GB2135478A

GB2135478A - Industrial truck comprising at least one function drive

Info

Publication number: GB2135478A
Application number: GB08333881A
Authority: GB
Inventors: Erich Kirschneck; Philip Lee
Original assignee: Jungheinrich Unternehmensverwaltung KG
Current assignee: Jungheinrich AG
Priority date: 1983-02-24
Filing date: 1983-12-20
Publication date: 1984-08-30
Also published as: SE8306579D0; FR2541662A1; FR2541662B1; GB8333881D0; SE8306579L; SE448984B; DE3306467A1; GB2135478B; DE3306467C2

Abstract

An industrial truck comprising function drives, which include at least a travel drive (2), a steering drive, a lifting drive (9, 11) in trucks comprising a lifting mast, and a load carrier drive (13, 14, 15). Each function drive comprises electric and/or hydraulic drive motor means and switching and/or automatic control means for said drive motor means and is operatively connected to a travel controller (16), which is mounted on the vehicle and includes a command input station (4) and a travel control microprocessor (22) for generating control signals. A function drive microprocessor (23) is associated with and located adjacent to at least one of said function drives (13, 14, 15). These two microprocessors (22, 23) are connected by a link (26), which consists preferably of a two-line glass fibre cable, by which signals that have been encoded by the travel control microprocessor (22) can be transmitted. One of the function drives preferably constitutes the load carrier drive (13, 14, 15). The function drive microprocessor (23) associated with the load carrier drive (13, 14, 15) is mounted on the load-lifting means (10) and is connected to sensors (27, 28) carried by said load-lifting means. <IMAGE>

Description

SPECIFICATION Industrial truck comprising at least one function drive This invention relates to an industrial truck comprising function drives, namely, a travel drive, a steering drive, a lifting drive in a truck comprising a lifting mast, and/or a load carrier drive, at least one of said function drives comprising electric or hydraulic drive motor means and controlling switching and/or automatic control means associated with said drive motor means, said truck also comprising an electric travel controller, which is mounted on the chassis and connected to said at least one function drive and operable to deliver control signals thereto and including a command input station and a travel control microprocessor, which is operable to deliver output signals to said at least one function drive.

Reference made hereinafter to a drive motor includes always also switching and/or automatic control means.

It is known to provide such industrial trucks with numerous drive means, which are operated in use under manual control or under automatic control, possibly under programmed control, and particularly where a plurality of function drives are provided they are operated in dependence of each other.

The invention is generally concerned with a travel drive which may be controlled in accordance with a certain programme in dependence on the conditions for the travel to a desired location or on the elevation of the load, and with a steering drive, which is controllable under certain conditions, and, if desired, with a lifting drive and particularly with a load carrier drive, which is provided on load-lifting means, which are vertically movable by the lifting drive.

The load-lifting means may consist, e.g., of a lifting carriage. Drives provided on said load-lifting means include a traversing drive, a slewing drive, and if desired, an advancing drive, which may respond to correcting instructions from the desired location. These drives may include electric or hydraulic motors as well as switching and/or automatic control means.

To permit a delivery of correcting instructions and a response of the other function drives to external influences, each of said other function drives is provided with sensors for scanning external signal sources. It is known to provide such signal sources or sensors particularly on load-lifting means or lifting carriages as means for ensuring an exact positioning so that the response to signals coming from the electric travel controller may be overridden in dependence on instantaneous local conditions.

Each of the previously known industrial trucks has been designed for a specific purpose and has been provided with hydraulic or electric drive motors and means for controlling the same, i.e., switches, automatic control systems and control valves. Such arrangements involve a considerable expenditure.

In practice, similar industrial trucks are used for different operations for which only individual drives or combinations of drives are required. For this reason the industrial trucks and their function drives, particularly the drives provided on the load-lifting means, are equipped for their specific purpose. When the industrial truck is to be used for a different operation, the equipment on the truck must be altered, i.e., the existing equipment must be replaced by new equipment, particularly when several movements are to be performed in new combinations.

The above remarks are applicable to the known arrangements in which the microprocessor is incorporated in the electric travel controller of the vehicle. The instruction signals generated by such microprocessors of known design and known arrangements are delivered via numerous lines to the several drive motors and/or switches, automatic control systems and control valves. As many as 32 lines may be provided for this purpose and are combined in a flat cable, which involves a considerable expenditure, particularly when it extends to the load-lifting means or to the carrier, in view of the weight of the flat cable and the need for reels which must be operated in dependence on the vertical movement of the load-lifting means. Such flat cable constitutes also a considerable obstruction at the lifting mast.

Whereas it is also known to arrange such flat cables parallel to chains for driving a telescopic mast, such an arrangement involves also a substantial space requirement and expenditure for guiding means, and supply lines are required in spite of that expenditure.

A further disadvantage of the known design resides in that the connecting cables including numerous conductors, which consist mainly of copper, are susceptible to interference. The larger the length of a connecting cable and the larger the distance travelled by the load-lifting means and the length to which the connecting cable is extended, the more likely is the occurrence of interference due to the inductive coupling to other control means of the vehicle, particularly to pulse generators and the like. Such generators may be included in the igniting means of a travel drive motor or in other controlling drive means for the steering mechanism and the like.

The large number of lines connected to the electric travel controller of the vehicle in the known arrangements is also due to the fact that sensors are provided adjacent to the function drives, particularly at the load-lifting means, and served to scan targets at the desired locations, and signals generated by such sensor must be transmitted downwardly to the microprocessor provided on the chassis, particularly from the load-lifting means, so that said signals can be used in the microprocessor to influence or control the control signals delivered to the drive motors of the function drives, particularly those associated with the load carrier. This involves a high circuit expenditure and time lags.

If such a large number of lines are included in a flat cable, mechanical problems will arise, which ralate to the guidance as far as the lateral alignment is concerned. Kinks may result in defects, which may adversely affect or disable the entire control system.

It is an object of the invention to improve an industrial truck of the kind described first herein before in that the overall equipment is greatly simplified, the load imposed by lines on the loadlifting means or its carriage is reduced, and a breakage of lines is more reliably prevented.

Besides, lines can be provided in a simpler manner than before and have a shorter length and are less susceptible or unsusceptible to interference.

The present invention provides an industrial truck comprising function drives, as ieast one of which comprises electric or hydraulic drive motor means and controlling switching and/or automatic control means associated with said drive motor means, said truck also comprising an electric travel controller, which is mounted on the chassis and connected to said at least one function drive and is operable to deliver control signals thereto and includes a command input station and a travel control microprocessor operable to deliver output signals to said at least one function drive, at least one function drive microprocessor being provided which is located adjacent to said one function drive and which is connected by two lines to the travel control microprocessor whereby encoded signals can be delivered from the travel control microprocessor to the function drive microprocessor, the function drive microprocessor being operable to convert said signals into signals for controlling the controlling, switching and/or automatic control means associated with said drive motor means of said one function drive.

The space requirement and the weight of a microprocessor are negligibly small. For this reason a function drive microprocessor can readily be provided adjacent to the function drive.

From a mechanical aspect and the susceptibility to interference this arrangement results in the important advantage that there is no longer a need for a cable link which includes a large number of lines consisting of material which is susceptible to interference. Because such link consists of only two lines, it is lighter in weight and smaller in size. Special advantages involve the design of the electric travel controller, which may be smaller than before. The safety is increased because in case of a breakage of a line the defect will be recognized immediately so that the supervision is also improved.

The two-line consists preferably of a glass fibre cable.

If the function drives are provided with sensors for scanning signal sources, lines connecting the sensors to the function drive microprocessor are desirably provided. This feature results in the provision or simplified and particularly shorter lines and these lines need not be handled even if the function drives are movable relative to the chassis. For this reason such lines result also in a simplification but still permit of an evaluation and control.

The use of a glass fibre cable multiplies or improves the possibilities for a transmission of signals and ensures that the link will not be susceptible to interference, particularly by electromagnetic pulses. The waveform of signals will be preserved and the link is lighter in weight, thinner and more reliable. The connection of the sensors to the function drive affords the advantage that control means can be operated in a more direct manner.

