NZ500575A - Loading plank operating system including an electric motor associated with each lift actuating mechanism - Google Patents

Abstract

A lift-type loading platform system (10), to be mounted on a motor vehicle (11), particularly a truck, comprises two substantially parallelogram support structures (13,14), which are generally mutually parallel and spaced a distance apart, a plate-like loading platform (15) mounted on the supporting structures (13,14), for raising and lowering a load disposed on the loading platform (15), and electric motors (160,170) associated with hydraulic cylinders (16,17) for controlling the hydraulic circuit to lift or lower the platform (15).

Description

No: Date: NEW ZEALAND PATENTS ACT, 1953 COMPLETE SPECIFICATION LOADING PLANK OPERATING SYSTEM WITH LIFTING ACTUATOR We, SORENSEN HYDRAULIK, ZWEIGNIEDERLASSUNG, ULFBORG, FILIAL AF SORENSEN HYDRAULIK GMBH, TYSKLAND, a Danish company of Industriarealet 54, DK-6990 Ulfborg, Denmark, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: (followed by page - la -) intellectual property office of NZ i 2 oct 1999 Received ^575 LOADING PLANK OPERATING SYSTEM WITH LIFTING ACTUATOR BACKGROUND OF THE INVENTION The invention relates to a loading plank operating system including a lifting actuator particularly for trucks including a lifting mechanism with parallel spaced lifting arms supporting an essentially plate-like plank for carrying a load to be raised or lowered and optionally for closing a storage space of a vehicle. The operating system further includes a lifting actuator for raising and lowering the loading plank and optionally a pivot actuating mechanism for pivoting the loading plank between a horizontal and a vertical position.

In this specification, including the claims, the terms "loading plank", "loading board" and "loading platform" are to be understood as being equivalent and to include a loading tail-board or a loading side-board.

Such a loading plank operating system is known from EP-A 0 808 747. Such systems are used especially in connection with trucks in order to facilitate the unloading of loads transported by the trucks by lowering the loads on the loading planks onto the surface on which the truck is disposed. Then the load can be further transported to its destination. The same is true for the loading procedure of a truck. In this case, the load is placed onto the loading plank, which has been lowered onto the ground or pavement on which the truck is disposed. The loading plank is then raised to the truck loading bed platform level and is then moved onto the loading bed. When the unloading or loading procedure is completed, the loading plank is tilted in some systems from the horizontal position in which it is maintained during the loading or unloading procedure to a vertical position to close the rear end of the loading bed or the loading compartment. In other loading plank operating systems, the loading plank is folded and moved or pivoted below the loading bed of the truck.

INTELLECTUAL PROPERTY OFFICE OF N.Zla INTELLECTUAL PROPERTY I \JLIBRARY\ALC\SPECS\4143 85 NHG 3 1 jul 2001 RECEIVED For the raising and lowering of the loading plank in an essentially horizontal position during the loading and unloading procedure from the level of the loading bed, a so-called lift actuating mechanism is utilized which is operated hydrau-lically, pneumatically or electrically or by a combination of these mechanisms. For the tilting of the loading plank from a vertical to a horizontal position and vice versa in order to open or close the loading space, a tilting actuator device is used which is also operated m the manner described earlier. Load plank and wall systems of this type may therefore include at least one actuator, which cooperates with at least a support structure of a parallelogram-like lift or tilt structure. If at least one lifting actuator mechanism and at least one tilting actuator mechanism are present, the lifting actuator mechanism cooperates with the one operating mechanism for the paral-lelogram-like lifting and tilting mechanism whereas the tilting mechanism cooperates with the other operating mechanism.

