FIELD OF THE INVENTION 
     The present invention is in the area of hand-held striking tools, such as hammers, and pertains more specifically to the interface between head and handle of a striking tool. 
     BACKGROUND OF THE INVENTION 
     Hand-held striking tools have been used for centuries by people in a variety of disciplines as leveraged devices to provide a striking force to accomplish a seemingly endless variety of tasks. For example, a claw hammer allows a user doing carpentry work to deliver sufficient striking force to drive a nail into wood. A claw hammer is also used for removing a nail or ripping apart lumber using its claw. A sledge hammer is another common hand-held striking tool used to deliver sufficient striking force for heavy work such as driving a stake, chisel, or driving a wedge into masonry, stone, wood, or other hard materials. Another common hand-held striking tool is a ball peen hammer used to deliver sufficient striking force for shaping and fitting metal, and for driving machine chisels, rivet sets, machine wedges, and other similar tools. 
     As previously described, hand-held striking tools are commonly used as third class levers to provide a striking force to accomplish tasks such as driving a nail into a piece of wood, bending or forming metal, breaking a rock, and other similar tasks. Third class levers are levers where a fulcrum, also referred to as a pivot point, is at one end of a bar or rod. A load to be overcome is an object creating resistance at the opposite end of a bar or rod. The effort, or force, to be applied to a third class lever is somewhere in between the fulcrum and load. In the case of a hand-held striking tool such as a claw hammer, the fulcrum is a wrist with the force being provided by the deceleration of the movement of a hammer handle (bar or rod) at the wrist. The load in this case is a resistance presented by a piece of wood into which the nail is being driven. 
     The head of the hand-held striking device is commonly a significant distance from the fulcrum and moves faster than the movement being applied at a user&#39;s hand, which is near the fulcrum. The increased speed of the head multiplies the applied force with which a striking device head strikes a nail or digs into the dirt. The longer a claw hammer&#39;s handle, for example, the faster the head and the greater the force that strikes a nail and overcomes the resistance of the wood. This principle applies to all other hand held striking devices, and is intensified in long-handled striking devices such as a pickaxe, or an axe. 
     Hand-held striking tools are also commonly used as first-class levers to provide a lifting or prying force to accomplish a variety of tasks. For example, some hand-held striking devices are used to pull nails out of a piece of wood, tear apart pieces of wood or other building material, pry loose a large rock, lift a log, and the like. First-class levers are levers wherein the load to be overcome is at or near one end of a rod or bar, the effort, or force is applied at or near the other end of the same rod or bar, and the fulcrum, or pivot, is somewhere along the rod or bar in between the applied force and load. 
     An example of a hand-held striking tool being used as a first-class lever is a claw hammer being used to pull out nails, wherein the load to be overcome is the wood causing friction against an embedded nail. Another example of a hand-held striking tool being used as a first-class lever is a pickaxe being used to pry out a rock or tree root embedded in dirt or rock, where the load to be overcome is the dirt or rock causing friction against an embedded rock or tree root. Whenever a hand-held striking tool is used as a first-class lever, the force is applied at one end of a long handle. The fulcrum is typically near the other end of the handle that holds the head. 
     The load for a hand-held striking tool being used as a first-class lever, such as in a claw hammer or a pickaxe, is typically very close to the fulcrum. Whereas the force for a hand-held striking tool being used as a third-class lever is typically relatively far away from the fulcrum. During prying or pulling tasks, the load applied is therefore moved less distance than the hand, which is at the opposite end of the lever, and applying the force. This multiplies the force in which the claw hammer head pulls against a nail, or a pickaxe pulls against a rock. 
     The weakest part of a hand-held striking device is the interface between the handle and the head. The conventional methods of interfacing a striking device head and handle, which are typically made of distinct materials, such as metal and wood, allows striking and pulling stresses to promote head-to-handle loosening, damage, and separation. For example, the impact force at the head of a claw hammer, being used as a third-class lever against a nail, is often as high as 300 pounds. Because of the greater length of its handle and greater weight of its head, the striking force of the head of a pickaxes against the earth is many times greater. 
     The bending moment applied at the head-to-handle interface of a claw hammer been used as a first-class lever to pull a nail is often as high as 1000 foot-pounds. The bending moment levied against the head-to-handle interface of a pickaxe pulling heavy rocks away from the earth is typically several times more. 
