Patent Publication Number: US-7584773-B2

Title: Wood-splitting tool

Description:
TECHNICAL FIELD 
   The present invention relates to the field of wood-splitting tools, and, more particularly, a wood-splitting tool incorporating features improving penetration, engagement/traction, splitting, and efficiency properties of the tool. 
   BACKGROUND 
   Many tools have been developed over the years to enable the splitting of wood, such as logs or timber, with the aid of an impact tool, such as a mallet or hammer. Although some of these tools have provided adequate results, many of these tools suffer from several chronic problems or drawbacks. For instance, many of these tools are difficult to drive into a piece of wood and have mediocre penetration properties. Additionally, many tools disengage the wood piece too easily and accidentally “pop out” of the wood piece when the tool is impacted with a hammer or mallet, thereby creating a potential safety hazard. Many of these tools are designed with a primary emphasis on splitting the wood piece with a wedge action, with minimal cutting or penetrating action, which contributes to this disengagement problem. 
   The present invention addresses these and other concerns, and generally provides an improved wood-splitting tool, as will become apparent from the following written description, drawings, and claims. 
   SUMMARY OF THE INVENTION 
   The present invention is a wood-splitting tool that provides, among other things, increased pre-splitting penetration into a piece of wood, improved traction in the piece of wood after initial penetration, improved engagement with the piece of wood, and overall increased wood-splitting efficiency. 
   In accordance with the principles of the present invention, the wood-splitting tool includes a penetration portion having a penetrating end and a wedge portion having an impact end. The penetration portion is configured for penetration into a piece of wood. The penetration portion includes two penetration surfaces diverging from each other at an inclusive angle. The wedge portion includes two wedge surfaces generally contiguous with the diverging penetration surfaces and diverging from each other at an inclusive angle, which is greater than the inclusive angle of the diverging penetration surfaces. The wedge portion is primarily configured to impart a wedge force to the wood. The penetration portion has a length that is greater than half the length of the tool, which allows the tool to penetrate the piece of wood without significantly imparting a wedge force until the tool penetrates deep enough to allow the wedge portion to engage the wood. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a perspective view of a particular embodiment of a wood-splitting tool in accordance with the principles of the present invention. 
       FIG. 2  is a front elevational view of the wood-splitting tool of  FIG. 1 . 
       FIG. 3  is a side elevational view of the wood-splitting tool of  FIG. 1 , illustrating a comparison of length dimensions of the penetration portion and the wedge portion of the wood-splitting tool of  FIG. 1 . 
       FIG. 4  is a partial detail view, in perspective, of the penetrating end of the wood-splitting tool of  FIG. 1 . 
       FIGS. 5-8  are cross-sectional illustrations of the wood-splitting tool of  FIG. 1  engaging a piece of wood in the form a log, each illustration showing one of three stages of engagement between the wood-splitting tool and the log. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   The description that follows describes, illustrates and exemplifies one or more particular embodiments of the present invention in accordance with its principles. This description is not provided to limit the invention to the embodiments described herein, but rather to explain and teach the principles of the invention in such a way to enable one of ordinary skill in the art to understand these principles and, with that understanding, be able to apply them to practice not only the embodiments described herein, but other embodiments that may come to mind in accordance with these principles. The scope of the present invention is intended to cover all such embodiments that may fall within the scope of the appended claims, either literally or under the doctrine of equivalents. 
   It is noted that in the description and drawings, like or substantially similar elements may be labeled with the same reference numerals. However, sometimes these elements may, but not always, be labeled with differing numbers in cases where such labeling may facilitate a more clear description. Additionally, the drawings set forth herein are not necessarily drawn to scale, and in some instances proportions may have been exaggerated to more clearly depict certain features. 
   In accordance with the principles of the present invention,  FIGS. 1-3  show a wood-splitting tool  10 . The tool  10  is generally elongated and defines an overall length, a penetration portion  12  and a wedge portion  14 . The tool  10  includes a penetration end  16  adjacent the penetration portion  12  and an impact end  18  adjacent the wedge portion  14 . The impact end  18  is generally configured to accept an impact force from an impact tool, such as a hammer, mallet, or other tool known in the art to impart an impact force. The penetration portion  12  is generally configured to primarily penetrate into a piece of wood. The wedge portion  14  is generally configured to primarily impart a wedge force to the wood, i.e., a force having a direction that is generally transverse to the length of the tool  10  to facilitate splitting of the wood. 
