Abstract: In order to be able to shift a leader (18), which is disposed on a travelling chassis (10) via a carrying mechanism (16), both towards the front and also towards the rear into a substantially horizontal position, the carrying mechanism (16) has at least one guide arm (24) which is adjustable in length and which comprises a double-acting hydraulic working cylinder.

Abstract: A drilling tool, the drill head (16) of which can be connected either to a drill (10) or a casing string (28), is also fitted with an automatic direction reversing mechanism (64) which is designed so that the driven part (14) of the drill head (60) executes backward and forward movements of less than 90°, but preferably 20° to 30°. In this way the drill head can also strike the casing string when sinking it.

Abstract: For selective operation in a Diesel mode and a pressure air mode a Diesel type pile hammer is additionally equipped with a pressure air accumulator, which is connected to the working space of the cylinder by a servo valve.

Abstract: A drilling device comprises a drive motor (22), which sets a tool (36) in rotation, and a feed motor (14) which axially displaces the tool. Load sensors (12, 18, 20, 24) detect not only the tool feedrate (V) but also at least two of the three parameters, tool feed force (F), tool torque (M) and tool speed (U). An evaluation and control unit (70) evaluates the above-mentioned parameters and via control units (38, 42) activates the drive motor (22) and the feed motor (14) in such a way that the tool feed force (F) and the tool speed (U) or the tool torque (M) assume values at which the tool feedrate (V) for a specific ground hardness (H) is maximized.

Abstract: A boring tool with two driving heads which are used to sink a casing string and a borer string includes a controllable coupling mechanism fitted between the two driving heads. A mechanism is also provided for the lower driving head, such that the driving head is subjected to an additional downwards acting force. When both driving heads are coupled, the upper driving head is also subjected to an additional, downwards acting vertical force. In order to free the top end of the casing string, the coupling mechanism can be released so that the upper driving head can be fully raised, whilst the lower driving head remains in position adjacent to the ground.

Abstract: An illuminating or light emitting device for use as a headlamp, a signaling lamp or other lamp for shining light in a beam or otherwise. It comprises as its main parts a generally flat transparent illuminating element with a circumferential edge in which a plurality of light emitting elements such as LED's are set. The edges are provided with an inwardly reflecting layer. The front side of the illuminating element is in the form of a light radiating surface, while the rear side is completely covered with an inwardly reflecting layer. Such an illuminating device may have a very flat overall shape, has a low current requirement and has a large homogeneous radiating area. It more especially lends itself to use on vehicles.

Abstract: An illuminated display unit such as a board with a house number thereon or an advertising billboard, has a light guide panel. At least one electrical illuminating element is arranged in the vicinity of at least one lateral limiting edge thereof. The light guide panel serves for illuminating logo symbols, which are preferably in the form of film or of vapor coated layers, on the light guide panel. At least one of the lateral limiting edges of the light guide panel is provided with a light guide batten whose thickness is in excess of the thickness of the light guide panel and at least one of the illuminating elements is mounted in the batten. The transition between the light guide batten and the light guide panel is designed so as to have a high optical conductivity or transmittivity. The external surfaces of the light guide batten are provided at least partly with an inwardly reflecting layer.

Abstract: An illuminated display unit such as a house number, traffic sign, advertisement carrier and the like comprises a fluorescing or photoconductive plate adjacent an edge of which is fitted at least one light-emitting element, in particular a light-emitting diode. The edge is provided with a reflecting layer to prevent emergence of light. Display symbols or their negatives are arranged, as viewed by the onlooker, on the rear face of the photoconductive plate. As a result of the total reflection for a photoconductive plate on the front and back and on the reflecting layer at the edges, the light produced by the light-emitting diode can issue only at the contact surface with the display symbols, so that the light is concentrated very strongly there and a great display brightness is produced. This is even more effective when a contrast surface is arranged behind the plate.