AU2016201024B2

AU2016201024B2 - Improved articulated vehicle

Info

Publication number: AU2016201024B2
Application number: AU2016201024A
Authority: AU
Inventors: Ian James Spark
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-03-01
Filing date: 2016-02-18
Publication date: 2020-06-04
Anticipated expiration: 2036-02-18
Also published as: AU2016201024A1

Abstract

CAP 2015900713 The principle of cooperative redundancy between two or more steering systems has been applied to dog trailers and road trains to eliminate scuffing and minimise off tracking (or corner cutting). In these truck/trailer trains slave reference points on the trailers are made to follow the path of a master reference point on the truck, irrespective of whether or not the truck/trailer train is in a steady state turn. A steady state turn is characterised by the truck and trailers all having the same instant centre which does not change with time. The system described for forward motion has been modified slightly to allow unskilled reversing of a train comprising many trailers. lo > ' ' U W ""\> w> N Ml AA. L' '\N N" ""N <NV', \V.~ I I .. '. .. .. .. .. . .. .. . ... .... .... .. .. ... .. . '. . ...... .. . .. . ... ... N. . .. .. .. . .. .. . '. . . . .. . . . .. . . . .. .. . .. . .. .. . .. . .. .. .. .. ... .. .. .. . .. . ... . . .. . . .. ......'. .. ... ... ... ... ... ... ... .. ... .. .. .. .. ... .. .. .. .. \N C. .. .. .. . .. .. .. .. . .. . . .. . . .. . .. t. .. . .. . .. .. . .. . .. . .. ..."'N'. .. .. .. .. .. . .. . . . . . . . . . . . . . . ....N. ...N. ...... ..... ..... .................. .. .. .. .. .. .. .. .. .. .. . .. .... ... .... . . .. .... .... .... .. . .. ........... .

Description

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AUSTRALIA Patents Act 1990

COMPLETE AFTER PROVISIONAL SPECIFICATION IMPROVED ARTICULATED VEHICLE

The invention is described in the following statement

IMPROVED ARTICULATED VEHICLE

Technical Field

The invention relates to articulated trains consisting of at least one truck and at least one trailer with wheels mounted at both the front and the rear (sometimes referred to as a dog trailer).

Prior Art

The Transport Industry Development Centre (TRIDEC) of Holland has developed a mechanical linkage system to reduce off tracking of semi trailers. This system uses the rotation of the first hitch point (located on the tractor or prime mover) to rotate the rearmost trailer axle by means of two longitudinal rods so that off-tracking of this axle is reduced. Rotation of this axle can be used to rotate other trailer axles so that these axles have a similar centre of curvature (COC) to the said rearmost tractor axle. Although this system may produce the correct angles for the trailer axles for steady state turns (where the tractor and trailer have the same COC), it does not produce the correct angles for the trailer axle or axles when the tractor and trailer are transitioning from one steady state turn to another.

Trackaxle (of Shepparton, Victoria) have developed a similar system to reduce off tracking and scuffing. Although this system may produce the correct angles for the trailer axles for steady state turns (where the tractor and trailer have the same COC), it does not produce the correct angles for the trailer axle or axles when the tractor and trailer are transitioning from one steady state turn to another.

Spark (Australian Patent Application 2010201258) has described and claimed a system that implements the correct wheel angles to eliminate both off tracking and scuffing even when a train of semi trailers is in transition from one steady state turn to another.

The current application describes a system that implements the correct wheel angles for dog trailers that eliminate both off tracking and scuffing for both a steady state and non steady state turn.

Note there are significant differences between dog trailers and semi trailers.

Semi trailers have their wheels concentrated at their rear, the front of the trailer being supported by the rear (drive) wheels of the tractor (also referred to as the prime mover). The tractor and semi trailer are connected at the hitch point which allows the trailer to rotate relative to the tractor around a vertical axis. In this case the hitch point is located just forward of the centre of the drive wheel set. In B Double semi trailer trains the front of the second trailer is supported by a hitch point that is just forward of the centre of the rear wheel set of the first trailer.

Each dog trailers consist of a 'semi trailer' and a dolly where the front of 'semi trailer' is supported by the dolly. The trailer can rotate with respect to the dolly around a vertical axis. The dolly is connected to the rear of a rigid truck by means of a drawbar. The front of the drawbar is connected to the truck behind the rear drive wheels by means of a pintle hitch with three degrees of rotational freedom. The rear of the drawbar is connected to the dolly by means of a horizontal hinge, so that only some of the weight of the drawbar is supported by the pintle hitch. A second dog trailer can be connected to the rear of the first dog trailer by means of a second pintle hitch.

