Patent Abstract:
A foot rest for a post-hole digger and post-hole diggers using the foot rest are disclosed. The foot rest includes two portions, one attached to each shaft of the post-hole digger. The two portions have structure that allows them to engage one another when the two shafts of the post-hole digger are vertical. The foot rest does not extend beyond the bore diameter of the post-hole digger. Thus, in order to keep the user&#39;s feet on the relatively short foot rest, the contact surface of the foot rest may be angled. In some embodiments, the foot rest may be symmetrical, so that either side may be used as the upper surface. A post-hole digger including the foot rests typically includes at least two foot rests, spaced from one another and facing different directions along the shafts of the tool.

Full Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    In general, the invention relates to digging tools, and more particularly, to post-hole digging tools with footrests. 
         [0003]    2. Description of Related Art 
         [0004]    A post-hole digger is a digging tool intended to dig deep, narrow holes for the placement of fence posts, sign posts, and other, similar structures. In a typical post-hole digger, the head of the tool includes two rounded digging blades that face one another and are connected to one another by a hinge. Each shovel head is connected to its own shaft. To use the device, the user drives the tool into the ground and then moves the handles to clamp down on some of the soil that the tool has sunk into before extracting the head, along with the soil, from the hole. The process is repeated until the hole is of sufficient size and depth. 
         [0005]    With a typical post-hole digger, the user uses his or her arms to drive the tool into the ground. However, the typical tool does not allow the user to use his or her legs effectively in the process of driving the tool into the ground, and most people have more strength in their legs than in their arms. Thus, using a conventional post-hole digger can be tiring and inefficient. 
         [0006]    Over the years, there have been isolated attempts to create post-hole diggers that allow a user to use his or her feet to drive the tool head into the ground, or to use other parts of the body for leverage. U.S. Pat. No. 5,669,648 to Luck is one example—the patent discloses post-hole diggers with a number of horizontal posts that are connected to the shafts with hinges, so that they can be swung up and out of the way if necessary. The horizontal posts can be used as foot rests for driving the tool head. However, the posts extend horizontally far beyond the tool itself, which may interfere with the soil when one tries to dig particularly deep holes. Moreover, the relatively long foot rests may increase the bending and tipping moments generated when pressure is applied, thus making the tool more difficult to use. Additionally, when the Luck tool is in use, dirt and soils may become lodged in the hinges of its foot rests, potentially causing the hinges to jam. If the foot rests open or the hinges jam open while the tool is in use, this could cause the foot rests to act like barbs on a hook, jamming the tool irretrievably in the hole. In fact, merely pulling the tool out of a hole may be enough to trigger the deployment of the foot rests. 
         [0007]    The Luck patent recognizes an additional issue with post-hole diggers: when driving the tool into the ground, it is helpful if the two shafts can function as one rigid piece. Luck addresses this issue with a separate, detachable top plate assembly including a reinforcement bar that is attached between the shafts close to the top of the tool. While this may serve to rigidify the tool when it is driven, the top plate assembly and reinforcement bar prevent the tool from closing to remove soil when it is in place, and it may be inconvenient for a user to repeatedly attach and remove the top plate assembly while the tool is in use. Beyond that inconvenience, it is very easy for the user to lose a detachable piece of a tool like the top plate assembly, which would render its advantages moot. 
       SUMMARY OF THE INVENTION 
       [0008]    One aspect of the invention relates to a foot rest for a post-hole digger. The foot rest includes two portions, one attached to each shaft of the post-hole digger. The two portions have structure that allows them to engage one another when the two shafts of the post-hole digger are vertical. The foot rest does not extend beyond the bore diameter of the post-hole digger. Thus, in order to keep the user&#39;s feet on the relatively short foot rest, the contact surface of the foot rest may be angled. In some embodiments, the foot rest may be symmetrical about a bisecting horizontal plane, so that either side may be used as the upper surface. 
         [0009]    Another aspect of the invention relates to a post-hole digger with foot rests. The post-hole digger has two rounded digging heads opposing one another and connected together at a hinge, with a shaft connected to each of the shovel heads. The post-hole digger includes at least one, and typically at least two, foot rests. The two foot rests face opposite directions and are spaced from one another along the shafts. 
