Transducer testing system for low frequency vibrations
First Claim
1. A transducer testing system having vibrating means for vibrating a transducer that translates mechanical energy to electrical energy and measuring means for measuring a response of said transducer within predetermined frequency ranges, wherein the improvement is characterized by:
- said vibrating means having an electric motor, a first output shaft, and mechanical converting means for converting low frequency shaft rotation of said first output shaft to a uniform low frequency sinusoidal excitation of said transducer;
said vibrating means further having a gearbox that converts shaft rotation of a second shaft of said electric motor at a first frequency to shaft rotation of said first output shaft at a second frequency; and
said transducer testing system further comprising synchronization means for providing a synchronization signal at a third frequency that corresponds to said second frequency of said first output shaft, wherein said measuring means is responsive to said synchronization signal.
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Accused Products
Abstract
A transducer testing system for low frequency vibrations incorporates an electric motor/gearbox assembly 16 with an output shaft 18 and mechanical means for converting low frequency shaft rotation of the output shaft 18 to uniform low frequency sinusoidal excitation of an accelerometer 10. Simultaneously, a data processing unit 14 measures the response of the accelerometer 10 to the uniform low frequency excitation within predetermined frequency ranges. The data processing unit 14 then compares the measured response with predetermined accelerometer response limits to ascertain whether the accelerometer 10 is functional. The transducer testing system overcomes the limitations of electrodynamic testers to provide a means for accurately testing the low frequency response of the accelerometer 10.
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Citations
48 Claims
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1. A transducer testing system having vibrating means for vibrating a transducer that translates mechanical energy to electrical energy and measuring means for measuring a response of said transducer within predetermined frequency ranges, wherein the improvement is characterized by:
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said vibrating means having an electric motor, a first output shaft, and mechanical converting means for converting low frequency shaft rotation of said first output shaft to a uniform low frequency sinusoidal excitation of said transducer; said vibrating means further having a gearbox that converts shaft rotation of a second shaft of said electric motor at a first frequency to shaft rotation of said first output shaft at a second frequency; and said transducer testing system further comprising synchronization means for providing a synchronization signal at a third frequency that corresponds to said second frequency of said first output shaft, wherein said measuring means is responsive to said synchronization signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A transducer testing system having vibrating means for vibrating a transducer that translates mechanical energy to electrical energy and measuring means for measuring a response of said transducer within predetermined frequency ranges, wherein the improvement is characterized by:
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said vibrating means having an electric motor, a first output shaft, and mechanical converting means for converting low frequency shaft rotation of said first output shaft to a uniform low frequency sinusoidal excitation of said transducer; said mechanical converting means including an eccentric hub affixed to said first output shaft, said eccentric hub having an outer first cylindrical surface; an annular beating having an inner race and an outer race, said inner race secured to said first cylindrical surface; a piston having a second cylindrical surface, first and second end surfaces, biasing means for biasing said first end surface to said outer race of said annular bearing, and means for fastening said transducer to said second end surface in alignment with a sliding motion of said piston; and a piston beating block having an inner sleeve which slidably mates to said second cylindrical surface to guide said sliding motion of said piston. - View Dependent Claims (10)
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11. A transducer testing system comprising:
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an electric motor and gearbox assembly with an output shaft; an eccentric hub affixed to said output shaft, said eccentric hub having an outer first cylindrical surface; an annular bearing having an inner race and an outer race, said inner race secured to said first cylindrical surface; a piston having a second cylindrical surface, first and second end surfaces, a notch in said first end surface that engages said outer race of said bearing, a spring clip that fits securely in a groove in said second cylindrical surface, a spring surrounding said second cylindrical surface mounted between said spring clip and said piston bearing block to bias said notch to said outer race of said annular bearing, and means for fastening said transducer to said second end surface in alignment with a sliding motion of said piston; a piston bearing block having an inner sleeve which slidably mates to said second cylindrical surface of said piston to guide said sliding motion of said piston and vibrate said transducer; and measuring means for measuring a response of said transducer to said vibration within predetermined frequency ranges, said measuring means having first circuit means for performing Fast Fourier Transforms to the response of said transducer. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A vibrator for exciting a transducer that translates mechanical energy to electrical energy at a uniform low frequency sinusoidal excitation, the vibrator comprising:
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an electric motor; a first output shaft; and mechanical converting means for converting low frequency shaft rotation of said first output shaft to a uniform low frequency sinusoidal excitation of said transducer, wherein mechanical convening means comprises an eccentric hub affixed to said first output shaft, said eccentric hub having an outer first cylindrical surface, an annular beating having an inner race and an outer race, said inner race secured to said first cylindrical surface, a piston having a second cylindrical surface, first and second end surfaces, biasing means for biasing said first end surface to said outer race of said annular beating, and means for fastening said transducer to said second end surface in alignment with a sliding motion of said piston, and a piston bearing block having an inner sleeve which slidably mates to said second cylindrical surface to guide said sliding motion of said piston. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A vibrator for exciting a transducer that translates mechanical energy to electrical energy at a uniform low frequency sinusoidal excitation, the vibrator comprising:
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a housing; an electric motor and gearbox assembly with an output shaft; a mounting means secured to said housing for affixing said motor and gearbox assembly to said housing; an eccentric hub affixed to said output shaft, said eccentric hub having an outer first cylindrical surface; an annular bearing having an inner race and an outer race, said inner race secured to said first cylindrical surface; a piston having a second cylindrical surface, first and second end surfaces, a notch in said first end surface that engages said outer race of said bearing, a spring clip that fits securely in a groove in said second cylindrical surface, a spring surrounding said second cylindrical surface mounted between said spring clip and said piston bearing block to bias said notch to said outer race of said annular bearing, and means for fastening said transducer to said second end surface in alignment with a sliding motion of said piston; and a piston bearing block having an inner sleeve which slidably mates to said second cylindrical surface of said piston to guide said sliding motion of said piston and vibrate said transducer, said piston bearing block affixed to said mounting means. - View Dependent Claims (30, 31, 32)
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33. A method of operating a transducer tester,
said transducer tester having vibrating means for sinusoidally exciting a transducer that translates mechanical energy to electrical energy, said transducer tester also having measuring means for measuring and storing a response of said transducer within predetermined frequency ranges, said vibrating means having an electric motor, a first output shaft, and mechanical converting means for converting low frequency shaft rotation of said first output shaft to a uniform low frequency sinusoidal excitation of said transducer, said transducer tester further having comparing means for comparing the response of said transducer with predetermined limits, the method comprising the steps of: -
sinusoidally exciting said transducer at a low frequency with said vibrating means; simultaneously measuring and storing the response of said transducer to said excitation within said predetermined frequency ranges with said measuring means; and comparing the response of said transducer with said predetermined limits in order to ascertain whether said transducer is functional. - View Dependent Claims (34, 35)
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36. A method of operating a transducer tester,
said transducer tester having vibrating means for sinusoidally exciting a transducer that translates mechanical energy to electrical energy, said transducer tester also having measuring means for measuring and storing a response of said transducer within predetermined frequency ranges, said vibrating means having an electric motor, a first output shaft, mechanical converting means for converting low frequency shaft rotation of said first output shaft to a uniform low first frequency sinusoidal excitation of said transducer, and a synchronization means for providing a synchronization signal at a second frequency that corresponds to said first frequency, said transducer tester further having comparing means for comparing the response of said transducer with predetermined limits, the method comprising the steps of: -
sinusoidally exciting said transducer at said first frequency and producing said synchronization signal at said second frequency with said vibrating means; simultaneously measuring and storing the response of said transducer to said excitation within said predetermined frequency ranges with said measuring means, said predetermined frequency ranges dependent upon said second frequency of said synchronization signal; and comparing the response of said transducer with said predetermined limits in order to ascertain whether said transducer is functional. - View Dependent Claims (37, 38)
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39. A method of operating a transducer tester,
said transducer tester having vibrating means for sinusoidally exciting a transducer that translates mechanical energy to electrical energy, said transducer tester also having measuring means for measuring and storing a response of said transducer within predetermined frequency ranges, said vibrating means having an electric motor, a first output shaft, mechanical converting means for converting low frequency shaft rotation of said first output shaft to a uniform low first frequency sinusoidal excitation of said transducer, and a synchronization means for providing a synchronization signal at a second frequency that corresponds to said first frequency, said transducer tester further having a means for computing an average of the response of said transducer during each cycle of said synchronization signal and subtracting said computed average from each stored response, the method comprising the steps of: -
sinusoidally exciting said transducer at said first frequency and producing said synchronization signal at said second frequency with said vibrating means; simultaneously measuring and storing the response of said transducer to said excitation within said predetermined frequency ranges with said measuring means, said predetermined frequency ranges dependent .upon said second frequency of said synchronization signal; and computing said average of the response of said transducer during each cycle of said synchronization signal and then subtracting said computed average from each stored response in order to eliminate harmonic components from the response of said transducer. - View Dependent Claims (40)
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41. A transducer tester comprising
vibrating means for sinusoidally exciting a transducer that translates mechanical energy to electrical energy, said vibrating means having an electric motor, a first output shaft, and mechanical converting means for converting low frequency shaft rotation of said first output shaft to a uniform low frequency sinusoidal excitation of said transducer; -
measuring means for measuring and storing a response of said transducer within predetermined frequency ranges; and comparing means for comparing the response of said transducer with predetermined limits to thereby ascertain whether said transducer is functional. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48)
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Specification