Patent ID: 7413367

Claim:
A combinational commodity engaging unit engaging a first plate with a second plate of a combinational commodity, said engaging unit comprising at least: a fixing seat embedded in said first plate and having a top portion with an engaging hole, said engaging hole being provided therein with an engaging groove of which an inner radius is larger than an inner radius of said engaging hole, wherein a bottom portion of said fixing seat is embedded in a fixing hole of said first plate, said bottom portion of said fixing seat having a connecting portion having a function of reversing proofing; a hollow engaging member embedded in a through hole of said second plate, said hollow engaging member including a head embeddable in said through hole, a protruding shaft extending from said head to a distal end and adapted to extend through and out of said through hole, and a central passage extending through said head and said protruding shaft; wherein said protruding shaft is embedded in said engaging hole of said fixing seat and has on its outer wall a protruding elastic positioning portion spaced from said distal end having an outer radius which is larger than said inner radius of said engaging hole, said elastic positioning portion being radially compressed when inserted into said hollow engaging member and expanding to elastically engage in said engaging groove; and a fixing rod extended into said hollow engaging member, comprising a stem having an outer surface which is tapered towards a bottom end, said bottom end of said fixing rod having a protruding portion with a diameter in coincidence with an inner diameter of said central passage of said hollow engaging member; wherein when said fixing rod is extended into said central passage of said hollow engaging member, said protruding portion abuts the interior of the hollow engaging member at a location axially between said elastic positioning portion and said distal end, and is tightly abutted on an inner wall of said central passage, such that said elastic positioning portion is expanded and engaged in said engaging groove, and the outer surface of said protruding shaft abuts the interior surface of the engaging hole at said distal end radially adjacent said protruding portion.