초록 ▼

A pull gun (10) is used for pulling a mandrel (12, 150, 180) through an expandable sleeve (74, 144, 180) positioned in a fastener hole. The mandrel expands the sleeve as it moves therethrough causing the sleeve to put the metal which surrounds the hole in a state of compression. The pull gun has alt

A pull gun (10) is used for pulling a mandrel (12, 150, 180) through an expandable sleeve (74, 144, 180) positioned in a fastener hole. The mandrel expands the sleeve as it moves therethrough causing the sleeve to put the metal which surrounds the hole in a state of compression. The pull gun has alternative extensions or sleeve retainers having general appearances of collet chucks and they are adapted to be positioned adjacent holes being prestressed. The retainers are of relatively small diameter for operation through a drill fixture and in small spaces on a workpiece.

대표청구항 ▼

In a pull gun of a type which is used for pulling a mandrel axially through a one piece prestressing sleeve located within a fastener hole in a workpiece, said mandrel having an inner small diameter portion and outwardly thereof having an increasing diameter portion and an adjacent maximum diameter

In a pull gun of a type which is used for pulling a mandrel axially through a one piece prestressing sleeve located within a fastener hole in a workpiece, said mandrel having an inner small diameter portion and outwardly thereof having an increasing diameter portion and an adjacent maximum diameter portion, so that the increasing diameter portion and the adjacent maximum diameter portion of the mandrel can exert expansion forces on the sleeve, to cause the sleeve to be expanded in the radial direction and prestress the metal around the fastener hole, and in that manner improve fatigue properties of the metal, the improvement comprising: an axially split expandable sleeve retainer having a generally central passageway through which the mandrel travels axially and with which it is radially engaged as it is being retracted into the pull gun; an outer end of said retainer configured to axially engage said workpiece adjacent said fastener hole; said retainer having an inner end secured to said gun; and axially directed means associated with and in the other end of said retainer externally of said gun for axially retaining said sleeve in said fastener hole when said mandrel is moved axially through the fastener hole and through the sleeve.