IPC Subgroup
E21D 15/34 by axially-moving balls, rollers, or the like
Introduced: September 1968
Last revised: January 2006
Full Title
Props; Chocks > Telescopic props > with parts held relatively to each other by friction or gripping, e.g. using wedges > by axially-moving balls, rollers, or the like
Classification Context
- Section:
- FIXED CONSTRUCTIONS
- Class:
- EARTH OR ROCK DRILLING; MINING
- Subclass:
- SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS