SNIPE Posted January 18, 2014 Posted January 18, 2014 HI How can I connect these three lift-arms in the middle by either the first or second hole? now the triangle shape is a perfect triangle unlike how it was a few days ago but I need to find something that lines up with how the holes are now. Regards, S Quote
Alasdair Ryan Posted January 18, 2014 Posted January 18, 2014 Lego make thin triangle shaped liftarms,try one of those or try the grey three pronged connector (used for attaching propeller blades). Quote
SNIPE Posted January 18, 2014 Author Posted January 18, 2014 Having something like this or something with the same pin/hole spacing does not work unfortunately my first model used a technic 0.5L thick pulley but that made the model taller than wider by a little bit. Quote
SNIPE Posted January 18, 2014 Author Posted January 18, 2014 (edited) Those don't work either as they are the same as the technic pulley, the three pictures abode line up the same as the pulley maybe I need to change the lift arms Edited January 18, 2014 by SNIPE Quote
jadedomg Posted January 18, 2014 Posted January 18, 2014 http://www.bricklink.com/catalogItem.asp?P=92338 You could try using the 5L chain with studs on the ends to keep them together, they will still have some play but they wont fall down towards the edge of the triangle Quote
NevynPA Posted January 20, 2014 Posted January 20, 2014 Portal axle hub? Pulley with holes? I don't know if the spacing on either of those matches, but it looks close? Quote
Hrafn Posted January 20, 2014 Posted January 20, 2014 HI How can I connect these three lift-arms in the middle by either the first or second hole? now the triangle shape is a perfect triangle unlike how it was a few days ago but I need to find something that lines up with how the holes are now. Regards, S What if instead of the T-liftarms, you used wedge belt wheels to connect the outer three liftarms? That might move the inner spokes towards the center just enough that they too could be joined by wedge belt wheels or other parts. Quote
Rockbrick Posted January 21, 2014 Posted January 21, 2014 would look like s**t but how about: + or Quote
SNIPE Posted January 21, 2014 Author Posted January 21, 2014 (edited) Not sure I understand, isnt that the same as this Edited January 21, 2014 by SNIPE Quote
Philo Posted January 22, 2014 Posted January 22, 2014 What about using Technic pulley this way? Granted, it is not centered, and end peg holes are not exactly one stud apart, so there is some part stress - I have not tried with physical parts... Quote
SNIPE Posted January 22, 2014 Author Posted January 22, 2014 Tthat is exactually how I had it prior, maybe I should stick with this and not have it centered perfectly. Quote
Philo Posted January 22, 2014 Posted January 22, 2014 Ah - sorry, looks like I missed a chapter in the story ;) Quote
Hrafn Posted January 22, 2014 Posted January 22, 2014 Would this work? I'd add at least 3 more friction pins (connecting the short liftarms to the pulley wheels / wedge belt wheels) but it's surprisingly strong in-plane as is. Quote
Erik Leppen Posted January 22, 2014 Posted January 22, 2014 If you replace one of the 9L liftarms by a 11L it's even stronger. Quote
SNIPE Posted January 23, 2014 Author Posted January 23, 2014 interesting idea here I think i'll use it. Quote
jorgeopesi Posted January 23, 2014 Posted January 23, 2014 It is nice to see Technic minds thinking together and reaching great solutions . Quote
Hrafn Posted January 23, 2014 Posted January 23, 2014 interesting idea here I think i'll use it. Glad to help! What are you building that has such a large triangular structure? Quote
DrJB Posted January 23, 2014 Posted January 23, 2014 (edited) Would this work? I'd add at least 3 more friction pins (connecting the short liftarms to the pulley wheels / wedge belt wheels) but it's surprisingly strong in-plane as is. This does not seem right. In fact, I tried building it, but could not. Looking at each of the vertices of the triangle, you cannot fit one liftarm in between two others, such that the angle between them is 30 degrees. For the middle liftarm to fit between the neighboring two, the spacing/gap must be equal to 1M. However here, we have 1.732 (=sqrt(3)) minus 1 = 0.732M ... So, the above photo is NOT possible without dramatically stressing the parts. Anyone else sees the dilemma? Edited January 23, 2014 by DrJB Quote
Kronos Posted January 23, 2014 Posted January 23, 2014 I just built this and it does stress the pins. Pretty badly too. Did the solution that darsedz came up with (post #7) work? What is it you're trying to build? If we had some more info maybe a better solution could be reached..... Quote
Hrafn Posted January 23, 2014 Posted January 23, 2014 (edited) This does not seem right. In fact, I tried building it, but could not. Looking at each of the vertices of the triangle, you cannot fit one liftarm in between two others, such that the angle between them is 30 degrees. For the middle liftarm to fit between the neighboring two, the spacing/gap must be equal to 1M. However here, we have 1.732 (=sqrt(3)) minus 1 = 0.732M ... So, the above photo is NOT possible without dramatically stressing the parts. Anyone else sees the dilemma? True, it does stress the pins, though my experience was that it wasn't too bad. Alternately you could keep the 3 outer pulley wheels, swap 7L liftarms for the 9L ones, and use 2x in the middle. And you could keep one of the spokes at 9L for additional rigidity. EDIT: yes, there's still some stress in the parts because the geometry isn't quite perfect - the spokes should be 0.08 studs longer than they are for perfect geometry. In practice it works reasonably well. Edited January 23, 2014 by Hrafn Quote
SNIPE Posted January 23, 2014 Author Posted January 23, 2014 (edited) This is for an off roader, each triangle has 3 wheels and there are 4 of them. Edited January 23, 2014 by SNIPE Quote
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