Abstract:
A bi-metal light weight self penetrating boat anchor includes flukes  18 A and  18 B and a crown  16  formed of light weight material, such as aluminum, and includes a shank  12  and stock  14  formed of heavier material such as stainless steel. The heavier shank assures that the shank will lie flat on the lake bottom when being dragged by the boat, and the stronger heavier stock resists bending or other deterioration when engaging obstacles at the lake bottom. The reduced weight of the crown and flukes permits the anchor to be of reasonable weight that is more conveniently handled by the boat operator.

Description:
FIELD OF THE INVENTION 
     This invention relates to a self penetrating boat anchor for engaging the bottom beneath a lake or other body of water and which penetrates the bottom in response to being dragged by the boat. More particularly, the invention involves a self penetrating boat anchor having flukes that pivot with respect to the shank to permit the flukes to dig into the lake bottom when the anchor is dragged, when either side of the anchor is in engagement with the lake bottom. 
     BACKGROUND OF THE INVENTION 
     Boat anchors are formed in various configurations for the purpose engaging the bottom beneath the body of water so that the anchor can hold itself to the bottom while it&#39;s anchor chain and line extend latterly and upwardly to the surface of the water and hold a boat or other floating object in a relatively stationary position. 
     One of the more popular styles of boat anchors is the Danforth anchor that is relatively lightweight for its size, and is useful for anchoring small boats. The anchor has a shank connected at one of its ends to an anchor chain, the other end of the shank is pivotally connected to a stock and a pair of flukes. The stock extends normal to the shank, and the flukes straddle the shank and are connected to the stock so that their pointed ends can pivot with respect to the shank and penetrate the lake bottom. When the anchor chain attempts to drag the anchor along the lake bottom, the flukes can pivot with respect to the stock, to extend at a downwardly sloped angle that causes them to penetrate the surface of the lake bottom, thereby holding to the bottom. This tends to terminate the lateral movement of the anchor, thereby restraining the movement of the boat or other floating objects at the surface of the water. 
     The anchors are made so that the pair of flukes that straddle the shank are rigidly connected to each other by a common stock. The stock extends laterally at the base of the shank and flukes, and the stock is pivotally connected to the shank. With this arrangement, the anchor can fall from the boat to the lake bottom, and then tilt in either direction until it&#39;s shank lies flat upon the lake bottom, and the flukes will have the opportunity to form an angle with respect to the shank, to extend downwardly into the lake bottom as the shank is being pulled across the lake bottom by the boat. 
     The prior art self penetrating boat anchors must be much heavier than the weight of water so as to the sink to the bottom of the lake and to resist upward lifting forces that might be caused by movement of the water. It is important that the shank of an anchor be of high specific gravity so that it will tend to lie flat upon the lake bottom even in response to being dragged by the boat to which it is tether. If the shank is of lightweight, low specific gravity construction it will be more likely to tilt upwardly as it is being dragged by the boat, so that it&#39;s flukes will have less opportunity to engage and penetrate the lake bottom. 
     Likewise, the shank must be of very strong material so that it can withstand the various forces applied to it by the boat dragging the anchor or forcing the anchor into the lake bottom, and to resist deterioration from various obstructions that might be encountered at the lake bottom. 
     Likewise, the stock of the boat anchor must be of very strong material so as to resist the forces applied to it under the same circumstances as the shank, and also being able to penetrate that lake bottom. The use of ferrous material for both the shank and the stock is desired for strength and weight purposes, so that the stock and shank can be of relatively small cross sectional area for the ability to penetrate the lake bottom. 
     In addition, the prior art has taught the use of ferrous materials, such as stainless steel, for use in all parts of a self-penetrating boat anchor, including the flukes, the crown, and the aforesaid elements. This provides the anchor with adequate weight and strength to perform its desired functions. 
     While the prior art anchors have been successful in function, there is a problem with the weight of an anchor particularly when the anchor is being handled at the level of the boat, by lifting the anchor out of the water for placement in the boat or lifting the anchor out of the boat for placement in the water. Obviously, the heavier and more massive the anchor, the better holding power it achieves with respect to the lake bottom, but the more difficult it is handle by the personnel in the boat, and the excessive weight of the anchor, together with it&#39;s shape, is hazardous to the boat with regard to marring scarring, or even rupturing the deck and/or bulk heads of the boat. 
     Applicant addresses the above noted problems by providing a bi-metal, lightweight self-penetrating boat anchor that utilizes different metals for different parts of the anchor. 
     SUMMARY OF THE INVENTION 
     Briefly described, the present invention provides a bi-metal, light weight self penetrating boat anchor for use with boats in which the anchor, it&#39;s chain and line are expected to be handled manually, and in which the light weight of the anchor is desirable when the anchor is being man handled. 
