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BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to a ground-hole forming device and, more particularly, to a ground-hole forming device that muffles sound. 
         [0002]    In gas detecting operations, it is often necessary to dig holes at various places in the ground near where a leak is suspected to have occurred. Once the hole is formed and dug out, a gas detecting monitor is placed nearby and identifies whether a leak is present or not by determining levels of gases in the surrounding atmosphere. Generally, the hole is formed by an initial boring of a hole through asphalt and/or concrete and then forcing a long rod into the ground at the hole. The latter step is done by placing an end of the rod into the hole and hitting the other end with a hammering device. 
         [0003]    The impacts between the hammering device and the end of the rod generate a substantial amount of noise. Indeed, in some cases, the sounds generated by the impacts can be above a desired threshold. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0004]    According to one aspect of the invention, a ground-hole forming apparatus is provided and includes a drivable element, a bulb coupled to an end of the drivable element, the bulb including first and second resilient portions and a driving element including first and second ends, the driving element being movable by an operator in first and second directions such that the first and second ends drive ably impact the first and second resilient portions of the bulb, respectively, to thereby drive the drivable element in the first and second directions, respectively. The first and second resilient portions are configured to absorb and deaden respective impacts thereof with the first and second ends. 
         [0005]    According to another aspect of the invention, a ground-hole forming apparatus is provided and includes a first elongate member including a tube defining an interior having first and second ends, a first stopper at the first end and a second stopper at the second end, a second elongate member having third and fourth ends, the second elongate member being movable in first and second directions relative to the first elongate member and a bulb coupled to the third end and configured to constrain the third end in the interior. The bulb includes first and second resilient portions configured to impact the first and second stoppers, respectively, to terminate movement of the second elongate member relative to the first elongate member in the first and second directions, respectively. 
         [0006]    According to yet another aspect of the invention, a ground-hole forming apparatus is provided and includes a drivable element, a bulb coupled to an end of the drivable element and including first and second resilient portions, a driving element including first and second ends and being movable by an operator in first and second directions such that the first and second ends drive ably impact the first and second resilient portions of the bulb, respectively, to thereby drive the drivable element in the first and second directions, respectively. The first and second resilient portions are configured to absorb and deaden respective impacts thereof with the first and second ends. 
         [0007]    These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0009]      FIG. 1  is a side sectional view of a ground-hole forming apparatus in accordance with embodiments; 
           [0010]      FIG. 2  is an enlarged view of a portion of the ground-hole forming apparatus of  FIG. 1 ; 
           [0011]      FIG. 3  is an illustration of a bore-hole; 
           [0012]      FIGS. 4A and 4B  are illustrations of a process of forming a ground-hole at the bore-hole of  FIG. 3  using the ground-hole forming device of  FIGS. 1 and 2 ; and 
           [0013]      FIGS. 5A and 5B  are illustrations of a process of removing the ground-hole forming device from the ground-hole of  FIGS. 4A and 4B  so that the process of  FIGS. 4A and 4B  can be repeated. 
       
    
    
       [0014]    The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    As will be described below with reference to  FIGS. 1-3 , a ground-hole forming apparatus  10  is provided and may be used in the formation of ground-holes in the ground at bore-holes that are already formed in asphalt and/or concrete. The ground-hole forming apparatus  10  is provided with resilient portions that absorb and deaden sounds generated by impacts between various components of the ground-hole forming apparatus  10  so that the generated sounds may be limited to less than about  73  dBA. 
         [0016]    With reference to  FIGS. 1 and 2 , the ground-hole forming apparatus  10  is provided and includes a first elongate member  20 , a second elongate member  30  and a bulb  40 . The first elongate member  20  includes a tubular element  21  that has a compliant outer surface, which is appropriate for being gripped and manipulated by an operator. The tubular element  21  is formed to define an interior  22 . The interior  22  has a first end  221  and second end  222 , which is opposite the first end  221 . The first elongate member  20  further includes a first stopper  23 , which is disposed at or within the first end  221 , and a second stopper  24 , which is disposed at or within the second end  222 . 
