Expansion anchor unit

Claim 2

An expansion anchor system comprising a first member of substantially flat configuration and having a leading portion provided with cutter edges for drilling a hole in a support structure, and a trailing portion converging in direction away from said leading portion and having a first engaging portion extending towards said leading portion; a second member provided with a forward end portion having a second engaging portion extending rearwardly and being matingly but releasably engageable with said first engaging portion of said trailing portion of said first member, and with a rearward end portion engageable by a tool operative for jointly rotating both of said members in a sense effecting drilling of a hole in a support structure by said cutter edges; a third member having a front portion and a screwthreaded rear portion, said third member being provided with at least one third engaging portion in form of a slot dimensioned for entry of said first member and extending from said front portion towards said rear portion so as to subdivide at least the former in two parallel sections which spread apart in radially outward direction in response to forcible axial insertion of said third member into the drilled hole subsequently to disengagement of said second member from said first member and withdrawal of said second member, the entry of said first member iNto said third member resulting in radial expansion of said front portion into wedging engagement with the wall bounding said hole.

Claim 3

An expansion anchor system comprising a first member of substantially flat configuration and having a leading portion provided with cutter edges for drilling a hole in a support structure, and a trailing portion converging in direction away from said leading portion and having a first engaging portion extending towards said leading portion; a second member provided with a forward end portion having a second engaging portion extending rearwardly and being matingly but releasably engageable with said first engaging portion of said trailing portion of said first member, and with a rearward end portion engageable by a tool operative for jointly rotating both of said members in a sense effecting drilling of a hole in a support structure by said cutter edges; a third member having a front portion and a screw-threaded rear portion, said third member being provided with at least one third engaging portion in form of a slot dimensioned for entry of said first member and extending from said front portion towards said rear portion so as to subdivide at least the former in two parallel sections which spread apart in radially outward direction in response to forcible axial insertion of said third member into the drilled hole subsequently to disengagement of said second member from said first member and withdrawal of said second member, the entry of said first member iNto said third member resulting in radial expansion of said front portion into wedging engagement with the wall bounding said hole.

Claim 4

An expansion anchor system comprising a first member of substantially flat configuration and having a leading portion provided with cutter edges for drilling a hole in a support structure, and a trailing portion converging in direction away from said leading portion and having a first engaging portion extending towards said leading portion; a second member provided with a forward end portion having a second engaging portion extending rearwardly and being matingly but releasably engageable with said first engaging portion of said trailing portion of said first member, and with a rearward end portion engageable by a tool operative for jointly rotating both of said members in a sense effecting drilling of a hole in a support structure by said cutter edges; a third member having a front portion and a screw-threaded rear portion, said third member being provided with at least one third engaging portion in form of a slot dimensioned for entry of said first member and extending from said front portion towards said rear portion so as to subdivide at least the former in two parallel sections which spread apart in radially outward direction in response to forcible axial insertion of said third member into the drilled hole subsequently to disengagement of said second member from said first member and withdrawal of said second member, the entry of said first member iNto said third member resulting in radial expansion of said front portion into wedging engagement with the wall bounding said hole.

Claim 5

A system as defined in claim 1, said first member having two opposite sides, a pair of projections each being provided on one of said sides and offset with reference to the other projection; wherein the second member has an outer circumferential surface and is provided with a rearwardly extending slot in said forward end portion and a pair of elongated recesses extending rearwardly in said forward end portion along respective diametrally opposite edges of said slot, for receiving the respective projections therein when said first member is in part located in said slot; and wherein said third member is also provided with a pair of elongated recesses in its outer circumference extending rearwardly in said front portion along respective diametrally opposite edges of said slot in said third member.

Claim 6

A system as defined in claim 1, said first member having two transversely spaced surfaces extending between opposite ends of said leading and trailing portions; further comprising at least a pair of projections each provided on one of said surfaces and elongated substantially in direction between said opposite ends; and mating recesses provided in said forward end portion of said second member and said front portion of said third member and being positioned to receive the respective projections for preventing displacement of the respectively engaged members with reference to one another.

Claim 7

A system as defined in claim 3, said second member having an outer circumferential surface; and further comprising at least two helically convoluted grooves provided in said outer surface extending between the axial ends of said forward and rearward end portions and each having in the region of said forward end portion a groove section which extends in at least substantial parallelism with the longitudinal axis of said second member and constitutes one of said mating recesses.

Claim 8

A system as defined in claim 3, said projections being convexly curved in direction outwardly from the respective surface.

Claim 9

A system as defined in claim 1, said second member being of polygonal cross-section and helically twisted about its longitudinal axis.

Claim 10

A system as defined in claim 6, wherein the cross-section of said third member decreases stepwise in direction from said rear portion towards said front portion.

Claim 11

A system as defined in claim 1; further comprising a plurality of ridges provided on an outer circumferential surface of at least said front portion and encircling the latter.