Abstract:
A spinnerbait fishing lure and frame therefor that is sufficiently rigid to minimize system losses and thereby create more blade-induced vibration. The frame has a first leg, a second leg extending from the first leg to cause the frame to have a V-shaped profile lying in a plane, and a vertex defined by the first and second legs, wherein the frame at least predominantly has a flat outer cross-sectional shape.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/521,801, filed Jul. 6, 2004. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention generally relates to spinnerbaits and related fishing lures, and more particularly a spinnerbait fishing lure frame constructed and formed in a manner that yield a fishing lure capable of performing more effectively than previous spinnerbait-type lures.  
         [0003]     Spinnerbaits are a type of fishing lure that attract fish by creating vibration and movement in the water. Spinnerbaits generally have a V or L-shaped frame formed of bent wire to define two legs. One or more blades or spinners are mounted with swivels and/or stirrup-shaped devises to one of the legs so as to be able to rotate as the lure is drawn through the water. The distal end of the second leg carries a hook, while an eyelet or other suitable feature for attaching a fishing line is formed at or near the vertex of the wire frame formed by the two legs. A weight is carried on the second leg adjacent the hook, as is typically a bait capable of attracting fish, such as a soft plastic worm or a skirt that hides the hook and ripples as the lure is drawn through the water. Due to the placement of the weight on the wire frame, the leg with the attached blades is above the leg with the hook and bait as the lure is drawn through the water.  
         [0004]     Movement of the blades of a spinnerbait is the primary attraction mechanism to a targeted fish. Blade motion is induced by the motion of the lure through the water both as the lure drops down to the desired retrieval depth and during retrieval. Vibrations in the water created by the motion of the blades are particularly attractive to predatory fish, since the vibrations are interpreted as the motion of a small wounded bait fish.  
         [0005]     In view of the above, it has been accepted that the frame of a spinnerbait must be flexible in order to maximize the vibrations that will attract fish as the lure moves through the water. In the past, the required flexibility has been typically achieved by producing the frame from flexible wire having a round cross-sectional shape. To promote flexibility, spinnerbait frames have also been formed from alloys, including shape-memory alloys such as nickel-titanium alloys (e.g., NITINOL®), chosen for their ability to provide extreme flexibility rather than rigidity.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     The present invention provides a spinnerbait fishing lure and frame therefor that is sufficiently rigid to create more blade-induced vibration.  
         [0007]     The frame comprises a first leg, a second leg extending from the first leg to cause the frame to have a V-shaped profile lying in a plane, and a vertex defined by the first and second legs, wherein the frame at least predominantly has a flat outer cross-sectional shape. According to a preferred aspect of the invention, the frame exhibits greater rigidity to deflection in the plane of the frame than to deflection out of the plane of the frame.  
         [0008]     In view of the above, it is believed that the frame greatly reduces system losses to promote more blade-induced vibration in the lure than possible with spinnerbaits having conventional flexible frames with round cross-sections. By minimizing system losses, the energy provided by movement of bait attached to the frame when traveling through the water is most efficiently transmitted to the blades and converted into blade motion and resultant vibrations for attracting fish. A pronounced resonant frequency can also be achieved with the frame because, in addition to minimal system losses, its reactance is high and vibrational bandwidth is relatively narrow.  
         [0009]     An additional benefit of the rigid frame of this invention is its extreme responsiveness when a jerk-retrieve is used because acceleration immediately translates into blade movement rather than bending of the frame due to inertia, as occurs with conventional flexible frames with round cross-sections. Inertia of a blade attached to the first leg of the frame is able to be more efficiently fed back to the bait attached to the second leg of the frame, inducing greater motion in the bait to create the illusion that the bait is a wounded bait fish.  
         [0010]     Other objects and advantages of this invention will be better appreciated from the following detailed description.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a side view of a spinnerbait fishing lure in accordance with an embodiment of this invention.  
         [0012]      FIG. 2  is a side view of a frame of the lure of  FIG. 1 .  
         [0013]      FIG. 3  is a cross-sectional view of the frame of  FIG. 2 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]     Illustrated in  FIG. 1  is a spinnerbait fishing lure  10  of a type that can be produced with a frame  12  in accordance with the present invention. As is generally conventional, the lure  10  includes a bait  14  and blades (spinners)  16 . The blades  16  are mounted with swivels or other suitable connectors to enable the blades  16  to rotate and vibrate as the lure  10  travels through water, thereby inducing vibrations in the water and motion in the bait  14 . While the bait  14  is shown configured to resemble a fish with a skirt to hide one or more hooks (not shown) attached to the bait  14 , the invention is not limited to any particular type or shape of bait  14 . Similarly, while the lure  10  is shown equipped with two blades  16 , the invention is not limited to any particular number, shape, size, etc., of blades  16 .  
