Abstract: The present invention provides a crawler unit having a superstructure and a substructure and an excavating device for recovering bulk material. The excavating device has bearing regions and drive regions and also has vertically arranged shearing drums for cutting free the bearing and drive regions. The shearing drums have upper ends which are inclined obliquely forward.

Abstract: This invention relates to an improvement in a roll crusher which crushes loaded material by impact and pressure, comprising a crusher housing, a loading hopper, a rotatable roll holding impacting tools, and fixed or adjustable crushing bars mounted to the crushing wall of the crusher housing, the improvement comprising two mutually oppositely rotatable rolls, each independent of the other and adapted to crush the material, mounted together with two oppositely located crushing walls in one common crusher housing, and a roof-like chute means mounted above a gap between the two rolls and adapted to distribute the material in the hopper and feed it to crushing regions.

Abstract: This invention relates to an improvement in the process for improving the impregnability of wood which is pierced on its surface prior to an impregnation procedure by means of solid, circular needles which are guided essentially perpendicularly to said wood surface, without thereby causing chipping or splintering, the improvement comprising using sharp, circular needles with smooth surfaces, rotating about their central axes, and at an essentially constant ratio of the peripheral speed (u) of these needles to their speed of advance (v) with which they drive into the wood.

Abstract: This invention relates to a process for introducing holes or straight or circular slots approximately normal to the surface in the vicinity of the surface of round timber and to an approximately predetermined depth for the purpose of facilitating the penetration of impregnating means into the surface zones of the timber to better protect against chemical and biological attacks.