Abstract: The present invention provides a free field stress gauge that can operate in a medium with ambient normal stress fields up to 10 kilobars. The invention uses two machined parts, a top annulus cover disc portion and an active bottom disc portion such that the annulus top cover disc covers the active bottom disc portion but allows a solid central sensing column to be exposed to ambient conditions. The disc portions have a dual sealing means to protect the strain gauges therein from fluid ingress. The gauge is suitable for measuring stresses of soil and rock formations as well as concrete, asphalt or other materials in either a static or dynamic regime. The stress gauge is designed for high uni-axial stress measurements, improved frequency response, have low hysteretic induced effects in measurements and be a thinner gauge.

Abstract: A device for measuring the deformation of a structural component comprises a sensor installed at a first end of a hollow bore in the structural component, the sensor having a measuring surface and producing an electrical signal indicative of a deformation in the measuring surface, and a transmission element which passes through the hollow bore. The transmission element has a first end which is supported by the structural component, and a second end which bears upon the measuring surface of the sensor, so that a deformation which occurs in the structural component will be transmitted to the measuring surface by the transmission element.

Abstract: A sensor assembly 1 comprises an optical fibre 4 and a transducer 23 arranged to apply transverse strain to a localised portion 24 of the fibre. Birefringence effects induced by the fibre strain are remotely sensed to obtain a signal representative of the transducer input which in turn is connected to a current sensing coil 34 thereby enabling electric current in a conductor 32 to be remotely sensed. The localised portion 24 of the fibre 4 is stripped to remove an outer jacket and is embedded in a relatively rigid matrix material. Damage to the fibre and the effects of creep are thereby avoided. The resulting sensor is particularly suited to the measurement of high currents in power distribution systems.

Abstract: The sensor which is adapted to e inserted into a bore includes a cylinder-shaped body made of an elastomeric material and four resistive wire strains are uniformly distributed around its circumference. This body of an elastic material can be pressed together by means of tensioning members. This causes a deformation of the body in radial direction, such that the resistive wire strains are pressed against the wall of the bore and contact same in a force-locked manner. At the same time, the sensor is held arrested in the bore. Accordingly, an elongation of the structural member is directly transmitted onto the resistive wire strains, such that errors in the signal transmission are avoided.

Abstract: There is disclosed an apparatus for peeling a semiconductor substrate includes an unit for fixing a reinforcing plate bonded to the semiconductor substrate, a mechanism for pushing the semiconductor substrate bonded to the reinforcing plate in a direction parallel to a bonding surface, a unit for monitoring a stress generated by the semiconductor substrate, and a controller for controlling a driving unit of the pushing mechanism of the semiconductor substrate in accordance with the monitored stress.

Abstract: The present invention relates to a device for detecting, in a machine, the position of contact of two rollers of parallel axes of which at least one is mounted mobile. This device is characterized in that it comprises an elastic member mounted so as to undergo, during contacting of the two rollers, a deformation, limited by a bearing, further to the relative displacement of two elements mobile with respect to each other, and means for measuring this deformation.

Abstract: A fluid temperature measuring device (10) comprises a substrate (12) upon which is deposited a first insulating layer (14). A first metallic layer (16) is sputtered onto the first insulating layer (14), a second insulating layer (18) is deposited on the first metallic layer (16) and a second metallic layer (20) is sputtered onto the second insulating layer (18).The second metallic layer (20) is thin and has a low heat capacity so that it responds quickly to changes in temperature of the fluid. The first metallic layer (16) is thin and is heated by supplying an electric current from an electrical power supply (22) to maintain the first metallic layer (16) at the same temperature as the second metallic layer (20).The second metallic layer (20) is electrically connected to an electrical resistance measuring device (24) which detects temperature changes of the fluid by detecting corresponding changes of the electrical resistance of the second metallic layer (20).

Abstract: A load sensing gasket having a gasket body defining a service opening for fluids and having a load sensor encased in a cavity in the body. The gasket body comprises a first gasket layer providing a first outer gasketing surface and a first inner surface, a second gasket layer providing a second outer gasketing surface and a second inner surface, the inner surfaces together defining the cavity and side walls for defining a perimeter for the cavity. The load sensor includes confronting electrodes and a pressure sensitive electrically resistive material between the electrodes and conductors extending outwardly of the perimeter. A seal between the first and second gasket layers around the load sensor seals the electrodes in the cavity from fluids when the gasket is in use.

