Cylinder lock and key

A reversible key for a cylinder lock comprising:

• a bow;
• a blade longitudinally extending from said bow and comprising a pair of sides and a pair of longitudinally extending oppositely disposed spaced edges which interconnect said sides, said sides being at least in part substantially parallel to one another;
• and
• a projection extending outwardly from each of said oppositely disposed parallel parts of said edges in fixed relationship therewith, said projections being substantially in alignment, said projections having a minimum width at the free ends thereof which is less than the width of said parallel parts of said edges, said projections each being shaped to define at least a first cam surface, said cam surface facing the end of the blade disposed oppositely to the bow.

A cylinder lock system comprising:

• a key comprising a bow portion and a blade which longitudinally extends from said bow portion to a tip, said blade having a pair of transversely spaced parallel edges which are interconnected by side surfaces, said blade being provided with surface irregularities which define the key bitting, a shaped camming projection transversely extending from each of said edges, said projections being aligned and being spaced from but adjacent to the junction of said blade and bow portion;
• shell means including a shell having a longitudinal axis, said shell means defining at least a first row of primary pin tumble means receiving chambers and an auxiliary pin tumbler means receiving chamber, said shell means further defining an engagement surface traversing an interior portion thereof;
• plug means rotatably mounted in said shell means, said plug means having a forward face and a longitudinally extending keyway, said keyway having a first slot portion of reduced height and a second slot portion of greater height when compared to said first slot portion, said second slot portion opening through said face for receiving said key so that said key projections may be inserted into said enlarged slot portion, said plug means defining at least a first row of primary pin tumbler means receiving chambers alignable with said shell means primary pin tumbler means receiving chambers and an auxiliary pin tumbler means receiving chamber alignable with said shell means auxiliary pin tumbler means receiving chamber, a shear line being defined between said shell means and said plug means;
• and
• pin tumbler means reciprocally mounted in said plug means chambers, said pin means having first ends which are normally biased into said keyway and second ends oppositely disposed with respect to said first ends, said pin means extending across said shear line, said pin means second ends engaging respective of said shell means chambers whereby said pin means coact with said plug means and shell means in the locked condition of the lock to prevent rotation of said plug means relative to said shell means, said pin means each defining a shear line;
• insertion of said key in said keyway resulting in a first one of said projections engaging a pin means in said plug means auxiliary pin tumbler means receiving chamber and camming said engaged pin means radially outwardly whereby the shear line of said engaged pin means registers with the shear line between the key plug means and the shell means, the key blade surface irregularities causing the pin tumbler means in the primary chambers to be reciprocated to present shear lines at the plug/shell shear line whereby rotation of said plug means relative to said shell means to the unlocked position of the lock is permitted, the other of said projections being slidably rotatable and longitudinally engageable against said engagement surface.