Trailer for transporting containers, which is provided with transverse positioning means
The present invention relates to a trailer for transporting containers, wherein the trailer is provided with: - at least one pair of wheels, coupling means, mounted at the front thereof, for coupling to a tractor, which coupling means, when coupled to the tractor, allow rotation about an essentially vertical coupling axis of rotation, hauling means suitable for allowing the container to be pulled onto the trailer from the rear end of the trailer in the longitudinal direction thereof.
Trailers of this type are generally known and are widely used for the transport of containers, such as, for example, sea freight containers. Such containers generally have lengths of 20, 30 or 40 feet. Trailers of this type are furthermore provided with hauling means, by means of which a container set down at the rear of the trailer can be pulled onto the trailer in the longitudinal direction of the trailer. To this end the trailer is frequently also provided with a tilting mechanism in order to tilt the trailer, while the latter is coupled to the tractor/the towing vehicle, in such a way that the rear end of the trailer comes into contact with the ground. This appreciably facilitates hauling of the container onto the trailer. The Applicant markets trailers of this type and has various patents for trailers provided with such hauling means and tilting mechanisms, such as European Patent EP-B 0 723 505, which relates to a trailer combination provided with hauling means and a tilting mechanism.
One problem with trailers of this type is that if the trailer is not positioned accurately enough with its rear end by the container, in general by a head end thereof, the container has to be lifted and moved again or the trailer has to be driven into position again by driving forward and reversing. Both positioning operations are time-consuming. The abovementioned EP-B 0 723 505 discloses rollers which are movable up and down and are mounted by the rearmost pair of wheels, which rollers enable fine positioning of the trailer combination. Said rollers have axes of rotation which run in the transverse direction of the trailer at an angle of approximately 8° with respect to the wheel axles. A slight lateral movement in one direction is possible by driving the trailer combination forwards and a slight lateral movement in the other, opposing direction is possible by reversing the trailer combination. This is time-consuming, the positioning options are fairly restricted and, moreover, require movement of the combination in the longitudinal direction.
The aim of the present invention is to overcome the abovementioned problems associated with the repositioning or fine positioning of the container with respect to the trailer, or at least appreciably to simplify the repositioning of the trailer with respect to the container. The abovementioned aim is achieved according to the invention in that the trailer further comprises transverse positioning means which are suitable for causing the trailer, in the coupled-up state, to rotate about the coupling axis of rotation of the coupling with the tractor, such that the rear end of the trailer is moved in the horizontal transverse direction of the trailer and specifically preferably when the towing vehicle is stationary. This can be achieved, for example, by providing one or more pairs of wheels of the trailer with turnable wheels, such that, in the transport position, said wheels can be brought into a position oriented in the longitudinal direction of the trailer and for repositioning can be moved into a position in which they are turned with respect to a vertical, in order to be able to move the trailer in the transverse direction while being driven via the wheels of the at least one pair of wheels turned into a transverse orientation. Although such a construction makes relatively easy repositioning possible, the mechanism required for bringing the wheels of the at least one pair of wheels into a repositioning position will be relatively complex and thus expensive.
According to an advantageous embodiment, the transverse positioning means for a trailer according to the invention will comprise: at least one transverse wheel which is oriented or can be oriented in the transverse direction of the trailer; and lifting means for lifting the at least one pair of wheels off the ground and bringing the at least one transverse wheel into contact with the ground. With this arrangement it is, for example, conceivable that the lifting means lift the pair of wheels or the pairs of wheels with which the trailer is bearing against the ground by, as it were, retracting said wheels with respect to the trailer, until the trailer bears against the ground via the at least one transverse wheel. A transverse wheel of this type is understood to be a wheel or roll-shaped revolving body, the axis of rotation of which extends in the longitudinal direction, optionally at a slight angle with respect thereto, of the trailer, optionally at an angle with respect to the horizontal plane, or a transverse wheel is understood to be a wheel or roll-shaped revolving body, the roll or driving direction of which essentially extends in the transverse direction of the trailer. It will be clear that one
or more transverse wheels can be concerned here. When the at least one transverse wheel has come into contact with the ground and the at least one pair of wheels has been lifted off the ground, the trailer can be moved in the transverse direction, during which operation said trailer will turn about the coupling axis of rotation, by pushing the trailer from the side or pulling the trailer from the side in the desired transverse direction. When the desired transverse displacement of the trailer has been achieved, the lifting means can return the transverse wheel and the at least one pair of wheels to the original position.
