Resources Contact Us Home
Rotary earth boring tool

Image Number 4 for United States Patent #4406332.

The present invention provides a nonstalling system for advancing a boring tool in situations where the inclination of the bore hole with respect to the vertical is such that the force of gravity does not provide effective forward thrust. A hydraulically powered marine screw propeller adjacent the boring tool provides the necessary thrust for the drilling operation. Pressurized drilling fluid provides the required hydraulic energy. The characteristics of the marine screw propeller are such that it provides maximum thrust at maximum rotative speed but should the tool stall the forward thrust drops to zero preventing stalling.

  Recently Added Patents
Classifying documents using multiple classifiers
Identification of websites that break out of frames
Selecting content for storage in a multi-device cache
Specification of latency in programmable device configuration
Integrating multimedia capabilities with circuit-switched calls
Document layout method
Method and apparatus for receiving signals in a MIMO system with multiple channel encoders
  Randomly Featured Patents
Faucet spout
Hub for power transmission apparatus
Apparatus for opening a container and for dispensing a substance in a liquid beverage
Lighting installation
Composite water barrier sheet
Sampling-type optical voltage detector utilizing movement of interference fringe
Computer keyboard
Photosensitive composition for volume hologram recording
Amino compounds as processing stabilizers for thermoplastic materials
Driving circuit of a liquid crystal display and driving method thereof