An unwinding apparatus for a self-propelled wrapping machine (100) mobile around a load for wrapping the latter with a plastic material film (50), comprises frame means (2) for supporting a reel (60) of film (50); roller means (11, 12, 13, 14, 15) for unwinding and pre-stretching the film (50); at least one folding element (3) mobile along a narrowing trajectory (R) for abutting a first longitudinal edge (50a) of the film (50) and pushing the latter towards a second longitudinal edge (50b) of the film (50) so as to reduce a strip width (L) of film (50) exiting the apparatus (1); driving means (10) for moving the folding element (3) and comprising moving means (4; 104) supporting the folding element (3) and mobile along the narrowing trajectory (R); electric actuator means (5) connected to, and driving, the moving means (4; 104); a control unit (20) connected to the driving means (10) for adjusting a displacement and/or a moving direction of the moving means (4; 104); the wrapping apparatus (1) also comprises first sensor means (30; 130) coupled to the moving means (4; 104) for continuously detecting and measuring at least a displacement of the moving means and sending a related signal to the control unit (20) so as to control and adjust during wrapping the load a position of folding element (3) along the narrowing trajectory (R) and thus the strip width (L) of film (50).

The present invention relates to a stretch wrapping machine and a device for stretch wrapping products which must breathe during their storage and transport process. The stretch wrapping machine comprises a rotating base (1) configured to support the palletized load and a fixed column (2) next to the rotating base (1) comprising a first reel (3) of an extendable sheet (5), said first reel (3) being movable along said column (2). The stretch wrapping machine additionally comprises a second reel (4) of a non-extendable sheet (6), said second reel (4) being movable along said column (2). As a result of the transpiration features of the extendable sheet (5), the preservation of the load will be optimal. The method of the invention comprises stretch wrapping the load with the extendable sheet (5) to subsequently stretch wrap the load with a layer formed on the inside by the non-extendable sheet (6) and on the outside by the extendable sheet (5).

The present invention provides a method and apparatus for dispensing a predetermined fixed amount of pre-stretched packaging material based upon load girth. A non-rotating ring carries a belt driven by a motor. A packaging material dispenser is mounted on a rotating ring, and the rotating ring may include a pulley that connects to the band, such that the rotating ring is driven by the drive belt. Based upon the girth of the load to be wrapped, an amount of pre-stretched packaging material to be dispensed for each revolution made by the rotating ring is determined. Good wrapping performance in terms of load containment (wrap force) and optimum packaging material use is obtained by dispensing a length of pre-stretched packaging material that is between approximately 90% and approximately 120% of load girth.; Once the amount of packaging material to be dispensed per revolution is determined, a ratio of rotating ring drive to final pre-stretch surface speed (i.e., number of pre-stretch roller revolution/ rotating ring rotation) can be set and mechanically controlled. Thus, for each revolution of the rotating ring and dispenser, a predetermined fixed amount of packaging material is dispensed and wrapped around the load. In an alternative embodiment, the ratio is electronically controlled.

A wrapping machine and a method for wrapping a plastic foil web (F) around an object. A gripping and cutting device (11) is connected to a lifting frame (3) supporting a circular guide track of a foil dispenser (6) so as to be vertically movable with the lifting frame. In the method, the wrapping action is started from a freely chosen point relative to the vertical direction of the object and ended correspondingly at a freely chosen point relative to the vertical direction of the object.

The invention relates to a crinkling device comprising a slide rod (16), to which a second crinkling element (15) is fastened. The slide rod is guided in a frame (2) so as to be movable in a substantially vertical direction between a lower position (L), in which the second crinkling element (15) is out of contact with the lower edge (4) of a foil web (1), and an upper position (U), in which the second crinkling element (15) deflects the lower edge (4) of the foil web (1) upwards so as to crinkle it. The slide rod returns to the lower position (L) when not exposed to a force acting in the upward direction. The device further comprises first coupling means (17¹, 18¹) for forming a releasable coupling between the slide rod (16) and a first drive element portion (8) when the drive element (7) is running in a first direction (11) to move the second crinkling element (15) to the upper position (U). Second coupling means (17², 18²) are provided to form a releasable coupling between the slide rod (16) and a second drive element portion (9) when the drive element (7) is running in a second direction (12) to move the second crinkling element (15) to the upper position (U). By driving the drive element (7) in the first running direction (11), the foil web (1) can only be crinkled from its lower edge (4). By driving the drive element (7) in the second running direction (12), the foil web (1) can be crinkled optionally either from the upper edge (3) by a first crinkling element (14) without crinkling the lower edge (4) or from the upper edge (3) and the lower edge (4) simultaneously.

An apparatus for wrapping a pallet load (L) with a wrapping film applied selectively as a film rope (R) or as a film sheet (F) includes means (28) to support the load (L) in an elevated position. A rotary arm (32) supported above the load (L) is arranged to be rotatably driven. An upright member (50) depending from the rotary arm (32) is spaced outwardly from the load (L). A carriage (60) is arranged to be upwardly and downwardly driven along the upright member (50). A dispenser on the carriage dispenses the wrapper as a rope (R) or as a sheet (F). A guide (200), which comprises a lever (206, 210) and a hook (204) on the lever, is moveable among extended, partly retracted, and fully retracted positions. In the extended position, the guide (200) guides the rope (R) across the respective corners of the load (L). In the partly or fully retracted position, the guide does not interfere with driving the carriage (60) along the upright member (50).