Abstract:
Methods and apparatus for cutting a trench (e.g., for a fiber optic cable or wire conductors) in an existing covering surface (e.g., a road surface). Debris from the cut trench is evacuated (e.g., vacuumed) from the trench as the trench is cut. The trench may be backfilled using a flowable composition. In one example, the flowable composition rigidifies after being flowed into the trench, and thereafter is substantially impermeable (e.g., having a hydraulic permeability of less than 0.0000001 cm/s upon drying), non-compressible and/or non-expanding.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit, under 35 U.S.C. §120, as a continuation (CON) of U.S. Non-provisional Ser. No. 13/796,391, filed Mar. 12, 2013, entitled “Laying and Protecting cable into Existing Covering Surfaces.” 
         [0002]    U.S. Non-provisional Ser. No. 13/796,391, filed Mar. 12, 2013, claims the benefit, under 35 U.S.C. §120, as a continuation (CON) of U.S. Non-provisional Ser. No. 12/889,196, filed Sep. 23, 2010, entitled “Laying and Protecting cable into Existing Covering Surfaces.” 
         [0003]    U.S. Non-provisional Ser. No. 12/889,196, filed Sep. 23, 2010, in turn claims the benefit, under 35 U.S.C. §119(e), of U.S. Provisional Ser. No. 61/244,954, filed Sep. 23, 2009, entitled “Laying and Protecting Cable into Existing Covering Surfaces.” 
         [0004]    Each of the above-identified applications is hereby incorporated herein by reference. 
     
    
     BACKGROUND 
       [0005]    Problems are encountered when attempting to lay the “last mile” of underground cables such as, for example, a fiber optic cable or an electrical cable. The problem is accentuated in urban areas due to the dense build-out of the surrounding area, traffic congestions, and on-going road repairs occurring in urban areas. 
         [0006]    Such cables may or may not be enclosed in a pipe or a conduit depending on customer needs. One or more cables may be enclosed in such a pipe or conduit depending on customer needs. 
         [0007]    Prior systems used for the construction of underground paths for the insertion of underground cable were cumbersome. For example, operators had to make multiple passes to cut a slot prior to adequate insertion of the cable. 
       SUMMARY 
       [0008]    An efficient system and method for laying the “last mile” of underground cables creating minimal disruption to property owners or less impact to the neighborhood is needed. 
         [0009]    The following steps are carried out in the system and method. First, cut and immediately evacuate a void in the existing covering surface. Next, lay or apply cable(s) (cable, ducts and/or conduits) into the void (i.e. underground). Then, flow a non-shrinking composition into a portion of the void around the cable to fill a portion of the void. Upon rigidification the cable is encased in the void by the non-shrinking composition. Last, apply a topping material to the exposed surface of the composition in such volume as to fill any remaining portion of the void. This seals the void now filled with an underground cable line as encased by the composition. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is an elevation view of a cutting and evacuating machine making a channel through the covering surface in a neighborhood. 
           [0011]      FIG. 2  is an elevation view of a grouting machine flowing grout into the channel of the covering surface within a neighborhood. 
           [0012]      FIG. 3  is a sectional view of a channel through a covering surface filled with cables, grout and topping material. 
           [0013]      FIG. 4  is a perspective view of one embodiment cutting and evacuating a void in an existing covering surface within a neighborhood. 
           [0014]      FIG. 5  is an elevation view of an embodiment of a portable cutting and evacuating machine with the blade of the cutter raised for inspection or transport. 
           [0015]      FIG. 6  is a schematic view in section of an embodiment of a cutter and vacuum system cutting and evacuating a void which is being cut into an existing covering surface. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Referring to  FIG. 1 , an underground cable line ( FIG. 3 ) may be constructed or installed into an existing covering surface  10 . The covering surface  10  is normally pre-existing and hence the challenge for construction of the underground cable line. Such existing covering surface  10  could be, but is not limited to, pavement, paving, concrete, asphalt, blacktop, cobblestone, brick, other road base, grade or surface, or the like, or any combination of the foregoing (e.g. combination of asphalt laid over concrete). 
         [0017]    To construct the underground cable line, operator(s) cut and evacuate a void, channel or passage  12  into the existing covering surface  10  (having sub-surface  11 ). It is advantageous to avoid making multiple passes (as done in prior systems) in order to cut the void  12 . Therefore the void  12  is cut in one and only one pass or swath from, referring to  FIG. 4 , a first position or starting point A to a second position or finishing point B (which may, for example, be separated by some kilometers or in another example by 45.72 meters (150 feet), i.e., cut in one and only one pass by a distance more than a few centimeters). Some of the advantages to using this technique include that the base is not disturbed as with multiple passes; less time is consumed in construction the void; the void is constructed with a simple uniform cut. Therefore the technique of cutting the void  12  in one and only one pass is quite advantageous. 
