Abstract: A hardness tester for a large test material is downsized by shortening a stroke length of the x-y stage. A hardness tester in accordance with the invention transfers the laser irradiating unit 70 two-dimensionally along the X or Y axis and irradiate a laser beam on the material W under test placed on the stage 10. The tester also monitors the laser beam visually and determine a target position to be measured and transfers the monitoring unit 45 to the determined target position along the X or Y axis and monitor the position by means of the monitoring unit 45. If the position does not fall on a boundary between crystals, the loading unit 55 is two-dimensionally transferred and forms a dent on the position by means of the penetrator 55a. An image of the dent is captured by the monitoring unit 45 and the hardness is determined by calculating a diagonal length of the dent by image processing.

Abstract: A method for calibrating an apparatus for calibrating a hardness tester, the method comprising the steps of: setting a plurality of calibration points between a rated force point at which a rated force of a force measuring member is applied and a zero point at which no-load is applied, for measuring outputs (mV/V) from the force measuring member according to test forces(N) applied to the force measuring member; and calculating a relation between the test forces(N) and the outputs(mV/V) as an approximation based on the test forces(N) and the outputs(mV/V) according to the test forces(N) at the calibration points. An apparatus for evaluating a dynamic characteristic of a specimen, which installed in a hardness tester, the apparatus comprising: a force measuring member; a force transmitting portion which is movable up and down; a distance measuring member incorporated in the force transmitting portion to be contacted with the force measuring member from above; and an indenter.

Abstract: A hardness tester having a frame and a rotatable turret movably supported on the frame is provided. A plurality of load cells are fixedly mountable on the turret, and a plurality of indenters are fixedly attachable to the load cells, respectively. A user interface selectively provides signals to a motor to move the turret into contact with a test specimen via one of the indenters to thereby apply a load on the test specimen. The indenters are fixed with respect to the turret and do not move in relation to the turret when the turret is brought down to bear on the test specimen. The load cells measure the load applied to the test specimen. A closed loop control system receives load measurement signals from the load cells and controls movement of the turret, preventing the motor from applying load in excess of a predetermined selectable load amount input by a user via the user interface. The invention preferably includes a plurality of indenter adapters, each attached to respective undersides of the load cells.

Abstract: An indentation measurement apparatus is retrofittable onto any of a variety of load-applying frames and includes a mount for mounting an indenter of any geometry (for example blunt or sharp). The arrangement is very stiff and mechanical values including Young's modulus, strain hardening exponent, yield strength, and hardness can be obtained from a single load/unload versus displacement test. A wide variety of materials can be tested using the apparatus. An optical probe can measure displacement of the indenter head relative to a sample. A new method of calculating strain hardening directly from load/displacement measurement is presented as is a new method of calculating strain hardening exponent.

Abstract: Disclosed in an apparatus for measuring positively-sensed force of an electrical connector, comprising: a base plate; at least one L-shaped pads, the two L-shaped pads being each affixed to the base plate at an upper end thereof in such an arrangement that ends thereof oppose each other; an elastically deformable sheet provided between the two L-shaped pads, the elastically deformable sheet being affixed to the base plate and formed with a projective measuring region at end thereof; and at least one strain gauge inertly affixed to the elastically deformable sheet, the strain gauge beingconnected to a signal transmitting device that outputs strain value of the strain gauge to a signal amplifying device for display purpose in response to deformation of the elastically deformable sheet.

Abstract: A method and apparatus for testing structural integrity of a building material. Examples are given for testing the structural integrity of substrate behind synthetic stucco and stucco. The tester has an exposed elongated pointed tip that reciprocates within a casing that is electrically insulated from the pointed tip for safety. The pointed tip has a pointed end with an inclusive angle of sixty degrees. A spring forcibly opposes movement of the pointed tip into the casing, and a scale on the casing shows the maximum force exerted by the spring to the pointed tip. As the pointed tip is pushed through Exterior Insulation and Finish System ("EIFS") synthetic stucco to the substrate sheathing therebehind, an indicator shows the force applied by the pointed tip to the substrate sheathing.

