Propeller for driving watercraft

Abstract

A propeller for driving watercraft, having propeller blades and a metal hub for connection to a ship's shaft and a method for the production thereof are described. The propeller blades are manufactured from polyamide 12 C or a composite material made of polyamide 12 C with long and/or short fiber cores. The propeller blades or components of the propeller blades are mounted on the hub, or the propeller as a whole is made of polyamide 12 C or a composite material made of polyamide 12 C with long and/or short fiber cores and the hub encapsulated with PA 12 C. This can achieve an improvement in thrust performance and the reduction in acoustic signature as compared to metal propellers.

1 . Propeller for driving watercraft, having propeller blades and a metal hub for connection to a ship's shaft, wherein said propeller blades are manufactured from polyamide 12 C or a composite made of polyamide 12 C with long and/or short fiber cores and said propeller blades or components of said propeller blades are mounted on said hub, or that said propeller as a whole is made of polyamide 12 C or a composite material made of polyamide 12 C with long and/or or short fiber cores and said hub encapsulated with PA 12 C. 
     
     
         2 . Propeller according to  claim 1 , wherein said individual propeller blades or pairs of blades formed therefrom are fastened by way of metal tie anchors embedded in said propellers and their being clamped in the collar of said hub and a Böttcher ring mounted on said hub. 
     
     
         3 . Propeller according to  claim 2 , wherein openings for said metal tie anchors are formed in said Böttcher ring and said tie anchors are clamped against said Böttcher ring by way of nuts. 
     
     
         4 . Propeller according to  claim 3 , wherein said propeller blades comprise bores for said tie anchors and one or more respective pockets are formed over the length of said bores to reduce material stresses. 
     
     
         5 . Propeller according to  claim 3 , furthermore with a cover attached to the end of said hub to cover said nuts/screw connections and to optimize flow in the wake of the ship's shaft and/or hub. 
     
     
         6 . Propeller according to  claim 1 , furthermore with structural elements for transmitting forces and torques from said hub into said propeller blades, wherein said structural elements, in the shape of rods, profiles, metal structures, or inserts, are attached to said hub by way of a force-fit, positive-fit, and/or substance-fit connection and are completely encapsulated with polyamide 12 C. 
     
     
         7 . Propeller according to  claim 6 , wherein said hub has a surface prepared by etching, sandblasting, knurling, and/or applying finishing for being encapsulated with PA 12 C. 
     
     
         8 . Propeller according to  claim 1 , wherein one or several propeller blades has a surface structure similar to shark skin. 
     
     
         9 . Method for the manufacture of a propeller for driving watercraft, having propeller blades and a metal hub for connection to a ship's shaft, wherein said propeller blades are manufactured from polyamide 12 C or a composite material made of polyamide 12 C with long and/or short fiber cores and said propeller blades or components of said propeller blades are mounted on said hub, or that said propeller as a whole is manufactured from polyamide 12 C or a composite material made of polyamide 12 C with long and/or or short fiber cores by shaping all propeller blades in one casting process while simultaneously enclosing said metal hub of said propeller. 
     
     
         10 . Method according to  claim 9 , wherein metal tie anchors are inserted into said propeller blades for force and torque transmission by heating said polyamide 12 C and pressing in said tie anchor at room temperature and/or by cooling said tie anchor and pressing in at room temperature. 
     
     
         11 . Method according to  claim 9  while shaping all propeller blades in one casting process while simultaneously enclosing said hub prepared for this purpose, wherein structural elements for introducing force from said hub into said individual propeller blades are fastened to said hub and completely enclosed by PA 12 C during the casting process. 
     
     
         12 . Method according to  claim 11 , wherein said hub is prepared at the surface towards the PA 12 C by etching, sandblasting, knurling, and/or applying finishing for being encapsulated. 
     
     
         13 . Method according to  claim 9 , wherein said propeller formed by casting and cured is machined to produce its final contour. 
     
     
         14 . Method according to  claim 9 , wherein, for designing said surface of one or all propellers or parts of the surface, a surface structure similar to that of a shark skin is cast by shaping the mold and/or incorporating granular materials into the surface as part of the casting process.