Method and device for manufacturing tire forming bladders

A method of manufacturing tire forming bladders having a general V-shaped cross sectional configuration formed by a pair of generally straight tapered leg portions which join at one end to form an apex of the V-shaped bladder, including the steps of, providing a curing mold having first and second half molds and an inner core;

• inserting a first end of the inner core into an opening formed in the first half mold to form a first generally straight tapered leg portion of a substantially V-shaped inner molding chamber;
• inserting the second half mold into an opening formed in the inner core of form an annular groove and a generally straight tapered second leg portion of said molding chamber therebetween, with said second leg portion joining with the first leg portion at said annular groove;
• feeding a mass of uncured rubber into an annular outer chamber formed on the outside of the second half mold which communicates with the annular groove of said inner molding chamber via a number of injection duct means arranged in a generally circular pattern in said outer chamber;
• moving an annular piston into the annular outer chamber of the second mold half after said second mold half is inserted into the inner core and subjecting said mass of uncured rubber to sufficient pressure to inject said uncured rubber from said outer annular chamber into the annular groove of said inner chamber via said injection duct means whereby the uncured rubber flows into the annular groove and then into the straight tapered leg portions of the inner molding chamber communicating therewith to form the V-shaped bladder;
• curing said rubber inside said inner chamber so as to produce a finished bladder;
• and extracting said finished bladder from said mold by removing said second half mold from the inner core and extracting said inner core from the first half mold.