Multi axis force and moments transducer

• US 4,550,617 A
• Filed: 05/04/1984
• Issued: 11/05/1985
• Est. Priority Date: 05/06/1983
• Status: Expired due to Fees

• Current Assignee: Hispano Suiza SA (Safran SA)
• Original Assignee: Societe Nationale dEtude et de Construction de Moteurs dAviation SNECMA (Safran SA)
• Inventors: Fraignier, Bernard, Gery, Daniel E.
• Primary Examiner(s): Ruehl, Charles A.
• Application Number:
  US06/607,262
• Time in Patent Office: 550 Days
• Field of Search: 73/862.04, 73/862.05, 73/862.06
• US Class Current: 73/862.042
• CPC Class Codes: G01L 5/1627 of strain gauges using piezoresistors G01L5/162
• CPC Class Codes: G01L 5/226 to manipulators, e.g. the force due to gripping

Abstract

A multi-axis force and moment transducer having a plurality of flexible plates, orthogonally oriented, interconnected between first and second bodies to measure the forces exerted thereon due to relative movement between the bodies. The interconnection between a first element attached to the first body and a second element attached to the second body is affected by a plurality of first thin flexible plates and a plurality of second thin flexible plates, the ends of the plates being interconnected by a ball-joint coupling. The first thin flexible plates are oriented such that they flex in a direction generally perpendicular to a first axis, while the second thin flexible plates are oriented such that they flex in a direction generally parallel to such axis. Strain gauges may be provided on each of the thin flexible plates to provide an output of the forces.

Claims

1. A multi-axis force and moment transducer for determining the forces and moments existing between first and second bodies comprising:

(a) a first element attached to the first body, the first element having a first axis;

(b) a second element attached to the second body;

(c) a plurality of housing means disposed about the first element, each of the housing means defining a socket opening with a central axis extending generally perpendicular to the first axis;

(d) a plurality of first relatively thin flexible plates, each having a first end attached to the first element and oriented so as to flex only in a direction generally perpendicular to the first axis;

(e) first attachment means to attach a second end of each of the first flexible plates to a housing means, the first attachment means comprising a ball attached to the second ends of the first flexible plates such that the ball fits within the socket opening in the housing means;

(f) a plurality of second relatively thin flexible plates, each having a first end attached to the second element and oriented so as to flex only in a direction generally parallel to the first axis;

(g) second attachment means to attach a second end of each of the second flexible plates to a housing means; and

,

(h) means associated with each plate to determine the force exerted thereon by the flexing caused by relative movement between the two bodies.

2. The multi-axis force and moment transducer according to claim 1 further comprising anti-friction bearing means interposed between the ball and the socket opening.

3. The multi-axis force and moment transducer according to claim 2 further comprising second anti-friction bearing means interposed between the ball and the second ends of the first flexible plates.

4. The multi-axis force and moment transducer according to claim 1 wherein planes containing each of the second flexible plates are parallel to each other.

5. The multi-axis force and moment transducer according to claim 1 wherein the plurality of second flexible plates are located in a common plane.

6. The multi-axis force and moment transducer according to claim 1 wherein the number of first flexible plates is equal to the number of second flexible plates.

7. The multi-axis force and moment transducer according to claim 6 wherein the first flexible plates are 3 in number, extend in a radial direction from the first element and are equidistantly spaced apart.

8. The multi-axis force and moment transducer according to claim 7 wherein the first flexible plates all have the same length.

9. The multi-axis force and moment transducer according to claim 8 wherein central longitudinal axes of the first flexible plates lie in a common plane.

10. The multi-axis force and moment transducer according to claim 9 wherein the first element comprises a hub member and the second element comprises a ring member disposed about the hub member.

11. The multi-axis force and moment transducer according to claim 10 wherein the second flexible plates extend generally parallel to the ring member.

12. The multi-axis force and moment transducer according to claim 11 wherein the second flexible plates are of substantially equal length.

13. The multi-axis force and moment transducer according to claim 9 wherein the first element comprises a first shaft member and the second element comprises a second shaft member substantially coaxially aligned with the first shaft member.

14. The multi-axis force and moment transducer according to claim 13 wherein the second flexible plates extend substantially radially from the second shaft member.

15. The multi-axis force and moment transducer according to claim 14 wherein the second flexible plates are of substantially equal length.

16. The multi-axis force and moment transducer according to claim 15 wherein the housing means are attached together by a ring member which extends about the first and second shaft members.

17. The multi-axis force and moment transducer according to claim 9 wherein the first element comprises a first hub member and the second element comprises a second hub member substantially coaxially aligned with the first hub member.

18. The multi-axis force and moment transducer according to claim 17 wherein the second flexible plates extend substantially radially from the second hub member.

19. The multi-axis force and moment transducer according to claim 18 wherein the second flexible plates are of substantially equal length.

20. The multi-axis force and moment transducer according to claim 6 wherein the first flexible plates are there in number, two of the flexible plates disposed 180°

apart and a third flexible plate disposed 90°

from the two flexible plates.

21. The multi-axis force and moment transducer according to claim 1 wherein the means to determine the force exerted comprises a plurality of strain gauges attached to the sides of the first and second flexible plates.