Pneumatic strength tester for sheet materials

Claim 1

A device for testing the strength of a moving sheet material, comprising: a gas reservoir having a throat therein; a valve disposed at the reservoir throat to regulate the flow of gas from the reservoir; a hollow member having a first hole at a first end thereof and a second hole at a second end thereof in flow communication with the first hole, the first hole being disposed adjacent to the valve to receive a flow of gas from the reservoir, the second end being adapted for slidable contact with one side of the moving sheet material; means for measuring gas pressure in the hollow member; and a sheet positioning guide having a hole therethrough, the sheet positioning guide being spaced from and disposed opposite the second end, so that the sheet material can move freely relative to the second end and the sheet positioning guide during testing.

Claim 2

A device for testing the strength of a moving sheet material, comprising: a gas reservoir having a throat therein; a valve disposed at the reservoir throat to regulate the flow of gas from the reservoir; a hollow member having a first hole at a first end thereof and a second hole at a second end thereof in flow communication with the first hole, the first hole being disposed adjacent to the valve to receive a flow of gas from the reservoir, the second end being adapted for slidable contact with one side of the moving sheet material; means for measuring gas pressure in the hollow member; and a sheet positioning guide having a hole therethrough, the sheet positioning guide being spaced from and disposed opposite the second end, so that the sheet material can move freely relative to the second end and the sheet positioning guide during testing.

Claim 8

A system for testing the strength of a sheet material, comprising: a chamber having one wall consisting of the sheet material to be strength tested; means for providing a rapid increase in gas pressure in the chamber; and means for measuring the pressure in the chamber.

Claim 9

A system for testing the strength of a sheet material, comprising: a chamber having one wall consisting of the sheet material to be strength tested; means for providing a rapid increase in gas pressure in the chamber; and means for measuring the pressure in the chamber.

Claim 13

A method for testing the strength of a sheet material, comprising the steps of: injecting a burst of high pressure gas into a chamber having one wall thereof formed of the sheet pressure material to be strength tested; and measuring the pressure of the chamber at the time that the sheet ruptures.

Claim 14

A method for testing the strength of a sheet material, comprising the steps of: injecting a burst of high pressure gas into a chamber having one wall thereof formed of the sheet pressure material to be strength tested; and measuring the pressure of the chamber at the time that the sheet ruptures.

Claim 18

A device for testing the strength of a sheet material, comprising: a gas reservoir having a hole therein; a valve disposed at the reservoir hole to regulate the flow of gas from the reservoir; a hollow member having a first hole at the first end thereof and a second hole in flow communication with the first hole, the first hole being disposed adjacent to the valve to receive a flow of gas from the reservoir; means for measuring pressure in the hollow member and producing analog signals indicative of the pressure in the hollow member; a sheet-positioning guide having a hole therethrough, the sheet positioning guide being spaced from and disposed opposite to the second hole; and means operatively coupled to the pressure measuring means for determining sheet strength based on the analog signal produced at the time the sheet ruptured, wherein the means for determining sheet strength includes a computer operatively coupled to the valve to regulate the flow of gas from the reservoir, an analog-to-digital converter operatively coupled to the pressure measuring means to digitize the analog signals of the pressure measuring means, a differentiating means operatively coupled to the analog-to-digital converter to compute a derivative of each digitized pressure measurement, a peak detecting means operatively coupled to the differentiating means to detect a peak derivative value computed by the differentiating means, and a computing means operatively coupled to the differentiating means for determining the pressure in the hollow member at the time at which the peak derivative value detected by the peak detecting means was obtained.

Claim 19

A device for testing the strength of a sheet material, comprising: a gas reservoir having a hole therein; a valve disposed at the reservoir hole to regulate the flow of gas from the reservoir; a hollow member having a first hole at the first end thereof and a second hole in flow communication with the first hole, the first hole being disposed adjacent to the valve to receive a flow of gas from the reservoir; means for measuring pressure in the hollow member and producing analog signals indicative of the pressure in the hollow member; a sheet-positioning guide having a hole therethrough, the sheet positioning guide being spaced from and disposed opposite to the second hole; and means operatively coupled to the pressure measuring means for determining sheet strength based on the analog signal produced at the time the sheet ruptured, wherein the means for determining sheet strength includes a computer operatively coupled to the valve to regulate the flow of gas from the reservoir, an analog-to-digital converter operatively coupled to the pressure measuring means to digitize the analog signals of the pressure measuring means, a differentiating means operatively coupled to the analog-to-digital converter to compute a derivative of each digitized pressure measurement, a peak detecting means operatively coupled to the differentiating means to detect a peak derivative value computed by the differentiating means, and a computing means operatively coupled to the differentiating means for determining the pressure in the hollow member at the time at which the peak derivative value detected by the peak detecting means was obtained.

