Abstract:
The disclosed and claimed concept provides for an overmold that is applied to substantially all of the exposed portions of a wood handle for a tool.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The disclosed concept relates to a wood tool handle having an overmold and, more specifically, to a wood handle wherein substantially all of the handle surface is protected by the overmold. 
         [0003]    2. Background Information 
         [0004]    Tools, and more specifically tool handles, are made from different materials having different advantages and disadvantages. For example, wood, and especially hickory wood, is known to be lightweight, impact absorbent, inexpensive, and strong. Hickory wood, however, is subject to degradation from exposure to the elements. Fiberglass handles, on the other hand, are less effected by exposure to the elements, but may be heavy and less impact resistant. Metal handles are strong and lightweight, but are expensive and do not absorb impact shocks. 
         [0005]    One method of improving handles is to apply a protective coating over the handle member. Wood handles often have a coating of varnish or a similar material that provides some protection form the elements. Metal and fiberglass handles may have a plastic coating or a preformed sheath disposed thereon. Such plastic is often an injection molded plastic. Injection molded plastics are strong and may help dampen the shock of impact. However, given that wood handles must retain some moisture so as to retain their resilience, and as applying injection molded plastic requires heating the plastic to the point where applying the molten plastic causes water within a wood handle to be converted to steam, there has not been a method to apply a plastic overmold to substantially all of a wood handle. 
         [0006]    As set forth in U.S. Pat. Nos. 4,287,640 and 4,344,901, it is known to apply an overmold to a portion of a wood handle. As noted in those patents, the portion of the handle to have an overmold applied thereto is subjected to additional drying. That is, the portion of the handle that is supported by the overmold is dried more than the unsupported portions of the handle. Thus, the unsupported portion of the handle retains its resilience while the protected portion is supported by the overmold. 
       SUMMARY OF THE INVENTION 
       [0007]    The disclosed and claimed concept provides for an overmold that is applied to substantially all of the exposed portions of a wood handle. That is, the handle is an elongated wood member having a first end, a medial portion, and a second end. The first end is sized and shaped to fit within the eye of a tool head. The second end has a bore hole. The medial portion and the second end, except for the bore hole, are enclosed in the injection molded overmold. Thus, when the handle member first end is enclosed by the tool head eye, the tool handle is substantially protected from the elements and other forms of wear and tear. That is, the handle member first end is protected by the tool head and the overmold is applied to substantially all of the handle member medial portion and second end. 
         [0008]    During manufacture a wood handle member, such as but not limited to a hickory handle member, is typically kiln dried until the moisture content is between about 12% and 18%. With this moisture content, the handle member retains a sufficient resilience for use as a handle member on an impact tool, such as, but not limited to, a sledge hammer. Per the disclosed method, the entire handle is further air dried until the moisture content is below 10%. The handle member is then placed in a mold. The mold is structured so that the handle member first end and at least the bore hole on the second end will not be exposed to the molten material being applied to the handle member. Thus, when the mold is filled with molten plastic, and more preferably molten polypropylene, the handle member first end and at least the bore hole on the second end are not enclosed and are free to vent steam. That is, application of the molten plastic causes water within the handle to be converted to steam; this steam must exit the handle without passing through the molten plastic. By having the first end and the bore hole exposed, the steam is free to pass through these locations and does not disturb the molten plastic. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which: 
           [0010]      FIG. 1  is an isometric view of a tool; 
           [0011]      FIG. 2  is a an isometric view of a tool handle assembly; 
           [0012]      FIG. 3  is a cross-sectional view of the tool handle assembly; 
           [0013]      FIG. 4  is an isometric view of a wooden handle in a mold; and 
           [0014]      FIG. 5  is a flow chart of the disclosed method. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0015]    As used herein, an “overmold” is a layer of material applied to a substrate by injection molding. 
