Abstract: The grade-leveling tool is a measurement device. The grade-leveling tool forms a vertical barometer. The grade-leveling tool measures the difference between: a) a desired elevation from the ground at a specific location; and, b) the existing elevation of the ground. The grade-leveling tool is used to create a bed of level ground used for supporting a structure. The grade-leveling tool comprises a base structure, a reservoir structure, and a hose structure. The hose structure and the reservoir structure attach to the base structure. A fluidic connection is formed between the reservoir structure and the hose structure. The base structure elevates the reservoir structure and the hose structure above the ground.

Abstract: A face equipment for mechanical extraction in longwall mining, in particular in the underground hard coal mining industry, includes a face conveyor (17) arranged along the mining wall, an extraction device (18) that can be moved along the face conveyor (17), and shield support frames (10) supported on the face conveyor (17) at an angle thereto. In order to determine the height of the face opening, a flexible hose level (21) with a liquid-filled hose (22) placed between the face conveyor (17) and at least one main component of the shield support frame (10) is installed in the area of the face conveyor (17). A pressure sensor (23, 24, 28) is arranged on at least one end of the hose (22). An inclination measuring device (25, 26) is arranged on the face conveyor (17) and on the main component of the shield support frame (10).

Abstract: A face equipment for mechanical extraction in longwall mining, in particular in the underground hard coal mining industry, includes a face conveyor (21) arranged along the coal face, an extraction mechanism (22) that can be moved along the face conveyor (21), and shield support frames (10) fastened at an angle to the face conveyor (21). In order determine the shield height of the extended shield support frame (10) corresponding to the face opening height, a flexible hose level (17) with a liquid-filled hose (18) is installed between the roof canopy (13) and floor skid (11) of individual shield support frames (10), and a pressure sensor (19) is arranged on the skid-side end of the hose (18). An inclination measuring device (25) is arranged on the roof canopy (13), and the pressure sensor (19) and inclination measuring device (25) are connected to an analyzing and control unit.

Abstract: A hydrostatic level-measuring system and related apparatus and method for measuring with precision, a level normal to gravitation of a physical surface, comprising: a plurality of N water-holding cups containing water and fluidically interconnected with one another and resting upon the physical surface, where N is greater than or equal to 2; each of the water-holding cups of comprising a cup height hn thereof from a bottom to a top of the cup which cup height hn is known a priori within acceptable measurement errors; and a micrometer system for measuring on an absolute or relative scale, a distance dn between the top of each the cup and the top surface of the water wherein a meniscus visible to a user is formed when the contact occurs and the meniscus is used to guide the measurement precision.

Abstract: The invention relates to a device and a method for determining the vertical spacing of objects while carrying out positioning tasks with a vertical travel portion.

Abstract: A hydrostatic sensor device and method is provided for detecting changes in elevation in pipes, boreholes, and tunnels below ground. A pressure transducer for sensing differential changes in fluid pressure is provided at one end of an extensible hose or other flexible conduit, while the other end is maintained in an equalizer tank at a reference atmospheric pressure at a given elevation. As one end of the system is moved along a grade, pressure changes at the transducer end relative to the reference pressure at the equalizer end are measured corresponding to elevation changes and are recorded against a distance scale, thus providing an accurate profile of the line surveyed.

Abstract: A lift measurement system is provided for determining a position of a load during a lift operation. The system includes a display that includes a scale and encloses a movable indicator that moves relative to the scale. A linkage is in communication with the load and the scale, such that movement of the load is translated to movement of the indicator relative to the scale to provide an indication of the position of the load. A plurality of displays and linkages may be installed at various load support zones such that the relative position of the corresponding indicators provides feedback related to the orientation of the load.

Abstract: An aid apparatus for level surveying instrument comprises a housing having a receiving chamber therein, two channels at opposite ends of the receiving chamber respectively, a window at one side of the receiving chamber, and a socket opening at the side wall of the housing connecting to receiving chamber via the channel. A controlling member is slidable received in the housing. The controlling member has a movable bar, two seal block disposed at opposite ends of the movable bar for sealing the channel, and a driving member is provided at the housing for driving the controlling to shift, whereby the sealing block being driven by the driving member to seal the channel and to depart from the channel to prevent bubbles formed in liquid.