     The effect of these forces is exacerbated when a user occasionally misses the target for which the strike is intended and strikes a hard object, such as the edge of a piece of wood or a rock, at the head-to-handle interface just below the head, causing further damage and weakening a head-to-handle interface. 
     Because of the inherent weakness in conventional head-to-handle interfaces, it is this point that most failures in hand-held striking devices occur. Methods have been devised to make head-to-handle interface configurations capable of withstanding impacts and pulling stresses described above without damage. These methods include using a handle made with a material, such as high-impact plastic or heavy-gauge rolled steel that has particularly high strength and resiliency to withstand extremely high impacts and pulling stress. These types of handles are typically encapsulated in a resilient material, such as natural or synthetic rubber, leather, or plastic, to provide some protection from the shock from impact and to give a user a good grip on the handle. Many users of hand-held striking devices, however, still prefer the look and feel of wooden handles. 
     As stated above, a problem with many conventional methods for increasing handle strength on hand-held striking devices is the inherent weakness in the design of interfaces. Current interfaces for hand-held striking tools typically comprise a handle whose end is shaped to make a tight fit through a shaped opening, or eye, in the head. Such a shaped opening is often tapered to be larger at the end of the opening opposite the side where the handle enters the head. Typically metal or wooden wedges are driven into the end of the handle to expand the handle into the eye of the head to attain a tight fit. A tight fit, however, does little to increase the strength of the conventional head-handle interface. 
     Another common method for securing conventional head-to-handle interfaces is by placing a bonding material, such as an epoxy adhesive, between the inner surface of the opening in the head and outer surface of the interface and of the handle. 
     The types of head-to-handle interfaces and methods of securing described above are commonly used on all types of hand-held striking tools, such as axes, sledge hammers, pickaxes, and the like. A problem with these conventional solutions is that the striking and pulling forces are concentrated over a short distance at the interface. The intensified stress at this small area is the cause of most hand-held striking tool failures. Head-to-handle interfaces made according to conventional art, regardless of the material of the handle or method of securing it to the head opening, often fail because of this concentrated stress. 
     What is clearly needed is an improved method and apparatus for securing the head of a striking tool to its handle, providing both a durable, long-lived head-to-handle interface and an integrated system of overstrike protection to the handle. Such a method and apparatus, in a preferred embodiment, overcomes an inherent weakness in conventional head-to-handle interface methods while preventing damage to the handle caused when a user misses a target and inadvertently strikes the handle against a hard object, damage that causes, further weakness in conventional head-to-handle interface methods. 
     SUMMARY OF THE INVENTION 
     In a preferred embodiment of the present invention, for a striking tool having a plane of substantial symmetry and a head with an eye for engaging a portion of a handle, a method for securing the handle to the head is provided, comprising the steps of (a) slotting the portion of the handle that extends into the eye of the head in the plane of substantial symmetry, providing a slot with a first width; (b) engaging a metal strongback unit in the slot, the strongback unit having a web with a thickness substantially the width of the slot; (c) engaging the handle and strongback assembly into the eye, and (d) spreading the web of the strongback unit until metal of the strongback unit urges against an inside surface of the head in the eye. 
     In a preferred embodiment the web has at least one opening at an upper edge for a spreading wedge, and the web is spread in assembly by driving a wedge into the handle and the opening in the web. The strongback unit may also comprise side elements having a second width greater than the web width, such that the side elements lie along opposite sides of the handle with the strongback unit engaged in the handle slot. Spreading the web urges the side elements against the inside surface of the head in the eye. Also in a preferred embodiment the side elements are shaped to fit a curvature of the inside surface of the head in the eye. In some cases the handle is formed on opposite sides of the slotted portion to accommodate the side elements of the strongback unit. 
     In another preferred embodiment the slot extends further along a length of the handle than the portion of the handle that extends into the eye of the head, and the strongback unit fills the slot, such that the side elements, with the handle and strongback engaged, provide an overstrike surface along a portion of the handle length below the head. In this embodiment as well, the handle may be formed along opposite sides along the slot edges to accommodate the side elements. 
