GB2409852A - Trailers with spring biassed container holding arms - Google Patents

Abstract

The present invention relates to a trailer (1,201) for carrying containerised loads, comprising a chassis section (2,202) formed utilising two substantially parallel elongate members (4,204), and one or more support members (40,240) for supporting the containerised load. The or each support member (40,240) is movable between a first position in which the support member is stowed between the elongate members (4,204) when not in use to support a containerised load, and a second position (43, Fig 2A or 241') in which the support member extends away from the elongate members (4,204) for supporting said containerised load. The trailer (201) comprises a biasing means (44,91) which partially relieves the weight of the support member (40,240) when in the first position and/or when in the second position (43,241'). Preferably, the arms are supported when inboard by transverse chassis members and the bias is preferably a coil spring which is connected between an arm and the chassis member.

Description

4 : : - 1- 2409852 Trailers for Carrying Containerised Loads The

present invention relates to trailers for carrying containerized loads.

Flatbed and skeletal trailers often have a rear sliding bogie section that allows the trailers to be extendible between two lengths, for example 6.lm (20 feet) and 12.2 m (40 feet). In one mode of usage, the length of the trailer is locked at either of these lengths for mounting of containers with these lengths. A 13.6 m (45 feet) container may also be carried on a 12.2 m trailer. Alternatively, the length of the trailer may be locked in the extended position to permit greater axle loading, according to the law. For example, a 6.1 m (20 feet) container above a certain weight may be required by law to be carried by a 12.2 m trailer in order to spread the axle loading.

The extension may be accomplished by having the set of wheels on a bogie which is itself fixed to a slider mechanism for slidably moving the bogie relative to the chassis section.

Extendible trailers allow a driver to load various types of ISO container configurations, namely 1 x 12.2 m (40 feet) container standard or "High Cube" height, 1 x 13.6 m (45 feet) container standard or "High Cube" height, 1 x 9.1 m (30 feet) container, 1 x 6.1 m (20 feet) "Heavy" (at least 24 tonne) container standard or "High Cube" height placed in the centre of the trailer for axle loading laws and 2 x 6.1 m (20 feet) containers standard or "High Cube" height. The containers are collected from the docks and given to the operators for delivery. Due to nature of the work the haulier . . . . . does not know in advance which type of container he may have to carry for the next delivery.

When the trailer is extended, it is able to carry all of the above container sizes, however the "Heavy" 6.1 m container must be centrally mounted in order to comply with axle loading laws. In the extended position, the rear "Heavy" 6.1 m container doors cannot be accessed for unloading without retracting the trailer into the closed position. To close the trailer the driver can operate the locking mechanism from his cab to unlock the section, and then with the rear wheels locked, reverse the cab into its retracted position, closing the trailer fully allowing the container doors to become flush with the rear of the trailer for off loading.

A number of problems arise from requirement to carry a variety of container types, particularly but not exclusively with such sliding bogie trailers. Firstly, this type of trailer is not able to carry all container configurations, loaded and unloaded, legally in compliance with both UK and Continental European axle and height laws. The UK and Continental European road haulage industry standard generally insists, due to cost and breakdown availability, that sliding container chassis are operated on super single 385 x 65 x R22.5 Lyre size. This has split the UK and Continental European trailer manufactures into producing various types of the skeletal sliding bogie trailers. None of these variations has managed to overcome the divide. In Continental Europe there is a bridge height law setting a minimum clearance height of 4 m. As a result, the Continental European market requires what is known as a "Goose Neck" front to the trailer l ëeeëee - 3 - allowing a 13.6 m or 12.2 m (45 feet or 40 feet) "High Cube" container to sit lower on the chassis beams, thus reducing the container height by around 120 mm to 160 mm in order to get the overall height of the loaded container underneath the 4 m bridge clearance height. To comply with current Continental European laws and regulations, Continental European manufactures build sliding skeletal trailers with axle weight configurations that would not meet current British axle weight laws. The UK does not allow such low bridge heights on main routes, so it is not as beneficial to have a "Goose Neck" front to the trailer. Consequently, trailers for use in the UK are much cheaper to produce, and a "High Cube" container can be carried sitting on top of the trailer chassis as opposed to within the neck of a trailer chassis.