         [0015]     The frame  12  of the lure is shown in greater detail in  FIGS. 2 and 3 . The frame  12  has a generally V-shaped or L-shaped profile in a plane defined by a pair of legs  18  and  20  that intersect to define a vertex  22  of the frame  12 . Suitable lengths for the legs  18  and  20  are about 2.75 and 1.78 inches (about 7 and about 4.5 centimeters), respectively, though it is foreseeable that the absolute and relative lengths of the legs  18  and  20  could differ. As depicted in  FIG. 2 , the legs  18  and  20  are generally oriented about ninety degrees to each other, though this also could be varied. The legs  18  and  20  and vertex  22  are formed to have through-holes  24 . By referring back to  FIG. 1 , it can be seen that some of the through-holes  24  in the first leg  18  define locations at which the blades  16  are attached to the upper leg  18 , and a through-hole  24  on the lower leg  20  provides a location for attaching the bait  14 . The through-hole  24  located at the vertex  22  provides a location at which a fishing line (not shown) can be attached to the frame  12 . A suitable diameter for the through-holes  24  in the legs  18  and  20  is about 0.06 inch (about 1.5 millimeters), and a suitable spacing for the through-holes  24  along the length of the first leg  18  is about 0.375 inch (about 1 centimeter) apart. The through-hole  24  at the vertex  22  is preferably larger, for example, about 0.08 inch (about 2 millimeters) in diameter. As shown, additional through-holes  26  may also be defined in the frame  12 .  
         [0016]     From  FIGS. 2 and 3 , it is evident that the frame  12  does not have a round cross-sectional shape, but instead predominantly has a flat outer cross-sectional shape. By predominantly, the intent is that a sufficient portion of the length of the frame  12  has the desired flat outer cross-sectional shape to produce a measurable increase in the rigidity of the frame  12 . In  FIG. 3 , it can be seen that the flat outer cross-sectional shape of the frame  12  is defined in part by two oppositely-disposed surfaces  28  oriented generally parallel to the plane of the frame  12 . An oppositely-disposed second pair of surfaces  32  and  34  intersect the first pair of surfaces  28  and  30 , resulting in the frame  12  having a quadrangular cross-sectional shape. Though its dimensions (including dimensional ratios) can vary and through-holes  24  and  26  are present, the frame  12  preferably has a flat outer cross-sectional shape, more preferably the quadrangular-shaped cross-section exterior shown in  FIG. 3 , throughout its extent. As will be discussed below, the first pair of surfaces  28  and  30  are generally flat and substantially parallel to the plane of the frame  12 . The second surfaces  32  and  34  may also be flat and generally perpendicular to the plane of the frame  12  (and therefore perpendicular to the first surfaces  28  and  30 ), though tolerances and irregularities during forming of the frame  12  will not necessarily result in the second surfaces  32  and  34  being as flat as the first surfaces  28  and  30 .  
         [0017]     As seen from  FIG. 3 , the cross-section of the frame  12  is such that the width of the frame  12  (in the plane of the frame  12 ) is significantly greater than the thickness of the frame  12  (in the direction transverse to the plane of the frame  12 ). The first pair of surfaces  28  and  32  are shown as consistently having an outermost width dimension (defining the width of the frame  12 ) that is greater than an outermost width dimension (defining the thickness of the frame  12 ) of the second pair of surfaces  32  and  32 . As a result, the frame  12  exhibits greater rigidity to deflection in the plane of the frame  12  than to deflection out of the plane of the frame  12 . From  FIG. 2 , it can be seen that the outermost width dimensions of the surfaces  28  and  30  are not constant but vary along the lengths of the legs  18  and  20 , due at least in part to accommodate the presence of the through-holes  24  and  26 . Though not limited to any particular dimensions, a suitable width for the leg  18  between through-holes  24  is about 0.09 inch (about 2.3 millimeters), a suitable width for the leg  20  between the cluster of through-holes  26  and the through-hole  24  is about 0.04 inch (about 1 millimeter), and a suitable width for the legs  18  and  20  across each through-hole  24  is about 0.12 inch (about 3 millimeters). In contrast, the outermost width dimensions of the second surfaces  32  and  34  can be substantially uniform along the entire lengths of the legs  18  and  20 , and generally will be constant if the frame  12  is formed from flat stock. As defined by the width dimensions of the second surfaces  32  and  34 , a suitable thickness for the frame  12  is about 0.032 inch (about 0.8 millimeter).  
         [0018]     As seen in  FIG. 2 , the leg  18  is substantially straight while the other leg  20  has a substantially straight portion immediately adjacent the first leg  18 , a distal portion defining the distal end of the second leg  20 , and a curved portion between and adjoining the straight and distal portions such that the distal portion is not parallel to the straight portion. The through-hole  24  located in the second leg  20  is formed at the distal end of the second leg  20 , and as a result of the curved portion is offset from the straight portion of the second leg  20 , such as by about 0.32 inch (about 8 millimeters).  
         [0019]     As noted above, a preferred aspect of the invention is that the frame  12  is relatively rigid, more so than conventional spinnerbait lure frames formed from round wire. While a variety of materials could be used to form the frame  12  of this invention, a preferred material is high tensile strength stainless steel. Titanium and its alloys can also be used, though in contrast to previous flexible frames formed for shape-memory nickel-titanium alloys, suitable titanium alloys for use with this invention do not contain intentional additions of nickel that would result in the flexible, shape-memory effect. Instead, suitable titanium alloys exhibit a very low modulus of elasticity after heat treatment. As also previously mentioned, the frame  12  can be formed from flat stock so that the frame  12  and each of its legs  18  and  20  can be readily produced to have the desired flat outer cross-sectional shape defined by the surfaces  28  and  30 . A suitable method for forming the frame  12  is by stamping, particularly if the starting material is flat stock. Alternative forming processes are also possible and within the scope of this invention. For example, the frame  12  could be machined (e.g., laser cut, EDM, etc.) from flat stock, which would yield a rectangular cross-sectional shape as a result of the surfaces  32  and  34  being flatter and perpendicular to the surfaces  28  and  30 . Other suitable processes include metal injection molding (MIM) and induction casting techniques.  
         [0020]     While not wishing to be held to any particular theories, the benefits of the rigid frame  12  of this invention are believed to be affirmed on the basis of the quality factor (Q) attainable with the frame  12 . As known, quality factor is a measure of loss (or efficiency) in electrical or mechanical systems relating to a system&#39;s resonant frequency, and is generally based on the relationship: 
 
