Trough manufacturing process

The method of making a troughing section having an arcuate bottom wall joined to parallel vertical side walls, the bottom wall sloping at a predetermined angle relative to horizontal when the upper edges of said walls are horizontal, comprising the steps of:

• (A) forming a planar section blank by severing the longitudinal edges of a piece of sheet metal linearly in opposite directions and each at an angle equal to the desired slope angle of the section bottom,
• (B) interposing the blank between a forming die and a forming roller, the die having a convex exterior forming surface conforming in shape and size to the desired interior shape and size of the section bottom,
• (C) clamping the blank and the forming die in relatively fixed positions with the forming die initially contacting one side of the blank at the juncture of one side wall portion of the blank and the bottom wall portion of the blank and the roller contacting the other side of the blank in direct opposition to the die,
• (D) displacing said forming roller to traverse the forming die while maintaining continuous rolling blank-roller contact and continuous relatively fixed blank-die contact, and
• (E) continuing the performance of step (D) above beyond the point at which the longitudinal edges of said blank come into alignment to allow for spring-back of the section side walls into substantially parallel relation following the performance of step (D).

A method of making an open-top U-shaped channel for the gravity flow of a liquid, comprising the steps of:

• (A) feeding a flat parallel edge metal sheet along a horizontal table in a direction parallel to said edges,
• (B) clamping said sheet onto the table,
• (C) cutting opposite ends of each said sheet to form an isosceles trapezoidal-shaped sheet with parallel sides corresponding to said parallel edges, and cutting successive sheets so that adjacent sheets have one equal length side, and each successive sheet has one side edge shorter than the shortest side edge of the former sheet,
• (D) clamping each said trapezoidal sheet along a line perpendicular to its sides and intermediate its converging end edges at bottom edge of one side of a to-be-formed U-shaped trough section,
• (E) wrapping the free longer portion of each said clamped sheet around a convex mandrel to form a U-shaped trough section with parallel sides,
• (F) welding equal length U-end edges of adjacent trough sections together to form said U-shaped channel, and
• (G) welding a flanged frame onto the open ends of said channel.

A method of making an open-top U-shaped channel for the gravity flow of a liquid comprising the steps of:

• (A) feeding a flat parallel edge metal sheet along a horizontal table in a direction parallel to said edges,
• (B) clamping said sheet onto the table,
• (C) cutting opposite ends of each said sheet to form an isosceles trapezoidal-shaped sheet with parallel sides corresponding to said parallel edges, and cutting successive sheets so that adjacent sheets have one equal length side, and each successive sheet has one side edge longer than the longest side edge of the former sheet,
• (D) clamping each said trapezoidal sheet along a line perpendicular to its sides and intermediate its converging end edges,
• (E) wrapping the longer portion of each said clamped sheet around a convex mandrel to form a U-shaped trough with equal parallel sides,
• (F) welding equal length U-end edges of adjacent troughs together to form a channel section,
• (G) welding a flanged frame onto the open top edges of said channel section,
• (H) welding adjacent channel sections together in situ embedded into a floor, and
• (I) placing removable covers on said frames over said open channels.