Variable mechanical vibrator

A rotating vibrator including in combination:

• a rotatably mounted shaft;
• first eccentric weight means on said shaft for rotation therewith;
• a rotational mass including a second eccentric weight means disposed about the axis of said shaft and mounted for free concentric rotation about said shaft;
• driving means coupled with at least one of said shaft and said rotational mass for changing the rotational speed of said vibrator, whereby the other of said shaft and said rotational mass comprises an inertia mass;
• stop means attached to one of said shaft and said rotational mass for limiting the relative rotation of said shaft and said rotational mass between first and second relative rotational positions;
• and
• engagement means coupled with the other of said shaft and said rotational mass for engaging said stop means in said first and second relative rotational positions;
• such that in said first relative rotational position, said first and second weight means are located on diametrically opposite sides of said shaft to balance the vibrator when said driving means is decelerating, and in said second relative rotational position said first and second weight means are located on the same side of said shaft to unbalance the vibrator, with said stop means located so that said first and second weight means are locked into said second position solely by means of forces caused by rotation when said driving means is increasing or maintaining constant the rotational speed of said vibrator.

A variable vibrator including in combination:

• a rotatably mounted shaft;
• first eccentric weight means carried by a hollow drum fixedly attached to said shaft and having a channel therein with first and second stops located in said channel;
• second eccentric weight means comprising a cylindrically shaped weight located within said channel for free movement therein between a first rotational position, with said first and second weight means being diametrically oppositely aligned with respect to said shaft, and a second rotational position different from said first rotational position as determined by the location of said first and second stops, said second rotational position being such that the center of gravity of said first weight means is a predetermined number of degrees ahead of the center of gravity of said second weight means in such position in the direction of rotation of said shaft when a constant rotational speed is reached and maintained by said drum and shaft;
• and
• means for abruptly effecting changes in the relative speeds of rotation of said first and second weight means while said shaft is continuously rotating to effect changes in the relative rotational positions of said first and second eccentric weight means between said first rotational position and said second rotational position.

A rotating vibrator including in combination;

• a rotatably mounted shaft;
• first eccentric weight means on said shaft for rotation therewith;
• a rotational mass including a second eccentric weight means disposed about the axis of said shaft and mounted for free concentric rotation about said shaft, said second eccentric weight means having the same vibratory mass as said first eccentric weight means;
• means coupled with at least one of said shaft and said rotational mass for changing the rotational speed of said vibrator, whereby the other of said shaft and said rotational mass comprises an inertia mass;
• stop means attached to one of said shaft and said rotational mass for limiting the relative rotation of said shaft and said rotational mass between first and second relative rotational positions;
• and
• engagement means coupled with the other of said shaft and said rotational mass for engaging said stop means in said first and second relative rotational positions, such that in said first relative rotational position said first and second weight means are located on diametrically opposite sides of said shaft to balance the vibrator, and in said second relative rotational position said first and second weight means are located on the same side of said shaft to unbalance the vibrator, with the one of said first and second weight means which when driven tends to rotate faster than the other of said weight means being located relative to said stop means such that in said second rotational position said one weight means, which is the driven weight means, has a center of gravity a predetermined number of degrees ahead of the center of gravity of the other of said first and second weight means in the direction of rotation of said shaft to lock said first and second weight means into said second position solely by means of rotational forces when a constant rotational speed is reached and maintained.