Deflecting roller for sensing the distribution of stress along the roller

• US 5,629,487 A
• Filed: 03/19/1996
• Issued: 05/13/1997
• Est. Priority Date: 10/30/1992
• Status: Expired due to Term

• Current Assignee: Betriebsforschungsinstitut Vdeh-Institute Fr Angewandte Forschung
• Original Assignee: Betriebsforschungsinstitut Vdeh-Institute Fr Angewandte Forschung
• Inventors: Neuschutz, Ebernhard, Mucke, Gert, Thies, Helmut
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US08/616,490
• Time in Patent Office: 420 Days
• Field of Search: 73/159, 73/790, 73/818, 73/829, 73/858, 73/862.391, 73/862.42, 73/862.44, 73/862.453, 73/862.471, 73/862.473, 73/862.49 , 73/.55
• US Class Current: 73/818
• CPC Class Codes: B21B 38/02 for measuring flatness or profile of strips
• CPC Class Codes: G01L 5/045 for measuring the tension across the width of a band-shaped flexible member measuring flatness G01B

Abstract

A deflecting roller for sensing the distribution of stress along the roller while the roller deflects a strip of sheet material, and in particular, a deflecting roller having a plurality of stress sensors disposed around the roller such that the stress sensors sense the radially acting force on the roller, without contributing any interfering forces thereto. The roller has a plurality of measuring locations defined about the circumference of the roller. Each measurement location includes a recess in the roller; a stress-responsive sensor disposed in the recess; and a sensor cover positioned within the recess so as to cover the stress-responsive sensor. The sensor cover has the same cross sectional shape as the recess so that the sensor cover is guided by the wall of the recess for radial movement with respect to the roller. The sensor cover does not rest on a shoulder in the recess. Instead, an inside surface of the sensor cover bears against one end of the stress-responsive sensor, while the outside surface of the sensor cover is convex to match the circumferential shape of the roller. In operation, when the measuring roller acts to deflect a piece of sheet metal, the sensor cover is forced further into the recess by the piece of sheet metal, and as a result, the sensor cover compresses the stress-responsive sensor between the bottom of the recess and the inside surface of the sensor cover.

Claims

1. An apparatus for sensing distribution of stress along a deflecting roller while said roller deflects a strip of sheet material, including a substantially cylindrical roller body having a circumferential surface, said apparatus comprising:

a radially extending recess in said cylindrical roller body, having a top portion which opens to the circumferential surface of said cylindrical roller body, a bottom defined at the radially innermost point of the recess, and a side wall defined therebetween;

a stress-responsive sensor disposed completely within said radially extending recess, the stress-responsive sensor being circumferentially surrounded by the side wall of said recess and spaced apart from said side wall;

a sensor cover having a cross sectional shape corresponding to that of the radially extending recess, said sensor cover being arranged in the top portion of said recess, for only radial movement with respect to the circumferential surface of the cylindrical roller body, wherein said sensor cover is separated from the side wall of the recess by a gap which circumferentially surrounds the sensor cover and prevents interfering forces from being imparted against the sensor by the sensor cover.

2. The apparatus of claim 1, wherein a convex part of said sensor cover extends outside of said recess in a manner that conforms with the shape of the circumferential surface of said cylindrical roller body.

3. The apparatus of claim 1, wherein said radially extending recess is cylindrical, and said sensor cover has a cylindrical shape that fits within said recess.

4. The apparatus of claim 1, wherein said cylindrical roller body and said sensor cover are comprised of the same material.

5. The apparatus of claim 1, wherein said cylindrical roller body and said sensor cover are comprised of materials with the same strength, elasticity, wear resistance, and thermal coefficient of expansion.

6. The apparatus of claim 1, wherein said cylindrical roller body and said sensor cover are machined together so that a convex part of said sensor cover extends outside of said recess in a manner that conforms exactly with the shape of the circumferential surface of said cylindrical roller body.

7. The apparatus of claim 1, wherein said stress-responsive sensor has a tubular shape.

8. The apparatus of claim 1, and further comprising a groove disposed circumferentially around the sensor cover and an O-ring disposed in said groove, between the sensor cover and the wall of said recess.

