Abstract: Photoelectric sensing apparatus is operative for sensing the absence of filament at a particular point on a supply bobbin wherein several strands of filament will still be present on the bobbin. The sensing apparatus includes a light source which directs an angled photoelectric beam at a sensing point near the center of the bobbin and a light sensor which detects reverse reflections of the beam. If there is filament present at the sensing point, the beam will reversely defect off the round surface of the filament back to the light sensor. If there is no filament present at the sensing point, the beam deflects off the exposed core of the bobbin away from the light sensor in a different direction. Electronics means are provided which cooperate with the sensing apparatus to automatically shut-down the machine pursuant to absence of filament at said sensing point.

Abstract: The presence of residual yarn on textile bobbins is recognized by a device capable of optically sensing and distinguishing yarn from a supporting bobbin or tube, which device is movable lengthwise along the bobbin or tube to perform a sensing operation. The sensing device includes a light source, a transmitter lens for focusing the light rays onto the surface of the bobbin, and a photooptic detector having a receiver lens for receiving the light rays reflected off the bobbin surface. The transmitter and receiver lenses have respective optical axes which, during sensing movement, are oriented to intersect one another at the bobbin surface, are oriented relative to the bobbin such that a line bisecting the axes deviates from a line intersecting the vertex of the axes perpendicular to the bobbin surface by at least ten degrees (10.degree.), and also lie in a common plane oriented at an angle of at least about ninety degrees (90.degree.) relative to the path of movement of the sensing device.

Abstract: A yarn storing device (1) comprises a storage drum (2) and a sensor (5) arranged at the withdrawal end (3) of the storage drum (2). The sensor (5) has the form of an eyelet (6) for guiding the yarn (4) and generates a signal during the withdrawal of yarn (4) having a frequency corresponding to the number of turns of yarn withdrawn per time unit. For enhancing the reliability of detecting the withdrawal of yarn on the basis of the sensor signal, the eyelet (6) of the sensor (5) is movably mounted on a housing (7) of the sensor (5) and comprises a light-reflecting surface (11) wherein a light-emitting element (8) and a light-receiving element (9) are fixed to the housing (7) such that the light generated by the light-emitting element (8) falls on the light reflecting surface (11) and is directed towards the light-receiving element (9) when the eyelet (6) has a predetermined relative position with respect to the housing (7).

Abstract: A photoelectrical bobbin feeler, in particular weft bobbin feeler, comprises one light source and two light sensors, or vice versa, two light sources and one light sensor. At least one polaroid filter is arranged in front of the one light source, or one light sensor, respectively, for polarizing the light which is specularly as well as diffusely reflected from the bobbin, and provides for a safer detection of the "bobbin empty" condition.

Abstract: A thread monitoring device for monitoring the thread supply in a sewing machine, having a rotary hook, comprises, a hook body with a thread bobbin having thread thereon which is connected to a rotatable shaft for rotation thereby. The hook includes a stationary bobbin case which is enclosed by a hook body which has a hub portion connected to the shaft. A light source is disposed on one side of the hook and a light receiver is disposed on the opposite side. Light is transmitted by the light source through a path intercepting the thread on the bobbin so that, when the thread on the bobbin is paid out during the stitching operation, beyond a predetermined amount, the light will be transmitted to a reflective wall portion of the hook body and deflected by the wall portion to the light receiver. The light receiver is connected in a control circuit to operate a control for operating the sewing machine or for actuating an indicator to show that the thread has been used up to the predetermined amount.

Abstract: An optoelectrical filling or weft bobbin feeler on a shuttle weaving machine, provided with a light source and a light sensor located in a casing which comprises at least one wall mounted in parallel relationship to the shuttle race. Light source and light sensor are arranged in the casing such that the optical axes define a plane forming a small acute angle with said one wall of the casing. Such a bobbin feeler functions to stop the loom in the instant when the thread winding on the bobbin runs out.

Abstract: The present invention relates in general to yarn processing and in particular to a method and apparatus for detecting unwanted yarn wraps on rotating rolls and consequently severing the supply yarn to prevent further wraps being wound.

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.