Self-drilling anchor

A self drilling anchor for use in a friable material mounted on a stud member, comprising:

• an elongated body having an axis, an axial bore having splines adapted to receive an elongated threaded fastener, a flared end having torque transmitting surfaces therein, a proximal portion, an intermediate portion, a distal portion, and a generally conical drilling tip generally opposite said flared end, wherein said intermediate portion tapers toward said distal portion, and said distal portion tapers toward said drilling tip;
• wherein said splines extend axially beyond said torque transmitting surfaces;
• wherein said body includes a first exterior thread disposed on said proximal portion, said intermediate portion, and said distal portion, wherein said first exterior thread has a lead proximate said drilling tip;
• and further wherein said first exterior thread has a generally equal pitch along said proximal portion, said intermediate portion and said distal portion;
• wherein said drilling tip has a drilling thread about said drilling tip and said drilling tip is adapted for drilling into said stud member;
• wherein said first exterior thread at said proximal portion has a crest diameter and a high thread height for gripping said friable material, said first exterior thread at said intermediate portion has a crest diameter substantially smaller than said crest diameter at said proximal portion and a thread height substantially smaller than said high thread height at said proximal portion, and said drilling thread having a crest diameter substantially smaller than said crest diameter at said proximal portion and a thread height substantially smaller than said high thread height at said proximal portion, said first exterior thread having a transition zone between said high thread height at said proximal portion and said thread height at said intermediate portion;
• said proximal portion having a length approximately equal to said friable material thickness;
• wherein the combined length of said intermediate portion and said distal portion is greater than said friable material thickness.

A self drilling anchor for use in a friable material mounted on a stud member, comprising:

• an elongated body having an axis, an axial bore having splines adapted to receive an elongated threaded fastener having a tip, a flared end having torque transmitting surfaces therein, a proximal portion having threads for gripping said friable material, an intermediate portion proximate said proximal portion and having threads adapted for gripping said stud member, a distal portion, and a drilling tip extending to an original position generally opposite said flared end, wherein said intermediate portion tapers toward said distal portion at a generally constant first angle with respect to said axis, wherein said distal portion tapers toward said drilling tip at a generally constant second angle with respect to said axis, said second angle being larger than said first angle;
• wherein said drilling tip has a drilling thread about said drilling tip and said drilling tip is adapted for drilling into said stud member;
• wherein said splines extend axially beyond said torque transmitting surfaces;
• wherein said body includes a first exterior thread disposed on said proximal portion, said intermediate portion, and said distal portion, wherein said first exterior thread has a drilling thread at said distal portion and has a lead proximate said drilling tip;
• and further wherein said first exterior thread has a generally equal pitch along said proximal portion, said intermediate portion, and said distal portion;
• wherein said first exterior thread at said proximal portion has a crest diameter and a high thread height, said first exterior thread at said intermediate portion has a crest diameter substantially smaller than said crest diameter at said proximal portion and a thread height substantially smaller than said high thread height at said proximal portion, and said drilling thread has a crest diameter substantially smaller than said crest diameter at said proximal portion and a thread height substantially smaller than said high thread height at said proximal portion, said first exterior thread having a transition zone between said high thread height at said proximal portion and said thread height at said intermediate portion;
• said proximal portion having a length approximately equal to said friable material thickness;
• wherein the combined length of said intermediate portion and said distal portion is greater than said friable material thickness;
• and
• wherein at least one of said intermediate portion and said distal portion is frangible so that said elongated fastener can break off a portion of said elongated body so that said elongated fastener tip can extend beyond said original position of said drilling tip.

A self drilling anchor for use in a friable material, comprising:

• a thin-walled, elongate body having an axis, an exterior thread, an axial bore adapted to receive a fastener, a proximal end having torque transmitting surfaces, and a drilling end having a generally conical drilling tip opposite the proximal end;
• said drilling tip having a drilling thread that is substantially uninterrupted around said drilling tip;
• structural support means, including said drilling thread with a root that tapers toward said drilling tip and a lead proximate the drilling tip for providing sufficient structural support to withstand a torsion force required for the drilling end to penetrate a substrate adjacent the friable material, the substrate having a hardness greater than the hardness of the friable material;
• said body further comprising a proximal portion adjacent the proximal end having threads for gripping said friable material, a distal portion adjacent the drilling end, and an intermediate portion having threads adapted for gripping said substrate therebetween, said proximal portion having a length approximately equal to said friable material thickness and said intermediate portion proximate said proximal portion;
• wherein the combined length of said intermediate portion and said distal portion is greater than said friable material thickness;
• and wherein said proximal portion threads, said intermediate portion threads and said drilling thread have a generally equal pitch.