US 5,350,254 AGranted

Guided mole

AssigneeFoster-Miller, Inc.

InventorsAllan T. Fisk, David I. Freed, Thomas H. Mann

Life of this patent

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Abstract

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.

Claims19

Dependent claims

Moling apparatus for forming a generally horizontal underground passage in soil for a utility conduit or the like comprising

tool head structure that defines a tool axis, said tool head structure including a base portion and a nose portion mounted on said base portion,
said base portion being rotatable relative to said nose portion between a first position in which said nose portion has surfaces which are in symmetrical position with respect to said tool axis and a second position in which said nose surfaces are in asymmetrical position with respect to said tool axis so that said tool will tend to move through soil along a generally straight portion when said nose portion is in said first position and will tend to move through soil along a curved path when said nose portion is in said second position in response to propulsion forces applied to said tool head structure,
first surface structure for interacting with the soil in which said tool head structure is disposed to impart torque about said tool axis in a first rotational direction when said nose portion is in said first position and second surface structure for generating torque through interaction with the soil in the opposite rotational direction when said nose portion is in said second position.

Dependencies are inferred from the claim text.