INTERNATIONAL
ANDSPECIALIZED TRANSPORT
■
APRIL 2015
25
TOWER CRANES
the1,250 tonne-metre class, spaceunder
the foldableA-frame is limited, especially
whena largeprimemover (diesel hydraulic
drive) isused.Onahigh capacity crane
itmightmeannot leaving space for two
strongdiagonals leading from theboom
stoppoint of theA-frame to themachinery
deck. Evenwhen theA-frame strut in this
case is reinforced, it isobvious that in cases
of highwindpressure a long jib in steep
out of servicepositionwill not beheldby
theboom stops, butwill destroy thewhole
A-frame if itmovesbackwards.
Toprevent thisChinese crane
manufacturersYongmaoandZS relocate
the space-consumingdiesel engine inside
themachinerydeck framework so that
just thewinchunitshave to fit under the
A-frame. It avoids spaceproblems and
reducesnoisebut potential foroverheating
must be considered.At least theoil cooler
should remainabove themachinery
deck.Wolff gained experienceplacing
thehoistingwinchon topof the jibbase
sectiononmedium capacity luffers.
In the author’sopinion this couldalso
be considered for larger cranes,moving
thehoistingwinchand runnerwinch inside
thewide jib foot sectionas found
onLiebherr andNOV latticeboomoffshore
pedestal cranes.
In thisway spaceunder theA-frame
couldbegiven toawalk in electric
cabinet or sound-proofeddiesel hydraulic
container. Lackof spaceputs the third
winch for a light load runnerhoist on
traditional FavelleFavco craneson top
of thediesel hydraulicunit. Yongmao
relocated thiswinch into theA-framenear
thepart reinforced for theboom stops.
At first glance self containeddiesel
hydraulicdrives appear suitable for cranes
workingwithhigh linepull on the tallest
buildings. Problems remainwithoil
spoilingduringoperation, less acceptance
fromamore environmentally sensitive
construction industryand lower energy
efficiency. FavelleFavco in co-operation
with sister companyKrøll, plusmost
Chinesemanufacturersusing theoriginal
Favcodesign, offer electricallydrivenor
diesel hydraulicversions.
Bigwinches
FavelleFavco is apioneerof high capacity
winches for liftsof 25or 50 tonnesof
steelwork in single fall operation. Lifting
the100 tonne columns at thebaseof the
tallest high-rises requires just two fallsof
rope. Fewer turningpoints in the rope run
lengthens rope life and reduces friction.
Thebestway todo this is to feed just the
boomhead sheavesdirectly from the
hoistingwinch.At a lowboomangle the
heavyhoist ropedragsover the top surface
of theboomunless it isplacedhigher.
Liebherr’snew710HC-Lhas adouble
deckarrangementwith thewinchand two
hoistingdriveson the topand the electrical
cabinet underneath.
In1982Peiner introducedakindof
second level on theSN500, SN630and
SN1000modelswithonly7.50m tail
radius. Tricky riggingof theA-frame,
however, togetherwith thehoisting
winchplatformwas time consuming.
SYM experimented in2001withanother
two-level design.On theS480LH24 the
electrical cabinet and resistor switchboards
were inside a lattice framework.All the
wincheswereon topof theA-frame.
While the commonFavelleFavco split
deckdesigngives a rigidandversatile low
costmachinerydeck thequestion remains
how to connect the slewing frame to the
machinerydeck.Component size for
transport andweight for erectionmeans
that on large cranes the slewing ringhas to
bedisconnected from the frontmachinery
deck section. It involves removal of a large
numberof screws.On itsnewFHTD
product linemanufacturerFinehope avoids
this time consumingworkby connecting
themachinerydeckwith four largepins to
the slewingunit.
Anotherway to reduce theweight of the
individualmachinerydeck components
was first developedbyWolff for the355B
to1250B range.Now thisdesign is found
On theall-newYongmaoSTL1460C itspower
pack is alsomovedunder thedeck. In front of
the luffingwinch frame theengineexhaust and
air filter protrude through themachinery deck
LiebherrBos offshore cranes could show
theway for luffing jib tower cranedesign
concerning space savinghoistwinch installation
inside theboom foot sectionandE-Container or
Power packunder theA-frame
Yongmao relocated the runnerwinchon the
newSTL14060C into theA-frame front legs
above the largediameter hoistingwinch
While theelectrical cabinet and the resistor
switchboards are inside the lattice framework
of theS480LH24designedbySYM, thewinches
findaplaceon top
Slewing ring support and the front part
of theXGTL1600machinery platformmust
bedisconnectedby the slewing ringbolts
for transport
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