GRAPHICAL DATA DEVICE

• US 3,821,469 A
• Filed: 05/15/1972
• Issued: 06/28/1974
• Est. Priority Date: 05/15/1972
• Status: Expired due to Term

• Current Assignee: Davis R, Fine S, Whetstone A
• Original Assignee: Davis R, Fine S, Whetstone A
• Inventors: WHETSTONE A, FINE S, DAVIS R
• Application Number:
  US05/253,417
• Time in Patent Office: 774 Days
• US Class Current: 178/18.04
• CPC Class Codes: G01S 5/30 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G06F 3/043 using propagating acoustic waves
• CPC Class Codes: Y10S 367/906 Airborne shock-wave detection
• CPC Class Codes: Y10S 367/907 Coordinate determination

Abstract

A graphical data device employing a stylus moving through a cubic space to be digitized and utilizing a fast rise time sound energy shock wave, generated by a spark at the location of the stylus and propagated through the air for providing three dimensional coordinate information as to the instantaneous position of the spark. Receiver devices are positioned along X, Y and Z coordinates and respond to the leading edge of the air propagated shock wave front to provide an elapsed time indication from the moment of spark generation to the moment of shock wave reception.

Claims

1. A system for generating data signals representative of the coordinates of points within a defined space, comprising:

a source of atmospherically transmissable signals, said source being movable about and throughout said defined space;

first, second and third elongated sound receptors oriented in mutually orthogonal relationship along three coordinate axes which define said space, each of said receptors having a cylindrical surface portion comprising a foil electret facing said defined space which senses the wave front of impinging signals transmitted by said source;

first, second and third time measuring means respectively coupled to said first second and third receptors, each of said time measuring means being further coupled to said source and operative to measure the time duration between a transmission by said source and the sensing of a wave front at its associated receptor; and

means responsive to the time durations measured by said time measuring means for generating data signals as a function of said time durations.

2. The combination of claim 1 wherein each of said sound receptors includes a plurality of sections, each section having an amplifier coupled thereto.

3. The combination of claim 1 wherein said amplifiers are physically mounted to their respective sections at the exterior of the receptors and outside the defined space.