Abstract: The invention relates to an internal combustion engine having a turbine-compressor combination connected with the outlet duct for pressure filling by the thrust system; the invention has for its object to improve the shape of the high and steep peak of the exhaust pulse occurring particularly in engines having a high mean effective pressure so that the abrupt gas pulse is smoothed down so that the turbine is capable of operating with higher efficiency, and provides a combustion engine with pressure filling by the thrust system, the exhaust duct of which includes at least one restriction narrowing the passage area.

Abstract: A pollution-free thermodynamic engine system and method for converting thermal potential energy to useful mechanical energy employing an isothermal or quasi-isothermal primary working fluid thermodynamic expansion cycle. A relatively cold primary working fluid is conducted from a low temperature storage tank, through a plurality of engine stages each comprising a heat exchanger and an expansion engine operated on an isothermal of quasi-isothermal expansion cycle, and finally exhausted. A relatively warm secondary fluid is circulated through the engine stages to provide a heat input thereto. The engine stages are connected to the primary working fluid path in parallel to operate on a first isothermal expansion cycle; the engine stages are cascaded to operate on a second serial isothermal expansion cycle.

Abstract: A steam generator is operated by heat generated by combustion of fuel, and supplies steam to an expander. An auxiliary condenser transfers some of the heat remaining in the steam from the expander to air used for burning the fuel.

Abstract: The high density, third dimension geometry solar panels consist of closely placing any type of conventional solar cells in an in depth, oblique attitude to the sun's normal rays.In one panel arrangement, highly polished side reflectors are applied to reflect the sun's rays into the underside groups of solar cells so that a minimum of surface area is required for a higher than normal electrical power yield from the high density cells.The most effective geometric shape for these reflected type of solar panels is the triform, or tri-panel, and modifications of the triform cross-section.Another type of high density solar panel is the V form, or Vee cavity form in which the individual solar cells must have reflective surfaces, for mutual reflection and solar energy concentration.

Abstract: An apparatus and method carried out thereby for preventing formation of sand bars from sand or silt at the outlet of a body of water emptying from inland into another body of water such as a lake or the sea and the like. At least one elongated gutter is provided at the outlet of a body of water from inland to another or receiving body of water such as a lake or the sea. The gutter is disposed above the level of the water in the outlet and may or may not extend through the mouth of the outlet into the receiving body of water. Water is pumped into the gutter to an overflow condition so that it spills over the edges and by gravity falls and creates a splash erosion condition. SUBACKGROUND OF THE INVENTIONThis invention relates generally to apparatus and a method for preventing formation of sand bars from sand or silt at the outlet of a body of water emptying from inland into another body of water such as a lake, or the sea and the like.

Abstract: This invention relates to a floating breakwater comprising an elongated floating body which has a width related to the length of waves to be attenuated. The surface of the breakwater parallel to the water includes a plurality of openings which enclose bodies of water which are preferably of triangular or other non rectangular shape.

Abstract: A riser having a 90.degree. bend at its lower end is installed at an offshore platform by mounting the riser within casing with a horizontal leg from the 90.degree. bend extending through a hole in the wall of the casing and lowering the casing through guide funnels extending inwardly from the framework of the platform. The guides have openings in their side walls facing inwardly through which the 90.degree. bend passes as the casing and riser are lowered. When the 90.degree. bend is a short distance above the ocean bottom, a lug on the casing enters an oblique slot in an orienting funnel. Further lowering of the casing causes orientation of the casing as the lug travels through the oblique slot to a position with the horizontal leg of the bend in the riser extending along the desired azimuth.

Abstract: An apparatus for sealably closing off or separating portions of a mine for safety or other reasons including an inflatable member having a size and shape which corresponds substantially to the cross-sectional size and shape of a mine passage, tunnel or the like to be closed off, a device for attaching the inflatable member to the ceiling of the mine passage, said inflatable member having an inflatable peripheral portion with a closure wall or web portion extending across the space defined by the inflatable portion, a source of compressed gas and means connecting said source to the inflatable portion of the member, said source including a valve with an actuator operable to open the valve so that gas from the gas source can pass into the inflatable member when the inflatable member is suspended from the ceiling of the mine passage, and a slide fastener located in the web portion of the member and movable between a first position in which an opening is formed in the web portion for passage therethrough and a sec

Abstract: An anchor bolt assembly for strengthening mine roofs constructed of a cylindrical anchor member having a bolt threadably received in one end and a temporary thread advancing stop carried on the stem of the bolt which releases or gives only after a predetermined torque is applied to the bolt, relative to the anchor member, to permit the bolt to be finally drawn up against the face of the mine roof after the anchor member into which it is threaded has been solidly secured with an adhesive resin material within a predrilled bore hole in the mine roof.

