Height sensor and air spring device incorporating the same

Claim 2

A height sensor for determining the height from a surface to be measured on the basis of an optical path length from a light-emitting element to the surface to be measured, comprising: a first light-emitting element and a second light-emitting element disposed at positions spaced apart from the surface to be measured; an oscillator connected to the first and second light emitting elements for causing the first and second light emitting elements to alternately emit light; reflecting means for reflecting at least one of a beam of light emitted from said first light-emitting element and a beam of light emitted from said second light-emitting element, said reflecting means being arranged to cause respective optical paths of the beams to be brought into close proximity to each other, wherein said reflecting means is a three-dimensional mirror whose slanting surfaces are mirror surfaces, the beams emitted from said first light-emitting and said second light-emitting element being respectively reflected onto the surface to be measured by means of different slanting surfaces; a light-receiving element for receiving the beams emitted by said first light-emitting element and said second light-emitting element and reflected by the surface to be measured and for outputting a signal corresponding to a quantity of light received; a converter for converting the signal output by the light receiving element into a ratio of light output by the first and second light emitting elements; and a circuit for converting the ratio output by the converter into a signal representing the height from the surface to be measured.

Claim 3

The height sensor according to claim 1, wherein the beam from said first light-emitting element is made incident upon one of the slanting surfaces of said three-dimensional mirror via another reflecting means.

Claim 4

The height sensor according to claim 1, wherein the converter includes a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving elements and a filter for removing direct current components of an output from said logarithmic converter circuit, and the circuit is a rectifier circuit for rectifying an output of said filter.

Claim 5

The height sensor according to claim 1, wherein the converter is a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving element, and the circuit includes a pair of holding circuits for holding the outputs from said logarithmic converter circuit in corresponding relation to the beams from said first and second light-emitting elements and a subtraction circuit for calculating a difference between hold values which are held in said holding circuits.

Claim 6

A height sensor for determining the height from a surface to be measured on the basis of an optical path length from a light-emitting element to the surface to be measured, comprising: a first light-emitting element and a second light-emitting element disposed at positions spaced apart substantially a same distance from the surface to be measured; an oscillator connected to the first and second light emitting elements for causing the first and second light emitting elements to alternately emit light; reflecting means arranged to reflect and introduce to the surface to be measured at least one of a beam of light emitted from said first light-emitting element and a beam of light emitted from said second light-emitting element so as to provide an optical path difference between an optical path length from said first light-emitting element to the surface to be measured and an optical path length from said second light-emitting element to the surface to be measured; and a light-receiving element for receiving the beams emitted by said first light-emitting element and said second light-emitting element and reflected by the surface to be measured and for outputting a signal corresponding to a quantity of light received; a converter for converting the signal output by the light receiving element into a ratio of light output by the first and second light emitting elements; and a circuit for converting the ratio output by the converter into a signal representing the height from the surface to be measured.

Claim 7

A height sensor for determining the height from a surface to be measured on the basis of an optical path length from a light-emitting element to the surface to be measured, comprising: a first light-emitting element and a second light-emitting element disposed at positions spaced apart substantially a same distance from the surface to be measured; an oscillator connected to the first and second light emitting elements for causing the first and second light emitting elements to alternately emit light; reflecting means arranged to reflect and introduce to the surface to be measured at least one of a beam of light emitted from said first light-emitting element and a beam of light emitted from said second light-emitting element so as to provide an optical path difference between an optical path length from said first light-emitting element to the surface to be measured and an optical path length from said second light-emitting element to the surface to be measured; and a light-receiving element for receiving the beams emitted by said first light-emitting element and said second light-emitting element and reflected by the surface to be measured and for outputting a signal corresponding to a quantity of light received; a converter for converting the signal output by the light receiving element into a ratio of light output by the first and second light emitting elements; and a circuit for converting the ratio output by the converter into a signal representing the height from the surface to be measured.

Claim 8

The height sensor according to claim 5, wherein the converter includes a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving element and a filter for removing direction current components of an output from said logarithmic converter circuit, and the circuit includes a rectifier circuit for rectifying an output of said filter.

Claim 9

The height sensor according to claim 5, wherein the converter includes a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving element, and the circuit includes a pair of holding circuits for holding the outputs from said logarithmic converter circuit in corresponding relation to the beams from said first and second light-emitting elements and a subtraction circuit for calculating a difference between hold values which are held in said holding circuits.

