GB1451174A - Oscillation exciters - Google Patents

Abstract

1451174 Vibratory roller KOEHRING GmbH-BOMAG DIVISION 26 June 1974 [25 July 1973] 28360/74 Heading A1B [Also in Division F2] A vibration generator for use for example in vibratory ground rollers comprises at least one rotatably mounted container, the interior of which is divided into two chambers, means for rotating the container, and means for injecting liquid selectively into either one of the chambers and means for venting from the other chamber an equal quantity of liquid as it is injected into the one chamber while the container is rotated to adjust the liquid contents of the two chambers relatively to each other to cause the container and liquid contained in its chambers to form an unbalanced mass, the imbalance of which can be increased or decreased without stopping rotation of the container. In the embodiment shown in Figs. 3 and 4, a hollow rotary shaft 1 of a vibratory ground roller is surrounded by a cylinder 30 containing a rotary-vane piston 20 rotatable on the shaft 1. The piston 20 can if desired be connected to the cylinder 30 through a torsion spring (not shown). The rotary vane of piston 20 projects radially outwards from a bush rotatably mounted on the shaft 1 and into outer end slides over the inner surface of the cylinder 30, while a stationary vane projects radially inwards from the inner surface of the cylinder 30 and its inner end slides over the outer surface of the bush. The two vanes between them form cylinder chambers A and B. When the vanes are as shown in Fig. 3, their masses counterbalance each other. In order to form an out-of-balance mass liquid is delivered to one of the chambers A or B and vented from the other to rotate the rotary vane, the greatest degree of unbalance being obtained when the two vanes are side by side in contact with each other. Liquid is supplied to the chambers A and B by a pump 21 through hydraulic lines 22, 23 respectively. and through other lines (not shown) forming a circuit which includes a control valve 24, housed within the shaft 1 alongside the pump 21. The valve 24 is actuated by a control spindle 25 coaxial within the shaft I and inside a hollow spindle 26 which drives the pump 21 through a gear train 28. Spindle 26 rotates in bearings in a connecting piece 27 mounted inside the shaft 1. When the pump 21 is operating, it delivers liquid through the valve 24, which liquid either flows through lines 22, 23 to one or other of the two cylinder chambers or returns to the hollow rotary shaft 1 which acts as a liquid reservoir. As the shaft 1 rotates the liquid distributes itself evenly over the inner surface of the shaft and is driven into the pump 21 through its inlet opening which is close to the inner surface of the shaft, by centrifugally developed pressure. In alternative embodiments, the rotatably mounted container is divided into two chambers by a reciprocative piston (Fig. 1, not shown) and by a fixed wall (Fig. 5, not shown).