Abstract: A preformed molded fiberglass reinforced plastic repair sleeve for use on a marine or other submerged concrete pile and a method of applying the same. The sleeve is provided with at least one vertical seam consisting of inside interlocking reentrant bends which together establish an interlocking tongue and groove joint. The joint is maintained effective by self-tapping screws which are in engaged relation with steel closure clips or strips. The sleeve after assembly is centered about the pile undergoing repair and the continuous space which exists between the sleeve and the pile is filled with a suitable grout which, when hardened, encompasses the internal or inside portions of the joint under pressure and prevents unfastening of the seam.

Abstract: Various interrelated ammonia solution, ammonia vapor, and liquid ammonia circuits are provided whereas solar radiation energy is used to boil such solution and produce ammonia vapor which is circulated into low pressure deabsorbing boilers to produce cooling effects suitable for air conditioning and food preservation. The intensity of the solar radiation is used to control alternative modes of operation.

Abstract: A method for refrigerating food. This method, preferably applicable to a food refrigerating apparatus of a corkscrew belt conveyor system, discloses the provision of an air cooler for said apparatus without a limit on where to dispose it but any suitable position in or out of said apparatus. Said air cooler sprays freezing air over the food placed on the moving belt conveyor until the completion of its predetermined distance of trip, the air along said belt conveyor being dehumidified through its gradual cooling in this process thereby enabling the prevention of accommodated constituents from developing frosting of freezing on their surfaces. Said air cooler functions on coolant gas supplied from a container subject to the control of a valve and a thermostat according to temperatures required for the food refrigeration.

Abstract: Disclosed is an improved defrosting system in a compression refrigerator. According to this invention there is provided a defrosting system in which the liquid-phase refrigerant is extracted from upstream of the expansion valve to a defrosting tank which is maintained at an elevated temperature high enough to cause the refrigerant to change from the liquid to vapor phase, and the now vapor-phase refrigerant is supplied to the evaporator where the refrigerant lose its heat in changing from the vapor to liquid phase, and the now liquid-phase refrigerant returns to the defrosting tank. The refrigerant circulates until the evaporator has been completely defrosted.

Abstract: A combined refrigerated display case and walk-in cooler wherein an improved refrigeration system combines a single air circulation means and two distinct refrigeration units, a first refrigeration unit dispersing refrigerated air for a plurality of air curtains travelling across an access opening provided at the front of the display case portion of the combination, a second refrigeration unit dispersing refrigerated air rearwardly to the walk-in cooler portion of the combination. The front access opening provides unimpeded access to the refrigerated space of the display case. Support means are provided between the walk-in cooler portion and display case portion extending between a lower surface of the refrigeration system and the floor for carrying shelves associated with the refrigerated display case portion of the combination.

Abstract: A pulley arrangement is operable by a person located adjacent to a table to lower a food holding container into a refrigerated well in the table and to raise said container with respect to said well sufficiently to render the contents of the container readily accessible to said person.

Abstract: The disclosure herein describes an evaporation tray made in a single piece of molded plastic that includes a series of posts for mounting the compressor above the bottom wall of the tray so that water collected therebeneath may be evaporated by the heat dissipated by the compressor; well means integrally mounted to the bottom wall of the tray serve to collect water formed from melted frost through a drain tube which has its lower extremity securely received in the well means; the drain tube and the well means are arranged to retain water which thus prevents an air return flow through the drain tube inside the refrigerator.

Abstract: A food refrigerating apparatus comprising a spirally laid endless belt conveyor and an air cooler as the main constituents. The food is refrigerated on its belt-loaded vertically gyrating trip within a channel of cooled air as provided by said air cooler functioning on coolant gas passing therethrough, said coolant gas after attainment of its primary object spraying over said belt to add to the air-caused food refrigerating effect. A casing or casings cover the foregoing constituents for shutting them off from the atmosphere except for openings to place on and take out the food to be frozen from said belt conveyor. Characteristically, in this invention, the spiral and vertical extension of said belt conveyor aims at the elongation of the food conveying distance without a big horizontal space, further said air cooler enables dehumidified refrigeration so as to discard conventional frosting or freezing on the accommodated mechanism.