     The anchor includes the conventional shank that is pivotal with respect to the stock, flukes and crown of the anchor. The flukes, stock and crown are assembled so as to be rigidly attached to one another, whereas the shank is pivotal with respect to these elements, to extend at an acute angle to either side of the flukes. In the embodiment of the invention illustrated, the crown limits the pivotal movement of the flukes, with respect to the shank to an angle of 35° to either side of the shank. This angle can be increased or decreased as might be desired by reshaping the crown of the anchor, but must be limited to less than a right angle for proper penetration into the lake bottom. 
     The flukes of the anchor are substantially flat, with a strengthening rib of each fluke facing the shank. The flukes are necessarily broad so as to be able to engage the lake bottom with sufficient cross sectional area so as to perform their anchoring functions. Thus, the volume of material embodied in the flukes usually is greater than the volume of material embodied in the other elements of the anchor assembly. 
     Likewise, the crown that functions to raise the pivotal ends of the flukes away from the lake bottom so that the pointed distal ends can penetrate the lake bottom comprises a mass of material of sufficient volume. However, it is not necessary that either the flukes or the crown be fabricated of heavier metals because of the manner in which they function on the lake bottom. In contrast, however, the shank and the stock must be made of very strong and dense materials so that the weights and strengths of these parts are used in the function of an anchor. For example, the shank must be heavy in order to lie parallel to the surface of the lake bottom, thereby giving the flukes the opportunity to droop from their pivoted ends to their pointed distal ends toward engagement with the lake bottom. When the anchor is dragged by it&#39;s chain and line extending to the boat, the heavy shank tends to remain flat on the lake bottom until the boat is almost over the anchor and the anchor is lifted upwardly toward the boat. This gives the flukes and opportunity to penetrate the lake bottom. Likewise, the stock must be of strong material so as to withstand the forces normally applied to it when being dragged through the lake bottom or into engagement with obstructions with on the lake bottom. Moreover, both the shank and stock should be of relatively thin profile so that they also can penetrate the lake bottom in response to their movements imparted by the boat attempting to drag the anchor. 
     However, the flukes and crown of the invention that should be formed with more cross sectional surface area are fabricated of lighter weight material than the stock and shank, such as Aluminum, Magnesium or Titanium. This allows the anchor to be lighter in weight while retaining more mass in the stock and shank where it is important to retain the weight. 
     Thus, it is the object of this invention to provide an improved a self penetrating boat anchor of light weight that function adequately to anchor a boat or other floating objects, yet is of lighter than conventional weight for ease and handling and storing. 
     Another object of this invention is to provide a self penetrating boat anchor that includes parts thereof that are of dense, heavy metals that utilizes the weight of the metals for enhancing the functions of an anchor, and utilizes lighter weight metals in those parts of the anchor that do not require the parts to be of heavy weight for proper functioning of the anchor. 
    
    
     Other objects, features and advantages of the present invention will become apparent upon reading the following specification, when taken in conjunction with the accompany drawing. 
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is prospective illustration of a lightweight self-penetrating boat anchor. 
     FIG. 2 is a side view of the boat anchor of FIG. 1 in its configuration when the boat is dragging the boat anchor and its flukes are penetrating the lake bottom. 
     FIG. 3 is a rear view of the crown of the boat anchor, showing the stock extending through the crown and the pivotal end of the shank. 
     FIG. 4 is a side view of the crown of the boat anchor, showing a fluke and the shank partially in cross section. 
     FIG. 5 is an exploded prospected illustration of the crown of the boat anchor, showing portions of the stock, shank, and flukes. 
    
    
     DETAILED DESCRIPTION 
     Referring now in more detail to the drawings, in which like numerals indicate like parts throughout the several views, FIG. 1 illustrates the boat anchor  10  that includes a shank  12 , a stock  14 , a crown  16  and a pair of flukes  18 A and  18 B. The flukes straddle the shank  12 . 
     Shank  12  is a rectilinear, substantially flat strap that has a length or longitudinal axis  17  and that includes a pivotal, proximal end  20  (FIG. 5) and a distal end  21 . The distal end of the shank is formed with a slot  22  for connection to one end of an anchor  24  chain (FIG. 2) and a line (not shown) is connected to the other end of the anchor chain. The pivotal or proximal end  20  of the shank defines a stock opening  26  for engagement with the stock  14 , for surrounding the stock. 
     The shape of the shank  12  is important so that the shank can penetrate the lake bottom. The thickness “t” (FIG. 5) is less than one fifth the dimension of the width “w”, so that the flat or greater dimension w of the shank normally is maintained perpendicular to the lake bottom and does not present a broad engagement with lake bottom. Whereas the smaller dimension t is orientated so that it will engage the lake bottom (FIG. 2) and the shank will therefore have a better opportunity to penetrate the lake bottom as it is pulled by the anchor chain, line and boat in the direction indicated by arrow  28 . 
     To assist in the penetration of the stock into the lake bottom, the chain  24  is made of iron which is dense and therefore heavy, tending to avoid lifting of the distal end of the stock in response to upward sloped lifting of the line extending from the chain to the boat. 
