Safe deposit lock construction with changeable tumbler mechanism

An improved multiple key lock assembly comprising, in combination:

• a housing,
• a bolt in said housing, said bolt slidable between a projected, locked position and a retracted unlocked position, said bolt including at least two separate locking projections extending from the bolt transverse to the direction of bolt travel;
• at least two separate gate tumblers mounted for engagement with the locking projections of said bolt to prevent sliding movement of the bolt from the locked position, said gate tumblers being pivotally mounted on separate connected posts;
• separate means for rotating each of said gate tumblers on said posts to a position of disengagement with the bolt locking projections to permit retraction of the bolt, said means for rotating including separate keys and separate associated pivotal key operated drive tumblers for each key, each drive tumbler engaging a radial portion of each gate tumbler to drive said gate tumbler between bolt engaged and disengaged positions, separate shifters including cam driving surfaces for slidably driving said bolt when the gate tumblers are oriented to permit bolt retraction;
• means for translating the connected gate tumbler posts and gate tumblers independent of the bolt and drive tumblers to thereby separate radial engagement of the gate and drive tumblers;
• and
• means for maintaining said gate tumblers, drive tumblers and bolt in a fixed position when the gate and drive tumblers are radially separated whereby the separate keys may be removed and replaced independently to provide a new radial relationship between the gate and drive tumblers upon reengagement thereof.