Many trailer manufactures have produced sliding bogie trailers with low profile, and consequently high cost, tyre sizes in order to overcome the problem of bridge clearance. A low profile Lyre means the UK trailer can then be built with a "Goose Neck" front whilst still allowing the 6.1 m (20 feet) "Heavy" container to travel to the rear. With the rear bogie section locked, the rear fixed twist lock beam is able to clear the spray suppression and axle assemblies. This is made possible owing to the low height of the wheel size.

Trailers with this lower axle / tyre size have not proved to be a success, and have become a costly alternative to obtaining a true UK/European sliding bogie skeletal trailer.

Low profile Lyres are not standard or widely available, and so a breakdown due to Lyre failure can result in lengthy delays while a replacement Lyre is located and fitted.

:e:.. e.e e.. :e.e - 4 Therefore, trailers that require an uncommon low profile tyre size are not economic for normal ISO container road haulage.

There is therefore a need for a UK/European trailer, and particularly an extendible trailer, that allows all container configurations, including "High Cube" containers. Such a trailer should ideally comply with all current axle weight laws including relevant bridge height legislation on the super single 385 x 65 x R22.5 Lyre size or equivalent, which is the industry standard low cost tyre specification.

One solution to these problems is disclosed in patent document WO 03/011636 Al. This document describes a trailer for carrying a containerized load, which comprises a chassis section formed utilising two substantially parallel elongate members, and one or more support members for supporting said containerized load. The support members are movable between a first position in which the support member is stowed between the elongate members when not in use to support a containerized load, and a second position in which the support member extends away from the elongate members for supporting said containerized load.

The trailer may be arranged to be extendible between extended and retracted positions by further comprising a sliding bogie.

The support members may then be moved into positions in which they may be used to support a containerized load, or stowed in positions where they are out of the way, allowing other support members and/or non-movable support members to be used, thus enabling the trailer to carry different c: e: e e' ë - 5 configurations of containerized loads.

To facilitate this, the support members when in the first position lie substantially at or below the level the elongate members between which the support member is stowed. The containerized load may then rest on the elongate members.

When the support members are fully below the elongate members, loaded containers may sit flush onto the top chassis beams.

Then, when the support members are in the second position, the support members lie substantially at or above the level of elongate members from which the support member extends.

The container may then more readily be secured to such a support in the second position.

Normally, there is at least one pair of such support members which when in the second position are arranged directly opposite each other with respect to a longitudinal central line of the elongate members. Such paired support members may then engage with directly opposite support points on an ISO containerized load.

The support members are then be arranged when in the second position to clear the trailer running gear, that is axles and tyres, when the paired elongate members are moved between extended and retracted positions.

In order to move between the first and second positions, each support member is arranged to pivot about an axis which lies below the level of the upper surface of the elongate members, for example by a pivot pin which extends through the support -eeecëe - 6 member.

Each support member therefore includes a pivot by which the support member is pivotably attached to the chassis and by which the support member may pivot between the first and second positions. An arm then extends between this pivot and a mounting point on the support member to which a containerized load may be secured when the support member is in the second position.

The arm may extend either diagonally with respect to the length of the elongate members when the support member is in the first position, or the arm may extend at right angles to the elongate members.

The invention is particularly useful with a so-called "Goose Neck" trailer for carrying a "High Cube" container, that is, a trailer having a forwards upwards rising section for connection to a tractor unit.

For reasons of safety and economy, it is desirable that the support member be moved manually between the first and second positions, rather than automatically under the action of a mechanical actuator. To maximize safety and convenience, each rotating support member may optionally have a handle for ease of operation.

A problem has been noted in use with such movable support members for containerized loads. In the United Kingdom, the standard height above the road of the upper surface of the longitudinal chassis members is about 1250 mm for a "Goose Neck" trailer. The distance between the outside edges of a e e e - 7 pair of longitudinal chassis members is about 1470 mm. The support members when in the stowed first position may reach to the centre-line between the paired longitudinal chassis members. In order to have sufficient strength to support a containerized load, each support member comprises approximately 25 kg of steel. The support member will normally have a handle or other such feature to facilitate lifting of the support member, and to provide a degree of leverage, this handle or feature must be provided substantially most of the way towards the end of the support member, i.e. near the longitudinal centre line of the trailer. The handle or lifting feature is therefore about 1000 mm to 1200 mm high and about 600 mm to 700 mm away relative to the person having to lift and rotate the support member into the second position. It is difficult even for a tall male driver to provide sufficient leverage to lift the support member. Furthermore, there is a temptation to drop to the support member either into the first position or the second position, which is potentially dangerous and may with time cause damage to the components of the support member.

It is an object of the present invention to address to provide a more convenient container support member for a trailer.

According to the invention, there is provided a trailer for carrying a containerized load, comprising a chassis section formed utilizing two substantially parallel elongate members, and one or more support members for supporting said containerized load, the or each support member being movable between a first position in which the support member is stowed between the elongate members when not in use to , - 8 - support a containerized load, and a second position in which the support member extends away from the elongate members for supporting said containerized load, wherein the trailer comprises a biasing means which partially relieves the weight of the support member when in the first position and/or when in the second position.

The biasing means may comprise a spring which stores energy as the support member is moved into the first position and/or the second position, and which releases said energy as the support member is moved to a position intermediate the first and second positions.

The biasing means may also comprise a spring, preferably a coil spring, that extends between the support member and a chassis member, such as a transverse chassis member, of the trailer.

The support member may have an arm which rotates about an axis when moved between the first and second positions, and the spring extends from the opposite side of said axis from said arm.

The spring may be arranged so that this is tensioned as the support member moves into the first position and/or the second position.

The spring may extend downwards from the support member to a fixing point on a chassis member.

In a preferred embodiment of the invention, the biasing means progressively relieves the weight of the support member as e cee cece 9 this is moved into the first position and/or the second position.

Also in a preferred embodiment, the support member when in the first position lies substantially at or below the level the elongate members between which said support member is stowed. The support member may, when in the second position, lie substantially at or above the level of elongate members from which said support member extends.

The support member when in said second position is supported by an elongate member.

The support member when in the first position is supported by a transverse chassis member.

The support member may be mounted so as to pivot between the first position and the second position.

The support member preferably includes a pivot by which the support member is pivotably attached to a trailer chassis and by which the support member may pivot between the first position and the second position, a mounting point to which a containerized load may be secured when the support member is in the second position, and an arm that extends between said pivot and said mounting point.

The arm may extend diagonally with respect to the length of the elongate members when said support member is in the first position. Alternatively, the arm may extend transversely to the length of the elongate members when said support member is in the second position. c: .

, . - 10 In a preferred embodiment of the invention, the arm pivots in a plane transverse to the length of the elongate members when moved between the first position and the second position.

In a preferred embodiment of the invention, a vehicle driver may move the arm manually between the first and second positions. Alternatively, the trailer may include at least one actuator by which the or each support member may be activated to move between the first and second positions. The actuator may be a hydraulically or pneumatically driven actuator, for example being extended and/or retracted by an air driven piston or diaphragm mechanism.

The trailer has mounting points for carrying containerized loads that cooperate with the or each support member to support the load when the support member(s) are in the second position.

The trailer may also comprise pullout or removable mounted twist lock beams for supporting a containerized load on top of the pullout or removable twist lock beams.

Also according to the invention there is provided a support member adapted for use in a trailer according to the invention.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figures 1A and 1B are, respectively, top and side plan |' :e: e V:.

views of a prior art extendible skeletal trailer, with the trailer in its extended position and showing three pairs of support members for supporting containerized loads laterally retracted within a pair of parallel main chassis members; Figures 2A and 2B are, respectively, top and side plan views of the trailer of Figure 1, with the trailer in its extended position and three pairs of support members in a laterally extended position so that these may connect to various sizes of container) Figures 3A and 3B are fragmentary perspective views of a second prior art trailer, similar to the trailer of Figures 1A-B and 2A-B but with support members that rotate between a stowed position to an extended position, through a plane that extends transverse to the longitudinal extent of elongate chassis members) Figures 4A, 4B and 4C show how each support member of the trailer of Figures 3A-B moves between, respectively, the extended and retracted positions, and particularly how each support member includes a telescopic arm that is shortened when stowed in the retracted position.

