Abstract:
A striking tool having a handle and a head attached to the handle. The head defines a front end and a back end. A trampoline plate is attached to the head at the front end. The trampoline plate deflects inward toward the back end and rebounds in a direction away from the back end when the trampoline plate strikes an object. In a preferred embodiment, the striking tool is a hammer and the handle is fabricated by welding together matching molded sheet aluminum handle halves. A receiving nut is welded at a top end of the handle and a hammer head is attached to the handle with a bolt threaded through the receiving nut. In this embodiment the aluminum sheet is only approximately 0.063 inches thick so the hammer handle is very light. A rigid rib that extends through the hollow portion of the hollow handle provides additional strength.

Description:
[0001]    This application is a continuation-in-part application of Serial No. 09/790,431 filed Feb. 2, 2001. 
     
    
     
         [0002]    The present invention relates to striking tools, and in particular to heads for striking tools.  
         BACKGROUND OF THE INVENTION  
       Prior Art Hammers  
         [0003]    Striking tools are extremely well known. Prehistoric man knew how to use a club as a tool and as a weapon. As technology developed, the sophistication of striking tools also developed. The hammer was eventually invented and is very common in modem society. Hammers are found in a majority of households in developed countries and are also commonly used by construction companies. However, hammer technology has not changed much since they were invented many centuries ago. Most hammers utilized today, as in the past, have wooden handles and solid steel hammer heads. Wooden handles tend to resonate when in use. The resultant vibration can be fatiguing to the user. Also, solid steel heads tend to be heavy and can cause fatigue to the user after repeated usage.  
         Monocoque Structure  
         [0004]    A monocoque structure is one in which the skin absorbs all or most of the stresses to which the structure is subjected. Because the skin absorbs all or most of the stresses, a monocoque structure can be strong as well as lightweight. Recently, for example, aluminum lightweight monocoque bicycle frames have become very popular for mountain bikes because they provide a strong and stiff, yet lightweight structure.  
         Trampoline Effect  
         [0005]    The trampoline effect (also known as “spring-like effect”) is a term that has recently been applied to certain types of golf club heads. A golf club head that utilizes the trampoline effect has a face plate that deforms when the plate strikes the ball. Behaving like a spring, the face plate rebounds to give the ball a higher launch velocity. For example, FIG. 27 shows club head  400  moving towards golf ball  402 . Club head  400  has hollow chamber  404  covered by thin face plate  406 . FIG. 28 shows club  400  after it has impacted golf ball  402 . The collision between ball  402  and club  400  has caused face plate  406  to deform inward. FIG. 29 shows ball  402  leaving club  400 . Acting as a spring, face plate  406  has rebounded adding extra velocity to ball  402 .  
           [0006]    A golf club that effectively utilizes the trampoline effect can have a very high coefficient of restitution. The coefficient of restitution “e” for the club is calculated as e=v out /v in . The coefficient of restitution of a club can be calculated by holding the face plate of the club stationary. A golf ball is then launched at the face plate at velocity v in . The golf ball then rebounds from the face plate with velocity v out . It has been shown that the trampoline effect increases the launch velocity (v out ) of the golf ball.  
           [0007]    Golf clubs that utilize the trampoline effect have recently been subject to close scrutiny by the U.S. Golf Association (USGA). In recognition of the added velocity achieved by the trampoline effect and in the USGA&#39;s resolve not to permit technology to overwhelm the game, the USGA has gone so far as to designate certain golf clubs that utilize the trampoline effect “illegal”. As of Jun. 25, 2001, the USGA has examined more than 1000 golf clubs to determine compliance with the spring-like effect standard and has identified 38 clubs that are non-conforming. The USGA considers a club non-conforming if it has a coefficient of restitution greater than 0.83 when impacting a golf ball at a velocity of 160 ft/sec.  
           [0008]    What is needed is a better striking tool.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention provides a striking tool having a handle and a head attached to the handle. The head defines a front end and a back end. A trampoline plate is attached to the head at the front end. The trampoline plate deflects inward toward the back end and rebounds in a direction away from the back end when the trampoline plate strikes an object. In a preferred embodiment, the striking tool is a hammer and the handle is fabricated by welding together matching molded sheet aluminum handle halves. A receiving nut is welded at a top end of the handle and a hammer head is attached to the handle with a bolt threaded through the receiving nut. In this embodiment the aluminum sheet is only approximately 0.063 inches thick so the hammer handle is very light. A rigid rib that extends through the hollow portion of the hollow handle provides additional strength. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 shows a cut out handle side.  
