Patent GB-811605-A (GB)
Title: Improvements in or relating to sewing machines suitable for use in sewing together an upper and sole member of a shoe
IPC: D05B15/00
Filed: 1957-01-11
Abstract: 811,605. Welts &c. butting; sewing machines. BRITISH UNITED SHOE MACHINERY CO. Ltd. Jan. 11, 1957 [Jan. 13, 1956(2)], No. 1102/57. Classes 17(1) and 112 In a machine adapted to sew together a shoe sole, a shoe upper and a strip of material such as a welt or rand, the latter is arranged to be severed by means controlled or operated electrically. In the machine shown in Figs. 2, 4, 6, 23, which is similar to that described in Specification 418,823, a shoe upper 2, an insole 4 and a welt 6 are sewn together by an inseam. The welt is led into position by a guide 16, after passing through a supporting enclosure 54, and is severed by a magnetically-operated knife 14 which moves in the space between the guide and enclosure, the arrangement being such that severing takes place while the machine is in operation and the bevelled cut exactly matches the initially bevelled front end of the welt, the sewing being allowed to continue for a few stitches into said front end. The knife is connected by a bar 42 to the armature 40 of a solenoid 38 which, when energized, moves the knife downwardly to sever the welt, the knife being moved upwardly by a spring 48 when the solenoid is deenergized. The guide and enclosure are carried by a bar 56 which is suspended by pivoted links 76, 78 in such a manner that the guide and enclosure can move in a path coincident with that of the curved needle. A feeler 12, adapted to be engaged by the front end of the welt, is carried by one arm of a three-armed lever 80 pivoted on a fixed pin 82 on which is also pivoted a triangular plate 84. Lever 80 is biased anti-clockwise by a spring 95, acting on the second arm of the lever, to bring the third arm into engagement with a pin 83 on plate 84. Said third arm is connected by a link 86 to one arm of a two-armed lever 88, pivoted at 90 to plate 84, the other arm of lever 88 carrying a stud 92. Plate 84 may be moved from an inoperative position, when feeler 12 is raised above the shoe, to an operative position when feeler 12 is positioned adjacent the shoe and stud 92 is positioned adjacent the button of a switch 94 in the circuit of solenoid 38. Movement of plate 84 is effected by a bar 104 pivoted at one end to the plate and having at its other end a pin-and-slot connection 106 to an .arm 108 fixed to a journalled shaft 110. A spring 118 biases the latter anticlockwise, against the force of a weaker spring 124, to bring an arm 112, connected to arm 108, into engagement with a fixed pin 123, and thereby to maintain plate 84 in the inoperative position. Shaft 110 may be rocked clockwise by means of a cable 138 connected to an arm 122 fixed to shaft 110, to allow spring 124 to move plate 84 to the operative position, determined by the engagement of plate 84 with an adjustable stop 174. Plate 84 is held in the operative position by means of a latch bar 96 which is pivoted at 90 to plate 84, is biased towards bar 104 by a spring 132, and is formed with a notch 98 which engages the squared end of a shaft 100. Cable 138 is connected to one arm of a bell crank lever 154, the other arm of which is connected by a link 158 to a lever 160 which carries a knee pad 172, the movement of lever 160 being limited by the respective engagement of a pair of opposed studs 166 thereon with a fixed stop 164. When pad 172 is pressed to move plate 84 to the operative position, a stud 176 carried by lever 154 closes a switch 178 in the circuit of solenoid 38. When the front end of the welt engages the lowered feeler 12, lever 80 is moved clockwise against the bias of spring 95, and link 86 moves lever 88 anti-clockwise, whereby stud 92 closes switch 94 to energize solenoid 38 and operate knife 14. If the operator sees a projection on the shoe' liable to cause premature actuation of feeler 12, pad 172 may be released, when a spring 180 moves lever 160 to the inoperative position, whereby switch 178 is opened and operation of the knife is prevented, said movement of lever 169 being permitted by the pin-and-slot connection 106 and the flexibility of cable 138. To enable the machine to operate on shoes in which the welt is attached to the forepart of the shoe only, means are provided for holding plate 84 in the inoperative position and switch 94 closed, so that knife 14 will be operated whenever the knee pad 172 is actuated. Said means comprise a pivoted arm 204 provided with a cam surface (not shown) and a pin 210, and held by a toggle spring 206 either in a raised or in a lowered position. When arm 204 is lowered manually, said cam surface closes switch 94 and pin 210 abuts lever 88 to prevent movement of plate 84. To enable the feeler 12 to operate reliably when a light, flaccid welt is being sewn, a spring-biased head is so arranged that it is engaged by the leading end of the welt. whereby the latter is supported in part by the head and in part by