Self-compensating position sensor
First Claim
1. A sensor for sensing the position a movable member, comprising:
- first and second spaced apart and deflectable members, the movable member being movable between said first and second deflectable members so that said first and second deflectable members are laterally deflectable by the movable member in correspondence with a movement of the movable member, such that said first and second deflectable members deflect in opposite lateral directions and an amount of lateral deflection by both deflectable members increases the further the movable member is moved in between the first and second deflectable members, said first and second deflectable members each being arranged to create a deflection-dependent effect based on movement of the movable member; and
a deflection determining device constructed and arranged to generate a signal based on the deflection-dependent effects created by deflection of said first and second deflectable members, said signal being proportional to a position of the movable member, such that a combination of the deflection-dependent effect created by deflection of said first deflectable member and the deflection-dependent effect created by deflection of said second deflectable member indicates position of said movable member.
1 Assignment
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Accused Products
Abstract
A position sensor and a method for sensing a position of a moveable member includes at least first and second deflectable members arranged so as to allow the moveable member to pass therebetween and cause the at least first and second moveable members to deflect in proportion to the position of the moveable member relative to the first and second deflectable members. In one example of the present invention, the deflectable members are cantilever-mounted members extending in generally the same direction. The amount of resultant deflection is measured by any suitable means. For example, each deflectable member may have a Wheatstone bridge provided thereon acting as a strain gauge in a known manner, such that the strain detected is proportional to the amount of deflection. In a particular example of the present invention, some of the elements of a first Wheatstone bridge are provided on the first deflectable member and some are provided on the second deflectable member. Likewise, some of the elements of a second Wheatstone bridge are provide on the first deflectable member and some are provided on the second. This desirably provides matched redundancy as well as compensation for spurious lateral movement of the moveable member.
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Citations
55 Claims
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1. A sensor for sensing the position a movable member, comprising:
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first and second spaced apart and deflectable members, the movable member being movable between said first and second deflectable members so that said first and second deflectable members are laterally deflectable by the movable member in correspondence with a movement of the movable member, such that said first and second deflectable members deflect in opposite lateral directions and an amount of lateral deflection by both deflectable members increases the further the movable member is moved in between the first and second deflectable members, said first and second deflectable members each being arranged to create a deflection-dependent effect based on movement of the movable member; and
a deflection determining device constructed and arranged to generate a signal based on the deflection-dependent effects created by deflection of said first and second deflectable members, said signal being proportional to a position of the movable member, such that a combination of the deflection-dependent effect created by deflection of said first deflectable member and the deflection-dependent effect created by deflection of said second deflectable member indicates position of said movable member. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
said first and second resistive elements of said first Wheatstone bridge are provided on a side of said first deflectable member facing the movable member;
said third and fourth resistive elements of said first Wheatstone bridge are provided on a side of said second deflectable member facing away from the movable member;
said first and second resistive elements of said second Wheatstone bridge are provided on a side of said first deflectable member facing away from the movable member; and
said third and fourth resistive elements of said second Wheatstone bridge are provide on a side of said second deflectable member facing the movable member.
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4. The sensor according to claim 3, wherein said first and second Wheatstone bridges each include:
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a voltage input electrically between said first and fourth resistive elements;
a ground electrically between said second and third resistive elements;
a first output electrically between said first and third resistive elements; and
a second output electrically between said second and fourth resistive elements.
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5. The sensor according to claim 4, said deflection determining device comprising temperature-sensitive fifth resistive elements connected to said voltage input of said first Wheatstone bridge and to said voltage input of said second Wheatstone bridge, respectively.
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6. The sensor according to claim 4, wherein at least one of said first, second, third, and fourth resistive elements of said first and second Wheatstone bridges has a resistance of 8 k ohms.
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7. The sensor according to claim 4, the deflection determining device comprising a resistive temperature detector.
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8. The sensor according to claim 1, wherein said deflection determining device comprises a converting mechanism constructed and arranged to convert said signal proportional to a position of the movable member into a position value.
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9. The sensor according to claim 1, wherein said first and second deflectable members extend on either side of an axis, the movable member being movable along the same axis.
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10. The sensor according to claim 1, wherein said deflection determining device comprises a single piezo-resistive Wheatstone bridge comprising resistive elements, some of which are provided on said first deflectable member and some of which are provided on said second deflectable member.
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11. The sensor according to claim 1, wherein said deflection determining device comprises first and second piezo-resistive Wheatstone bridges each including first and second pluralities of resistive elements, respectively, wherein said first plurality of resistive elements is provided on said first deflectable member and second plurality of resistive elements is provided on said second deflectable member.
