Main chord member, standard knot and tower crane

The utility model relates to the field of wind power tower cranes, and discloses a main chord member, a standard knot and a tower crane, the main chord member comprises a member body (3) and a joint welded at the end part of the member body (3), a welding groove (4) is formed at the joint of the member body (3) and the joint, the welding groove (4) comprises an internal groove (6) at the bottom and an external groove (5) at the top, and the internal groove (6) is connected with the external groove (5). The width of the outer groove (5) is larger than that of the inner groove (6), a step is formed between the outer groove (5) and the inner groove (6), the welding groove (4) has enough space for a welding gun to conduct welding, a welding gun sleeve and the inner side of the connector cannot interfere, and welding integration is better. 本实用新型涉及风电塔式起重机领域，公开了一种主弦杆、标准节及塔机，其中，主弦杆包括杆体(3)和焊接连接于所述杆体(3)的端部的接头，所述杆体(3)与所述接头的连接处形成焊接坡口(4)，所述焊接坡口(4)包括底部的内部坡口(6)和顶部的外部坡口(5)，所述外部坡口(5)的宽度大于所述内部坡口(6)的宽度且二者之间形成台阶，所述焊接坡口(4)具有足够的空间