Clamping insert

In combination, a plate member having a supporting edge, a grooved member having a groove of greater width than the thickness of said plate member for receiving said edge and a clamping insert for gripping the sides of said plate member at said supporting edge and for insertion with said supporting edge into said groove, said insert comprising an elongated body of elastomeric material having a central portion and side portions, said side portions having locking flanges extending outwardly from the outer faces and ribs extending inwardly from the opposing inner faces for engagement with the sides of said plate member, the thickness of said side portions and said ribs being greater than the difference between the width of said groove and the thickness of said plate whereby said ribs are compressed into gripping engagement with the sides of said plate, said groove having an end and sides with slots in the sides of said groove for engaging said locking flanges of said side portions of said clamping insert in locking engagement in said slots and said elastomeric material being stretchable whereby said clamping insert may be elongated to reduce the thickness of said side portions including said ribs to compensate for dimensional variations of the plate member, grooved member and clamping insert.