Seat element moulded from expandable and retriculable polyolefin material
A manufacturing method of a seat element ( 1; 101 ) is disclosed, comprising a body ( 2 ) obtained from moulding polyolefin plastic materials of expandable and reticulable type, and a template ( 3; 103 ) made of rigid material, which is coupled with the body ( 2 ) when it is still hot, in such a way to control the shrinking of the material of the body during cooling.
1 . Manufacturing method of a seat element ( 1 ; 101 ) comprising the following phases:
injection into a mould of expandable and reticulable polyolefin material,
reticulation and expansion of said polyolefin material inside the mould, in such a way to obtain a body ( 2 ) having the shape of the mould,
release of the body ( 2 ) from the mould due to expansion,
prosecution of expansion of the body ( 2 ) outside the mould until expansion is completed, and
coupling of said body ( 2 ) with a template ( 3 ; 103 ) made of rigid material, when the body ( 2 ) has completed expansion and before the material of the body shrinks during cooling, and
cooling and thermoretraction of the body ( 2 ) controlled by the template ( 3 ; 103 ), in such a way that the body complies with the original specifications of the template, wherein the template ( 3 ) acts as stiffening element of the body ( 2 ), and fixing means ( 33 ; 133 ) are provided on the template ( 3 ; 103 ) and the template is fixed to a support frame ( 4 ; 104 ), so that the template ( 3 ) acts as fixing means with the frame ( 4 ; 104 ) to anchor the seat ( 1 ) to the frame ( 4 ; 104 ).
2 . Method as claimed in claim 1 , wherein the cavity of mould is smaller than seat to be obtained.
3 . Method as claimed in claim 2 , wherein the cavity of mould is 50% smaller than seat to be obtained.
4 . Method as claimed in claim 1 , wherein the mould is shaped in such a way that the body ( 2 ) is provided on the back surface with a recessed seat ( 21 ) with slightly smaller area than the surface of the body and said template ( 3 ; 103 ) is inserted in the recessed seat.
5 . Method as claimed in claim 4 , wherein the mould is shaped in such a way that the body ( 2 ) has a perimeter frame ( 20 ) that defines the recessed seat ( 21 ), housings in undercut ( 22 ) are obtained in the internal borders of the perimeter frame ( 20 ), and the borders of the template ( 3 ; 103 ) are inserted in the housings in undercut ( 22 ).
6 . Method as claimed in claim 1 , wherein the template is fixed to the frame with screw means ( 40 ) of the frame that cross the through holes ( 33 ) obtained on the template.
7 . Method as claimed in claim 1 , wherein the template is fixed to the frame with screw means ( 133 ) of the template that are inserted in holes ( 140 ) of the frame.