At least one dynamic condition of a pneumatic tire of a vehicle is determined by measuring the rotational angular position of the tire and/or a wheel or wheel carrier the tire is mounted on. The position measurement is preferably combined with transponder measurements of tire pressure and/or temperature, and the measurement information is transmitted from a tire or wheel antenna to a receiver with one or more antennas on the vehicle. The measurements can be combined with a tire pressure regulating device. The rotational angular position is preferably measured by monitoring fluctuations in coupling of RF power between the transmitting and the receiving antennas. In a preferred embodiment, transponders and antennas are disposed in both the tire and the wheel or wheel carrier for the purpose of monitoring the rotational angular position of a tire relative to its wheel or wheel carrier, thereby indicating torsional effects on the tire. Preferably, the tire antenna in the preferred embodiment is mounted inside the tire near the outer circumference of the tire.

The present invention relates to a system for and a method of measuring a dynamic condition of a pneumatic tire and, more particularly to a system for and a method of determining at least one dynamic condition of a pneumatic tire by measuring the rotational angular position of the tire and/or a wheel or wheel carrier the tire is mounted on.
The present invention relates to monitoring of conditions of any rotary element, but is particularly concerned with the monitoring of conditions of wheels and pneumatic tires mounted on wheels. As a rotary element, a tire""s angular position, rotational (angular) velocity and acceleration, rate of change of acceleration, and revolution count are important in determining such things as vehicle and/or tire instantaneous position, speed, mileage, acceleration and braking, slip/skid, and are also factors in the wear of the tire. Certain of these elements are utilized in control of vehicle braking systems, such as automotive and aircraft ABS systems (anti-lock braking system). Existing monitoring systems generally assume the approximation that the tire/wheel assembly is rigid in the tangential direction (tangential to the direction of rotation, e.g., forward or backward relative to a rolling tire). The present invention moves beyond this rigid approximation in order to monitor other wheel and/or tire operating characteristics, such as for example, torque on the tire.
In addition to rotational/angular characteristics, other important characteristics to be monitored in a pneumatic tire are pneumatic pressure and temperature. Pressure (pneumatic pressure) is well known as a critical factor in pneumatic tire operation, most importantly if there is a loss of sufficient pressure to safely operate the tire, e.g., a xe2x80x9cflat tirexe2x80x9d. The (pneumatic) temperature is generally of secondary importance. Although it can be used to indicate an average temperature of the tire and wheel surrounding the pneumatic cavity, temperature is mostly used to normalize a pressure measured in a hot tire to a xe2x80x9ccold pressurexe2x80x9d value, i.e., the pressure as it would be in a xe2x80x9ccoldxe2x80x9d tire.
A great deal of prior art is devoted to apparatus and methods for measuring and monitoring rotary element and pneumatic conditions, particularly as they relate to pneumatic tire conditions.
THE ASSIGNEE""S ONGOING DEVELOPMENT EFFORTS
For a century, the Goodyear Tire and Rubber Company of Akron Ohio, assignee of the present invention, has been the uncontested industry leader in tire product technology. For example, as early as 1892, a puncture-resistant tire was patented. In 1934, a year recognized as the beginning of the run-flat era, Goodyear introduced the Lifeguard (tm) safety tube, a fabric tube within the tire, used commercially by automakers and on trucks. In 1993, Goodyear""s Eagle GS-C EMT (Extended Mobility Technology) Tire won the Discover Award for Automotive Technological Innovation. In 1996, the Goodyear Eagle F1 run-flat tire was chosen as standard equipment on the 1997 Chevrolet C-5 Corvette.
Other examples of the strides Goodyear has taken in the advancement of tire and related technologies include, but are not limited to, the following patented inventions:
Commonly-owned U.S. Pat. No. 3,665,387 (Enabnit; 1972), entitled SIGNALLING SYSTEM FOR LOW TIRE CONDITION ON A VEHICLE, incorporated in its entirety by reference herein, discloses a low tire pressure warning system adaptable for any number of wheels of a vehicle and providing dashboard indications of system operation and low pressure conditions while the vehicle is in motion.
Commonly-owned U.S. Pat. No. 3,831,161 (Enabnit; 1974), entitled FAIL-SAFE MONITORING APPARATUS, incorporated in its entirety by reference herein, discloses monitoring vehicle tire pressure wherein the operator is warned of an abnormal or unsafe condition of one or more of the tires.
Commonly-owned U.S. Pat. No. 3,872,424 (Enabnit; 1975), entitled APPARATUS AND METHOD FOR TRANSMITTING AUXILIARY SIGNALS ON EXISTING VEHICLE WIRING, incorporated in its entirety by reference herein, discloses communicating with low tire pressure monitoring circuits using power pulses carried on existing vehicle wiring (e.g., the turn signal circuits).
Commonly-owned U.S. Pat. No. 4,052,696 (Enabnit; 1977), entitled TIRE CONDITION MONITOR, incorporated in its entirety by reference herein, discloses a tire condition sensing circuit that includes a ferrite element that changes from a ferromagnetic to a non-ferromagnetic state in response to a temperature increase above the material Curie point.
Commonly-owned U.S. Pat. No. 4,099,157 (Enabnit; 1978), entitled SINGLE WIRE POWER/SIGNAL SYSTEM FOR VEHICLE AUXILIARY DEVICES, incorporated in its entirety by reference herein, discloses providing both power to and receiving detection signals from a remotely located condition monitoring device using a single wire with ground return through the vehicle frame.
Commonly-owned U.S. Pat. No. 4,911,217 (Dunn, et. al.; 1990), entitled INTEGRATED CIRCUIT TRANSPONDER IN A PNEUMATIC TIRE FOR TIRE IDENTIFICATION, incorporated in its entirety by reference herein, discloses an RF transponder in a pneumatic tire. FIG. 1a of this patent illustrates a prior-art identification system (xe2x80x9creaderxe2x80x9d) that can be used to interrogate and power the transponder within the tire. The identification system includes a portable hand-held module having within it an exciter and associated circuitry for indicating to a user the numerical identification of the tire/transponder in response to an interrogation signal.
Commonly-owned U.S. Pat. No. 5,181,975 (Pollack, et. al.; 1993), entitled INTEGRATED CIRCUIT TRANSPONDER WITH COIL ANTENNA IN A PNEUMATIC TIRE FOR USE IN TIRE IDENTIFICATION, incorporated in its entirety by reference herein, discloses a pneumatic tire having an integrated circuit (IC) transponder and pressure transducer. As described in this patent, in a tire that has already been manufactured, the transponder may be attached to an inner surface of the tire by means of a tire patch or other similar material or device.
Commonly-owned U.S. Pat. No. 5,218,861 (Brown, et al.; 1993), entitled PNEUMATIC TIRE HAVING AN INTEGRATED CIRCUIT TRANSPONDER AND PRESSURE TRANSDUCER, incorporated in its entirety by reference herein, discloses a pneumatic tire having an integrated circuit (IC) transponder and pressure transducer mounted within the pneumatic tire. Upon interrogation (polling) by an external RF signal provided by a xe2x80x9creaderxe2x80x9d, the transponder transmits tire identification and tire pressure data in digitally-coded form. The transponder is xe2x80x9cpassivexe2x80x9d in that it is not self-powered, but rather obtains its operating power from the externally-provided RF signal.
The commonly-owned U.S. Patents referenced immediately hereinabove are indicative of the long-standing, far-reaching and ongoing efforts being made by the Goodyear Tire and Rubber Company in advancing tire product technology, particularly in the area of monitoring tire operating conditions.
Dynamic Conditions
Dynamic conditions such as position and angular velocity of a rotary element are readily measured.
U.S. Pat. No. 3,831,570, incorporated in its entirety by reference herein, discloses measuring a crankshaft""s rotary position using a magnetic pickup coil, a rotating toothed wheel, and a permanent magnet. The toothed wheel has a number of teeth corresponding to the number of spark plugs.
U.S. Pat. No. 3,832,640, incorporated in its entirety by reference herein, discloses determining a large number of angular relationships (rotary positions) in a rotating element such as a crankshaft.
Straightforward tire revolution counters are well known, and are disclosed for example in U.S. Pat. Nos. 4,842,486 and 5,524,034, both of which are incorporated in their entirety by reference herein.
U.S. Pat. No. 5,218,862, incorporated in its entirety by reference herein, discloses a tire pressure monitor comprising wheel speed sensors located at the vehicle""s wheels to convey wheel speed information to an electronic controller. This patent notes that the wheel speed discrepancy between one tire to the others indicates the relative tire pressure, but that discrepancy may also be indicative of the vehicle turning, accelerating or decelerating, going up or down steep grades, or of one wheel slipping, or of a cross wind bearing on the vehicle.
U.S. Pat. No. 5,274,355, incorporated in its entirety by reference herein, discloses a system for monitoring pressure and temperature of rotating pneumatic tires. An elastic diaphragm is embedded in or bonded to the sidewall of the tire. Tire pressure changes cause measurable expansion and contraction of the diaphragm surface. The diaphragm comprises a pair of reflective stripes spaced apart from one another at a fixed distance to define a reference dimension, and another pair of reflective stripes which move relative to one another as the diaphragm expands or contracts in relation to the tire inflation pressure. The time interval between pulses associated with the reflective stripes, as sensed by photodetectors affixed to the vehicle indicates individual tire speed. The background infrared radiation naturally emitted from the tire indicates tire temperature.
U.S. Pat. No. 5,345,217, incorporated in its entirety by reference herein, discloses measuring wheel speed of a motor vehicle with a multi-tooth pulse generator on each wheel (as is used on electronic Anti-Lock Braking Systems) to produce a series of pulses spaced apart by equal increments of angular rotation of each wheel. The speed of each wheel is compared to the others, to determine if, and to what extent, a tire is deflated.
U.S. Pat. No. 5,569,848, incorporated in its entirety by reference herein, discloses a system for monitoring tire pressure, comprising toothed ring sensors affixed to each wheel assembly, a sensor operatively associated with each respective toothed ring and producing signals that are a measure of the rotational velocity of the wheels, and a computer receiving signals from the sensors. The computer monitors the wheel speed sensors during vehicle operation, calculating and indicating vehicle speed, distance traveled by the vehicle and low tire pressure.
U.S. Pat. No. 5,721,528, incorporated in its entirety by reference herein, discloses a low tire pressure warning system utilizing angular displacement sensors at each wheel. The system utilizes wheel displacement sensors already in place on vehicles that include ABS systems. Certain vehicle operating conditions, such as excessive or very low speeds, braking, and turns, are determined from the sensor outputs.
U.S. Pat. No. 3,588,814, incorporated in its entirety by reference herein, discloses an electric tire inflation indicator which determines the inflated condition of a tire by monitoring the rotational travel speed of the tire""s respective wheel, by means of a stationary reed switch and a magnet rotating with the wheel.
U.S. Pat. No. 5,749,984, incorporated in its entirety by reference herein, discloses a tire monitoring system and method utilizing a sensor in the tire to detect tire sidewall deflection and thereby determine tire pressure, tire speed and the number of tire revolutions.
Static Conditions
In addition to the aforementioned dynamic conditions (e.g., position, rotational velocity and acceleration), static conditions are also associated with rotating elements such as pneumatic tiresxe2x80x94for example, pressure and temperature. Failure to correct quickly for improper tire pressure may result in excessive tire wear, blowouts, poor gasoline mileage and steering difficulties. An automatic tire deflation warning system is especially critical for xe2x80x9crun flatxe2x80x9d tires, where the deflated condition is barely detectable by the driver himself. Sensors for static parameters are typically located within the rotating tire, and associated circuitry can transmit data indicative of a sensed condition to an on-board receiver within the vehicle.
Transponder Systems for Pneumatic Tires
A xe2x80x9ctransponderxe2x80x9d is an electronic device capable of both receiving and transmitting radio frequency (RF) signals. Transponder systems, typically including a plurality of transponders and a single interrogator are well known and disclosed, for example, in U.S. Pat. No. 5,339,073, incorporated in its entirety by reference herein.
It is known to put transponders (and associated sensors) in pneumatic tires of motor vehicles. These transponders transmit a RF wave, with or without variable data (e.g., tire pressure, temperature, position) and/or fixed data (e.g., tire ID) to outside the tire, and receive RF signals, with or without data, from outside the tire. A separate transponder is typically associated with each tire of a motor vehicle to monitor and transmit tire-related data. Typically, an xe2x80x9cinterrogatorxe2x80x9d having both transmitting and receiving capabilities is used to communicate with the transponders. The interrogator may be xe2x80x9chand-heldxe2x80x9d, or mounted xe2x80x9con-boardxe2x80x9d the vehicle, or positioned along or in a roadway (e.g., xe2x80x9cdrive-overxe2x80x9d, or xe2x80x9cdrive by xe2x80x9d).
xe2x80x9cActivexe2x80x9d transponders have their own power supply (e.g., a battery). They transmit signals, and are typically also capable of receiving signals to control their functionality.
xe2x80x9cPassivexe2x80x9d transponders are powered by the energy of an incoming RF signal, such as from an interrogator. Passive transponders fall into two general categories, those having only passive circuitry, and those having some active circuitry. In the main, transponders which are passive transponders having some active circuitry are discussed herein.
U.S. Pat. No. 5,612,671, incorporated in its entirety by reference herein, discloses a low tire pressure warning system having a pressure sensor and radio transmitter in each wheel, and a vehicle-mounted receiver including a microprocessor.
U.S. Pat. No. 4,609,905, incorporated in its entirety by reference herein, discloses a passive transponder having only passive circuitry. An RF transmitter in the vehicle interrogates the transponder, which reflects a predetermined harmonic of the RF signal back to a receiver as a function of the state of an associated pressure switch.
U.S. Pat. No. 4,067,235, incorporated in its entirety by reference herein, discloses a passive transponder with a tire pressure sensor. Electromagnetic radiation generated by a power transmitter is received by a receiving antenna comprising an inductor and a capacitor in the tire pressure sensor. This radiation is converted by a rectifier-filter to electricity to power active components (oscillator, buffer amplifier, transmitter) of the transponder.
U.S. Pat. No. 4,724,427, incorporated in its entirety by reference herein, discloses a passive transponder that receives a carrier signal from an interrogator. The carrier signal is rectified by a rectifying circuit connected across the transponder""s antenna coil to generate electricity to power the transponder. Data is encoded and mixed with the carrier signal in a balanced modulator circuit. The output of the balanced modulator circuit is transmitted back to the interrogator unit.
U.S. Pat. No. 4,703,650, incorporated in its entirety by reference herein, discloses a circuit suitable for one of many methods of coding for transmission the values of variables measured in a tire, and a device for monitoring tires employing such a circuit. An astable multivibrator transforms the measurement of the variable in question, for instance pressure and temperature, into a time measurement. The astable multivibrator delivers a pulse signal whose pulse width is a function of the temperature and the cyclic ratio of which is a function of the pressure. The signal is suitably transmitted from the tire to the vehicle by, for example, inductive coupling.
U.S. Pat. No. 4,730,188, incorporated in its entirety by reference herein, discloses a passive transponder excited by an inductive coupling from an interrogator. The transponder responds to the interrogator via the inductive coupling with a signal constituting a stream of data. The transponder comprises an induction coil serving as its antenna, and a full wave rectifier bridge and smoothing capacitor connected across the antenna to provide DC voltage (power) to active circuitry within the transponder.
U.S. Pat. No. 5,969,239, incorporated in its entirety by reference herein, discloses some forms of antennas for electromagnetically coupling moving transponders in tires to stationary antennas on the vehicle. The patent concerns replacing an annular coil type of rotating antenna with a smaller antenna integrated with the measurement sensor (transponder) in one small box firmly attached to the wheel, plus a closed circular strip-iron coupling ring attached to and coaxial with the wheel. The rotating antenna, stationary antenna and coupling ring are positioned so that electric current is induced in the coupling ring by magnetic flow in either of the antennas and vice versa. Alternate embodiments are mentioned which consider using the xe2x80x9cmetallic environmentxe2x80x9d in place of the ring of strip iron, for example the wheel itself, or at least one of the metallic beads of the tire. The frequency of transmission is from 30 to 100 kilohertz.
U.S. Pat. No. 5,824,891, incorporated in its entirety by reference herein, discloses xe2x80x9ca transmitting circuit . . . mounted on a frame member. The transmitting circuit includes a transmitting coil and generates electrical energy . . . .xe2x80x9d A xe2x80x9creceiving is inductively coupled to the transmitting circuit. The receiving circuit includes a sensor for generating a data corresponding to a physical characteristic of the vehicle wheel and a wireless communication circuit for receiving the electrical energy from the transmitting coil to remotely power the receiving circuit and for transferring the data signal from the receiving circuit to the transmitting circuitxe2x80x9d.
U.S. Pat. No. 4,911,217, incorporated in its entirety by reference herein, discloses an RF transponder in a pneumatic tire. FIG. 1a illustrates a prior-art identification system (xe2x80x9creaderxe2x80x9d) that can be used to interrogate and power the transponder within the tire. A portable hand-held module has within it an exciter and circuitry for indicating the numerical identification of the tire/transponder.
U.S. Pat. Nos. 5,181,975 and 5,218,861, incorporated in their entirety by reference herein, disclose a pneumatic tire having an integrated circuit passive transponder located within the structure of the tire for use in tire identification and pressure data transmission. The interrogation signal is rectified by circuitry in the transponder, which then utilizes the rectified signal as its source of electrical power for use in its transmission of digitally encoded signals.
U.S. Pat. No. 4,220,907, incorporated in its entirety by reference herein, discloses a low tire pressure alarm system for vehicles. Each wheel is provided with a transmitter, and there is a common receiver comprising a suitable antenna such as a ferrite loopstick.
U.S. Pat. No. 4,319,220, incorporated in its entirety by reference herein, discloses a system for monitoring tire pressure, comprising wheel units in the tires and a common receiver. Each wheel unit has an antenna comprising a continuous wire loop disposed against the inner periphery of the tire for transmitting signals and for receiving power. Multiple antennas may be provided for the receiver, and may be in the form of ferrite loopsticks.
U.S. Pat. No. 5,319,354, incorporated in its entirety by reference herein, discloses an antenna structure for communicating with an electronic tag (transponder) implanted in a pneumatic tire. This patent recognizes that the orientation of the transponder with respect to the antenna communicating with the transponder can adversely affect coupling between the interrogation antenna and the transponder antenna. A construction of an interrogation antenna is described so that, regardless of the position of the transponder in the pneumatic tire, a position of which is unknown, the coupling is always of the same quality.
The following U.S. Pat. Nos. are also cited as being of interest: 3,835,451, 4,755,345, 5,095,309, 5,235,326, 5,537,867, 5,559,507, 5,594,448, 5,731,754, 5,790,016, 5,790,016, 5,824,891, and 5,826,207, all of which are incorporated in their entirety by reference herein.
International Publication No. WO 99/52722 (Oct. 21, 1999), incorporated in its entirety by reference herein, discloses a method and apparatus for sensing tire pressure in a vehicle wheel which is wireless. It employs xe2x80x9cknownxe2x80x9d pressure and temperature sensors, xe2x80x9cknownxe2x80x9d revolution detectors (e.g., ABS), and xe2x80x9cknownxe2x80x9d controllers. A transducer, the sensors, a power source (e.g., battery), and a transmitter are mounted on the wheel rim, interior to the tire. The transducer measures a pneumatic pressure and/or temperature and/or wheel speed that is converted into a wireless data signal by the transmitter. A receiver coil [antenna] is connected to a portion of the vehicle, such as a wheel well member, preferably within three tenths of a meter of the transducer/transmitter coil. Another coil connected to the vehicle may be tuned to receive wheel speed signals from the xe2x80x9cknown typexe2x80x9d of wheel speed sensor, and these signals are conditioned by the receiver and passed to the controller along with the pressure and temperature signal. The pressure/temperature signal and the wheel speed signal may be distinguished by various known means such as by frequency or modulation design, or a separate receiver can be utilized.
Tire Pressure Regulation
In addition to sensing, if not measuring/monitoring, pneumatic tire pressure, a variety of systems have been developed to regulate, adjust and/or replenish the pneumatic medium (air) in a tire.
