Air-operated drilling machine or rotary-percussive action

Abstract

The machine has a braking arrangement for retaining it against rearward motion and rotation and includes a housing accommodating therein a hammer reciprocable in operation of the machine and adapted to strike the head part of the housing, the latter having a drilling tool rigidly connected thereto. The tail part of the housing supports a sleeve rigidly connected with the braking arrangement. The housing and the sleeve are connected so that the housing is rotatable and axially displaceable relative to the sleeve. The drilling tool rotating mechanism is positioned intermediate the sleeve and the housing and includes a helicoidal couple made up by a helicoidally threaded rod rigidly secured to the housing and a nut, the mechanism further including a freewheeling clutch of which the movable cage is made integral with the nut. Upon the hammer having delivered a blow upon the housing, the tool connected with the latter recoils from the rock of the face of the hole, this recoil driving the tool together with the housing rearwardly from the face, whereby the housing cooperates with the rotating mechanism, and the tool is rotated. The invention is intended to utilize the effort of the recoil of the tool, as it strikes the face of the hole, for rotation of the drilling tool.