This is a standard old school adjustable cup bottom bracket with bearings in a retainer. Here's a link to Park Tool's instructions for bottom bracket adjustment.

http://www.parktool.com/blog/repair-...racket-service

For the adjustment, you will need a lock ring spanner, a pin type adjustable cup spanner and whatever you need to remove the non-driving side crank. Not mentioned in the Park Tool article: tightening the lock ring will tend to make the bearings looser. You can make and adjustment quicker by over tightening the adjustable cup slightly before tightening the lock ring.