Abstract: A filter leaf includes a continuous, elongated closure member, a first screen welded around its entire periphery to one side of the member, and a second screen welded around its entire periphery to the other side of the member to define a filtrate collection space between the two screens and the member. Means are provided for removing filtrate from the collection space. The filter leaf is made by clamping the closure member and one of the screens between two plates so the screen covers one side of the member and so the outer portions of the member and screen project outwardly from one of the plates. The outwardly projecting portions of the screen and member are irradiated with a laser beam to melt the screen and member to cause them to fuse together. The periphery of the outwardly projecting portions of the member and screen are moved relative to the laser beam while the member and screen are clamped together to form a continuous weld of the screen to the member around the entire periphery of the screen.

Abstract: A press system that provides rapid advance of one platen on a movable crosshead through the use of programmed hydraulic controls and is specifically adapted for use with sheet molding compound (SMC) presses. Rapid locking or latching of the crosshead and the platen it carries is achieved through the use of hydraulically operated clamping and release cylinders. The lower platen is supported on hydrostatic bearings permitting the platen to move and at the same time parallelism of the mold halves is maintained by swiveling molding power cylinders. Separate push-back cylinders are used to separate the mold through a short load path so that when the mold "breaks away" there is very little springback to minimize any part breakage during mold stripping.The lower platen also includes a mounting arrangement that provides the advantages of a rolling bolster or lower platen with a minimum of mounting structure.

Abstract: A "mode switch" is used for smoothly switching a servovalve controlled device such as an SMC press, in particular, from control under one parameter to control by another. The mode switch provides a very smooth transfer of control from displacement control between two relatively movable parts to force control to provide for controlling the force exerted by actuators acting between the two parts. The mode switch electronically tracks the signals so that when the switching is made the signals are precisely equal to prevent abrupt changes in the control signals. This smooth transfer is achieved even under active control, that is when both control signals are changing in value.

Abstract: A transducer arrangement provides a feedback signal which indicates the position of a first part relative to a base and when a second movable part is positioned adjacent the first part the transducer provides a signal indicating the spacing between the two parts. Specifically the transducer provides for spacing control between the two halves of a mold mounted in a press wherein a crosshead moves a substantial distance and carries one part of the mold (the upper half) relative to the lower mold part. Hydraulic actuators act on the lower part of the mold to provide the molding force when the mold parts are close together. The transducer is mounted in a housing and arranged to provide a signal used for controlling the hydraulic actuators to control the spacing of the two molds parts unitl the mold parts are separated a known amount, after which the hydraulic actuators are controlled by sensing the spacing of one mold half relative to the base of the press.

Abstract: A method and apparatus is provided for toning a latent electrostatic image on an exposed photoconductive surface of an electrophotographic member, using liquid toner comprising toner particles suspended in an electrically insulating liquid dispersant. Plural, generally identical, toner modules are arranged side by side at a first level, each module comprising a toner tray having a development electrode mounted on the upper surface thereof. The development electrode has a planar upper surface. A motor operates an articulated linkage which causes the tray to be elevated to a second level for toning, one of the modules being selected from the others. Antifriction bearing surfaces are mounted on the upper surface of the tray at opposite ends of the development electrode. The antifriction surfaces extend upwardly of the development electrode a short distance slightly above the upper surface thereof to define a gap between the development electrode and the surface to be toned.

Abstract: Documents are encoded with at least one thin, transparent coating, normally invisible, but having a readily detectable physical characteristic such as, electrical conductivity, electrical impedance, electrical capacitance, electroluminescence. Each document consists of a substrate on which is applied (1) at least one of the thin coatings, and (2) conventional printing, preferably intaglio. The thin coating may be applied before or after the printing. The coating includes particles driven into the surface to a substantial depth. The uncoated substrate is free of the detectable physical characteristic. The coating is confined to a limited area of the substrate surface and itself constitutes a code or is laid down in a pattern for identification. A second coating can be applied so that all areas of the surface have the same appearance to mask visual detection of the first coating.

