Abstract:
A drilling apparatus for drilling from inside a conduit having at least one service entrance is described. The drilling apparatus comprises a robot; an elongated flexible appliance having a first end and a second end, the elongated flexible appliance connected to the robot; a rotatable drill head connected to the second end of the elongated flexible appliance; the elongated flexible appliance driven by the robot to extend the rotatable drill head inside the service entrance by at least 8 cm and to retract the rotatable drill head out of the at least one service entrance. The apparatus further comprises means to bend the elongated flexible appliance to orient the drill head connected thereto perpendicular to a longitudinal axis of the conduit.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a drilling apparatus for drilling holes from inside a conduit or pipe perpendicular to the longitudinal axis of the conduit or pipe and more specifically for drilling plugged service entrances in an underground water conduit after the underground conduit was rehabilitated with an internal lining. 
       BACKGROUND OF THE INVENTION 
       [0002]    For many years now, technologies have been developed and used to rehabilitate damaged water and sewage conduits. The various technologies basically consist of re-lining the inside walls of existing underground conduits to rehabilitate the underground conduits. 
         [0003]    The service entrances of the existing conduit are initially plugged with a water plug carrying a position marker with a plug setting robot controlled by an operator looking through a video camera connected to the plug setting robot. Thereafter the existing conduit is re-lined internally with a flexible tubular liner impregnated with a curable resin which is cured in place with recirculating heated water after insertion in the underground conduit. Once the resin is cured and the re-lining of the existing conduit is done, the water plug can be located with a detection and drilling robot using the position marker of the water plug. Once the center of the water plug is located, the water plug is drilled out using a drill mounted on the robot which is operated by the operator. 
         [0004]    The drill mounted on the robot typically consists of a main housing attached to the front portion of the robot that includes a power unit and an actuator for controlling a drilling head positioned at the front of the main housing. The drilling head includes a drill bit extending perpendicular to the drilling head and to the longitudinal axis of the underground conduit. The drilling head is rotatable about the longitudinal axis and also movable back and forth along the same axis such that the operator is able to precisely align the drill bit with the position marker of the water plug blocking the service entrances that may be located in any position around the circumference of the underground conduit. The drilling head is also movable along an axis perpendicular to the main housing such that when the drill bit is properly aligned with the service entrances, the rotating drill bit is actuated to move against the water plug and drill it out by moving the drilling head along that perpendicular axis. The drill head is then retracted thereby opening the previously plugged service entrance. 
         [0005]    Problems may arise when during the re-lining process, the curable resin of the tubular liner seeps into the service entrance, cures inside the services entrance deeper than required such that the standard drill bit is not long enough to remove the cured resin and the services entrance remains blocked or partially clogged by cured resin. The length of the drill bit adapted to be mounted onto a drilling head as previously described is limited by the space available inside the underground conduit and it is not possible to install a longer drill bit onto the drilling head to remove resin cured deep inside the service entrance. The depth of insertion of the drill bit inside the service entrance is limited by the maximum extension of the drilling head along the perpendicular axis previously described. 
         [0006]    Thus, when resin has seeped deep into the service entrance and the standard drilling system is unable to drill deep enough inside the service entrance, the service entrance remains plugged or partially plugged by the cured resin and the fluid connection cannot be re-established leaving the residence or business to which that particular service entrance is connected without water supply or with limited flow of water which is obviously unacceptable. The only solution is to dig up the ground to reach and replace that particular service entrance at great cost. 
         [0007]    Therefore, there is a need for a drilling apparatus adapted to extend deeper and farther inside a plugged service entrance than prior art drilling apparatus. 
       SUMMARY OF THE INVENTION 
       [0008]    It is an object of the present invention to ameliorate at least some of the inconveniences present in the prior art. 
         [0009]    In a first aspect, the present invention seeks to provide a drilling apparatus for drilling from inside a conduit having at least one service entrance, the apparatus comprising a robot; an elongated flexible appliance having a first end and a second end, the elongated flexible appliance connected to the robot; a rotatable drill head connected to the second end of the elongated flexible appliance; the elongated flexible appliance driven by the robot to extend the rotatable drill head inside the at least one service entrance by at least 8 cm and to retract the rotatable drill head out of the at least one service entrance. The apparatus further comprises means to bend the elongated flexible appliance to orient the drill head connected thereto perpendicular to a longitudinal axis of the conduit. 
