Abstract:
A trench blade having a unitary interchangeable leading edge, providing for the rapid replacement during usage. The blade is comprised of a steel body for attachment to a trench digging apparatus, wherein a replaceable hardened-steel front edge is mounted, allowing for the replacement thereof when the edge become worn or broken during over time. The edge is attached to the blade in a manner which allows the user to remove and replace the edge quickly and easily within a short period of time without removing the entire blade assembly from the trenching apparatus, thereby eliminating down time of the machine and improving job efficiency.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a trench digging apparatus. More particularly, this invention relates to a trench digging apparatus which utilize an earth-penetrating blade for creating a trench or installing underground conduits, featuring an easily serviceable/replaceable blade.  
       BACKGROUND OF THE INVENTION  
       [0002]     Earth digging and trenching apparatuses have been around for a long time and are designed to make short work of creating holes and trenches in the earth, soil, sand in comparison to manual digging with shovels and spades. Though there have been many variations and implementations over time to obtain such results, one of the most useful means for creating an elongated trench of a given distance comprises utilizing some type of land vehicle such as a tractor which has an earth penetrating means having a blade either pushed in front of it, or dragged behind it as it traverses the soil.  
         [0003]     By dragging the blade subterraneously as it moves along the surface of the ground, it can create a vertical trench of a predetermined depth, or can even draw a conduit for irrigation, electrical supply, fiber optic line or the like through the trench simultaneous to creating the trench itself, significantly cutting down on cost and labor.  
         [0004]     Because the soil of the earth is rarely consistent through any given application, various debris such as clay, sand, metal scraps and rocks of various sizes often come in contact with the trench blade. All of these result in significant wear to the blade, especially the leading edge thereby requiring the entire blade to be resharpened/replaced, sometimes frequently depending on the type of soil and how often the blade is used. Replacing the entire blade is a significant undertaking, and requires significant downtime for the machine, since the blade must be completely removed from the earth penetrating means of the vehicle prior to changeover.  
         [0005]     Since it is the leading edge of the blade which incurs the most wear and abrasion, it seems logical to have a trench digging blade wherein the leading edge can be replaced separate from the entire blade, and without having to disassemble the entire blade from the trench digging apparatus.  
         [0006]     U.S. Pat. No. 5,119,888 to Hall, discloses a Replaceable edge for a trenching plow blade, comprising a plurality of front-edge sections which attach to a mounting rod to be welded on the leading edge of the blade. The drawback to this design comes in having the leading edge comprised of a plurality of sections, this in conjunction with requiring a mounting rod to be welded to the blade lowers the integrity of the edge, which endures severe strains and impacts from various rocks and debris while in use. This could result in one or more sections prematurely being broke off from the trench blade, impairing its efficiency.  
         [0007]     There is thus a need for a trench blade having a replaceable, unitary leading edge for increased durability, allowing for the quick replacement thereof without having to remove the entire blade from the machine, thereby reducing the downtime, and increasing overall project efficiency.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention comprises a trench digging blade for attachment to a trenching apparatus of a vehicle, such as those depicted in the accompanying figures and known in the field of ground excavation. The blade is comprised of hardened steel or an alloy thereof and has an elongated, planar shape for extending down into the earth a predetermined depth by way of the trenching apparatus attached to the vehicle. The front edge of the blade, having a sharpened leading edge and also comprised of hardened steel or an alloy thereof is replaceable as a single unit.  
         [0009]     The replaceable edge is attached to the leading edge of the blade by means of machine hardware or locking pins, through corresponding mounting holes located in the blade and the replaceable edge. The edge further wraps around the earth engaging end of the blade, and extends a predetermined distance downward beyond the blade terminating in a pointed edge, for penetrating the ground during use. Overall downtime is minimized due to the edge being of a single piece, easily replaced without removing the entire blade from the trenching apparatus.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0011]      FIG. 1  is a partial side view of a trench digging machine having a first embodiment of the trench digging blade and removable edge attached thereto;  
         [0012]      FIG. 2  is a side view of the trench blade of  FIG. 1 , showing the replaceable edge attached to the blade;  
         [0013]      FIG. 3  is a side view of the replaceable edge of  FIG. 2  unattached to the trench blade;  
         [0014]      FIG. 4  is a side view of the trench blade of  FIG. 2  without the replaceable edge attached thereto;  
         [0015]      FIG. 5  is a partial side view of a trench digging machine having a second embodiment of the trench digging blade and removable edge attached thereto;  
         [0016]      FIG. 6  is a side view of the trench blade of  FIG. 5 , showing the replaceable edge attached to the blade;  
         [0017]      FIG. 7  is a is a side view of the replaceable edge of  FIG. 6  unattached to the trench blade; and  
         [0018]      FIG. 8  is a side view of the trench blade of  FIG. 6  without the replaceable edge attached thereto.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0020]     Referring to  FIGS. 1 and 5 , two variations are shown of trench digging vehicles  50  and  150  respectively, each having a manipulative trenching apparatus  100  and  200  attached thereto.  FIG. 1  illustrates a trenching apparatus  100  having a first embodiment of the trench blade assembly  110  with replaceable edge  130  attached there to, while  FIG. 5  illustrates a trenching apparatus  200  having a second embodiment of the trench blade assembly  210  with replaceable edge  230  attached thereto. Both embodiments function in substantially similar ways, and vary only in respect to their attachment means to the different trenching apparatuses  100  and  200 , depending on the specific one implemented on a given vehicle  50  or  150 .  
         [0021]     As shown in  FIGS. 1-4  illustrating the first embodiment of the trench blade assembly  110 , the present invention comprises two primary components; a trench blade  112  and a replaceable edge  130 . Shown combined in  FIG. 2  with the replaceable edge  130  but isolated for illustration purposes in  FIG. 4 , the trench blade  112  is formed of steel or a hardened alloy thereof and has a generally planar, elongated shape with an upper attachment end  114 , an earth penetrating end  120 , leading edge  118  and trailing edge  116 . The body of the blade  112  is angled, providing for better earth penetration, and improving the blades subterraneous angle of attack.  
         [0022]     In this first embodiment the attachment end  114  of the blade  112  is T-shaped, having spaced apart mounting apertures  113  and  115  there through for attachment to the trenching apparatus  100 . The earth penetrating end  120  further comprises a coplanar rear-projecting attachment tab  122  having aperture  117  there through, for attachment to a cable, wire, conduit or the like which may be simultaneously fed through the trench as the blade assembly  110  traverses through the earth. Additionally, a replaceable, forward facing inclined wedge element  126  is attached to the blade  112  on one or both sides of the blade  112  directly before the accessory aperture  117  diverting the ground and thereby reducing the frictional drag of any conduit being pulled through the ground, while also protecting the leading end of any conduit against damage from subterraneous debris.  
         [0023]     Referring now to  FIG. 3 , the replaceable edge  130  of the trench blade assembly  110  is a unitary, generally L-shaped element formed of hardened steel and extending along, and attaching to the leading edge  118  of the trench blade  112 . The replaceable edge  130  has a lower end which extends beyond the earth penetrating end  120  of the blade  112  terminating in a point  136 , thereby aiding in penetrating the ground. The trailing edge of the point  136  extends back along the earth penetrating end  120  of the blade  112  and terminates proximal the trailing edge  116  of the blade. Both the front side  132  and point  136  are beveled to a sharpened edge, providing for easier subterraneous movement of the blade assembly  110 .  
         [0024]     The back side  131  of the replaceable edge  130  comprises mounting tabs  134 , 138  and  140 , having attachment apertures  135 ,  137 , and  139  there through, which associate with and attach to mounting portion  124  and front edge  118  of the blade  112  through apertures  119 ,  121 , and  123  therein. The attachment hardware utilized may be any removable hardened machine screws or locking pin arrangement which provides a secure attachment through the corresponding apertures to attach the replaceable edge  130  to the blade  112 , but can easily be removed once the replaceable edge is worn and requires refurbishing or replacement.  
         [0025]     Now referring to  FIGS. 5-8 , similar in function to the first embodiment of the trench blade assembly  110 , the second embodiment also comprises two primary components; a trench blade  212  and a replaceable edge  130 . Shown combined in  FIG. 6  with the replaceable edge  230  but isolated for the purpose of illustration in  FIG. 8 , the trench blade  212  is formed of steel or a hardened alloy thereof and has a generally planar, elongated shape with an upper attachment end  114 , an earth penetrating end  220 , leading edge  218  and trailing edge  216 . The body of the blade  212  is angled, providing for better earth penetration, and improving the blades subterraneous angle of attack.  
         [0026]     In this second embodiment the attachment end  214  of the blade  212  has longitudinally spaced apart mounting apertures  213  and  215  there through for attachment to the trenching apparatus  200 . The earth penetrating end  220  further comprises a coplanar rear-projecting attachment tab  222  having aperture  217  there through, for attachment to a cable, wire, conduit or the like which may be simultaneously fed through the created trench as the blade assembly  210  traverses through the earth. Additionally, a forward facing inclined wedge element  226  is replaceably attached to the blade  212  on one or both sides of the blade  212  directly before the accessory aperture  217  diverting the ground, thereby reducing the frictional drag of any conduit being pulled through the ground while also protecting the leading end of any conduit against damage from subterraneous debris.  
         [0027]     Referring now to  FIG. 7 , the replaceable edge  230  of the trench blade assembly  210  is a unitary, generally L-shaped element formed of hardened steel and extending along, and attaching to the leading edge  218  of the trench blade  212 . The replaceable edge  230  has a lower end which extends beyond the earth penetrating end  220  of the blade  212  terminating in a point  236 , thereby aiding in penetrating the ground. The trailing edge of the point  236  extends back along the earth penetrating end  220  of the blade  212  and terminates proximal the trailing edge  216  of the blade. Both the front side  132  and point  136  are beveled to a sharpened edge providing for easier subterraneous movement of the blade assembly  210 .  
         [0028]     The back side  231  of the replaceable edge  230  comprises a mounting tabs  234 ,  238  and  240 , having attachment apertures  235 ,  237 , and  239  there through, which associate with and attach to mounting portion  124  and front edge  218  of the blade  212  through apertures  219 ,  221 , and  223  therein. The attachment hardware utilized may be any removable hardened machine screws or locking pin arrangement which provides a secure attachment through the corresponding apertures to attach the replaceable edge  230  to the blade  212 , but can easily be removed once the replaceable edge is worn and requires refurbishing or replacement.  
         [0029]     In both embodiments described above, the replaceable edges  130 / 230  are single, unitary formed elements, which provide greater strength and resistance from impacts with subterraneous debris, and allow for a more rapid change out when replacement is needed. When such an event is required, the user simply manipulates the trenching apparatus  100 / 200  out of the ground so as to expose the entire blade assembly  110 / 210 . Without removing the assembly  110 / 210  from the corresponding trenching apparatus, the user can remove the hardware attaching the replaceable edge  130 / 230 , to the blade  112 / 212 ; replace the worn edge with a new or refurbished edge  130 / 230  utilizing either the original or new hardware, and return the trench blade assembly back into the ground to continue trenching with just a brief downtime delay, thereby significantly increasing efficiency.  
         [0030]     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.