Abstract: A tool for use in establishing a precise level line or plumb line or line for alignment uses a visible laser diode for projecting the line. The tool is relatively small and compact, drives the laser diode using batteries contained in the tool, and includes tilt compensation for use on surfaces which are not level, up to about 5.degree. off level, for still delivering a truly plumb or truly horizontal beam. A manual selector device is provided for shifting the beam from a vertical orientation to a horizontal orientation when desired. Specific forms of tilt compensation apparatus are disclosed.

Abstract: A portable computer is constructed to utilize bottom add-on expansion modules, battery tray compartment plug-in modules and mass storage plug-in drawer modules. The modules permit the operating capabilities of the portable computer to be readily altered as desired or as needed at a given location or for a particular job function and do not require redesign or alteration of the internal components of the portable computer as modules are added or changed. Each module construction includes direct plug-in connectors which permit the add-on module to be directly connected to the computer bus without any cabling between the computer and the added module. The construction of the add-on modules permits the computer to be operated as a stand alone computer without any add-on modules and permits the computer to be operated as a portable computer powered by a battery.

Abstract: A control system particularly for a modulated laser diode such as for use in laser printers, laser communication systems, optical data storage and other uses employs bipolar integrated circuitry on a single chip with very few external components. The circuit is simple and of low cost and dependable construction and compensates for relatively slow changes in the output characteristics of the laser diode as caused by aging, temperature changes or other varying conditions. The drift compensation is accomplished through current differencing and combining a current difference signal with a modulation input signal to drive the laser diode.

Abstract: A high powered beam dump apparatus and method for absorbing the power of a high power laser, while the beam is shuttered off from contact with a workpiece, comprises two principal features. A reflecting cone reflects and spreads the high power laser beam outwardly from the axis of a high power laser beam when the beam dump is positioned with the axis of the cone coaxial with the axis of the incoming laser beam. An absorber extends circumferentially about the reflecting cone surface and absorbs the power of the beam as reflected from the reflecting cone surface. The materials and surface finishes of the conical reflecting surface and the absorber and the angle of the reflecting cone are related to the wavelength of the high power laser beam with which the beam dump is associated so as to absorb essentially all of the power of the laser beam when the beam dump is moved into the beam shuttered off position.

Abstract: Method and apparatus are disclosed for teaching with the use of an electronic processor and associated display, preferably in conjunction with a conventional textbook, the method comprising the steps of selecting verbal data providing a description of a selected concept and animation data providing a visual, non-verbal illustration of the same concept, storing both the verbal and animation data in the processor and operating the processor for displaying the verbal and animation data to a student separately and in a selected and predetermined sequence for impressing both the verbal and animation data upon the student. Corresponding apparatus according to the invention comprises an electronic device with a processor component, a display component and necessary control components for carrying out the steps of the invention as set forth above.

Abstract: A tool for use in establishing a precise level line or plumb line or line for alignment uses a visible laser diode for projecting the line. The tool is relatively small and compact, drives the laser diode using batteries contained in the tool, and includes tilt compensation for use on surfaces which are not level, up to about 5.degree. off level, for still delivering a truly plumb or truly horizontal beam. A manual selector device is provided for shifting the beam from a vertical orientation to a horizontal orientation when desired. Specific forms of tilt compensation apparatus are disclosed.

Abstract: An alignment apparatus for aligning a main, high power laser beam with a workpiece by the use of a low power laser beam while the main, high power laser beam is shuttered off from contact with the workpiece includes a periscope for displacing the low power beam laterally to be coaxial with the axis of the first beam during the time that the high power beam is shuttered off from the workpiece. The alignment apparatus includes adjustment mechanism for adjusting the angular position of the low power laser to make the axis of the low power laser beam exactly parallel to the axis of the high power laser beam for the particular periscope being used.

Abstract: An optical bar code reader using a light source which can be switched on quickly and includes provision for activating the light source and related devices only when data is actually being gathered, rather than wasting a large amount of beam on time and energy as in prior software based scanners.

