2014-08-26 4:20 GMT+03:00 Gregg Eshelman <[email protected]>: > If you want more Z height, you can raise the gantry rails (as this table > is made) or use a drive chain at each end down to drive the pinions on > the racks. Or skip racks and leadscrews and use stationary chains looped > up around idlers to the drive shaft as high as you want. > > https://www.youtube.com/watch?v=vETkf1sqo3M > > Yet another way to drive a tall gantry with low side rails would be a > vertical shaft at each end with bevel gears to go around the top corners > and mounting racks and pinions vertically at the bottom.
Let me stop you there, compared to vertical shafts at each end and bevel gears and all the axial bearings they need, 2 motors is "dead simple" solution. As I said, more than 30-50 mm Z height is not compatible with "dead simple" and "accessible workspace". Raised gantry rails are exactly what I would like to avoid. Yes, fixed chain _might_ be solution, but it tends to stretch: 1) one has to check it once in a while, until then there is risk of backlash 2) if one chain stretches more than other (could be different loads, if in special cases), then there can be different travel distances for the same count of pinion teeth. Viesturs ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
