DLuders Posted October 12, 2011 Posted October 12, 2011 (edited) aklego posted this of a "A LEGO lemniscate linkage. The center of the middle bar traces the lemniscate of Bernoulli [figure-8 pattern]. In the dark shots, the linkage is lit with black light causing the small green disk to fluoresce." You can look at this when you're ready for bed, and dream of infinite Lego creations.... Edited October 12, 2011 by DLuders Quote
Burf2000 Posted October 12, 2011 Posted October 12, 2011 I don't know how that works but that is pretty clever! Quote
dikkie klijn Posted October 12, 2011 Posted October 12, 2011 (edited) That looks great! I think it works on gravity. When the arm wants to go up, more force is needed then when the arm goes down. EDIT: no it isn't gravity, is it? Edited October 12, 2011 by dikkie klijn Quote
Crtlego Posted October 12, 2011 Posted October 12, 2011 That's pretty neat. I think its because of the differential which allow one arm to lift at a different speed than the other so that when they go in different directions it doesn't blow up.. Quote
aklego Posted October 12, 2011 Posted October 12, 2011 Hi All, Thanks for the post! In order for this mechanism to work fluidly, each rotating arm needs a cycloidal angular velocity profile--you can see the brief pause that each arm make as it sweeps one revolution. However, it works out nicely as the two rotating arms are 180° out of phase and the sum of their angular velocities is a constant. That is where the differential comes in and it sorts everything out. Quote
parda Posted October 13, 2011 Posted October 13, 2011 (edited) I Love this kind of devices, i have to taken a minute to know why it use a differential bu in fact it is essential and smart, I will try to reproduce it If I can Edited October 13, 2011 by parda Quote
DLuders Posted October 13, 2011 Author Posted October 13, 2011 (edited) @ aklego: Welcome to Eurobricks! I see from your YouTube channel that you like building various Lego "whirlygigs". By chance did you display your " " (below) at BrickFest 2009 in Portland, Oregon USA? I remember seeing something like it there. Do you have any photos of it posted anywhere on the net so that we can examine its intricacies? I like your Lego too! You wrote, "This is a LEGO Technic Hyperbolic Paraboloid. It is an example of a ruled surface. See http://en.wikipedia.org/wiki/Ruled_surface for more info": Edited October 13, 2011 by DLuders Quote
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