GB2468937A

GB2468937A - Industrial truck comprising a platform-central part

Info

Publication number: GB2468937A
Application number: GB0920179A
Authority: GB
Inventors: Christoph Hackbarth
Original assignee: Jungheinrich AG
Current assignee: Jungheinrich AG
Priority date: 2009-03-26
Filing date: 2009-11-18
Publication date: 2010-09-29
Anticipated expiration: 2029-11-18
Also published as: DE102009014391B4; GB0920179D0; GB2468937B; DE102009014391A1

Abstract

There is provided an industrial truck comprising a drive part 10 which has at least one drive wheel 12, a load-bearing part 14 which is configured for receiving a load to be transported, and a central part 18 arranged between the drive part and the load-bearing part which has a platform 20 on which a driver of the industrial truck may ride and the arrangement thereof determining the ground clearance of the industrial truck in the region of the central part, the load-bearing part being height-adjustable relative to the central part for lifting a load (figure 3), characterized in that the central part is height-adjustable relative to the drive part (figure 4). Height adjustable rollers 32 may be arranged on a pivot arm (36) on the load-bearing part, said part being displaceable in parallel relative to the central part by means of guide 24. The central part and the drive part may be connected via a height adjustable pivot pin and at least one arm.

Description

Industrial truck comprising a platform-central part The invention relates to an industrial truck according to the preamble of Claim 1. It comprises a drive part which has at least one drive wheel, a load-bearing part which is configured for receiving a load to be transported, and a central part arranged between the drive part and the load-bearing part which has a platform on which a driver of the industrial truck may ride and the arrangement thereof determining the ground clearance of the industrial truck in the region of the central part, the load-bearing part being height-adjustable relative to the central part for lifting a load. Such industrial trucks are frequently denoted as order picker vehicles. The particular advantage thereof is in the compact construction and the possibility of a driver riding thereon. Said driver may preferably ride by standing on the platform, a low overall height of the platform being desired in order to facilitate frequent boarding and dismounting.

A known industrial truck of this design has a central part which comprises a steel frame connected fixedly to the drive part. The lower surfaces of the steel frame determine the ground clearance of the known industrial truck in the region of the central part. In a specific design of the industrial truck, the platform is not fixedly connected to the frame for the driver but designed to be height-adjustable relative to the frame. As a result, the driver may move upwards on the platform in order, for example, to reach a shelf located higher up. The height adjustment of the load-bearing part takes place in the known industrial truck relative to the central part which is fixedly connected to the drive part. In order to lift a load, the load-bearing part may be moved upwards parallel to the central part. The vertical position of the central part and drive part remains, therefore, unaltered. The ground clearance in the region of the central part may, therefore, not be influenced in the known industrial truck.

Other known industrial trucks which, however, do not have a central part with a platform, but substantially consist only of a drive part and a load-bearing part, may as a result be adapted to inclined ground, by the end of the load-bearing part remote from the drive part, in particular the tines of a load-bearing fork, being height-adjustable independently of the end of the load-bearing part facing the drive part.

Such an industrial truck is known from DE 36 14 986 Al. It has a tiller-guided drive part with a drive wheel and a load-bearing part displaceably guided in parallel vertically thereto. A lifting cylinder is connected to the drive part and may lift the load-bearing part relative to the drive part. The load-bearing part has a load-bearing fork, at the ends thereof remote from the drive part one respective roller is arranged. The roller is fastened to a pivot arm pivotably mounted relative to the load-bearing part. The pivoting movement of the pivot arm is coupled via a rod assembly and a deflection lever with the movement of the load-bearing part relative to the drive part. In normal operation on horizontal ground, the load-bearing part is lifted and/or lowered at both ends equally via this coupling, so that it always remains in substantially horizontal alignment. Via a separate lifting cylinder in the drive part, a deflection lever of the disclosed coupling mechanism may be adjusted such that the pivot arm may be positioned irrespective of the adjusting movement of the load-bearing part relative to the drive part. As a result, a lowering of the fork tines is possible, in particular when the load-bearing fork is intended to be moved underneath a load located at the upper end of a ramp.

A further industrial truck without the possibility of riding thereon is known from DE 41 36 820 Cl. Said industrial truck also has a tiller-guided drive part and a load-bearing part in the form of a load-bearing fork with rollers arranged on pivot arms. For the parallel, vertical adjustment of the load-bearing fork, a lifting cylinder is used, which is fastened to an intermediate frame arranged vertically. It lifts the load-bearing part relative to the intermediate frame, said relative movement being transmitted via a rod assembly and a deflection lever to the pivot arm with the roller, in a similar manner as in the above-described solution. A further lifting cylinder is connected to the side of the vertical intermediate frame remote from the load-bearing part. It acts on the drive part and may lift the intermediate frame relative to the drive part. The movement of this second lifting cylinder has no influence on the position of the pivot arm with the roller.

