Dart

Abstract

A dart includes, in sequence from a distal side to a proximal side thereof, a tip, a barrel, and a shaft. The shaft has a diameter which gradually decreases from a distal side toward a proximal side thereof. Three flights are attached and fixed to the proximal side of the shaft at equiangular positions around a center axis of the shaft, and proximal sides of the flights protrude from the shaft to be connected to one another. The shaft includes grooves, each of which is formed between the flights adjacent to each other in a circumferential direction of the shaft, and each of the grooves has an inner width which gradually increases from a side of the flights toward an axial direction center part of the shaft and which gradually decreases from the axial direction center part of the shaft toward a side of the barrel.

1 . A dart comprising, in sequence from a distal side to a proximal side of the dart, a tip, a barrel, and a shaft, wherein:
 the shaft has a diameter which gradually decreases from a distal side toward a proximal side of the shaft, three flights are attached and fixed to the proximal side of the shaft at equiangular positions around a center axis of the shaft, and proximal sides of the flights protrude from the shaft to be connected to one another; and   the shaft includes grooves, each of which is formed between the flights adjacent to each other in a circumferential direction of the shaft, and each of the grooves has an inner width which gradually increases from a side of the flights toward an axial direction center part of the shaft, and which gradually decreases from the axial direction center part of the shaft toward a side of the barrel.   
     
     
         2 . The dart according to  claim 1 , wherein a depth of each of the grooves gradually becomes deeper from the side of the flights toward the axial direction center part of the shaft and gradually becomes shallower from the axial direction center part of the shaft toward the side of the barrel. 
     
     
         3 . The dart according to  claim 1 , wherein the grooves include three grooves, and the three grooves have a same shape and are formed at the equiangular positions around the center axis of the shaft. 
     
     
         4 . The dart according to  claim 3 , wherein the shaft is attachable to and detachable from the barrel. 
     
     
         5 . The dart according to  claim 2 , wherein the grooves include three grooves, and the three grooves have a same shape and are formed at the equiangular positions around the center axis of the shaft. 
     
     
         6 . The dart according to  claim 5 , wherein the shaft is attachable to and detachable from the barrel.