Abstract:
A remote viewing device including a hand-holdable control unit. The control unit supports a display device and a drive assembly. The drive assembly is removably attached to the control unit and provides mechanical power to an insertion tube. A distal end of the insertion tube includes an inspection head for insertion into a structure for imaging the interior of the structure. The insertion tube is removably attached to the drive assembly by a connector assembly, where the connector assembly is operable, when attached, to convey mechanical power from the drive assembly for moving the articulated tip in response to a user input at the control unit, and to convey images from the inspection head to the display device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/748,082, filed Dec. 7, 2005, which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to the field of non-destructive examination, and more particularly to vision systems for remote viewing of inaccessible test areas. 
     BACKGROUND OF THE INVENTION 
     A variety of remote viewing devices are known for performing visual inspections in generally inaccessible test areas. Borescopes, endoscopes and laparoscopes are examples of remote viewing devices that incorporate a small light-gathering device at the distal end of an elongated inspection tube that is inserted through a small opening to reach a remote viewing area. The light-gathering device may be a fiber optic cable that transmits the gathered light through the inspection tube to a receiving device at the proximal end of the inspection tube, or it may be a camera that transmits a video signal through the inspection tube to a display located remote from the viewing area. 
     U.S. Pat. No. 5,373,317, incorporated by reference herein, describes a borescope that may be used for inspecting restricted areas of a component such as a turbine or electrical generator without necessitating the disassembly of the component. The borescope of the &#39;317 patent includes a hand-held control unit incorporating a joystick that functions to control an articulated tip at a distal end of an insertion tube. The control unit also includes a video display device for providing images of a test area collected by a video camera forming part of a viewing head attached to the articulated tip. A light source provides light to the test area via a fiber optic bundle that passes through the hand-held control unit and the insertion tube to the viewing head. The servomotors that move the articulated tip in response to control of the joystick are also mounted within a proximal end of the control unit to provide a balanced construction to the hand-held control unit. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the invention, a remote viewing device is provided comprising a hand-holdable control unit, and a display device mounted to the control unit. A drive assembly is removably attached to the control unit for providing mechanical power. The device further includes an insertion tube comprising a proximal end and an articulated tip at a distal end. An inspection head is associated with the articulated tip, the inspection head being configured for imaging the interior of an object. A connector assembly removably interconnects the control unit and the proximal end of the insertion tube. The connector assembly is operable, when connected, to convey the mechanical power from the drive assembly for moving the articulated tip in response to a user input at the control unit, and to convey images from the inspection head to the display device. 
     In accordance with another aspect of the invention, a remote viewing device is provided comprising a hand-holdable control unit, and a display device mounted to the control unit. A drive assembly is provided for providing mechanical power. The device further includes an insertion tube comprising a proximal end and an articulated tip at a distal end. An inspection head is associated with the articulated tip, the inspection head being configured for imaging the interior of an object. A connector assembly removably interconnects the control unit and the proximal end of the insertion tube. The connector assembly is operable, when connected, to convey images from the inspection head to the display device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the present invention will be better understood from the following description in conjunction with the accompanying Drawing Figures, in which like reference numerals identify like elements, and wherein: 
         FIG. 1  is a schematic illustration of a remote viewing apparatus in accordance with the present invention; 
         FIG. 2  is a perspective view of an articulated tip drive assembly for the remote viewing apparatus of  FIG. 1 ; and 
         FIG. 3  is an exploded view of a drive portion of the drive assembly of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A prior art borescope as described in U.S. Pat. No. 5,373,317 is susceptible to failure as a result of the failure of any of its constituent parts, most notably the fiber optic cable, camera, articulated tip, insertion tube, electronics and servomotors. The present inventors have recognized that the expense of using, maintaining and repairing prior art borescopes is increased because the borescopes are assembled as integrated units. Further, when planning for the inspection of an industrial component such as an electrical generator or a gas or steam turbine, the user must anticipate the areas to be inspected and must select a borescope that is capable of penetrating the component to reach the desired test areas to provide the desired image. 
