US3566501A - Method of making spiral chute - Google Patents
US3566501A US830084A US3566501DA US3566501A US 3566501 A US3566501 A US 3566501A US 830084 A US830084 A US 830084A US 3566501D A US3566501D A US 3566501DA US 3566501 A US3566501 A US 3566501A Authority US United States Prior art keywords slide edge spiral chute spiral chute Prior art date Legal status (The legal status is an assumption and is not a …