This application is a continuation-in-part of U.S. patent application Ser. No. 09/277,467 filed Mar. 26, 1999 now U.S. Pat. No. 6,318,952 patented Nov. 20, 2001, the disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to trench digging and pipe laying equipment, and more particularly to an adjustable coupling connector for use in attaching equipment to an excavator, wherein the equipment includes a pipe laying tool and a compaction wheel. 
     2. Brief Description of the Prior Art 
     The process of laying sections of pipe for an underground pipe line involves first digging a trench to the required depth with a shovel attached to an excavator. The shovel is then removed from the excavator and a pipe laying tool is attached to the excavator for lowering the pipe into the trench. The pipe laying tool is then removed from the excavator and replaced with a shovel for use in depositing the required filler over the pipe. The shovel is then removed and a compaction wheel is attached for compacting the filler. Various methods of attaching the shovel, compaction wheel and pipe laying tool to the excavator are used. At the present time there is no standard connector for attaching tools to an excavator. If the excavator can accommodate the compaction wheel but not the pipe laying tool, the pipe may be secured to an end of an arm or boom of the excavator with chains and chokers. A disadvantage of this method is that it is necessary to place a worker in the trench to guide the newly lowered section of pipe into contact with a previously installed section. The worker must also disengage the chains, etc. from the pipe. The task of manipulating the pipe in the trench is not without some hazard, due in part to the weight of the pipe and excavator arm. In deep trenches, the additional hazard of possible collapse of the trench walls must be carefully guarded against for the safety of the trench worker. In cases where there is danger of wall collapse, shoring is often put up in place to support the soil. The shoring must then be removed and reinstalled for the process of laying the next section or sections of pipe, etc. 
     U.S. Pat. No. 5,232,502 by Recker describes an apparatus designed to lay pipe with an excavator without the need for a worker in the trench. A horizontally positioned arm  78  is suspended from the working end of an excavator boom assembly, attached with a rotary coupler  76  (FIG.  2  and col. 3, lines 3-32). In order to avoid the need for a worker in the trench to apply pipe sealant, a sealant is forced through the rotary coupler and sprayed from the end of the horizontal arm. The apparatus as described has some disadvantages and is not in common use. The rotary couple with conduit is not a standard quick coupler, and requires special modification of the excavator. Connecting the horizontal arm  78  and conduit requires a second worker, or alternatively the excavator operator has to leave the cab to manually perform the operation. Positioning the arm  78  and support beam  80  in the process of connecting the tool to the excavator arm assembly is also a problem due to the weight of the tool, and the fact that without other support, the tool could only lay on the ground, 90 degrees disoriented, requiring an operator, probably with additional equipment to lift it into position for connecting to the excavator coupling device  70 . In addition, the rotary connection  76  is not durable enough to withstand repeated use, or rigid enough to allow undesired rotation of a pipe placed on the arm  78 . For example, a typical eight foot section of 54 inch diameter concrete pipe weighs about 1,370 pounds per foot, or a total of 10,960 pounds. A much more rigid and strong connection is required for practical use. 
     It is apparent that an improved tool and method of laying pipe is needed that keeps workers out of the pipe trench, and that is robust and can be used with a standard excavator arm quick coupling device. It is also apparent that a coupling device is needed that can accommodate a range of different excavator coupling apparatus. 
     SUMMARY 
     It is therefore an object of the present invention to provide a connector that can be adjusted for a range of sizes of excavator coupling apparatus. 
     It is an object of the present invention to provide a tool for use in lowering a section of pipe into a trench that avoids the use of chains and chokers that must be removed by a trench worker. 
     It is another object of the present invention to provide a tool for laying pipe that is rugged in construction and that can be attached to the working end of an excavator boom assembly by an excavator operator without leaving the excavator cab. 
     It is a further object of the present invention to provide a tool that facilitates the joining of pipe sections without the need for a trench worker. 
     Briefly, a preferred embodiment of the present invention includes an adjustable connector for accommodating a range of mating excavator couplers. The adjustable connector includes two parallel bars to which the excavator coupler clamps. One of the bars is fixed in position to risers extending from a connector base. Each end of the other bar is attached to a point off center of a circular plate so that as the plate is rotated, the bar moves laterally relative to the bar axis. The plates are rotatably positioned in holes in the risers, and captivating side plates are welded to the risers for covering a portion of each plate, securing the plates from movement parallel to its axis but allowing the plate to rotate. Holes in the circular plates and side plates are provided, and a bolt is placed through each of the side plates and circular plates for securing each circular plate in a fixed position. 
