TERMINAL TRACTOR DEVICE

Abstract: A terminal tractor equipped with a fifth wheel assembly (3) for carrying a load, said assembly being displaceable forward in order to make possible a stable handling of the load even in uphill driving.

Description: Terminal tractor device The present invention is an improvement of terminal tractors and similar vehicles, which by means of a so called fifth wheel support assembly can lift one end of and then tow trailers, that consequently only need wheels in their rear end. In order to achieve a suitable distribution of the loads on the front and rear axle of the tractor and to be able to turn with different types of trailers it is necessary to locate the fifth wheel in the vicinity of the rear axle of the tractor. In order to ensure clearance between the front end of the trailer and for example thresholds and height differences between ship and quay it is necessary that the fifth wheel can lift this end to an elevated position. When trailers are towed uphill the point of action of the load is shifted backwards, which involves a risk of overturning of the tractor. The purpose of the present invention is to obviate this risk of over- ' turning by means of a forwardly displacable fifth wheel, through which O PI /» WIP the point of action of the load in uphill driving can be moved so much forwards, that the stability of the tractor is ensured. In a preferred embodiment of the invention the displacement of the fifth wheel is brought about by means of hydraulic cylinders, but it can of course also be effected by means of screws, gears, chains or equivalent devices. The displacement can e.g. be controlled from the driver's cab or automatically by means of a device, which senses the load or the axle pressure. This device can also be arranged so, that it signals the driver or stops the tractor or in other ways prohibits further driving in an unstable condition, i.e. when the front axle pressure falls below a certain level, or when the front axle pressure is too high, i.e. when driving with a heavy load on level ground or downhill with the fifth wheel in its forward end position. One embodiment of the invention is illustrated by the accompanying drawings in which: Pig. 1 is a side view of a tractor, Fig. 2 is a side view of the fifth wheel assembly, Fig. 3 is a top view of the fifth wheel assembly, Fig. 4 shows schematically the lift arms in their lower and upper end positions. The tractor has front wheels 1 and rear wheels 2. Numeral 3 refers to the fifth wheel assembly, which carries the load, i.e. the trailer. The rear end position of the fifth wheel is shown in dash dotted lines, whereas the forward end position is shown in continuous lines. The lift arms 4 are pivoted at their left ends in the chassis and carry the fifth wheel 3 at their right ends, said ends also providing attachment for the hydraulic lift cylinders 5 that are attached to the chassis at their lower ends. Figures 2 and 3 show the fifth wheel 3 with its displacement cylinders 6. The whole unit 9 is disposed in the upper right part of the lift arms 4 and the fifth wheel 3 c n be moved between its forward and rear end position by regulation of the oil supply to the cylinders. Numeral 7 indicates the points to which the cylinders 6 are attached on the displacement unit 9 > which in turn is attached to . the lift arms 4 at points indicated by numeral 8. Figure 4 shows schematically the lift arms in their lower and upper end positions I and II respectively, and the displacement cylinders 6 in their inner end positions a and c respectively, and furthermore in their outer end positions b and d respectively. The support point of the fifth wheel ca n consequently be positioned arbitrarily within the area a, b, d, c, making possible a stable handling of the trailer at different loads and slopes. Instead of the shown lift arms and lift cylinders the fifth wheel can of course be carried by other kinds of mechanisms.

Claims: Claims : 1. A coupling assembly for connecting a trailer to a terminal truck or a similar vehicle equipped with a fifth wheel support assembly (3) or the like, said fifth wheel assembly being displaceable forwards and backwards on the vehicle, characterized in that the fifth wheel assembly (3) is displaceably and pivotally disposed on a lift- arm (4) » which is vertically, pivotally mounted on the chassis of the vehicle, the position of said fifth wheel assembly (3) being regulated in response to variations in the load on the front axle of the vehicle. 2. A coupling assembly according to claim 1, characterized by front axle load sensing means arranged to indicate the axle load for regulating the position of the fifth wheel assembly in response thereto. -3« A coupling assembly according to claim 2, characterized by an auto¬ matic control mechanism arranged to displace the fifth wheel assembly in response to the indicated axle load. 4. A coupling assembly according to any of the preceeding claims, characterized -in that a hydraulic lift device (5) is mounted between the chassis and the lift arm (4) for raising the lift arm. 5. A coupling assembly according to any of the preceeding claims, characterized in that a hydraulic displacement device (6) is mounted on the lift arm (4) for displacing the fifth wheel assembly (3)« ___O

Inventors: SANDQVIST A
Applicants: BYGG OCH TRANSPORTEKONOMIE AB, SANDQVIST A, BYGG OCH TRANSPORTEKONOMI AB
Application year: 1980
Main classification: B65G63
IPC codes: B62D49, B62D53