Patent Abstract:
A hand held hammer includes a handle incorporating a series of outwardly extending pegs providing gripping power between the user&#39;s hands and the handle. In some embodiments, the pegs are spaced far enough part to make it overly painful to swing the hammer bare handed. In some embodiments, the cumulative surface area of the pegs occupy less than 8% of the surface area of the handle. The pegs may be embedded in a plastic handle, captivated to the exterior of a conventional handle or may comprise an integral part of a plastic handle.

Full Description:
This application is based on U.S. Provisional Patent Application Ser. No. 62/071,868 filed Oct. 6, 2014, priority of which is claimed and which is incorporated herein by reference. 
    
    
     This invention relates to hand held tools and more particularly to tool handles for hand held tools which have high gripping power. 
     BACKGROUND OF THE INVENTION 
     There are many industries and situations where hand held impact tools are swung with considerable force. One handed hammers, two handed sledge hammers and axes are common examples. In some situations, circumstances are such that the user cannot grip the tool handle securely. A common example is where the user&#39;s hands or the tool handle is wet. Oil, grease, drilling mud and other similar slick materials make it difficult to grasp a tool handle and swing the tool with the requisite force without losing grip of the handle. There are obvious safety concerns to the user, to bystanders and to nearby equipment. 
     There have been some attempts made in manufactured tool handles to make them rougher, as with grooves, ribs of hard or soft rubber and the like. There have been improvised attempts as with string, tape or the like wound around the handle. 
     Disclosures of interest are found in U.S. Pat. Nos. 3,585,101; 4,825,552; 5,097,566; 5,234,740; 6,372,323; 6,610,382; 7,309,519; 7,703,179 and 8,277,922 along with U.S. Printed Patent Application; 2012/0027990 and Japan Patent 2012158091. 
     SUMMARY OF THE INVENTION 
     A tool handle includes a series of outwardly extending pegs which are sufficiently far apart to allow the user&#39;s hand to abut the tool handle. The pegs are rigid, meaning they indent the skin of the user when the tool handle is forcibly grasped. In some embodiments, the pegs are long enough and spaced far enough apart to make it overly painful to grasp and forcibly swing the tool bare handed. In some embodiments the pegs are embedded in a molded handle or formed during molding of a handle. In other embodiments, the pegs are captivated against an exterior of the handle, as by the use of shrink wrap bands. 
     It is an object of this invention to provide an improved tool and tool handle. 
     Another object of this invention is to provide an improved tool handle for impact tools which provides high gripping power. 
     These and other objects and advantages of this invention will become more fully apparent as this description proceeds. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a hand held tool incorporating a handle of this invention; 
         FIG. 2  is an end view of the tool handle of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of  FIG. 1 , taken substantially along line  3 - 3  thereof as viewed in the direction, indicated by the arrows; 
         FIG. 4  is a partial side view of another embodiment of a tool handle of this invention; 
         FIG. 5  is a cross-sectional view of  FIG. 4 , taken substantially along line  5 - 5  thereof as viewed in the direction indicated by the arrows; 
         FIG. 6  is a cross-sectional view, similar to  FIG. 5 , of another embodiment of a tool handle. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1-3 , there is illustrated an impact tool  10  such as a one handed hammer having a handle  12  and an impact head  14 . The impact tool  10  may be of any suitable type such as the hammer/chisel form shown, a sledge hammer, axe, maul or the like. 
     The handle  10  includes a conventional shaft  16  which is typically of wood but which may be of any suitable material, such as plastic, metal, fiberglass or the like. A series of rigid pegs  18  are captivated to the shaft  16  in any suitable manner, as by the use of sections of shrink wrap tubing  20 . The pegs  18  include an enlarged head  22  which may be buttressed by a beveled or unbeveled washer  24  and a shaft  26  which protrudes through an opening in the tubing  20 . The peg shaft  26  may terminate in a flat blunt end  28  perpendicular to an axis  30  of the shaft  26  and may preferably include a tapered, beveled or chamfered edge  32  to avoid a sharp edge on the end  28  of the peg  18 . 