     In still another preferred embodiment the strongback unit has a first web in an upper portion having a length equal to the handle portion extending into the eye, and a second web in a lower portion, the second web formed at a right angle to the first web, and wherein the handle is slotted with first and second slots at right angles to accommodate both webs. In this embodiment the second web comprises threaded holes, and an overstrike plate is assembled to the handle below the head on the side of the handle toward a striking surface of the head, the overstrike plate secured to the handle by fasteners extending through holes in the plate and the handle, and engaging the threaded holes in the lower web. 
     In another aspect of the invention a striking tool having a plane of substantial symmetry is provided, comprising a head with an eye for engaging a portion of a handle; a handle with a slot of a first width in the plane of substantial symmetry along a length of the portion of the handle extending into the eye; and a metal strongback unit in the slot, the strongback unit having a web with a thickness substantially the width of the slot. The striking tool is characterized in that the strongback unit is spread in the eye, urging metal of the strongback unit against inside surface of the head in the eye, to secure the head on the handle. In preferred embodiments the web has at least one opening at an upper edge for a spreading wedge, and the web is spread in assembly by driving a wedge into the handle and the opening in the web. 
     In some embodiments the strongback unit comprises side elements having a second width greater than the web width, such that the side elements lie along opposite sides of the handle with the strongback unit engaged in the handle slot. Spreading the web urges the side elements against the,inside surface of the head in the eye. The side elements may be shaped to fit a curvature of the inside surface of the head in the eye. Also, the handle may be formed on opposite sides of the slotted portion to accommodate the side elements of the strongback unit. 
     In another embodiment the slot extends further along a length of the handle than the portion of the handle that extends into the eye of the head, and the strongback unit fills the slot, such that the side elements, with the handle and strongback engaged, provide an overstrike surface along a portion of the handle length below the head. The handle may be formed along opposite sides along the slot edges to accommodate the side elements. 
     In yet another preferred embodiment the strongback unit has a first web in an upper portion having a length equal to the handle portion extending into the eye, and a second web in a lower portion, the second web formed at a right angle to the first web, and wherein the handle is slotted with first and second slots at right angles to accommodate both webs. The second web may comprise threaded holes, and an overstrike plate may be assembled to the handle below the head on the side of the handle toward a striking surface of the head, the overstrike plate secured to the handle by fasteners extending through holes in the plate and the handle, and engaging the threaded holes in the lower web. 
     In various embodiments of the present invention described in enabling detail below, an improved apparatus and method is provided for securing handles to heads of striking tools. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 a  is a side view of a metal strongback according to embodiment of the present convention. 
     FIG. 1 b  is a top view of the strongback of FIG. 1 a.    
     FIG. 2 a  is a broken view of a conventional hammer head to be used with the strongback of FIG. 1 a.    
     FIG. 3 a  is a side view of the end of a hammer handle used according to an embodiment of the present invention. 
     FIG. 3 b  is a view of the handle section of FIG. 3 a , rotated 90 degrees. 
     FIG. 3 c  is a top view of the handle section of FIG. 3 a.    
     FIG. 4 a  is a side view of the metal strongback of FIG. 1 a , the hammer head of FIG. 2 a  and the hammer handle of FIG. 3 a  assembled according to an embodiment of present invention, but not secured. 
     FIG. 4 b  is a side view of the assembled components of FIG. 4 a  secured together according to embodiment of the present invention. 
     FIG. 4 c  is a top view of the assembled components of FIG. 4 b.    
     FIG. 5 a  is a three-dimensional view of a strong back according to an alternative embodiment of the present invention. 
     FIG. 5 b  is a top view of a hammer handle fashioned to be used with the strongback of FIG. 5 a.    
     FIG. 5 c  is a side view of the strongback of FIG. 5 a , the hammer handle of FIG. 5 b  and the hammer head of FIG. 2 assembled according to an alternative embodiment of the present invention. 
     FIG. 6 is a simplified view of a metal strongback according to another alternative embodiment of the present invention assembled with a conventional hammer head. 
     FIG. 7 a  is side view of a hammer handle and fastening elements according to an alternative embodiment of the present invention. 
     FIG. 7 b  is a view at 90 degrees to the view of FIG. 7 a.    
     FIG. 7 c  is an assembly view showing a hammer head assembled to a hammer using the elements of FIGS. 1 a  and  7   b.    
     FIG. 8 a  is a side view showing an apparatus in an alternative embodiment of the present invention. 
