Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gullick Dobson Ltd
Original Assignee
Gullick Dobson Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gullick Dobson LtdfiledCriticalGullick Dobson Ltd
Publication of FR2164761A1publicationCriticalpatent/FR2164761A1/fr
Application grantedgrantedCritical
Publication of FR2164761B3publicationCriticalpatent/FR2164761B3/fr
E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
E21D23/00—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor
E21D23/08—Advancing mechanisms
E21D23/081—Advancing mechanisms forming parts of the roof supports
E21D23/082—Advancing mechanisms forming parts of the roof supports acting solely on the elements of the supports