         [0010]    In one embodiment, the elongated flexible appliance is a flexible shaft connected at its first end to a motor adapted to impart a rotational motion to the flexible shaft and to the rotatable drill head connected to its second end. the robot further comprises a main body and a tooling head, the tooling head adapted to extend in and out of the main body of the robot, the motor is connected to tooling head of the robot, the extension of the tooling head in and out of the main body of the robot driving the rotatable drill head inside and out of the at least one service entrance. 
         [0011]    In one specific aspect of the invention, the flexible shaft is supported inside a hollow tube. In one embodiment, the flexible shaft and the supporting hollow tube move together to drive the rotatable drill head inside and out of the at least one service entrance. In another embodiment, the flexible shaft slides inside the supporting hollow tube to drive the rotatable drill head inside and out of the at least one service entrance. 
         [0012]    In another aspect of the invention, the drilling apparatus includes a driving wheel mounted on the robot and engaging a portion of the elongated flexible appliance to impart motion to the elongated flexible appliance and to rotatable drill head connected thereto. 
         [0013]    In another aspect of the invention, the drilling apparatus further comprises a series of guiding wheels which together with the driving wheel form a driving path for the elongated flexible appliance and the rotatable drill head connected thereto. 
         [0014]    In one specific aspect of the invention, the elongated flexible appliance is connected to a motor which is separate from the robot. 
         [0015]    In a further aspect, the elongated flexible appliance is connected to air or water pressure system adapted to impart a rotational motion to the rotatable drill head and the elongated flexible appliance is a pressure hose. 
         [0016]    In another aspect of the invention, the drill head is connected to the second end of the pressure hose and includes a series of internal passageways that impart rotational motion to the drill head when pressurized fluid passes through the passageways. 
         [0017]    Embodiments of the present invention each have at least one of the above-mentioned objects and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present invention that have resulted from attempting to attain the above-mentioned objects may not satisfy these objects and/or may satisfy other objects not specifically recited herein. 
         [0018]    Additional and/or alternative features, aspects, and advantages of embodiments of the present invention will become apparent from the following description, the accompanying drawings, and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    For a better understanding of the present invention, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where: 
           [0020]      FIG. 1  is an exploded perspective view of a drilling apparatus in accordance with a first embodiment of the invention; 
           [0021]      FIG. 1A  is a partial perspective view of the drilling portion of the drilling apparatus of  FIG. 1  showing the drilling portion partially extended; 
           [0022]      FIG. 2  is a schematic side elevational view of a drilling apparatus in accordance with a second embodiment of the invention; 
           [0023]      FIG. 2A  is a partial side elevational view of the drilling portion of the drilling apparatus of  FIG. 2  showing the drilling portion partially extended; 
           [0024]      FIG. 3  is a schematic side elevational view of a drilling apparatus in accordance with a third embodiment of the invention; 
           [0025]      FIG. 3A  is a partial side elevational view of the drilling portion of the drilling apparatus of  FIG. 3  showing the drilling portion partially extended; 
           [0026]      FIG. 4  is a schematic side elevational view of a drilling apparatus in accordance with a fourth embodiment of the invention; 
           [0027]      FIG. 4A  is a partial side elevational view of the drilling portion of the drilling apparatus of  FIG. 4  showing the drilling portion partially extended; 
           [0028]      FIG. 5  is a side elevational view of a drill head shown in  FIG. 4  in isolation; 
           [0029]      FIG. 5A  is a cut-away view of the drill head shown in  FIG. 5  taken along the axis of rotation  115 ; and 
           [0030]      FIG. 5B  is a top plan view of the drill head shown in  FIG. 5  with internal passageways shown in dotted lines. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    With reference to  FIG. 1 , there is shown a drilling apparatus  10  in accordance with a first embodiment of the invention. The drilling apparatus  10  comprises an electric motor  12  housed in a rigid casing  14 . The electric motor  12  includes a rotating shaft  32  which is connected to a first end of a flexible shaft  50  ( FIG. 1A ) supported inside a first rigid hollow tube  34 ; the second end of the flexible shaft  50  being connected to a drill head  36 . The first rigid hollow tube  34  is slidably inserted into a second rigid hollow tube  35  and the point of insertion of the first and second rigid hollow tubes  34  and  35  is supported by a first support member  52 . The end of the second rigid hollow tube  35  is supported by a second support member  58 . The end of the first rigid hollow tube  34  includes a protruding pin  54  which is inserted into a guiding groove  56  of the second rigid hollow tube  35 . The protruding pin  54  prevents the first rigid hollow tube  34  from rotating when the flexible shaft  50  is spinning and also acts as a stopper against the support members  54  and  58  to prevent the first rigid hollow tube  34  from exiting the second rigid hollow tube  35  at one end and from going too far at the other end. 
