Formwork for cylindrical columns

Abstract

It is applicable to a formwork made from a tubular body in plasticised wood, rigid plastic or the like, conveniently stabilised by means of an outer envelope made of a glass fiber mesh rolled up helicoidally, with or without the intercalation of a second tubular body made of expanded polystyrene; the improvements of the invention consist in obtaining an inner tubular body in plastic or wood made of a single plate ( 7 ) which width coincides with the perimeter of the formwork to be obtained, having said plate ( 7 ) a continuous internal side ( 8 ) and with an external side ( 10 ) wherein a plurality of longitudinal cuts ( 9 ) are established, evenly distributed, affecting mainly the thickness of said plate, defining weakened zones ( 11 ) allowing an easy deformation of said plate ( 7 ), which is initially flat, in order to convert it into a cylindrical and tubular element.

1 . Formwork for cylindrical columns, of the type including an annular body made of rigid plates, in plasticised wood, rigid plastic or the like, conveniently fixed in such a way that said annular body adopts, in use, the section corresponding to the column to be obtained, 
 characterized in that said rigid plates constituting the annular body ( 1 ) are made of laminates ( 2 ) having a reduced width, more reduced when greater is the degree of proximity of the formwork to the perfect cylinder, said laminates ( 2 ) being fixed to each other to configure said annular body with the help of an external envelope ( 3 ) made of a glass fibre mesh rolled up helicoidally on said annular body, while said annular body ( 1 ) receives innerly a self-adhesive film ( 4 ) covering continuously the whole inner surface of all the laminates ( 2 ) in order to provide the formwork with an appropriate tightness.    
     
     
         2  Formwork for cylindrical columns according to  claim 1 , characterized in that optionally, in order to provide the formwork with a complete formal stability when handling the same in an empty state, a plurality of belts or bands ( 5 ) are established on the envelope ( 3 ) made of glass fibre mesh, conveniently distributed along the formwork and made of a rigid material such as, for instance, metal or expanded polystyrene.  
     
     
         3 . Formwork for cylindrical columns according to  claim 1 , characterized in that optionally, in order to provide the formwork with a complete formal stability when handling the same in an empty state, a tubular body ( 6 ) made of expanded polystyrene, acting as a stiffening element, is established between the annular body ( 1 ) made of rigid laminates ( 2 ) and the envelope ( 3 ) made of glass mesh.  
     
     
         4 . Formwork for cylindrical columns according to  claim 1 , characterized in that said annular body made of plasticised wood, rigid plastic or the like, is formed by a plate ( 7 ), initially flat, having a length according to the height of the column to be obtained and a width according with the diameter of said column, said plate ( 7 ) being affected by a plurality of longitudinal cuts or slots ( 9 ) open towards their outer side ( 10 ) and defining in said plate ( 7 ) some lines ( 11 ) remarkably weakened, allowing the deformation of said plate in order to change its original flat configuration into a cylindrical, tubular configuration, according to the column to be obtained.  
     
     
         5 . Formwork for cylindrical columns according to  claim 4 , characterized in said plate is helped by two end rigid rings ( 12 ), having a “U” section, defining each one of them an annular groove ( 13 ) which receives in its interior the corresponding end of the plate ( 7 ), by means of which the perfect cylindrical shaping of said plate ( 7 ), and consequently of the formwork as a whole, is assured.  
     
     
         6 . Formwork for cylindrical columns according to  claim 5 , characterized in that the lateral branches of the rings ( 12 ) having a “U” profile are asymmetric, in order to facilitate the positioning inside the groove ( 13 ) of the corresponding end of plate ( 7 ) and hence the cylindrical shaping of said plate.  
     
     
         7 . Formwork for cylindrical columns according to any of the preceding claims, characterized in that it is included, as an outer stiffening envelope ( 3 ), a self-adhesive tape having a plurality of glass fibre threads ( 17 ), disposed longitudinally and evenly distributed, in such a way that said band is fixed to the rest of the structure of the formwork due to its self-adhesive condition, with an helicoidal path and preferably with a partial overlap of the same, in such a form that the fibres are in a substantially transversal position with respect to the imaginary axis of the formwork.  
     
     
         8 . Formwork for columns according to any preceding claim, characterized in that said self-adhesive tape ( 14 ) consists in a support ( 15 ) made of a sheet of paper or the like, including in one of its sides a layer ( 16 ) of self-adhesive glue wherein the glass fibre threads ( 17 ) are embedded.