CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority to provisional application No. 61/090,490 filed Aug. 20, 2008, entitled Vibratory Plow Assembly, which is incorporated by reference in its entirety herein. 
     
    
     FIELD OF THE INVENTION  
       [0002]    This disclosure relates generally to a plow assembly for cutting a slit in the ground. More particularly, this disclosure relates to a plow assembly having a rotating mass for creating vibrations which are transmitted to the plow blade to provide increased efficiency. 
       BACKGROUND  
       [0003]    Cables, conduits, and other services are often installed in relatively shallow underground trenches. For example, electrical lines (direct burial and/or conduit), telephone wiring/fiber optic, television cables, natural gas lines, and drainage lines are often buried in this manner. Additionally, drip irrigation lines and other types of conduits and lines can be installed underground. These lines, conduits, and pipes will be collectively referred to herein as “utility lines” for convenience. 
         [0004]    These lines are often installed with a plow assembly, with such plows generally well-known in the art. Examples of such plows are described in U.S. Pat. No. 3,935,712; U.S. Pat. No. 4,102,403; and U.S. Pat. No. 4,337,712. These plows generally include a plow blade supported at the rear of the plow assembly. As used herein, the terms “front” and “rear” shall be with reference to the direction that the plow assembly moves during operation. As the plow blade is advanced through the ground, a narrow trench is created in which the utilities are laid. Initially, the act of creating the trench, installing the utility lines, and covering the trench were three separate acts. However, plow assemblies have advanced so that the utility lines are laid into the trench at the rear of the plow blade as the plow blade is advanced through the ground. Further, the plow assembly is designed such that any spoils from the trench are reintroduced into the trench and tamped by trailing tamping feet/wheels. In this manner, the utility lines are installed into the ground in a single pass over the ground by the plow assembly. 
         [0005]    The energy needed to install utility lines depends on the desired depth, size of the utility lines, and the ground (soil) conditions (Clay, sand, loam, etc.). In hard conditions, the process may be slow and require a large amount of power from the tractor/plow assembly motor to pull the plow blade through the ground. To reduce this loading, various efforts have been made including injecting liquid to the plow blade and to the utility lines being installed to moisten and soften the ground. Other prior art plow assemblies have utilized rotating masses to impart a vibratory movement to the plow blade. However, even using these two methods, the rate at which the plow assembly can be advanced over the ground can still be relatively slow. Therefore, there is a need in the art for a method and apparatus for improving the efficiency in which the plow blade can be advanced through the earth. The present invention overcomes the shortcomings of the prior art. 
       SUMMARY  
       [0006]    The present disclosure generally relates to a method and apparatus for installing utility lines underground by using a vibratory plow. One aspect of the invention relates to using a resilient member attached to a vibrator assembly, where the resilient member stores the kinetic energy of the vibrator assembly downward movement. The kinetic energy is then released during the upward movement. The energy is applied to a plow blade so as to improve the efficiency of the plow blade as it is drawn through the ground. Another aspect of the invention relates to connecting the resilient member to the ground via a set of wheels that do not appreciably deflect during the downward movement. 
         [0007]    While the invention will be described with respect to preferred embodiment configurations and with respect to particular devices used therein, it will be understood that the invention is not to be construed as limited in any manner by either such configurations or components described herein. Also, while particular types of special links are described herein, it will be understood that such particular mechanisms are not to be construed in a limiting manner. Instead, the principles of this invention extend to any environment in which kinetic energy is stored during the downward movement of the rotating masses and then utilized during the upward movement. These and other variations of the invention will become apparent to those skilled in the art upon a more detailed description of the invention. 
         [0008]    The advantages and features which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. For a better understanding of the invention, however, reference should be had to the drawings which form a part hereof, and to the accompanying descriptive matter in which there is illustrated and described a preferred embodiment of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES  
         [0009]      FIG. 1  is a side view of a plow assembly according to an embodiment of the present disclosure with the plow blade in the retracted position; 
           [0010]      FIG. 2  is a side view of the plow assembly of  FIG. 1  with the plow blade in an extended position; 
           [0011]      FIG. 3  is an enlarged view of a portion of  FIG. 2 ; 
           [0012]      FIG. 4  is a perspective view of a portion of the plow assembly of  FIG. 1 ; 
           [0013]      FIG. 5  is a side view of the portion of the plow assembly shown in  FIG. 4 ; 
           [0014]      FIG. 6  is a cross-sectional view of the plow assembly along line  6 - 6  of  FIG. 5 ; 
           [0015]      FIG. 7  is a rear view of the portion of the plow assembly shown in  FIG. 4 ; 
           [0016]      FIG. 8  is a cross-sectional view of the plow assembly along line  7 - 7  of  FIG. 7 ; 
           [0017]      FIG. 9  is a front view of the portion of the plow assembly shown in  FIG. 4 ; 
           [0018]      FIG. 10A  is a side schematic view of the plow assembly in a first position; 
           [0019]      FIG. 10B  is a side schematic view of the plow assembly in a second position; 
           [0020]      FIG. 11  is a side schematic view of a first alternative embodiment of the plow assembly of  FIG. 1 ; 
           [0021]      FIG. 12  is a side schematic view of another alternative embodiment of the plow assembly of  FIG. 1 ; 
           [0022]      FIG. 13  is a side schematic view of another alternative embodiment of the plow assembly of  FIG. 1 ; 
           [0023]      FIG. 14  is a side schematic view of another alternative embodiment of the plow assembly of  FIG. 1 ; 
           [0024]      FIG. 15  is a side schematic view of another alternative embodiment of the plow assembly of  FIG. 1 ; 
           [0025]      FIG. 16  is a side schematic view of another alternative embodiment of the plow assembly of  FIG. 1 ; 
           [0026]      FIG. 17  is a side schematic view of another alternative embodiment of the plow assembly of  FIG. 1 ; 
           [0027]      FIG. 18  is a side schematic view of another alternative embodiment of the plow assembly of  FIG. 1 ; 
           [0028]      FIG. 19  is a side schematic view of another alternative embodiment of the plow assembly of  FIG. 1 ; and 
           [0029]      FIG. 20  is an enlarged portion of an alternative embodiment showing a torsion axle; 
           [0030]      FIG. 21  is a side view of the torsion axle embodiment in a retracted position; 
           [0031]      FIG. 22  is a side view of the torsion axle embodiment in an extended position; 
           [0032]      FIG. 23  is an enlarged view of a portion of  FIG. 22 ; 
           [0033]      FIG. 24  is a perspective view of the torsion axle connected to the vibratory mechanism; 
           [0034]      FIG. 25  is a rear view of the torsion axle connected to the vibratory mechanism; 
           [0035]      FIG. 26  is a side view of the torsion axle connected to the vibratory mechanism; 
           [0036]      FIG. 27  is a cross-sectional view along line  27 - 27  of  FIG. 26 ; and 
           [0037]      FIG. 28  is a cross-sectional view along line  28 - 28  of  FIG. 25 . 
       
    
    
     DETAILED DESCRIPTION  
       [0038]    Referring to  FIGS. 2 and 3 , an embodiment of the vibratory plow system according to the present disclosure is shown. The system  10  includes a vehicle  12 , a vibratory plow assembly  14 , and a connection linkage  16  that connects the vibratory plow assembly  14  to the rear of the vehicle  12 . 
         [0039]    In the depicted embodiment the vehicle is a tracked machine, but it should be appreciated that in alternative embodiments many other types of vehicles may be used to drag the plow assembly. In the depicted embodiment the linkage  16  is a four bar type linkage that is actuated by a hydraulic cylinder  18  that extends and retracts the plow assembly  14 .  FIG. 1  shows the linkage  16  in the retracted position (disengaged position), and  FIG. 2  shows the linkage  16  in the extended position (engaged position). In the depicted embodiment the linkage  16  is configured to pivot horizontally about the vehicle at the connection location  20  between the linkage  16  and the vehicle  12 , and allow the plow assembly  14  to pivot about the linkage  16  about the connection location  22 . Hydraulic cylinders  24  and  26  are provided for actuation of the linkage  16  relative to the vehicle  12  and the linkage  16  relative to the plow assembly  14 . It should be appreciated that may other linkage configurations are also possible. 
         [0040]    Referring to  FIGS. 3-9  the plow assembly  14  is shown in greater detail. In the depicted embodiment the plow assembly  14  includes a vibration device  28  that is configured to be attached to the linkage  16 , a plow blade  30 , and two adjacent rollers  32 ,  34 . The use of two adjacent rollers can be advantageous over a single roller in some embodiments as cables can be easily attached to the plow blade  30  via the gap between the rollers. However, it should be appreciated that any other number of rollers may be included in alternative embodiments of the present disclosure. 
         [0041]    The rollers  32 ,  34  of the depicted embodiment are connected to the vibration device in an identical manner, and can move independent from each other. For simplicity, the connection assembly for only one of the rollers  32 ,  34  will be described herein. In the depicted embodiment, the roller  32  is connected to the lower portion of the vibration device  28  via a pair of pivot arms  36 ,  38 . The distal ends of the pivot arms  36 ,  38  are connected to the axel  40  and the proximal ends  42 ,  44  of the pivot arms  36 ,  38  are connected to the vibration device  28 . In the depicted embodiment the proximal ends are connected to a torsion bushing  46 . It should be appreciated that in alternative embodiment the torsion bushing could be replaced with a torsion axle. 
         [0042]    In the depicted embodiment the torsion bushing  46  and pivot arms  36 ,  38  are configured to accommodate a significant amount of vertical displacement, (also known as travel). In the depicted embodiment the travel is be between about 0 to 4 inches. More preferably, the travel is between about ½-1 inches. In the depicted embodiment the plow blade  30  is directly mounted to the vibration device  28 . It should be appreciated that in other embodiments the plow blade  30  is mounted to the vibration device in a manner that allows the blade  30  to move relative to vibration device  28 . In the depicted embodiment the vertical displacement of the vibration device  28  can be caused by the vibrations generated by the vibration device  28  in the vertical direction and/or caused by the plow blade  30  moving in the vertical direction as the plow blade  30  comes into contact with rocks and other materials in the ground. 
         [0043]    Referring to  FIGS. 10A and 10B , the movement of the pivot arms  36 ,  38  are shown relative to the vibration device  28  and plow blade  30 . When the plow blade  30  and vibration device  28  are in the peak position (relative high position) as in  FIG. 10A , the energy stored in the torsion bushing  46  is release. Conversely, when the plow blade  30  and the vibration device  28  move in valley (relative low position) as in  FIG. 10B , the energy is loaded into the torsion bushing  46 . The vertical movement to plow blade  30  oscillates from peaks to valleys. 
         [0044]    The configuration of the present disclosure results in a smoother, more efficient cut through the ground as it does not significantly dampen the vibration in the lateral direction and more efficiently uses the vibrations in the vertical direction. To provided a quantitative measure of some of the performance advantages associated with the present disclosure, a prior art vibratory plow system was compared to a comparably side by side with a powered system that incorporated features of the present disclosure. 
         [0045]    In particular, the performance of a prior art vibratory plow with tamping feet and without a torsion bushing in the configuration described above was measured. Based on five trial runs the average feet per minute was 15.5 feet/min with a standard deviation of 9.5 feet/min. The performance of a comparably powered vibratory plow system with the above described rollers and torsion bushing was also measured. Based on five trial runs the average feet per minute was 115.4 feet/min with a standard deviation of 20.0 feet/minute. In view of the above test, it is evident that present disclosure provides a significantly faster system as compared to the prior art. It is believed that the improved performance is in part a result of the plow blade having more energy on the up stroke. It should be appreciated that the relative performance advantages associated with the plow system of the present disclosure over prior art systems is most evident in compressed soil conditions (i.e., difficult to plow soil). In compressed soil condition, the plow system according to the present disclosure imparts relatively less load on the pulling vehicle than system of the prior art. 
         [0046]    Referring to  FIGS. 11-19 , other alternative embodiments of the present disclosure are shown.  FIG. 11  illustrates an embodiment that includes a cylinder  50  (e.g., air, hydraulic) that can be used in place of or in conjunction with the torsion bushing.  FIG. 12  illustrates an embodiment that includes a cylinder and spring arrangement  52  that can be used in place of or in conjunction with the torsion bushing.  FIG. 13  illustrates an embodiment that includes a leaf spring arrangement  54  that can be used in place of or in conjunction with the torsion bushing.  FIG. 14  illustrates an embodiment that includes an air bag arrangement  56  that can be used in place of or in conjunction with the torsion bushing.  FIG. 15  illustrates an embodiment that includes a spring arrangement  58  that can be used in place of or in conjunction with the torsion bushing. In the depicted embodiment the spring is located on the opposite side of the pivot point  60  between the roller  62  and the vibration device. 
         [0047]      FIG. 16  illustrates an embodiment that includes a pair of cylinders  64 ,  66  located on either side of the vibration device  28  that can be used in place of or in conjunction with the torsion bushing.  FIG. 17  illustrates an embodiment that includes a pair of cylinders and spring arrangements  68 ,  70  located on either side of the vibration device  28  that can be used in place of or in conjunction with the torsion bushing.  FIG. 18  illustrates an embodiment that includes a pair of leaf springs  72 ,  74  located on either side of the vibration device  28  that can be used in place of or in conjunction with the torsion bushing.  FIG. 19  illustrates an embodiment that includes a pair of air bags  76 ,  78  located on either side of the vibration device  28  that can be used in place of or in conjunction with the torsion bushing. 
         [0048]    Referring to  FIGS. 20-28  shows an embodiment of the plow system with a torsion axle  80  in place of the torsion bushing  46 . In the depicted embodiment the torsion axle  80  connects the wheels  82 ,  84  to the vibratory device  86 . In the depicted embodiment the torsion axle is a resilient member that interfaces between the wheels and the vibratory device. In the depicted embodiment, the position between the wheels  82 ,  84  and the torsion axis can be adjusted via adjustment nuts  90  on bolts  88 . Adjusting the adjustment nuts  90  pivots the wheels  82 ,  84  about the adjustment pivot axis  94 . Once the adjustment nuts  90  are set the wheels  82 ,  84  are arranged to pivot about the main pivot axis  96  in use. In the depicted embodiment the torsion axle  80  is mounted to the vibratory device  86  via a bracket assembly  98 . It should be appreciated that in alternative embodiments, the embodiments including torsion axles can be configured in many alternative arrangements. 
         [0049]    Referring to  FIGS. 21-28 , the above-described embodiment including a torsion axle is shown as part of a complete plow system. Many of the features are similar to the features of the above-described system; therefore, they are not described again herein. 
         [0050]    The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.
The present disclosure generally relates to a method and apparatus for installing utility lines underground by using a vibratory plow. One aspect of the invention relates to using a resilient member attached to a vibrator assembly, where the resilient member stores the kinetic energy of the vibrator assembly downward movement. The kinetic energy is then released during the upward movement. The energy is applied to a plow blade so as to improve the efficiency of the plow blade as it is drawn through the ground. Another aspect of the invention relates to connecting the resilient member to the ground via a set of wheels that do not appreciably deflect during the downward movement.