Abstract: A constant velocity universal joint has outer and inner joint members with opposed grooves and balls in opposed pairs of the grooves to transmit torque. A cage between the joint members is provided with a number of radial openings to retain the balls in a plane which bisects the angle between the inner and outer joint members formed when the joint is bent and which is at right angles to the cage. The balls engage surfaces of the radial openings which are parallel with the plane and at least on one side of each ball there is provided a supporting plate which engages the ball by a concave spherical surface or a ball groove and which contacts a surface of the cage opening with a planar face. The balls may also be retained within the openings by means of a supporting ring which may be fixed in the opening or capable of movement therein.

Abstract: A knitting machine has a housing on which is displaceable a support cylinder carrying an array of parallel needle holders displaceable up and down. Two armed levers are pivoted on each of the holders and each have a forked arm formed with an actuating foot and with an anchor foot spaced by a gap from the actuating foot, and another arm that is engaged by a spring carried on the holder that normally tries to bias the lever to move from an operative position into an inoperative position. A slide cam on the housing has lobes or formations which are engageable with the actuating feet of the levers to displace the holders and engageable between the feet of the lever so as not to displace the holders. Furthermore, a tip cam is provided on the housing engageable with the other arm of each of the levers to displace it into the operative position.

Abstract: A continuous tubular one-piece panty hose is formed on a circular knitting machine, wherein the waist opening extends transversely of the direction of knitting and is surrounded by a reinforced elastic section with stitches that resist raveling or breakdown.

Abstract: A doffing jet for use in jet dyeing machines to plait fabrics being dyed therein. The doffing jet is placed adjacent the area where the fabric discharged from the jet enters the kier of the jet dyeing machine and is operated by having a supply of dyestuff supplied to the jet in an oscillating or pulsating fashion with the periods of liquid flow being with a force sufficient to move the cloth toward the outer wall of the kier.

Abstract: A cover lock assembly for maintaining a hatch cover securely mounted to a rigid frame including a guard member which passes over at least a portion of the cover and is insertable in a securement device which is mounted to the rigid frame external to but near one end of the hatch cover. A lock housing is releasably attached to an upper surface of the guard member and is movable to a first position covering the securement device. A bar lock mechanism insertable through the lock housing is partially removable in order to permit movement of the lock housing to a second position exposing the securement device which may then be released.

Abstract: A cable employing device for securing frames to poles and posts; a cable dispensing and recovering casing secureable to a frame which includes releaseable engaging means for one cable end; an improved tensioning system for a cable dispensing casing which ordinarily retains the cable in the casing and returns the cable to the casing after use; a cable retention and return device for use in a cable dispensing container which employs a length of surgical tubing to power the cable retention and return; hinged enclosures for simultaneous enclosure of a cable dispensing system and engagement of a frame support.

Abstract: The present invention relates to a lock cover device particularly intended for use with so-called mortise locks. The device is fabricated of resilient polymeric material which may be readily mounted over the mortise lock, normally without the requirement for completely removing the lock from its mounted position and is characterized by the incorporation of a movable shutter member selectively shiftable between a stable sealing position and a stable keyway exposing position, the assembly including resilient cam and follower means for selectively biasing the shutter to one or the other of said stable positions, the shutter being preferably unstable at any intermediate position.

Abstract: A metal preform is flow formed into a desired structure utilizing segmented dyes. The metal preform is positioned in a chamber comprised of shaping members which define a surface substantially complementary to the desired structure. At least two of the shaping members are spaced from one another and define a groove therebetween. The preform is heated to a temperature suitable for superplastic forming and then compressed such that the preform deforms against the shaping members and into the groove. The at least two spaced shaping members are forced to move into contiguous relationship thereby reducing the size of the groove while forcing further deformation of the preform into the groove.