Abstract: A co-axial laser tube structure of the kind used in a flowing gas laser has an inner axially extending tube for confining the flowing gas in a discharge region, a single pin cathode mounted adjacent the hot end of the inner tube, a single pin anode mounted intermediate the cool end and the hot end of the inner tube, a gas entrance orifice for permitting gas to flow from the exterior tube into the interior of the tube at the location of the anode electrode means, and an outer tube which is separate from and which extends co-axially with the inner tube. The outer tube is made of plastic and conducts flowing gas along the outside of the inner tube from the cool end to the gas entrance orifice. The co-axial laser tube structure includes tube installation and mounting means effective to permit installation and/or replacement of the inner and outer tubes without the need for subsequent adjustment or bore registration of the tubes.

Abstract: A flowing gas laser, of the kind in which gas flows continuously through the lasing region and is circulated through the heat exchanger for cooling before being returned to the lasing region, comprises a resonator module and a blower module. The optical components of the laser are mounted on an outer surface of the resonator module, and the resonator module has an interior structure for conducting the circulating gas to the lasing region. The blower module has heat exchange structure for cooling the circulating gas and has a blower for pumping the circulating gas. The blower module is physically separated from the resonator module to prevent the heat and vibration of the blower module from distorting or otherwise affecting the structure or the performance of the optical components. Ducting the interconnects the resonator module and the blower module for circulating the gas between these modules.

Abstract: An alarm-generating writing device is disclosed, the constitution of which is such that a push bottom switch is provided on the body of the writing device (pen or pencil), the push button switch being able to close the circuit in order to activate an alarm. When the user of the writing device releases the push button switch due to exhaustion or falling asleep, the springing push button switch closes the inner circuit of the writing device in order to activate the alarm, whereby awakening the user from the sleeping state.

Abstract: Methods and apparatus for exchanging frames between bridges distribute load sharing in a communications network. The communications network is of the kind in which bridges, and related stations and local LANS, e.g. Ethernet LANs and 802 LANs, can be linked by paths in a plurality of sub-networks and wherein the bridges are linked to support a Spanning Tree Protocol (STP) which elects one bridge as a root and then with respect to said root, computes and utilizes one and only one loop-free set of primary paths between all bridges. Remaining paths, i.e. paths other than said STP primary paths, between the bridges are examined as possible sub-network paths for a Distributed Load Sharing (DLS) configuration in which frames exchanged between certain stations can utilize more than the STP one set of primary paths. Certain ones of the remaining paths are selected as DLS paths under certain conditions and frame are routed over a selected DLS path only when those frames meet certain criteria.

Abstract: A self-propelled table for carrying and/or lifting/lowering objects for invalid people having a hollow plastic upper enclosure which is padded at the edges and upon the surface of which contains anti-slip recesses and a joystring assembly. The lower portion of this assemblage is attached to a vertically mounted, telescoping tubular assembly which may be either fixed or supplemented with a motor-power assembly with which to adjust the height-away-from-the-floor of the uppermost serving surface. The bottom of the tubular assembly is attached to the upper portion of a hollow plastic lower enclosure which contains wheels, motors, batteries, and electronic circuits to translate the electronic signals from the joystring into meaningful wheel motions. Pulling the free end of the joystring causes the invention to propell itself and it's load in the same direction that the joystring was pulled; thereby providing handicapped people with the ability to perform simple tasks unassisted.

Abstract: A controller for a bridge interconnecting local area networks operates in two modes. In a first mode the controller receives and transmits station data frames with previously appended frame check sums. In a second mode the controller responds to requests for information from stations by generating data frames from an associated memory. The controller computes and appends frame check sums and then transmits the frames and check sums to the requesting station. The controller is constructed and is effective to operate in a way which insures that all station data frames transmitted from stations to the bridge are received by the bridge without interruption or loss during all periods of operation. The controller receives all such frames at all times, including the time intervals during which circuitry in the controller must be off line and reprogrammed for changing operation between the first and second modes.

