Patent GB-191303293-A (GB)
Title: Improvements in or relating to Buttonhole Sewing Machines.
Inventor: HILL GEORGE S
IPC: D05B3/08
Filed: 1913-02-08
Granted: 1913-10-09
Abstract: 3293. Hill, G. S. Feb. 10, 1912, [Convention date]. Button-hole sewing-machines; needles, driving; governing needle-thread; governing underthread.-The invention consists in improvements in the stitch-forming mechanism, the workclamp and its actuating-means, the cutting- mechanism, and the driving-gear for the various parts. The frame 1 carrying the operative parts is connected to the base 2 by trunnions 3, Fig. 1, to facilitate inspection. The workclamp comprises a carriage 5, Figs. 4 and 7, having work-supporting plates 4 pivoted to it at 6 so that they are separated to stretch the work by a stationary cam when the carriage is advanced to the sewing position. The clamps 7, Figs. 10 and 12, are mounted on arms 8 pivoted on the plates 4, and are closed by a lever 33, 37 which is actuated by a projection 39 on the cutter-arm 29. The clamp is locked in its closed position during the sewing-operation by the engagement of a latch 44 with a spring-pressed one-way latch 45, 46 on the frame as shown in Fig. 12. The backward movement of the clamp-carriage at the end of the sewing- operation releases the latch 44, and a coil spring acts on the arm 33 to open the clamp. The clamp-carriage 5 has bearings 50, 51, Fig. 7, on the frame, and is moved longitudinally by a camgroove 53 in a gear-wheel 31, Fig. 10, engaging a roll on a stud 54. The pivot-block of the stud slides in a slot in the frame. The carriage is swung laterally by a lever 57 actuated by a cam-groove on the face of a gear-wheel 60, Fig. 4, and connected to the carriage by a block 58 engaging a slot 59. The cutting-mechanism comprises a supported lower block 22, and a cutter blade 24 carried by an arm 25 mounted on a yoke 26 pivoted at 28, Fig. 1. The yoke is rocked to actuate the cutter by a bell - crank lever 29 pivoted on its rear side and having one arm engaging a cam 30 on the gear wheel 31, and the other arm engaging an adjustable set-screw 32 on the yoke. The stitch-forming devices comprise a straight upper needle 61, passing through the fabric, a curved eye - pointed under-needle 62, passing through the buttonhole slit, and a looper 63. During the sewing-operation, in order to form the stitches round the button-hole the stitch-forming mechanism is rotated once, the upper needle being mounted in a rotary sleeve 66 and the under-needle and looper in a rotary turret 88. The sleeve 66 and turret 88 are rotated by chains 70, 123 from a shaft 73 which receives its motion from the gear-wheel 60 by the link-and-cam device shown in Fig. 8. The shaft 73 is connected by a link 127 with a lever 125 pivoted to the wheel 60 at 126 and engaging by a roll 129 a cam-groove 130 in stationary cam-plate. The upper needle 61 is mounted eccentrically in a bar 65 which is reciprocated from a shaft 75 by a crank and link 74, 76. The shaft 75 is rotated to give a comparatively slow advance and a quick return to the needle by a connexion with the driving- shaft 78, with which it is out of alinement, comprising a crank-pin 79 engaging a radial slot 81, Figs. 1 and 4. The shaft 78 is connected with the main driving-shaft 84 by gearing 82. The upper thread passes through a tension 102, a pull-off device 101, Fig. 1, down through the hollow needle bar, and through a light tension 100 to the eye. A thread-engaging device for determining the slack given up by the needle comprises an adjustable sleeve 67 into which the needle-bar passes at the inner end of its stroke. The tension 102 is released periodically by a rod 202 acted on by a cam on the wheel 31. The thread is drawn off the end of the under - needle by a finger 101' reciprocated between guides 100 by the shaft 84. The underneedle 62 is carried by an arm 85, Fig. 12, pivoted on the turret 88 at 86, and having a curved slot 93 engaged by a roll on an arm 89 mounted on a sleeve 90 on a pivot shaft 91. The sleeve 90 is rocked by an arm 94 connected by a link 95 with a lever 96 which is actuated by a link 98, Fig. 1, connected to a crank on the main driving-shaft 84. The looper 63 is pivoted on one end of an arm 114, Fig. 11, mounted on a rock-shaft 115, the other end of the arm being guided in stationary cam-slot 119, or by a pivoted link. The rock - shaft 115 is actuated by a link 117 connected to an arm 118 on the sleeve 90. The under-thread t<1> passes to the needle 62 by way of the hollow link 95, a tension-device 106, and suitable guiding-eyes in the turret. The stay cord s also passes up the link 95, and in order to prevent twisting of the thread and cord, by the rotation of the turret, the supplying - devices, Fig. 4, are rotated in the opposite direction. The cord reel 140 and thread - guide 145 are rotated together by a chain driven by a shaft 134, Figs. 4 and 7. The stitch-forming mechanism is driven by a pulley 150, Fig. 1, which contains a friction - clutch for coupling it to the shaft 84. The clutch is put in when a pinion 157 is rotated by a rack 158, the pinion having cam means for moving it endwise when rotated. The rack 158 is actuated by a spring 163 and a cam on the face of the wheel 31. The shaft 84 is stopped in a determined position by the engagement of a cam 166, Fig. 1, with a conical roll 168 on an arm 167 which is actuated by a spring and a cam on the wheel 31. The wheel 60 that imparts the rotary movements to the stitch-forming mechanism is driven by a shaft 134. Fig. 4, to the upper end of which is connected a shaft 135 by a universal joint. This shaft carries a gear 136 driven from the shaft 84, and by changing the gear 136, the number of stitches round the button-hole may be readily altered. The cam-carrying gear-wheel 31 is rotated independently of the stitchforming mechanism during the cutting operation, but is rotated from the same source during the stitching operation. The gear 31 is driven by a pinion 177, Fig. 4, on a sleeve loose on the shaft 134. The sleeve is adapted to be clutched for the cutting operation to a gear 183 running loose on the shaft 134, and driven by a continuously-running shaft 186, and to the pinion 133 by a spring-pressed pin 180, for the stitching operation. The clutching is controlled by an arm 188 which is actuated through a gear-sector 198 by a cam groove in the wheel 31. The clutching is also controlled by the starting-finger 194 which engages a spring- pressed stop arm 191. The constructional arrangements may be modified. Specifications 13,877/12 and 15,777/13 are referred to.