Abstract: A method and machine for use in hydrostatic extrusion wherein a portion of an elastic-plastic viscous pressure medium is introduced into the rear portion of a container, with the rear end thereof being sealed in a fluid tight fashion. The pressure medium being of such a nature that it has a high viscosity and cannot flow by itself. Subsequently, a billet is charged into the container and then a die is mounted in the container at the forward end thereof. The aforesaid pressure medium is caused to fill around the outer circumferential surface of the billet. In this respect, a high pressure seal is provided for the junctions between the die and the forward end of the container and between the die and the forward end of the billet before the pressure medium flows out of the container in a practically negligible small amount, immediately after which a pressure stem is pushed into the container from the rear end thereof, thus proceeding with the hydrostatic extrusion.

Abstract: A method of controlling the shape of rolled objects in the rolling of plate, sheet, strip and the like through the adjustment of the quantity of a crown made on the rolling roll by heating the inside of the center hole made along the center axis of the rolling roll.

Abstract: A method and apparatus for cooling a rod of a coil form, immediately after the hot-rolling thereof and within which the rod, whose loops are spaced a given pitch from one another, is laid flat upon a chain conveyor, and more particularly upon rails thereof, and transported therealong by means of endless chains, includes the cooling of the rod with cooling fluid or air which is introduced from below the cooling floors through means of nozzle portions formed within the bodies of the cooling floors. The method and apparatus features the arrangement and construction, including the configuration, of the nozzle portions thus formed, the cooling fluid being projected upwardly at an angle within the range of 10.degree.-70.degree. with respect to the plane of the cooling bed, and horizontally at an angle within the range of 10.degree.-150.degree.

Abstract: A press for forming articles such as sphere-like objects and the like from workpieces includes a frame having two fixed mating dies mounted thereon and a crankshaft rotatably mounted on said frame, the crankshaft having crank arms actuating movable dies. A stationary shearing bushing means is disposed between the two fixed dies, and means are provided for feeding an elongated rod to the shearing bushing means. The shearing bushing means has an entry side and an exit side, and a movably mounted shearing knife means mounted on the entry side of the shearing bushing means is operable to cut blanks from the elongated rod. A feeding means is movably mounted on the exit side of the shearing bushing means and is operable to simultaneously receive a cut blank at the exit side of the shearing bushing means while delivering another cut blank to one of the fixed dies.

Abstract: Method and apparatus for the repair of damaged vehicle body structure of the type in which the apparatus is secured to the vehicle body or frame and supports force-applying apparatus and measuring apparatus to permit concurrently the repair of damaged parts and the making of measurements relative to selected datum points. The apparatus comprises a pair of beam members each of which movably supports thereon a pair of clamping means for clamping to the underside of the vehicle body so as to permit these two beam members to be clamped in horizontal parallel spaced relationship to each other transversely to the vehicle's longitudinal axis. A means such as a pair of supporting wheels affixed to each of the transverse beams holds the beams and the attached vehicle in an elevated position to permit the insertion under the transverse beams of a rigid rectangular frame whose length at least equals that of the vehicle body and whose width is less than the length of each transverse beam.

Abstract: A system for simulating the parameters tested by a testing device is described. The testing device is used to verify that a sensor and tone wheel of an anti-skid system are properly functioning and connected. Accordingly, the testing device is used to check the resistance of the sensor, the level and frequency of the output voltage from the sensor, and whether the tone wheel has any missing teeth or is improperly aligned with respect to the sensor. The invention is directed to a system for simulating all these parameters to verify that the testing device is functioning properly.

Abstract: An impact impulse measuring device comprises, in accordance with the invention, an acceleration pick-up which transforms a mechanical shock into electric signals and is connected via an amplification unit to a unit for measuring the peak value of an impact impulse. The impact impulse measuring device also includes a noise rejector comprising a counting decade connected to the output of the unit for measuring the peak value of an impact impulse, a commutator coupled to outputs of the decade, an AND NOT gate, a flip-flop and an AND gate. The outputs of the commutator are connected via the AND NOT gate to an adjusting input of the flip-flop and its output is coupled with the AND gate. Eight levels of noise protection can be set with the help of commutator contacts.

Abstract: A method and apparatus for the continuous automatic measuring of the filterability threshold temperature of a liquid such as a doped diesel oil comprising passing the doped diesel oil through a measuring circuit surrounded by a cooling liquid at a constant flow rate, providing a crystal retaining means beyond the cooled part of said measuring circuit, measuring the pressure differential before and immediately after said crystal retaining means, and providing resistance heating to said measuring circuit when the measured pressure differential exceeds a predetermined value and continuously measuring the temperature of said liquid immediately down stream of said crystal retaining means. The switch of the device is actuated in response to the pressure differential increasing beyond a predetermined level which is caused by a build-up of microcrystals, for turning on the resistance heating circuit and melting the microcrystals.

