Sensing element for measuring loads

• US 6,082,203 A
• Filed: 05/15/1998
• Issued: 07/04/2000
• Est. Priority Date: 09/15/1995
• Status: Expired due to Term

• Current Assignee: Savcor Group Limited (Fluence Corp. Ltd.)
• Original Assignee: Marja-Liisa Koivisto
• Inventors: Sundqvist, Jari, Koivisto, Vesa
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): THOMPSON, JEWEL VERGIE
• Application Number:
  US09/029,998
• Time in Patent Office: 781 Days
• Field of Search: 73/862.627, 73/862.632, 73/862.635, 73/431, 73/866.5, 73/88.5
• US Class Current: 73/862.627
• CPC Class Codes: G01B 7/16 for measuring the deformation in a solid, e.g. by resistance strain gauge
• CPC Class Codes: G01G 19/12 having electrical weight-sensitive devices
• CPC Class Codes: G01L 1/2231 the supports being disc- or ring-shaped, adapted for measuring a force along a single direction
• CPC Class Codes: G01L 1/2256 involving digital counting

Abstract

The invention relates to a sensing element for measuring loads. According to the invention, the sensing element commprises: a strain transducer unit (1) measuring the strain in a structure, including a strain transducer element, such as a strain gauge element (6); and a protecting shell (2) inside which the strain transducer unit (1) is fitted and which protecting shell includes: a base plate (3), on top of which the strain transducer unit (1) is attached; and a protecting hood (4) which is fitted around the strain transducer unit (1), on top of the base plate (3). The protecting hood (4) is most advantageously filled with protecting material (5), such as silicon.

Claims

1. A sensing element for measuring loads comprising:

a strain transducer unit including a strain transducer element;

a base plate on which said strain transducer unit is mounted and by which said strain transducer unit can be fixed to a measuring point of a structure such that the base plate does not move relative to the structure when a load is being measured, said base plate lies in a plane and is symmetrical about at least three axes extending within said plane and through a center of the base plate, said base plate including a middle region to which said strain transducer element is attached and an outer edge; and

a protecting hood mounted over said strain transducer unit and on an upper surface of said base plate so that said protecting hood encloses said strain transducer unit and a periphery of said protecting hood is spaced inwardly toward the center of the said base plate from said outer edge of said base plate.

2. A sensing element according to claim 1 wherein said strain transducer element includes a strain gage element.

3. A sensing element according to claim 1 wherein the base plate is a square plate.

4. A sensing element according to claim 1 wherein the base plate is octagonal in shape.

5. A sensing element according to claim 1 wherein the base plate is a round disc.

6. A sensing element according to claim 1 wherein the base plate and the protecting hood include a metal sheet.

7. A sensing element according to claim 6 wherein said metal sheet is a steel sheet.

8. A sensing element according to claim 1 wherein a volume within the protecting hood contains a material for protecting said strain transducer element.

9. A sensing element according to claim 8 wherein the protecting material includes a resilient silicon material.

10. A sensing element according to claim 9 wherein the protecting hood is secured to said base plate by the resilient material.

11. A sensing element according to claim 1 wherein the strain transducer unit further includes an A/D converter and a data processing unit for converting an analog measuring message to digital form and for pretreating measuring data.

12. A sensing element according to claim 1 wherein said data processing unit includes a microprocessor.

13. A sensing element according to claim 1 wherein the strain transducer unit comprises a circuit board on which said strain transducer element is attached.

14. A sensing element according to claim 13 wherein the circuit board is a round disc made of a thin plastic material attached in the middle region of the base plate;

and wherein the strain transducer element is attached in the middle of the circuit board.

15. A sensing element according to claim 14 wherein the strain transducer unit comprises a connector to which the strain transducer element is connected, and wherein said strain transducer element is capable of being connected to external devices.

16. A sensing element according to claim 14 wherein the base plate is a round disc.

17. A sensing element according to claim 13 wherein the strain transducer unit comprises strain gauge elements arranged to form an isosceles triangle.

18. A sensing element according to claim 13 wherein the strain transducer unit further includes an A/D converter and a data processing unit for converting an analog measuring message to digital form and for pretreating measuring data.

19. A sensing element for measuring loads comprising:

a strain transducer unit including a strain transducer element having a strain gage element;

a base plate on which the strain transducer unit is mounted and by which said strain transducer unit can be fixed to a measuring point of a structure such that the base plate does not move relative to the structure when a load is being measured, wherein the base plate lies substantially in a plane and is symmetrical about at least three axes extending within said plane and through a center of the base plate, said base plate includes a middle region to which the strain transducer element is attached; and

a protecting hood mounted on top of the base plate so that it encloses the strain transducer unit.

20. A sensing element for measuring loads comprising:

a strain transducer unit including a strain transducer element;

a base plate on which the strain transducer unit is mounted and by which said strain transducer unit can be fixed on a measuring point of a structure such that the base plate does not move relative to the structure when a load is being measured, wherein the base plate lies substantially in a plane and is symmetrical about at least three axes extending within said plane and through a center of the base plate, and said base plate includes a middle region to which the strain transducer element is attached;

a protecting hood which includes a protecting material and which is mounted on an upper surface of the base plate for enclosing the strain transducer unit, and wherein an outer edge of the base plate extends beyond an outer periphery of the protecting hood; and

the base plate and the protecting hood each include a metal sheet.

21. A sensing element according to claim 20 wherein the base plate is a square plate.

22. A sensing element according to claim 20 wherein the base plate has an octagonal shape.

23. A sensing element according to claim 20 wherein the base plate is a round disk.

24. A sensing element according to claim 20 wherein the strain transducer unit comprises strain gauge elements arranged to form an isosceles triangle.

25. A sensing element according to claim 20 wherein the strain transducer unit further includes an A/D converter and a data processing unit, for converting an analog measuring message to digital form and for pretreating the measuring data.

26. A sensing element according to claim 20 wherein the strain transducer unit comprises:

strain gage elements arranged to form an isosceles triangle;

an A/D converter and a data processing unit for converting an analog measuring message to digital form and for pretreating measuring data; and

a circuit board on which the strain gage elements, the A/D converter and the data processing unit are attached.

27. A sensing element for measuring loads comprising:

a strain transducer unit including a strain transducer element and a circuit board on which a strain transducer element is tightly attached;

a base plate on which the strain transducer unit is mounted and by which said strain transducer unit can be fixed on a measuring point of a structure such that the base plate does not move relative to the structure when a load is being measured, wherein the base plate lies substantially in a plane and is symmetrical about at least three axes extending within said plane and through a center of the base plate, said base plate includes a middle region to which said strain transducer element is attached; and

a protecting hood which includes a protecting material and which is mounted on an upper surface of the base plate so that it encloses the strain transducer unit.

28. A sensing element according to claim 27 wherein an outer edge of the base plate extends beyond an outer periphery of the protecting hood.

29. A sensing element according to claim 28 wherein the circuit board is a round disc made of a thin plastic material;

and wherein the strain transducer element is attached in the middle of said circuit board and said circuit board is attached in a center of a middle region of the base plate.

30. A sensing element according to claim 28 wherein the strain transducer unit comprises strain gauge elements arranged to form an isosceles triangle.

31. A sensing element according to claim 28 wherein the strain transducer unit further includes an A/D converter and a data processing unit for converting an analog measuring message to digital form and for pretreating measuring data.

32. A sensing element according to claim 27 wherein the base plate is a square plate.

33. A sensing element according to claim 27 wherein said base plate has an octagonal shape.

34. A sensing element according to claim 27 wherein the base plate is a round disk.