Patent Publication Number: US-9833918-B1

Title: Apparatus for splitting wood into kindling

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional of, and claims the benefit of, U.S. patent application Ser. No. 14/712,739, filed on May 14, 2015, which is a continuation-in-part of, and claims the benefit of, U.S. patent application Ser. No. 13/843,064, filed on Mar. 15, 2013, which is a continuation-in-part of, and claims the benefit of, U.S. patent application Ser. No. 12/507,021, filed on Jul. 21, 2009, which issued as U.S. Pat. No. 8,424,212 on Apr. 23, 2013, all of which are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     Embodiments of the present invention relate to manual tools for splitting or chopping wood. 
     BACKGROUND 
     Hand tools used to cut wood through the ages often have taken the form of an axe, an adz, or a splitting wedge used with a blunt sledge hammer. Each type of tool has features that are useful for different purposes, but each tool also has certain limitations. For example, an axe or hatchet has a metal blade in line with the handle, a useful configuration for efficiently exerting a downward force to split relatively small logs with a single blow. However, if the single blow is not energetic enough to split the wood, the axe may become stuck in the wood. Dislodging an axe stuck in a piece of wood is an awkward, unpredictable, and risky activity. Larger logs benefit from the use of splitting wedges in which a wedge having a sharp blade is separate from a blunt sledge hammer used to safely drive the wedge into the wood with multiple blows. If the wedge gets stuck, a second or even a third wedge may be driven into the same piece of wood to multiply the splitting force. Drawbacks of such a “sledge and wedge” system include the weight of the sledge hammer and suitability for larger pieces of wood as opposed to kindling. An adz is another conventional cutting tool that uses a chisel or gouge-shaped blade for hewing and shaping timber. The adz features an axe blade oriented perpendicular to the handle, similar to a garden hoe, instead of in line with the handle, like a standard axe. Most existing wood-splitting tools are variations of these three well known forms, featuring a variety of different cutting head shapes, handle forms, and methods of attaching the blade to the handle. 
     SUMMARY 
     A novel splitting tool and a specialized chopping block described herein cooperate to enable kindling to be cut from ordinary firewood in an efficient and safe manner with a minimal application of force. The splitting tool applies leverage in addition to downward momentum of the cutting head to split wood. Extra leverage becomes possible with the use of a metal handle integrated with a metal cutting head, the cutting head and handle being formed or attached in a perpendicular configuration similar to an adz. However, the splitting tool differs from a conventional axe or adz in a number of respects. In addition to the all-metal construction, a widening profile of the handle near the cutting head has a unique triangular shape, thereby increasing the amount of leverage that may be applied to the wood. A secondary cutting blade is integrated into the end of the handle near the cutting head to split wood away from the face of the cutting head, thereby preventing the tool from getting stuck in the wood. In addition, the integrated flat top surfaces of the cutting head and the handle near the joint allow the user to drive the cutting head completely into the wood as though the cutting head were splitting wood. 
     The splitting tool is complemented by a specialized chopping block for holding wood in a steady, upright position. The chopping block features a V-shaped recess that is open on one end, allowing the user to slide a kindling log into the recessed platform until it is sufficiently braced, thereby accommodating kindling logs of various diameters. 
     The chopping block also provides resistance to the downward force of the splitting tool during the splitting action. 
     A novel attachment for connecting a handle extension to a striking hand tool having a head, a handle shaft, and an elongate handle extension is also provided. The head has a first dimension along which the head is adapted to transfer striking force and a second dimension, non-parallel to the first dimension, along which the handle shaft extends away from the head The handle extension has an attachment end, a grip end, a top portion and a bottom portion. The attachment comprises a top tang and a bottom tang extending away from the handle shaft nominally in a plane defined by the first dimension and the second dimension of the head. The tangs are spaced from one another in that plane. 
     A top groove is formed in the top portion of the handle extension so as to extend longitudinally from the attachment end toward the grip end of the handle extension for receiving the top tang, and a bottom groove is formed in the bottom portion of the handle extension so as to extend longitudinally from the attachment end toward the grip end of the handle extension for receiving the bottom tang. The spacing between the top groove and the bottom groove is such that the attachment end of the handle extension may be inserted longitudinally into the handle shaft whereby the top tang is disposed in the top groove and the bottom tang is disposed in the bottom groove. At least one fastener is provided for attaching the top tang to the handle extension and the bottom tang to the handle extension. 
