GB1225481A - - Google Patents

Abstract

1,225,481. Self-steering axle assemblies. YORK TRAILER CO. Ltd. 14 March, 1968 [14 Dec., 1966], No. 55923/66. Heading B7H. A semi-trailer has a self-steering axle assembly comprising an axle 6 which is mounted for free movement longitudinally of itself and carries stub axles and kingpins 8 for road wheels 2, the stub axles being pivotally connected by an arm 18 at each side to a track rod 20 or its equivalent disposed parallel to and forwardly of the semitrailer, means 82 being provided to centralize and lock the track rod for forward movement of the semi-trailer and means also being provided to cause castor action on unlocking of the track rod 20 for reverse movement. In Fig. 4 the track rod 20 is locked by operating the linkage 82 by rotating a threaded rod 76 by a motor 74 until blocks 84 abut shoulders 90 on the track rod and the means to permit castor on reverse movement comprises a second track rod 16 and linkage 82 operated by the motor 74 one track rod being locked as the other is unlocked. In castoring operation the arms, 18, kingpins, 8, and wheels 2 pivot about the pivots 44 of the locked track rod while the axle slides in bearings 14 carried by a sprung mounting tube 10. In alternative arrangements two track rods are each provided with two sets of inwardly facing teeth 50, 52 selectively engageable by pairs of pawls (Fig. 2, not shown) or, Fig. 1, the track rod 16 is locked by rubber springs 28 forcing levers 36/40 into engagement with further arms 42 pivoted to the track rod and unlocked by inflating a bag 26 which both pivots the levers 36/40 away from the track rod 16 and extends track rod equivalent portions 20A, 20B into engagement with recesses 24 in the ends of the arms 18 for reverse movement. In a further two embodiments, a single lockable track rod is provided, castoring on reverse movement being provided by inclining the kingpin axis at an angle to give less castor effect than that produced by the arm and track rod (Fig. 5, not shown) or by mounting the kingpin in a rearwardly extended end of the axle (Fig. 6, not shown).