Abstract:
A drilling assembly for drilling holes in concrete structures. The assembly includes a base assembly defining a longitudinal axis and adapted to support at least two concrete structures, for example, on turntables positioned in spaced apart relation along the longitudinal axis. A drilling machine is movably mounted to the base assembly between the turntables for movement along the longitudinal axis, and includes a drill assembly having first and second drill bits each substantially aligned along the longitudinal axis and facing substantially opposite directions. In this manner, the drilling machine includes an in-line, dual drill bit assembly which allows the machine to move along a single horizontal axis for both drilling operations and for traversing between the turntables. Advantageously, the present assembly combines the traverse and drilling axes of the drilling machine into a single horizontal axis, thus eliminating the need to traverse the machine between a pair of turntables along a first horizontal axis and to perform drilling operations along a second horizontal axis.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit under Title, 35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 60/868,587, entitled CORE DRILLING MACHINE, filed on Dec. 5, 2006, the disclosure of which is expressly incorporated by reference herein. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a core drilling machine for drilling holes in concrete structures such as manhole risers, for example, to allow pipes to be attached to the concrete structures. 
   2. Description of the Related Art 
   Concrete structures are often used in municipal water and sewer systems and in other groundwater systems, for example, as manhole risers to which underground pipes are connected. Typically, the concrete structures are cast in the form of concrete boxes or concrete cylinders having a square or round wall, a floor, and an open upper end. After the concrete structure is cast, one or more circular holes are drilled in the wall or walls of the concrete structure to provide an interface to which an underground pipe may be attached via a sealing assembly. Typically, the sealing assembly includes an annular gasket, an expansion band mechanism for sealing the gasket within the hole in the wall of the concrete structure, and an external clamping band for sealing the annular gasket to the outer surface of the pipe. 
   One known machine assembly  10  for drilling holes in concrete structures is shown in  FIG. 1 , and includes a drilling machine  12  generally including frame  14 , a drive unit  16 , such as an electric or hydraulic motor, and a single drill bit  18  rotatably driven by the drive unit  16 . The machine  12  is typically fixed to the floor of a building adjacent a turntable  20  upon which a concrete structure CS is supported. The machine  12  includes a drill bit translation device, such as a hydraulic cylinder  22 , to move the drill bit  18  toward and away from the concrete structure to drill a hole in a wall of the concrete structure. The turntable  20  may be rotated to align different portions of the wall or walls of the concrete structure with the drill bit  18  in order for the machine  12  to drill multiple holes in the concrete structure. Also, the height of drill bit  18  is vertically adjustable with respect to frame  14  of the machine  12  to vary the vertical location at which holes are drilled in the concrete structure. After a desired number of holes are drilled in the concrete structure, the concrete structure is moved off of the turntable  20 , such as by a crane, and another concrete structure is moved on to the turntable to drill holes therein. 
   Thus, the operation of the assembly  10  involves three separate movement axes, including a horizontal drilling axis and a vertical adjustment axis associated with machine  12 , and a vertical rotational axis associated with turntable  20 . 
   Although the assembly shown in  FIG. 1  has proven to be effective, the need to adjust the rotational position of the turntable and/or the vertical height of the drill bit between each drilling operation, as well as the movement of the concrete structures onto and off of the turntable, can be time consuming and laborious. 
   Another machine assembly  24  for drilling holes in concrete structures is shown in  FIG. 2 , in which the machine  12  of  FIG. 1  or a similar machine is disposed adjacent a pair of turntables  20   a  and  20   b  which are positioned side-by-side. The machine  12  is mounted on a set of tracks  26  adjacent the turntables  20   a  and  20   b  and is movable along the tracks  26  to traverse along a horizontal axis between positions in which the machine  12  is aligned with a respective turntable  20   a  or  20   b . The operation of the drilling machine  12  is otherwise identical or similar to that described above. 
   Thus, the operation of assembly  24  involves five movement axes, including a horizontal traverse axis, a horizontal drilling axis, and a vertical adjustment axis associated with machine  12 , as well as a pair of vertical rotational axes associated with turntables  20   a  and  20   b , respectively. 