Figure 5 is a perspective view from above and to one side of a portion of a trailer according to the invention having container support members that have biasing means to relieve partially the weight of each support member when this is either a stowed position or an extended position; hi * t ' t; 8 t - 12 Figure 6 is a perspective view from above of the support members of Figure 5, showing how these rotate between the stowed and extended positions; Figure 7 is a perspective view from below of the trailer showing the biasing means, here a spring, and how this is affixed to the chassis of the trailer; Figures 8, 9 and 10 are perspective views from above and to the side of the support member of Figure 5, illustrating how the spring of the biasing means becomes extended when the support member is rotated to the extended position; and Figure 11 is a perspective view of the support member, showing how this is laterally extended when in the extended position so that a twist-lock mount may be positioned to engage with an ISO container.

Figures 1A, 1B, 2A, and 2B show a prior art extendible skeletal trailer 1 for carrying containerized loads, as described in patent document WO 03/011636 Al. The trailer 1 has a steel chassis section 2 with two main parallel elongate load bearing chassis members 4. The trailer 1 is a skeletal "Goose Neck" trailer, with the main beam 4 having a load bearing upper surface 6 set 160 mm below the level of two load bearing "Goose Neck" chassis members 8 that extend forwards of the main members 4. The main longitudinal chassis members have an outside-to-outside spacing of 1470 and have the upper surface 6 1250 mm above the level of the road. 13

Each of the pair of main chassis members 4 and forwards chassis members 8 are spaced apart by several transverse load bearing tie beams, including a forwards transverse beam 10 and a middle transverse beam 11 each of which extends laterally outside the parallel chassis members 4, 8 to support two corresponding pairs of standard twist lock mounts 14, 15 for connecting to various ISO standard containers.

The main chassis members 4 are in the form of steel I-beams or C-beams, which present an inwards facing C-section shape.

The trailer has a rear bogie section 18 with a pair of elongate parallel beams 20 that are nested inside and slidably retained in the C-section shape of the main chassis beams 4. A rearmost portion of the bogie section 18 has a transverse tie beam 12 which extends laterally outside the parallel chassis members 20 to support one corresponding pair of standard twist lock mounts 16 for connecting to the rearmost mounts of various ISO standard containers.

The main chassis section 2 has one transverse beam 22 from which projects a downwardly facing pin 24 that may engage with two opposed or inwardly facing clasp mechanisms 26 in the bogie section as the trailer chassis and bogie sections 2, 18 are moved relative to one another into an extended position, as shown in Figures 1A, 2A, 2A and 2B or a retracted position, as shown in Figures 3A, 3B, 4A and 4B.

The trailer 1 also has a forward transverse beam 28 from which projects a downwardly facing kin pin 30 for connection with a known fifth wheel on a tractor unit (not shown).

The bogie section 18 has conventional running gear including :. a, . . 1.. - 14

section 44 has a set of six wheels 32, three to a side, joined by three axles 33.

The front chassis has retractable support landing legs 34, shown in the down position, which would normally be in the up position if a tractor unit (not shown) were attached to the trailer 1.

So that the trailer may accommodate both 12.2 m and 13.6 m ISO containers, the rear transverse beam 12 and container mounts 16 of the bogie section 18 are on a sliding extension that can be moved between an extended position as shown in Figures 1A, 1B, 2A ad 2B, and a retracted position (not shown).

The main chassis section 2, has mounted within the elongate beams 4 six support members 40, arranged in three pairs 41, 42, 43 at forwards, middle and rear locations along the elongate members 4, for supporting various sized of containerized loads. As will be explained in more detail below, each one of the pairs may be moved between a retracted orientation, as indicated by unprimed reference numerals 41,42,43, and a laterally extended orientation, as indicated by primed reference numerals 41', 42', 43'.

Each support member 40 is elongate in form, having at one end a pivot 44 and at the other end a twist-lock mount 46 for an ISO standard container. An arm 48 extends between the pivot 44 and mount 46. The pivot has an axis 50 that is angled at 70 to the length of the arm 48.

Each support member 40 is pivotably connected to the main :e:. .. ail; :e ce.

chassis 2 at a right-angled corner formed between the elongate main beams 4 and transverse tie beams 47. When the support members 40 are connected to the main chassis 2 at a pivot mount 52, each pivot axis 50 is orientated at 45 to the length of the elongate chassis members 4. As a result, each support member is angled at 65 to the length of the elongate chassis members 4 when pivoted to lie between the chassis members 4. This angled orientation allows each support member 40 to be longer than half the distance between the opposite pairs of stowed support members 41,42,43, and as a result increases the reach of the laterally extended support members 41'42'43' so that these match the positions of ISO standard container mounts.

