Page 62 - Wire Rope News & Sling Technology - February 2020
P. 62

INVENTOR’S CORNER
         continued from previous page




















                                                              Figure 7: Illustrates a detailed perspective view of the top end of the
                                                              pendant being connected to the suspension assembly segment.

                                                              front portion of the rotating bed 20; a live mast 28 mounted
                                                              at its first end on the rotating bed 20, boom hoist rigging
                                                              30 connected to the live mast 28 adjacent a second end of
                                                              the live mast 28; and a moveable counterweight unit 34. In
                                                              figure 5, the counterweight unit 34 has multiple stacks of
                                                              individual counterweight  members on a support member.
                                                              In other embodiments, the counterweight unit may have a
                                                              single counter weight.
                                                               Boom hoist rigging 30 between the top of the live mast 28
                                                              and the rotating bed is used to control the angle of the live
                                                              mast 28. A suspension assembly 36 between the top of the
                                                              live  mast  28  and  the  boom  22  supports  the  boom.  A  load
                                                              hoist line (not shown) is trained over a pulley on the boom
                                                              22, supporting a hook (not shown) at a first end. At a second
                                                              end, the load hoist line is wound on a first main load hoist
                                                              drum (not shown) connected to the rotating bed 20. The ro-
                                                              tating bed 20 includes other elements commonly found on
                                                              a mobile lift crane 10, such as an operator’s cab and a hoist
                                                              drum for the boom hoist rigging 30.
                                                               The boom hoist rigging 30 includes a boom hoist line in the
                                                              form of wire rope wound on a boom hoist drum, and reeved
         Figure 6: Illustrates a side view of an embodiment of a mobile lift   through sheaves on the live mast 28. The live mast 28 is con-
         crane having a fixed mast.                           nected to the rotating bed 20 though the boom hoist rigging
                                                              30 and to the boom through the suspension  assembly  36.
         create the longitudinal part of the crane suspension assem-  This arrangement allows rotation of the boom hoist drum
         bly, and are therefore crane suspension assembly sections.   to change the amount of boom hoist line between the live
         The sections  may be made of multiple parallel elongated   mast 28 and the rotating bed 20 changing the mast angle
         members. The term “crane suspension  assembly section”   and thereby changing the boom angle through the suspen-
         also includes the equalizer and the boom top, since these are   sion assembly 36.
         parts of the boom suspension assembly and are connected to   The boom  22 is made  by connecting multiple boom sec-
         boom backstay straps. “Crane suspension assembly section”   tions together and the boom 22 is supported during crane
         also includes other members attached to strap sections, such   operation by the suspension assembly 36 made from boom
         as the boom butt, the mast top, the jib top, jib strut tops and   strap sections. The top end of the suspension assembly 36 is
         live mast top, and intermediate suspension members.  connected to the top end of the boom 22 and an intermediate
           While the disclosed subject matter will have applicability   location of the suspension assembly 36 is connected to an
         to many types of cranes, they will be described in connection   intermediate location of the boom 22 through a pendant 38.
         with  a mobile lift crane  10,  shown  in  an operational con-
         figuration with a live mast in figure 5 and in an operational
         configuration with a fixed mast in figure 6. The mobile lift
         crane 10 includes lower works, also referred to as a carbody
         12, and moveable ground engaging members in the form of
         crawlers 14. Of course additional crawlers than those shown
         can be used, as well as other types of ground engaging mem-
         bers, such as tires.
           A rotating bed 20 is mounted to the carbody 12 with a slew-
         ing ring, such that the rotating bed 20 can swing about an
         axis with respect to the ground engaging members 14. The   Figure 8: Illustrates a side view of the boom insert showing a pendant
         rotating bed 20 supports a boom 22 pivotally mounted on a   connecting the boom insert and a suspension assembly segment.
         62     Wire Rope News & Sling Technology   February 2020
   57   58   59   60   61   62   63   64   65   66   67