GB2436712A

GB2436712A - Industrial tractor for the transportation of mobile containers.

Info

Publication number: GB2436712A
Application number: GB0705701A
Authority: GB
Inventors: Jean-Marie Martin
Original assignee: Linde Material Handling GmbH; Linde Material Handling GmbH and Co KG
Current assignee: Linde Material Handling GmbH; Linde Material Handling GmbH and Co KG
Priority date: 2006-03-28
Filing date: 2007-03-26
Publication date: 2007-10-03
Anticipated expiration: 2027-03-26
Also published as: GB0705701D0; DE102006014338B4; FR2899196B1; DE102006014338A1; GB2436712B; FR2899196A1

Abstract

The subject of the invention is an industrial tractor for the transportation of mobile transport containers (12), in particular roll containers or box pallets. The industrial tractor has a steerable drive wheel (3) and at least two non-driven wheels (6, 7). The industrial tractor also has a coupling device (8) for coupling a mobile transport container (12) to the industrial tractor. According to the invention, at least two non-pivotable wheels (6) and at least two pivotable wheels (7) are provided as non-driven wheels (6, 7), the non-pivotable wheels (6) and the pivotable wheels (7) being adjustable relative to one another in the vertical direction.

Description

O i 243672 Industrial liactor for the transportation of mobile

transport containers The invent ion relates to an industrial tractor for the transportation of mobile transport containers, in particular roil containers or box pallets, wherein the industrial tractor has a steerable drive wheel and at least two non-driven wheels and wherein the industrial tractor has a coupling device for coupling a mobile transport container to the industrial tractor.

Industrial tractors of said type are especially designed for the transportation of mobile transport containers, such as are used, in particular, in the retail food trade and wholesale food trade. These transport containers generally have four wheels, a base plate and at least two side grid walls which project upwardly from the base plate. Two pivot rollers and two non-pivotable wheels are generally provided as wheels, It is also known to equip transport containers of this type with four pivot rollers. The goods to be transported are stacked on top of one another to a height of about 2 meters on the base plate between the side grid walls.

The mobile transport containers are frequently pushed manually by warehouse workers. However, there is a risk here of the transport container tipping over, above all in the case of goods which are heavy and piled up high.

This risk is particularly great during the manual pushing or pulling of the transport containers because the force introduction point is located at the level of the hands of the warehouse worker and therefore at the top of the transport container.

Known industrial tractors are only suitable to a limited degree tor the transportation of the above-described transport containers. These industrial tractors are frequently derived from drawbar-steered lifting trucks and have a drive wheel which can be steered by means of a steering drawbar and two wheels, which are not driven, cannot be steered and are not pivotable. The coupling device in known industrial tractors is designed similarly to a coupling known from the lorry or passenger car sector and allows a rotary movement of the transport container relative to the industrial tractor in all directions. This is necessary in known industrial tractors in order to produce the steerability of the system consisting of the industrial tractor and transport container. For example, with a laterally inclined road or when the transport container is pushed, there is a risk, however, of a lateral bending of the transport container relative to the industrial tractor.

The present invention is therefore based on the object of providing an industrial tractor which is better suited for pulling and pushing mobile transport containers.

This object is achieved according to the invention in that at least two non-pivot able wheels and at least two pivotable wheels are provided as non-driven wheels, the non-pivotable wheels and the pivotable wheels being adjustable relative to one another in the vertical direction. The pivotable wheels are pivot rollers, which can be freely pivoted relative to a frame of the industrial tractor about a vertical axis. As a function of the respective operating situation it can be selected whether the non-pivotable wheels are raised relative to the pivofable wheels or are lowered to the level of the pivotable wheels.

It is expedient here if the non-driven wheels can be adjusted relative to one another in such a way that the non-pivotable wheels are optionally in contact with a road or are raised from the road. If the non-pivofable wheels are raised from the road, the industrial tractor, in the region of the non-driven wheels, stands exclusively with the pivotable wheels on the road and has no lateral guidance there. If the non- pivotable wheels are lowered onto the road, the pivotable wheels can also stand on the road at the same time. The industrial tractor is then guided by the non-pivotable wheels in the lateral direction on the road.

I

According to an expedient development of the invention, the coupling device is designed in such a way that a transport container coupled to the industrial tractor is fixed with respect to a rotation about a vertical axis relative to the industrial tractor. This means that a rotation of the transport container about a vertical axis is only possible together with the industrial tractor. A bending away of the transport container in the coasting mode of the industrial tractor or with a laterally inclined road is thus reliably avoided.

