Abstract: A process for stabilizing precursor fibers for the production of carbon fibers is disclosed. The process comprises the following steps: continuously introducing, passing and removing said precursor fibers into, through and from a process chamber; establishing a predetermined process gas atmosphere different in composition from ambient air in said at least one process chamber, said process gas atmosphere containing at least one of a reactive component and a catalyst having a predetermined partial pressure; while said precursor fibers are in said process chamber, heating the precursor fibers to at least a first temperature and maintaining said first temperature for a predetermined period of time.

Abstract: A description is given of continuous fibers based on cellulose and/or cellulose derivatives, more particularly for producing flame-retardant textiles or carbon fibers. The cellulose and/or the cellulose derivatives are in a dehydrated form in the continuous fibers. The oxygen content is 29 to 39 wt %, the limiting oxygen index LOI is 25 to 40 (according to DIN EN ISO 6941; 2004-05) and the density is 1.3 to 1.45 g/cm3 (according to DIN 65569-1; 1992-10). The continuous fibers may be produced advantageously by impregnating the starting fibers with a solution, more particularly an aqueous solution, of a specific salt which under thermal conditions releases a dehydrating acid which brings about the dehydration of cellulose and/or of cellulose derivatives in a subsequent thermal stage. The continuous fibers of the invention can be used in particular to produce advantageous carbon fibers.

Abstract: The invention relates to a method and to a device for stabilizing precursor fibers for the production of carbon fibers. In the method, precursor fibers are first heated to a first temperature and held at the temperature for a predefined duration. Subsequently, the precursor fibers are heated to at least one second temperature, which is higher than the first temperature, and held at said temperature for a predefined duration. During each heating and between the heating steps, the precursor fibers are in a gas atmosphere having a negative pressure in the range between 12 mbar and 300 mbar and having an oxygen partial pressure of 2.5 to 63 mbar. The device has at least one evacuable, elongate vacuum chamber for feeding the precursor fibers through, at least two lock units and at least one heating unit.

Abstract: The invention relates to a method and to a device for stabilizing precursor fibers for the production of carbon fibers. In the method, precursor fibers are first heated to a first temperature and held at the temperature for a predefined duration. Subsequently, the precursor fibers are heated to at least one second temperature, which is higher than the first temperature, and held at said temperature for a predefined duration. During each heating and between the heating steps, the precursor fibers are in a gas atmosphere having a negative pressure in the range between 12 mbar and 300 mbar and having an oxygen partial pressure of 2.5 to 63 mbar. The device has at least one evacuable, elongate vacuum chamber for feeding the precursor fibers through, at least two lock units and at least one heating unit.

Abstract: When a trigger lever is depressed, both a focus adjuster ring and a control disk commence to rotate in unison, driven by a spring mechanism. Position-sensing switches receive signals indicating which subject-distance setting the focus adjuster ring should be arrested at, and furthermore are opened and closed by the control disk during movement of the latter. When the focus adjuster ring reaches the required subject distance setting, it is arrested and kept arrested, thereby completing an automatic focussing operation, but the control disk continues to turn on to its end position, at which it causes the shutter mechanism of the camera to open and furthermore the exposure-timing circuit of the camera to initiation a scene-light-dependent exposure-timing operation.

Abstract: When a trigger lever is depressed, both a focus adjuster ring and a control disk commence to rotate in unison, driven by a spring mechanism. Position-sensing switches receive signals indicating which subject-distance setting the focus adjuster ring should be arrested at, and furthermore are opened and closed by the control disk during movement of the latter. When the focus adjuster ring reaches the required subject distance setting, it is arrested and kept arrested, thereby completing an automatic focussing operation, but the control disk continues to turn on to its end position, at which it causes the shutter mechanism of the camera to open and furthermore the exposure-timing circuit of the camera to initiation a scene-light-dependent exposure-timing operation.

Abstract: The bellows type folding camera includes two pairs of collapsable struts symmetrically hinged inside the bellows between the camera housing and the displaceable objective support; the upper and lower struts are interconnected by transverse straps and only one of the struts is operated by an actuation handle whereby the movement of this one strut is transmitted to the remaining struts by a coupler and crank linkage and by the transverse straps.

Abstract: A first photodetector arrangement comprises three adjoining photodetectors, and a second comprises six. First and second optics, and the two photodetector arrangements, are located immovable on the camera, and the optics project onto the first arrangement an image of a subject which is to form the basis of a subject-distance measurement, without shift between image and photodetectors of the first arrangement so long as the subject-distance is within one of the ranges the system is to furnish; whereas the image projected onto the second photodetector arrangement shifts relative thereto in dependence upon the distance to the subject. The six photodetectors of the second arrangement are subdivided, for signal-processing purposes, into four successive groups, respectively comprised of the first, second and third photodetector, the second, third and fourth, the third, fourth and fifth, etc.

