USRE40273E1 - Method of manufacturing an archery broadhead with sintered components - Google Patents

Abstract

The present invention relates generally to a method of manufacturing broadhead components utilizing a powder injection molding (PIM) process that reduces the number of operations, thus simplifying the manufacturing process required to produce a finished product while maintaining the precision essential to the function of this commodity. The method of manufacturing includes powder injection molding one or more than one components for a broadhead, sintering the component(s) at an elevated temperature to form component(s) and assembling the component(s) to form a broadhead.

Description

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.

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 as 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 add to the complexity of manufacturer manufacturing, 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 of 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 and 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 inFIG. 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 inFIG. 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 inFIG. 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 inFIG. 11;

FIG. 13 is a detailed cross-section view taken through the blade portion of the broadhead illustrated inFIG. 9 showing tapered blade possibilities;

FIG. 14 is an alternate embodiment of the blade for the fixed blade broadhead assembly illustrated inFIG. 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 theFIGS. 1-8, a first preferred embodiment of the present invention is illustrated in the form of an expandable-blade broadhead. Broadhead10 includesferrule12,cutting blades14 pivotally coupled toferrule12 andcollar16 disposed over an end offerrule12 for retainingcutting blades14 thereon.

A substantially conical or trocar shapedtip18 is formed at a forward end offerrule12. Thebody20 offerrule12 is generally conical or trocar shaped having a triangular cross-section as best seen in FIG.2. Each of thevertices22 ofbody20 has aslot24 formed therein which receivescutting blade14 when in the retracted position.Ferrule12 further has abase portion26 having threelugs28 extending radially from the ferrule. Aboss30 extends from theradial face32 oflug28. Shank34 extends rearwardly frombase portion26 and has a male threadedportion36 formed at the end thereof for operably couplingbroadhead12 toarrow shaft38.

Cutting blades14 have acutting edge40 formed thereon.Aperture42 is formed in a bottom portion ofcutting blade14 and is adapted to received receiveboss30 for pivotallycoupling cutting blade14 toferrule12.Collar16 is slidably received overshank34 and has anannular skirt portion44 withfingers46 extending longitudinally forward such thatfingers46 are positioned adjacent tolugs28 formed onferrule12. A radial face48 defined byfingers46 is generally parallel to but spaced apart fromradial face32 to further defineslot24. As best seen inFIG. 6 a slight clearance is provided between the end ofboss30 and the radial face48 offinger46 such thatcollar16 may be readily positioned ontoferrule12, while at the same time sufficiently retainingcutting blade14 ontoboss30.

As best seen inFIG. 5,broadhead10 is threadedly secured toarrow shaft38 such that theforward face50 ofarrow shaft38pushes retaining collar16 ontoferrule12. As presently preferred, acompliant element52 is interdisposed betweenrearward face54 formed on retainingcollar16 and forward face50 ofarrow shaft38 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 ofbroadhead10, and inparticular ferrule12 and retainingcollar16 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 toFIGS. 9-14, a second preferred embodiment of the present invention is illustrated in the form of a fixed-blade broadhead.Broadhead110 includesferrule112, and cuttingblades114 releasably secured toferrule112. A conical or trocar shapedtip118 is threadedly secured at a forward end offerrule112 and functions to releasablysecure cutting blades114 thereon. Thebody120 offerrule112 is generally conically shaped having a triangular cross-section as best seen in FIG.10 and has a shank134 extending rearwardly therefrom. Each of thevertices122 ofbody120 has a T-shapedslot124 formed therein which releasably secures cuttingblades114 toferrule112.

Cuttingblades114 have acutting edge140 formed along the distal edge thereof. As best seen inFIG. 13, abead142 having a profile which compliments T-shapedslot124 is formed along the proximal edge of cuttingblade114. A generallytriangular aperture144 is formed in the body of cuttingblade114 to reduce the overall weight of the broadhead and distribute the mass of the blade around its perimeter. As presently preferred, cuttingblade114 has a tapering cross-section from theproximal edge146 to thedistal cutting edge140.