Abstract: Apparatus for analyzing sample gas consisting of a trace gas contained in a carrier gas. The sample gas is carried through a cylindrical duct; ions from the trace gas are formed, and are subjected to a transverse electric field which concentrates the flux of desired ions into an axial stream located away from the duct walls. The electric field may be produced by a combination of the duct walls and a central axial needle electrode in the duct, or by conical focussing screens or by cylindrical lens elements. The concentrated flux of ions passes through spaced interface and orifice plates containing a gas curtain between them and then passes into a vacuum chamber containing a mass spectrometer or other detector. The curtain gas, which blocks flow of carrier gas into the vacuum chamber, is cryo pumpable (e.g. CO.sub.2). The vacuum chamber contains surfaces cooled so as to cause deposit of the curtain gas thereon, thereby maintaining a vacuum.

Abstract: A method and apparatus for sensing the presence or absence of yarns using a simple airflow in an open slot formed between parallel plates, the presence upstream of the proper yarn path being sensed. In one form, the pressure is sensed at multiple points and averaged to accommodate yarn oscillation.

Abstract: An electromechanical oscillator having a feedback shifted alternately to two different phases, and two digital function generators to derive viscosity and density signals on a time shared basis.

Abstract: A hand-operable durometer has a connection allowing a limited universal pivoting movement between an outer casing and an inner shell in order to facilitate the manual application of a truly axial thrust to a penetrator tip disposed largely within the shell.

Abstract: A unit type strain gauge having a protective outer casing of a hard material provided with an internal space open at one side and a pressing member housed in the internal space arranged to press a strain gauge element attached to it against an object, in which strain is to be measured, the remainder of said space being filled with soft synthetic rubber arranged to maintain the parts of the gauge in position and to maintain a dust proof and moisture proof structure.

Abstract: The specification discloses an improved method and apparatus for determining the time angle of a diesel engine which, in contrast to the present day method, is one which is fast, accurate, and can be readily used on a production line basis. There is disclosed a method and apparatus which, by the utilization of pulses of fixed angular frequency produced by an encoder, and counted between the moment the pressure in the injector line of the cylinder, whose timing angle you are measuring, reaches a predetermined pressure and the moment the piston in the same cylinder reaches top dead center, a number of pulses representing the timing angle of the engine is obtained, which can easily be converted into a reading of the timing angle.

Abstract: A flexure based transducer structure capable of measuring forces along two mutually perpendicular axes without being adversely affected by large extraneous forces or moments. Forces are applied through one annular collar and are transmitted to a central hub by a pair of flexure elements and a pair of strain-gaged sensing beams, such structure being adapted to measure forces along an axis perpendicular to such beams. The hub connects to the hub of a similar structure oriented at right angles to the first structure for the purpose of measuring forces about a second axis. A second annular collar serves as the connection to the force reacting structure.

Abstract: A tuned quick connect and disconnect coupling arrangement includes a tubular adapter removably secured to the output shaft of an engine and has an external spline formed on its periphery. A tuned resilient coupling assembly is secured to the dynamometer input shaft and has an internal spline adapted for meshing engagement with the external spline of the adapter for drivingly coupling the shaft to one another for checking the power output of the engine and is disengageable therefrom for uncoupling the shafts from each other. The coupling assembly includes an annular ring containing the internal spline, an elongate torque tube having a pair of radially outwardly extending flanges secured thereto at its opposite ends with one of the flanges resiliently connected to the annular ring, and a hub having a radially outwardly extending flange formed thereon resiliently connected to the other flange of the torque tube.

Abstract: The invention disclosed herein relates to a tightening system including a wrench for applying torque to a fastener system. Associated with the wrench is a control system including measuring means for developing a first signal representative of the torque applied to the fastener. A second signal representative of a constant incremental time is introduced along with the torque signal into gradient calculating means which develops a signal representative of the slope of a torque-time curve which can be plotted for the particular fastener system being tightened. When the gradient signal falls to a predetermined percentage of the maximum previously stored gradient signal, at the yield point of the fastener system or some similarly significant point on the torque-time curve, a control signal is generated stopping the tightening of the fastener.

