Yo-Yo Ball Tester

The GT-MB19 yo-yo ball tester is utilized for the measurement of initial length l0 and elastic constant k of yo-yo balls, and the toy safety testing equipment is compliant with EN-71-1 8.37.

Yo-Yo Ball Initial Length Measurement
Apply a mass of 0.05±0.001kg to the ring at the end of the tether made of elastic material, and then measure the initial length l0 in millimeters to an accuracy of ±1mm.

Yo-Yo Ball Elastic Constant Measurement
1. Attach a fixed clamping device to the yo-yo ball tether 15±5mm from the ball. Then, position the tether vertically and attach a free clamping device to the tether at a distance of 15±5mm from the ring at the end of tether.

2. Apply a mass (including the mass of the free clamping device) of 0.1±0.005kg to the free clamping device parallel to the axis of the tether and measure the distance L1 between the two clamps in millimeters to an accuracy of ±1mm.

3. Remove the force and allow the tether to relax to its approximately original length.

4. Apply a mass (including the mass of the free clamping device) of 0.2±0.005kg to the free clamping device parallel to the axis of the tether and measure the distance L2 between the two clamps in millimeters to an accuracy of ±1mm.

5. Calculate the elastic constant k as the following equation: k=1000/(L2-L1)