Abstract: A process and device to detect and count yarn defects in a yarn segment including a camera (5), a computer (8) and an image processing program. The yarn (30) is illuminated with an intensity dependent upon the thickness of the yarn (30) and is photographed by the camera (5). The photographed image is digitalized in the computer with the image processing program and low-contrast points are filtered out. The remaining points are gathered together into coherent areas the sizes of which are classified into predetermined size classes and are stored.

Abstract: On a spinning machine, especially an open-end spinning machine, which has a plurality of spinning units (10) each with a plurality of elements (4, 41) to be controlled electrically, there is a maintenance device (2) which is movable along the machine and which can be coupled electrically to the elements (4, 41) to be controlled of the particular spinning unit (10) located in its working range. One bus line (51, 52) is provided for identical elements (4, 41) to be controlled electrically of each of a plurality of spinning units (10). Furthermore, each spinning unit (10) has a switching device (55) which can be actuated as a function of the posiiton of the maintenance device (2) and which connects the various elements (4, 41) to be controlled electrically of a spinning unit (10) to the bus lines (51, 52) which are assigned to them and to which the maintenance device (2) is constantly connected.

Abstract: A method and apparatus of detecting faulty operations of spinning units of an open-end spinning machine by monitoring the faults appearing in the yarn being produced by the machine and generating a fault signal responsive thereto. Another speed responsive signal is produced responsive to the speed that the yarn is being delivered from the spinning compartment of the machine. The fault signal is fed to a variable gain amplifier which has its gain controlled by the speed responsive signal. The signal produced by the amplifier is then differentiated, shaped, and integrated. The integrated signal is, in turn, compared with a threshold value for determining when the faults in the yarn exceed a predetermined level.

Abstract: A method and apparatus for detecting the faulty working of spinning units of an open-end spinning machine by monitoring the faults in yarn as it is fed from the spinning machine. An electrical signal is produced by a sensor indicating faults appearing in the yarn. Another signal of predetermined frequency corresponding to the speed of delivery of the yarn from the spinning machines is generated. The electrical signal produced by the sensor is electrically multiplied by the signal of predetermined frequency for producing a differential signal. This differential signal is filtered, shaped and integrated and subsequently compared with a preset threshold value for producing a signal indicating when the occurrence of faults exceed a predetermined threshold. This signal can be used for stopping the spinning unit.

Abstract: A method and apparatus for monitoring the production of spun yarn in an open end rotor spinning machine. The spun yarn is withdrawn from the open end rotor spinning machine at a constant rate of speed. As a result of changes in mass of the yarn created by flaws therein, the centrifugal force within the rotor varies causing the tension in the yarn to vary accordingly. As the yarn is withdrawn from the rotor, it passes around a spring loaded arm which is displaced according to the centrifugal force applied to the yarn. The spring loaded arm is operately connected to a balance bridge circuit which generates an output signal corresponding to the displacement thereof. The output signal from the balance circuit is then fed to an integrator which integrates the signal to produce a slowly varying integrated reference signal.