CA2335413A1 - Hinge tank dual purpose trailer - Google Patents

Description

Hinge Tank Dual Puruose Trailer 1. Introduction This document exposes several different embodiments of a trailer-system that can haul a load of liquid cargo to a destination and then carry a substantial load of general cargo (or other kind of cargo) on the return trip. Tank trailers are often repositioned empty because there is no appropriate liquid cargo available for backhaul. General cargo, however, often is readily available for backhaul. The proposed trailer system is able to create overall productivity gains in such circumstances.

2. The Drawn Figures Fig 1 shows a side elevation view of a flatbed type tractor and double trailer combination used for over the road transportation. Fig 2 is a side elevation view of the preferred embodiment of the trailer-system innovation in what is termed the loaded-position.
Fig 3 is a side elevation view of the trailer-system innovation's preferred embodiment in what is termed the empty-position. Fig 4 shows a close up rear end elevation view of the trailer-system's preferred embodiment in the loaded-position. Fig 5 shows a close up side elevation view of the rear part of the trailer-system's preferred embodiment in the loaded-position. Fig 6 shows a close up side elevation view of the rear part of the trailer-system's preferred embodiment in the empty-position. Fig 7 shows a side elevation view of the innovation applied to a hopper type trailer embodiment of the innovation. All the figures are simplified representations. In some of them certain dimensions are exaggerated for descriptive clarity.
All these drawn figures are reintroduced in the appropriate sections of the description below.

3. The Preferred Embodiment The Typical B-Train Fig 1 shows a side elevation view of a flatbed type rig. It is a common tractor and double trailer combination used for over the road transportation. The trailer configuration shown is a typical b-train type. This figure is used to identify the standard truck and trailer parts that are also part of an innovative trailer system that is described further below.

The flatbed rig includes a tractor 2 (only the tractor-neck is showing in the figure), a front-trailer 3 and a rear-trailer 4. A tractor-neck 5 extends out from the tractor's 2 back end;
it is supported by a drive-tandem 6, the tractor's 2 power axles. A front-fifth-wheel 7, a common kind of kingpin hitch connection, is positioned connected to the tractar-neck's 5 top surface. Preferably, it is positioned about between the drive-tandem's 6 two axles.
The front-trailer 3 includes a front-platform 8, the front underside of which connects to the front-fifth-wheel 7. Of course, this kingpin connection allows the front-trailer 3 to pivot side to side in relation to the tractor 2. The rear underside of the front-platform 8 is supported by a center-tridem 9; this central three axle set is typical of most b-train type tractor trailer rigs. (Note that the centre beams and other structural members that support the front-platform 8 are included as part of the platform in this description and are not detailed in the figures.
The technology involved in their construction is well known).
The centre-tridem's 9 support beam extends backward out beyond the rear end of the front-platform 8. A rear-fifth-wheel 10 is positioned in about the top centre of this rearward extension of the beam. The rear-trailer 4 includes a rear-platform 11, the front underside of which connects to the rear-fifth-wheel 10. Of course, the rear-trailer 4 pivots side to side on this connection in relation to the front-trailer 3. A rear-tandem 12 supports the back end underside of the rear-platform 11. (Note that the centre beams and other structural members that on most trailers support the rear-platform 20 are included as part of it in this description and are not detailed in the figures).
From hereon in the description that follows, the term "trailer-platform" is used to refer to either one or the other of the front-platform 8 or the rear-platform 11.
The term "trailer-platforms" is used to refer to both these platforms in plural. No part number will follow the term in the text.
The Dual Purpose Trailer System Fig 2 is a side elevation view of a trailer-system 1 in what is termed from hereon to be the loaded-position. Fig 3 is a side elevation view of the trailer-system 1 in what is termed from hereon to be the empty-position. The trailer-system 1 is presented as a b-train tractor and trailer configuration, as was outlined above. However, the innovative features detailed in this document can also be applied to other configurations, including a-trains, c-trains, and other multiple trailer configurations, as well as to straight trucks, truck and trailer, and semitrailer rigs.
The loaded-position (as shown in Fig 2) is appropriate for when the trailer-system 1 is to be loaded with, to transport, and to be emptied of liquid cargo. The liquid cargo could be, for example, diesel fuel. The empty-position (as per Fig 3) is appropriate for when the trailer-system 1 is substantially empty of liquid cargo and is to be loaded with, to transport, and to be unloaded of general cargo. The general cargo could include pallets of plywood or dimensional lumber, for example.
In addition to the parts that correspond to a typical b-train tractor and trailer flatbed type rig, as detailed above and in Fig l, the trailer-system 1 also has the following parts that are detailed in Fig 2 and Fig 3 and describe in letters (a) through (e) below:
(a) A front-belly-tank 14 -An integral part of the front-trailer 3, it is positioned under the front-platform 8 behind the drive-tandem 6 and in front of the center-tridem 9. Preferably, it is made of metal, like steel or aluminium, and has a welded construction. Its front end must be set far enough back so as to not interfere with the drive-tandem 6 when the trailer-system 1 is taking corners. The front-belly-tank 14 is a fully closed liquid cargo transport tank fitted with appropriate parts and systems for loading, unloading, pressure and vacuum relief, vapour recovery, and access for cleaning, inspection, repair and maintenance as required. The construction of possum bellied tanks of this kind on trailers is known technology.
(b) A rear-belly-tank 15 -An integral part of the rear-trailer 4, it is positioned under the rear-platform I 1 behind the center-tridem 9 and in front of the rear-tandem 12. Preferably, it is made of metal, like steel or aluminium, and has a welded construction. Its front end must be set far enough back so as to not interfere with the center-tridem 9 when the trailer-system 1 is taking corners. The rear-belly-tank 15 is a fully closed liquid cargo transport tank fitted with the appropriate parts and systems for loading, unloading, pressure and vacuum relief, vapour recovery, and access for cleaning, inspection, repair and maintenance as required. Again, the construction of such possum bellied tanks is known technology.