Abstract: A digitizer tablet providing accurate two-dimensional coordinate location of the position of a cursor over the entire surface of the tablet. The position values are derived from sequential pulse signals eminating from a grid matrix within the plane of the tablet and received by a magnetic pickup within the cursor body. The grid matrix is energized with signal pulses and arranged in a predistorted manner to extend the useful area of the tablet to include the edge of the grid matrix. Furthermore, the tablet matrix and the associated drive and calculating electronics are incorporated on a unitary circuit board wherein the electronics are within the tablet area useable for cursor location determination.

Abstract: Oil is preferably recovered from oil shale through the use of a process involving two separate heating steps. During the first of these steps the shale is heated by contact with a hot gas stream while it is agitated for a period and at a temperature which together are such that any significant further heating will cause the vaporization of pyrolysis products of the kerogen within the shale. During the second heating step the shale is further heated by contact with a hot gas stream while being agitated for a period and to a temperature which together are sufficient to produce and volatilize substantially all of the volatiles which can be obtained from or derived from the shale. After the second heating step the vaporized products and the remaining inorganic mineral matrix are separated, and the volatiles are recovered as oil.

Abstract: An arrangement for recording an analog signal onto magnetic tape in which the analog signal modulates a square wave bias field by moving the negative-going transition of the square wave so that the average of the positive portion and negative portion of the square wave, equals the instantaneous value of the analog signal. The period of the total square wave, is maintained constant. The analog signal is compared to a periodic triangular-shaped wave, in a comparator, and the output of the comparator becomes switched in polarity whenever the analog modulating signal is equal in value to the instantaneous value of the triangular wave. The point at which polarity is switched corresponds to an intersection of the analog signal superimposed on the triangular wave. The resultant modulated square wave is applied to a recording head.

Abstract: An apparatus for photochemically curing organic composites used to repair teeth includes a quartz halogen lamp (12) which is activated for a particular length of time by a cycle control circuit (42) which produces a control signal for a preselected time interval. A switching circuit (38) is coupled with the cycle control circuit (42) to interconnect an alternating current source with the quartz halogen lamp (12) at a point in the alternating current cycle when the alternating current crosses a zero voltage level. The control circuit (42) is operably coupled to a time delay circuit (40) which activates the control circuit (42) after a preselected time period after activation of the control circuit (40).

Abstract: In an apparatus of the type including a magnetic transducer head adapted for flying on a fluid bearing in close proximity to a transducing surface and a gimbal apparatus to which the head is mounted for flying so as to provide flexural freedom of rotation of the head around roll and pitch axes parallel to the transducing surface and flexural freedom of translation in the direction of an axis perpendicular to the surface while restraining rotation of the head about the axis perpendicular to the surface and translation of the head in directions parallel to the surface, the gimbal apparatus comprising a thin, resilient, gimbal sheet having an external shape and interior openings defining an outer ring attachable to a gimbal sheet support at substantially opposite points on the outer ring and an inner ring spaced apart from the outer ring and attached to it by a pair of webs intersecting the outer ring at opposite interior edges between the points at which the outer ring is attached to the gimbal sheet support, t

Abstract: An energizing circuit (10) for automatically driving a piezoelectric crystal transducer (Y1) at its resonant frequency includes a resonant circuit (12) of which the transducer (Y1) forms a capacitive element and the secondary winding (80) of a transformer (T2) forms an inductive element. In addition, the piezoelectric crystal itself acts as a series RLC circuit disposed in parallel with the parallel capacitive and inductive elements of the resonant circuit (12). Secondary winding (80) is inductively coupled with a primary winding (74) of the transformer (T2) which forms part of a driving circuit (14). The driving circuit (14) includes a switching circuit (20) connected between a power supply circuit (16) and the resonant circuit (12).

Abstract: A single stepper motor is utilized in a printing device to lift a print head from the surface of recording material upon the initial angular rotation of the stepper motor output drive shaft and to move the recording material within the printing device upon further rotation of said drive shaft. The print head is returned to the surface of the recording material by operating the stepper motor in the reverse direction until the output drive shaft of the stepper motor traverses an angular displacement equal but opposite to the initial angular displacement. A cam surface couples the output drive shaft of the stepper motor to a drive gear and transforms the initial angular displacement of the output drive shaft into linear motion to lift the print head from the surface of the recording material. Further rotation of the stepper motor drive shaft rotates the drive gear to move material within the printing device.

