Lag driver

Claim 1

A lag driver tool mountable in a drill chuck and screwgun to facilitate driving a lag screw having a flattened head member and an intermediate round shaft portion and a screw thread end portion, comprising: a driver means (11) having a shaft member (13), a body portion (15), and a pair of spaced apart arm members (17,18), said shaft member having one or more flat portions (21) to facilitate said shaft member being secured in the drill chuck, said body portion having a round exterior surface with a lower taper portion (16) extending into said shaft member to enhance junction strength between said shaft member and said body portion, said arm members each projecting from a ledge portion (34) a predetermined arm length and having a round exterior surface (23,24) and having an elongate semicircular shaped chamfer (19, 20) with a predetermined chamfer length (35) approximately equal to or less than the length (51) of the intermediate round shaft portion of the lag screw and having a lowe flat leg screw head engagement section (36,37) and being spaced apart a distance (47,55) to define a lag receiving slot 50 dimensioned for receiving a portion of the lag screw (28) with its flattened head member being juxtapositioned between said lag screw head engagement sections (36,37) and a portion of its shaft portion (29) being substantially laterally constrained between said chamfers (19,20); and a collar means (12) having a hollow elongate cylinder configuration with wall portions defining an inner diameter (41) and having a predetermined collar length (42), said inner diameter being approximately equal to or greater than the exterior diameter (60) of said body portion (15), said collar length being approximately equal to or greater than the length of said arm members, said collar means being force fitted about a portion of said arm members to constrain said arm members.