Patent GB-704631-A (GB)
Title: Button sewing machines
IPC: D05B3/14
Filed: 1951-08-10
Abstract: 704,631. Sewing-machines. MAXANT, W. T. Aug. 10, 1951, No. 18850/51. Class 112 Starting and stopping. In a button-sewing machine having a rotary shaft actuating stitch - forming mechanism through a plurality of stitch - forming cycles, stop motion means includes an arm extending transversely from and rotating with the shaft, a stop bumper mounted on means movable longitudinally in a direction substantially parallel with the shaft, a hand lever extending upwards through the machine base for moving the bumper mounting means to a position in which the bumper does not engage the stop arm, and means actuated automatically on completion of said plurality of stitch-forming cycles to move the bumper into position for engagement with the arm. In the machine shown, a rod 40 slidable parallel to the main shaft of the machine carries a beltshifter 36, a flat member surrounding the shaft and provided with a brake lining 38 to engage the face of the fast pulley 33, and a stop member, provided with a buffer spring, arranged to engage an arm on the shaft when the rod is in its rearward position to stop the machine. Rebound of the shaft from the stop member is prevented by a detent 82, Fig. 6, which is pulled, by a spring, behind a shoulder on a collar 81 on the shaft; while the machine is running the detent is held clear of the collar by a cam portion of a sliding bar 85 connected to the rod 40. The rod 40 is held in the running position shown, against the action of a spring 43, by a spring-biased' latch 58 engaging a depending block 57 on the rod, the latch being released, at the end of a stitching cycle, by a trip member on the cam 71 engaging an adjustable nose 67 on a transverse member 65 pivoted at 66 and overlying the latch 58. The rod 40 is moved to the running position, to start the machine, by a hand-lever 48 engaging a pin 50 on the stop member; a treadleoperated crank 51 is also provided for the same purpose. Buttons, attaching. The work-clamp comprises a base-plate 86, Fig. 9, a workplate 92 fixed to the base-plate, and an arm 88 pivoted to it and carrying adjustable button-clamping jaws 90; the plate 86 is slotted longitudinally to slide and swing about a fixed screw 94, and receives longitudinal reciprocating movements, for placing two holes in a button alternately under the needle, from a pin 96 carried by a lever 98, Fig. 6 (underneath view), and swinging movement, to shift a four-hole button from the position for sewing through one pair of holes to that for the other pair, from a pin 95 connected to a link 112. The lever 98, pivoted at 99, carries a pin 103 which can be shifted along a slotted arm 105 oscillated by a pattern cam 72, and the link 112 has a pin 114 engaging a slotted arm 116 actuated by a cam 71; the link 112 has a projecting handle 113 for shifting it to a position in which the pin 114 is concentric with the pivot of the arm 116 when a two-hole button is being sewn and no shift is required. The clamp is lifted by a treadleoperated linkage, shown in Fig. 9, with a spring arranged to press it on to the work. Loop-stitching. The needle-bar 11, Fig. 9, is connected by a short link to a rocking: lever 14 oscillated by an eccentric 19 on the main shaft. The looper is formed with: an axial stem which is clamped in a stepped sleeve fixed on the end of the main shaft. A thread-deflecting plate close behind the looper is carried by a rock-shaft oscillated by a cam on the main shaft engaging an arm on the rock-shaft. The thread passes through two tension devices 145, a pull-off 143, guide 152, thread lock 156, eye 155 on the needle-bar, and guides 154. Threads, controlling otherwise than in stitch-forming. On completion of a stitching cycle, a cam lug on the shaft of the' cams 71, 72 actuates a lever 175 to operate a linkage which closes the thread lock 156 to clamp the thread. The lock 156, Fig. 10 (not shown), comprises a plunger, normally spring-pressed rearwardly against a stop, which is pushed forward through a resilient connection by the operating linkage' to clamp the thread against a fixed front plate. Lifting of the button clamp breaks the thread beneath the work, and a pin 137 on the forward-moving member 128 of the clamp-lifting linkage operates' a spring-returned bell-crank carrying an upstanding member 143, through which the thread passes, to pull off thread for starting the next cycle of stitching; the thread also passes through a hole in a stop pin 142 for the crank. Thread spoot holders. The thread supply is carried by a pin on a bracket 147 covering and shielding the belt pulleys and bearing a post 151 with a thread eye in its upper end, which is bent forward to lie over the axis of the spool. Frames. The bed 2 of the machine is hinged at 3 on one side to a base 1, and is normally secured in operating position thereon by a screw 4 on the opposite side. The work is carried by a narrow extension 6, which encloses the looper. The front face of the machine head is open, being closed by a cover-plate 10.