     FIG. 8 b  is a side view of the apparatus of FIG. 8 a  showing the assembly completed. 
     FIG. 9 a  is an elevation view of yet another strongback according to an embodiment of the present invention. 
     FIG. 9 b  is a top view of a hammer head with the strongback of FIG. 9 a  used to enhance joining a handle to the head. 
     FIG. 9 c  is a side elevation view illustrating the head and handle from FIG. 9 b  in assembly. 
     FIG. 10 a  is a side view of still another strongback according to a preferred embodiment of the present invention. 
     FIG. 10 b  is a top view showing the strongback of FIG. 10 a  assembled with a handle into the eye of a hammer head. 
     FIG. 10 c  is head, handle, and fastening components in a side view for the embodiment described relative to FIG. 10 b.    
     FIG. 11 a  is a side view of a special wedge used in an embodiment of the present invention. 
     FIG. 11 b  is a top view of a handle, head and interface components, illustrating use of the wedge of FIG. 11 a.    
     FIG. 11 c  is an assembly view illustrating assembly of the components from FIGS. 11 a  and  11   b.   
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 a  is a side view of a metal strongback according to a preferred embodiment of the present convention. Strongback  101  comprises metal having relatively malleable or bendable properties, with a side  103  and side  104  positioned on opposite edges of a web  102 , providing a shape similar to a miniature I-beam. Sides  103  and  104  in this embodiment have outer surfaces about half-spherical in shape with inner surfaces being flat. In alternative embodiments however, the shape of outer and inner surfaces can vary greatly. Web  102  is provided having a height D 2  being approximately twice or more that of the depth of the eye of a conventional hammer head, and a width D 3  approximately equal to that of a conventional hammer handle Hole  106 , passing completely through Strongback  101  is provided as a means to accommodate a standard fastening device such as a threaded bolt set. Slotted openings  105  are provided in this embodiment as V-shaped notches cut, milled or fashioned by some other means to a depth D 1  into the top edge of Strongback  101 . 
     FIG. 1 b  is a top view of Strongback  101  of FIG. 1 a . The half-cylindrical shape of Sides  103  and  104 can be seen in this view, Sides  103  and  104  each having a width of D 5 . The thickness of Web  102  can also be seen in this view. 
     FIG. 2 a  is a broken view of a conventional hammer head to be used according to an embodiment of the present invention. Hammer head  201  has an eye  203  having a width D 3  at the bottom, essentially the same dimension as D 3  in FIG. 1 a , and a width D 4  at the top, width D 4  being somewhat larger than width D 3 . The varying dimensions create an opening somewhat larger in cross-sectional area at the top of Eye  203  than at the bottom, so that, in the process of attachment, when the top end of an inserted hammer handle is spread to dimension D 4 , the hammer head is held firmly in place. 
     FIG. 3 a  is a side view of the end of a hammer handle fashioned to join to a head using a strongback according to a preferred embodiment of the present invention. Handle  301  is provided having shoulders  302  milled, cut or fashioned by some other means into each of two Sides  303  to a depth of D 5  equal to that of Sides  103  and  104  of Strongback  101  of FIG. 1 b . The upper portion of Handle  301  above Shoulders  302  is shaved or milled to a width of D 3  and a height of D 2 , a height equal to that of the overall height of Strong back  101  of FIG. 1 a.    
     FIG. 3 b  is a side view of the handle section of FIG. 3 a . Slot  304  is shown in this view as cut, milled or fashioned by some other means into the center of Handle  301  to a depth of D 2  and having a width substantially equal to that of Web  102  of Strongback  101 FIG. 1 a.    
     FIG. 3 c  is a top view of the handle section of FIG. 3 a  showing the cutouts of shoulders  302  being of width D 5 , and slot  304  extending completely through the upper portion of Handle  301 . It will be apparent in this view that the overall shape of Strongback  101 , as seen in the top view of FIG. 1 b , matches exactly the shape created by the fashioning of shoulders  302  and slot  304  into Handle  301 , thus allowing for a close fit when Strongback  101  is inserted down into the top of Handle  301 . 
