TECHNICAL FIELD

The present disclosure relates generally to a method and apparatus for conducting a non-contact overhead crane runway system survey using a survey apparatus that is alternately located in the crane bay or on a crane bridge girder, and, more particularly, to testing an overhead crane runway beam 3D alignment or an overhead crane runway rail 3D alignment using a 3D laser scanner. The data and profiles generated can be reviewed to ascertain whether the overhead rails conform to alignment specifications.

BACKGROUND OF THE DISCLOSURE

An exemplary overhead crane100, with which exemplary embodiments of the described rail survey system and rail survey data collection methods can be used, is shown inFIG. 1A. The traveling overhead crane100may span a distance between two runway rails101, each runway rail101supported by a runway beam102, and each runway beam102supported by a plurality of support columns (not shown). The runway beam102generally has an “I” shape as shown inFIG. 1B, with an upper flange120upon which the runway rail101rests and a lower flange121connected to the upper flange120via a web122. The runway beam102can be further reinforced with a plurality of stiffeners123that are positioned between the upper flange120and the lower flange121of the runway beam102in a plane that is perpendicular to both the flanges120,121and the web122and placed at intervals along the runway rail101.

The overhead crane100contacts each of the runway rails101with an end carriage103. Each end carriage103includes two or more crane wheels104that contact the runway rail101. For example, each end carriage103shown inFIG. 1Aincludes two crane wheels104. The leading and trailing ends of each end carriage103terminate with a rail sweep105.

The overhead crane100further includes a trolley106that receives power through a trolley festoon116and travels between the two respective end carriages103on a pair of bridge rails107. Each bridge rail107is supported by a bridge girder108. The bridge girder108is driven by a crane motor118along the runway rails101. The trolley106may further include one or more hoisting mechanisms109, each supporting a load hook110through a wire rope115, which can be raised and lowered by each of the respective hoisting mechanisms109to raise and lower cargo. Use of the hoisting mechanisms109to raise and lower cargo, in combination both with the ability of the trolley106to travel back and forth between the two respective end carriages103on the bridge rails107and with the ability of the overhead crane100(as a whole) to travel the length of the crane rails101, allows crane operators to move cargo between any two locations on the loading dock between the crane rails101. Operation of the overhead crane100can be controlled by a crane operator via a push button pendant111connected to a pedant festoon112by a pendant cable113or, alternatively, via a remote control114. The pedant festoon112and the trolley festoon116are slidably suspended from a C-Track117positioned along the bridge girder108. The crane motor118is powered through a high TRO reel system119, which is a type of industrial mobile power feeding system.

Overhead cranes, such as the overhead crane100described above, are used in material handling factories and warehouses around the world to load and unload millions of tons of cargo daily and are crucial to the daily operations performed at each of these respective factories and warehouses. Due to the large scale of such overhead cranes and the heavy loads typically transported by the cranes, proper alignment of runway rails and crane wheels is crucial to their safe and efficient operation, and hence crucial to the daily operations of each business in which they are used. Changes to geometric parameters stated in the project documentation arise not only during installation, but especially during operation of the crane. These changes are caused by various influences such as forces affecting the crane when the crane is moving, crane weight, material depreciation, heat influences, and more.

Alignment standards for crane rails are outlined in the Crane Manufacturers Association of America's specification70and AISE technical report #13. Many types of rail surveys involve time-consuming methods that require the rail to be locked out (i.e., power to the hot rail turned off) and survey personnel to walk the length of the runway.

Although alignment of the runway rails is important, other factors, such as positioning of the crane wheels parallel to their respective runway rails and/or assuring that drive motor output provided to the respective end carriages is equivalent, are also important. Imbalances in motor output to the respective end carriages can cause crane skew even though the runway rails themselves are within tolerance guidelines. These imbalances result in wear on the rails and crane wheels, both of which are costly to repair. Hence, a safe method to quickly and accurately collect rail survey data and to find the root cause of misalignment problems would be very beneficial.

Previous methods of rail surveying have involved using piano wire for straightening sections of rail. When used in conjunction with a tape measure to measure the span between runway rails, this method is not very accurate and is extremely time consuming. Another common method requires setting a transit on the rail while survey personnel walk the length of the rail, stopping at various points to take readings. Although this is a more accurate approach for determining the straightness of individual runway rails, determining the span between runway rails is still dependent on the use of a tape measure. For measurement of runway rail elevation, yet another instrument is required for set-up on the rail. With few exceptions, the known methods for rail surveying refer primarily to techniques for use on train tracks and elevation tracks which are not applicable for use with respect to overhead cranes.

An alternative method is described in U.S. Patent Application Publication No. 2005/0111012 and uses a remotely operated laser to perform a runway survey. This device is not configured, however, to measure the relative positioning of the two rails that support the crane bridge girder (e.g., span alignment or elevation). In addition, the existing alignment systems require manpower to access the crane rail runway beam and begin taking measurements on one side of the bay, work their way to the end of the bay, then do the same thing on the other side of the bay. The rail span value is geometrically calculated and is never directly measured. These methods thus result in suspension of crane operation for the duration of the survey, which translates into increased costs and fiscal and efficiency losses.

Overhead cranes are often the heart of operations in a manufacturing facility. Shutting down an overhead crane can and often does shut down operations. Therefore, operators are reluctant to shut down cranes for maintenance or inspections. The problem becomes how operators can maintain and inspect overhead cranes with minimal or, preferably, no downtime. Accordingly, there is a need for a method of surveying rails of overhead cranes which does not require suspension of crane operation.

Existing rail survey systems require down time and human access to the crane rail. In the past, operators would survey, analyze, and repair crane rails during the same outage period. This practice makes the engineering analysis and design repair the scheduling choke point. Prior methods also limited the ability of operators to seek and vet competitive bids from contractors for the repairs; they also limited the material available to use during the outage.

To overcome the shortcomings of existing rail survey systems, a contact-free rail survey system is provided. An object of the present disclosure is to provide a more efficient approach to surveying the rail alignment of an overhead crane. A related object is to eliminate the need for access to the crane runway rails to complete an alignment survey. Another object is to eliminate or significantly shorten the outage period required to complete the survey. Yet another object is to safely, quickly, and accurately measure crane runway rail, runway beam, runway beam flange camber, runway beam web warp and lean, hot rail alignment, column 3D position and lean, column girder seats, and span during normal operations. A related object is to allow measurements to be taken months or weeks before the scheduled downtime, allowing sufficient time for engineering analysis, design, and competitive bidding for repair.

SUMMARY OF THE INVENTION

To achieve these and other objects, and in view of its purposes, the present disclosure provides a non-contact rail survey system for overhead crane runway beams, crane bridge beams, and structural beams used for bridges and the like. Each crane runway beam has an upper flange and a lower flange linked by a beam web, and a plurality of vertical beam web stiffeners positioned along the beam at intervals. A runway rail is positioned on top of the runway beam. A hot rail is positioned along the upper flange of the crane runway beam. Crane columns each have an upper end and a lower end, with the upper end having a beam seat upon which the crane runway beam rests. The system includes a measurement unit configured to remain stationary during measurement of two runway rails which collectively form a runway. The measuring unit includes a 3-D laser scanner configured to collect data, a support base, and an interface which transmits the data collected by the 3D laser scanner. The system further includes a computing unit with a receiver which receives the 3D laser scanner data transmitted by the interface, a data storage unit, and a processor configured to compute one or more of runway rail 3D alignment, crane runway beam 3D alignment, crane runway beam flange camber, crane runway beam web warp and lean, hot rail 3D alignment, crane column 3D position and lean, crane column beam seats, and direct span measurement.

The present disclosure further provides a non-contact method for measuring 3-D alignment of an overhead crane runway beam having an upper and a lower flange linked by a beam web and having a plurality of vertical beam web stiffeners positioned along the beam at intervals, with a runway rail positioned on top of the runway beam. The method includes the step of providing a measurement unit configured to remain stationary during measurement of two rails which collectively form a runway, wherein the measurement unit includes a 3-D laser scanner on a support base. The method further includes the steps of acquiring a point cloud of a segment of the crane runway beam; converting the point cloud into a triangulated irregular network (TIN) surface; converting the TIN surface into a raster image; detecting edges of the beam web surface segments, wherein each beam web surface segment is delineated by upper and lower runway beam flanges in the vertical dimension and by runway beam stiffeners in the horizontal dimension; identifying runway beam joints; determining an average value of points between two adjacent runway beam joints; determining an average value of points for each beam web surface segment; determining an average value of points between two adjacent runway beam joints; measuring the distance from each web surface segment to a crane bay centerline at the bottom, middle, and top locations along the runway beam; and determining the deviation between: the distance from the crane bay centerline and the average value of points between two adjacent runway beam joints, and the distance from the crane bay centerline and each beam web surface segment at the top, bottom, and middle locations, wherein when the deviation exceeds a pre-determined threshold the runway beams are not aligned, and wherein when the deviation is at or below the pre-determined threshold the runway beams are aligned.

The present disclosure further provides a non-contact method for measuring 3-D alignment of an overhead crane runway rail. The method includes the step of providing a measurement unit configured to remain stationary during measurement of two rails which collectively form a runway, wherein the measurement unit includes a 3-D laser scanner on a support base. The method further includes the steps of acquiring a point cloud of a segment of the crane runway rail; converting the point cloud into a voxel data structure; obtaining a cross section of the crane runway rail; obtaining a cross section of a reference rail from a reference rail voxel data structure; performing a fast-Fourier transform (FFT) image matching between the voxel data structure and the reference rail voxel data structure; and determining the deviation between the cross section of the crane runway rail and the reference rail cross section, wherein when the deviation exceeds a pre-determined threshold the runway rails are not aligned, and wherein when the deviation is at or below the pre-determined threshold the runway rails are aligned.

It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the disclosure.