         [0018]    One embodiment of a machine  30  which may be used to cut and evacuate in one and only one swath includes, for example, a cutter  32  with a narrow rotating blade  33  ( FIG. 5 ) that will cut the existing covering surface  10  leaving a void  12  behind. The machine  30  is portable via, for example, wheels  38  ( FIG. 5 ), and has an operator control station  39 . Operator control station  39  ( FIG. 5 ) includes a seat for the operator and a steering wheel to turn the machine  30 . Each of the wheels  38  has an inner sidewall, an outer sidewall, and a circumferential area that contacts the covering surface  10 . The circumferential area of each of the wheels  38  may include a grooved portion with a groove extending from the outer sidewall to the inner sidewall and may also include a portion free of grooves that is substantially free of tread. Outer sidewall and inner sidewall of wheels  38  may be substantially planar. 
         [0019]    Accompanying the cutter  32 , the machine  30  also immediately cleans or evacuates the void  12  such as by blowing, vacuuming, and/or sweeping the void  12 . In the embodiment shown, a vacuum system  34  (e.g., including two evacuation ducts  50 A and  50 B and a Y-duct  51 ) accompanies the cutter  32  and is partially mounted to the machine  30 . Preferably, but not limited to, the vacuum system  34  is in juxtaposition with respect to the cutter  32  and is mounted upper-lower, respectively and in relation to the cutter  32  such that the step of vacuuming occurs concurrent with the step of cutting the void  12 . The vacuum system  34  may be connected to an independent portable vacuuming system  36  ( FIG. 4 ) mounted to a vehicle and connected via a Y-duct  51 . 
         [0020]    In cutting the void  12  the action of the cutter  32  cuts and moves material and/or soil from the covering surface  10 . this creates a stream or volume of debris (designated by arrows  18 ,  FIG. 6 ) that generally has momentum from and travels in the direction of the cutter  32  (at least initially). The vacuum system  34  in juxtaposition to the cutter  32  concurrently, immediately and directly suctions the stream of debris  18  (preferably all or at least substantially all of the debris  18 ) through an inlet shroud  35  that includes one or more vents  37  and which overlaps the path of the stream of debris  18 . This prevents the stream of debris  18  (containing cuttings, remnants, and/or excavated matter from the covering surface  10 ) from diffusing, circling with, and or recycling with the cutter  32  back into the void  12  and from creating dust in general. In the embodiment shown, the cutter  32  actually assists in moving the stream of debris around and into the cubic feet per second airflow suction of the vacuum system  34 . 
         [0021]    The blade  33  of the cutter  32  must have a width and diameter sufficient to cut a void  12  having a width and depth as follows. The width of the void  12  should be narrow, i.e., as narrow as possible to fit cable(s) or duct(s)  14  within the void  12 . This allows vehicles to traverse the void  12  while the underground cable line is being constructed at the installation site. One example of an acceptable width is 1.75 cm ( 11/16ths of an inch). For purposes of limiting the changing of the cutter  32  blade  33  it may be useful to offer standard width voids/channels  12 , and normally the width of the void  12  will be selected from either a range of 1.9 cm to 2.54 cm (0.75 in.-1 in. wide), or a 3.175 cm (1.25 in.) wide void. However, the width of the void  12  is not limited to these certain standard ranges. The width of the void  12  should be less than about 3.8 cm (1.5 inches) in any case and preferably less than or equal to 3.175 cm (1.25 in.). It has been discovered that if the width of the void  12  is too large, the asphalt will not properly bridge making the disclosed technique ineffective. On the lower end, voids  12  having a width of 1.27 cm (0.5 in.) have been successfully implemented, but 1.27 cm (0.5 in.) is not necessarily limiting at the lower end. 
         [0022]    The void  12  must be greater than 10.16 cm (four inches) deep into the covering surface  10 . Presently the preferred depth of the void  12  is 30.48 cm (twelve inches) deep. This avoids the penetration of existing utility lines (and further thereby speeds the permitting process). Excessive depth of the channel may inhibit evacuation of the cuttings or penetrate to undesirable areas but otherwise the depth of void  12  is not limited. 
         [0023]    As described above the evacuating step pertains to the removal from the void  12  of any cuttings, etc. in the stream of debris  18  resulting from the cutting of the existing surface  10 . Vacuuming simultaneously or instantaneously with the cutting of the void  12  is critical or quite advantageous to the effectiveness of the technology. By suctioning while cutting less dust is created, the action of the moving volume of air cools the cutting blade  33 , removes materials that could create greater friction on the spinning blade  33 , and creates a void  12  free of loose debris/cuttings. Vacuuming is one example of a procedure to be used for evacuating. 
         [0024]    One embodiment of a machine  30  which is acceptable for use for carrying out the steps of cutting and evacuating is commercially available from DITCHWITCH of Perry, Okla., USA. 
