42042 B model Tower Crane with MOD

[doug72]

My version of the 42042 B model Lego Tower Crawler Crane built from parts I had available.

Had to use an old type turntable (so only manual rotation at present) - waiting for a new Z60 turntable (on order) to allow power rotation.

Have modified it to have power traverse for the hoist trolley along the beam.

The drive unit is located at base of the tower and driven by same drive as the hoist drum. It was a tight squeeze to fit the gears and change over clutch- hence gears outside the frame work.

the drive shaft to the traversing drum runs up the side of the tower.

It took a lot of experimenting to get the hoist trolley to move smoothly.

Eventually found that if ropes wound on more than one layer then ropes either went slack or too tight.

The traversing ropes use a double drum with two ropes coming off the top and bottom.

i.e. as one rope winds in the other pays out.

For the drums I use 2 x 2 round plates - 2 & 3 deep with large wedge wheels as end and center plates.

This meant ropes were only one layer deep when trolley reached either end stops.

The rope for pulling trolley towards the rope drums has a tension spring to keep the ropes tight and also allows for over winding when hits the end of its travel.

Drum drive also protected by a 16T clutch gear,

see photos on post # 4 & 5

https://www.flickr.c...157655615704354

Edited August 30, 2015 by Doug72

[Kiwi_Builder]

It's a nice modification but you would get more feedback if you add photos to your post, otherwise people will just leave because there are no photos right there.

[Edwin Korstanje]

Just like this .

[doug72]

Thanks for the advice wondered why no comments.

I thought I had by including the Flika link - have now used the shared option to load photos one by one.

Assume it is possible to do the same with an album on Flicka.

Doug

IMG_2494 by Doug Ridgway,

on Flickr

IMG_2493 by Doug Ridgway, on Flickr

IMG_2496 by Doug Ridgway, on Flickr

IMG_2495 by Doug Ridgway, on Flickr

IMG_2497 by Doug Ridgway, on Flickr

IMG_2498 by Doug Ridgway, on Flickr

IMG_2499 by Doug Ridgway, on Flickr

IMG_2492 by Doug Ridgway, on Flickr

Edited August 30, 2015 by Doug72

[Cumulonimbus]

Hi Doug72,

Nice MOD. The 42042B has inspired me to design and build a MOC tower crane. Here, I have run into the same issue as you, when using two spools for the traversing movement the difference in diameter between the two will cause one of the threads to sag. I'm thinking it could be solved by using one continuous string connected to a drum at each end and a pulley which keeps the sting under tension with a spring. I have to test it yet, but I don't have time for it now.

[doug72]

Thanks Cumulonimbus,

I have modified the trolley haulage drum to single wide drum without centre divider as found ropes were winding on & off OK as ropes run up each side of the boom to the trolley.

The haul in rope is connected via a tension spring at the trolley. The haul out rope is secured by a black pin with the rope in the small slot - by turning this pin you can adjust the tension in the system and when OK secure the end to another pin on the trolley.

Due to the Lego design the trolley sometimes sticks due to friction or catches on the centre beams.

For my Giant block Setting Crane I used a different method of moving the hoist trolley.: http://www.eurobrick...showtopic=91929

The trolley runs on small wheels along a double rail track along the top of the boom.

The drive to the rope cord is via 32mm diam pulley with rope in contact for 270 degs.

When trolley reaches its end stops the rope just slips on the pulley but is also protected by a 16T clutch gear

Tension in the rope is adjusted at the hoist trolley by a rotating pin w/cross axle which then locked by means of a thin 3L plate w/axle hole.

Click image to see video.

MVI_0748 by Doug Ridgway, on Flickr

I have also used braided rubber cord and a friction pulley to traverse a hoist trolley on a container crane I built for my lego rail layout with success - rubber cord can be obtained from craft shops or on line.

Edited August 31, 2015 by Doug72