         [0016]    As used herein, “generally uniform” and/or “generally smooth” when used in reference to the overmold outer surface means that the outer surface does not include any significant deformations in the overmold outer surface. Examples of insignificant deformations include, but are not limited to, a pattern of uniform ridges and valleys structured to act as a gripping surface, a decoration, logo, or trademark formed in a discrete location, or a window formed in a discrete location and structured to show the substrate. Such insignificant deformations are intentional and are typically incorporated into the mold. Alternatively, such intentional and/or insignificant deformations may be carved or cut into the overmold after application to the wood member. 
         [0017]    As used herein, “substantially smooth” when used in reference to the overmold outer surface means that the outer surface does not include any decorative deformations or breaks in the overmold outer surface. There may, however, be a limited number of small openings such as those structured to assist in the venting of steam from the handle during application of the overmold. A “limited number” is about 12 and “small openings” are between about 1/8  and 3/8  inch in diameter and more preferably about 1/4  inch in diameter. 
         [0018]    As used herein, “coupled” means a link between two or more elements, whether direct or indirect, so long as a link occurs. 
         [0019]    As used herein, “directly coupled” means that two elements are directly in contact with each other. 
         [0020]    As used herein, “fixedly coupled” or “fixed” means that two components are coupled so as to move as one while maintaining a constant orientation relative to each other. 
         [0021]    As shown in  FIG. 1 , a tool  10  includes a tool head assembly  12  and a tool handle assembly  20 . The tool  10  may be any type of tool  10 , such as, but not limited to, a sledge hammer  11  as shown. The tool head assembly  12  includes a tool head  14  and a coupling device  16 . The tool head  14  is typically made from metal and includes an opening, more commonly identified as the eye  18 . The eye  18  extends through the tool head  14  and is structured to have a portion of a tool handle assembly  20  disposed therein. The coupling device  16  is preferably a mechanical coupling device such as, but not limited to one or more wedges  19 . 
         [0022]    The tool handle assembly  20  includes a wood member  22  and an overmold  24 . The wood member  22 , which may be, but is not limited to, hickory wood, is elongated and includes a first end  26 , a medial portion  28  and a second end  30 . The handle member first end  26  is sized and shaped to correspond to the size and shape of the tool head eye  18 . That is, the handle member first end  26  is sized and shaped to fit snuggly within the tool head eye  18 . The handle member first end  26  may have a cross-sectional area that is smaller than the handle member medial portion  28  immediately adjacent the handle member first end  26 . Preferably, the transition between the handle member first end  26  and the handle member medial portion  28  is a flange  32  that extends generally perpendicular to the longitudinal axis of the wood member  22 . 
         [0023]    The handle member medial portion  28  includes the portion of the wood member  22  below (as shown in the figures) the flange  32  to the handle member second end  30 . The handle member second end  30  includes an end face  34 . The second end face  34  is preferably generally perpendicular to the longitudinal axis of the wood member  22 , however, it is also known for the second end face  34  to be cut at an angle relative to the longitudinal axis of the wood member  22 . As used herein, a “generally perpendicular” end face shall include an angled second end face  34 . A bore hole  36  in the second end face  34  extends generally parallel to the longitudinal axis of the wood member  22 . 
         [0024]    The wood member  22  preferably has a length between about 31.75 and 32.25 inches, and more preferably 32.0 inches. The wood member  22  preferably has a cross-sectional area between about 0.75 sq. in. and 0.85 sq. in., and more preferably 0.80 sq. in. The cross-sectional area, which is typically generally oval in shape, may vary over the length of the wood member  22 . Typically, the wood member  22  has a greater cross-sectional area at, or near, either/both the first end  26  and the second end  30 . The bore hole  36  has a depth between about 1⅜″ and 1⅝″, and more preferably 1½″. The bore hole  36  preferably has a cross-sectional area between about 0.1725 sq. in. and 0.2217 sq. in., and more preferably 0.196 sq. in. 
