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US 4,240,326 AGranted
Hydraulic vibration exciter and method of cooling thereof
AssigneeKoehring GmbH - Bomag Division
InventorUdo Carle
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AssigneeKoehring GmbH - Bomag Division
InventorUdo Carle
Estimating the term…
A hydraulically operated vibration exciter for a vibrating compactor of the kind comprising a piston in a cylinder, the piston and cylinder being arranged to move to and fro relative to each other, a source of liquid under pressure, a pressure line connecting the source to the cylinder and means for causing the liquid to move to and fro between the source and the cylinder to bring about the relative movement between the piston and cylinder is cooled by a method in which, during the relative movement, a quantity of the liquid is withdrawn from the cylinder and this quantity is not returned to the cylinder in the subsequent stroke, but is replaced by a fresh quantity of liquid at a lower temperature. To enable this cooling method to be carried out, an exciter of the kind just described is provided with a duct which leads from at least one of the end faces of the piston to an opening in the peripheral face of the piston, and the cylinder is provided with an opening in its wall with which the opening in the peripheral face of the piston comes into communication intermittently during the to and fro relative movement, the opening in the wall of the cylinder being connected by a liquid withdrawal line to a liquid reservoir.
In a hydraulically operated vibration exciter for a vibratory compactor, which exciter includes a cylinder, a piston mounted in the cylinder for reciprocating movement therein and delimiting two cylinder chambers located at respectively opposite sides of the piston, a source of hydraulic fluid under pressure communicating with the chambers for causing a liquid column of variable volume to move to and fro between the source and each chamber, the source acting to produce a cyclic reversal in the direction of liquid flow between the source and each chamber and a cyclic variation in the pressure of the liquid between the source and each chamber, for causing the piston to undergo, relative to the cylinder, a reciprocating movement with a controllable stroke, the improvement comprising means for discharging from each chamber a quantity of heated hydraulic fluid proportional to the pressure in said chamber only when said piston is in the vicinity of the center of its stroke;
A method of cooling a hydraulically operated vibration exciter for a vibratory compactor, which exciter includes a cylinder, a piston mounted in the cylinder for reciprocating movement therein and delimiting two cylinder chambers located at respectively opposite sides of the piston, a source of hydraulic fluid under pressure communicating with the chambers for causing a liquid column of variable volume to move to and fro between the source and each chamber, the source acting to produce a cyclic reversal in the direction of liquid flow between the source and each chamber and a cyclic variation in the pressure of the liquid between the source and each chamber, for causing the piston to undergo, relative to the cylinder, a reciprocating movement with a controllable stroke, said method comprising discharging from each chamber a quantity of heated hydraulic fluid proportional to the presence in said chamber only when said piston is in the vicinity of the center of its stroke;
Dependencies are inferred from the claim text.