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The mast and boom rotate on a vertical thrust bearing
consisting of a Meccano ball resting in a socket coupling. The side
bearing at the top of the tower consists of a wheel flange running
between plastic spacers. In the original model 0.5" plastic pulleys
were used but I found these gave two much slop, no doubt due to my
slight differences in construction from the original when building the
tower. I
repositioned the supporting rods and found that the plastic spacers
made a
perfect fit. The top part of the model can be seen in the
pictures above and below. The lower picture also shows the booms
sitting in the cradle I made to transport the model to
exhibitions. There are three motors used one for each of the
operations, slewing, hoisting and the trolley. I used two small French
Meccano 6 volt motors and a 12 volt Escap geared motor, for each of
these functions. The model uses a common earth wiring system
enabling just two wires to be threaded up through the thrust bearing.
The model is controlled by a 12 volt model railway controller and
on/off toggle switches mounted on the crane base. I made a few minor changes to Philip's original design.
I made use of the small push on
rubber stopper/pulley p/n 23c (a part not available in 1988) on the
drive shaft
for trolley cord rather than just wrapping the string around the
shaft. I found the original method tended to slip and bind.
I beefed up the trolley construction using flat girders. I found that I
needed extra weight on the pulley block and substituted plastic 0.5"
pulleys with brass ones. I did not have a" Meccano Space" clear canopy
so
I constructed the cab front using narrow strips and transparent plates.
Picture 3 shows a close up of the new control switches and the slewing
drive. The top picture shows three Liebheer tower cranes at a
construction site in Vancouver near Canada Place. The picture was taken
on August 30 2006. You can see how closely the model represents an
actual crane. I feel I must congratulate Philip on a very well thought out
and beautifully designed model. The plans to build this model are available from Meccano Worldwide Mail
Order ![]() December 15 2005 Revised September 4 2006 |
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