The University of Michigan’s new athletic facility features a hydraulically operated running track that can be elevated and banked. To create the track, Beynon Sports Surfaces, a manufacturer of athletic surfaces and indoor running tracks, went to long-time partner, Mitchell Machine Works. MMW is responsible for creating the hydraulics system that adjusts the shape of Beynon tracks.
The Rise-N-Run system, as it is called, allows the track’s running surface to be altered using 80 hydraulic cylinders controlled with a programmable HMI. Having worked on tracks for Beynon in the past, MMW understood the basic needs of system. But every new track has some inherent challenges. With this level of movement, there are bound to be torsional deflection challenges.
“Accounting for the stresses, torsional deflections, and overall movement of the individual segments were the biggest initial challenges,” said MMW CEO, Mark Mitchell.
When a segment of the track moves, the outer perimeter can be reduced by at least 12-in. and each individual section will move roughly 3/16 of an inch depending on the track.
“If we change the radius of the turn, then there’s a slight movement to deal with in terms of how much torsional deflection there will be in the frames themselves. They actually have to twist so we have to allow them to twist under load or under stress. Additionally, of course, it also has to move, so it still has to extend and retract as it supports those loads,” added Mitchell.
MMW took its model and then positioned it in various spots while it was inclining from zero to 10 ° to put it through all of its movements and see how much everything moves on a small scale before creating the actual track. After this, MMW used its in-house, Financial Element Analysis (FEA) that shows where the stresses are during the moving process. The FEA then points out hotspots and the MMW team makes sure sufficient material is there to carry the load, and deflect without creating an increase in additional forces.
Another challenge was stability. The track does not require much pressure to be raised. However, holding it in place is a critical part of the system. If one cylinder fails or comes under duress, it won’t just sink down, it will cause significant structural damage within the system.
To monitor this, MMW uses what they call a “live positioning system.” The motion control is always active. It’s always monitoring, and should any component get more than its 10 millimeters out of position, even if it has been up for weeks, the system sends an alert to fix the problem. The track is always being monitored.
Mitchell Machine Works
Filed Under: Cylinders & Actuators, News