Abstract: A plunger apparatus is presently disclosed that includes a housing, and a probe slidably supported by the housing. A damping assembly is supported by the housing and cooperating with the probe. The housing, preferably, has a proximal portion and a distal portion wherein the probe is slidably mounted within the housing and extending axially from the distal portion. The probe, desirably, has an increased diameter portion at a proximal end thereof and a penetrating tip adjacent a distal end thereof. A hammer mechanism is provided that is slidably supported by the housing and cooperatively engaging the probe and cooperating with the damping assembly. The housing may also include a handle assembly. A method for using the plunger apparatus is also disclosed.

Abstract: An apparatus for testing hardness of a pipe including a body having a longitudinal axis, a probe connected to the body and extending transverse to the longitudinal axis of the body, a retaining mechanism connected to the probe and positioned within the body so as to maintain the probe in a fixed position relative to the pipe while the body is moving through the pipe, and a processor connected to the probe so as to convert a signal produced by the probe relative to the hardness of the pipe into a humanly perceivable indication of pipe hardness. The probe serves to contact a point along the inner surface of the pipe while the body is moving continuously through the pipe.

Abstract: A method for testing the stability of installed wooden utility poles in a non-destructive manner, in particular to determine decay caused by fungal growth or insect infestation. A quantity E' that is proportional to the modulus of elasticity E of the utility pole is measured above ground level at at least two different heights which are spaced apart by at least one meter, one height being directly at ground level, by shooting a pin with a defined energy at the utility pole and measuring its deflection when it springs back. The conditions of stability are fulfilled when the quantities E' measured at different heights deviate from one another by less than 30%. The invention enables one to objectively assess the condition of utility poles as well as to quantitatively characterize this condition.

Abstract: An air hammer type impact tester including a machine base having a pressure accumulation chamber with an air inlet, a straight tube vertically suspending in the pressure accumulation chamber, a test platform mounted on the machine base and having a replaceable buffer block adapted to support the sample to be tested, a hammer block moved in the straight tube to strike the buffer block against the test sample, an air pump operated to pump air into the pressure accumulation chamber, a diaphragm moved between the bottom end of the straight tube and the air inlet of the pressure accumulation chamber, the diaphragm being forced upwards by compressed air to close the bottom end of the straight tube when compressed air is pumped from the air pump into the pressure accumulation chamber, the diaphragm being forced downwardly away from the bottom end of the straight tube by air pressure when the inside pressure of the pressure accumulation chamber surpasses a predetermined value, permitting the inside pressure of the pr

Abstract: A method and apparatus for determining the degree of dynamic hardness of a material, such as a sporting equipment item. The method includes the steps of impulsively exciting a surface of the material by impacting the surface against a second, relatively hard surface in contact with a force-measuring device, and then measuring a signal from the force-measuring device to determine a frequency-dependent spectrum of the force exerted by the excited surface on the second surface. From this data, a roll-off frequency is measured and then analyzed to determine the degree of dynamic hardness of the material.

Abstract: Arresting material test apparatus, test probes and test methods enable testing of compressive gradient strength of cellular concrete, and materials having similar characteristics, on a continuous basis from the surface of a section to a typical internal penetration depth of at least 60 percent of thickness. Previous testing of cellular concrete typically focused on testing to confirm a minimum structural strength prior to structural failure or shattering of a test sample. For an aircraft arresting bed, for example, cellular concrete must exhibit a compressive gradient strength in a relatively narrow precalculated range continuously from the surface to penetration depth equal to 60 to 80 percent of sample thickness. Precalculated and controlled compressive gradient strength is critical to enabling an aircraft to be safely stopped within a set distance, without giving rise to drag forces exceeding main landing gear structural limits.