4/ 14 (c) A series of hinge-tanks 16 -One of these tanks - and preferably there are four of them - is positioned toward the front end and the rear end of each of the trailer-platforms' top surfaces. Each hinge-tank 16 is a fully closed liquid cargo transport tank. It is fitted with appropriate parts and systems for loading, unloading, pressure and vacuum relief, vapour recovery, and access for cleaning, inspection, repair and maintenance as required. Preferably, it is made of metal, like steel or aluminium, and has a welded construction.
Each hinge-tank 16 can take on two positions. The first position is termed the horizontal-position, as shown in Fig 2, which corresponds to the trailer-system 1 being in the loaded-position. The hinge-tank 16 lies low and flat on the trailer-platform's top surface. The second position is termed the vertical-position, as shown in Fig 3, which corresponds to the trailer-system 1 being in the empty-position. In the vertical-positioned, the hinge-tank 16 is rotated up on a hinge-arrangement (this part is described in detail further below) until they are placed at about a 90-degree angle compared to the horizontal-position placement.
Preferably, in the vertical position, the hinge-tanks 16 will be positioned at the extreme ends of the trailer-platforms as Fig 3 shows, thus creating long spans of space in the centre of the trailer-platforms on which general cargo can be stowed. The hinge-tanks 16 are parts that can be connected to and separated from the trailer-platforms.
(d) A series of winch-towers 17 -One of these rigid vertical towers is position extending substantially vertically upward from the front end and the rear end of each of the trailer-platforms.
Preferably, there are four of them, one corresponding to each of the hinge-tanks 16. The winch-tower 17 corresponds to the hinge-tank 17 that is closest to it on the same trailer-platform.
(e) A series of winch-cables 18 -Each corresponding winch-tower 17 and hinge-tank 16 has a corresponding winch-cable 18. One end of this cable is connected to the top of the hinge-tank 16 toward the end that is furthest from the winch-tower 17. This connection is made in a way that permits it to be easily detached later, like a hook in a loop (not shown). The cable's other end is connect to a winch (describe in detail further below) that is positioned near the winch-tower's 17 base. The cable extends from the winch up and over a pulley (not shown) that :is position near the winch-

