Pin tumbler lock

A lock comprising:

• housing means defining a keyway and a plurality of tumblerways communicating therewith;
• a tumbler disposed in each of said tumblerways and adapted for both reciprocating and rotational movement therein, each of said tumblers movable between locked positions into at least one shear position comprising both a predetermined longitudinal position and a predetermined angular position within its said tumblerway, each of said tumblers comprising one end surface defining an alignment surface extending into said keyway;
• rotational bias means biasing each of said tumblers into biased angular positions other than said predetermined angular positions;
• release means movable between open and closed positions and adapted for operative coupling with a latch mechanism, said release means being movable from said closed position to said open position with all of said tumblers in said shear positions and being restrained in said closed position with any of said tumblers in one of said locked positions;
• and
• a key insertable into said keyway and having a plurality of alignment portions, each of which is adapted to engage a different one of said alignment surfaces, the elevation and orientation of said alignment portions and surfaces being such as to move said tumblers into their shear positions.