Testing device for surfaces subject to impact

• US 5,490,411 A
• Filed: 06/27/1994
• Issued: 02/13/1996
• Est. Priority Date: 06/27/1994
• Status: Expired due to Fees

• Current Assignee: Paul Hogan
• Original Assignee: Paul Hogan
• Inventors: Hogan, Paul
• Primary Examiner(s): Raevis, R.
• Application Number:
  US08/266,944
• Time in Patent Office: 596 Days
• Field of Search: 73/12.01, 73/12.04, 73/12.06, 73/12.09, 73/12.11, 73/12.13, 73/12.14, 73/78, 73/79, 73/81, 73/82, 73/84, 73/658, 73/517 R
• US Class Current: 73/12.13
• CPC Class Codes: G01M 7/08 Shock-testing
• CPC Class Codes: G01N 2203/0033 Weight
• CPC Class Codes: G01N 2203/0617 Electrical or magnetic indicating, recording or sensing means
• CPC Class Codes: G01N 2203/0623 using piezoelectric gauges
• CPC Class Codes: G01N 2203/0676 Force, weight, load, energy, speed or acceleration
• CPC Class Codes: G01N 3/30 by applying a single impulsive force, e.g. by falling weight

Abstract

A testing device for surfaces subject to impact, comprising a transducer module and an electronics module cooperatively connected together. The transducer module includes an impact head for impact generally in the z-axis of a surface defined by an x and y-axis, and a transducer including an accelerometer aligned with the x, y and z axes for producing a voltage output proportional to the acceleration in each of the axes upon impact by the impact head on a surface. The electronics module includes a voltage source for supplying electrical energy and computer powered by the voltage source for vectorially adding the voltage output to determine the peak acceleration upon impact independent of the actual orientation of the impact head on the surface.

Claims

1. A testing device for surfaces subject to impact, comprising:

a transducer module and an electronics module cooperatively connected together;

said transducer module having an axially aligned handle and a shaped impact head for impact generally in the z-axis of a surface defined by an x and y-axis, said shaped impact head comprising an accelerometer means aligned with each of said axes for producing a voltage output proportional to acceleration in each of said axes upon impact by said impact head on said surface, said accelerometer means having an accelerometer for producing an analog signal proportional to force generated by said impact;

said electronic module having a means for supplying electrical energy to said electronic module, an amplifier, and an analog to digital converter for converting analog signals to conditioned digital signals and computing means for vectorially adding said conditioned signals to determine a peak acceleration of said impact head independent of orientation of impact of said impact head on said surface, said computing means comprising key-pad means for providing input into said computing means and display means for displaying output from said computing means, said computing means adapted to monitor said conditional signals and to collect data upon detection of an acceleration of said impact head above a predetermined value by taking a plurality of acceleration samples of said impact head per second for each axis and saving data for a predetermined period before said conditioned signals exceed a predetermined value to produce a data stream from said impact for use in calculating head injury criteria from said data stream, said computing means being programmed to save data from about one millisecond before said conditioned signals exceed said predetermined value to about 1 millisecond after said conditioned signals return to below said predetermined value to form a drop data collection, and calculating said head injury criteria from said drop data collection.

2. The device of claim 1 wherein said computing means monitors said conditioned signal by taking about ten thousand samples per second for each axis and saving data for said predetermined period before said conditioned signal exceeds said predetermined value thereby to form a drop data collection.

3. The device of claim 2 wherein said computing means scans said drop data collection in intervals of time to determine the time of the maximum acceleration.

4. The device of claim 3 wherein said computing means scans said drop data collection to determine said peak maximum acceleration.

5. The device of claim 1, wherein said modules are connected using an electronically conductive cord.

6. A testing device for surfaces subject to impact by a human head comprising a transducer module having an axially aligned handle and an impact head for impact upon a surface defined by an x and y-axis generally in a z-axis of said surface, said transducer module having an accelerometer for producing analog signals proportional to force generated by said impact, and an electronics module cooperatively connected to said transducer module for convening said analog signals to conditioned digital signals and it computing means for vectorially adding said conditioned signals to determine a peak acceleration of said impact head upon impact independent of direction of said impact by said impact head on said surface, wherein:

said computing means is adapted for monitoring said conditioned signals and for collecting data upon detection of an acceleration of said impact head above a predetermined value by collecting a plurality of acceleration samples per second of said impact head for each axis for a predetermined period of time before said conditioned signals exceed said predetermined value to a predetermined period of time after said predetermined value to produce a dam stream from said impact for use in calculating head injury criteria from said data stream, said computing means being programmed to save data from about one millisecond before said conditioned signals exceed a predetermined value to about one millisecond after said conditioned signals return to below said predetermined value thereby to form a drop data collection, and head injury criteria from said drop data collection.