U.S. Pat. No. 5,505,080, incorporated in its entirety by reference herein, discloses a tire pressure management system including a tire condition monitor connected to the tire so as to be interactive with air pressure in the tire for selectively measuring a pressure in the tire, a controller, and a display. The tire condition monitor includes a transmitter and a receiver. The controller also has a transmitter and a receiver connected thereto, and the condition monitor and controller communicate via radio signals. An air compressor is mounted to a wheel of the tire so as to deliver air to an interior of the tire when the pressure of the tire is below a predetermined value. A power generator is connected to the wheel of the tire and includes an alternator magnet assembly and an induction coil assembly which are connected to the wheel of the tire such that relative rotation occurs therebetween as the tire rotates. FIG. 7 illustrates a tire pressure sensor, a temperature sensor, and a pick-up coil for revolution counting, all connected to the microprocessor chip of the condition monitor. The revolution counter is said to be usable xe2x80x9cin place of [a] hubometer.xe2x80x9d
U.S. Pat. No. 5,667,606, (referred to hereinbelow as the xe2x80x9cRenier/Cycloid ""606 Patentxe2x80x9d) incorporated in its entirety by reference herein, discloses a tire pressurizing and regulating apparatus comprising a displacement type air pump axially mounted on a vehicle wheel with an air pressure connection conduit introducing air under pressure generated from the pump into the pneumatic tire. A conventional [mechanical] pressure level mechanism is also provided and connected to the pump for establishing and maintaining a desired air pressure in the tire at a predetermined level. A cam and cam follower arrangement is mounted in the housing for the pump, and a pendulum is mounted for free axial rotation relative to the pump housing. The pendulum is connected to one of the cam or cam follower, and the other is secured to the pump housing for rotation therewith to provide a cam actuated driving movement for the pump.
U.S. Pat. No. 4,742,857, incorporated in its entirety by reference herein, discloses a tire pressure sensor and air supply to maintain desired tire pressure. The disclosed system for detecting the air pressure in each wheel (by means of a moveable magnet pressure sensor) and for effecting inflation or deflation in each wheel (by means of a valve connected to the moveable magnet) while the vehicle is operating, includes a controller and a high pressure reservoir mounted on each wheel. A data processor displays the tire pressure to the vehicle operator and allows for manual actuation of the valve for raising or lowering of the tire pressure.
U.S. Pat. No. 5,413,159, incorporated in its entirety by reference herein, discloses a self regulating tire pressure system and method which employs a bistable valve that allows air from a high pressure reservoir (mounted on the wheel) to replenish the pressure within a tire when it has fallen below an actuating pressure, and discontinues its operation only after the tire pressure has increased to a closing pressure that is greater than the actuating pressure. The system is capable of sensing the frequency, number and duration of the valve""s operations as indications of a slow tire leak, a flat, or a low reservoir pressure condition, respectively.
In a variation that does not require an air pressure supply mounted on the tire, Brazilian Patent No. PI 9603529-3A, incorporated in its entirety by reference herein, discloses a system with one or more minicompressors with pressure sensors mounted in the vehicle and coupled to the tires by means of rotating air couplings.
According to an aspect of the invention, a system for monitoring pneumatic tire conditions for one or more tire/wheel assemblies mounted on a vehicle, each tire/wheel assembly comprising a tire mounted on a wheel or wheel carrier, is characterized by: a wheel or wheel carrier transponder with a wheel or wheel carrier antenna mounted on the wheel or wheel carrier of the one or more tire/wheel assemblies for transmitting a signal indicating the rotational angular position of the wheel or wheel carrier; one or more receivers each having one or more receiving antennas fixedly mounted on the vehicle, the one or more receiving antennas being positioned to receive the signal from a specific one of the tire/wheel assemblies; and circuitry for processing the signals received by the one or more receiving antennas to determine the rotational angular position of the wheel or wheel carrier of the one or more tire/wheel assemblies.
According to an aspect of the invention, at least one of the wheel or wheel carrier antennas is substantially circular and includes a plurality of reactive circuit affecting elements incorporated into and spaced about the circumference of the at least one wheel or wheel carrier antenna for causing blips which are indicative of the rotational angular position of the wheel or wheel carrier antenna to occur in the signal received by the receiving antenna which is positioned to receive the signal from the at least one wheel or wheel carrier antenna.
According to an aspect of the invention, at least one of the wheel or wheel carrier antennas is a conductive hoop coupled to the wheel or wheel carrier transponder; and each conductive hoop wheel or wheel carrier antenna includes a plurality of reactive circuit affecting elements incorporated into and spaced about the circumference of the conductive hoop wheel or wheel carrier antenna for causing blips which are indicative of the rotational angular position of the conductive hoop wheel or wheel carrier antenna to occur in the signal received by the receiving antenna which is positioned to receive the signal from the at least one wheel or wheel carrier antenna.
According to an aspect of the invention, a method for monitoring pneumatic tire conditions for one or more tire/wheel assemblies each comprising a tire mounted on a wheel or wheel carrier, is characterized by the step of comparing the rotational angular position of a tire to the rotational angular position of the wheel or wheel carrier in the tire""s tire/wheel assembly in order to determine operating conditions of the tire.
According to an aspect of the invention, the method can include further determining pneumatic tire conditions by monitoring one or more of a tire pressure, a tire temperature, and a count of tire revolutions.
According to an aspect of the invention, the method can include measuring the rotational angular position of a radially outer portion of the tire by means of an RF signal transmitted by an antenna mounted inside the tire near the outer circumference of the tire.
According to another aspect of the invention, a system for monitoring pneumatic tire conditions for one or more tire/wheel assemblies mounted on a vehicle, each tire/wheel assembly comprising a tire mounted on a wheel or wheel carrier, is characterized by: a wheel or wheel carrier transponder with a wheel or wheel carrier antenna mounted on the wheel or wheel carrier of the one or more tire/wheel assemblies for transmitting a first signal indicating the rotational angular position of the wheel or wheel carrier; a tire transponder with a tire antenna mounted on the tire of the one or more tire/wheel assemblies for transmitting a second signal indicating the rotational angular position of the tire; one or more receivers each having one or more receiving antennas fixedly mounted on the vehicle, the one or more receiving antennas being positioned to receive the first signal and the second signal from a specific one of the tire/wheel assemblies; and circuitry for processing the first and second signals received by the one or more receiving antennas to determine the rotational angular position of the tire relative to the wheel of the one or more tire/wheel assemblies.
According to an aspect of the invention, at least one of the tire antennas is substantially circular and includes a plurality of reactive circuit affecting elements incorporated into and spaced about the circumference of the at least one tire antenna for causing blips which are indicative of the rotational angular position of the tire antenna to occur in the second signal received by the receiving antenna which is positioned to receive the second signal from the at least one tire antenna. Preferably, the at least one tire antenna which includes a plurality of reactive circuit affecting elements is mounted near the outer circumference of the tire.
According to an aspect of the invention, at least one of the wheel or wheel carrier antennas is substantially circular and includes a plurality of reactive circuit affecting elements incorporated into and spaced about the circumference of the at least one wheel or wheel carrier antenna for causing blips which are indicative of the rotational angular position of the wheel or wheel carrier antenna to occur in the first signal received by the receiving antenna which is positioned to receive the first signal from the at least one wheel or wheel carrier antenna.
According to an aspect of the invention, at least one of the tire antennas is a conductive hoop coupled to the tire transponder; and each conductive hoop tire antenna includes a plurality of reactive circuit affecting elements incorporated into and spaced about the circumference of the conductive hoop tire antenna for causing blips which are indicative of the rotational angular position of the conductive hoop tire antenna to occur in the second signal received by the receiving antenna which is positioned to receive the second signal from the at least one tire antenna. Preferably, the at least one conductive hoop tire antenna which includes a plurality of reactive circuit affecting elements is mounted near the outer circumference of the tire.
According to an aspect of the invention, at least one of the wheel or wheel carrier antennas is a conductive hoop coupled to the wheel or wheel carrier transponder; and each conductive hoop wheel or wheel carrier antenna includes a plurality of reactive circuit affecting elements incorporated into and spaced about the circumference of the conductive hoop wheel or wheel carrier antenna for causing blips which are indicative of the rotational angular position of the conductive hoop wheel or wheel carrier antenna to occur in the first signal received by the receiving antenna which is positioned to receive the first signal from the at least one wheel or wheel carrier antenna.
According to an aspect of the invention, a sub-receiver is associated with each of the one or more receiving antennas; and the sub-receivers assist a single receiver in processing the signals.
According to an aspect of the invention, there can be one receiving antenna for each specific tire/wheel assembly; and each receiving antenna is configured to receive the first signal at a first frequency from the wheel or wheel carrier antenna of the specific tire/wheel assembly, and is configured to receive the second signal at a second frequency from the tire antenna of the specific tire/wheel assembly. Alternatively, there can be a tire receiving antenna for each specific tire antenna, wherein the tire receiving antenna is positioned by fixedly mounting it on a wheel housing in close proximity to the tire antenna on the tire; and there is a wheel or wheel carrier receiving antenna for each specific wheel or wheel carrier antenna, wherein the wheel or wheel carrier receiving antenna is positioned by fixedly mounting it on an axle housing in close proximity to the wheel or wheel carrier antenna on the wheel or wheel carrier.
According to an aspect of the invention, one or more of the tire transponders and of the wheel or wheel carrier transponders is a passive transponder; and the receiver and receiving antenna associated with each of the one or more passive transponders transmit an interrogating signal to the associated passive transponder.
Other objects, aspects, features and advantages of the invention will become apparent in light of the following description thereof.


