Rock bolts

Claim 1

A ROCK BOLT COMPRISING A ROUND STEM TO BE PUT IN TENSION OVER A LENGTH EXTENDING INWARDLY FROM THE MOUTH OF A HOLE TO AN ANCHORING LOCATION WITHIN THE HOLE, IN COMBINATION WITH AN ANCHORING UNIT CONNECTED TO SAID INWARDLY EXTENDING LENGTH OF THE STEM, A BEARING UNIT CONSISTING OF A BRIDGING MEMBER TO SPAN THE MOUTH OF THE HOLE AND FORMED WITH A CONICAL APERTURE CONVERGING TOWARD SAID ANCHORING UNIT AND RECEIVING SAID STEM, TOGETHER WITH A PLURALITY OF WEDGES OPERATIVELY DISPOSED ABOUT THE STEM WITHIN SAID CONICAL APERTURE, SAID WEDGES BEING FORMED EXTERNALY TO FIT THE CONICAL APERTURE AND FORMED INTERNALLY WITH GRIPPING SURFACES TO EMBRACE THE ROUND STEM, SAID BRIDGING MEMBER HAVING GRIPPING SURFACES FOR FRICTIONALLY ENGAGING THE FACE OF THE ROCK SURROUNDING SAID MOUTH OF SAID HOLE TO POSITION SAID INWARDLY EXTENDING LENGTH OF SAID STEM WITHIN SAID HOLE IN RESPONSE TO SAID TENSION, SAID INWARDLY EXTENDING LENGTH OF THE STEM BEING PROVIDED WITH THE SAID ANCHORING UNIT CONSISTING OF AN INNER MEMBER FORMED BY AN ALIGNED CONICAL EXTENSION OF THE STEM, SAID EXTENSION DIVERGING FROM A NARROWER END INTEGRALLY CONNECTED TO THE STEM TO A WIDER TERMINAL END SO AS TO PROVIDE A CONICAL SURFACE, AND A PLURALITY OF OUTER HOLE-GRIPPING MEMBERS IN THE FORM OF LONGITUDINAL SHELLS TOGETHER SUBSTANTIALLY SURROUNDING THE CONICAL EXTENSION, SAID OUTER GRIPPING MEMBERS BEING FORMED EXTERNALLY WITH SERRATIONS FOR GRIPPING THE WALL OF THE HOLE AND INTERNALLY WITH CONICAL SURFACES SHAPED TO ENGAGE AND FIT THE CONICAL SURFACE OF THE EXTENSION WHEN SAID EXTENSION IS DISPLACED LENGTHWISE BY PART OF ITS LENGTH RELATIVELY TO THE SHELLS IN THE DIRECTION OF SAID NARROWER END, WHEREBY SAID TENSION IN SAID STEM ALONG THE LENGTH BETWEEN SAID MOUTH OF SAID HOLE AND SAID ANCHORING LOCATION IS MAINTAINED BY THE COOPERATION OF SAID WEDGES WITH SAID STEM.