Abstract: The displacement sensor of this invention comprises a tube combined with a sonic transmitter and receiver. The tube acts as a waveguide for the sonic waves and a processor determines whether the tube has changed in length or has been constricted which, in either case, changes the pattern of sonic waves traveling from the transmitter to the receiver. In some applications, the transmitter and receiver are at different ends of the tube. In these cases, the attenuation in sound energy reaching the receiver, caused by the tube being squeezed at at least one point, is measured and the amount of cross action area reduction is determined. In other applications, the transmitter and receiver are at the same end of the tube and, in some of these cases, the transmitter and receiver are the same transducer.

Abstract: A device positions the butt end of a firearm. The device functions to assist the user in properly positioning and aiming the firearm. In its broadest context, the present invention includes a cushioning member adapted to be worn approximate the shoulder of the user and a positioning device. This positioning device includes a pressure sensor, a microprocessor and a sounding element. The sounding element gives the user an audible signal when a predetermined amount and distribution of pressure have been applied to the sensor.

Abstract: A self-contained electromagnetic impact sensor includes a frame, a fixed permanent magnet, a fixed coil, and a metallic body elastically mounted for movement within the frame. An impact received by the sensor imparts motion to the metallic body, thereby altering the pattern of magnetic flux extending from the permanent magnet and through the coil. An electrical signal is produced within the coil, which is processed and compared to one or more threshold levels to drive one or more corresponding output triggers.

Abstract: An aftermarket mechanical shock detector for mounting to protected property containing an existing alarm system. The shock detector incorporates a piezoelectric transducer detecting mechanical vibration and generating an electrical vibration signal, and circuitry for comparing the vibration signal to thresholds. The shock detector includes two separately adjustable thresholds. If the vibration signal exceeds either threshold, the shock detector creates an electrical connection between two terminals, thereby triggering a previously-installed alarm circuit to create an alarm.

Abstract: An electrically conductive housing completely envelops an electronic component so as to screen the electronic component from electromagnetic radiation whilst permitting movement of the electronic component relative to the housing when acted upon by an external force. According to a preferred embodiment, the electronic component is a deflection sensor or taut wire sensor for use in an electrical security fence, such that the sensor is completely shielded from the atmospheric effects and stray radiation.

Abstract: A device that mounts on the top of each fence post along a security fence and utilizes an alarming arm which produces an electric alarm signal when moved or displaced. When a multiplicity of the units are mounted on the tops of all of the fence posts along a security fence with the alarming arms pointed outward from the fence line and barrier material is strung between the alarming arms, an extended barrier is created which increases the height of the security fence and produces an alarm when an intruder attempts to climb over the extended barrier and moves the alarming arm(s) or any member of the extended barrier supported by the alarming arm(s), thus moving the alarming arms. An extended barrier may also be installed along the top of walls by installing a plurality of devices spaced at distances approximating the spacing of fence posts along a line of security fence with barrier materials strung between the alarming arm(s).

Abstract: A monitoring sensor for articles susceptible to theft, comprising a sensor element for monitoring a proper contact of the sensor with the article and a connecting cable for connecting the sensor to a monitoring circuit of a theft protection system is proposed. During disconnecting of the proper contact with the article, the sensor makes available a measured variable, the alteration in which can be evaluated by the monitoring circuit as an alarm situation. To enable the sensor to be produced in a flat type of construction and also to be easily connected to curved surfaces of an article to be protected, the sensor and the sensor element are of a flexible design, whereby any alteration in shape during disconnecting of the proper contact between sensor and article results in an alteration in the shape of the contact surface element and in an alteration in the measured variable.

Abstract: A batteryless sensor includes either a micro miniature generator/gear train or a piezoelectric crystal to convert a movement of a door or window to an ersatz V.sub.cc transient power supply to radiate a coded RF signal to a receiver, a distance away. The receiver may monitor a multiplicity of sensors to identify a source of an intrusion.

Abstract: A seismic alarm device for vehicles which is capable of detecting an earthquake while the vehicle is moving and gives the alarm upon occurrence of the earthquake in order to provide the safety such as by stopping the motor vehicle, wherein a plurality of acceleration detectors are mounted on the front and rear of the vehicle or on the left and right sides of the vehicle, output signals generated from these acceleration detectors are fed to a determination circuit, which determination circuit is arranged to measure an amplitude and period of the output signals and to compare phases of the output signals, then to output an alarm signal if the amplitude of the output signals is larger than a predetermined value while their periods are within a predetermined range and no phase difference exists between the output signals of the acceleration detectors, and an alarm circuit gives the alarm when the determination circuit outputs the alarm signal.

Abstract: A retractable sensor assembly for use with an alarm system to prevent theft of valuable products while eliminating the problem of entangled and unsightly sensor cords is disclosed. The retractable sensor allows the user to grasp the product and pull it to a comfortable position. The invention consists of a housing, a retraction means contained in the housing, a sensor having two states, 1) secured when attached to the product and 2) unsecured when detached from the product, a multiconductor cable having a first end connected to the sensor, cooperating with the retraction means and a second end extending out of the housing, where the retraction means urges the sensor to the housing, yet allows the sensor to be pulled from the housing when an external force is exerted on the sensor, while maintaining a continuous electrical path from the first, sensor end of the cable to the second end of the cable.

Abstract: A biosensor feedback device for use in detecting a grip pressure and torque of a hand against a handle of a sporting implement. The device includes a flexible thin film substrate which is conformable to the handle of the sporting implement, and an array of digital pressure sensors disposed on the flexible substrate. The sensors are connected to a signal, such as a buzzer, that indicates detection of pressure or torque exceeding a desired threshold. The array of sensors can be divided into two or more sub-arrays of sensors of different sensitivities, and each of the sub-arrays can be connected to (or disconnected from) the signal as desired. The sensor-beating substrate is secured to the handle of the sporting implement by an elongated, stretchable tubular sheath.

Abstract: A tamper detection sensor comprises an insulating substrate (2) to one side of which are applied electrically isolated strips (4) of an electrically conductive material, an electrically conductive bride member (8) interconnecting the strips (4) and secured to the strips (4) by an electrically conductive adhesive (10), and a layer (12) of electrically non-conductive adhesive applied to the one side of the substrate (2) to encase the conductive strips (4) and the bridge member (8) and by which the sensor can be secured to an item (14) to be protected. On relative movement between the substrate (2) and the layer (12) of non-conductive adhesive, the conductive adhesive (10) is deformed whereby the electrical resistance thereof is altered, this alteration in resistance being detected by an electronic monitor (18) connected to the sensor to provide an indication of the relative movement and therefore of tampering with the sensor.

Abstract: A security device, intended for use as a temporary or permanent vehicle security device, having an intrusion detection device in the form of a pair of electrical contacts supported on a shock amplifying, rigid base and responsive to percussive-type forces for generating a detection signal. At least one of the electrical contacts is supported on a relatively stiff cantilevered arm which will not respond to small movements and vibrations, to thereby avoid generating frequent false alarms. Any contact closure signal from the electrical contacts is processed by a detection circuit which counts multiple contact closures and/or measures total closure time, thus ignoring signals generated from small forces or vibrations, thereby preventing against the source of most false alarms when generating a detection signal.

Abstract: A product, in particular a shoe, apparel, a ball or a fishing lure, incorporating an impact sensing element made from polymeric piezoelectric material. In response to impact, the piezoelectric material generates an electrical signal to a battery-powered light- or sound-emitting unit or to an information display device which is at least partially molded into or contained in the product, thus causing circuitry to energize the light- or sound-emitting device from the battery or to display information on the information display device. In some embodiments involving light-emitting devices such as LEDs, the light is conducted to an outside surface of the product directly through the LED or via one or more optical fibers. A shoe can be provided with numerous light-emitting devices, one or more impact sensing elements, a temperature sensor and appropriate circuitry to process the impact and temperature information.

Abstract: A protective post for guarding gasoline filling station pumps, drive up teller machines, and the like. The post has structural strength for resisting collision by a motor vehicle. It is hinged to its base by a stout spring. The post includes a rubber outer cover and an internal resilient layer, both surrounding a metal core member. Thus, the structure of the post both compresses resiliently and leans in response to contact by a motor vehicle. Both the guarded structure and the vehicle are spared damage by this construction. The warning post has contact actuated visible and audible alarms. Warning or commercial messages in the form of indicia may be located on the exterior surface.

Abstract: A magnetometer vehicle detector for detecting various parameters of traffic on a roadway. A number of sensors, having a compact package, along with connecting cables, may be placed in road way with a small number of standard width sawcuts. Alternatively, sensors may be placed in the roadway within tubes under the external surface of the roadway. The package design of the sensor is such that the sensor can be placed in the sawcut or tube only in a certain way or ways resulting in the most sensitive axis of the sensor being most likely affected by just the traffic or vehicles desired to be detected and measured. The sensor may be a magnetoresistive device having a permalloy magnetic sensing bridge. Multiple sensors may be placed in single or multiple lanes of the roadway for noting the presence of vehicles and measuring traffic parameters such as average speeds, vehicle spacings, and types and numbers of vehicles.

Abstract: An improved vehicle obstacle detector and alarm system (10) consisting of an obstacle detector assembly (12) and an electronic control unit (40). The assembly (12) includes an impact probe (14) that is attached through a flexible rod (16) to the front end (18A) of a housing (18). The housing includes at its rear end (18B) an acoustic transducer cavity (18D) into which is inserted a piezoelectric acoustic transducer (26) that is attached to the first end (20A) of a coaxial cable (20). The second end of the cable (20) is attached to an female connector (22) that interfaces with a male connector (41) on the electronics control unit (40). When the impact probe (14) encounters an obstacle, a series of mechanical oscillations are produced that are mechanically transmitted through the flexible rod (16), the housing (18) and ultimately to the piezoelectric acoustic transducer (26).

Abstract: A bidirectional road traffic sensor include several respective lengths of coaxial piezoelectric cable each having a conductive core, a conductive polymer surrounding the core, a conductive sheath therearound and an electrically non-conductive jacket therearound. The cables are spliced together such that conductive core and conductive sheath of one length of piezoelectric cable is spliced respectively to the conductive sheath and conductive core of another piezoelectric cable. The splices are encapsulated in an electrically non-conductive material so that the spliced lengths of piezoelectric cables respectively constitutes positive, neutral and negative piezoelectric sensors. Pressure changes in the piezoelectric sensors are caused by vehicle passage thereover. In such a manner, electrical pulses are responsively produced by passage of vehicles traversing respective detection zones defined by the sensors and moving in respective particular directions so that such passage of such vehicles may be registered.

Abstract: A latch and alarm device for securing a door activates an alarm of 110-120 decibels for approximately 60 seconds if a force on the door exceeding about 20-30 pounds is detected. The device may be used with either left or right-hinged doors. A panic switch on the device may be used in an emergency to activate the high-output alarm.

Abstract: An aftermarket mechanical shock detector for mounting to protected property containing an existing alarm system. The shock detector incorporates a piezoelectric transducer detecting mechanical vibration and generating an electrical vibration signal, and circuitry for comparing the vibration signal to thresholds. The shock detector includes two separately adjustable thresholds. If the vibration signal exceeds either threshold, the shock detector creates an electrical connection between two terminals, thereby triggering a previously-installed alarm circuit to create an alarm.

Abstract: The presence of yarns of a tentered yarn layer on a textile machine is checked by traversing a feeler transversely across a row of the threads to deflect the yarns. A pressure sensor of the feeler deflects each deflected yarn and generates a signal in response thereto. An optical sensor of the feeler detects each yarn and generates a second signal in response thereto which is compared to the first signal.

Abstract: A collision detection system utilizing a set of primary sensors and a secondary sensor. When a sufficient collision load is applied to the sensors, the sensors output a signal. The primary sensors are constructed to be more sensitive than the secondary sensor. Based on the outputs of the primary and secondary sensors, a control unit detects the collision. Upon detecting the collision, the control unit outputs a collision detection signal which activates a protection device, such as an air bag.

Abstract: An acceleration vector activated system to be used in vehicles in association with brake lights and the acceleration pedal, comprises: (a) acceleration vector sensing apparatus connected to the acceleration pedal, to generate a signal proportional to the acceleration vector of the accelerator pedal; and (b) circuit apparatus, connected to the acceleration vector sensing apparatus and to the vehicle brake lights, the circuit apparatus being capable to analyze the level of the signal generated by the acceleration vector sensing apparatus and to activate the brake lights when the signal is above a predetermined threshold value.

Abstract: Motion and direction sensors for end of train (EOT) telemetry equipment employ a piezoelectric film as the sensing element. The motion sensor has a mechanical design which is optimized for detecting vibration on a railroad car. The electrical circuitry of the motion sensor generates output pulses to the EOT microprocessor which are processed according to an algorithm to make a determination of train motion based on detected vibration levels and rates of occurrence. Also, the EOT microprocessor dynamically adjusts the sensitivity of the motion sensor as a function of detected motion. The direction sensor uses a pendulum aligned with the axis of train motion to stress the piezoelectric film and, like the motion sensor, generates output pulses to the EOT microprocessor. These pulses are processed by a direction sensing algorithm implemented on the EOT microprocessor to determine the direction of train motion.

Abstract: A pin-and-clutch theft-deterrent device that enables instantaneous detection of separation-force tampering with the theft-deterrent device. The device includes a pin in one component and a clutch assembly in a second component for attaching the device to an article to be protected by grasping the pin with the clutch to provide a predetermined retaining force for resisting separation of the components by prying or pulling the components apart; a force-sensitive switch assembly for detecting application to the two components of at least a predetermined threshold separation force applied in opposition to the predetermined retaining force; and a transponder coupled to the switch assembly for responding to an irradiated interrogation signal by radiating an alarm signal when the switch assembly detects application to the two components of at least the predetermined threshold separation force.

Abstract: A unitary flexible housing includes a top wall, having first and second contact plates mounted within a housing alarm cavity positioned between the top wall and the bottom wall, wherein a control housing is arranged to effect actuation of an audible alarm upon the first and second contact plates directed in communication relative to one another upon a vehicle directing the contact plates together. A visual alarm is optionally employed. The housing includes a bottom wall, including projecting nodes for effecting a non-skid bottom wall surface.

Abstract: An electrical shock sensor having a housing containing an electrically conductive plug member having a conical configuration. An electrically conductive collar member is coaxially positioned over the conical configuration. An electrically conductive spring is connected between the annular collar and a stationary part within the housing. A first electrical connection is made to the plug member and a second electrical connection is made to reach the conductive spring. The shock sensor is included within a burglar alarm including an energy source and an alarm means. Natural vibrations will cause the spring to oscillate or vibrate without moving the collar. However, impact onto the shock sensor will cause the spring to sufficiently jar thereby displacing the annular collar from its position with respect to the conical surface.

Abstract: A vehicle obstacle detector (10) that is designed to alert the driver of a motor vehicle that the vehicle has encountered an obstacle. The detector (10) consists of an obstacle detector assembly (12) that includes a front probe (14) having a cavity (14b) that houses a piezoelectric element 14c. The probe (14) is attached to a flexible housing (16) that can be attached by means of a clamp (20) to the curb side of a vehicle or alternatively, the detector can be mounted to a wall (60) of a structure. The probe (14) produces electrical oscillations when the probe touches or scrapes against an obstacle. The oscillations are applied to an electronics control unit (30) that subsequently produces an alarm signal that energizes a visual and/or an audio alarm. The alarm may be located in the cab of a vehicle or on the wall when a wall mounted assembly (12) is employed.

Abstract: An automobile theft sensor has a piezo-electric element adhered at one side to a base member and which generates a voltage in response to vibration of the automobile body, a weight adhered to the opposite side of the piezo-electric element, a silicon rubber coating covering at least a portion of the surface of the piezo-electric element and weight, a low pass filter for receiving the output voltage of the piezo-electric element and for providing an ultra low frequency signal within the range of 1-5 Hz produced by the above mentioned piezo-electric element; and a band pass filter for receiving the output voltage of the piezo-electric element and for providing a low frequency bandpass signal centered on the 30-50 Hz produced by the above mentioned piezo-electric element in response to vibration of the above mentioned automobile body. When either of the filter outputs exceeds a predetermined level it is judged that theft or tampering is occurring.

Abstract: A vehicle collision detecting apparatus includes an acceleration sensor detecting acceleration of a motorcar, a frequency filter extracting a signal in a predetermined frequency band from the acceleration signal, and a detector for detecting a collision in accordance with the extracted signal. The detector supplies a trigger pulse to an airbag driver circuit.

Abstract: A sound-giving tread mat has a bag-like tread mat, a foam rubber sheet interposed in the tread mat, one or more buzzers partly adhered on the inner surface of the lower layer of the tread mat, and a sound-giving electric unit to give out sounds. The buzzer(s) is electrically connected with the sound-giving unit placed on a corner surface of the tread mat or somewhere inside a door in a house. When the tread mat is treaded on with a shoe of a visitor, the buzzer(s) can be vibrated by the compressed air in the tread mat to give out an electric signal, and then the sound-giving electric unit amplifies the electric signal coming from the buzzer(s) and gives out sounds.

Abstract: A piezoelectric resilient arm contacts a projected object and establishes a reference relative to sensitivity means and differential detector means including feedback coupled amplifier means which operates in cooperation with a balanced square wave generator means for producing a switched output upon detecting motion. An alarm signal is produced which has a duration related to the rate of change of movement of the piezoelectric resilient arm. Programmable delay means appropriately enables an annunciator and/or wireless communication link to a system controller.

Abstract: A treadle switch assembly for installation in a roadway bed for use in sensing vehicular traffic flow thereover is disclosed. The assembly includes at least one elongated treadle constructed of a compressible, resilient material which contains a hollow passageway throughout its length. Also included is a photocell emitter and a photocell collector, which elements are connected to opposite ends of the treadle and inserted into opposite ends of the passageway. When the treadle is compressed by a vehicle tire, the passageway is mashed closed to interrupt the radiation beam from the emitter to the collector, whereby the collector generates a signal indicative of the passage of the vehicle tire thereover, which signal may be used to operate a suitable counter or signal device as desired.

Abstract: An industrial truck designed, for example, as a counterweight fork lift truck has a lifting stand 2, which is pivotable around a tilting axis N situated crosswise to the vehicular longitudinal axis in the front area of the vehicle in a lifting stand support. The counterweight fork lift truck is also provided with a monitoring unit for detecting and indicating the loading state, which has at least one measuring device located in the lifting stand support. The measuring device designed, for example, as a strain gauge 12, 13 picks up the vertical bearing forces and the horizontal ones parallel to the vehicular longitudinal axis, F.sub.V and F.sub.H. The measuring device is connected with a data storage unit 13, which is connected to a loading state indicator 14. Both static and dynamic loads on the fork lift truck can be indicated.

Abstract: A rockbolt monitor monitors increased loadings on a rockbolt in underground mines. The monitor includes a rockbolt plate fitted on the rockbolt to engage the surface of the rock, a stack of belleville washers on the end of the rockbolt outside the rockbolt plate and a spring seat plate outside the belleville washers. When a nut is fitted onto the rockbolt and torqued, the belleville washers will compress to provide the desired force urging the rockbolt plate against the surface of the rock. This spring arrangement allows relative movement of the rockbolt plate on the rockbolt in response to ground movement, such as caused by blasting. The load indicator itself includes a threaded sleeve screwed into a threaded bore in the spring seat plate. A spring loaded piston rides in the sleeve. It is biased into engagement with the rockbolt plate.

Abstract: An indicating device for repeatedly indicating variation in the load on a part such as a polish rod of a pump is disclosed. The indicating device includes an indicator for providing an indication when current flows through the indicator, a switch for moving between an opened and a closed position and for permitting current to flow through the indicator when the switch is in one of the open and closed positions, and reciprocating moving means for reciprocally moving in response to reciprocating movement of the part and for moving the switch to the one of the open and closed positions once during each cycle of the reciprocating movement of the reciprocating moving means. The indicator thus provides the indication once during each cycle of the reciprocating movement of the part and thus repeatedly indicates reciprocating movement of the part.

Abstract: An automobile theft alarm apparatus for detecting the variation of the inclination angle of the automobile includes: a sensor of a bridge configuration mounted in the automobile for sensing the angle of inclination of the automobile; a differential amplifier for amplifying the output of the sensor; an offset compensating circuit which produces a reference voltage for the differential amplifier by comparing the output of the differential amplifier with a constant value and by then integrating the differential output; an alarm device for issuing an alarm when the output of the differential amplifier exceeds a predetermined value; and a switching device for increasing a time constant for making the total integration time constant for the offset compensating circuit larger than the time constant of the integrating elements thereof by intermittently supplying the output of the differential amplifier to the offset compensating circuit.

Abstract: A torque wrench has a battery-powered sensing circuit which produces a torque signal proportional to the level of the torque applied. A reference signal corresponding to a predetermined torque level is subtracted from the torque signal to produce a difference signal which is, in turn, compared with a compensation signal which is proportional to the rate of change of the torque signal and is produced by differentiating the torque signal. When the value of the difference signal exceeds the value of the compensation signal, an indicator is triggered to produce a tactile indication, the indication being produced prior to the time that the torque signal reaches the reference level by a predetermined time period.

Abstract: A security device for deterring theft of articles of merchandise displayed for customer handling and demonstration. A cable is attached to an article and is extendable under tension from a storage reel attached to a store fixture. A switch adjacent to the reel is held in one of two operative positions by the cable stretching across an actuator arm of the switch. If the cable is severed or cut, as by a thief intending to steal the article, the storage reel retracts the cable past the actuator arm causing the switch to change to the other position and actuate an alarm.

Abstract: Safety device which can be activated, in particular, by a moving body such as a person or an object, in particular a safety gate, comprising a post (2) carrying, at a distance from the ground, a crossbar (4), a first connector for joining the bar to the post and a second connector (3) for joining the post to the ground, at least one of the connectors comprising a holding device (14, 15) capable of releasing the bar when it is subjected to a force caused by the passage or the movement of the said body, and an electrical connection (15) stressed when the bar is released.

Abstract: A monitoring system for monitoring a vending machine at a remote location, the monitoring system including an inventory sensing system for providing a continuous update of the inventory in the vending machine, an alarm system to signal when the vending machine is being damaged or the systems in the vending machine are in need of attention, a communication system, and a credit card verification system. The vending machine is coupled to a central computer system which monitors all the systems in the vending machine. The communication system includes a credit card verification system, a two-way communication capability, a display screen, and a printer.

Abstract: Devices and methodology are provided for measuring mechanical strain in a structural member. The devices and methodology utilize a material which undergoes a change in phase when strained so that measurement of the phase change indicates strain. Preferably the phase change material is a transformation induced plasticity steel alloy. The elements may be configured as gauges secured to a structural member, but also the elements may perform as part of the structure. A plurality of elements may be organized into a monitoring system, either passive or active, for a complex structure.

Abstract: A fail safe auto theft alarm includes a sound maker coupled to a complex switch includes a plurality of switches in series. One switch can deactivate the alarm. An activation switch is coupled to the shock absorber so that the alarm is activated only by motion up and down of the auto such as occurs during driving. A delay can prevent activation by single impacts. A pulser can generate an alarm unique to stolen autos. The switch is activated during theft by a rod coupled to the rear shock, then up into the trunk to activate the switch. The switch deactivation switch may be hidden on the dash panel of the auto.