   Assembly  24  represents an improvement over assembly  10  described above in that the drilling machine  10  of assembly  24  may drill holes in a first concrete structure CS mounted to a first turntable  20   a  while a second concrete structure CS is moved onto or off of the second turntable  20   b . Thereafter, the machine  12  traverses along tracks  26  and the horizontal traverse axis from the first turntable  20   a  to the second turntable  20   b  and then performs drilling operations with respect to the concrete structure CS on the second turntable  20   b  while the concrete structure CS on the first turntable  20   a  is removed and replaced with another concrete structure. 
   Although the assembly shown in  FIG. 2  alleviates the need to entirely stop the operation of the machine while concrete structures are moved onto or off of a given turntable, the need to adjust the rotational position of a turntable and/or the vertical height of the drill bit between each drilling operation, as well as the traversing movement of machine  12  along tracks  26 , may be time consuming and laborious. Also, the tracks  26  of the assembly  24  are mounted along, and cover, a relatively large area of the building floor on the side of the first and second turntables  20   a  and  20   b  on which machine is disposed. Further, the machine must be anchored securely in place prior to drilling to reduce vibrations and prevent the rotational torque of the drill bit from interfering with the lateral position of the drilling machine. 
   What is needed is a drilling machine assembly for concrete structures which is an improvement over the foregoing. 
   SUMMARY OF THE INVENTION 
   The present invention provides a drilling assembly for drilling holes in concrete structures. The assembly includes a base assembly defining a longitudinal axis and adapted to support at least two concrete structures, for example, on turntables positioned in spaced apart relation along the longitudinal axis. A drilling machine is movably mounted to the base assembly between the turntables for movement along the longitudinal axis, and includes a drill assembly having first and second drill bits each substantially aligned along the longitudinal axis and facing substantially opposite directions. In this manner, the drilling machine includes an in-line, dual drill bit assembly which allows the machine to move along a single horizontal axis for both drilling operations and for traversing between the turntables. Advantageously, the present assembly combines the traverse and drilling axes of the drilling machine into a single horizontal axis, thus eliminating the need to traverse the machine between a pair of turntables along a first horizontal axis and to perform drilling operations along a second horizontal axis. 
   In one embodiment, the assembly includes a base assembly having a track disposed along its longitudinal axis, and a pair of turntables disposed on opposite ends of the track. The drilling machine includes a frame mounted on the track for traversing movement therealong between the turntables, the frame supporting the drive unit and the drill assembly. The drill assembly is vertically adjustable with respect to the frame to vary the height of the drill bits. In operation, the drilling machine moves along a horizontal drill axis to drill holes in a first concrete structure mounted to the first turntable, and thereafter may traverse along the same axis using the same movement mechanism to move from the first turntable toward the second turntable to perform drilling operations on a second concrete structure supported by the second turntable. 
   Advantageously, the present assembly combines the drilling axis of the machine with the traverse axis of the machine and performs both drilling and traversing operations using the same movement mechanism to facilitate higher productivity. Additionally, the track of the base assembly is disposed between the turntables such that a minimum of floor space is required to operate the machine, allowing personnel to move about the machine and the turntables as necessary without being impeded by the tracks of the base assembly. 
   In one form thereof, the present invention provides a drilling assembly for drilling holes in concrete structures, the drilling assembly including a base assembly defining a longitudinal axis and adapted to support at least two concrete structures; and a drilling machine mounted with respect to the base assembly for movement along the longitudinal axis, the drilling machine including a frame; a drive unit; and a drill assembly driven by the drive unit, the drill assembly including first and second drill bits each substantially aligned along the axis and facing in substantially opposite directions. 
   In another form thereof, the present invention provides a drilling assembly for drilling holes in concrete structures, the drilling assembly including a base assembly, including first and second concrete structure supports spaced from one another and disposed along a longitudinal axis; and a track disposed between the first and second concrete structure supports and aligned along the longitudinal axis; and a drilling machine movable along the track, the drilling machine including a frame; and dual in-line drill bit means for alternately traversing and drilling in opposite directions along the longitudinal axis. 
   In another form thereof, the present invention provides a drilling assembly for drilling holes in concrete structures, the drilling assembly including a base assembly defining a longitudinal axis and adapted to support at least two concrete structures; and a drilling machine mounted with respect to the base assembly for movement along the longitudinal axis, the drilling machine including a frame; a drive unit and at least one drill bit rotatably driven by the drive unit; and a rotatable turret assembly upon which the drive unit is mounted, the turret assembly rotatable with respect to the frame to move the drill bit between a first position in which the drill bit is aligned along the longitudinal axis facing in a first direction and a second position in which the drill bit is aligned along the longitudinal axis facing in a second direction opposite the first direction. 
   In a further form thereof, the present invention provides a method of drilling holes in concrete structures, including the steps of drilling a hole in a first concrete structure by moving a drill bit of a drill assembly toward and away from the first concrete structure along a first axis; and drilling a hole in a second concrete structure positioned on a side of said drill assembly opposite said first concrete structure by moving a drill bit of the drill assembly toward and away from the second concrete structure along the first axis. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
       FIG. 1  is a side view of a first known drilling assembly; 
       FIG. 2  is a top view of a second known drilling assembly; 
       FIG. 3  is a first perspective view of a drilling assembly according to a first embodiment of the present invention; 
       FIG. 4  is a second perspective view of the drilling assembly, showing the drilling machine disposed in an intermediate position in between the turntables of the base assembly; 
       FIG. 5  is a third perspective view of the drilling assembly, showing the drilling machine performing drilling operations on a first concrete structure disposed on a first turntable assembly; 
       FIG. 6  is a fourth perspective view of the drilling assembly, showing the drilling machine performing drilling operations on a second concrete structure disposed on a second turntable assembly; 
       FIG. 7  is a perspective view of a drilling assembly according to a second embodiment of the present invention, showing a drilling machine including a drilling assembly rotatably mounted to the frame of the drilling machine to facilitate rapid exchanging of drill bits; and 
       FIG. 8  is a perspective view of a drilling assembly according to a third embodiment of the present invention, including a pair of drilling machines disposed respectively between a set of three turntable assemblies. 
   

   Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention any manner. 
   DETAILED DESCRIPTION 
   Referring to  FIGS. 3-6 , a drilling assembly  30  in accordance with an exemplary embodiment of the present invention is shown. Drilling assembly  30  generally includes base assembly  32  for supporting concrete structures CS, a drilling machine  34  which is movable along base assembly  32  as described below, and control unit  36  ( FIG. 3 ). 
   Base assembly  32  generally includes a pair of first and second turntable assemblies  38   a  and  38   b  and a track  40  disposed between the turntable assemblies  38   a  and  38   b , with the turntable assemblies  38   a  and  38   b  and track  40  disposed along a longitudinal axis L 1 -L 1  of the drilling assembly  30 . Each turntable assembly  38   a  and  38   b  generally includes a base frame  42  which may be secured to the floor of a building, and a turntable  44  rotatably supported on base frame  42  in a suitable manner. A concrete structure CS may be supported on each turntable assembly  38   a  and  38   b  for performing drilling operations with respect to the concrete structure, and the concrete structure may be rotated on each turntable assembly  38   a  and  38   b  for drilling one or more holes in the walls of the concrete structure in the manner described below. Track  40  generally includes a pair of rails  46  which may be secured to the floor of a building. Drilling machine  34  is movable along rails  46  for drilling and traversing movement along the longitudinal axis L 1 -L 1  of the drilling assembly  30  in the manner described below. 
   Drilling machine  34  generally includes a frame  52  including base frame  54 , a plurality of vertical supports  56 , and upper frame  58 . A turret assembly  60  includes upper and lower plates  62  and  64 , and is slidably mounted to vertical supports  56  of frame  52  for vertical movement therealong. A pair of hydraulic cylinders  66  are mounted between base frame  54  and upper frame  58  and are connected to turret assembly  60 . Hydraulic cylinders  66  support the weight of turret assembly  60  with respect to vertical supports  56 , and the position of turret assembly  60  is vertically adjustable along vertical supports  56  by pneumatic cylinders  66  in the manner described below. 