Abstract: An aid apparatus for level surveying instrument comprises a housing having a receiving chamber therein, two channels at opposite ends of the receiving chamber respectively, a window at one side of the receiving chamber, and a socket opening at the side wall of the housing connecting to receiving chamber via the channel. A controlling member is slidable received in the housing. The controlling member has a movable bar, two seal block disposed at opposite ends of the movable bar for sealing the channel, and a driving member is provided at the housing for driving the controlling to shift, whereby the sealing block being driven by the driving member to seal the channel and to depart from the channel to prevent bubbles formed in liquid.

Abstract: A fluid-actuated level device for use, for instance, in the building trades, discovers points lying on a horizontal plane with a reference point. The level device has a tube with a referenceend and a working-end, and a housing unit attached to the reference-end. Electrodes in the housing unit measure fluid-levels in the reference-end. When the fluid-level in the working-end is positioned in the horizontal plane containing the reference point, then the level device emits a signal; in one embodiment, this signal is a single continuous sound. When the working-end is positioned slightly higher than the reference point, a second signal is emitted; in one embodiment, this signal is an intermittent sound. The second intermittent sound notifies the worker that the fluid-level in the working-end is too high relative to the reference plane, i.e., the worker has “overshot” the reference plane. Also provided are embodiments having a tube window, an alignment window, and a slidable backing assembly.

Abstract: A gauge for monitoring the relative height of two points comprises a generally tubular conduit extending from a first end thereof via a first limb thereof to a monitoring position spaced from the first end and via a second limb of the conduit from the monitoring position to a second end of the conduit in the region of its first end, two immiscible fluids of different densities, each in one of the first and second limbs with a mutual interface within the region of the monitoring position, means to vary the relative vertical positions of the monitoring position on the one hand and the first and second conduit ends on the other, and a pressure comparator to compare the pressures of the fluids at the conduit ends.

Abstract: A method and apparatus for hydrostatic leveling including a pair of liquid filled containers connected by a liquid hose for equalizing static pressure in the mercury pools in the indicating heads and a gas hose for equalizing the gas or vapor pressure within the heads above the mercury. Each head has an internal float with a display gauge. The indicating heads have identical structures and thus when they are resting on the level surface they may be reversed in location without change in gauge indicator reading; any difference in the reading is a measure of out-of-level condition. An elevator is used to support one head while a mobile tool is used to support the other head. The elevator comprises a rigid body that is secured to a stable structure adjacent the object to be leveled and includes a vertically displacable set-off for supporting the head. The mobile tool includes a level system for insuring consistent alignment of the head to the object being leveled.

Abstract: An apparatus for measuring the vertical displacement of a plurality of horizontally spaced locations on a variety of surfaces is disclosed. A fluid reservoir having a plurality of outlets is freely suspended on a support means, such as a tripod. A plurality of measuring means, at horizontally spaced locations, are connected to the plurality of fluid reservoir outlets. Each measuring means is then separately calibrated to a desired vertical height at its particular horizontal location to establish a reference point. Once the measuring means is calibrated, a single operator can determine to what degree a plurality of horizontally spaced locations are either higher or lower than the reference point. Additionally, a leveling apparatus is disclosed which also allows a single operator to determine the vertical displacements of a plurality of horizontally spaced locations.

Abstract: A hydrostatic system for measuring the elevation at two spaced locations. A first stand having a multi-leg base includes a toroidal tank slidably mounted on a shaft that extends through a tank central aperture. The legs include a bracket arrangement to permit securing each leg at an acute angle, an obtuse angle or parallel to the first stand. Thus, the tank can be positioned above or below the leg connection to measure high or low levels. A second stand includes a vertical transparent tube marked with linear distance indicia. A flexible hose connects the tank to the tube so that water (or other liquid) in the tank, hose and tube reaches the same level in both tank and tube. Two or more second stand, transparent tube and hose assemblies may be connected to the tank to permit simultaneous measurement of elevation at plural locations. The first and second stands and transparent tube may each be telescoping to increase the range of elevation measurements that can be accommodated.

