abatteuse-chargeuse à chaîne de havage

CONT: Abatteuses-chargeuses de chambres et piliers. Ces machines conçues et réalisées aux Etats-Unis sont sorties du stade prototype vers 1950. En 10 ans, elles ont conquis plus de 20 % du charbon américain et leur champ d'activité s'étend. Elles sont soit du type à chaîne de havage découpant le charbon par saignées parallèles, soit du type rotatif détruisant le massif à la manière de perforatrices à taillant de très gros diamètre. La première et la plus connue est le continuous miner de Joy (...)

CONT: Joy presently offer both chain ripper miners and the rotary drum head-type miners introduced in 1968. However, the rotary drum head machines are proving to be the more popular and look to be superseding the chain ripper models produced by Joy. In operation the chain ripper machine works as follows. The machine is trammed forward into position then, while the main chassis of the machine remains stationary, the cutting head moves forward, sumping into the coal at the bottom of the face. The rotation of the chains carries the broken coal back over the head and deposits it on to the chain conveyor which then moves the coal to the rear end of the machine. When the sumping operation is complete, the head travels upwards towards the top of the seam, breaking out the coal as it moves. As soon as the cycle is complete the head is withdrawn and swung to the side in order to make another cut.
OBS: trammed: Technical term used for the driving backward and forward of such machinery.