Patent ID: 6550625
Filing Date: 2003-04-22
Classification: B66C,E02F

Abstract:
A boom arrangement for moving a work head comprising:a pillar supported for rotational movement around a vertical axis, a lifting boom pivotably connected to said pillar, a transfer boom having an end adapted for attachment to the work load, an intermediate lever pivotably connected to said lifting boom, a lifting cylinder having one end pivotably connected to said pillar and an opposite end pivotably connected to said intermediate lever, a tow bar pivotably connected to said intermediate lever, a transfer cylinder having one end pivotably connected to said lifting boom and an opposite end pivotably connected to the tow bar, an arm having one end pivotably connected to said transfer boom and an opposite end pivotably connected to said tow bar, an intermediate arm having one end pivotably connected to said lifting boom and an opposite end pivotably connected to said arm, said lifting cylinder being arranged below said lifting boom and acting as a pushing cylinder to produce folding of the lifting boom and the transfer boom to lift the work load, said transfer cylinder being operative to be lengthened and shortened while the lifting cylinder is inactive to displace the work head inwards towards the pillar and outwards away from the pillar, said transfer cylinder being connected to the tow bar by a pivot located below a line connecting pivots respectively connecting the tow bar to the intermediate lever and the tow bar to said arm so that when the transfer cylinder is lengthened and shortened, the work head travels inwards and outwards along a substantially horizontal line.