     An advantage of the adjustable connector apparatus of the present invention is that it can accommodate a range of excavator coupler sizes. 
     An advantage of the tool of the present invention is that it allows a pipe to be positioned in a trench with improved accuracy. 
     A further advantage of the tool of the present invention is that it allows a pipe supported by the tool to be joined to another pipe in a trench without the need for a trench worker. 
     A still further advantage of the present invention is that it reduces worker injury by avoiding the need for a worker in the trench during the pipe laying operation. 
     Another advantage of the present invention is that it provides a pipe laying tool that is self supporting, and does not require an excavator operator to leave the excavator cab to connect the tool. 
    
    
     IN THE DRAWING 
     FIG. 1 is a perspective view of the pipe laying tool of the present invention; 
     FIG. 2 shows an absorptive bumper mounted to a riser; 
     FIG. 3 illustrates the use of the tool to place a pipe in the trench; 
     FIG. 4 illustrates the use of the tool in combination with an excavator and positioning device for laying a section of pipe in a trench; 
     FIG. 5 is a perspective view of a preferred construction of the coupling connector of FIG. 1 indicating enhanced side support for the connector loops; 
     FIG. 6 is a perspective view of an adjustable quick coupling connector; 
     FIG. 7 is a top planar view of the adjustable connector of FIG. 6; 
     FIG. 8 a  is a planar view of the riser plates of the adjustable connector of FIG. 6; 
     FIG. 8 b  is a planar view of the circular end plates of FIG. 6; 
     FIG. 8 c  is a planar view of the side plates of FIG. 6; and 
     FIG. 9 shows a connector in use with a compaction wheel attached to an excavator. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The preferred embodiment of the pipe laying tool  10  of the present invention is shown in the perspective views of FIGS. 1 and 2. Referring to FIG. 1, the tool  10  has a proximal end  12 , to which is attached a horizontal tool arm  14  extending horizontally in operation to a distal end  16 . The arm  14  is connected at the proximal end of the tool to a vertical riser  18 , in turn attached to a coupling assembly  20 . A lateral support  22  allows the tool  10  to stand unsupported, facilitating the process of connecting the tool to a working end of an excavator arm. 
     As shown in FIG. 1, the arm  14  includes a length  24  of 4×4 inch×0.5 inch rectangular tubing about 6 feet long. The length can be longer or shorter depending on the length of pipe to be installed. Optionally, as an alternative embodiment, a pipe extension  26  is included in the tool  10 . The extension has a reduced size section  28  for insertion in the hollow center  30  of tube  24  for use in accommodating somewhat longer pipe. A 1.25×2.0 inch bar  32  is welded to the bottom of the tube  24  for increased strength, and extends over the majority of the arm  14  length to the lateral support  22  including a stabilization bar  34 , constructed from a 30 inch length of 2.0×2.0×0.25 inch wall tubing. The riser  18  is similarly constructed from a 28 inch length of 4×4×0.5 inch tubing  36 , braced with a 34 inch long piece of 0.75×5.0 inch flat bar  28 . 
     A support bar  40  of 4×4×0.5 inch tubing by 51.5 inches long is welded to the top end of riser tube  36 , and provides strength to the coupling assembly  20 . A 1.5 inch thick support plate  42 , measuring about 24 inches wide by 27 inches long is welded to the tube  40 . The coupling assembly  20  includes a coupling connector  44  with a connector plate  46  secured to support plate  42  with bolts  48  or by welding, and supports  50  for positioning coupling bars  52  and  54 . 
     The various elements  24 ,  34 ,  36 ,  40 , and  42  described above are welded together along with triangular support members  56 ,  58 ,  60 ,  62  for strength. Similarly, triangular support members  64 ,  66 ,  68  and  70 , shown in FIG. 3, and corresponding supports on the opposite side of tube  40  are welded between plate  42  and tube  40 , and between tube  40  and tube  36  as shown in FIGS. 1,  2  and  3 . A laser receiver  124  and pole  126  are shown mounted to plate support  42 . The function of this apparatus will be fully explained in the following description in reference to FIG.  4 . 