     FIG. 4 a  is a side view of the metal strongback of FIG. 1 a , the hammer head of FIG. 2 a  and the hammer handle of FIG. 3 a  assembled according to an embodiment of present invention. The purpose of this view is to show how the components described above are assembled together previous to the final securing of the assembled Handle  301  and Strongback  101  to hammer head  201  according to this embodiment of the present invention. In this view Strongback  101  shown in FIG. 1 a  is shown inserted down into the slotted top portion of Handle  301 , the bottom edge of Strongback  101  seated upon shoulders  302  and the bottom edge of slot  304 , and attached using a fastener  402 . Fastener  402  in this embodiment is a standard threaded bolt with a hexagonal cap secured by a standard threaded nut at the Opposite end. In alternative embodiments however, the type of fastener used in attaching Strongback  101  to Handle  301  can vary. The assembled Strongback  101  and Handle  301  are then inserted up through the eye of hammer head  201  until the top edge of Strongback  101  is flush with the top edge of hammer head  201 . 
     FIG. 4 b  is a side view of the assembled components of FIG. 4 a  secured together according to embodiment of the present invention. In this view the assembly of the components of FIG. 4 a  can be seen with the addition of wedges  401  which have been driven down into the open end of the handle and into slotted openings  105 . The outward force created by this action causes both the outer sides of the metal Strongback  101 , as well as the upper portion of wooden Handle  301  to spread outward to width D 4  and urge against the metal inner walls of the eye of hammer head  201  accomplishing metal-to-metal contact. Because height D 2  of Strongback  101  is approximately twice that of the height of Hammer head  201 , and width D 3  is smaller than width D 4 , the spread upper portions of Sides  103  and  104  of Strongback  101  secure hammer head  201  to the assembled Strongback  101  and handle  301 , thus preventing Hammer head  201  from slipping off. The lower portions of metal sides  103  and  104  that now protrude downward from the bottom edge of hammer head  201  along the front and back edges of handle  301  also provide overstrike metal surfaces giving overstrike protection to the upper portion of handle  301 . The overstrike surfaces prevent damage to wooden handle  301  in the event of a user missing the target for which the strike of the hammer is intended. 
     FIG. 5 a  is a three-dimensional view of a strongback according to an alternative embodiment of the present invention. Strongback  501  is provided having an upper portion  502  similar in shape, function and composition to that of Strongback  101  of FIG. 1 a , but with a height equal to that of the eye of a conventional hammer head. Lower portion  503  is a web portion rotated 90 degrees in relation to upper Portion  502 . Lower Portion  503  can be fabricated and attached to upper Portion  502  by brazing, welding or by some other means, or as an integral part of Strongback  501 , twisted or bent 90 degrees. Threaded Holes  504  are provided in this embodiment as means for an alternate method of attachment to a handle such as Handle  301  of FIG. 4 b . In other alternative embodiments the number of Holes  504  can vary, as can the shape, location or size. 
     FIG. 5 b  is a top view of a hammer handle fashioned to be used with the strongback of FIG. 5 a . Handle  301  is shown in this view to have a slot  304  and shoulders  302  as in FIG. 3 c  but with a cross slot  505  provided to accommodate lower Portion  503  of Strongback  501  when inserted down into Handle  301 . To allow accommodation of Strongback  501 , cross slot  505  is cut, milled or otherwise fashioned into Handle  301  to a depth equal to the overall height of Strongback  501  allowing for the complete insertion of Strongback  501  into handle  301 . 
     FIG. 5 c  is a side view of Strongback  501  of FIG. 5 a , Handle  301  of FIG. 5 b  and hammer head  201  of FIG. 2 assembled together according to an alternative embodiment of the present invention. Wedges  401  are shown forcibly inserted and spreading the sides of Strongback  501  as in FIG. 4 b . Metal Caps  506  and  507  are provided in this embodiment to provide protection to handle  301 . Although no detail is given in this view, it can be assumed Caps  506  and  507  have holes drilled or bored completely through, as well as holes drilled or bored completely through Handle  301 , holes positioned to coincide with the location of holes  504  of Strongback  501 , thus allowing accommodation of fasteners  508 . Fasteners  508  in this embodiment can be standard threaded bolts inserted through the holes of cap  506  or  507 , through the holes of handle  301  and fastened by screwing the threaded end of fastener  508  into a corresponding threaded hole in portion  503  of strongback  501 . In alternative embodiments the fasteners used can vary greatly in form or number, as can the location of holes through which they pass and the method of securing the fasteners once inserted. 
