由于焊接技术的迅速发展,并且有了更精确的计算方法,现在起重机愈来愈多地采用实体的臂架来代替桁架,这样做,常常不考虑实际需要,而是从美观的观点出发。在技术上不很合理,如在中等的幅度时,在同样条件下,与桁架臂架比起来自重及造价都较高。特别是双拉杆变幅起重机,自重更大。从经济上 Due to the rapid development of welding technology and the more accurate calculation methods, cranes nowadays increasingly employ solid jibs instead of trusses. In doing so, they often do not consider the actual needs but rather from the aesthetic point of view. Technically not very reasonable, such as in the medium range, under the same conditions, compared with the truss boom weight and higher costs. In particular, double-rod luffing crane, heavier. Economically