Abstract: Methods and apparatus for the accurate determination of impact fracture behavior of materials. Test specimens are thermally preconditioned in-situ by flowing a thermally conditioned gas over the surfaces of the specimen which contain the volume of material near the notch and/or precrack which influences the fracture properties. Upper shelf energy is determined using miniature specimens which is quantitatively equivalent to the upper shelf energy which would have been obtained using conventional ASTM E 23 specimens. Percent shear fracture area and lateral expansion are measured using a computerized image capture system to reproduce a digitized image of the fracture surface on a computer which is then quantitatively analyzed. A high frequency response load cell, consisting in part of two active strain gages installed near the center of percussion on the tapered portion of an impact striker, well within one stress wavelength of the striking surface, is used to measure the force-time curve.

Abstract: A portable test hammer apparatus that produces repeatable and adjustable impacts to make traditional "tap testing" more reliable and quantified. The apparatus includes an impactor head device having a housing sized to be held in a human hand and engageable with the structural member, a plurality of adaptor bases, each readily mounted on the housing, an impactor head disposed within the housing for reciprocating movement therein, and a fluid piston assembly for moving the impactor head from a retracted position within the housing to a projected position in which the impactor head impacts the structural member. Impactor devices can be rapidly slid across test surfaces on non-marring feet, vacuum adhered to the test surface, or both. The apparatus further includes a rugged acoustic transducer for generating and transmitting an electrical signal based on the acoustic signature of the strike of the impactor head against the structural member.

Abstract: The present disclosure concerns a ground vibration properties detection method by generating a specified vibration load equal to the actual load generated by traffic vehicles on a paved road or by generating a specified vibration load corresponding to a seismic intensity of earthquake on a ground and measuring the vibration load as a vibration level induced by the vibration load and equipment thereof.

Abstract: A hardness tester is disclosed which conducts its hardness test through a penetrator impinging upon the surface of a test specimen. Enhanced accuracy and repeatability is achieved through the use of a closed loop system and directly mounting a load cell to the indentor, connecting a linear displacement transducer directly to the load cell and eliminating an elevating screw in initially positioning and applying load to the specimen to be tested.

Abstract: A method is provided for determining the fracture toughness of a material based upon observation of crack opening displacement (COD) as a function of distance from the tip of a crack generated in the material. An apparatus is also provided for generating a crack in a material for subsequent fracture toughness determination.

Abstract: The dynamic pyrotechnical penetrometer enables to determine the features of the soils by continuous detection and measurement of penetration of a probe rod (1) using the pressure created by a pyrotechnical gas generator (5). A standard probe rod (1) mounted on a piston (2) is placed in an amagnetic tube equipped with solenoids. This probe rod accommodates a magnet (3) on the one hand and a recoiling mass (4) on the other, which balances the amount of movement of the rod created by the gases of a pyrotechnical generator (5) contained in this recoiling mass. A unit for acquiring and processing the movement of the standard rod enables to calculate the resistance of the soil to the penetration of the rod.

Abstract: A force, weight or position sensor unit and sensor element in a first embodiment. In a second embodiment, the sensor element of the first embodiment is incorporated into an apparatus for microindentation hardness testing and surface imaging which allows immediate imaging of the surface subsequent to hardness testing. The sensor uses a multi-capacitor system having drive and pick-up plates mounted on an appropriate suspension system to provide the desired relative motion when a force is applied to the pick-up plate. The output signal is run through a buffer amplifier and synchronously demodulated to produce a signal proportional to force or displacement. The sensor element is mounted on a scanning tunneling microscope base and a sample mounted on the sensor.

Abstract: A method for measuring dynamic hardness of elastic materials is applied particularly to determining the state of tonal quality for a piano hammer. The method includes selecting a piano hammer of predetermined type from a set of piano hammers, causing the selected piano hammer to strike against an impact surface having the form of a piano string or string grouping appropriate to a piano hammer of the predetermined type, measuring one or more elements of force and motion of the piano hammer striking the impact surface, e.g. force, determining, e.g., the cut-off frequency of the power spectrum for the selected piano hammer striking upon the impact surface, and comparing the determined cut-off frequency of the power spectrum for the selected piano hammer against a predetermined range of cut-off frequencies of power spectrum acceptable for piano hammer of the predetermined type. An apparatus for testing is also described.