     In order to minimize the probability of damaging the pipe while applying horizontally directed force to engage one section of pipe with another, an absorptive bumper  72  is attached to the riser tube  36  facing the distal end  16 . The bumper apparatus is illustrated in section A of FIG.  2 . The bumper  72  preferably includes a 2×4 inch board  74  attached to riser tube  36  with bolts  76 , countersunk into the board  74  as shown in FIG.  2 . In order to further cushion the end of the pipe, a rubber sheet  78  is placed over the board  74  as shown in FIG.  2 . The sheet  78  is bolted to two plates  80 ,  82  welded with one on each side of riser tube  36 . The bumper assembly, including plates  80  and  82  are part of the tool of FIG. 1 but not shown in that figure for the purpose of clarity of illustration. 
     Alternative construction methods and materials will be apparent to those skilled in the art, and these are included in the spirit of the present invention. For example, the rectangular tubes shown in FIGS. 1 and 2 could be constructed from round tubing or I-beam shaped material. The supports to be described could alternatively be tubular lengths of material, or even omitted if enough strength is otherwise designed into the structure. The coupling assembly  20  could include a single piece platform welded to the riser  18 . 
     Referring now to FIG. 3, the tool  10  is shown with the connector  44  engaged with a corresponding mating connector  84  attached to the working end  86  of excavator  88  arm assembly  90 . In operation, the tool  10  is attached to the working end  86  of excavator  88 . Any time prior to moving a section of pipe such as  92  (dashed lines) into the trench  94  as shown in FIG. 3, a gasket  96  is placed on the pipe spigot end  112 . The excavator  88  is then operated to insert the tool arm  14  inside the length of pipe  92  as it lays outside the trench  94 . FIG. 3 then shows the pipe  92  at position  104 , being lowered down into the trench  94 . Lowering and positioning of the pipe  92  continues until the pipe  92  is in alignment with a previously laid section of pipe, such as  106  on the bottom  108  of the trench  94 . The positioning then includes joining the pipe section  92  to the previously laid section of pipe  106 . The bumper  72  provides a cushioned contact against the end  98  of pipe  92  as the end  112  of pipe  92  is inserted into the adjoining end  114  of pipe  106 . 
     Referring to FIG. 4, according to the preferred embodiment of the method and apparatus of the present invention, the tool  10  is accompanied by a laser positioning apparatus  116 . An example of such an apparatus is a device called a Depth Master, manufactured by a company known as Laser Alignment. The apparatus includes a laser transmitter  118  positioned a distance D 1  above surface  120  and adjusted to transmit a reference laser beam  122  at the required slope B. A laser receiver  124  is slideably attached to a pole  126  shown attached to the tool  10  plate  42 . 
     The transmitter  118  has a light  128  that turns on when the beam  122  is intercepted by the receiver  124  detector  130 . If the detector  130  is below the line  122 , a light  134  turns on, and if the detector is above the beam  122 , light  136  turns on. In operation, the transmitter  118  is adjusted so that the beam  122  is at an angle B equal to the desired slope of the pipe and trench bottom  108 . FIG. 4 shows a preferred method of adjusting the receiver  124  position on the pole  126  so that when pipe  92  arrives at the proper depth, the light  128  goes on. This is done by lowering a section of pipe  100  into the trench  94  until the pipe  100  just contacts the bottom  108 . The receiver  124  is then positioned on the pole  126  so that beam  122  is intercepted by the receiver detector  130 . The excavator and tool are then used to lay pipe as follows: Assume pipe  100  is laid in position as shown and a second pipe section is picked up by the tool  10 . The excavator is backed up with the second pipe so that when it is lowered it will clear pipe  100 . It is then lowered into the trench until the light  128  goes on. The excavator then moves forward with the second pipe, adjusting as required to keep the light  128  on, assuring that the second pipe is in alignment with pipe  100 , and allowing the second pipe to join properly with pipe  100 . In other words, the distance from the beam to the bottom of the trench is a constant, and the depth measurement equipment assures that the pipe is at that depth when the excavator operator attempts to join the two pipe sections together. The transmitter  118  has a second set of lights  140  that gives the operator a visual indication of the vertical alignment of the receiver  124  and therefore pole  126 . As used in the present invention, this vertical alignment indicator  140  indicates to an excavator operator whether or not a pipe being held by the tool  100  is in a horizontal, or near horizontal position since the slope B is generally very small, as required for proper mating with a previously laid section of pipe. 
     Other depth measuring apparatus are also included in the spirit of the present invention. For example, an apparatus using encoders is available. The positioning of the tool arm  14  relative to a reference such as bottom level  108  is determined by the position detection apparatus which includes a processor and monitor for calculating and displaying the position. The calculation is based on signals received from encoders located on the excavator boom assembly to detect the assembly position. The encoders and position monitoring equipment are currently known in the art and applied for positioning shovels mounted on the working end of an excavator arm assembly. The technology of depth detection can be applied to the positioning of a section of pipe as explained above. It is apparent then, that those skilled in the art will know how to apply the technology to measure the depth of the pipe according to the present invention after reading the present disclosure, and a detailed description of the prior art apparatus and how it is used is therefore not included. 
     FIG. 5 is a perspective view of a coupling connector  140  with two rods  142  and  144  forming loops  146  and  148  with the base  150  and side supports  152  and  154 , similar to the structure shown in FIG. 1, etc. except that the supports  50  of FIG. 1 are not interconnected with the added support material  156  and  158  in FIG.  5 . 
     FIG. 6 is a perspective view of an adjustable coupling connector  160 . Parallel first and second side supports  162  and  164  are attached to a first side of a base  166 , preferably by welding, and at a first end  169  support first and second ends  163  and  165  of a first rod  168  above the base  166 . The ends  163  and  165  are preferably welded to the corresponding supports  164  and  162 . The rod  168  with supports  162  and  164  and base  166  form a loop  170 , allowing engagement with a corresponding coupling member of an excavator. An adjustable assembly  172  is positioned near a second end  174  of the supports  162  and  164 , allowing a second rod  176  to be adjustable in position relative to the first rod  168  and thereby allowing accommodation of various excavator coupling apparatus. The second rod  176  is suspended over the base  166  by supports  162  and  164  forming a second loop  178 , and together with rod  168  provide engagement with the coupling apparatus of an excavator. The adjustable assembly  172  includes the second rod  176  attached (preferably welded) at each of first and second rod ends  184  and  186  to first and second circular plates  180  and  182  respectively. The first and second rod ends  184  and  186  are attached to corresponding first and second plates  180  and  182  at a point that is off of the center of each of the first and second plates so as to provide lateral movement i.e., movement relative to rod  168  as the circular plates  180  and  182  are rotated. 
     Circular plates  180  and  182  are mounted in corresponding first and second circular holes  188  and  190  respectively that are formed in support plate apparatus, shown as the support plates  164  and  162 . The sub-assembly including rod  176  and circular plates  180  and  182  is held in position along the direction of the rod axis  192  by axial restraining apparatus illustrated as first side plate apparatus, illustrated as side plates  194 ,  196 , and second side plate apparatus illustrated as side plates  198  and  200 , attached (preferably welded) to the supports  162  and  164 . Side plates  194  and  198  are not visible in the perspective view of FIG. 6, but are shown in the planar top view of FIG.  7 . The circular plates  180  and  182 , and the side plates  194 - 200  all have holes. Holes  222 ,  224 ,  226  and  228  in side plates  196  and  200  are visible in the view of FIG.  6 . The holes in the circular plates are shown in FIG. 8 b.  Because the rod  176  is mounted off of the center of circular plate  180  and  182 , as the plates are rotated the rod  176  moves in an arc, toward or away from rod  168  as well as moving in a vertical direction. In order to adjust the distance between rods  168  and  176 , the circular plates  180  and  182  are rotated. The holes in the circular plates  180  and  182  and the holes in the side plates  194 - 200  are configured/positioned so that the rod  168  to rod  176  spacing can be selected by aligning specific selected holes in plates  180  and  182  with specific holes in side plates  194 - 200 . A bolt is then inserted through the aligned holes in order to secure the position of rod  176 . This operation will be described in reference to FIGS. 8 a-   8   c  for a specific set of parameters as an example. The present invention includes any set of parameters/dimensions, and also includes other constructions for varying the spacing between rods  168  and  176  that will be apparent to those skilled in the art from reading the present disclosure. The bolts for securing the position are not shown in FIG. 6, but are shown in FIG.  7 . 
     FIG. 7 is a planar top view of the adjustable connector  160  of FIG.  6 . FIG. 7 shows the side plates  194 ,  196 ,  198  and  200  fully captivating the circular plates  180  and  182  from movement in the direction of the axis  192  of the rod  176 . Rotational movement of the circular plates  180  and  182  is prevented by rotational restraining apparatus when they are in a desired position with at least one hole in each of the circular plates  180  and  182  lining up with a corresponding hole in each of the plates  194 ,  196 ,  198  and  200 , by insertion of a first bolt  202  and a second bolt  204  through the lined-up holes in the circular plates  180  and  182  with the selected holes in side plates  194 ,  196 ,  198  and  200 . The bolts  202  and  204  are secured by corresponding first and second nut  206  and  208  respectively. Other methods and apparatus for securing the circular plate  180  and  182  will be apparent to those skilled in the art, and these are also included in the spirit of the present invention. Also, other methods and apparatus for adjustably positioning two rods relative to each other will be apparent to those skilled in the art upon reading the present disclosure, and these are also to be included in the spirit of the present invention. 
     Detailed dimensions of a preferred embodiment of a support plate  162  and  164 , circular plates  180  and  182 , and side plates  194 - 200  are shown in the planar view of FIGS. 8 a,    8   b  and  8   c.  In FIG. 8 a,  hole  210  is machined to accept a dimension of the rod  168 . Hole  212  is dimensioned to slideably receive the circular plate such as plates  180  and  182 , and as illustrated plate  214  of FIG. 8 b.    
     In FIG. 8 b,  the circular plate  214  has a hole  215  offset from a pivot axis point which is the center of the plate  214  for acceptance of one end of rod  176  to which it is preferably welded. Holes  216 ,  218  and  220  are dimensioned for passage of a bolt such as bolt  202  or  204 . The locations of holes  216 ,  218  and  220  are designed to place the rod  176  a desired distance from rod  168  when aligned with a corresponding location of a specific one of holes  222 ,  224 ,  226  or  228  in the side plate  230  of FIG. 8 c.  The use of a plurality of holes such as  216 - 220  in the circular plate  214  and a plurality of holes in the side plate  230  allows the holes in the side plate, for example, to be spaced further apart than what would be required if only one hole was used in the circular plate  214  in order to achieve the range of adjustability required. The larger spacing of holes results in a connector with superior strength, which is an important factor in a connector which must handle very heavy loads. With hole  216  of circular plate  214  in alignment with hole  222  of plate  230 , the spacing between rods  168  and  176  is 18 inches. With hole  218  in alignment with hole  224  the spacing is 19 inches. With hole  218  in alignment with hole  226  the spacing is 17½ inches, and with hole  220  aligned with hole  228 , the spacing is 18¾ inches. 
     The connector of FIGS. 6 and 7 can be used with any of various heavy equipment requiring coupling to a tool. In particular, the connector of FIGS. 6-8 can be used as illustrated in FIG. 1 for coupling to a pipe laying tool. FIG. 9 shows the connector  160  providing coupling between an excavator  232  and a compaction wheel  234 . The connector  160  can also connect to a pipe laying tool such as to the support plate  42  of the tool shown in FIG. 1 instead of the compaction wheel  234 . 
     Although the present invention has been described above in terms of a specific embodiment, it is anticipated that alterations and modifications thereof will no doubt become apparent to those skilled in the art. It is therefore intended that the following claims be interpreted as covering all such alterations and modifications as fall within the true spirit and scope of the invention.
An adjustable coupling connector apparatus for accommodating a range of mating excavator couplers. The connector apparatus includes two parallel bars upon which an excavator coupler clamps. One of the bars is fixed in position to risers extending from a connector base. Each end of the other bar is attached to a point off center of a circular plate so that as the plate is rotated, the bar moves laterally relative to the bar axis. The plates are rotatably positioned in holes in the risers, and captivating side plates are welded to the risers for covering a portion of each plate, securing the plates from movement parallel to its axis but allowing the plate to rotate. Holes in the circular plates and side plates are provided, and a bolt is placed through each of the side plates and circular plates for securing each circular plate in a fixed position.