PROCEDE ET DISPOSITIF POUR MAINTENIR L'ORIENTATION DE LA TIGE DE FORAGE D'UNE FOREUSE

摘要

A method and apparatus for maintaining alignment of the drill steel or drill rod of a drilling machine in which a midpoint centralizer or indicator ring having an aperture therethrough substantially greater than the diameter of the drill rod or drill steel is used like a rifle sight to indicate the nature and degree of misalignment so that adjustments can be made in the operating mechanisms of the drilling machine or the support and positioning mechanisms for the drilling machine to remove the cause of the misalignment and to return the drill steel to its centered, aligned position in the indicator ring. In normal operation the drill steel does not contact the indicator ring so that noise transmission and frictional losses normally associated with midpoint centralizers is avoided. Mechanical contact between the drill steel and indicator ring occurs only to limit the maximum deflection and maximum stress which will occur in the drill steel due to bending. Guided by the indications at the indicator ring a skilled operator can greatly reduce or substantially avoid the occasions when mechanical contact actually occurs.