Claim 10

A height sensor for determining the height from a surface to be measured on the basis of an optical path length from a light-emitting element to the surface to be measured, comprising: a first light-emitting element and a second light-emitting element disposed at positions spaced apart from the surface to be measured; an oscillator connected to the first and second light emitting elements for causing the first and second light-emitting elements to alternately emit light; a light-receiving element for receiving beams of light respectively emitted by said first light-emitting element and said second light-emitting element and reflected by the surface to be measured and for outputting a signal corresponding to a quantity of light received; a converter for converting the signal output by the light receiving element into a ratio of light output by the first and second light emitting elements; a circuit for converting the ratio output by the converter into a signal representing the height from the surface to be measured; and a three-dimensional mirror having a shape of a triangular pyramid whose three slanting surfaces are formed as mirror surfaces and whose apex is oriented toward the surface to be measured, wherein the light-emitting elements and said three-dimensional mirror are arranged such that the beam emitted from said first light-emitting element is reflected by a first slanting surface of said three-dimensional mirror onto the surface to be measured, and such that the beam emitted from said second light-emitting element is reflected by a second slanting surface of said three-dimensional mirror onto the surface to be measured.

Claim 11

A height sensor for determining the height from a surface to be measured on the basis of an optical path length from a light-emitting element to the surface to be measured, comprising: a first light-emitting element and a second light-emitting element disposed at positions spaced apart from the surface to be measured; an oscillator connected to the first and second light emitting elements for causing the first and second light-emitting elements to alternately emit light; a light-receiving element for receiving beams of light respectively emitted by said first light-emitting element and said second light-emitting element and reflected by the surface to be measured and for outputting a signal corresponding to a quantity of light received; a converter for converting the signal output by the light receiving element into a ratio of light output by the first and second light emitting elements; a circuit for converting the ratio output by the converter into a signal representing the height from the surface to be measured; and a three-dimensional mirror having a shape of a triangular pyramid whose three slanting surfaces are formed as mirror surfaces and whose apex is oriented toward the surface to be measured, wherein the light-emitting elements and said three-dimensional mirror are arranged such that the beam emitted from said first light-emitting element is reflected by a first slanting surface of said three-dimensional mirror onto the surface to be measured, and such that the beam emitted from said second light-emitting element is reflected by a second slanting surface of said three-dimensional mirror onto the surface to be measured.

Claim 12

The height sensor according to claim 8, further comprising a reflecting mirror for reflecting the beam from said first light-emitting element onto said first slanting surface of said three-dimensional mirror.

Claim 13

The height sensor according to claim 8, wherein said light-receiving element is arranged so as to receive the beams reflected from the surface to be measured and reflected from a third slanting surface of said three-dimensional mirror.

Claim 14

The height sensor according to claim 10, further comprising a reflecting mirror for reflecting the beams reflected from said third slanting surface of said three-dimensional mirror to be made incident upon said light-receiving element.

Claim 15

The height sensor according to claim 8, wherein said first light-emitting element and said second light-emitting element are disposed at positions spaced apart a substantially identical distance from the surface to be measured.

Claim 16

The height sensor according to claim 8, wherein the converter includes a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving element and a filter for removing direct current components of an output from said logarithmic converter circuit, and the circuit includes a rectifier circuit for rectifying an output of said filter.

Claim 17

The height sensor according to claim 8, wherein the converter includes a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving element, and the circuit includes a pair of holding circuits for holding the outputs from said logarithmic converter circuit in corresponding relation to the beams from said first and second light-emitting elements and a subtraction circuit for calculating a difference between hold values which are held in said holding circuits.