Semi trailers tend to be used for loads with a lower density or for bulk liquids. Dog trailers tend to be used for higher density loads such as bulk solids. To facilitate the unloading of bulk materials the front of the trailer tub can be raised. Load dumping can also be achieved by raising one side of the tub. The tub of the truck can also be rotated to dump its load.

The problems to be solved

The solution uses the principle of cooperative redundancy to solve some of the problems inherent to trains consisting of one truck coupled to one or more dog trailers. The problems to be eliminated are as follows: 1. Off-tracking of some trailers (or axles), where the radius of curvature of the path of the trailing wheels is smaller than that of the leading wheels. 2. Scuffing of the wheels, where they are dragged across the ground at right angles to the plane of rotation. 3. Jack knifing of truck/dog trailer trains. 4. Difficulty of reversing trains of dog trailers.

The Solutions Proposed

The essential feature of the invention is that a point on the longitudinal axis of the truck is nominated as a master reference point (MRP) the locus of which creates a master path. Two slave reference points (SRPs) are located on the longitudinal axis of each trailer and these are made to follow the master path by control of angle of the trailer wheels relative to the longitudinal axis of the trailers. The angles of the drawbar connecting the trailer to the truck (or forward trailer) relative to the longitudinal axes of the connected bodies may also be controlled to reinforce the master path following effect.

The invention may be better understood with reference the following figures.

Figure shows a train where a truck tows two traditional dog trailers around a steady state turn.

Figure 2 shows a train where a truck tows three improved dog trailers with double dollies.

Figure 3 shows details of the means of controlling the angles of the trailer wheels and drawbars shown in Figure 2.

Figure 4 shows a train where a truck tows three improved dog trailers with double hinge drawbars.

Figure 5 shows details of the means of controlling the angles of the trailer wheels and drawbars shown in Figure 4.

Figure 6 shows an improved dog trailer with a single hinge reverse drawbar, which can also be described as an improved dog trailer with reverse single hinge (IDTRSH). As one articulation point has been eliminated it could also be regarded as an improved pig trailer.

Figure 7 shows an improved dog trailer with a conventional single hinge (IDTCSH). As one articulation point has been eliminated it could also be regarded as an improved pig trailer.

The problems inherent to trains consisting of one truck and one or more dog trailers can be solved as follows:

1. Reducing the Off Tracking of a train of Dog Trailers.

If a train of one truck 1 and several traditional dog trailers 2 and 3 are moving in a straight line, they will all have a centre of curvature (COC) perpendicular to their motion located at infinity. If the radius of curvature of the truck is reduced to a finite value, the radius of curvature of the dog trailers will progressively reduce until the truck and trailers eventually achieve the same centre of curvature 4. When the whole train has the same centre of curvature, the shape of the train becomes stable and the turn is in a steady state. See Fig 1.

It can be seem from Figure 1 that the swept path of the rear inside wheel 5 of the first dog trailer is inside the swept path of the swept path of the inner drive wheel 6 of the truck. The swept path of the rear inside wheel 7 of the second dog trailer is further inside the swept path of the swept path of the inner drive wheel 6 of the truck. No more dog trailers could be added to this train as it is no longer possible for the axis of the rear axle of the third dog trailer to pass through the common centre of curvature 4.

Figure 2 shows a train of modified dog trailers 8,9 and 10 where the front dolly 11 is not fixed at right angles to the drawbar 12 and the fixed axle at the rear of the dog trailer is replaced with a dolly 13. The front and rear dollies on each modified dog trailer can be positively rotated by means of control systems. In Figure 2 the pintle hitch of the truck is nominated as the master reference point 14, the locus of which becomes the master path. The pivot points of the two dollies on each trailer are nominated as the slave reference points 15 to 20 which are made to follow the master path. This improved dog trailer is referred to as the improved dog trailer with double dollies (IDTDD).

The curvature Kof the path of the midpoint of the drive wheels of the truck is approximately proportional to the rotation of the steering wheel, where KIS the reciprocal of the radius of curvature (ROC). From the variation Kand the speed of the truck with respect to time the trajectory of the master reference point can be calculated by an on-board computer by integrating the Serret-Frenet equations. From this trajectory the angles of the trailer wheels required to keep the slave reference points on the master path can be calculated and implemented by a control system. The on-board computer can also calculate the angle of the drawbar relative to the axes of the rearward trailer and the forward truck or trailer required to keep the slave reference points on the master path. Note that this technique works for all turns; not just steady state turns.

The dollies11 and 13 can be rotated to the correct angles by means of two hydraulic rams. Figure 3 shows these rams. Rams Al and A2 control the angle of the rear dolly, whereas Rams B1 and B2 control the angle of the front dolly. In principle control of these rams is sufficient to ensure that the slave reference points follow the master path. However if rams C1 and C2 are activated and controlled to enforce the correct angle between the longitudinal axis of the trailer and the forward drawbar, one level of cooperative redundancy results. This means that if one trailer steering system starts to fail it is backed up (or reinforced) by the second system. This should make the jack knifing of the truck trailer train more difficult. If rams D1 and D2 are also activated and controlled so as to enforce the correct angle between the longitudinal axis of the truck 1 (or forward trailer) and the rearward drawbar 21, a second level of cooperative redundancy will result. With two levels of cooperative redundancy the truck/trailer couple becomes a rigid structure (with respect to the plan view) so jack knifing should now be impossible.

Figure 4 shows a modification of the improved dog trailer shown in Figure 2 where the dollies at the front and rear of the trailer are replaced with axles 22 and 23 that are fixed perpendicular to the longitudinal axis of each trailer. Steerable wheels are attached by means of approximately vertical kingpins. In this case the rear end of the drawbar 24 is attached to the front of the trailer 25 with a coupling with two rotational degrees of freedom. One degree of freedom is about a vertical axis and the other about a transverse horizontal axis. This trailer is referred to as an Improved Dog Trailer with a Double Hinge drawbar (IDTDH). Details of the means of controlling the angles of the trailer wheels are shown in Figure 5. Hydraulic rams Al and A2 are used to control the angles of the rear wheels 25 and 26, whereas hydraulic rams B1 and B2 are used to control the angles of the front wheels 27 and 28. In principle control of these rams is sufficient to ensure that the slave reference points follow the master path. However if rams C1 and C2 are activated and controlled to enforce the correct angle between the longitudinal axis of the trailer and the forward drawbar, one level of cooperative redundancy results. This means that if one trailer steering system starts to fail it is backed up (or reinforced) by the second system. This should make the jack knifing of the truck trailer train more difficult. If rams D1 and D2 are also activated and controlled so as to enforce the correct angle between the longitudinal axis of the truck 1 (or forward trailer) and the rearward drawbar 29, a second level of cooperative redundancy will result. With two levels of cooperative redundancy the truck/trailer couple becomes a rigid structure (with respect to the plan view) so jack knifing should now be impossible.

In Figures 4 and 5 the master reference point is the pintle hitch at the rear of the truck and the slave reference points are the vertical hinge at the rear of the drawbar and the pintle hitch at the rear of each trailer. A disadvantage of this configuration is the path of midpoint of the right side of the trailer passes inside the path of the right drive wheel of the truck. This problem can be overcome by moving the master reference point further away from the midpoint of the drive wheels of the truck (while remaining on the longitudinal axis of the truck)

A special case arises if the distance of the master reference behind the midpoint of the truck drive wheels is equal to the sum of distance of the pintle hitch behind the midpoint of the truck drive wheels and the length of the double hinge drawbar. In this case the master reference point must be coincident with the first slave reference point. This means that the drawbar 30 is an extension of longitudinal axis of the truck. This arrangement is shown in Figure 6 and can be referred to an Improved Dog Trailer with a Reverse Single Hinge drawbar (IDTRSH). It could also be referred to an improved dog trailer with a Reverse Drawbar. Whereas the drawbar of a traditional dog trailer is connected to the dolly with a transverse horizontal hinge, in the case of the reverse drawbar dog trailer the drawbar 30 is attached to the rear of the truck with a transverse horizontal hinge. Note that all following trailers must be attached with the double hinge 31 drawbar.

Fig 7 shows an improved dog trailer with at least two fixed axles with steerable wheels. In this case the master reference point is the pintle hitch at the rear of the truck. The first slave reference point (SRP1) is eliminated by making it coincident with the master reference point. This arrangement can be referred to as an Improved Dog Trailer with Conventional Single Hinge (IDTCSH). The improved dog trailers shown in figs 6 and 7 can also be designated as improved pig trailers as one articulation point has been eliminated.

An alternative means of ensuring that the path of the midpoint of the right side of the trailer does not pass inside the path of the right drive wheel of the truck is to make the pintle hitch of the truck the master reference point (as for the IDTDD) but make the slave reference points the intersections of the front and rear trailer axles with the longitudinal axis of each trailer.

