device for maintaining a predetermined mittenabstandes the supports of a schreitausbaues for langfrontenabbau

摘要

The invention is concerned with apparatus for maintaining a set "between-centers" distance between the elements of self-advancing mine-roof supporting means for long-wall mining, the support means having at least two elements connected via connecting means so that they can pivot to a limited extent with respect to an abutment which, in use, extends substantially parallel to the long-wall face, the connecting means of at least one element being constructed as a drive means, in which the portions of the abutment connected to the respective connecting means are interconnected so that their length can be varied, and a guide lever is pivoted to the connecting means of at least one element and to an abutment portion connected to an adjacent element so that the two places at which the lever is pivoted and the place at which the connecting means of the first-mentioned element are connected to the abutment lie at the corners of a triangle.