         [0011]    [0011]FIG. 2 shows a cut out rib.  
         [0012]    [0012]FIG. 3 shows a cut out handle bottom piece.  
         [0013]    [0013]FIG. 4 shows a sheet of aluminum with cut out pieces.  
         [0014]    [0014]FIG. 5 shows a flat handle side mounted on a mold.  
         [0015]    [0015]FIG. 6 shows a formed handle side mounted on a mold.  
         [0016]    [0016]FIG. 7 shows another formed handle side mounted on a mold.  
         [0017]    [0017]FIG. 8 shows another flat handle side mounted on a mold.  
         [0018]    [0018]FIG. 9 shows a formed handle side mounted on a contoured trim support piece.  
         [0019]    [0019]FIG. 10 shows aligned pieces.  
         [0020]    [0020]FIG. 11 shows a side view of aligned pieces.  
         [0021]    [0021]FIG. 12 shows a handle.  
         [0022]    [0022]FIG. 13 shows a perspective view of a handle.  
         [0023]    [0023]FIG. 14 shows a preferred embodiment of the present invention.  
         [0024]    [0024]FIG. 15 shows a perspective view of a handle with a nut inserted.  
         [0025]    [0025]FIG. 16 shows a perspective view of a handle with a nut welded.  
         [0026]    [0026]FIG. 17 shows an exploded view of a preferred embodiment of the present invention.  
         [0027]    [0027]FIG. 18 shows a top view of a preferred embodiment of the present invention.  
         [0028]    [0028]FIG. 19 shows a side view of a preferred embodiment of the present invention.  
         [0029]    [0029]FIG. 20 shows another preferred embodiment of the present invention.  
         [0030]    [0030]FIG. 21 shows a top view of another preferred embodiment of the present invention.  
         [0031]    [0031]FIG. 22 shows another preferred embodiment of the present invention.  
         [0032]    [0032]FIG. 23A shows a threaded insert.  
         [0033]    [0033]FIG. 23B shows another preferred embodiment of the present invention.  
         [0034]    [0034]FIG. 24 shows a long rib.  
         [0035]    [0035]FIG. 25 shows aligned pieces.  
         [0036]    [0036]FIG. 26 shows a side view of the aligned pieces.  
         [0037]    FIGS.  27 - 29  show a sequence illustrating the operation of a trampoline plate on a golf club head.  
         [0038]    [0038]FIG. 30 shows a preferred hammer having a head with a trampoline plate.  
         [0039]    [0039]FIG. 31 shows an exploded view of the head shown in FIG. 30.  
         [0040]    FIGS.  32 - 34  show front views of some of the components shown in FIG. 31.  
         [0041]    [0041]FIG. 35 shows another preferred head with trampoline plate.  
         [0042]    FIGS.  36 - 40  show a sequence illustrating the operation of the preferred hammer shown in FIG. 30. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0043]    Preferred embodiments of the present invention are hereinafter described by reference to the drawings.  
       Cutting Pieces From Aluminum Sheet  
       [0044]    In a preferred embodiment of the present invention, flat handle sides  1 , rib pieces  2 , and handle bottom pieces  3  are cut from 4′×8′ sheet  4 , as shown in FIG. 4. In the preferred embodiment, flat handle sides  1 , rib pieces  2 , and handle bottom pieces  3  are cut using a water jet saw. Preferably, sheet  4  is 6061 aluminum and is approximately 0.063 inch thick. Detailed views of flat handle side  1 , rib piece  2  and handle bottom piece  3  are shown in FIGS.  1 - 3 . In a preferred embodiment, flat handle side  1  is approximately 17 ½ inches long, rib piece  2  is approximately 2⅜ inches long and handle bottom piece  3  is approximately 2⅛ inches from top to bottom as shown in FIG. 3.  
       Forming Handle Sides  
       [0045]    As shown in FIG. 5, flat handle side  1  is laid on contoured mold  6 A. Flat handle side  1  is held in place on contoured mold  6 A by nails  7  aligned against extension  9  and indentation  10  (see FIG. 1). Contoured mold  6 A with flat handle side  1  is then placed inside a hydraulic ram press and approximately 40,000 psi of pressure is imparted to the top of flat handle side  1 . This pressure causes flat handle side  1  to assume the contoured shape of the top of contoured mold  6 A. In a preferred embodiment, the contoured shape of the top of contoured mold  6 A is similar to the shape of half of a hammer handle. As shown in FIG. 6, after contoured mold  6 A has been removed from the hydraulic ram press, flat handle side  1  has been formed into formed handle side  8 A.  
