GB1355194A - Tractor and semi-trailer combinations - Google Patents

Abstract

1355194 Semi-trailer landing gear; fifth wheels KALMAR VERKSTADS AB 25 June 1971 [2 July 1970] 29810/71 Headings B7J and B7T In a tractor, semi-trailer combination, the semi-trailer [landing gear or] support leg structure 3 comprises two support legs 10 fixedly mounted on a shaft 11 pivotally mounted on the front of the semi-trailer and means, in the form of a pneumatic lifting cylinders 20 connected by levers 22 to the shaft, for rearwardly pivoting the legs from a ground engaging position, shown dotted in Fig. 1, to a rest position, shown solid in Fig. 1, when the semitrailer is respectively disconnected and connected to a pulling tractor; there being means, in the form of tension springs 18 connected to the shaft by levers 15, for pivoting the legs to their support position and means on the tractor, in the form of a vertically displaceable fifth wheel 1, for raising the front of the semi-trailer to allow movement of the legs between the said positions when relieved of the semi-trailer weight. To pivot the legs to their rest position the fifth wheel on the tractor is engaged on the semi-trailer and the latter raised thereby, the cylinders 20 are then energized with compressed air thus turning the shaft 11 as the piston rods are moved and the legs are pivoted, this action also tensions the springs 18. A locking device 30 to 33 installed to lock each leg in its ground engaging position and is unlockable by a respective piston and cylinder 34. The pneumatic circuit for controlling the cylinders 20 is connectible to a compressed air source on the tractor when the trailer is coupled thereto, and is described with reference to Fig. 4 (not shown).