TUBULAR TRANSDUCER WITH STRAIN GAUGES AND SENSITIVE TO A FORCE TRANSMITTED TO ITS END SURFACES VIA LOAD SURFACES

• US 3,736,795 A
• Filed: 05/20/1971
• Issued: 06/05/1973
• Est. Priority Date: 06/01/1970
• Status: Expired due to Term

• Current Assignee: John-Erik Andersson
• Original Assignee: John-Erik Andersson
• Inventors: Andersson, John-Erik
• Primary Examiner(s): Ruehl, Charles A.
• Application Number:
  US05/145,409
• Time in Patent Office: 747 Days
• Field of Search: 73/140,141A 338/2,5
• US Class Current: 73/862.632
• CPC Class Codes: B21B 2203/38 Strain gauges
• CPC Class Codes: B21B 38/08 for measuring roll-force
• CPC Class Codes: G01L 1/2231 the supports being disc- or ring-shaped, adapted for measuring a force along a single direction

Abstract

A tubular transducer for measuring compressive forces applied to the end thereof is provided with a plurality of axially and azimuthally displaced slots which make angles with the axis of the transducer to provide intermediate regions in the surface of the transducer that are joined by bridging regions which support strain gauges.

Claims

1. A transducer comprising a hollow tubular body which is symmetrical about its major axis, said body being provided with a plurality of slots extending completely through said body, said slots being intermittently located circumferentially about said hollow tubular body to define first and second members each having an end surface to which can be applied forces, the ends of adjacent slots being axially and circumferentially positioned with respect to each other to define at least three overlap parts which have a length dimension having a component which extends in the direction of said major axis, each of said overlap parts being provided with a cavity such that the overlap part operates as a beam and in cross-section resembles such beam having a web connecting two flanges, so that the cross-section has a relatively large moment of inertia, and strain gauges fixed to the portions of said overlap parts which constitute the web of the beam whereby when load forces are applied to said end surfaces maximum possible shearing stresses are applied to said strain gauges.

2. The transducer of claim 1 wherein the cross-section is an I-beam shaped with the direction of the web substantially parallel said major axis and the flanges are parallel to the portions of said slots adjacent thereto.

3. The transducer of claim 1 wherein said strain gauges are fixed to the portions of said overlap parts which constitute the web so as to be affected by deformations in two orthogonal directions which make 45* angles with the length axis of the associated overlap part.

4. The transducer of claim 3 further comprising a Wheatstone-bridge circuit including said strain gauges so arranged to give an indication only for components of the relative displacement of the end surfaces along said major axis.

5. The transducer of claim 1 wherein the direction of the portion defining the web is substantially parallel to said major axis.

6. the transducer of claim 1 wherein the direction of the portion defining the web is at an angle to said major axis.

7. The transducer of claim 1 wherein the length of each overlap part is less than three-Quarters of the length of a slot.

8. The transducer of claim 7 wherein the length of each overlap part is between one-quarter and one-half the length of a slot.

9. The transducer of claim 8 further comprising elements in the body adjacent the slots and extending into the slots to limit the mutual compressive travel of said first and second members to a value which is less than a possible maximum value.