Flange-to-flange connectors and construction methods using such connectors are disclosed. The connector may include a first and second anchored plates secured to a first and second sets of anchoring bars. The connector may also include a first and second alignment plates configured to mate with the first and second anchored plates. The connector may further include at least one shim configured to be positioned between the first and second anchored plates. A bolt may be configured to secure the first and second alignment plates with the first and second anchored plates, respectively, and when the bolt is tightened, the bolt pulls the first and second alignment plates and the first and second anchored plates together to form a rigid connection, which may eliminate the need to form and cure concrete at job sites, allowing the time, cost, and construction complexity to be reduced significantly compared to conventional connection systems.

A double tee beam is a load-bearing structure that resembles two T-beams connected to each other side by side. The strong bond of the flange (horizontal component) and the two vertical components (also known as stems) creates a structure that is capable of withstanding high loads while having a long span. Floor systems of modern parking structures, for example, use precast double tee beams, which are joined flange-to-flange using connectors anchored in the flange of the double tee beams, to form an integral multi-beam floor.
A type of conventional flange-to-flange connector uses a thin twisted plate pre-embedded in the flange. Two twisted plates aligned with each other across the gap between double tees are welded together at the jobsite using a loose steel plate to connect the flanges. This type of flange-to-flange connector creates a flexible connection, which has been criticized for lack of fatigue capacity and failure of welds if the welding is not done properly by certified welders. In addition, this type of flange-to-flange connector requires caulking (sealant) to seal the gap between the flange edges, with a life expectancy of five to ten years, thus requiring significant maintenance expenses.

Flange-to-flange connection of precast concrete members


A coupling structure includes a single mode active device and a planar optical waveguide. Specifically, the planar optical waveguide includes a silica waveguide for transmitting an optical signal, where the silica waveguide includes a coupling section and a conduction section; the coupling section is of a regular trapezoidal structure or an inverted trapezoidal structure, where a surface of the coupling section coupled to the single mode active device is a trapezoid top, and a surface of the coupling section connected with the conduction section is a trapezoid bottom; and a coupling gap is preset between the single mode active device and the planar optical waveguide.

At present, mainstream 40G/100G optical modules are basically implemented through free-space coupling technologies based on prisms, lenses, optical filters, and the like, and are characterized in a complicated process, a need for active alignment, high packaging costs, and a great difficulty in larger-scale integration.
On the other hand, a photonic integration technology generally means that active devices (lasers, detectors, optical amplifiers, optical modulators, and the like) and passive devices (optical splitters/combiners, optical filters, optical multiplexers/demultiplexers, and the like) are integrated to implement a monolithic multi-functional optical device technology. The photonic integration technology is considered as a powerful optical module technology in the near future and especially in short-range optical interconnect applications such as data centers. However, how to effectively couple light of a single mode laser to a planar optical waveguide (also known as Planar Lightwave Circuit, PLC) or other silicon-based optical integrated chips is still a big issue at present. In addition to the coupling efficiency, how to make the process simple and practicable and use automatic devices to achieve the effect of reducing costs is also an important issue.

Planar optical waveguide structure, and coupling structure thereof and coupling method thereof

Wuhan Telecommunication Devices Co., Ltd.


An ultrasonic motor includes a vibrator formed by stacking a plurality of rectangular piezoelectric plates in a thickness direction, a driving circuit for applying a driving signal to a piezoelectric plate, and a detection circuit for detecting an electromotive force generated when the piezoelectric plate deforms, and this ultrasonic motor is configured in such a manner that there are a first piezoelectric plate and a second piezoelectric plate among the plurality of rectangular piezoelectric plates, the first and the second piezoelectric plate each is a piezoelectric plate in which a longitudinal vibration polarization portion that can excite longitudinal vibrations and a bending vibration polarization portion that can excite bending vibrations are polarized in a thickness direction, and the first piezoelectric plate is connected to the driving circuit and the detection circuit, and the second piezoelectric plate is connected to the driving circuit and is not connected to the detection circuit.

1. Field of the Invention
The present invention relates to an ultrasonic motor for use in such fields as controlling a microscope stage, in which positioning steps are required.
2. Description of the Related Art
In recent years, ultrasonic motors that realize high-speed operations and inching operations over a relatively wide range while being able to be configured to be small in size have gathered interest as actuators for precision instruments. One of the ultrasonic motor types is the ultrasonic motor that is configured as disclosed in Patent Document 1 (Japanese Patent No. 2722211), Patent Document 2 (Japanese Patent Application Publication No. 2004-201380), and Patent Document 3 (Japanese Patent Application Publication No. 2005-295656). The ultrasonic motor disclosed in these documents employs a configuration in which the longitudinal vibrations (also referred to as the stretching vibrations) and the bending vibrations are excited at the same time, and thereby elliptical vibrations are caused at the position at which the ultrasonic motor contacts the driven object in order to move the driven object in desired directions. A piezoelectric body is commonly employed as a material for the ultrasonic motors. By applying alternating currents having different phases to a longitudinal vibration electrode and a bending vibration electrode formed on the piezoelectric body, the elliptical vibrations are caused. Because of the application of the alternating currents having different phases, when the deformation direction of the longitudinal-vibration-electrode portion in the piezoelectric body and that of the bending-vibration-electrode portion in the piezoelectric body overlap each other, one electrode portion in the piezoelectric body may be forced to shorten while the other electrode portion stretches.
Also, the ultrasonic motors are configured to achieve a large vibration amplitude by utilizing their own resonance frequency. Accordingly, when the resonance frequency that was set as the initial setting is changed due to a change in the ambient temperature or in the contacting state between the motor and the driven object, the vibration amplitude becomes smaller and the moving distance of the driven object is affected. In order to cope with this problem, an ultrasonic motor as disclosed in FIG. 4 of Patent Document 4 (Pamphlet of WO 04/088830) is suggested in which a vibration detection electrode is provided for monitoring the vibrating state of the vibrator.
Also, when an ultrasonic motor is to be used in a state in which it is incorporated with a microscope stage or the like, pre-load has to be applied to the vibrator to some extent in order to prevent the movable portions of the stage from being moved easily (for example, a pre-load of about 20 N is required in order to achieve a holding force of about 5 N). This condition requires the ultrasonic motor to be able to output power that is sufficiently high, and also to be rigid, which is achieved by using materials that are thick enough and wide enough to sustain such a pre-load. In order to meet this requirement, a larger current has to flow to the driving electrodes, especially if the total amount of the current flowing to the GND becomes large because the current that has flowed to the respective driving electrodes flows to the GND. In the case of, for example, the vibrator disclosed in Patent Document 5 (Japanese Patent Application Publication No. 2005-65358), there is only one GND electrode while there are four driving electrodes, and there is only one connecting point for the lead wire. Accordingly, in order to prevent the lead wire of the GND from being disconnected due to heat or the like, a lead wire having a larger diameter is required for allowing larger current to flow.


A board game in which the game board is marked to form an endless main path simulating the main corridor of a shopping mall. Additional markings define endless branch paths simulating individual stores in the shopping mall. Playyers acquire the right to purchase specific items of merchandise in the branch paths by landing on specific spaces in the main path and picking merchandise items cards from a pack of cards. Other spaces on the main path direct the player to a spinner mechanism which can be used to obtain play money with which to purchase specific items of merchandise. The aim of the game is to purchase the highest possible dollar value of merchandise.

This invention relates to a board game wherein each player has a token that can be moved along a main path and a series of branch paths marked on the game board surface. The main path is marked to simulate the main corridor of a shopping mall, whereas the branch paths are marked to simulate individual stores in the shopping mall.
Various board games have been devised, e.g. the well known game called MONOPOLY. Other board games are shown in U.S. Pat. Nos. 4,452,457 to Atieh et al, 4,480,838 to A. Aharonian, 4,566,697 to K. Vickers, 4,856,788 to M. Fischel.
The present invention relates to a board game wherein the game board is marked to simulate a shopping mall. A main endless path is marked on the board to represent the main corridor of the shopping mall. Branch paths connect with the main path at spaced points therealong; each branch path represents an individual store in the mall, e.g. a clothing store or an appliance store. Each path is subdivided into discrete spaces adapted to accommodate a player's token. Each player rolls a set of device to determine how many spaces his/her token will be advanced along the main path or a selected branch path during each player's turn.
Some of the spaces in the main path are marked to direct the player landing thereon to pick a card from a pack of Merchandise Cards. When the player receives such a card he/she is entitled to move the token along a path leading to a space in one of the branch paths marked with the particular item of merchandise indicated on the card. The winning player is the person who accumulates the greatest merchandise dollar value in a given period of time. Alternately, the winner can be the first player to accumulate a given merchandise dollar value.
The game board is designed so that each player is given multiple choices as to how his/her token is advanced along the board. The game involves a combination of luck and skill.


