US Patent 9903502 Fluid-operated drive

In a fluid-operated drive for a field device, the drive being designed to set a control valve of the field device, a fluidically operated basic drive is provided with a basic working chamber loaded fluidically and delimited by a basic drive housing part and by a basic actuating piston guided in the basic drive housing part. At least one supplementary drive is provided with a supplementary working chamber loaded fluidically and delimited by a supplementary drive housing part. The basic drive housing part and the supplementary drive housing part are displaceable in one another in accordance with a piston and chamber arrangement so that a volume of the supplementary chamber changes in the event of a relative movement of the drive housing parts.