Process and plant for continuous manufacture of latex foam articles

Abstract

Process for continuous manufacture of latex foam rest articles ( 2, 38 ) such as mattresses, cushions and the like comprising a part ( 18 ) able to participate to the manufacture steps and to remain embedded in the article with consequent improvements of final performances. A flexible perforated band, preferably a flat polymeric material net ( 18 ) with longitudinal and cross reinforcement members ( 19 ), is placed over a foam laying surface ( 3 ) provided with protuberances ( 7 ) and in continuous advancement between a foam laying station ( 4 ) and an unlimited length article extraction station ( 5 ). The latex foam passes through net holes ( 20 ) forming an upper portion ( 24 ) and a lower portion ( 23 ) relative to said net. The net continuously opposes contraction forces and weight force exerted from upper portion on lower portion. The unlimited length article is subjected to successive cross cuts originating rest articles wherein a foam embedded net is arranged on ends of recesses originated by the protuberances.

1 - 8 . (canceled) 
     
     
         9 . A plant for the continuous manufacture of an unlimited length latex foam block to be subdivided in a plurality of articles by cuts transversely to said unlimited length, said plant comprising:
 a structural part comprising a laying surface for continuously advancing along a predetermined direction between a first latex foam laying station and a second block extraction station,   a plurality of protuberances cantilevering from said laying surface to a plane parallel to said laying surface, a latex foam gelation device,   a vulcanisation device before said second extraction station,   a drying device,   an auxiliary part in continuous advancement capable of participating to the operation steps and remaining embedded in said article for a predetermined length after said block cutting, said auxiliary part comprising a flexible band substantially flat of unlimited length and provided with a plurality of through openings, said band being arranged continuously over said protuberances and associated to said protuberances by the latex foam passing through said openings.   
     
     
         10 . Plant according to  claim 9 , wherein said band is in polymeric material. 
     
     
         11 . Plant according to  claim 9 , wherein said band embedded in said continuously advancing foam forms means contrasting the contraction forces present on said block. 
     
     
         12 . Plant according to  claim 9 , wherein said band has a laminar structure provided with holes. 
     
     
         13 . Plant according to  claim 9 , wherein said band is made up from a plastic net comprising a plurality of longitudinal members directed transversely to each other to form a plurality of meshes. 
     
     
         14 . Plant according to  claim 9 , comprising a coil with a collection seat of said band loops having a cylindrical surface with diameter from 5 to 100 cm. 
     
     
         15 . Latex foam block comprising a plurality of lower recesses extending up to a predetermined height “s 1 ”, incorporating along the plane delimiting the recesses upper ends a polymeric material flexible band provided with through openings. 
     
     
         16 . Latex foam block according to  claim 15 , wherein the latex foam density is from 40 to 270 grams/litre. 
     
     
         17 . Latex foam block according to  claim 15 , wherein said band is in plastic material. 
     
     
         18 . Latex foam block according to  claim 15 , wherein said band comprises a plurality of through openings arranged according to two directions perpendicular to each other in a same plane, said openings having a pitch from 1 to 4 cm. 
     
     
         19 . The plant according to  claim 9 , wherein said block is continuous and the latex foam of the latex foam block mainly comprising open cells. 
     
     
         20 . Latex foam block according to  claim 15 , wherein said block is continuous and the latex foam of the latex foam block mainly comprising open cells. 
     
     
         21 . A plant for the continuous manufacture of an unlimited length latex foam block to be subdivided in a plurality of mattresses by cuts transversely to said unlimited length, comprising:
 means for advancing along a predetermined longitudinal direction a laying surface provided with protuberances, having tapered ends to form recesses in said mattresses, said laying surface advancing between a first and a second station,   means for laying in said first station a latex foam mixture on said laying surface in continuous advancement, and   further comprising:   a) means for providing proximate to said first station a substantially flat flexible band of unlimited length and provided with a plurality of through openings;   b) means for laying said flexible band on said laying surface protuberances;   c) means for advancing continuously said flexible band with that laying surface;   d) means for introducing said mixture in said band openings, downwardly passing a portion of the mixture through the openings;   e) means for forming from the mixture a continuous latex foam layer comprising a lower portion and an upper portion respectively below and above said band, the latex foam mainly comprising open cells;   f) means for pressing with said upper portion weight said band against said laying surface protuberances;   g) means for gelating, vulcanising, drying said foam layer incorporating said band to form said foam block of continuous latex foam incorporating said band;   h) means for cutting said foam block of continuous latex foam incorporating said band with consecutive cross cuts at a predetermined distance from each other.