     The pegs  18  may extend outwardly from the handle  12  in a more-or-less radial fashion as shown in  FIG. 2 . The pegs  18  may be symmetrically placed about the handle  12  as in  FIG. 2  where the pegs  18  are spaced 45° apart or may be more randomly positioned. Similarly, each group of pegs  18 , i.e. those bound to the shaft  16  by a single length of tubing  20 , may be identically positioned to the group above or below it or may be staggered in some fashion. The number of pegs  18  bound by each of the tubing sections  20  may vary considerably but there may be 4-20 pegs  18  bound by each of the tubing sections  20  and may preferably be 6-8 pegs  18  for each tubing section  20 . There may be a series of tubing sections  20  or a single long length of tubing  20  in which the pegs  18  are held. 
     To apply the pegs  18  to the handle shaft  16 , the washers  24  are installed on the pegs  18 , the pegs  18  are passed through openings in the tubing  20  which are then slipped over the end of the handle shaft  16  to a desired location. A heat gun (not shown) such as a hair dryer is used to shrink the tubing  20  onto the shaft  16  and thereby captivate the pegs  18  to an exterior of the handle  12 . Some shrink wrap material includes glue on the underside and some may not. In any event, glue may be added to the underside of the tubing  20  to promote adhesion to the handle  12 . 
     The function of the pegs  18  is to increase the frictional forces between the user&#39;s hand and the handle  12 . By making the pegs  18  small in area, spaced widely apart and relatively long, the forces in some embodiments are so great that a user cannot hold the hammer  10  bare handed and swing in a normal forceful manner because the pain is too great. This may sound disadvantageous but, in some industries like the upstream oil and gas industry, it is counter-intuitively desirable because workers are encouraged or required to wear gloves. By making the pegs  18  so the handle  12  is painful to grasp, one accomplishes two ends, i.e. create maximum frictional force between the user&#39;s hand and the handle  12  and encourage the worker to wear gloves. 
     In one sense, the measurement of pain is a subjective matter but, in another sense, is subject to objective consideration. As used herein, the pain being so great that the person cannot hold onto the handle and swing it forcibly means that at least ninety percent of a random selection of adult American males cannot drive a common six penny nail completely into the short side of a 2×4 commercial grade piece of lumber in thirty seconds while gripping the handle bare handed in the gripping area between the upper and lower peg boundaries. 
     To promote the frictional forces between the handle  12  and the user&#39;s hand, it is desirable to make the pegs  18  of small cross-sectional size, widely dispersed and sufficiently long. The cross-sectional area of each peg shaft  26 , taken perpendicular to the axis  30  along a section of maximum diameter or value, is relatively small and may be in the range of 0.002-0.07 square inches each and may preferably be in the range of 0.008-0.02 square inches each. It may be preferred that each of the pegs  26  be identical for ease of manufacture but the pegs  18  may be of mixed cross-sectional size if desired. 
     The peg shaft  26  may be of complex shape but may preferably or conveniently be slightly tapered or cylindrical. The diameter of cylindrical peg shafts  26  may vary considerably but typically may be in the range of 0.05-0.3 inches and may preferably be in the range of 0.08-0.20 inches. 
     The cumulative cross-sectional area of the pegs  18  is very small compared to the surface area of either the shrink wrap tubing  20  or to the handle shaft  16 . The more appropriate comparison in the embodiment of  FIGS. 1-3  is to the diameter of the tubing sections  20  which abuts the user&#39;s hand or glove in use. The cumulative cross-sectional area of the pegs  18 , from an upper peg boundary  34  to a lower peg boundary  36  which constitute the gripping area of the handle  16 , may be in the range of about ½-8% of the area between the boundaries  34 ,  36 . The cumulative cross-sectional area of the pegs  18 , between the boundaries  28 ,  30 , may preferably be in the range of 1-2.5%. The exact number of pegs in any particular embodiment depends, of course, on the cross-sectional area of each peg. 
