Bridge drive diagnostic system

Abstract

A diagnostic system for determining the existence of bridge tracking problems related to a relative difference of drive speeds of independent bridge drive motors on a crane. The diagnostic system includes at least one drive speed measurement unit (e.g., tachometer) that is utilized to measure the drive speed of each of the independent bridge drive motors on the crane. Generally, each drive speed is measured from the drive shaft and/or the drive wheel. The measured drive speeds are compared to determine if the relative difference is great enough to cause bridge tracking problems. The diagnostic system is portable and therefore usable on a plurality of cranes.

What is claimed is:  
     
         1 . A method of diagnosing bridge tracking problems related to a relative difference of drive speeds of independent bridge drive motors on a crane, the method comprising the acts of: 
 measuring the drive speeds of at least two independent bridge drive motors on the crane;    comparing the measured drive speeds;    determining the relative difference of the drive speeds of the at least two independent bridge drive motors; and    assessing if the relative difference of the drive speeds is the cause of the bridge tracking problems.    
     
     
         2 . A method as set forth in  claim 1 , and further comprising the act of coupling a drive speed measurement unit to at least one of a drive shaft and a driven wheel driven by one of the independent bridge drive motors on the crane, wherein the drive speed measurement unit is used to accomplish the act of directly measuring the drive speeds.  
     
     
         3 . A method as set forth in  claim 2  wherein coupling a drive speed measurement unit includes coupling a tachometer to at least one of a drive shaft and a driven wheel driven by one of the independent bridge drive motors on the crane.  
     
     
         4 . A method as set forth in  claim 3  wherein coupling a tachometer includes coupling a hand held tachometer to at least one of a drive shaft and a driven wheel driven by one of the independent bridge drive motors on the crane.  
     
     
         5 . A method as set forth in  claim 2  wherein the act of coupling the drive speed measurement unit includes at least one of electrically coupling, mechanically coupling, and optically coupling the drive speed measurement unit to the at least one of a drive shaft and a driven wheel driven by the one of the independent bridge drive motors on the crane.  
     
     
         6 . A method as set forth in  claim 2 , and further comprising the act of uncoupling the drive speed measurement unit from the at least one of the drive shaft and the driven wheel driven by the one of the independent drive motors of the crane after the act of measuring the drive speeds.  
     
     
         7 . A method as set forth in  claim 2 , and further comprising the act of coupling the drive speed measurement unit to a data acquisition unit.  
     
     
         8 . A method as set forth in  claim 7 , and further comprising the act of recording the measured drive speeds, wherein the data acquisition unit is used to accomplish the act of recording the measured drive speeds.  
     
     
         9 . A method as set forth in  claim 8 , and further comprising the act of displaying and analyzing the measured drive speeds that are recorded.  
     
     
         10 . A method as set forth in  claim 7  wherein the drive speed measurement unit and the data acquisition unit are portable.  
     
     
         11 . A method as set forth in  claim 1 , and further comprising the act of displaying the measured drive speeds.  
     
     
         12 . A method as set forth in  claim 1  wherein the act of measuring the drive speeds is done substantially simultaneously.  
     
     
         13 . A method as set forth in  claim 1  wherein the act of measuring the drive speeds includes directly measuring the drive speeds.  
     
     
         14 . A portable bridge drive diagnostic system for a crane, wherein the crane includes at least two independent bridge drive motors, the diagnostic system comprising: 
 at least one drive speed measurement unit, wherein the at least one drive speed measurement unit is configured to be coupled to at least one of a drive shaft and a driven wheel driven by one of the at least two independent bridge drive motors on the crane, and wherein the at least one drive speed measurement unit is operable to produce an output signal; and    a data acquisition unit configured to receive the output signal of the at least one drive speed measurement unit.    
     
     
         15 . A diagnostic system as set forth in  claim 14  wherein the drive speed measurement unit is a tachometer.  
     
     
         16 . A diagnostic system as set forth in  claim 15  wherein the tachometer is hand-held.  
     
     
         17 . A diagnostic system as set forth in  claim 14  wherein the at least one drive speed measurement unit is configured to be electrically coupled to at least one of a drive shaft and a driven wheel driven by one of the at least two independent bridge drive motors on the crane.  
     
     
         18 . A diagnostic system as set forth in  claim 14  wherein the at least one drive speed measurement unit is configured to be mechanically coupled to at least one of a drive shaft and a driven wheel driven by one of the at least two independent bridge drive motors on the crane.  
     
     
         19 . A diagnostic system as set forth in  claim 14  wherein the at least one drive speed measurement unit is configured to be optically coupled to at least one of a drive shaft and a driven wheel driven by one of the at least two independent bridge drive motors on the crane.  
     
     
         20 . A method of servicing a crane that is experiencing bridge tracking problems which may be related to a relative difference of drive speeds of independent bridge drive motors on the crane, the method comprising the acts of: 
 coupling portable drive speed measurement units to at least one of a drive shaft and a driven wheel driven by each one of the independent bridge drive motors on the crane;    measuring the drive speeds of at least two independent bridge drive motors on the crane in a substantially simultaneous manner, wherein the portable drive speed measurement units are used to accomplish the act of measuring the drive speeds;    coupling each of the drive speed measurement units to a data acquisition unit;    recording the measured drive speeds, wherein the data acquisition unit is used to accomplish the act of recording the measured drive speeds;    comparing the measured drive speeds;    determining the relative difference of the drive speeds of the at least two independent bridge drive motors;    assessing if the relative difference of the drive speeds is the cause of the bridge tracking problems; and    uncoupling the drive speed measurement units from the at least one of the drive shaft and the driven wheel driven by the each one of the independent drive motors of the crane after the act of measuring the drive speeds.    
     
     
         21 . A method as set forth in  claim 20  wherein coupling a drive speed measurement unit includes coupling a tachometer to at least one of a drive shaft and a driven wheel driven by one of the independent bridge drive motors on the crane.  
     
     
         22 . A method as set forth in  claim 21  wherein coupling a tachometer includes coupling a hand held tachometer to at least one of a drive shaft and a driven wheel driven by one of the independent bridge drive motors on the crane.  
     
     
         23 . A method as set forth in  claim 20  wherein the act of coupling the drive speed measurement unit includes at least one of electrically coupling, mechanically coupling, and optically coupling the drive speed measurement unit to the at least one of the drive shaft and the driven wheel driven by the one of the independent bridge drive motors on the crane.  
     
     
         24 . A method as set forth in  claim 10  wherein the act of measuring the drive speeds includes directly measuring the drive speeds.