Abstract: A level marking apparatus capable of directly measuring height comprises an elastic synthetic resin tube. One end of the tube is secured to a pressure sensor capable of producing an output voltage and air-tightly sealed, and the other end of the tube is connected to a reference instrument, which has a larger diameter and is shorter in length than the tube. The tube is totally filled with low viscosity macromolecule liquid. Moreover, the pressure sensor is connected to a micro computer programmed to find an average value of fluctuation waveform within a certain cycle of output voltage of the pressure sensor. The micro computer also calculates and memorizes a reference level based on a pressure difference between the reference instrument and the pressure sensor when placed at different heights. Additionally, a marking device is connected to the pressure sensor, and it is actuated by an ON signal from the pressure sensor.

Abstract: A level position measuring method including providing a hose having a first end and a second end; filling the hose, at least partially, with a liquid so as to form a water head; leaving the first end of the hose open to atmospheric pressure; closing the second end of the hose by airtightly fixing a pressure sensor to the second end of the hose near the water head; configuring the hose so as to define a reference level by obtaining a reference level pressure value dispatched from the pressure sensor; and measuring the level position by obtaining a level position pressure value dispatched from the pressure sensor which varies from the reference level pressure value in proportion to a vertical displacement of the second end of the hose.

Abstract: A level marking method including providing a hose having a first end and a second end; filling the hose, at least partially, with a liquid so as to form a water head; leaving the first end of the hose open to atmospheric pressure; closing the second end of the hose by airtightly fixing a pressure sensor to the second end of the hose near the water head; connecting a solenoid inker having an inking level to the pressure sensor, said solenoid inker being operated by ON and OFF signals dispatched from the pressure sensor and automatically drawing a mark at the inking level when it operates; configuring the hose so as to define a reference level by obtaining a reference level pressure value from the pressure sensor; arranging said pressure sensor such that it dispatches an ON signal at the reference level, and dispatches an OFF signal otherwise; and marking the level by vertically displacing the second end of the hose so as to cause the pressure sensor to dispatch an ON signal.

Abstract: An instrument set for plumbing or leveling and relative height setting of members such as posts or beams, each instrument including orthogonal sides and a feature projecting from the top of one side allowing each instrument to be set atop a respective post with the orthogonal sides against the post and a rabbeted feature on the bottom of one side allowing the instruments to be set atop a beam. Bubble levels on the sides of at least one of the instruments enable plumbing of a post or leveling of a beam, and open topped sight tubes attached to each instrument and interconnected with a water filled hose enable height setting with the same instruments.

Abstract: The invention is an improved level indicating and elevation indicating system using a hose containing fluid having a first and a second end, capable of being operated by a single person. An electronic method is used to indicate when a float at the first end of the hose is at, above, or below a reference. In the preferred embodiment, such indications are communicated through wires to three distinct lights at the second end of the hose, and a sight is used to determine accurately the position of a float at the second end. The preferred embodiment also includes a sleeve supporting the first end of the hose and a support for the sleeve. Also included are a vertical fixed rod for supporting the second end of the hose, a base for holding the fixed rod in virtually any position, and an adjustable rod (parallel to the fixed rod) for determining vertical offset distances. A pinching device, for slightly varying the volume of the hose, is also part of the preferred embodiment.

Abstract: A leveling apparatus includes at least two scales defined by enclosed receptacles, each having a cavity and a port into the cavity. Each receptacle also preferably has a top wall with a convex inner surface defining the top of the cavity. The top wall also preferably has a concave outer surface. The receptacles are connected through their ports in a common closed fluid communication system which is preferably only partially filled with a liquid sensitive to the levelness of a surface to be tested. The apparatus is spread across a surface whose levelness is to be tested, and the levelness is indicated by the relationships between the surfaces of the liquid in the scales and elevation indicating indicia on the scales as observed through the preferably concave top wall of each receptacle.

