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US5901506A
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Composite concrete and plastic manhole system
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Seal construction for bell and spigot pipe
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Lined conduit
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Transport vehicle having lift mechanism and associated extendible and retractable mobile object support
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Expandable core for casting concrete pipe
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Method of making wrapped tubular concrete
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Load lifting and transport vehicle
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Concrete-molding apparatus having an inner mold member with variable dimension periphery
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Wrapped tubular concrete pipe
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Method for pressure molding hollow cylindrical structures
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Pipe casting apparatus having vibrating means in physically separated adjacency to the core
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