METHOD FOR WRAPPING PLASTIC FILM ON A LOAD AND WRAPPING MACHINE

Abstract

A method and wrapping machine for wrapping a plastic film web from at least one roll on a load with a wrapping machine, wherein the location of the at least one roll of plastic film web in relation to at least the height of the load to be wrapped is detected and monitored during wrapping, one or a plurality of points or locations along the height of the load to be wrapped are preset before starting of the wrapping, at which preset points or locations and/or between said preset points or locations the wrapping characteristics are changed during wrapping.

Claims

1-12. (canceled)

13: A method for wrapping a load with a plastic film web from a roll using a wrapping machine, said method comprising: during wrapping of the plastic film web on the load, monitoring the plastic film web in relation to a height of the load being wrapped, wherein a location along the height of the load is preset before starting of the wrapping, said preset location being above a bottom of the load and below a top of the load; and responsive to detecting that the plastic film web reaches the preset location along the height of the load, changing at least one wrapping characteristic of the wrapping of the plastic film web on the load.

14: The method of claim 13, wherein said at least one wrapping characteristic includes at least one of: a wrapping height, a number of plastic film web layers wrapped, a tension of the plastic film web, a wrapping speed, an amount of overlap of subsequent wrapping rounds, and an overlap tension.

15: The method of claim 14, which includes enabling an operator to set said preset location using a user interface prior to starting of the wrapping of the load.

16: The method of claim 14, which includes enabling an operator to set said at least one wrapping characteristic prior to starting of the wrapping of the load.

17: The method of claim 13, which includes enabling an operator to set said preset location using a user interface prior to starting of the wrapping of the load.

18: The method of claim 13, which includes enabling an operator to set said at least one wrapping characteristic prior to starting of the wrapping of the load.

19: The method of claim 13, wherein the wrapping includes rotating the plastic film around the load while the load is stationary.

20: The method of claim 13, which includes pre-stretching the plastic film web before wrapping the plastic film web around the load.

21: A wrapping machine for wrapping a plastic film web from a roll on a load, said wrapping machine comprising: a first device for detecting and monitoring the location of the roll of plastic film web in relation to a height of the load to be wrapped during wrapping; a second device for defining at least one preset location along the height of the load above a bottom of the load and below a top of the load; and a third device for changing at least one wrapping characteristic responsive to the plastic film web reaching the preset location along the height of the load.

22: The wrapping machine of claim 21, wherein said devices comprise at least one processor and at least one memory including computer program code, wherein the program code is configured to, when executed by the at least one processor, cause the at least one processor to control the motors of the wrapping machine moving the roll of plastic film web in relation to the load to be wrapped and a motor for feeding the plastic film web.

23: The wrapping machine of claim 22, wherein the computer program code is configured, when executed by the at least one processor, to cause the at least one processor to control the at least one wrapping characteristic during the wrapping so that at least one of a wrapping height changes, a number of wrapped plastic film web layers changes, a tension of the plastic film web changes wrapping speed changes, an amount of overlap of subsequent wrapping rounds changes, and an overlap changes.

24: The wrapping machine of claim 21, wherein the first device for detecting and monitoring the location of the roll of plastic film web in relation to the height of the load to be wrapped during wrapping comprises an encoder arranged in connection of a motor moving the roll of plastic film in a vertical direction and a photocell.

25: The wrapping machine of claim 21, which includes an automatic control system for controlling the wrapping machine and said devices with a user interface for setting the preset location.

26: The wrapping machine of claim 21, which includes an automatic control system for controlling the wrapping machine and said devices with a user interface for setting the wrapping characteristic.

27: The wrapping machine of claim 21, which includes a device for rotating the one roll of plastic film web around a stationary load.

28: The wrapping machine of claim 21, which includes a device for pre-stretching the plastic film.

Description

[0022] In the following an exemplifying embodiment of the invention is discussed in greater detail in the sense of example and with reference to accompanying drawings, where,

[0023] FIG. 1 shows schematically an embodiment of a wrapping machine utilizing the present invention, and

[0024] FIG. 2 shows schematically the principle of controlling and setting of the wrapping process of the invention.

[0025] FIG. 1 shows schematically a wrapping machine 1, which comprises a frame 2, a circular guide 3 connected to the frame vertically adjustably, and a carrier 4 for roll of plastic film web 9, which carrier is movable along the circular guide.

[0026] Load to be wrapped is brought, usually on a suitable pallet, under the circular guide 3 in the area inside the circular guide with a suitable forklift or conveyer belt passing though the wrapping machine 1, for example. Once the wrapping process is started, the circular guide 3 is first lowered downwards until the load to be wrapped cuts a light beam from a photocell connected to the circular guide, at which moment the vertical position of the circular guide is registered and used to determine the height of the load to be wrapped by an automatic control system controlling the wrapping machine and its wrapping process.

[0027] The wrapping machine 1 also comprises a user interface 5, which is used to input data, or select corresponding setting, relating to the type of pallet into the automatic control system on which the load to be wrapped in located, so that the automatic control system knows the level from which the wrapping is to be started or at which is to be ended at the lower end of the load to be wrapped.

[0028] The vertical position of the circular guide 3, and thus also the vertical location of the roll of plastic film web 9 located in a carrier 4 connected to the circular guide, is defined and monitored with an encoder arranged in the motor 6 moving the circular guide vertically along the frame 2. The encoder forwards the location data to the automatic control system of the wrapping machine 1.

[0029] Another encoder is arranger in the motor 7 which rotates the carrier 4 along the circular guide 3, which also forwards data of the location of the carrier 4 on the circular guide to the automatic control system of the wrapping machine 1.

[0030] Based on the data obtained from the two encoders, the automatic control system, which comprises suitable data processing means and devices, such as data processors or processing units, memories and computer program codes, determines and follows the location of the roll of plastic film web 9 in relation to the load to be wrapped.

[0031] The automatic control system also controls a motor 8 for feeding the plastic film web from the carrier 4, which motor is located in the carrier, so that the feeding of the plastic film web is adjusted accordingly with the changes in the other wrapping characteristics during wrapping.

[0032] The user interface 5 also allows the operator of the wrapping machine 1 to input different settings and changes to the automatic control system of the wrapping machine before the wrapping process is stated, so that suitable wrapping for different kinds of loads to be wrapped can be obtained. This is discussed in more detail below in connection to FIG. 2.

[0033] FIG. 2 shows schematically the principle of controlling and setting of the wrapping process of the invention.

[0034] At the start of the setting process the user sets the points or locations along the height of the load to be wrapped, which are shown in FIG. 2 as numbered circles. The location of points can be defined as distance from the pallet top surface or from the top of the load to be wrapped, for example. The amount of the set points or locations may be between 1-5, preferably 3-5.

[0035] Once the points are set, the user defines wrapping characteristics to be applied at the set points or between the set points. The wrapping characteristics may include: [0036] wrapping height, [0037] number of plastic film web layers wrapped, [0038] tension of the plastic film web, [0039] wrapping speed, [0040] amount of overlap of subsequent wrapping rounds, and/or [0041] overlap tension.

[0042] Once the set setting of points and wrapping characteristics is done, the user starts the actual wrapping process, which is the carried out by the wrapping machine, such as one shown in FIG. 1, in accordance with the settings.

[0043] The user may freely set the points and locations along the height of the load to be wrapped as well as the related wrapping characteristics, which allows the same wrapping machine to be used in multitude of different wrapping modes and ways without the need to make changes to the programmable logic, i.e. the automatic control system, controlling the wrapping machine.

[0044] The selected settings may also be saved into the automatic control system of the wrapping machine, so that the saved settings can be retrieved to be used again.

[0045] The changes to the wrapping characteristics during the wrapping process are carried out by the automatic control system of the wrapping machine based on the location information of the roll of plastic film web and controlling of the motors moving the roll of plastic film web.

[0046] The specific exemplifying embodiments of the invention shown in figures and discussed above should not be construed as limiting. A person skilled in the art can amend and modify the embodiments in many evident ways within the scope of the attached claims. Thus the invention is not limited merely to the embodiments described above.