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*                          INFORMATION ALERT                        *  
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*  Produced by:  New Brunswick Occupational Health                  *  
*                and Safety Commission                              *  
*  Provided by:  Canadian Centre for Occupational Health and Safety *  
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INFO ALERT:  21 (NB)  
  
DATE:  June 1988  
  
  
*** HAZARD SUMMARY:  FALLING 800 LB BLOCK JUST MISSES WORKER  ***  
  
  The wire rope holding the hook block of a 20-ton overhead travelling  
  crane broke, causing the hook block to fall 20 feet to the ground.  
  It landed less than an arms length away from the worker operating  
  the crane.  
  
  The wire rope broke because the hook block had been pulled up  
  beyond the upper limit switch, bringing it tight to the drum.  The  
  torque of the drum motor was powerful enough to snap the wire rope.  
  
  Subsequent examination discovered that there were bent parts in the  
  trip lever mechanism.  Because of this, the trip lever failed to  
  activate the upper limit switch.  Regular routine inspections did not  
  detect the faulty trip lever mechanism.  
  
  
*** APPLICABLE SECTION(S) OF INDUSTRIAL REGULATIONS ***  
  
  1.  All workers are to be trained to recognize and avoid the hazards  
      associated with their work.  (Subsection 9(2)(b), OHSC Act)  
  
  2.  Ensure that cranes are propely maintained and regularly  
      inspected.  (Part 22(1)(b) and 22(10) Regulation 77-1)  
  
  3.  Crane operators should verify that the safety devices are working  
      prior to each use.  (Part 22(1)(c) Regulation 77-1)  
  
  4.  An upper limit switch shall be set so that it will open the  
      circuit to the hoist motor before the hook block reaches its upper  
      limit as specified by the manufacturer.  
  
  
  
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