     A woodsman&#39;s hatchet is also provided. The woodsman&#39;s hatchet comprises a cutting head and handle, or handle shaft. The cutting head has a primary, or first, cutting blade. A secondary, or second, cutting blade integrated into an end of the handle near the cutting head on the same side of the handle as the first cutting blade. The cutting head also has a third cutting blade at an end of the cutting head opposite the first cutting blade. The first cutting blade is perpendicular to the elongate axis of the handle shaft, and the third cutting blade is perpendicular to the first cutting blade. 
     It is understood that this summary is provided as a means for generally determining what follows in the drawings and detailed description, and is not intended to limit the scope of the invention. The foregoing and other objects, features and advantages of the invention will be readily understood upon consideration of the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a first embodiment of a splitting tool and chopping block system, in accordance with a preferred embodiment. 
         FIG. 2  is a side view of the first embodiment of the splitting tool showing the cutting head, handle, and joints as well as cut lines corresponding to cross sectional views shown in  FIGS. 3-5 . 
         FIG. 3  is a cross-sectional view of the steel handle shaft and rubber grip of the first embodiment of the splitting tool along a cut line  3 - 3 , shown in  FIG. 2 . 
         FIG. 4  is a cross-sectional view of the steel handle shaft of the first embodiment of the splitting tool along a cut line  4 - 4 , shown in  FIG. 2 . 
         FIG. 5  is a cross-sectional view of the steel handle shaft near the cutting head, of the first embodiment of the splitting tool along a cut line  5 - 5 , shown in  FIG. 2 . 
         FIG. 6  is a front view of the cutting head of the first embodiment of the splitting tool. 
         FIG. 7  is a top view of the chopping block shown in  FIG. 1  in accordance with a preferred embodiment. 
         FIG. 8  is a front view of the chopping block shown in  FIG. 1 . 
         FIG. 9  is a cross-sectional view of the chopping block shown in  FIG. 1 . 
         FIG. 10  is a side view of a second embodiment of the splitting tool showing a cutting head including a handle, and a handle extension attached to the cutting head. 
         FIG. 11  is a top view of the second embodiment of the splitting tool shown in  FIG. 10 . 
         FIG. 12  is a front view of the second embodiment of the splitting tool shown in  FIG. 10 . 
         FIG. 13  is a bottom view of the second embodiment of the splitting tool shown in  FIG. 10 . 
         FIG. 14  is an end view of the cutting head with the handle extension removed. 
         FIG. 15  is a perspective view of a third embodiment of a splitting tool having an alternative attachment for connecting a handle extension to the head of a striking hand tool. 
         FIG. 16  is a side, exploded view of the embodiment of a splitting tool shown in  FIG. 15 . 
         FIG. 17  is a side view of the embodiment of a splitting tool shown in  FIG. 15 . 
         FIG. 18  is a top view of the embodiment of a splitting tool shown in  FIG. 15 . 
         FIG. 19  is a bottom view of the embodiment of a splitting tool shown in  FIG. 15 . 
         FIG. 20  is a cross-section of the embodiment of a splitting tool shown in  FIG. 15 , taken along the line  20 - 20  of  FIG. 17 . 
         FIG. 21  is a side view of an embodiment of a mattock employing the attachment shown in  FIGS. 15-20 . 
         FIG. 22  is a side view of an embodiment of a pick axe employing the attachment shown in  FIGS. 15-20 . 
         FIG. 23  is a side view of an embodiment of a hammer employing the attachment shown in  FIGS. 15-20 . 
         FIG. 24  is a perspective of an embodiment of a woodsman&#39;s hatchet employing the attachment shown in  FIGS. 15-20 . 
         FIG. 25  is a side view of the woodsman&#39;s hatchet of  FIG. 24 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
       FIG. 1  shows a perspective view of the two components described herein: a first embodiment of a splitting tool  10 , and a chopping block  12 , shown in approximate proportion to each other. The splitting tool  10  comprises a handle shaft  14 , and, attached perpendicularly to a distal end  16  of the handle shaft  14 , a tapered cutting head  18 . Both handle shaft  14  and cutting head  18  are preferably made of steel and are preferably forged or cast into one continuous steel piece to maximize strength at a joint  19 , though joint  19  generally may be formed by welding, soldering, or another method of attachment. At a proximal end  20  of handle shaft  14 , opposite cutting head  18 , steel handle shaft  14  is preferably partially surrounded by a rubber grip  22 , covering about half the length of handle shaft  14 , the rubber grip  22  providing both user comfort and impact resistance. Proximal end  20  of handle shaft  14  has an oblong profile that tapers along its length toward a mid-section  28  at which the rubber grip  22  ends. 
