IE39979B1 - Method for heat curing hollow spherical objects - Google Patents

Abstract

1452011 Curing hollow balls GENERAL TIRE & RUBBER CO 14 Aug 1974 [11 Oct 1973] 35812/74 Heading B5A [Also in Division A6] The adhesive securing the covers of tennis balls is heat cured in a continuous process whereby each ball is successively introduced through an air lock (60, Figs. 1 and 6, not shown) into a confining mould 28 housed within a curing environment 10 that is maintained at selected curing temperature and pressure, the ball then passing through the mould 28 for a selected cure time after which it passes into a cooling environment 72 maintained at a selected temperature, and from which it is removed by means of a discharge air lock (74, Figs. 1 and 4, not shown). The moulding apparatus is in the form of a spiral groove 30 in the mould plate 28, the cross-section being semicircular and of radius substantially the same as that of the balls. A plate 32 is rotated beneath the fixed plate 28 to move the balls along the groove 30 from the inlet 54 to the outlet at the rim the length of spiral 30 and speed of rotation providing the desired cure time. Separation of the plates 28 and 32 is adjustable by means of four units 38 attached to plate 32. Steam or electrical heating coils 78 and 80 provide the curing temperature, air pumped through inlet 76 the desired pressure. The cooling environment is in the form of tubing 72 surrounded for part or all of its length by water-carrying piping 82. The air locks (60, Figs. 1 and 6, not shown and 74, Figs. 1 and 4, not shown) may both be in the form of ball plug valves that have been modified for limited 180 degree rotation between positions where their central cavities are connected (a) to the interior of the apparatus or (b) to the exterior. The valves may be linked for corresponding action. Valve (60, Figs. 1 and 6, not shown) may be cycled on a time basis or as a function of the rotation of the plate. Smooth non- adhering surfaces are desirable for the plate 32 and groove 30 to prevent adhesion of the balls thereto; this may be achieved by metal plating or coating with fluorocarbon resin. An air lock may be provided between the curing chamber 10 and the cooling environment 72 so that different pressures may be maintained in the two regions. [GB1452011A]