Device for measuring the velocity of a magnetically receptive object
First Claim
1. The method of measuring the speed of an object having a magnetically conductive portion where said object is moving along a predetermined path, said method comprising the steps offorming a first standing oscillating magnetic field having a first predetermined natural frequency, positioning said first standing oscillating magnetic field in said predetermined path, forming a second standing oscillating magnetic field having a second predetermined natural frequency, positioning said second standing oscillating field in said predetermined path and spaced a fixed distance from said first field, detecting a change in the frequencies of oscillation of said first and said second fields, measuring the time elapsed between said changes in frequencies of first field and said second field, and dividing said fixed distance by said measured time to calculate said speed of said object.
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Accused Products
Abstract
A device for measuring the speed of a golf club has a pair of coils spaced a given distance apart with each of the coils forming an oscillating electro-magnetic field which are positioned to interrupt the course of the head of a golf club. When a golf club head successively passes through the first and second oscillating magnetic fields, the natural frequency of the combined fields is altered. A detector circuit including a phase locked loop detects the change in frequency as the club successively pass through the two fields and the time elapsed is measured by a clock and recorded in the memory of a microprocessor which uses the information, along with the given distance between the fields to calculate the speed of the club.
25 Citations
15 Claims
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1. The method of measuring the speed of an object having a magnetically conductive portion where said object is moving along a predetermined path, said method comprising the steps of
forming a first standing oscillating magnetic field having a first predetermined natural frequency, positioning said first standing oscillating magnetic field in said predetermined path, forming a second standing oscillating magnetic field having a second predetermined natural frequency, positioning said second standing oscillating field in said predetermined path and spaced a fixed distance from said first field, detecting a change in the frequencies of oscillation of said first and said second fields, measuring the time elapsed between said changes in frequencies of first field and said second field, and dividing said fixed distance by said measured time to calculate said speed of said object.
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3. A device for measuring the speed of an object having a magnetically conductive element therein where said object moves along a predetermined path, said device comprising
first means for forming a first standing oscillating magnetic field having a first predetermined natural frequency, second means for forming a second standing oscillating magnetic field having a second predetermined natural frequency, said first means and said second means spaced a fixed distance from each other, means for driving said oscillating fields formed by said first means and said second means, detector means for detecting a change in said natural frequency of said first means and said second means, and means for measuring the time elapsed between the successive detectable changes in said natural frequencies of said first means and said second means.
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13. A device for measuring the speed of an object having a magnetically conductive element therein where said object moves along a predetermined path, said device comprising
a first coil for forming a first standing oscillating magnetic field having a first predetermined natural frequency, a second coil for forming a second standing oscillating magnetic field having a second predetermined natural frequency, said first coil and said second coil spaced a fixed distance from each other, means for driving said oscillating fields formed by said first coil and said second coil, a phased locked loop for generating a DC voltage indicative of steady state frequencies of said standing oscillating magnetic fields formed by said first coil and said second coil and for generating a spike indicative of a change in frequency of one of said first predetermined frequency and said second predetermined frequency, a comparator for identifying a spike indicative of a magnetically conductive material in one of said fields, and a clock for measuring the time elapsed between the successive detectable changes in said natural frequencies of said first coil and said second coil.
Specification