Instead, exclusively the intermediate frame and thereby the end of the load-bearing part facing the drive part are vertically displaced. Also, this known industrial truck is intended, in particular, to permit receiving a load in the region of a ramp.

Proceeding therefrom, it is the object of the invention to provide an industrial truck according to the preamble of Claim 1, which may be used in a versatile manner on uneven and/or inclined ground.

I

This object is achieved by the industrial truck comprising the features of Claim 1. The industrial truck has a drive part which has a drive wheel, a load-bearing part which is configured for receiving a load to be transported, and a central part arranged between the drive part and the load-bearing part which has a platform on which a driver of the industrial truck may ride and the arrangement thereof determining the ground clearance of the industrial truck in the region of the central part, the load-bearing part being height-adjustable relative to the central part for lifting a load and the central part being height-adjustable relative to the drive part.

The invention is based on the recognition that, with the aforementioned industrial truck according to the preamble of Claim 1, specific problems may occur with uneven ground, due to the low ground clearance in the region of the central part. The low ground clearance is, therefore, a necessary consequence of the desired low height of the platform. It is not provided, therefore, to arrange the entire central part higher for the purpose of increasing the ground clearance. The solutions known from the prior art for adapting to inclined ground may not be transferred to industrial trucks with a central part. The lowering of the load-bearing part at its end remote from the drive part would in this case lead to ground contact in the region of the central part, due to the unavoidable incline of the drive part and central part.

According to the invention it is, therefore, proposed to provide additional height adjustability of the central part relative to the drive part. As a result, the central part may be displaced upwards relative to the drive part, so that the ground clearance below the central part is correspondingly increased. The height of the platform is thus also increased which, however, only compromises the desired low boarding height when the industrial truck is actually operated in the region of a ramp or particularly uneven ground. In normal operation, the central part may remain in its lower position relative to the drive part, so that the height of the platform remains in the region which is

customary from the prior art.

Additionally to the drive wheel, the drive part may comprise one or more support wheels. The drive wheel may, in particular, be driven by an electric motor.

Preferably, the drive wheel is steerable. The load-bearing part may, in particular, have a load-bearing fork. It may comprise rollers or wheels, which are connected via pivot arms to the load-bearing part.

The platform of the central part may, in particular, be a standing platform. It is conceivable, however, also to provide a driver seat on the platform. The platform may additionally, as known from the prior art, be designed to be height-adjustable relative to the central part. The central part may further comprise a backrest and one or more grip handles, which permit the driver a more secure and comfortable standing position.

By means of the invention, the ground clearance in the region of the central part may be increased in a specific manner so that ground contact, in particular in the region of the upper end of a ramp, may be reliably avoided. At the same time, by means of the height adjustability of the central part relative to the drive part, the load-bearing part may be inclined in a specific manner, so that its alignment deviates from the horizontal.

In a preferred embodiment, an actuating device for the drive and/or the steering of the drive wheel is fastened to the central part. In principle, such an actuating device may also be fastened to the drive part, as known from the prior art. The aforementioned design, however, provides the particular advantage that the actuating device always remains at an ergonomic level irrespective of the vertical adjustment of the central part relative to the drive part.

According to one embodiment, the central part has a guide which guides the load-bearing part, so that it is displaceable in parallel relative to the central part. The guide may, for example, have U-shaped, vertically-arranged profiles, in which one or more wheels or rollers are guided. The load-bearing part may, in particular, comprise a carriage which is connected to said rollers or wheels. Such a guide permits a vertical adjustment of the load-bearing part, in which a preferred horizontal alignment both of the load-bearing part and also of the central part is maintained.

According to one embodiment, a lifting cylinder is present which is connected to the central part and to the load-bearing part, so that it may adjust the vertical position of the load-bearing part relative to the central part. Preferably, the lifting cylinder is fastened to the central part and a piston rod of the lifting cylinder is connected to the load-bearing part. In this manner, a robust and reliable height adjustment is possible.

In one embodiment, on the load-bearing part height-adjustable rollers are arranged on a pivot arm, the pivoting movement thereof being able to be coupled to the height adjusting movement of the load-bearing part relative to the central part. The coupling may, for example, take place by means of a rod and one or more deflection levers. It is then a mechanical coupling. Alternatively, the pivot arm may have a separate drive device, for example in the form of a further lifting cylinder, which is coupled in terms of control engineering to the lifting cylinder connected to the central part. In both cases, a parallel lifting of the load-bearing part may be achieved by maintaining the horizontal alignment of a load-bearing means, such as for example a load-bearing fork.