     Beyond mid-section  28 , toward distal end  16 , the cross section of handle shaft  14  widens near joint  19  to a shape that surrounds a broad, flat, top handle shaft striking surface  30  and a tapered secondary cutting blade  32  on the underside of handle shaft  14  to assist the cutting head  18  in splitting wood. Secondary cutting blade  32  structurally reinforces joint  19  to better withstand the forces generated when prying wood apart. The butt, or top surface, of cutting head  18  is also formed into a flat plane, providing a clean striking surface  34  opposite a primary cutting blade  36 . In a preferred embodiment, striking surfaces  30  and  34  form a single, integrated flat plane. If primary cutting blade  36  should become lodged in the wood (because of the presence of knots, for example), removing cutting head  18  is made easier by the availability of the striking surfaces  30  and  34 . By striking these flat surfaces with a mallet or other weighty object, an additional downward force is supplied to either finish splitting the wood by prying it apart, or to free cutting head  18  for another attempt. 
       FIG. 1  also shows a perspective view of the solid wood rectangular chopping block  12 , having as its principal feature a V-shaped recessed platform  42 , cut from its top surface  44 . According to a preferred embodiment, recessed platform  42  has straight recessed walls  45  and a rounded point  46  opposite an open end  48 . For example, a kindling log may be slid through open end  48 , and wedged into rounded point  46  in an upright position for processing. 
       FIG. 2  shows a side view of splitting tool  10  having three sets of cut lines to demonstrate variations in the cross-sectional profile along the length of handle shaft  14 . According to a preferred embodiment, approximate dimensions of handle shaft  14  include a circumference of about 3 inches, and a total length of about 10 inches, of which a sharp edge on secondary cutting blade  32  extends about three inches from joint  19  toward proximal end  20 . 
       FIGS. 3-5  show specific cross-sectional profiles along cut lines  3 - 3 ,  4 - 4 , and  5 - 5 , respectively, shown in  FIG. 2 .  FIGS. 3 and 4  show that the oblong profile at proximal end  20  is preferably oriented so that its vertical dimension  24  exceeds its horizontal dimension  26 , and that steel handle shaft  14  has a profile in a rounded diamond shape  38 .  FIG. 3  additionally shows that the rubber grip  22  surrounding the proximal end  20  of handle shaft  14  causes the overall form of the handle to have an oval shape  40 . At mid-section  28  of the steel handle shaft  14 , beyond the end of rubber grip  22 , the profile simply comprises the core rounded diamond shape  38 . The cross-sectional profile of steel handle shaft  14  near distal end  16  tapers to a point at the bottom, and the flat top gradually widens toward joint  19 , totaling an elongated triangular shape shown in  FIG. 5 . 
       FIG. 6  is an end view of the four-sided cutting head  18  showing the primary cutting blade  36 , the convex curve of the blade profile having a radius of curvature of about 3 inches. According to a preferred embodiment, cutting head striking surface  34 , opposite primary cutting blade  36  is about 1.75 inches wide and 0.75 inches deep, providing ample surface area for use as a striking surface in conjunction with surface  30  on handle shaft  14 . Cutting head  18  is preferably about 4.75 inches long. The sides of cutting head  18  are contoured in a concave curve having about a 5 inch radius of curvature. As cutting head  18  is driven into the wood, secondary cutting blade  32  on the bottom of the handle opens a second split at a right angle to the main split initiated by primary cutting blade  36  on cutting head  18 . This action exerts transverse shear forces on the wood to enhance the splitting. The mechanical advantage of the secondary cutting blade  32  used as a lever, in cooperation with primary cutting blade  36 , splits apart even hard, dense wood with relatively little effort. 
       FIGS. 7-9  pertain to chopping block  12 , a specialized embodiment that complements splitting tool  10 , to complete a wood chopping system for kindling.  FIG. 7  provides a top view of the solid wood rectangular chopping block  12 , preferably having approximate outer dimensions including a length  50  of 1.5 ft, a width  52  of 1.0 ft, and a thickness  54  of 6 inches. According to a preferred embodiment, V-shaped recessed platform  42  is cut from one end of chopping block  12  and positioned symmetrically with respect to the width  52  of chopping block  12 . V-shaped recessed platform  42  preferably has straight sides  56  measuring about 12 inches, and is cut to a depth of about 1.5 inches. Open end  48  preferably has a width  57  of about 8 inches, leaving 2 inches of the solid chopping block  12  raised about the recessed platform  42  on either side. Likewise, the projection  58  of each of sides  56  along the length  50  of the chopping block  12  is preferably also about 8 inches. Recessed platform  42  provides a secure base to hold a subject piece of wood steady for splitting by splitting tool  10 , and a means of resisting the additional leverage imparted to the wood through the use of tapered secondary cutting blade  32 . 