Abstract: A level vial includes a pair of elongated vessels, each having a top open end, a bottom open end and a transparent tube portion having a flat side wall extending between the top open end and the bottom open end. A flexible elongated pipe has two ends respectively connected to the bottom open end of the elongated vessels to communicate with the transparent tube portion so as to contain water therein. The transparent tube portion of the elongated vessels may be selectively vented with the ambient environment. A float restraining member is fixed to and extends inwardly from an inner wall surface of the transparent tube portion of each of the elongated vessels. The float restraining member is disposed adjacent to the top open end of the elongated vessel and defines an axial through hole. A floating article is provided in the transparent tube portion of each of the elongated vessels inwardly of the float restraining member.

Abstract: A vertical-difference measuring instrument comprising an entirely closed liquid system containing, as the only fluid, only substantially noncompressive liquid, the liquid system comprising a variable-volume reference reservoir and a sensing reservoir interconnected by a flexible hose, a flexible-walled gas container in the sensing reservoir and a pressure gauge connected in fluid communication with the flexible-walled gas container in the sensing reservoir for giving indication of the vertical distance between the reference reservoir and the sensing reservoir is disclosed.

Abstract: A device measures or controls a change of a level or a variation in a change of a level between several points. The device includes closed vessels (2) placed respectively at each of the points. The vessels are partially filled with a liquid (53) and are connected by liquid pipes emerging in their lower portion so as to form a liquid circuit (31) and by gas pipes emerging in their upper portion so as to form a gas circuit (36). Each vessel is equipped with a capacitive proximity sensor (11) placed above and at a distance from the upper surface (54) of the liquid which it contains and which provides a signal with respect to position in the vertical direction of a zone of the upper surface of the liquid in the vessel. A device comprises the signals provided by the sensors so as to be able to provide data with respect to the vertical position of the vessels and, consequently, with respect to the points relative to one another or relative to a reference vertical position.

Abstract: A level vail includes a pair of elongated tubes, each having a top open end and a bottom open end. A pipe has two ends, respectively connected to the bottom ends of the elongated tubes. Water is contained in each of the elongated tubes, in each of which a floating article is also provided. A communicating member is provided on the top open end of each of the elongated tubes. One communicating member has at least one passage which communicate the interior of the elongated tube and the external atmsophere. A blocking member is movably disposed in the communicating member so that the passage of the communicating member can be opened and closed selectively.

Abstract: A device for measuring the pressure difference between the two ends of at least one flexible tube connecting together the positions occupied by two elements. In a preferred embodiment, to a summing circuit are applied the signals delivered by two differential pressure sensors disposed respectively at the two positions and to which are applied the pressures prevailing in two flexible tubes, one containing a fluid of a density greater than that of air and the other containing air, these two tubes joining together the respective inputs of the two sensors. An accumulator maintains the static pressures prevailing in both tubes equal. The device is accurate and practically insensitive to temperature variations and accelerations.

Abstract: An open circuit measuring system (10) for discerning the vertical distance between selected locations is provided. The system includes first and further members, each having a base portion (14) with a bottom (16), and an upright tube (18) which contains liquid. The tube (18) is open at its top, and extends upwardly from the base portion (14). Fluid communication is provided between the tubes proximate their lower portions (22). A scale is carried by the tubes along their lengths, such that a user can discern, as marked by the level of liquid in the tube (18), the distance in selected units of measure between the bottoms of the first and further base portions.

Abstract: The method of facilitating putting a golf ball into a cup on a sloped green comprises providing a pair of right angularly related float levels within a hollow frame with each float level having an axis, index marks and a sighting rod in the frame; orienting the frame to a first upright plane at eye level while visually aligning the sighting rod, ball and cup maintaining the frame at right angles to the line of sight, and angularly adjusting the axis of the first level parallel to the transverse slant in the green. A further step includes noting the position of the buble in the first level relative to its central index to selectively indicate the extent and direction of slope of the green. The location of the bubble defining the ball stroking path which with the correct stroking force will assure a curved path of travel into the cup.

