Method of manufacturing an archery broadhead with sintered components

Abstract
The present invention relates generally to an expanding-blade broadhead having a ferrule, a plurality of cutting blades pivotally coupled to the ferrule and a retaining collar releasably securing the cutting blades to the ferrule. The ferrule is formed with an integral boss which pivotally supports the cutting blade and with a threaded shank for attaching the broadhead to an arrow shaft in a conventional manner. Through the use of powdered metallurgy, the ferrule and retaining collar may be formed as monolithic components.
Description




BACKGROUND OF THE INVENTION




The present invention relates generally to an archery arrow and more specifically to the design and method of manufacture of the broadhead for an archery arrow.




The components of a typical archery broadhead include a ferrule or body having one or more blades extending therefrom. Additionally, the tip of the broadhead may be a separate component secured to the front of the ferrule. Two types of archery broadheads are generally known in the industry as fixed or replaceable blade broadheads and moveable or mechanical blade broadheads. The moveable blade broadheads, by design, are in a closed position in flight and open upon impact with the target.




Conventionally, the components of archery broadheads are manufactured using a variety of processes. The ferrule is conventionally turned or stamped with a male thread at the end where it attaches to an arrow shaft. Where the tip is not formed is an integral of the ferrule, an internal or female thread is formed on the front of the ferrule for receiving and securing the broadhead tip. Additional machining operations are necessary to provide the slots or other openings in the ferrule essential to the attachment of the blades. The blades are generally stamped steel with a uniform cross-section that requires subsequent grinding and honing operations to provide the sharpened edges. Thus, removable blades adds to the complexity of manufacturer, as does the use of irregular skin surface treatments on the ferrule. Tapered blades instead of stamped blades add strength and resistance to bending.




Broadhead components manufactured using conventional processes require a variety of costly equipment to achieve and maintain the precision essential to proper functioning of this commodity. Accordingly, there is a need to provide an efficient method of manufacturing from many of the broadhead components to reduce the cost, add design flexibility and still maintain the precision required.




SUMMARY OF THE INVENTION




It is an object of the present invention to provide a method of manufacturing broadhead components utilizing a process that reduces the number of operations, and thus simplifies the process, required to produce a finished product while maintaining the precision essential to the function of this commodity.




It is an additional object of the present invention to provide different materials as dictated by the particular application, in the manufacture of broadhead components utilizing the aforementioned process.




It is another object of the present invention to provide a monolithic ferrule, manufactured utilizing a powder injection molding (PIM) process incorporating integral design features necessary for the proper assembly and functioning of the broadhead.




It is a further object of the present invention to provide broadhead blades, manufactured by the PIM process, with tapered or otherwise varying cross sections so as to enhance the strength in aerodynamic qualities of the broadhead.




It is yet another object of the present invention to provide blades, manufactured by the PIM process, having scalloped, serrated or otherwise varying cutting edge treatments so as to enhance the cutting and penetration abilities of the broadhead.




It is an additional object of the present invention to provide a broadhead point, manufactured by the PIM process which may be used interchangeably with a variety of ferrules.




It is still another object of the present invention to provide a ferrule and broadhead point, either separately or integral with the ferrule, manufactured by the PIM process having a surface texture so as to enhance the aerodynamic and penetration qualities of the broadhead.




In accordance with a first preferred embodiment of the present invention, an expanding-blade broadhead is provided including a ferrule having an integral boss formed thereon, a plurality of cutting blades supported on the boss and pivotally coupled to the ferrule and a collar for retaining the blades on the boss while permitting free rotation thereof. A threaded shank portion is formed on the end of the ferrule opposite the point for securing the broadhead to the arrow shaft in a conventional manner. The use of powdered metallurgy and subsequent sintering processes provides a preferred, but not essential method of manufacturing the ferrule and retaining collar.




