Page 12 - Wire Rope News & Sling Technology
P. 12

back on and checked. After one use, the
                                                                               rope already showed  crushing  dam-
                                                                               age. This required a call to the manu-
                                                                               facturer  to consult  as  to “Why?”  this
                                                                               would he happening. The size and type
                                                                               of wire rope was verified for the crane
                                                                               and the manufacturer suggested that
                                                                               the  crushing  was  due  to  overuse  and
                                                                               wear, but this was not the case as the
                                                                               rope had just been installed.
                                                                                 The “Why?” needed even further in-
                                                                               vestigation. It was  clear  by the dam-
                                                                               age that the wire rope was not laying
                                                                               properly in the grooves created by the
                                                                               preceding layers. This  required closer
                                                                               inspection of the crossover  point. On
                                                                               this  crane,  the  drum  had a tapered
                                                                               transition manufactured into the drum
                                                                               to help the wire rope spool properly. Af-
                                                                               ter a detailed inspection and additional
                                                                               conversations with the crane manufac-
                                                                               turer, they determined that the drum
                                                                               had a manufacturing defect causing it
                                                                               to pinch the wire rope and not transi-
                                                                               tion the layers properly. The  drum
                                                                               was replaced, the crane received a new
                                                                               hoist rope and the crane was safe for
                                                                               operation again.  While  manufacturer
                                                                               defects are not very common, this ex-
                                                                               ample demonstrates the importance of
                                                                               not giving up on asking “Why?” until a
                         Wire  rope not spooling  properly on  a crane’s       true resolution is found.
                         drum is usually an easy fix when caught early.        Training as a Factor
                         This photo shows rope that is probably crushed          In  the  absence  of  formal  training,
                         and damaged beyond use.
                                                                               workers often do whatever they need to
                                                                                                continued on page 14
         continued from page 10
         be visually inspected daily as part of     Mobile Crane Periodic Wire Rope Inspection
         the  operator’s  pre-use  checklist.  Then                    Tips for Safety
         when spooling issues are detected they
         can usually be remedied by running as   When it inspecting wire rope on a   rope—only half the rope can be seen
         much wire rope off the drum as possi-  mobile crane,  there are several key   at any given time, so feel is critical to
         ble (leaving the minimum wraps on the   tips to help keep the inspector and   the inspection.
         drum)  then  re-spooling  the  wire  rope   operator safe:              7. The crane operator NEVER
         making sure  it winds  nice  and tight   1. The crane operator and inspector   spools  rope  off  the  drum  until  they
         with no gaps between the wraps and a   must start with a meeting to discuss   clearly understand the inspector’s
         smooth cross over between layers.    each  person’s  role  and how  the  in-  instruction to do so. A suggested
           If loose and uneven spooling is not ad-  spection will be preformed—it helps   method would be having the operator
         dressed quickly, it can and usually does   if the crane operator knows what the   adjust the rear facing mirror to see
         create excessive wear, crushing and dis-  inspector will be doing.    the inspector—and the drum does not
         tortion of the wire rope. The results of   2. The inspector must NEVER   move on verbal command alone, but
         such abuse are a reduction in the wire   stand next to the crane drum when   they must see the inspector’s hands
         rope’s  effective  strength  and  a  shorter   the crane’s house lock is not engaged.  held up and away from the drum.
         service life. So asking “Why?” can not   3.  The  inspector  must  NEVER  in-  8.  If  direct  visual  communication
         only extend the life of the wire rope but   spect wire rope as it is coming onto a   cannot be maintained a signal per-
         lead to safer operations as well.    drum—the rope should be inspected   son should be used.
           In the case of the mobile crane  pic-  as is it is being spooled off the drum.   9. The operator should understand
         tured on the cover, the crane was hav-  4. The inspector must have fall   that some areas of the rope inspec-
         ing issues with the wire rope showing   protection so both hands can be used   tion  take longer  than  others—at
         evidence of crushing  but the owners   during the inspection.         times there may be longer or shorter
         could not figure out the “Why?”. They   5. The wire  rope is  never  spooled   delays between spooling commands.
         called in Crane Tech to help determine   more than about 36-inches at a time.   10. Absolute safety must be main-
         the cause.  A new  hoist  rope was  in-  This allows the inspector to reach   tained at all times—any misunder-
         stalled on the crane and the boom was   each section of rope for inspection.   standing of a command from the in-
         raised to 60-degrees, allowing the wire   6. The inspector must wear protec-  spector must be met by not moving
         rope to be spooled off and then spooled   tive gloves that allow for feel of the   the drum.

         12     Wire Rope News & Sling Technology   June 2017
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