FI65335C - ANORDNING FOER AUTOMATISK LAENGDMAETNING AV BACKHOPP - Google Patents

Description

2 65335 - As the descent speed of hill jumpers is about 100 km / h, the human eye, due to its slowness, cannot identify the exact point of descent; - The unfavorable lighting and weather conditions often prevailing during hill jumps make it difficult to determine the actual point of descent; - Competition judges may intentionally criticize the performance of downhill jumpers in an increasing or decreasing manner.

On the negative side, it can still be said that a large staff is needed in the visual measurement procedure for jumps.

In addition to the current known visual method, a few other procedures have been tried to measure the length of hill jumps with greater accuracy and more objectively. These include: Radiation fence method; - Ultrasonic distance measurement method based on the sonar principle; - Induction loop laser track measurement method; - Laser infrared measurement method, in which a number of sensors are placed along the downcomer; - Direct inductive meander method; - Radar-based electronic jump length measurement procedure. Said methods are briefly described below.

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In the rain fence method, optical or acoustic radiation poles are set at certain intervals, the direction of the rays of which is perpendicular to the direction of jumping and so low from the ground that the hill jumpers cut off the rays when descending. The reported jump length is highly dependent on the position of the hill jumper. Environmental conditions such as snowfall, fog, reflection, freezing, and noise can have a very detrimental effect on reliability. Maintenance costs are very high.

The sonar of the sonar operating on the sonar principle indicates the start time of the jump, at which the length measurement begins. The practical operation is not known. The attenuation of ultrasonic waves during snowfall and fog can be considered harmful. The rustle of the wind * can also be disturbing. Interference sounds may completely prevent the use of the method. The reflective properties of sportswear can be very different. Each hill jumper must carry a beeper for signaling the time of descent.

In the laser track measurement method with induction hoods, (Falun, Sweden 1974) »laser infrared fences are placed at specified intervals on the edges of the runway, the direction of the rays being perpendicular to the direction of jumping and so low from the ground that the jumpers cut off when landing. The electromagnetic signal pulse generated by a suitable transmitter when the ski hits the ground is received by an induction loop covering the entire jump range, which starts a time clock. Now mark the time that elapses until the next laser fence is cut. This also detects the time it takes to cut the next laser track. When the spacing of the laser tracks is known, it is possible, provided that the speed does not change and that the body position is unchanged, that the descent point be calculated arithmetically.

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Errors can be caused by changes in speed and body position, as well as maintenance, adjustment and inspection errors of the laser tracks in different snow conditions. Another significant drawback of this method is that each hill jumper must carry a signal transmitter to carry. Intentional external interference is thus easily possible.

In the laser infrared measurement method, in which a number of sensors are placed along the descent path, a laser infrared transmitter is placed on the hill jumper's shoe, which at the moment of descent transmits a pulse in a rectangular direction in the jump direction of about 3 * 10 "^ s. orbital sensors and tune several infrared sensors to measure the width of their own jet. The electronic connection then determines the center of the area in question and indicates the length of the jump.

There are also a number of disadvantages associated with this method: - It is difficult to readjust the radiation columns when the snow height changes; - Radiation columns depend on weather conditions; - A device that emits a laser pulse is placed on the ski or shoe; - Each hill jumper must have cable connections connecting the battery compartment, trigger contact and laser pulse transmitter.

The direct inductive meander method has not yet been tested in jumpers. The contact in the shoe provides inductance at the time of descent. A meander-shaped cable loop transverse to the track is placed on the descent slope 5 65335, and this is reserved at 70 Hz. Between two adjacent conductors are simple wires that are in an unused state without power. If the balance of the output is disturbed by connecting an inductance to the center conductor, a signal is generated. The electronic connection indicates the descent point in due course. Such a large number of test leads is difficult to keep for a long time without power in different environmental conditions. The hill jumper must have a contact and a coil.

The radar-based electronic measurement method uses a signal transmitter, a pressure switch and a radar reflector to determine the correct descent time. Two radars measure the distance below the jumper, one on the right side of the runway and the other on the left side at a height of about 10 meters from the jumper. A third radar, attached directly to the jumper, measures the distance in the higher range.

The main disadvantages are: - the equipment that every hill jumper must use; - high costs; - high maintenance costs for ski jumpers' equipment.

More detailed information on this method can be found in the brochure: K. Kreiselmeyer, M. Bolkart, K.H. Schmall "Electronic Sprung-Veitenmessung Voraussetzung - Stand - Ausblick" Verlag W.Steinbruck Baden-Baden (1976).

The above-mentioned methods of measuring length automatically summarize the following drawbacks: - The ski jumper has to carry with him, on a ski or attached to himself equipment with a relatively large weight of 6,653,35 which must be maintained and which impedes the athlete's free movement; - More or less severe interference with environmental conditions and intentional interference;

High equipment acquisition costs.

The object of the invention is to provide a device for automatically measuring the length of hill jumps, which is usable and inexpensive, operates almost without maintenance, is not subjective and is independent of environmental conditions. The proposed device looks like a whole new solution to the task.

Methods to date rely on the hill jumper approaching the descent at an extremely gentle angle. In order to determine the downlink location, it has therefore been necessary to provide an ultra-short signal at the time of the downlink, which is received and utilized by the receiver in a suitable form. The required signal strengths require a heavy beacon to be carried with the ski jumper. As a result, the aim has been to increase the sensitivity of the receiving devices or to find new good transfer principles. Moreover, it has not been known that the use of aeronautical specialties opens up entirely new possibilities for the creation of devices for automatically measuring the length of hill jumps.