2. Elimination of scuffing

The load carrying capacity of dog trailers can be increased by adding more axles to the trailer. However adding parallel axles with un-steered wheels produces a scuffing problem on turning because the rotational axes of all the wheels on each trailer cannot intersect at a single point. However for the IDTDD trailers shown in Figures 2 and 3 more dollies could be mounted between the front and rear dollies where the angle of the dollies is positively controlled to ensure that the rotational axes of all wheels intersect at a single point.

Similarly for the IDTDH trailers shown in Figures 4 and 5 more fixed axles 32, 33 and 34 with steerable wheels can be added where the wheel angles are controlled to give a single centre of curvature for all wheels. In Figure 4 only two axles are shown in the first trailer, four axles in the second trailer and five axles in the third trailer. The elimination of scuffing minimises road damage, tyre wear and fuel consumption. It should be noted that although wheels located midway between the forward and rearward slave reference points of a trailer do not need to be steered for steady state curves, this is not the case for non steady state turns. Figure 4 also shows that the single drive axle 35 of the truck can be replaced with a double drive axle 36.

3. Increasing resistance to jack knifing.

Section 3 above shows that if the angle of the draw bar relative to the longitudinal axis of the trailer is positively controlled to duplicate the steering effect of the trailer wheel angles, jack knifing should be more difficult. If the angle of the drawbar relative to the longitudinal axis of the truck is also positively controlled to triplicate the steering effect of the trailer wheel angles, then jack knifing should be impossible.

4. Easy reversing of truck dog trailer trains.

If the train is to be reversed the master reference point needs to be temporarily re-located to the rear of the last trailer 37. The slave reference points are the remaining slave reference and the master reference point for forward motion. The driver then steers the last trailer with the aid of a reversing camera and reversing joystick (or other interface). The control system then ensures that the slave reference points follow the reverse master path. Note that in this case the truck must also be steered automatically to ensure that the last slave reference point also follows the master path.

Note that the hydraulic rams used to control the trailer wheel angles and hitch angles could be replaced with electric screw actuators.

Editorial Note 2016201024

The paging numbering is non sequential overlapping of Description pages 1-6 and claims pages 1-3 requested to be included for assembly of this case. Claims pages should be 7-9

Claims

The claims defining the invention are:

1. A train consisting of truck and one or more trailers where the path of the truck is determined by the driver with a steering wheel which controls the angles of the front wheels relative to the longitudinal axis of the truck, where a point on this longitudinal axis is nominated as the master reference point, the locus of which defines the master path which two slave reference points located on the longitudinal axis of each trailer are made to follow, by positively controlling the angles of each trailer wheel relative to the longitudinal axis of each trailer, where each trailer has a minimum of four wheels where two or more are located at the front and two or more are located at the rear, where each trailer is connected to the truck or trailer in front by means of a drawbar, where the location of the instant centres of one or more trailers that are required to keep the slave reference points on the master path are determined by numerical means where the trailers are transitioning from one instant centre to another instant centre, where the location of the individual instant centres is used to calculate the trailer wheel angles required to keep the slave reference points on the master path, hereafter referred to as the correct wheel angles.

2. A train according to claim 1 where the angles of the front wheels of the truck and the speed of the truck are sampled at regular intervals and used to determine discrete points on the path of the master reference point, from which the required position of the slave reference points on the longitudinal axis of each trailer is determined, and from the latter the instant centre of each trailer, and the required angles for the trailer wheels can be calculated trigonometrically at the same time intervals.

3. A train according to any one of claims 1 or 2 where the trailer wheels are steered by locating them at the ends of a coaxial axle where this axle is mounted on a dolly which can be positively rotated about a vertical axis located on the longitudinal axis of the trailer, where this rotation ensures that the slave reference points move along the master path.

4. A train according to claims 1 or 2 where the trailer wheels are steered by locating them at the ends of axles that are fixed at right angles to the longitudinal axis of the trailer and where the wheels are connected to these fixed axles by means of kingpins where the axis of each kingpin is approximately vertical, where the wheels can be positively rotated about the kingpin axis, where this rotation ensures that the slave reference points move along the master path.

5. A train according to claim 3 where the drawbar is connected to the truck or forward trailer with a coupling that allows three degrees of rotational freedom, where the rear of the drawbar is connected to the trailer by a coupling which has one degree of rotational freedom about the vertical axis of the dolly, where the drawbar has a hinge with a horizontal axis located towards its rear end.

6. A train according to claim 4 where the drawbar is connected to the truck or forward trailer with a coupling that allows three degrees of rotational freedom, where the rear of the drawbar is connected to the trailer by a coupling which has one degree of rotational freedom about a vertical axis on the longitudinal axis of the trailer, where the drawbar has a hinge with a horizontal axis located towards its rear end.