     FIG. 6 is a simplified view of a metal strongback according to another alternative embodiment of the present invention assembled with a conventional hammer head. Many details have been omitted from this view in order to provide a clearer view of the subject matter of this embodiment. Strongback  601  is provided being similar in size and shape to Strongback  101  of FIG. 1 a , but with the addition of Shoulders  602  located on opposite ends to provide an interface with, and support to the bottom edge of a conventional hammer head as shown. In another alternative embodiment a strongback similar to that of FIG. 1 a  but with a shorter height that is equal to that of the eye of a Hammer head  201  may be used. In this embodiment, because of the shorter height, overstrike protection is not provided nor is a hole such as hole  106 , or a fastener such as Fastener  402 . The method of securing a hammer head to a handle in this embodiment is accomplished solely by the insertion of wedges as in FIG. 4 b , thereby spreading the top portion of metal Strongback  601  against the metal surface of the eye of a hammer head similarly to methods previously described. 
     FIG. 7 a  is a broken side view of a strongback system with hammer handle according to another alternative embodiment of the present invention. Metal Plates  703  and  704  are provided in this embodiment being equal to each other in size and shape, and having Holes  708  and  710  passing completely through the bottom portion, holes through which a fastener such as Fastener  706  can pass. Fastener  706  in this embodiment is a standard 2-piece assembly comprising of a threaded bolt as a first piece that is inserted and screwed into the female threaded hole of a cylindrically shaped second piece at the opposite end of the assembly. The type of fastener used however can vary greatly in other alternative embodiments. For example, a standard nut and bolt commonly known in the art could be used, as could a screw or some other similar fastening device. 
     Hammer Handle  711  is provided in this embodiment as similar in outward shape and appearance to that of Handle  301  of FIG. 3 a , but with some distinct differences. Handle  711  has a Hole  709  passing completely through Handle  711  and having a diameter sufficient to accommodate a fastener such as Fastener  706 . Hole  709  can also have varying diameters and other properties to accommodate different types of fasteners in other alternative embodiments of the present invention. A V-shaped Slot  713  can be seen in this view cut into the upper portion of Handle  711 . The purpose of Slot  713  in this embodiment is to accommodate a securing wedge used when attaching a hammerhead, and is described and depicted below in greater detail. 
     FIG. 7 b  is a broken front view of the hammer handle of FIG. 7 a . In this view the width and orientation of notch  713  can be seen more clearly, as can the centered location of Hole  709 . Surface  717  is provided having a surface area roughly equal to the dimensions of the bottom surface of Plate  703  so as to provide an even and flat surface on which Plate  703  will rest when secured. Although it is not shown in this view a surface identical to Surface  717  is provided at the opposite side of Handle  711  to accommodate the placement and securing of Plate  704 . 
     FIG. 7 c  is a broken side view of the components of FIG. 7 a  secured to a conventional hammerhead according to an embodiment of the present invention. Plates  703  and  704  attach to Handle  711  using Fastener  706  inserted through holes previously described. The assembly described above is then inserted up through the eye opening of a conventional hammerhead such as Hammerhead  723  as shown. Wedge  720  is provided in this embodiment to complete securing the assembled components described above. Wedge  720  is urged down into Slot  713  until fully seated and the top edge of Wedge  720  is flush with the top edges of the assembled handle  711  and hammerhead  723 . The shape and diameter of wedge  720 , being similar to that of Slot  713  provides a snug fit once inserted. As Wedge  720  is driven down into Notch  715 , the angled sides of Wedge  720 , wider at the top edge than at the bottom edge, make contact with the inner edges of Plates  703  and  704  driving them in an outward direction causing the outer edges of Plates  703  and  704  to urge against the inner walls of the eye of hammerhead  723 , thereby securing hammerhead  723  to the remaining assembled components. In some embodiments spot-welds may be used at points  725  to secure each end of fully inserted wedge  720  to the inner edges of plates  703  and  704 , plates  703  and  704  being held in the forced outward position. 