Abstract: A clinometer releasably securable to a golf club head to indicate its loft and to detect its lie. The clinometer has a sector shape and its circumferential extent is sixty degrees of arc. An arcuate bubble tube having accompanying indicia to indicate differing angular orientations of a club head face is secured to the arcuate top wall of the device and a straight bubble tube extends horizontally from a flat sector shaped wall to show the lie of the club head.

Abstract: The trailing drum of a double-ended ranging drum shearer is steered in a seam by producing an algorithm which determines, as a result of information derived from signals from the machine dependant on its tilt, direction and amount of movement along a face being cut. The height of the leading drum is used as a reference from which to determine the optimum position of the trailing drum in order that a constant quality of desired mined material is obtained.

Abstract: A trailer measuring system (10') for leveling a trailer during setup and for indicating deviations from an initial position of level of a trailer is provided. The device (10') includes a reservoir (16') and a plurality of measuring tubes (18') which can be secured to the frame (12) of a trailer (14) at horizontally spaced locations. Fluid communication is provided between the measuring tubes (18') proximate their lower end portions by tubing (20') and between their upper end portions by tubing (22) which connects the measuring tubes (18') in series or series/parallel to form a closed system. Fluid communication is selectively provided between the upper and lower end portions of the measuring tubes (18') and the upper and lower portions of the reservoir (16'), respectively.

Abstract: A spirit level assembly attachable to a free end of a pipe section being installed includes a housing block of generally rectangular cross-section in which a series of viewing ports are formed through opposed side walls thereof. Fitted into each of the viewing ports is a spirit level vial or bubble. Integrally formed on the opposed ends of the housing block are cylindrical stubs of predetermined diameter corresponding to commonly encountered pipe sizes. The stubs are threaded in accordance with the National Pipe Thread convention. When the housing is screwed onto the length of pipe being leveled or plumbed, an appropriate bubble vial can be viewed to establish the desired horizontal or vertical orientation of that pipe segment.

Abstract: Displacement sensors which are communicated with a stationary reference side are placed at the measuring points of a large structure. Displacement at each measuring point is electrically measured by utilizing the fact that the liquid levels at the stationary reference side and each measuring point are at the same level.

Abstract: Centering a log by determining the location of a selected axis through the log relative to a fixed replicate axis. The log is pinned and each end is provided with double pivots. Pivoting the log about one pivotal axis spaced from the replicate axis determines a pathway around that axis. Pivoting the log about the other pivotal axis sweeps the log end and, accordingly, the selected axis across the determined pathway. The selected axis is positioned on the pathway by pivoting the log about said other axis and it is positioned at the replicate axis by pivoting the log about the first pivotal axis.

Abstract: A height level measuring device is provided and consists of an elongated transparent flexible hollow tube with scales at each open end thereof. A predetermined amount of liquid is placed within the tube so that the liquid will seek same height level at both ends no matter what height the ends are raised to, thus allowing height of two objects to be vertically measured when there is an obstacle between the two objects.

Abstract: A liquid level comprising a bottle for holding leveling liquid and means in its lower end for connecting to a length of hose. The bottle has a filler opening in its upper end and integral means for storing the hose around the bottle. The level may include a ventable bottle closure over the filler opening and a ventable hose closure detachably mounted on the extended end of the hose. The bottle may also include an integral clip on the outside surface of the bottle for receiving and holding an end portion of the hose. The bottle may have an integral handle on one side thereof and a mounting plate attached to the other side thereof.

Abstract: The invention relates to a level indicating device including a container or reservoir and a length of tubing extending from the container near the bottom thereof. Narrow, inverted cups are adhered to the sides of the container so that they may be slipped over the top of a stake driven into the ground to provide a firm, stable support for the container while the tubing is moved to different locations to establish a reference horizontal plane.

Abstract: A leveling instrument is provided with a flexible length of tubing extruded with a pair of thin-walled, balloon-like diaphragms at opposite ends thereof. The tubing contains a flow passage filled with liquid in communication with atmospheric pressure acting upon the liquid through the diaphragms. The liquid provides a leveling medium for the instruments for establishing the level of one location with respect to another location. A method of manufacturing the leveling instrument is also disclosed.

