Abstract:
A system and method for inspecting mowers that utilizes a video camera to allow a single technician to look directly at a selected reference point on a crankshaft of the operating mower to thereby determine if the crankshaft is bent.

Description:
BACKGROUND  
       [0001]     The following relates generally to a system and method for inspecting mowers and, more particularly, relates to a system and method for allowing a user to visually determine if a mower has a bent engine crankshaft.  
         [0002]     Mowers, such as the type described and illustrated in U.S. Pat. No. 6,688,095 which is incorporated herein by reference in its entirety, are well known. By way of example and with reference to prior art  FIG. 1 , known mowers  100  generally include a mower deck  107  defining a first or upper surface  110  to which an engine  106  is attached. The engine  106  is preferably oriented such that the engine crankshaft  104  extends vertically downward into a cutting chamber  109  defined at least in part by the deck  107 . A cutting blade  102  is then attached to a lower end  105  of the crankshaft  104  by way of a blade coupler assembly  200 . During operation, the crankshaft  104  rotates the blade coupler  200  at a speed sufficient to cause the cutting blade  102  to sever grass that passes beneath the cutting blade  102 . In the case where the mower is a self-propelled, walk-behind mower, rotation of the crankshaft  104  may also be used to drive front and/or rear wheels  108  by means of a drive pulley  202 , a drive belt  110 , and a transmission  111 .  
         [0003]     When the cutting blade  102  of a mower strikes a stationary object during operation, the impact between the cutting blade  102  and the stationary object may stop the cutting blade  102  at the point of impact, at least for an instant. During this moment of impact the retreating portion of the cutting blade  102  will, however, tend to keep moving forward owing to the kinetic energy stored in the cutting blade  102 . Undesirably, the forces associated with the stopping of one portion of the cutting blade  102  and the continued moving of the opposite portion of the cutting blade  102  can cause the crankshaft  104  to bend. Once the crankshaft  104  is bent, continued operation of the mower will typically lead to various of the mower components being further damaged as a result of shear stress forces, vibration, etc.  
         [0004]     Presently, to inspect a mower for purposes of determining if the crankshaft is bent, the mower is required to be tilted so that the cutting blade and crankshaft, which are located under the mower deck, become visible. Since a technician that is responsible for tilting the mower typically cannot also see the cutting blade and crankshaft adequately enough to determine if the crankshaft is bent, this process requires the use of a second technician that has the responsibility of observing the cutting blade and crankshaft while the first technician tilts and operates the mower. Thus, it will be appreciated that this currently utilized method for inspecting mowers can be dangerous, e.g., the mower can fall over creating a hazard to nearby associates, can potentially damage the mower, e.g., the mower can be tilted to the wrong side, and is costly and time consuming since it requires the services of at least two technicians.  
       SUMMARY  
       [0005]     To address these and other problems associated with presently utilized methods for inspecting mowers, the present invention provides a system and method for inspecting mowers that is non-destructive and non-intrusive. More particularly, the present invention utilizes a video camera over which the mower is positioned. The video camera allows a single technician to look directly at a selected reference point on the crankshaft by means of a video monitor to thereby monitor movement of the crankshaft as the mower is operated. Thus, using the inventive system, the single technician can verify if the crankshaft is bent by monitoring the operating crankshaft and looking for excursions from the centerline as the crankshaft rotates.  
         [0006]     A better understanding of the objects, advantages, features, properties and relationships of the subject invention will be obtained from the following detailed description and accompanying drawings which set forth illustrative embodiments which are indicative of the various ways in which the principles of the invention may be employed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     For a better understanding of the invention described hereinafter, reference may be had to preferred embodiments shown in the following drawings in which:  
         [0008]      FIG. 1  illustrates a prior art mower by way of example only;  
         [0009]      FIG. 2  illustrates an exemplary mower inspection system constructed in accordance with the principles of the subject invention;  
         [0010]      FIG. 3  illustrates a view of the mower blade as seen by the camera of the system of  FIG. 2 ; and  
         [0011]      FIG. 4  illustrates a comparison between the view of an unbent crankshaft and the view of a crankshaft that is bent during operation of a mower. 
     
    
     DETAILED DESCRIPTION  
       [0012]     With reference to the figures, in which like numerals refer to like elements,  FIG. 2  illustrates an exemplary inspection station  300  that allows a user to visually determine if a mower  100  has a bent engine crankshaft  104 . To this end, the inspection station  300  includes a video camera  302  which is adapted to provide a video signal to a monitor  304  by means of, for example, a video cable  306 . To allow a mower  100  to be positioned above the video camera  302  such that the crankshaft  104  of the mower  100  is within the field of view  308  of the video camera  302 , the inspection station  300  may include an elevated platform  310  that is adapted to support the mower  100 . Preferably, the elevated platform  310  includes a ramp surface  312  that allows the mower  100  to be easily moved onto the elevated platform  310  and into the general area of the field of view  308  of the video camera  302 . The elevated platform  310  may additionally be provided with a means for maintaining the mower  100  in a stationary position once the mower  100  is positioned upon the elevated platform  310  in a desired location with respect to the video camera  302 . The means for maintaining the mower  100  in a stationary position may include, by way of example only, a device that functions to clamp the front wheels  108  of the mower  100  to the surface of the elevated platform  310 , a device that functions to clamp the front wheels  108  to a front stop  312  of the elevated platform  310 , or the like.  
