft 305, to which the trip arm 289 is fixed and which is connected by an arm 306 to a treadle for release of the trip to start the machine, has an arm 298 with a pivoted member 299 sliding on a spindle 265 and pressed downwards by a spring. The end of the spindle 265, on which the member 299 rests, is cut away to present a thin flat portion 303, so that the member 299 is supported in a high or low position according to the angular setting of the spindle 265 ; when in the raised position, it is engaged by a projection on the underneath face of the cam 129 after a complete revolution of the latter producing one group of stitches ; when in the lowered position, it rests on a sliding pin 311 which, after one revolution of the cam 129, is pushed up by a crank 310 operated by a cam 313 on the halfspeed shaft 158, Fig. 18, so that the member 299 is engaged by the projection on the cam 129 to stop the machine after two revolutions of the latter producing the two groups of stitches required for a four-hole button. Stitch-forming.-The elements co-operating with the needle 80 to form the attaching stitches comprise loopers 82, 83, Figs. 60, 64, fixed to a carrier 84 on the shaft 79, and loop spreaders 223, 224 pivoted to the carrier 84, with torsion springs and adjustable stops, to lie just above the loopers; the spreaders are operated by their tails engaging the edges of a cam plate 228 when the carrier 84 is oscillated relatively to the latter. On each descent of the needle, a loop of thread is formed round one of the loopers and its spreader, and when the needle is withdrawn the carrier 84 is oscillated so that the loop is spread and carried across to be penetrated by the needle in forming the next loop through the other hole of the button ; when the needle is forming this next loop, the carrier 84 is moved back to free the first loop, which is then drawn tight by the take-up 88, Fig. 1, and to allow the other looper to catch the second loop. After the required number of stitches (determined by the cam 129) has been made, the needle descends a second time through the same hole to form a tying stitch. For this operation the cam plate 228, which is stationary during the formation of attaching stitches, is moved, and a loop deflector 268 is brought into action, both these members being free on the shaft 79 and being connected by a pin 240 which is linked by a member 244, Fig. 1, to a pin 245 carried by a pair of cranks 246 on a shaft 249, the pin 245 being long enough to allow longitudinal movement of the loop deflector and cam plate with the shaft 79 without requiring longitudinal movement of the shaft 249. The shaft 249 is driven by worm gear 251 from a vertical shaft having at its upper end an arm 254 carrying a pair of pins 255, 256 for selective engagement with a pair of cam tracks 257 formed in the underneath face of the cam 129 and corresponding to the other pairs of tracks on this cam ; the pins 255, 256 are arranged in a similar manner to the other pairs of pins engaging the cam 129, and are selected by a lever 261 having a forked end engaging a cam 264 on the spindle 265 which sets the stop gear. After the descent of the needle completing the last attaching stitch of a group, the looper carrier 84 is only moved half the normal distance to the right, th