Ladas & Parry
Expansion bolt unit for repeated use
 An expansion bolt unit includes a pull device which is fixed on an expansion tube embedded within a rigid material and has a portion which remains outside of the rigid material that is adapted to be activated by a puller to be removed from the rigid material. A bolt member extends through the expansion tube and is engaged threadably with a nut. The pull device includes one or more pull flanges extending radially and outwardly from the outer end portion of the expansion tube which remains outside of the rigid material. The bolt member has a hexagonal stub section at an outer end thereof so that a socket wrench can be engaged with the stub section. In one embodiment, a sleeving is sleeved on the bolt member between the expansion tube and the nut so that the nut can be rotated relative to the bolt member, thereby expanding the chuck jaw segments of the expansion tube by moving the bolt member relative to the expansion tube. 
F
F16B
inventional
Yuan-Ho
Lee