Creating a sub-titles stream or file composed of sub-titles elements. For each sub-titles element in said sub-titles elements, a sub-titles element is inserted into the sub-titles stream or file, at least one end-of-block condition related to a mode of presentation of sub-titles is verified, and a datum representative of an end of a block according to the mode of presentation of sub-titles is inserted into the sub-titles stream or file upon satisfying said at least one end-of-block condition. A sub-titles stream or file may be presented on a terminal of a user by selecting on the terminal a mode of presentation of sub-titles, reading a sub-titles block associated with the mode of presentation in the stream or file, and presenting on the terminal the at least one sub-titles block according to the mode of presentation.

The application of sub-titles is an important element in video stream production. Sub-titles enable a user to have a better understanding of the content of the video, and particularly of the speech uttered, when the latter is hardly, if at all, understandable. This is particularly useful when a program is transmitted in a language not known to the user or when the auditory perception of the language is disturbed by poor transmission, poorly articulated speech, or background noise. Sub-titles also enable the hard of hearing to achieve an understanding of the program.
The application of sub-titles may be performed either offline or in real time (so-called live sub-titles in the parlance of the art). The application of sub-titles offline is performed on a support prepared in advance. This type of sub-titling is found, for example, in DVDs, Blu-ray discs, or transmissions broadcast offline. This offline application does not present any particular time constraint. Thus, it is possible in this case to manually insert sub-titles into the video stream, an operator verifying that the sub-titles are perfectly synchronized with the video, while presenting a visual aspect perceived to be pleasant by the user. Although subjective, this notion of pleasant perception of the sub-titles can be reduced to objective elements, for example, obtaining sub-titles which are displayed at a moderate speed, or which retain a fixed position with respect to the screen. It is also possible to use audio analysis schemes which may turn out to be expensive in calculation time to best synchronize the sub-titles and the audio/video.
On the other hand, it is not possible to use these techniques in the case of live sub-titles, as in this case the video content produced is transmitted immediately. The production of live sub-titles is generally performed by an operator producing the sub-titles live and dispatching them in the stream. This operation produces an inevitable lag between the moment at which the video is transmitted and the moment at which the corresponding sub-title is produced. This lag is still more significant when the task of the operator induces a translation from one language to the other for the production of the sub-titles.
The approach generally used to process live sub-titles is to transmit each word of sub-titles as soon as it is available in order not to add any further lag. However, this approach has drawbacks, e.g., in addition to an inevitable lag, the words arrive one after another, not always forming a coherent whole. Moreover, when the sub-titles are formed on the basis of a teletext source, a line feed may entail an upwards shift of the words. This upwards shift, or "shift up" as it is called, consists, when a new line of sub-titles begins, in shifting the set of lines of sub-titles by one line upwards and in deleting the oldest line. This effect may be particularly disturbing for the viewer, since if a word that he was reading is shifted upwards, he will have to make an additional effort to follow this word while retaining the overall sense of the sub-title.
Live sub-titles are thus often perceived by users as unpleasant and of poor quality. The presentation of the words of sub-titles has been listed as one of the main causes of poor perception of live sub-titles by users by Ofcom (Office of Communications), The quality of live subtitling, pp. 29-30. According to this study, users seem to prefer sub-titles presented in blocks. However, the definition of a "block" remains broad, and certain users may prefer sub-titles presented line by line, whereas other users may prefer sub-titles presented sentence by sentence, while other users might prefer sub-titles presented on a word by word basis.
The known schemes of the prior art involve producing or updating a page of sub-titles in a video encoder. The sub-titles can be encoded in the form of images, such as for example in the DVB-SUB standard (the acronym standing for Digital Video Broadcasting Subtitles). In this case, the style of sub-titles (colour, size of the characters, etc.) is defined by the image.
Sub-titles may also be encoded in the form of textual characters, such as for example in the various standards based on W3C TTML (the acronym standing for World Wide Web Consortium Timed Text Markup Language). In this case, the sub-titles are stored in the form of characters forming words as in a text file, and optionally header information that specifies a presentation style to be applied. The presentation style may contain information such as the size of characters to be applied, the font, and the like. By way of example, the presentation styles available in the EBU-TT standard (the acronym standing for European Broadcasting Union-Timed Text), arising from W3C TTML, are described in the document EBU-UER, EBU-TT Part 1, Subtitling format definition.
U.S. Pat. No. 8,695,048 describes an approach for transcribing sub-titles for the deaf and hard of hearing from a first format to a second format independent of the platform. The second format can be based on the DVB-SUB standards or standards based on W3C TTML, such as for example EBU-TT or SMPTE-TT (the acronym standing for Society of Motion Picture and Television Engineers-Timed Text).
U.S. Pat. No. 5,497,241 (the '241 patent) describes a system making it possible to display sub-titles by blocks in a video. The blocks in the '241 patent are predefined blocks where each block is associated with a particular language. Thus, the choice of the language determines the form of the blocks and of the presentation.
The standards and techniques for coding sub-titles available today therefore make it possible to represent sub-titles with varied styles (different character fonts essentially), separate these sub-titles into blocks, and display the sub-titles blocks according to a desired style.

Controlling modes of sub-title presentation


An ultrasonic probe for observing an object by emitting an ultrasonic wave to the object and detecting another ultrasonic wave reflected from the object comprises: a flexible tube; an ultrasonic transducer disposed within the tube rotatably about an axial center of the tube; and a rotational information detecting apparatus for detecting rotational information of the ultrasonic transducer which includes: a signal generating surface disposed in the tube coaxially with respect to the axial center of the tube and having reflecting portions and non-reflecting portions formed alternately and repeatedly; at least one optical fiber arranged along and near the axial center of the tube, for guiding a light beam to be irradiated upon the signal generating surface from an end surface of the optical fiber and for receiving and guiding an optical signal reflected from the signal generating surface at the end surface thereof; and an optical signal detecting section for detecting the rotational information on the basis of the optical signal guided through the optical fiber. Since the optical fiber for guiding a light beam to be irradiated upon the signal generating surface and further the optical signal reflected from the signal generating surface is disposed in the vicinity of the axial center of the tube, even when the ultrasonic probe is bent, it is possible to reduce the expansion and contraction rate of the optical fiber to such a small range as with the case where the optical fiber is bent at the axial center, thus preventing the optical fiber from being damaged or cut off and improving the transmission characteristics of the optical fiber.

1. Field of the Invention
The present invention relates to an ultrasonic probe used for an ultrasonic diagnosis apparatus inserted into a body cavity to observe an internal organ, and in particular to an ultrasonic probe for detecting and transmitting rotational information of an ultrasonic transducer disposed in a tubular member rotatably about an axis thereof through an optical fiber.
2. Description of the Prior Art
As the ultrasonic diagnosis apparatus inserted into a body cavity for observation of the motion or the texture of an internal organ, an ultrasonic probe of mechanical scanning type is so far known, in Japanese Published and Examined Utility Model Application No. 62-7301, for instance.
FIG. 1 is a cross-sectional view showing the conventional ultrasonic probe. In the drawing, an ultrasonic transducer 3 fitted to an ultrasonic scanning member 2 is disposed in an end portion of a flexible cylindrical casing 1. The ultrasonic scanning member 2 is fitted to a rotary axle 4 disposed at an axial center of the cylindrical casing 1 so as to be rotatable together with the rotary axle 4 in the cylindrical casing 1.
Further, a disk 6 having a signal generating surface 5 on which reflecting portions and non-reflecting portions are formed alternately and repeatedly is fixed to this rotary axle 4. The disk 6 rotates together with the rotary axle 4 and therefore together with the ultrasonic transducer 3.
Further, a light emitting optical fiber 7 and a light receiving optical fiber 8 are both arranged along the rotary axle 4 in the vicinity of the inner circumferential surface of the cylindrical casing 1.
The disk 6, the light emitting optical fiber 7 and the light receiving optical fiber 8 constitute a rotational information detecting apparatus for detecting rotational information of the rotary axle 4 such as rotational angles and rotational angular velocity of the rotary axle 4.
On the other hand, an ultrasonic drive signal for driving the ultrasonic transducer 3 and a received ultrasonic signal reflected from a body cavity 10 are transmitted through a signal cable 9 arranged in the rotary axle 4.
In operation, when the ultrasonic probe is inserted into a body cavity, the motion or the texture of the internal organ can be observed by rotating the ultrasonic transducer 3. Here, the ultrasonic transducer 3 is rotated via the ultrasonic scanning member 2 rotated by the rotary axle 4 driven by a motor (not shown).
A light beam is emitted from an end of the light emitting optical fiber 7 to the signal generating surface 5. Since the reflecting portions and the non-reflecting portions are formed alternately and repeatedly on the signal generating surface 5, when the disk 6 rotates, a light beam emitted from the light emitting optical fiber 7 is reflected from the signal generating surface 5 as an optical signal. Here, the optical signal received by an end of the light receiving optical fiber 8 changes in light intensity with respect to time, so that it is possible to detect the rotational information (e.g., the rotational angle and the rotational angular velocity) of the rotary axle on the basis of the received optical signal.
An output terminal of the light receiving optical fiber 8 is connected to a control section of the motor for driving the rotary axle 4. The rotational information detecting apparatus and the control section of the motor for driving the rotary axle 4 are connected so as to form a closed loop, so that the rotational angle and the angular velocity of the rotary axle 4 can be controlled on the basis of the rotational information.
However, the conventional ultrasonic probe involves the following problems:
The optical fiber bundle composed of the light emitting optical fiber 7 and the light receiving optical fiber 8 is arranged in the vicinity of the inner circumferential surface of the cylindrical casing 1; that is, the optical fiber bundle is positioned radially outward away from the rotary axle 4. Therefore, when the ultrasonic probe is inserted into a curved body cavity 10 as shown in FIG. 2, the rate of expansion and contraction of the optical fibers 7 and 8 differs largely according to the curvature direction of the optical fiber bundle, so that there exists a problem in that the optical fibers are damaged or cut off because the expansion and contraction rate of the optical fiber exceeds its allowable range according to the curvature direction.
In addition, since the optical fibers are arranged in the vicinity of the inner circumferential surface of the cylindrical casing 1, the expansion and contraction rate of the optical fibers 7 and 8 is larger than that of the cylindrical casing 1 at its axial center. Therefore, there exists another problem in that the transmission characteristics of the optical signal are subjected to change due to a large distortion generated in the optical fiber, thus it has been difficult to obtain an accurate rotational information of the rotary axle 4.


