Method and apparatus for producing a plastic profile having a reinforcement

Abstract

In the pultrusion of reinforced plastic profiles in strand form, the strands of the reinforcement are brought together in a positioning device and subsequently embedded in the plastic. The pulling of the strands of the reinforcement through the positioning device leads to an unwanted contraction and uncontrolled positioning of the reinforcement in the plastic profile. The invention envisages forming the positioning device by multiple successive positioning means, of which at least some positioning means can be periodically moved forward in the direction of production and also moved back counter to the direction of production. As a result, there is an alternating tensioning and compression of individual regions of the reinforcement. This makes exact positioning of the reinforcement in the plastic profile possible and prevents contraction of the reinforcement.

What is claimed is: 
     
         1 . An apparatus for producing a plastic profile ( 10 ,  33 ) having a reinforcement ( 11 ), comprising:
 a closed mold ( 23 ,  32 ), completely surrounding the plastic profile ( 10 ,  33 );   at least one positioning device ( 14 ), for the reinforcement ( 11 ) of the plastic profile ( 10 ,  33 ), arranged upstream of the mold ( 23 ,  32 ) in the direction of production ( 13 ) of the plastic profile ( 10 ,  33 ) the positioning device ( 14 ) having multiple successive positioning means ( 15 ,  16 ,  17 ,  18 ); and   at least one of the positioning means ( 15 ,  16 ,  17 ,  18 ) being movable back and forth in relation to at least one other positioning means ( 15 ,  16 ,  17 ,  18 ).   
     
     
         2 . The apparatus as claimed in  claim 1 , wherein each positioning means ( 15 ,  16 ,  17 ,  18 ) is formed like an orifice plate and/or each positioning means ( 15 ,  16 ,  17 ,  18 ) has a passage ( 28 ,  29 ,  30 ,  31 ) for the reinforcement ( 11 ) and the passages ( 28 ,  29 ,  30 ,  31 ) in the positioning means ( 15 ,  16 ,  17 ,  18 ) following one another in the direction of production ( 13 ) become smaller in the direction of production ( 13 ). 
     
     
         3 . The apparatus as claimed in  claim 1 , wherein the positioning means ( 15 ,  16 ,  17 ,  18 ) that is movable back and forth is periodically moved independently of the other positioning means ( 15 ,  16 ,  17 ,  18 ). 
     
     
         4 . The apparatus as claimed in  claim 1 , further comprising at least one pulling device ( 24 ) that can be periodically moved back and forth, wherein the at least one pulling device ( 24 ) follows the mold ( 23 ,  32 ) in the direction of production ( 13 ). 
     
     
         5 . The apparatus as claimed in  claim 3 , wherein the positioning means ( 15 ,  16 ,  17 ,  18 ) that is movable back and forth is periodically moved independently of the other positioning means ( 15 ,  16 ,  17 ,  18 ) by a drive or actuator of its own. 
     
     
         6 . The apparatus as claimed in  claim 4 , wherein the pulling device ( 24 ) has a cooling arrangement and/or consists of multiple gripper parts that can be moved together and apart and in the pressed-together state completely grip around the plastic profile ( 10 ,  33 ) to be produced. 
     
     
         7 . A method for producing a plastic profile ( 10 ,  33 ) having a reinforcement ( 11 ), comprising:
 passing the reinforcement ( 11 ) with plastic ( 12 ) embedding the reinforcement through a mold ( 23 ,  32 ) in the direction of production ( 13 );   forming the mold ( 32 ) with multiple mold portions ( 34 ) following one another in the direction of production ( 13 ) and respectively having a molding passage ( 35 ) corresponding to the cross section of the plastic profile ( 10 ,  33 ) to be produced; and   displacing the mold portions ( 34 ) such that the longitudinal directions ( 36 ) of the molding passages ( 35 ) lie on a longitudinal center axis of the plastic profile ( 10 ) to be produced and/or run tangentially with respect to the longitudinal center axis ( 37 ) of the plastic profile ( 33 ) to be produced to achieve a desired shape of the plastic profile ( 10 ,  33 ).   
     
     
         8 . The method as claimed in  claim 7 , wherein the mold portions ( 34 ) are displaced in such a way that the inclinations of the longitudinal directions ( 36 ) of the molding passages ( 35 ) change. 
     
     
         9 . The method as claimed in  claim 7 , wherein the mold portions ( 34 ) are displaced in such a way that, in the case of plate-like mold portions ( 34 ), points of the molding passages ( 35 ) that lie in the center of the plate lie on the longitudinal center axis ( 37 ) of each plastic profile ( 10 ,  33 ) to be produced. 
     
     
         10 . The method as claimed in  claim 8 , wherein the mold portions ( 34 ) are displaced in such a way that, in the case of plate-like mold portions ( 34 ), points of the molding passages ( 35 ) that lie in the center of the plate lie on the longitudinal center axis ( 37 ) of each plastic profile ( 10 ,  33 ) to be produced. 
     
     
         11 . An apparatus for producing a plastic profile ( 10 ,  33 ) having a reinforcement ( 11 ), comprising a mold ( 32 ) that brings the plastic profile ( 10 ,  33 ) with the reinforcement ( 11 ) lying therein into the desired form, wherein the mold ( 32 ) is formed by multiple mold portions ( 34 ) following one another in a direction of production ( 13 ) and having molding passages ( 35 ) corresponding to the cross section of the plastic profile ( 10 ,  33 ) to be produced, and the size of each molding passage ( 35 ) changes in the longitudinal direction ( 36 ) of the same or in the direction of production ( 13 ) of the plastic profile ( 10 ,  33 ). 
     
     
         12 . The apparatus as claimed in  claim 11 , wherein the mold portions ( 34 ) are formed as mold plates, the molding passages ( 35 ) that extend transversely through the mold plates being smallest approximately in the center of the respective mold plate and increasing in size increasingly toward opposing main surfaces of the molding plates. 
     
     
         13 . The apparatus as claimed in  claim 11 , wherein the mold portions ( 34 ) can be tilted, by the longitudinal direction ( 36 ) of the molding passage ( 35 ) in the respective mold portion ( 34 ), namely the respective mold plate. 
     
     
         14 . The apparatus as claimed in  claim 13 , wherein the respective mold plate is variable in inclination.