Cartridge loading devices

A cartridge loading device for magnetic tape cartridges, said device comprising a first member, a second member movable relative to said first member from a first position to a second position, a guide arrangement for guiding movement of said second member between said first and second positions and comprising a projection received in an elongate guide track defining a line of movement for said projection having a first end defining said first position and a second end defining said second position, and a locking system comprising a pivotable locking member engageable with said projection for locking said second member in said first position, said first and second members cooperating when in said first position to define a first sized opening having a height sized to receive first sized magnetic tape cartridges having a predetermined height and, when in said second position, cooperating to define a second sized opening having a height that is greater than the height of said first sized opening, said second sized opening being sized to receive second sized magnetic tape cartridges having a predetermined height that is greater than the height of said first sized magnetic tape cartridges, said locking member being actuable by insertion of a second sized cartridge into said first sized opening to release said projection to permit movement of said second member from said first position to said second position, and said pivotable locking member having a pivot point disposed on a line that is in line with at least a first portion of said line of movement, which first portion extends from said first end.