Stripped hex head drive socket

Claim 1

In association with a gripper mechanism for the head of a bolt, wherein the bolt head has an end face, and a series of external flat side faces and interconnecting side corners, and said gripper mechanism comprises socket wall means that forms a socket sized to fit on the bolt head; said socket wall means comprising internal flat surfaces and interconnecting internal corners; said internal flat surfaces being equidistantly spaced from the socket axis, and said internal flat surfaces being sized to closely parallel the flat side faces on the bolt head to thereby exert turning forces thereon: the improvement comprising means forming at least two cutter ribs projecting inwardly from the socket wall means toward the socket axis; the spacing between the innermost edges of the cutter ribs and the socket axis being less than the corresponding spacing between the external surfaces of the bolt head and the bolt axis whereby when the gripper mechanism is positioned on the bolt head, the ribs will overlie the end face of the bolt head; said ribs being spaced and oriented so that a hammering force on the gripper mechanism causes the ribs to penetrate into the bolt head and form grooves therein; the inter-engagements between the ribs and groove surfaces being such that the gripper mechanism is enabled to exert a turning force on the bolt head even though the aforementioned corners had previously worn away; each cutter rib having an axial length that is almost as great as the axial dimension of the bolt head, whereby the ribs have extensive area contact with the head matter; said rib-forming means being comprised of an insert member formed separately from the socket wall means, said insert member being snugly fittable into the socket, said insert member being removable from the gripper mechanism, whereby the gripper mechanism can be utilized without the insert member; said insert member including an end plate and a plural member of rib walls extending at right angles to said plate, said plate having the same configuration as the outline configuration of the socket whereby when the insert member is inserted into the socket, the plate prevents said insert member from rotating in the gripper mechanism; said insert member having an axial length dimension slightly less than the corresponding dimension of the associated socket so that the ends of the cutter ribs are slightly recessed from an external end surface of the socket wall means, whereby the socket wall means can be centered on the bolt head prior to application of a hammering force on the gripper mechanism.