At 10:23 PM 5/20/2000 -0400, you wrote:> The slight 'catch' about this 'zero force' design is that unless the > belt >is 'completely flexible', bending the belt over the pulleys involves a force >which tends to pull the pulleys together - the natural shape of the 'straight >bit' forming the hinge is actually 'S' shaped. > > Regards, > > Chris Chapman Chris, Thanks for the nice explanation. It is a weird configuration to visualize. I think because of symetry, there should actually be zero residual moment. If you didn't mark the ends of the cylinders, you wouldn't be able to tell how much it had rotated. The flexures would all continue to have the same shape, whatever it was. In effect, as one flexure winds up, another is unwinding in exactly the opposite way. Think everything cancels out. Although, thinking about it, it's probable that the effect you're describing might well allow the axis of rotation to shift very slightly depending on the direction of the force on the hinge. That may be the problem. I'm hoping it's a pretty small effect. Regards, Brett __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>