line in fig1 and raised position which is denoted a in fig2 and creates a notably wide angle between boom and ground extend and retract of the boom itself 4 is provided by a hydraulic actuator 11 housed within stage 5 whose top end hinges with the top end of boom stage 6 via pin 12 and whose bottom end hinges likewise with the bottom end of stage 5 via pin 13 located at the top end of said boom assembly 4 at the top end of stage 6 thereof in fact one has a second boom assembly 16 which in the embodiment shown herein comprises two stages 17 and 18 see fig1 caused to slide coaxially one within the other the rear end of the outer of said stages stage 17 is fixed immovably to the top end of said boom stage 6 such that the longitudinal axes of respective boom assemblies 4 and 16 create an obtuse angle say of 110 u00b0 which will cause boom 16 to lie horizontal once stage 5 of the first boom assembly 4 is raised fully into position a see fig2 it will be observed that boom assembly 16 projects forward from stage 6 of the first boom along a path aligning with the longitudinal axis of prime mover 2 extend and retract of the second boom 16 thus described is brought about by further hydraulic actuator 25 this fixed at one end to stage 17 via lugs 22 and at the remaining forward end to stage 18.