         [0032]    The casing  14  of the electric motor  12  and the rigid hollow tubes  34  and  35  are mounted and supported onto a platform  38  comprising a pair of sliding pads  37 ,  39  adapted for sliding inside an underground conduit. As illustrated in  FIG. 1 , the front end  40  of rigid hollow tube  35  is bent such that the drill head  36  is perpendicular to the sliding pads  37 ,  39  and therefore perpendicular to the longitudinal axis of the underground conduit in order to be aimed at the wall of the underground conduit for drilling. The bend  41  of the rigid hollow tube  35  has the largest possible radius in order for the flexible shaft  50  to rotate inside the rigid hollow tube  35  with minimal friction. 
         [0033]    The casing  14  is connected to a robot  24  through a pair of mounting brackets  16  each connected to a universal joint  18  itself connected to a second bracket  20  adapted for mounting to a tooling head  22  located at the front end of the robot  24 . The tooling head  22  is slidably mounted inside a guiding track  26  of a rotating bracket  28 , itself mounted onto a movable arm  30  of the robot  24 . The robot  24  is also mounted and supported onto a platform  44  comprising a pair of sliding pads  45  adapted for sliding inside an underground conduit. Platform  44  and platform  38  are connected together via a tension cable  46  of a predetermined length. 
         [0034]    In operation, the electric motor  12  is activated to spin the rotating shaft  32  connected to the first end of the flexible shaft  50  thereby spinning the flexible shaft  50  inside a rigid hollow pipe  34  which in turn spins the drill head  36  connected to the second end of the flexible shaft  50 . In order to extend the drill head  36  out of the front end  40  of rigid hollow tube  35  as shown in  FIG. 1A  with arrows ‘b’, the movable arm  30  of the robot  24  is adapted to extend in and out of the main body of the robot  24  as shown by arrows “a” thereby moving the tooling head  22  and the casing  14  of the electric motor  12  in the same direction, The moving electric motor  12  pushes the first rigid hollow tube  34  forward inside the second rigid hollow tube  35  as shown in  FIG. 1A  by the same length as the movable arm  30  extending out of the robot  24  and in so doing extend the spinning drill head  36  out of the front end  40  of rigid hollow tube  35  as shown with arrows ‘b’ by the same length. The drill head  36  is therefore able to drill out the plug plugging the service entrance and extend deep inside the service entrance to drill out any cured resin that may have seeped into the service entrance. 
         [0035]    In operation, an operator is looking through a video camera positioned near the front end  40  of rigid hollow tube  35  and the drill head  36  and is able to visually align the drill head  36  with the center of the plugged service entrance by moving the robot along the longitudinal axis of the underground pipe and then rotating bracket  28  until the drill head  36  is aligned perpendicular to the plugged service entrance as previously described. When the drill head  36  is aligned to the plugged service entrance, the operator activates the electric motor  12  to spin the rotating shaft  32  connected to the first end of a flexible shaft  50  thereby spinning the drill head  36 . The operator then activates the movable arm  30  in order to move the drill head  36  into contact with the plug plugging the service entrance to drill it out. Once the plug is drilled out, the operator continues the activation of the movable arm  30  and the extension of the drill head  36  to move the drill head  36  deeper inside the service entrance by 8 to 15 cm to make sure that the service entrance is fully reopened and no cured resin remains inside to impede the flow of water. The drill head  36  and flexible shaft  50  are then retracted from the service entrance by retracting the movable arm  30  back to its starting position before moving the drilling apparatus  10  towards another plugged service entrance to be drilled out. 
         [0036]    With reference to  FIG. 2 , there is shown a schematic illustration of a drilling apparatus  60  in accordance with a second embodiment of the invention. The drilling apparatus  60  includes a robot  24  having a movable arm  30  and a tooling head  22  to which is mounted an electric motor  12  similar to the configuration described with reference to drilling apparatus  10  shown in  FIG. 1 . The electric motor  12  also includes a rotating shaft  32  which is connected to the first end of a flexible shaft  50 ; the second end of the flexible shaft  50  being connected to a drill head  36 . In this particular embodiment, the flexible shaft  50  is positioned inside a semi rigid reinforced hollow tube  62  extending from the electric motor  12  to the drill head  36  which provides support for the flexible shaft  50 . The semi rigid reinforced hollow tube  62  is fixedly connected to a mandrel  64  of the electric motor  12  at a first end  65  and is supported and guided at a second end by a series of guiding wheels  67  and  68  mounted onto a support bracket  70  in a configuration that bends the semi rigid reinforced hollow tube  62  by approximately 90 degrees such that the drill head  36  is perpendicular to the longitudinal axis of the underground conduit in order to be aimed at the wall of the underground conduit for drilling. The robot  24  and the support bracket  70  are both mounted onto a common platform  72  adapted for sliding within the underground conduit while the electric motor  12  is free to move back and forth relative to platform  72  as illustrated by arrow “a”. 
         [0037]    In operation, the electric motor  12  is activated to spin the rotating shaft  32  connected to the first end of the flexible shaft  50  thereby spinning the flexible shaft  50  inside the semi rigid reinforced hollow tube  62  which in turn spins the drill head  36  connected to the second end of the flexible shaft  50 . In order to extend the drill head  36  as shown in  FIG. 2A  with arrows ‘b’, the movable arm  30  of the robot  24  is adapted to extend in and out of the main body of the robot  24  as shown by arrows “a” thereby moving the tooling head  22  and the electric motor  12  in the same direction. The moving electric motor  12  pushes the entire assembly including the semi rigid reinforced hollow tube  62  and the flexible shaft  50  through the series of guiding wheels  67  and  68  as illustrated by arrow ‘b’ by the same length as the movable arm  30  extending out of the robot  24  and in so doing pushes the spinning drill head  36  into contact with the plug plugging the service entrance to drill it out and continue deep inside the service entrance to drill out any cured resin that may have seeped into the service entrance. 
         [0038]    As previously described with reference to  FIGS. 1 and 1A , in operation, an operator is looking through a video camera positioned near the support bracket  70  and the drill head  36  and is able to visually align the drill head  36  with the center of the plugged service entrance by moving the robot  24  along the longitudinal axis of the underground pipe until the drill head  36  is aligned perpendicular to the plugged service entrance. When the drill head  36  is aligned with the plugged service entrance, the operator activates the electric motor  12  to spin the rotating shaft  32  connected to the first end of a flexible shaft  50  thereby spinning the drill head  36 . The operator then activates the movable arm  30  in order to move the drill head  36  into contact with the plug plugging the service entrance to drill it out. Once the plug is drilled out, the operator continues the activation of the movable arm  30  in order to extend the assembly including the semi rigid reinforced hollow tube  62  and the flexible shaft  50  to move the drill head  36  deeper inside the service entrance by 8 to 15 cm to make sure that the service entrance is fully reopened and no cured resin remains inside to impede the flow of water. The assembly including the semi rigid reinforced hollow tube  62 , the flexible shaft  50  and the drill head  36  are then retracted from the service entrance by retracting the movable arm  30  back to its starting position before moving the drilling apparatus  60  towards another plugged service entrance to be drilled out. 