         [0046]    Then, a second flat handle side  1  is flipped over and laid on contoured mold  6 B as shown in FIG. 7. In a fashion similar to that described above, contoured mold  6 B is placed in a hydraulic ram press and so that flat handle side  1  is formed into formed handle side  8 B, as shown in FIG. 8.  
       Trimming Handle Edges  
       [0047]    The edges of formed handle sides  8 A and  8 B may be rough due to slight imperfections during the cutting of flat handle sides  1 . Therefore, in a preferred embodiment, the edges of formed handle sides  8 A and  8 B are trimmed so that they will fit together better. FIG. 9 shows formed handle side  8 B laid on top of contoured trim support piece  11 . Contoured trim support piece  11  has trough  12 . To trim the edges of formed handle side  8 B a router bit is set at the proper level to run along trough  12 . The router bit is then run along trough  12 . The router bit will cut off imperfections in the edges that extend into trough  12 .  
       Aligning and Joining Pieces Together  
       [0048]    [0048]FIG. 10 shows a front exploded view and FIG. 11 shows a corresponding side view of the preferred embodiment. Formed handle sides  8 A and  8 B, rib piece  2  and handle bottom piece  3  are aligned as shown. In the preferred embodiment, rib piece  2  has extensions  12  and  13  (also shown in FIG. 1). Extensions  12  and  13  aid in the alignment of rib piece  2  with edge  17  of formed handle side  8 A. The individual aligning rib piece  2  can look at extensions  12  and  13  to realize to realize that the side of rib piece  2  containing extensions  12  and  13  should be the side of rib piece  2  aligned with edge  17 . Handle bottom piece  3  is then properly aligned with the bottom of formed handle sides  8 A and  8 B by aligning cut-out portions  20  with extensions  9 . In the preferred embodiment, handle bottom piece  3  is also by extensions  9  when it is pressed up against the bottom of formed handle sides  8 A and  8 B.  
         [0049]    After formed handle sides  8 A and  8 B, rib piece  2  and handle bottom piece  3  are properly aligned, they are then clamped together. They are then tacked and welded together so that they form monocoque handle  15  as shown in FIG. 12. In the preferred embodiment, the top of monocoque handle  15  is cut so that it is flat as shown in FIG. 13.  
       Attaching the Hammer Head to the Handle Bolting the Head to the Handle  
       [0050]    In the first preferred embodiment, head  25  is bolted to handle  26 , as shown in FIGS.  17 - 19 . Rectangular cuts are made as shown in formed handle sides  8 A and  8 B and in rib piece  2  to accommodate inserted nut  30 , as shown in FIG. 15. Nut  30  is then welded to handle  26  as shown in FIG. 16.  
         [0051]    [0051]FIG. 17 shows a side exploded view, FIG. 18 shows a top view, and FIG. 19 shows a side view of the second preferred embodiment. Conventional hammer head  25  with contoured opening  27  is lowered onto handle  26 . Washer  32  is then inserted inside the top of opening  27  and hex bolt  34  is threaded onto nut  30  and tightened.  
         [0052]    There are several advantages to the first preferred embodiment. One advantage is that it is much quicker to bolt hammer head  25  to handle  26  than it would be to glue it. Another advantage is that if damage is done to handle  26  or head  25 , the head could be easily unbolted and the damaged part could be replaced without having to replace the entire hammer. Another advantage is that a user of the hammer can have a hammer kit that encompasses a variety of handle shapes and designs and head shapes and designs that can be interchanged with each other to create a custom tool to fit the user&#39;s need at any given moment.  
       Gluing the Head  
       [0053]    In the second preferred embodiment, head  25  is glued to the top of handle  15  as shown in FIG. 14. Although gluing the head is a fairly simple process, it is somewhat time consuming. It takes a worker approximately 15 minutes to complete the gluing process. Another disadvantage of gluing is that once head  25  is glued to handle  15 , it is extremely difficult to remove it. Therefore, if there is damage done to either head  25  or handle  15 , the entire hammer needs to be replaced.  
       Third Preferred Embodiment  
       [0054]    A third preferred embodiment is shown in FIGS. 20 and 21. In the third preferred embodiment, head  40  is cut so that the utilization of washer  32  (FIGS.  17 - 19 ) is unnecessary. There is a small hole in the top of head  40  through which bolt  34  is inserted. Bolt  34  is then threaded through nut  30  and tightened as described above.  
