Extensometer

• US 3,878,711 A
• Filed: 09/24/1973
• Issued: 04/22/1975
• Est. Priority Date: 09/24/1973
• Status: Expired due to Term

• Current Assignee: George J.J. Randolph Jr
• Original Assignee: George J.J. Randolph Jr
• Inventors: Randolph, George J. J. Jr.
• Primary Examiner(s): Gill, James J.
• Application Number:
  US05/400,186
• Time in Patent Office: 575 Days
• Field of Search: 73/88.5R,141A 33/147D,148D 338/5,6
• US Class Current: 33/788
• CPC Class Codes: G01L 5/0004 Force transducers adapted for mounting in a bore of the force receiving structure G01L5/0009 takes precedence

Abstract

An extensometer including an elongated bar whose medial portion is transversely slotted to accommodate, with longitudinal axial loading of the bar, relatively longitudinal movement between the end portions in the bar. An electromechanical deflection sensor is mounted in a recess provided in this medial portion to bend, or deflect, therein proportionally with such relative movement of the end portions.

Claims

1. An extensometer comprising an elongated bar including, intermediate its ends, a pair of longitudinally spaced, transversely overlapping slots which extend into the bar from opposite sides thereof, means located adjacent the ends of said bar accommodating attachment thereto at spaced-apart points to an external body, means in said bar between said slots defining an elongated recess having one end adjacent the base of one of the slots and its opposite end adjacent the base of the other slot, and an elongated electromechanical deflection-sensitive device mounted in said recess with one of its ends anchored therein adjacent one end of the recess and its other end anchored therein adjacent the other end of the recess.

2. In an extensometer, an elongated unitary body member comprising a pair of spaced-apart interface portions adapted for attachment to an external body and each characterized by a relatively high longitudinal spring rate, such being measured along a line paralleling the body member'"'"''"'"'s longitudinal axis, and a flexure portion joining said interface portions defined by at least a pair of transversely overlapping slots which are spaced along said axis and which extend inwardly from opposite sides of said member and including, between said slots, a recess for receiving a deflection-sensitive device, said flexure portion having a lower longitudinal spring rate, also measured parallel to said axis, than that of said interface portions, said flexure portion accommodating, with shear stressing therein, longitudinal relative movement between said interface portions with accompanying shear-bending in the flexure portion, and said recess accommodating coupling of an electromechanical deflection-sensitive device to said interface portions through a pair of spaced-apart points in the recess located adjacent the bases of said slots in such a manner that the device will be deflected by an amount proportional to the relative movement along the body member'"'"''"'"'s longitudinal axis which occurs between said interface portions.

3. An elongated extensometer comprising a pair of spaced-apart interface portions adapted for attachment to an external body, each characterized by a relatively high spring rate as measured along the extensometer'"'"''"'"'s longitudinal axis, a flexure portion integral with and disposed between said interface portions defined by at least a pair of transversely overlapping slots which are spaced along said axis and which extend inwardly from opposite sides of said body and including between said slots a recess for receiving a deflection-sensitive device, said flexure portion having a lower spring rate measured along said axis than that of said interface portions, said flexure portion accommodating, with shear-stressing therein, longitudinal relative movement between said interface portions with accompanying shear-bending in the flexure portion and an electromechanical deflection-sensitive device mounted in said recess in the flexure portion and coupled to said interface portions through spaced-apart points in said recess which are adjacent the bases of said slots so as to be proportionally deflected by such relative movement between said interface portions.