GB1446065A - Device for connecting a semitrailer or an agricultural implement to an agricultural tractor - Google Patents

Abstract

1446065 Safety hitch LA MECANO-SOUDURE-REMOISE 10 Oct 1973 [11 Oct 1972 11 May 1973] 47404/73 Heading A1P Apparatus for hitching a tractor to an implement comprises a hook operated by the tractor lift mechanism, a spring biassed locking device for holding the hook in its upper position once engaged with the implement, a first safety device to prevent unlocking of the hook should the spring bias fail, and a second safety device to allow immediate uncoupling should the implement overturn. In one form, the hook comprises an implement engaging claw 6c and a projection 6d which, upon raising of the hook pivots cam shaft 17 against the bias of its end springs 24 until the cam 16 pivots into groove 6e. In this position the upper surfaces of transverse arms 13 are urged against cylinders of resilient material 45 which are housed in a plate 5 attached to the tractor and which constitute the first safety device. Should the springs 24 break the downward force exerted on the arms 13 by the resilient cylinders 45 maintains engagement of groove 6e and cam 16 and a projection 5b with pin 19. Should the implement overturn its coupling ring (not shown) engages arm 31 which pivots about shaft 34 to allow uncoupling. To uncouple, the hook is raised slightly by the tractor lift mechanism and the cam shaft is pivoted by actuation of a Bowden cable attached to a pin 18 Fig. 3. This then allows the hook to be lowered.