Apparatus and method for measuring movement
First Claim
Patent Images
1. A measuring appartus comprising:
- a hollow vessel having an inner surface with a predetermined cross-sectional configuration;
a one piece solid mass comprising a permanent magnet and having an outer surface with a cross-sectional configuration substantially the same as said cross-sectional configuration of said hollow vessel and located within said hollow vessel;
said cross-sectional configuration of said one piece solid mass having an area slightly less than the area of said cross-sectional configuration of said hollow vessel;
friction reducing means comprising a coating of a friction reducing material completely covering said outer surface of said one piece solid mass and united thereto for movement therewith and said coating being in complete surface contact with adjacent portions of said inner surface of said hollow vessel for permitting substantially friction free movement of said one piece solid mass in said hollow vessel;
resistance reducing means for reducing any resistance to movement of said one piece solid mass in said hollow vessel comprising atmospheric equalization means exterior of said hollow vessel for providing atmospheric equalization from one side of said one piece solid mass in said hollow vessel to the other side of said one piece solid mass in said hollow vessel;
electrical means for acting on said one piece solid mass to locate said one piece solid mass at a null position in said hollow cylinder;
detecting means for detecting any relative movement between said hollow vessel and said one piece solid mass in response to a force applied to said hollow vessel so that said one piece solid mass is not located at said null position; and
measuring means for measuring said relative movement and for producing and exerting an equal force on said one piece solid mass in a direction opposite to the direction of said relative movement.
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Abstract
An accelerometer comprising a ferrofluid coated permanent magnet as a proof mass mounted for substantially friction-free movement in a hollow vessel on which vessel are mounted three coils that are used with an electrical circuit to detect and measure movement of the proof mass in response to an outside force and to return the proof mass to a null position.
39 Citations
15 Claims
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1. A measuring appartus comprising:
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a hollow vessel having an inner surface with a predetermined cross-sectional configuration; a one piece solid mass comprising a permanent magnet and having an outer surface with a cross-sectional configuration substantially the same as said cross-sectional configuration of said hollow vessel and located within said hollow vessel; said cross-sectional configuration of said one piece solid mass having an area slightly less than the area of said cross-sectional configuration of said hollow vessel; friction reducing means comprising a coating of a friction reducing material completely covering said outer surface of said one piece solid mass and united thereto for movement therewith and said coating being in complete surface contact with adjacent portions of said inner surface of said hollow vessel for permitting substantially friction free movement of said one piece solid mass in said hollow vessel; resistance reducing means for reducing any resistance to movement of said one piece solid mass in said hollow vessel comprising atmospheric equalization means exterior of said hollow vessel for providing atmospheric equalization from one side of said one piece solid mass in said hollow vessel to the other side of said one piece solid mass in said hollow vessel; electrical means for acting on said one piece solid mass to locate said one piece solid mass at a null position in said hollow cylinder; detecting means for detecting any relative movement between said hollow vessel and said one piece solid mass in response to a force applied to said hollow vessel so that said one piece solid mass is not located at said null position; and measuring means for measuring said relative movement and for producing and exerting an equal force on said one piece solid mass in a direction opposite to the direction of said relative movement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A measuring apparatus comprising:
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a hollow vessel having an inner surface with a predetermined cross-sectional configuration; a one piece solid mass comprising a permanent magnet and having an outer surface with a cross-sectional configuration substantially the same as said cross-sectional configuration of said hollow vessel and located within said hollow vessel; said cross-sectional configuration of said one piece solid mass having an area slightly less than the area of said cross-sectional configuration of said hollow vessel; friction reducing means comprising a coating of a ferrofluid for permitting substantially friction free movement of said one piece solid mass in said hollow vessel; resistance reducing means for reducing any resistance to movement of said one piece solid mass in said hollow vessel; at least one portion of said hollow vessel extending in a liner direction; said one piece solid mass having a linear extent substantially less than the linear extent of said one portion of said hollow vessel; electrical means comprising an inductive control coil surrounding a central portion of said one portion of said hollow vessel for acting on said one piece solid mass to locate said one piece solid mass at a null position in said hollow cylinder; detecting means for detecting any relative movement between said hollow vessel and said one piece solid mass in response to a force applied to said hollow vessel so that said one piece solid mass is not located at said null position comprising; a first inductive sensing coil surrounding a portion of said hollow vessel adjacent to one side of said inductive control coil; and a second inductive sensing coil surrounding a portion of said hollow vessel adjacent to the other side of said inductive control coil; measuring means for measuring said relative movement and for producing and exerting an equal force on said one piece solid mass in a direction opposite to the direction of said relative movement; a permeable flux concentrator sandwiched between said control coil and said central portion; the inner surface of said one portion of said hollow vessel is cylindrical; the outer surface of said one piece solid mass is cylindrical; the linear extend of said one piece solid mass is substantially equal to the linear extent of said inductive control coil; and said one piece solid mass comprises a hollow cylinder to provide said resistance reducing means.
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15. A measuring apparatus comprising:
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a hollow vessel having an inner surface with a predetermined cross-sectional configuration; a one piece solid mass comprising a premanent magnet and having an outer surface with a cross-sectional configuration substantially the same as said cross-sectional configuration of said hollow vessel and located within said hollow vessel; said cross-sectional configuration of said one piece solid mass having an area slightly less than the area of said cross-sectional configuration of said hollow vessel; friction reducing means comprising a coating of a friction reducing material completely covering said outer surface of said one piece solid mass for movement therewith and in substantially complete surface contact with adjacent portions of said inner surface of said hollow vessel for permitting substantially friction free movement of said one piece solid mass in said hollow vessel; resistance reducing means for reducing any resistance to movement of said one piece solid mass in said hollow vessel comprising a substantially complete vacuum in said hollow vessel; electrical means for acting on said one piece solid mass to locate said one piece solid mass at a null position in said hollow cylinder; detecting means for detecting any relative movement between said hollow vessel and said one piece solid mass in response to a force applied to said hollow vessel so that said one piece solid mass is not located at said null position; and measuring means for measuring said relative movement and for producing and exerting an equal force on said one piece solid mass in a direction opposite to the direction of said relative movement.
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Specification