Slot124 is configured to receive theproximal edge146 of cuttingblade114 includingbead142. Cuttingblade114 is slid axially intoslots124 formed inferrule112. A threadedshank148 is formed on the back surface ofbroad tip point118 and is received in a threadedaperture152 formed inferrule112. In this way,broadhead tip118 retains and secures cuttingblades114 withferrule112. 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 releasablysecure blades114 to ferrule112 are contemplated by the present invention.

Broadhead110 may be threadedly secured toarrow shaft154 in the manner heretofore described. A compliant element (not shown) may be interdisposed betweenferrule112 andarrow shaft154 to prevent loosening therebetween. As presently preferred,blades114 are releasably secured toferrule112 bytip118. However, one skilled in the art will recognize thatferrule112 could be configured such that a retaining element disposed over shank134 orarrow shaft154 functions to releasablysecure blades114 toferrule112.

With reference now toFIG. 11, an alternate embodiment of the ferrule is illustrated. Thebody120′ offerrule112′ is generally pyramidally shaped having a triangular cross-section as best seen in FIG.12. Each of thevertices122′ ofbody120′ has aslot124′ formed therein which receives cuttingblades114. Theplanar surfaces121′ ofbody120′ 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 toFIG. 14, an alternate embodiment of the cutting blades utilized in the present invention is illustrated. Specifically, cuttingblade114′ is generally triangularly configured having acutting edge140′ formed on a distal edge thereof. In addition, a plurality of scallops orserrations141′ are formed in the cutting edge to further facilitate cutting of the broadhead upon impact. Cuttingblade114′ further includes a bead disposed along a proximal edge thereof for releasably securingblade114′ withinferrule112 in a manner hereto for described.

With reference now toFIGS. 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 inflow chart100.

The manufacturing process is initiated by blending metal powder and binder to form a powdered metal composition as represented atblock102. When blending, the metal powder and binder are typically premixed in afirst blending step102a and then fully mixed to a near homogenous mixture and pelletized in asecond blending step102b. 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. Alternatively, plastic, ceramic or composite materials suitable for powder injection molding (PIM) may be substituted for the powdered metal composition described above. Next, as represented inblock104, the powdered metal composition is injected into abroadhead mold105 having the particular design configurations for fabricatingferrule12 andcollar16 illustrated inFIGS. 1-8, or alternately for fabricatingferrule112, cuttingblade114 and/ortip118. One skilled in the art will recognized that the various PIM components ofbroadhead110 are formed separately. Through the use of pressure or other means, the powdered metal composition is compacted into a greenware broadband 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 inblock106, 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 inblock106a. The greenware broadhead component is removed from the solvent and placed in a thermal debinding furnace represented atblock106b 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 atblock108, 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 atblock110, 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 (12)

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 , with a powdered metal composition, a ferrule including a body and defining a slot;

sintering said at least one broadhead component ferrule at an elevated temperature to form a sintered broadhead component ferrule, the slot being formed and bounded substantially by metal; and

connecting said a blade to said ferrule.

2. The method of manufacturing an archery broadhead ofclaim 1 wherein said blade is releasably secured to said ferrule with a retainer.

3. The A method of manufacturing an archery broadhead ofclaim 1 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,

wherein said blade is pivotally coupled to said ferrule with a retainer so that the blade is expandable from a retracted position to a deployed position.

4. The method of manufacturing an archery broadhead ofclaim 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 a retainer.

5. The method of manufacturing an archery broadhead ofclaim 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 ofclaim 4 wherein forming a greenware ferrule comprises forming said ferrule having a tip portion extending from an end thereof.

7. The A method of manufacturing an archery broadhead ofclaim 4 comprising:

powder injection molding at least one broadhead component selected from the group consisting of a ferrule and a blade;

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,

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 ofclaim 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 ofclaim 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 a retainer.

10. The method of manufacturing an archery broadhead ofclaim 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 A method of manufacturing an archery broadhead ofclaim 10 comprising:

powder injection molding at least one broadhead component selected from the group consisting of a ferrule and a blade;

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,

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,

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 ofclaim 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 a retainer.

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