Abstract: A composite insulator includes a hollow and tapered core portion composed of fiber-reinforced plastics, and a sheath and sheds composed of an insulating polymeric material integrally molded on the outer surface of the core portion. The core portions of composite insulators for a plurality of voltage classes are formed by using a mandrel assembly in which a plurality of mandrel members are combined. The so-prepared core portion is placed within a mold unit in accordance with the voltage class of the composite insulator to be manufactured, and the insulating polymeric material is poured into the mold cavity to integrally mold the sheath and the sheds.

Abstract: A securing method including the steps of inserting a core into a depression portion of a metal member having an open end portion, and connecting the metal member to the core by compressing circumferentially the core and metal member by means of a compression die is disclosed.

Abstract: A coating apparatus for coating an outer peripheral surface of a rod-shaped workpiece with a covering material, comprising an elastic body having a covering material-impregnatable property and provided with an insertion hole through which the workpiece is to be passed, and a moving mechanism for moving the workpiece relative to the elastic body through the insertion hole, wherein the outer peripheral surface of the workpiece is coated with the covering material impregnated in the elastic body, when the workpiece is passed through the insertion hole of the elastic body by the moving mechanism.

Abstract: A composite insulator having a core member and a housing member integrally arranged around the core member, the housing member being constructed by a trunk portion and a shed portion, has a creepable distance extending means arranged on a lower plane of the shed portion. Moreover, a segment used for producing the composite insulator has a pair of segment molds detachably connected at a partition plane having a through-hole at its center portion through which the core member is arranged, an upper plane forming portion arranged at its one end surface for defining an upper plane of the shed portion, and a lower plane forming portion arranged at its other end surface for defining a lower plane of the shed portion; and a partition for forming the creepage distance extending means arranged at the lower plane forming portion.

Abstract: A composite electrical insulator (1) includes a plastic rod (2), e.g., an FRP rod, which is covered by a sheath which includes a resilient and electrically insulating material. A metal fitting (4, 5) on each side of the insulator (1) has a radially inwardly deformable sleeve portion formed with a bore in which the end portion of the plastic rod (2) is covered by the sheath (3). The end portion of the sheath (3) has an outer surface opposite to the metal fitting (4, 5), which is provided with at least one circumferential ridge (7a, 7b).

Abstract: A metal fitting for a composite electrical insulator (1) including a plastic rod (2), e.g., an FRP rod. The metal fitting (4) includes a radially inwardly deformable sleeve portion having a bore (5) into which an end portion of the rod (1) can be inserted for fixedly securing the metal fitting (4) to the rod (1). The bore (5) in the metal fitting (4) has an inner surface which is formed with fine protrusions (7). These protrusions (7) provide a satisfactory resistivity to the tensile force applied to the insulator (1), to thereby effectively prevent withdrawal of the rod (2) from the metal fitting (4) when it is in use.

Abstract: A process for producing, by compression molding, an insulator having a core and a housing consisting of a sheath portion and at least one shade portion around the sheath portion, including the steps of: (A) preliminarily forming a rubbery layer around an outer periphery of the core to obtain a preliminarily molded body by extrusion molding, (B) placing the preliminarily molded body between at least two mold units of a mold; (C) forming a compressed molding by compression molding said preliminarily molded body in a given shape inside a cavity defined by the at least two mold units; and (D) curing the resulting molding. An apparatus is also disclosed for producing such an insulator by compression molding, which apparatus includes (A) a preliminary molding unit, (B) a molding unit form forming a compressed molding from the preliminarily molded body in a given shape by using a mold, and (C) a heater for curing the rubber in the rubber layer.

Abstract: A process for insulating high voltage conducting media by insulating such media with a silicone rubber composition capable of being converted to a rubbery elastomer superior in high voltage electrical insulating characteristics is provided. The composition comprises the following components (a) to (e) and not containing a platinum catalayst:(a) 100 parts by weight of an organopolysiloxane gum;(b) 10-100 parts by weight of a finely divided silica filler;(c) 15-300 parts by weight of aluminum hydroxide;(d) 1-20 parts by weight of a OH terminated organosilane or organosiloxane oligomer; and(e) 0.05-6 parts by weight of an organic peroxide.

Abstract: The disclosed insulator has one or more sheds integrally formed with the central core so that each shed extends radially outward from the core. Each shed has an annular rib extending downward from the lower surface thereof, and the lower edge of the rib extends outwardly with respect to the central core.