Patent GB-763847-A (GB)
Title: Improvements in or relating to methods and apparatus for making shoes of rubber or rubber-like material
IPC: A43B13/32
Filed: 1954-04-06
Abstract: 763,847. Moulding rubber &c. shoes. INTERNATIONAL VULCANIZING CORPORATION. April 6, 1954 [April 28, 1953 ; Jan. 18, 1954], No. 10031/54. Class 87(2). [Also in Group VII] A hot last presses the lower margin of a footwear upper against a sole blank made of rubber or like material, at least part of the sole blank being subjected to heat directly from the last. Thus, an insole is not used or, if used, is perforated to allow the heat from the last to soften the rubber of the sole blank. As shown in Fig. 8, an upper 11 is secured to a last L heated by a resistance r<SP>1</SP>, and a sole piece S of rubber is pressed against the bottom of the last, whereby the rubber is made plastic and sticky and adheres to the inturned edges of the upper. At the same time the rubber takes the shape defined by a mould comprising heated side plates 31 and a heated base plate 33. To facilitate' transfer of heat from the last to the rubber, pins 37 projecting from the last may be pressed into the rubber : and when these pins are used an insole may be fitted to the upper prior to pressing. The pins may be circular or rectangular in cross-section, and the holes they make in the sole may be left empty or filled with plugs of cork or felt. The last may have a projection 41, Fig. 12, to produce a hollow 39, Fig. 13, in the sole, and this hollow may be filled with a blank of felt or cork, which may.be stuck to the underside of the sock lining. Fig. 11 shows a last in which the projection 41, embodying the heater r, is secured to a rod 45 which may be raised or lowered to vary the depth of the recess 39. The upper may be of canvas, leather or rubber. The invention may be used to secure a sole on the bottom of leg portions of overalls. The method may be carried out by the machine shown in Figs. 16, 18 and 20. Two cast aluminium lasts L, which may be right and left, are secured to a shaft 28 which may be turned manually by means of a handle 32 to position either last over a mould 31, 33. A flexible electric cable 66 runs through shaft 28 and thence by 64 into the lasts to heat them. Shaft 28 is carried by pillars 16 which are vertically reciprocable in stationary sleeves 14, the pillars being connected to an eccentric 70 and handle 74 by the manual operation of which a last may be lowered into the mould. During its descent the last is properly aligned with the mould by the entry of a finger 54 (secured to shaft 28) into a fork 58 (secured to a sleeve 14). If the last is not properly aligned with the mould, sloping surfaces on the fork move the finger (and hence the last) to one side and prevent damage. The mould comprises a bottom plate 33 and two side plates 31, Fig. 18 (which is a plan view showing only one plate), secured to plates 90, Fig. 20, incorporating heating elements r. The plates 90 slide horizontally on a frame 80, and are moved inwardly, to close the mould plates together, by pneumatic cylinders 100 acting through toggles 112, 114. The mould being thus closed (a sole piece 5 of rubber &c. having been placed therein) and the last, with its upper, properly positioned, upwardly-directed moulding pressure is applied to plate 33 by a pneumatic cylinder 162, Fig. 16, acting through piston rod 160, ball-joint coupling 156, shaft 154 and electrically-heated block 148. The admission of compressed air to the cylinders 100 and 162 is controlled by a valve 132 operated by a treadle 166. In a modification the moulding pressure is produced by a blowing agent incorporated in the sole piece S.