An earnings volatility reduction procedure includes determining a first sensitivity value of a portfolio to underlying market conditions, trading in an immunizing instrument having a second sensitivity value substantially equal in magnitude and opposite in value of the first sensitivity value, and trading in a qualifying instrument having a third sensitivity value substantially equal to the first sensitivity value. A derivative portfolio (in particular, one that includes a financial instrument for which changes in value are characterized as earnings pursuant to FAS 133) is structured by determining a sensitivity of the derivative portfolio with respect to financial conditions in a trading market, executing an immunizing purchase of a second trading instrument in an amount equal to the magnitude of the current sensitivity and opposite in value, and executing a qualifying sale of a third trading instrument in an amount equal to amount of the current sensitivity.

Financial Accounting Standards Board Statement No. 133 (FAS 133) ("Accounting for Derivative Instruments and Hedging Activities"), as amended by Financial Accounting Standards Board Statement No. 138 (FAS 138), establishes accounting and reporting standards for derivative instruments and for hedging activities. Briefly, FAS 133 requires that an entity recognize all derivatives as either assets or liabilities in the statement of financial position and measure those instruments at fair value. If certain conditions are met, a derivative may be specifically designated as (a) a hedge of the exposure to changes in the fair value of a recognized asset or liability or an unrecognized firm commitment, (b) a hedge of the exposure to variable cash flows of a recognized asset, liability or of a forecasted transaction, or (c) a hedge of the foreign currency exposure of a net investment in a foreign operation, an unrecognized firm commitment, an available-for-sale security, or a foreign-currency-denominated forecasted transaction.
The accounting for changes in the fair value of a derivative (that is, gains and losses) depends on the intended use of the derivative and the resulting designation.                For a derivative designated as hedging the exposure to changes in the fair value of a recognized asset or liability or a firm commitment (referred to as a fair value hedge), the gain or loss is recognized in earnings in the period of change together with the offsetting loss or gain on the hedged item attributable to the risk being hedged. The effect of that accounting is to reflect in earnings the extent to which the hedge is not effective in achieving offsetting changes in fair value.        For a derivative designated as hedging the exposure to variable cash flows of a forecasted transaction (referred to as a cash flow hedge), the effective portion of the derivative's gain or loss is initially reported as a component of other comprehensive income (OCI) (outside earnings) and subsequently reclassified into earnings when the forecasted transaction affects earnings. The ineffective portion of the gain or loss together with any excluded portion is reported in earnings immediately.        For a derivative designated as hedging the foreign currency exposure of a net investment in a foreign operation, the effective portion of the gain or loss is reported in other comprehensive income (outside earnings) as part of the cumulative translation adjustment. The accounting for a fair value hedge described above applies to a derivative designated as a hedge of the foreign currency exposure of an unrecognized firm commitment or an available-for-sale security. Similarly, the accounting for a cash flow hedge described above applies to a derivative designated as a hedge of the foreign currency exposure of a foreign-currency-denominated forecasted transaction.        For a derivative not designated as a hedging instrument, the gain or loss is recognized in earnings in the period of change.
One of the requirements for hedge accounting when using a derivative is that changes in the value of the derivative must be expected to be highly effective in offsetting changes in value (or projected cash flows) of the hedged item. When hedging with options, one issue that may arise under FAS 133 is whether changes in time value can be included in the assessment of hedge effectiveness. In a totally static hedge strategy in which the hedged items do not contain embedded options, changes in time value would generally not offset changes in fair value or projected cash flows. To allow purchased options to qualify for hedge accounting, FAS 133 permits exclusion of all or a part of the hedging instrument's time value from the assessment of hedge effectiveness. If time value is excluded from the assessment of the hedge effectiveness, then the change in the time value would have to be recognized in earnings as they occur. FAS 133 suggest two methods that can be used with respect to excluding time value changes: (i) time value being computed as the fair value of the option minus the intrinsic value; and (ii) time value being computed as the fair value of the option minus the minimum value.
FAS 133 requires derivatives to be highly effective if they are to qualify for hedge accounting. The decision of how hedge effectiveness will be measured affects the determination of whether an item is (likely to be) highly effective and potentially the amount deferred in other comprehensive income (OCI). To be eligible for hedge accounting, FAS 133 requires "Both at inception of the hedge and on an ongoing basis, the hedging relationship is expected to be highly effective in achieving offsetting changes in fair value (cash flow) attributable to the hedged risk during the period that the hedge is designated." (par. 20b/28b). The Statement notes (par. 389) "The Board intends "highly effective" to be essentially the same as the notion of "high correlation" in Statement 80."
In hedging with purchased options, ineffectiveness can arise due to the dynamic nature of market prices. For example, large moves in spot prices can introduce hedge ineffectiveness. This results from the fact that the option price is a convex function of the spot rate, whereas the value of the hedged item is linear in spot. In addition, because the option price is a function of volatility, whereas the value of the underlying is not, changes in market volatility can lead to hedge ineffectiveness. It is noted that the change in value of an option due to changes in volatility can be excluded from the test of effectiveness; however, if this were done, changes due to volatility would have to be reported in earnings. Furthermore, the value of an option may change with time, while the value of the hedged item does not. It is noted that the change in the value of the option due to changes in time may be excluded from the test of effectiveness; however, if this is done, changes due to time decay would have to be reported in earnings.
Methods for determining whether a hedge is highly effective include (i) the cumulative offset method or (ii) by the rolling historical correlation method. Cumulative offset methodology measures effectiveness by dividing the cumulative change in value of the derivative with the cumulative change in either fair value or projected cash flows of the item being hedged. A hedge may be viewed as effective when the cumulative offset ratio calculated by comparing these two numbers is within a range of approximately 80% to 125%. Rolling historical correlation methodology can be used before hedge inception to determine whether the application of hedge accounting is reasonable given past results. This method may also be used to measure ongoing effectiveness once a hedge is put in place. For example, the company decides to measure effectiveness based on a rolling two year correlation. 3 months into a hedge, it will measure correlation based upon the trailing 2 years which will include the 3 months' hedge results plus the 21 months' prior to putting the hedge in place. An r-squared of approximately 0.8 (correlation coefficient of 0.894) is generally considered sufficient for a company to apply hedge accounting.
With respect to options, one hedging method in which changes in time value (or at least those unrelated to changes in volatility) are considered "effective" is a so-called delta-neutral hedge. FAS 133 specifically permits a type of delta-neutral hedging in which a company hedges a fixed cash position by adjusting the notional amount of the option it owns (FAS 133, paragraphs 85-87). More specifically, FAS 133 permits a company to monitor an option's 'delta'—the ratio of changes in the option's price to changes in the price of the underlying. As the delta ratio changes, the company buys or sells put options so that the next change in the fair value of all the options held can be expected to counterbalance the next change in the value of (the underlying)." In general, for Call options hedging a strengthening underlying, the delta ratio moves closer to one (i.e., 100%) as the underlying strengthens and moves closer to zero as the underlying weakens. The delta ratio also changes as the time to expiry decreases, as interest rates change, and as implied volatility changes.
In some cases, delta neutral hedging of a fixed cash position achieved through adjustments to the notional amount of an option, as disclosed by FAS 133, is undesirable because it changes the economics of the strategy from, for example, a simple option purchase. Consequently, other "effective" hedging strategies compatible with a wide range of desired economic outcomes are desirable.

Reduction of financial instrument volatility


A milking parlor assembly including a brisket rail therefor. The brisket rail is formed of sheets of steel that are bent into six-sided segments that are relatively easy to manufacture and, when assembled into the brisket rail, very easy to clean and maintain.

Systems and methods for milking cows comprise a milking machine system and a milking parlor system. The milking machine system milks the cows and conveys the milk to a storage tank for further processing, packaging, and the like. The present invention does not relate to milking machine systems and may be used with any conventional milking machine system of appropriate size and capacity.
A primary function of the milking parlor system is physically to arrange and restrain the cows within a milking area during the milking process. The present invention is of particular advantage when applied to milking parlors that are designed to arrange cows in what is referred to as a "herringbone" arrangement during milking. When in a herringbone arrangement, cows are arranged at a slight angle within the milking area such that the head of a middle cow is slightly in front of the head of the cow to one side and slightly behind the head of the cow to the other side.
Secondary functions of the milking parlor system are to allow the cows to be led into and released from the milking area prior to and after milking in a quick and orderly manner.
Beyond these basic functions, a milking parlor system must operate reliably several times a day, seven days a week, for many years. Such a system must also be easy to clean and withstand the effects of repeated washings. Because cows are large and heavy, the milking parlor system must be sufficiently rigid and durable to withstand the force of the cows thereon. And like all products that are sold in a competitive environment, the costs of producing milking parlor systems must be kept as low as possible.
The need thus exists for improved milking parlors that effectively maintain cows in a herringbone arrangement, that may be used in a system that facilitates ingress and egress of cows, that are rigid, durable, and reliable, that are easy to clean, and that may be manufactured efficiently and inexpensively.