   Base frame  54  includes a frame drive unit  68 , such as an electrical or hydraulic motor, for example. In one embodiment, frame drive unit  68  drives a belt and cog assembly (not shown) for moving frame  52  of drilling machine  34  along rails  46  of track  40  by engaging an endless toothed belt  70  mounted with respect to track  40 , with base frame  54  including suitable rollers or wheels (not shown) movable along rails  46  of track  40 . Other drive assemblies by which drilling machine  34  may be moved along rails  46  of track  40  for drilling and traversing movements between turntable assemblies  38   a  and  38   b , such as belt drive, friction wheel drive, cable drive, or gear drive assemblies, may be apparent to one of ordinary skill in the art. 
   Drill assembly  72  is mounted on upper plate  62  of turret assembly  60 , and generally includes a drive unit  74  which drives a common shaft or spindle  76  aligned with longitudinal axis L 1 -L 1 . Shaft  76  includes opposite first and second ends to which first and second drill bits  78  and  80  are respectively secured. Drill bits  78  and  80  are cylindrically shaped for drilling round holes in concrete structures, and may be of various diameter sizes. Alternatively, drive unit  74  may separately drive drill bits  78  and  80  via separate shafts. In one embodiment, drive unit  74  includes a hydraulic motor and a multiple-speed transmission for varying the speed/torque at which shaft  76  and drill bits  78  and  80  are driven. 
   Control unit  36  ( FIG. 3 ) may be positioned at a location that is spaced from base assembly  32  and drilling machine  34 , and includes a user-operable control interface  82  for controlling the operation of turntable assemblies  38   a  and  38   b  and drilling machine  34 . In the present embodiment, control unit  36  also includes a hydraulic reservoir  84  and hydraulic pump  86 . Hydraulic pump  86  is in fluid communication with the hydraulic motor of drive unit  74  of drill assembly  72  via suitable conduits (not shown), and is also in fluid communication with other hydraulic motors (not shown) associated with turntable assemblies  38   a  and  28   b  via additional conduits (not shown). The hydraulic motors of turntable assemblies  38   a  and  38   b  may be hydraulically driven to rotate turntables  44 , such as by driving a pneumatic tire (not shown) which engages the underside of each turntable  44  to rotate same. The hydraulic motors associated with turntable assemblies  38   a  and  38   b  may be selectively controlled to rotate turntables  44  along known angular intervals. 
   Drilling assembly  30  may operate in one embodiment as follows. First, pre-cast concrete structures CS are mounted on turntable assemblies  38   a  and  38   b  for drilling one or more holes in each of the concrete structures. Drilling machine  34  is moved from a “home” position shown in  FIGS. 3 and 4  in which same is spaced between turntable assemblies  38   a  and  38   b , for example, to provide sufficient clearance around turntables  44  for concrete structures to be loaded onto turntables  44 . Thereafter, drilling machine  34  is traversed along track  40  by frame drive unit  68  as described above to place a selected drill bit  78  or  80  of drill assembly  72  proximate the concrete structure. As necessary, hydraulic cylinders  66  of frame  52  may be actuated to adjust the vertical positioning of turret assembly  66  with respect to vertical supports  56  of frame  52  and hence, the vertical position of shaft  76  and drill bits  78  and  80  to a desired vertical position relative to the concrete structure. Thereafter, hydraulic pump  86  and the hydraulic motor of drive unit  74  of drill assembly  72  are actuated to rotate shaft  76  and drill bits  78  and  80  and concurrently, frame drive unit  68  is actuated to move drilling machine  34  along track  40  and longitudinal axis L 1 -L 1  to engage drill bits  78  with a first concrete structure CS for drilling a hole therein. After drill bit  78  penetrates the wall of concrete structure CS, frame drive unit  68  is actuated to traverse drilling machine  34  in an opposite direction along track  40  and longitudinal axis L 1 -L 1  away from concrete structure CS and thereby remove the drill bit  78  from engagement with the concrete structure CS, optionally with either forward or reverse rotation of drill bit  78  as controlled by drive unit  74  of drill assembly  72 . Of course, drill bit  80  may be used to drill one or more holes into a concrete structure CS on second turntable assembly  38   b  prior to the use of drill bit  78  for drilling one or more holes into a concrete structure CS on first turntable assembly  38   a.    
