226 



THE INDIA RUBBER WORLD 



[February 1, 1916. 



Some Molds for Seamless Rubber Goods. 



THE desire of manufacturers to produce better and more 

 satisfactory rubber goods has encouraged study of the ways 

 ^r making seamless articles to replace those formerly 

 turned out with cemented seams. 



SHAPING MOLDS FOR SEAMLESS HOT WATER BOTTLES. 



The manufacture of seamless blown goods such as hot water 



bottles offers many interesting problems. These must be intelli- 



HoT Water Bottle Funnel Shaping Mold and Core. 



gently considered and accurately solved before the finished 

 product can be placed on the retailers' shelves with any degree 

 of confidence in the stability of the goods. 



It would seem that the building up of hot water bottles by 

 hand, formerly the exclusive method of manufacture, would result 

 in a more perfect article than can be produced by standardized 

 mechanical means. This may be so in a few specialized instances. 

 There are many who still stand by the time-honored hand meth- 

 od ; but the trend is toward the mold shaped and cured bottle as a 

 more perfect and less costly article. Just how these are made is 

 interesting and instructi\f. 



the mold and the core with the threaded end, covered completely 

 with a special rubber compound, is slipped over the vertical pins 

 that hold the core in place in the lower mold. Another piece of 

 regular stock cut to suitable size is placed over the upper half 

 and the two parts aligned by dowel pins are then fitted together, 

 with the core between them, and placed under a hydraulic press. 

 Thus, the seamless funnel and stopper socket with its soft, 

 hard rubber threads and hanging tab are shaped up ready to be 

 attached to the body ])ortion of the bottle. By the way, the 

 stopper is also made of this special stock, but in separate molds 

 that are very like those just described. The metal reinforcement 



Fig. 2. Hot Water Bottle Sh 



In making one class of bottles, shaping molds are used which 

 are in reality dies that make all the would-be seams, seamless, 

 and at the same time bite off the overflow of surplus rubber 

 from the edges. These dies consist of two sets, one for shaping 

 up the funnel with its threaded socket for the stopper and another 

 which forms the body of the bottle. 



Fig. 1 shows the two-part funnel mold and core. In use, 

 a piece of regular sheeted rubber stock, cut approximately to the 

 required size, is laid on the lower mold. A metal reinforcement 

 for the stopper socket is then placed in the constricted end of 



Fig. 3. Flu.sh Tank Bulb and Metal Cap. 



of the stopper and threads is covered with stock of the same 

 compound as that of the funnel socket. 



The next step in the process is to shape up the body portion 

 of the bottle and at the same time attach the funnel which is done 

 by the dies shown in Fig. 2. A sheet of regular stock is laid over 

 the lower mold or die and the funnel core supporting the shaped- 

 up funnel itself is placed in the constricted part of the mold 

 with the threaded portion occupying its proper position in the 

 neck of the bottle mold. The other end of the core extends 

 outside of the molds and is provided with a valve through which 

 air is pumped or "blown" through a hole in the core, into the 

 interior of the bottle. 



When the funnel core has been properly arranged in the lower 

 mold another sheet of regular stock is laid on the upper mold 



Fig. 4. Tank Bulb Hinged Shaping JiIolds and Cone Plate 

 Shaper. 



and pressed in place, after which both molds are placed together 

 and subjected to hydraulic pressure. At the same time air is 

 forced into the bottle to prevent the sides from sticking together. 

 The action of the dies is not only a forming one, shaping and 

 practically welding all joints into a homogeneity, but a shearing 

 one by which the overflow is smoothly and neatly trimmed from 

 the outside edges. 



The seamless water bottle is now almost finished; however, 

 there still remains the final curing or vulcanizing process, which 



