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Publication of BE646930ApublicationCriticalpatent/BE646930A/xx
E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
E21D15/58—Devices for setting props or chocks
E21D15/585—Devices for setting props or chocks by means of hydraulically operated devices for mechanical props, or hydraulic props in which the hydraulic part is not important
E21D15/586—Devices for setting props or chocks by means of hydraulically operated devices for mechanical props, or hydraulic props in which the hydraulic part is not important the props being pre-loaded
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
E21D15/44—Hydraulic, pneumatic, or hydraulic-pneumatic props