7. A train according to claim 5 where the angle between the longitudinal axes of the drawbar and the trailer is positively controlled by one ore more hydraulic rams, where one end of the rams is connected to the drawbar and the other is connected to the front of the trailer, where these rams also ensure that the slave reference points follow the master path to produce one level of cooperative redundancy.

8. A train according to claim 6 where the angle between the longitudinal axes of the drawbar and the trailer is positively controlled by one or more hydraulic rams, where one end of the rams is connected to the drawbar and the other is connected to the front of the trailer, where these rams ensure that the slave reference points follow the master path to produce one level of cooperative redundancy.

9. A train according to claim 7 where the angle between the longitudinal axes of the drawbar and the truck or forward trailer is positively controlled by one or more hydraulic rams, where one end of these rams is connected to the drawbar and the other is connected to the rear of the truck or forward trailer, where these rams also ensure that the slave reference points follow the master path to produce a second level of cooperative redundancy.

10. A train according to claim 8 where the angle between the longitudinal axes of the drawbar and the truck or forward trailer is positively controlled by one or more hydraulic rams, where one end of these rams is connected to the drawbar and the other is connected to the rear of the rear of the truck or forward trailer, where these rams also ensure that the slave reference points follow the master path to produce a second level of cooperative redundancy.

11. A train according to claims 1, 2, 3, 5, 7 or 9 where additional wheels are added to the trailers but these are positively steered to ensure that rotational axes of all wheels intersect at a single point.

12. A train according to claims 1, 2, 3, 4, 6, 8 or 10 where additional wheels are added to the trailers but these are positively steered to ensure that rotational axes of all wheels intersect at a single point.

13. A train according to any one of claims 1 to 12 where the master reference point is the point where the drawbar connects to the rear of the truck.

14. A train according to claims 3, 5, 7 or 9 where the slave reference points are the vertical axes of the dollies.

15. A train according to claims 4, 6, 8 or 10 where the slave reference points are the pivot points where the drawbars connect to the trailers.

16. A train according to claims 4, 6, 8, 10 or 12 where the master reference point is located on the longitudinal axis of the truck forward of the midpoint of the drive wheels.

17. A train according to claims 4, 6, 8, 10 or 12 where the master reference point is located on the longitudinal axis of the truck rearward of the midpoint of the drive wheels.

18. A train according to claim 17 where the first slave reference point on the first trailer is effectively eliminated by making it coincide the master reference point of the truck, so that a reverse drawbar is required which is attached to the rear of the truck by means of a horizontal hinge.

19. A train according to claim 17 where the master reference point is the truck hitch point and this is coincident with the first slave reference point at the front of the first trailer, so that a normal drawbar is required which is attached to the front of the trailer by means of a horizontal hinge.

20. A train according to any one of claims 1-17 consisting of one or more trailers being pushed by a reversing truck where the path of the rearmost trailer is determined by the driver with an auxiliary steering wheel or joystick which controls the angles of the rearmost wheels relative to the longitudinal axis of the trailer, where a point on this longitudinal axis is nominated as the master reference point , the locus of which defines the master path which one slave reference point located on the longitudinal axis of the last trailer and two slave reference points on every other trailer are made to follow, by positively controlling the angles of each trailer wheel relative to the longitudinal axis of each trailer and the angles of the front wheels of the reversing truck, where each trailer has a minimum of four wheels where two or more are located at the front and two or more are located at the rear, where each trailer is connected to the truck or trailer in front by means of a drawbar.

21. A train according to any one of claims 18 to 19 consisting of one or more trailers being pushed by a reversing truck where the path of the rearmost trailer is determined by the driver with an auxiliary steering wheel or joystick which controls the angles of the rearmost wheels relative to the longitudinal axis of the trailer, where a point on this longitudinal axis is nominated as the master reference point , the locus of which defines the master path which one slave reference point located on the longitudinal axis of the last trailer and two slave reference points on every other trailer are made to follow, by positively controlling the angles of each trailer wheel relative to the longitudinal axis of each trailer and the angles of the front wheels of the reversing truck, where each trailer has a minimum of four wheels where two or more are located at the front and two or more are located at the rear, where each trailer is connected to the truck or trailer in front by means of a drawbar.

22. A train according to claims 1-21 where the hitch angles between the truck and the following trailer and between successive trailers is positively controlled by hydraulic rams or screw actuators to independently cause the slave reference points to follow the master path selected by the driver.