Abstract: An accelerometer is shown with improved drop resistance for regulating automotive safety air-bag systems and the like. The device comprises a member of silicon semiconducting material having a central seismic mass mounted on a surrounding support by intervening beams, a pair of beams extending from each of four sides of the mass to the support and the mass being otherwise free of connection to the support to permit movement of the mass along an axis perpendicular to the plane of the support in highly sensitive response to acceleration forces along that axis. Each beam extends from a location near an end of one side of the mass so that the two beams extending from each side of the mass are widely spaced relative to each other to oppose rotational or twisting movement of the mass in response to off-axis acceleration forces to prevent damage to the beams during dropping of the accelerometer to the extent possible consistent with providing the desired sensitivity of response.

Abstract: A method of manufacturing state transducers for mechanical components intended to be subjected to wear, mechanical and/or thermal loads, especially state transducers for tools. The invention is characterized in that electric conductors and, where appropriate, electronic circuits (9) of microscale for measuring wear, mechanical and/or thermal loads are applied on the surface of the component (11), and a protective layer (10) is applied upon at least portions of said circuits (9) and conductors, where said conductors, circuits and said protective layer (10) are applied so as to constitute a unit atomic integrated with the mechanical component (11), which conductors and circuits are intended to be connected to a signal processing or corresponding equipment. The invention also comprises a mechanical component treated according to said method.

Abstract: A flat disc is pressed into a bore provided in a structural member that is under stress. The disc has peripheral teeth that permit to be press fit in the bore and strain gage elements oriented mutually perpendicularly to one another provide inputs to a bridge circuit for monitoring the strain in the member at a preselected location.

Abstract: A force sensor detects adhesion between a subject and a substrate through an adhesive. The sensor is embedded in the adhesive and is formed by two members which are displaceable relative to each other. A readout scheme detects displacement of the two members due to a force and reaction forces acting upon the sensor through the adhesive. Fiber optics may be employed in the readout scheme to provide an indication of displacement of the two members and thereby adhesion of the subject to the substrate.

Abstract: A digital integrator for sensors which takes a time varying current or charge flow signal and converts it into a proportional voltage varying signal. The voltage varying signal is then preferably passed through an active full wave rectification subcircuit to provide an absolute value of the time varying voltage signal. The voltage signal also is analyzed by a zero crossing detector. The absolute value signal is converted into a proportional frequency varying signal which is counted either positively or negatively to produce an integral of the current flow with time. The integrator can be used with sensors such as piezoelectric crystals to indicate force on a real-time basis. The integrator is described as part of an animal hoof force detection system.

Abstract: The autoclave cure process is the representative composite fabrication technique for high quality composite materials for the aerospace and defense industry application. After lay up and vacuum-bagging in a complicated sequence, the several composite material needed in autoclave curing are cured under controlled temperature and pressure. The autoclave curing, in which the total cure process requires at least 4-6 hours, is a very expensive process. Therefore, the determination of an optimal cure process for composite prepregs is very important for guaranteed quality as well as being important economically. Theoretical models cannot be proved because of the lack of experimental methods. The experimenter must run many batches of autoclave curing trial and error at the different curing temperatures and pressures to obtain a sufficient amount of data which can experimentally determine the optimal cure process.

Abstract: This device is adapted for replacable implantation in soft body tissue for the measurement of the mechanical behavior of the soft tissues of the body. The device consists of an hall-effect strain transducer that detects the linear motion of a magnetic core. A barb force transducer uses a barbed probe that is inserted into the soft tissue. The barb force transducer has pressure sensors located within the body of the probe that detect the squeezing of the tissue fibers against the sides of the transducer. The combination of the hall-effect strain transducer and the barb force transducer allows the operator to simultaneously measure the strain and force on a specific soft tissue.

Abstract: A scrap removal system is disclosed for a stamping and forming machine in which strip material is fed in a vertical plane through a tooling assembly having punches and dies therein so that holes are punched in the strip when the punches move through the strip and into the die openings. Such punching operations produce small bits of scrap material commonly referred to as slugs. The die block is mounted against a supporting structure which has passageways extending therethrough in alignment with the die openings so that as the slugs are produced, they are pushed into the passageways and form stacks of aligned slugs. The passageways extend to outlets, past which a slug removing device in the form of an endless belt continuously moves. As the slugs are pushed from the slug outlets, the endless belt carries them laterally and disposes of them at a location beside the tooling assembly. A detecting means is also disclosed which stops the machine in the event of failure of the scrap removal system.

Abstract: A generally oblong mold pressure sensor body containing electrical or mechanical sensing components therewithin actuated by a sensing element or surface on the outside of the body, the sensing element or surface being adapted to engage a mold ejector pin. The sensor body is substantially rectangular in side view and generally peanut shaped in plan view with a relatively narrow waist between forward and rearward lobes. Extending from the forward lobe for engagement with the end of a sensor channel in the mold structure is a tongue of less thickness than the sensor body. The tongue may be removed to change the location of the sensing element relative to the end of the channel in the mold ejector plate. The double lobed sensor body shape provides the stability of a rectangular sensor body in a rectangular channel, however, the lobed body can be slid into and out of a curved blind channel as well as a straight blind channel without disassembly of the ejector plate from the mold.

Abstract: A triple material piezoresistive gage provides multi-component elastic stress or measurements. Thin foils of three piezoresistive materials, e.g. ytterbium, manganin, and constantan, are configured in a nested serpentine rectilinear grid or other grid arrangement and embedded in a medium, preferably normal to the direction of shock wave propagation. The output of the gage is a resistivity change history for each material of the gage. Each resistivity change is independent of the others so that three diagonal components of the elastic stress or strain tensor can be calculated from the resistivity measurements.

Abstract: The measuring-value sensor according to the present invention for the measurement of extensions, for example in concrete or shotcrete, consists of a support member, having an extension stiffness value that is lower than the extension stiffness value of the material diameter displaced by the sensor. Transverse elements are located at either end of the support member, which induce the impact. By combining sufficiently large transverse elements that have a relatively high flexural strength and a support member that has the above-mentioned very low extension stiffness value it is made sure that extensions in the concrete are forced completely and without obstruction upon the support member by means of the transverse elements, so that when measuring the extension of the support member, the extension of the concrete is measured directly and without any distortion. The support member is suitably a hollow profile of aluminum or a plastic material, into which an additional profile, e.g.

Abstract: A method and device for monitoring large structures so as to detect defects, e.g. cracks. An electric current is supplied to a steel structure which is equipped with contact points between which are measured voltage drops caused by the impressed current. A relatively large number of fixed contact points are used all over the area which is to be monitored. The voltage drops are measured between selected pairs of contact points and these voltage drops are compared with corresponding voltage drops that have been measured previously in the same manner when the structure was in an initial condition, preferably without any defects. The monitoring can this be performed by means of robust and simple devices which are relatively impervious to rough environments.

Abstract: A compression strain gauge transducer assembly (10) includes a sensing member (14) that receives a strain gauge transducer (16) within a counterbored hole (26) through a head (18) and shank (20) of the sensing member. An inner pilot end (28) of the sensing member hole receives a pilot (40) of the transducer with flat annular seats (30) and (40) of the hole and the transducer engaged in a manner that provides accurate readings of compression loads in association with the pilot construction. An intermediate portion (46) of the transducer (16) has outer surfaces (48) that define a square cross section with strain gauges (50) mounted on the outer surfaces axially inward from a threaded outer transducer portion (52) received by a threaded outer portion (34) of the sensing member hole (26).

Abstract: A strain gauge transducer (10) disclosed has particular utility when utilized with a bolt (12) to sense loading and has a construction which permits accurate axial alignment, testing before installation, removal for inspection and any necessary repair, and accurate readings that are not substantially affected by bending loading. The transducer (10) includes a body (30) having a web (40) extending between a threaded inner end (32) and an enlarged outer head (34). An annular seat (36) on the head (34) engages a bolt hole surface as the threaded inner end (32) is received by a threaded portion of the bolt hole. At least two strain gauges (46) are utilized with each mounted on one of the parallel web surfaces (42), and wires (50) connected to the strain gauges extend through a wire passage (48) in the enlarged head to permit a signal to be sensed by the strain gauges and fed to suitable instrumentation. In the preferred construction, the web (40) has a thickness in the range of about 0.020 to 0.

Abstract: This strain measuring apparatus shows a device to be press fitted into a hole in a member subject to stress, for the purpose of measuring the strain produced in the member by that stress. The device is a cylindrical shell with a middle portion knurled on its outer surface so that it has an overall diameter slightly greater than the diameter of the hole in which it is to be inserted. A web extends across the interior of the middle portion of the shell perpendicular to its axis. Strain gage elements are attached to the surfaces of the web.

