Patent ID: 7163112

Claim:
A material handling appliance, comprising an undercarriage ( 34 ), a slewing ring ( 36 ) mounted upon said undercarriage ( 34 ), a turntable ( 12 ) rotatably mounted upon said undercarriage ( 34 ) via said slewing ring ( 36 ) and comprising a first pivot point ( 22 ) to which a boom ( 14 ) is pivotally hinged, at least one lifting cylinder ( 24 ) arranged to pivot said boom ( 14 ) about said first pivot point ( 22 ), said turntable ( 12 ) being provided with a second pivot point ( 26 ) to which the lifting cylinder ( 24 ) is secured, a third pivot point ( 28 ) being situated where the at least one lifting cylinder ( 24 ) is secured to the boom ( 14 ), a fourth pivot point ( 32 ) being provided on said turntable ( 12 ) to rotate therewith and arranged such that the lower end of the boom ( 14 ) can be pivotally mounted therat instead of at said first pivot point ( 22 ), and a fifth pivot point ( 34 ) arranged such that the at least one lifting cylinder ( 24 ) can be secured thereto to pivot the boom ( 14 ) instead of being secured to said third pivot point ( 28 ), said first ( 22 ), second ( 26 ) and fourth ( 32 ) pivot points defining apices of a triangle having an obtuse angle located at the apex of said fourth pivot point ( 32 ), and said first ( 22 ) and fourth ( 32 ) pivot points being arranged with respect to one another such that pivoting said boom ( 14 ) at said fourth pivot point ( 32 ) from said first pivot point ( 22 ) results in shifting maximum moment of said lifting cylinder ( 24 ) from a steeper to a flatter setting angle with respect to ground.