Patent GB-594985-A (GB)
Title: Improvements in or relating to the securing of shoe uppers to insoles or in or relating to machines suitable for use therefor
IPC: A43D25/06
Filed: 1945-04-09
Abstract: 594,985. Boots and shoes. BRITISH UNITED SHOE MACHINERY CO., Ltd. April 9, 1945, No. 8677. Convention date, April 12, 1944. [Classes 17 (i) and 17 (ii)] A shoe upper is secured in lasted relation to a lipped insole by activating an adhesive located between the margin of the lasted upper and the insole by the heating effect of a highfrequency electric field produced between electrodes on opposite sides. The lasting, particularly at the sides, may be done by a gripper 44, Fig. 2, pulling successive portions of the upper heightwise and then inwardly from the edge of the last in co-operation with an electrode 42 movable to lay the margin of the upper inwardly of the insole in a direction inclined relatively to the plane of the shoe bottom so as to force the edge of the upper into the angle between the insole feather and lip, the latter being supported by an electrode 46. The mechanisms for operating the gripper and electrode in correct time relation are substantially as described for corresponding mechanisms in Specification 283,978 [Class 17 (i)]. The lasting at the toe and heel ends may be performed. each at a single operation in a bed lasting machine, Figs. 3, 4, 5, by a pair of wiping elements shaped to the contour of the end portion of the last and mounted for bodily movement lengthwise of the shoe and for swing- ing movement laterally of the last towards and away from each other. At the toe end, Fig. 4, the electrodes 60, 62 form the wiping elements and are mounted on a lasting head 64. They' work in conjunction with an electrode 56 arranged to engage the bottom face of the insole and to support the inner face of the insole lip. The toe lasting head 64 with the electrodes 60, 62 and a toe band 66 are movable heightwise of the last by a double-acting treadle 65 connected by a link 61 to a slide 69 on which the head 64 is supported so that, during or after the inward wiping movement of the electrodes, pressure may be applied to the overlasted margin of the upper. The electrodes 60, 62 are connected to the high tension side of an oscillator 57 and the electrode 56 to the other the circuit of the oscillator being closed by a switch 67 normally open but closed in response to further depression of the treadle 65 to increase the pressure on the electrodes. The electrode 56 is supported on an arm 68 on the upper end of a rod 81 connected at its lower end by a link 83 to a treadle 85 held normally in upraised position by a spring, and locked in depressed position by a pawl and ratchet mechanism 87. It can thus be moved into and out of position over the toe end of the insole and downwardly into engagement with it. A similar arrangement is employed for heel lasting in the same machine, electrodes 70, 72 connected to the high tension side of a high frequency oscillator 90 being moved to wipe the margin of the upper inwards over the heel end of the insole. The opposite side of the oscillator is connected to the last pin. 52 which is in contactwith a metal plate on the bottom of the last at the heel end and which constitutes an electrode 86 for co-operation with the electrodes 80, 72. A switch 88 is actuated by a treadle 82 in similar manner to the switch 67 mentioned above to close the circuit of'the oscillator 90 when the wipers have been actuated to hold the overlasted margin of the upper against the insole. A high frequency electric field may be used to activate cement by which in a subsequent operation a sole is attached. The electrodes are preferably of copper and have polished surfaces and rounded edges to avoid arcing or corona effect. The adhesive employed may be a thermo-plastic vinyl resin or thermosetting resin composition of urea or phenol formaldehyde and may be applied to the margin of the insole and outer face of insole lip and to the various layers of the shoe upper before assembly on the last. Specification 594,993 also is referred to.