Apparatus for making longitudinally prestressed concrete pipes

Claim 1

A LONGITUDINALLY PRESTRESSED CONCRETE PIPE MOLD ASSEMBLY COMPRISING A CYLINDRICAL MOLD SHELL, END RINGS AT THE ENDS OF THE SHELL HAVING EACH AN OUTWARDLY FACING END FACE SHOULDER, A PLURALITY OF LONGITUDINAL PRESTRESS RODS IN CIRCUMFERENTIALLY SPACED RELATIONSHIP ABOUT THE INTERIOR OF SAID SHELL, EACH ROD COMPRISING AN END BUTTON ON AT LEAST ONE END SPACED SO AS TO BE LOCATED OUTSIDE THE RESPECTIVE END RING AND A WASHER AT EACH END SPACED INWARDLY FROM THE RESPECTIVE END BUTTON AND ANCHORED IN FIXED POSITION ON THE ROD, SAID WASHERS BEING SPACED INWARDLY OF THE RESPECTIVE END RINGS, EACH END RING HAVING A HOLE THERETHROUGH FOR EACH ROD, A UNITARY BOLT LOOSELY RECEIVED IN THE HOLE IN THE RESPECTIVE END RING, MEANS SECURING EACH END OF THE ROD TO THE RESPECTIVE END RING AGAINST TENSION ACTING INWARDLY RELATIVE TO THE END RING, AT LEAST ONE OF SAID MEANS COMPRISING A BOLT IN THE HOLE IN THE RESPECTIVE END RING HAVING A BORE THERETHROUGH GREATER IN DIAMETER THAN THE END BUTTON, SAID BORE HAVING AN ENLARGEMENT AT ONE END FORMING A SHOULDER AND A SPLIT COLLAR SURROUNDING SAID ROD AND FORMING AN ANCHOR IN SAID ENLARGEMENT BETWEEN THE SHOULDER AND THE BUTTON, AND A NUT ON THE BOLT IN SNUG ENGAGEMENT WITH THE RESPECTIVE END RING AFTER THE ROD HAS BEEN PLACED UNDER LONGITUDINAL TENSION WHEREBY TO PRESERVE THE TENSION IN THE RESPECTIVE ROD UNTIL CONCRETE HAS BEEN PLACED AND ALLOWED TO SET IN THE MOLD.