Method and apparatus for subsurface exploration

• US 6,488,105 B1
• Filed: 01/04/2000
• Issued: 12/03/2002
• Est. Priority Date: 01/04/1999
• Status: Expired due to Fees

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Wilcox, Brian
• Primary Examiner(s): Bagnell, David
• Assistant Examiner(s): Dougherty, Jennifer R
• Application Number:
  US09/477,499
• Time in Patent Office: 1,064 Days
• Field of Search: 175/19, 175/20, 175/21, 175/293, 175/298, 175/305, 405/159, 405/184
• US Class Current: 175/298
• CPC Class Codes: E21B 4/12 Electrically operated hammers
• CPC Class Codes: E21B 7/26 Drilling without earth removal, e.g. with self-propelled burrowing devices E21B7/30 takes precedence

Abstract

A subsurface explorer (SSX) for exploring beneath the terrestrial surface of planetary bodies such as the Earth, Mars, or comets. This exploration activity utilizes appropriate sensors and instrument to evaluate the composition, structure, mineralogy and possibly biology of the subsurface medium, as well as perhaps the ability to return samples of that medium back to the surface. The vehicle comprises an elongated skin or body having a front end and a rear end, with a nose piece at the front end for imparting force to composition material of the planetary body. Force is provided by a hammer mechanism to the back side of a nose piece from within the body of the vehicle. In the preferred embodiment, a motor spins an intermediate shaft having two non-uniform threads along with a hammer which engages these threads with two conical rollers. A brake assembly halts the rotation of the intermediate shaft, causing the conical roller to spin down the non-uniform thread to rapidly and efficiently convert the rotational kinetic energy of the hammer into translational energy.

Claims

1. A vehicle for exploring beneath the surface of a planetary terrain made of composition material, comprising:

a body having a front end and a rear end;

a nose piece fixed to the front end for imparting force to the terrain so that the vehicle penetrates the composition material in front of the nose piece and leaves the composition material deposited behind the rear end; and

a tether system for providing power and communication to the vehicle and returning subsurface samples, the tether system comprising;

two or more electrical conductors leading from a point of origin to the vehicle;

one or more capillary tubes for moving fluids from the point of origin to the vehicle; and

a spool for spooling the electrical conductors and the capillary tubes from within the vehicle and packing the electrical conductors and the capillary into the composition material deposited behind the rear end.

2. A hammer apparatus for imparting force to a nose piece for the purpose of fracturing composition material in front of the nose piece, comprising:

an intermediate shaft adapted for rotation relative to the nose piece;

a hammer portion adapted for rotation relative to the nose piece and of a shape receivable over the intermediate shaft in sliding engagement therewith;

a braking structure connected to the intermediate shaft; and

wherein the braking structure is configured to brake the rotation of the intermediate shaft and convert the rotation of the hammer portion into translational motion.

3. The hammer apparatus of claim 2, wherein the hammer portion is substantially annular in shape and is receivable over the intermediate shaft in sliding engagement therewith.

4. The hammer apparatus of claim 2, wherein the intermediate shaft has at least one outwardly directed thread of variable pitch extending some distance along the length of the intermediate shaft.

5. The hammer apparatus of claim 4, wherein:

the hammer portion further comprises at least one roller engaging the thread in a guiding relationship for guiding the hammer portion;

the intermediate shaft has a top end and a bottom end; and

the thread has a relatively low pitch at the top end of the intermediate shaft and a relatively high pitch at the bottom end of the intermediate shaft, whereby the hammer is accelerated downwardly when the rotation speed of the intermediate shaft is reduced.

6. The hammer apparatus of claim 5, wherein an electric motor is configured to rotate the intermediate shaft, and the hammer portion in an opposite direction of rotation to accelerate the hammer portion upwardly along the intermediate shaft, causing the roller to traverse the thread from the bottom end of the intermediate shaft to top end of the intermediate shaft.

7. The hammer apparatus of claim 2, wherein:

the hammer portion, intermediate shaft and braking structure are housed within a body having a front end and a rear end;

said nose piece is fixed to the front end of the body;

the hammer portion imparts a percussive force on said nose piece; and

said nose piece and body are configured such that the percussive force on the nose piece causes composition material in front of the nose piece to be deposited behind the rear end of the body.

8. The hammer apparatus of claim 7, wherein the body is elongated between the front end and the rear end.

9. The hammer apparatus of claim 8, wherein said nose piece and body are sealed against intrusion of composition material.

10. The hammer apparatus of claim 9, wherein the hammer portion, intermediate shaft and braking mechanism are spring mounted within the body.

11. The hammer apparatus of claim 9, wherein said nose piece and the body are configured such that the cross-sectional area of the nose piece exceeds that of the body, thereby reducing friction between the composition material and the side walls of the body during operation.

12. A system for converting rotational kinetic energy into translational kinetic energy comprising:

an intermediate shaft capable of rotation;

a thread of non-uniform pitch having a start point and an end point, the thread having a low pitch adjacent the start point and a high pitch adjacent the end point;

an annular hammer potion having a hollow center potion receiving the intermediate shaft; and

at least one conical roller for movement therealong carried by the hammer portion and engaging the thread such that when the intermediate shaft and hammer potion are rotated together and the rotation speed of the intermediate shaft is suddenly reduced the conical roller follows the thread thereby converting the kinetic energy of the hammer portion from rotational energy into translational energy as the conical roller moves from the low pitch portion of the thread to the high pitch portion of the thread.