5/I4 tower's 17 tap and then out and down to where the cable connects to the hinge-tank 16.
Considering the hinge-tank 34 in the horizontal-position (as per Fig 2) when the winch draws in the winch-cable 18, the hinge-tank I6 will be rotated up on the hinge-arrangement until it is in the vertical-position (as per Fig 3). By letting out the winch-cable 18, the hinge-tank 16 can be lowered - rotating down on the hinge-arrangement - from the vertical position to the horizontal-position. An airbag (described later) is used to push over the tank from the vertical-position toward the horizontal-position. Thus by this automated means of moving the hinge-tanks 16 from the horizontal-position to the vertical-position and vice versa, the trailer-system 1 is converted from the loaded-position (which is appropriate for transporting liquid cargo) to the vertical-position (which is appropriate for transporting general cargo).
Close Up Figures Fig 4 shows a close up rear end elevation view of the trailer-system 1 in the loaded-position - the hinge-tank 34 that shows (the rearmost hinge-tank 34) is in the horizontal-position. Fig 5 shows a close up side elevation view of the rear part of the trailer-system I in the loaded-position. Only the rearmost hinge-tank 34 shows and it is in the horizontal-position. Fig 6 shows a close up side elevation view of the rear part of the trailer-system 1 in the empty-position. Only the rearmost hinge-tank 34 shows and it is in the vertical-position.
Hinge Tank Detail Preferably made of metal with welded construction, each of the hinge-tanks I 6 has a low profile, generally rounded rectangular shape when looked at from the rear end view in the horizontal-position (as per Fig 5). This profile should extend for substantially the tanks full length (except for perhaps the ends bulging out slightly). The tank in the horizontal-position (as per Fig 6) preferably is substantially longer than it is high, as this provides the tank loaded with liquid cargo a low centre of gravity for stable transport.
The hinge-tank's 16 liquid holding body is comprised of a series of walls, all of which have an inside surface and an outside surface. Each of these walls is detailed in letters (a) through (f) below:
(a) A bottom-wall 19 This wall is preferably substantially flat and rectangular in shape. Its outside surface rests on the trailer-platform's top surface when in the horizontal-position. Note that preferably a

6/14 cushioned-mat (not shown) is adhered to the bottom-wall's 19 outside surface;
it can be a sheet of rubber or sponge rubber, for example. It protects the bottom-wall 19, including from damage that might be caused by protrusions or imperfections in the trailer-platform's top surface.
(b) A pair of lower-curve-walls 20 One of these walls extends outward and upward in a curved shape from along the full length of each of the lateral edges of the bottom-wall 19. Preferably, the slope of the lower-curve-wall 20 becomes increasingly steep as it extends outward until about vertical. Both lower-curve-walls 20 extend upward to about the same height., and this height is about equal along their full length.
(c) A pair of side-walls 21 One of these walls extends about vertically upward from along the full length of the top edge of each of the lower-curve-walls 20. The two side-walls 21 extend upward to about the same height, and this height is about equal along their full length.
(d) A top-wall 22 This wall extends across connecting the top edges of the two side-walls 21.
The top-wall 22 has a somewhat arched shape. From along the entire top edge of each of the side-walls 21 it extends first upward and inward in a curve shape with an increasingly less steep slope, and then in a gentle upward and inward slope to its apex in about the centre between the two side-walk 21.
(A note aside - Described up to this point, in letters (a) through (d) above, the hinge-tank 16 is a rounded rectangular shaped tube, closed across the bottom, up the lateral sides and across the top. This tube is comprised of the continuum of the bottom-wall 19, the lower-curve-walls 20, the side-walls 21, and the top-wall 22. Described up to this point, however, this tube's ends are fully open).
(e) An inward-end-wall 23 This wall closes offthe end of the above mentioned tube furthest from the hinge-tank's 16 corresponding winch-tower 17 when in the horizontal position. Preferably, the inward-end-wall 23 will be either be substantially flat or have a slightly outward bulged shape.

