| 摘要 |
A pull head (100, 100a) for installing pull type fasteners, such as rivetless nut plates. The pull head (100, 100a) includes a sleeve (102), a nosepiece (104) on the sleeve (102), and an insert (140, 140a) which extends from the nosepiece (104). The insert (140, 140a) enters an aperture (52) in a workpiece (54) and centers the pull head (100, 100a) relative to the aperture (52). The insert (140, 140a) is shiftable relative to the nosepiece (104), and preferably includes a taper (146, 146a) at its end (144) to facilitate entry into the aperture (52). The pull head (100, 100a) includes jaws (120) which grab and pull on a stem (58) or fastener, and the insert (140, 140a) provides that as the stem (58) or fastener is pulled, a surface of the stem (58) or fastener contacts the insert (140, 140a) and the insert (140, 140a) is pulled along with the stem (58) or fastener. As such, the insert (140, 140a) begins in the aperture (52), but is pulled out of the aperture (52) as the stem (58) or fastener is pulled to effect installation. |