Abstract: A film support element assembly is disclosed, primarily for supporting film in relation to a projection aperture in a motion picture projector having a rolling loop film transport mechanism. In a preferred embodiment the film support element is a so-called "field flattener" and has a cylindrically curved surface over which successive frames in the film are laid by the mechanism. Cleaning means are provided adjacent the film path and the lens element can be displaced to bring a fresh portion of the surface into the film path. At the same time, the cleaning means remove debris from the surface. In one embodiment the lens element is vibrated to discourage adhesion of debris.

Abstract: An original image is reproduced on an electrophotographic member with a series of binary data bits having a statistically valid count corresponding to the relative density of the original image.A sensor senses the density value of individual information forming structure or structures in incremental areas of the original image and converts the density values into a series of binary data bits, one bit per incremental area. An imager receives the binary data bits and forms one binary element on the charged electrophotographic member surface in response to each bit. The elements formed on the member surface correspond in sense to the binary data bits from the sensor and the elements are formed in incremental areas of the member corresponding to the incremental areas of the original image from which their respective binary data bits were produced.

Abstract: A system is disclosed in which signals are presented to a listener with a spatial impression in which the signal which is desired appears to be coming from a source in front of the listener while other signals appear to be coming from audio sources to the right and left of the listener. The same is achieved through a combination of a heterodyne type detector and a combination of high pass and low pass filters receiving the output of the detector. The outputs of the high and low pass filters are separately amplified and each sent to one ear of the listener.

Abstract: An insulating device reduces heat transfer through a barrier--such as a wall, window, door, floor, or ceiling of a building--and into an area adjacent to the device. The insulating device includes at least one flexible sheet supported from an area above the section of the barrier to be insulated and is attached at its free end to the barrier above that section. Accordingly, the flexible sheet is doubled back upon itself and forms an insulating air space. A second flexible sheet can be attached to the support and disposed around the exterior of the first flexible sheet and attached to the barrier above the section to be insulated. Where two flexible sheets are doubled back upon themselves in such a manner, three insulating air spaces are provided. Accordingly, the insulating device impedes conductive heat transfer across the device. At least one flexible sheet includes a material having a low emittance to reduce radiant heat transfer across the device.

Abstract: Apparatus is described for providing controlled corona charging of an electrophotographic member that moves past a corona charging electrode. A corona sensor probe near the charging electrode receives a sample of the corona current flow from the electrode that is proportional to the current flow as it may be modified by extraneous influence, including air pressure, humidity, and corona electrode potential. The probe produces a signal that is adapted to vary the movement rate of the member past the charging electrode, being faster for a sensed increase of corona current and slower for a sensed decrease of corona current. The effective result is an electric charge on the electrophotographic member surface that is uniformly about constant, independent of the variations wrought by most external influences.

Abstract: A tow plate assembly for an aerial cargo parachute delivery system is disclosed. The tow plate assembly includes an extraction clevis member connected between at least one extraction parachute and a cargo load and a drogue jettison clevis member mounted on the extraction clevis and connected to a drogue parachute. Remote operating linkages are provided for mechanically releasing the clevis members to extract the load or, in the case of an aborted mission, to jettison the drogue parachute. Both clevis members are releasably retained on the tow plate by mechanisms constructed to minimize the force required for release, the extraction clevis by a ball locking device and the drogue jettison clevis by a combination of anti-friction bearings and clevis structure to maintain a minimum vertical component of the drag force acting on the drogue clevis locking elements.

Abstract: A filtering apparatus suitable for being cleaned by backwashing includes an outer housing (11) and an inner filter (13) disposed in the outer housing defining an outer annular flow passage (16) and an inner flow passage (17). The outer housing is tapered in relation to the external shape of the filter to provide a substantially uniform liquid velocity through the filter in both forward flow and backflow directions. The filter is made up of a plurality of ring-like segments (38) stacked end to end on which a filter medium (37) is mounted.