Seal assembly for annular hydraulic cylinder

A seal assembly comprising:

• an annular insert structure of rigid material centered on an axis and having an annular outer structure, an annular inner structure, left and right annular radial faces, and a continuous annular right groove in said right radial face;
• and
• an annular seal member of elastomeric material bonded to the insert structure, filling said right groove, and extending to the right of the insert structure to form a seal structure defining an outer annular sealing surface having a relaxed configuration positioned radially outwardly and to the right of the annular outer insert structure and an inner annular sealing surface having a relaxed configuration radially inwardly and to the right of the annular inner insert structure;
• the insert structure further defining a continuous annular left groove in the left annular radial face of the insert structure;
• the insert structure having an I-beam cross-sectional configuration having left-right symmetry and including an outer annular flange structure forming the annular outer structure, an inner annular flange structure forming the annular inner structure, and an annular web structure extending radially between the inner and outer flange structures and having a left face coacting with left portions of the inner and outer annular flange structures to form the left groove and coacting with right portions of the inner and outer annular flange structures to form the right groove;
• the insert structure further defining a plurality of circumferentially spaced holes extending through the web structure and connecting the left and right grooves;
• the elastomeric material filling the left groove and filling the holes whereby to interconnect the elastomeric material in the left groove with the elastomeric material in the right groove.