   Referring to  FIGS. 1-3 , the penetration portion  12  includes two penetration surfaces  22  diverging from each other at an inclusive angle α generally from the penetrating end  16 . In a preferred embodiment, as shown in  FIG. 4 , the penetration end  16  is configured to have a knife-like edge  24 , to facilitate initial penetration into the wood. The knife-like edge  24  technically introduces an angle that is greater than a for a small portion of the length of the penetration portion  12 . Because of this feature, and among other reasons, one of which is for purposes of clarification herein without imparting unnecessary limitation, the penetration surfaces  22  are referred to as diverging from each other at an inclusive angle α generally from the penetrating end  16 . 
   Referring once again to  FIGS. 1-3 , the wedge portion  14  includes two wedge surfaces  26 , which are generally contiguous with the penetration surfaces  22 . As shown in  FIG. 3 , the two wedge surfaces  26  diverge from each other at an inclusive angle β, which is greater than the inclusive angle α of the diverging penetration surfaces  22 , thereby increasing the wedge properties of the wedge portion  14 . In a preferred embodiment, the inclusive angle β of the diverging wedge surfaces  26  is at least 2 times the inclusive angle α of the diverging penetration surfaces  22 . In a preferred embodiment, the inclusive angle α of the diverging penetration surfaces  22  is from about 2 to 10 degrees. In a preferred embodiment, the inclusive angle β of the diverging wedge surfaces  26  is from about 15 to 25 degrees. 
   As shown in  FIG. 3 , the penetration portion  12  has a general length K and the wedge portion  14  has a general length W. The length K of the penetration portion  12  is greater than half the length of the tool  10 , which allows the penetration portion  12  to penetrate the piece of wood without significantly imparting a wedge force until the tool penetrates deep enough to allow the wedge portion  14  to engage the wood. In a preferred embodiment, the penetration portion  12  has a length K that is between about ⅔ to ¾ of the length of the tool  10 . In a preferred embodiment, the penetration portion  12  has a length K of about 8 inches. 
   As best shown in  FIG. 3 , the wedge surfaces  26  are both disposed at a substantially similar distance from the penetrating end  16  of the penetration portion of the tool. This maximizes the wedge force applied to the wood by the wedge portion  14 , since both wedge surfaces  26  will be substantially simultaneously engaging the wood. Additionally, in a preferred embodiment, as shown in  FIG. 2 , each of the wedge surfaces  26  have a width  32  that decreases along a length S of each wedge surface  26  in a direction away from the penetrating end  16  of the tool  10 , i.e., the width of the wedge surfaces taper toward the impact end of the tool  10 . The decreasing width  32  allows the wedge force to be applied to the wood with minimal increase in surface area engagement as the wedge portion  14  further engages the wood. 
   The tool  10  can be formed from any material having properties sufficient to withstand impact forces applied thereto by an impact tool, such as, for example, steel or other metallic tool material. In a preferred embodiment, the tool  10  is made of forged or double-forged tool-grade steel. 
     FIGS. 5-7  illustrate three stages of engagement by the tool  10  with a piece of wood in the form of a log  40 . In  FIG. 5 , the penetrating end  16  of the penetration portion  12  initially engages the log  40 . At this stage, the knife-like edge  24  works to cut into the log  40  and allow initial penetration of the penetration portion  12  into the log  40 . At this stage, the tool  10  can be held in one hand of a user while the other hand can be used to tap the impact end  18  of the tool  10  with an impact tool.  FIG. 6  illustrates an intermediate stage wherein the penetration portion  12  of the tool  10  has significantly penetrated the log  40  with minimal splitting of the log  40 . By primarily penetrating the log  40  at this stage, rather than applying a wedge force for splitting, the tool  10  is allowed to gain traction against wood fibers of the log  40 . Among other things, this prevents the tool from easily disengaging or “popping out” before the log  40  is split. As shown in  FIG. 7 , not until the full length K of the penetration portion  12  completely penetrates the log  40  does the wedge portion  14  engage the log  40 . At this stage, the wedge portion  14  primarily applies a wedge force to the log  40 , rather than further penetration into the log  40 , and the log  40  is easily split. 
   The advantages of the present invention are numerous. For example and without limitation, the present invention allows the tool to penetrate into wood without requiring the wood to begin to split for further penetration. It also increases safety by reducing the possibility of the tool from “popping out” of the wood due to inadequate penetration, and, hence, traction in the wood. Additionally, the increased penetration of the tool before application of the wedge force significantly weakens the wood core, which allows the wood to split with reduced wedge force and more efficiency. Furthermore, the penetration and wedge portions of the tool work together to provide overall improved transfer of energy to the wood and efficiency in terms of energy required to be applied to the tool via strikes with the impact tool. These are just some of the many advantages that may become apparent to one of ordinary skill in the art upon review of the disclosure set forth herein. 
   As previously stated, the foregoing description is not provided to limit the invention to the embodiments described herein. Rather, the scope of the present invention is intended to cover all embodiments that may fall within the scope of the following claims, either literally or under the doctrine of equivalents.