Abstract: A system and method for identifying a route for excavation of an underwater trench on the seafloor includes a surface vessel, a plurality of penetrometers and an onboard computer. As the surface vessel plies along a proposed route for the underwater trench, penetrometers are launched from the vessel at selected launch points. Upon impact of a penetrometer with the seafloor, acoustic signals transmitted from the penetrometer during the impact event are analyzed by the onboard computer. From this computer analysis the seafloor at the impact point is classified as being in either a first state indicative of proceeding along the proposed route or a second state necessitating a deviation from the proposed route. Depending on the state of the seafloor and the number of deviations needed, the proposed route is returned to and followed, or a new proposed route is established. Data from the impact events are subsequently compiled to establish an actual route for excavation of the underwater trench.

Abstract: The invention pertains a method of determining elastic and plastic mechanical properties of ceramics, intermetallics, metals, plastics and other hard, brittle materials which fracture prior to plastically deforming when loads are applied. Elastic and plastic mechanical properties of ceramic materials are determined using spherical indenters. The method is most useful for measuring and calculating the plastic and elastic deformation of hard, brittle materials with low values of elastic modulus to hardness.

Abstract: Centering devices are provided for use with Brinell hardness measuring instruments, particularly electro-optical probes, which include one or more illumination sources in a housing having an aperture at one end which is aligned with an optical axis of the probe to provide the optics a view of the specimen surface opposite the opening. In one embodiment, a spider-like centering structure is provided protruding through the probe end opening. The centering structure directs light from source in the probe directly into an indentation in a specimen surface engaging the centering structure and prevents light from crossing the indentation and reducing edge contrast. A mask further prevents spillage of light from each source onto the specimen surface adjoining the indentation and the source so as to heighten contrast differences between the bright surface of the indentation and the dark surrounding specimen surface.

Abstract: A device for testing a specimen for the purpose of ascertaining strength of an edge or hardness of a surface employs a pivoted rocker arm whose two extremities are interactive with voice coils that impart a controlled torque and velocity to the rocker arm. A diamond indenter and a linear variable differential transformer displacement gauge (LVDT) are also attached to the rocker arm, The torque produces a corresponding force on the indenter. A holder positions the specimen opposite the indenter, The degree of indentation produced in the specimen at two different force levels is measured by the LVDT.

Abstract: A method for measuring dynamic hardness of elastic materials is applied particularly to determining the state of tonal quality for a piano hammer. The method includes selecting a piano hammer of predetermined type from a set of piano hammers, causing the selected piano hammer to strike against an impact surface having the form of a piano string or string grouping appropriate to a piano hammer of the predetermined type, measuring one or more elements of force and motion of the piano hammer striking the impact surface, e.g. force, determining, e.g., the cut-off frequency of the power spectrum for the selected piano hammer striking upon the impact surface, and comparing the determined cut-off frequency of the power spectrum for the selected piano hammer against a predetermined range of cut-off frequencies of power spectrum acceptable for piano hammer of the predetermined type. An apparatus for testing is also described.

Abstract: An apparatus and method for measuring the firmness of a paper roll product. The roll product is mounted on a spindle and a plunger is lowered into engagement with the outer peripheral surface of the roll product. A motion detector detects the distance the plunger moves into the roll product under the weight of the plunger and data based on this distance is displayed for viewing by the operator. Calibrating gauges are employed prior to measurement to ensure that a zero reading on the display corresponds to the point at which the plunger initially contacts the roll product outer surface.

Abstract: A method and apparatus of measuring the hardness or various other characteristics of a sample surface, comprises a load cell carrying a penetrator and connected to a computer for reading signals from the load cell. The sample is advantageously mounted on the vertically moveable table of a microscope. The table can be moved by a stepper motor also connected to the computer for raising the sample into contact with the penetrator until a preselected force is reached. The force is sufficient to indent the sample surface with the penetrator. Optical or other mechanisms can then be used to measure the indentation. One other mechanism which can be used to measure the indentation is a second load cell carrying a tube which also contacts the sample surface and produces a second signal. Signals from the two load cells can be processed to measure a difference between the signals which provides a measurement of the indentation produced by the penetrator.

