Abstract: Electrically powered trolley vehicles in headings of mines are provided with a current collector pick-up unit having contact-sensing means, current collectors, position sensors and guide wheels. The power supply for the pick-up unit comprises an array of elongated guide rails and at least two conductor bars. The connecting method comprises running the vehicle slowly forwards, by means of its own energy source, in the direction of the elongated conductor bars and vertically raising the pick-up unit by means of an arm mounted on the vehicle so that a contact-sensing frame for sensing contact in a vertical direction is brought into engagement with one or both of the guide rails. During a continued vertical movement, the contact-sensing frame is turned down towards the rest of the pick-up unit and when the contact-sensing frame reaches its lower end limit position, this is indicated by a position sensor.

Abstract: A method for controlling the lateral displacement of a trolley supporting goods to be unloaded at an unloading location, the goods being releasably attached to the trolley by an elongated flexible member. The method is characterized in that the trolley, which supports the goods, via the elongated flexible member during a first phase of the unloading operation, is decelerated from a certain lateral displacement speed at which it approaches the unloading station and, at least after part of the unloading operation of the goods, is accelerated in the opposite direction, whereby the retardation phase and the acceleration phase are invidually carried out within less than one period of the pendulum motion of the elongated flexible member. The method can be used in cases where the length of the flexible member varies during the approach of the goods to the unloading location.

Abstract: Cloud altitude measurement is carried out in a step-by-step manner wherein the measuring distance is changed by a predetermined amount for each measurement step. First and second integrators respectively integrate reflected echo signals during respective first and second time intervals T.sub.1, T.sub.2 with T.sub.1 <T.sub.2. The first integrator integrates reflected light pulses and noise and the second integrator integrates noise. The difference between the integrated signal outputs from the first and second integrators is determined by a summation device and a controllable level-sensing signal evaluating device emits a signal if the aforesaid difference exceeds a predetermined value. The signal evaluating device is controlled to emit the indicating signal when a number of consecutive measurement steps have been measured.

Abstract: A cloud altitude measuring means for detecting the existence of and the distance to a cloud comprising a light emitting means, a light receiving means, a plurality of integrators activated at separate time intervals to receive the output signal from the light receiving means, a signal summation device to receive and determine the difference between the signals in the said integrators, and a signal processing circuit to receive the output signal from the signal summation device, which circuit comprises a memory circuit to store a first series of measurement value pulses from said summation device and a comparison device for comparing the first series of measurement value pulses stored in the memory with a second time delayed series of measurement value pulses to detect a cloud echo when the comparative difference between the measurement value pulses exceeds a specified value.

Abstract: For determining oblique visibility, for example on an airport, a light emitter emits a light beam and is coupled with a light receiver. A plurality of devices are located at different, known distances from the light receiver, which launch measuring bodies substantially vertically with a predetermined height for each of the units. The measuring bodies are arranged to reflect the light emitted from the light emitter back to the light receiver where the visibility is sufficient. The devices are operated sequentially.

Abstract: A tubular electrode contains a feeding tube forming an annular passage between its outside and the inside of the electrode. With the electrode forming a cathode, an arc is formed between it and a carbonaceous iron bath in an enclosed hearth having a gas outlet. Iron oxide material in flowable form is fed through the inner tube to the arc while a non-oxidizing gas is fed via the passage formed between the two tubes, to the arc. The carbonaceous iron bath is made the anode and the action of the current forms an upward bulge in the metal in the arc, gravitationally freeing the bath from any slag at the arc. In this way the iron oxide material is melt reduced, the iron component being continuously added to the bath which may be continuously tapped to provide a supply of crude iron.