A method of manufacturing thread-stitched books and an arrangement for carrying out the method, the method including gathering individual folded printed sheets into sheet blocks in a gathering unit, and loading after each gathering cycle the sheet blocks onto a block receiving unit of a storage unit releasably connected to the gathering unit. Batches of the sheet blocks are supplied to at least one book sewing machine. Subsequently, the sheets are sewn together into book blocks in the at least one book sewing machine.

1. Field of the Invention
The present invention relates to a method of manufacturing thread-stitched books. The method includes gathering folded printed sheets into blocks and later binding the printed sheets into a book block by sewing the individual printed sheets together.
The present invention further relates to an arrangement for carrying out the above-described method. The arrangement includes a gathering unit with several feeder stations for different printed sheets and at least one subsequently arranged book sewing machine.
2. Description of the Related Art
In a machine arrangement for thread-stitching of book blocks disclosed in CH-A-503,595, blocks manufactured from printed sheets in a gathering machine or device are transferred at the stack discharge or delivering unit to a coplanar conveyor belt. Feeders of a book sewing machine for the blocks are arranged along the conveyor belt. Operating personnel load the blocks arriving on the conveyor belt onto the feeders. In a method carried out on the machine arrangement of CH-A-503,595, the blocks are placed on pallets at the end of the gathering machine and the pallets are moved into a storage area until the blocks are further processed in the book sewing machines. The filled pallets are transported from the storage area to the feeders of the book sewing machines and the blocks are manually placed in the feeders.
In newer arrangements, a machine is used for loading the book sewing machine directly from the gathering unit.
The manual loading is very labor intensive because the feeders of the book sewing machine or machines have to be loaded and/or the printed sheets gathered into blocks have to be placed into intermediate storage. The intermediate storage is necessary because of the output ratio between gathering unit and book sewing machine, wherein the gathering unit is capable of gathering a plurality of blocks during the time that the book sewing machine is capable of finishing a book block. The reason for the substantially longer processing time in the book sewing machine is the fact that each individual printed sheet of a block is being sewed. In other words, during each work cycle of the gathering unit, a block is made available at the delivery unit which cannot be processed completely by the book sewing machine within the same period of time because the capacity of the book sewing machine is smaller.
On the other hand, it would not be economical to increase the sewing capacity by increasing the number of book sewing machines and by providing extensive conveyor units when a greater order is to be filled.
When the gathering unit and the book sewing machine or machines are directly connected, an economical manufacture is only possible if a smaller number of units is to be produced, so that an intermediate storage of the blocks is not necessary. Other disadvantages of known arrangements of the above-described type are described in the relevant technical literature.

Method of manufacturing thread-stitched books and arrangement for carrying out the method


An upright for a lift truck includes a first group of mast sections in a first stagger arrangement where a first mast section of the first group of mast sections is fixed to the lift truck. The upright further includes a second group of mast sections in a second stagger arrangement that is reverse nested inside the first stagger arrangement. Further, the upright includes a drive system for telescopingly extending and retracting the second mast sections relative to the first mast section.

As is known, lift trucks are often used to lift and carry loads, such as rolled carpets. Lift trucks usually include: (a) steerable and drive wheels for propelling and maneuvering the lift truck over a surface, (b) an upright and carriage system for handling loads and (c) a power source and drive system for propelling the truck and operating truck systems including the upright and carriage system. Typically the uprights include multiple stages in order to allow the load to be lifted to a required height above ground level including, for example, up to twenty-eight feet above ground level. This allows loads to be positioned on storage racks, into over-the-road trailers, into ocean-going freight containers or the like.
The present invention relates to a five stage upright for a lift truck. Two different types of five stage uprights are known in the art. The first, known as a "six pack", incorporates two "triple stage" uprights that are fastened one in front of another. This arrangement uses a total of six rail sets or mast sections arranged generally as illustrated in FIG. 10a. The hydraulic systems for these uprights are designed for the normal six thousand to eight thousand pound loads of the truck models to which the six-pack upright is normally attached. The other method is known as "quad-plus-one". In a quad-plus-one upright a conventional four rail or "quad" upright has an additional rail set or mast section added in front of the existing four mast sections as illustrated in FIG. 10b.
The prior art six-pack and quad-plus-one uprights are effective to provide five stages to reach a given lift height. It should be appreciated, however, that each of these designs suffers from a number of significant draw-backs. In the case of the six-pack upright, six separate mast sections are utilized in order to provide a five stage lift. The extra mast section adds unnecessary weight to the upright which reduces load capacity and adversely affects the battery life of an electrically powered lift truck. The stacking of the mast sections in the fore/aft direction also increases the load center which further reduces lifting capacity. It also adds length to the truck thereby increasing the aisle space necessary to allow effective operation of the truck.
The quad-plus-one upright suffers from similar disadvantages. Once again, the fore/aft stacking of the mast sections increases the load center thereby reducing lifting capacity. It also increases the overall length of the truck thereby limiting operation of the truck to warehouses and areas with wider aisle ways. Since space within a warehouse is limited, wider aisle ways reduce available storage space which is a primary customer concern.
The present invention relates to a five stage upright specially designed to provide the desired relatively high lift height with a relatively low overall truck height that allows placing loads on racks up to twenty-eight feet in height as well as into over the road trailers and ocean going freight containers. The five stage upright rail configuration of the present invention has been widened to closely fit between the drive tires of the lift truck. The widening of the rail system adds to the lateral stability of the lift truck when under load.
The "rail nest" consists of five rails arranged with the innermost three rails with the same general arrangement as a three rail nested upright where the rails are staggered forward. The additional two rails in the five-stage located outboard of the inner three rails are staggered forward, but in an opposite direction, i.e., reverse nested. The result in that the depth or fore and aft dimension of the five stage rails is essentially the same as a three rail upright. This reduction in the dimension from the load face to the centerline of the drive wheels adds significantly to the load capacity of the lift truck.
There are some additional noteworthy advantages from the new arrangement. The most dramatic is the reduction of the load center: that is, the dimension from the centerline of the drive wheels to the load face. This represents a change from approximately 36 inches for the six-pack upright system and approximately 30 inches for the quad-plus-one upright system to 21.4 inches for the five stage upright of the current invention. This reduction in load center allows using a smaller upright system and a smaller base lift truck chassis to carry the same load. The nominal forklift chassis can be reduced from 8000 lb capacity with a service weight of 13,649 lb to a smaller 6500 lb capacity with a weight of 11,828 lb. The smaller chassis size reduces the initial cost as well as reducing the operating cost and energy consumption while doing the same work.
The space between the innermost rails is larger than with conventional designed five and six rail "narrow" uprights. This significantly improves the width of the "vision window" that the operator must look through. The width is similar to the spaces found in a conventional three rail upright. This also leaves room to use twin lift cylinders to lift the load engaging structure, the "carriage" and remove the normal single cylinder mounted in the center. Removing the center cylinder allows the carriage to extend backward between the front pair of rails, contributing to the reduction in load center. This is especially significant because it allows the operator to "sight down" the carpet pole to align the pole with the carpet to be handled.


A rotary valve for use in the release of a molten solid from a vessel comprises a valve member having a passage, inlets to the passage being present in the head of the member. The valve member mates with a wall of a seating member, the wall having a taller first section and a lower second section selected to close off or open the inlets, respectively. The wall portions are shaped relative to the surfaces of the member to avoid metal freezing and the parts sticking. The passage includes ribs to cause the stream to emerge with parallel sides.