Each pivot mount 52 lies beneath the level of the upper surface 6 of the main chassis members 4. The support member pivot axis 50 lies to one side of the extent of the arm 48 so that when each support member 40 is retracted 41, 42, 43, the support member 40 lies fully beneath the level 6 of the main chassis members 4. The arrangement is such that when each support member if pivotably moved into the laterally extended orientation, each extended support member 41'42'43' is raised substantially above the level 6 of the main chassis members 4 so that a lower surface 54 of each arm 48 rests directly on the main chassis beam upper surface 6. The weight of a container connected to the support member twist locks 46 is then born by this contact between the arms 48 and main chassis beams 4, together with a restoring force provided through the pivot mounts 52.

The extended support members 41', 42', 43' are at a height which allows clearance for the running gear, including tyres :. :. .e ate :e ee. - 16

and any mud guards (not shown) to move longitudinally with respect to the extended support members 41', 42', 43'. The trailer described herein may use industry standard super single 385 x 65 x R22.5 Lyres, or an equivalent Lyre size.

According to ISO standards, the 31.6 m and 12.2 m "High Cube" containers have a forwards central raised floor section (not shown) into which the "Goose Neck" forward chassis members 8 are seated when such a container 61 is mounted to the trailer 1.

Reference is now made to Figures 3A and 3B, which show fragmentary perspective views of a second prior art trailer 101, also described in detail in patent document WO 03/011636 Al, in which components corresponding to those of the first prior art trailer 1 are indicated by reference numeral incremented by 100. The trailer 101 has a similar construction and operation to that of the first embodiment, and differs in the form of the support members 140.

The support members 140 are essentially linear, and have a pivot axis 150 which is at right angles to the length of a telescopically extendible arm 148. For clarity, Figures 3A and 3B omit a connecting pivot pin which secures each support member 140 to a pivot mount 152 at an adjacent transverse beam 147.

Each arm 148 is made from two telescopic steel sections 70,71: a hollow outer section 70 that has a box cross-section and which is integral with the pivot 144, and a hollow inner section that has a square "U" cross-section, the "U" being inverted when the arm 148 is extended as shown in Figures 3B : . .:e.:e 17 and 4A. The sections 70, 71 are slidably engaged and movable from a compressed orientation, in which the length of each arm 148 is sufficiently short so that a pair of opposed support members may be stowed between the parallel elongate main chassis members 104, to an expanded orientation, in which a container twist lock mount 146 at the end of each arm 148 is positioned to connect with a corresponding mount on an ISO container when the support member 140 is laterally extended.

The movement and expansion of the telescopic arms 148 is depicted in Figures 4A, 4B and 4C, as the support member is moved between an extended position as shown in Figure 4A to a retracted position as shown in Figure 4C.

In order to secure the telescopic arms 148 in a contracted or expanded orientation, each arm 148 has on an upper surface 75 of the inner telescopic section 71 a latch mechanism having an externally accessible sprung lever 72 that can be activated manually when the arm is rotated from within the main chassis section 102 to rest on an elongate chassis member 104. When the arm is moved between contracted and expanded orientations, the lever 72 slides in a slot 78 that extends through an upper surface 79 of the outer telescopic box section 70.

A free end 73 of the lever 72 can be pulled upwards or pushed down to raise or lower a transverse pin 74 that extends from an opposite end of the lever 72 through each telescopic section 70,71 of the arm 148. When the arm 148 is fully contracted or expanded, the pin 74 projects through one of two holes 80, 81 in a lower surface 77 of the outer : - ë -e telescopic box section 70 to hold these sections in place when the arm 148 is in the contracted or expanded orientations.

In order to provide a greater degree of longitudinal support to each of the six support members 140, six flanges 82 extend laterally away from the elongate main chassis member 104.

Each flange 82 is flush with the upper surface 106 of the elongate chassis member 104 from which it projects, and each has a through hole 84 that is aligned with the corresponding hole 81 in the outer telescopic section 70 when the arm is latched in the expanded orientation. The transverse pin 74 then extends into the flange through hole 84. In the event of sudden braking or an accident involving the trailer/tractor unit, the engagement of the transverse pins 74 in the through holes 84 provides additional longitudinal support to the support members 140 and hence the containerized load.

