Jump to content


8421 Crane Boom issue


74 replies to this topic

#26 efferman

efferman

    Posts: 2984
    Joined: 03-May 10
    Member: 10499
    Country: Germany

Posted 18 November 2012 - 04:26 PM

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

Posted Image
100_9862 von efferman auf Flickr
not completely lego, but nearly invisible
need some vitamin ABS intravenously?
Volvo L350F replica
effe on shapeways.com

#27 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 18 November 2012 - 04:30 PM

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

Updated 02/08/12
Posted Image

#28 DLuders

DLuders

  • Technic Technician


    Posts: 5817
    Joined: 17-October 09
    Member: 7868
    Country: USA (WA State)

Posted 18 November 2012 - 04:30 PM

@ 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:

Posted Image

#29 DarkShadow73

DarkShadow73

    Posts: 635
    Joined: 06-October 10
    Member: 13640
    Country: USA

Posted 20 November 2012 - 05:03 PM

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 :wink: )

#30 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 26 November 2012 - 01:40 AM

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. :tongue:

Edited by Alasdair Ryan, 26 November 2012 - 01:41 AM.

Posted Image

Updated 02/08/12
Posted Image

#31 skylinedan

skylinedan

    Posts: 268
    Joined: 04-March 12
    Member: 27106
    Country: USA

Posted 26 November 2012 - 02:04 AM

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.

#32 DLuders

DLuders

  • Technic Technician


    Posts: 5817
    Joined: 17-October 09
    Member: 7868
    Country: USA (WA State)

Posted 26 November 2012 - 02:19 AM

View PostAlasdair Ryan, on 26 November 2012 - 01:40 AM, said:

Attention Dluders' vote does not apply. :tongue:

Posted Image

#33 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 26 November 2012 - 09:39 PM

It still needs improvement.......

Posted Image
Posted Image

Updated 02/08/12
Posted Image

#34 DLuders

DLuders

  • Technic Technician


    Posts: 5817
    Joined: 17-October 09
    Member: 7868
    Country: USA (WA State)

Posted 27 November 2012 - 02:10 AM

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

#35 DarkShadow73

DarkShadow73

    Posts: 635
    Joined: 06-October 10
    Member: 13640
    Country: USA

Posted 27 November 2012 - 03:35 PM

View PostAlasdair Ryan, on 26 November 2012 - 01:40 AM, said:

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. :tongue:

@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

View PostDLuders, on 27 November 2012 - 02:10 AM, said:

I like the motorized Linear Actuators instead of using pneumatic cylinders, since LAs will keep the Grove boom extended.  :classic:   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

View PostAlasdair Ryan, on 26 November 2012 - 09:39 PM, said:

It still needs improvement.......

Posted Image

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

View Postskylinedan, on 26 November 2012 - 02:04 AM, said:

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...

#36 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 27 November 2012 - 04:37 PM

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. :blush:

Poll

Edited by Alasdair Ryan, 27 November 2012 - 04:59 PM.

Posted Image

Updated 02/08/12
Posted Image

#37 Technic Gearhead

Technic Gearhead

    Posts: 315
    Joined: 28-January 12
    Member: 25113
    Country: United States

Posted 27 November 2012 - 05:04 PM

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.

#38 allanp

allanp

    Posts: 1983
    Joined: 15-September 06
    Member: 961
    Country: UK

Posted 27 November 2012 - 07:14 PM

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?! :wink:
Even the best can be made better, but most important is to be excellent to each other and party on dudes!!!!!!

#39 1974

1974

    Posts: 815
    Joined: 10-August 11
    Member: 19654
    Country: LEGOland

Posted 27 November 2012 - 07:23 PM

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

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

#40 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 27 November 2012 - 08:02 PM

View Postallanp, on 27 November 2012 - 07:14 PM, said:

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?! :wink:

You...... :roflmao:
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 by Alasdair Ryan, 28 November 2012 - 02:10 AM.

Posted Image

Updated 02/08/12
Posted Image

#41 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 28 November 2012 - 02:08 AM

We have a update.....

Posted ImagePosted Image

View Post1974, on 27 November 2012 - 07:23 PM, said:

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

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

Edited by Alasdair Ryan, 28 November 2012 - 02:10 AM.

Posted Image

Updated 02/08/12
Posted Image

#42 Technic Gearhead

Technic Gearhead

    Posts: 315
    Joined: 28-January 12
    Member: 25113
    Country: United States

Posted 28 November 2012 - 02:30 PM

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

#43 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 28 November 2012 - 02:44 PM

I plan to post more progress latter tonight. :wink:
Posted Image

Updated 02/08/12
Posted Image

#44 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 29 November 2012 - 01:00 AM

Tonight's progress.

Posted Image
Posted Image

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

Updated 02/08/12
Posted Image

#45 DarkShadow73

DarkShadow73

    Posts: 635
    Joined: 06-October 10
    Member: 13640
    Country: USA

Posted 29 November 2012 - 03:18 AM

@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...

#46 Technic Gearhead

Technic Gearhead

    Posts: 315
    Joined: 28-January 12
    Member: 25113
    Country: United States

Posted 29 November 2012 - 04:11 AM

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!

#47 phool

phool

    Posts: 115
    Joined: 12-March 10
    Member: 9889
    Country: South Africa

Posted 29 November 2012 - 01:44 PM

View PostLost_In_Noise, on 17 November 2012 - 10:39 PM, said:

Why don't you write a book?

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

#48 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 29 November 2012 - 02:31 PM

View PostTechnic Gearhead, on 29 November 2012 - 04:11 AM, said:

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

You can look forward to a update tonight. :sweet:

Edited by Alasdair Ryan, 29 November 2012 - 02:32 PM.

Posted Image

Updated 02/08/12
Posted Image

#49 Technic Gearhead

Technic Gearhead

    Posts: 315
    Joined: 28-January 12
    Member: 25113
    Country: United States

Posted 29 November 2012 - 02:40 PM

Excellent - bonus functions too!!  :thumbup:

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.

#50 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 29 November 2012 - 03:35 PM

View PostTechnic Gearhead, on 29 November 2012 - 02:40 PM, said:


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.
Posted Image

Updated 02/08/12
Posted Image



Reply to this topic



  


0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users