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12. A sensor for sensing the position of a movable member, comprising:
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first and second spaced apart and deflectable members, the movable member being movable between said first and second deflectable members so that said first and second deflectable members are deflectable by the movable member in correspondence with a movement of the movable member, said first and second deflectable members each being arranged to create a deflection-dependent effect based on movement of the movable member; and
a deflection determining device constructed and arranged to generate a signal based on the deflection-dependent effects created by deflection of said first and second deflectable members, said signal being proportional to a position of the movable member, such that a combination of the deflection-dependent effect created by deflection of said first deflectable member and the deflection-dependent effect created by deflection of said second deflectable member indicates position of said movable member, wherein said first and second deflectable members are cantilever-mounted members, each having a fixed proximal end and a free distal end. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
said first and second resistive elements of said first Wheatstone bridge are provided on a side of said first deflectable member facing the movable member in said intermediate region;
said third and fourth resistive elements of said first Wheatstone bridge are provided on a side of said second deflectable member facing away from the movable member in said intermediate region;
said first and second resistive elements of said second Wheatstone bridge are provided on a side of said first deflectable member facing away from the movable member in said intermediate region; and
said third and fourth resistive elements of said second Wheatstone bridge are provide on a side of said second deflectable member facing the movable member in said intermediate region.
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21. A sensor for sensing the position of a movable member, comprising:
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first and second spaced apart and deflectable members, the movable member being movable between said first and second deflectable members so that said first and second deflectable members are deflectable by the movable member in correspondence with a movement of the movable member, said first and second deflectable members each being arranged to create a deflection-dependent effect based on movement of the movable member; and
a deflection determining device constructed and arranged to generate a signal based on the deflection-dependent effects created by deflection of said first and second deflectable members, said signal being proportional to a position of the movable member, such that a combination of the deflection-dependent effect created by deflection of said first deflectable member and the deflection-dependent effect created by deflection of said second deflectable member indicates position of said movable member, wherein the movable member is connected to a valve, such that a position of the movable member corresponds to a position of the valve.
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22. A valve position sensor comprising:
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a linearly movable member associated with a valve spool;
first and second deflectable members mounted offset from a line along which said movable member moves, said movable member being movable between said first and second deflectable members so that said first and second deflectable members are laterally deflected in opposite lateral directions in correspondence with a movement of said movable member, such that an amount of lateral deflection by both deflectable members increases the further the movable member is moved in between said first and second deflectable members;
a deflection determining device constructed and arranged to output a signal based on a deflection of said first and second deflectable members, said signal being proportional to a position of the movable member and said valve spool. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
said first and second resistive elements of said first Wheatstone bridge are provided on a side of said first deflectable member facing the movable member;
said third and fourth resistive elements of said first Wheatstone bridge are provided on a side of said second deflectable member facing away from the movable member;
said first and second resistive elements of said second Wheatstone bridge are provided on a side of said first deflectable member facing away from the movable member; and
said third and fourth resistive elements of said second Wheatstone bridge are provide on a side of said second deflectable member facing the movable member.
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25. The sensor according to claim 23, wherein said first and second Wheatstone bridges each include:
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a voltage input electrically between said first and fourth resistive elements;
a ground electrically between said second and third resistive elements;
a first output electrically between said first and third resistive elements; and
a second output electrically between said second and fourth resistive elements.
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26. The sensor according to claim 25, said deflection determining device comprising temperature-sensitive fifth resistive elements connected to said voltage input of said first Wheatstone bridge and to said voltage input of said second Wheatstone bridge, respectively.
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27. The sensor according to claim 25, wherein at least one of said first, second, third, and fourth resistive elements of said first and second Wheatstone bridges has a resistance of 8 k ohms.
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28. The sensor according to claim 25, the deflection determining device comprising a resistive temperature detector.
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29. The sensor according to claim 22, wherein said deflection determining device comprises a converting mechanism constructed and arranged to convert said signal proportional to a position of the movable member into a position value.
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30. The sensor according to claim 22, wherein the movable member is connected to a valve, such that a position of the movable member corresponds to a position of the valve.
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31. The sensor according to claim 22, wherein said first and second deflectable members extend on either side of an axis, the movable member being movable along the same axis.
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32. The sensor according to claim 22, wherein said movable member is part of the valve spool.
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33. The sensor according to claim 22, wherein said movable member is tapered.
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34. The sensor according to claim 33, wherein said movable member is conical.
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35. The sensor according to claim 22, wherein said deflection determining device comprises a single piezo-resistive Wheatstone bridge comprising resistive elements, some of which are provided on said first deflectable member and some of which are provided on said second deflectable member.
