Abstract: The invention relates to a device for producing images of a layer of a three-dimensional object, with radiation sources arranged in a radiation source plane, for irradiating the object with beams of rays from different directions, and with several planar recording layers, arranged parallel to one another, of recording all said shadow images, wherein before each recording layer there is arranged a diaphragm arrangement that has been allocated to it for (stepwise) masking of the beams of rays, and wherein the diaphragm apertures of each diaphragm arrangement are so much the smaller, the greater the distance the diaphragm arrangement is from the radiation sources.

Abstract: A method of and a device for the coding and decoding of an object by means of point-shaped radiation sources. The point sources are subdivided in groups which successively irradiate the object. Two sources distributions can be derived from the groups of radiation sources (a negative radiation intensity is assigned to at least one group), the sum of the autocorrelation functions thereof having the value "0" outside the origin. The coded images generated by means of the various groups are recorded (and also their negatives). Combinations of a coded image and a negative are decoded via point holograms or lens matrices, thus forming a subimage. The sum of all subimages forms an object image which is free of artefacts.

Abstract: A safety device for a power chain saw or the like. The safety device has a mass body which is responsive to acceleration forces and is operatively connected with a brake device. The mass body has at least one support part under a holding force, the mass body being displaceable from a rest position under the effect of the acceleration force (a "monostable inertia switch"). The mass body in a preferred embodiment is made as a bar or rod magnetically attracted to a supporting surface and capable of being tilted from an upright or vertical position temporarily into electrically conducting engagement with an annular ring spaced therefrom and surrounding the upper free end of the bar or rod, permitting electrical connection to be established to actuate a brake device for stopping the power chain saw in case of an emergency, including tripping, falling, slipping, or sudden shock, as a safety feature of an operator of the power chain saw.

Abstract: A device for imaging layers of the interior of a three-dimensional object. The object is irradiated from a large number of radiation source positions which are distributed in one plane from this, a coded image of the object which coded image consists of separate perspective images is produced. The coded image is illuminated and imaged by means of an imaging matrix whose imaging elements are distributed in the matrix plane according to the flat distribution of the radiation source positions. Layer images of the object are formed on a photosensitive element by the superposition of the perspective images. For forming different layer images of the object, the imaging elements are positioned in different distributions of changed scale with respect to the distribution of the radiation source positions.

Abstract: For the formation of layer images of a three-dimensional object, the object is irradiated from a large number of radiation source positions which are situated in one plane. Thus, a coded image of the object, consisting of individual perspective images, is formed. Subsequently, the coded image is illuminated and the perspective images thereof are superposed for the reconstruction of the object by means of a lens matrix which extends parallel to the plane of the coded image and whose flat lens distribution corresponds to the distribution of the radiation source positions. In the superposition zone of the perspective images, a photosensitive element is introduced in order to form individual layer images of the object. For the formation of the different layer images on the photosensitive element, the lens matrix is displaced in the direction of the optical axis, and the photosensitive element is positioned each time within the depth of focus range of the lenses of the lens matrix.

Abstract: A portable motor chain saw with a braking device, for stopping the saw chain during recoil, and with a release, for the braking device, which in the release position is operatively connected with a locking mechanism of the braking device. The release is an inertial mass which is freely movable along an acceleration path, with the kinetic energy of the inertial mass in the release position being greater than the resistance force of the locking mechanism. The release is held in the ready position by at least one holder, preferably a spring which extends between the saw housing and the release.

Abstract: Disclosed is a method of making an inverse filter wherein a single photographic plate is illuminated by the object and reference waves so as to expose the photographic material in the logarithmic portion of its transmittance versus illumination curve to thereby form a holographic image which upon development forms the inverse filter.

Abstract: A method of coding and decoding of objects by means of a large number of point-like radiation sources which are subdivided into two groups. Two recordings are made of an image object. A first recorded image is made on a first recording medium with a first radiation source distribution. A second recorded image is made with a second radiation source distribution which is determined by the autocorrelation function of the first distribution. In the second radiation source distribution, the source which is determined by a function value in the origin of the autocorrelation function is omitted. In a first decoding step, the first recorded image is decoded with a point image function of the first radiation source distribution. In the second decoding step, the second recording is subtracted from the decoded first recorded image, so that an artifact-free image of the object is produced.

Abstract: A drive mechanism for a rotary drum having a toothed ring which is disposed on the outer periphery thereof with a clearance in relation to the drum and which meshes with a drive pinion, the toothed ring is secured to a cylindrical support arranged concentrically to and with a clearance from the drum, and mutually spaced circumferential portions of the cylindrical support are respectively secured to the drum and to the toothed ring, the support being elastically flexible whereby the toothed ring is able to move radially of the drum with flexure of the support. The toothed ring is held in mesh with the drive pinion by guide and support elements which are disposed at the same radial distance from the drive pinion axis but which are angularly spaced about the axis and bear on an inner peripheral surface of the toothed ring.

Abstract: Apparatus for examining objects includes a group of X-ray sources, which are activated group-wise by a generator. A group of sub-images are separately projected onto a photographic film. During a subsequent step, the film is re-imaged with the aid of an optical lens matrix the lenses in the matrix are arranged in a manner similar to the X-ray sources.

Abstract: In third generation computer tomography apparatus, wherein radiation behind the object is measured by means of a large number of detection elements, a detection device comprises a number of detection elements which is larger than necessary for the measurement of the fan-shaped radiation beam, per se, in a direction parallel to the axis of rotation. Means are included for displacing the detection device in the direction of the axis of rotation. Detector element unbalance effects are thus averaged.

Abstract: A method of imaging a three-dimensional object with the aid of coding and decoding using coherent point codes, whereby the object is recorded in two steps, each with a plurality of radiation sources of different orientation on the same recording material.Negatives of the two images are produced, after which the positive of one image is combined with the negative of the other image, the combined images being subsequently multiplied by means of point holograms formed with the aid of a reference wave and a multiplicity of light sources whose co-ordinates correspond to those of the point images of the two source arrays recorded by a pinhole camera, the two multiplied images being superposed in one plane, the coded images being decoded by changing their scale with the aid of two synchronously controlled zoom lenses whereby the coordinates of the point image function of an image of an object layer in the coded images are adapted to the points stored in the two point holograms.

Abstract: A coupling apparatus where two coaxially held coupling halves are connected by a tensioning member provided with a predetermined breaking point. The tensioning member secured at one end to its associated coupling half, is radially and tangentially displaced with respect to the end of the tensioning member secured to the other coupling half. At the overload condition, one coupling half makes a complete rotation, after breaking, with respect to the other coupling half. A rotary escapement is provided as a holding structure so that when one element of the tensioning member swings, it does so out of the path of the other.

Abstract: A method of decoding composite images of three-dimensional objects which are coded by means of a large number of radiation souces of different perspective and which are decoded by means of a point hologram. The point hologram is produced by means of a flat reference beam and by illuminating a shadow mask in the converging beam. The coordinates of the shadow mask correspond to the point image of the source distribution recorded by a hole camera, while the coordinate differences of the holes of the shadow mask have the same value, or a value increased to scale, with respect to the coordinate differences of the point image function of the object plane of the composite image which was nearest to the source distribution during the recording. The decoding of the composite image is effected by shifting between an illumination lens and the point hologram in an incoherent monochromatic converging beam.