Patent GB-762193-A (GB)
Title: Improvements in or relating to sewing machines for operating on shoes
IPC: D05B15/00
Filed: 1953-12-02
Abstract: 762,193. Sewing-machines. BRITISH UNITED SHOE MACHINERY CO., Ltd. (United Shoe Machinery Corporation). Dec. 1, 1954 [Dec. 2, 1953], No. 33437/53. Class 112. [Also in Group XXIV] In a shoe sewing machine comprising a jack 18 for supporting a shoe, means including a pattern cam-shaft 22 for. imparting movement to the jack so as to transfer the point of sewing operation automatically about the shoe, means for driving the machine and for bring- ing it to rest at the end of a sewing operation, and auxiliary drive mechanism for completing rotation of the pattern cam-shaft thereafter, a brake is provided for acting on the pattern cam-shaft, said brake being released when the auxiliary mechanism is in operation and being re-applied on completion of said operation, the brake also being released when a treadle 4 is depressed to start the machine, and also during the operation of means which are provided for reversing the rotation of the pattern cam-shaft. The jack is urged to the operating position by yielding means and is moved away therefrom by the straightening of a toggle, said straightening being normally effected by a connection from the pattern cam-shaft, while a treadle 165 is so arranged that it may be operated either to break the toggle or to straighten the latter. Driving.-The driving means, which are generally similar to those described in Specification 548,344, comprise a main clutch having a driving member 45, Fig. 1, and a driven-shaft 25. carrying at one end a gear 46 which meshes with teeth formed on a cam disc 206 carried by the shaft 208 for driving the stitch-forming means. The other end of shaft 25 slidably carries a clutch member 24 movable by means of an arm 61 into and out of engagement with a clutch member 26 carried by a shaft 30, and the. latter is connected by a train of gears 32, 34, 36, 38, 40, 42, 44- to the pattern camshaft 22. The main clutch is adapted to be closed by means of a rod 48 connected to the treadle lever 4 which is pivoted on a fixed spindle 47. Arm 61 is formed with a V-shaped notch engaged by the rounded end of an arm 130, pivoted on a spindle 132. Arm 130 is also connected to a clutch member 124 slidably mounted on a continuously. rotating shaft, member 124 being movable either upwardly to engage a clutch member 128 for driving the auxiliary mechanism for completing rotation of shaft 22, or downwardly to engage clutch member 122, the latter carrying a gear 118 which meshes with gear 36 to drive shaft 22 in the reverse direction (for correcting faulty work). Movement of member 24 in either direction serves to rock arm 61 for opening clutch 24, 26. At the end of the stitching operation rod 48 is tripped to open the main clutch. In addition, clutch 124, 128 is closed, whereby clutch 24, 26 is opened and a spindle 62, Fig. 3, is rocked clockwise, when a tooth 72, carried by an arm 68 pivoted to a crank 64 fixed to spindle 62, is moved over a plate 70 secured to gear 44, and engages behind said plate. Spindle 62 then rocks anti-clockwise, whereby tooth 72 rotates gear 44 to complete the rotation of shaft 22. A handle 136 fixed to spindle 132 is biased upwardly by a spring 134, to carry a spring-biased dog 140, pivoted to the handle at 138, into engagement with a fixed pin 142 and a pin 146 on the handle. The latter may thus be moved downwardly to close clutch 122, 124 and open clutch 24, 26. The handle is made flexible so that it may be moved sideways to disengage dog 140 from pin 142, whereby the handle moves upwardly, till pin 146 engages a fixed abutment 150, to open clutch 24, 26 but insufficiently to close clutch 124, 128 when shaft 22 may be rotated manually. The brake for the pattern cam-shaft comprises a conical braking member 74, Fig. 2, slidably mounted on a spindle 76 upon which the gears 34, 36 rotate, member 74 being normally biased by springs 104 into engagement with a conical recess in gear 34. When treadle 4 is depressed to start the machine, a collar 110 on rod 48 rocks a spring-biased bell crank lever 112, whereby a roller 116 on the latter rocks a yoke 94, which is pivoted on a spindle 96, when a pair of pins 102 carried-by the yoke release member 74 from gear 34. In order to release the brake when the auxiliary mechanism is operating, a segment 90 fixed to spindle 62 is formed with a cam portion 106 which co-operates with a roller 92 on yoke 94 to rock the latter. The brake is re-applied when roller 92 rises into a recess 108 provided in segment 90, at the end of the movement of spindle 62. For releasing the brake during the reverse operation of shaft 22, an arm 151 is secured to spindle 132 and overlies a plunger 152 passing axially through spindle 76, whereby when handle 136 is depressed, arm 151 moves plunger 152 downwardly to engage a pin 86 carried by the braking member 74. Work Supporting.