1 A VEHICLE TRAILER BIN AND LID Technical Field The present invention relates to transportable bins having a cover (lid) to close the open top of the bin during transportation, and more particularly but not exclusively to s road mobile bins that are tilted to empty the bins. Background of the Invention Road and rail bins used to transport bulk materials such as mined materials, are frequently tilted about a longitudinal axis to discharge the contents of the bin through a side door that is movable between a closed position and an open position. These bins io have an open top that is required to be covered. Frequently this will entail the use of tarps that are tied down. There are also roll tarp assemblies that are frequently motor driven. A still further means of covering the top of the bin is a lid that is pivotally mounted adjacent one longitudinal edge of the bin and via a hydraulic motor or other means the lid is movable between a closed position and an open position. is Tie down tarps have the disadvantage that they are very time consuming. Roll tarp assemblies are prone to damage and are unreliable. Pivot lid type assemblies suffer from the disadvantage that they project upwardly from the bin and therefore cannot be used in areas where there is limited "head room". For example, the lid when in the open position can prevent the bin being located under a hopper and may prevent the lid being 20 raised while in a work shed. Object of the Invention It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages. Summary of the Invention 25 There is disclosed herein a trailing including: a chassis; a bin mounted on the chassis and having a body with a pair of longitudinally extending side walls joined by a pair of transverse end walls, the walls providing a rim surrounding a top opening of the bin, the rim including first and second longitudinally 30 extending rim portions located on opposite sides of the opening and joined by transverse rim portions; a lid assembly including, 2 a lid having a longitudinal length and a transverse width and being configured to cover said opening, an arm having opposite first and second end portions, a first pivot, said first pivot pivotally attaching said first end portion to said lid to s provide for relative angular movement therebetween, a second pivot, said second pivot pivotally attaching said second end portion to said body to provide for relative angular movement therebetween, a link having opposite first and second end portions, a third pivot, said third pivot pivotally attaching the link first end portion to the 10 lid for relative angular movement therebetween, a fourth pivot, said fourth pivot pivotally attaching the link second end portion to said body to provide for relative angular movement therebetween, an hydraulic ram to move the lid between an open position covering said opening and a closed position located adjacent the first rim portion and remote from the second is rim portion, said ram having opposite first and second end portions; a fifth pivot, said fifth pivot pivotally attaching said ram first end portion to said arm intermediate the end portions of the arm, a sixth pivot, said sixth pivot pivotally attaching the ram second end portion to said body, and wherein 20 each pivot provides a pivot axis, with the axes being generally parallel and extending generally longitudinally of the body, and the second, fourth and sixth pivots are spaced transversely from each other relative to said body. Preferably, the arm, pivots, link and ram are located adjacent one of the end walls, and the lid assembly includes a further arm, the further arm having opposite first 25 and second end portions, a further first pivot, the further first pivot pivotally attaching the first end portion of the further arm to said lid to provide for relative angular movement therebetween, a further second pivot, the further second pivot pivotally attaching the second end portion of the further arm to said body to provide for relative angular movement therebetween, a further link having opposite first and second end portions, a 30 further third pivot, said further third pivot pivotally attaching the further link first end portion to the lid for relative angular movement therebetween, a further fourth pivot, said further fourth pivot pivotally attaching the further link second end portion to said body to provide for relative angular movement therebetween, a further hydraulic ram, the further ram having opposite first and second end portions, with the rams being operable to move 35 the lid between the open and closed positions of the lid, a further fifth pivot, said further 3 fifth pivot pivotally attaching the further ram first end portion to said further arm intermediate the end portions of the further arm, a further sixth pivot, the further sixth pivot pivotally attaching the further ram second end portion to the body, and wherein each further pivot provides a further pivot axis, with the further axes being generally parallel 5 and extending generally longitudinally of the body, and the further second, further fourth and further sixth pivots being spaced transversely from each other relative to said body, with the further arm, further pivots, further links and further arm being located adjacent the end wall other than said one end wall. Preferably, said lid is of a rectangular configuration so as to have a pair of io longitudinally extending side edges and a pair of transversely extending end edges joining the longitudinal edges, with said first pivot being attached to said lid adjacent one of said longitudinally extending edges, and said third pivot is spaced transversely from said first pivot. Preferably, said lid when in the open position is located adjacent one of the side is walls but spaced from said one of the side walls so that a longitudinal gap is provided between said bin and said lid. Preferably, said bin is pivotally mounted on said chassis for pivoting angular movement about a longitudinal axis between a transport position and a discharge position, said lid when in the open position is generally vertically oriented. 20 Brief Description of the Drawings A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Figure I is a schematic longitudinally extending perspective view of a road trailer; 25 Figure 2 is a schematic end perspective view of the trailer of Figure 1; Figure 3 is a further end perspective view of the trailer of Figure 1; Figure 4 is a schematic isometric view of portion of a lid assembly employed in the trailer of Figure 3; and Figure 5 is a schematic isometric view of an arm and linkage assembly employed 30 in the assembly of Figure 4.