Abstract: A load sensing probe for disposition in a cavity in a back-up member arranged to support a tool at a working station for measuring the strain associated with such working forces applied to the tool comprises a generally cylindrical body member having first and second generally end adjacent regions of substantially equal outside diameter and a third intermediate region of reduced size. A centrally disposed bore extends through the cylindrical member. A first pair of slots extend axially inwardly into the intermediate region and a second pair of slots extend from the second region into the intermediate region and are disposed at a right angle to first pair of slots. A threaded rod having a frusto-conical surface extends through the centrally disposed bore and includes a threaded fastener. This assembly may be utilized to apply outwardly directed forces to the body of the probe to retain it within the cavity of the tool.

Abstract: Described is a novel marker for wire ropes, in the form of a polymer, e.g., polyester film carrying a highly abrasion-resistant impression. This polyester film is wound around a support element in spirally overlapping manner and is worked into a gap between the bundles of strands, at the same twisting angle as the latter.

Abstract: A load measuring apparatus for determining a load affecting a predetermined point of a mechanical system including a solid state member to which the load is directly transmitted and an integrated monolithic sensor, connected with the solid state member, with directional sensitivity to deformation, the sensor producing an electrical signal proportional to the load. The solid state member includes a unilaterally fixed rigid flexional beam having a freely protruding end portion thereof under load stress and a section thereof close to a fixing point which contains in locking contact the sensor which is sensitized in the direction of the maximum inner deformation of the flexional beam.

Abstract: A tie rod load sensor for a die-casting or other machine includes an axially-extending bore formed in the tie rod to receive a strain gauged sensing member. One end of the sensing member is countersunk to receive a ball which concentrates the load when it is forced against the bottom of the bore by a bolt threaded into the opening of the bore. The sensing member includes a narrow central shaft portion upon which a plurality of strain gauges are mounted. The bolt is utilized to pre-load the sensing member such that the strain gauges mounted thereon will measure changes in the tension on the tie rod.

Abstract: A transducer assembly for monitoring stress in flexible sheet material, by responding directly to stress in the sheet and providing an electrical output which is related to the magnitude of biaxial stresses in the sheet. A transducer, for example of a suitable epoxy, is cast as an inclusion through which the stresses from the material are transferred. According to a preferred embodiment, a hole is made in the fabric material and the coating, if present, is removed from adjacent yarns about the edge of the hole to form an annular region to which the transducer then is securely bonded. If a non-yarn material is used then the epoxy is formed about the material per se. One or more electrical strain gages are affixed to the transducer, to directly sense stresses in the material which are transmitted to the transducer. In other embodiments the transducer is an integral part of a piece of sheet material which in turn is spliced into the overall material to be monitored.

Abstract: A load sensing probe for monitoring working forces in compressive elements such as found in presses and other machine tools is disclosed. The probe has an elongate configuration which allows it to be mounted at a point remote from its load sensing end and enables it to be conveniently used with a plurality of similar probes in relatively confined spaces. A split plug includes a slot defining two sensing arms, which arms are pushed outwardly into engagement with an accommodating cavity formed in a back-up member of the machine tool. The probe is sensitive to relative closing movement of the cavity caused by compressive strain in the back-up member.

Abstract: A member of composite material incorporates at least one strain responsive member within a part at which a strain is induced by a load in use. A signal which is a function of a strain detetected by the strain responsive member is communicated to an indicator or monitoring device which registers the applied load causing the strain.In one embodiment a leaf spring for a vehicle comprises upper and lower elements of one or more superimposed strips of pre-impregnated longitudinally extending carbon fibres and an inner element of one or more strips of pre-impregnated glass fibres. During laying up of the strips two strain gauges (13, 14), which may be on or integral with a carrier strip, and their leads (13a, 13b, 14a, 14b) are introduced into the active length of the spring which experiences a bending moment on the application of a load. The gauges are positioned at a pre-determined distance apart which is maintained when the member is cured, as by hot press moulding.

Abstract: A deformograph comprises a sensitive element shaped as a tube of an optically sensitive material and fixed in a borehole by cementing the gap between said tube and walls of the borehole. One end of the tube is tapered off and provided with a specular coating, while the other end thereof has a specular coating with transparent sections. There are also provided a polarized light source furnishing a light signal transmitted through the material of the tube, and a sensing unit designed to pick off from the sensitive element a useful light signal indicative of the changing condition of the earth's crust in a given area.

Abstract: To permit adjustment of the engagement pressure of mutually engaged roller elements, such as bearer rings (1, 3) or rubber blanket cylinders (31-34) against an impression cylinder or plate cylinders (35-38), a blind bore (4) is formed in the respective roller elements in a zone where engagement pressure will result in deformation in a wall of the blind bore, the bore being filled with a fluid such as hydraulic fluid, silicone, or the like, the pressure of which is determined by a pressure transducer such as a piezoelectric element coupled, through an amplifier, to a peak detector which indicates pressure upon axial alignment of the blind bore (4) and the axes of rotation of the respective engaging rollers. A base pressure in the chamber can be adjusted by an outside adjustment screw which, like the transducer, is preferably carried on an external adapter element attached to the respective roller.

