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| Illustration 1 | g01420144 |
Vibratory Eccentric Weights (Cross Section) (1) Eccentric weights (2) Shot (3) Drum motor (4) Coupling shaft (5) Vibratory shaft | |
The drum assembly contains two eccentric weights. The eccentric weights are connected to individual splined shafts. The vibratory motor is splined to the shaft of the right eccentric weight, and the shafts of the right and left eccentric weights are connected by a coupling shaft.
When the vibratory system is operating, the vibratory motor rotates the eccentric weights by rotating the splined shafts. Since the center of gravity of the eccentric weights is not at the center of the shafts, rotation of the eccentric weights causes the drum to vibrate.
On standard machines, the speed of the vibratory motor is fixed. Therefore, the frequency of vibration is fixed. On machines that are equipped with the optional vibratory system, the speed of the vibratory motor can be varied. Therefore, the frequency of vibration can be changed. While the frequency of the vibration depends on the speed of rotation, the amplitude of the vibration depends on the direction of rotation of the eccentric weights. Both vibratory systems can produce two levels of amplitude.
The eccentric weights are partially filled with shot. When the vibratory system is operating at low amplitude, the motor rotates the shafts so that the shot is captured in the pocket on the light side of the eccentric weights. This action brings the center of gravity of the weights closer to the center of the splined shafts. As a result, the amplitude of the vibration is reduced.
When the vibratory system is operating at high amplitude, the motor rotates the shafts so that the shot is captured in the pocket on the heavy side of the eccentric weights. This action moves the center of gravity of the weights farther from the center of the splined shafts. As a result, the amplitude of the vibration is increased.