     The pegs  18  do not have to be symmetrically or evenly dispersed on the handle shaft  16  as shown in the drawings but there is no adult male hand sized area on the handle shaft  16 , i.e. a distance of 3″ or greater along the axis of the shaft  16 , between the boundaries  34 ,  36  that is free of pegs  18 . In some embodiments, there may preferably be at least one peg  18  in any square having an area of two square inches between the boundaries  34 ,  36 . 
     One factor determining the rigidity of the pegs  18  is the material from which they are made. The pegs  18  may be of any suitable metal, plastic or composite of considerable hardness. The pegs may be soft metals such as copper or aluminum having a 2.5 or greater hardness on the Mohs scale. Copper alloys, aluminum alloys, iron and iron alloys are, of course, considerably harder and may be used. Hard polymers such as polycarbonates, polypropylene, polyamides and similar plastics having a Shore Durometer in excess of 70 may also be used. Plastics presumptively have a disadvantage because, when broken, they produce sharp edges. Sharp edges in fact promote frictional forces between the user&#39;s glove and the handle  16  but they wear gloves at an inordinately high rate. 
     Another factor determining the rigidity of the pegs  18  is the length of the pegs  18  above the surface of the sections  20  relative to their diameter. When the pegs  18  are made of suitable metals or plastics and are no longer than 0.4″ long, they remain rigid and are not flexible because of overly large aspect ratios. 
     The exposed length of the pegs  18  above the shrink wrap tubing sections  20  has another effect. If the pegs  18  are too short, they do not produce sufficient frictional forces. If the pegs  18  are too long, they become like spikes and are too sharp. The pegs  18  may be exposed above the shrink wrap section  20  in the range of 0.05-0.4″ and may preferably extend in the range of 0.1-0.2″ above the exterior of the shrink wrap tubing sections  20 . Although the pegs  18  shown in  FIGS. 1 and 2  are of the same length above the exterior of the tubing  20 , they may be of random length and may extend at different lengths above the tubing  20 . 
     Referring to  FIGS. 4-5 , there is illustrated another tool handle  40  which may be molded from a suitable polymer, fiberglass, composite material or the like. The handle  40  accordingly includes a shaft  42  in which are embedded a series of rigid pegs  44 . The pegs  44  may include an enlarged lower end or flange  46  promoting retention of the peg  44 . The size, spacing and distribution of the pegs  44  relative to the handle shaft  42  may be the same as the size, spacing and distribution of the pegs  18  relative to the shrink wrap sections  20 . 
     Referring to  FIG. 6 , there is illustrated another molded tool handle  50  having a handle shaft  52  from which extend a series of rigid pegs  54  which are integral with the handle shaft  52  and are molded from the same material as the handle shaft  52  during manufacture. The size, spacing and distribution of the pegs  54  relative to the handle shaft  52  may be the same as the size, spacing and distribution of the pegs  18  relative to the shrink wrap sections  20 . 
     The type of work gloves which may be used with the handle  16  of this invention may vary widely. Plastic dot gloves, leather, suede and more modern work gloves, such as those made by Wells Lamont of Niles, Ill. which is a division of The Marmon Group of Chicago, Ill. or Ringers Gloves of Houston, Tex. and similar gloves may be suitable for use to swing the hammer  10  without the least discomfort. The basic reason that one can grasp the handle  16  without discomfort is that work gloves spread the effect of the blunt peg ends  28  over a greater area of the user&#39;s hand. 
     Although this invention has been disclosed and described in its preferred forms with a certain degree of particularity, it is understood that the present disclosure of the preferred forms is only by way of example and that numerous changes in the details of operation and in the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

Technology Classification (CPC): 1