Expansion joint with water lock

Claim 1

In an integral expansion joint and water lock for installation in concrete slabs of decking for swimming pools and the like: A. an elongated tubular body of stiff and rigid but flexible plastic material having: a. an upper part in the generally cross-Sectional shape of an inverted U, there being a top wall substantially horizontal and flat at all times and adapted to be coplanar with the top surface of said decking, and sidewalls depending from the side edges of the top wall, said top wall being thicker than said sidewalls, b. and a lower part V-shaped in cross section, the oppositely arranged sidewalls thereof depending from the lower edges of respective sidewalls of the upper part, the point of the V forming a longitudinally extending ridge which facilitates pressing and entry thereof into soft concrete and prevents concrete from entering the hollow interior of said body, B. and oppositely arranged relatively wide lateral flanges extending longitudinally, continuously and integrally of the body, said flanges extending outwardly of the body and joining same, adjacent the upper end of said V-shaped part and enlarged beads on and extending along the free edges of said flanges for anchoring said flanges in the concrete, and outwardly opening grooves in the beads for reception of concrete when the expansion joint and water lock is installed in soft concrete so that the flanges and sidewalls of the upper and lower parts will be pulled laterally outward with contraction of the concrete upon setting thereof, the junction of the sidewalls of the lower part is weakened to facilitate separation of said sidewalls along the ridge with lateral pulling on the sidewalls during contraction of the concrete.