Machine for piercing a taphole for a shaft furnace

Machine for piercing a taphole for a shaft furnace, according to a method in which, after having plugged the taphole with taphole clay, a metal rod is driven into this clay, before it has fully hardened, and it is extracted, at the desired time, with a view to opening the taphole, the machine comprising:

• a mounting having a front and a rear;
• a front support for supporting the rod at the front of the mounting;
• a sliding rear support for supporting the rod at the rear of the mounting;
• a first clamp, mounted in a sliding manner on the mounting, the rod passing axially through said first clamp, said first clamp including means for gripping the rod at any place between said front support and said rear support;
• a jack having a travel distance C, the distance C being less than the length of the rod, said jack mounted on the mounting;
• a travel multiplier connected between the jack and the first clamp so that the first clamp may be moved by said jack over a distance 2C along the mounting, the distance 2C being two times the travel distance C of the jack;
• and
• control means for controlling the jack in order to move the first clamp in a to-and-fro motion between a position (B) at the front of the mounting and a position (A) which is located at a distance L from the position (B), the distance L being less than the length of the rod.