     Two key variables that are considered during inspection planning are the length of the insertion tube and the diameter of the insertion tube. An insertion tube that is too short to reach the test area from the access point is obviously problematic, and thus a borescope having an insertion tube that is longer than required will be selected. However, a borescope having an insertion tube that is longer than necessary for the inspection presents unnecessary handling and packaging difficulties and is more costly than a similar borescope having a shorter insertion tube. The diameter of the insertion tube selected for use presents perhaps an even greater concern than the length of the insertion tube. Many inspection activities require the insertion tube to navigate a tortuous path from an access port to the test area. A relatively larger diameter insertion tube generally will exhibit reduced flexibility when compared to a relatively smaller diameter insertion tube, thus making it more difficult to manipulate the larger diameter tube. Accordingly, there is a tendency for the user to select a borescope having an insertion tube diameter smaller than necessary to ensure that all test areas can be accessed, even in the event of encountering an unexpected obstruction during the inspection. However, the present inventors have noted that insertion tube field failure rates are closely and dramatically associated with the tube diameter. For example, in the range of 5-8 mm diameter insertion tubes, it is not unknown to experience a doubling of the failure rate for each 1 mm reduction in tube diameter. 
     The present inventors have developed a remote vision apparatus that innovatively addresses many of the problems experienced with prior art devices.  FIG. 1  is a schematic illustration of one embodiment of an improved remote viewing apparatus  10 . Advantageously, the remote viewing apparatus  10  incorporates quick-disconnect interconnectivity of its constituent parts to provide flexibility during the configuration of the apparatus and to facilitate field reparability in the event of a component failure. 
     The remote viewing apparatus  10  includes a control unit  12 , an inspection head  14 , and an insertion tube  16  connected therebetween. The control unit  12  is preferably sized and shaped to allow it to be hand held and manually manipulated. Associated with the control unit  12  are a drive assembly  18 , a display  20 , a processor  22  and associated memory  24 , a power supply  26  and various input/output devices  28 . The inspection head  14  is configured for imaging objects, such as a generally inaccessible interior area of a turbine engine. The inspection head  14  includes a camera  30  and a light source such as light emitting diodes (LEDs)  32  which may be removably attached to an articulated tip  34  at a distal end  36  of the insertion tube  16 . As will be described more fully below, remote viewing apparatus  10  is modularized to facilitate the configuration of the unit for various inspection activities and to facilitate the repair of the unit in a field inspection environment. 
     The insertion tube  16  is removably connected to the control unit  12  via a connector assembly  38  that conveniently may be engaged and disengaged in a field-testing environment. The connector assembly  38  includes mating first and second connector halves  38   a ,  38   b  ( FIG. 2 ) that function, when connected, to convey mechanical power from the drive assembly  18  to the articulated tip  34 , and to convey electrical power from the control unit  12  to energize the light source  32  and the camera  30 , and to convey video signals from the camera  30  to the display device  20 . The connector assembly  38  allows the apparatus  10  to be configured with any number of different insertion tubes  16  having differing lengths and/or cross-sectional dimensions, i.e., diameters, to optimize the performance of the unit for a particular inspection activity. The insertion tube  16  initially used at a job site may be selected to have as large a diameter as practical in order to maximize the durability of the remote viewing apparatus. If the larger-sized insertion tube cannot be successfully used, an insertion tube  16  having a smaller diameter may be field-installed for completing the inspection. Similarly, should the insertion tube  16  fail for any reason, a replacement insertion tube  16  may be installed by simply disconnecting the second connector half  38   b  of the failed tube from the first connector half  38   a  at the control unit  12  and reconnecting the replacement tube which is fabricated with a compatibly configured mating second connector half  38   b.    
     Other component parts of the remote viewing apparatus  10  may be conveniently replaced in the event of component failures. For example, camera  30  and light source  32  may be connected to the articulated tip  34  via plug-in connectors. The camera  30  in one embodiment may be a 4.3 mm SUPER HAD CCD brand color camera sold by Sony Corporation. The light source  32  in one embodiment may be light emitting diodes with a total output of about 2,600 lumens. Alternatively, the light source  32  may be a fiber light guide for transmitting light energy through the insertion tube  16  to the inspection head  14 , for example, for transmitting light from a light source at the control unit  12  to the inspection head  14 . 
     Software for imaging processing and other desired functions of the remote viewing apparatus  10  may reside in an easily-replaceable memory device  24 , for example, a known type of memory card such as a flash card or memory stick, for execution by processor  22 . The software may include an operating system, image acquisition and control, file management, digital zoom, text annotation, graphic annotation, articulation control, light source control, electronic distance measurement, and/or auto-detect/recognition functions as may be desired for a particular application. 
