門(men)(men)式(shi)起(qi)重(zhong)(zhong)(zhong)機(ji)(ji)(ji)(又稱(cheng)龍(long)門(men)(men)起(qi)重(zhong)(zhong)(zhong)機(ji)(ji)(ji))是橋(qiao)(qiao)架通過(guo)(guo)兩側(ce)支腿支撐在地(di)面軌道上(shang)(shang)的橋(qiao)(qiao)架型(xing)起(qi)重(zhong)(zhong)(zhong)機(ji)(ji)(ji)。在結構上(shang)(shang)由門(men)(men)架、大(da)(da)(da)車(che)運(yun)行(xing)機(ji)(ji)(ji)構、起(qi)重(zhong)(zhong)(zhong)小(xiao)車(che)和(he)電氣(qi)部(bu)(bu)分等組成(cheng)。有的門(men)(men)式(shi)起(qi)重(zhong)(zhong)(zhong)機(ji)(ji)(ji)只在一(yi)側(ce)有支腿，另一(yi)側(ce)支撐在廠房(fang)或(huo)棧橋(qiao)(qiao)上(shang)(shang)運(yun)行(xing)，稱(cheng)作半門(men)(men)式(shi)起(qi)重(zhong)(zhong)(zhong)機(ji)(ji)(ji)。門(men)(men)式(shi)起(qi)重(zhong)(zhong)(zhong)機(ji)(ji)(ji)的門(men)(men)架上(shang)(shang)部(bu)(bu)橋(qiao)(qiao)架(含主梁(liang)(liang)和(he)端梁(liang)(liang))、支腿、下橫(heng)梁(liang)(liang)等部(bu)(bu)分構成(cheng)。為(wei)了擴(kuo)大(da)(da)(da)起(qi)重(zhong)(zhong)(zhong)機(ji)(ji)(ji)作業范圍，主梁(liang)(liang)可(ke)以向一(yi)側(ce)或(huo)兩側(ce)伸出支腿以外，形成(cheng)懸(xuan)臂。也可(ke)采用(yong)帶臂架的起(qi)重(zhong)(zhong)(zhong)小(xiao)車(che)，通過(guo)(guo)臂架的俯仰(yang)和(he)旋轉擴(kuo)大(da)(da)(da)起(qi)重(zhong)(zhong)(zhong)機(ji)(ji)(ji)作業范圍。