In order to facilitate the lateral displacement of the trailer for repositioning thereof with respect to the container, it is advantageous, according to the invention, if the one transverse wheel or, in the case of multiple transverse wheels, at least one of said transverse wheels, is drivable by means of drive means. With this arrangement, said drive means will preferably be provided on the trailer. Especially in the case of one drivable transverse wheel, said drive means will be suitable for making said transverse wheel rotate in the two opposing directions of rotation, that is to say clockwise and anticlockwise. In the case of two drivable transverse wheels it is optionally conceivable that the one transverse wheel is drivable in the one direction and the other transverse wheel in the other direction, in order to be able to adjust the trailer in the two transverse directions.
In order, inter alia, to make adjustment possible accurately and also over small lateral distances relatively easily, it is advantageous according to the invention if the at least one transverse wheel, viewed in the longitudinal direction of the trailer, is mounted between the rear end of the trailer and the rearmost pair of wheels. After all, a relatively small rotation of the transverse wheel will then result in a relatively small transverse displacement of the trailer. If the at least one transverse wheel, in particular the drivable transverse wheel, is placed closer to the front of the trailer, a relatively small rotation of said drivable transverse wheel will result in a relatively larger lateral displacement of the trailer. In this context, it is generally advantageous, from the standpoint of construction, if the at least one transverse wheel is mounted preferably between the pairs of wheels or, viewed in the longitudinal direction of the trailer, close behind these, such as, for example, approximately 100 cm or less behind these. This is because in general adjustments to the frame of the trailer are generally already necessary in the vicinity of the pairs of wheels in order to be able to house the pairs of wheels and the suspensions thereof.
So as to be able to leave the existing suspension/suspensions of the pairs of wheels unmodified, it will be advantageous according to the invention if the lifting means engage,
on the one hand, on the frame of the trailer and, on the other hand, on the at least one transverse wheel in order, on activation of the lifting means, to be able to move said transverse wheel downwards with respect to the frame until it comes into contact with the ground and to be able to push the frame upwards with respect to the ground until the at least one pair of wheels, in particular all existing pairs of wheels, comes or come off the ground. Following repositioning, the lifting means can lift the at least one transverse wheel again, so that one or more pairs of wheels of the trailer once again come into contact with the ground. In this context it will be clear that the closer said at least one transverse wheel is mounted to the rear of the trailer the smaller will be the power to be supplied by the lifting means to lift the pairs of wheels off the ground. After all, the distance between the transverse wheel and the tractor/the towing vehicle then increases.
In order to counteract sideways tilting of the trailer in the case of one transverse wheel or several transverse wheels mounted along a line extending in the longitudinal direction of the trailer, it is advantageous according to the invention if said one transverse wheel or said transverse wheels are mounted essentially symmetrically with respect to the longitudinal axis of the tractor, that is to say as far as possible in the middle of the trailer, viewed in the transverse direction. In the case of multiple transverse wheels which are not aligned in the longitudinal direction, it will be preferable if said transverse wheels are mounted symmetrically with respect to the longitudinal centre line of the tractor, in order that said transverse wheels are loaded as uniformly as possible when the trailer is raised and driven sideways.
Advantageously, the lifting means of the transverse positioning means will comprise one or more hydraulic cylinder/piston units.
According to an embodiment of simple construction, the at least one transverse wheel is attached to an arm, which at one end is hingably attached to the frame of the trailer and on which, preferably at the other end, the lifting means engage. Such an arm can extend either in the transverse direction of the trailer (as shown in the illustrative embodiments) or in the longitudinal direction of the trailer, the last-mentioned longitudinal orientation of the arm having the advantage that the point at which the transverse wheel comes into contact with the ground is fixed, at least viewed in the transverse direction of the trailer, and is thus independent of the degree to which the arm has to be rotated by the lifting means in order to lift the at least one pair of wheels off the ground.