Q=Reactance Resistance 
 
 which in turn is derived from 
 
Resonant Frequency F 
 
 where 
 
 F =(high cutoff frequency)−(low cutoff frequency)(upper &amp; lower cutoffs defined by −3 dB or 2 power roll-offs) 
 
         [0021]     Because of its cross-sectional shape, the frame  12  of this invention is considerably more rigid than frames formed of round wire. The rigidity of the frame  12  can be promoted by forming the frame  12  so that the in-plane surfaces  28  and  30  are wider than the transverse surfaces  32  and  40 , which greatly reduces flexure of the frame  12  in directions within the plane of the frame  12  and therefore in the rearward direction as the lure  10  is pulled through the water. It is believed that the rigidity of the frame  12  minimizes system losses (e.g., attributable to flexure), maximizes reactance, and provides a relatively narrow vibrational bandwidth, which in turn is believed to achieve a more pronounced resonant frequency. On this basis, the frame  12  of this invention can be characterized as a high-Q frame, especially when compared to previous spinnerbait frames formed from bent round wire of less rigid materials, and therefore readily and equally flexible in all directions transverse to the axis of the wire.  
         [0022]     While the invention has been described in terms of a preferred embodiment, it is apparent that other forms could be adopted by one skilled in the art. For example, the physical configuration of the lure  10  and frame  12  could differ from that shown, and materials, dimensions, and processes other than those noted could be use. Therefore, the scope of the invention is to be limited only by the following claims.