Log-made truss structural material

A truss structural member for providing screw type joint devices on both ends of a log, which have a fastening bolt engaged with a screw hole of connector nodes, comprising:

• a log cut so as to form flat surfaces on butt ends thereof, a connector having a supporting hole which slidably holds the shank of said fastening bolt at the end of a node side thereof and a contacting surface which is seated on said butt end at the end of a counter-node side thereof, lag screws advanced against the log to fix said connector to the butt end of the log;
• said connector having a first element with said supporting hole, occupying one half of a node side thereof, and a second element with said contacting surface, occupying another half of the node side thereof, which engage with each other;
• said first element having an axial symmetrical part making a space to accommodate a part of said fastening bolt retractable through the supporting hole on the side of the counter-node thereof and a connecting threaded portion formed at the end of the counter-node side of said axial symmetrical part;
• said second element being a metallic seat provided with bores as large as the threaded portion of said lag screw passable therethrough, which has a threaded part engaged with said connecting threaded portion on the node side thereof and one or plural annular thorns driven into the butt end under a pressure load on the counter-node side thereof;
• and
• said screw type joint device having said fastening bolt and a sleeve for covering the fastening bolt, the bolt having a fastening threaded portion on the node side thereof and a stopper contacting an internal end surface of said first element on the counter-node side thereof and the sleeve has a sleeve hole for transmitting rotational torque to the fastening bolt and for sliding the bolt in an axial direction thereof.