According to another advantageous embodiment, the at least one transverse wheel will
be mounted on the trailer by means of a scissor mechanism operated by the lifting means By means of such a scissor mechanism it is relatively easy to implement a construction with which the at least one transverse wheel is movable up and down essentially vertically, at least without being subject to a displacement m the lateral direction of the trailer The transverse positioning means according to the invention can in particular be advantageously used with a trailer which is provided with a tilting mechanism that is suitable for making the trailer or a container support frame mounted thereon to tilt with respect to a hoπzontal tilt axis transversely to the longitudinal direction of the trailer, such that the rear end of the trailer, or the container frame, is moved towards the ground and optionally is brought into contact with the latter A tilting mechanism of this type is disclosed, for example, m EP-B1 0 723 505
The present invention will be explained in more detail below with reference to a number of diagrammatic figures In said figures
Figure 1 shows, highly diagrammatically, a detail of a rear view of a trailer according to the invention provided with transverse positioning means according to one embodiment,
Figure 2 shows a highly diagrammatic rear view of a detail of a trailer according to the invention provided with transverse positioning means according to another embodiment,
Figure 3 shows a highly diagrammatic side view of an assembly of a trailer according to the invention in combination with a tractor/towmg vehicle, in which a possible use of a trailer according to the invention is indicated diagrammatically,
Figure 4 shows, highly diagrammatically, a trailer according to the invention provided with a tilting mechanism by means of which the entire trailer frame is tiltable until the rear thereof comes into contact with the ground,
Figure 5 shows a trailer according to the invention provided with a container frame which is tiltable with respect to the trailer frame
Figure 1 shows, highly diagrammatically, a rear view of the rearmost pair of wheels, consisting of a right wheel 1 and left wheel 2, of a trailer, of which only the trailer frame 3, on which the wheels 1 and 2 are mounted, is shown An arm 5 is mounted on the trailer frame 3 by means of a hmged fixing 4, which arm is swivelable with respect to the trailer frame 3 by means of lifting means 6 In this embodiment the lifting means 6 consist of a cylinder/piston assembly which can be retracted and extended by means of a hydraulic fluid By extending the cylinder/piston assembly 6 with the aid of the hydraulic fluid, a transverse wheel 7 mounted on the arm 5 is brought into contact with the ground 8 By
further extending the hydraulic cylinder/piston assembly 6, the wheels 1 and 2 then come off the ground. By now rotating the transverse wheel 7 in the clockwise direction by means of drive means 9 provided for this purpose, the trailer frame 3 is moved to the right in the direction of the arrow R, and by rotating the wheel 7 anticlockwise by means of the drive means 9 the trailer frame 3 is moved to the left in the direction of the arrow L. During said displacement of the trailer frame 3 to the right or the left, respectively, the trailer frame 3 is actually swung about a axis of rotation 100 which runs essentially vertically through the coupling of the trailer to the towing vehicle. It will be clear that by turning the transverse wheel 7 a greater or lesser extent in the one or the other direction in this way, the trailer frame 3, or at least the rear end thereof, from which a container has to be pulled up onto the trailer, can be displaced/swung to the left or the right to a greater or lesser extent in order better to position the trailer frame with respect to the container to be placed thereon. In the embodiment according to Figure 1, the so-called transverse positioning means 10 thus essentially consist of the lifting means 6, the arm 5 hingably mounted on the trailer frame 3 and the transverse wheel 7 plus, optionally, the drive 9.
In the illustrative embodiment shown in Figure 1 the arm 5 is rotatable in a plane essentially transverse to the longitudinal direction of the trailer 3. However, it is will be clear that the arm 5 can also be mounted such that it is swivelable in a plane essentially vertical and parallel to the longitudinal direction of the trailer 3. This has the advantage that the lateral distance of the transverse wheel 7 from, on the one hand, the right wheel 1 and, on the other hand, the left wheel 2 remains unchanged on swivelling the arm 5. As an example of such a construction, reference can be made, for example, to Figure 4 of EP-B 0 723 505, where, however, the roller 20 is not oriented in the so-called transverse direction and thus does not form a so-called transverse wheel. Figure 2 shows a modified embodiment of the transverse positioning means, which in this figure are indicated by the numeral 20. The transverse positioning means 20 of the embodiment in Figure 2 comprise a support arm 15 on which the transverse wheel 7 is mounted. The support arm 15 is mounted by means of a scissor mechanism on the trailer frame 3. Said scissor mechanism consists of two telescopic arms 16 and 17 arranged crosswise. With this arrangement said telescopic arms 16 and 17 can each be constructed as a cylinder/piston unit that can be operated by means of hydraulic fluid. In this context it will be clear that by activating each of the cylinder/piston units 16 and 17 with hydraulic fluid such that said units extend, the support arm 15, with the transverse wheel 7 attached
thereto, will be moved downwards. If said extension of the cylinder/piston units 16 and 17 takes place to an adequate extent, the transverse wheel 7 will first come into contact with the ground 8 and then lift the wheels 1 and 2 off the ground. After the wheels 1 and 2 have been lifted off the ground, the trailer can be moved to the right R or left L by rotating the transverse wheel 7 by means of the drive means 9 in the relevant suitable direction.
It will be clear that when the trailer has been positioned in the transverse direction by means of the so-called transverse positioning means, such as the transverse positioning means 10 or 20, the lifting means will be activated in the opposite direction in order to bring the at least one pair of wheels back towards the ground and into contact with the ground and then to lift the at least one transverse wheel off the ground again. With regard to the illustrative embodiments shown in Figures 1 and 2, this means that the cylinder/piston units 6 and, respectively, 16 and 17, are retracted again.