Driving onto ramps with an upwardly or downwardly inclined road is made possible in that the coupling device is designed in such a way that a transport container coupled to the industrial tractor can be pivoted about a horizontal transverse axis of the industrial tractor relative to the industrial tractor.

The coupling device expediently has an open and a closed operating position and the coupling device is in operative connection with the non-driven wheels in such a way that when the coupling device is open, the non-pivofable wheels are in contact with the road and, when the coupling device is closed, the pivot able wheels are in contact with the road and the non-pivotable wheels are raised relative to the road. When the coupling device is open, no transport container is connected to the industrial tractor. To couple a transport container, the industrial tractor is driven into the corresponding position of the industrial tractor with the coupling device open and the coupling device is then closed.

The transport container is then rigidly connected to the tractor, with the coupling device closed, until the coupling device is opened again. When the coupling device is closed, fhe industrial tractor always stands only with the pivofable wheels and the drive wheel on the road. This is expedient when the transport container has two pivotable wheels and two non-pivotable wheels.

The system of industrial tractor and transport container then has a steerable drive wheel on the industrial tractor and two non-pivotable wheels on the transport container. This ensures the required driving and directional stability of the system. The remaining wheels of the system, in other words the two further wheels of the transport container and the Iwo non-driven wheels of the industrial tractor standing on the road are pivofable. This ensures the sfeerabilify of the system. As the non-pivotable wheels of the tractor are raised, none of the wheels are dragged over the road transverse to the rolling direction during steering.

According to an expedient embodiment of the invention, the pivotable wheels of the industrial tractor are fixed to a frame of the industrial tractor and the non-pivotable wheels can be moved relative to a frame of the industrial tractor in the vertical direction.

To adjust the non-pivotable wheels relative to the frame of the industrial tractor, a pneumatic actuator is provided.

To steer the steerable wheel of the industrial tractor, a steering drawbar is provided. The required steering force is thus generated manually. In the region of a handle of the steering drawbar, operating elements are arranged, for example for the traction drive and to switch over the coupling device between the open and closed position. With this operating element for the coupling device, the actuator to adjust the non-pivotable wheels of the industrial tractor is activated at the same time.

The subject of the invention is also a transport system with an industrial tractor of the above-described type and a mobile transport container. As already mentioned, the transport container has two pivotable wheels and Iwo non-pivot able wheels.

Further advantages and details of the invention will be described in more detail with the aid of the embodiment shown in the schematic figures, in which Figure 1 shows a lateral view of an industrial tractor according to the invention; Figure 2 shows the industrial tractor in a view from below;

I

( Figure 3 shows a plan view of an industrial tractor with a coupled transport container: Figure 4 shows a non-pivotable wheel in the raised position; and Figure 5 shows the non-pivotable wheel in the lowered position.

Figure 1 shows an industrial tractor according to the invention in a side view. A frame 1 of the industrial tractor, on which a drive unit 2 with a drive wheel 3 is mounted in a steerable manner, can be seen. The required steering force is exerted on the drive unit 2 by an operator by means of a drawbar 4.

Located at the end of the industrial tractor opposing the drive unit 2 is a total of four non-driven wheels. These are two wheels 6 which cannot be pivoted relative to the frame 1 and two wheels 7 pivotably mounted on the frame 1, which are designed as pivot rollers. Mounted on the load end of the industrial tractor is a coupling device 8. which comprises a hook 9 which can be moved in the vertical direction. A horizontal strut of a mobile transport container can be hooked into from below with the hook 9. The coupling device 8 also comprises a safety element 10, which prevents the horizontal strut of the transport container from jumping up out of the hook 9. The safety element 10 is configured as an inflatable airbag, which, in the inflated state, arches to the right in the drawing over the hook 9. The various units of the industrial tractor, for example electric drive batteries, an electrically driven compressor and a power electronics unit to supply the compressor and the drive unit 2 are located under a housing 11.

Depending on the operating situation of the industrial tractor, in particular depending on whether a transport container 12 is coupled to the industrial tractor, the non-pivotable wheels 6 are raised or are in contact with the road.

For this purpose, the non-pivofable wheels 6 are height-adjustably mounted on the frame 1. When the hook 9 is lowered and therefore the coupling device 8 is open, the non-pivotable wheels 6 are lowered, If, on the other hand, the hook 9 4 I is raised and therefore the coupling device 8 is closed, the non-pivofable wheels 6 are raised. The pivotable wheels 7 arranged on the outside are in contact with the road in every situation. When, with the coupling device 8 closed, both the pivotable wheels 7 and the non-pivotable wheels 6 are in contact with the road, the non-pivotable wheels 6 are used for track guidance of the industrial tractor and the pivotable wheels 7 prevent lateral tipping over of the indusfrial tractor.