In one embodiment, a lifting cylinder is present which is connected to the central part and to the drive part, so that it may adjust the vertical position of the central part relative to the drive part. Preferably, the lifting cylinder is fastened to the drive part, and a piston of the lifting cylinder is fastened to the central part. In this manner, a robust and reliable vertical adjustment is achieved.

According to one embodiment, the central part and the drive part are connected to one another via a height-adjustable pivot pin and via at least one arm spaced apart from the pivot pin, the one end thereof being pivotably fastened to the drive part and the other end thereof being pivotably fastened to the central part. In principle, between the central part and the drive part a guide may also be provided, which displaceably guides the central part in parallel relative to the drive part. The aforementioned embodiment does not lead to a parallel movement, but to a linear adjusting movement, which is superimposed by a pivoting movement, but is structurally less complicated. Due to the geometric relations provided, the pivoting component of the adjusting movement substantially leads to a slight incline of the drive part relative to the central part and load-bearing part. In practice, this inclined movement is of less importance.

In a preferred embodiment, a control unit is present by which the lifting cylinder connected to the central part and to the drive part may be controlled independently of the lifting cylinder connected to the central part and to the load-bearing part. As a result, in particular the angle of inclination of the load-bearing part may be set in a specific manner and, for example, adapted to an incline of the ground.

In one embodiment, the platform of the central part has a standing surface, which is arranged less than 200 mm high above the ground when the central part is fully lowered relative to the drive part, and the industrial truck in the region of the central part has a ground clearance of more than 40 mm, when the central part is fully raised relative to the drive part. Preferably, the height of the standing surface in the aforementioned state is less than 150 mm and the ground clearance in the aforementioned state is more than 75 mm. The aforementioned values ensure ground clearance which is well adapted to practical requirements, providing at the same time a more comfortable operating height of the standing surface.

The invention is described in more detail hereinafter with reference to an embodiment shown in five figures, in which: Figure 1 shows an industrial truck according to the invention with the load-bearing part and drive part lowered in a view from the side; Figure 2 shows the industrial truck from Figure 1 in a view from above; Figure 3 shows the industrial truck from Figure 1 with the load-bearing part raised and the central part lowered in a side view; Figure 4 shows the industrial truck of Figure 1 with the raised load-bearing part and central part in a side view; Figure 5 shows the industrial truck of Figure 1 in a perspective view with the cover partially removed.

The industrial truck shown in Figure 1 has a drive part 10 with an electrically driven drive wheel 12. A drive motor for the drive wheel 12 is accommodated in the drive part 10. The drive wheel 12 is additionally steerable.

The load-bearing part 14 in Figure 1 comprises a carriage, which is not visible, and two load-bearing forks 16 fastened thereto.

The central part 18 is located between the drive part 10 and the load-bearing part 14. The central part 18 has a platform 20 on which a driver may stand, as shown in the figure. A rear portion of the central part 18 extends upwards approximately as far as level with the hips of the driver and has a backrest 22, against which the driver may lean, if required. Moreover, within this portion of the central part 18 a guide 24 is located in which the carriage, not shown in the Figure 1, is displaceably guided in parallel. A lifting cylinder, also not visible in Figure 1, is used for adjustment.

A front portion 26 of the central part 18 is located in the direction of travel in front of the platform 20. In this portion, in particular, batteries for the power supply of the drive motor and a hydraulic pump are arranged. Also, to the central part 18 is fastened an actuating device in the form of a multifunction steering wheel 30, which is connected via a column 28 to a plate arranged substantially vertically, terminating the central part 18 at the front. Via the multifunction steering wheel 30 the steering and driving of the drive wheel 12 as well as at least one lifting cylinder may be controlled.

A further lifting cylinder is connected to the drive part 10 and the central part 18 by which the central part 18 may be lifted relative to the drive part 10. In this connection, the central part carries out a superimposed linear and pivoting movement relative to the drive part. A height-adjustable pivot pin is present, about which the common pivoting movement takes place, and an arm not shown in the figures, the one end thereof being pivotably connected to the central part 18 and the other end thereof being pivotably connected to the drive part 10, the arm being arranged at a distance from the common pivot pin and below said pivot pin.

Within and/or below the arms of the load-bearing fork 16 two respective rollers 32 are visible, which are connected via a pivot arm 36 (see Figures 3 and 4) to the load-bearing fork.