the shoe upper when it is engaged by the feeler. The severed end of the welt remaining in the enclosure 54 is advanced into the welt guide 16, after the machine has been stopped, by a swinging toothed segment 214 pivoted at 216 to one arm of a lever 218 fulcrummed on shaft 100. Segment 214 is normally held out of contact with the welt by a spring 296. When knife 14 descends, a cam projection 224 on the knife bar 42 co-acts with a roller 222 carried by lever 218 to force segment 214 against the welt in a channel 226. A double-armed latch lever 234, fulcrummed at 235, is then biased by a spring 236 to engage a pawl arm 232, secured by a screw 237 to the other arm of lever 218, to hold the segment in its welt-engaging position. A finger 240, carried by said other arm of lever 218, also raises latch bar 96 to free the latter from shaft 100, whereby plate 84 returns to the inoperative position. Segment 214 is connected by a link 282 to an arm 281 fixed to shaft 100. Another arm (not shown) fixed to the latter is connected by a link 279 to one arm of a bell crank lever 274 fulcrummed at 276. The other arm of lever 274 is connected by a link 272 to the strap of an eccentric carried by a shaft 262 adapted to be driven by a one-revolution clutch. A lever 242, fulcrummed at 244, is adapated to be swung, when the machine-stopping gear comes into operation, in a manner described in Specification 630,242, by a plunger mounted coaxially with the main cam shaft 30. Movement of lever 242 is transmitted by a cable 248 to an arm 256 fixed to a rock shaft 258, whereby a stop arm 260, also fixed to the latter, is disengaged from the one-revolution clutch. Shaft 262 then rotates to swing lever 274 and thereby to swing segment 214 for feeding the welt. A cam 264, carried by shaft 262, co-operates with a lever 266 adapted to stop shaft 262 upon the completion of a revolution. An arm 288 fixed to shaft 100 is pivoted to one end of a link 290, the other end of which is connected by a pin-and-slot connection 292 to a second arm of the latch lever 234, whereby the first arm of the latter is disengaged from the pawl arm 232 at the end of the welt-feeding stroke of segment 214, spring 296 then lifting segment 214 from the welt. In the machine shown in Figs. 27 to 37, which is similar to the machine described in Specification 532,026 and modified as described in Specification 665,713, the out-turned margin of a shoe upper U, an outsole O, and an L-shaped rand W are sewn together by a lockstitch seam S. The stitching is performed by a curved hooked needle 412 and a curved awl 414 which oscillate in a fixed plane P. The work is clamped between a support 418 and presser foot 420, both of which are carried by a pivoted carriage 432 which oscillates to feed the work. The rand is led into position by a main guide 422 and a supplementary guide 440, both of which are mounted on the carriage 432. The rand is severed, at a position eight or ten stitch lengths away from the plane P, by an upwardly-moving knife 426 slidably mounted in a block 430 fixed to carriage 432, the knife entering a slot 434 formed in guide 422. The knife is formed with a series of holes 442, into any one of which can be screwed a stud 443 which passes through a block 444 and also through a slot in block 430. Block 444 is embraced by a forked arm of a bell crank lever 446, pivoted adjustably at 448 on block 430, the other arm being connected by a link 450, a lever 454, and a link 456 to the armature 457 of solenoid 458. Energization of the latter thereby rocks the lever 446 to actuate the knife, the armature being returned to its original position by a spring 464 on de-energization of the solenoid. A feeler 470, formed with a hook-shaped shoe-engaging end, is pivoted at its other end, at 472, to a member 474 slidably mounted on a fixed bracket 478. A member 482, projecting from feeler 470, is acted upon by a leaf spring 490 to bias the hooked end of the feeler against the shoe. A cranked bar 494 is secured adjustably at one end to the slider 474 by means of a pin-an-slot connection 496, 498, the other end of bar 494 overlying the plunger 492 of a switch 491 fixed to bracket 478 and connected in the circuit of solenoid 458. When the initially-sewn front end E of the rand engages the hooked end of the feeler, the latter is moved bodily, whereby bar 494 engages plunger 492 to close switch 491, normally when said hooked end overlies the knife 426. To prevent premature actuation of the knife, e.g. when the feeler passes over a seam 502, a switch 504 is also connected in the solenoid circuit, and is closable by means of a manuallyoperable latch lever 514, adapted to engage the plunger 512 of the switch, after seam 502 passes the feeler end. A fixed pointer 506 is provided to assist the operator in determining the proper time to close switch 504. A further switch 542, also connected in the solenoid circuit, has a plunger 544 adapted to be engaged, for closing the switch, by plate 546 extending from carriage 432, when the latter reaches the end of