Figure 2 shows the industrial tractor according to Figure 1 from below. In particular, the height-adjustable, non-pivotable wheels 6 arranged on the inside and the pivotable wheels 7 arranged on the outside can be seen here.

Figure 3 shows a plan view of an industrial tractor with a coupled transport container 12. The industrial tractor and the transport container 12 together form a transport system. The transport container 12 is rigidly coupled to the industrial tractor. The coupling device 8, in particular, prevents a rotation of the transport container 12 relative to the industrial tractor about an axis which is perpendicular to the plane of the drawing. When the transport container 12 is coupled, the industrial tractor stands with the pivotable wheels 7 on the road.

The turning radius of the transport system is then determined by the arrangement of the wheels on the transport container 12. When the wheels 13 adjacent to the industrial tractor are not pivotable and the wheels 14 spaced apart from the industrial tractor are pivotable, the turning radius Ri is produced.

In contrast, the turning radius R2 is produced when the wheels 13 of the transport container 12 adjacent to the industrial tractor are pivotable and the wheels 14 spaced apart from the industrial tractor are not pivotable.

If a transport container is used, which exclusively has pivotable wheels 13, 14, the non-pivotable wheels 6 of the industrial tractor must be constantly in contact with the road, regardless of whether the transport container is coupled or uncoupled. The turning radius of the system of industrial tractor and transport container 12 is then identical to the turning radius of the industrial tractor itself.

( The mechanism for height adjustment of the non-pivofable wheels 6 is shown in Figures 4 and 5. The wheels 6 are rotatably mounted on a lever 16. The lever 16 is in turn mounted on a fork 17 so as to be pivotable about an axle 19, which is rigidly connected to the frame 1. Located between the frame 1 and the upper part of the lever 16 is a pneumatic actuator 18, which in the present embodiment is formed by a flexible, inflatable airbag. Furthermore, a spring 19 generating a restoring force is arranged between the frame 1 and the lower part of the lever 16. The restoring force counteracts the force of the pneumatic actuator 18.

In the position shown in Figure 4, the pneumatic cylinder 18 is extended, so the lever 16 is pivoted about the axle 19 in the clockwise direction and the spring 18 is compressed. The wheel 6 is thereby raised from the road 20. If the air is now let out of the cylinder 18, the spring 18 pivots the lever 16 in the anti-clockwise direction back into the position shown in Figure 5. The wheel 6 thus comes into contact with the road 20.

Claims

( Claims 1. An industrial tractor for the transportation of mobile

transport containers, in particular roll containers or box pallets, wherein the industrial tractor has a steerable drive wheel and at least two non-driven wheels and wherein the industrial tractor has a coupling device (8) for coupling a mobile transport container to the industrial tractor, characterised in that at least Iwo non-pivofable wheels and at least two pivotable wheels are provided as non-driven wheels, the non-pivotable wheels and the pivotable wheels being adjustable relative to one another in the vertical direction.

2. An industrial tractor according to claim 1, characferised in that the non- driven wheels are adjustable relative to one another in such a way that the non-pivotable wheels are optionally in contact with a road or are raised from the road.

3. An industrial tractor according to claim 1 or 2, characterised in that the coupling device is designed in such a way that a transport container coupled to the industrial tractor is fixed with respect to a rotation about a vertical axis relative to the industrial tractor.

4. An industrial tractor according to any one of claims 1 to 3, characterjsed in that the coupling device is designed in such a way that a transport container coupled to the industrial tractor can be pivoted about a horizontal transverse axis of the industrial tractor relative to the industrial tractor.

5. An industrial tractor according to any one of claims 1 to 4, characferised in that the coupling device has an open and a closed operating position and the coupling device is in operative connection with the non-driven wheels in such a way that when the coupling device (8) is open, the non-pivotable wheels are in contact with the road and, when the coupling device is closed, the pivotable wheels are in contact with the road and the non-pivotable wheels are raised relative to the road.

6. An industrial tractor according to any one of claims 1 to 5, characterised in that the pivotable wheels are fixed to a frame of the industrial tractor and f he non-pivotable wheels can be moved relative to a frame of the industrial tractor in the vertical direction.

7. An industrial tractor according to any one of claims 1 to 6, characterised in that a pneumatic actuator is provided to adjust the non-pivot able wheels relative to the frame of the industrial tractor.

8. An industrial tractor according to any one of claims I to 7, charocferised in that a steering drawbar is provided to steer the steerable wheel of the industrial tractor.

9. Transport system with an industrial tractor according to any one of claims I to 8 and a mobile transport container, characterised in that the transport container has two non-pivofable wheels and two pivotable wheels.