Finger walker for tube sheet

Claim 1

An apparatus for remotely traversing a flat surface having a regular array of identical openings on a uniform pitch, comprising: a rectangular base having four base fingers disposed in a rectangular pattern, the base fingers being adapted to selectively and in unison engage with and disengage from respective openings; base finger insertion means carried by the base for selectively moving said base fingers perpendicularly toward and away from the surface; an annular platform surrounding the base and connected thereto by bearing means for relative rotational motion between the base and platform in a plane substantially parallel to the surface; a plurality of platform fingers uniformly disposed about the platform, the platform fingers being adapted to selectively and in unison engage with and disengage from respective openings when said base fingers are engaged in respective openings; platform finger insertion means carried by the platform for selectively moving said platform fingers perpendicularly toward and away from the surface; drive means for rotating the platform relative to the base; means selectively advancing the platform relative to the base in increments of at least one pitch along the major axis of the base; control connection means for receiving remote control signals to advance the apparatus one cycle such that, (a) the platform fingers are inserted into and engaged with respective openings, (b) the base fingers are withdrawn from the surface, (c) the base is rotated within the platform until the major axis of the base is aligned with the intended direction of travel along the surface, (d) the base fingers are inserted into and engaged with respective openings, (e) the platform fingers are disengaged and withdrawn from the surface, (f) the platform is advanced a pitch multiple relative to the base along the axis direction; and (g) the platform fingers are inserted into and engaged with respective openings as in (a) above, whereby the entire apparatus has cycled.

Claim 2

An apparatus for remotely traversing a flat surface having a regular array of identical openings on a uniform pitch, comprising: a rectangular base having four base fingers disposed in a rectangular pattern, the base fingers being adapted to selectively and in unison engage with and disengage from respective openings; base finger insertion means carried by the base for selectively moving said base fingers perpendicularly toward and away from the surface; an annular platform surrounding the base and connected thereto by bearing means for relative rotational motion between the base and platform in a plane substantially parallel to the surface; a plurality of platform fingers uniformly disposed about the platform, the platform fingers being adapted to selectively and in unison engage with and disengage from respective openings when said base fingers are engaged in respective openings; platform finger insertion means carried by the platform for selectively moving said platform fingers perpendicularly toward and away from the surface; drive means for rotating the platform relative to the base; means selectively advancing the platform relative to the base in increments of at least one pitch along the major axis of the base; control connection means for receiving remote control signals to advance the apparatus one cycle such that, (a) the platform fingers are inserted into and engaged with respective openings, (b) the base fingers are withdrawn from the surface, (c) the base is rotated within the platform until the major axis of the base is aligned with the intended direction of travel along the surface, (d) the base fingers are inserted into and engaged with respective openings, (e) the platform fingers are disengaged and withdrawn from the surface, (f) the platform is advanced a pitch multiple relative to the base along the axis direction; and (g) the platform fingers are inserted into and engaged with respective openings as in (a) above, whereby the entire apparatus has cycled.