Page 71 - Wire Rope News & Sling Technology - October2019
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Denny’s                                        Cranes and Planes,
         crane and                                    Automatic Controls!
                                                        Common Ground –
         rigging notes

                                                                 by Dennis J. O’Rourke, CSP

            ome time  ago, during  a deposition,  I made a compari-  with the gravitational pull of the earth.
          Sson between a Crane and a Plane regarding operating   A crane itself doesn’t become airborne (hopefully), but the
          and instructions to the operator/pilot. There are times when   load on  the hook  does. And when  it does the structure  of
          those who control these machines have to make critical deci-  the boom can flex up to 20’, thus, increasing the operating
          sions, and both of the devices contend with Gravity. A re-  radius overloading the crane. Some manufacturers install
          buttal expert witness said he saw no comparison between   computers to automatically “Boom-up” to maintain the cor-
          planes and cranes, he (in my opinion) was wrong!    rect operating radius. And, engine torque is pulling the load
           My analogy between the two machines was that important   from the earth’s gravity.
          information for flying a plane was easily reviewed by the pi-  Programming automatic controls  in modern planes and
          lot while setting in his seat, the charts, and manuals are in   cranes, how is that done and more importantly, how do we
          front of them. The crane operator, in my example, needed to   verify that they are working properly? Well, this is where
          stand up, walk back, and read the tiny printed instructions   I discuss only cranes and leave the planes to the Aircraft
          riveted to a dark inside wall of the machinery house (P&H   manufactures to figure out.
          9125 Truck crane).                                   As I see it, two methods are now in use “crane input or
           At the time of my depo, the crane configurations were not   operator input.” First, crane input, there are mechanical
          as complex (number of accessories) as nowadays, and capac-  sensors built in the crane that when energized, communi-
          ity charts/notes could be “properly” placed in cabs visible to   cate to the computer as to how the crane is configured or put
          operators. As for a small plane, a 10 point placard to review   together, affecting the capacity. Operator input-errors can
          at take-off would suffice – not today.              be: load weight, radius, parts of rope, length of luffing jib,
           How do planes react to some elements such  as loading,   outrigger/crawler extension, amount/extension of the coun-
          structural fatigue, gravity, and pilot errors? Just as a crane   terweight, luffer mast off-set angle, angle of the live mast to
          operator must react to these same topics in the 21st century,   boom angles limiting capacity, boom length, which hoist is
          the second-decade era of technology. We are attempting to   used, and much more depending on the crane, more acces-
          removing or “engineer out, human error” accidents involving   sories, more chance for – operator error.
          these machines.
           When a plane is heading down the runway to achieve flight
          speed, the pilot holds the nose down till airspeed is reached.
          He then raises the nose and becomes airborne. After lift-off,
          he lowers the nose to maintain airspeed by reducing drag,
          due to the take-off wing angle. Errors can be made during
          this critical take-off maneuver. So, a computerized back-up
          control system is installed to reduce the possibility of a pilot
          error – stalling the plane.                                                                           Photo courtesy of Dennis O’Rourke

                                                               Modern cranes cabs have changed. An owner or user of
                                                              such an automatically controlled crane must establish a test
         Photo © ssuaphoto | iStockphoto                      chines - planes, cranes, or even cars we wonder, how reli-
                                                              procedure to verify computer accuracy, which is usually be-
                                                              yond the standard Crane Certifier’s skills set.
                                                               As we  venture  into  the  era  of automatic operating ma-
                                                              able are these machines? And what are the consequences of
                                                              their “wrongness? Trustworthiness is established by design,
                                                              maintenance, and performance testing. We don’t need to
                                                              invent new methods for dependability. Elevators are auto-
                                                              matic machines with unmatched performance. The quality
                                                              and type of maintenance/testing on elevators are regulated
           When a plane is on the ground, the Fuselage is support-  by State licenses. Seems to be working. n
          ing the wings, when in the air the wings are holding up the
                                                               DENNIS J. O’ROURKE, CSP, is the Director of National Crane Services, Inc. He has over
          entire air-machine. This changing force direction causes the   fifty years’ experience in the industrial, maritime, and construction fields working with heavy
          wings to bend and flex (maybe 20 feet) that causes fatigue.   equipment and material handling devices. As a safety engineer, Mr. O’Rourke has developed
          The engine thrust creating this lift is in a continual battle   and/or presented over 300 safety-training programs for all representative elements of govern-
                                                              ment and industry.
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