Abstract: In an eye cup for an eyepiece of an optical observation apparatus, for individual and convenient adjustment of the eye cup it is provided that a second adjusting element can be rotated in a mode dependent on a compressive force independently or together with a first adjusting element, such that a light-shield section can be positioned as desired for any distance of the adjusting elements with respect to one another.

Abstract: A cup for an eyepiece of an optical observation instrument, comprises a peripheral wall which includes an eyepiece-connecting section for connection of the cup to an eyepiece, a transition section which adjoins the eyepiece-connecting section, a light-protecting attachment which, by way of a sectional part of the transition section, is joined to a side of the transition section that is turned away from the eyepiece-connecting section; a sight hole which is laterally defined by the peripheral wall; the peripheral wall being movable into a first, non-folded end position for someone who does not wear spectacles for preclusion of any incidence of stray light upon an eyepiece lens, and into a second, folded end position for spectacle wearers; and into a third stable position of ventilation, located between the first and the second end position, for someone not wearing spectacles.

Abstract: In a cup for an eyepiece of an optical observation instrument, comprising a peripheral wall which includes an eyepiece-connecting section for connection of the cup to an eyepiece, a transition section which adjoins the eyepiece-connecting section, a light-protecting attachment which, by way of a sectional part of the transition section; is joined to a side of the transition section that is turned away from the eyepiece-connecting section; a sight hole which is laterally defined by the peripheral wall; the peripheral wall being movable into a first, non-folded end position for someone who does not wear spectacles for preclusion of any incidence of stray light upon an eyepiece lens, and into a second, folded end position for spectacle wearers; it is provided, with a view to the possibility of use of the optical observation instrument without any negative effect for someone who does not wear spectacles as well as for spectacle wearers, that the peripheral wall is movable into a third stable position of ventilati

Abstract: For making drill holes, in particular under cramped conditions, an apparatus is used which comprises a drill rod consisting of individual segments and guided in the cradle or slide. The individual segments comprise end pieces which are constructed as centering bushes and guide bushes and are to be pushed into each other in such a manner that the necessary torques and pressure forces can be effectively transmitted from the drilling motor. The drilling motor itself is displaceable between two clamping tongs which fix the drill rod or the individual segments and ensure that the latter form in each case a rigid unit to which the pressure and rotary forces can thus be effectively transmitted. The flushing hose extending in the individual segments is connected via a rotary duct to the guide segment of the drill rod so that said hose itself does not participate in the rotation and can therefore be led with the loosely engaging segments round a curve.

Abstract: The invention concerns an extrusion device for impregnating rock formations preferably for bonding with a liquid synthetic product, with the use of a piston pump having at least one working cylinder. During the induction or suction stroke a working piston is filled with the extrusion liquid or with one of its components, and is emptied during the delivery stroke cycle. The working piston is controlled by a pump drive equipped with at least one driving cylinder and a driving piston which can be pressurized on both sides of the piston sequentially. A control valve pressurizes the piston surface with a working fluid as the other working surface of the piston is relieved. The extrusion device, can operate with more efficient utilization of the energy source applied and in particular with extremely high operating pressure of the available hydraulic medium, which is already available but used for other purposes, i.e., the operation of the rams or the hydraulic face- and/or roadway supports.