Mounting member

A mounting member for supporting a fastening member, comprising:

• a substantially horizontal support surface;
• a pair of elongate webs depending from said support surface;
• a pair of flanges extending inwardly toward each other from, and transversely to, free ends of said pair of webs so as to define a slot between inner opposed extremities thereof;
• said fastening member having in a plan view a rectangular head portion which has a pair of longer sides and a pair of shorter sides;
• said support surface, inner side surfaces of said pair of webs, and said pair of flanges defining therebetween a groove which has a width greater than said slot defined between said opposed extremities of said flanges in such a manner as to allow insertion of said head portion of said fastening member into said groove when said longer sides of said head portion are oriented substantially along said slot, said width of an upper portion of said groove allowing rotational movement in a horizontal plane of said head portion of said fastening member therebetween;
• and
• a pair of enlargements formed within a lower portion of said groove and within transversely spaced corner portions of said groove defined between said inner sidewall surfaces of said pair of webs and said flanges extending therefrom, said pair of enlargements extending longitudinally along said groove and including a pair of sloped portions, and allowing longitudinally opposite end portions of said head portion of said fastening member to rest within said lower groove portion when said fastening member is orientated with said shorter sides being disposed substantially parallel to said inner sidewall surfaces of said pair of webs along said lower portion of said groove but preventing said rotational movement of said fastening member within said lower portion of said groove as a result of said longitudinally opposite end portions of said head portion of said fastening member having respective undersurface inclined, sloped surfaces which are complementary to said pair of sloped portions portions of said enlargements while providing increased mechanical strength to said corner portions of said groove so as to withstand bending moments impressed thereon by means of loads attached to said fastening member due to the inward disposition of said head portion of said fastening member relative to said inner sidewall surfaces of said pair of webs.