“The entire sensor system in a shoe – that was really inconceivable!”
The days of the foot switch are over! From now on, press brakes made by TRUMPF can be actuated simply by using a special shoe. Klemens Freudenthaler developed it and tells us how it came about.
Where did the idea for the MagicShoe come from?
The position of the foot when operating a tethered switch is not very ergonomic. Movingthe pedal around all the time is inefficient and annoying — especially when executing sequences of bending operations. This is why — during the preliminary development stages — we asked ourselves how the entire stroke release process might be made more convenient and efficient. The team developed and evaluated all kinds of ideas during the brainstorming phase. We ultimately came to the conclusion that the stroke would have to be triggered by the operator’s foot, since the hands are always busy positioning and holding the sheet metal component. From today’s viewpoint, the only really logical step was to “simply” integrate all the foot pedal functions into a shoe. However, when we came up with this idea it was hard to imagine it could be realized, given the strict safety requirements in force.
Which criteria did the shoe have to fulfill?
The safety requirements for such a system are very tight, as was mentioned. Since the MagicShoe communicates wirelessly with the press brake, the interface has to meet the same high safety standards. Additionally, we had to ensure that the operator was inside the machine’s operating range when actuating it with the MagicShoe. Neither could the machine ever be tripped by accident. This meant that the operator’s foot movement to start the bending process had to be as safe and unequivocal as possible. Finally, the MagicShoe had to be as comfortable as a standard safety shoe.
What were the stumbling blocks?
The greatest challenge by far was finding a motion pattern that the operator could perform as easily and comfortably as possible and that nevertheless fulfilled all the safety requirements. The second difficult task was designing the mechanical elements for the sensor system built into the shoe. We were entering uncharted terrain and first had to gather knowledge in this regard.
How did you manage that?
The basic idea for the release pattern was worked out in trials on ourselves in the office. We then tried it out and refined it, working with colleagues from our in-house metal shop. The goal was to examine ergonomics and efficiency under production conditions. During this period we never failedto consider whether the release pattern was indeed safe. Under no circumstances could it be possible to actuate the press brake by accident. At one point the team collected measurement data for the routine foot movement patterns of 40 test persons. The team investigated these after each development step to make sure that the new triggering motion was not among these movements. The release pattern fulfils the safety requirements only if it is not contained in the measurement data.
What makes you especially proud of the MagicShoe?
The fact that I am responsible for having developed one of the first “wearable” products in mechanical engineering — one that underlines TRUMPF’s innovation leadership.
Contact us: MastersofSheetMetal@trumpf.com
This article was first published in autumn 2014.