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Publication date
Publication of BE486554ApublicationCriticalpatent/BE486554A/xx
E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
E21D15/14—Telescopic props
E21D15/28—Telescopic props with parts held relatively to each other by friction or gripping
E21D15/38—Telescopic props with parts held relatively to each other by friction or gripping with longitudinally-divided upper or lower prop parts, e.g. interfitting laminations
E—FIXED CONSTRUCTIONS
E21—EARTH OR ROCK DRILLING; MINING
E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
E21D15/14—Telescopic props
E21D15/28—Telescopic props with parts held relatively to each other by friction or gripping
E21D15/40—Collar or other support gripped to one or both parts by toggle-action, cam, or other member pivoted or similarly mounted