Rohl

Action for infringement of patent No. 1,610,570, applied for October 16, 1924, and issued December 14, 1926. The patent is for new and useful improvement of knockdown and portable combination form and traveler for constructing inclined concrete arches, and the litigation involves the construction of dams.

Dams of the type here involved are made up of a series of arches extending across the course of the stream, supported on buttresses extending in the direction of the stream flow. The buttresses are first constructed, and the arches are supported between the buttresses, the convex or outer face of the arch up stream and the concave or interior down stream. The dam is built inclined down stream from the perpendicular. ' Since the water pressure increases with the depth, the dam is constructed heavy at the base tapering upward. Por the same reason the buttresses taper towards the top.

A secure foundation having been found and buttresses built, forms are prepared into which the concrete forming the dam is poured, that forming the exterior curve, or upstream face of the arch, is called the extrados, and the complementary form, the one that forms the interior curve or downstream…