In the view of Figure 1, the central part 18 is in a lower position relative to the drive part 10, as is the load-bearing part 14 relative to the central part 18. In this position, the ground clearance below the central part 18 is relatively low. The ground clearance is, for example, a few centimetres. This leads to a lower height of the platform 20, which permits comfortable boarding. In this position, the platform 20 is at a height of approximately 135 mm above the flat ground indicated by 34.

In the view of Figure 2, substantially the same elements are again visible from above. Particularly clear is the parallel arrangement of the two arms of the load-bearing fork 16 with two respective rollers 32. The components, which are also visible, have already been described in connection with Figure 1, and provided in Figure 2 with the same reference numerals as in the other figures.

In Figure 3 a maximum lifted position of the load-bearing part 14 relative to the central part 18 is shown. In this position, the pivot arm 36 is pivoted downwards with the rollers 32 relative to the load-bearing fork 16. The arrangement of the central part 18 relative to the drive part 10 and the ground 34 is unaltered relative to Figure 1. The movement of the pivot arm 36 is coupled via a mechanical coupling mechanism, not shown in the figures, to the adjusting movement between the load-bearing part 14 and the central part 18.

In the view of Figure 4, additionally the central part 18 is in a raised position relative to the drive part 10. The load-bearing part 14 is further raised relative to the central part 18, as also shown in Figure 3. In this position, both the load-bearing part 14 and the central part 18 and the drive part 10 are slightly inclined relative to the ground 34. As may be seen immediately, the ground clearance is markedly increased in the region of the central part 18. At the rear end of the central part 18 where it is at its lowest, in the example shown, the ground clearance is 95 mm.

Parts of the two arms of the load-bearing fork 16 and the carriage 38 connected fixedly thereto are visible in Figure 5. The carriage 38 consists of two cross members 40, which are fixedly connected to one another via two vertically arranged profiles 42.

At the two sides of the cross members 40, further vertically arranged supports 44 are located which are guided via rollers in the guide profiles 24 of the central part 18. The lifting cylinder 46 is connected to the central part 18 and via its piston to the upper cross member 40 of the carriage 38.

The further components of the central part 18 and the drive part 10 are shown only schematically in Figure 5.

Claims

Claims 1. An industrial truck comprising -a drive part (10) which has at least one drive wheel (12), -a load-bearing part (14) which is configured for receiving a load to be transported, and -a central part (18) arranged between the drive part (10) and the load-bearing part (14) which has a platform (20) on which a driver of the industrial truck may ride and the arrangement thereof determining the ground clearance of the industrial truck in the region of the central part (18), -the load-bearing part (14) being height-adjustable relative to the central part (18) for lifting a load, characterized in that -the central part (18) is height-adjustable relative to the drive part (10).
2. The industrial truck according to Claim 1, characterised in that an actuating device (30) for the drive and/or the steering of the drive wheel (12) is fastened to the central part (18).
3. The industrial truck according to Claim 1 or 2, characterised in that the central part (18) has a guide (24) which guides the load-bearing part (14), so that it is displaceable in parallel relative to the central part (18).
4. The industrial truck according to one of Claims 1 to 3, characterised in that a lifting cylinder (46) is present which is connected to the central part (18) and to the load-bearing part (14), so that it may adjust the vertical position of the load-bearing part (14) relative to the central part (18).
5. The industrial truck according to one of Claims 1 to 4, characterised in that on the load-bearing part height-adjustable rollers (32) or wheels are arranged on a pivot arm (36), the pivoting movement thereof being able to be coupled to the height-adjustable movement of the load-bearing part (14) relative to the central part (18).
6. The industrial truck according to one of Claims 1 to 5, characterised in that a lifting cylinder is present which is connected to the central part (18) and to the drive part (10), so that it may adjust the vertical position of the central part (18) relative to the drive part (10).
7. The industrial truck according to one of Claims 1 to 6, characterised in that the central part (18) and the drive part (10) are connected to one another via a height-adjustable pivot pin and via at least one arm spaced apart from the pivot pin, the one end thereof being pivotably fastened to the drive part (10) and the other end thereof being pivotably fastened to the central part (18).
8. The industrial truck according to Claim 6 or 7, characterised in that a control unit is present by which the lifting cylinder connected to the central part (18) and to the drive part (10) may be controlled independently of the lifting cylinder (46) connected to the central part (18) and to the load-bearing part (14).
9. The industrial truck according to one of Claims 1 to 8, characterised in that the platform (20) of the central part (18) has a standing surface, which is arranged less than mm high above the ground (34) when the central part (18) is fully lowered relative to the drive part (10), and the industrial truck in the region of the central part (18) has a ground clearance of more than 40 mm when the central part (18) is fully raised relative to the drive part (10).
10. An industrial truck substantially as herein described with reference to and illustrated in the accompanying drawings.