Abstract: To provide a more representative output signal on electro-optical transducers scanning a traveling filament, such as a textile thread than heretofore possible, a beam of light is passed to the filament and the light reflected therefrom is analyzed and transduced into an electrical signal, so that light passing laterally of the filament is eliminated from the pick-up to provide an output signal in the pick-up representative only of the portion of the thread which is actually illuminated.

Abstract: To prevent periodically recurring thickened portions of thread from open end spinning machines, a thread thickness sensing signal is conducted to a mono stable blocking multivibrator having an unstable blocked time just under, for example, ninety percent, of the time of pull off of thread during one revolution of the turbine, so that the distance of thread passing through the sensor during the unstable time is just slightly less than the circumference of the spinning turbine of the open end spinning machine. If other thickened portions result from a specific circumferential point of the turbine, resulting in periodic defects, the mono stable multivibrator will be triggered again and again; the trigger signals is summed, for example, by an integrator and if the sum of the pulses reach a certain value, a defect signal is generated, for example, stopping the machine. Before being applied to the mono stable multivibrator, the signals are preferably dynamically limited.

Abstract: To provide a readily separable electrical in-line connection in which mechanical stress on the terminal itself is relieved, one terminal strip or lug, in a flat strip form, is engaged by another terminal lug having a bent-over tab, so that, in cross section, the other terminal element is U-shaped; one of the terminal elements has a hole punched into it, and the other has a projecting pin, fitting into the hole. The two terminal elements are assembled together by inserting the pin in the hole, with the terminal elements respectively aligned at a slight angle, and they are then rotated so that the U-shaped bent-over tab engages around the other terminal element, to make a secure electrical connection which is also mechanically stable.

Abstract: A pair of pressure disks through which the thread may pass are pressed together by a controllable electromagnetic force generated by a pressure electromagnet acting on at least one of the disks. The thread is passed over an oscillating lever which is urged by the tension of the thread from a first position to a deflected position and, when in the deflected position, closing an electrical contact which opens the circuit to the pressure electromagnet acting on the disks to return the lever to the first position, thus opening the contact. The magnetic force of a lever reset magnet is adjustable.

Abstract: A sensing lever, preferably a double-arm lever, is journalled over a fulcrum; one arm is engaged by the thread to be supervised, and further connected to operate an electrical switch; the other arm is subject to electromagnetic force derived from an interrupted, pulsed electromagnet. Pulsed operation of the electromagnet can be obtained by a signal derived from the switch of the lever itself, or from an extraneous source; upon attraction by the magnet, the contacts are opened; during a pulse gap, the thread tension depresses the lever, thus closing the contacts; the lever will, therefore, continuously vibrate and presence of an a-c signal across the switches will be indicative of: (a) presence of thread; (b) thread tension below a predetermined limit (excessive tension would overcome the pulsed reset force of the electromagnet); and (c) proper operation (jamming of the lever would likewise result in a d-c output from the switch).