Abstract: The reliability of mechanical testing of the hardness of cigarettes with one or more pivotable weights is enhanced by modifying the results of such testing on the basis of signals which are obtained by optically scanning the diameters of successive cigarettes prior to mechanically induced deformation. Optical scanning is carried out by triangulation with a fixedly mounted measuring head. The signals which are obtained with mechanical testing can be further influenced by taking into consideration the moisture content and/or the temperature of tobacco in tested cigarettes.

Abstract: A hardness tester includes an indentor which is mounted to a linearly guided carrier movably supported in a frame, with a linkage mechanism being attached to the carrier for transmitting the load onto the indentor. Interposed within the linkage mechanism is a force gage which converts the force exerted thereupon into an electric variable and is operatively connected to a comparator circuit by which the electric variable generated in the force gage is compared with a preset, selectable desired value. The comparator circuit includes an output which controls a drive unit which in turn is connected to the linkage mechanism by which the load upon the indentor is exerted.

Abstract: A means of testing used tennis balls by inserting them between a compression arm with a pressure point midway of the ball and a base with backstop which also engages the ball. The weighted compression arm is allowed to fall on the ball and a reading is obtained at the forward end of the tester to determine if the ball is playable, practicable or should be discarded.

Abstract: In an indentation hardness tester a specimen placed on a specimen table is brought to a position just under an indenter mounted on one free end of a balance having its fulcrum received by a fulcrum bearing member, the balance is turned about the fulcrum by a test load to make an indentation in the specimen by the indenter and then the size of the indentation is measured through a microscope including an objective lens. The fulcrum bearing member for receiving the fulcrum of the balance is vertically movably mounted on a stationary part so that the indenter mounted on the balance is brought up from or down to a position right above the specimen table in close proximity thereto, and the microscope or at least its objective lens is pivotally mounted on the stationary part so that the objective lens turns to or turns away from a position right above the specimen table.

Abstract: An apparatus and process is provided for testing the hardness of paper rolls. The apparatus includes a tester that is selectively moveable across a roll of paper. The tester includes an impact anvil which strikes the paper at a selected frequency and which determines the hardness of the paper roll based on forces encountered by the impact anvil. The tester further includes an encoder wheel for identifying relative positions on the paper roll at which each test is performed. The impact anvil and the encoder wheel are operatively connected to a computer which receives signals and calculates hardness at each of the plurality of positions tested. The computer provides output of data on the most recent traversal of a paper roll and on plural sequentially tested rolls to assess trends in the hardness of paper rolls produced by a particular machine.

Abstract: A process and device for revealing impact(s) received by a substrate make use of a film capable of being deposited onto said substrate and consisting of a matrix in which are embedded microcapsules intended to be broken during the impact and thus to release product(s) which they enclose and which is (are) endowed with different photoluminenscence properties according to whether it is (they are) encapsulated or released into the matrix.

Abstract: A device for applying therapeutic or analgesic pressure quantitatively which includes a sensor for continuously measuring the pressure on a patient's skin and underlying tissue. The instrument includes a hand-held force sensitive transducer having a blunt tip extending therefrom. When the blunt tip of the device is pressed against the skin thereby compressing the underlying tissue, the transducer yields an electrical signal proportional to the applied pressure. This signal is then fed to a resettable digital display. When the pressure applied to the skin reaches a threshold value, an actuator switch is actuated starting a timer which measures the elapsed time period during which the skin and underlying tissue is exposed to the measured pressure. An optional alarm indicates when the combination of pressure and elapsed time has reached a previously determined level.

