Non-contacting shaft rpm and direction of rotation measurement system

Claim 2

A noN-contacting sensing system for measuring the speed and direction of rotation of a driven shaft comprising a reference wheel mounted on the shaft, an exciter wheel adapted to be rotatably driven and mounted in the plane of said reference wheel, said wheels being spaced from each other to form an air gap between adjacent peripheral points, first sensing means disposed across said air gap for sensing relative motion between said wheels and developing a first signal related to the algebraic sum of the speed of the reference wheel and the exciter wheel, second sensing means disposed adjacent said exciter wheel for developing a second signal related to the speed of the exciter wheel and means for transforming said first and said second signals into a single output signal indicative of the speed and direction of rotation of the driven shaft.

Claim 3

A non-contacting sensing system as set forth in claim 1 further including a zero center indicating instrument connected to and adapted to be driven by said single output signal.

Claim 4

A non-contacting sensing system as set forth in claim 1 wherein said first sensing means and said second sensing means comprise magnetic pickup elements.

Claim 5

A non-contacting sensing system as set forth in claim 3, wherein said reference wheel and said exciter wheel are toothed, said first sensing means and said second sensing means having magnetic elements cooperatively disposed with the teeth of said wheels.

Claim 6

A non-contacting sensing system as set forth in claim 3, wherein each of said wheels are axially relieved and said first sensing means includes elements disposed on opposite sides of the air gap formed between adjacent peripheral points of the wheels and within the axial relieved portions of the wheels.

Claim 7

A non-contacting sensing system as set forth in claim 5, wherein said first sensing means is a magnetic element including a magnetic core comprising end portions and an intermediate magnet for establishing a quiescent flux across said air gap, opposite end portions being disposed on opposite sides of said air gap and within the axial relieved portions of the wheels.

Claim 8

A non-contacting sensing system as set forth in claim 1, wherein said exciter wheel and at least one of said sensing means is disposed entirely within a sealed housing.

Claim 9

A non-contacting sensing system as set forth in claim 1, wherein said exciter wheel and at least said second sensing means is disposed entirely within a sealed housing.

Claim 10

A non-contacting sensing system as set forth in claim 1, wherein said means for transforming said first and said second signal includes a first channel adapted to receive said first signal and transform said first signal into a D.C. voltage, a second channel adapted to receive said second signal and transform said second signal into a D.C. voltage and a D.C. comparator adapted to receive said D.C. voltages and provide a single D.C. output voltage proportional to the difference between the D.C. voltages.

Claim 11

A non-contacting sensing system as set forth in claim 1 further including a zero center indicating instrument connected to be driven by said single D.C. output voltage.

Claim 12

A non-contacting sensing system as set forth in claim 9 including a sealed dustproof housing for said exciter wheel and substantially the entire portion of the elements forming said first and said second sensing means.

Claim 13

A sensing system for measuring the speed and direction of rotation of a driven shaft comprising a reference wheel mounted on the shaft, a drive shaft, an exciter wheel mounted on the drive shaft and in the plane of the reference wheel, means for rotatably driving the drive shaft, said wheels being spaced such that their peripheries pass in close proximity to each other at one point, first pickup assembly means disposed about said one point and out of physical contact with said wheels for sensing the relative motion between said wheels and developing a signal relative to the algebraic sum of the speed of the wheels, a second non-contacting pickup assembly means disposed adjacent the periphery of the exciter wheel for developing a signal related to the speed of the exciter wheel and means for transforming said first and said second signals into a single output signal indicative of the speed and direction of rotation of the driven shaft.

Claim 14

A sensing system for measuring the speed and direction of rotation of a driven shaft comprising a reference wheel mounted on the shaft, a drive shaft, an exciter wheel mounted on the drive shaft and in the plane of the reference wheel, means for rotatably driving the drive shaft, said wheels being spaced such that their peripheries pass in close proximity to each other at one point, first pickup assembly means disposed about said one point and out of physical contact with said wheels for sensing the relative motion between said wheels and developing a signal relative to the algebraic sum of the speed of the wheels, a second non-contacting pickup assembly means disposed adjacent the periphery of the exciter wheel for developing a signal related to the speed of the exciter wheel and means for transforming said first and said second signals into a single output signal indicative of the speed and direction of rotation of the driven shaft.

Claim 15

A sensing system as set forth in claim 12, including a dustproof sealed housing enclosing all of the elements of the system except said drive shaft, said reference wheel and a portion of said first pickup assembly means.

Claim 16

A sensing system as set forth in claim 13, wherein said means for transforming said first and said second signal includes a first channel adapted to receive said first signal and transform said first signal into a D.C. voltage, a second channel adapted to receive said second signal and transform said second signal into a D.C. voltage and a D.C. comparator adapted to receive said D.C. voltages and provide a single D.C. output voltage proportional to the difference between the D.C. voltages.

Claim 17

A sensing system as set forth in claim 14 further including a zero center indicating instrument connected to be driven by said single D.C. output voltage.

Claim 18

A non-contacting sensing system as set forth in claim 1 further including means for continually driving said exciter wheel.

Claim 19

A non-contacting sensing system as set forth in claim 1 further including means for driving said exciter wheel at a constant speed.