       Fourth Preferred Embodiment  
       [0055]    In the fourth preferred embodiment shown in FIG. 24, rib piece  300  is much longer than rib piece  2  shown in FIG. 2. Rib piece  300  is approximately the same length as formed handle sides  302 A and  302 B, as shown in FIG. 25. However, rib  300  does not need to be as thick as handle sides  302 A and  302 B. In the preferred embodiment, rib  300  is approximately 0.050 inches thick and handle sides  302 A and  302 B are approximately 0.063 inches thick. By making rib piece  300  the approximate length of formed handle sides  302 A and  302 B, rib piece  300  is able to absorb greater amounts of stress while the handle is being used. This makes the handle less likely to snap than the embodiment shown in FIGS.  10 - 11 .  
         [0056]    After rib piece  300  has been cut, it is aligned with formed handle sides  302 A and  302 B and handle bottom piece  304  as shown in FIG. 25. After alignment the pieces are clamped together. They are then tacked and welded together. In the preferred embodiment, rib piece  300  is cut so that its edges extend beyond formed handle sides  302 A and  302 B, as shown in FIG. 26. The edges of rib piece  300  serve as filler metal during the welding process.  
       Varying Cross Section Area  
       [0057]    By first cutting out handle sides, forming the handle sides into formed handle sides and then welding the formed handle sides together, a contoured handle having cross section areas that vary along the length of the handle can be made. Consequently stiffness can be added to the handle at areas subject to high stress and taken away from areas of the handle that are not subject to high stress. For example, as shown in FIG. 14, handle  15  is wider towards the top of the handle at section  452  than it is at the grip of handle at section  450 . This is because the handle is subject to greater stress at section  452  than it is at section  450 .  
       Utilization of Rib  
       [0058]    Also, in the preferred embodiments discussed above, a rib is used to provide extra stiffness to the handle. FIG. 10 shows a short rib  2  and FIG. 25 shows a long rib  300 . Utilization of the rib contributes to the overall stiffness and strength of the handle. By utilizing a contoured hollow handle and adding a rib for support the strength and stiffness characteristics of the handle are optimized. Also, because the handle is made out of a low density material such as aluminum the handle is extremely lightweight. The density of aluminum is approximately 2.7 g/cm 3 . This contrasts sharply with steel that has a density of approximately 7.9 g/cm 3 . For example, the weight of Applicant&#39;s handle shown in FIGS.  10 - 13  is approximately 7 ounces.  
       Hammer Head with Trampoline Plate  
       [0059]    [0059]FIG. 30 shows a fifth preferred embodiment in which hammer head  410  has trampoline plate  412 . Trampoline plate  412  deforms inward when it strikes a nail. Then, behaving like a spring, trampoline plate  412  rebounds outward, driving the nail with extra force.  
         [0060]    The operation of hammer head  410  is seen in more detail by referring to FIGS.  36 - 40 .  
         [0061]    In FIG. 36, hammer head  410  is being driven downwards towards nail  414 , which is slightly imbedded in wood.  
         [0062]    In FIG. 37, hammer head  410  has made contact with nail  414 . The impact of hammer head  410  against nail  414  has caused trampoline plate  412  to deform inward. Nail  414  has been moved slightly further into the wood as a result of the impact.  
         [0063]    In FIG. 38, behaving like a spring, trampoline plate  412  has partially rebounded. Consequently, nail  414  has been driven further into the wood.  
         [0064]    In FIG. 39, trampoline plate  412  has fully rebounded and nail  414  has been driven even further into the wood.  
         [0065]    In FIG. 40, hammer head  410  has been raised.  
         [0066]    Preferably, the sequence illustrated in FIGS.  36 - 40  is repeated until the nail has been fully driven into the wood.  
       Fabricating the Hammer Head  
       [0067]    [0067]FIG. 31 shows an exploded view of hammer head  412 . In the fifth preferred embodiment, hammer head  412  is fabricated from steel. Base section  416  has rounded support section  418  at its end. Preferably, hollow tube section  420  is welded to support section  418 . Also, preferably trampoline plate  412  is welded to hollow tube section  420 . In the preferred embodiment, trampoline plate  412  is approximately ⅛ inch thick. End views of support section  418 , hollow tube section  420  and trampoline plate  412  are shown in FIGS.  32 - 34 , respectively.  
         [0068]    Alternatively, FIG. 35 shows a sixth preferred embodiment in which hammer head  430  has been cast from steel utilizing a mold to form trampoline plate  432 .  