In accordance with a second preferred embodiment of the present invention, a fixed blade broadhead is provided including a ferrule having a blade receiving slot formed therein, a broadhead tip threadedly secured to the ferrule and a plurality of cutting blades disposed in the slots formed in the ferrule and releasably secured thereto by the broadhead tip. A threaded shank portion is formed on the end of the ferrule opposite the point for securing the broadhead to an arrow shaft in a conventional manner. The use of powdered metallurgy and subsequent sintering processes provides a preferred, but not essential method of manufacturing the ferrule, blades and broadhead tip.




These and other objects, features and advantages of the present invention will become apparent from the following description when viewed in accordance with the accompanying drawings and appended claims.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a perspective view of an expanding-blade broadhead in accordance with the present invention in which the blades are in a retracted position and with an arrow shaft illustrated in phantom lines;





FIG. 2

is a cross-section taken through lines II—II shown in

FIG. 1

;





FIG. 3

is a detailed perspective view illustrating the ferrule and retaining collar of the present invention;





FIG. 4

is a cross-sectional view of a portion of the ferrule and the retaining collar shown in

FIG. 3

;





FIG. 5

is an exploded side view illustrating the components of the expanding-blade broadhead of the present invention;





FIG. 6

is a partial cross-section illustrating the pivotal connections between the ferrule and the cutting blade;





FIG. 7

is a side view of the expanding-blade broadhead shown in a retracted position;





FIG. 8

is a side view of the expanding-blade broadhead shown in the deployed position;





FIG. 9

is an exploded side view of a fixed-blade broadhead in accordance with the present invention with an arrow shaft illustrated in phantom lines;





FIG. 10

is a cross-sectional view taken through the ferrule portion of the broadhead illustrated in

FIG. 9

;





FIG. 11

is an alternate embodiment of a ferrule for the fixed-blade broadhead having a surface texture treatment;





FIG. 12

is a cross-sectional view taken through the ferrule portion of the broadhead illustrated in

FIG. 11

;





FIG. 13

is a detailed cross-section view taken through the blade portion of the broadhead illustrated in

FIG. 9

showing tapered blade possibilities;





FIG. 14

is an alternate embodiment of the blade for the fixed blade broadhead assembly illustrated in

FIG. 9

;





FIG. 15

is a schematic diagram generally illustrating the method of manufacturing components of the broadhead in accordance with the present invention using powdered metallurgy technology; and





FIG. 16

is a flow chart illustrating the method of manufacturing the components of the broadhead in accordance with the present invention using powdered metallurgy technology.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS




With reference now to the

FIGS. 1-8

, a first preferred embodiment of the present invention is illustrated in the form of an expandable-blade broadhead. Broadhead


10


includes ferrule


12


, cutting blades


14


pivotally coupled to ferrule


12


and collar


16


disposed over an end of ferrule


12


for retaining cutting blades


14


thereon.




A substantially conical or trocar shaped tip


18


is formed at a forward end of ferrule


12


. The body


20


of ferrule


12


is generally conical or trocar shaped having a triangular cross-section as best seen in FIG.


2


. Each of the vertices


22


of body


20


has a slot


24


formed therein which receives cutting blade


14


when in the retracted position. Ferrule


12


further has a base portion


26


having three lugs


28


extending radially from the ferrule. A boss


30


extends from the radial face


32


of lug


28


. Shank


34


extends rearwardly from base portion


26


and has a male threaded portion formed at the end thereof for operably coupling broadhead


12


to arrow shaft


38


.




Cutting blades


14


have a cutting edge


40


formed thereon. Aperture


42


is formed in a bottom portion of cutting blade


14


and is adapted to received boss


30


for pivotally coupling cutting blade


14


to ferrule


12


. Collar


16


is slidably received over shank


34


and has an annular skirt portion


44


with fingers


46


extending longitudinally forward such that fingers


46


are positioned adjacent to lugs


28


formed on ferrule


12


. A radial face


48


defined by fingers


46


is generally parallel to but spaced apart from radial face


32


to further define slot


24


. As best seen in

FIG. 6

a slight clearance is provided between the end of boss


30


and the radial face


48


of finger


46


such that collar


16


may be readily positioned onto ferrule


12


, while at the same time sufficiently retaining cutting blade


14


onto boss


30


.




As best seen in

FIG. 5

, broadhead


10


is threadedly secured to arrow shaft


38


such that the forward face


50


of arrow shaft


38


pushes retaining collar


16


onto ferrule


12


. As presently preferred, a compliant element


52


is interdisposed between rearward face


54


formed on retaining collar


16


and forward face


50


of arrow shaft


38


to prevent loosening therebetween.




While various design features have been described above, one skilled in the art will readily recognize that certain modifications, variations and changes may be made without departing from the scope of the invention. In this regard the overall shape and geometric configuration of the ferrule may be adapted to various shapes. In addition, the expanding broadhead may incorporate more or less cutting blades as the particular application requires. The retaining collar may be secured to the ferrule by other suitable manners. The shaft of the ferrule may be formed of a separate piece from the body of the ferrule.




As previously indicated, some of the components of broadhead


10


, and in particular ferrule


12


and retaining collar


16


may be manufactured using a powdered metallurgical manufacturing process resulting in monolithic components. The powdered metallurgical process permits net shape or near net shape parts which have intricate design features. Furthermore, the powdered metallurgical process provides greater control over the shape and weight of the broadhead, and also improves the overall strength of the broadhead. The powdered metallurgical process also eliminates many fabricating and machining steps associated with conventional broadhead manufacturing.




With references now to

FIGS. 9-14

, a second preferred embodiment of the present invention is illustrated in the form of a fixed-blade broadhead. Broadhead


110


includes ferrule


112


, cutting blades


114


releasably secured to ferrule


112


. A conical or trocar shaped tip


118


is threadedly secured at a forward end of ferrule


112


and functions to releasably secure cutting blades


114


thereon. The body


120


of ferrule


112


is generally conically shaped having a triangular cross-section as best seen in FIG.


10


and has a shank


134


extending rearwardly therefrom. Each of the vertices


122


of body


120


has a T-shaped


124


formed therein which releasably secures cutting blades


114


to ferrule


112


.




Cutting blades


114


have a cutting edge


140


formed along the distal edge thereof. As best seen in

FIG. 13

, a bead


142


having a profile which compliments T-shaped slot


124


is formed along the proximal edge of cutting blade


114


. A generally triangular aperture


144


is formed in the body of cutting blade


114


to reduce the overall weight of the broadhead and distribute the mass of the blade around its perimeter. As presently preferred, cutting blade


114


has a tapering cross-section from the proximal edge


146


to the distal cutting edge


140


.




Slot


124


is configured to receive the proximal edge


146


of cutting blade


114


including bead


142


. Cutting blade


114


is slid axially into slots


124


formed in ferrule


112


. A threaded shank


148


is formed on the back surface of broad tip point


118


and is received in a threaded aperture


152


formed in ferrule


112


. In this way, broadhead tip


118


retains and secures cutting blades


114


with ferrule


112


. While a T-shaped slot configuration and complimentary bead profile is presently preferred, one skilled in the art will recognize that other slot configurations and bead profiles (such as L-shaped, circular, square, etc.) which cooperate to releasably secure blades


114


to ferrule


112


are contemplated by the present invention.




Broadhead


110


may be threadedly secured to arrow shaft


154


in the manner heretofore described. A compliant element (not shown) may be interdisposed between ferrule


112


and arrow shaft


154


to prevent loosening therebetween. As presently preferred, blades


114


are releasably secured to ferrule


112


by tip


118


. However, one skilled in the art will recognize that ferrule


112


could be configured such that a retaining element disposed over shank


134


or arrow shaft


154


functions to releasably secure blades


114


to ferrule


112


.




With reference now to

FIG. 11

, an alternate embodiment of the ferrule is illustrated. The body


120


′ of ferrule


112


′ is generally pyramidally shaped having a triangular cross-section as best seen in FIG.


