A safety device for a drilling rig of the type wherein a drill-carrying cradle is caused to move upwardly or downwardly on a tower by a chain which traverses sprockets at opposite ends of the tower. Shock loads and vibration cause premature failures in the chain when withdrawing a drill string as the cradle is pulled upwardly on the tower. The present invention minimizes shock loads on the chain to minimize the possibility of a chain failure and, at the same time, prevents a fall of the cradle and drill carried thereby if the chain above it should break, this latter function being accomplished with the use of spring-loaded toothed dogs on the cradle which engage the tower and prevent movement of the cradle in the event of a chain failure.
A device for inserting a substantially vertical drainage wick, comprising a movable frame; an inserting lance which is provided with a passage for receiving the drainage wick and corresponding with the longitudinal axis of the inserting lance; a standing guide for the inserting lance supported by the frame; a supply mechanism for arranging the drainage wick in unwindable manner; a drive; a transmission connected to the drive; and at least on drive member coacting with the transmission, the inserting lance drive including a closed loop of a flexible element with one part of the closed loop coacting with the transmission and the other part of the loop fixed to the inserting lance.
A device for reciprocating motion of a rotating drilling body of a drilling machine in the longitudinal direction of a hole drilled in rock or ground includes two cylinder-piston devices which via chains are connected to a carriage carrying the drilling body and which comprise parallel piston rods, the ends of which are supported by a frame on the machine, and cylinders movable along the piston rods and connected to each other and via the chains also to the carriage. To increase the feeding velocity of the carriage or to increase the force of the carriage one of the cylinders or both cylinders, respectively, are selectively fluid pressurized.
A thrust system for a horizontal directional drill is provided. The thrust system includes a drill boom having a drive sprocket positioned at the first end thereof and a driven sprocket positioned at the second end thereof. A carriage for supporting the horizontal drill is slidably received on the drill boom. The carriage includes idler sprockets positioned between the drive sprocket and driven sprocket in the drill boom. A serpentine chain extends about the drive sprocket, the driven sprocket and the idler sprockets in order to provide greater thrust and pullback of the drill at given torques. Rotation of the drive sprocket in a first direction draws the carriage towards the first end of the drill boom, and rotation of the drive sprocket in a second direction draws the carriage towards the second end of the drill boom.