Abstract: A focussing system emits an infrared light beam towards the subject, the reflected beam passing through an infrared filter and being projected by a spot optics as a small spot onto a pair of photosensitive elements. The spot optics shifts in a plane normal to the camera's optical axis in dependence upon rotation of the camera's focussing ring, to vary the distribution of the reflected beam onto the two elements, the distribution being equal between them when the state of focus is correct. A circuit derives, from the output signals of the two photosensitive elements, a state-of-focus signal used to automatically focus or else to indicate to the user the direction in which he should manually adjust focus. When focussing is finished, the photosensitive elements are disconnected from the focussing circuitry and connected to the camera's exposure-control circuitry, to thereby serve a dual function. The infrared filter moves out of the light path of the photosensitive elements.

Abstract: A photographic apparatus which can accept cassettes having markers denoting different film speeds. When a cassette having a particular marker is inserted into the housing, it displaces a spring-biased scanning lever which thereby allows or prevents a filter to move into register with the picture taking lens. Complete closing of the door for the film chamber results in engagement of the scanning lever with a displacing lever which moves the scanning lever slightly away from the marker so that the scanning lever cannot interfere with proper orientation of the cassette in the housing. Alternatively, the scanning lever can be disengaged from the marker by a film transporting or shutter actuating member which engages the scanning lever with another lever to thereby hold the scanning lever out of contact with the marker.

Abstract: A camera has a pair of nip rollers which are rotated by a toothed belt via gears. Function-controlling elements mounted on the camera are operated when the belt moves.

Abstract: A photographic camera, particularly an instant-picture camera, has a set of transporting rollers between which a film is advanced. An actuating arrangement is mounted for movement from a starting position to an operating position in order to rotate the transporting rollers, and back to the starting position. An energy storing arrangement is connected to the actuating arrangement and stores energy during movement of the same to the starting position, this energy being dissipated during movement of the actuating arrangement to the operating position in order to thereby aid in such movement.

Abstract: An arrangement of a photographic camera, preferably an instant-picture print camera having two light reflecting mirrors between the objective and a rectangular film strip. According to this invention, the angular position between the mirrors is adjusted such that at least one section of the path of travel of light rays between the objective and the large mirror assigned to the film strip forms an oblique angle with an edge of the film strip.

Abstract: A photographic camera comprises two deviating mirrors arranged within the camera housing between the objective and the film strip in such a manner that the optical axis of the light rays between the objective and the assigned first mirror lies on a different plane than the optical axis of the rays between the second mirror and the film strip.

Abstract: A self developing type photographic apparatus wherein one of the spread rollers is driven by one or two toothed racks forming part of or constituting a manually reciprocable handle. One of the racks further rotates a gear which programs the movements of an expelling device for exposed film units, the movements of a device which controls the width of the gap between the spread rollers and the cocking of the shutter.

Abstract: A photographic camera has a film transporting mechanism which requires different amounts of energy during different phases of each film-transporting cycle. A gear drive is provided which furnishes to the mechanism differing energy amounts while itself receiving a substantially constant energy input.

Abstract: A collapsible camera has a lens mount which is pivoted on the camera body and can move between an open and a shut position. An arcuate drive segment is composed of at least two segment parts, both of which pivot on the same pivot axis as the lens mount. These parts can move relative to one another and to the body and lens mount when the latter is opened and closed. The periphery of each part has serrations which engage with the teeth of a pinion that constitutes the input member of a film transporting mechanism so that the pinion is rotated in response to the pivoting movement of the lens mount.

Abstract: An improved pressure roller in a photographic apparatus of the self-developing type is disclosed. The roller has a rigid core provided with two axially spaced circumferential grooves which are filled with resiliently compressible material. The core is jacketed with a resilient sheath which covers its circumferential surface, including the grooves and the material therein.

Abstract: The camera has a housing and a lens. A film transport mechanism is arranged in the housing. An operating element includes a member which is displaceable by a user in longitudinal direction of the optical axis of the lens and which, during at least part of such displacement, actuates the film transport mechanism. The operating element may include two of these members; if so, they are located at opposite lateral sides of the lens and are coupled so as to move in unison.

Abstract: A film transporting mechanism for use in still cameras wherein a lever or wheel constitutes the input member of a planetary transmission. The sun gear or planet carrier of the transmission is held against rotation by a film scanning device during a first stage of rotation of the input member from its starting position to a fixed end position and while the input member rotates a spur gear or an internal gear by way of one or more planet pinions whereby the spur gear or internal gear rotates the takeup reel in a direction to collect the film. When the transport of film by the length of a frame is completed, the scanning device releases the sun gear or the planet carrier and arrests the spur gear or internal gear to thus terminate the transport of film while the input member continues to rotate toward its fixed end position and drives the sun gear or planet carrier.