This invention relates to the casting of molten metal and in particular to vessels for molten solids, e.g. molten metal, and to outlets for said vessels.
Problems occur when molten solids are poured through an outlet from a vessel, for example when pouring molten metal. In a foundry, it is known to fit an outlet through the floor of a vessel for molten metal, e.g. a foundry ladle, and to provide a so-called stopper rod above the vessel. The rod is lowered or raised to close or open the outlet. The rod comprises a metal shaft surrounded by a refractory sleeve. This arrangement has disadvantages. For example, the rod becomes distorted in use; if it is used as a throttle, the stream of metal breaks up affecting the quality of the casting; and there is a relatively long turn around period when changing the refractory sleeve of the stopper rod.
An alternative device is a so-called sliding gate valve. This is mounted externally below the bottom outlet and is used on bulk steel ladles where the liquid metal is discharged in a few pours. In the foundry, however, the outlet is opened and closed a greater number of times and there can be long intervals between one opening and the next. When the sliding gate valve is closed, a slug of metal forms in the outlet above the closed valve and is unable to circulate, even though it is communication with the bulk of the molten metal, and the slug tends to freeze if the time between successive pours is too great. This causes metal to freeze on the sliding gate valve which is thus not suitable for use with foundry ladles. The sliding gate valve is also not without problems in relation to liquid steel which is particularly prone to this "freezing-off" and there is thus a serious risk of valve blockage.
It has been realised that there should be advantages in having a rotary valve mechanism instead of a stopper rod system or a sliding gate valve system. The mechanism comprises a valve in a seating therefor in the vessel outlet. A passage is present in the valve member which has inlets in the head portion thereof. A drive mechanism is present outside the vessel and used to rotate the valve member with respect to the seating member therefor, the seating member being shaped so that when in one position the inlet is closed off and in another open. Such a system is disclosed in WO88/05355 published in July 1988; in GB-A-2226263 published in June 1990; and in WO 90/14907 published in December 1990. More specifically, GB-A-2226263 discloses an outlet comprising a rotary valve member and a seating therefor, the valve member having at least one passage for conducting molten solid from inside to outside the vessel, the valve member sealing with a wall of the seating member, the wall having a first section sufficiently high that when the valve member is rotated to align an inlet end of the passage therewith the passage is closed by the first section, the wall having a second section of less height so that if the valve member is rotated to align the inlet end of the passage therewith, the inlet end is open. The outlet is normally installed so that the top of the second section of the wall is level with the inside surface of the floor of the vessel. The first section does not extend round the periphery of the wall significantly further than necessary to close the outlet. The majority of the valve member is therefore exposed so that, in contrast to the conditions when a sliding gate valve is closed, the molten metal is able to circulate around the closed valve member and there is no slug of trapped metal liable to freeze between pours.
In each of these prior disclosures, insufficient attention has been paid to the practical problems of operating such a rotary valve mechanism. It has now been discovered that in order to reliably and repeatedly rotate the valve member it is necessary to shape the sealing faces as described herein and arrange the valve so that there are no dead zones wherein molten solid can be trapped; and preferably also shape the exit portion of the passage so that the stream of molten solid emerges in a predetermined shade.
In one aspect the invention provides an outlet for a vessel containing molten solid, the outlet comprising a rotary valve member and a seating member therefor, the valve member having a passage to conduct molten solid from inside to outside the vessel, the valve member sealing with a wall of the seating member, the wall having a first section sufficiently high so that when the valve member is rotated to align an inlet end of the passage therewith the inlet end is closed by the first section, the wall having a second section of relatively reduced height so that when the valve member is rotated to align an inlet end of the passage therewith the inlet end is open to allow molten solid to pass into and along the passage characterised in that the first section of the wall provides upstanding side walls for the second section whereby the second section provides the base of a generally open channel cross-sectional shape so that molten solid can pass freely in the region of the second section when the inlet is closed, and in that the opposite surfaces of the valve member and the wall of the sealing member which mate are convex in a plane including the axis of rotation of the valve member to reduce sticking in use.
Thus, because the first section provides upstanding side walls for the second section which defines the base of a channel of generally open cross-sectional shape, i.e. no roof is present, there is reduced risk of creating a dead zone in which molten solid can settle to solidify. Preferably, the sidewalls of the second section lie along planes which diverge outwardly away from the valve member to avoid a restriction of the flow of molten solid and to discourage any bridging which might otherwise lead to a solidification of the molten solid. Furthermore, in the known outlets the valve member and the seating member have conical surfaces which mate to form a seal. In use the valve member tends to stick leading to the need for large forces to rotate it, which leads to wear. However, in accordance with the present invention, the surfaces are convex in a plane including the axis of rotation of the valve member. This prevents the jamming experienced with conical members reducing the force required to rotate the valve member and generally decreasing wear and thus increasing robustness. Also, if the sealing surfaces are hemispherical the same benefits accrue and the valve assembly can tolerate slight misalignments of the refractory parts. This will be of considerable benefit in industries where unskilled labour is employed, e.g. in the steel and iron industries.
In accordance with an alternative or additional aspect of the invention, the outlet has a branched passage which has a plurality of outlet ends spaced from each other so as to be aligned with the second section of the wall in different rotational positions of the valve member, the inlet ends communicating with a common outlet end of the passage. If, in use the valve member is always rotated in the same direction, both to open and close the passage, each of the inlet ends will be used in turn, so reducing the wear and tear on each and increasing the life of the outlet.
The dimensions of the sections depend on the number of inlets and whether they are to be used singly or together.. Where there is a single inlet and a single second section, the first section preferably comprises from about 19% to about 81% of the length of the wall. Where there are two inlets and two second sections the first section preferably comprises from about 38% to about 62% of the length of the wall. Where there are two inlets and a single second section so that the inlets are used individually preferably the first section comprises from about 69% to about 81% of the length of the wall. The number of inlets may exceed two. The dimensions given are preferred in the case of casting articles of steel in a foundry, and other values may be appropriate when the molten solid is different, e.g. or another metal such as iron, or steel when processed in a steelmill or a
A suitable material from which to form an outlet intended for a metallurgical vessel, is graphitised alumina and the valve member and seating member are preferably made by isostatic pressing. Although a preferred embodiment of the invention is utilised in a vessel for molten metal, the invention can be applied to a vessel for any molten solid which is liable to freeze blocking the outlet.
It is a much preferred feature of the invention that the flow of molten metal emerging from the down pipe be coherent, i.e. having substantially parallel sides, irrespective of the extent of opening of the inlet. To ensure this, in a further feature of the invention, means to control the shape of the stream are present in the passage. Most preferably the means comprises elongate generally parallel straight sided ribs, radially spaced about the passage. Preferably at least two such ribs are present.
The invention also extends to a vessel for molten solids having a floor having an opening containing an outlet as defined in this invention, the top of the second section of the wall of the outlet being approximately level with that of the surface of the floor inside the vessel.


A universal hitch adapter system includes a universal hitch adapter with at least one force sensor operable to measure push-and-pull forces and coupled to a) one of a front end and a rear end of an aircraft tractor and b) an aircraft tow bar coupled to a nose gear of an aircraft. The system also including a memory; a user input interface operable to receive a user's selection of one of a plurality of aircrafts stored in the memory and a user's input associated with one of a shear pin; a processor operably configured to determine at least one shear pin breaking force threshold for each of the plurality of aircrafts based on the user's input; and an indicator operable to emit an alert as a result of the force sensor measuring a force that meets or exceeds the at least one shear pin breaking force threshold.

It is known that tractors are often used to tow aircraft on the ground from one location to another. Such tractors typically use a tow bar with a coupler on one end and a tow bar head on the other end. The coupler couples to the hitch of the tractor and the tow bar head couples to a nose gear of the aircraft to be towed. Aircraft nose gears have a certain threshold force value that cannot be exceeded during the push and pull phase of a tractor maneuvering the towed aircraft on the ground. Exceeding this threshold force value can damage the nose gear/landing to the extent that it can malfunction after take-off, or render it unable to cycle correctly making it very dangerous for operation. If such damage to the nose gear is detected, the nose gear is required to be tested and certified prior to flight departure. This repair of the nose gear and testing for certification prior to any use in flight represents a significant monetary expense, including the time expended that the aircraft is unable for commercial use. If the damage to the nose gear goes undetected, it can result in serious problems during flight/take-off/landing that could, unfortunately, result in a crash or other dangerous situations. Accordingly, it is very important for aircraft tractors to tow aircrafts without exerting forces that would damage or wear away at the nose gear or nose gear shear pins. Unfortunately, prior art methods and devices are lacking.
Use of aircraft tractors to move aircrafts, rather than the aircraft's own engines, became desirable in order to save on fuel. Initially, tractor speeds during towing efforts had been previously restricted to very slow speeds (i.e., less than 10 miles/hour). It became desirable to increase such speeds, even for fully loaded aircrafts, to increase the viability of taxiing fully loaded aircrafts by tractor, rather than the aircraft's engine, for additional fuel saving. However, this would increase forces between the aircraft and the tractor, which could result in too much force being transmitted to the nose gear. In addition, such higher speeds would increase the risks associated with jack-knifing. Also, it was not desirable to leave the control over the aircraft solely in the hands of the tractor driver, who may not have been as skilled and responsible as a pilot.
One solution was developed in U.S. Pat. No. 4,113,041 (Birkeholm), which included a sensing element within an aircraft tow bar that measures the traction and pressure forces transmitted between the tractor and the aircraft and a control unit that automatically adjusted the traction-effect of the tractor, as well as, the braking of the aircraft, to keep the tow bar forces within a predetermined permissible level. For safety, the Birkeholm system included an emergency release system that separated the aircraft from the tractor in response to the tow bar forces exceeding a predetermined range. Unfortunately, there are some major drawbacks to this solution. By being integrated with the aircraft and the tow bar, the Birkholm system was not flexible for use with other aircraft, as well as, other tow bars. In addition, some drivers and pilots are not comfortable with such automatic traction adjustment and aircraft braking controlled by an electronic control unit, which is subject to error.
In order to avoid costly damage to the nose gear by transmitting forces that are too high for the nose gear to sustain, it is also known to use a towing pin, also referred to as a shear pin, as a mechanical fuse so that such high forces can break the shear pin, rather than the nose gear. However, this solution is not perfect. In order to guarantee that a shear pin will break when the situation requires it, such as when the steering angle of the wheels on the nose gear is considerable, sheer pins are manufactured with a rather large safety margin, which leads to pins breaking frequently, and sometimes unnecessarily. In addition, even though breaking the shear pin breaks the connection between the aircraft and the tow bar (and, thereby, the tractor), which terminates the application of excessive forces to the nose gear, it is nonetheless a hazard as the aircraft may not completely come to a rest immediately after the connection is terminated, and may continue to roll on its own momentum.
One solution was developed in U.S. Pat. No. 9,108,746 (Schmidt), which disclosed a shear pin with a force sensor and an accelerometer that measured the shear pin's angle of inclination. Schmidt's shear pin also calculated a force threshold as a function of the measured force and the angular orientation of the nose gear wheels, as determined by the accelerometer, generating an alarm when the force threshold was reached or exceeded.
Unfortunately, these prior art devices and systems are specific to a particular aircraft. Such devices and systems are not adaptable and flexible so that a single instance of a device/system may be tied to the tractor and configured for interchangeable use, on-the-fly, with multiple aircrafts, multiple shear pins, and multiple tow bars.
In particular, towhead shear pins are fitted to an individual aircraft towhead and are manufactured so as to shear upon a predetermined force being met or exceeded. Such shearing of the shear pin is intended to be an alert to the tractor driver that a safe force has been exceeded and inspection, as well as, replacement of the shear pin is required. Accordingly, failure of the shear pin itself is undesirable.
Therefore, a need exists to overcome the problems with the prior art as discussed above.