Movax
From Wikipedia, the free encyclopedia
The movax has come to refer generally to any one of a number of specialized robotic excavator-mounted side-grip hydraulic vibratory pile drivers used to drive and extract sheet piling or other types of piles. The main advancement of the movax is in the handling and positioning of the pile. A combination of robotic articulation and side-gripping ability allows a single operator to drive and extract sheet piles, as well as to pick a sheet, move it, thread it, and place it.
A movax uses a high frequency hydraulic vibrator, typically mounted to a large excavator (or co-powered with a separate powerpack) and takes advantage of the excavator's own hydraulics for additional down force, up to 80 tons, depending on the equipment. With this power, a movax can be used to drive sheet piles, I-beams, and pipes in virtually any type of soil condition. The movax is limited by the fact that it is a vibratory pile driver, and so its ability to drive piles into dense soils is extremely limited. Although classed as a high frequency vibrator, it is neither "resonant free" or "variable moment" and so there is little control over the vibrations produced.
A movax is controlled by a cab-mounted computer which allows the operator to select a precise angle to drive/extract piles, even horizontally. A skilled operator can pick up, position and drive a pile in one fluid motion. With computer-assisted automatic steering and side grip ability, the movax/excavator combination automatically corrects the straightness of the sheet pile during the driving and extracting. When a movax drives the first pile into the ground, the distance is put into memory. The 'auto' takes the pile to the right distance near the guide and sets pile into the upright position, reducing the typical "walking" of the pile wall typical with other methods of installation. There are numerous claims as to the length of pile than can be driven. The true limiting factor is the pile mass, which should not exceed 830 kg.
The complexity of a movax is such that this product is better suited to the owner operator market rather than traditional non-operated plant hire. This view is supported by the fact that in the UK (as an example) no established piling equipment hirer supports movax; instead these units have proved more popular with specialist piling contractors. However, certain US-based equipment suppliers make movax available on short-term rentals.
There are several variants of the movax offered by various manufacturers under varying trade names.
