Fatigue enhancement of material surrounding openings in workpieces

A puller tool for cold working an opening in a split sleeve, the split sleeve having an elongated body, a radially extending flange attached to one end of the body, and a longitudinal gap down a length of the body for permitting the split sleeve to be biasly expanded and contracted;

• the puller tool comprising:
• an elongated mandrel having a first circumference portion sized to radially expand the split sleeve;
• a tool housing for receiving the mandrel and for axially guiding the mandrel;
• and
• a plurality of shafts assembled to have a cooperative interrelationship, the shafts comprising:
• a first shaft having a first set of fingers biasly cantilevered from a portion of the first shaft, the first set of fingers separated by a plurality of axial slots extending from the portion of the first shaft to a terminal end of the first shaft, each of the first set of fingers having a radially extending, tapered protuberance near the terminal end, the first shaft coupled to the tool housing and axially moveable with respect to the housing, the first shaft sized to receive the mandrel in a passageway formed within the first shaft;
• a second shaft having a second set of fingers biasly cantilevered from a first portion of the second shaft, the second set of fingers separated by a plurality of axial slots extending from the first portion of the second shaft to a terminal end of the second shaft, a second portion near the end of each finger being complementarily shaped to receive the protuberances on each of the first set of fingers of the first shaft without causing a radial expansion of the second set of fingers, a third portion of each of the finger shaped to engage the protuberances on each of the first set of fingers and cause the radial expansion of the second set of fingers, the second shaft affixed to the tool housing, the second shaft having a passageway sized to receive the first shaft;
• and
• a third shaft having a third set of fingers biasly cantilevered from a portion of the third shaft, the third set of fingers separated by a plurality of axial slots extending from the portion of the third shaft to a terminal end of the third shaft, each finger of the third shaft having a radially inwardly projecting flange, the third set of finger being in an expanded position when the protuberances on each the first set of fingers are recessed within the second portion of each of the second set of fingers, the third set of finger being in a relaxed position when the protuberances on each the first set of fingers are moved into contact with the third portion of each of the second set of fingers, the expanded position permitting the third set of fingers to receive the radially extending flange of the split sleeve, the contracted position permitting the radially inwardly projecting flanges on each of the third set of fingers to capture and at least temporarily retain the radially extending flange of the split sleeve, the third shaft having a passageway sized to receive the second shaft.

A cooperating shaft assembly for use with a puller tool to radially expand a split sleeve within an opening in a work piece, the assembly comprising:

• a first shaft having a passageway and radially inwardly projecting clamp jaws that are selectively deformable to form a radially expandable open end;
• a second shaft at least partially received by the first shaft, the second shaft having a first inner perimeter and a second inner perimeter, the first inner perimeter larger than the second inner perimeter, a detent region formed between an end of the second shaft and a transition region where the first inner perimeter transitions into the second inner perimeter;
• a third shaft having an outer perimeter and at least one tapered, radially extending protuberance located on the outer perimeter of the third shaft, the third shaft at least partially received by the second shaft and axially translatable with respect to the second shaft into a first position and a second position, the second position spaced from the first position,
• wherein in the first position the at least one protuberance engagably interacts with the second inner perimeter of the second shaft to permit radial expansion of the clamp jaws of the first shaft, and in the second position the at least one protuberance is located along the detent region of the second shaft to allow a radial contraction of the clamp jaws of the first shaft;
• and
• a mandrel axially coupled with the puller tool and axially moveable through the passageway of the first shaft, the mandrel having a cold working portion sized to radially expand the split sleeve.