Method of fabricating bow stick of stringed instrument and bow stick of stringed instrument

Abstract

A method of fabricating a bow stick includes winding a prepreg, in which a fiber is impregnated with a resin, on a mandrel with a diameter gradually decreasing toward a distal end, setting a semi-fabricated product, in which the prepreg is wound on the mandrel, into a mold and molding the semi-fabricated product in a shape corresponding to a cavity formed between the mold and the mandrel by heating and pressurizing the semi-fabricated product in the mold, and taking out the mandrel from a molded product molded in the shape corresponding to the cavity to acquire a long and hollow stick body. When adjusting at least one of a weight distribution, a center of gravity, and a weight of the stick body, the volume of the cavity is changed using the mandrel of which the diameter or the diameter variation is gradually changed in an axis direction.

1 - 4 . (canceled) 
     
     
         5 . A bow stick of a stringed instrument which is used with a stringed instrument and which is formed of fiber-reinforced plastics, the bow stick comprising:
 an elongated hollow stick body having an exposed outer surface and an inner axial hole whose diameter decreases in a stepwise fashion toward a distal end of the stick body, the stick body being formed of fiber-reinforced plastic extending from the inner axial hole to the exposed outer surface of the body, wherein at least one of a weight distribution, a center of gravity, and a weight of the bow stick of the stick body is adjusted by gradually changing the diameter of the axis hole in an axis direction.   
     
     
         6 . A method of fabricating a hollow bow stick body which is used with a stringed instrument, the method being carried out by molding the bow stick body in a cavity formed between a mold and a mandrel, the method comprising:
 selecting a mandrel having a diameter which decreases in a stepwise fashion toward its distal end, the shape of the mandrel being selected to adjust the shape of the cavity and thereby adjust at least one of the weight distribution, center of gravity, and weight of the bow stick body;   winding a prepreg comprising fibers and a plastic resin on the mandrel to form a semi-fabricated product;   placing the semi-fabricated product and the mandrel into the mold;   molding the semi-fabricated product in a shape corresponding to the cavity by heating and pressurizing the semi-fabricated product in the mold to form a molded product; and   removing the mandrel from the molded product to acquire the hollow bow stick body.   
     
     
         7 . The method of  claim 6 , wherein the mandrel is selected from a plurality of mandrels, each of the plurality of mandrels having a different shape designed to change the shape of the cavity when it is placed in the mold. 
     
     
         8 . The method of  claim 6 , wherein the area of the prepreg wound on the mandrel is selected as a function of the shape of the cavity. 
     
     
         9 . An elongated, hollow bow stick which is used with a stringed instrument, the bow stick comprising:
 a hollow stick body formed of fiber-reinforced plastic extending from an inner axial hole of the body to an exposed outer surface of the body, the axial hole having a diameter that decreases in a stepwise fashion toward a distal end of the body such that at least one of a weight distribution, a center of gravity, and weight of the bow stick varies as a function of the diameter of the axial hole in an axis direction.