If a tilting actuating mechanism is present the lifting actuator mechanism and the tilting actuator mechanism are controlled by a control structure arranged at a suitable location on the truck. In this way, lifting and lowering movements of the loading plank and also tilting movements thereof between its horizontal and vertical positions can be performed. The respective operating control signals are given by an operator by means of suitable operating elements provided on the control structure. Generally, a hydraulic operating system is provided for the operation of the lift actuator or actuators and, if present, the tilt actuator or actuators. Hydraulic pressure is t provided by a central hydraulic system including one or several electric motor driven pumps. By suitable valve means arranged between the pumps and the lift and, if applicable, the tilt actuator, the respective actuator can be operated. If a loading plank wall system includes for example a multitude of actuators - what is usually the case - for example, one or two lifting actuators and, if present, one or two tilt actuators, all these actuators are in communication with a valve or, respectively, a valve block by way of hydraulic control lines. The hydraulic valve control arrangement is m communication, by way of the valve or valve block, with the cylinder piston structures of the lift and pivot actuators. In addition, the hydraulic system includes a tank, one or several of the pumps mentioned before, one or several electric motors, relay controls etc., and a central control unit by which the loading plank wall system is controlled. Consequently, after the loading plank arrangement is installed m a vehicle, there are still many electrical and hydraulic line connections to be established to make the whole system operative. Obviously, this involves a substantial amount of manual labor concerning the installation and mounting whereby the whole system becomes basically very expensive. Furthermore, there are storage costs for storing the various parts and there are costs for the administration of the parts and equipment storage.

Another serious problem involving the present loading plank systems resides m the fact that the space required for the multitude of electrical and hydraulic control lines and all the other control devices is not available m small vehicles. Consequently, such loading plank systems cannot be utilized m connection with small vehicles although there would be a need for smaller vehicles with loading systems. Another problem with present plank loading systems resides in the fact that the whole plank loading system becomes unusable when for example a hydraulic actuator fails, for example, by a defect in a hydraulic line. The plank loading system loses even minimum functionality so that a vehicle including such a loading system must be repaired wherever the loading system malfunctioned and cannot be driven to a repair shop since the loading plank cannot be lifted off the ground nor can it be tilted.

It is therefore the object of the present invention to provide a loading plank system which uses only a relatively small amount of parts and components without limiting the functionality of the system, which is safer in operation than any of the loading system presently available and which can be easily and inexpensively installed in a vehicle with which it is to be used. The system should also be adequate for use with relatively small vehicles, which, so far, could not be equipped with loading systems, it should be simple in its design and it should be relatively inexpensive. It also should be easy to manufacture and install. Furthermore, storage costs for its parts should be low.

The invention may broadly be said to consist in a loading board operating system for mounting on a vehicle, comprising two substantially parallelogram-like supporting structures disposed in spaced relationship, a platform-like loading board mounted on said supporting structures for raising and lowering a load disposed on said loading board and optionally for closing a cargo bed of the vehicle, a lift actuating means for raising and lowering said loading board and, optionally, a tilt actuating means for tilting said loading board between substantially horizontal and vertical positions, said lift actuating means having a first electric motor associated therewith for operating the lift actuating means for raising and lowering said loading board.

The loading plank operating system according to the invention provides for a decentralization of the drive for the lifting mechanism, that is, each lifting actuator includes its individual electric drive motor. As a result only an electrical cable needs to extend to the control structure mounted on the vehicle. The electrical cables are pre-assembled and have electrical connectors by which they can be easily connected to the central control unit whereby the unit becomes instantly fully operational. The installation of all the components required for the operation of the loading plank operating system can therefore be completed during the manufacture of the loading plank control system so that SUMMARY OF THE INVENTION I \LIBRARY\ALC\SPECS\414385 NHG INTELLECTUAL PROPERTY OFFICE OF N.Z.

INTELLECTUAL PROPERTY j 1 jul 2001 R ECEIVED RECEIVED it need only be attached to a vehicle. Another important advantage of the loading plank operating system according to the invention resides in the fact INTELLECTUAL PROPERTY OFFICE OF N.Z.

INTELLECTUAL PROPERTY OFFICE OF N.Z. j 1 jul 2001 RECEIVED I \LIBRARY\ALC\SPECS\414385 NHG 4a ff. R "V " that, with each of the lifting actuating mechanisms having its own electric drive motor, emergency operation can be maintained if, for example, one of two loading plank operating mechanisms or the electric drive motor thereof fails. It is quite apparent that the costs of storing the necessary replacement parts are reduced for such a simplified system. Consequently, also the requirements for the administration of the parts storage is reduced if no complicated hydraulic systems are employed.

In an advantageous embodiment of the invention also the load plank tilting mechanism is operated by electric motors. This arrangement has the same advantages as already pointed out with respect to the loading plank lift system. This is also true for the loading plank tilting systems, which employ two or more tilting actuating devices.

