Abstract: An overhead projector includes a projection head which contains a pivoting mirror and a pivoting projection lens interconnected by a linkage. Rotation of the mirror causes rotation and translation of the projection lens and automatically corrects for Scheimpflug distortion and loss of overall focus of the projected image.

Abstract: A stretched surface recording disk includes an annular substrate to which are adhesively attached magnetic recording films covering each major surface of the substrate. The substrate has annular ridges adjacent its inner and outer diameters which support the film above and parallel to each major surface and film attachment surfaces adjacent the ridges which are radiused an amount sufficient to place the adhesive in compression, preferably about 0.030 inches (0.80 mm).

Abstract: A recording disc is provided by a disc-shaped, formed-sheet-metal support across which a flexible recording sheet is stretched. The formed-sheet-metal support has a central spindle opening which can be precisely centered by simultaneously punching the spindle opening and the circular periphery, thus permitting high-speed rotation of the recording disc in use.

Abstract: A reactor for use in chemical or physical vapor transport film or crystal growth experiments includes a composite reaction tube which is comprised of an open stainless steel tube which is fused to a closed glass tube. The stainless steel portion of the reaction tube supplies mechanical strength and rigidity for sealing purposes while the glass portion of the composite tube permits visual observation of crystal growth within the composite tube.

Abstract: An electrophotographic copying apparatus includes a copying cycle which always alternates development between two image areas to equalize wear along the length of its photosensitive belt and which eliminates a cleaning cycle after the final copy of a copying cycle to reduce belt revolutions. Also included is a combined charger/precleaner to reduce size and a light image mask to prevent unnecessary toning of the belt.

Abstract: A conductive, carbon-filled acetal resin capstan within a belt driven tape cartridge is rotatably supported by a pin and includes a cylindrical outer surface for engaging a drive belt. The capstan is electrically conductive to dissipate static electrical charges and includes a polytetrafluoroethylene-filled acetal resin sleeve interposed between the pin and the capstan to increase the wear resistance of the capstan where it frictionally engages the cartridge.

Abstract: A grounding clip which is provided to secure the end of a photoconductor film to a reel. The film includes a conductive layer covered by a photoconductive layer and the grounding clip is provided with barbs having sharp edges to scrape through the photoconductive layer during assembly of the clip to the reel and electrically contact the conductive layer. Assembly of the reel to a drive shaft provides an electrical connection through the grounding clip between the conductive layer of the photoconductive film and the drive shaft to ground the conductive layer of the film.

Abstract: Three or more ferromagnetic elements are symmetrically arranged about the face of a permanent-magnet rotor of a turntable motor. Those elements extend to a plane perpendicular to the axis of a rotor. When a magnetic recording disc which has a rigid, planar ferromagnetic surface is moved toward that plane, magnetic attraction secures the disc to the turntable. Preferably the turntable includes a spindle which fits into a central opening in the disc to center the disc on the turntable.

Abstract: A data cartridge includes snap fasteners which extend between parallel walls of the cartridge and which are bifurcated to produce two parallel spring arms which may be compressed for insertion into a hole provided in one of the walls. The spring arms include enlarged heads, which are adapted to pass through the wall adjacent the hole when the spring arms are compressed, and reduced necks which allow expansion of the spring arms and gripping of the wall by the enlarged heads.

Abstract: A support for a stretched recording film and method of attaching the film to the support. The support includes a flat disk-shaped base, an annular upstanding rim which terminates in a reference surface, an annular radially extending bonding lip which includes a bonding surface inclined with respect to the plane of the base, and a groove separating the reference surface and the bonding surface. The method of attaching the film to the support includes deflecting the center of the base to decrease the diameter of the bonding surface, bonding the film to the bonding surface, and ceasing to deflect the base so that the diameter of the bonding surface increases to induce tension in the film. A second protective layer of film may be simultaneously stretched over and bonded to the first layer of film.

Abstract: A receptacle and a cover open like a clam shell to a small angle for access by transducing heads to a magnetic recording disc which is rigid at least at its hub. When closed, the rigid hub is forced into a seat at a drive-access opening in the receptacle, and this seating plus peripheral contact between the cover and the receptacle provide an essentially dust-proof chamber for the recording disc.

Abstract: Videocassette tape spool including a wear button piece which is formed as a separate, small piece and which projects beyond one of the flanges of the tape spool. The wear button piece is molded of a highly abrasion-resistant polymer and is mounted to the hub of the spool by means of a cylindrical stud projecting from the hub and a hexagonal blind bore formed within the wear button piece which accepts the stud in an interference fit.

Abstract: A method of forming a magnetic disk and jacket assembly and the jacket formed thereby. The jacket is formed from a precut sheet of material which is scored or perforated at the midpoint of its length to define a top panel and a bottom panel and around the edges of the bottom panel to define three flaps. The flaps are folded over and adhesively attached to the bottom panel to form a spacer surrounding an adhesive-free circular interior area and defining a central cylindrical cavity. After insertion of a magnetic disk into the cavity, the top panel is folded over and adhesively attached to the spacer. The three edges connecting the spacer and the bottom panel are trimmed to size to complete the assembly.

Abstract: A dual-magnification rear screen projector having a fixed projection lens and two auxiliary lenses which may be positioned before and after the projection lens in the light path to change the magnification of the system. The system is parfocal in that none of the lenses need be repositioned axially along the light path to focus the system at either magnification.

Abstract: A method is described for forming a novel bowed shim for a cassette which includes impacting one surface of a sheet of polymeric material with particles until layer-like portions adjacent its surfaces are differentially expanded and the material is bowed, and then cutting the shim from the material.

Abstract: A shield connector is provided for use with a telephone cable having a central core of individual conductors, a metallic sheath surrounding the central core, and a polymeric sheath encapsulating the shield which offers high initial contact force, a long travel in spring action, and resistance to high amperage currents. The connector includes an inner shoe inserted between the shield and the core conductors, an outer shoe overlying the cable sheath and clampingly engaged with the inner shoe by means of a threaded stud interconnecting the inner and outer shoes through a slit provided in the shield and the sheath, and a tang extending from one of the inner or outer shoes to contact the other of the inner or outer shoes exteriorly of the shield and the sheath.

Abstract: A protective cartridge and drive mechanism for use with a stretched surface recording (SSR) disk. The cartridge encloses the disk and includes a rotary locking mechanism which forces the disk into sealing engagement with the cartridge and an erasure preventative control lever which may be manually operated from outside the cartridge. The drive mechanism includes apparatus which releases the cartridge locking mechanism, a sensor which detects the position of the cartridge control lever and operates to prevent the erasure of material recorded on the disk, and two magnetic transducer heads diametrically spaced with respect to the disk which allow random access to recorded information and switching between information recorded at two locations on the disk without the introduction of interference or receiver screen blanking during switching.

Abstract: A tape cartridge of the type including walls defining an enclosure in which a magnetic tape is directed along a tape guidance path adjacent an edge of the cartridge for access by a magnetic transducer further includes at least three pins bearing against one or both major surfaces of the tape in a direction perpendicular to the plane of the tape, an enlarged shoulder extending from each of the pins toward the tape to bear upon an edge of the tape and provide a containment force parallel to the plane of the tape and in a direction transverse to the direction of tape motion. The shoulders of the pins are arranged alternately along the tape path so that the shoulders of successive pins bear against opposite edges of the tape, and the planes containing the shoulders are spaced a distance equal to or less than the width of the tape to ensure contact between all of the shoulders and the tape edges and positive confinement of the tape in the direction transverse to tape motion.

Abstract: An electrical contact to be inserted into a plated hole through a circuit board includes a mounting portion formed from a thin spline having outer edges and a central slit defining inner edges adjacent the slit which are offset with respect to the outer edges in a direction transverse to the plane of the spline to define outwardly radiused blades which increase the thickness of the spline and provide curved contact surfaces between the ends of the spline and the inner and outer edges of the blades.

Abstract: A hand held dispenser for liner wound adhesive tape having walls that define a first cavity for storing a supply roll of liner wound tape, a second cavity with an inner wall surface which causes liner pushed into the second cavity to wind into a coil, an opening through which liner may be withdrawn from the dispenser, and a other means for connecting the first cavity and the opening adapted to guide the tape being withdrawn through the opening, and for connecting the cavities to guide the liner from the first cavity into the second cavity, and for separating the liner from the tape being withdrawn so that tape being withdrawn will propel the liner along the path means and into a coil in the second cavity.