-The jack is mounted in the manner described in Specification 551,662, and the jack-supporting rod 19, Fig. 1, is pivoted to a bell-crank lever 169 which is fulcrumed on the spindle 47 and is acted upon by a spring 170 adapted to urge rod 19 upwardly to the operative position. A pair of toggle links 154, 156 pivoted at their respective outer ends to lever 169 and a fixed spindle 158, are adapted when aligned to lower the lever 169 against the bias of spring 170. A spring acts on the pivotal connections between the links to bias the latter to the aligned position. At the end of the sewing operation, a collar 160 on the end of a rod 159, actuated by the stopping mechanism, acts on a projection on link 156 to straighten the toggle. A lever 164, pivoted at 168 to lever 169, carries at one end the treadle 165 and is pivoted at its other end to a link 166 which is in turn pivoted to link 156. The arrangement is such that pressure exerted on the outer edge of the treadle serves to rock lever 164 and thereby break the aligned toggle, while pressure exerted on the treadle immediately above pivot 168 serves to lower the jack from the operative position and to align the toggle. Stitch forming, thread tensioning.-Thread passes from a tension wheel 173, Figs. 1 and 10, to a pulley 176 mounted on the end of a take-up arm 172 pivoted at 174. The shaft 171 carrying the tension wheel also carries a brake drum 178 which is engaged during normal operation by a main brake shoe 180. On completion of a seam, shoe 180 is disengaged from the brake drum, and the latter is then engaged by an auxiliary brake shoe 190, which remains in position until the first stitch of the succeeding seam is completed, when it is disengaged and the main shoe comes into operation. Shoe 180 is pivoted to a lever 182, and a tension spring 186 is interposed between an adjusting screw 184 carried by lever 182 and a link 188 connected to the take-up arm 172. A rock-shaft 196 carries an L-shaped arm 194, an arm 198, an arm 202 provided at its free end with a roller 204,-and an arm 212. At the end of a sewing operation, a member 200 is given a slight movement and thereby moves arm 198 to bring roller 204 into contact with cam disc 206 on the sewing shaft 208. The latter, which normally rotates anti-clockwise as seen in Fig. 10, is reversed a short distance after being stopped at the end of a seam, whereby roller 204 enters a groove 210 in cam 206 so that shaft 196 is rocked to carry arm 194 into contact with a screw 192 on lever 182, thereby lifting shoe 180; and arm 212 is raised sufficiently to be held by a latch 214 pivoted at 191. Shoe 190, which is also pivoted at 191, has pivoted thereto a block 220 carrying a rod 218 which is slidable in a block 216 pivoted to arm 212, a compression spring 222 being interposed between blocks 216 and 220. Upward movement of arm 212 thereby urges shoe 190 resiliently against the brake drum. Stitch forming, thread cutters. thread-end holders.-A thread finger 13, Fig. 11, is formed as a hook on an arcuate bar which is slidably supported in a guide 228 and is formed with a rack which meshes with a gear quadrant 230 pivoted at 232. A link 234 connects quadrant 230 to a cam lever 236 which is pivoted at 238 and carries a roller 240 co-operating with a cam disc 241 carried by the sewing shaft 208. During normal operation, roller 240 travels in an outer slot 242, but when shaft 208 is reversed at the end of the operation, roller 240 displaces a pivoted latch 250 to enter an inner slot 244 through an interconnecting slot 248. The finger 13 thereby draws the thread against a resiliently supported gripping member 226, and a thread cutter 224 is then actuated to sever the thread close to the finger 13. Roller 240 remains in the inner slot during the formation of the first stitch in the succeeding seam, and leaves the inner slot by means of an interconnecting slot 246 near the completion of the first revolution of the shaft 208. Specification 289,142 [Class 112] also is referred to.