An electric motor associated with a lift actuating mechanism and, if applicable, with a tilt mechanism may be disposed at any suitable location m the vicinity of the lift and/or tilt mechanism. It has been found to be advantageous if the electric motor is disposed directly at the lift and/or tilt mechanism so that the force transmission path from the electric motor, that is, the motor shaft to the lift or tilt mechanism is short. In this way, the need for force transmission elements and hydraulic elements for the operation of the lift and/or tilt mechanism is at a minimum. Furthermore, the mounting of the electric motor directly on the lift actuator or the tilt actuator mechanism facilitates the servicing of the motor and the exchange of the motor if it should fail. It also facilitates the exchange of the whole lift or tilt operating mechanism together with the motor by a replacement of the whole module.

Advantageously, the loading plank operating system includes the electric motor as an integral part of the lift or the tilt actuating mechanism. In this case, the electric motor operates the lift or tilt mechanism directly by way of a me- INTELLECTUAL PROPERTY OFFICE OF N.Z. 3 1 JUL 2001 RECEIVED RECEIVED chanical device such as a threaded spindle or similar device. No hydraulic operating mechanism is used m this case. If appropriately designed such a mechanism is well suited for loading plank operating systems for relatively small vehicles and 5 relatively small loads.

It is also advantageous if the lift and/or tilt operating mechanism is a hydraulically operated piston and cylinder arrangement wherein the electric motor is utilized only to drive a pump to provide fluid under pressure specifically for a par-10 ticular operating mechanism for lifting and lowering and tilting the loading plank. In this case, the loading plank design is practically the same as that of conventional loading plank mechanisms with the exception that each operating mechanism has its independent pressurized hydraulic fluid supply. A small 15 hydraulic fluid reserve, which is normally contained m tanks, may be provided individually for each operating mechanism in so-called pads. The pads are carried along so that they are available when there is a need for hydraulic fluid. Such a conventional operating mechanism still has the advantages as 20 pointed and above as the individual operating systems are independent of each other and can be replaced individually.

In finally another advantageous embodiment of the loading plank operating system according to the invention, the electric motor for operating the lift and/ or tilt operating mechanism 25 is centrally controllable. Such a central control is achieved for example by means of an operating control board structure, which is manufactured to include all the connections to the various electric motors, switches, operating buttons and any additional electric equipment. A control board so equipped 30 only needs to be mounted on the vehicle and a suitable electrical cable connection to the vehicle electric system needs to be established. Once this is done, the loading plank and its operating system are ready for use. 6 An embodiment of the invention will be described below in greater detail on the basis of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a conventional loading plank with an operat-5 ing system wherein all the electrical and hydraulic lines extending to a control board need to be installed individually, the hydraulic lines however not being shown in the figure, and Fig. 2 shows a loading plank with operating mechanism according to the invention, wherein an electric motor is mounted 10 directly to a plank tilting mechanism and another electric motor is directly connected to a loading plank lifting mechanism.

DESCRIPTION OF A PREFERRED EMBODIMENT First, reference is made to Fig. 1, which shows a conventional loading plank operating system. Conventional loading 15 plank systems 10 are well known so that their operation and design are explained only shortly. A typical loading plank system 10 is disclosed for example in EP-A-0 808 747 to which reference is made therefore. In the loading plank system disclosed therein only a single lift actuating mechanism 16 is 20 provided by which the loading plank 15 can be raised and lowered vertically. The loading plank may carry a load, which is not shown which load is to be raised for example from a pavement to a height corresponding to the load bed of a vehicle 11. This facilitates movement of the load onto the vehicle load 25 bed. The vehicle 11 is represented only by the frame members of the vehicle, which is sufficient for an understanding of the loading plank system 10. The tilting actuating mechanism 17 permits tilting of the loading plank 15 from a horizontal position as shown in Fig. 1 to a vertical position. In the verti-30 cal position, the loading plank 15 may, for example, close the load bed of the vehicle 11. The loading plank can be tilted back to a horizontal position for opening the load bed to permit unloading of a load. 7 It is pointed out that so-called folding loading planks which can be stored in a suitable place between the loading bed and the frame of a vehicle 11 do not require a tilt mechanism 17 since the folding feature is not necessary of the loading plank-wall system 10.

