Patent ID: 7477478

Claim:
A deep storage slot with a constant spring force comprising: a storage slot housing defining a cartridge cavity and a cartridge opening, wherein said cartridge cavity is configured to store a plurality of cartridges in depth; a constant force spring comprising a rolled, pre-stressed strip that exerts a constant force to resist uncoiling, said constant force spring having a first end affixed to said storage slot housing within said cartridge cavity to direct said constant force towards said cartridge opening; at least one retention feature configured with said storage slot housing to hold at least one of said plurality of cartridges within said cartridge cavity against said constant force; a spring spool associated with said constant force spring, wherein said spring spool comprises a structure separate from said constant force spring and includes a middle portion and outer portions, wherein said outer portions include a greater diameter or height than said middle portion, wherein said outer portions are distinct from said inner portion, wherein said constant force spring is configured to roll and unroll around said middle portion of said spring spool as said constant force spring moves within said cartridge cavity, wherein said outer portions are disposed in contact with at least one of said cartridges and said inner portion is disposed out of contact with said cartridges, wherein the constant force spring is rotateable about said middle portion while said outer portions remain in a non-rotating condition and contact at least one of said cartridges.