         [0010]    Other aspects, features, and advantages of the invention will be set forth in the description that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0011]    The invention will be described with respect to the following drawing figures, in which like numerals represent like features throughout the figures, and in which: 
           [0012]      FIG. 1  is a perspective view of a post-hole digging tool according to one embodiment of the invention, shown in use; 
           [0013]      FIG. 2  is a top plan view of the tool of  FIG. 1 ; 
           [0014]      FIG. 3  is a partial side elevational view of the tool of  FIG. 1 , illustrating the shape of one of the foot rests; 
           [0015]      FIG. 4  is a side elevational view of the tool of  FIG. 1 ; 
           [0016]      FIG. 5  is a side elevational view of the tool of  FIG. 1  shown with handles apart; and 
           [0017]      FIG. 6  is a detail perspective view of a portion of the handle of the tool of  FIG. 1 , illustrating the engagement of the foot rests. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]      FIG. 1  is a perspective view of a post-hole digging tool, generally indicated at  10 , according to one embodiment of the invention. The tool  10  is shown in  FIG. 1  in use, digging a hole  12  in soil  14 . The tool head  16  comprises two downwardly-extending, rounded digging blades  18 ,  20  that face one another and are connected together at a hinge  22 , which pivots to allow the two digging blades  18 ,  20  to move closer together and farther apart. Each of the digging blades  18 ,  20  is connected to an individual shaft  24 ,  26  that, in the view of  FIG. 1 , extends vertically. 
         [0019]    The tool  10  has a pair of foot rests  28 ,  30  spaced from one another along the length of the shafts  24 ,  26 . Each foot rest  28 ,  30  extends in a different direction. The tool  10  may include any number of foot rests  28 ,  30  spaced from one another along the length of the shafts  24 ,  26 . In fact, if a particularly deep hole  12  is to be dug, it may be helpful to have three or four foot rests  28 ,  30  present. The presence of multiple foot rests  28 ,  30  may allow increased efficiency, in that the user can create an effective power stroke to drive the tool  10  regardless of its depth. With each foot rest  28 ,  30  extending in a different direction, the tool  10  provides knee clearance and makes it more difficult for a user who places his or her foot on a lower foot rest  30  to bump against an upper foot rest  28  with his or her knee. As will be described below in more detail, the foot rests  28 ,  30  may be provided separately and attached to the shafts  24 ,  26  as necessary. 
         [0020]    The illustration of  FIG. 1  shows the tool  10  in use, with the user&#39;s left foot on an upper foot rest  28  and a lower foot rest  30  closer to the ground level. While the tool  10  may be used in many different ways, the most effective power stroke will be achieved in most cases from a position similar to that shown in  FIG. 1 : one foot on the ground and the other on one of the foot rests  28 ,  30 . 
         [0021]      FIG. 2  is a top plan view of the tool  10  that illustrates one particular advantage of the tool  10 : the foot rests  28 ,  30  extend within the bore diameter  31  of the tool  10  (i.e., within the diameter of the tool head  16 ). This means that foot rests  28 ,  30  will not interfere with the soil  14  or prevent the digging of deep holes  12 , and it also places the center of foot pressure closer to the centerline of the tool  10 , which means that less bending moment will be generated as the tool  10  is driven into the soil  14 , and the tool  10  will be less likely to tip over in use. As shown in  FIG. 2 , the outer circumferential edge of each foot rest  28 ,  30  is slightly curved in the illustrated embodiment, although that need not be the case in all embodiments, so long as the foot rests  28 ,  30  extend only within the bore diameter  31  of the tool  10 . 
         [0022]    For most standard-sized post-hole diggers, each foot rest  28 ,  30  would be about 2.5 to 3.25 inches long, measured from the circumferential surfaces of the shafts  24 ,  26  outward. Multiple foot rests  28 ,  30  on the same tool  10  would typically be of the same size, although they may vary in size in some embodiments. 
         [0023]    Because the foot rests  28 ,  30  are relatively short in order to stay within the profile of the tool head  16 , the user&#39;s feet might have more of a tendency to slip off the foot rests  28 ,  30  as compared with a longer foot rest. To ameliorate this potential issue and assist in retaining the feet on the foot rests  28 ,  30 , the foot-contacting surface  33  of each foot rest  28 ,  30  is angled slightly upwardly, for example, approximately 10° degrees, as shown in the partial side elevational view of  FIG. 3 . This tends to force the foot toward the shaft  26  as pressure is applied. In other embodiments, up-angles in the range of about 5° to about 30° are suitable, with about 10° to about 20° being a particularly useful range. 
         [0024]    Additionally, the foot rest  28  includes a surface with gripping texture  32  to increase the friction on the sole of the user&#39;s shoe or to physically interlock with the tread of a user&#39;s shoe. As shown in  FIG. 4 , the foot rest  28  is symmetrical about a bisecting horizontal plane, with the foot rest  28  flaring out trapezoidally (as viewed in the side elevational view of  FIG. 3 ) to create the same angle on its upper and lower surfaces. The foot rest  28  also includes gripping texture  32  on its upper and lower surfaces. These symmetrical features allow the user to install the foot rest  28  on the shaft  26  with either side facing up. 
         [0025]    Additionally, as can be appreciated from  FIG. 2 , the two foot rests  28 ,  30  do not extend outwardly along the same line as the digging blades  18 ,  20 . Instead, they are offset (i.e., rotated) 90°. (Compare  FIG. 2  with FIG. 2 of U.S. Pat. No. 5,669,648, which was incorporated by reference above.) This arrangement of the foot rests  28 ,  30  relative to the digging blades  18 ,  20  potentially provides the user more space. 
         [0026]      FIG. 4  is a side elevational view of the tool  10  in the position of  FIGS. 1 and 2 . Because the foot rests  28 ,  30  are provided on two individual shafts  24 ,  26  and those shafts  24 ,  26  pivot with the hinge  22  of the tool head  16 , the foot rests  28 ,  30  are each comprised of two individual portions. For example, in the view of  FIG. 4 , the foot rest  28  includes portions  34  and  36 , and the foot rest  30  includes portions  38  and  40 . When the shafts  24 ,  26  are moved apart to capture the soil  14  and remove it from the hole  12 , the portions  34 ,  36  and  38 ,  40  are able to separate from one another, as shown in the side elevational view of  FIG. 5 . 
         [0027]    As shown in  FIG. 5  and the enlarged perspective view of  FIG. 6 , each of the portions  34 ,  36  has a collar  42  to secure it around one of the shafts  24 ,  26 . The collar  42  may be secured either by set screws  44  that bear directly against the shaft  24 ,  26 , or by a mechanism that tightens the collar  42  circumferentially to apply force. In some embodiments, the collars  42  may be permanently secured to the shafts  24 ,  26  by fasteners like screws, bolts, or dowel pins that actually embed in or transit through the shafts  24 ,  26 , but it may be more advantageous in most embodiments if the collars  42  are adjustable in position. In addition to these means of fastening the foot rests  28 ,  30  to the shafts  24 ,  26 , the foot rests  28 ,  30  may be overmolded onto the shafts  24 ,  26 , welded onto the shafts  24 ,  26 , or cast in place on the shafts  24 ,  26 . 
         [0028]    The two portions  34 ,  36 ,  38 ,  40  of each foot rest  28 ,  30  interlock and engage one another when the tool  10  is in the position shown in  FIGS. 1, 2, and 4 . As shown in  FIG. 6 , each portion  34 ,  36  has a peg  46 ,  48  that extends toward the other portion  34 ,  36 . Each portion  34 ,  36  also has a complementary receiving opening  50  (only one of the openings is shown in the view of  FIG. 6 ) positioned to accept the peg  46 ,  48  from the other portion  34 ,  36 . As can be appreciated from  FIG. 6 , aside from the pegs  46 ,  48 , the facing surfaces of the portions  34 ,  36  are essentially flat and are intended to be parallel to one another when the two shafts  24 ,  26  are parallel to one another. 
         [0029]    The engagement of the portions  34 ,  36 ,  38 ,  40  rigidifies the foot rests  28 ,  30 , making the result stronger and stiffer than two independent shafts  24 ,  26  would be. The engagement of the portions  34 ,  36 ,  38 ,  40  also maintains the alignment of the digging blades  18 ,  20  during digging, and may also be helpful when the user pushes or wiggles the shafts  24 ,  26  from side to side in the process of digging. As those of skill in the art will understand, driving force can be applied equally through both shafts  24 ,  26 . 
         [0030]    The manner of engagement of the portions  34 ,  36 ,  38 ,  40  may differ from embodiment to embodiment, and other embodiments may use other forms of connectors. One advantage of the pegs  46 ,  48  is that they do not require the user to manually disengage a latch before the shafts  24 ,  26  will part. However, in some embodiments, latches and other mechanisms that require the user to disengage them may be used. Additionally, because the pegs  46 ,  48  are permanently attached, they cannot be detached or lost. 
         [0031]    The foot rests  28 ,  30  may be made of any number of materials. For example, they may be made of a cast metal, such as aluminum or steel. They may also be molded from any number of plastics. For example, the foot rests  28 ,  30  may be made of nylon, polycarbonate/ABS blends, polyethylene-polypropylene blends or copolymers, or polyphthalamide. The foot rests  28 ,  30  may also be made of composite materials, including glass-filled plastics. In some cases, a layer of rubber, or another high-friction surface, may be applied to or co-molded with the upper and lower surfaces of the foot rests  28 ,  30 . 
         [0032]    As was described briefly above, tools  10  according to embodiments of the invention may be produced and sold in the form illustrated in  FIGS. 1-6 , with foot rests  28 ,  30  already installed at appropriate locations. Alternatively, kits including a number of foot rests  28 ,  30  may be sold for later attachment to a standard post-hole digging tool. In addition, kits may be sold for attaching additional foot rests  28 ,  30  to a tool that already includes them. 
         [0033]    While the invention has been described with respect to certain embodiments, the embodiments are intended to be exemplary, rather than limiting. Modifications and changes may be made within the scope of the invention, which is defined by the appended claims.

Technology Classification (CPC): 4