Abstract: A method of testing the hardness of a workpiece having a continuously curved outer surface, in particular a pipe or rod, by the penetration method, includes (a) holding the workpiece in a horizontally and vertically fixed position; (b) arranging a machine tool and a hardness testing instrument having a penetration body above the workpiece for movement with respect to the workpiece; (c) linearly scanning a predetermined area of the curved surface of the workpiece for determining the distance between a distance sensor and the curved surface, the region lying in the horizontal path of the machine tool; (d) determining the summit point of the scanned curved surface area from the scanning operation of step (c); (e) selecting the scanned curved area as the test location for the horizontal positioning of the hardness testing instrument; (f) selecting a locus along the scanned curved area of the workpiece as the reference point for the vertical positioning of the machining tool; (g) machining a region into the surfac

Abstract: A microhardness tester comprises a turret capable of holding a plurality of load rod assemblies such that, when the optical objective elements mounted on the turret have been properly aligned with respect to the indenter of one load rod assembly desired to impinge upon a specimen to test for microhardness and it subsequently becomes desirable to use a second load rod assembly to change scales for the testing, it is only necessary to properly align the indenter of the second load rod assembly and not the objective elements with the test specimen. The load rod assembly of the microhardness tester free falls in its testing mode, and a spring is provided for retaining the load rod in a home position spaced away from the test specimen. Thus, the load weights applied to the load rod as carried to the test specimen are not affected by spring load tolerances such that weight calibration can be completed during the weight manufacturing process.

Abstract: A method of inspection of structures in which a hammer capable of imparting a non-destructive impact to an object to be inspected and provided with a pressure sensor or an acceleration sensor is hit against the object and, from a signal then put out, a processed signal of the time during which the hammer is in contact with the object or of the waveform signal during such time is displayed, apparatus provided with a signal processing device for the measurement of the above time, and apparatus provided with a device for removing an impact driving force responsive to a signal put out when the hammer contacts the object, for the measurement.

Abstract: A method for determining the micro impact energy capacity of a disk drive's ceramic heads and its thin film disks. The impact energy capacity of disk drive heads (typically composed of ceramic materials) and disks (higher capacity disks use thin film media) provides a measure of quality and durability of the heads and media. The method includes dropping an indentor of a known weight on a sample surface, measuring the identation surface area and length, increasing the weight and repeating the previous steps at different areas o the surface until surface cracking occurs. The various measurements are plotted to produce a stress-strain curve, the area of which comprises the micro energy capacity of the surface.

Abstract: A driving device for a hardness measuring instrument of the type including a fixed structure (2,3,4,5,6) having a base on which a piece to be controlled is firmly resting, and a movable assembly (7,8,9,10) that is driven from a motor (6) during a measuring cycle in such a manner as to be initially brought nearer the piece to be controlled and subsequently subjected to a measuring load, wherein the device utilizes, between the motor (6) and the movable assembly (7,8,9,10), two coaxial screws (11,13) having equally running threads, one of which screws is a large-pitch screw (11) and the other one is a small-pitch screw (13), the two screws being driven from the motor (6) and being arranged so that during a measuring operation, first the large-pitch screw (11) acts to cause the movable assembly (7,8,9,10) to be rapidly moved towards the piece to be controlled and then the small-pitch screw (13) acts to cause said movable assembly to be brought nearer said piece by a slow powerful motion, the reverse procedure ta

Abstract: A bar device has one end portion supporting a test body and is pivotable about a pivot center. The bar device comprises a measuring device together with a probe, which works on the basis of measuring the thickness of thin layers. An energizing means acts on the bar device and comprises a first part rigid with a housing and a second part rigid with the bar device. A geometric first longitudinal axis passes through the center of the probe and the center of the test body. The part rigid with the housing comprises a cylindrical electromagnetic coil having a geometric second longitudinal axis parallel with the first longitudinal axis. The coil has a clear space parallel with the second longitudinal axis. Substantially coaxial with the second longitudinal axis, a carrier rod is rigid in its longitudinal direction relative to the end portion of the bar device and is connected in entraining fashion to the bar device.

Abstract: A method and apparatus for determining the suitability of playground, recreation and sports facilities surfaces as well as determining natural or synthetic surface compactness and hardness. The apparatus includes a transducer module consisting of an impact head and a transducer capable of converting impact forces or g's to electrical signals and an electronic module which detects the electrical signal from the transducer, amplifies the peak value and converts it to a digital, numerical reading. The apparatus is adapted to accept a variety of impact heads, transducers and electronic peripherals depending on specific applications.

