Mine prop and shoe arrangement

Claim 1

A MINE PROP AND SHOE ARRANGEMENT WHICH COMPRISES A FIRST ELEMENT OPERATIVELY CONNECTABLE IN FIXED RELATION TO A MINE PROP, SAID FIRST ELEMENT HAVING A CONCAVELY CURVED SURFACE, A SECOND ELEMENT HAVING CONVEXLY CURVED SURFACE DISPOSED IN OPERATIVE SLIDABLE ENGAGEMENT WITH THE CONCAVELY CURVED SURFACE OF SAID FIRST ELEMENT TO PERMIT LIMITED ARTICULATE MOVEMENT OF SAID SECOND ELEMENT RELATIVE TO SAID FIRST ELEMENT, AND MEANS FIXEDLY CONNECTED TO SAID SECOND ELEMENT, AND MEANS OPERATIVELY CONNECTING SAID FIRST AND SECOND ELEMENTS FOR A LIMITED RELATIVE ARTICULATE MOVEMENT IN EACH OF TWO SELECTED PATHS FOR POSITIONING SAID SHOE MEMBER RELATIVE TO THE MINE PROP IN CORRESPONDING PATHS, SAID CONNECTING MEANS INCLUDING A MEANS DEFINING A PASSAGE EXTENDING THROUGH SAID SECOND ELEMENT, A PIN MEMBER EXTENDING THROUGH SAID PASSAGE MEANS, AND A COLLAR MEMBER OPERATIVELY CONNECTED IN FIXED RELATION TO SAID FIRST ELEMENT, SAID COLLAR MEMBER BEING OPERATIVELY CONNECTED TO THE END PORTIONS OF SAID PIN MEMBER, AND BEING DISPOSED IN SPACED-APART RELATION TO SAID SECOND ELEMENT TO LIMIT THE RELATIVE ARTICULATE MOVEMENT OF SAID FIRST AND SECOND ELEMENTS IN ONE OF SAID SELECTED PATHS, AND SAID PASSAGE BEING BOUNDED IN RELATION TO SAID PIN MEMBER TO LIMIT THE RELATIVE ARTICULATE MOVEMENT OF SAID FIRST AND SECOND ELEMENTS IN THE OTHER OF SAID SELECTED PATHS.