METHOD FOR MANUFACTURE OF CROSS-SHAPED MEMBER FOR CONNECTING GREENHOUSE CARCASS PIPES, AND CROSS-SHAPED MEMBER Russian patent published in 2004 - IPC

FIELD: manufacture of greenhouses from hollow plastic pipes. SUBSTANCE: method involves connecting longitudinal and transverse hollow pipes of greenhouse by heating to plastic state of material of longitudinal portion; forming through cut on this portion; introducing into said cut mandrel having diameter at least equal to that of transverse portion, with through cut being formed on longitudinal portion before heating of longitudinal portion to plastic state of material and having length not in the excess of 1.5 the diameter of transverse portion; assembling longitudinal and transverse portions; expanding hollow ends of member to the size of outer diameters of longitudinal and transverse pipes of carcass by heating ends of cross-shaped connecting member in the range of 150-220 C, with following reducing of heating temperature to 100-150 C from edge of said member to its central part at a distance of at least 10 mm; using sharpened end of transverse portion as mandrel to be inserted into longitudinal portion through cut for making greenhouse pipe and carcass connection. Through cut is provided only through one wall of said portion. Cross-shaped pipe and carcass connecting member has cross-shaped joint at longitudinal and transverse portion junction site, said joint having longitudinal and transverse portions. Through cut is formed in mid part of longitudinal portion by means of mandrel for directing through said cut of transverse portion having curvature radius less than 1.8 m. Ends and connections have inner diameters corresponding to outer diameters of greenhouse pipes and carcass to be connected. EFFECT: increased strength of carcass, reduced manufacture costs and increased efficiency.