The instrument (Fig. 123) is constituted by the pendulum 1. The pendulum is fixed to the metal plate 2 with a round metal machine (silver wire) with a diameter of 3 mm. The plate is again placed on two steel balls 3 with a diameter of 8 mm.
Ball is supported on the fixed platform of support 4. The brackets are in turn embedded in the wall. A movable Chinese circular scale 6 is installed under the pendulum needle 5, and its Chinese diameter is equal to the length of the pendulum (from the fulcrum of the ball to the tip). The scale is divided into several divisions.
The brackets are in turn embedded in the wall. A movable Chinese circular scale 6 is installed under the pendulum needle 5, and its Chinese diameter is equal to the length of the pendulum (from the fulcrum of the ball to the tip). The scale is divided into several divisions.
When using the pendulum Tester to measure the hardness of the paint film, place the glass plate 7 coated with the sample on the platform of the instrument so that the paint film faces upward and carefully place the pendulum on it. Thereafter, move the scale so that its zero degree is aligned with the pointer of the pendulum. Then, lead the pendulum to an angle of 5 degrees and release it, and start the stopwatch while releasing the pendulum. Stop the stopwatch when the amplitude of the pendulum vibration decreases to 2 degrees. The time required for the amplitude of the hammer to decrease from 5 degrees to 2 degrees can be used as the hardness of the paint film. (Related instrument: Hardness Tester)
Orlov pointed out that the lack of equipment capable of simultaneously starting the stroke hammer and the stopwatch, and the inevitable deformation of the paint film under the ball before starting the hardness measurement, are the shortcomings of the HNNJIK pendulum Tester.
In order to improve these shortcomings, the MXTH Paint Technology Teaching and Research Office named after Mendeleinav adopted a balance-stabilized stabilizing device, which improved the structure of the HNNJIK pendulum Tester. The pendulum is placed in a wooden list in the form of an analytical balance list.
Figure 124 shows a sketch of the pendulum construction. The structure of the stabilizer can be clearly seen from the figure.
Later, when improving the structure of the HNNJIK pendulum measuring device, THNN-4 also considered the principle of stability.
In order to accurately measure the moment of vibration termination, Lashou Lliefu and Oster Lin proposed a device for automatically recording the vibration time of the HNNJIK pendulum. But this device was not adopted.