Abstract: A major problem in the manufacture of optical fibre cables is the strain to which the fibres are subjected, which strain could damage the fibres. To enable this strain to be monitored, and hence remedial action to be taken, one or more metallic elements are incorporated in the cable, each such element with its insulation being similar in thickness to an optical fibre with its sheath. The electrical resistance of the metallic elements varies very little with temperature, but does vary with strain, so by monitoring resistance, one monitors strain.Although mainly intended for use during manufacture, the method can be used whenever strain monitoring is needed.

Abstract: A cylindrical stress sensor has a case that is long relative to its diameter. The case may be completely imbedded in the body of a host material in which a change of stress is of interest. That portion of the sensor which is imbedded has a rounded end. The rounded end, circular cross section, and relatively large length-to-diameter ratio avoid errors occasioned by stress concentration. A strain transducer of a vibrating wire excited by a magnetic coil is located remote from any imbedded end of the sensor. Changes in strain on the wire alter the frequency of the wire. This change in frequency is picked up by the excitation coil as a signal. A stacked, three-transducer array, with the wire of each transducer at 45.degree. from a neighboring transducer, can detect changes in the magnitudes and directions of the principal stresses, without first establishing the direction of the primary or secondary principal stress.

Abstract: A material tester of minimal thickness is provided. A thin metal plate has in one surface an annular groove, and within the groove the plate thickness is reduced, to an amount less than the groove depth. A flexible diaphragm extends over the central part of the plate and over the groove, and is clamped to the plate by an annular ring overlying the groove. Passages extend in the plate from an edge to a chamber defined by the diaphragm and the central portion of the plate. A supporting structure including a handle is attached to the plate, and conduits extend between passages in the handle and the passages in the plate.

Abstract: A measuring shaft intended to be fixed in a hole is equipped with strain gauges or similar devices for sensing a load. The inner end of the measuring shaft is threaded to engage with threads provided in the bottom of the hole, and the outer end of the measuring shaft is fixed in relation to the hole so that the measuring shaft like a part unseparated from the walls of the hole but nevertheless detachable, accompanies the motions of the said walls.

Abstract: A pressure sensing apparatus for measuring ice pressure forces while embedded in an ice pack is disclosed. The pressure sensing apparatus is thin in comparison to its width and length, having a stiffness similar to the average anticipated stiffness of the embedding material. The apparatus includes a housing having a first and second substantially flat plate connected at their outer edges and sensitive to external ice pressure forces. A thin member is supported within the housing between the first and second plate by a plurality of standoffs or ribs which subjected the member to reverse curvature bending upon the application of external pressures to the first and second plates. Wire resistance strain gauges are attached to the thin member to measure the strain of the member when subjected to the bending. In this manner, the pressure against the sensor can be correlated with the strain measurements resulting on the member.

Abstract: A process for the measurement in vivo of the degree of bone consolidation, characterized in that it consists of implanting directly on the surface of the bone a transmitter with its power supply circuit, the oscillation frequency of the transmitter being capable of varying about a predetermined value during stresses applied to the bone to which the transmitter is secured. Signals emitted by the transmitter are received on a suitable external receiver positioned adjacent the transmitter. The receiver output signals are utilized for various purposes, such as checking, measurement and recording.

Abstract: An embedded stress sensor gage for use in solid fuel rocket motors and the like consisting of a modified bridge circuit containing temperature sensitive resistive elements and a pair of series connected resistors coupled in parallel with the bridge. A comparison of the voltage at the midpoint of the series connected resistors and the output voltage of the bridge and the voltages at the active resistive elements provides information from which it is possible to determine the change in gage element resistance for each temperature and stress condition.

Abstract: A signal classifier system is disclosed that includes an on-line apparatus for monitoring various electrical signal inputs derived from vibration signals without data interruption, and providing an output from each of several levels of classifications. Classification is by a three-level classification algorithm. A first level of classification provides for the independent processing without structural or operational information of each signal input. The output of the first level is stored according to a strain gauge in a spatial file. The second level of classification provides a combination of the output of the spatial file with structural information (such as compressor structural information) and on-line operational information to provide an output indicative of event probabilities which are stored.