Abstract: An optical apparatus for producing a light curtain using a fibre optic rod with a sawtooth mirror disposed along the face away from the curtain area.

Abstract: Optical multiple-reflection arrangement comprising a light source, a lens separated from the source by its focal length in front of a retroreflector which returns a laterally offset beam, deflection means to displace the reflected image to one side of the source, and a second retroreflector near the image, whereby the measurement path between the retroreflectors is traversed at least four times by a beam from the source.

Abstract: A photoelectronic instrument for measuring the length of an object by means of a slim scanning beam of light which, when not interrupted by the object, activates a photoelectric transducer, wherein, for the purpose of determining trigger points when half the light beam is obscured at the beginning and reemerges at the end of the period of cut-off, irrespective of the absolute magnitude of the light flux of the unobscured light beam, a circuit is provided for differentiating, with respect to time, a signal obtained from the photoelectric transducer and proportional to the magnitude of the light flux (light flux signal U.sub.1), a signal proportional to the differential quotient (dU.sub.1 /dt) thus obtained being rectified, multiplied by a preset factor (p.T), and the product of the multiplication and the light flux signal (U.sub.1) being applied to the inputs of a comparator functioning as a coincidence circuit for generating an output signal (U.sub.

Abstract: The pitch of twisted threads are measured by illuminating the threads with monochromatic light, especially a laser, to throw on a receiving surface a diffraction image from which the pitch is evaluated, preferably automatically by optical scanning and computing.

Abstract: A curve tracer comprising: an optical tracer head for scanning a line having at least a substantial transverse component and at least one marking on the line, with a predetermined scanning speed. The head is moved along the line at a speed substantially lower than the scanning speed. There is a control unit for controlling the movement including an integrator, means for feeding the integrator with a voltage proportional to the speed of the tracer head, and means for supplying a signal proportional to the distance travelled by the tracer head when the head moves over the marking.

Abstract: A method of measuring the pitch angle of yarns provided with a twist, characterized in that an image of the surface of the thread is cast onto a slitted shutter, the slitted shutter and the thread are rotatable relatively to each other about their connecting axis and that the intensity of the light passing through the slitted shutter is measured as a function of the relative angle of rotation between thread and slitted shutter.

Abstract: A reading device for optically detectable digital codes with two different light-reflecting types of fields. It comprises: a scanning beam arrangement having a timing raster with two different light-reflecting types of serially-numbered fields, means for conducting part of the scanning beam via said timing raster and the rest onto the code fields, a timing signal photoelectric cell receiving the light reflected back by the timing raster, a coding signal photoelectric cell receiving the light reflected back from the code field, and an evaluation electronic system connected to the outputs of the photoelectric cells for determining the length of the code fields in units of the timing raster in the scanning direction. Each code field length is associated with a number of timing fields varying between two predetermined limits.

Abstract: Apparatus and method for reading light-dark or color-contrast codes on articles which are displaced over a light-transmitting region of a support of the kind wherein a scanning light beam is directed onto the articles and scattered light reflected from the articles and codes is supplied to a photoelectric transducer the output signal from which is supplied to electronic evaluating means, wherein the scanning light beam is directed upwardly through the light-transmitting region of the support and is displaced along two imaginary straight lines located in the light-transmitting region of the support, said lines, which preferably intersect, extending obliquely to the direction of displacement of the articles and substantially at right angles to one another.

Abstract: A coding strip for attachment to a container which is routed to one of several destinations defined by a machine readable code thereon including a support member having a circular cross-sectional rail upon which a slide member is mounted for longitudinal movement along the rail. A spring is mounted on the slide and engaging the support member for urging the slide into a locking position in which ribs on the support member block longitudinal movement. The slide member can be moved by pivoting into a position in which the slide slips by the ribs.

Abstract: Apparatus for the continuous monitoring of the condition of the needle heads of a circular knitting machine which move past a predetermined point one after the other at a definite frequency comprising an illuminating component for producing a light spot in the form of a line situated in the plane of an illuminated needle head without light projecting laterally beyond it, said light spot being projected into an aperture substantially the size of the image of the light spot, a photo-receiver disposed behind said aperture and adapted to emit an electrical pulse signal in proportion to the luminous flux passing through the aperture, and a threshold value electronic device for receiving said signal, which when a pulse falls below a predetermined value and/or when there is a change in the predetermined time spacing of two successive pulses, delivers a warning signal.