Abstract: An instrument for establishing a horizontal plane for leveling ceilings, tables, floors and the like, consisting of a reference head having a translucent liquid reservoir, an adjustable field head, and a hose for interconnecting the two heads. With the level of liquid in the reservoir calibrated to correspond to the desired elevation, the liquid level at the field head at the other end of the hose will correspond to the selected reference level, thereby providing a means for defining a horizontal plane which is independent of a continuous line of sight. A plurality of datum scales in visual juxtaposition with the reference head reservoir and correlated to the mounting channel or to the base of the reference head provide reference marks at known vertical distances from these mounting points.

Abstract: A structure leveling sytem comprises a plurality of portable members each including a base having a bottom and a transparent tube open at its having a bottom and a transparent tube open at its top and upstanding from the base and provided with graduations at intervals along its length. The graduations on all tubes correspond, whereby like graduations on the tubes denote identical distances above the bottoms of the bases. The system also comprises flexible tubing interconnecting the bottoms of the tubes with each other. Liquid, such as water, is introduced into the system through the top of one of the tubes and the structure to be leveled in manipulated until the liquid level in all tubes is at corresponding graduations, thus denoting that the bottoms of the bases are at a common elevation and hence that the structure is level.

Abstract: The present leveling device is operable with a hemodynamic pressure measuring system which includes a pressure catheter to be implanted in the body of the patient and pressure measuring device connected by a tube to the catheter and supported on a vertically movable support platform. The present automatic leveling device operates to automatically maintain the pressure measuring device at the same level as the catheter implanted in the patient and includes a tube level with one end being connected to the patient and at the same level as the catheter implanted in the patient and with the other end being connected to the vertically movable support for the pressure measuring device. A sensor is associated with the tube level and is operable in response to vertical movement of the catheter implanted in the patient to automatically raise and lower the vertically movable support for the pressure measuring device in response to vertical movement of the catheter implanted in the patient.

Abstract: A leveling device includes a first and second pressure cell that are interconnected by lengths of fluid filled, flexible tubing. Each of the pressure cells is associated with a strain gauge for sensing the differential pressure of the fluid between a region associated with each of the tubing lengths. An indicating means associated with the strain gauges indicates, in response to a differential in fluid pressure sensed by the strain gauges, the elevation of either of the pressure cells relative to the position of the other cell. In one form of the invention, provision of a single tubing conduit between the strain gauges reduces the probability of erroneous measurements due to pressure fluctuations within the tubing. In alternate forms of the invention, an agitating means is associated with flexible bellows structure coupled to the tubing so that hysteresis of the fluid is substantially reduced.

Abstract: Apparatus for Levelling a surface, such as a table, includes several bellows containing a fluid connected to the surface, conduits connecting the bellows together and a control valve for connecting or disconnecting the conduits, the control valve being located in a chamber and being separated from an actuator by a diaphragm.

Abstract: A magnetic probe for detecting the location of a magnetic anomaly. The probe includes an outer dewar jacket that defines a chamber maintained at cryogenic temperatures by a helium reservoir. Mounted on the reservoir in the chamber is a substrate which supports a plurality of pairs of gradiometer coils and a magnetometer. A plurality of SQUIDs detect the magnetic fields sensed by the magnetometer and the pairs of gradiometer coils to determine the magnetic field intensities, directions and gradients from which can be determined location, speed and direction of the anomaly. A valving network connecting the reservoir to a vent allows the probe to be operated in any orientation around its horizontal axis.

Abstract: A level constructed of clear acrylic plastic including a piece of colored acrylic plastic which serves as a light collector and a continuous passageway in the clear acrylic which reflects the light collected by the piece of colored plastic. By partially filling the passageway with liquid, a line of reflected light appears on the wall of the passageway above the interface between the liquid surface in the passageway and the unfilled portion of the passageway, whereby the level is easier to read than ordinary bubble type levels.