7/ 14 (f) A tower-end-wall 24 This wall closes off the end of the tube mentioned above that is closest to the hinge-tank's 16 corresponding winch-tower 17 when the same hinge-tank 16 is in the horizontal-position. Preferably, this wall has a slightly outward bulge. It is best that this bulge is tapered from the sides toward the centre such that if the hinge-tank 16 is tilted up slightly from the horizontal-position in the direction of the vertical-position, the liquid cargo will flow by force of gravity to the bottom centre of the tower-end-wall 24.
Here ends the description of the walls that form the hinge-tank's 16 liquid retaining body.
Other hinge-tank 16 parts follow.
The hinge-tank's 16 discharge-valve is 25 is best fit through the bottom centre of the tower-end-wall 24. It is positioned so that if the hinge-tank 16 is rotated up slightly from the horizontal-position toward the vertical-position the liquid cargo will flow by force of gravity to this valve, thus facilitating the tank's full discharge.
Preferably, each hinge-tank 16 has a rollover-wall 26 positioned extending above the top-wall's 22 top centre. Preferably, the rollover-wall 26 is made of metal and is welded to the hinge-tank 16. It is a rigid ridge extending upward above the top-wall 22 surrounding, and providing rollover protection to, the required tank fixtures that are fixed through the top-wall 22 into the tank's liquid holding chamber. These fixtures can include some or all of the load port, the access hatch, the pressure vent, the vacuum vent, and vapour processing equipment or hook ups; other fixtures are also possible. The dimensions of the rollover-wall 26 have a specially relationship with the hinge-tank's 16 corresponding winch-tower 17.
This is described further below.
Winch System Detail Fig 4, Fig 5, and Fig 6 show that the winch-tower 17 is preferably comprised of two about vertical positioned tower-poles 27 that are connected, preferably by welding, by a series of about horizontally positioned crossbars 28. A series of tower-bolts 29 pass though the lowermost crossbar 28 connecting the winch-tower 17 to the trailer-platform's end.
A winch 30 is positioned connect to the top of the lowest most crossbar 28, preferably bolted to it. The winch-cable 18 extends up from the winch 30 and is guided over a pulley (not shown) positioned in about the centre of the uppermost crossbar 28. The pulley is

8/14 appropriately connected to the crossbar 28 so that it rotates substantially aligned with the trailer-system's 2 front to back direction. The winch-cable 18 passes over the pulley and extends down to where it is connected to the hinge-tank's 16 top-wall 22.
Preferably, the winch 30 is powered by an integrated electric motor. This motor receives its power from the trailer-system's 1 integrated electrical power means (far example, the tractor's 2 generator) to which it is connected by an appropriate electric cable. It is best that the connection allows for easy disconnection (such as the typical electrical plugs used on tractor and trailer rigs).
Because the winch-tower 17 is connected to the trailer-platform by the tower-bolts 29, if necessary or convenient for a given transport operation, the winch-tower 17 can be separated from the rest of the trailer-system 1. The winch 30 will need to be unplugged from the cable that connects it to the electrical power source and the winch-cable 18 will need to be disconnected from the hinge-tank 17.
The Hinge Arrangement Detail Each trailer-platform has a centre-span 31 across its centre length and an end-span 32 at either end. As the figures show, the centre-span's 31 top surface is slightly higher in elevation than the end-span's 32 top surface. At the intersection of these two spans is a short vertical wall. When the hinge-tank 16 is in the vertical-position, it sits with its tower-end-wall 24 facing down over the top surface of the end-span 32 (as Fig 6 shows). When the hinge-tank 16 is in the horizontal-position, its bottom-wall 19 rests on the top surface of the centre-span 31 (as Fig 5 shows).
A hinge-arrangement 33 is positioned on the end-span 32 right up against the short vertical wall where it intersects with the centre-span 31. The hinge-arrangement 33 is comprised of a set of platform-hinge-loops 34 that extend up from the end-span 32 and are connected to it by bolts or welding. A set of tank-hinge-loops 35 extend down from the hinge-tank 16 connected to it by welding near the intersection of the lower-curve-wall 20, the bottom-wall 19, and the tower-end-wall 24. The tank-hinge-loops 35 intersect with the platform-hinge-loops 34 to form a continuous tube typical of hinges. A hinge-pin 36 is fit though this pair of intersecting loops to complete the hinge-arrangement 33, Preferably, the hinge-pin 36 has an appropriate means (not shown) that connects it firmly in place so that it

