Patent Publication Number: US-6659195-B2

Title: Externally vented drive head with solid center

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to soil sampling apparatus, and more particularly to a solid head means that prevents soil from entering hollow drive rods attached to the head means. 
     BACKGROUND OF THE INVENTION 
     Geological sampling apparatus for surveying ground soil are well known. Such apparatus usually includes a sampling probe fastened to the lower end of a first drive rod while successive drive rods are serially connected to the first rod to provide a vertical distance appropriate for the level in the ground and earth at which a soil sample is sought. The probe and serially connected rods are directly driven into the ground by a suitable power source such as a hydraulic cylinder. The rods are made of a high strength durable steel. 
     “Direct push” soil sampling apparatus presently uses an elongated sampling tube connected to the first, lower most hollow rod by an open center head, i.e., the head has a lower nipple section or portion that attaches to the elongated sampling tube while an upper nipple portion of the head is mechanically connected to the lower end of the lowermost hollow drive rod or directly to the driving power source. When the drive rods and power source thrust the sampling tube into the ground the tube can fill with loose soil or wet mud and water as air in the tube is expelled through the open center head and up through the hollow rods. As the driving process continues, loose, wet soil travels up through the open center head and hollow rods where the soil compacts in the rods. 
     The sampling tube and connecting head are also made of a high strength durable steel as is a lower soil penetrating shoe discussed hereinafter. 
     Direct push soil sampling apparatus employs a hydraulic cylinder to directly drive (hammer) connecting drive rods, sampling tube, and head into the ground. U.S. Pat. No. 5,606,139 to Kejr is an example of the direct push or drive apparatus. The hollow connecting rods of the apparatus are used to receive internal tooling. One set of such tooling includes serially connected rods (not shown) inserted into and through the hollow rods to a lower pointed plug (not shown) moved into place in a cutting shoe connected to the lower end of the sampling tube by actuation of the solid rods for the purpose of keeping soil from entering the sampling tube during its downward thrust into the ground to the depth and location of sampling. 
     Another set of tooling involves the insertion of small diameter tubing into the hollow rods for the purpose of pumping water from the bore hole created by the sampling assembly when driven into the ground. 
     When the connecting rods are compacted internally with soil the tooling obviously cannot be used until the soil is removed, and the process of removing the compacted soil can be extremely difficult. Hammering and beating on the hollow rods is often the method used to remove the soil. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention uses a drive head having a solid body that prevents any travel of mud and soil into the hollow drive rods. Rather, air is vented and expelled from the head when it enters the ground by at least one passageway that extends from a lower portion of the head to an upper sloping surface of the head, the head having a body portion in the configuration of a truncated cone. The cone has a narrow upper end provided with a threaded nipple for attaching to a hollow drive rod while the lower, broader end of the cone has a threaded nipple for connecting to and supporting the soil sampling tube. As the tube and head are driven into the ground a vertical bore hole is created in the ground and earth while loose soil or mud enters the tube as air is vented into the bore hole. The air travels upwardly through the bore hole to the atmosphere above ground. When the above internal tooling is required; the solid head of the invention is removed from the sampling apparatus and replaced by the prior hollow head. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention, along with its advantages and objectives, will be best understood from consideration of the following detailed description and the accompanying drawings in which: 
     FIG. 1 is an exploded, somewhat schematic presentation of a prior art direct push soil sampling assembly and apparatus in which a hydraulic cylinder is mechanically connected to serially connected rods, the lowermost rod of the apparatus mechanically connected to head means which, in turn, supports a soil sampling tube; 
     FIG. 2 is an elevation view of a solid head structure of the present invention showing, inter alia, a truncated cone portion of the head and a venting passageway (in phantom) extending to one side of the cone; 
     FIG. 3 is an elevation view of a second embodiment of the head of the invention in which the venting passageway is bifurcated to provide two venting avenues to an upper outside surface of the head. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1 of the drawings, a direct push soil sampling system and apparatus is shown in exploded form and is labeled by reference numeral  10 . More particularly, assembly  10  comprises a hydraulic cylinder  12  (only diagrammatically shown) mechanically connected to a first hollow drive or push rod  14 , though the hydraulic cylinder can initially be connected directly to a drive head  16  and a sampling tube  22  for initially driving the tube into the ground. After the sampling tube is driven into the ground, drive rods  14  can be added as needed. 
