A venting unit is inserted in a press fit within the air vent of a rubber article forming mold and is comprised of a cylindrical body member with an axial bore having a reduced outer end section forming an air inlet open to the mold cavity. Received for reciprocal axial movement within the bore between an inlet closed position in abutting engagement with the outer end section and an inlet open position removed from the outer end section is a heat absorbing piston or disc. The opposite or inner end section of the bore receives a vented plug in a press fit to form a radially inwardly projected shoulder and a spring is held in compression between the disc and the shoulder of the vented plug. During expansion of the rubber article, pressurized air in the mold cavity urges the disc to its inlet open position and is vented to the atmosphere. As the rubber article reaches its final form, venting of air is completed and any uncured rubber in the air inlet contacts the disc to set the rubber within the confines of the air inlet. The rubber in the air inlet forms a part of the molded article which, upon its removal from the mold, will exhibit only a minimal surface irregularity.
A mold for curing a green tire which is made of an elastomeric material capable of flowing prior to curing. The mold includes a surface defining a cavity in the mold for receiving the green tire. A passage communicates the cavity with the exterior of the mold. A vent plug is located in the passage. The vent plug has an opening extending therethrough communicating the cavity with the passage. Elastomeric material may flow into the opening to form a projection extending from the tire as the green tire is pressed against the surface defining the cavity during a molding operation. The vent plug has a portion extending into the cavity a predetermined distance from the surface to form a recess in the tire adjacent the projection. The recess provides a space that the projection may deflect into to prevent shearing off of the projection during removal of the tire from the mold.
The invention relates to a vulcanization mold for producing rubber goods, especially vehicle tires. The mold has a number of deairing holes into which blocking mechanisms are introduced. The blocking mechanisms ensure, especially by means of the air duct being bent, that the air can be drained without any disadvantageous flash being produced. In a second embodiment, the blocking mechanisms forms a two-part valve with the central body. In this case, the blocking mechanism has an elastically deformable planar area placed on the inside of the mold which acts at least essentially as a seal in conjunction with the central body when impinged upon by the surface of the blank.
A pneumatic tire comprising a tread portion, a pair of sidewall portions and a pair of bead portions is manufactured by conducting the venting in a portion of a green tire placed in a vulcanization mold prior to vulcanization and corresponding to the sidewall portion in at least one place in a radial direction of the tire during the vulcanization.
6871831 - Mold vent - Owned by The Goodyear Tire & Rubber Company (Akron, OH)
A vent for a mold having a mold cavity comprises a valve member housed within a main body sleeve and reciprocally moveable therein in an axial direction between open and closed positions. The sleeve is mounted within a mold wall and contains an expansion agent such as silicon. An increase in mold temperature causes the expansion agent to expand and move the valve member from the closed position into the open position. An external annular groove is provided within the sleeve to receive displaced mold wall material as the sleeve is press inserted into the mold wall. A tight fit of the sleeve within the mold wall results. The sleeve and valve are configured to allow air to escape in the open position. The valve member is moved to the closed position by material within the mold cavity pressing against the valve member.
