SATRA STM 156 Heel fatigue tester
Some high heels are prone to fatigue under the repeated small deformations produced by each step in walking. This machine is designed to check the fatigue resistance of such heels by subjecting them to continuous small impacts which produce similar deformations to those of wear. It is now a well established and valuable test.
The heel is held rigid at the seat in a fusible alloy in one of three special holders provided. A melting pot STM 156MP is required to melt the fusible alloy prior to pouring the alloy around the heel seat.
Adjustments are provided so that the heel, whatever its size or shape, can be set to receive forward impacts at the back of the stem, 6mm from the tip and perpendicular to the stem direction.
The standard impacts of 0.68 joules are delivered at one second intervals by a striker attached to a free falling pendulum. This is lifted mechanically between each drop and automatically caught on the rebound. When the heel breaks, the machine switches off automatically and a counter indicates the number of blows to cause failure.