Turbine-tip arrowhead

Abstract

The present invention is a turbine tip arrowhead, used either strictly as a field point or as the forwardmost tip in conjunction with any prior art broadhead assembly. The key feature of this turbine tip is the geometry, which includes a tapered tip and a plurality of helical rifles, consisting of either grooves or ridges, beginning at the tip of the field point and spiraling back towards the aft end. All rifles spiral in the same rotational direction giving the appearance of a turbine. This turbine tip design provides excellent rotation of the arrow shaft during flight without producing a large amount of aerodynamic drag. The invention is compatible with all contemporary arrow shafts and with all contemporary broadhead assemblies. A novel broadhead assembly utilizing the turbine tip and deployable blades to produce axial rotation is also described.

1 . An arrowhead comprising: 
 a body;    a plurality of helical rifles integral to said body; and    an attachment means used to mount said arrowhead on a contemporary arrow shaft;    wherein a portion of said body tapers to a point at one end;    wherein said rifles begin at said point and spiral down the longitudinal axis of said body; and    wherein all said rifles spiral in the same rotational direction giving the appearance of a turbine.    
   
   
       2 . An arrowhead according to  claim 1 , 
 wherein said rifles are close together around said body so that they contact each other down their entire helical length.    
   
   
       3 . An arrowhead according to  claim 1 , 
 wherein there are between about three and about ten said rifles.    
   
   
       4 . An arrowhead according to  claim 1 , 
 wherein there are eight said rifles.    
   
   
       5 . An arrowhead according to  claim 1 , 
 wherein said rifles are defined as grooves if the maximum diameter of the rifled portion of said body does not exceed the nominal maximum diameter of said body, and    wherein said rifles are defined as ridges if the maximum diameter of the rifled portion of said body exceeds the nominal maximum diameter of said body.    
   
   
       6 . An arrowhead according to  claim 1 , 
 wherein said rifles terminate partially down a portion of the axial length of said body.    
   
   
       7 . An arrowhead according to  claim 1 , 
 wherein said attachment means comprises a threaded post.    
   
   
       8 . An arrowhead according to  claim 1 , 
 wherein said body is cylindrical.    
   
   
       9 . A broadhead arrowhead comprising: 
 a ferrule,    at least one blade coupled to said ferrule,    an attachment means used to mount said broadhead on an arrow shaft, and    a tip;    wherein said tip further includes a plurality of helical rifles integral to said tip;    wherein said tip further includes an attachment means used to mount said tip on said broadhead;    wherein a portion of said tip tapers to a point at one end;    wherein said rifles begin at said point and spiral down the longitudinal axis of said tip; and    wherein all said rifles spiral in the same rotational direction giving the appearance of a turbine.    
   
   
       10 . An arrowhead according to  claim 9 , 
 wherein said rifles are close together around said body so that they contact each other down their entire helical length.    
   
   
       11 . An arrowhead according to  claim 9 , 
 wherein there are between about three and about ten said rifles.    
   
   
       12 . An arrowhead according to  claim 9 , 
 wherein there are eight said rifles.    
   
   
       13 . An arrowhead according to  claim 9 , 
 wherein said rifles are defined as grooves if the maximum diameter of the rifled portion of said body does not exceed the nominal maximum diameter of said body, and    wherein said rifles are defined as ridges if the maximum diameter of the rifled portion of said body exceeds the nominal maximum diameter of said body.    
   
   
       14 . An arrowhead according to  claim 9 , 
 wherein said rifles terminate partially down a portion of the axial length of said body.    
   
   
       15 . An arrow comprising: 
 an arrowhead body;    a plurality of helical rifles integral to said body; and    an attachment means used to mount said body on a contemporary arrow shaft;    wherein a portion of said body tapers to a point at one end;    wherein said rifles begin at said point and spiral down the longitudinal axis of said body; and    wherein all said rifles spiral in the same rotational direction giving the appearance of a turbine; and    a shaft devoid of fletching, said arrowhead being secured to one end region of said shaft.    
   