A special advantage will be afforded if the function drive microprocessor includes a programme memory and is connected to the travel control microprocessor. The function drive microprocessor includes circuitry and comparator means which in response to signals from the travel control microprocessor and from the programme memory initiate the performance of a programmed sequence of operation by the microprocessor associated with the load-lifting means. This permits a very simple design of the hardware.

In connection with the reference made hereinbefore to function drives, which include the load carrier drive, a particularly preferred embodiment of the invention relates to the connection of the drive motors for the load carrier and the associated switching and/or automatically control means, namely the motors of a traversing drive, a slewing drive and, if desired, an advancing drive. In that embodiment the function drive microprocessor is desirably mounted on the load-lifting means and the sensors are also mounted on the load-lifting means. The microprocessor on the load-lifting means may suitably comprise a programme memory.

The advantages set forth hereinbefore will produce particularly desirable results if a function drive microprocessor is mounted on the loadlifting means. This is due to the fact that the connecting lines are wound up or deflected in dependence on the elevation of the carriage or of the load-lifting means. In that case, the lighter weight and higher flexibility will be particularly desirable. The size is also reduced and this will substantially contribute to the improved vision of the driver if the link extends along the mast.

The invention will now be explained with reference to a preferred illustrative embodiment, which is shown on the drawings, in which: Figure 1 is a diagrammatic side elevation showing an industrial truck, which consists of a fork-lift truck; this figure serves to illustrate the drives; Figure 2 is a diagrammatic view showing a known design; and Figure 3 is a diagrammatic view showing a design according to the invention; corresponding sub-assemblies are shown also in Figure 1.

The industiral truck shown in Figure 1 comprises a chassis 1, which is adapted to be driven by a drive motor 2, also a driver's seat 3 and an associated command input station consisting of a control panel 4, and a steering wheel 5 for steering at least one steerable wheel 6, which may constitute a driven wheel. The other wheels, one of which is designated 7 may be rigid or may consist of casters. A lifting mast 8 is also provided, which consists particularly of a telescopic mast and has suitable drive means 9 associated with it The load-lifting means 10 consist of a lifting carriage, which is vertically movably mounted on said lifting mast. A drive motor 11 is provided for that purpose. The loadlifting means carry a load carrier 12.Associated with the load carrier 1 2 are a traversing drive motor 13, a slewing drive motor '14 and, if desired, an advancing drive motor 15.

The drive motors may consist of electric or hydraulic motors and they have switching and/or automatic control means associated with them.

These switching and automatic control means are included in the representations of the motors in Figure 1. Said three drive motors 13 to 1 5 constitute a function drive, namely, the load carrier drive.

The drive motors 13 to 1 5 as well as their associated switching and/or automatic control means are operatively connected to an electric travel controller 1 6 by a link 1 8 indicated by a dash-dot line. The electric travel controller 1 6 is connected to the command input panel 4 by a line 1 7. From the electric travel controller, additional lines may extend to other so-called function drives, such as the travel drive, steering drive and/or lifting drive. Such different lines are provided in the same manner as the line leading to that function drive which constitutes the load carrier drive.

The link 18 is of great importance. Each of the drive motors 1 3 to 1 5 mounted on the load-lifting means 10 has switching and/or automatic control means associated with it, which are included in the drives. Service or supply lines generally designated 1 9 are also provided, which extend from a supply source 32 that is provided in the vehicle and may comprise voltage source or a hydraulic pressure source. Valves and/or controllers associated with a hydraulic pressure source or switches and/or electric controllers associated with a voltage source may be mounted on the load-lifting means.

The service or supply lines 1 9 lead to the several drive motors 13 to 15 and to the switching and/or automatic control means associated with such motors.

In the known embodiment shown in Figure 2, the electric travel controller 1 6 comprises a microprocessor 20. The means for transmitting instructions to the drive motors 13 to 1 5 and the switching and/or automatic control means associated therewith comprise a multi-line cable link, which constitutes the link indicated by a dash-dot line. This involves a higher expenditure.

If such microprocessor 20 is provided, additional lines will be required in the cable links if additional signals are to be delivered to the microprocessor 20 from sensors, which may be mounted on the load-lifting means and are designated 27 and 28 in Figure 3. Expensive mechanical means and controls are required for a movement of such multi-line cable link in dependence on the vertical movement of the load-lifting means 10.

