Method and apparatus for improved masonry drive anchor

An apparatus for retaining an element to a surface having a pre-formed recess in said surface for receiving a portion of said apparatus and retaining that portion via an interference fit, comprising:

• a generally cylindrical shank extending at each end along a first longitudinal axis and adapted to be received within said recess;
• an enlarged head portion formed at one end of said shank;
• a free end portion formed on said shank at an end opposite said head portion;
• a plurality of pre-formed undulations formed on said shank intermediate said head and free end portions;
• said undulations forming at least one pair of peaks elevated from the cylindrical surface of said shank, those peaks being spaced apart along said first longitudinal axis;
• and
• the portion of said shank between said pair of peaks being formed as a continuous curve and having an inflection point along that curve with the slope of the shank at said inflection point being nonparallel to said first longitudinal axis such that upon insertion of said shank into said recess compresslye forces are exerted on each of said peaks within that pair which directly oppose each other so as to maintain a tight interference fit within said recess and minimize distortion of said apparatus beyond said peaks.

A fastener adapted to be pounded into a pre-formed surface recess to retain an object to said surface by an interference fit of said fastener within said recess, comprising:

• a head portion,
• an upper shank portion connected to said head portion and formed as a substantially uniform body extending along a longitudinal axis,
• an S-shaped bend portion connected to said upper shank portion and formed with at least two pre-formed peaks in paired relation extending radially outwardly with respect to the surface of said upper shank portion and a continuous curve portion between said peaks having therein an inflection point in the curvature of said bend portion, the slope of the surface of said continuous curve portion at said inflection point being non-parallel to said longitudinal axis, and
• a lower shank portion connected to said bend portion and formed as a substantially uniform body extending along said longitudinal axis.

An anchor bolt system for retaining an object to a masonry surface, comprising:

• a pre-formed hole in said masonry surface, said hole having an interior surface,
• a resilient anchor bolt adapted to be driven into said hole and to be retained therein via an interference fit with said interior surface,
• said bolt having a head portion which remains outside of said hole and a shank portion which is inserted into said hole and engages said interior surface,
• said shank portion including an upper portion adjacent to said head portion and a lower portion at the free end of said shank, said upper and lower portions each being formed as a right cylinder extending along a longitudinal axis and each thereby having a cylindrical surface at a substantially uniform radius from said axis,
• said shank portion including two adjacent, preformed peak portions in paired relation intermediate said upper and lower portions, said peak portions each being raised with respect to said cylindrical surface such that the peak portions extend radially outward from said axis further than said cylindrical surface,
• said peak portions being adjacent such that the length of said shank therebetween includes no surface extending parallel to said cylindrical surface, and
• said peak portions having a radial distance therebetween of sufficient length that said interior surface exerts force on said peak portions to compress those peak portions toward said axis when said bolt is inserted into said hole, that compression force being exerted on one of those peak portions being directed directly against the compressire force on the other of said paired peak portions.