4 Detailed Description of the Preferred Embodiment In the accompanying drawings there is schematically depicted a trailer 10 that would be typically a road trailer forming part of a road train. The trailer 10 includes a chassis 55 provided with wheel assemblies having transverse rotational axes. The trailer 5 10 includes a bin 11 mounted on the chassis 55, the bin 11 being of general rectangular form so as to have longitudinally extending side walls 12 and 13 and end walls 14. The walls 12, 13 and 14 provide a rectangular rim 15 that surrounds the top opening of the bin 11. The rim 15 includes longitudinally extending rim portions 16 and 17 located on opposite sides of the opening, and transverse rim portions 18 extending between the rim 1o portions 16 and 17. A floor 19 joins the walls 12, 13 and 14 so that the walls 12, 13 and 14 extend upwardly therefrom. Mounted on the bin 11 is a lid assembly 20 that includes a lid 21 that is movable between an open position and a closed position with respect to the open top of the bin 11. In the closed position the open top of the bin 11 is covered, while in the open position (as is illustrated in Figures 1, 2 and 3) the lid 21 is generally vertically oriented and located adjacent the side wall 13 and rim portion. The lid 21 has longitudinally extending edges 22 and transverse edges 23 and is generally rectangular in configuration. When in the open position the lid 21 is spaced from the side wall 13 so as to provide a longitudinal gap 24 to allow excess material to flow from the bin 11 during loading. 20 The lid 21 includes a frame 25 consisting of longitudinally extending beams 26 joined by diagonal brace members and transverse brace members 27. A stiff cover sheet (typical sheet metal) 56 is fixed to the frame 25 so as to be supported thereby. The frame 25 also includes end beams 28 to which the beams 26 are attached at their end extremities. 25 Each end beam 28 has operatively associated with it an arm 29. The arm 29 has a first end portion 31 and a second end portion 32. The beam 28 has end portions 33 and 34, with the end portion 31 being pivotally attached to the beam 28 intermediate the end portions 33 and 34 but spaced toward the end portion 33. The end portion 32 is pivotally attached to a mounting bracket 35 fixed to the bin 11. The end portion 31 is pivotally 30 attached to the beam 28 by a pivot 36 providing a pivot axis 37. The end portion 32 is pivotally attached to the mounting bracket 35 by a pivot 38 providing a pivot axis 39.
5 Also extending between the beam 28 and the mounting bracket 35 is a link 40, having an end portion 41 pivotally attached to the mounting bracket 35 by a pivot 42 providing a pivot axis 43. The link 40 also has an end portion 44 pivotally attaching the link 40 to the beam 28 via a pivot 45, providing a pivot axis 46. The axes 37, 39, 43 and 5 46 are generally parallel and extend longitudinally of the trailer 10. The pivot 45 is located intermediate the end portions 33 and 34 but is spaced toward the end portion 34. Accordingly the pivots 36 and 45 are spaced transversely of the trailer 10. The pivots 38 and 42 are also spaced transverse of the trailer 10, with the mounting bracket 30 being located adjacent the end wall 14 and rim portion 17. 10 A hydraulic ram 47 extends between a mounting bracket 48 (fixed to the bin 11) and the arm 29. More particularly hydraulic ram 47 is pivotally attached to the mounting bracket 48 by means of a pivot 49 providing a pivot axis 50. The ram 47 is also pivotally attached to the arm 29 by a pivot 51 providing a pivot axis 52. The axes 50 and 52 are parallel to the axes 37, 39, 43 and 46. The mounting bracket 48 is fixed to the bin 11 is adjacent the wall 14 and the rim portion 18. The pivot 52 is located intermediate the end portions 31 and 32. By the delivery of hydraulic fluid under pressure to the hydraulic ram 37, the arm 29 is caused to pivot about the axis 37, in turn causing the link 40 to pivot about the axis 43 and ultimately the beam 28 to move angularly between a first position at which 20 the lid assembly 20 closes the top of the bin 11, and a second position at which the lid 21 is located as best seen in Figures 1, 2 and 3, that is generally vertically oriented and located adjacent the rim portion 17. The bin 11 as mentioned previously is mounted on the chassis 55 and is pivotable about a longitudinal axis located adjacent the side wall 13. A hydraulic ram 53 25 extends between the chassis 55 and the bin II and is operable to cause tilting of the bin 11 to empty the bin 11. To provide for the delivery of material from the interior of the bin 11, the side wall 12 is pivotally attached adjacent the rim portion 17 to the end walls 14 so as to be movable to an open position. A hydraulic ram 54 causes pivoting movement of the side wall 12 between the open and closed positions thereof. 30 In the trailer 10, the pivots 36, 38, 42, 45, 49 and 51 are arranged generally in a single plane that is generally transverse of the trailer 10. As best seen in Figures I to 3, the lid 21 when in the open position is partly located lower than the rim portion 17.