9/ 14 will not shake loose during transport, and this means should allow for easy disconnection.
Thus, the hinge-pin 36 can be removed from the hinge-arrangement 33 and the hinge-tank 16 can be separated from the trailer-platform.
Preferably, as Fig 4 shows, there are two hinge-arrangements 33, one positioned near each lateral side of the trailer-platform and hinge-tank 16. The hinge-arrangements 33 allow the hinge-tank 16 to be rotated between the horizontal-position and the vertical-position. It also permits the hinge-tank 16 to be connected and disconnected from the trailer-platform - as the hinge-pin 36 can be remove and the platform-hinge-loops 34 and the tank-hinge-loops 35 separated from each other.
Hinge Tank Stowage In the horizontal-position (as per Fig 5), the hinge-arrangements 33 hold one end (that corresponding to the tower-end-wall 24) of the hinge-tank 16 firmly to the trailer-platform.
The hinge-tank's 16 other end (that corresponding to the inward-end-wall 23) is held down by a cargo-strap 37, connected to one side of the trailer-platform, loop over the tank's top, and connected to a ratchet 38 welded to the trailer-platform's other side. The ratchet 38 is tightened down to hold the hinge-tank 16 firmly in place. The same cargo-strap 37 and ratchet 38 can be used for the stowage of the general cargo.
An alternative to the cargo-strap 37 and ratchet 38, connector castings (like the corner castings typical of multimodal containers) can be welded the lower-curve-wall 20, positioned to intersect with turn-on-pins (like those typically used to connect multimodal containers to trailer to flatbeds and chassis) embedded in the trailer-platform.
In the vertical-position, the hinge-tank's 16 tower-end-wall 24 is facing downward toward the end-span's 32 the top surface. Its edge furthest from the winch-tower 17 (at the intersection of the bottom-wall 19 and the tower-end-wall 24) is connected firmly to the trailer-platform by the hinge-arrangements 33. The edge of the hinge-tank 16 that is right next to the winch-tower 17 (at the intersection of the top-wall 22 arid the tower-end-wall 24) is connected to the truck-platform on each side by a connector-clamp 39. These are welded to each side of the platform (thus preferably there are two connector-clamps 39 in total). Each of these clamps is positioned to hook into a connector-eye 40 that is welded to the hinge tank 16 (about at the intersection of the top-wall 22, the side-wall 21, and the tower-end-wall 24). The

10/14 connector-clamps 39 are tightened down to hold the hinge-tank 16 firmly to the trailer-platform.
Again, as an alternative to the connector-clamps 39 and connector-eyes 40, intersecting connector castings and turn-on-pins could be used to hold this edge of the hinge-tank 16 to the trailer-platform.
Considering the horizontal-position, preferably the connector-eyes 40 extend out toward the winch-tower 17 slightly beyond the most outward surface of the tower-end-wall 24. Preferably, each connector-eye 40 has a flat about vertical surface facing the winch-tower 17. Thus, when put into the vertical-position, these flat surfaces of the connector-eyes 40 will rest on the top surface of the end-span 32, supporting the hinge-tank 16.
To convert the hinge-tank 16 from the horizontal-position to the vertical-position, the cargo-strap 37, of course, must first be loosened and removed. Likewise, to convert the hinge-tank 16 from the vertical-position to the horizontal-position, the connector-clamps 39 must be loosed and disconnected from the connector-eyes 40.
The Winch Tower and Hinge Tank The dimension of the rollover-wall 26 and the spacing of the winch-tower's 17 tower-poles 27 and crossbars 28 preferably are such that when the hinge-tank 16 is in the vertical-position, the rollover-wall 26 will nest in the spacing between the tower-poles 27 and the crossbars 28.
Preferably, a rigid-plate 41, about vertically positioned, is welded between the tower-poles 27. An airbag 42 is appropriately connected to the rigid-plate 41 on the side facing the hinge-tank 16, so that when inflated with air it will expand out toward the hinge-tank 16. The airbag 42 has the appropriate valves and controls that permit it to be inflated and deflated with compressed air. An air-hose (not shown) connects it to the trailer-system's 1 integrated compressed air system, preferably by means that allows it to be easily disconnected later. The rigid-plate 41 and the airbag 42 are best positioned on the lower half of the winch-tower 17.
When the hinge-tank 16 is in the vertical-position, the airbag 42 is collapsed - empty of compressed air. When then inflated with compressed air, the airbag expands pushing on the hinge-tank'sl6 top-wall 22 - being obstructed in the opposite direction by the rigid-plate 41.
If the connector-clamps 39 are disconnected from the connector-eyes 40 and if the winch-