     Push or drive rod  14  represents a plurality of such rods and is broken away diagrammatically in its longitudinal center in FIG. 1 to reduce the size of the figure so that it can be confined to one sheet of drawing. Such rods  14  themselves can be of unspecified length but are usually three to four (or more) feet long, with the ends thereof threaded for connecting to each other in a serial manner. 
     The lower end of the lowermost hollow rod  14  is internally threaded (not visible in FIG. 1) to thread onto an upper externally threaded integral nipple  15  of a prior art, open center drive head  16 . Head  16  includes, in addition a lower externally threaded nipple  20  for threadably connection to an internally threaded upper end of an elongated soil sampling tube  22 . 
     The interior of the head including its threaded nipples are open throughout the length of the head and nipples as indicated by numeral  18  in FIG.  1 . 
     Like the drive or push rods of  14 , sampling tube  22  can be three to four feet long so that in FIG. 1 the tube is also broken away diagrammatically to fit assembly  10  on a single sheet of drawing. 
     The lower end of sampling tube  22  is shown provided with internal threads for threading to a cutting shoe  24  having a beveled, sharp end  26  for penetrating the ground when the rods, head, tube, and shoe are driven downwardly by hydraulic cylinder  12 . Cylinder  12  is usually a hydraulic jack hammer that provides downwardly driving pulsating thrusts to rods  14 . 
     When cutting shoe  24  and sampling tube  22  are driven into the ground and earth by cylinder  12  soil enters the tube so that air in the tube and in head  16  is vented upwardly through the tube and head (via opening  18  in the head) and through hollow rods  14  (when added) to atmosphere. As the driving process continues, soil can enter opening  18  in hollow head  16  and travel through the head to and into rods  14 . For the reasons given above, any soil in the rods must be removed, and removal can be a tedious and laborious process. 
     The present invention replaces open center head  16  with a solid head  28 , as shown in FIGS. 2 and 3 of the drawings, having a solid body  30  so that no soil, mud, or water can enter hollow tubes  14 . A passageway  32  is provided in the solid body of the head in FIG. 2 permit venting of the air in sampling tube  22  and in head  28  to the bore hole (not shown) created in the earth when shoe  24 , and  22 , and head  28  are driven into the earth. From such bore hole, air is vented to atmosphere. The bore hole above head  16  is the width of the widest portion of the head so that there is ample room above the head and around rods  14  for the venting of air in tube  22  and head  28 . A typical diameter of sampling tube  22 , shoe  24 , and the lower nipple end  20  of the head is about two inches, whereas the diameter of rods  14  is on order of one inch. 
     The lower nipple end of head  28  transitions upwardly to the upper nipple  15  such that an intermediate body portion  34  of the head is that of truncated cone, with the narrow end of the cone being at the nipple end  15  while the broader end of the cone is at the lower end of the head adjacent nipple  20  when the head is in the vertical position shown in drawing FIGS. 2 and 3. 
     Passageway  32  can be provided in the solid body of head  28  by a number of manufacturing methods including forging, machining or drilling. 
     FIG. 2 of the drawings shows, in addition, a check valve  36  located in passageway  32 , the purpose of which is to prevent removal of the soil sample (not shown) in tube  22  from being drawn out of the tube and through head  28  when apparatus  10  is pulled from the earth after the sample is taken, i.e, as tube  22  and head  28  are pulled from the bore hole created in the ground, reduced air pressure occurs that can ordinarily suck at least a portion of the soil sample from the tube. Valve  36  is kept open during the driving process by air passing between a ball  35  and its seat  37  (FIG. 2) which keeps the ball from its seat so that the air in tube  22  can escape. The sucking action during removal of the sampling apparatus from the bore hole drives the ball against its seat to prevent removal of the soil sample from the tube. 
     After the apparatus of  10  is removed from the ground, sample tube  22  is unthreaded from head  28  so that the soil sample can be removed from the tube for analysis. 
     FIG. 3 of the drawings shows an embodiment of the invention in which venting passageway  32  is divided or bifurcated at  38  in head  28  to provide more than one passageway that extends to at least two ports  40  and  42  on the surface of intermediate cone  34 . Like the single passageway  32 , the divisions or bifurcations of the passageway can be provided when the head is machined, or by drilling. 
     While the invention has been described in terms of preferred embodiments, the claims appended hereto are intended to encompass all embodiments that fall within the spirit and scope of the invention.