Page 60 - Wire Rope News & Sling Technology - August 2019
P. 60

Inventor’s


                      Corner



                        By William Fischer


         Summer is in full swing. Construction is
         picking up, and the industry is leading the
         way. As always, we hope that our readers
         are prospering during the peak building
         season, and that all our readers, their friends
         and families are having a great summer.
         Thank you for your interest in Wire Rope
         News, and especially this Inventor’s Corner.



         Mobile crane
         Pat. 10,287,145 U.S. class B66C 23/74 Int. class B66C 13/20
         Inventor: Takahiro Iwazawa, Hyogo, JP.
         Assignee: KOBELCO CONSTRUCTION MECHINERY CO.,
         LTD., Hiroshima-shi, JP.
           This patent presents a mobile crane including a crane main
         body and a control valve which controls a supply flow rate of
         hydraulic oil to a main-body driving motor and a pilot-pres-
         sure control device which controls a pilot pressure supplied to
         the control valve. The pilot-pressure control device increases
         the pilot pressure at a first ratio according to an increase in
         an operation amount of an operation section when a counter-  Figure 2: Schematic side view of the mobile crane  and a diagram
         weight carrier is an uncoupled state, increases the pilot pres-  showing a state in which the counterweight carrier is in the coupled
         sure at a second ratio lower than the first ratio according to   state and an afloat state.
         the increase in the operation amount when the counterweight   The crane 2 according to this embodiment is configured to
         carrier is a coupled state and a grounded state, and increases   take a coupled state (see figures 1 and 2) and an uncoupled
         the pilot pressure at a third ratio higher than the second ratio   state (see figure 3). The coupled state of the crane 2 is a state
         and equal to or lower than the first ratio according to the in-  in which the carrier 4 is coupled to an upper swing body 7
         crease in the operation amount when the counterweight car-  of the crane main body 3 via the coupling beam 5. The un-
         rier is the coupled state and an afloat state.       coupled state of the crane 2 is a state in which the carrier 4
           The crane  2 according to this embodiment includes,  as   is disconnected from the upper swing body 7 and the crane
         shown in figure 1, a crane main body 3 configured to be ca-  main body 3 stands alone.
         pable of self-traveling and perform crane work, a counter-  The crane main body 3 includes a lower traveling body 6,
         weight carrier 4 for increasing stability of the crane main   the upper swing body 7, a swing-body driving device 8 (see
         body 3 to improve a hoisting ability, and a coupling beam   figure 4), a traveling operation device 9, a swing operation
         5 that alternately couples the crane main body 3 and the   device  10, an engine  12, a number-of-revolutions  detect-
         counterweight  carrier  4.  In  the  following  explanation,  the   ing  section  13,  a hydraulic  pump  14  (see  figure  5),  and  a
         counterweight carrier 4 is simply referred to as carrier 4.   discharge-flow-rate changing device 15. The lower traveling
                                                              body 6 is a crawler type and is configured to be capable of
                                                              self-traveling. The lower traveling body 6 includes a pair of
                                                              crawler devices 20 disposed to be separated into both side
                                                              portions (left and right both side portions) in a vehicle width
                                                              direction of the lower traveling body 6. The crawler devices
                                                              20 include not-shown driving devices including not-shown
                                                              hydraulic motors, not-shown control valves, and not-shown
                                                              switching  valves.  The  configuration  of  the  driving  devices
                                                              is the same as the configuration of the swing-body driving
                                                              device  8 explained below.  The  hydraulic  motors generate
                                                              power by being supplied hydraulic oil to the hydraulic mo-
                                                              tors of the crawler devices 20. Whereby the crawler devices
                                                              20 operate to cause the lower traveling body 6 to self-travel.
                                                               The engine 12 (see figure 4), the number-of-revolutions de-
         Figure 1:  Schematic side  view of a mobile crane and a diagram
         showing a state in which a counterweight carrier is in a coupled state   tecting section 13, the hydraulic pump 14 (see figure 5), and
         and a grounded state.                                the discharge-flow-rate changing device 15 are mounted on
         60     Wire Rope News & Sling Technology   August 2019
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