11/14 cable 18 is slackened enough; the airbag 42 will push over the hinge-tank 16.
In other words, it will push it sufficiently far out that the hinge-tank 16 (in the. vertical-position) will begin to fall - rotating on the hinge-arrangement 33 - under the force of gravity toward the horizontal-position. When converting from the vertical-position to the horizontal position, the descent of the hinge-tank'sl6 fall is controlled by slowly releasing the winch-cable 18.
Likewise, when converting from the horizontal-position to the vertical-position, the airbag 42 is slowly deflated, easing the hinge-tank 16 into its final placement. Preferably, the controls for the winch 30 and those for inflating and deflating the airbag 42 are located next to each other.
Flatbed Conversion Both the hinge-tanks 16 and the winch-towers 17 (with the winches 30 and the airbags 42 attached thereto) can be connected and disconnected from the rest of the trailer-system 1.
Thus, by removing these parts the trailer-system 1 can be converted for use as to a dedicated flatbed trailer (with the front-belly-tank 14 and the rear-belly-tank 1 ~
still available for liquid cargo). An appropriately sized plate (not shown), with the appropriate hinge loops and connector eyes, can be positioned over and connected to each of the end-spans 32, so the entire top surface of each the trailer-platform's are substantially level across their entire top surfaces.
Trailer System Operation The trailer-system 1 is put into the loaded-position to be loaded with, to transport and to be unloaded of liquid cargo. The liquid cargo of course is held in the hinge-tank 16 and the front-belly-tank 14 and the rear-belly-tank 15. To facilitate complete drainage of the hinge-tanks 16, the cargo-strap 37 can be removed from its inward end, and the hinge-tank 16 rotated slightly upward to facilitate complete drainage through the discharge-valve 25. Lifting the tank can be accomplished by winding in the winch-cable 18. Alternatively, a jack (not shown), preferably embedded in an appropriate inset in the inward-end-wall 24 can be used to elevate the hinge-tank's 16 end.
The trailer-system 1 is put into the empty-position when empty of liquid cargo and when it is to be loaded with, transport and unloaded of general cargo and the like. The general cargo being stowed on the top surface of the front-trailer's 3 and the rear-trailer's 4 centre-spans 31 between the hinge-tanks 16 in the vertical-position.

12/14 3. Alternative Embodiments No Belly Tanks The front-belly-tank 14 and the rear-belly-tank 15 can be absent of the trailer-system 1. The only tanks that hold liquid cargo are the hinge-tanks 16.
Van Trailer Embodiment The hinge-tanks 16 and all the parts and systems used to convert them from their horizontal-position to their vertical-position can be applied to a van type trailer. The van box has dimensions so that it does not obstruct the hinge-tank 16 in either position or when rotating between them. The van box preferably has side access to allow loading and unloading of the general cargo - a curtain sided van arrangement is a good way to accomplish this. The side access also allows access to the hinge-tanks' 16 from the inward-end-wall 23 to secure it into the horizontal-position. The van box is also equipped with front and back end doors for access to discharge-valves 25 for unloading and to secure the tanks into the vertical-position.
The winch-towers 17 are preferably inside the van box when these front and back end doors are closed.
Hopper Trailer Embodiment Fig 7 shows a side elevation view of the innovation can applied to a hopper-trailer-system 43 with its unloading shoots positioned at the bottom between the axle sets. The front-trailer's 3 hinge-tanks 16 are in the vertical-position, and the rear-trailer's 4 hinge-tanks 16 are in the horizontal-position. Instead of the hinge-tank 16 itself being connected to the hinge-arrangement 33, the tank is fixed to a hinged-door 44. This door is slightly wider than the hinge-tank 16. In the vertical-position the hinge-door 44 seals a hopper-box 45 at the end so that the granule product loaded therein cannot escape. In the horizontal-position, the hinged-door 44 is supported by and appropriately connected to a cross-brace 46 that runs from side to side across the hopper box and is preferably welded to its structure. The hinge-tank 16, of course, is supported on the hinged-door 44 in the horizontal-position. The cross-braces 46 are preferably made of metal and have the shape of an inverted "u". In the horizontal-position, the end of the hinged-door's 44 bottom surface furthest from the winch-tower 17 sits on the cross-brace's 46 top. A series of straps (not shown) with an appropriate hooks are hooked under the

