Method for making torsional sensing load cells

• US 6,571,456 B2
• Filed: 05/01/2001
• Issued: 06/03/2003
• Est. Priority Date: 07/12/1999
• Status: Expired due to Fees

• Current Assignee: GAGETEK, LLC
• Original Assignee: Gagetek Technologies Holdings Company
• Inventors: Bruns, Robert W.
• Primary Examiner(s): Eley, Timothy V.
• Assistant Examiner(s): Grant, Alvin J.
• Application Number:
  US09/847,008
• Publication Number:
  US 20010027687A1
• Time in Patent Office: 763 Days
• Field of Search: 296/211, 29/253.5, 295/94, 298/41, 298/57, 298/58
• US Class Current: 29/621.1
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015
• CPC Class Codes: G01L 3/14 wherein the torque-transmitting element is other than a torsionally-flexible shaft
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/49103 Strain gauge making
• CPC Class Codes: Y10T 29/49146 with encapsulating, e.g., potting, etc.
• CPC Class Codes: Y10T 29/49174 Assembling terminal to elongated conductor

Abstract

A method for manufacturing a torsional sensing load cell includes providing a member configured to sense torsion. Strain gauges are provided on selected portions of the member, such that torsion force produced an applied load is detected by the strain gauges.

Claims

1. A method of making a load cell comprising:

forming a beam into a shape having a curved section with opposed segments of said beam forming ends of said curved section in torsional capability toward each other, and forming strain gauges on said opposed segments, wherein said load cell generally is U-shaped.

2. The method of claim 1 wherein said forming includes depositing insulative layers onto said opposed segments, then defining active areas on said insulative layers, then masking and etching strain gauge patterns on said active areas, and then covering said strain gauge patterns with protective layers.

3. The method of claim 2 further defined by making electrical contact pads in the strain gauge pattern for abutting electrical contact with conductors.

4. The method of claim 1 wherein said forming includes, for each of said segments, depositing an insulative layer and printing a strain gauge pattern using conductive ink.

5. The method of claim 4 wherein said forming further includes printing a circuit pattern using said conductive ink.

6. A method for producing a load cell comprising:

providing a cell having a first member, a second member, and a third member, said third member integrally coupling together said first and second members in a manner to form a generally U-shaped structure to produce torsional stress in said first, second, and third members in response to a first force applied to said first member and a second force applied to said second member;

disposing a first force transducer upon said third member proximate said first member, to detect torsional stress in said first member; and

disposing a second force transducer upon said third member proximate said second member to detect torsional stress in said second member,

each of said steps of disposing including forming a strain gauge and one or more circuit patterns to electrically connect said first and second force transducers.

7. The method of claim 6 wherein each of said steps of disposing further includes the use of conductive inks to form said strain gauges and said circuit patterns.

8. The method of claim 6 wherein each of said steps of disposing further includes a deposition technique to form said strain gauges and said circuit patterns.

9. The method of claim 6 further including encapsulating said first and second force transducers.

10. A method for manufacturing a load cell comprising:

forming a generally U-shaped member having a main body portion and first and second extending portions extending away from said main body portion; and

forming a first and second transducers respectively along said first and second extending portions and proximate said main body portion,

said first and second extending portions having load bearing regions disposed in a manner that torsional stress is produced through said first and second extending portions when said load bearing regions are loaded.

11. The method of claim 10 wherein said first and second transducers are formed with conductive inks.

12. The method of claim 10 wherein said first and second transducers are formed using deposition and etch processing.

13. A method of making a load cell comprising:

forming a beam into a shape having a curved section with opposed segments of said beam forming ends of said curved section in torsional capability toward each other, and forming strain gauges on said opposed segments using conductive inks, wherein opposed forces applied to said opposed segments produces torsion in said curved section, said curved section being generally U-shaped.

14. The method of claim 13 wherein said opposed sections are substantially coplanar.

15. The method of claim 13 wherein said load cell is in the shape of a tuning fork.