12


. Each of the vertices


122


′ of body


120


′ has a slot


124


′ formed therein which receives cutting blades


114


. The planer surfaces


121


′ of body


120


′ have a generally textured surface formed thereon for enhancing aerodynamic and penetration properties of the broadhead. In this regard, U.S. Pat. No. 5,871,410, the disclosure of which is expressly incorporated by reference herein, discloses a broadhead in which the ferrule has such a textured surface.




With reference now to

FIG. 14

, an alternate embodiment of the cutting blades utilized in the present invention is illustrated. Specifically, cutting blade


114


′ is generally triangularly configured having a cutting edge


140


′ formed on a distal edge thereof. In addition, a plurality of scallops or serrations


141


′ are formed in the cutting edge to further facilitate cutting of the broadhead upon impact. Cutting blade


114


′ further includes a bead disposed along a proximal edge thereof for releasably securing blade


114


′ within ferrule


112


in a manner hereto for described.




With reference now to

FIGS. 15 and 16

, a general description of a preferred method of manufacturing a broadhead in accordance with the present invention will now be described. A more detailed description is set forth in U.S. application Ser. No. 09/546,146 filed on Apr. 10, 2000 and entitled “Broadhead and Method Of Manufacture”, the disclosure of which is expressly incorporated by reference herein. The method of manufacture is schematically illustrated in flow chart


100


.




The manufacturing process is initiated by blending metal powder and binder to form a powdered metal composition as represented at block


102


. When blending, the metal powder and binder are typically premixed in a first blending step


102




a


and then fully mixed to a near homogenous mixture and pelletized in a second blending step


102




b


. In this regard, a particular metal such as high carbon steel or titanium is mixed with a suitable binder such as a plastic or wax to form a powdered metal composition. Alternately, plastic, ceramic or composite materials suitable for powder injection molding (PIM) may be substituted for the powdered metal composition described above. Next, as represented in block


104


, the powdered metal composition is injected into a broadhead mold


105


having the particular design configurations for fabricating ferrule


12


and collar


16


illustrated in

FIGS. 1-8

, or alternately for fabricating ferrule


112


, cutting blade


114


and/or tip


118


. One skilled in the art will recognized that the various PIM components of broadhead


110


are formed separately. Through the use of pressure or other means, the powdered metal composition is compacted into a greenware broadhead component having the precise geometric configuration of the final product (although approximately 20% larger than the end design to account for shrinkage during subsequent processing) and moderate densification (on the order of approximately 50 densification).




Next, as represented in block


106


, the greenware broadhead component is processed to eliminate the binder from the metal without melting the constituent metal, thereby forming a powdered metal broadhead component. As presently preferred, the greenware broadhead component is immersed in a solvent to separate a portion of the binder from the powdered metal as illustrated in block


106




a


. The greenware broadhead component is removed from the solvent and placed in a thermal debinding furnace represented at block


106




b


where any remaining binder is burned off. The thermal debinding furnace may also be employed to perform a pre-sintering step. While the debinding steps is described as a combination of chemical and thermal processes, one skilled in the art will readily recognize that any process or combination of processes could be employed to debind the greenware broadhead. At this point, the powdered metal broadhead component is still in a moderate densification state.




As represented at block


108


, the powdered metal broadhead component is next placed in a sintering furnace and sintered at an elevated temperature and pressure to achieve near full density thereof. The sintering processing parameters are defined such that the broadhead reaches a density of at least 97%. During the sintering process, the overall size of the broadhead shrinks approximately 20%. Once sintering is complete, the broadhead component has a net shape and does not require further machining. In addition, the various features including slots, bosses and threaded shanks are already formed in the ferrule. Lastly, as represented at block


110


, cutting blades are secured to the ferrule in a final assembly process of the broadhead.




As presently preferred, the broadhead components of the present invention are fabricated using a powdered metal technology. However, one skilled in the art will readily recognize that other powdered materials such as ceramics or plastics may be suitable, and thus utilized herein. The determination of the exact materials are dictated by the requirements of a given application.




