COVER ASSEM. 9K9116 - Caterpillar

Illustration 1 g01423839
Cross section of vibratory drum (A) Low amplitude (B) High amplitude (1) Eccentric weights (2) Shot (3) Eccentric weight (4) Eccentric weight (5) Shot (6) Vibratory motor (7) Coupling shaft (8) Drum motorThe 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 which 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 and reducing the amplitude of the vibration.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 takes the center of gravity of the weights farther from the center of the splined shafts and increasing the amplitude of the vibration.