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William Clark
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Aug. 21, 1782
Halifax County
North Carolina, USA
Feb. 13, 1859
Chambers County
Alabama, USA
Important Events In The Life Of William Clark:
Born Halifax County, North Carolina 1782. Son of Thomas Clark and wife Priscilla Doyle Tucker Clark (whose 1st husband was William Willis Tucker), both who are buried in a family cemetery on the former William Clark plantation in Newton County, GA.
Married ca. 1802 to Judith Craddock of Laurens Dist., South Carolina.
Appointed Surveryor General of South Carolina 1810-1814.
Removed to Laurens District where he remained for 10 years.
United States Senator from Laurens County, South Carolina 1816-1817.
In 1824, he migrated to Newton County, Georgia and there owned a plantation consisting of 1,235 acres situated on the Yellow River.
In 1837, Newton and Butts counties entered into a contract with him to build a bridge across the South River, on the Covington to Macon Road.
Settled in Chambers County, Alabama 1843, coming from Newton County, Georgia, with nine of his adult children and their families. Owned a plantation of 923 acres west of Stroud in an area later known as Bloomingdale. Neighbors included the Buckelew, Higgins, Lee, Royston. Magbee and Parker families.
Postmaster at Mount Hickory twice during the 1850s.
Died 1859 at his home, buried in Bethel Cemetery.
From "A Genealogy Of The Clark Family" by Henry William Clark, 1905:
William Clark was born in North Carolina August 21, 1782, received a good common school education and when about twenty years old married Judith Craddock, in the state of South Carolina, to which state his father and family had previously moved. He was appointed Surveyor General for the State of South Carolina, and resided at Columbia, the state capitol for four years in the discharge of the duties of that office. He then settled in Laurens District where he was engaged at farming until about 1825, when he moved to Newton County, Georgia, and settled on Yellow River, where he owned a very valuable plantation. Here he remained for many years and for several years represented his county in the General Assembly of the State, the capitol then being at Milledgeville. He removed thence to Alabama around 1843 and settled in the northern part of Chambers County where he owned a valuable farm.
In politics he was a Whig and kept well informed on the political issues of his day and was true to his party. In the matter of religious belief he and his wife were Baptist. They reared a large and interesting family of sons and daughters. He was a man of prominence and influence in his community. His life business was farming and he owned a considerable number of negro slaves and was an indulgent and humane master. He died April 13, 1859.
His wife Judith was a devoted companion and mother, loved her husband, loved her children, loved her kindred and loved to be loved. She delighted in having their friends visit the family and was a most hospitable hostess. She was a faithful and consistent member of the church of her choice and she and her husband were buried in the cemetery at Bethel Baptist Church, in the northern part of Chambers County, in the vicinity in which they had spent the latter years of an honorable and useful life, and of which they were consistent members.
The following letter was written by William Clark of Chambers County, Alabama to his son James Edwin Clark and wife Paralee B. Henry Clark, shortly after they migrated from Chambers County to Cherokee County, Texas. The letter was written in a small leather bound book approximately 4 ˝" x 7" and contains 18 pages.
The first page reads:
Chambers County
The 9th October 1847
The fathers Advice
To his Children
James E. Clark & Parralee B. Clark
(In different handwriting is written: J. E. Clark & Paralee B. Henry was married on the 14th of August 1845.)
The remaining 17 pages are as follows:
Dearly beloved Son & Daughter,
I feel desirous to give you a word of advice and as this may be the last opportunity that I may ever have, I hope you may kindly receive it.
I first exhort you to be kind and affectionate to each other, as I have good reason to believe that you have been, be careful never to speak short, abrupt or hurtful to each others feelings, and if either of you see the other in an error reprove kindly and affectionately with all the tenderness that human heart can feel; & not let such a thing as passion enter your breast. Remember that you have solemnly covenanted to live together till death shall part you & that you are wholly dependant on the Lord for every breath you draw.
If you are blessed with a family of children be careful to impress on their tender minds the importance of truth from the time they are capable of understanding as long as you have any control over them. Truth and honesty is the highest trait in the character of man or woman, although it might appear to the human heart, that falsehood might answer the best purpose for the time being, it's a wrong impression, for strict veracity will arise in the estimation of mankind generally and their own conscience will be clear. Whereas falsehood is degrading, sinful & finally destructive to the human soul.
Again I admonish you to be cautious of the company you keep. Shun backbiters, tattlers & knews (news) carriers, but never shun any person on account of their poverty, if you believe him to be honest and upwright, be cautious of making confidential friends too hastily for it may be well said, Remember well and bear in mind a faithful friend is hard to find.
Again, I exhort you to be kind to your servants, keep them in strict subjection, never correct them while you are in a passion, and when they act faithfully speak kindly to them, and gain their esteem, we all have to answer at the day of Judgement for what we do here on earth & I believe its only acting out humanity to make these creatures as happy as we can, provided we can do so and make them profitable. I don't consider giving them a loose rein as any advantage to them but quite the reverse. Never allow them to curse or swear or to use bad language in any way.
Again, I desire you if you live in a section where there is religious worship attend those places as much as you can with prayerful hearts. Keep clear of rude company as it generally leads to some bad consequences. If you meet with adversity, never despond or repine as that is often the lot of mortals here below.
Again, I admonish you not to be passionate nor fret at trifles, think well before you speak or act as reflection will generally teach you the most prudent course. If you should be surrounded by bad society, wicked people, Sabbath breakers, etc., remember that you are none the less accountable to your God. Never join them in any evil practice but teach them by example that you have been raised in a Christian land. Never give offense to any person unnecessarily, it is better to have the good will of the vilest than the ill will.
Again, I exhort you to try to be a comfort to each other in sickness and in health, stay together as much as your worldly concerns will admit of and above all things if you settle in a country where it is dangerous for women and children to be left alone, don't leave them exposed to danger.
Again, I pray you never to use bad language, never habituate yourself to cursing or swearing let it ever be so common or fashionable in the country. In conclusion I pray kind Heaven to guard, protect, defend & smile upon you is the prayer of your affectionate father till death farewell.
William Clark.
Your father & mothers ages –
William Clark was born the 21st day of August 1782
Judith Clark was born the 1st day of August 1787
Their childrens ages –
1st Thomas Craddock Clark was born the 14th day of March 1807
2nd Robert Archer Clark was born the 2nd day of April 1809
3rd John Robert Clark was born the 1st day of April 1811
4th William Thomas Clark was born the 12th day of February 1813
5th Adeline Craddock Clark was born the 22nd day of December 1815
6th Harriet Kilgore Clark was born the 11th day of November 1817
7th Mary Ann Clark was born the 23rd of August 1819
8th James Edwin Clark was born the 27th day of September 1821
9th Elizabeth Green Clark was born the 31st of August 1823
10th Judith Caroline Clark was born the 15th of October 1825
11th Martha Katharine Clark was born the 14th of April 1828
12th Charlotte Susan Clark was born the 15th of August 1830
Dear Son,
I want you to practice spelling, reading & writing and write to your father & mother often, and don't neglect reading this little Book often & keep it as long as you live and you may always know the age of your father, mother, brothers and sisters.
William Clark.
(Included on the last two pages of the book)
To Make Cooks Pills:
One ounce Calomet
One ounce bitter Aloes
One ounce Rhubarb
Pound them well together in a mortar till they are fine and mixed together. Add water enough to make it stiff enough to make into pills. The above quantity of medicine will make from 240 to 300 pills. 5 pills is a common dose for a grown person.
(In another's handwriting is written)
William Clark my father departed this life on the 13th of April 1859
Judith Clark my mother departed this life on the 21st of November 1856
Last Will & Testament of William Clark
The State of Alabama
Chambers County
In the name of God Amen. I William Clark of the County and State aforesaid being of sound mind and memory considering the uncertainty of this frail body and transitory life do therefore make, ordain, publish and declare this to be my last Will and Testament that is to say first after all my lawful debts are paid and discharged the remainder of my Estate be equally divided among my children: John R. Clark; William T. Clark; Adeline Clark Higgins; Harriette Clark McIntosh; Mary A. Clark Magbee; James E. Clark; Elizabeth G. Clark Parker; Judith Clark Bowling; Martha Clark Jordan and Charlotte Clark Henry. In the following manner to wit.
Item 1. That my two eldest sons John R. Clark and William T. Clark whom I appoint my lawful Executors. In reasonable time after my decease, appoint either three or five free holders to lot off all my negroes, with the exception of old Dave and Cassey, unto ten equal shares as nearly as possible with an Eye Single to the comfort of the negroes so far as not to separate the mother and their youngest children and that each of my children have one share and all that the shares like of being equal in valuation, be made so in money arising from the sale of my other property.
Item 2. That the negroes and money allotted and given to my Daughters I give and devise the same to them their sole and separate use during their lives from the Debts, Constraints and Controle of their husband and at their death to their children.
Item 3. That all my stock of all description, household and kitchen furniture and all other things of value be advertised, put up and sold to the highest bidder on a credit of twelve months.
Item 4. That all my land improved and unimproved be sold to my Executors at private Sale if they can by that means obtain a fair price and credit of one, two and three years, but in case of failure to sell privately, they advertise and exchange to sale to the highest bidder on a credit of the same time.
Item 5. It is my will that my old Negro man Dave stay with some one of my children and that my Executors retain money on their hands sufficient to support him during his life and that Cassey be supported in the same way provided she become helpless and cannont maintain herself.
In witness whereof I have hereunto set my hand and seal this 27th day of November In the year of our Lord 1857.
Wm. Clark
In presence of –
Thomas B. Royston
John W. Magbee
Slave Inventory of William Clark, dated August 25, 1859.
Dave - No $ Value
Cassey - No $ Value
Simon, Age 51, $800
Toby, Age 45, $950
David, Age 35, $1250
Barney, Age 24, $1500
Henry, Age 22, $1500
Sanders, Age 17, $1250
John, Age 14, $1300
Peter, Age 13, $1260
George, Age 13, $1175
Alford, Age 9, $1025
Logan, Age 7, $800
Filmore, Age 5, $575
Quincy, Age 8, $775
Milly, Age 43, $550
Fillis, Age 41, $400
Frances, Age 20, $1100
Nancy, Age 13, $1200
Lucinda, Age 10, $1000
Starling Tucker (1770-1834)
Elizabeth Doyle Clark Wallis (1774-1854)
John Clark (1780-1870)
Nancy Clark Burdett (1784-1864)
Family links:
Thomas Clark (1753 - 1837)
Doyle Tucker
Clark (1750 - 1840)
Clark (1787 - 1856)
Thomas Craddock Clark (1807 - ____)
Robert Archer Clark (1809 - ____)
John Robert Clark (1811 - 1870)
William Thomas Clark (1813 - 1895)
Adaline Craddock
Higgins (1815 - 1901)
Harriette Kilgore
McIntosh (1817 - ____)
Mary Ann
Magbee (1819 - ____)
James Edwin Clark (1821 - 1886)
Elizabeth Green
Parker (1823 - ____)
Judith Caroline
Phillips (1825 - 1906)
Martha Katherine
Jordan (1828 - ____)
Charlotte Susan
Wise (1830 - 1900)
Starling Tucker (1770 - 1834)
Elizabeth Doyle
Wallis (1775 - 1854)
John Clark (1780 - 1870)
William Clark (1782 - 1859)
Burdett (1784 - 1864)
Calculated relationship
Bethel Baptist Church Cemetery
Chambers County
Alabama, USA
Created by:
Record added: Jan 26, 2009
Find A Grave Memorial# 33292379
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Debra Graves Dawson
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text:
Where WKU, U of L and UK could play this postseason
Conference USA announces details of TV schedule
Tops focused on finishing
Junior averaged 11.71 assists in two matches
Honor is first of sophomore's career.
WKU committed to eliminating turnovers and penalties
The Monday Muckraker, September 26, 2016
Arnold Palmer was one of the most popular figures ever in golf, generating a fervid fan base while winning seven major championships among his 62 PGA titles.
Although not big in numbers, that doesn't stop the Warren Central football team from playing with heart.
It's the final Sports Connection show for the month of September.
Episode to discuss former WKU coach Bobby Petrino
Lady Toppers sweep Charlotte
Pledge is 16th toward 2017 class
Hilltoppers host Houston Baptist next
WKU has been disciplined last two games
Commodores come back in 31-30 victory
WKU wins 39th straight conference home match
The Butler County Bears held a district match-up with Owensboro Catholic.
Grayson County was hoping to pick up its first win against Breckinridge County.
The undefeated Glasgow Scotties host Greenwood in varsity football action.
Warren East hit the road hoping to pick up its second win of the season against Barren County, who wants its first win this year.
Logan County was hoping to end its losing streak against Hopkins County.
A huge district match-up between the defending state champ South Warren and the undefeated Franklin-Simpson Wildcats.
Mike Cleff
Chad Bishop
Dominique Yates
Click Here to access the online Public Inspection File
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subset: commoncrawl


text:
Pest Myths: 'Debugged'
Being in the pest control business for almost 75 years, we've heard plenty of tall tales and misinformation about pests.Read more
What's the buzz?
Do you hear it? That sound! Yes, that's the one. The familiar sound of bees. The buzz that fills your ears in the warm months of summer.Read more
Let the Pest Olympics Begin!
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Pests of the Sky
Look up! Do you see it? No, it's not the blue sky, that plane passing overhead, or that bird flying by; it's the pests buzzing right above your head.Read more
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It turns out those pesky critters that call your sheets home have color preferences.Read more
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text:
There is apparently not much daylight today between Sen. Mitch McConnell and her Democratic challenger, Alison Lundergan Grimes, on the issue of Kentucky coal. Grimes this morning launched full-throated support of the coal industry — when James River Coal was announcing layoffs of more than 500 miners.
The company blamed market conditions.
McConnell blamed what he called President Obama's "war on coal."
The statement from Grimes, Kentucky's secretary of state, did not mention the James River situation specifically, and a Grimes spokeswoman said another statement would be forthcoming. But this morning, Grimes sought to distance herself from the president's pending climate rules on power plants.
The Washington Post reported six days ago that those new rules were to be issued this month, and that they would not be as stringent and as hard on coal as initially proposed.
Still, Grimes statement called "coal miners are Kentucky's heart and soul" and that "families across the Commonwealth rely on coal to keep food on the table, gas in the car and roofs over their heads." The statement went on to say:
As the EPA releases their new emissions standard this week, I call on the President to do the right thing and develop a policy that does not threaten Kentuckians' livelihoods. Coal keeps the lights on in Kentucky – plain and simple – and I will not stand idle as overreaching regulation adversely impacts jobs and middle-class families. Any new regulations must take into account the impact on Kentucky jobs and be based on current technology that will not drive Kentucky coal out of business.
She also attempted to blame McConnell for allowing coal jobs in Kentucky to dive:
Despite Senator McConnell's rhetoric on coal, Kentucky coal jobs have fallen to the lowest number since 1927 under his so-called 'leadership' in Washington. As your next U.S. Senator, I will continue to support the coal industry and its miners through common sense policies – not lip service. I will fight for incentives for companies to continue to invest in coal, push for loan guarantees from the federal government for clean coal technology and facility upgrades, and help get hardworking Kentuckians back to work.
Absent from the statement was any recognition on the science of climate change or its impacts in our region or elsewhere. Or any talk of what Kentucky may need to do to adapt to climate change, a subject featured in a recent three-part series by The Courier-Journal.
UPDATE (6:13 pm): McConnell later in the day put out a statement saying Grimes' charges were a bunch of baloney. Now I'm waiting for another statement from Grimes, firing back at McConnell, etc etc. And so it goes, I guess, until election day.


text:
|Publication number
|Publication type
|Publication date
|Aug 3, 1971
|Filing date
|Jan 18, 1968
|Priority date
|Jan 18, 1968
|Also published as
|Publication number
|Bowker John Kent
|Original Assignee
|Itek Corp
|Export Citation
|BiBTeX, EndNote, RefMan
|Patent Citations (4), Referenced by (27), Classifications (5)
|External Links: USPTO, USPTO Assignment, Espacenet
United States Patent lnventor Appl. No.
Filed Patented Assignee INTERFEROMETER 22 Claims, 13 Drawing Fks.
US. Cl.
Int. Cl Field of Search References Cited UNITED STATES PATENTS 356/106, 356/156 G0lb 9/02 356/106- Primary Examiner-Ronald L. Wibert Assistant Examiner-Conrad Clark Aliorne s- Homer 0. Blair, Robert L. Nathans, Lester S.
Grodberg and David A. Rich ABSTRACT: An interferometer with a laser source focused on a pinhole produces monochromatic, coherent light with a spherical wave front. A beam splitter divides the light along light paths which are directed through coupling mirrors to the opposing parallel reflecting surfaces of a movable rigid body stage plate. Reflected energies returning along incident paths normal to the reflecting surfaces are directed back through i the beam splitter to an exit pinhole where they are combined and interfere. A photoelectric detector produces an electrical signal in response to the variation of light intensity of the interfering energies. The number of intensity changes, corresponding to the number of interference fringes, is accumulated in a fringe counter which produces a measure of the linear translation of the stage plate with respect to a fiducial indicating a reference point at the optical center of the system, i.e. the center of the light paths. An embodiment is described and illustrated for measuring two coordinates, e.g. a two axes measurement system. In one form a servo system in response to the counts for each axis positions a movable member.
Patented Aug. 3, 1971 ll Sheets-Sheet 1 John Kent Bowker INVENTOR.
25M 14. QM Attorney.
ll Sheets-Sheet 2 John Kent Bowker INVENTOR.
Patented Aug. 3, 1971 3,597,091
11 Sheets-Sheet 5 Flg 3 John Kent Bowker INVENTOR.
1M 74. flack Attorney.
Patented Aug. 3, 1971 3,597,091
11 Sheets-Sheet 5 Fig.5
John Kent Bowker INVENTOR.
Patented Aug. 3, 1971 ll Sheets-Sheet 6 John Kehf Bowker INVENTOR.
Patented Aug. 3, 1971 11 Sheets-Sheet 7 Patented Aug. 3, 1971 11 Sheets-Sheet 8 Fig. IO
John Kenf Bowker INVENTOR.
33w ,4. Rich Attorney.
Patented Aug. 3, 1971 ll Sheets-Sheet 10 m Eu WEE: f A momma; 3 0
N e mm r .IDUEQ amkzou x wmm 2 5N NMN/ y f nw m unnn mmm! mmm 0 8 AP f mm 1? m \l u i EN John Kent Bowker mvzwrozev Attorney.
Patented Aug. 3, 1971 ll Sheets-Sheet 11 wow wow
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mom on com won John Kent Bowker INVEN'IOR.
25M 4. QM Attorney.
INTERFEROMETEIR IMPROVED INTERFEROMETER The present invention relates to interferometers for use in extremely accurate measuring engines and positioning devices.
The use of interferometers in measuring engines is well known in the art. The so-called Michelson interferometer was used successfully to measure a meter rod accurate to one part in The Michelson interferometer is described throughout the literature and is very well known; for example, Introduction to Geometrical and Physical Optics" by Joseph Morgan, published in I953 by McGrawI-Iill Book Company. Inc., pages 223 to 227 and particularly illustrated on page 224.
In the Michelson interferometer and other subsequent variations, an axial displacement measurement is effected by counting interference fringes produced by the motion of a movable reflecting surface relative to a fixed reflecting sur face. In general, a single source of light is collimated and the parallel rays are directed to a beam splitter; for example, a semireflecting mirror oriented at 45. The beam splitter reflects light to a reflecting surface orthogonally oriented relative to a second reflecting surface intercepting the light energy transmitted through the beam splitter.
Further, when the moving reflecting surface is rotated relative to the fixed or reference reflecting surface, spurious fringe counts appear which falsely indicate linear displacement producing errors proportionate to a*, where a is the angle of rotation, if the device fulfills Abb's principle, and errors proportional to ka if the Abbe condition is not fulfilled. To avoid the problem of undesirable rotations such an interferometer is typically massive and requires complicated drive systems. It remains extremely sensitive to changes in ambient conditions, a delicate instrument. Such instruments are inordinately expensive for use in a broad range of applications inconsistent with laboratory conditions but which require highly accurate measurements.
In contrast, the present interferometer is immune to a broad range of variables in ambient conditions and is free of errors caused by angular or rotational motion of any magnitude. Consequently, an interferometer embodying the invention requires only a relatively inexpensive, simple, low inertia drive system.
In the past, angular motion produced apparent linear displacement errors as much as two orders of magnitude for angular motion of less than one minute of arc in one coordinate and less than one second of arc in two coordinates.
Thus, prior art interferometers which are designed for measurements along two or more orthogonal measurement axes are particularly sensitive to any errors due to spurious angular or rotational motions.
All classical interferometers are subject to linear displacement error of at least cosine a where a is the angle of rotation.
In accordance with Abbs principle if the measuring device and the length to be measured are placed in line in such a manner that the measuring device and the object move as a single body, rotational errors are minimized and as noted above, represent a linear displacement error proportional to the square of the angle measured in radians. A single axis interferometer tends to fulfill Abbs principle, particularly since the motion of the movable mirror is severely constrained. At best, however, there is an error. In contrast, an interferometer embodying the present invention is capable of measuring linear displacements independently of the angular position, or even rotation of the object to be measured relative to a linear displacement translation direction.
No known device, however, fulfills Abb's principle when simultaneous measurements are made with respect to a pair of orthogonal translation axes.
The cross-coupling between the two axes due to rotation produces at least cosine error in one axis and sine error in the other, resulting in a linear displacement error proportional to a constant times the angle of rotation in radians.
Prior art measuring engines are subject to errors in translation due to changes in levelling and vibration. The errors are aggravated by wear of the ways. In general measurements with such engines can be made with accuracy only after the system, especially the object to be measured, is at rest. Thus, the high accuracy of an interferometer is, heretofore, only available statically. During motion of a stage carrying the object to be measured, errors are produced in translation due to motions ofthe stage in 6 offreedom. As used herein, the 6 offreedom include rotations about three orthogonal axes and translations along three orthogonal axes. Where measurements are desired only in 2 of freedom, e.g., translation in X and Y, motions of the stage in the remaining degrees of freedom produce excessive errors in apparent linear displacement in the desired translation directions.
In contrast with the above, the interferometer of the invention being immune to linear displacement errors due to rotational motions, retains its accuracy for all degrees of freedom of measurement. In multiple axes systems, no cross-coupling takes place due to rotation.
Because the present interferometer responds only to displacements in desired degrees of freedom, e.g., translations in X and Y, accurate measurements are produced at all times while the object to be measured is in motion. This result enormously increases the usefulness of interferometers for applications requiring dynamic measurements such as control functions. Here the accuracy of measurement while the object to be measured is in motion is the same as that while it is at rest. Furthermore, the instant interferometer is completely free of errors due to wear, variations in levelling and vibrations.
Although the interferometer of the invention is comparatively inexpensive, simple and of low inertia, it is relatively rugged and reliable in operation; measurements of a high order of accuracy are readily reproducible. These benefits are derived from the insensitivity of the system to spurious rotation.
It is therefore an object of the invention to provide an improved interferometer capable of extremely accurate linear displacement measurements independently of angular or rotational motion of the object to be measured with respect to other elements of the system.
Yet another object of the invention is to provide an interferometer of improved accuracy which requires only a relatively inexpensive, simple, low mass drive system.
Still another object of the invention is to provide an interferometer of improved accuracy which is relatively immune to its environment and may, therefore, be used for a broad range of applications outside laboratory conditions.
A still further object of the invention is to provide an interferometer of improved accuracy which is truly rugged and reliable in operation; an interferometer which yields a high order of reproducible measurements of great accuracy and free of the effects of wear.
Yet a further object of the invention is to provide an improved control device for positioning a movable member with high accuracy.
Other and further objects of the invention will be apparent from the following description, taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.
In accordance with the invention there is provided mensuration apparatus. The apparatus includes means for providing radiant energy along a first input axis. There are means for providing radiant energy along a second input axis. A rigid body has a pair of reflecting surfaces. The first reflecting surface intersects the first input axis. The second reflecting surface intersects the second input axis. Means are further provided for directing a portion of the radiant energy orthogonally to each reflecting surface independently of the angle of intersection of the reflecting surface to its corresponding input axis.
In one form of the invention the radiant energy is monochromatic, coherent light. The reflecting surfaces are parallel and the light energy is derived from a common source.
In another form of the invention, means are provided for varying the phasing of one polarization component relative to another of the energy along the first input axis.
In another form of the invention the rigid body has a plurality of mutually orthogonal pairs of parallel reflecting surfaces.
The energy means and the portion directing means are rigidly coupled together to define a radiation path. Means are provided for producing relative motion between the rigid body and the rigidly coupled means. A reference point is indicated at the center of the path between the radiant energy means. An indication is produced of the relative translation of the rigid body from the reference point.
Means are also provided to position a member in accordance with a control signal derived from the indication of the translation of the rigid body.
In the preferred embodiment the apparatus is an interferometer in which means are provided for directing the reflected energies to a common interference region. The light energy has a spherical wavefront. Means are further provided for indicating a reference point at the geometric center of the light paths. The reference point is at the intersection of the light paths for translation axes.
Means are included for detecting and counting interference fringes produced by the reflected energies, providing thereby a measure of the translation of the rigid body from the reference point, independently of the rotation of the rigid body with respect to the light paths.
While the interferometer ofthe invention is useful with radiant energy in its many forms, including, but not limited to electromagnetic and sonic radiation, the preferred embodiment is an optical instrument utilizing light energy. The term light as used herein includes, but is not limited to, light frequencies extending from the infrared region to the oltraviolet region.
In one form of the' invention then the radiant energy is monochromatic, coherent polarized light energy from a common source for a selected coordinate axis. The reflecting surfaces are preferably parallel. Means are provided for moving the rigid member with respect to a reference point. A displacement of the rigid members produces a changing state of interference to provide an indication of the extent of the displacement from the reference point.
The interferometer of the invention may be used to provide measurements of displacements along two or more orthogonal axes. The rigid member then includes a plurality of reflecting surface pairs. A plurality of sources of radiant energy are included. Radiant energy is then directed to each reflecting surface of each reflecting surface pair. Reflecting energy is directed from each reflecting surface of each reflecting surface pair to a corresponding interference region. Means are provided for moving the rigid member in two or more orthogonal directions and for detecting a plurality of states of interference of the reflected energies in a plurality of the regions. Separable interference fringe patterns are thus produced with respect to a plurality of orthogonal translation axes. In a preferred embodiment a continuous wave laser is used as a source of light energy.
The phase of one light portion is variable relative to the other by the insertion of an odd or extra phasing mirror having a metallic reflecting surface. The relative phase of the energies is varied by varying the angle of incidence to the mirror.
Orthogonal polarization components of the reflected energies are separated after interference along separate sensing paths.
In another form of the invention, a measuring apparatus is provided. The apparatus includes means for providing a first reference frame to locate a fixed reference point. The means include a rigid source means fixed in the frame. Fiducial means indicate a reference point fixed in the frame with respect to the rigid source means.
A second reference frame means is provided. The frame means are relatively displaceable therebetween with more than l of freedom. Means coupling the frame means include a medium extending from the rigid source means along at least two paths to the second frame means. Each medium path length varies with displacement of the second frame means with respect to the reference point. The difference between the medium path length varies only with a displacement in 1 of freedom of the second frame means relative to the fixed reference point. The medium path lengths difference is invariant with respect to a relative displacement between the frame means in any other degree offreedom.
The apparatus further includes means for providing an indication of a displacement in l of freedom of the second frame means with respect to the reference point independently of a displacement thereof with respect to the reference point in any other degree of freedom.
The interferometer of the invention is insensitive to rotation of the object to be measured because the frame of measure ment, e.g., a measurement axis along which the optical path difference is determined, rotates with the object independently of any direction implied by the existence of two sources and the line between them, the means of translating the object or a fixed point of reference.
The optical path length difference so determined thus varies only for translations along the measurement axis and is unvariant for any rotation of the object.
IN THE DRAWINGS FIG. I is a 5 view ofa schematic diagram of an interferometer embodying the invention;
FIG. 2 is a diagram of optical paths illustrating an aspect of operation of the embodiment in FIG. 1;
FIG. 3 is a diagram of optical paths illustrating another aspect of the operation of the embodiment in FIG. 1',
FIG. 4 is a plan view of a more detailed schematic diagram of a single translation axis interferometer embodying the invention;
HO. 5 is a perspective view of a two axes interferometer embodying the invention, particularly illustrating the mechanical drive system and relative orientations of the opposing light paths for each axis;
FIG. 6 is a perspective view of the optical arms as removed from the drive table;
FIG. 7 is a plan view in schematic form of the interferometer in FIG. 5;
FIG. 8 is a side view in schematic form of the interferometer in FIG. 5;
FIG. 9 is a front view in schematic form of the interferometer;
FIG. 10 is an enlarged, plan view in schematic form of a Y- axis optical assembly in the inte ferometer of FIG. 5 taken along the lines X-X' in FIG. 9;
FIG. 11 is a schematic circuit block diagram illustrating a positioning apparatus embodying the invention;
FIG. 12 is a machine tool embodying the interferometer of the invention useful in the apparatus of FIG. 12; and
FIG. 13 is a plan view in schematic form of a modification of the interferometer in FIG. I illustrating a light source disposed between a pair of inwardly reflecting surfaces.
Referring now to the drawings and with particular reference to FIG. I, there is here illustrated an interferometer embodying the invention. A laser light beam is focused on a pinhole to provide a coherent source of light with a spherical wavefront. The light is coupled to a beam splitter which transmits half the energy and, through coupling mirrors, to one of a pair of opposing, parallel reflecting surfaces of a movable rigid body stage plate. The other half of the energy is reflected from the beam splitter and, through coupling mirrors, to the other reflecting surface. A fiducial marks the geometric center or fixed reference point 0 for the optical paths.
The stage plate is shown rotated relative to the central optical axis and displaced to the left of the reference point 0. The normal ray, and only the normal ray, reflected from each reflecting surface travels back along its incident path and is directed by the beam splitter through a pinhole where the reflected energies combine and interfere. A photoelectric detector in the interference region converts the varying light signals resulting from interference into an electrical signal in dicative of the linear displacement of the stage plate from the reference point. The output signal is in the form of fringe counts, i.e., the number oflight maxima.
A laser directs a coherent beam of monochromatic light to a pinhole A in a plate 11 which produces a spherical wavefront of light. The light travels to a beam splitter 12 and is divided into two portions along two paths so that one light portion travels in a first bundleof rays 13 with a spherical wavefront along a first optical path to the right, as shown, along the central optical axis 28 and the other light portion in a second bundle of rays 14 with a spherical wavefront along a second optical path to the left, as shown, along the central optical axis 28.
The rays 13a and Ma refer to the incident rays normal to the reflecting surfaces 17 and 22 at the points F and F, respectively. The light reflected from the beam splitter I2 is directed to a coupling mirror 15 oriented, e.g., at 45 and, thence, to another coupling mirror 16 to the reflecting surface 17 ofa stage plate 18.
The light which is transmitted by the beam splitter 12 is directed, e.g., to a 45 coupling mirror 19, then in sequence to coupling mirrors 20 and 21 to the reflecting surface 22 of the stage plate 18. The reflecting surfaces 17 and 22 are preferably ground parallel. An object 23 to be measured is supported by the stage plate 18.
Means providing a first reference frame include the light source, the beam splitter and the coupling mirrors, all rigidly coupled together. The center of the optical paths is a fixed reference point in the first frame. The stage plate is a rigid body means providing a second reference frame. The first and second frames are relatively displaceable with 6 of freedom. The only displacement sensed, however, is the displacement along a measurement translation axis in the second frame relative to the fixed reference point in the first frame. The stage plate as shown here is a square and is rotated at an exaggerated angle from the central optical axis 28.
A spherical wavefront is produced at the pinhole A; hence, one and only one ray from the bundle l3 directed from A to the reflecting surface 17 is incident to and reflected normal to the surface 17 at the point F. Hence, it follows the same path back to the beam splitter 12 where a portion is transmitted through a pinhole B in an exit plate 25 to the input face of a detector 26 in the interference region.
To avoid errors, a constant difference between the optical path lengths for a given measurement axis is required except for translations along the measurement axis. This condition occurs if and only if the incident light ray is reflected back along its incident path, i.e, the angle between the incident and reflected ray is zero.
Similarly, one and only one ray l4a of the light portion transmitted through the beam splitter 12 is normal to the reflecting surface 22 at the point F. The ray 14a returns along the same path to be reflected in part by the beam splitter 12 through the pinhole B to interfere with the ray 130 at the input face ofthe detector 26.
OPERATION point on the object to be measured from the reference point 0.
A measurement is made then in the following manner: A fiducial representing the reference point 0, such as a crosshair, is viewed through a microscope. The displacement of the point from the point is measured by moving the stage plate until the fiducial coincides with the point This has the effect of decreasing the length of the path of the normal incident ray 1311 and increasing the path of the ray 14a.
The stage plate is then moved until the point is under the fiducial. As the stage plate moves from the point to the point the length of the path 13a increases and that of the path 14a decreases. As the stage plate 18 moves, its displacement relative to the point 0 constantly changes the difference between the path lengths 13a and 140. This in turn produces a changing interference condition which is detected by the detector 26.
Referring now to FIGS. 2 and 3, the principles of operation of the interferometer in FIG. 1 will be discussed.
An important feature of the interferometer in FIG. 1 is its relative freedom of errors in linear translation measurement as the stage plate 18 is rotated through an angle a about a conventional translation axis, say the X axis. Note that the stage plate may be constantly rotated at some rate without interfering with such a translational measurement. In particular, for rotation about 0, the path difference 4x for all values of angle a remains a constant. This result is derived from an analysis of FIG. 2.
Consider then that the stage plate is displaced a distance x from the fiducial or reference point 0 at the geometric center of the total optical paths 2D, the distance between the sources AB and A'B, taken from A as virtual image for A and B as virtual image for B. Then AB is coincident with A'B' when the paths are unfolded since the path from the beam splitter 12 to A is the same as the path from it to B.
In order to establish that the system is indeed free from errors due to a displacement in a degree of freedom other than translation along the measurement axis in the stage plate, let us consider the path difference when the stage plate is rotated an angle a relative to the central axis 28 and is displaced in translation from the reference point 0 along the normal to its central plane 29 parallel to the reflecting surfaces.
To determine the signal produced at the face of the detector 26 in the interference region, the path difference may be calculated between the paths 13a and 14a. The stage plate of width w is ground so that the opposing reflecting surfaces 17 and 22 are parallel. In the diagram of FIG. 2 the paths 13a and 14:: are unfolded, showing the interfering beams taking the path 13a to the left and 14a to the right.
Assuming the length of the distance between the sources to be 2D, the virtual image which appears at B in the diagram of FIG. 2 is unfolded to coincide with the pinhole A. There appears then to be for purposes of analysis two rigidly coupled sources of energy defining the central optical axis 28 with the fixed reference point at 0. Let x be designated as the distance from the fiducial point 0 along the normal to the central plane 29 of the stage plate, here shown rectangular.
The calculation of the optical pathlengths AFB and AF'B' may be obtained directly in terms of the distance x from 0 along the normal to the central plane 29. Since A and B are coincident, as noted above, path 13a is normal to the reflecting surface 17. Similarly, path is normal to surface 22. Construct a line 30 parallel to the central plane 29 and passing through 0. Since A0=D and A'0=D, the distance along the extension of paths 13a and 14a from A or A to the line 30 is D cos a. The point of reflection of path 13a lies a distance w/2-x from the line 30, thus the distance AF=D cos a-w/2+x. Since the returning path is coincident, the total path is Equation l AFB=2(D cos a( w/2+)x).
Similarly the path Equation (2) AF'B'=2 (1) cos a(w/2)x) The path difference then is Equation (3) AF'B'-AFB=2 (1) cos a-( w/2+)x)2 (D cos a( w/2')x)=4x It will be seen then that given a translation x from a point in the stage plate frame, the path difference is invariant with respect to rotations of the stage plate about the reference point 0. Thus, a translation measurement with the interferometer illustrated in FIG. 1 is completely independent of the angle of the stage plate 18 to the optical axis 28 if the reference is taken at the center point between the apparent sources A and A.
When the stage plate is moved from the location X, to another position X the displacement is Equation (4) X ,=X,X,
When the path difference is equal to an integral number n of wavelengths, i.e.,
Equation (5) 4x=n)\, constructive interference occurs. When the path length is an odd number of half-wavelengths, that is, Equation (6) results.
The total number of changes represents the displacement along a measurement axis normal to the reflecting surfaces.
Note that regardless of a displacement in any other independent degree of freedom, no change in the interference condition takes place.
The light intensity in the interference region at B goes through a maximum each time Equation (7) .r=n()t/4) The variation from light maximum to light minimum back to light maximum produces fringe counts as the stage plate 18 is translated from the point X, to the point X Then Equation (8) X,,=(NA/4), where Equation (9) n n,=N is the number of observed counts. It will be apparent that the least displacement measurable by simply counting intensity maxima is equivalent to one-fourth of a wavelength. Thus, the lease displacement measurable by counting intensity maxima is half as great as that obtained with the fixed reference mirror type of interferometer.
For a neon-helium laser the light beam produced characteristically has a wavelength of 0.632815 microns. The least measurement of displacement would then appear to be 0.159704 microns which is equivaient to 6.28756 microinches. However, by using two light polarizations, one of which will not interfere with the other and by placing these in quadrature through the use of a quarter wave plate or similar device, the least count is reduced to one sixteenth of a wavelength, i.e., 0.039926 microns or 1.5719 microinches.
The least measurable interval can be substantially reduced by using phase comparison techniques which are known in the art.
4x=(2 n+l)()\/2) destructive interference MECHANICAL IMPLICATIONS If the points A'B and AB in the first frame are considered to be fixed support points, a linkage medium from A'B to the surface 22 and another from point AB to the surface 23 may be introduced.
The linkage medium may be a spring with a net force in the direction of the fixed point and a substantially frictionless slidable coupling to a parallel surface. In accordance with the principle of least action, the spring conforms with the shortest path between its fixed support point and its corresponding parallel surface; i.e., it always assumes the least pathlength and, therefore, is always normal to its coupled parallel surface. With rotation of the stage plate counterclockwise about the reference point 0, for example, the pathlengths decrease equally, the springs always operating to find the least path normal to the parallel surfaces. Conversely, rotation of the stage plate clockwise about the reference point 0 increases the pathlengths equally. The difference between the pathlengths then remains a constant, except when the stage plate is translated from the reference point along the normal to the central plane of the stage plate. The measurement of pathlength difference may be indicated, for example, by sensing the spring forces with appropriate transducers and comparing them.
In a sense the incident light ray normal to each reflecting surface is effectively slidably coupled to the surface. Thus, the term linkage medium or coupling medium in this context includes, but is not limited to, media coupling means providing a first frame of reference to define a fixed reference point, such as the earth, i.e., observer's, frame, to means providing a second frame of reference, such as the stage plate or the object to be measured.
The coupling medium has the property of conforming to the least path from a fixed support point in the first frame normal to a surface fixed in the second frame.
The mechanical equivalent of the interferometer of FIG. 1 is more nearly realized by replacing the coupling mirrors with pulleys fixed in the first frame relative to a single fixed support point, for example, in place cfthe beam splitter. The coupling medium extends from the fixed support point around the pulleys to the parallel surfaces; the pathlengths varying between the pulleys directly coupled to the parallel surfaces.
The coupling medium may be inelastic if, for example, a device is included which operates to maintain the medium taut in response to rotation of the stage plate.
The pathlength difference for an inelastic medium is always directly indicated by the takeup device maintaining a taut coupling. The direction of translation is immediately indicated by the direction of rotation if the takeup device is, for example, rotary.
A similar result to the above is achieved by introducing the coupling medium from a fixed point between, for example, a pair of parallel reflecting surfaces rigidly coupled together, which now reflect inwardly. In such an embodiment of the invention monochromatic, coherent light emanates from a pinhole A and a portion is transmitted through a beam splitter to a reflecting surface. The other portion is reflected by the beam splitter and coupling mirrors which direct it in the opposite direction from and colinear with the first portion to a parallel reflecting surface. As noted above, the two reflecting surfaces face each other. Again, the normal rays are reflected back through the beam splitter through an exit pinhole.
ABBE PRINCIPLE In the past all measuring engines which met the Abbe condition most closely at least were subject to translational displacement errors due to rotation in proportion to the cosine of the angle of rotation of one element of the engine relative to another. No known measuring engine meets the Abbe condition, however, while one element is in motion relative to another, because some displacement takes place in such a condition in all 6 of freedom.
With respect to any frame of reference, all moving bodies have 6 of freedom, displacements in translation along the mutually orthogonal X, Y and Z axes, and angular displacements about the X, Y and Z axes. If one wishes to measure displacemerits in a selected one or two degrees of freedom, to avoid error, the measurement so made must be independent .of displacements in any other degree of freedom.
In the past, displacement measurements, angular measure ments and distance measurements of objects have always been taken in the observer's frame. Thus, while the object is in motion, the displacements in the 6 of freedom are not independent relative to the observers frame. If, however, the subject being measured can be isolated therefrom, the object itself becomes a reference frame and carries its own coordinate system which is invariant with respect to and independent of the observers frame. If the object to be measured is planar, all measurements of points in the plane of the object with respect to its own coordinate system are thus independent of any motion of the object relative to the observer's frame.
In the present invention, the object to be measured presents a second frame of reference within which it and the measurement scale are indeed rigidly coupled together, thereby completely meeting Abbs condition.
Displacement from a fixed reference point in the first frame may be readily determined by fixing the location of a point in the second frame coincident with the fixed reference point. A measurement of the position of a point in the second frame relative to its own coordinate system, e.g., along the single translation measurement axis, at once becomes a measure of its position relative to the fixed reference point in the first frame.
In the present interferometer, the position of the exit pinhole 5 is uniquely determined. From the analysis of FIG. 2, it is indeed apparent that the points A and B must be equidistant from the reference point 0. This is the only location for the point B at which the center of the interference fringe pattern is stationary. Since the location of the point B is fixed for all values of angle a, or for that matter a displacement in any other independent degree of freedom, the problem of a shifting interference fringe pattern due to misalignment is totally eliminated. Again, this result is unique.
The diameter of the pinhole B in the plate 25 is subject to opposing requirements. In the first instance it is desirable for the hole to be as large as possible to gather as much light as possible. Secondly, the hole should be as small as possible to preserve fringe visibility.
The nature of the interference pattern at the plane of the plate 25 and the necessary size of the pinhole B may be analyzed by referring to the diagram in FIG. 3. The diagram in FIG. 3 is derived by rotating the arm indicated by the optical path 14 about the reference so that the image at B coincides with the image at B and the virtual images equivalent to A and A are derived by extending the rays to indicate the virtual image sources behind the mirrors.
The displacement r from BB is the distance off the axis in the plane of the plate 25. It is useful to determine the path difference A'r-Ar as a function of r. From FIG. 3 it will be apparent that:
Equation (1) Equation (1 1) Ar =r +BA +2rBA sin a, so that l +r +2rgiiz sin a Since 1- is much less than BA or BA, Equation (14) 2 I I AI A =B AI A sin 2 BA(1+%T +21 BA slna The analysis yields the result that the interference pattern is composed of a set of concentric circles or, at large angle a, el-
lipses. The diameter of the pattern is a function of x, and it is centered at r=0, regardless of the angle of the stage plate 18 or the translation displacement x from the reference point 0. Thus, the interferometer of FIG. 1 cannot be misaligned by erratic motions of the stage plate 18 during a translation.
Referring now to FIG. 4 there is here illustrated a single axis portion of an interferometer which is capable of sensing direction of displacement along a measurement axis. Here a single laser source is shown providing a light source for use in more than two axes of linear measurement. In addition, the interferometer as shown has been modified to provide a sense of direction for a single axial measurement.
In the past direction is typically sensed by correlating or comparing different parts of the fringe pattern. Another method involves the use of parallel beams with one detector in phase quadrature with the other.
Here there is only one possible path from the source to the detector and the fringe pattern broadens until at zero displacement the radius of the first dark ring becomes infinite. Since the fringe size here varies with displacement, it is necessary to divide the input energy into two independent orthogonally polarized beams which may follow coincident paths. If the plane of polarization of the laser is rotated 45 relative to the plane defined by the optical paths, the beam is then equally resolvable into equal vertical and horizontal components which can be separated at the exit pinhole B.
A phase shift is introduced between these components by using a metallic reflecting surface which intersects one optical path and not the other. A metallic reflecting surface as is well known, produces different phase shifts in the orthogonal polarization components on reflection. Thus, the energy linearly polarized at 45 becomes elliptically polarized on reflection from the metallic surface. The amount of phase shift incurred can be varied by changing the angle of incidence.
Referring then to FIG. 4 in detail, the laser 40 is coupled through a focusing lens 41 to a beam splitter 42 which divides the energy into two sources of light useful for more than one measurement axis.
Light energy is transmitted through the beam splitter 42 to a 45 coupling mirror 43 and is focused on a pinhole A in an entrance aperture plate 45. The light emerging from the pinhole A is directed with a spherical wavefront to a beam splitter 46. A portion of the energy is transmitted through the beam splitter 46 along optical path 47 to an end prism 48 which provides two corner reflectors directing the energy to a reflecting surface 49 of the stage plate 50.
The energy portion reflected by the beam splitter is directed to a metallic phase shifting mirror 51 along an optical path 52 to an end prism 53 having two corner reflectors which then direct the energy to a reflecting surface 54 on the stage plate 50. An object 55 to be measured is carried by the movable stage plate 50, which is displaceable along a linear translation axis 56.
A viewing microscope is generally indicated at 57 and includes a fiducial 58 which is imaged on the reference point. The stage plate 50 is formed of glass. Because of the index of refraction of the glass, the fiducial appears to be at the surface of the stage plate in contact with the object 55 to be measured. The object for example may be a photograph. As described above, the reflected energies return to the beam splitter 46 and are directed through the pinhole B in an exit plate 59 through a Wollaston prism 60 which separates the beams in accordance with their planes of polarization along optical paths 61 and 62 to a pair of detectors including light pipes 63 and 64 leading to a pair of photomultiplier tubes 65 and 66. The photomultipliers are coupled through a pair of amplifiers 67 and 68 to a fringe counter 69 which provides an indication of the degree and direction of displacement.
The fringe counter includes means for comparing the phase of the video signals to produce output counts which for example, may be voltage polarized plus or minus corresponding to left or right motions.
A meansfor moving the stage plate is provided by the belt 72 connected to the stage plate which causes the stage plate to slide on surface 70. A motor 73 drives the conveyor belt 72 around a pair of pulleys 74 and 75. Because of the independence of rotation, the stage plate can be moved by hand, if necessary. The motor 73 and belt 72 are provided for convenience, to respond, e.g., to an electrical signal provided by an appropriate programmer.
OPERATION The laser, the aperture plates, the coupling mirrors, the photomultipliers and the coupling prisms, the support surface 70, the motor 73 and the pulleys 74 and 75, the fiducial 58 and its imaging elements are all rigidly coupled together. The stage plate 50 and the object 55 are movable relative to these elements. The fiducial as viewed through the microscope 57 is fixed in space and is, therefore, effectively rigidly coupled to the other elements which are all located in the first frame of reference.
The object 55 is rigidly clamped to the stage plate 50 by means which are not shown in the drawing. A measurement is made between two points on the object 55 by locating the first point at the fiducial and translating until the fiducial is coincident with the second point. While the object is in motion the fringe counter 69 produces at all times an indication of the distance of the first point from the fiducial along a translation measurement axis in the coordinate system of the stage plate as discussed below with reference to FIG. 2. When the second point is reached, a measure of the displacement between the two points along the stage plate or object measurement axis is accurately measured and displayed.
DESCRIPTlON AND EXPLANATION OF THE INTERFEROMETER 1N FlGS. 5-10 Referring now to FIG. t there is here illustrated an isometric view of an interferometer embodying the invention. The interferometer, as shown, is designed to provide accurate measurements of linear distances in a plane. This implies a two axes translation system with an X-axis drive system and a Y-axis drive system. The optical system is rigidly coupled to a table which is, for example, coupled to the earth. The stage plate is free to move in X and Y translation, on the surface of the table.
An X-axis servomotor rides on a track and, for example, has a pinion gear which engages a rack on the table to translate the stage along the X translation axis. The Y-axis drive system includes a pair of tracks tending to restrain the motion of the stage plate parallel to the Y axis tracks. The stage plate, however, is coupled to another track carried by the Y-axis drive system so that it can be translated orthogonally by the Y-axis drive system. The stage plate has two pairs of mutually orthogonal, parallel reflecting surfaces.
A microscope is included to observe the position of the fiducial relative to points to be measured on an object to be measured, such as, for example, a photographic plate. Point to point measurements on a photographic plate are necessary frequently in order to relate such measurements to distances on earth for purposes of aerial survey and reconnaissance work.
in order to obtain separation of the exit reflected energies, the incoming energy from a laser source is plane polarized, for example, with the electric vector vertical. The elements for the optical system of each axis are disposed in a plane at a 45 angle to, for example, the direction of the electric vector in the plane of polarization of the incoming energy. The elements are physically disposed on the surfaces of a truncated pyramid having top and base surfaces parallel to the table and the stage plate. The side surfaces of the truncated pyramid are oriented in planes 45 relative to the plane of the table and hence relative to the electric vector of the input plane polarized light energy.
The fiducial is viewed through an optical system rigidly coupled to the table. A hole in the table enables the projection of the fiducial at the surface of the stage plate which is formed from glass.
A table is fixed to earth and carries a glass stage plate 101 which is translatable with 2 of freedom in X and Y. The stage plate has two pairs of mutually orthogonal, parallel surfaces 102, 103 and 104, 105.
As discussed above the system responds only to translations measured along the orthogonal measurement axes in the stage plate relative to the fiducial. Consequently, the drive system for the stage plate is fairly crude; it need not in any sense involve a precision drive system. Thus, here an X-axis drive motor 106 is coupled to a pinion gear 107 which engages a rack 108 formed in the table 100. The motor 106 travels on a track 109. The stage plate 101 is coupled through a hinge 110 to a track 111 fixed to the motor 106. The motor is translatable along the X-axis while the stage plate is slidable along the track 111 orthogonally to the X-axis.
A Y-axis servomotor 1 12 has a pinion gear which engages a rack 113 fixedly coupled to the table 100. A rail 114 is coupled to a track 115 to restrain the motion in the Y direction parallel to the tracks 113 and 115; the pinion gears are not shown. A viewing aperture 116 is formed in the table 117 to enable the fiducial to be imaged on the surface of the stage plate. A pair of adjustable clamps 117 are used to clamp down an object to be measured, such as a photograph with its emulsion face down on the stage plate.
The X-axis optical system has a pair bf arms 118 and 119 which project opposing light paths to the reflecting surfaces 102 and 103, respectively. The Y-axis optical system has a pair of arms 120 and 121 which project light to the opposing reflecting surfaces of the stage plate 105 and 104, respectively. A microscope 122 is used for viewing the fiducial. A knob 123 is used to change the character of the fiducial for example from a ring, a pair of crosshairs, or an opaque dot; the sizes of the fiducial may be varied in accordance with the size of the object viewed. As in FIGS. 1-4 above, the open arrows indicate the stage plate incident light and the closed arrows indicate the stage plate reflected light.
The optical system assembly is shown in FIG. 6 where a laser housing 124 is coupled to a central housing 125 which includes the truncated pyramid described above. As can be seen from FIG. 6, the X and Y optical paths 126 and 127, respectively lie in planes at 45 relative to the vertical. The intersection of the X-axis optical path 126 and the Y-axis optical path 127 occurs at the fixed reference point 128 for the interferometer. An aperture 129 in the housing 125 corresponds with the aperture 116 in the table to enable imaging of the fiducial effectively at the reference point.
in FIG. 7 a plan view of the interferometer schematically illustrating the basic optical system is shown. In the laser housing a laser 128 projects a light beam on a focusing lens 129 which focuses light on entrance pinholes in the input aperture plates for each of the X and Y optical axis components. The monochromatic, coherent light travels along a central optical axis 131 to a beam splitter 132. The beam splitter 132 is, for example, oriented at an angle relative to the incoming light energy, but its plane is perpendicular to that of the stage plate 101. The beam splitter 132 is located on a truncated prism 133 having opposing surfaces 134 and 13S extending from the base of the pyramid upwardly and inwardly at an angle of 45 relative to the plane of the stage plate. Similarly, surfaces 136 and 137 extend from the base upwardly and inwardly in planes at 45 relative to the stage plate.
The light energy portion transmitted by the beam splitter 132 is directed to the left and up, as shown, to a Y-axis optics housing 155. The reflected light portion from the splitter 132 is directed upwardly and left, as shown, to an X-axis housing 154. The upper parts of housings 154 and 155 have been removed in FIG. 7 for greater clarity. The energy is coupled to a mirror 138 which directs the X-axis energy to focus at a pinhole A, as shown in FIG. 10. and then to an X-axis beam splitter 139 in the X-axis optics housing 154. The plane of the minor 138 is perpendicular to the plane of the stage plate 101. The plane or the beam splitter 139, however, is perpendicular to the plane of the 45 surface 136 and is therefore, oriented at a 45 angle relative to the vertical electric vector in the plane of polarization of the input X-axis light energy portion.
The X-axis energy portion transmitted through the beam splitter 139 extends to the left along the X central optical axis I26 to a coupling mirror 140 and thence to a coupling mirror 141 to the reflecting surface 102. The reflected portion from the splitter 139 is directed to a coupling phase mirror 142 which directs the energy along the X central optical axis 126 to the right, as shown, to a coupling minor 143 and thence to a coupling mirror 144 to the reflecting surface 103.
The Y-axis energy portion is transmitted through the beam splitter 132 to the left, as shown, to a coupling mirror 145 where it is directed to focus on a pinhole A, shown in FIG. 10, and then to a Y-axis beam splitter 146. The reflected portion of the Y-axis energy is directed to a phase coupling mirror 147 and thence, downwardly, as shown along the Y optical axis 127 to a pair of coupling mirrors 148 and 149 and to the reflecting surface 104. The portion of the Y-axis energy which is transmitted through the beam splitter 146 extends along the Y-axis 127 upwardly to a pair of coupling mirrors 150 and 151 and to the reflecting surface 105.
To enhance the clarity of the drawing the rays have not been shown in bundles as was illustrated in FIG. 1,-for example. The light energy in all cases has a spherical wavefront and represents a bundle of energy traveling along the central optical X and Y axes. The returning rayin each case i s onlyfrorn the incident ray normal to the stage plate reflecting surface.
The plane of the X-axis optical path is at an angle of 45 to the stage plate 101 and parallel to the side 136. The planes of the splitter 139 and minors 140-144 are normal to the side 136.
Similarly, the plane of the Y-axis optical path is parallel to the side 135; the planes of the splitter 146 and the mirrors 147-151 are perpendicular to the side 135.
A fiducial image is shown at 152 in the aperture 153 in the pyramid housing. The X-axis optical assembly housing 154 lies on the surface 136 and the Y-axis optical assembly housing 155 lies on the surface 135.
The orientation of the complete X-axis housing 154 is shown in the side view of FIG. 8; the orientation of the complete Y-axis housing 155 is shown in the front view of FIG. 9. For clarity, the coupling optical elements are not shown.
In FIG. 9 a portion of the optical system of the microscope for viewing the flducial is shown. In effect the fiducial is projected, in the absence of the stage plate 101, to the intersection of the X and Y light paths. With the stage plate in place, however, the fiducial appears to be at the upper surface of the stage plate because of the effect of refraction by glass.
A plan view of the Y-axis housing 155 and its components, taken along the lines X-X in FIG. 9, is shown in FIG. 10. The X-axis housing 154 and its components correspond directly with FIG. 10, although disposed on side 136. For clarity, not all elements in FIG. are shown in FIGS. 5-9.
The Y-axis housing 155 includes an entrance aperture plate 156 having a pinhole A and an exit aperture plate 157 having a pinhole B. The Y-axis energy entering the pinhole A comes from the coupling mirror 145 as indicated. It goes to the beam splitter 146 which directs a portion of the Y-axis energy, as noted above, to the phasing coupling mirror 147. The reflected energy portion from the phasing mirror 147 is directed to the coupling mirror 148 as indicated. The transmitted portion from the splitter 146 is directed to the coupling mirror 150 as indicated.
The reflected energy from the stage plate is reflected along an exit path 158 to the exit pinhole B in the plate 157. The reflected energy from the surface 105 comes from the coupling mirror and is reflected by the beam splitter 156 along the exit path 158 with the two reflected energies combine and interfere. The combined reflected energies are transmitted to the pinhole B to a prism 159 which separates orthogonal polarization components to extend along separate orthogonal polarization components to extend along separate paths 160 and 161 to a pair of photomultiplier tubes 162 and 163. A similar description applies to the X-axis exit assembly.
OPERATION The terms X and Y have been used interchangeably to identify the orthogonal measurement axes as well as the orthogonal translation axes. The measurement axes, however, are totally independent of the translation axes. The translation axes X and y roughly correlate with the measurement axes X and Y. Asnoted above, however, the translation axes are taken with respect to one frame of reference while the measurement axes are taken with respect to a different frame of reference, that of the object to be measured. If the stageplate is moved in r and 0, i.e., if the motion of the stageplate is rotational through a pivot arm about a pivot point in the first frame of reference off the stageplate at some distance from the optical axes, and further, is radially extensible relative to the pivot point, only translations along the orthogonal bisecting planes between the mutually orthogonal pairs of parallel reflecting surfaces are measured.
. In operation then a point on the object to be measured, for example a photograph, is made to coincide with the fiducial by viewing the flducial through the microscope 122 and applying electrical signals to the X and Y drive motors until the selected point coincides with the fiducial 52mm time the signals are removed.
The indicated interference count is then set at zero for both the X and Y axes. An electrical signal is then applied to each of the X and Y drive motors 106 and 112 respectively until a second selected point is observed to coincide with the fiducial. At that time the signals are removed and the indication of interference counts produced is noted. A measure of translation in each of the X and Y measurement axes is obtained from which the lineal distance between the two points is readily derived.
The photograph need not be carefully aligned. It is merely placed with the emulsion side down on the stage plate and the clamps 117 are snapped down to hold it in place.
Referring now to FIG. 11, there is here illustrated a positioning apparatus embodying the invention applicable, for example, for positioning a planar piece of work relative to a drill press. Here the problem is to position the work accurately with respect to the drill bit in a programmed sequence. Preprogrammed tape supplies the indicia for each hold to be drilled. In the simplest case for a single spindle the programming is straight-forward and serial. Since the XY information is applied simultaneously the drive system moves the planar work piece in both X and Y at the same time. If the piece reaches the X position coordinate first, it ceases to move in X and is simply driven along the Y axis to the desired point.
As a positioning apparatus, the stage plate becomes the workpiece and the fiducial becomes the tool. Using the two axes interferometer of FIGS. 5-10, the outputs of each axis in phasequadrature channels A and B are each applied to a phase sensing logic circuit. The logic circuit produces count pulses coupled to an up-down" counter, for-example, which produces an actual count of interference fringes indicative of the instantaneous position of a point on the workpiece relative to the tool. The pulses either add to or subtract from the count indicated. A desired location is preprogrammed and coupled to registers for each axis. The registers and the counters are coupled to a subtractor. The output of the subtractor is coupled to a digital to analogue converter which produces an error signal in each axis to drive its respective servomotor. The apparatus servos around the desired position until it comes to rest. At that time the operation is completed, preferably by moving the workpiece along the Z axis until the cut is completed.
In detail then, the interferometer 200 has an X axis drive servomotor 201 which translates the stage plate or the workpiece along an X translation axis and a Y axis drive servo motor 202 drives the work piece along the Y translation. Here the tool is fixed in position and the work piece moves. Conversely, the tool may move and the workpiece be fixed in position. Note that the fiducial can be a pair of crossed hairs in a microscope, an engraving tool, a light beam, a laser, tool bit, scribe, pen or drillpoint, etc.
The output of the interferometer are the X and Y signals from the photoelectric detectors where the phase of channel A is in quadrature with channel B for each axis. The signals are coupled to a phase sensing logic circuit 203 which determines the direction of the motion either plus or minus X. If the output indicates a positive going motion, pulses are coupled to the plus input of the X counter. Each pulse represents a detector fringe which represents one-fourth of a wavelength at the frequency of the light source. If the output of the phase sensing circuit is negative, the counts are subtracted from the cumulative total in the counter. If it is going in the plus direction, the pulses add.
This count is then compared with instructions derived from the tape programmer 204 coupled to an input register 206 for X desired position and an input register 207 for Y desired position. The X counter 208 is then coupled to a subtractor 209 which in turn is coupled to an X-axis digital-to-aiialbg converter 210 to produce an error signal which is coupled to the X-axis drive servo motor. The workpiece or stage plate continues to move in a position or negative X direction until the error signal is reduced to 0, i.e., less than a quarter wavelength, for example, 0. l microns.
Similarly, the output of the Y-axis photoelectric detectors in the interferometer are coupled to a pair of quadrature phased channels A and B. A Y-axis phase sensing circuit 211 produces an indication of direction either plus or minus along the Y-axis. The circuit 211 is coupled to a Y-axis counter 212 which adds positive counts and subtracts negative counts.
The Y-axis counter 212 and the Y-axis register 207 are coupled to a Y-axis subtractor 213 which produces Y-axis difference signals. The difference signals are coupled to a digitalto-analogue converter 214 which is coupled to the Y-axis servomotor 202.
While relative translations between the workpiece and the tool take place in more than one direction, its application to a broad range of such tools is clear.
A milling machine, for example, requires continuous measurement of position in order to provide continuous error correction. Such a machine is schematically illustrated in FIG. 12.
Referring then to FIG. 12, there is here illustrated a milling machine embodying the invention. The milling machine here is another application of the apparatus in FIG. 11.
A base yoke 225 carries a motor 226 and a spindle head 227. The spindle head carries the interferometer optical source and assembly. Extending from the spindle is shown a pair of optical arms 228 and 229 defining the Y-axis optical path 230. An X-axis motor 231 and Y-axis motor 232 drive lead screws which position a workpiece 239 clamped in a table having two pairs of mutually orthogonal reflecting surfaces. Here the Y-axis reflecting surfaces 234 and 235 are shown. The X-axis motor positions a table carrying the Y-axis motor and table along the X translation axis, into the plane of the drawing. The Y-axis motor is affixed to the X translation table and positions the Y translation table relative thereto, thereby positioning the workpiece in X and Y continuously to control the direction of the cut with great accuracy. A Z-axis motor positions the table to engage the cutter to a desired depth. The
cutting end of the tool is positioned at the reference point 0 and is, in fact, the fiducial.
The interferometer is coupled to a control circuit where the functions described with reference to FIG. 11 are included. X and Y position signals are coupled to the circuit 236 which produces X and Y error signals coupled to the motors 231 and 232 respectively, to maintain a continuous, accurate desired cutting path.
Referring now to FIG. 13, there is here illustrated a modification of the embodiment in FIG. 1.
From the analysis of FIG. 2, it is clear that the reflecting surface may be outside the sources; i.e., the light source may be located between reflecting surfaces which face each other and reflect opposing rays of light.
a. An interferometer is shown having a stage plate with reflecting surfaces rigidly coupled together and facing each other with the light source in between. A laser beam of monochromatic, coherent light is focused on a pinhole A in an entrance aperture plate. The spherical wavefront light produced from the pinhole is transmitted to a beam splitter. The beam splitter reflects an energy portion of a coupling mirror and one of the pair of parallel reflecting surfaces. The portion transmitted by the beam splitter is directed by coupling mirrors to an opposing path to the other reflecting surface, both paths incident upon the reflecting surfaces being colinear.
In operation, the interferometer of FIG. 13 is similar to that in FIG. I. The flducial is again located at the center point between the apparent optical sources.
Thus a laser 300 produces a light beam which is focused by a lens 301 on a pinhole A in plate 302. The light is transmitted to a beam splitter 303 which reflects a portion to a coupling mirror 304 and thence to the left, as shown, to a reflecting surface 305. The reflecting surface 305 is rigidly coupled to an opposing parallel reflecting surface 306, the two reflecting surfaces facing each other and reflecting light inwardly.
The light energy portion transmitted by the beam splitter 303 is directed by a pair of coupling mirrors 307 and 308 to the reflecting surface 306. The path 309 to the surface 306 and the path 310 to the surface 305 are colinear but opposing in direction. A stage plate 311 presents a rigid body with reflecting surfaces 305 and 306.
The reflected energies are directed back through the coupling mirrors backwards through the beam splitter 303 through exit pinhole B in the exit aperture plate 313 to the detector 312.
As illustrated in FIG. 13, the light source is disposed between the reflecting surfaces. The fiducial is located, in accordance with the analysis of FIG. 2, at the center point between the two apparent sources. A translation along a measurement axis in the coordinate system of the stage plate is the distance along the normal from the fiducial to the bisecting plane.
This modification of the embodiment in FIG. 1 is particularly useful for machine tool applications and other positioning and control devices because the long optical arms are not necessary. The interferometer head can be made very small and more than one interferometer head can be used to locate a number of points on the stage plate simultaneously.
The fiducial can always be determined physically, in accordance with the analysis of FIG. 2 and compensating for various phase and transmission changes which take place due to elements in the system, to within 0.001 inches. Such an error, however, produces a translation error less than 10" inches.
The term paralleP as used herein means that degree of parallelism consistent with the degree of accuracy required. A relatively large variation from a true parallel condition produces translation errors which are relatively negligible. For example, lack of parallelism of the order of 10 seconds of arc
|Cited Patent
|Filing date
|Publication date
|May 4, 1937
|Mar 21, 1939
|Ewart Williams William
|Optical interferometer
|Oct 12, 1946
|Oct 24, 1950
|American Cyanamid Co
|Diffraction grating ruling engine
|Mar 30, 1955
|Jul 1, 1958
|Perkin Elmer Corp
|Oct 21, 1964
|Nov 5, 1968
|Cutler Hammer Inc
|Gauging interferometer systems
|Citing Patent
|Filing date
|Publication date
|Feb 8, 1974
|Mar 2, 1976
|The Gerber Scientific Instrument Company
|Work locating system and method with temperature and other compensation capabilities
|Apr 2, 1975
|Nov 1, 1977
|Ludman Jacques E
|Interferometer optical system
|Apr 30, 1979
|Jul 21, 1981
|Varian Associates, Inc.
|X-Y Work table
|Aug 15, 2002
|Aug 30, 2005
|Black & Decker, Inc.
|Optical alignment system for power tool
|Mar 25, 2003
|Sep 13, 2005
|Pioneer Corporation
|Laser distance measuring system and laser distance measuring method
|Dec 23, 2003
|Jul 11, 2006
|Black & Decker Inc.
|Level apparatus
|Nov 23, 2004
|Nov 21, 2006
|Black & Decker Inc.
|Riving knife assembly for a dual bevel table saw
|Oct 6, 2004
|Jul 17, 2007
|Black & Decker Inc.
|Gauge for use with power tools
|Dec 29, 2004
|Nov 6, 2007
|Black & Decker Inc.
|System for rapidly stopping a spinning table saw blade
|Jul 31, 2003
|Mar 18, 2008
|Black & Decker Inc.
|Power tool control system user interface
|Apr 10, 2002
|Apr 15, 2008
|Carl Zeiss Ag
|System and method for determining a position or/and orientation of two objects relative to each other as well as beam guiding arrangement, interferometer arrangement and device for changing an optical path length for use in such a system and method
|Apr 23, 2004
|Apr 15, 2008
|Black & Decker Inc.
|Measurement and alignment device including a display system
|Oct 1, 2004
|May 6, 2008
|Black & Decker Inc.
|Drill press
|Apr 19, 2011
|Black & Decker Inc.
|Cutter with optical alignment system
|Aug 23, 2011
|Chang Type Industrial Company
|Power tool control system
|Apr 1, 2009
|Jan 7, 2014
|Robert Bosch Gmbh
|Interferometric system and method for adjusting a path difference
|Apr 16, 2009
|Dec 16, 2014
|Robert Bosch Gmbh
|Optical system for illuminating a measured object and interferometric system for measuring surfaces of a measured object
|Aug 15, 2002
|Feb 19, 2004
|Garcia Jaime E.
|Optical alignment system for power tool
|Mar 25, 2003
|Feb 26, 2004
|Pioneer Corporation
|Laser distance measuring system and laser distance measuring method
|Nov 26, 2003
|May 26, 2005
|Scimed Life Systems, Inc.
|Rotating measuring device
|Apr 16, 2009
|May 26, 2011
|Matthias Fleischer
|Official system for illuminating a measured object and interferometric system for measuring surfaces of a measured object
|Apr 1, 2009
|Jun 2, 2011
|Matthias Fleischer
|Interferometric system and method for adjusting a path difference
|Oct 6, 2011
|Fujifilm Corporation
|Aspheric surface measuring apparatus
|May 10, 2011
|Nov 15, 2012
|Fraunhofer-Gesellschaft zur F�rderung der angewandten Forschung e.V.
|Optical arrangement for laser interference structuring of sample, has positioning mirrors which are arranged for reflecting beams on common target point so that optical path length of beams between beam splitter and common target is same
|May 8, 1989
|Nov 15, 1989
|Hewlett-Packard Company
|Method for improving performance of a laser interferometer in the presence of wavefront distortion
|Apr 12, 2002
|Oct 23, 2002
|Carl Zeiss
|System and method for determining the position or/and the orientation of two objects relative to each other, as well as beam guidance device, interferometer system and device for modifying the optical pathlength for use in such a system and method
|Apr 16, 2009
|Nov 5, 2009
|Robert Bosch Gmbh
|Optical arrangement for illuminating a measured object, and interferometric arrangement for measuring surfaces of a measured object
|U.S. Classification
|International Classification
|Cooperative Classification
|European Classification


text:
117 Cherry St. Seattle, Wa. 98104
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Bewitched, Bothered, and Biscotti: A Magical Bakery Mystery (Mass Market Paperbound)
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text:
"For a senator to be modest is a unique thing. But when Sen. Dodd says he's only been on the job for a few days and he's just learning, that is a modest statement," said John Fithian, who heads the National Association of Theatre Owners.
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Dodd has been walking into meetings quoting figures on the number of domestic movie screens and laying out issues facing the theatrical business in Europe, "a tour de force for a guy who's got, like he said, nine days experience on the job," Fithian said.


text:
1945 Northwest 75th Street
Miami, Florida, 33147
Commute to Downtown West Little River
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1945 Northwest 75th Street has a Walk Score of 67 out of 100. This location is Somewhat Walkable so some errands can be accomplished on foot.
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This location is in the city of Miami, FL. Miami has an average Walk Score of 78 and has 399,457 residents.


text:
Gilmore Girls 2006 | TV Show Watchlist
Season 6, Episode 21 Driving Miss Gilmore
First Aired: May 2, 2006
Logan comes home from the hospital and is cared for by an overprotective Rory; Liz has big news for Luke; Emily has LASIK eye surgery, so Lorelai has to serve as her chauffeur; Rory is upset by a statement Logan's dad made about her in an interview in the Wall Street Journal; Jackson discovers that former employees planted marijuana in one of his fields, and he and Sookie try to dispose of it.
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text:
The Chris and Marli Tilley Scholarship, established by a local family in the town of Stawell, supports one graduate from local high school every year so they can attend university.
Topics: continuing-education, rural-youth, charities-and-community-organisations, regional, stawell-3380
Several residents in Victoria's Wimmera and Mallee have been recognised in the Queen's Birthday honours list.
Topics: awards-and-prizes, royal-and-imperial-matters, stawell-3380, horsham-3400, mildura-3500
Momentum is building behind a regional western Victorian push for local governments to get an increased share of the tax dollar.
Topics: local-government, activism-and-lobbying, tax, stawell-3380, horsham-3400
A former Victoria Police prosecutor will spend almost three years behind bars for a string of domestic violence offences.
Topics: police, crime, domestic-violence, courts-and-trials, ballarat-3350, ararat-3377, stawell-3380, horsham-3400, warrnambool-3280
Victoria's mining regulator says elevated levels of arsenic have been detected in dust samples that blew offsite from the Stawell Gold Mine.
Topics: mining-environmental-issues, mining-industry, environmental-management, air-pollution, stawell-3380, douglas-3401, horsham-3400
Posted| Updated
An Ararat businessman offers a lifeline to the historic Seppelt's winery in the tiny Victorian town of Great Western, just months before the cellar door was due to close.
Topics: agricultural-crops, rural, great-western-3377, stawell-3380, ararat-3377
GWM Water has lifted stage two water restrictions in Stawell in western Victoria.
Topics: water-management, water, water-supply, stawell-3380, horsham-3400
Posted| Updated
In America's deep south they call them cotillions. But in Victoria's wild west, it has just always been the deb.
Topics: human-interest, offbeat, stawell-3380, vic
The Victorian Roads Minister says he cannot confirm when funding will be committed to finalise the Western Highway duplication between Ballarat and Stawell.
Topics: urban-development-and-planning, federal---state-issues, stawell-3380, ballarat-3350, buangor-3375
Posted| Updated
Stawell residents have expressed concern about large plumes of dust thought to be coming from the Stawell Gold Mine's tailings storage facility in western Victoria.
Topics: air-pollution, states-and-territories, environmental-management, environment, stawell-3380, horsham-3400
Footage taken by a Stawell resident shows dust allegedly blowing off the Stawell Gold Mine's tailings dam, which is known to contain toxic chemicals.
Topics: mining-rural, mining-environmental-issues, rural, stawell-3380
The operator of the Stawell gold mine is hopeful cooperation with the Victorian Government during a recent environmental audit will help with future mining licence applications.
Topics: mining-industry, mining-environmental-issues, states-and-territories, gold, stawell-3380, horsham-3400
The author of an environmental review of the Stawell Gold Mine says he would like to see the operators go beyond the minimum legal requirements.
Topics: mining-environmental-issues, mining-industry, states-and-territories, gold, environmental-management, stawell-3380, horsham-3400
The boss of the Northern Grampians Shire is expected to be installed on Wednesday night as Ballarat council's new chief executive.
Topics: local-government, ballarat-3350, stawell-3380
The coach of Stawell Gift women's final winner Talia Martin rejects any suggestion either of them have done anything wrong, after the 15-year-old was fined $2,000 over a dramatic improvement in form.
Topics: athletics, sport, stawell-3380
Fifteen-year-old Victorian sprinter Talia Martin has staged has upset to become the youngest woman to win Australia's richest foot race, the Women's Gift in Stawell.
Topics: athletics, sport, stawell-3380
Posted| Updated
A dramatic improvement in form by the winner of the Stawell Gift women's final is "not a good look" and may lead to a review of rule changes in the $40,000 race, the Victorian Athletic League says.
Topics: sport, athletics, stawell-3380
Fifteen-year-old Victorian sprinter Talia Martin has staged an upset to become the youngest woman to win Australia's richest foot race, the Stawell Gift.
Topics: athletics, sport, stawell-3380
Posted| Updated
Fifteen-year-old Victorian sprinter Talia Martin stages an upset to become the youngest woman to win the Women's Gift in Stawell, but is fined $2,000 for "inconsistent running".
Topics: sport, athletics, stawell-3380
Posted| Updated
Australia's fastest women's sprinter Melissa Breen says she is ready for the final day of competition in the Stawell Gift, the nation's richest race.
Topics: athletics, sport, stawell-3380, vic
The operator of the Melbourne to Adelaide Overland rail service says a $10 million funding commitment from the Victorian Government means passengers can now book past June.
Topics: rail-transport, states-and-territories, vic, stawell-3380, horsham-3400, nhill-3418, mildura-3500, dimboola-3414, ararat-3377
Posted| Updated
The future of the Overland train between Adelaide and Melbourne is secure until at least the end of 2018 with Victoria agreeing to help fund the service.
Topics: states-and-territories, government-and-politics, community-and-society, adelaide-5000, sa, melbourne-3000, vic, stawell-3380, ararat-3377, horsham-3400, mildura-3500, ballarat-3350, dimboola-3414, nhill-3418, warrnambool-3280, mount-gambier-5290
The future of the only passenger rail link between Adelaide and Melbourne is unclear due to uncertainty over its funding.
Topics: rail-transport, states-and-territories, federal---state-issues, stawell-3380, horsham-3400, ararat-3377, dimboola-3414, nhill-3418, melbourne-3000
The Environment Protection Authority (EPA) says it is satisfied Stawell Gold's leaking tailings dam poses no risks to public health or safety.
Topics: mining-industry, mining-environmental-issues, environmental-management, water-pollution, water, water-management, stawell-3380, horsham-3400
Posted| Updated
Two men have died in separate incidents in Victoria overnight, including a 53-year-old man shot dead in a house in Landsborough in the state's west.
Topics: murder-and-manslaughter, crime, law-crime-and-justice, landsborough-3384, clayton-3168, stawell-3380