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
E21D15/32—Telescopic props with parts held relatively to each other by friction or gripping by a deformable collar or clamping means applied symmetrically inside a locking ring
E21D15/325—Telescopic props with parts held relatively to each other by friction or gripping by a deformable collar or clamping means applied symmetrically inside a locking ring by a clamping ring
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
E21D15/58—Devices for setting props or chocks
E21D15/584—Devices for setting props or chocks in which a series of similarly shaped props obtain an almost equal load capacity by removable devices