     The control unit  12  may be ergonomically designed for comfortable hand-held operation. Its size and shape may be similar to current video game controllers and may, for example, include left and right handle portions  41   a  and  41   b  ( FIG. 1 ) for support by the left and right hands of an operator. The monitor  20  may be a high-resolution liquid crystal display (LCD). One or more joystick controls  40  may be provided for user input for control of the movement of the articulated tip  34 . One or more button switches  42  may be provided for further user input to processor  22  and/or for manipulation of the inspection head  14 . Accordingly, the control unit  12  is hand-holdable for an operator to comfortably hold the control unit  12  between the operator&#39;s hands while also manipulating the joystick controls  40  and switches  42 . A remote input/output (I/O) function  44 , such as a USB port or RF connection, may be used for communication between the control unit  12  and remote locations such as a remote viewing station. Batteries and/or A/C power may be used to energize a power supply  46 . 
       FIG. 2  is a perspective view of one embodiment of a drive assembly  18  for moving the articulated tip  34 . The drive assembly  18  may be removably attached to the control unit  12  via a mounting plate  48  and fasteners (not shown) passing through mounting holes  50 . The drive assembly  18  of this embodiment includes two servomotors  52   a ,  52   b  connected via respective gear trains housed in a gear box  54  to respective pairs of cable pull racks  56   a ,  56   b . The gear trains are arranged so that rotational movement of one of the motors  52   a  or  52   b  results in respective coordinated pull/push linear movement of the associated pair of cable pull racks  56   a  or  56   b.    
       FIG. 3  is an exploded view of a drive portion  19  of the drive assembly  18  of  FIG. 2  illustrating component part details. Drive motors  52   a ,  52   b  each provide rotary motion via respective output shafts  62  to a respective motor side miter gear  64 . Rotary power is transferred form the motor side miter gears  64  to respective drive shafts  66  via respective shaft side miter gears  68  engaged with the motor side miter gears  64 . A spur gear  70  attached to each respective drive shaft  66  imparts linear motion in opposing directions to the respective pair of cable pull racks  56   a  and  56   b . The cable pull racks  56   a ,  56   b  are formed to include teeth  72  that interface with respective top and bottom sides of the spur gears  70  to provide the coordinated opposing motion. 
     Referring to  FIGS. 2 and 3 , the pairs of pull racks  56   a ,  56   b  are detachably attached to respective ends of cable pairs  57   a ,  57   b  passing through the insertion tube  16  via the connector assembly  38  to provide articulation in both the x-axis (e.g. cable pair  57   a ) and y-axis (e.g. cable pair  57   b ) to the distal end of the articulated tip  34 . The first connector half  38   a  is disposed at a distal end of a drive assembly housing  58  supported on the mounting plate  48 , and includes ends of the pairs of pull racks  56   a ,  56   b  and an electrical connector element  55   a.    
     The second connector half  38   b  is preferably disposed within a connector housing  61  located at the proximal end  60  of the insertion tube  16  and comprises pairs of cable end couplings  51   a ,  51   b  for coupling to the ends of the pairs of pull racks  56   a ,  56   b  and an electrical connector element  55   b  for coupling with the electrical connector element  55   a . The pairs of cable end couplings  51   a ,  51   b  are attached to the ends of respective cable pairs  57   a ,  57   b . Distal ends of the pairs of pull racks  56   a ,  56   b  are each threaded, and the pairs of the cable end couplings  51   a ,  51   b  each include threaded end portions, such as threaded apertures opposite from respective cables of the cable pairs  57   a ,  57   b , for rotatable threaded engagement with the pairs of pull racks  56   a ,  56   b , whereby the cable pairs  57   a ,  57   b  are actuated in longitudinal movement with longitudinal movement of the respective pairs of pull racks  56   a ,  56   b.    
     It may be seen that the drive assembly  18  is supported on the control unit  12  as a replaceable component, permitting ready replacement in the event of a failed drive assembly element, such as, for example, a failure of a servomotor. In particular, the connection of the drive assembly  18  to the insertion tube  16  may be readily detached or reattached at the connector assembly  38  for efficient replacement of the drive assembly  18  as separable component from both the control unit  12  and the insertion tube  16 . 
     While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.