Article with protective sheath

Abstract

Protective sheaths particularly for fiber reinforced articles comprising a combination of polymeric and metallic material layers, are disclosed. The protective sheaths comprise alternating layers of high and low ductility and are particularly suited for sports articles, such as hockey sticks, lacrosse sticks, baseball/softball bats and golf clubs.

What is claimed is: 
     
         1 . A hockey stick comprising:
 a shaft portion comprising fiber reinforced composite materials, said shaft portion including a grip end and a proximal end, and a blade portion connected to the proximal end of the shaft portion; and   a protective sheath covering at least the proximal end of the shaft portion; said protective sheath representing <50% of the total overall weight of said hockey stick; said protective sheath being composed of a multi-layer structure comprising at least two layers in a depth direction of said protective sheath, each having a thickness between 0.25 and 150 μm; said multi-layer structure comprising a polymer layer having an elongation to failure of >10% in intimate contact with the fiber reinforced composite material of the shaft portion followed by at least one metallic layer having an elongation to failure of ≦10%.   
     
     
         2 . The hockey stick of  claim 1 , wherein said polymer layer has an elongation to failure of ≧15% according to ASTM D412-06a, a thickness of between 50 and 100 μm and comprises an elastomeric material. 
     
     
         3 . The hockey stick of  claim 2 , wherein said elastomeric material comprises at least one material selected from the group consisting of thermoset elastomer, thermoplastic elastomer, thermoset elastomeric urethane, thermoplastic polyurethane, thermoset elastomeric dicyclopentadiene, elastomeric urethane, silicone, rubber, polyisoprene, polybutadiene, polyisobutylene, latex and rubber toughened epoxy compositions. 
     
     
         4 . The hockey stick of  claim 1 , wherein said metallic layer has a thickness of between 20 and 100 μm and a minimum yield strength according to ASTM E8 of 600 MPa. 
     
     
         5 . The hockey stick of  claim 4 , wherein said metallic layer has an average grain size in the range of 2 nm to 5,000 nm, a hardness in the range of 300 Vickers to 1,000 Vickers and includes at least one element selected from the group consisting of Co, Cu, Fe, Ni and P. 
     
     
         6 . The hockey stick of  claim 5 , wherein said metallic layer has an average grain size between 2 and 100 nm. 
     
     
         7 . The hockey stick of  claim 1  wherein said protective sheath comprises at least three layers alternating in ductility between ≦10% and >10%. 
     
     
         8 . The hockey stick of  claim 1 , wherein at least outer edges of the blade portion are covered by said protective sheath. 
     
     
         9 . A hockey stick comprising:
 a shaft portion including a grip end and a proximal end and a blade portion connected to the proximal end of the shaft portion, each of the shaft portion and blade portion comprising fiber reinforced composite materials; and   a protective sheath covering at least outer edges of the blade portion and extending beyond at least an edge of the proximal end of the shaft portion up to 50% of an outer length of the shaft portion; said protective sheath having a surface roughness R a  in the range of 2.5 to 15 μm and representing between 3 and 50% of the total overall weight of the hockey stick; said protective sheath being composed of a multi-layer structure containing at least four layers each having a thickness between 0.25 and 150 μm; said multi-layer structure comprising a polymer first layer having an elongation to failure of >10% in intimate contact with the fiber reinforced composite material of the hockey stick followed by a metallic second layer having an elongation to failure of ≦10%; followed by a metallic third layer having an elongation to failure of >10%; followed by a metallic fourth layer having an elongation to failure of ≦10% and a minimum yield strength according to ASTM E8 of 600 MPa.   
     
     
         10 . The hockey stick of  claim 9 , wherein said polymer first layer comprises an elastomeric material having an elongation to failure of >10% and a thickness of between 50 and 100 μm, said metallic second layer having a thickness of between 0.25 and 5 μm, said metallic third layer having an elongation to failure of ≧15% and a thickness of between 0.5 and 25 μm;
 and said metallic fourth layer having a thickness of between 20 and 100 μm. 
 
     
     
         11 . The hockey stick of  claim 10 , wherein said elastomeric material layer comprises at least one material selected from the group consisting of thermoset elastomer, thermoplastic elastomer, thermoset elastomeric urethane, thermoplastic polyurethane, thermoset elastomeric dicyclopentadiene, elastomeric urethane, silicone, rubber, polyisoprene, polybutadiene, polyisobutylene, latex and rubber toughened epoxy compositions. 
     
     
         12 . The hockey stick of  claim 9 , wherein said metallic second layer of said protective sheath comprises an amorphous Ni alloy. 
     
     
         13 . The hockey stick of  claim 9 , wherein said metallic third layer of said protective sheath comprises at least one element selected from the group consisting of Ag, Co, Cu, Fe, Ni and P. 
     