The device according to the invention is based on the fact that the entire area of the jumper's downcomer area is covered with known measuring loops which act as receiving antennas. These measuring loops are suitably mounted under snow or lawn cover in a normally rectangular manner, for example at a distance of 0.5 m in the planned flight direction of the hill jumper. Each measuring loop is connected to a suitable signal amplifier. A small rod-shaped permanent magnet known per se is placed in front of the bandage on the hillside, the athlete can decide which ski the permanent magnet is attached to. After the entry stage of the hill jumper, the distance of the permanent magnet placed on the ski to the measuring loops is so small that an electrical signal is induced in these cases in any case. These signals are then transmitted through the signal lines and the amplifier to the central unit. Amplifiers are installed in the immediate vicinity of the measuring loops. In the central unit, each signal has a memory location. The logic electronic circuit indicates where the first signal is carried, etc. Each measurement loop and thus each memory location is proportional to a given hop length as measured from the effort edge of the jumper.

If the measurement loops are placed, for example, every 0.5 m, the jumps can be measured with an accuracy of 0.5 m. The jump length thus measured can be immediately communicated by means of the communication unit. The described method can be used up to a snow height of 0.8 m. However, different snow heights require that the gain of the amplifiers in the measuring loops be adjusted in the best possible way. I saw e.g. preventing signals from being induced in more than one measuring loop at the same time.

Analyzes of the descent technique have shown that the hill jumper descends primarily at the back of the ski and then only at the tip, followed by a high relative speed of the ski tip. For this reason, care must be taken to install the permanent magnet in the hillside as far as possible from the ski binding, as this reduces the distance between the permanent magnet and the measuring loops immediately before the end of the glide. When the permanent magnet is quite small, weighing about 12 g, this is not a disadvantage. 8 65335 inspection loops handle the optimal adjustment of the gain of the measuring loop amplifiers, manually or automatically, as well as the functionality of the largest parts of the length measuring device. These are located on the descent slope of the jumper rather perpendicular to the measurement loops. They are supplied with electrical impulses, which in turn induce similar signals in the measuring loops as those produced by the permanent magnet.

During the check phase, the gain is gradually changed until the signals of the measuring loops correspond to the given standards. The degree of validation thus obtained is maintained for the next inspection.

The method according to the invention has the following advantages: a simple structure of the length measuring device; - high measurement accuracy of jump length determination; * - reliability of use; - low maintenance costs; low susceptibility to interference relatively low acquisition and installation costs.

In the following, we present an embodiment of the invention. In this case, the descent area of the jumper is illustrated in Fig. 1, and in Fig. 2 the ski ski and the permanent magnet attached to it.

In the given embodiment 3, Figure 1 shows the descent slope (1) and the jump (2) of a hill jumper. Measuring loops (3) »are mounted on the downhill slope at points x ·), Χ2 ··· χη» and are connected to the central unit, which consists of a controller, a calculating section and an output section, via a measuring loop amplifier (5).

The check loops (4) fed through the amplifier (6) cover all measuring loops.

The measuring pins consist of wire threads that cover the required part of the descent slope. The supply and return lines 9 65335 run in parallel at distances of 0.20 m. Ao. the loops are transverse to the descent slope and the loop plane is parallel to the snow cover.

Suitably the measuring loops are insulated cable conductors with sufficient mechanical strength. To prevent the risk of accidental injury, the measuring loops are installed under a blanket when it comes to snow, under the snow or when using a net on its loops. In any case, the installation of the measuring loops must be carried out in such a way that no additional danger is posed to the ski jumpers.

It should be noted that the input and return lines of the measuring loops are always connected to the respective inputs of the amplifier.

The wires from the measuring loops to the amplifier as well as from the amplifier to the central unit are shielded.

The amplifier has a symmetrical input, which achieves: - high common signal propagation; - 20 Hz ... 40 Hz emission range; - 50 Hz blocking circuit; - automatic optimal gain adjustment in the range: 1 * 103 ... 150-10 ?; - threshold cut-off.

The signal from a single measuring point is fed to the memory of the central unit via a conventional input circuit. From there, they are entered in parallel in the shift register, from where they are printed serially combined. The result is given in numerical units and entered on the display board.

The inspection loop also consists of a conductor thread made of an insulated cable conductor. These are considered

Claims (2)

10 65335 by means of plastic sheet strips at a distance of 0.20 m from each other. The inspection loop is kept in an unused state due to its length (over the measuring loops) on the drum. The inspection loop is applied to the snow or mat before the start of the hill jump to optimize the degree of gain of the measuring loops and the amplifier. In this case, current is supplied from the generator with a sinusoidal voltage in the frequency range of 20 Hz to 40 Hz and a current of about 3 A. Figure 2 shows a permanent magnet in the ski, which is suitably glued or screwed to the ski by means of a flange sleeve or rubber sheath. The permanent magnet and the sleeve weigh about 12 g and have a size of 8 mm and 6 x 15 mm. The magnetic polarity must always be parallel. A device for measuring the length of hill jumps automatically, characterized in that the device consists of a permanent magnet suitably placed in front of the ski tie on the hillside and a measuring inducer ( , which are connected to a central unit consisting of logic and an input and output device. Device according to Claim 1, characterized in that in order to balance the amplifier (5) of the measuring induction loops, the checking induction loop (4) is arranged at right angles to the measuring induction loops (3) with a snow cover or a grass cover.