It should also be noted that the holes 80 in the outer telescopic sections 70 that correspond with the contracted orientation of each arm 148, are positioned to oppose the upper surfaces 106 of the elongate chassis members 104 when the arm is first rotated to rest on these chassis members, but prior to extension of the arms 148, as shown in Figure 4B. The pin when fully engaged in each hole 80, 81 projects beyond the outer telescopic section 70. As a result, when the arm 148 is oriented as shown in Figure 4B, the pin 74 comes into contact with the chassis upper surface 106 thus raising pin 74 and the lever 72, so partially disengaging the pin 74 from the hole 80 and making it easier for an operator to lift the lever 72 prior to pulling out the inner telescopic section 71 to expand the support member 140.

:-..

Although the first prior art support member 40 is

mechanically simpler than the second prior art support member 140, the second embodiment 140 provides the advantage of being lighter to manufacture than the first embodiment 40, which increases the load carrying ability of the trailer 101.

Reference is now made to Figures 5 to 11, which show various perspective views of a trailer 201 according to the invention, in which componentssimilar to those of the second prior art trailer 101 and support member 140 are indicated by reference numerals incremented by 100. The trailer 201 differs from the prior art 1, 101 in that each support member 240 has a biasing means 90 which partially relieves the weight of the support member 240 when the support member in the stowed position 241 and also when in the extended position 241'.

The biasing means 90 is formed from a steel double spring 91 having concentric inner and outer helical coils. This double concentric coil is a compact arrangement both in terms of length and diameter and provides a sufficient biasing force to relieve at least 70% and preferably 80% to 90% of the weight of the support member 240 when this is in both the stowed and extended positions. The double spring when relaxed is about 200 mm to 300 mm long and 40 mm in diameter.

The spring 91 is attached to the support member 240 at a bracket 92 which extends in the direction of the support arm 248 on the opposite side of the rotation axis 250 from the support arm 248 and twist-lock container mount 246. ëee - 20

The bracket 92 extends horizontally at a level about 50 mm below the level of the rotation axis 250 when the support member 240 is stowed 241 or extended 241', and the spring 91 extends downwards from the bracket 92 to a second bracket 93 on a transverse chassis member 247 at a level about 100 mm below the bottom of the longitudinal chassis members 204.

The double coil spring 91 is in tension when the support member is in the stowed or extended positions 241, 241', thus permitting the coil spring 91 to bear some of the weight of the support member 240. A driver may then more readily grasp a handle 95 provided at an end of the arm 248 and lift the support member 240 when this is in the stowed position 241.

As the support member 240 lifts, the spring 91 contracts and the biasing force provided decreases towards zero as the arm 248 extends vertically. This helps provided a smooth rotating movement 96 of the support member 240 as the biasing force declines as the weight of the support member is increasingly transferred to the pivot supports 244 during the movement of the support member towards vertical.

Then, as shown in Figures 8 and 9, the spring extends 97 under tension as the support member 240 moves to the extended position 241'. This relieves partially the weight of the support member making it much easier to move the support member into the extended position. Again the biasing force increases as relieve more weight as the support member becomes horizontal, thereby facilitating a smooth rotational movement.

If a driver drops the support member in either the extended 241' or stowed positions 241, the support member will fall i. .: .

* . . . - 21

gently into position. Optionally, as shown in Figure 6, a rubber bung 98 may be provided on a transverse support member to absorb any residual shock from dropping the support member 240 into the stowed position 241.

Once the support member 240 is in the extended position 241', then as shown in Figure 11 the support member 240 may be laterally extended in the same manner as described above in relation to the second prior art support member 140.

Although the biasing means 90 has been described in relation to a transverse rotating support member, this may be adapted also for use with a diagonal support member such as that described above.

It should be noted that the invention is not limited to trailers that may be combined with a tractor unit to form an articulated vehicle. For example, the invention is equally applicable to a trailer that includes an integral articulated or non-articulated motive unit. Therefore, the term "trailer" as utilised herein is intended to mean any form of movable support structure capable of supporting a freight container or tanker container for transportation and is not limited to a trailer arranged for use with a separate tractor unit or road going vehicle.

