Fork-lift attachment with four laterally displaceable prongs

Claim 1

A four-prong attachment for a fork-lift truck provided with a vertical lifting plate, comprising: a vertical support plate attached to said lifting plate forwardly of a front face thereof; two outer prongs and two inner prongs of generally L-shaped structure with upright legs lying in a plane forward of said support plate, the upright leg of each outer prong being provided with a pair of vertically separated horizontal mounting rails extending toward the other outer prong, said pairs of mounting rails being relatively offset in the vertical direction; two pairs of horizontal guide rails fixedly mounted in vertically spaced-apart positions on said support plate with profiles complementary to those of said mounting rails, each pair of mounting rails slidably engaging a respective pair of guide rails; two fluidic jacks respectively linked with said outer prongs and anchored to said support plate, said jacks being selectively operable to shift the respective outer prongs laterally in either direction with reference to said support plate, the upright leg of each inner prong being provided with holding means frictionally engaging the pair of mounting rails secured to the respectively adjoining outer prong for bidirectional entrainment by the latter upon a shifting thereof by the respective jack; and abutment means carried on said support plate for arresting said inner prongs in internal and external limiting positions while enabling further shifting of said outer prongs by said jacks.