Abstract:
Apparatus and methods control CMP to uniformly polish a series of wafers. Average motor current I(avg) drawn by, and related average work W(avg) performed by, motors during CMP on the wafers reliably indicate quality of a roughness polishing characteristic of a polishing surface of a polishing pad. A conditioner controller controls a rate at which the quality of the polishing surface is restored by conditioning in relation to a rate of change of the quality of the polishing surface due to the CMP. Motor current is measured and averaged over many CMP-processed wafers. The method defines a baseline range of values of average work and controls conditioning according to whether average work is within the baseline range. When the polishing surface moves at constant velocity relative to each of the wafers that are being polished, a control signal based on average motor current represents the quality of the polishing characteristic.
Abstract:
Four load cells supporting a seat or part thereof provide four signals that are added to determine the weight of the seat occupant. Each load cell has two flanged springs stressed to provide preload. The two springs operate in concert to resist side forces and moments, making the load cell responsive to both compressive and tensile forces while being substantially unresponsive to lateral forces and moments tending to cause angular misalignment between input elements. A preferred load cell has a liquid filled chamber and a pressure sensor providing an electric signal indicating the pressure in the liquid, which is related to the applied force. Preferred manufacturing methods make the cost low. A seat belt tension sensor may close a switch at a predetermined seat belt tension or may measure the seat belt tension. A preferred mounting limits side forces to the load cells.
Abstract:
A seat occupant weight sensing system includes load cells that receive the weight of a seat occupant. A microprocessor receives indication of force applied to the load cells and may also receive output from a seat belt tension sensor and/or an atmospheric pressure sensor. In a first preferred embodiment four load cells supporting a seat each have a fluid filled chamber, and a pressure sensor in each load cell provides an electric signal indicating the pressure in the fluid. The four signals are added to determine the weight of the seat occupant. In a second preferred embodiment fluid conduits connect the four fluid filled chambers to a common pressure sensor. The load cells comprise two flanged conical springs stressed to provide preload. In the preferred embodiments, a spring is part of the surface of the chamber that confines the fluid. The two springs operate in concert to resist side forces and moments. The load cell is responsive to both compressive and tensile forces while being substantially unaffected by lateral forces and moments tending to cause angular misalignment. The seat belt tension sensor enables distinction between apparent weight caused by force applied by a seat belt to a child seat and the actual weight of a person. A first seat belt tension sensor comprises a switch that closes at a predetermined seat belt tension. A second seat belt tension sensor measures seat belt tension.
Abstract:
A system for determining the weight of the occupant of a vehicle seat includes a hinge near the forward edge of the seat and a force sensor responsive to downward force at a point well to the rear of the hinge thereby indicating torque about the hinge. The system includes a microprocessor connected for receiving the output of the force sensor. The microprocessor may also receive outputs from an accelerometer responsive to vertical accelerations, a seat back recline angle sensor, a seat track position sensor, a seat belt tension sensor and an atmospheric pressure sensor. In a first embodiment the microprocessor determines the weight of the seat occupant from the outputs of the force sensor and the seat back recline sensor. In a second embodiment the microprocessor determines the weight of the seat occupant from the outputs of the force sensor, the seat back recline sensor and the seat track position sensor. A force sensor comprises a compressible bottle with a Belleville spring thereby being responsive to both compression and tension while resisting lateral forces and being insensitive to angular misalignment and temperature fluctuations. The microprocessor may use the accelerometer or the seat belt tension indicator or the two in combination to establish whether the force being sensed derives from seat belt tension applied to a child seat or from the weight of a person.
Abstract:
A combined heat and electricity generating unit is suitable for use in class 8 trucks and the like. When it is operating it provides heat for keeping the engine and cabin warm and electricity for use by the electricity consuming devices in the cabin. It is a closed cycle system that includes a radial inlet turbine driven by a low pressure vaporized and superheated working fluid, an oil fired heater for vaporizing the working fluid, a pump for pumping condensed working fluid, a heat exchanger for heating engine coolant with heat from the condensing working fluid and an electric generator for converting energy produced by the turbine to electricity.
