Patent ID: 7509829

Claim:
A mandrel assembly receivable by an installation tool to operate on an opening in a workpiece, the assembly comprising: an inner elongated rod having an engagement section, a central section extending from the engagement section, an expansion section, and a tapered transition section between the expansion section and the central section, and a head section coupled to the expansion section with a shoulder formed therebetween, the tapered transition section shorter than the expansion section; and an outer member having a first end and a second end, the outer member slideably receivable by the expansion section of the inner elongated rod and axially movable along the inner elongated rod between a first position and a second position, the outer member biased towards the second position and configured to be in a first configuration for passing through the opening when in the first position and a second expanded configuration for expanding the opening when in the second position, the second end of the outer member engageable with the shoulder of the inner elongated rod to limit axial movement of the outer member relative to the inner elongated rod in a first direction.