Abstract: A compact counter-type bar code scanner produces a "five-apparent-source" scan geometry within an optimum scan volume above the deck of the bar code reader, with a total scanner housing height of less than 13 centimeters, and preferably about 11.5 centimeters. The optics are maximized to achieve approximately the same bar code reading efficiency and reliability as in previous much deeper bar code scanners producing similar scan geometry by reflecting the scanned beam off three surfaces, the last of which is horizontal.

Abstract: A system for control of a bar code scanner threshold with deliberate decay includes monitoring a selected scan signal characteristic of characteristics and electronically determining whether sets of signal characteristics represent a bar code or extraneous noise, and, if noise is indicated, raising the black/white threshold until noise is no longer detected. The monitored characteristics can include frequency of perceived black/white transition. In a preferred embodiment, the raw scan signal is processed through two circuits, a first circuit wherein a threshold is generated based on the signal and a selected threshold criterion, and a second circuit wherein the threshold generated in the first circuit is applied to the signal to produce a bar signal output, which output is then monitored by a noise recognition device. If noise is perceived by the noise recognition device, a threshold offset signal is generated. The threshold generated in the first circuit is raised by adding to it the threshold offset signal.

Abstract: A carpet and pad installation avoids the need for stretching and tackless strips by utilizing a pad with pressure-sensitive adhesive on one surface. The pad is first laid on the floor surface and trimmed as required, with either the adhesive surface down to adhere to the floor, or with the adhesive surface up and another adhesive applied to the floor prior to laying the pad. A removable release film may cover the pressure-sensitive adhesive on the pad, so that with the adhesive side up the carpet may be unrolled over the release film and then cut and seamed as required. The seamed carpet is folded back and the release film is removed from the exposed area of the carpet cushion, then the carpet is pressed down onto the exposed area of adhesive. Then another portion of the carpet is folded back, the release film is removed from that area, and that portion of the carpet is pressed onto the exposed pressure-sensitive adhesive of the carpet cushion.

Abstract: A method and apparatus for measuring gas flow volume in a system (of the kind in which the amount of gas flowing in a duct can vary in response to the variation of area of a variable area orifice in a duct and/or in response to changes in the total pressure of the gas upstream of the orifice) references the total pressure upstream of the orifice to the static pressure downstream of the orifice to produce a first signal representative of the differential pressure between the total pressure upstream of the orifice and the static pressure downstream of the orifice. The method and apparatus produce a second signal corresponding to the area of the opening in the orifice. The first and second signals are supplied to a gas flow volume database which is correlated to the sensors and to the orifice in the duct. The gas flow volume occurring in the duct at the first and second signals is read out from the database.

Abstract: A floating mirror mount for a mirror of a laser comprises a mirror having a front surface and a back surface. A keeper encircles the mirror and has a peripheral flange which engages the front surface of the mirror when the mirror mount is not installed in a laser. A retainer is connected to the keeper and has a spring seating surface. A movable spring plate has a surface engageable with the back surface of the mirror. Springs are engagble with the spring seating surface and with the spring plate for exerting a resiliant biasing force on the mirror which is sufficiently large to force the mirror against the peripheral flange of the keeper when the mirror is not installed in a laser. The spring force is sufficiently small to permit the mirror to be moved out of contact with the peripheral flange and to a different location when the front surface of the mirror is engaged by mirror positioning structure of the laser in the course of installing the mirror mount in a laser.

Abstract: A dye laser is of compact, rigid and simple construction, with a folded resonator cavity contained on a single rigid block of material, such as aluminum. The block has two or three mirror mount locations, at least one of which is a machined surface which receives a mirror directly and rigidly, without provision for adjustment. The other mirror mount location(s) has an adjustable mirror mount, and this may be the mirror mount for the output mirror. A dye jet mounting block has a flat surface which engages against a flat surface on the exterior of the laser block, with fasteners allowing for rotation and translation of the dye jet block on the laser resonator block to provide for both rotational and translational tuning adjustment of the dye jet with respect to the resonator cavity and a pumping beam. The pumping beam preferably is folded by an adjustable pump mirror on its approach to the dye jet.