       Trampoline Effect for the Hammer Head  
       [0069]    The greater the trampoline effect, the greater the amount of energy that is transferred to the nail due to the trampoline effect. The trampoline effect is dependent upon the characteristics of the trampoline plate. For example, a thin trampoline plate will deform and rebound more than a thick trampoline plate. Higher deformation of the trampoline plate may also be achieved by modifying the material by which it is made. For example, high deformation can be achieved by fabricating the trampoline plate from a material having low stiffness and high strength, such as titanium.  
       Effect of Hollow Hammer Head with Trampoline Plate  
       [0070]    A hollow hammer head covered by a trampoline plate is a significant improvement over the prior art. Because the hammer head has a hollowed out section, it weights much less than a solid hammer head made of the same material. This results in a hammer that weights less and is therefore easier to operate and less fatiguing for the user. Also, the trampoline plate improves the efficiency of the hammer. When the hammer head strikes a nail, the trampoline plate deflects inward. Acting as a spring, energy is stored in the trampoline plate and then released when the trampoline plate rebounds. The release of this energy propels the nail forward with greater velocity into the medium into which it is being hammered.  
       Handle Types  
       [0071]    A hammer head having a trampoline plate can be used with a variety of handle types. For example, it can be used with a wood handle or a metal handle. Also, a hammer head having a trampoline plate can be utilized attached to the monocoque handles disclosed in the earlier preferred embodiments.  
       Prototype  
       [0072]    Applicant has actually built a prototype hammer head with trampoline plate similar to the embodiment shown in FIGS.  31 - 34 . In the prototype, the trampoline plate was steel and was approximately ⅛ inch thick. Applicant, then tested the prototype by allowing  6  individuals to use the prototype to hammer a nail into a board. Each individual confirmed that the prototype hammer having a hammer head with trampoline plate was a substantial improvement over a conventional solid steel hammer head.  
         [0073]    While the above description contains many specifications, the reader should not construe these as limitations on the scope of the invention, but merely as exemplifications of preferred embodiments thereof. Those skilled in the art will envision many other possible variations are within its scope. For example, although the above embodiments all showed the utilization of rib for extra strength and stiffness, it would be possible to make the present invention without a rib. For example, by making the skin of the handle thicker, its strength and stiffness would also increase. However, to achieve the same level of strength and stiffness that is achieved by the utilization of a rib, higher amounts of aluminum would need to be added to the skin thickness. Consequently a thick skinned handle without a rib would weight more than a thin skinned handle with a rib, assuming they both had the same strength and stiffness. Also, although the above preferred embodiments showed how a hammer head is bolted into a monocoque handle, it is possible to bolt a hammer head into other types of handles as well. For example, FIG. 22 shows head  40  bolted into solid metal handle  50 . FIG. 23B shows head  40  bolted into threaded insert  334  (FIG. 23A) that has been tapped into the side of solid wood handle  60 . Also, although it was stated in the first preferred embodiment that sheet  4  is  6061  aluminum and is approximately 0.063 inches thick, those of ordinary skill in the art will recognize that other sheet materials and/or other thicknesses could be used as well. For example, sheet  4  could be AZ31B magnesium. Magnesium is even less dense than aluminum (approximately 1.8 g/cm 3 ), however it is also more expensive. Also, although all the above preferred embodiments disclosed a monocoque handle used in conjunction with a hammer head, it would also be possible to utilize the monocoque handle with other types of striking tools. Some of these tools include an ax, a pick-ax, and a mallet. Also, although it was disclosed that pieces are cut from sheet  4  using a water jet saw, it would also be possible to cut the pieces using other devices, such as a shearing dye, a laser or a band saw. Also, although it was disclosed how formed handle sides  8 A and  8 B are formed using a hydraulic ram press, it would also be possible to form the handle sides using other methods, such as utilizing a matched dye set. Also, although it was disclosed above that trampoline plate  412  is approximately ⅛ inch thick, the thickness could easily be modified. Thicker plates will be less likely to puncture, but they will not deform as much. Thinner plates will deform and rebound to a greater degree, but will be more likely to puncture. Also, the trampoline plate could be fabricated from a variety of materials other than steel and titanium as discussed above. Also, although the fifth preferred embodiment disclosed utilizing a hammer head having a trampoline plate, other striking tools besides a hammer can effectively utilize the trampoline plate. For example, a mallet could also include a mallet head that has a trampoline plate. Accordingly the reader is requested to determine the scope of the invention by the appended claims and their legal equivalents, and not by the examples which have been given.