         [0025]    The overmold  24  is preferably made from polypropylene. The overmold  24  is applied as a molten material that is injected into a mold, as described below. The overmold  24  is applied to substantially all of the handle member medial portion  28  and the handle member second end  30 . The overmold  24  does not cover the handle member first end  26  or the bore hole  36  during application; as discussed below, a hollow tube  62  is inserted into the bore hole  26  to allow for venting steam. After application of the overmold  24  and removal of the hollow tube  62 , the overmold  24  material may swell into the bore hole  26 . It is noted that the overmold  24  may cover a portion, or all, of the second end face  34  other than the bore hole  26  as described above. The overmold  24  has a thickness, when dry, of between about 0.1 inch and 0.2 inch, and more preferably 0.125 inch. The thickness may vary over the length of the handle and/or on different sides of the handle. Further, it is more preferable that the overmold  24  has a thickness of no less than 0.1 inch. It is noted that the thickness of the overmold  24 , as well as the temperature of the overmold  24  in the molten state, effect the amount of heat transferred to the wood member  22  during application of the overmold  24 . That is, the thicker/hotter the molten material applied to the wood member  22 , the greater the amount of heat added to the wood member  22 . The more heat that is added to the wood member  22 , the more moisture in the wood member  22  is converted to steam. 
         [0026]    The overmold  24  has an outer surface  40  that may be either generally uniform, generally smooth, or substantially smooth. A generally uniform outer surface on an overmold  24  may include ridges/valleys  42  formed, or cut, into the overmold  24 . The valleys  42  do not extend to the surface of the wood member  22 . The ridges/valleys  42  are structured to improve the grip of a user. A generally smooth overmold outer surface  40  extends generally parallel to the outer surface of the underlying wood member  22  and is generally free from deformations. As defined above, a generally smooth overmold outer surface  40  may include an intentional “deformation”  41  in the overmold outer surface  40  at a discrete location, e.g. a logo or a window formed in the overmold  22 . A substantially smooth overmold outer surface  40  is substantially free of any decorative deformations in the overmold outer surface  40 . That is, the overmold outer surface  40  extends substantially parallel to the outer surface of the underlying wood member  22  and is substantially free from deformations. A substantially smooth overmold outer surface  40  may still have a limited number of openings  38  therethrough. As described below, the wood member  22  may be supported by a limited number of pins  50  and more preferably vent pins  52 , while in the injection mold cavity  60  ( FIG. 4 ). The vent pins  52  are hollow and are structured to allow steam to pass therethrough. The vent pins  52  contact the wood member  22  and, as such, during application of the overmold  24 , the overmold  24  material forms vent openings  56  about the locations of the vent pins  52 . As with the bore hole  36 , the overmold may expand into the vent openings  56  while cooling. 
         [0027]    When assembled, the tool  10  has the wood member first end  26  disposed in the tool head eye  18 . The coupling device  16 , which is preferably a wedge  19 , is inserted into the axial face of the wood member first end  26 . This causes the material that forms the wood member first end  26  to be deformed laterally thereby creating a mechanical lock between the tool head  14  and the wood member  22 . In this configuration, the overmold  24  covers the wood member medial portion  28  and second end  30 , and may cover substantially all of the second end face  34  except for the bore hole  36 . Further, the tool head  14  covers most of the wood member first end  26 . Thus, substantially all of the wood member  22  is enclosed and protected within the overmold  24  and tool head  14 . 
