GB446674A - Improvements in means for moulding and vulcanising gas expanded rubber boards or other similar articles - Google Patents

Abstract

446,674. Expanded rubber; moulding. ROBERTS, D., 277, Park Avenue, New York, U.S.A. Nov. 1, 1934, No. 31355. [Classes 70 and 87 (ii)] Relates to a process for the manufacture of gas expanded rubber in which a rubber mixture is impregnated with inert gas at a high pressure, e.g. 3000 lbs. per sq. inch, heated to entrap the gas and finally placed in moulds and heattreated for vulcanization and expansion to a desired form. According to the invention, during the final treatment the moulds are passed through a conveying system comprising two opposed endless belts and are heated and maintained under pressure while passing through the conveying system. After passing through a heating zone the moulds may pass through a cooling zone. The rubber may be vulcanized and partly expanded before being placed in the moulds. As shown, conveying apparatus comprises two opposed endless steel bands 10, 13 passing over drums 11, 12, 14 and 15 driven by a belt 18. The moulds 26 are introduced between the bands at the right of Fig. 1 and are carried along through heating and cooling zones and delivered on to a table 41. The lower band 13 is supported under the moulds by a series of rollers 40 mounted in a set of chambers 36 rigidly mounted on the frame, and above the upper band 10 is a similar set of chambers 35 pressed downwards by powerful springs 39 and engaging the band by rollers 40. Each set of chambers is divided into two sections, the right-hand section being steam-heated and the left hand section water-cooled. According to the Provisional Specification, slabs of rubber are fed through the conveyer, the bands themselves constituting the moulds. Specification 358,967 is referred to.