Abstract:
A force sensor for sensing the weight of a vehicle seat occupant for a vehicle's occupant protection system has a pressure sensor responsive to hydraulic pressure resulting from axial force applied to the force sensor. A constant force spring in the form of a diaphragm with two flanges simultaneous functions as a seal, a constant force bias spring, an armature support resistant to radial forces and a piston for converting force to hydraulic pressure. Two studs receive applied force. An electrical insulator is sealed to the walls of a passage inside of one of the studs to provide electrical communication while sealing against liquid leakage. A pressure sensor is mounted on the electrical insulator and connected to electrical conductors in the insulator by stitch bonding. The diaphragm resists radial movement while allowing axial movement thereby making the sensor insensitive to radial forces. By being a constant force spring the diaphragm makes the sensor insensitive to temperature variations.
Abstract:
A combined heat and electricity generating unit is suitable for use in single family homes and the like. When it is operating it provides heat for heating the home and electricity for use by the electricity consuming devices in the home and the excess is available for sale to the power utility. It includes an air compressor, a fuel pump, a turbine driven by heated combustion products and an electric motor-generator for driving the fuel pump and air compressor and converting energy produced by the turbine to electricity. In an alternate embodiment the electric motor-generator is replaced by an electric motor and an electric generator. In the case where gaseous fuel is used the fuel pump may be a positive displacement gas compressor. The pressurized combustion products enable a particularly efficient and inexpensive heat exchanger. The air compressor maintains a slight vacuum in the housing thereby eliminating risk of combustion products escaping.
Abstract:
A crash sensor for automobiles of the type including a ball moving against viscous damping in a closed tube has a much smaller ball than known designs and a power transistor to switch power in the firing circuit. A resistance sensing circuit enables the crash sensor to monitor the firing circuit and indicate a change in the resistance of the firing circuit. In two embodiments simple message patterns allow communication of diagnostic information through existing wiring. A latching circuit maintains the switch in its closed state after initial closing. The small size of the ball enables use of a plastic or aluminum tube. The tube may have fluted walls that form air ducts that viscously conduct much of the air displaced when the ball moves. Routing most of the air through the ducts eliminates the uncertainty in the viscous resistance resulting when all of the air flows between the ball and the inner diameter of the tube. The movable element may be a sensing mass having a nonspherical shape. Compensation for the variation of air viscosity with temperature may be obtained by varying the normal resting position of the sensing mass as a function of temperature or by varying the size of the air ducts. The small sensing mass and electronic components allow simple contacts. The combination of these elements provides a crash sensing and diagnostic system costing much less than known systems.
Abstract:
Apparatus is disclosed for subjecting a test object to a vibration test. A preferred embodiment of the apparatus uses a flat coil assembly with an arrangement of permanent magnets. The vibrator is small and light weight. Hinge structures are disclosed which permit the vibrator to be used in conjunction with a shock testing machine or with other vibrators. This vibrator design is easily adapted for use for cross-axis testing of airbag crash sensors and for one, two or three axis screening applications.
Abstract:
A dual voltage power supply is disclosed for vehicles equipped with a DC generator, a single storage battery, a low voltage load circuit including the storage battery, and a high voltage load circuit including load devices designed to be powered by voltages higher than the battery voltage. At times when higher voltage power is required a low voltage regulator that includes a high current semiconductor switch converts power at the generator output voltage to power at a lower voltage for charging the battery and supplying the low voltage load circuit. There is a single voltage mode of operation when higher voltage power is not required in which the alternator is regulated to supply power at the voltage required by the low voltage load circuit and the high current semiconductor switch is held in its closed state to directly connect the generator output with the low voltage load circuit. The low voltage regulator is a switching DC to DC voltage converter with an N channel mosfet power transistor switch controlled by an improved driver circuit. The driver circuit has a floating totem pole output and a capacitively coupled input and is assisted by a pull down circuit and current from a low current supply. An input accepts a signal controlling whether the system operates in dual or single voltage mode. One or more transient absorbing semiconductors and a circuit for rapidly decreasing rotor current limit the duration of alternator overvoltage.