Abstract: An apparatus for accurately positioning a tire in a tire uniformity machine. The apparatus includes two members axially movable relative to each other and adapted to mate to form an annular channel for the mounting of a tire, radially movable pawls mounted in one of the members, and a plunger in the other member operative to cam the pawls into engagement with the two members when brought together to lock the members together and prevent their separation during operation of the machine.

Abstract: A storm mapping system detects electrical activity caused by weather phenomena such as lightning strokes and the like and displays information related to the electrical activity as indicative of storm location with reference to an origin which is taken as the observer's location. A cathode ray tube (or other display means) provides a display and locations thereon are illuminated in response to the electrical activity. The azimuth of the display is indicative of the azimuth of the electrical activity. The distance from the reference location to any illuminated location is a function of the signal strength. Although signal strength is not a precise indicator of distance, it is a useful data item in that the more severe storms generate the maximum signal strengths. In contrast to the prior art systems, the storm mapping system of this invention illuminates a location whose distance from the origin is inversely related to signal strength.

Abstract: Apparatus for measurement of the velocity of a helicopter with reference to the air comprises two measurement systems that are substantially identical, associated with a double indicator. The measurements are effected with reference to the longitudinal axis and the transverse axis of the helicopter. Each measurement system comprises a position detector for detecting the position of the cyclic rotor pitch command member along one axis, and a detector of the acceleration component along the same axis, with a substantially identical measurement system associated with the other axis. Computing means effect integration of the algebraic sum of the measured values, and pass signals to the double indicator which indicates velocity of the helicopter along the axes. The acceleration detectors include pendular levels, and all detectors incorporate measurement potentiometers. The apparatus is especially useful in the measurement of the air speed of a helicopter close to hovering conditions.

Abstract: The meter is provided with a housing defining a metering chamber and with a metering member rotatably supported in the chamber. A first rotary element is drivingly connected to the metering member to be rotatable about a rotational axis. The meter is also provided with an indicator mechanism supported on the housing and provided with a second rotary element rotatable about the rotational axis of the first element and separated therefrom by a wall of substantially non-magnetizable material. Each rotary element is provided with two permanent magnets disposed symmetrically with respect to the rotational axis and having their respective axes of magnetization extending parallel to the rotational axis but being oppositely directed. Each permanent magnet comprises a pair of similarly poled component permanent magnets having respective planar surfaces abutting against one another in a plane extending substantially parallel to the rotational axis of the rotary elements.

Abstract: A device for the measurement of temperature within an apparatus, for example, a heat exchanger, is disclosed. The temperature measuring device includes a conduit, one end of which extends from the apparatus. The other end is affixed within said apparatus at a point where the temperature is to be measured. Temperature sensitive means, for example, a sheathed thermocouple adapted to permit insertion from outside the apparatus, is positioned within the conduit. The thermocouple has one end positioned adjacent the measuring point.

Abstract: A method and apparatus for detecting a temperature variation above or below a predetermined value by providing in the area where the temperature variation is to be detected an electrical circuit comprising at least two parallel conductors. The conductors are insulated from each other by a dielectric material and have positioned between them a quantity of a magnetically soft ferromagnetic material having a Curie point approximately equivalent to the predetermined temperature. By transmitting a pulse along said circuit and measuring the time interval before a reflection of the said pulse is detected, the location of a temperature variation can be detected.

Abstract: A device for measuring accelerations, particularly components of accelerations due to gravity comprises a stator having first and second spaced apart electrodes. A deflecting part is suspended between the first and second electrodes and it is displaceable under the influence of gravity in a direction toward one or the other electrodes and in so doing produces an electric signal which is proportional to the displacement amount. The signal is connected to means for indicating the magnitude of displacement as a measure of the acceleration acting upon the device.

Abstract: An altimeter has a pointer which rotates clockwise once round a dial for each thousand unit (feet or meters) increase in altitude, the zero of the dial being in the nine o'clock position.Two digital displays are situated one above and one below the horizontal through the dial zero. When the pointer lies in the upper segment of the dial a reading is shown on the upper display and when the pointer lies in the lower segment of the dial a reading is shown on the lower display. When the pointer is in the region of the zero position (for example within 100 feet of the zero position) a reading is shown on both displays. The upper display then reads thousands corresponding to a pointer position above zero and the lower display reads thousands corresponding to a pointer position below zero (whether the pointer is above or below zero).