Claim 18

An air spring device with a height sensor, comprising: an air spring; a reflection plate mounted to one of an upper spring member and a lower spring member of said air spring; a first light-emitting element, a second light-emitting element, and a light-receiving element which are mounted to the other one of said upper spring member and said lower spring member, said light-receiving element being adapted to receive beams of light respectively emitted from said light-emitting elements and reflected by said reflection plate and to output a signal corresponding to a quantity of light received; an oscillator connected to the first and second light emitting elements for causing the first and second light emitting elements to alternately light; reflecting means for reflecting the beams respectively emitted from said first light-emitting element and said second light-emitting element, said reflecting means being arranged to cause respective optical paths of the beams to be brought into close proximity to each other, wherein said reflecting means is a three-dimensional mirror whose slanting surfaces are mirror surfaces, the beams emitted from said first light-emitting and said second light-emitting element being respectively reflected onto the surface to be measured by means of different slanting surfaces; a converter for converting the signal output by the light receiving element into a ratio of light output by the first and second light emitting elements; and a circuit for converting the ratio output by the converter into a signal representing a height from the surface to be measured.

Claim 19

An air spring device with a height sensor, comprising: an air spring; a reflection plate mounted to one of an upper spring member and a lower spring member of said air spring; a first light-emitting element, a second light-emitting element, and a light-receiving element which are mounted to the other one of said upper spring member and said lower spring member, said light-receiving element being adapted to receive beams of light respectively emitted from said light-emitting elements and reflected by said reflection plate and to output a signal corresponding to a quantity of light received; an oscillator connected to the first and second light emitting elements for causing the first and second light emitting elements to alternately light; reflecting means for reflecting the beams respectively emitted from said first light-emitting element and said second light-emitting element, said reflecting means being arranged to cause respective optical paths of the beams to be brought into close proximity to each other, wherein said reflecting means is a three-dimensional mirror whose slanting surfaces are mirror surfaces, the beams emitted from said first light-emitting and said second light-emitting element being respectively reflected onto the surface to be measured by means of different slanting surfaces; a converter for converting the signal output by the light receiving element into a ratio of light output by the first and second light emitting elements; and a circuit for converting the ratio output by the converter into a signal representing a height from the surface to be measured.

Claim 20

The air spring device with a height sensor according to claim 15, wherein the converter includes a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving element and a filter for removing direct current components of an output from said logarithmic converter circuit, and the circuit includes a rectifier circuit for rectifying an output of said filter.

Claim 21

The air spring device with a height sensor according to claim 15, wherein the converter includes a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving element, and the circuit includes a pair of holding circuits for holding the outputs from said logarithmic converter circuit in corresponding relation to the beams from said first and second light-emitting elements and a subtraction circuit for calculating a difference between hold values which are held in said holding circuits.

Claim 22

An air spring device with a height sensor, comprising: an air spring; a reflection plate mounted to one of an upper spring member and a lower spring member of said air spring; a first light-emitting element and a second light-emitting element both mounted to the other one of said upper spring member and said lower spring member and a light-receiving element for receiving beams of light respectively emitted from said light-emitting elements and reflected by said reflection plate and for outputting a signal corresponding to a quantity of light received, said first light-emitting element and said second light-emitting element being disposed at positions spaced apart substantially a same distance from said reflection plate; an oscillator connected to the first and second light emitting elements for causing the first and second light emitting elements to alternately emit light; at least one reflecting means arranged to reflect and introduce to said reflection plate at least one of the beam emitted from said light-emitting element and the beam emitted from said second light-emitting element so as to provide an optical path difference between an optical path length from said first light-emitting element to said reflection plate and an optical path length from said second light-emitting element to the reflection plate; a converter for converting the signal output by the light receiving element into a ratio of light output by the first and second light emitting elements; and a circuit for converting the ratio output by the converter into a signal representing a height from the surface to be measured.

Claim 23

An air spring device with a height sensor, comprising: an air spring; a reflection plate mounted to one of an upper spring member and a lower spring member of said air spring; a first light-emitting element and a second light-emitting element both mounted to the other one of said upper spring member and said lower spring member and a light-receiving element for receiving beams of light respectively emitted from said light-emitting elements and reflected by said reflection plate and for outputting a signal corresponding to a quantity of light received, said first light-emitting element and said second light-emitting element being disposed at positions spaced apart substantially a same distance from said reflection plate; an oscillator connected to the first and second light emitting elements for causing the first and second light emitting elements to alternately emit light; at least one reflecting means arranged to reflect and introduce to said reflection plate at least one of the beam emitted from said light-emitting element and the beam emitted from said second light-emitting element so as to provide an optical path difference between an optical path length from said first light-emitting element to said reflection plate and an optical path length from said second light-emitting element to the reflection plate; a converter for converting the signal output by the light receiving element into a ratio of light output by the first and second light emitting elements; and a circuit for converting the ratio output by the converter into a signal representing a height from the surface to be measured.