         [0025]    The cable(s) (cable, ducts and/or conduits)  14  must be laid or applied into the void  12 . This may be performed by hand or machine (e.g. by machine  30 ). The cable(s)  14  are preferably placed into the bottom of the void  12 . More than one cable  14  may be placed in the void  12 . By way of example, ten to twelve small cables  14  each of which run to individual residences  40  may be placed in the void  12  together with another main cable  14   a.  Each cable  14  may contain, for example, one-hundred and forty-four fibers. 
         [0026]    A composition  16  is flowed into the void  12  and over the cable(s)  14 . Generally, the composition must be a flowable composition  16  and non-shrinking upon drying. The composition  16  fills a bottom portion of the void  12  and bonds or encases the cable(s)  14 . The composition  16  is preferably a plaster, grout, or mortar substance. 
         [0027]    For flowing and encasing it is currently preferable to flow a composition  16  in the form of a grout into the void  12  and over the cable(s)  14 . To apply, the operator will ensure the duct  44  is held down into the void  12 . Next, the grout is pumped of poured into the void  12  using, for example, a traditional grouting machine  42  having a pump  43  so that it will flow through the duct  44  and into the void  12 . Preferably the operator will not fill the void  12  with the composition  16  up to the top level of the “covering surface”  10 . 
         [0028]    In describing the composition  16 , by referring to it as “flowing” or “flowable”, this means the composition  16  is viscid (i.e. has a sticky and fluid consistency) yet having a viscosity that does not prevent it from flowing into the void  12  on top of, around and under (i.e. surrounding) the cable(s)  14 . The composition  16  flows under the cable(s)  14  and the cable(s)  14  could even experience some rise as the composition  16  flows around that cable(s)  14  depending upon specific gravity of the cable(s)  14  relative to the composition  16 . Due to the flowability, no air-bubbles or spaces are created in the filled portion of the void  12  below the top surface  17  of the composition  16 . 
         [0029]    In describing the composition  16 , by referring to it as “non-shrinking”, this means the composition  16  is non-compressible, non-expandable, with no contraction. By way of example, the composition  16  should shrink less than one percent upon drying at ambient temperatures. As the composition  16  dries, no air-bubbles or spaces are created in the filled portion of the void  12  below the top surface  17  of the composition  16 . There is no requirement to tamp the composition  16 . 
         [0030]    The composition  16  undergoes rigidification or solidification upon drying or setting. Upon drying, the cable(s)  14  are encased within the composition  16  within the void  12 . 
         [0031]    The composition  16  should be fast drying. The composition  16  should begin to rigidify within the first hour allowing the topping material  20  to be applied within approximately three to twelve hours after the composition  16  has been pumped or poured into the void  12 . 
         [0032]    The dried, rigidified composition  16  is impermeable meaning its hydraulic permeability is less than 0.0000001 cm/s. It has been discovered that groundwater does not negatively affect the integrity of the composition once it is rigidified within the void  12 . 
         [0033]    The currently preferred composition  16  is a grout  16   a  sold under the name SUPERGROUT, but other sufficiently flowable, non-shrinking materials may be implemented into the respective embodiment(s) of the technology discussed herein. SUPERGROUT is commercially available via the owner of domain name “supergroutproducts.com” or from MTsupergrout.com of Saginaw, Mich. In preparation, the grout  16   a  should be fluid when mixed with water. Blend, for example, nineteen liters (five gallons) of potable water per seventy pound bag of SUPERGROUT. The grout  16   a  sets in four hours, and sets as a rigid body. Such grout  16   a  may be topped off with a topping material  20  within one hour of pumping or pouring. 
         [0034]    The composition  16  and the remaining top portion of the void  12  should be filled with a topping material  20  (e.g. blacktop) to cover and seal the composition  16  and the void  12 . The topping material  20  preferably adheres to the composition  16 . Preferably the topping material  20  is aesthetically invisible to the untrained eye. 
         [0035]    It may be preferable to add or blend aggregate into the topping material  20  prior to its application. One having ordinary skill in the art knows how to apply such a topping material  20  which may, for example, be blacktop, asphalt or bitumen heated to 177° centigrade (350° Fahrenheit), and then applied or flowed into the remainder portion of the void  12 . 
         [0036]    A currently preferred topping material  20  (blacktop or asphalt) is a mastic repair material commercially available from (with specifications as provided by) Deery American Corporation, such as that, for example, sold under the brand name DEERY LEVEL &amp; GO repair mastic or the like. Then, aggregate may be mixed in prior to application. 
         [0037]    An operator having ordinary skill in the art may desire to cut a bend or curve when cutting a void  12 . The operator may for example achieve cornering with a 12.2 meter (forty ft.) bending radius, or may make two cuts intersecting at ninety degrees, for example, to form a corner. 
         [0038]    The various embodiments disclosed may be used with dirt roads or a soil surface as the technology is not necessarily limited to use on asphalt or other hard road surfaces. 
         [0039]    After construction is completed and in the event that future road repairs or the like are needed, the applicable surface may be worked, planed, milled and/or removed without damage to the integrity of the cable(s)  14  and normally without damage to the integrity of the rigidified composition  16 .