It should also be noted, that although the invention has been described in terms of a support member that is moved manually between the first and second positions, the invention may also provide benefits when the arm is moved under the action of a powered actuator. In this case, the spring biasing of the arm to relieve partially the weight of the arm in the -ëe first position and/or the second position will reduce the amount of mechanical effort that the actuator has to provide either when lifting or lowering the arm into one of the positions, and may also provide a smoother action and prevent sudden falling and bumping of the arm as the support member moves into the first and/or the second position.

Modifications may be incorporated without departing from the scope of the present invention as claimed. For example, although the invention has been described with reference to a sliding bogie trailer the invention is applicable to a standard single length trailer, although it may have particular advantages when utilised with a sliding bogie trailer. Similarly, although the invention has been described when used with a skeletal trailer, the invention may also be useful for flatbed trailers, or any trailer in which a section has a load bearing floor. - 23

Claims (20)

1. Claims 1. A trailer for carrying a containerized load, comprising a

   chassis section formed utilising two substantially parallel elongate members, and one or more support members for supporting said containerized load, the or each support member being movable between a first position in which the support member is stowed between the elongate members when not in use to support a containerized load, and a second position in which the support member extends away from the elongate members for supporting said containerized load, wherein the trailer comprises a biasing means which partially relieves the weight of the support member when in the first position and/or when in the second position.
2. 2. A trailer as claimed in claimed in Claim 1, in which the biasing means comprises a spring which stores energy as the support member is moved into the first position and/or the second position, and which releases said energy as the support member is moved to a position intermediate the first and second positions.
3. 3. A trailer as claimed in Claim 1 or Claim 2, in which the biasing means comprising a spring that extends between the support member and a chassis member of the trailer.
4. 4. A trailer as claimed in Claim 2 or Claim 3, in which the spring is a coil spring.
5. 5. A trailer as claimed in any of Claims 2 to 4, in which the support member has an arm which rotates about an axis when moved between the first and second positions, and the = - 24 spring extends from the opposite side of said axis from said arm.
6. 6. A trailer as claimed in any of Claims 2 to 5, in which the spring is tensioned as the support member moves into the first position and/or the second position.
7. 7. A trailer as claimed in any of Claims 2 to 6, in which the spring extends downwards from the support member to a fixing point on a chassis member.
8. 8. A trailer as claimed in any preceding claim, in which the biasing means progressively relieves the weight of the support member as this is moved into the first position and/or the second position.
9. 9. A trailer as claimed in any preceding claim, in which the or each support member when in the first position lies substantially at or below the level the elongate members between which said support member is stowed.
10. 10. A trailer as claimed in any preceding claim, in which the or each support member when in the second position lies substantially at or above the level of elongate members from which said support member extends.
11. 11. A trailer as claimed in any preceding claim, in which the or each support member when in said second position is supported by an elongate member.
12. 12. A trailer as claimed in any preceding claim, in which the or each support member when in the first position is - 25 supported by a transverse chassis member.
13. 13. A trailer as claimed in any preceding claim, in which the support member is mounted so as to pivot between the first position and the second position.
14. 14. A trailer as claimed in any preceding claim, which the or each support member includes a pivot by which the support member is pivotably attached to a trailer chassis and by which the support member may pivot between the first position and the second position, a mounting point to which a containerized load may be secured when the support member is in the second position, and an arm that extends between said pivot and said mounting point.
15. 15. A trailer as claimed in Claim 14, in which the arm extends diagonally with respect to the length of the elongate members when said support member is in the first position.
16. 16. A trailer as claimed in Claim 14, in which the arm extends transversely to the length of the elongate members when said support member is in the second position.
17. 17. A trailer as claimed in Claim 12 or Claim 16, in which the arm pivots in a plane transverse to the length of the elongate members when moved between the first position and the second position.
18. 18. A support member adapted for use in a trailer as claimed in any preceding claim.
19. 19. A trailer for carrying a containerized load, - 26 substantially as herein described, with reference to or as shown in Figures 5 to 11 of the accompanying drawings.
20. 20. A support member adapted for use in a trailer substantially as herein described, with reference to or as shown in Figures 5 to 11 of the accompanying drawings.