       FIGS. 10-14  show a second embodiment of a splitting tool. Referring primarily, but not exclusively, to  FIG. 10 , splitting tool  100  has a cutting head  102 , a handle  104  and a handle extension  106 . The cutting head has a first cutting edge  108 , and the handle  104  and handle extension  106  are substantially perpendicular to the first cutting edge. The bottom of the handle has a second cutting edge  110  that is also perpendicular to the first cutting edge  108 . 
     In addition to the first cutting edge, the cutting head comprises a top portion  112 , having a front face  114  and a back face  116  that are preferably essentially parallel to one another. “Essentially” is used herein to mean that, while not necessarily precisely parallel, the top portion would be understood to be of uniform thickness from front to back as a practical matter. However, it is to be understood that, while the use of a top portion having uniform thickness is desirable for cutting head strength, a non-uniform thickness may be used without departing from the principles of the invention. The cutting head also comprises a middle portion  118 , having a front surface  120  and a back surface  122  that taper from the front surface  114  and back surface  116  of the top portion toward the first cutting edge  108 . The cutting edge is formed to be sharp, as for example by grinding the bottom edge of the cutting head. 
     Referring to  FIGS. 11 and 12  in particular, the cutting head preferably has a flat portion  124  opposite the first cutting blade  108 . This facilitates the application of impulses of force to the cutting head when it is wedged into a piece of wood, for example by striking it with a piece of kindling. To this end, it is preferred that the flat portion  124  of the cutting head actually extends along the top  126  of the handle  104 . The cutting head further comprises a first side  128  and a second side  130 , which taper outwardly from the top of the cutting head to the first cutting edge  108  at the bottom of the cutting head. 
     Turning to  FIG. 10  and  FIG. 13  in particular, the second cutting blade, which is disposed on the bottom of the handle  104  starts at the bottom of the handle spaced at a location  132  away from the cutting head and extends arcuately toward the cutting head terminating at a location  134  lower than the bottom of the handle. The two side surfaces  135 ,  136  taper away from the second cutting edge and from one another to form arcuate surface transitions  137  in both sides of the handle. 
     It has been found that, while it is preferable for strength that the cutting head and handle be made of metal, such as steel, it is also preferable that the handle extension  106  be made of wood, or material having strength and resiliency characteristics similar to wood, such as suitable plastic, fiberglass or carbon fiber material, for example. The integral metal cutting head and handle also provide an advantage over other impact hand tools that employ a handle, typically made of wood, connected to a separate head having a hole, or eye, in which an end of the handle is inserted for attachment to the head. The advantage is that while an eye in the head will weaken the head&#39;s ability to withstand blows from the top, such as those that can be the result of using a hammer to drive the cutting blade further into wood, that is not the case with the integral head and cutting blade. 
     In this second embodiment, the handle includes recesses  140  on both sides thereof, as shown by  FIG. 14 , which produces an “I” shaped cross section at the rear portion of the handle. Preferably, the recesses terminate adjacent the beginning of the second cutting blade with semi-circular ends  142 . The handle extension is then attached by a slotted end  143  that fits into the recesses and is held in place by threaded fasteners  146  passing through apertures  150  and  152 , respectively, in the handle and handle extension. 
     Turning now to  FIG. 15 , a third embodiment of a splitting tool  200  comprises a handle shaft  214  and, attached perpendicularly to a distal end  216  of the handle shaft  214 , a tapered cutting head  218  similar to the cutting head shown in  FIGS. 10 and 11 . However in this case the handle shaft  214  terminates in a “U” shaped portion, viewed from the side as shown in  FIGS. 15, 16 and 17 , having a top tang  215  and a bottom tang  217 , the cross sections of each tang being generally “D” shaped with the convex portions  219  and  221  of the top and bottom tangs, respectively, both being inwardly directed toward a handle extension  206 , as shown in  FIG. 20 . The handle extension is preferably made of wood or a synthetic material. Referring to  FIG. 16 , for orientation purposes dimension  201  can be considered the dimension along which the head is adapted to transfer striking force and a second dimension  203 , which is non-parallel to the first dimension, can be considered the dimension along which the handle shaft extends away from the head. Typically dimension  203  would be substantially perpendicular to dimension  201 , though a significant deviation from perpendicular may not defeat the purposes of the subject matter disclosed herein. 
