Loose leaf binder

A loose leaf binder comprising:

• a pair of elongated base plates (42, 44) arranged side-by-side;
• a plurality of half rings (20, 30) integrally supported respectively on these base plates, in such manner that half rings form closed rings when their respective pairs of the free ends abut each other;
• a plurality of bearings (14) formed integrally with rear surfaces of the respective base plates (42, 44) and having a common axis between the base plates, a gap formed between the bearings (44) in such manner that the base plates can be relatively moved along the common axis between a first position where respective pairs of half rings (20, 30) are aligned with each other and a second position where the respective pairs of half rings (20, 30) are not aligned;
• and a shaft or shafts supported by the bearings (14) on the rear surface of the base plates (42, 44), wherein
• at least one hook (104) is formed on the one base plate (42 or 44) and adapted to engage with an outer edge of the other base plate when the half rings (20, 30) are in the closed position, and
• at least one lock release groove (106) is formed on the other base plate (44 or 42) and adapted to release the hook (104) from the engagement with the outer edge when the half rings (20, 30) are displaced to the second position where the half rings (20, 30) are not aligned and the hook (104) drops into the lock release groove (106).