Ring drilling apparatus and method

Claim 1

IN A DRILLING APPARATUS PARTICULARLY ADAPTED TO DRILL A RING OR FAN OF DRILL HOLES TRANSVERSELY OF AND IN A ROW PERIPHERALLY AROUND AN UNDERGROUND DRIFT, A SUPPORT ADAPTED TO BE MOVED ALONG SAID DRIFT TO SUCCESSIVE RING DRILLING LOCATIONS, AN ELONGATED FRAME, A PAIR OF COAXIAL TRUNNIONS IN OPPOSED TRANSVERSE DISPOSITION CENTRALLY ON SAID FRAME, A ROCK DRILL, AN ELONGATED FEED BAR FOR SLIDABLY CARRYING SAID ROCK DRILL, FEEDING MEANS ON SAID FEED BAR FOR FEEDING AND RETRACTING SAID ROCK DRILL ALONG SAID FEED BAR, PIVOT MEANS ON SAID ELONGATED FRAME FOR MOUNTING SAID FEED BAR ROTATABLY ON AN AXIS PERPENDICULAR TO SAID TRUNNIONS AND EXTENDING TRANSVERSELY TO SAID FRAME, FLUID PRESSURE OPERATED MEANS MOUNTED ON SAID FRAME AND HAVING OPERATIVE CONNECTION WITH SAID FEED BAR FOR TURNING SAID FEED BAR ABOUT SAID PIVOT MEANS, FLEXIBLE MEMBER MEANS CONNECTED TO AID SUPPORT AND TO SAID TRUNNIONS FOR CARRYING SAID FRAME BY SAID TRUNNIONS WITH SAID TRUNNIONS SUSPENDED IN SUBSTANTIALLY HORIZONTAL POSITION THEREBY TO GIVE SAID FRAME A CERTAIN FREEDOM OF MOVEMENT IN ALL DIRECTIONS FOR ADJUSTING PURPOSES, AND MEANS ON SAID FRAME ADAPTED TO ENGAGE IN ERECT POSITION OF SAID FRAME PORTIONS OF SAID DRIFT FOR IMMOBILIZING SAID FRAME IN ADJUSTED ERECT POSITION IN SAID DRIFT DURING DRILLING OF SAID RING OR FAN OF DRILL HOLES.