US 4,945,979 A · Robotic arm for delivering a tube plugging tool

Abstract

An improved robotic arm for effecting a tube plugging operation is disclosed herein. The improvement generally comprises the provision of a compliance coupling between the plugging tool and the guidance mechanism of the robotic arm that is compliant in three dimensions, thereby allowing the plugging tool to smoothly insert tube plugs into the mouths of heat exchanger tubes despite inaccuracies in alignment caused by sag and other factors. The improvement further comprises a length adjustment assembly for allowing the length of the base arm of the robotic arm to be easily and conveniently changed so that the robotic arm can service more than one particular type of nuclear steam generator, as well as an emergency release mechanism for remotely detaching the tool from the arm in the event of a jam. Finally, a rotary-type tube plug magazine is provided which includes a spring loaded drum having a plurality of spring clips mounted around its periphery for detachably retaining a large inventory of tube plugs and unloading these plugs without scratching. A stop mechanism with rollers prevents the tube plugs retained by the spring clips from rotating past an unloading position where the plugging tool can engage and smoothly remove the plug. Once a plug is removed at the unloading station, the torsional spring rotates the drum to advance another tube plug to the unloading position, where it may likewise be unloaded into the plugging tool.

Claims19

Dependent claims

An improved apparatus for delivering a tool designed for plugging a defective heat exchanger tube in a steam generator, said apparatus being of the type including a support member, a plug magazine mounted on the base arm for storing and unloading tube plugs, a guidance mechanism having said tool mounted thereon for aligning and positioning said tool relative to a selected tube to be plugged, a positioning mechanism movably supported on said base arm and having said guidance mechanism mounted thereon for positioning said tool between said selected tube and said plug magazine incident to a plug unloading operation,

wherein the improvement comprises a compliance coupling between said tool and said guidance mechanism that is compliant in three dimensions, including a first mounting member connected to said tool, a second mounting member connected to said guidance mechanism, and a plurality of extendible and compressible spring members connected between said first and second mounting members such that the compliance coupling exhibits both a high lateral flexibility and a high axial flexibility so that the plug may be axially aligned with the defective heat exchanger tube.

An improved apparatus for delivering a tool designed for plugging a defective heat exchanger tube in a steam generator, said apparatus being of the type including a support member, a base arm movably connected to the support member, a plug magazine mounted on the base arm for storing and unloading tube plugs, a guidance mechanism having said tool mounted thereon for aligning and positioning said tool relative to a selected tube to be plugged, a positioning mechanism movably supported on said base arm and having said guidance mechanism mounted thereon for positioning said tool between said selected tube and said plug magazine incident to a plug unloading operation,

wherein the improvement comprises means for adjusting the length of said base arm and a compliance coupling between said tool and said guidance mechanism that is compliant in three dimensions and includes a first mounting member connected to said tool, a second mounting member connected to said guidance mechanism, and a plurality of extendible and compressible spring members connected between said first and second mounting members such that the compliance coupling exhibits both a high lateral flexibility and a high axial flexibility so that the plug may be axially aligned with the defective heat exchanger tube.

An improved apparatus for delivering a tool designed for plugging a defective heat exchanger tube in a steam generator, said apparatus being of the type including a support member, a base arm movably connected to the support member, a plug magazine mounted on the base arm for storing and unloading tube plugs, a guidance mechanism having said tool mounted thereon for aligning and positioning said tool relative to a selected tube to be plugged, a positioning mechanism movably supported on said base arm and having said guidance mechanism mounted thereon for positioning said tool between said selected tube and said plug magazine incident to a plug unloading operation, wherein the improvement comprises:

a compliance coupling between said tool and said guidance mechanism that includes a first mounting member connected to said plugging tool, a second mounting member connected to said guidance mechanism, and a plurality of extendable and compressible spring members connected between said first and second members for rendering said coupling compliant in three dimensions, and
a rotary plug magazine including a bracket mounted onto said base arm, a drum means rotatably mounted on said bracket means having a plurality of clip means around its periphery for detachably retaining a plurality of tube plugs, a torsional spring means for urging said drum means to rotate about said bracket, a stop means for counteracting the torsional force applied to said drum means by said spring means, wherein said stop means stops a first tube plug retained by one of said clip means at an unloading position relative to said plugging tool, and wherein said torsional spring means advances a second tube plug to said unloading position after said first tube plug is detached from its respective clip by said plugging tool.

Dependencies are inferred from the claim text.

Robotic arm for delivering a tube plugging tool

Life of this patent

Robotic arm for delivering a tube plugging tool

Life of this patent

Abstract

Claims19