From the foregoing description, one skilled in the art will readily recognize that the present invention is directed to an archery broadhead design and a method of manufacturing same. While the present invention has been described with particular reference to preferred embodiments, one skilled in the art will recognize from the foregoing discussion and accompanying drawings and claims, that changes, modifications and variations can be made in the present invention without departing from the spirit and scope thereof as defined in the following claims.



Claims
  • 1. A method of manufacturing an archery broadhead comprising:powder injection molding at least one broadhead component selected from the group consisting of a ferrule and a blade; sintering said at least one broadhead component at an elevated temperature to form a sintered broadhead component; and connecting said blade to said ferrule.
  • 2. The method of manufacturing an archery broadhead of claim 1 wherein said blade is releasably secured to said ferrule with a retainer.
  • 3. The method of manufacturing an archery broadhead of claim 1 wherein said blade is pivotally coupled to said ferrule with a retainer.
  • 4. The method of manufacturing an archery broadhead of claim 1 further comprising:forming a greenware ferrule from a powdered composition; sintering said greenware ferrule at an elevated temperature to form a sintered ferrule; and connecting said blade to said sintered ferrule with said retainer.
  • 5. The method of manufacturing an archery broadhead of claim 4 wherein forming a greenware ferrule comprises forming said ferrule having a shank portion extending from an end thereof.
  • 6. The method of manufacturing an archery broadhead of claim 4 wherein forming a greenware ferrule comprises forming said ferrule having a tip portion extending from an end thereof.
  • 7. The method of manufacturing an archery broadhead of claim 4 wherein forming a greenware ferrule comprises forming a ferrule having a boss formed thereon, said boss being received in an aperture formed in said blade to pivotally couple said blade to said ferrule.
  • 8. The method of manufacturing an archery broadhead of claim 4 wherein forming a greenware ferrule comprises forming a ferrule having a slot formed therein and said blade is received within said slot to releasably secure said blade to said ferrule.
  • 9. The method of manufacturing an archery broadhead of claim 1 further comprising:forming a greenware blade from a powdered composition; sintering said greenware blade at an elevated temperature to form a sintered blade; and connecting said sintered blade to said ferrule with said retainer.
  • 10. The method of manufacturing an archery broadhead of claim 9 wherein said ferrule is provided with a longitudinal slot and said blade is received within said slot to releasably secure said blade to said ferrule.
  • 11. The method of manufacturing an archery broadhead of claim 10 wherein forming a greenware blade comprises forming said greenware blade having a bead along an edge thereof, said bead received within said slot when said sintered blade is releasably secured to said ferrule.
  • 12. The method of manufacturing an archery broadhead of claim 8 further comprising:forming a plurality of greenware blade from said powdered composition; sintering said plurality of greenware blades at an elevated temperature to form a plurality of sintered blades; and connecting said plurality of sintered blades to said ferrule with said retainer.
CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of prior application Ser. No. 09/910,385 entitled “Broadhead and Method of Manufacture” filed on Jul. 20, 2001 now U.S. Pat. No. 6,595,881, which is a continuation in part of prior application Ser. No. 09/546,146 entitled “Broadhead and Method of Manufacture” filed on Apr. 10, 2000 now U.S. Pat. No. 6,290,903 and which also claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 60/219,474 filed on Jul. 20, 2000 and entitled Expanding Archery Broadhead, the specification and drawings of which are hereby expressly incorporated by reference.

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Entry
“An Introduction to Injection Molding Metals & Ceramics”, Jun. 1999, pp. 4-5.
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Web site for Cabela's—http://www.cabelas.com, “BoneBuster® Broadheads”.
Provisional Applications (1)
Number Date Country
60/219474 Jul 2000 US
Continuation in Parts (1)
Number Date Country
Parent 09/546146 Apr 2000 US
Child 09/910385 US