     Stock  14  is rectilinear having a length or axis  31  and is circular in cross section and defines a slot  29  (FIG. 2) that is sized and shaped to receive the proximal ends  30  of the flukes  18 A and  18 B. The stock  14  extends through the stock opening  26  of the shank  12 , and protrudes on opposite sides of the shank, with it&#39;s length  31  extending normal to the length  17  of the shank  12 . 
     Crown  16  includes a support frame  34  (FIGS. 3-5) and limiting plates  36 A and  36 B. Crown support frame  34  is formed by extrusion and is cut to length and shape as necessary for its use. As can be seen from FIGS. 3 and 5, the extrusion includes opposed support platforms  37 A and  37 B, diverging base walls  38 A and  38 A′ and  38 B and  38 B′, parallel support walls  39 A and  39 B. The diverging base walls and parallel support walls define a central cavity  40  that receives the pivotal end  20  of shank  12 . The stock opening  26  of the shank  12  aligns with the aligned stock openings  42 A and  42 B of the crown support frame  34 , and the stock  14  is inserted through the aligned openings thereby pivotally connecting the stock  12  to the crown  16 . 
     Limiting plates  36 A and  36 B are mounted to the opposed support platforms  37 A and  37 B by connector screws  44 . The limiting plates are formed with a center cutout  46  (FIG. 5) and formed support tabs  48  and  49 . The support tabs  48  and  49  are shaped so as to mount to flat against the support platforms  37 A and  37 B of the crown support frame  34 . This allows the limiting plates to be sloped with respect to the surfaces of the opposed support platforms  37 A and  37 B. The distal edges  50  of the limiting plates  36 A and  36 B are formed with notches  51 A and  51 B. The notches register with the opposite edges of the shank  12  when the shank is tilted with respect to the flukes  18 . 
     The parallel support walls  39 A and  39 B of the crown support frame  34 , together with the overhanging portions  41 A,  41 A′, and  41 B,  41 B′ of the diverging base walls  38 A,  38 A′, and  38 B,  38 B′ form an oppositely facing “C” shaped slots  54 A and  54 B. The slots  54 A and  54 B are used to receive the strengthening flanges  19  of the flukes  18 , by sliding each strengthening flange into a “C” shape notch. When the flukes have been fully slide into the “C” shape notches, the proximal or base ends  21  of the flukes will be received in correspondingly sized and shapes slots  29  of the stock  14  (FIG.  2 ). Retaining clamps  58 A and  58 B surround stock  14  and fasten by means of bolts  59  to the flukes  18 A and  18 B. 
     As can be seen from FIG. 2, shank  12  pivots with respect to the flukes  18 A,  18 B, the crown  16  and the stock  14 . 
     The flukes  18 A and  18 B are of sufficient cross sectional area and require a substantial amount of material to form the desired cross sectional area. Flukes  18 A and  18 B are fabricated of lightweight metal, such as aluminum, magnesium, or titanium. 
     Likewise, the elements of crown  16  are formed of lightweight material, such as aluminum, magnesium, or titanium. 
     Shank  12  and stock  14  are made of more dense heavier material that is stronger and requires less volume of material to achieve the desired strength. Shank  12  and stock  14  are made of ferrous material, such as stainless steel which includes the strength and density desired. 
     The heavier weight of the shank  12  is utilized in the function of the anchor, by the weight causing the shank to lie flat against and penetrate the surface of the lake bottom, as illustrated in FIG.  2 . To enhance this flat position of the shank  12 , a chain  24  typically is used so that it&#39;s weight resists the upward lifting force that it is normally applied by the movement of a boat while dragging the anchor. 
     The stock  14  is also made of heavy metal, such as stainless steel, for similar purposes, so that it can resist bending or breaking when ensnared with obstructions on the lake bottom or when being dragged through the lake bottom. However, the lightweight material of the crown and flukes is not required for the above noted functions. The flukes, being of broad configuration, adequately engage the material of the lake bottom without having to be of heavy material. The sharp distal ends of the flukes are adequate in penetrating the lake bottom, and once the penetration is made, the lake bottom tends to draw the flukes deeper into the soil or other materials below the surface of the lake bottom. In the mean time, the crown  16  functions to hold the proximal, pivotal end of the flukes above the surface of the lake bottom so that the sharper distal ends of the flukes have the opportunity to form an angle with respect to the lake bottom for penetration purposes. Weight is not essential to the operation of the crown. However, the flukes must be heavier than water so they will not tend to float in water and the crown should be heavier than water so as to avoid the anchor losing some of its relative weight with respect to water at the crown. 
     The combination of the heavier material for the shank and stock of the anchor, together with the lighter weight material for the crown and flukes provides a combination that accomplishes the desired function of the anchor when on the lake bottom yet avoids excessive weight of the anchor when being handled at the surface of the water or in the boat. 
     Although preferred embodiments of the invention have been disclosed in detail herein, it will be obvious to those skilled in the art that variations and modifications of the disclosed embodiments can be made without departing from the spirit and scope of the invention as set forth in the following claims.