Expansion dowel

Expansion dowel for insertion into an opening in a receiving member, such as a plate, wall, hollow block or similar structural member having a hollow space inwardly of the surface through which the dowel is inserted, the dowel has a leading end which is inserted first through the opening so that at least a portion of the dowel extending from the leading end extends into the hollow space, and a trailing end, the dowel comprises an axially extending tubular shaft portion extending from the trailing end toward the leading end, a flange portion located at and extending transversely of and outwardly from said shaft portion at the trailing end, said shaft portion having a bore extending axially therethrough, a pair of flexible expansion arms connected to said shaft portion, a pair of webs with each said web connected to a different one of said expansion arms and said webs being interconnected, the dowel has an inserting position with the expansion arms and webs extending in the axial direction of said shaft portion and located closely together, and an expansion position with each said expansion arm and said web connected to it extending transversely outwardly from the axis of said shaft portion, wherein the improvement comprises that said expansion arms have a first end connected to said shaft portion at a location spaced from the trailing end of the dowel and a free second end spaced longitudinally from the first end in the axial direction of said shaft portion when the dowel is in the inserting position, said webs each have a first end and a second end spaced longitudinally apart with the first end flexibly connected to the associated said expansion arm and the second end connected to the second end of the other said web, in the inserting position said expansion arms and webs extend in generally paraallel relation along the axis of said shaft portion and in the expansion position said webs extend at an acute angle to the portion of the associated said expansion arm extending between the first end of said expansion arm and the junction of said web and the associated said expansion arm, the portion of said expansion arm extending from the junction with said web to the second end thereof extends approximately perpendicularly to the axis of said shaft portion, and the first end of each said web having a reduced thickness portion connected to the associated said expansion arm at a location approximately mid-way between the first and second ends of said expansion arm with the reduced thickness portion forming the flexible connection between said web and said expansion arm.