Claim 20

A system for testing the strength of a sheet material, comprising: a chamber having one wall consisting of the sheet material to be strength tested; means for providing high pressure gas to the chamber, wherein the high pressure gas providing means includes a high pressure gas source, a reservoir which receives high pressure gas from the high pressure gas source, and a valve which regulates the flow of gas between the reservoir and the chamber; and means for measuring the pressure in the chamber.

Claim 21

A system for testing the strength of a sheet material, comprising: a chamber having one wall consisting of the sheet material to be strength tested; means for providing high pressure gas to the chamber, wherein the high pressure gas providing means includes a high pressure gas source, a reservoir which receives high pressure gas from the high pressure gas source, and a valve which regulates the flow of gas between the reservoir and the chamber; and means for measuring the pressure in the chamber.

Claim 22

A system for testing the strength of a sheet material, comprising: chamber having one wall consisting of the sheet material to be strength tested; means for providing high pressure gas to the chamber; and means for measuring the pressure in the chamber, wherein the pressure measuring means produces analog signals indicative of the pressure in the chamber, the device further comprising an analog-to-digital converter operatively coupled to the pressure measuring means to digitize the analog signals of the pressure measuring means, a differentiating means operatively coupled to the analog-to-digital converter to compute a derivative of each digitized pressure measurement, a peak detecting means operatively coupled to the differentiating means to determine a peak derivative value computed by the differentiating means, and a computing means to determine the pressure in the chamber at the time that the peak derivative value detected by the peak detecting means was obtained.

Claim 23

A system for testing the strength of a sheet material, comprising: chamber having one wall consisting of the sheet material to be strength tested; means for providing high pressure gas to the chamber; and means for measuring the pressure in the chamber, wherein the pressure measuring means produces analog signals indicative of the pressure in the chamber, the device further comprising an analog-to-digital converter operatively coupled to the pressure measuring means to digitize the analog signals of the pressure measuring means, a differentiating means operatively coupled to the analog-to-digital converter to compute a derivative of each digitized pressure measurement, a peak detecting means operatively coupled to the differentiating means to determine a peak derivative value computed by the differentiating means, and a computing means to determine the pressure in the chamber at the time that the peak derivative value detected by the peak detecting means was obtained.

Claim 24

A method for testing the strength of a sheet material, comprising the steps of: injecting high pressure gas into a chamber having one wall thereof formed of the sheet material to be strength tested; measuring the pressure in the chamber at the time that the sheet ruptures and producing analog signals indicative of the pressure therein; and inputting the analog signals to an analog-to-digital converter to produce digitized pressure measurements, inputting the digitized pressure measurements to a differentiating means to compute a first derivative of each digitized pressure measurement, inputting the first derivative of each digitized pressure measurement to a peak detecting means to detect a peak derivative value, and inputting the peak derivative value to a computing means to determine the pressure in the chamber at the time that the peak derivative value was obtained.

Claim 25

A method for testing the strength of a sheet material, comprising the steps of: injecting high pressure gas into a chamber having one wall thereof formed of the sheet material to be strength tested; measuring the pressure in the chamber at the time that the sheet ruptures and producing analog signals indicative of the pressure therein; and inputting the analog signals to an analog-to-digital converter to produce digitized pressure measurements, inputting the digitized pressure measurements to a differentiating means to compute a first derivative of each digitized pressure measurement, inputting the first derivative of each digitized pressure measurement to a peak detecting means to detect a peak derivative value, and inputting the peak derivative value to a computing means to determine the pressure in the chamber at the time that the peak derivative value was obtained.