A bone plate system for internal fixation of bone fractures includes a bone plate having a plurality of bone plate holes. The holes are constructed to receive either a non-locking, locking, or variable-angle locking bone screw. The holes have discrete columns of teeth or thread segments arranged around the inner surface of the hole for engaging threads on the heads of locking and variable-angle locking bone screws. Conventional locking bone screws engage the bone plate coaxially with the central axis of the bone plate hole. Variable-angle locking bone screws can engage the bone plate at a selectable angle within a range of selectable angles relative to the central axis of the bone plate hole. The head of the variable-angle locking screw is at least partially spherical, and the thread thereon has a profile that follows the arc-shaped radius of curvature of the spherical portion of the screwhead.

In a die-casting machine with toggle-joint or without toggle-joint, a threaded section or a shaped section of horizontal columns is made by first carrying out turning and then rolling.

In a die-casting machine with toggle-joint or without toggle-joint, a threaded section or a shaped section of horizontal columns is made by first carrying out turning and then rolling.

There is provided an R- table apparatus which freely movies one table on a plane in the forward-and-rearward and leftward-and-rightward directions and in the rotational direction. The R- table apparatus changes a horizontal distance between a center line of a main axis of a driving apparatus and the action point by elevating an elevating base, and a table is moved to an arbitrary position without rotating along a guide member.

There is provided an R- table apparatus which freely movies one table on a plane in the forward-and-rearward and leftward-and-rightward directions and in the rotational direction. The R- table apparatus changes a horizontal distance between a center line of a main axis of a driving apparatus and the action point by elevating an elevating base, and a table is moved to an arbitrary position without rotating along a guide member.

A bone plate system for internal fixation of bone fractures includes a bone plate having a plurality of bone plate holes. The holes are constructed to receive either a non-locking, locking, or variable-angle locking bone screw. The holes have discrete columns of teeth or thread segments arranged around the inner surface of the hole for engaging threads on the heads of locking and variable-angle locking bone screws. Conventional locking bone screws engage the bone plate coaxially with the central axis of the bone plate hole. Variable-angle locking bone screws can engage the bone plate at a selectable angle within a range of selectable angles relative to the central axis of the bone plate hole. The head of the variable-angle locking screw is at least partially spherical, and the thread thereon has a profile that follows the arc-shaped radius of curvature of the spherical portion of the screwhead.

A bone plate system for internal fixation of bone fractures includes a bone plate having a plurality of bone plate holes. The holes are constructed to receive either a non-locking, locking, or variable-angle locking bone screw. The holes have discrete columns of teeth or thread segments arranged around the inner surface of the hole for engaging threads on the heads of locking and variable-angle locking bone screws. Conventional locking bone screws engage the bone plate coaxially with the central axis of the bone plate hole. Variable-angle locking bone screws can engage the bone plate at a selectable angle within a range of selectable angles relative to the central axis of the bone plate hole. The head of the variable-angle locking screw is at least partially spherical, and the thread thereon has a profile that follows the arc-shaped radius of curvature of the spherical portion of the screwhead.

The invention relates to methods of stabilizing bone implants, including inserting a self-tapping implant having at least two helical grooves running in opposite directions around the implant.

A threading tool includes: a tool main body; and a cutting edge portion, which is provided on a tip portion of the tool main body and has a rake face and a flank face. The cutting edge portion includes: a primary cutting edge extending in a tooth width direction of the cutting edge portion; two corner edges, one and other of which are provided on one and other of both ends of the primary cutting edge, respectively, and are in a convex curve shape; and two secondary cutting edges, one and other of which extend from the one and the other of the two corner edges to a rear end side of the cutting edge portion, respectively. Two secondary cutting edges are shorter than the primary cutting edge. At least one of the two secondary edges is slanted to a direction intersecting the primary cutting edge in an obtuse angle.

A threading tool includes: a tool main body; and a cutting edge portion, which is provided on a tip portion of the tool main body and has a rake face and a flank face. The cutting edge portion includes: a primary cutting edge extending in a tooth width direction of the cutting edge portion; two corner edges, one and other of which are provided on one and other of both ends of the primary cutting edge, respectively, and are in a convex curve shape; and two secondary cutting edges, one and other of which extend from the one and the other of the two corner edges to a rear end side of the cutting edge portion, respectively. Two secondary cutting edges are shorter than the primary cutting edge. At least one of the two secondary edges is slanted to a direction intersecting the primary cutting edge in an obtuse angle.