     
         14 . The hockey stick of  claim 9 , wherein said metallic fourth layer of said protective sheath comprises at least one element selected from the group consisting of Co, Cu, Fe, Ni and P. 
     
     
         15 . The hockey stick of  claim 14 , wherein said metallic fourth layer comprises at least one element selected from the group of Co, Cu, Fe, Ni and P having an average grain size that is in the range of 2 nm to 5,000 nm, a yield strength in the range of 200 MPa to 2,750 MPa, and a hardness in the range of 300 Vickers to 1,000 Vickers. 
     
     
         16 . The hockey stick of  claim 15 , wherein said metallic fourth layer has an average grain size between 2 and 100 nm. 
     
     
         17 . The hockey stick of  claim 9 , wherein said protective sheath comprises at least five layers, wherein said fifth layer comprises a polymer having an elongation to failure of ≧15%. 
     
     
         18 . The hockey stick of  claim 9 , wherein said protective sheath has a weight of between 20 and 50 g. 
     
     
         19 . The hockey stick of  claim 9 , wherein said protective sheath fully encapsulates at least one of the blade portion and a slash zone defined by the proximal end of the shaft portion. 
     
     
         20 . The hockey stick of  claim 9 , wherein said protective sheath has a total thickness in the range of 50 to 350 μm. 
     
     
         21 . A hockey stick comprising:
 a shaft portion including a grip end and a proximal end, and a blade portion connected to the proximal end of the shaft portion, each of the shaft portion and blade portion comprising fiber reinforced composite materials; and   a protective sheath covering at least outer edges of the blade portion and extending beyond at least an edge of the proximal end of the shaft portion up to 50% of an outer length of the shaft portion; said protective sheath having a surface roughness R a  in the range of 2.5 to 15 μm and representing between 3 and 50% of the total overall weight of the hockey stick; said protective sheath being composed of a multi-layer structure containing at least four layers each having a thickness between 0.25 and 150 μm; said multi-layer structure comprising alternating layers having an elongation to failure of ≦10% and layers having an elongation to failure of >10%; said multi-layer structure comprising a polymer layer having an elongation to failure of >10% in intimate contact with the fiber reinforced composite material of the hockey stick and at least one metallic layer having an elongation to failure of ≦10% selected from the group of Co, Cu, Fe and Ni having an average grain size that is in the range of 2 nm to 5,000 nm, a yield strength in the range of 200 MPa to 2,750 MPa, and a hardness in the range of 300 Vickers to 1,000 Vickers.   
     
     
         22 . The hockey stick of  claim 20 , wherein said protective sheath has a total thickness in the range of 50 to 350 μm. 
     
     
         23 . A hockey stick comprising:
 a shaft portion connected to a blade portion, said shaft portion including a grip end and a proximal end, said shaft portion having a top face and a front face, said top face being narrower than said front face and oriented perpendicular to said front face; and   a protective sheath comprising at least one metallic layer covering at least part of an outer length of said shaft portion;   wherein said shaft portion having the protective sheath has a loss of peak load performance measured on the front face of less than 30% after being subjected to an impact force of 15 J on the top face.   
     
     
         24 . The hockey stick of  claim 23 , wherein said shaft portion having said protective sheath after impact has an average peak load value exceeding an average peak load value on the shaft portion devoid of said protective sheath before impact. 
     
     
         25 . The hockey stick of  claim 23 , wherein said shaft portion having said protective sheath provided at least a 30% increase in load to failure after being subjected to three point bend tests over approximately 1 m of said shaft portion. 
     
     
         26 . The hockey stick of  claim 23 , wherein said shaft portion having said protective sheath provided at least a 16.5% increase in deflection to failure after being subjected to three point bend tests over approximately 1 m of said shaft portion. 
     
     
         27 . An article comprising:
 a shaft portion comprising fiber reinforced composite materials, said shaft portion defining a grip end and a proximal end, said shaft portion comprising a top face and a front face, said top face being oriented perpendicular to said front face; and   a protective sheath comprising at least one metallic layer covering at least part of an outer length of said shaft portion;   wherein said shaft portion having said protective sheath after a 15 J impact on the top face has an average peak load value on the front face exceeding an average peak load value on the shaft portion devoid of said protective sheath and not subjected to the 15 J impact.   
     
     
         28 . The article of  claim 27 , wherein said protective sheath is composed of a multi-layer structure comprising at least two layers each having a thickness between 0.25 and 150 μm; said multi-layer structure comprising a polymer layer having an elongation to failure of >10% and at least one metallic layer having an elongation to failure of ≦10%. 
     
     
         29 . The article of  claim 27 , wherein said article is selected from the group consisting of a hockey stick, a lacrosse stick, a tennis racquet, a squash racquet, a racquetball racquet and a badminton racquet, and a golf shaft.