     FIG. 8 a  is a broken side view of a hammerhead and handle as used with a strongback and securing wedge according to another alternative embodiment of the present invention. In this simplified view metal plates  805  and  806  are provided being similar in size and positioned according to the embodiment represented in FIG. 7 c , but having notches  809  cut, forged or fashioned by some other means into the inner sides near the top of each plate. Metal plates  805  and  806  are fastened to Handle  711  and the assembly is then inserted up into hammerhead  723 , similarly to the components of FIG. 7 c , until flush with the top edge of hammerhead  723 . Wedge  801  is provided in this alternative embodiment being similar in size in shape to Wedge  720  of FIG. 7 c  but with protrusions  802  positioned on each opposite end of wedge  801  and having outer dimensions similar to the inner dimensions of notches  809  of plates  805  and  806 . 
     Once the assembled handle  711  and Plates  805  and  806  are fully inserted up into hammerhead  723 , wedge  801  is inserted down, in the direction shown, into slot  713  until fully&#39;seated, similarly to wedge  720  of FIG. 7 c . During downward insertion of wedge  801  the inner edges of plates  805  and  806  are urged outward by the force of the angled sides of wedge  801  urging the outer edges of plates  805  and  806  against the inner walls of hammerhead  723  as in FIG. 7 c.    
     FIG. 8 b  is a broken side view of the components of FIG. 8 a  assembled according to an embodiment of the present invention. Wedge  801  is shown in this view fully inserted into slot  713 . Once wedge  801  is fully inserted, protrusions  802  fill the void created by notches  809  and snap securely into place by the resilient tendency of plates  805  and  806  to remain in the unforced inward position. With wedge  801  in the locked position, the outer edges of plates  805  and  806  are forced against the inner walls of hammerhead  723  thereby securing the components together as in FIG. 7 c , but also allowing a user to remove or replace wedge  801  if required. 
     FIG. 9 a  is a side view of a strongback according to another alternative embodiment of the present invention. Strongback  901 . is provided in this embodiment being somewhat similar in size and shape to Strongback  101  of FIG. 1 a  but having several distinct differences. A singular notch  903  is provided in this embodiment to accommodate the insertion of a securing wedge shown later in greater detail. Notch  903  also has a vertical dimension similar to that of dimension D 1  of FIG. 1 a , but has a shape more rectangular in nature. An enlarged circular opening is positioned at the bottom of notch  903  allowing for easier insertion and less resistance when a securing wedge is inserted. Sides  905  and  906  are provided in this embodiment being positioned on the outer edges of strongback  901  but having curved inner edges instead of the flat inner edges of strongback  101 , thereby increasing the strength of the interface between the web and sides when the outward forces are created by the insertion of a securing wedge. Serrations  908  are cut, welded or fashioned by some other means into the top outer edges of sides  905  and  906  providing an improved hold on the inner walls of the eye of a hammerhead once a wedge is inserted. Hole  909 , similar in size and position to hole  106  of FIG. 1 a , is provided in this embodiment to allow for the use of a fastening device. 
     FIG. 9 b  is a broken top view of the strongback of FIG. 9 a , assembled with a hammerhead and handle according-to an embodiment of the present invention. This view shows strongback  901  assembled with a handle  914  and a hammerhead  723  prior to insertion of a wedge. Handle  914  is provided in this embodiment with a slot  916  cut across the center into the top to a depth approximately equal to that of dimension D 1  of FIG. 1 a . This dimension however, can vary in different embodiments. The purpose of slot  916  is to accommodate a securing wedge similar to previously described. The rounded shape of sides  905  and  906  can be clearly seen in this view. 
     FIG. 9 c  is a broken section view of the assembled components of FIG. 9 b  with a securing wedge and fastener according to an embodiment of the present invention. A section view taken along line A—A of FIG. 9 b  shows greater detail of the components as assembled according to this embodiment. Wedge  918  is provided that, when driven down in the direction indicated into Slot  903 , creates an outward force causing the sides of strongback  901  to urge against the inner walls of the eye of hammerhead  723 , thereby securing the components together similarly to methods previously described, with serrations  908  enhancing the grip. In some embodiments matching serrations may be provided on the inner surface oft the eye of the hammerhead. Fastener  920  in this embodiment is a standard nut and bolt but can vary greatly in other alternative embodiments. 
     FIG. 10 a  is a side view of a strongback according to another alternative embodiment of the present invention. Strongback  11  is provided in this embodiment being somewhat similar in size and shape to strongback  901  of FIG. 10 a  but having a singular notch  13  creating a void having a rounded shape. The inner walls of the rounded void are threaded to accept a screw-type wedge that is described below in greater detail. Strongback  11  has sides  19  and  20  being similar in size, shape and location to those of strongback  901  but without serrations at the top of the outer edges. 
