Lamp (logo) ID  

Maybe it stands for Staff...
Maybe it stands for Staff Leuchten, Lighting Manufacturer - W Germany. But might not be the same lamp.
http://adoremodern.com/archive/stehlampe-von-staff.htm

That link doesn't seem to...
That link doesn't seem to work.. sorry

Yes ...
... that's right, it's a STAFF lamp.

Staff indeed!
You were right, it seems to be a lamp from Staff Leuchten from the '50s or '60s. I did some research with those keywords and I found a few more links:
- http://www.19west.de/de/produkte/staff-tischleuchte-1960s?page=5
- http://www.hollandinvorm.com/index.php?option=com_content&view=article&i...
- http://adoremodern.com/archive/tischleuchte-von-staff.html
- http://www.ebay.com/itm/Pair-Mid-Century-Modern-Germany-Staff-Leuchten-T...
I think the brand might be owned by the Zumtobel Group now, but I'm not sure. I emailed them, so I'll get back with a follow-up as soon as I hear from them. If only for future reference.
Great forum! Thanks a lot!

...
...right, STAFF has been taken over in 1993 by Zumtobel.