Scissor variable cross-section extending arm

The present invention discloses a variable section scissor extension arm. Cross-sectional shape of the extension arm existing space is constant, the spatial limits of the payload deployment supporting positioning. n drive slider according to the present invention constitutes an extension arm mount with sliding pair, and each driving block through a driving link articulated to the main; variable cross-section show off unit includes n scissor units, 2n slider and show a discount n corner blocks; pin of each corner block is fitted within the pin bore adjacent corners of the block, and two bottom arms are folded with a slide show composed of the sub-slider; n-scissor units forming the positive bevel shape, each top scissor unit with two flaps form a ball slide show sub; scissor units each variable cross-section a first stage unit off show two adjacent articulation drive shoe; variable cross-section off the remaining development units per scissor unit becomes a shear bar and the front two corners of the development unit sectional folding hinge corresponding connection block. Extension arm cross-sectional area of ​​the present invention decreases linearly unwinding direction, the root stress concentration can be effectively avoided.