9. The apparatus of claim 1, and further comprising a groove disposed circumferentially around the side wall of said recess, and an O-ring disposed in said groove, between the sensor cover and the side wall of said recess.

10. The apparatus of claim 1, wherein said gap is 0.01 to 0.05 millimeters wide.

11. The apparatus of claim 10, wherein said sensor cover responds to being heated to approximately 100 degrees C. by closing said gap, and when subsequently cooled, contracts to redefine said gap in a uniformly concentric manner about the sensor cover.

12. The apparatus of claim 1, wherein said radially extending recess is cylindrical, and said sensor cover has a cylindrical shape that fits within said recess, said sensor cover having a portion of increased diameter disposed at the top of said recess.

13. The apparatus of claim 12, and further comprising a groove disposed adjacent said portion of increased diameter and circumferentially around the side wall of said recess, and an O-ring disposed in said groove between the sensor cover and the side wall of said recess.

14. The apparatus of claim 1, wherein said stress-responsive sensor has a tubular shape, and wherein said sensor cover further comprises a shaft portion extending radially inward with respect to the cylindrical roller body, said shaft portion passing through said stress-responsive sensor, and through the bottom of said recess, and engaging a locking mechanism in the cylindrical roller body, which locking mechanism restricts the radial movement of said sensor cover.

15. The apparatus of claim 1, wherein said stress-responsive sensor has a tubular shape, and further comprising a stay bolt extending radially outward with respect to the cylindrical roller body, said stay bolt extending through the bottom of said recess, through said stress-responsive sensor, and partially through said sensor cover for engagement therewith, said stay bolt also passing through a locking mechanism in the cylindrical roller body, which locking mechanism restricts the radial movement of said sensor cover by restricting the radial movement of the stay bolt.

16. The apparatus of claim 1, wherein said stress-responsive sensor has a tubular shape, and further comprising a tightening bolt disposed centrally through said sensor cover and extending radially inward with respect to said cylindrical roller body, said tightening bolt passing through said sensor cover, through said stress-responsive sensor, and through the bottom of said recess for engagement with a locking mechanism in the cylindrical roller body, which locking mechanism restricts the radial movement of the sensor cover by restricting the radial movement of the tightening bolt.

17. The apparatus of claim 1, and further comprising a measuring cable for transmitting signals generated by said stress-responsive sensor, and a radial bore for accommodating said measuring cable, said radial bore extending through the bottom of the recess and radially inward with respect to the cylindrical roller body.

18. The apparatus of claim 1, wherein said stress-responsive sensor comprises a quartz piezo sensor.

19. The apparatus of claim 1, and further comprising a measuring cable for transmitting signals generated by said stress-responsive sensor, and an axial bore for accommodating said measuring cable, said axial bore extending through the side wall of the recess and axially with respect to the cylindrical roller body.

20. The apparatus of claim 19, wherein a plurality of said measuring cables from a plurality of said stress-responsive sensors, are accommodated within one of the axial bores.

21. The apparatus of claim 20, wherein said plurality of measuring cables branch out from said one of the axial bores at predetermined axial positions where said stress-responsive sensors are located along said cylindrical roller body.

22. The apparatus of claim 1, wherein said radially extending recess is cylindrical, said side wall of the recess having a circumferential groove which partially accommodates an O-ring such that the O-ring is maintained at the groove and projects out therefrom so as to tighten said gap between them side wall of the recess and the sensor cover.

23. The apparatus of claim 1, wherein said radially extending recess is cylindrical, and wherein said sensor cover has a main portion and a portion of increased diameter with respect to the main portion thus defining a shoulder, said portion of increased diameter being circumferentially separated from the side wall of the recess by said gap, said main portion having a circumferential groove which partially accommodates an O-ring such that the O-ring is maintained at the groove and projects out therefrom so as to engage the side wall of said recess.

24. The apparatus of claim 1, wherein said deflecting roller and said sensor cover are constructed from materials having substantially the same strength and properties of thermal expansion.