Flexible pipe crawling device having articulated two axis coupling

Apparatus for moving through a pipe having an axis and a wall, said pipe having bends wherein said axis curves, said apparatus comprising:

• a front leg assembly defining a first plane generally perpendicular to said axis, said front leg assembly having
• a first plurality of feet, and
• a first plurality of actuators, each actuator in operative connection with one foot of said first plurality of feet, said each actuator moving said foot radially with respect to said axis between an extended position and a retracted position;
• a rear leg assembly defining a second plane generally perpendicular to said axis, said front leg assembly separated from said rear leg assembly by a distance, said front and rear leg assemblies having a nominal alignment whereby said first and second planes are parallel, said rear leg assembly having
• a second plurality of feet, and
• a second plurality of actuators, each actuator in operative connection with one foot of said second plurality of feet, said each actuator moving said foot radially with respect to said axis between an extended position and a retracted position;
• and
• means for connecting said front and rear leg assemblies, said connecting means including
• first means for changing said distance between said front and rear leg assemblies, said front and said rear leg assemblies moving between a retracted position and an extended position as said first changing means changes said distance, said distance being greater when said front and said rear leg assemblies are in said extended position than when in said retracted position, said first changing means having a first end and a second end, said first end connected to said rear leg assembly, and
• a joint rotatable about at least two axes of rotation for changing said alignment of said front and rear leg assemblies with respect to each other, said alignment of said first and said second planes changing from said nominal alignment in response to lateral pressure on said apparatus by a bend in said pipe, said second means having a third end connected to said front leg assembly and a fourth end connected to said second end.

Apparatus for moving through a pipe having an axis and a wall, said pipe having bends wherein said axis curves, said apparatus comprising:

• a front leg assembly defining a first plane generally perpendicular to said axis, said front leg assembly having
• a first plurality of feet,
• a first plurality of actuators, each actuator in operative connection with one foot of said first plurality of feet, said each actuator moving said foot radially with respect to said axis between an extended position and a retracted position, and
• a first plurality of wheels, each of said first plurality of wheels radially adjacent to one foot of said first plurality of feet and having a axis of rotation perpendicular to the direction of movement of said apparatus;
• a rear leg assembly defining a second plane generally perpendicular to said axis, said front leg assembly separated from said rear leg assembly by a distance, said front and rear leg assemblies having a nominal alignment whereby said first and second planes are parallel, said rear leg assembly having
• a second plurality of feet,
• a second plurality of actuators, each actuator in operative connection with one foot of said second plurality of feet, said each actuator moving said foot radially with respect to said axis between an extended position and a retracted position, and
• a second plurality of wheels, each of said second plurality of wheels radially adjacent to one foot of said second plurality of feet and having a axis of rotation perpendicular to the direction of movement of said apparatus;
• means for connecting said front and rear leg assemblies, said connecting means including
• first means changing said distance between said front and rear leg assemblies, said front and said rear leg assemblies moving between a retracted position and an extended position as said first changing means changes said distance, said distance being greater when said front and said rear leg assemblies are in said extended position than when in said retracted position, said first changing means having a first end and a second end, said first end connected to said rear leg assembly, and
• a joint for changing said alignment of said front and rear leg assemblies with respect to each other and for enabling said apparatus to respond to changes in said alignment of said front and rear leg assemblies, said alignment of said first and said second planes changing from said nominal alignment in response to lateral pressure on said apparatus by a bend in said pipe, said joint having a third end connected to said front leg assembly and an a fourth end connected to said second end;
• and
• means for urging said front and rear leg assemblies toward said nominal alignment, said urging means having a fifth end connected to said front leg assembly and a sixth end connected to said second end.