8421 Crane Boom issue

[efferman]

i have an other idea. maybe you can use a transparent hose with a inner diameter of the outer cylinder rod diameter. cut the hose lengthwise on one side and push it over the rod

100_9862 von efferman auf Flickr

not completely lego, but nearly invisible

[Alasdair Ryan]

Could you make some sort of ratchet in order to keep the boom up?

[DLuders]

@ efferman: I like your solution. If the "Lego Purists" out there want to use 100% Lego pieces, maybe one could slit a black 7mm Flexible Hose:

[DarkShadow73]

I'm thinking of going simplistic on this one and just adding beams as posted by Blakbird to hold the crane's boom in an upright position as it will be a display model (although I want to play with it from time to time )

[Alasdair Ryan]

I have rebuilt my upper part of the crane and I am currently exploring ideas on how to keep the boom in the air and not fall to the ground.

May I ask for a show of hands (or in this case a 'yes I want one' or 'no,go mess around with something else) for a motorized arm instead of the pneumatic cylinders?

Attention Dluder's vote does not apply.

Edited November 26, 2012 by Alasdair Ryan

[skylinedan]

I,m working on a Grove right now and I,m thinking the same idea for a way to raise the boom. Not all that happy with the way the 8421 works.

[DLuders]

Attention Dluders' vote does not apply.

[Alasdair Ryan]

It still needs improvement.......

[DLuders]

I like the motorized Linear Actuators instead of using pneumatic cylinders, since LAs will keep the Grove boom extended. Pneumatics leak air, and the boom eventually eases back down on its own.

[DarkShadow73]

I have rebuilt my upper part of the crane and I am currently exploring ideas on how to keep the boom in the air and not fall to the ground.

May I ask for a show of hands (or in this case a 'yes I want one' or 'no,go mess around with something else) for a motorized arm instead of the pneumatic cylinders?

Attention Dluder's vote does not apply.

@Alasdair - you have my vote for sure...I've often thought about adding an LA to each side of the boom, but since this model was released in 05 with the previous battery box and motor, not sure how to go about it with PF elements...if you come up with a new idea..please let it be known...

Thanks, Eric

I like the motorized Linear Actuators instead of using pneumatic cylinders, since LAs will keep the Grove boom extended. Pneumatics leak air, and the boom eventually eases back down on its own.

@DLuders - never would have thought pneumatics would be that weak since I really jam on the hoses to the hilt at all connections

It still needs improvement.......

@Alasdair - guess I should look down the reply list before posting, that looks like a great start...

I,m working on a Grove right now and I,m thinking the same idea for a way to raise the boom. Not all that happy with the way the 8421 works.

@skylinedan - hey bud - yeah I hate that I raise it at night, then in the morning the boom is lying flat down and string and all just a mess...if I can't get an LA to work like Alasdair is working on I might just go with the support beams to keep it up, then pump the system with air and remove the beams and retract/let it down...the model is brilliant, but that one quirk about it kind of ruins the fun of keeping boom up for more than a few hours...

[Alasdair Ryan]

Great so I have two votes,please keep them coming as I don't want to waste my time working on something for the forum if nobody wants it.

Poll

Edited November 27, 2012 by Alasdair Ryan

[Technic Gearhead]

It looks like you're off to a good start! It would be nice to see it fully integrated with minimal impact to the original model. That's what I was going for with my modernized 8421 PF. My boom is still pneumatic for the sake of originality. I just display it in the down position for the same reasons mentioned here.

[allanp]

Alasdair I can see one problem with your design. I'll give you a clue, it's long, grey, requires thumbs of never ending endurance and generally crap! Can you guess what it is yet?!

[1974]

Really, you get a sore thumb by pusing that little green switch on that long, grey crappy batterybox?

Pneumatics are fun, but they suck at precise powerfull movements. Motors ftw!

[Alasdair Ryan]

Alasdair I can see one problem with your design. I'll give you a clue, it's long, grey, requires thumbs of never ending endurance and generally crap! Can you guess what it is yet?!

You......

I plan on making a whole new upper section with two separate gearboxes.There will also be something extra as well,that's if it all goes to plan.

Edited November 28, 2012 by Alasdair Ryan

[Alasdair Ryan]

We have a update.....

Really, you get a sore thumb by pusing that little green switch on that long, grey crappy batterybox?

If you are meaning the white gear that's on top of my rechargeable battery box, that is to control the speed.

Edited November 28, 2012 by Alasdair Ryan

[Technic Gearhead]

Progress! I like what you have so far - looking forward to seeing it when you're finished.

[Alasdair Ryan]

I plan to post more progress latter tonight.

[Alasdair Ryan]

Tonight's progress.

I plan to shorten the back a bit,once I get the motor hocked up I will start on the body work.

[DarkShadow73]

@Alasdair-

Looks like its going to be something that might need to be added to LDD...quite an assembly so far...you get two extra votes from me...

[Technic Gearhead]

It's coming along nicely. It looks pretty complex too. Are you going to use the original motor for all three of the functions? I assume that is the plan with your two gearboxes. It looks very well made also - looking forward to more updates!

[phool]

Why don't you write a book?

Cos' then we would have to ewait even longer for the next installment of technicopedia!

[Alasdair Ryan]

Are you going to use the original motor for all three of the functions?

Its got four functions as an extra thank you for building my Mod.

I will be making instructions so you don't need to worry.

You can look forward to a update tonight.

Edited November 29, 2012 by Alasdair Ryan

[Technic Gearhead]

Excellent - bonus functions too!!

Is the one LA going to be long enough for the full range of the boom? Visually that would look the best for sure, even if it didn't go quite as far up as the two pneumatic cylinders.

This is exciting! The 8421 is one of my favorites and I often wonder what it would have looked like if it was designed in the last few years with all of the current parts available.

[Alasdair Ryan]

Is the one LA going to be long enough for the full range of the boom?

I am hopeful it will be as close as possible,if not I would think about making a custom LA.