System and method for sensing the angular position of a rotatable member
First Claim
1. A system for sensing the angular position of a rotatable member, the system comprising:
- a composite rotatable member comprising a solidifiable material and a magnetically attractable particulate material dispersed throughout said solidifiable material, the rotatable member having a major body portion and at least one magnetically detectable reference point in the major body portion defined by a concentrated portion of said magnetically attractable particulate material, the reference point having a first magnetic property and the major body portion having a second magnetic property, the reference point containing a first volume percent of the magnetically attractable particulate material and the major body portion containing a second volume percent of the magnetically attractable particulate material, the first volume percent being greater than the second volume percent, the first volume percent being at least about 1.5 times to 10 times greater than the second volume percent; and
a magnetic property sensor which is fixed relative to the rotatable member;
the sensor able to detect the passage of the reference point within the rotatable member.
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Accused Products
Abstract
The present invention relates to a system and method for sensing the angular position of a rotatable member. The system and method employ the use of a composite rotatable member comprising a solidifiable material and a magnetically attractable particulate material. The rotatable member has a major body portion and at least one magnetically detectable reference point. The reference point has a first magnetic property and the major body portion has a second magnetic property, different from the first magnetic property. A magnetic property sensor is fixed relative to the rotatable member to detect the passage of the reference point within the rotatable member. The sensor produces a signal in response to the passage of the reference point. A central processing unit is provided for determining the angular position of the rotatable member in response to the signal generated by the sensor.
94 Citations
17 Claims
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1. A system for sensing the angular position of a rotatable member, the system comprising:
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a composite rotatable member comprising a solidifiable material and a magnetically attractable particulate material dispersed throughout said solidifiable material, the rotatable member having a major body portion and at least one magnetically detectable reference point in the major body portion defined by a concentrated portion of said magnetically attractable particulate material, the reference point having a first magnetic property and the major body portion having a second magnetic property, the reference point containing a first volume percent of the magnetically attractable particulate material and the major body portion containing a second volume percent of the magnetically attractable particulate material, the first volume percent being greater than the second volume percent, the first volume percent being at least about 1.5 times to 10 times greater than the second volume percent; and
a magnetic property sensor which is fixed relative to the rotatable member;
the sensor able to detect the passage of the reference point within the rotatable member. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A composite rotatable member comprising:
a solidifiable material and a magnetically attractable particulate material dispersed throughout said solidifiable material, the rotatable member having a major body portion having a first volume percent of said magnetically attractable particulate material and at least one magnetically detectable reference point in the major body portion having a second volume percent of said magnetically attractable particulate material, the reference point having a first magnetic property and the major body portion having a second magnetic property, different from the first magnetic property, and said second volume percent is at least about 1.5 times to 10 times greater than said first volume percent. - View Dependent Claims (9, 10, 11)
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12. A method for sensing the angular position of a rotatable member, the method comprising the steps of:
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providing a composite rotatable member comprising a solidifiable material and a magnetically attractable particulate material dispersed throughout the solidifiable material, the rotatable member having a major body portion and at least one magnetically detectable reference point in the major body portion defined by a concentrated portion of the magnetically attractable particulate material, the reference point having a first magnetic property and the major body portion having a second magnetic property, different from the first magnetic property, the reference point containing a first volume percent of the magnetically attractable particulate material and the major body portion containing a second volume percent of the magnetically attractable particulate material, the first volume percent being greater than the second volume percent, the first volume percent being at least about 1.5 times to 10 times greater than the second volume percent;
providing a magnetic property sensor which is fixed relative to the rotatable member;
detecting the passage of the reference point within the rotatable member and producing a signal in response to the passage of the reference point; and
providing a processor and determining the angular position at the rotatable member in response to the signal from the sensor. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification