Cleaning apparatus for light tube in an optical inspection system

United States Patent m

Wilbur et al.

[54] CLEANING APPARATUS FOR LIGHT TUBE IN AN OPTICAL INSPECTION SYSTEM

[75] Inventors: John H. Wilbur; Calvin G. Gray, both of Medford, Oreg.

[73] Assignee: Simco/Ramic Corporation, Medford, Oreg.

[21] Appl. No.: 98,646

[22] Filed: Jul. 28,1993

[51] Int. Cl.« G02B 27/00; F21V 33/00

[52] U.S. Q 359/508; 15/256.5

[58] Field of Search 359/508, 507; 15/256.5,

15/256.51

[56] References Cited

U.S. PATENT DOCUMENTS

3,145,249 8/1964 Meltzer 359/508

3,495,366 2/1970 Allen 359/508

4,285,090 8/1981 Jurkowski 15/256.51

5,068,770 11/1991 Baziuk 362/61

5,161,055 11/1992 Blechschmidt 359/508

OTHER PUBLICATIONS

Key Technology, Inc., brochure entitled "ColorSort (g) II: A Profile in Productivity" (1991).

Primary Examiner—Jon W. Henry

US005402264A

[ii] Patent Number: 5,402,264 [45] Date of Patent: Mar. 28,1995

Attorney, Agent, or Firm—Stoel Rives Boley Jones & Grey

[57] ABSTRACT

An optical inspection system (10) has an inspection region (20) through which articles (12) pass and are illuminated by illumination (22) provided by an illumination source (30). The source is shielded from the inspection region by a protective shield or tube (32) transmissive of the illumination. A cleaning element (42), such as a plastic string, contacts a major surface (45) of the tube and dislodges contaminants (63) from the major surface as the tube rotates. The cleaning element has an active portion (60) held in contact with the major surface by tension in the cleaning element applied at tension locations (56, 58). The cleaning element describes part of a spiral or helix; it preferably occupies less than about 360 degrees, more preferably between about 30 and about 270 degrees, and still more preferably about 120 to about 240 degrees, of arc measured about the axis of the tube. The cleaning element flexes significantly under compression but remains taut under tension; it may be a monofilament or of woven construction; it has a maximum cross-sectional dimension De that is much less than the maximum cross-sectional dimension Drof the tube.

21 Claims, 3 Drawing Sheets

48