Abstract: The invention relates to a pram or pram frame comprising a pusher bar for pushing the pram or pram frame and at least one force sensor device for detecting a direction or a magnitude of a force or a force component acting on the pusher bar and for detecting a variable derived from said force or force component, in particular a change in the force or force component over time, wherein the at least one force sensor device is designed to measure a force (component) or a variable derived therefrom at least over a vast majority of a horizontal section of the pusher bar, and is designed to measure a force (component) or a variable derived therefrom in at least one, in particular curved or arcuate, transition section of the pusher bar between the horizontal section of the pusher bar and a connecting section of the pusher bar.

Abstract: The invention solves the problem of ejecting impurities out of a cleaning aperture in the fiber separating device of an open-end rotor spinning unit, particularly when there are various contaminations of fibrous slivers and of different kinds of textile fibers being processed. For this purpose an air flow regulator is provided in the separating device in an air supply duct communicating with the cleaning aperture. According to the invention, the air flow regulator is provided with an air directing wall near the outlet of the air supply duct and thus directs air flow into the cleaning aperture toward the fiber opening cylinder.