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36. The sensor according to claim 22, wherein said deflection determining device comprises first and second piezo-resistive Wheatstone bridges each including first and second pluralities of resistive elements, respectively, wherein said first plurality of resistive elements is provided on said first deflectable member and second plurality of resistive elements is provided on said second deflectable member.
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37. A valve position sensor comprising:
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a linearly movable member associated with a valve spool;
first and second deflectable members mounted offset from a line along which said movable member moves, said movable member being movable between said first and second deflectable members so as to be deflected in correspondence with a movement of said movable member;
a deflection determining device constructed and arranged to output a signal based on a deflection of said first and second deflectable members, said signal being proportional to a position of the movable member and said valve spool, wherein said first and second deflectable members are cantilever-mounted members, each having a fixed proximal end and a free distal end. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45)
said first and second resistive elements of said first Wheatstone bridge are provided on a side of said first deflectable member facing the movable member in said intermediate region;
said third and fourth resistive elements of said first Wheatstone bridge are provided on a side of said second deflectable member facing away from the movable member in said intermediate region;
said first and second resistive elements of said second Wheatstone bridge are provided on a side of said first deflectable member facing away from the movable member in said intermediate region; and
said third and fourth resistive elements of said second Wheatstone bridge are provide on a side of said second deflectable member facing the movable member in said intermediate region.
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45. The sensor according to claim 38, wherein at least one of said first and second deflectable members comprises a metal substrate having a ceramic coating.
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46. A method for detecting a position of a movable member, comprising:
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passing the movable member between first and second deflectable members so as to laterally deflect the first and second deflectable members, such that said first and second deflection members deflect in opposite lateral directions and an amount of lateral deflection by both the first and second deflectable members increases the further the movable member passes in between the deflectable members, thereby creating a deflection-dependent effect for each of the first and second deflectable members; and
determining a position of the movable member according to a combination of the deflection-dependent effect for the first deflectable member and the deflection-dependent effect for the second deflectable member. - View Dependent Claims (47, 48)
providing first and second resistive elements of a first Wheatstone bridge on a side of the first deflectable member facing the movable member;
providing third and fourth resistive elements of the first Wheatstone bridge on a side of the second deflectable member facing away from the movable member;
providing first and second resistive elements of a second Wheatstone bridge on a side of the first deflectable member facing away from the movable member;
providing third and fourth resistive elements of the second Wheatstone bridge are provide on a side of the second deflectable member facing the movable member; and
determining a deflection of the first and second deflectable members using signals generated by the first and second Wheatstone bridges; and
determining a position of the movable member based on the detected deflection of the first and second deflectable members.
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48. The method according to claim 46, wherein the first and second deflectable members comprise a metal substrate having a ceramic coating.
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49. A method for detecting a position of a movable member, comprising:
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passing the movable member between first and second deflectable members so as to deflect the first and second deflectable members, thereby creating a deflection-dependent effect for each of the first and second deflectable members; and
determining a position of the movable member according to a combination of the deflection-dependent effect for the first deflectable member and the deflection-dependent effect for the second deflectable member, wherein the first and second deflectable members are cantilever-mounted members, each having a fixed proximal end and a free distal end. - View Dependent Claims (50, 51, 52, 53, 54)
providing first and second resistive elements of a first Wheatstone bridge on a side of the first deflectable member facing the movable member in the intermediate region;
providing third and fourth resistive elements of the first Wheatstone bridge on a side of the second deflectable member facing away from the movable member in the intermediate region;
providing first and second resistive elements of a second Wheatstone bridge on a side of the first deflectable member facing away from the movable member in the intermediate region;
providing third and fourth resistive elements of the second Wheatstone bridge are provide on a side of the second deflectable member facing the movable member in the intermediate region; and
determining a deflection of the first and second deflectable members using signals generated by the first and second Wheatstone bridges; and
determining a position of the movable member based on the detected deflection of the first and second deflectable members.
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55. A position sensor comprising:
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a movable assembly including first and second spaced apart and deflectable members;
a fixed member disposed between said first and second deflectable members, said first and second deflectable members being deflectable by the fixed member in correspondence with a movement of the movable assembly relative to the fixed member, said first and second deflectable members each being arranged to create a deflection-dependent effect based on movement of the movable assembly relative to the fixed member; and
a deflection determining device constructed and arranged to output a signal based on a deflection of said first and second deflectable members, said signal being proportional to a position of the movable assembly such that a combination of the deflection-dependent effect created by deflection of said first deflectable member and the deflection-dependent effect created by deflection of said second deflectable member indicates position of the movable assembly relative to the fixed member, wherein said first and second deflectable members are cantilever-mounted members, each having a fixed proximal end and a free distal end.
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Specification