A flexible hose tensioning device includes a shaper roller for receiving a flexible hose. The shaper roller includes guide grooves, into which raised sections of the flexible hose engage. The shaper roller and the guide grooves are configured so that there is a form fit between the shaper roller and the flexible hose. An element that holds the flexible hose in the shaper roller and a spring coupled to the shaper roller are also provided. The spring is tensioned when the flexible hose is pulled in a corresponding direction and generates an opposing force to a flexible hose tensile force.