Linkage assembly for in-line inspection tool

A method for inspecting a pipeline comprising:

• providing a sensor system including (A) a central body defining a central axis and (B) a plurality of sensor assemblies mounted to the central body and distributed circumferentially around the central axis, each sensor assembly of the plurality of sensor assemblies including (i) a sensor body having at least one sensor mounted thereto and (ii) first and second linkage assemblies mounted to the sensor body having the at least one sensor positioned between the first and second linkage assemblies, each linkage assembly of the first and second linkage assemblies including (a) a first link, (b) a second link, (c) a first pivot coupling the first link to the central body, (d) a second pivot coupling the second link to the first link, and (e) a third pivot coupling the second link to the sensor body, (f) a block positioned to prevent rotation about one of the first, second, and third pivots in response to urging of the sensor body away from the each linkage assembly;
• inserting the sensor system in the pipeline such that the sensor bodies of the plurality of sensor assemblies engage an inner wall of the pipeline;
• urging the sensor system through the pipeline in a first direction such that the inner wall urges the sensor bodies of the plurality of sensor assemblies toward the first linkage assemblies thereby causing the blocks of the first linkage assemblies to prevent rotation about the one of the first, second and third pivots of the first linkage assemblies;
• urging the sensor system through the pipeline in a second direction opposite to the first direction such that the inner wall urges the sensor bodies of the plurality of sensor assemblies away from the first linkage assemblies thereby causing the blocks of the first linkage assemblies to cease preventing rotation about the one of the first, second and third pivots of the first linkage assemblies.