   Thereafter, drilling machine  34  may be traversed along track  40  and longitudinal axis L 1 -L 1  toward the second concrete structure CS to perform drilling operations on the second concrete structure CS in an analogous manner as described above with respect to the first concrete structure CS. Concurrent with traversing movement of drilling machine  34 , the vertical positioning of turret assembly  66  and hence, the vertical position of shaft  76  and drill bits  78  and  80  may be adjusted to a desired vertical position as described above. Alternatively, drilling machine  34  may be traversed a slight distance away from the first concrete structure CS, followed by rotation of the turntable  44  of turntable assembly  38   a  to rotate first concrete structure CS, followed by drilling another hole at a desired vertical location in the first concrete structure CS. 
   Additionally, after drilling a first hole in first concrete structure CS, drilling machine  34  may be traversed along track  44  and longitudinal axis L 1 -L 1  to perform a desired drilling operation with respect to second concrete structure CS while the turntable  44  of first turntable assembly  38   a  and first concrete structure CS are rotated to a desired position in which a subsequent hole may be drilled in the first concrete structure CS. Other variations on the foregoing operations may be apparent to one of ordinary skill in the art based on the teachings herein. In this manner, drilling machine  34  may be traversed with concurrent selected operation of turntable assemblies  38   a  and  38   b  to maximize the productivity of drilling multiple holes in each of concrete structures CS and CS. 
   Further, turntable assemblies  38   a  and  38   b  may be configured for transverse movement at an angle with respect to longitudinal axis L 1 -L 1 , such as perpendicular to longitudinal axis L 1 -L 1 , for example. Specifically In  FIG. 3 , turntable assembly  38   a  is configured for transverse, shifting movement by a drive mechanism along rails (not shown) along directions perpendicular to longitudinal axis L 1 -L 1  so that a pair of side-by-side holes may be drilled in concrete structure CS at a selected height. 
   Advantageously, the longitudinal axis L 1 -L 1  along which drilling machine  34  traverses between turntable assemblies, and the axis along which drilling machine  34  drills with respect to any concrete structure CS on turntable assemblies  38   a  and  38   b , is the same axis, such that traversing of drilling machine  34  and the drilling operations of drilling machine  34  both occur via the same mechanism along a common axis, as opposed to known drilling assemblies, such as that described above and shown in  FIG. 2 , in which the axis along which the drilling machine traverses is different from the axis along which the drilling machine drills. Additionally, because the traversing movement of drilling machine  34  and the drilling operations of drilling machine  34  occur via the same movement mechanism, namely, frame drive unit  68 , the use of a separate, pneumatic drill drive as in known drilling machines is obviated in drilling machine  34 . 
   Referring to  FIG. 7 , a drilling machine  34  in accordance with another exemplary embodiment of the present invention includes upper plate  62  of turret assembly  66  rotatably mounted with respect to lower plate  64  in a suitable manner. Drill assembly  72  may include two or more separate shafts  76   a  and  76   b  to which drill bits  78 ,  80 ,  88 ,  90 , of various sizes are mounted. Upper plate  62  of turret assembly  66  may be rotated manually or by a suitable drive mechanism (not shown) in order to align various drill bits along longitudinal axis L 1 -L 1  such that the drill bits may be easily interchanged for drilling holes of various sizes in the concrete structures. 
   A drilling assembly  30  is shown in  FIG. 8  in accordance with another exemplary embodiment of the present invention, in which multiple turntable assemblies  38   a ,  38   b ,  38   c  are arranged with multiple drilling machines  34  along a common longitudinal axis L 1 -L 1  to increase the productivity of drilling assembly  30 . Other arrangements of turntable assemblies and drilling machines along one or more common longitudinal axes may be apparent to one of ordinary skill in the art based on the teachings herein. 
   While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.