| 摘要 |
A device to retain screws during insertion into an object such as a bone by use of a screw-driver. The device comprises comprising a gripping sleeve the free end of which has a radially expandable portion for receiving the screw and the other end of which has at least one radial bore for movably receiving a locking ball. A safety sleeve is slidingly disposed on an outer surface of the gripping sleeve. The safety sleeve blocks an expansion of the expandable portion when in a position which is toward the free end with respect to the gripping sleeve and releases the expandable portion when in a position which is toward the free end with respect to the gripping sleeve. A handle is axially movable and hold the first locking ball in engagement with an annular groove of the gripping sleeve. A first spring acts between an inner shoulder at the end of the handle portion facing the expandable portion and a radial shoulder of the safety sleeve. An interlocking mechanism is provided acting between the safety sleeve and the gripping sleeve, which axially secures the safety sleeve in a blocking position relative to the gripping sleeve.
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