Patent ID: 6875004

Claim:
An apparatus for extruding unvulcanized rubber which comprises a first extruder main body for extruding a first unvulcanized rubber, a second extruder main body for extruding a second unvulcanized rubber, an extrusion head which connects a leading end of the first extruder main body and the second extruder main body, and a passage-forming die for guiding, at a leading end of the extrusion head, the first unvulcanized rubber and the second unvulcanized rubber toward a die plate having an opening, wherein an extruded rubber member is formed by extrusion, the extruded rubber member having a cross sectional configuration in which, when seen from a cross section perpendicular to a direction in which the extruded rubber member is extruded, a portion of the second unvulcanized rubber intrudes into the first unvulcanized rubber and a portion of the first unvulcanized rubber is disposed at both sides of the intruded second unvulcanized rubber, said apparatus further comprising: a first passage through which the first unvulcanized rubber passes; a second passage provided adjacent to or connected to the first passage and through which the second unvulcanized rubber passes; and a flow dividing mechanism provided at one of a portion at which the first passage and the second passage are disposed adjacently and a portion at which these passages are connected, that separates a portion of the first unvulcanized rubber passing through the first passage to allow the first unvulcanized rubber to be disposed at both sides of the intruded second unvulcanized rubber in a direction intersecting a direction in which the second unvulcanized rubber intrudes, wherein the flow dividing mechanism includes a first weir disposed at an upstream side of the die plate and apart from the die plate, and protruding from the second passage side toward the first passage in a direction perpendicular to a direction in which the unvulcanized rubbers pass, and a partition wall extending substantially perpendicular from the first weir in a direction away from the die plate, one end portion of the first weir is connected to the passage-forming die and the other end portion thereof is disposed at a portion substantially corresponding to a widthwise intermediate portion of the opening of the die plate, the widthwise direction corresponding to a direction in which the first weir protrudes.