GB745243A - Improvements relating to tractor-trailer hitches - Google Patents

Abstract

745,243. Vehicle couplings. MASSEYHARRIS-FERGUSON (SALES), Ltd., [formerly FERGUSON, Ltd., H.]. July 5, 1954 [July 3, 1953], No. 18428/53. Class 103 (5). A tractor of the type having power lift arms 1, Fig. 1, which can be used also to raise or lower a hitch arm 4, is provided with links 9 the lengths of which may be adjusted in a manner similar to a vernier gauge and are pivoted to extensions 10 of the arms 1, and pin and slot connected toggle links 14, 18, which may be actuated to maintain the hitch linkage rigidly propped in the raised position so that the power lift mechanism can be released. The tractor is also of the type having automatic means for putting the power lift out of action. The link 14 is U-shaped, Fig. 6, and is provided with a spring handle 19 co-operating with a locking plate 19D. In operation, when the arms 1 are raised the hitch 4 rises until a hump 4B thereon contacts a plate 4C which stops the rise just before the lift is automatically cut off. This stoppage occurs when the pins 18A of the toggle lost motion are midway along the slots 14A. Meantime the stem 19A of the handle has engaged the locking plate 19D to provide frictional resistance to ensure that the loose toggles do not move under gravity beyond their inactive aligned position in which the hitch 4 is supported by the linkage 1, 10, and 9. In order now to use the toggle links as a prop, the driver pulls the handle 19 towards the right in Fig. 1, and engages its stem 19A behind the plate 19D, thus moving the toggles over centre to take up the lost motion and permit the stop 20 to abut the casing 7. The power lift may then be released to allow the hitch linkage to drop and rest on the toggle, thus supporting the hitch 4 and the links 2 in a raised position. In order to release the hitch, the handle 19 is lifted and the arms 1 raised. The power lift is then operated to drop the arms 1 and the toggles are moved by the handle 19, and then folded by the dropping movement to the Fig. 1 position. In a modification the handle 19 may be dispensed with and the links allowed to fall into their propping position under gravity. A spring load may be applied to the toggles as an addition or alternative to the gravitational action.