In accordance with Figure 2 a multi-line cable link comprising 20 to 30 lines extends to the load-lifting means 10 from the electric travel controller 16, which includes the microprocessor 20. Such an arrangement involves great difficu Ities.

In accordance with Figure 3 these difficulties are eliminated in that the functions of the known microprocessor 20 are divided between a travel control microprocessor included in the electric travel controller 1 6 and a function drive microprocessor 23 mounted on the load-lifting means 1 0. The function drive microprocessor 23 comprises a control signal generator 24 connected to the drive motors 13, 14, 15 or the control or switching means 25 preceding said drive motors.

In that embodiment the travel control microprocessor 22 and the microprocessor 23 mounted on the load-lifting means are interconnected only by two-line link 26, which preferably consists of a glass fibre cable having two cores, which are braided or insulated and afford the advantages mentioned above.

Important advantages are afforded because the microprocessor mounted on the load-lifting means has a small space requirement and is light in weight and signals received at the load-lifting means may also be processed at the load-lifting means. For instance, the load-lifting means may be provided with sensors, which are adapted to cooperate with reflectors, signal generators or the like means provided on a shelf or a target and are connected by a link or lines 29, 30 to the microprocessor mounted on the load-lifting means. In such an arrangement, correcting signals delivered by the sensors 27, 28 can be utilized at the load-lifting means in various ways.

The microprocessor 23 mounted on the loadlifting means may be provided with a programme memory 31. By signals received from the travel control microprocessor 22 via the link 26, the programme memory 31 can be addressed to initiate a programmed sequence of operations at the load-lifting means 10. This will result in a further simplification of the known arrangements.

Whereas Figure 1 shows generally a microprocessor 20 which is included in the electric travel controller 16, Figure 1 shows also that the microprocessor functions are divided between a travel control microprocessor 22 and a function drive microprocessor 23, which is spaced from the microprocessor 22 and in the present case is mounted on the load-lifting means. These two microprocessors can be connected by a twoline link and relatively simple plug connectors.

This is another advantage over the previously known wide fiat cables, which include e.g., 30 or 32 lines.

Claims

1. An industrial truck comprising function drives, at least one of which comprises electric or hydraulic drive motor means and controlling switching and/or automatic control means associated with said drive motor means, said truck also comprising an electric travel controller, which is mounted on the chassis and connected to said at least one function drive and is operable to deliver control signals thereto and includes a command input station and a travel control microprocessor operable to deliver output signals to said at least one function drive, at least one function drive microprocessor being provided which is located adjacent to said one function drive and which is connected by two lines to the travel control microprocessor whereby encoded signals can be delivered from the travel control microprocessor to the function drive microprocessor, the function drive microprocessor being operable to convert said signals into signals for controlling the controlling, switching and/or automatic control means associated with said drive motor means of said one function drive.

2. An industrial truck according to claim 1, characterized in that said two lines are incorporated in a glass fibre cable.

3. An industrial truck according to claim 1 or 2, comprising sensors which are provided at said one function drive and serve to scan signal sources, characterized by lines between said sensors and the function drive microprocessor associated with said one function drive.

4. An industrial truck according to any of claims 1 to 3, characterized in that said function drive microprocessor includes a programme memory, which is connected to the travel control microprocessor, and circuitry and comparator means for initiating a programmed sequence of operations to be performed by said function drive microprocessor under the control of signals delivered by said travel drive microprocessor and of said programme memory.

5. An industrial truck according to any of claims 1 to 4, wherein said one function drive comprises a load carrier drive having a traversing drive motor, a slewing drive motor, and, if desired, and advancing drive motor, and switching and/or control means associated with said drive motors, for operating a load carrier of load lifting means, characterized in that said function drive microprocessor is mounted on the load-lifting means and sensors for scanning signal sources are mounted on said load-lifting means and connected by lines to said function drive microprocessor mounted on said load-lifting means.

6. An industrial truck according to claim 4 and 5, characterized in that said function drive microprocessor provided with said programme memory is mounted on load-lifting means.

7. An industrial truck substantially as herein described with reference to Figures 1 and 3 of the accompanying drawings.