         [0028]    The method of creating the tool handle assembly  20  includes the following steps. Providing  100  an elongated wood member  22  shaped for use as a tool handle, the wood member  22  having a first end  26 , a medial portion  28  and a second end  30 ; placing  102  the wood member  22  into an injection mold cavity  60  (partially shown in  FIG. 4 , it is understood that the mold has an upper half, not shown, that is similar to the lower half; when the molds are joined a cavity is formed about the wood member  22 ); and injecting  104  a molten material into the mold cavity to apply the material to the wood member medial portion  28  and second end  30 . It is noted that the mold cavity  60  is slightly greater in cross-sectional area than the wood member  22 . That is, the mold cavity  60  allows for an overmold  24  having a dry/cool thickness of between about 0.1 inch and 0.2 inch, but preferably not less than 0.1 inch in thickness. The size of the mold  60  cavity may vary depending upon the properties of the material between the liquid/hot application and the cool/dry resulting overmold  24 , however, as discussed below, the molten material typically is between about 0.1 inch and 0.2 inch thick, and more preferably about 0.125 inch thick. The wood member  22  is, preferably, held by first end  26  during application of the overmold material. It is noted, the bore hole  36  may have a hollow tube  62  inserted therein for support. That is, the hollow tube  62  extends from the inner surface of the mold  60  and is structured to be snugly inserted into the bore hole  36 . The hollow tube  62  has a large enough cross-sectional area so that molten material cannot move past the hollow tube  62  and into the bore hole  36 . The hollow tube  62  is in fluid communication with at least one passage  64  through the mold  60 , whereby steam may be vented. Further, the wood member medial portion  28  may also be supported by a limited number of pins  50 . Preferably, the are about  6  pairs of pins  50  wherein the pins in the pair are disposed on opposite sides of the wood member&#39;s longitudinal axis. More preferably, the pins  50  are vent pins  52 . A vent pin  52  is a hollow pin that is biased firmly against the wooden handle member  22 . The mold  60  preferably includes passage(s)  64  therein with are in fluid communication with the vent pins  52 . In this configuration, steam may pass from the wooden handle member  22  through the vent pins  52  and be exhausted via the passage  64 . Thus the overmold  24  covers generally all of the wood member medial portion  28  and wherein the overmold outer surface  40  is generally smooth, generally uniform, or substantially smooth. 
         [0029]    Preferably, the wood member  22  does not have a high moisture content prior to applying the overmold  24  thereto. Thus, the step of providing  100  an elongated wood member  22  shaped for use as a tool handle preferably includes the step of providing  110  a wood member  22  with a moisture content of below about 10%. More preferably, the step of providing  110  a wood member with a moisture content of below about 10% includes the steps of kiln drying  112  the wood member  22  until the moisture content is between about 12% and 15%, and, air drying  114  the wood member  22  until the moisture content is below about 10% but above about 8%. Further, as detailed above, it is desirable for the wood member second end  30  to have a bore hole  36 . Thus, the step of providing  100  an elongated wood member  22  shaped for use as a tool handle preferably includes the step of providing  116  a wood member  22  with a bore hole  36  in the second end  30 . 
         [0030]    The step of injecting  104  a molten material into the mold cavity  60  to apply the material to the wood member medial portion  28  and second end  30  includes the steps of applying  120  the material in a molten state, allowing  122  the material to cool until the material is substantially rigid, and removing  124  the wood member from the mold  60 . When the molten material, which is preferably polypropylene at a temperature between about  425  and  450 , is injected  104  into the mold  60 , the molten material is applied to the wood member medial portion  28  and second end  30 . The heat imparted to the wood member  22  is sufficient to cause the residual moisture in the wood member  22  to be converted to steam. After application and cooling of the molten material, the wood member  22  has a moisture content of between about 8% and 10%, and more preferably about 10%. As noted above, the step of applying  120  the material in a molten state includes the step of applying  121  a layer of molten material that is between about 0.1 inch and 0.2 inch thick, and more preferably about 0.125 inch thick. 
         [0031]    As noted above, the steam is vented from the wood member  22  and generally seeks the path of least resistance. That is, as the wood member medial portion  28  and second end  30 , except for the bore hole  36 , are covered in the molten material, the path of least resistance is through the wood member first end  26  and the bore hole  36 . Further, to ensure that the wood member  22  is not completely encased by the molten material, the step of applying  120  the material in a molten state includes the step of preventing  128  the molten material from contacting the wooden member first end  26 . 
         [0032]    The handle assembly  20  may be coupled to a tool head  14  in order to form a tool  10 . That is, the method may include the further steps of providing  130  a coupling device  16 , providing  132  a tool head  14  having an eye  18 , said eye shaped to correspond to the wooden member first end  26 , inserting  134  the wood member first end  26  into the tool head eye  18 , and, fixing  136  the wood member first end to the tool head with the coupling device  16 . As noted above, it is preferable to have a mechanical coupling, thus the step of providing  130  a coupling device may include the steps of providing  140  a wedge  19 , and inserting  142  said wedge into the wood member first end  26 . 
         [0033]    While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.