In the loading plank-wall system 10 as shown in Fig. 1, the lift actuating mechanism 16 and the tilt actuation mechanism 17 are shown symbolically. In Fig. 1, only one hydraulic line is symbolically shown connected to a valve block and including a hydraulic fluid tank. The hydraulic system includes one or several pumps which may be operated by one electric motor or several electric motors which are also not shown but which generate the required hydraulic fluid pressure. The control mechanism 18 mounted on the vehicle is connected in a well-known manner by electric control cables with the hydraulic circuit including control elements such as relay switches and sinister elements m a well known manner. In this way, the standard movements of the loading plank such as vertically raising and lowering and tilting from a vertical position to a horizontal position and vice versa can be achieved by hydrauli-cally operated lifting actuators or, respectively, tilting actuators .

The loading plank operating system 10 according to the invention as shown m Fig. 2 differs from that shown m Fig. 1 essentially by the fact that each lifting mechanism 16 and the tilt mechanism 17 includes an electric motor 160, 170. The electric motors 160, 170 are arranged in the loading plank operating system as shown m Fig. 2 at the side of the lift actu-atmg mechanism 16 or the tilt actuating mechanism 17. This arrangement is only exemplary. It is included to indicate the association of the electric motors 160, 170 with the respective lift or tilt actuation mechanism.

The electric motors 160, 170 may also be part of the lift and/or tilt actuation mechanism 16, 17, that is, they may be disposed in the respective actuation mechanisms. On the other hand, the lift and/or tilt mechanism may be conventional using hydraulically operating piston-cylinder arrangements. Then, the electric motors are connected to pumps providing pressurized hydraulic fluid for operating the piston cylinder arrangements to effect actuating movement of the actuating mechanisms 16, 17 hydraulically m the conventional manner. The electric motor 160 is then connected to a pump supplying hydraulic fluid under pressure to the lift actuating mechanism 16 and the electric motor 170 is connected to a pump supplying hydraulic fluid under pressure to the tilt actuating mechanism 17 for moving the loading plank for example from a vertical to a horizontal position.

The loading plank operating system 10 according to the invention can be mounted to a vehicle 11 in the way shown for example in EP A 0 808 747. Like the conventional operating systems, it includes an essentially parallelogram-like lift and/or tilt mechanism 12 including two spaced, parallel support structures 13, 14 supporting the plate-like loading plank 15 m a conventional manner. In the drawings, the plank 15 is shown as a single board, but it may be a foldable board that is a fold-able loading plank as mentioned earlier.

Claims (9)

WHAT WR CLATM TB :

1. A loading board operating system for mounting on a vehicle, comprising two substantially parallelogram-like supporting structures disposed in spaced relationship, a platformlike loading board mounted on said supporting structures for raising and lowering a load disposed on said loading board and optionally for closing a cargo bed of the vehicle, a lift actuating means for raising and lowering said loading board and, optionally, a tilt actuating means for tilting said loading board between substantially horizontal and vertical positions, said lift actuating means having a first electric motor associated therewith for operating the lift actuating means for raising and lowering said loading board.

2. A loading board operating system according to claim 1, wherein a second electric motor is associated with said tilt actuating means for effecting tilting of said loading board.

3. A loading board operating system according to claim 1, wherein said first electric motor is arranged directly at said lift actuating means.

4. A loading board operating system according to claim 2, wherein said second electric motor is arranged directly at said tilt actuating means.

5. A loading board operating system according to claim 1, wherein said first electric motor is an integral part of said lift actuating means.

6. A loading board operating system according to claim 2, wherein said second electric motor is an integral part of said tilt actuating means. I \LIBRARY\ALC\SPECS\414385 NHG INTELLECTUAL PROBITY OFFICE OF N.Z. INTELLECTUAL PROPERTY OFFICE OF N.Z. 3 1 jul 2001 RECEIVED ^0 w w K 'iJ

7. A loading board operating system according to claim 1, wherein said lift and tilt actuating means include hydraulically actuated piston and cylinder arrangements.

8. A loading board operating system according to claim 1, wherein said first electric motor is controllable by a central control arrangement.

9. A loading board operating system according to claim 2, wherein said first and second electric motors are controllable by a central control arrangement. Sfci'ertSen UjdmviVlt, &*«•('gv\ie.<U/ iassavij Ulft>o f J iolftf It GwibV), orised agents INTELLECTUAL PROPERTY OFFICE OF N.Z. » 1 jul 2001 RECEIVED INTELLECTUAL PROPERTY .7. i<juu2mc RECEIVED I \L1BRARY\ALC\SPECS\414385 NHG 11