Angular acceleration sensor
First Claim
1. A device to measure angular acceleration about a predefined axis, the device comprising:
- a weight which has a shape symmetrical with respect to an axis;
transducer means for converting mechanical stress into an angular acceleration representing signal, said transducer means being attached to said weight with said axis as the center axis of a resultant assembly, and said transducer means having directional sensitivity to shear stress in a circumferential direction about said axis; and
a base member to which said assembly is fixed with said transducer means between a surface of said weight and a surface associated with said base member and sensitive to shear stress between said surfaces and such that said center axis of said assembly can be brought into agreement with said predefined axis and that at least a major portion of said wight is spaced from said base member.
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Accused Products
Abstract
A simple and shock-resistant device to measure angular acceleration about a predefined axis without using any spinning or vibrating mass. The device comprises a weight having a shape symmetrical with respect to an axis which becomes the aforementioned predefined axis, a stress transducer such as a piezoelectric element which is attached to the weight so as to have sensitivity to shear stress in a circumferential direction about the aforementioned axis, and a base member to which the assembly of the weight and the transducer is fixed such that at least a major portion of the weight is spaced from the base member. For example, the weight is a generally circular metal plate and the transducer is a ring-shaped element of a piezoelectric ceramic material having electrode films on the annular surfaces.
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Citations
18 Claims
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1. A device to measure angular acceleration about a predefined axis, the device comprising:
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a weight which has a shape symmetrical with respect to an axis; transducer means for converting mechanical stress into an angular acceleration representing signal, said transducer means being attached to said weight with said axis as the center axis of a resultant assembly, and said transducer means having directional sensitivity to shear stress in a circumferential direction about said axis; and a base member to which said assembly is fixed with said transducer means between a surface of said weight and a surface associated with said base member and sensitive to shear stress between said surfaces and such that said center axis of said assembly can be brought into agreement with said predefined axis and that at least a major portion of said wight is spaced from said base member. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A device to measure angular acceleration about a predefined axis, the device comprising:
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an electrically conductive weight which is in the form of a plate having a shape symmetrical with respect to an axis normal to said plate; a piezoelectric element which comprises a ring-shaped body of a piezoelectric ceramic material polarized in a circumferential direction and two electrode films formed on two opposite annular surfaces of said body, respectively, said piezoelectric element being attached to said weight with said axis in agreement with the center axis of said body such that said piezoelectric element has sensitivity to shear stress in a circumferential direction about said axis; and a base member to which the assembly of said weight and said piezoelectric element is fixed such that said axis can be brought into agreement with said predefined axis and that at least a major portion of said weight is spaced from said base member. - View Dependent Claims (13, 14, 15, 16, 17)
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18. An apparatus to measure angular velocity about a predefined axis, the apparatus comprising:
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an angular acceleration sensing device which comprises a weight having a shape symmetrical with respect to an axis, a transducer means for converting mechanical stress into electrical signal, said transducer means being attached to said weight with said axis as the center axis of a resultant assembly, and said transducer means having directional sensitivity to shear stress in a circumferential direction about said axis, and a base member to which said assembly is fixed with said transducer means between a surface of said weight and a surface associated with said base member and sensitive to shear stress between said surfaces and such that said center axis can be brought into agreement with said predefined axis and that at least a major portion of said weight is spaced from said base member; and an electrical circuit comprising means for integrating the output of said angular acceleration sensing device with respect to time.
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Specification