Abstract: Apparatus and methods for the in-field measurement of mechanical and physical properties of metallic structures. The apparatus is a Field Indentation Microprobe (FIM) using an indenter that is caused to contact and indent the structure using cyclically applied and released successive increasing loads at the same location. The load and penetration depth data during both cyclic loading and unloading are used to determine the flow properties and fracture toughness of the structure. An X-Y driven testing head supports a load cell which is connected to an indenter holder and the indenter. A displacement transducer is carried by the load cell to measure the depth of penetration of the indenter into the structure, and one or more ultrasonic transducers determine the physical phenomena such as crack size, material pile-up around indentation, and residual stress presence and orientation. A polishing tool is provided to prepare the surface of the structure prior to indentation.

Abstract: A device for testing a sample of foam material and a method for making such a test include compressing the sample repetitively by means of a dropped weight. The weight includes a plunger which moves vertically in a sliding bearing arrangement. The plunger is raised by a solenoid and allowed to drop so as to compress the sample only by a predetermined percentage of its original diameter. The force applied to the sample is monitored during this compression operation and the ratios of forces between the initial force measurement and the force measurement made during subsequent drops provides a quantitative indication of the weakness in the foam cell structure.

Abstract: An apparatus for testing the strength of the sidewalls of hollow tubular members such as for example metal utility poles is disclosed. The present invention provides a self-contained mechanically actuated testing device which is operable to subject a pole to be tested to a concentrated impact force of a predetermined magnitude, the magnitude being selected such that the impacting portion of the tool will penetrate the sidewall if the strength thereof has diminished below an acceptable level.

Abstract: A method of obtaining the peak value of a signal. The signal is sampled at certain intervals of time. The value of the sampled signal is compared subsequent to sampling with a value previously stored in a memory. The higher of the two compared values is stored in the memory for later comparison with a value obtained during a subsequent sampling. The higher of the values stored in the memory is stored in another memory after a maximum signal has been obtained.

Abstract: Apparatus and method for testing structures by impact. The structure is struck by an impactor associated with a force transducer the output of which is related to the force which the transducer experiences on impact and encompasses a frequency range including the lowest frequencies (typically approaching zero frequency, see FIG. 3) which that force contains to any substantial degree. A test spectrum of the force including that full range of frequencies is produced by a Fourier transformer in a form suitable for automatic comparison, and is then so compared with a reference spectrum typical of impact with a reference structure, and a signal is produced indicating fit or lack of fit between the test and reference spectra.

Abstract: The present invention relates to an insulation diagnosis technique for the coil of a generator or the like, especially a strike diagnosis apparatus for diagnosing the good or bad condition of insulation by comparing, directly or after a suitable processing signal, the magnitude of a strike signal applied to the generator's coil with a reference level, or by making a frequency analysis of the strike signal.

Abstract: A method and apparatus for impact testing ice in a laboratory environment simulates in-situ conditions wherein an ice sample is confined triaxially and maintained at a controlled temperature to approximate a semi infinite mass. An impact device impinges on the ice sample so confined.

Abstract: A percussion instrument suitable for use in dental practice for determining the degree of looseness of teeth has a movably seated ram which is accelerated to a defined velocity by an electromagnetic drive means and is subsequently moved toward a test subject (such as a tooth) in free flight. The electromagnetic means also controls return of the ram to a rest position. The ram is comprised of a non-magnetic section and a section of low magnetic retentivity passing through a magnetic coil. Control electronics supplies current pulses to the coil. The velocity of the ram is detected by a measuring and evaluation unit and is maintained at a constant value after a comparison of a rated value with the actual velocity value. The current feed to the coil is discontinued when the rated velocity is reached.

Abstract: An apparatus and method for testing the hardness properties of metallic st materials, wherein electromagnets are employed to replace clamping means. Said apparatus comprises two electromagnets, and a test head which comprises a ball indenter means, a conventional hydraulic hand pump, a pop-off release valve and numerous gauges. A method of testing metallic sheet materials, and specifically armors, is set forth.