Anchor bolt with mechanical keys deployed by internal pressurization

An anchor bolt for providing an anchor site in a matrix of solid material which has an accessible face having a generally cylindrical socket formed therein through said accessible face,

• said anchor bolt comprising:
• a shaft constructed and arranged to be snuggly received one end first into the socket so as to have an axially inner portion embedded in the matrix and an axially outer stub portion protruding outwardly of said accessible face;
• means defining at least one cavity generally centrally within the axially inner portion of the shaft;
• means defining a longitudinally extending passageway in said shaft, said longitudinal passageway extending from communication with said cavity, to the exterior of said stub portion of said shaft;
• at least one respective radially extending passageway extending in said shaft between each said cavity and the exterior of said shaft axially inner portion;
• a key of hard, durable material wholly recessed in each said radially extending passageway, each such key, said at least one cavity and said passageways being constructed and arranged for direct exposure of each such key to superatmospheric fluid pressure when applied to said at least one cavity, and being constructed and arranged for direct, engaging penetration of said matrix upon being driven radially outwardly;
• and
• means, operable via said longitudinal passageway, for producing such a surge of superatmospheric fluid pressure in each said cavity, that each said key is driven radially outwardly in the respective radially extending passageway to a position of partial-length protrusion radially from said shaft, so that the anchor bolt may be firmly locked in the socket in which its axially inner end portion is received.