     FIG. 10 b  is a broken top view of the strongback of FIG. 10 a , assembled with a hammerhead and handle according to an embodiment of the present invention. In this simplified view strongback  11  is shown assembled with a handle  27  and a hammerhead  25  prior to the insertion of a wedge. Although not shown in this view, handle  27  is provided in this embodiment having a slot similar to Slot  304  of handle  301  of FIG. 3 b , extending down into handle  27  to a depth equal to the length of strongback  11 . Hammerhead  25  is provided having serrations  29  at both opposite ends of the eye of hammerhead  25  positioned near the top edge. The purpose of serrations  29  is to provide an improved grip between the outer edges of Sides  19  and  20  and the inner walls of the eye of hammerhead  25  once Sides  19  and  20  have been spread outward by the insertion of a wedge. The rounded void created by notch  13  can be seen in this view, as can the shape of sides  19  and  20 . 
     FIG. 10 c  is a broken section view of the components of FIG. 10 b  used with a wedge-screw according to an embodiment of the present invention. A section view taken along line B—B of FIG. 10 b  shows greater detail of the components as assembled according to this embodiment. Screw wedge  31  is provided being similar in form to a standard threaded screw and having a diameter slightly larger than that of the rounded void created by notch  13 . Screw wedge  31  is inserted down in the direction indicated into the rounded, threaded void of slot  13 . When screw wedge  31  is screwed down into threaded notch  13  an outward force is created causing the sides of strongback  11  to urge outward to dimension D 4  against the inner walls of the eye of hammerhead  25 , thereby securing the components together similarly to methods previously described, with serrations  29  enhancing the grip. Although not shown in this view, strongback  11  can be secured to handle  27  using various fasteners such as previously described. 
     FIG. 11 a  is a side view of a securing wedge according to another alternative embodiment of the present convention. Wedge  35  is provided having a notch  37  similar in size and shape to n 903  of strongback  901  of FIG. 9 a . Serrations  39 , provided as a means for improving the grip between the assembled and secured components, are positioned at both opposite edges of wedge  35 . 
     FIG. 11 b  is a broken top view of the securing wedge of FIG. 11 a , assembled with a hammer handle, head and strongback system according to an embodiment of the present invention. In this simplified view wedge  35  is shown assembled with a handle  41  and a hammerhead  723  prior to the insertion of a wedge. Although not shown in this view, handle  41  has a slot extending down into handle  41  to a depth equal to the vertical height of wedge  35 . Metal plates  45  and  46  are provided in this embodiment being similar in size and shape to plates  703  and  704  of FIG. 7 a  and are assembled with handle  41  similarly. 
     FIG. 11 c  is a broken section view of the assembled components of FIG. 11 b  with a securing wedge and fastener according to an embodiment of the present invention. A section view taken along line C—C of FIG. 11 b  shows greater detail of the components as assembled according to this embodiment. Wedge  47  is provided being similar in size and shape to wedge  918  of FIG.  9   c , having a width slightly greater than the opening of notch  37 . Wedge  47  is inserted down in the direction indicated into notch  37  of wedge  35 , spreading this serrated sides outward to dimension D 4 , thereby securing the components together similarly to methods previously described, with serrations  39  enhancing the grip. In this embodiment plates  45  and  46  are secured to handle  41  using a fastener  706  previously described, but the type of fastener used can vary greatly in other alternative environments. 
     It will be apparent to a worker of ordinary skill that there are many alterations that may be made in the embodiments described herein without departing from the overall spirit and scope of the present invention. For these reasons the invention should be afforded the broadest possible scope limited only by the claims that follow.
A striking tool having a handle engaged in an eye in a head uses a metal strongback unit engaged in a slot the handle to secure the handle in the eye of the head. The metal strongback unit has openings in a web that fits in the slot in the handle that allow wedges to be driven into the handle in a manner that both the handle end and the web of the strongback unit are spread. Metal of the strongback unit urges against an inside surface of the head in the eye to form a secure fit. In a preferred embodiment the strongback unit has metal sides that may extend below the head and provide metal surfaces for overstrike protection.