Resistance Under Stress Coefficient
Spiderfrog is an innovative measuring device, certified
in Germany by Staatliche Materialprüfungsanstalt (MPA
), Darmstadt, company credited by DaKKs. Spiderfrog has been especially designed by Giuliano Group
in order to check and measure bending and torsion of tyre changers' main parts under stress, which typically occurs during tyre mounting/demounting operations.
Such a stress is determined by a combination of forces which are normally activated during tyre
rotation, when the tyre changer's operating arm is engaged and working with tyre and rim, to mount
and/or demount the tyre bead over the rim:
- A Tangent Force, left-to-right or right-to-left;
- A Radial Force, front-to-back and back-to-front;
- A Vertical Force, up-down.
Through the SPIDERFROG device we have found an interesting way to measure
combine them in a calculated “Combination Force”, and find a “Resistance Under Stress Coefficient
), which gives some idea of how robust a tyre changer can be
, in terms of strength and power against all different kinds of stress involved in mounting/demounting tyres.