13/14 cross-brace's 46 lower lip on one end and tightened by ratchet devices (not shown) on the other end. These ratchet devices being welded to the hinge-tank'sl6 top-wall 22 near the intersection with the inward-end-wall 23. The hopper-trailer-system 43 operator attaches and detaches the straps to the cross-braces 46 by climbing atop the hinge-tank 16 in the horizontal position.
One Level Flatbed The hinge-arrangement's 16 platform-hinge-loops 34 can be bolted or welded to a regular flatbed platform that is substantially level from end to end. In other words, a platform without the different levels between the centre-spans 31 and the end-spans 32.
The position of the hinge-arrangements 33 and the connector-eyes 40 visa vie the trailer-platform is such that the bottom-wall 19 is supported by the trailer-platform in the horizontal-position and the hinge-tank 16 rests, supported by the connector-eyes 40 in the vertical-position.
Detachable Framework The platform-hinge-loops 34 can alternatively be part of a welded framework that is connected and disconnected from the trailer-platform. This framework includes the winch-tower 17 and associated parts. The framework is comprised of a lateral beam that crosses from side to side at the end of the trailer-platform's top surface. The winch-tower 17 extends upward out of the centre of this lateral beam. A forward beam extends from each end of the lateral beam, along each side of the trailer-platform's top surface toward its opposite end. The platform-hinge-loops 34 are positioned welded to the ends of these forward beams farthest from the winch-tower 17. The connector-clamps 39 used to hold the hinge-tank 16 in the vertical-position are also welded to the forward beams close to their intersections with the lateral beam. The framework is connected to the trailer-platform by a series of turn-on-pins that intersect with appropriate openings in the lateral beam and the forward beam so that the framework can be connected and disconnected from the trailer-platform. When in the vertical-position, the framework, the hinge-tank 16 and the winch-tower 17 can be separated as a unit from the rest of the trailer-system 1.
Sliding Hinge Arrangements A further variation of the framework describe in the paragraph immediately above is for the platform-hinge-loops 44 to be positioned welded to a sliding bar that crosses between

14/14 the two forward beams. A set of upper and lower rails are set into the inside walls of the forward beams and run fox much of their length, and a rotating wheel is positioned on either end of the sliding bar. The rotating wheels are designed to intersect with the upper and lower rails and roll on them being guided by them. The sliding bar can be pinned in place in at least two positions along the length of the upper and lower rails. This wheel and rail arrangement allows the hinge-tank 16 in the horizontal-position to be moved closer to the winch-tower 17 compared to in the preferred embodiment. In some cases this can permit a better distribution of the liquid cargo's weight over the trailer's axle sets. It also permits the hinge-tanks 16 to be longer (from the inward-end-wall 23 to the tower-end-wall 24) and/or higher (from the bottom-wall 19 to the top-wall 22) in relation to the trailer-platform's total length. To facilitate rolling the hinge-tank 16 forward and backward along using the wheel and rail arrangement, a downward extending jack with a wheel on its lower end can be positioned connected to the inward-end-wall 23. When the jack is extended downward it lifts that end of the tank slightly above the trailer-platform's top surface, permitting the empty tank to be easily moved forward and backward.
Alternate Fluid Cargoes Alternative to liquid cargo, the hinge-tanks 34 can be designed to hold other kinds of fluid cargoes including powders and gaseous fluids.

Claims