Flexible pipe crawling device having articulated two axis coupling

• US 5,309,844 A
• Filed: 05/24/1993
• Issued: 05/10/1994
• Est. Priority Date: 05/24/1993
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Department Of Energy
• Original Assignee: United States Department of Energy (Government of the United States of America)
• Inventors: Zollinger, William T.
• Primary Examiner(s): Oberleitner, Robert J.
• Assistant Examiner(s): Morano, S. Joseph
• Application Number:
  US08/064,880
• Time in Patent Office: 351 Days
• Field of Search: 104/138.1, 104/138.2, 105/3, 105/176, 105/365, 213/75 R
• US Class Current: 104/138.2
• CPC Class Codes: F16L 55/30 of the propulsion means, e.g. towed by cables

Abstract

An apparatus for moving through the linear and non-linear segments of piping systems. The apparatus comprises a front leg assembly, a rear leg assembly, a mechanism for extension and retraction of the front and rear leg assembles with respect to each other, such as an air cylinder, and a pivoting joint. One end of the flexible joint attaches to the front leg assembly and the other end to the air cylinder, which is also connected to the rear leg assembly. The air cylinder allows the front and rear leg assemblies to progress through a pipe in "inchworm" fashion, while the joint provides the flexibility necessary for the pipe crawler to negotiate non-linear piping segments. The flexible connecting joint is coupled with a spring-force suspension system that urges alignment of the front and rear leg assemblies with respect to each other. The joint and suspension system cooperate to provide a firm yet flexible connection between the front and rear leg assemblies to allow the pivoting of one with respect to the other while moving around a non-linear pipe segment, but restoring proper alignment coming out of the pipe bend.

Claims

1. 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 connected to said front and rear leg assemblies for changing said distance and said alignment of said front and rear leg assemblies with respect to each other, said front and said rear leg assemblies moving between a retracted position and an extended position as said 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 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 changing means including a joint rotatable about at least two axes of rotation.

2. The apparatus as recited in claim 1, further comprising means connecting said front leg assembly and said changing means for urging said front and rear leg assemblies toward said nominal alignment.

3. The apparatus as recited in claim 1, further comprising a plurality of springs connecting said front leg assembly and said changing means for urging said front and rear leg assemblies toward said nominal alignment.

4. The apparatus as recited in claim 1, wherein said changing means is adapted to change said alignment of said front and rear leg assemblies about two axes of rotation, each of said two axes being generally perpendicular to said axis and to each other.

5. The apparatus as recited in claim 1, wherein said joint further comprises a gimbal for enabling said apparatus to respond to changes in said alignment of said front and rear leg assemblies.

6. The apparatus as recited in claim 1, wherein said joint is oriented so that each axis of rotation is generally perpendicular to said axis and to each other, said joint responding to changes in said alignment of said front and rear leg assemblies.

7. The apparatus as recited in claim 1, wherein said clamping means further comprises a joint for enabling said apparatus to respond to changes in said alignment of said front and rear leg assemblies, and said apparatus further comprising means connecting said front leg assembly and said changing means for urging said front and rear leg assemblies toward said nominal alignment.

8. The apparatus as recited in claim 1, wherein said changing means further comprises:

at least one air cylinder connected to said rear leg assembly; and

at least one ram, each ram slidably carried within each air cylinder of said at least one air cylinder and connected to said front leg assembly, said ram moving said front leg assembly in response to actuation of said air cylinder whereby said distance between said front and rear leg assemblies changes.

9. The apparatus as recited in claim 1, wherein said changing means further comprises:

a joint for enabling said apparatus to respond to changes in said alignment of said front and rear leg assemblies;

at least one air cylinder connected to said rear leg assembly; and

at least one ram, one ram carried within each cylinder of said at least one air cylinder and connected to said front leg assembly, said ram moving said front leg assembly in response to activation of said air cylinder whereby said distance between said front and rear leg assemblies changes.

10. 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.

11. The apparatus as recited in claim 10, further comprising 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.

12. The apparatus as recited in claim 10, further comprising a plurality of springs for urging said front and rear leg assemblies toward said nominal alignment, each of said plurality of springs having a fifth end connected to said front leg assembly and a sixth end connected to said second end.

13. The apparatus as recited in claim 10, wherein said joint further comprises a gimbal for enabling said apparatus to respond to changes in said alignment of said front and rear leg assemblies.

14. The apparatus as recited in claim 10, wherein said second changing means further comprises a joint for enabling said apparatus to respond to changes in said alignment of said front and rear leg assemblies, and said apparatus further comprises 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.

15. The apparatus as recited in claim 10, wherein said first changing means further comprises:

at least one air cylinder connected to said rear leg assembly; and

at least one ram, each ram slidably carried within each air cylinder of said at least one air cylinder and connected to said fourth end, said ram moving said front leg assembly in response to actuation of said air cylinder whereby said distance between said front and rear leg assemblies changes.

16. The apparatus as recited in claim 10, wherein said second changing means further comprises a joint for enabling said apparatus to respond to changes in said alignment of said front and rear leg assemblies, and wherein said first changing means further comprises:

at least one air cylinder connected to said rear leg assembly; and

at least one ram, each ram slidably carried within each air cylinder of said at lest one air cylinder and connected to said fourth end, said ram moving said front leg assembly in response to actuation of said air cylinder whereby said distance between said front and rear leg assemblies changes.

17. 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.

18. The apparatus as recited in claim 17, wherein said urging means further comprises a plurality of springs, each of said plurality of springs having a fifth end connected to said front leg assembly and a sixth end connected to said second end.

19. The apparatus as recited in claim 17, wherein said first changing means further comprises:

at least one air cylinder connected to said rear leg assembly; and

at least one ram, each ram slidably carried within each air cylinder of said at least one air cylinder and connected to said fourth end, said ram moving said front leg assembly in response to actuation of said air cylinder whereby said distance between said front and rear leg assemblies changes.

20. The apparatus as recited in claim 17, wherein said joint is rotatable about two axes of rotation, each axis of rotation being generally perpendicular to said axis and to each other, and wherein said urging means further comprises a plurality of springs.