Claim 24

The air spring device with a height sensor according to claim 18, wherein the converter includes a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving element and a filter for removing direct current components of an output from said logarithmic converter circuit, and the circuit includes a rectifier circuit for rectifying an output of said filter.

Claim 25

The air spring device with a height sensor according to claim 18, wherein the converter includes a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving element, and the circuit includes a pair of holding circuits for holding the outputs from said logarithmic converter circuit in corresponding relation to the beams from said first and second light-emitting elements and a subtraction circuit for calculating a difference between hold values which are held in said holding circuits.

Claim 26

An air spring device with a height sensor, comprising: an air spring; a reflection plate mounted to one of an upper spring member and a lower spring member of said air spring; a first light-emitting element and second light-emitting element mounted to the other one of said upper spring member and said lower spring member and a light-receiving element for receiving beams of light respectively emitted from said light-emitting elements and reflected by said reflection plate and for outputting a signal corresponding to a quantity of light received; an oscillator connected to the first and second light emitting elements for causing the first and second light emitting elements to alternately emit light; a converter for converting the signal output by the light receiving element into a ratio of light output by the first and second light emitting elements; a circuit for converting the ratio output by the converter into a signal representing a height from the surface to be measured; and a three-dimensional mirror having a shape of a triangular pyramid whose three slanting surfaces are formed as mirror surfaces and whose apex is oriented toward said reflection plate, wherein said light-emitting elements and said three-dimensional mirror are disposed on one of said spring members such that the beam emitted from said first light-emitting element is reflected by a first slanting surface of said three-dimensional mirror onto said reflection plate, and such that the beam emitted from said second light-emitting element is reflected by a second slanting surface of said three-dimensional mirror onto said reflection plate.

Claim 27

An air spring device with a height sensor, comprising: an air spring; a reflection plate mounted to one of an upper spring member and a lower spring member of said air spring; a first light-emitting element and second light-emitting element mounted to the other one of said upper spring member and said lower spring member and a light-receiving element for receiving beams of light respectively emitted from said light-emitting elements and reflected by said reflection plate and for outputting a signal corresponding to a quantity of light received; an oscillator connected to the first and second light emitting elements for causing the first and second light emitting elements to alternately emit light; a converter for converting the signal output by the light receiving element into a ratio of light output by the first and second light emitting elements; a circuit for converting the ratio output by the converter into a signal representing a height from the surface to be measured; and a three-dimensional mirror having a shape of a triangular pyramid whose three slanting surfaces are formed as mirror surfaces and whose apex is oriented toward said reflection plate, wherein said light-emitting elements and said three-dimensional mirror are disposed on one of said spring members such that the beam emitted from said first light-emitting element is reflected by a first slanting surface of said three-dimensional mirror onto said reflection plate, and such that the beam emitted from said second light-emitting element is reflected by a second slanting surface of said three-dimensional mirror onto said reflection plate.

Claim 28

The air spring device according to claim 21, further comprising a reflecting mirror for reflecting the beam from said first light-emitting element onto said first slanting surface of said three-dimensional mirror.

Claim 29

The air spring device according to claim 21, wherein said light-receiving element is arranged so as to receive the beams reflected from the surface to be measured and reflected from a third slanting surface of said three-dimensional mirror.

Claim 30

The air spring device according to claim 23, further comprising a reflecting mirror for causing the beams reflected from said third slanting surface of said three-dimensional mirror to be made incident upon said light-receiving element.

Claim 31

The air spring device with a height sensor according to claim 21, wherein the converter includes a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving element and a filter for removing direct current components of an output from said logarithmic converter circuit, and the circuit includes a rectifier circuit for rectifying an output of said filter.

Claim 32

The air spring device with a height sensor according to claim 21, wherein the converter includes a logarithmic converter circuit for logarithmically converting the signal outputted from said light-receiving element, and the circuit includes a pair of holding circuits for holding the outputs from said logarithmic converter circuit in corresponding relation to the beams from said first and second light-emitting elements and a subtraction circuit for calculating a difference between hold values which are held in said holding circuits.