         [0039]    With reference to  FIG. 3 , there is shown a schematic illustration of a drilling apparatus  80  in accordance with a third embodiment of the invention. The drilling apparatus  80  includes a robot  24  having a tooling head  22  to which is mounted an electric driving wheel  82  powered by the robot electric system. In front of the driving wheel  82  is a set of three guiding wheels  83 ,  84  and  85  which together with the driving wheel  82  form a driving path for an assembly comprising a semi rigid reinforced hollow tube  62 , a flexible shaft  50  and a drill head  36  similar to the assembly previously described with reference to  FIG. 2 . Behind the robot  24  is an electric motor  12  also including a rotating shaft  32  which is connected to the first end  86  of the flexible shaft  50 ; the second end  87  of the flexible shaft  50  being connected to the drill head  36 . The flexible shaft  50  is positioned inside the semi rigid reinforced hollow tube  62  extending from the electric motor  12  to the drill head  36  which provides support for the flexible shaft  50 . The semi rigid reinforced hollow tube  62  is fixedly connected to a mandrel  64  of the electric motor  12  at the first end  86  and is supported and guided at its second end  87  by the driving path formed by driving wheel  82  and the three guiding wheels  83 ,  84  and  85  in a configuration that bends the semi rigid reinforced hollow tube  62  by approximately 90 degrees such that the drill head  36  is perpendicular to the longitudinal axis of the underground conduit in order to be aimed at the wall of the underground conduit for drilling. The robot  24  is mounted onto a platform  88  adapted for sliding within the underground conduit while the electric motor  12  is supported by an independent platform  90  also adapted for sliding within the underground conduit but free to move back and forth relative to platform  88  as illustrated by arrow “a”. 
         [0040]    In operation, the electric motor  12  is activated to spin the rotating shaft  32  connected to the first end  86  of the flexible shaft  50  thereby spinning the flexible shaft  50  inside the semi rigid reinforced hollow tube  62  which in turn spins the drill head  36  connected to the second end  87  of the flexible shaft  50 . In order to extend the drill head  36  as shown in  FIG. 3A  with arrows ‘b’, the driving wheel  82 , which engages the semi rigid reinforced hollow tube  62 , is activated to rotate slowly in the counter clockwise direction thereby moving the assembly including the semi rigid reinforced hollow tube  62 , the flexible shaft  50  and the drill head  36  upward and at the same time pulling on the electric motor  12  attached thereto, and in so doing pushes the spinning drill head  36  into contact with the plug plugging the service entrance to drill it out and continue deep inside the service entrance to drill out any cured resin that may have seeped into the service entrance. 
         [0041]    As previously described with reference to  FIGS. 1 and 2 , in operation, an operator is looking through a video camera positioned near the driving wheel  82  and the drill head  36  and is able to visually align the drill head  36  with the center of the plugged service entrance by moving the robot  24  along the longitudinal axis of the underground pipe until the drill head  36  is aligned perpendicular to the plugged service entrance. When the drill head  36  is aligned with the plugged service entrance, the operator activates the electric motor  12  to spin the rotating shaft  32  connected to the first end  86  of a flexible shaft  50  thereby spinning the drill head  36 . The operator then activates the driving wheel  82  in the counter clockwise direction in order to move the drill head  36  into contact with the plug plugging the service entrance to drill it out. Once the plug is drilled out, the operator continues the activation of the driving wheel  82  in order to extend the assembly including the semi rigid reinforced hollow tube  62  and the flexible shaft  50  to move the drill head  36  deeper inside the service entrance by 8 to 15 cm to make sure that the service entrance is fully reopened and no cured resin remains inside to impede the flow of water. The assembly including the semi rigid reinforced hollow tube  62 , the flexible shaft  50  and the drill head  36  is then retracted from the service entrance by activating the driving wheel  82  in the clockwise direction which moves the assembly back to its starting position and pushes the electric motor  12  back to its starting position. The drilling apparatus  80  may then be moved towards another plugged service entrance to be drilled out. 
