05350254 is referenced by 8 patents and cites 29 patents.

Boring apparatus for forming a generally horizontal underground passage in soil for a utility conduit or the like that includes a tool head with a base portion and a nose portion mounted on the base portion. The base portion is rotatable relative to the nose portion between a first position in which nose portion surfaces are symmetrical with respect to the tool axis so that the tool will move along a straight path and a second position in which nose portion surfaces are in asymmetrical position with respect to the tool axis so that said tool will move along a curved path. By application of torque to the base portion, the base portion is shifted relative to the nose portion to shift the tool head from between an asymmetrical configuration and symmetrical configuration. Torque generating surface structure interacts with the soil and generates clockwise torque in one tool head position and counter clockwise torque in the other tool head position.

Title
Guided mole
Application Number
8/156060
Publication Number
5350254
Application Date
November 22, 1993
Publication Date
September 27, 1994
Inventor
Thomas H Mann
Littleton
MA, US
David I Freed
Weston
MA, US
Allan T Fisk
Needham
MA, US
Agent
Fish & Richardson
Assignee
Foster Miller
MA, US
IPC
F16L 1/00
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