Apparatus for manufacturing composite tubular articles

Abstract

A frame, a drive mechanism for rotating a mandrel, at least two spindles mounted to the frame, a tensioner, and a belt extending between the first and second spindles may be used to roll pre-preg strips or similar sheets of composite materials around the mandrel. The belt travels over the spindles, and the spindles guide the belt through changes in its direction of travel. The mandrel is mounted in the drive mechanism in contact with the belt, which changes its direction of travel around the mandrel. The lower surface of the belt bears against upper portions of the spindles, and the mandrel contacts the upper surface of the belt. As the drive mechanism rotates the mandrel, pre-preg sheets are fed between the mandrel and the belt and are thereby wrapped around the mandrel. The belt presses the pre-preg sheets against the mandrel. The wrapped mandrel may then be removed from the apparatus and cured in any suitable manner known in the art to produce a composite tubular article.

What is claimed is:  
     
       1. An apparatus for wrapping material around a mandrel, said apparatus comprising: 
       a frame;  
       first and second spindles connected to said frame;  
       a belt in contact with a portion of each of said first and second spindles, said belt movable in a belt movement direction, said belt having two ends and including a resilient member connecting said ends; and  
       a drive mechanism having a rotatable driven portion with an axis of rotation extendable perpendicular to said belt movement direction, said mandrel mountable on said driven portion said belt and said resilient member movable in said belt movement direction as a result of actuation of said driven mechanism.  
     
     
       2. The apparatus claimed in  claim 1 , wherein said belt has an upper surface and a lower surface, portions of said lower surface of said belt are in contact with portions of each of said first and second spindles when a portion of said upper surface of said belt is in contact with said mandrel. 
     
     
       3. The apparatus claimed in  claim 1 , wherein said first and second spindles are rotatably mounted on said frame. 
     
     
       4. The apparatus claimed in  claim 1 , wherein a plurality of elastic cords connect said ends of said belt. 
     
     
       5. The apparatus claimed in  claim 4 , further comprising a third spindle, wherein said belt and elastic cords extend around said first, second and third spindles. 
     
     
       6. The apparatus claimed in  claim 1 , further comprising a third spindle movably mounted to said frame, wherein said third spindle is movable toward and away from said first and second spindles. 
     
     
       7. The apparatus claimed in  claim 6 , further comprising an actuator for selectably moving said third spindle toward and away from said first and second spindles. 
     
     
       8. The apparatus claimed in  claim 7 , wherein said actuator is pneumatically operated. 
     
     
       9. The apparatus claimed in  claim 8 , wherein a plurality of elastic cords connect said ends of said belt. 
     
     
       10. The apparatus claimed in  claim 9 , further comprising a third spindle, wherein said belt and elastic cords extend around said first, second and third spindles. 
     
     
       11. The apparatus claimed in  claim 1 , wherein at least one of said first and second spindles is movably mounted to said frame and movable toward and apart from the other of said spindles. 
     
     
       12. The apparatus claimed in  claim 11 , wherein said first and second spindles are rotatably mounted on said frame. 
     
     
       13. The apparatus claimed in  claim 11 , further comprising an actuator for selectably moving at least one of said first and second spindles toward and apart from the other of said spindles. 
     
     
       14. A continuous loop belt for use in a machine for wrapping material around a mandrel, the belt comprising: 
         a pliable sheet panel of coarse woven plastic fibers, the panel having sufficient pliability to conform to changes in mandrel diameter including multiple tapers or contours or non - uniform tapers in order to press pre - preg sheets against the tapered mandrel along its entire length, the panel having ends adapted to be connected together, a lower surface adapted to engage support spindles and an upper surface adapted to engage the mandrel, wherein said panel is formed at least partly of closely spaced, relatively thin, plastic fibers interwoven with a weft comprising a yarn having lesser number of relatively thicker stronger plastic fibers with the yarn strands spaced relatively farther apart; and    
         elastic tensioning means connecting the ends of said panel together to form a continuous loop for passing around the support spindles and partially around the mandrel and enabling the belt to stretch enabling portions of the belt to travel different distances to conform to a taper on the mandrel to form composite articles having multiple tapers or contours or non - uniform tapers.   
     
     
       15. A belt according to  claim 14 , wherein said panel upper surface is sufficiently slippery to resist adherence of pre- preg; and said panel upper surface providing sufficient friction to be driven by said mandrel.   
     
     
       16. A belt according to  claim 14 , wherein said elastic tensioning means comprises a plurality of elastic cords. 
     
     
       17. A method of making a belt for use in a machine for wrapping material around a mandrel, comprising: 
         providing a generally rectangular pliable sheet panel of coarse woven plastic fibers, the panel having sufficient pliability to conform to changes in mandrel diameter including multiple tapers or contours or non - uniform tapers in order to press pre - preg sheets against the tapered mandrel along its entire length, the panel having ends adapted to be connected together, a lower surface adapted to engage support spindles and an upper surface adapted to engage the mandrel; providing elastic tensioning means adapted to connect the ends of the panel together, wherein the step of providing a generally rectangular pliable sheet panel comprises providing the panel formed at least partly of a woven fabric of closely spaced, relatively thin, plastic fibers interwoven with a weft comprising a yarn having lesser number of relatively thicker stronger plastic fibers with the yarn strands spaced relatively farther apart; and    
         connecting the ends of the panel together by connecting the tensioning means to the ends of the panel thereby forming the belt into a continuous loop for mounting on the spindles, the elastic tensioning means enabling portions of the belt to travel different distances to conform to a taper on the mandrel to form composite articles having multiple tapers or contours or non - uniform tapers on the mandrel.   
     
     
       18. A method according to  claim 17 , wherein the step of providing elastic tensioning means comprises providing a plurality of elastic cords. 
     
     
       19. A method according to  claim 17 , wherein: said step of providing said panel includes providing said panel upper surface is sufficiently slippery to resist adherence of pre- preg; and said panel upper surface having sufficient friction to be driven by said mandrel.