         [0017]    The first stopper  23  may be provided as a full or substantially full closure of the tubular element  21  at the first end  221 . By contrast, the second stopper  24  is provided as a partial closure of the tubular element  21  that may be screw-coupled or otherwise fastened to the second end  222  of the tubular element. In the former case, the second stopper  24  may be provided with exterior threading  25  that is configured to register with interior threading  26  disposed on the tubular element  21  at the second end  222 . With the second stopper  24  provided as a partial closure of the tubular element  21 , the partial closure is formed to define an opening  240 . The second stopper  24  may include a gasket  241  disposed at the interior facing walls of the second stopper  24  to define the opening  240 . 
         [0018]    The second elongate member  30  is provided as a rod  31  formed of rigid material that has a third end  310 , a fourth end  311 , which is opposite the third end  310 , a central portion  312 , which is interposed between the third end  310  and the fourth end  311  and which may be formed with a similar shape as the opening  240 . More specifically, where the opening  240  is substantially circular, the central portion  312  may be substantially cylindrical. 
         [0019]    The second elongate member  30  is movable in first and second directions relative to the first elongate member  20 . The opening  240  defined by the second stopper  24  has a diameter, D 1 , which may be very slightly larger than a diameter, D 2 , of the central portion  312 . The second elongate member  30  is disposed to move in the first and second directions relative to the first elongate member  20  such that the central portion  312  slides through the opening  240  and, more specifically, the opening  240  defined by the gasket  241 . That is, the gasket  241  is configured to guide a sliding movement of the central portion  312  of the second elongate member  30  through the opening  240 . 
         [0020]    The bulb  40  is coupled to the third end  310  of the rod  31 . The bulb  40  is disposable in the interior  22  and is thus configured to cooperate with the first stopper  23  and the second stopper  24  to constrain the third end  310  of the rod  31  in the interior  22  as well. The bulb  40  includes a rigid element  41 , which may be formed of a metallic material and which may be affixed to the second elongate member  30  at the third end  310 . The bulb  40  further includes a first resilient portion  42 , which is formed of a resin-based material and is coupled to a leading side of the rigid element  41  defined in accordance with the movement of the second elongate member  30  relative to the first elongate member  20  in the first direction M 1 , and a second resilient portion  43 . The second resilient portion  43  may be formed of a resin-based material and may be coupled to a trailing side of the rigid element  41  defined in accordance with the movement of the second elongate member  30  relative to the first elongate member  20  in the first direction. 
         [0021]    It is to be understood that the leading and trailing sides of the rigid element  41  switch with respect to the direction of movement of the second elongate element  30  relative to the first elongate element  20 . However, for purposes of clarity and brevity, they will be defined herein with respect to only the first direction of movement M 1 . 
         [0022]    With the first stopper  23  provided as a full or substantially full closure of the tubular element  21 , the second resilient portion  43  cannot pass through the first end  221  during movement of the second elongate member  30  relative to the first elongate member  20  in the second direction M 2 . That is, the second resilient portion  43  is configured to impact the first stopper  23  and to terminate movement of the second elongate member  30  relative to the first elongate member  20  in the second direction M 2  as a result of the impact. Similarly, the first resilient portion  42  has a diameter D 3 , which is larger than the diameter D 1  of the opening  240 . Thus, with the second stopper  24  being provided as a partial closure that permits the movement of the second elongate member  30  relative to the first elongate member  20  in the first direction M 1 , the first resilient portion  42  cannot pass through the second end  222  during movement of the second elongate member  30  relative to the first elongate member  20  in the first direction M 1 . That is, the first resilient portion  42  is configured to impact the second stopper  24  and to terminate movement of the second elongate member  30  relative to the first elongate member  20  in the first direction M 1  as a result of the impact. 
