Mine rescue system

• US 3,900,878 A
• Filed: 02/14/1973
• Issued: 08/19/1975
• Est. Priority Date: 02/14/1973
• Status: Expired due to Term

• Current Assignee: Carson K.H. Tsao
• Original Assignee: Carson K.H. Tsao
• Inventors: Tsao, Carson K. H.
• Primary Examiner(s): Curtis, Marshall M.
• Application Number:
  US05/332,532
• Time in Patent Office: 916 Days
• Field of Search: 343/112R,113R,225-228 325/28,67 340/26,18FM
• US Class Current: 340/854.5
• CPC Class Codes: G01S 1/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01V 15/00 Tags attached to, or associated with, an object, in order to enable detection of the object record carriers for use with machines having a detectable tag or marker G06K19/00
• CPC Class Codes: G01V 3/30 operating with electromagnetic waves
• CPC Class Codes: H04B 1/034 Portable transmitters

Abstract

A mine rescue system for locating trapped miners following a mine disaster. A transmitting device deployed by the trapped miners transmits a signal at a frequency below 3 kHz. The phase of the signal received on the surface is measured with respect to the signal received at an arbitrary reference point and the position on the surface is found where the phase lead is maximized over the reference thus locating the point below which the miners are trapped. The system may be extended to provide for two-way communications between the surface and the mine. Also, the invention encompasses means to guide a rescue drill bit.

Claims

1. In combination:

means for transmitting a signal through a region of earth, said signal having a frequency below 3 kHz, said transmitting means being located beneath the surface of the earth;

means for determining the position upon the surface of the earth below which lies said signal transmitting means comprising;

first and second means for receiving said signal upon the surface of the earth, said second receiving means being movable with respect to said second receiving means;

means for comparing the phase of said signal as received at said first receiving means with the phase of said signal as received at said second receiving means; and

means for determining the position upon the surface of the earth where the phase of said signal as received at said second receiving means is at a maximum lead over the phase of said signal as received at said first receiving means.

2. The combination of claim 1 wherein said transmitting means comprises:

means for producing an electrical signal; and

means for converting said electrical signal into a substantially magnetic signal through the earth.

3. The combination according to claim 2 wherein said converting means comprises a loop antenna.

4. The combination according to claim 3 wherein said loop antenna has a radius of two meters or less.

5. A system for locating the position on the surface of the earth directly below which lies a source of magnetic signals comprising in combination:

means for producing an electrical current, the frequency of said current being less than 3 kHz and said producing means being located below the surface of the earth;

a loop antenna coupled to said current producing means for transmitting said current as a magnetic signal, the plane of said antenna being substantially parallel to the surface of the earth;

first and second means for receiving said signal once transmitted, said first and second receiving means being located on the surface of the earth and each of said receiving means including a loop antenna substantially parallel to the surface of the earth, said first and second receiving means being movable with respect to one another; and

means for comparing the phase of said signal as received at said first receiving means with the phase of said signal as received at said second receiving means, said loop antenna coupled to said current producing means being directly below said loop antenna couplEd to said second receiving means when said phase at said second receiving means is at maximum lead over said phase at said first receiving means.

6. The combination according to claim 5 wherein said first receiving means is located at a stationary position while said second receiving means is capable of being transported.

7. The combination according to claim 6 further comprising means coupled to said first receiving means for coupling the signal as received by said first receiving means to said comparing means, said comparing means being located adjacent to said second receiving means.

8. A system for locating trapped miners by communication between the surface of the earth to a region in the interior of the earth where the miners are trapped wherein signals are transmitted and received in both locations comprising in combination:

means located below the surface of the earth for producing a first modulated signal, the phase of said first modulated signal being varied in accordance with a first preselected message, said first preselected message comprising a sequence of binary numbers;

first receiving means located adjacent to said means for producing said first modulated signals for receiving signals transmitted from the surface of the earth into said region, said first receiving means including means for producing an audible tone when signals transmitted from said surface are received at said first receiving means;

means coupled to said means for producing said first modulated signals and to said first receiving means for inhibiting said means for producing said first modulated signal when signals transmitted from said surface are received at said first receiving means;

first antenna means coupled to said means for producing said first modulated signals and to said first receiving means;

means located on said surface for producing a second modulated signal, said second modulated signal being switched on and off in accordance with a second preselected message, said second preselected message comprising a sequence of binary numbers;

second receiving means located adjacent to said means for producing said second modulated signal for receiving signals transmitted to said surface from said region, said second receiving means including means for determining which of said first preselected messages is being transmitted from said region;

means coupled to said means for producing said second modulated signal and to said second receiving means for inhibiting said means for producing said second modulated signal when signals transmitted from said mine are present; and

second antenna means coupled to said means for producing said second modulated signal and said second receiving means.