Abstract: A device (10) for measuring the difference in elevation between first and second substantially horizontal surfaces (12a, 12b) includes first and second chambers (10a, 10b) respectively located on the surfaces (12a, 12b). The chambers contain quantities of a fluid such as mercury (116) and are coupled together through a conduit (20) which enables mercury (116) to flow between them as required, so that the mercury levels in the chambers will be in the same horizontal plane. A first device (140a) is mounted at a first distance above the fluid in the first chamber and at a fixed distance above the first surface (12a). Likewise, a second device (140b) is mounted at a second distance above the fluid in the second chamber, and at the same fixed distance above the second surface (12b).

Abstract: A high-sensitivity device for measuring the mutual level differentials among a certain number of reading locations, the device comprising a plurality of containers, one for each reading location, mutually connected at the bottom ends by a piping opening into a balancing tank which holds a liquid mass. Each container is equipped in its interior with a float which is held spaced apart from the container walls by flexible retaining members, a level-differential sensitive transducer being mounted in correspondence with the walls. The apparatus further comprises a device for measuring the signals delivered by the transducers.

Abstract: A bubble level has at least two position sensing devices, such as mercury switches, disposed at right angles to each other and connected in a circuit having a three-position switch and an audio indicator, such as a buzzer. When the level is to be used to determine horizontal alignment, these switches move to a first position causing a horizontally disposed one of the position sensors to be cut into the circuit, while simultaneously cutting out the other position sensor. When the level is horizontally aligned, which may be in a position not in full view of the user, the position sensor completes the circuit and causes the audio indicator to sound. When the level is to be used to determine vertical alignment, the switch is moved to a second position, which cuts out the horizontal position sensor and cuts in the vertical position sensor and the same procedure can be undertaken. The switch has a central off position.

Abstract: A first rod includes a relative elevation scale and a first fluid container vertically adjustable with respect to the relative elevation scale to a position corresponding to a desired elevation relative to the base of the first rod, and a second rod includes a second fluid container of substantially lesser cross sectional area than the first fluid container, a predetermined level of fluid in the second fluid container indicating that the base of the second rod is at a desired elevation relative to the base of the first rod.

Abstract: A level device is designed to determine different levelling points in building work to automatically set certain parts, such as the suspension systems for false ceilings when this apparatus is fitted with a bolt-driving attachment, comprising a flexible tube connected to a first chamber closed by a first diaphragm offering very low resistance to the liquid contained, the other end of the tube connected to a second chamber closed by a second diaphragm which second diaphragm offers resistance to the liquid contained and compresses the air contained in the corresponding space whereby in turn this air actuates a diaphragm which has needle-type contact switches, on each side, these circuits to an indicator, with a valve used to locate the apparatus at a point which may be at a higher or lower level than that determined by the first diaphragm.

Abstract: An adjustable water level device which may be used to match an unknown level to a reference level. The reference level may be easily adjusted by sliding a transparent cylinder inside an outer foam lined cylinder. An additional biasing spring is provided to assure safe movement of the transparent cylinder. The adjustable water level device may be attached to a vertical surface by driving nails or screws through openings in a supporting bracket or may be attached using hook and loop pile fastener type material. An offset bracket is provided so that the adjustable water level device may be mounted in the presence of obstacles such as wall moldings.

Abstract: A flap holster with the flap pivotally and removably secured to either side of an ambidextrious holster. The holster inlcudes an opening for the insertion and removal of a handgun and a transverse slot below the opening on each side. The flap is pivotally connected to one side of the holster and extends over the handgun opening. On the underside of the flap, an extensible strip is secured at one end to the flap and includes an end hook at the opposite end to engage one of the transverse slots and secure the flap in place. The extensible strap is preferably captured in a fabric tunnel in the underside of the flap. An inextensible flexible strap is secured at both ends to the extensible strap to limit its extension length to avoid over stressing its elastic properties. The hook is preferably a reverse directed tab dimensioned to slip into the transverse slot allowing the elasticity of the extensible strip to hold the flap closed.