Sandwich panel insert

Claim 1

For combination with a panel sandwich assembly that includes a pair of spaced parallel panels interconnected by cellular structure, one of the panels containing a through opening, an insert partially receivable into said panel sandwich assembly through said through opening for retention, said insert comprising a. a shank and a pair of spaced heads integral therewith, the shank having an axis, one head being generally circular and of greater diameter than the one panel opening and the other head and shank being of lesser diameter opening whereby they may be inserted into the space between the panels, b. the one head defining an aperture to pass hardenable material into the panel sandwich assembly and into the space between the heads to permanently retain the insert to the panel assembly, the insert containing an axially threaded bore to which a threaded fastener may have access via said one head, and c. a radially inwardly yieldably retainer retained on the insert adjacent and at the side of the one head which faces the other head, the retainer located to be deflected radially inwardly when inserted through the one panel via said opening and to expand radially outwardly immediately adjacent the inner side of said one panel to cooperate with the said one head to temporarily retain the insert against dislodgement from the panel assembly prior to hardening of the material in said assembly, said retainer consisting of a elastomeric O-ring extending at the outer boundary of said aperture, and the aperture communicating the exterior with the space between the heads via the radially inner side of said 0-ring, said aperture being locally confined at one side of the shank axis and spaced radially outwardly from said axis and bore, the aperture overlying the 0-ring and also extending axially completely through the head more closely to the axis than the 0-ring, the head also defining an annular groove seating the radially innermost side of the 0-ring, said groove intersecting said aperture.