         [0013]     Once the mower  100  is moved upon the platform  310  and into the field of view  308  of the video camera  302  (and preferably anchored to the platform  310 ), the mower  100  may be started to thereby allow the technician to inspect the condition of the crankshaft  104 . More particular, the technician may inspect the condition of the crankshaft  104  by viewing the video image captured by the video camera  302  on the monitor  304 . If the crankshaft  104  is normal, i.e., unbent, the technician will view a video image of the rotating crankshaft  104  similar to image  400  of  FIG. 4 , i.e., the image will have a steady, generally circular appearance. If, however, the crankshaft  104  is bent, the technician will view a video image of the rotating crankshaft  104  that shows a wobbling image, such as illustrated in image  402  of  FIG. 4 .  
         [0014]     To maintain a copy of the video image viewed during the inspection process, for example to allow a customer to view the same video image that was viewed by the technician during the inspection process, the inspection station  300  may also include a video capture device  316  that is also linked to the video camera  302 . The video capture device  316  may be a video cassette recorder or the like. It is also contemplated that video images captured using the video capture device  316  may be stored on a server accessible database to thereby allow for viewing of the captured video images via a network, such as the Internet. In this manner, a customer may access the server via the network, provide some indicia that serves to identify the customer (e.g., phone number, name, log-in/password, etc.), and be provided with an opportunity to view and/or download the video capture of the inspection of their mower.  
         [0015]     In a further embodiment of the invention, the inspection system  300  may also be provided with a laser emitting device  318  that may be used to provide a point of light to the rotating crankshaft  104  as illustrated in  FIG. 3 . As will be understood, the point of light can be used to assist the technician in locating and viewing the centerline of the engine crankshaft  104 . Being able to view a visibly demarked centerline of the engine crankshaft  104  during the inspection process will assist the technician in verifying whether or not the rotating crankshaft  104  has any excursions from that centerline which, as discussed above, are indicative of a bent crankshaft. While not required, the laser emitting device  318  may have an associated proximity switch  320  which functions to inhibit the laser emitting device  318  from emitting light when the mower  100  is not positioned on the elevated platform  310  over the video camera  302  and light emitting device  318 . In this manner, the proximity switch  320  can be used to prevent the emitting of light into the area above the elevated platform  310  when that area is not shielded by the mower platform  107 . It will be appreciated that, while the illustrated example shows the light from the laser emitting device  318  being provided directly to the crankshaft  104 , the light from the laser emitting device  318  may also be directed to the crankshaft  104  by means of a mirror.  
         [0016]     To allow the camera  302  and/or laser emitting device  318  to be easily moved relative to the mower  100  to thereby allow for the field of view  308  of the video camera  302  to be adjusted and/or the laser emitting device  318  to be moved for the purpose of placing the light emitted from the laser emitting device  318  on the centerline of the crankshaft, the camera  302  and/or the laser emitting device  318  may be carried upon a sub-platform  320  that is itself moveable relative to the elevated platform  310 . In this regard, the sub-platform  320  may be moveable in one, two, or three dimensions for this purpose. In the situation where a mirror is utilized to direct light from a laser emitting device  318  onto the crankshaft  104 , the mirror may be adjustable to allow for the light emitted from the laser light device  318  to be directed to the centerline of the crankshaft  104 . It will be appreciated that the placing the sub-platform  320  in the desired position may itself be facilitated by the technician viewing video images captured by the video camera  302  on the monitor  304 .  
         [0017]     To provide a measure of protection to the components of the inspection system  300  during the inspection process, in particular the video camera  302  and laser emitting device  318 , a plexiglass or similar transparent/translucent shielding  322  may be provided to the elevated platform  310  in an area under which would be positioned the video camera  302  and laser emitting device  318 . As will be appreciated, as the mower  100  is operated during the inspection process particulates, etc. may be caused to be dropped or propelled from the mower  100 . Thus, the shielding  322  will function to protect the noted components from such flying debris.  
         [0018]     From the foregoing description it will be appreciated that the subject invention provides a system and method for inspecting a mower which overcomes the problems previously discussed. It will be also appreciated by those skilled in the art that, while specific embodiments of the invention have been described in detail, various modifications and alternatives to those details could be developed in light of the overall teachings of this disclosure. For example, the inspection of the rotating crank shaft  104  may also include the use of a light that is strobed onto the rotating crankshaft  104  to thereby further assist the technician in viewing the crankshaft  104  as it rotates. In addition, the video capture system may provide for the capturing of single frame images that may be overlayed or otherwise compared to one another to thereby allow any wobble of the rotating crankshaft to be easily seen. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any equivalents thereof.