         [0023]    In accordance with embodiments, the first resilient portion  42  may include a body  420  with a coupling side  421  and an impact side  422 . The body  420  is formed to define a borehole  423 , through which the third end  310  of the rod  31  of the second elongate member  30  may extend. In this way, during assembly of the bulb  40 , the first resilient portion  42  may be slid along the longitudinal length of the second elongate member  30  such that the coupling side  421  eventually registers with the leading side of the rigid element  41  with the impact side  422  facing away from the leading side of the rigid element  41 . At this point, the coupling side  422  can be screw-coupled or otherwise fastened to the leading side of the rigid element  41 . The impact side  422  has a curved surface that may complement a similar curvature in the interior facing surface of the second stopper  24 . As such, impacts between the impact side  422  and the second stopper  24  will be absorbed and deadened by a relatively large surface area of contact. 
         [0024]    In accordance with further embodiments, the second resilient portion  43  may include a body  430  with a coupling side  431  and an impact side  432 . The body  430  may be monolithic and the coupling side  432  can be screw-coupled or otherwise fastened to the trailing side of the rigid element  41 . The impact side  432  may have a curved surface that may complement a similar curvature in the surface of the first stopper  23 . As such, impacts between the impact side  432  and the first stopper  23  will be absorbed and deadened by a relatively large surface area of contact resulting in a reduced noise level without impacting the hole forming functionality of the ground-hole forming apparatus  10 . 
         [0025]    With reference to  FIG. 3 , a process of forming a ground-hole using the ground-hole forming apparatus  10  of  FIGS. 1 and 2  is provided. As shown, a bore-hole  100  is initially formed in the asphalt  102  and concrete  104  into the underlying ground  106  at a location where a gas leak is suspected of occurring. 
         [0026]    With reference to  FIGS. 4A and 4B , once the bore-hole  100  is formed, the fourth end  311  of the rod  31  of the second elongate element  30  is placed in the bore-hole  100  or on the ground at the surface of the bore-hole  100 . At this point, the operator of the ground-hole forming apparatus  10  grips the first elongate member  20  and forces the first elongate member  20  rapidly downwardly towards the ground such that the second elongate member  30  effectively moves in the second direction relative to the first elongate member  20  (see  FIG. 4A ). The downward movement of the first elongate member  20  continues until the second resilient member  43  impacts the first stopper  23  (see  FIGS. 1 and 2 ). From this point, the entire ground-hole forming apparatus  10  moves as a single unit downwardly (see  FIG. 4B ) due to the inability of the second resilient member  43  to pass through the first stopper  23  until the initial downward force applied by the operator dissipates or is ended. Thus, the fourth end  311  is driven into the ground at the bore-hole  100  by a driving distance DR to form the ground-hole  101 . In this manner, first elongate member  20  is configured as a driving element and second elongate member  30  is configured as a drivable element. 
         [0027]    With reference to  FIGS. 5A and 5B , once the initial downward force applied by the operator dissipates or is ended, the operator re-grips (if necessary) the first elongate member  20  and forces the first elongate member  20  upwardly away from the ground such that the second elongate member  30  effectively moves in the first direction relative to the first elongate member  20  (see  FIG. 5A ). The upward movement of the first elongate member  20  continues until the first resilient member  42  impacts the second stopper  24  (see  FIGS. 1 and 2 ). From this point, the entire ground-hole forming apparatus  10  moves as a single unit upwardly (see  FIG. 5B ) due to the inability of the first resilient member  42  to pass through the second stopper  24  until the initial upward force applied by the operator dissipates or is ended or until the fourth end  311  is removed from the lower-most region of the ground-hole  101 . 
         [0028]    Subsequently, the above-described process may be repeated with the fourth end  311  repeatedly being driven into the ground-hole  101  to increasing depths. The repetitions continue until a desired depth is reached or until a maximum depth based on the length of the rod  31  is achieved. 
         [0029]    While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

Summary:
A ground-hole forming apparatus is provided and includes a drivable element, a bulb coupled to an end of the drivable element and including first and second resilient portions, a driving element including first and second ends and being movable by an operator in first and second directions such that the first and second ends drivably impact the first and second resilient portions of the bulb, respectively, to thereby drive the drivable element in the first and second directions, respectively. The first and second resilient portions are configured to absorb and deaden respective impacts thereof with the first and second ends.