Inductive proximity sensor for detecting ferromagnetic, non-permeable or magnet targets
First Claim
1. A proximity sensor, comprising:
- a member having a top surface, a bottom surface, and a side surface having a width between the top and the bottom surfaces of the member, wherein the top surface is generally planar, and wherein the member defines a cavity that extends into the member from the top surface, wherein the cavity is in the shape of an annular groove having an outer wall formed by the side surface of the member and a base wall formed by the bottom surface of the member, wherein the outer wall and the base wall have a thickness less than or equal to 0.06 inches; and
a sensing coil positioned in the cavity for allowing magnetic flux communication between the sensing coil and the core.
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Accused Products
Abstract
A core of a proximity sensor is made of a highly permeable metal and is shaped and sized to operate as a saturable core proximity sensor, a variable reluctance proximity sensor, and an eddy current proximity sensor. The core has a cross-sectional shape including a head portion, two legs extending from the head portion, and two foot portions (feet) extending from the two legs. The head portion forms a substantially planar section along the upper surface and is perpendicular to the sectional direction created by the two legs. The sectional direction of the two legs are perpendicular to the sectional direction of the two feet. The two feet are in a common plane along the bottom surface. Both foot portions are also parallel to the head portion. The cross-sectional shape of the core may further comprises two tail portions (tails), wherein each tail extends from one of the two foot portions in a direction toward the upper surface.
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Citations
31 Claims
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1. A proximity sensor, comprising:
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a member having a top surface, a bottom surface, and a side surface having a width between the top and the bottom surfaces of the member, wherein the top surface is generally planar, and wherein the member defines a cavity that extends into the member from the top surface, wherein the cavity is in the shape of an annular groove having an outer wall formed by the side surface of the member and a base wall formed by the bottom surface of the member, wherein the outer wall and the base wall have a thickness less than or equal to 0.06 inches; and
a sensing coil positioned in the cavity for allowing magnetic flux communication between the sensing coil and the core. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A proximity sensor, comprising:
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a core formed of a permeable material, the core having a generally planar top surface, a bottom, and a side surface having a depth between the top and the bottom surface of the core, the core defining an annular groove which extends into the core from the top surface of the core, wherein the annular groove comprises an outer wall formed by the side surface of the core and a base wall formed by the bottom surface of the core, wherein the outer wall and the base wall have a thickness less than or equal to 0.06 inches;
a sensing coil positioned in the groove of the core; and
an oscillator circuit coupled to the sensing coil for energizing the sensing coil to define a sensing region in relation to the sensing coil, wherein the oscillator circuit is configured to sense a ferromagnetic, non-permeable or magnetic object in the sensing region based on an inductance measured from the sensing coil. - View Dependent Claims (8, 9, 10)
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11. A method for detecting the presence of a magnetic object which comprises:
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providing a core formed of a permeable material, the core having a generally planar top surface, a bottom, and a side surface having a depth between the top and the bottom surface of the core, the core defining an annular groove which extends into the core from the top surface of the core, wherein the annular groove comprises an outer wall formed by the side surface of the core and a base wall formed by the bottom surface of the core, wherein the outer wall and the base wall have a thickness less than or equal to 0.06 inches;
providing at least one sensing coil positioned around the groove of the core; and
measuring the impedance over the sensing coil, and if the impedance varies greater than a predetermined value, generating a signal to indicate the presence of the magnetic object. - View Dependent Claims (12, 13)
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14. A method for detecting the presence of a ferromagnetic object which comprises:
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providing a core formed of a permeable material, the core having a generally planar top surface, a bottom, and a side surface having a depth between the top and the bottom surface of the core, the core defining an annular groove which extends into the core from the top surface of the core, wherein the annular groove comprises an outer wall formed by the side surface of the core and a base wall formed by the bottom surface of the core, wherein the outer wall and the base wall have a thickness less than or equal to 0.06 inches;
providing at least one sensing coil positioned around the groove of the core;
supplying an electronic signal to the sensing coil; and
measuring the inductance over the sensing coil, and if the inductance varies greater than a predetermined value, generating a signal to indicate the presence of the ferromagnetic object. - View Dependent Claims (15, 16)
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17. A method for detecting the presence of a conductive object which comprises:
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providing a core formed of a permeable material, the core having a generally planar top surface, a bottom, and a side surface having a width between the top and the bottom surface of the core, the core defining an annular groove which extends into the core from the top surface of the core, wherein the annular groove comprises an outer wall formed by the side surface of the core and a base wall formed by the bottom surface of the core, wherein the outer wall and the base wall have a thickness less than or equal to 0.06 inches;
providing at least one sensing coil positioned around the groove of the core;
supplying an electronic signal to the sensing coil; and
measuring the inductance over the sensing coil, and if the inductance varies greater than a predetermined value, generating a signal to indicate the presence of the conductive object. - View Dependent Claims (18, 19)
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20. A proximity sensor, comprising:
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a core having a central part and two legs attached to the central part, wherein the two legs are positioned on opposite sides of the central part;
a first sensing coil operatively associated with the core such that the core influences an electrical signal in the first sensing coil; and
a circuit coupled to the first sensing coil, for sensing an object located in a sensing region adjacent to the core, wherein the core and circuit are configured and arranged to detect the presence of ferromagnetic, non-permeable and magnet targets. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification