KR20070048565A - Lifting device for freight - Google Patents

Abstract

The present invention proposes a lifting device for lifting a load, having a load receiving device 10 that can be lifted and lowered by the linear drive devices 13, 14. The fluid actuated cylinder device 16, 17 exerts an upward force on the cargo receiving device 10, in which case the fluid pressure on the actuated cylinder device 16, 17 can be adjusted, thereby providing individual cargo. The portion of the cargo weight acting down is compensated for. The lifting force to be provided from the linear drive device 13, 14, according to the prior indication of the fluid pressure to the working cylinder device, thus formed according to the individual cargo weight, is always quick and simple to the same optimum value. Can be set.

Description

Lifting device for lifting loads {LIFTING DEVICE FOR FREIGHT}

1 is a schematic perspective view of a lifting device with two linear drives and one load compensation device consisting of two working cylinders.

2 is a schematic block circuit diagram for explaining a method of operation.

    Explanation of symbols on the main parts of the drawings

9: longitudinal slot 10: lifting table

11: roller track 12: base frame

13, 14: linear drive unit 15: driven unit

16, 17: working cylinder 18: electronic control unit

19: pressure regulating valve 20: pressure source

21: pressure sensor 22: memory

23: reading device

The present invention relates to a lifting device for lifting a load, comprising a load receiving device that can be lifted and lowered by a linear drive.

In such lifting devices, special problems arise when cargoes of very different sizes must be lifted by the same linear drive. In this regard, in very simple cases the linear drive must adjust its lifting force to the largest load. The disadvantage of such an operation is that a very large linear drive can no longer perform the same type of steady motion when the load to be processed is very small. A known solution to this problem is to design a linear drive for relatively small loads of load depending on the power, and to provide a compensation weight applied upwards when larger loads appear. This solution has the disadvantage that the compensation weight must be changed continuously and adjusted for the individual cargo.

The above problem arises, for example, when transferring a glass substrate (glass plate) in the manufacture of a TFT-screen. Glass substrates typically have a size of 2 meters by 2 meters and are transported while inserted in a rack. The weight of such shelves can reach up to 800 kg. In the case of transporting such shelves through a production site or storage warehouse, the shelves must be lifted and then lowered separately to pass through the transverse passages in order to leave the transverse passages used as escape routes empty according to the relevant regulations. Should be. Since the glass substrate is very sensitive to vibrations, vibrations should be prevented when lifting and lowering shelves. In the case of a larger design of the linear drive device for lifting and lowering the lathe, according to the problem mentioned at the outset, a compensating weight having the aforementioned disadvantages is used in a known manner.

An object of the present invention is to produce a lifting device for lifting a load, which can operate without vibration even when the size of the load is very different, without having to adjust the compensation weight according to the situation.

The problem is solved by a lifting device having the features of claim 1 according to the invention.

Preferably, the fluid pressure of the floating working cylinder device can be set variably, so that the weight of the cargo is compensated for in all cargo, and this compensation of force ensures that the linear drive is always in the optimum range with the same drive force. It can work. In this case the setting of the fluid pressure can be carried out quickly and simply, and can be adjusted to the individual cargo. Doing so always results in very constant and vibration-free lifting movements for all cargoes of different sizes.

The means described in the dependent claims enable preferred embodiments and improvements of the lifting device described in claim 1.

The linear drive device is preferably formed as at least one electric or pneumatic linear drive and preferably consists of a plurality of parallel individual linear drives, in order to form a lifting force of symmetry wherever possible.

The fluid pressure on the actuating cylinder device to create the compensating force can preferably be set or adjusted to a constant value depending on each individual load. For this purpose, the actuating cylinder device is preferably connected to a pressure source via a pressure regulating valve device at a preset pressure.

In order to form a compensating force of symmetry as much as possible, the working cylinder arrangement is likewise made up of a number of parallel individual working cylinders.

By adjusting the fluid pressure of the actuating cylinder device to form a compensating force according to the individual cargo weight in a preferred manner, the driving force of the linear drive required to lift the load is actually always the same. In this case, the driving force to be provided by the linear drive device for the purpose of lifting the cargo corresponds to the difference between the cargo weight and the compensating force. In order to achieve as continuous and vibration free operation as possible, the driving force of the linear drive device is preferably set in the best operating power range.

In order to be able to carry out the adjustment of the compensation force as automatically as possible, a device for displaying and / or defining the weight of the cargo is provided, in which case the cargo weight is automatically detected and the compensation force is automatically determined according to the cargo weight. An automatic adjustment device for adjusting is provided. In this case, the device for displaying and / or defining the cargo weight by means of a fully automatic control method may comprise a scale. Alternatively or additionally, a memory device for inputting cargo weight and / or compensating force may also be provided, in which case the automatic adjustment device is provided with a reading device for reading out and storing the contents of the storage, and from the storage contents in advance Calculate the fluid pressure to be set.

The memory device may be formed as an electrical, magnetic or bar code-memory device. Advance indication of the contents of storage can be done automatically by the balance or manually.

The cargo holding device is preferably formed as a lifting table.

One embodiment of the invention is shown in the drawings and described in detail below.

The lifting device shown as an embodiment of the invention in FIG. 1 is used to lift and unload cargo. The individual loads are placed on a lifting table 10 formed as a cargo holding device, for which purpose two roller tracks 11 are arranged on the lifting table 10. Instead of the roller tracks 11 other devices may be used to facilitate the movement of the cargo, for example air cushion guide devices, sliding rails, roller rails or transport devices, which may all be omitted in the simplest case. Can be used.

In the plate-shaped base frame 12, which may be formed in a frame form or have a different base shape, two vertical linear drives 13, 14 are each centered on opposite sides of the base frame 12. It is installed. As said drive part, it can be an electric or fluid linear drive part 13 and 14, for example. The follower 15 protrudes from the longitudinal slot 9 of the linear drive 13, 14, in which only one follower can be seen from the follower. The follower 15 is arranged in a separate drive element of the linear drive 13, 14, for example in a fluid piston in the case of a fluid drive or spindle, in a drive belt or in a magnetic rotor in the case of an electric drive. have. All known types of linear drives can be used for this purpose. Fluidic drive cylinders used as linear drives are for example formed as so-called slot cylinders, for example known from EP 0 612 377 B1 or EP 1 182 359 B1, in which case the follower is flexible in the remaining areas. Protrudes through the slot of the sealed cylinder.

At two opposite corners of the base frame 12 two fluid actuating cylinders 16, 17 are arranged vertically, which actuate cylinders to form a compensating force according to the cargo to be lifted individually. As a result, the linear driving units 13 and 14 inevitably generate the same driving force regardless of the size of the individual cargo. If two linear drives 13, 14 are designed for an optimal overall driving force of 500 N, for example, and a cargo weighing 8000 N must be lifted, the fluid actuated cylinders 16, 17 are generally 7500 Must generate N compensation. In other words, the working cylinder must be provided with a constant fluid pressure which results in a compensating force of 7500 N.

If the required lifting length is not too long, slot cylinders or conventional cylinders may also be used as the fluid working cylinders 16 and 17. The arrangement state and the number of the linear drives 13, 14 and the working cylinders 16, 17 are of course variable. Thus, for example, even at all four corners of the base frame 12, fluidic actuating cylinders 16, 17 of the same type can be arranged to form a compensating force, or actuating cylinders and linear drives. Placement between is done in the opposite way. In this case, in order to load or transfer the cargo in a sliding manner, one side of the lifting table 10 should preferably be emptied.

The linear drives 13, 14 and the actuating cylinders 16, 17 can also be arranged inside the lifting cage or the lifting shaft or the lifting shaft. In addition, in order to ensure the necessary stability of the lifting device, the vertical linear drive 13, 14 and the fluid actuating cylinders 16, 17 must naturally be supported and fixed in the required manner. In the schematic diagram according to FIG. 1, the above illustration of the support or shaft is omitted for simplicity of the drawings.

According to the block circuit diagram shown in FIG. 2, the two linear drives 13, 14 are controlled and positioned by one electronic control device 18, in which case the linear drives 13, 14 are preferably It is formed as a positioning drive and includes a corresponding path (distance) measurement system, not shown. In a simpler form, a limit switch may be provided to initiate the lifting operation or the lowering operation in the highest position and the lowest position. The electronic control device 18 may be formed and / or include at least one controller, for example as a programmable logic controller.

By means of the electronic control device 18 the two fluidic actuating cylinders 16, 17 are also regulated via one pressure regulating valve 19, which pressure regulating valve is for example formed as a pressure regulating proportional valve. It became. Of course, one unique pressure regulating valve may also be assigned to each working cylinder 16, 17. In the electronic control device 18, the fluid pressure necessary for forming the compensating force is calculated and provided to the pressure regulating valve 19 as a set value. The pressure regulating valve is connected to the pressure source 20 and regulates the predetermined fluid pressure as a setpoint in the working cylinders 16, 17 to a corresponding constant value according to the individual load. For this purpose, pressure is detected by the pressure sensor 21 and provided to the pressure regulating valve 19 as an actual value. The actual value can in principle also be transmitted to the electronic control device 18, so that the control device directly provides a corresponding control signal to the pressure regulating valve 19 formed as a proportional valve instead of the set value.

In the case where the linear drives 13, 14 are likewise formed as a fluid working cylinder, the control of the drive is, of course, through at least one pressure regulating valve which can likewise be formed as a proportional valve. Pressure regulating-proportional valves of this type for regulating the input are known, for example, from DE 202005006127 U.

In order to automatically adjust the compensation force by instructing the predetermined fluid pressure in advance, a cargo or cargo weight is input into the memory 22. As the memory, a magnetic memory or an electronic memory can be handled. In this case, a bar coding device can also be used as the memory device. The memory 22 is either present directly in the cargo or in a device for receiving the cargo, such as a pallet. When the load is lifted on the lifting table 10 or conveyed in a sliding manner, the value of the load is read out by the wireless reading device 23 at the lifting table or in front of the lifting table so that the electronic control device 18 Is provided. Since the linear drive 13, 14 must always provide the same driving or lifting force regardless of the size of the load, the difference between the load weight and the lifting force is calculated in the electronic control device 18. This difference results from the compensating force to be provided by the working cylinders 16, 17. Thus, in order to set or adjust the corresponding fluid pressure, the control device 18 generates a control signal for the pressure regulating valve 19, corresponding to the compensating force.

As the transportation of the cargo or the corresponding cargo receiving device is carried out through a scale which automatically reads and inputs the measured value into the memory 22, the process of inputting the cargo weight into the memory 22 can also be automatically performed. . In this case it is also possible, in principle, to integrate the balance in the lifting table 10.

According to the lifting device for lifting a cargo according to the invention, a device for indicating and / or defining the cargo weight is provided to automatically detect the cargo weight. In addition, an automatic setting device for setting the compensation force according to the cargo weight detected by the device for indicating and / or defining the cargo weight is provided so that it is not necessary to adjust the compensation weight according to the situation, It is possible to produce lifting devices for lifting loads that can operate without vibration even in very different cases.

Claims (14)

A cargo receiving device 10 that can be lifted and lowered by linear drive devices 13, 14, and a fluid actuated cylinder device 16, 17 that applies upward force to the cargo receiving device 10. A lifting device for lifting a load, comprising: A lifting device in which the fluid pressure of the fluid working cylinder device can be adjusted such that a portion of the cargo weight acting down by the individual cargo is compensated. The method of claim 1, Lifting device, characterized in that the linear drive device (13, 14) is formed as at least one electric or compressed air linear drive. The method according to claim 1 or 2, Lifting device, characterized in that the linear drive device (13, 14) consists of a plurality of individual linear drives in parallel. The method according to any one of claims 1 to 3, Lifting device, characterized in that the fluid pressure for the actuating cylinder device (16, 17) can be set or adjusted to a constant value, respectively, according to the individual load. The method of claim 4, wherein Lifting device, characterized in that the working cylinder device (16, 17) is connected to the pressure source via a pressure regulating valve device (19). The method according to any one of claims 1 to 5, Lifting device, characterized in that the working cylinder device (16, 17) consists of a plurality of individual working cylinders in parallel. The method according to any one of claims 1 to 6, Since the fluid pressure of the actuating cylinder device 16, 17 can be adjusted to form a compensating force according to the individual load weight, the driving force of the linear drive device 13, 14 necessary to lift the load is always actually A lifting device characterized by the same. The method of claim 7, wherein The lifting device, characterized in that the driving force to be provided from the linear drive device (13, 14) for lifting the load corresponds to the difference between the load weight and the compensating force. The method according to claim 7 or 8, Lifting device, characterized in that the driving force of the linear drive device (13, 14) can be adjusted in the optimum operating power range. The method according to any one of claims 7 to 9, A device (22) is provided for indicating and / or defining cargo weight, and an automatic setting device for automatically detecting the cargo weight and setting the compensating force according to the cargo weight. The method of claim 10, Lifting device, characterized in that the device (22) for displaying and / or defining cargo weight comprises a scale. The method of claim 10 or 11, The apparatus 22 for indicating and / or defining cargo weight comprises a memory device for inputting the cargo weight and / or compensating force, the automatic setting device for reading out and storing the contents of the storage ( 23) lifting device. The method of claim 12, And said memory device is formed as an electronic, magnetic or bar code-memory device. The method according to any one of claims 1 to 13, Lifting device, characterized in that the cargo holding device (10) is formed as a lifting table.

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