Abstract: A safety cushion provides a mattress for cushioning the fall of a child, and an alarm for alerting an adult of such a fall; and specifically includes an air mattress and an alarm in circuit connection with a pressure-responsive switch disposed within the air mattress.

Abstract: A method for predicting and controlling the strength development of concrete includes placing test concrete having the same composition as the subject concrete in a vessel which may be temperature regulated. The temperature inside the vessel is measured and recorded in a data memory and a data processor. The data is transmitted either in real time or from the data memory and data processor by way of a data transmission line to a temperature regulator for regulating the temperature inside the vessel. The temperature history of the test concrete can then simulate the temperature history of the reference concrete. The strength of the test concrete is measured at different times and the strength data of the test concrete is collected, processed and interpreted. A vessel for receiving the test concrete, a temperature regulator, a temperature controlling unit, a data recorder, a data transmitter and a computer are included.

Abstract: A stability monitoring and alarm system for a motor vehicle (e.g., a truck or a tractor trailer) provides an early warning to the driver of unsafe or potentially unsafe conditions. Front wheel desynchronization and rear load distribution are each monitored, and an alarm is generated if either the front wheels become desynchronized or the load is unevenly distributed in the rear of the vehicle. Various filtering and averaging techniques avoid false alarms and increase reliability and sensitivity. Thresholding of the front wheel desynchronization comparison is based on a model which takes turning lateral G force for particular speeds into account so that an alarm based on front wheel descynchronization is not generated because of taking turns too rapidly. Rather, such alarm is generated by monitoring shifting rear load distribution --a better and more accurate measure of vehicle stability. The resulting indications provided by an easy to read user interface warn the driver of a variety of conditions (e.g.

Abstract: The present invention relates to a method and apparatus for detecting and for recognizing impacts by measuring changes in impedance. The device comprises a sensor (6) and an external electronic system (10) which permanently monitors the impedance of the sensor. After a learning period, the electronic system records the impedance of the apparatus at rest, after which, whenever the sensor is subjected to an external action (9), its impedance varies at a certain rate of change, thereby enabling the electronic system to detect the derivative of the rate of change of the impedance, or in a different application to detect the pure change in impedance, and transmit a signal to a user (16).

Abstract: Connector plates are positioned at selected truss joints by representing each wood member of the truss as a corresponding two-dimensional polygon. Each side of the polygon is defined by a corresponding member vector having starting and ending points relative to a predetermined reference point. A particular member vector is selected as a boundary vector for each joint boundary, beyond which the connector plate cannot extend. The connector plate is represented as a rectangle of predetermined dimensions corresponding to the actual plate dimensions. Each side of the rectangle is defined by a corresponding plate vector having starting and ending points relative to the reference point. The rectangle is moved within the prescribed joint boundaries by eliminating the points of intersection between the boundary vectors and the plate vectors.

Abstract: The lifetime NF (number of cycles to failure) of a metallic structure such as a soldered joint or the like is determined by three simple, rapid tests. The first is to determine creep displacement rate vs. load (stress). Next, from the same data, the slope of the matrix creep displacement vs. load (stress) curve is determined. A third test is to obtain load (stress) relaxation over a short period of time from a load (stress) in the matrix creep displacement region. The matrix creep displacement per cycle (CPS) is then derived by plotting matrix creep displacement rate vs. time and integrating the area under this curve.

Abstract: Net section parameters of connector plates at selected truss joints are determined by representing each wood member as a corresponding two-dimensional polygon and the connector plate as a rectangle of predetermined dimensions corresponding to the actual dimensions of the plate. When the plate is positioned at a particular truss joint, the area of intersection between the plate rectangle and the polygon defines an intersection polygon. The intersection polygon is rotated and the Cartesian coordinate system of the intersection polygon is redefined so that a first axis thereof is aligned with a central major axis extending along a geometric center of a major surface of the particular wood member.