   
       16 . A broadhead arrow comprising: 
 a ferrule,    at least one blade coupled to said ferrule,    an attachment means used to mount said broadhead on an arrow shaft, and    a tip;    wherein said tip further includes a plurality of helical rifles integral to said tip;    wherein said tip further includes an attachment means used to mount said tip on said broadhead;    wherein a portion of said tip tapers to a point at one end;    wherein said rifles begin at said point and spiral down the longitudinal axis of said tip; and    wherein all said rifles spiral in the same rotational direction giving the appearance of a turbine; and    a shaft devoid of fletching, said arrowhead being secured to one end region of said shaft.    
   
   
       17 . A broadhead arrowhead comprising: 
 a ferrule having a first end and a second end;    at least one deployable blade assembly, each coupled to said ferrule by a pivot shaft;    a mounting means for mounting said arrowhead to an arrow shaft; and    a tip;    wherein said tip further includes a plurality of helical rifles integral to said tip;    wherein said tip further includes an attachment means used to mount said tip on said broadhead;    wherein a portion of said tip tapers to a point at one end;    wherein said rifles begin at said point and spiral down the longitudinal axis of said tip; and    wherein all said rifles spiral in the same rotational direction giving the appearance of a turbine;    wherein said deployable blade assembly further comprises a semi-circular fourth blade portion integral to a first end of an elongated third blade portion, and a flag-shaped fifth blade portion integral to a second end of said third blade portion;    wherein said ferrule further comprises a deployable blade slot cut into the side of said ferrule for each said deployable blade assembly;    wherein said fourth blade portion fits into said deployable blade slot;    wherein said deployable blade slot is substantially coplanar with a longitudinal axis of said ferrule and is of a depth and geometry that permits each said deployable blade to rotate freely about said pivot shaft;    wherein said ferrule further comprises a cylindrical cavity that begins at the leading face of said first end of said ferrule and continues down a longitudinal axis of said ferrule to a depth approximately equal to the location of said at least one pivot shaft;    wherein said cavity contains a trigger, comprising a solid cylinder such that said trigger can slide freely within said cavity;    wherein said trigger includes a trailing surface that interfaces with a ledge on each said fourth blade portion when said deployable blades are in the closed position; and    wherein said cavity further contains a mechanical tensioner located between the leading face of said trigger and the trailing edge of said main blade such that said trailing edge of said main blade compresses said tensioner, which in turn urges said trigger in the aft direction.    
   
   
       18 . An arrowhead according to  claim 17 , 
 wherein both said third blade portion and said fourth blade portion are disposed in a plane at least substantially parallel to a longitudinal axis of said ferrule and said fifth blade portion extends at an angle to the plane of said third blade portion; and    said fifth blade portion is preferably continuously curved, wherein said deployable blade assembly has an airfoil-type shape.    
   
   
       19 . An arrowhead according to  claim 18 , 
 further comprising a plurality of said deployable blade assemblies disposed substantially symmetrically around the longitudinal axis of said ferrule.    
   
   
       20 . An arrowhead according to  claim 19 , wherein said fifth blade portion has a leading edge region disposed at an angle to said ferrule.  
   
   
       21 . An arrowhead according to  claim 20 , wherein said leading edge region is disposed at an angle to said ferrule in the range of about 5 degrees and about 45 degrees.  
   
   
       22 . An arrowhead according to  claim 19 , wherein said fifth blade portion has a length of between 20% and 50% of the overall length of said deployable blade assembly.  
   
   
       23 . An arrowhead according to  claim 19 , wherein said continuously curved fifth blade portion has a radius of curvature of between about 0.2″ and 0.5″.  
   
   
       24 . An arrowhead according to  claim 19 , further comprising means for limiting the deployment angle of said deployable blade assemblies.  
   
   
       25 . An arrowhead according to  claim 24 , wherein said means limits the maximum deployment angle of said deployable blade assemblies in the range of about 90 degrees and 170 degrees.