Abstract: The invention relates to a compensation cylinder unit that acts as a drive for the electrode arms of a welding device. The unit comprises a cylinder and at least two pressure chambers, which are sub-divided by a piston assembly and which can be alternately supplied with a pressurized medium by means of a valve assembly for controlling the drive displacement. According to the invention, the valve assembly comprises a proportional valve which can be controlled by a control unit, first in accordance with harmonized path signals that represent the position of the piston assembly and then by pressure signals that respectively represent the pressure in the pressure chambers, in such a way that the difference between the pressures that prevail in the pressure chambers in a predeterminable position of the piston assembly assumes a constant value that represents the weight compensation force of at least one electrode arm.

Abstract: A method for balancing an electrode arm (101) of a welding device (100) is provided. The welding device (100) includes a first electrode arm (101) and a second electrode arm (102) movable with respect to one another and coupled to a reference arm (30). The welding device (100) also includes a compensation actuator (106) coupled to the first electrode arm (101) and to the reference arm (30) to balance a weight of the first electrode arm (101) and including first and second fluid chambers. The method comprises a step of adjusting a differential pressure between the first and second fluid chambers of the compensation actuator (106). The method further comprises a step of determining a differential balance pressure required to balance the weight of the first electrode arm (101) when the first electrode arm (101) moves by more than a threshold amount.

Abstract: The invention relates to a compensation cylinder unit that acts as a drive for the electrode arms of a welding device. The unit comprises a cylinder and at least two pressure chambers, which are sub-divided by a piston assembly and which can be alternately supplied with a pressurized medium by means of a valve assembly for controlling the drive displacement. According to the invention, the valve assembly comprises a proportional valve which can be controlled by a control unit, first in accordance with harmonized path signals that represent the position of the piston assembly and then by pressure signals that respectively represent the pressure in the pressure chambers, in such a way that the difference between the pressures that prevail in the pressure chambers in a predeterminable position of the piston assembly assumes a constant value that represents the weight compensation force of at least one electrode arm.