In Figures 3, 4 and 5, which will be discussed below, the transverse positioning means are always indicated by 30. It will be clear that in the case of the applications described in Figures 3, 4 and 5 the transverse positioning means 30 can comprise either transverse positioning means 10 or transverse positioning means 20, as well as other embodiments of transverse positioning means. The transverse positioning means 30 comprise one or more so-called transverse wheels 7, which, by means of lifting means, are movable up and down with respect to the trailer 3 in the vertical direction, oblique vertical direction or in accordance with an arc of a circle. When the transverse wheels 7 are moved down by means of the lifting means and come into contact with the ground 8, the trailer frame will bear on the transverse wheels 7 at the back and on the tractor 34 at the front. By forcing the transverse wheels 7, by means of the lifting means, further downwards with respect to the trailer frame 3, the pairs of wheels 31 and 32 will then come off the ground. By operating the drive 9, it will then be possible to displace the trailer frame 3 in the transverse direction thereof, that is to say perpendicular to the plane of the drawing in Figures 3, 4 and 5, that is to say to swivel said trailer frame 3 about coupling axis of rotation 100.
In Figures 3, 4 and 5 the trailer 3 is further provided with a winch 35 with hauling line 36. By attaching the hauling line 36 to a container 38 at 37, the container 38 can be pulled onto the trailer in the longitudinal direction of the trailer. Winch and hauling line mechanisms of this type are known per se from the prior art in diverse embodiments; see, for example, EP-B1 0 723 505 and the further prior art cited therein.
Figure 3 shows diagrammatically that a trailer according to the invention can be displaced in a direction perpendicular to the plane of the drawing in order to bring said trailer better in line with a container 38 which is placed on a raised platform 39 and has to be loaded on the trailer. In the embodiment according to Figure 4 a trailer 3 is concerned which on coupling up with the tractor 34 can be tilted as a whole by means of a tilting mechanism 40, such that the rear end 41 of the trailer 3 is brought very close to the ground or into contact with the ground 8, whilst the trailer 3 then rests on the rearmost pair of wheels 31. The pair of wheels 32 has then been lifted off the ground. If the trailer frame 3 now has to be adjusted in a direction transverse to the plane of the drawing in Figure 4, the transverse positioning means 30 can then be used for this purpose. By means of the transverse positioning means 30, the rearmost pair of wheels 31 is then lifted off the ground and the rear end 41 of the trailer 3 is movable in the sideways direction, that is to say in a direction perpendicular to the plane of the drawing, by making the trailer 3 rotate about axis of rotation 100 through a generally small to very small angle by rotating the transverse wheels 7 to a sufficient extent by means of the drive 9.
Figure 5 shows an embodiment which is similar to that according to Figure 4, except that the trailer frame 3 in this case is provided with an additional container frame 51. When loading and unloading containers 38, said container frame 51 can be tilted by means of a tilting mechanism 50 and 52 such that the rear end 53 thereof comes into contact with the ground 8. With this arrangement the tilting mechanism consists of a cylinder/piston unit 50 and a horizontal tilt shaft 52, via which the container frame 51 and the trailer frame 3 are connected to one another.
When the container 30 has been loaded onto the trailer in the embodiments according to Figures 4 and 5, the trailer frame 3 or, respectively, the container frame 51 will be brought back into the horizontal position. This is generally known per se from the prior art in a multiplicity of embodiments. With regard to such tilting mechanisms reference can be made, for example, to EP-B 0 723 505 and the further prior art cited therein.
It will be clear that a trailer provided with transverse positioning means according to the invention can also be highly advantageous if a container has to be unloaded from the trailer. In this case as well it is then possible, at least provided that the lifting means are able to supply sufficient power for this purpose, to lift the trailer off the ground and to swivel it about axis of rotation 100, such that the rear end of the trailer is displaced in the
lateral direction. Especially in the case of longer trailers, such as those for so-called 40-foot containers, the trailer will approximately move sideways as a whole with relatively small swivel angles.
For stability considerations it could be advantageous to use two (or more) so-called transverse wheels which are mounted symmetrically with respect to the mid longitudinal axis of the trailer. Furthermore, it will be clear that the driving direction of the so-called transverse wheels preferably extends essentially transversely to the longitudinal direction of the trailer, in particular such that the driving direction runs tangentially with respect to the coupling axis of rotation 100. However, it will be clear to an average person skilled in the art that the driving direction can also deviate from this to some extent without any great problems. Furthermore, the revolving surfaces of the transverse wheels can run at an angle with respect to the vertical.
A major advantage of the invention is, furthermore, that the operation of the transverse positioning mechanism can take place at the rear end of the trailer, such as optionally at the location of the pairs of wheels, so that the operator is immediately able to detect visually whether the trailer still requires further repositioning or is in the correct position with respect to the container. Operation of this type at the rear end of the trailer or at the location of the pairs of wheels can be achieved by providing a suitable control panel at this location, optionally supplemented by a remote control connected by a cable. It will be clear that in the case of a trailer having a subframe with sets of wheels intended for normal transport, which subframe is movable in the longitudinal direction thereof, the transverse positioning means can be mounted either on said movable subframe or on the trailer frame itself.