Mitigation of booster-induced effects

Abstract

An improved articulated heavy haul trailer combination comprises a trailing accessory vehicle such as a booster coupled to a main trailer by a coupling. The coupling includes a horizontal hinge, a vertical hinge that allows the trailing accessory vehicle to yaw in a horizontal plane, a spreader extending between the hinges and a hydraulic piston and cylinder. A turn sensor mounted on said combination detects yawing, and a controller reduces the piston and cylinder's downward biasing force on the coupling.

Claims

1. An articulated heavy haul trailer combination comprising: a trailing accessory vehicle coupled to a main trailer by a coupling, said coupling comprising a horizontal hinge attaching said trailing accessory vehicle to said main trailer and allowing said coupling and said trailing accessory vehicle to pitch in a vertical plane, a vertical hinge allowing said trailing accessory vehicle to yaw in a horizontal plane and a connector extending between said horizontal hinge and said vertical hinge; at least one hydraulic piston and cylinder connected between said main trailer and said coupling for selectively providing a biasing force on said coupling in a vertical plane; characterized in that: said combination further comprises a turn sensor mounted on said combination for detecting that said trailing accessory vehicle is yawing in said horizontal plane in relation to said main trailer; and, a controller for receiving input from said sensor and, responsive to said input indicating that said trailing accessory vehicle is yawing in relation to said main trailer, controlling said hydraulic piston and cylinder to reduce the downward biasing force on said coupling or to increase an upward biasing force on said coupling.

2. An articulated heavy haul trailer combination comprising: a main trailer and a load-sharing accessory vehicle coupled to said main trailer and adapted to yaw in relation to said main trailer about a vertical axis and to pitch in relation to said main trailer about a horizontal axis; at least one hydraulic piston and cylinder connected between said main trailer and said accessory vehicle for selectively providing a biasing force on said accessory vehicle about said horizontal axis; characterized in that: said combination further comprises a turn sensor mounted on said combination for detecting that said accessory vehicle is yawing about said vertical axis; and, a controller for receiving input from said sensor and, responsive to said input indicating that said accessory vehicle is yawing in relation to said main trailer, controlling said hydraulic piston and cylinder to reduce a load component of said accessory vehicle in relation to said main trailer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) At least one mode for carrying out the invention in terms of one or more examples will be described by reference to the drawings thereof in which:

(2) FIG. 1 is a side elevation of a prior art heavy haul trailer and booster combination;

(3) FIG. 2 is a top oblique view showing the articulation of a prior art booster in the horizontal plane (yaw);

(4) FIG. 2(a) is a top side view showing the articulation of a prior art booster in the horizontal plane (yaw);

(5) FIG. 3 is a view taken from the rear and side of a prior art booster to illustrate the rolling force induced by a booster during a turn;

(6) FIG. 4 is a side elevation of a trailer and booster according to the preferred embodiment of the invention, riding straight, the connection between them being adapted for articulation in the vertical and horizontal planes;

(7) FIG. 5 is a side elevation of a trailer and booster according to the preferred embodiment, in a turn, and showing the hydraulic cylinder retracted to mitigate the booster yaw-induced effects on the trailer;

(8) FIG. 6 is a perspective view of the spreader and booster in a turn; and

(9) FIG. 7 is an enlarged view of circle A in FIG. 6.

DETAILED DESCRIPTION OF AT LEAST ONE MODE FOR CARRYING OUT THE INVENTION IN TERMS OF EXAMPLE(S)

(10) FIGS. 1, 2, 2A and 3 illustrate a prior art trailer 10 and booster 12 combination in which the hitch between them is adapted to allow the booster to yaw in relation to the trailer about vertical pins 14. The hitch comprises a spreader 16 that is adapted to pitch in the vertical plane about a horizontal pin 18. Hydraulic cylinders 20 may be used to bias the spreader 16, and hence the booster 12 itself, down or up about the horizontal pin 18 so as to increase or decrease the load-sharing of the booster.

(11) Referring to FIG. 3, when a turn is engaged and the main trailer is moving forward, the angular force induced by the yawing trailing accessory vehicle (i.e. the booster in the illustrated embodiment) manifests itself as a turning force as indicated by arrow 24. The present invention seeks to avoid or minimizing such turning force.

(12) A main trailer 30 and booster 32 combination according to the preferred embodiment of the invention is illustrated in FIGS. 4 and 7.

(13) The booster 32 can yaw in the horizontal plane by rotating about vertical hinge or pin 34 (shown in FIG. 5). A connector (i.e. a spreader 36 in the illustrated embodiment) extends between the vertical pin 34 and a horizontal hinge 37 (best seen in FIG. 4) about which the booster can pitch or pivot in the vertical plane (as shown by arrow 38). A pair of hydraulic cylinders 40 extend downward at an angle from the trailer 30 to the spreader 36. According to the preferred embodiment, in normal operation when the main trailer is travelling straight, the hydraulic cylinders 40 apply downward pressure to the spreader 36 (and therefore to the booster 32) to transfer some of the load from the main trailer 30 to the booster 32.

(14) A turn sensor 41 is mounted at the vertical pin 34 to detect the yaw of the accessory vehicle in relation to the main trailer, signifying that the unit is in a turn.

(15) As shown in FIG. 5, when a yaw condition is detected and exceeds a determined threshold turn angle, the downward pressure exerted on the booster by the hydraulic cylinders is reduced, thereby allowing some of the load from the booster to be transferred to the main trailer. As a result, the force tending to disrupt the main trailer's tracking of the turn and the tendency to roll that are induced by the booster are reduced.

(16) The output of sensor 41 is fed to a controller that controls the pressure exerted on the spreader 36 (and indirectly on the booster 32) by the hydraulic cylinders 40. The predetermined threshold turn angle is provided to avoid actuating the cylinders 40 in response to negligible turn angles. Beyond the threshold, the controller acts to relieve the pressure exerted by the cylinders on the booster as a function of the turn angle and the speed of the trailer.

(17) In the foregoing description, exemplary modes for carrying out the invention in terms of examples have been described. However, the scope of the claims should not be limited by those examples, but should be given the broadest interpretation consistent with the description as a whole. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.