GB190612124A - A New or Improved Tunnel Excavating Machine. - Google Patents

Abstract

12,124. Davies, D. May 24. Jacks. - Relates to a rotary tunnelling-machine which grinds the face and conveys the spoil to the back of the machine and is advanced by means of simultaneously operated screw jacks having means for automatic reversal. The screw p of each jack revolves in a casing p<1> and is formed with a shaftg whereon are loosely mounted wheels q<1>, q<2>. A drum s on the head a gears with the wheel q<1> and with a wheel r in gear with the wheel q<2>. A rod t passing through the screw is secured to clutches u, u<1> and carries a disk t<1>. Normally, the clutch u engages the wheel q<1> and the screw is extended from the barrel. When the disk t<1> comes into contact with the end of the barrel p<1>, the clutch u is disengaged, the clutch u<1> being engaged and the screw p driven into the barrel. To retain the screw in gear, the clutch u<1> is connected to an arm w which carries an arm v<1> connected to a spiral spring v. When the arm v<1> passes its dead-centre, the spring presses the clutch u<1> firmly home. According to the Provisional Specification, the screws may be reversed by means of sun-andplanet gearing.