Patent GB-428046-A (GB)
Title: Improvements in or relating to means for coupling road vehicles
IPC: B62D13/02
Filed: 1933-09-19
Abstract: 428,046. Tractor-trailer couplings. MACKAY, A. J., 2, Walfield Avenue, Whetstone, London. Sept. 19, 1933, No. 25877. [Class 79 (iii)] Relates to coupling devices for road trailers incorporating steering means which turn the front wheels of the trailer in the same direction as the coupling member for forward traction and in the reverse direction to that of the coupling member for backing movements, and comprises a trailer vehicle having a front steerable road wheel or wheels and non- steerable road wheels characterized by a steering member which is secured to the turntable framing carrying the steerable wheels for forward traction and is alternatively fulcrumed on the trailer main frame for reverse steering during backing movements. In the arrangement shown in Figs. 1 and 4, the coupling member h is horizontally hinged to the arms s<1> of a Y-shaped steering member S mounted on a pivot P<2> and connected to the trailer turntable t by a slot c<1> in the rear limb s<3> in which engages a block c on a pin P<1> fixed eccentrically in the turntable. The turntable t with the wheel frame f is rotatably mounted in the trailer frame F by lugs b rabbeted over the edge of a circular opening in a plate p attached to the frame F. The pivot P<2> of the steering member S is carried by radial extensions p<5> of a pair of annular plates p<3>, p<6> which are secured together by vertical spacing members and rotatably surround the turntable t. For forward traction, the plates p<3>, p<6> are locked to the turntable so that this and the steering wheels w move unitarily with the steering member S. For reversing operations, the plates p<3>, p<6> are locked to the trailer frame F so that the steering member S, fulcrumed on the pivot P<2>, turns the turntable through the pin-andslot connection P<1>, c<1>, in the opposite direction to that taken by the coupling member h. To connect the plates p<3>, p<6> alternatively to the trailer frame or the turntable, stop members r, r<9> are provided in a frame r<1> carried by the extensions p<5>, the stop member r comprising a slidable plate adapted to be moved radially inwards to engage a notch or recess p<2> in the edge of the turntable frame whilst the stop r<9> comprises a pivoted arm adapted to be moved outwards into engagement with a notch F<2> in apart F<1> of the trailer frame F. The operations are effected by a hand lever r<6> through a rod r<5> slidable in a bearing bracket r<20> in the frame r<1> and acting according to the tractive direction on the slide r<1> or the arm r<9> through springs r<11> as shown in Fig. 1. A catch r<15> holds the lever r<6> when depressed as shown with the stop r<9> in engagement with the notch F<2>. In the alternative actuation, the slide r may be secured in engagement with the recess p<2> by a screw-stop r<13>. The coupling member h is resiliently connected to the tractor T by a pivoted swivel-pin h<9> acting through springs h', h<8>. This arrangement enables the lever r<6> to be replaced, if desired, by a lever linkage connection to the pin h<9> controlling the engagement of the stops r, r<9> automatically according to the direction of tractive effort. A simpler form of the invention is shown in Fig. 9, wherein a drawbar h, having eccentric pin-andslot engagement P<1> with the turntable, moves longitudinally so that, for forward traction a pin P<2> thereon engages a notch f<5> in a frame f integral with the turntable t whilst, on backing movement, its rear end engages a recess F<5> in the trailer frame member F thereby reversing the steering effect. In another form, shown in Fig. 5, a toothed segment n to which the coupling member h is hinged, and which meshes with a segment m controlling the steering wheels, is fulcrumed to the main trailer frame by a pivot P<2> or alternatively fixed to the turntable f by pins A<1>, A<2>. Instead of toothed members, segments connected by chains or cables arranged on their peripheries may be employed. In a modification of the toothed form, Fig. 6 (not shown), locking detents or stops engaging notches in the edge of the segments are provided, the pins A<1>, A<2> being omitted. In a further arrangement, Fig. 7, the coupling member h is hinged to a plate n<3> having an internally toothed opening surrounding the turntable pivot b<2> and meshing with a set of planet pinions n<5> mounted on a secondary plate n<1>, the planet pinions also meshing with a central or sun gear wheel formed on the pivotal boss m<1> of the turntable, the boss being rotatably connected to the trailer frame F by lugs b<2>. For backing movements of the vehicles, the planet carrier plate n<1> is connected to the frame F by a pin A<1> introducing reversing gearing between the steering plate n<3> and the turntable frame f. For forward traction the pin A<1> is inserted in holes n<6>, n' connecting the plate n<3> directly to the turntable.