Four years of training for a competition, four years to optimize automatisms for one big goal: the Olympics. Starting processes are essential. Because a successful start often determines success and failure. With ski cross and ski jumping, two spectacular sports are currently at the start of the Olympic Games in Pyeongchang. In both disciplines, solutions from ACE shock absorbers are used at German and Austrian Olympic bases for start training.
Skicross is the BMX driving the winter games. Hard, spectacular and trendy. The fight man against man or woman against woman often decides already on the first meters. For overtaking maneuvers are anything but easy in the ski cross on demanding tracks full of steep turns and jumps. For this reason, the starting phase is rehearsed over and over again, especially in the summer months. In order to allow high repetition numbers in a minimum of time, there are for this purpose training devices, which remind of machines in fitness gyms.
Institute for Sports Science in Innsbruck
Such a device has also been manufactured by employees under the direction of Prof. Christian Raschner at the Institute for Sports Science in Innsbruck. After a planning phase, a first prototype was created that is visually reminiscent of a bed frame on castors. Instead of a slatted frame, a plate with ski bindings is attached in its center.
In addition, there is a slide that moves along the long sides and which rises a good meter on both sides. At its vertical end there are two handles with which the exercising skier can push the 36 kg sled backwards.
When test persons at the Institute of Sports Science Innsbruck first used the launcher, there were problems with the construction: First, the carriage raced with such a force into the end position that sooner or later damage was to be expected. On the other hand, during the first tests, a second person had to help with the holding, so that the training device did not become self-sufficient. At this point in the project, the ACE shock absorber GmbH from Langenfelde switched.
Damping elements provide a remedy for the starting training of skicrossers
As part of the technical consultation, the kinetic energy that must be absorbed by the two dampers was calculated in advance. For this, 8 m / s and 10 m / s were assumed as speeds. With a moving mass of 36 kg at 10 m / s, this resulted in support force values of approx. 38.000 N and in 8 m / s of approx. 25.000 N.
On the basis of this calculated energy, the sports scientist and trained machine fitter Mario Lazzeri, who mainly worked on this application at the Institute for Sports Science, selected two industrial shock absorbers of the type MA4575EUM to protect the end positions, each of which can absorb 1300 Nm per stroke and thus offers sufficient safety reserves. The requirements are not a problem for the construction elements belonging to the “Magnum” family. With a dead weight of 1,6 kg, they can reduce effective masses in a range from 70 to 15.000 kg and that with a piston reset time of just 0,11 s.
Normally used in automation, handling tasks or on rotary modules at home, these Magnum dampers now provide a stable training aid for skiers. Since the construction elements are equipped with the latest sealing technology, a hardened guide bearing and an integrated fixed stop, any number of training groups can work each day without the need for replacement after years of use. But should it ever happen, it can be done without any problems, because the shock absorber specialist provides its damping solutions with a large number of matching accessories and connecting parts.
Starting bar optimized for ski jumpers
The manufacturer's large selection of DIN-standardized accessories also proved to be an advantage for training on the ski jumps of the Hinterzarten ski club. The point here is to use the jumps one after the other and with a safe distance. The jump length must always be adapted to the capabilities of the jumpers and the prevailing weather conditions. If the wind blows z. B. from behind, ski jumpers are almost pushed into the slope, which leads to reduced widths.
Ballpoint pen principle makes the gas spring lockable on both sides
If the wind comes from the front, the athlete can use it as an air cushion to float far into the valley. If he gets into the critical area of the hill, where the landing hill is flatter, it becomes critical for the jumper. This is due to the fact that the flatter the landing hill, the steeper the angle for the jumper and the greater the forces acting on him during landing.
In order to achieve similar distances despite the different output powers and different wind conditions, the approach length and the resulting speed at the end of the take-off table serve as compensating elements. For this purpose, there are various start gates with four mobile start bars at the inrun tower in Hinterzarten.
These bars are mounted or plugged in during training at different starting gates, i.e. for different approach lengths. In the basic position, the bar arm is up. To start the approach, the jumper presses the beam arm down into the counter holder. If the jumper starts moving, the relieved beam arm is brought back into the basic position by gas pressure springs. The run-up is therefore for the next athlete who z. B. wants to start from a start bar mounted further above, quickly free again.
Training operations facilitated
This system makes training a lot easier, manual lifting or moving of the bars is no longer necessary. In this case, the solutions from ACE replaced products from another manufacturer that were too susceptible to damage. On the one hand, this was due to the fact that they were installed upside down, on the other hand, there was for them gas springs not enough accessories. At ACE, DIN-standardized accessories are part of the standard range. Due to the comparatively simple overall construction and in order to quickly put the training operation in good condition at the starting bar, the otherwise usual technically precise design including calculation was dispensed with and the weight of the bar was estimated. Two industrial gas springs of the type GS-22-200-EE-200N were then used per starting bar.
Easy operation of the start bar
The shock absorbers provide perfect support for hand power in hatches, lids, hoods or, as in this case, in the horizontally and vertically oriented take-off bars. The self-contained systems are filled with pressurized nitrogen gas and available in body diameters from 15 to 40 mm and with forces from 40 to 5000 N. The types for installation on the ski jump have a circumference of 22 mm and a stroke of 200 mm. The specified mileage of approx. 70.000 to 100.000 complete strokes is more than sufficient even for a brisk training operation.
With a dead weight of 415 g and a total length of 464 mm in the extended state, these ready-to-install, maintenance-free machine elements provide up to 1300 N push force. For the present application, however, they have been designed, filled, delivered and assembled with a 200 N extension force, which hardly requires athletes' muscular strength to close the launch bars and spares their energy from the bounce associated with great concentration, precision and power.
Whether jumped in winter or in summer, the ACE products perform reliably at temperatures from -20 ° to 80 ° C. The lower area appears only slightly dimensioned at first glance for a winter sport. Because at even lower temperatures, neither in Hinterzarten nor in Pyeongchang the training and competition operations take place.