     In this case, the handle extension has a top groove  239  and a bottom groove  241  into which the top tang  215  and the bottom tang  217 , respectively, fit so as to form a joint between the handle shaft  214  of the cutting head and the handle extension, as particularly shown in  FIGS. 16, 17 and 20 . It may be noted from  FIG. 20  that the tangs  215  and  217  and the grooves  239  and  241  have mating surfaces configured so that one of the mating surfaces nests in the other. Accordingly, both the tangs and the grooves may be referred to generically as “nesting structures.” In addition, the tangs are outwardly disposed relative to the grooves, so the tangs may be referred to more specifically as “outer nesting structures” with the grooves being referred to more specifically as “inner nesting structures.” The top tang  215  includes at least one aperture for receiving at least one fastener, but preferably two apertures  242  and  244  are provided for passing respective fasteners  246  and  248  there through. Similarly, the grooved portion  250  of the handle extension  206  preferably includes respective apertures  252  and  254  for receiving fasteners  246  and  248 , and the bottom tang also preferably includes apertures  260  and  262  for receiving fasteners  246  and  248 , respectively, as particularly shown in  FIG. 16 . 
     Preferably the fasteners  246  and  248  are threaded fasteners that slip through apertures  242  and  244 , respectively, of the top tang  215 , and through apertures  252  and  254 , respectively, of the grooved portion  250  of the handle extension  206  and engage the apertures  260  and  262  of the bottom tang  217 , having complementary threads, to firmly attach the handle extension  216  to the handle shaft  214 . However, it is to be understood that other types of fasteners, including bolt and nut combinations as well as opposing wood screws could be used. 
     The tang, groove and fastener interlocking attachment mechanism described above with respect to  FIGS. 15 through 20  which feature the cutting head  218 , can also be used with other hand tool striking, or impact, tools. This is because, among other things, it resists torque in all directions, typically produced when exerting leverage with such a tool when it has penetrated an object, while only producing minimal shear force on the threaded fasteners. 
     For examples, such devices include, but are not limited to, a mattock  300 , comprising a mattock head  302  having a handle shaft  303  including top and bottom tangs  304  and  306 , respectively, and a grooved handle extension  308  held in place by fasteners  310  and  312 , as shown in  FIG. 21 ; a pick axe  400 , comprising a pick axe head  402  having a handle shaft  403  including top and bottom tangs  404  and  406 , respectively, and a grooved handle extension  408  held in together by fasteners  410  and  412 , as shown in  FIG. 22 ; and a hammer, for example, a claw hammer  500 , comprising a hammer head  502  having a handle extension  503  including top and bottom tangs  504  and  506 , respectively, and a grooved handle extension  508  held together by fasteners  510  and  512 , as shown in  FIG. 23 . The inclusion of these examples is not intended to be exhaustive or to limit the scope of the claims. 
     Turning to  FIGS. 24 and 25 , an embodiment of a novel woodsman&#39;s hatchet  600  is disclosed. The woodsman&#39;s hatchet comprises an hatchet head  602  having a handle shaft  603  including top and bottom tangs  604  and  606 , respectively, and a grooved handle extension  608  held place by fasteners  610  and  612 , as described above with respect to  FIGS. 15 through 20 . However, in this case the head  602  of the woodsman&#39;s hatchet  600  not only has a first cutting blade  614  disposed at one end of the head  602  and oriented substantially perpendicular to the longitudinal axis of the handle shaft  606 , and a second cutting blade  616  formed by the handle shaft, as described above with respect to the embodiment of  FIGS. 15 through 20 , but also has third cutting blade  618  disposed at the other end of the head  602 . The third cutting blade  618  is oriented substantially perpendicular to the first cutting blade  614  and substantially parallel to the longitudinal axis of the handle shaft. This enables a user to rotate the axe about the longitudinal axis of the handle shaft so as to facilitate cutting wood faster and also turning wood debris into chips. Preferably, the entire woodsman&#39;s hatchet head comprises a single, unitary, metal member. 
     Although certain embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a wide variety of alternative or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments illustrated and described without departing from the scope of the present invention. Those with skill in the art will readily appreciate that embodiments in accordance with the present invention may be implemented in a very wide variety of ways. This application is intended to cover any adaptations or variations of the embodiments discussed herein. 
     The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, to exclude equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only the claims that follow.