| 摘要 |
<p>695,765. Extruding inner tubes for tyres. UNITED STATES RUBBER CO. Sept. 28, 1951 [Oct. 24, 1950], No. 22659/51. Class 87 (ii). Two different kinds of rubber, of different colours or of different physical characteristics, are fed into the high pressure chamber of an innertube extruder 10 so that one forms the tube proper B and the other forms a wide outer wall strip R bonded to the tube. The water-jacketed extruder 10 carries a spider ring 34 which, by means of the spider 36, supports a mandrel 37. The die 41 is mounted ,on the spider ring in such a manner that it may be moved slightly in a plane at right angles to the axis of the mandrel in order to adjust the relative thickness of various parts of the tube. This adjustment is made by .means of circumferentially spaced screws 45 whose inner ends bear on a ring 46 screwed to the die. Rubber R to form the bonded strip is delivered from a separate extruder (not shown) to the high-pressure side of the die through a tube 12. From the tube 12 it flows into an arcuate groove 58 which is formed between the parts 41, 43 of the die. The groove decreases in width from its central portion towards each end. It is partially obturated by means of the arcuate slit through which the rubber R flows into the die. In order to increase flow near the ends of the groove 58, the central portion is provided with arcuate baffles 62 which define a narrow slot 63 through which only a restricted amount of rubber will flow. To obtain the same effect, the width of the slit between the ribs 60 may be increased near the ends of the arc. Compressed air and talc is introduced into the extruded tube through a pipe 50. The extruded tube is bent by passing it around driven rollers as described in Specification 599,991. It is then cooled by a water spray, dried by compressed air and cut into C-shaped lengths.</p> |