         [0042]    With reference to  FIG. 4 , there is shown a schematic illustration of a drilling apparatus  95  in accordance with a fourth embodiment of the invention. The drilling apparatus  95  includes a robot  24  having a tooling head  22  to which is mounted an electric driving wheel  82  powered by the robot electric system identical to the one shown and described with reference to  FIG. 3 . In front of the driving wheel  82  is a set of three guiding wheels  83 ,  84  and  85  which together with the driving wheel  82  form a driving path for a drilling assembly  97 . The drilling assembly  97  consists of a reinforced flexible pressure hose  98  having a drill head  99  connected to its outermost end  101  which is driven by air or water pressure supplied through the pressure hose  98 . The end  102  is connected to an air or water pressure system powered by a motor connected to an air or a hydraulic pump located outside the underground conduit or pipe being rehabilitated. The robot  24  is mounted onto a platform  88  adapted for sliding within the underground conduit and the flexible pressure hose  98  passes underneath the robot  24 . 
         [0043]    The drilling assembly  97  is supported and guided at its outermost end  101  by the driving path formed by driving wheel  82  and the three guiding wheels  83 ,  84  and  85  in a configuration that bends the flexible pressure hose  98  by approximately  90  degrees such that the drill head  99  is perpendicular to the longitudinal axis of the underground conduit in order to be aimed at the wall of the underground conduit for drilling. 
         [0044]    In operation, an air or water pump (not shown) is activated and pressurised fluid is fed into the flexible pressure hose  98  which in turn spins the drill head  99  connected to its outermost end  101 . In order to extend the drill head  99  as shown in  FIG. 4A  with arrows ‘b’, the driving wheel  82 , which engages the pressure hose  98 , is activated to rotate slowly in the counter clockwise direction thereby moving the drilling assembly  97  and therefore the drill head  99  upward and in so doing pushes the spinning drill head  99  into contact with the plug plugging the service entrance to drill it out and continue deep inside the service entrance to drill out any cured resin that may have seeped into the service entrance. 
         [0045]    As previously described with reference to  FIGS. 1 to 3 , in operation, an operator is looking through a video camera positioned near the driving wheel  82  and the drill head  99  and is able to visually align the drill head  99  with the center of the plugged service entrance by moving the robot  24  along the longitudinal axis of the underground pipe until the drill head  99  is aligned perpendicular to the plugged service entrance. When the drill head  99  is aligned with the plugged service entrance, the operator activates the air or water pump (not shown) to spin the drill head  99 . The operator then activates the driving wheel  82  in the counter clockwise direction in order to move the drill head  99  into contact with the plug plugging the service entrance to drill it out. Once the plug is drilled out, the operator continues the activation of the driving wheel  82  in order to extend the drilling assembly  97  to move the drill head  99  deeper inside the service entrance by 8 to 15 cm to make sure that the service entrance is fully reopened and no cured resin remains inside to impede the flow of water. The drilling assembly  97  is then retracted from the service entrance by activating the driving wheel  82  in the clockwise direction which moves the drilling assembly  97  back to its starting position. The drilling apparatus  95  may then be moved towards another plugged service entrance to be drilled out. 
         [0046]    With reference to  FIG. 5 ,  5 A and  5 B, the drilling head  99  comprises a shaft portion  105  and a head portion  106 . The head portion  106  includes on its outer surface a series of teeth  107  adapted for drilling. The shaft portion  105  is connected to the outermost end  101  of the flexible pressure hose  98  via a bearing  108  held in place by a shoulder  109  within the flexible pressure hose  98 . The shaft portion  105  of the drill head  99  includes a central passageway  110  and the head portion  106  includes a series of angled passageways  112 ,  114  connected to the central passageway  130 . As illustrated in  FIG. 5B , the angled passageways  112  and  114  are curvilinear and are at an angle relative to the axis of rotation  115  of the drill head  99 . When pressurised fluid from the flexible pressure hose  98  enters the central passageway  110 , it is directed into the angled passageways  112 ,  114  as illustrated by arrows “c” which has the effect of rotating the drill head  99  due to the angle of the passageways relative to the axis of rotation  115  of the drill head  99 . 
         [0047]    Modifications and improvements to the above-described embodiments of the present invention may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting. The scope of the present invention is therefore intended to be limited solely by the scope of the appended claims.