That's a good point RJ, I was wondering that myself. Do you think this spring method is confined to benchtop CNC or is it also present in big boy machines (with appropriate spring sizing).
Downwind, I think the role of the pins is to allow the 2 nuts to float axially but not allow rotation between then, which would defeat the anti-backlash setting. Its kind of the same principle as the slit nut concept with jack screws to open the one nut side up relative to the other. But in that mode they share a common base where the slit doesn't separate them completely. Technically I think they open up with an axial component but also a bit of hinged action to it (not in a perpendicular plane to leadscrew if that makes sense). A little bit cheesy but they are used extensively in the imports.
Downwind, I think the role of the pins is to allow the 2 nuts to float axially but not allow rotation between then, which would defeat the anti-backlash setting. Its kind of the same principle as the slit nut concept with jack screws to open the one nut side up relative to the other. But in that mode they share a common base where the slit doesn't separate them completely. Technically I think they open up with an axial component but also a bit of hinged action to it (not in a perpendicular plane to leadscrew if that makes sense). A little bit cheesy but they are used extensively in the imports.