US 5,123,284 AGranted

Method and apparatus for mesurement of tension in an elastic surface

OwnerJohn D. Edinburgh, Curtis D. Johnsoninventors

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Abstract

A method and apparatus are disclosed for the measurement of tension in a stretched elastic surface. The apparatus includes a rigid housing having at least two diametrically opposed sides and a spring device contained therein with a contact member connected to the spring device which protrudes a predetermined distance outwardly beyond the ends of the housing sides when the spring device is in a resting state. Measuring and display devices are connected to the spring device for measuring the spring deflection when the housing is pressed against an elastsic surface. The housing is placed adjacent the elastic surface to be measured with the contact member in contact with the elastsic surface such that a fixed distance exists between the ends of the housing sides and the surface prior to application of a pressing force. The housing is then pressed against the elastic surface until the ends of the housing sides come into contact with the surface such that the spring device is deflected. The deflection is measured and displayed as an indication of the tension in the elastic surface. In one embodiment the spring device is a cantilever beam with the measuring device being at least one strain gauge mounted thereon. In another embodiment, the spring device is a coil spring with the measuring device being a linear variable differential transformer.

Claims9

Dependent claims

An apparatus for measuring the tension in a elastic surface comprising;

a rigid housing having at least two diametrically opposed sides for contacting an elastic surface having a constant of proportionality dependent upon its surface material and the tension of which is to be measured,
spring means having a predetermined constant of proportionality secured within said housing and having a free end,
contact means connected to the free end of said spring means and protruding a predetermined distance outwardly beyond the ends of said housing sides for contacting the elastic surface to be measured when said spring means is in a resting state and deflecting said spring means upon sufficient force,
measuring means including display means operatively connected with said spring means for measuring the spring deflection when said housing is pressed against the elastic surface, such that
when said housing is placed adjacent an elastic surface to be measured with said contact means in contact with the surface a fixed distance will exist between the ends of the housing sides and the surface prior to application of a pressing force, and
upon pressing said housing against the elastic surface until the ends of said housing sides come into contact with the surface said contact means will cause deflection of said spring means which is measured by said measuring means and displayed as an indication of the tension in the elastic surface,
the tension of the elastic surface relative to deflection of said spring means being determined by the equation;
##EQU2## where T=tension of the elastic surface,
X=total deflection,
x=deflection of said spring means,
S=the spring constant, and
k=a constant number related to surface material.

9 more elements

A method of measuring the tension in a elastic surface comprising the steps of;

providing rigid housing having at least two diametrically opposed sides and spring means contained therein with contact means connected to said spring means and protruding a predetermined distance outwardly beyond the ends of said housing sides when said spring means is in a resting state and measuring means including display means operatively connected to said spring means for measuring the spring deflection when said housing is pressed against an elastic surface,
said spring means having a predetermined fixed constant of proportionality and said elastic surface having a constant of proportionality dependent upon the tension in its surface material,
placing said housing adjacent the elastic surface to be measured with said contact means in contact with the surface such that a fixed distance exists between the ends of the housing sides and the surface prior to application of a pressing force,
pressing said housing against the elastic surface until the ends of said housing sides come into contact with the surface such that said contact means will cause deflection of said spring means, and
measuring the deflection of said spring means and displaying the measurement as an indication of the tension in the elastic surface,
the tension of the elastic surface relative to deflection of said spring means being determined by the equation;
##EQU3## where T=tension of the elastic surface,
X=total deflection,
x=deflection of said spring means,
S=the spring constant, and
k=a constant number related to surface material.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/588,345Filed 26 Sep 1990
Granted: 23 Jun 1992
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G01L 5/106
Using electrical means: for measuring a reaction force applied on a cantilever beam
G01L 5/10
For measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands: using electrical means
G01L 5/108
Using electrical means: for measuring a reaction force applied on a single support, e.g. a glider
G01N 3/08
Investigating strength properties of solid materials by application of mechanical stress: by applying steady tensile or compressive forces