Patent GB-460769-A (GB)
Title: An improved trailer for road vehicles
IPC: B62D63/06
Filed: 1935-07-23
Abstract: 460,769. Steering vehicles. FAIRBROTHER, H. (Reversible Trailers, Ltd.) July 23, 1935, No. 20948. [A Specification was laid open to inspection under Sect. 91 of the Acts, Feb. 11, 1936.] [Class 79 (v)] [Also in Group XXXII] A trailer coupled to a towing vehicle is kept in track therewith during backing manoeuvres, by means of an horizontally swinging " direction " bar pivoted on the trailer and operated by a member on the towing vehicle in such manner that, when the vehicles move out of alignment, the direction bar is moved further out of alignment, this movement automatically steering the trailer wheel or wheels when the vehicles are being backed, but being dissociated therefrom during forward travel. In Figs. 7, 8, 9, 11 and 13, the invention is shown applied to the single-wheeled trailer described in Specification 460,768, the trailer wheel 12 thereof being, for this purpose, mounted in a frame 22 connected to the subframe 15 by a vertical pivot 24 with turntable bearing surfaces 25, 26. The sub-frame 15 is mounted between guides 18 and supported by a transverse leaf spring 16, its forward extension 50 being pivoted to a bracket 59, Fig. 13, on a main frame cross-bar 65. The direction bar 51 is pivoted at 55 on the extension 50 and is swung laterally when the vehicles move out of alignment by engagement of its forked forward end 56 with a pin 57 on a bar 58 carried by the coupling frame 3, 4 on the tractor vehicle. The control of the wheel for forward or backward travel is determined by means of a bar 45 with forked extensions 45<a> pivoted to the ends of horizontal extensions 46 of the wheel frame 22 and which is moved rearwardly, so that its upper end engages the frame 15 to fix the wheel frame for forward travel, or forwardly, so that its upper end engages a slot 54 in the rear end of the bar 51 for steering control when backing. To guide the bar 45 in its movements, the upper end of the frame 22 is provided with a slotted extension 61 in which the bar moves. The rear end of the controlling bar 51 lies over the extension 61 and terminates in inclined arms 53 connected by an arc-shaped bar 52 passing through a slot in a bracket 49 on the frame 15, the inclined arms 53 ensuring engagement of the bar 45 with the slot 54. To guide the bar 45 in its rearward movements, curved bars 68 connect the extension arms 50 to the brackets 49. The movements of the bar 45 are effected automatically according to the direction of travel by connecting it by rods 43, 44 to a pair of levers, pivoted at 42, one on each side of the frame 22, the levers terminating at their lower ends in toothed sectors 40, 41 co-operating with toothed wheels 33, 34 mounted on the ends of the wheel spindle and connected thereto through oppositely acting free-wheel clutches 35 so that one or other toothed gear is rotated according to the direction of travel. The sectors are so arranged that whilst the one meshing with the clutch driven gear-wheel is thrown out of mesh and held by a spring 47, as shown in Fig. 8, the sector on the opposite side of the frame remains in mesh with the gear on that side, which is idling, so that on the direction of travel being reversed it is in turn similarly thrown out of mesh. The rocking movements of the sectors thus move the bar 45 backwards or forwards according to the direction of travel. The wheel 12 is mounted in the frame 22 by means of a spindle 27 secured by a nut 37, the free-wheel centres being secured to end sleeves 28 rotating in ball bearings 29 and connected to the wheel hub 23 by dog-clutches 38. Figs. 16-18 show the application of the invention to a two-wheeled trailer, the wheels being mounted on pivoted stub axles connected in the usual manner by a track rod. In this arrangement, the pair of oppositely driven free-wheel pinions 33, 34 are mounted on the hub of one of the road wheels, Fig. 17, the toothed sectors 40, 41 meshing therewith being carried by a single lever 72 pivoted at 73 to an extension 75 of the stub axle, with a retaining spring 74 passing over the pivot centre to hold the lever in either of its extreme positions. The lever 72 is connected by a link 76 to one arm of a U-shaped rocking bar 77 pivoted in bearings 78 on the track rod 79, Fig. 16, the other arm thereof being connected by a link 84 to a locking arm 83 corresponding to the locking arm 45 in the previous form. The arm 83 is carried by an angle bracket 81 on the track rod, being guided in its movements. by a slot 82 therein. A frame 86, 87 mounted on the trailer axle carries the direction bar 51 (not shown) and associated guiding means, the locking arm 83 being moved laterally thereby when the vehicles are backing to operate the track rod and thus control the direction of the wheels.