Patent GB-451103-A (GB)
Title: Improvement in the towing of road vehicles
IPC: B62D13/00
Filed: 1934-10-25
Abstract: 451,103. Steering vehicles. CUNNING- HAM, L. B. C., Southfields, Eastchurch, Sheppey, Kent. Oct. 25, 1934, Nos. 30599 and 31685. [Class 79 (v)] [See also Group XXXII] A towing connection between a trailer vehicle and an automobile vehicle, or forming part of an articulated vehicle is constructed to provide pivotal movement between the vehicles about an axis in front of the foremost axle of the trailer vehicle during forward travel, and about an axis behind the rearmost axle of the trailer vehicle when travelling in reverse, pivotal movement about the other of the two axes in either case being prevented. The arrangement provides a stable steering control over the trailer vehicle when travelling in reverse, whilst allowing a normal towing action during forward travel. As shown in Figs. 2 and 4, the connection comprises a bar 8 pivoted at 10 to a cross-bar 11 of the automobile, and at 7 to a frame member 6 of the trailer, the point 7 lying to the rear of the axle 4 of the road-wheels 2. Locking means for preventing movement of the bar 8 about the pivot 7 during forward travel comprise a transverse bar 13 secured to the frame of the trailer, and having downwardly directed ratchet teeth 15 and a central notch 16 for locking engagement with a spring-loaded bolt 12 carried by the bar 8. Locking means for preventing movement about the pivot 10 during rearward travel comprises a pair of side struts 32 pivoted at 33 to the automobile, and to sleeves 26 slidable on rods 23 each having ratchet teeth 25 and a central notch for locking engagement with spring-loaded pins provided in the sleeves 26. The rods 23 are rotably mounted in bearings on the bar 8, and can be turned so as to bring the ratchet teeth 25 and notches into and out of locking engagement with the sleeves 26, whereby pivotal movement about the point 10 is prevented or permitted. Both locking means are under the control of an operating handle 44 having a flexible connection 37 with arms 34 secured to the rods 23. As shown, the vehicle is set for forward travel, the sleeves 26 being free to slide on the bars 23, whilst the bar 8 is locked by engagement of the bolt 12 with the notch 16. On moving over the handle 44, the rods 23 are turned into locking engagement with the sleeves 26, and simultaneously the bolt 12 is depressed out of locking engagement with the notch 16 by means of a cam member 45 carried by a link 35 connecting the arms 34. The trailer is then free to turn about the point 7 on the bar 8 when turning during reverse travel. The ratchet teeth on the bars 25 and 13 are inwardly directed to aid in recentralizing the trailer after reversing on a turn. Steering motion may be imparted to the road wheels 2 during reverse travel by connections 49 and 50 with the bar 8, and a brake may be applied to the inside wheel by the movement of the bar 8 about its pivot 7 to aid the steering action. In the modification shown in Figs. 11 and 12, the connection comprises three bars 63, 64 pivoted centrally, and at either end, to the axle 65 of the trailer. The central bar 65 is pivoted permanently to the centre of a cross-bar 62 of the automobile, but the outer bars 63 have pivotal bearings at their forward ends adapted to slide in longitudinal slots in the cross-bar 62. For forward travel, the outer bars 63 are drawn together so that their pivotal connection with the automobile is central and coincident with that of the central bar 64. For rearward travel, the bars 63 are moved to the outer ends of the cross-bar 62, so that when turning, the trailer turns about an axis which is situated to the rear of the axle 65, as shown diagrammatically in Fig. 11. The bars 63 are urged together by a spring 72, and in order that they shall be moved automatically to the position appropriate to the direction of travel, are each connected by a cable 87 to a drum 89 surrounding the corresponding wheel drum 90. Pivoted to each wheel drum 90 are a series of pairs of oppositely directed driving pawls 92 engageable with a pivoted lever 95 on the drum 89, the lever 95 being held in alternative positions for driving engagement in opposite directions by a bifurcated stop 98 secured to a shaft 99. After a half revolution in either direction, an arm 100 on the shaft 99 engages one of two fixed stops on a fixed disc 104, which rotates the stop 90 and releases the connection between arm 95 and pawls 92. During fast forward travel, centrifugal weights 94 on the pawls 92 move them out of engagement with the operating lever 95.