The invention concerns self-propelled wrapping machines designed to wrap extensible plastic film around a load.

Self-propelled wrapping machines, also referred to as self-propelled wrapping robots, are machines used for wrapping with film loads having variable shapes and sizes and in productions in limited amounts, typically in environments or places where fixed or static wrapping machines cannot be used because of the overall dimensions and/or available spaces. The loads generally are formed by pallets over which a plurality of products and/or objects are arranged, more or less regularly stacked, also with different sizes and formats. In other cases, the wrapping, normally for protective purposes, directly concerns the product, which is generally large-sized.

Self-propelled wrapping machines are known that include a carriage or trolley provided with at least one rear drive wheel and a front guiding device comprising a pair of steering wheels that are generally guided by a steering. The steering can be operated via a guiding bar or shaft by an operator in order to manually drive the machine in a manoeuvring configuration, or by a feeler element capable of following the external outline of the load in a working configuration, in which the self-propelled machine rotates autonomously around the load in order to wrap it with the film. The rear drive wheel is rotated by a respective rotary electric motor, which is connected to said rear drive wheel directly or by means of a mechanical speed reducer.

A vertical column is fixed to the carriage and a plastic film unwinding or dispensing apparatus is mobile along the vertical column and houses a film reel and plurality of rollers for unwinding and in case pre-stretching or elongating the film.

The unwinding apparatus is moved up and down along the vertical column by a rotary electric motor by suitable motion transmission means.

The combination of the linear alternating movement of unwinding apparatus along the vertical column and the rotation of the self-propelled machine around the load allows the film to be wrapped around the load so as to form a series of strips or bands intertwined in a helical fashion. The plastic film is wrapped to completely bind up the load on all its sides.

In order to pre-stretch or elongate the plastic film, the unwinding apparatus can be provided with a pair of pre-stretching rollers comprising a slow roller and a fast roller, respectively positioned upstream and downstream with reference to a movement of the film. By appropriately adjusting the difference between the rotational speeds of the two pre- stretching rollers, it is possible to stretch or elongate by a defined amount, according to a settled pre- stretch or elongation percentage, the film exiting from the unwinding apparatus before it is wrapped around the load.

In order to operate the pre-stretching rollers the unwinding apparatus comprises a rotary electric motor for rotating one of the two pre- stretching rollers, which acts as the drive roller (typically the fast roller), and, via a mechanical transmission assembly, the other prestretching roller, which acts as the driven roller (typically the slow roller).

Unwinding devices are also known which comprise two rotary electric motors, each of which rotates a respective pre- stretching roller.

The known self-propelled wrapping machines also comprise a plurality of sensors suitable to detect operating and alarm conditions of the machine, and a control unit, which is configured to receive and process signals from said sensors and controls the operation of the machine, namely the operation of the various electric motors.

A control panel is provided that is connected to the control unit to act as operating interface and to allow an operator to interact with the machine, for example in order to enter specific operating parameters, select wrapping programs, etc.

In order to electrically power the electric motors that move the machine and its different apparatuses, the sensors, the control unit and the control panel, the known wrapping machines are equipped with one or more electric batteries capable of supplying the necessary electrical current.

The electric batteries are housed within an internal compartment of carriage, which also allows reaching and accessing, for example for maintenance works, some of the above described mechanical and/or electrical components of the machine , for example parts of the front guiding device, the electric motor that move the drive wheel, etc.

The compartment is closed by a covering casing, generally made of plastic material, which is a single body or is formed by a plurality of parts, which can be positioned on, or removed from, the carriage and can be reversibly fixed to the carriage by suitable hooking means. Nevertheless this covering casing, especially if it consists of several parts, is inconvenient to be mounted or dismounted and requires one or more skilled operators and a not brief stop of the wrapping machine.

An object of the present invention is to improve the known self-propelled wrapping machines for wrapping loads with plastic film.

Another object is to provide a self-propelled wrapping machine that allow a quick and easy access to an internal compartment of the machine for maintenance works.

A further object is to provide a self-propelled wrapping machine having a simple and robust structure.

These objects and others are achieved by a self-propelled wrapping machine according to claim 1.

The self-propelled wrapping machine according to the invention suitable for wrapping a load with film of plastic material comprises a self-propelled carriage having an internal compartment and comprising frame means and a covering casing having a front portion that is rotatably connected to the frame means and movable between an opened position, to allow access to the compartment, and a closed position, to prevent access to the compartment. The carriage further comprises moving means associated with the covering casing and suitable to at least maintain the covering casing firmly in the opened position.

The moving means comprise at least one gas spring, which connects the covering casing to frame means and is suitable to maintain the covering casing firmly in the opened position and to adjust a rotation speed of the covering casing from the opened position to the closed position and vice versa, and/or at least one flexible element that connects the covering casing to frame means in order to prevent the covering casing from rotating further away from the frame means in the opened position.

The covering casing that is rotatably connected to frame means of carriage allows a quick and safe access to the internal compartment. In fact, the moving means facilitate and support the lifting of covering casing up to the opened position and maintain the covering casing firmly in the opened position, preventing it spontaneous closing , for example due to gravity or to a casual collision or push. The closing of the internal compartment by the operator that lower the covering casing is also quick and safe, as the moving means slow down and regulate the movement of covering casing from the opened position to the closed position. In particular, the moving means allow adjusting the rotation speed of the covering casing until the covering casing abuts a supporting plane of frame means, so as to prevent impacts or contact between the edges of walls of the covering casing and the supporting plane.

The invention can be better understood and implemented with reference to the attached drawings, which illustrate some exemplifying and non-limiting embodiments thereof, in which: figure 1 is a plan view of the self-propelled wrapping machine of the invention, wherein some parts have been removed in order to better show an internal compartment of the carriage and a covering casing in opened position; figure 2 is a section of the self-propelled wrapping machine according to line II-II of figure 1; figure 3 is a scaled-down side view of the self-propelled wrapping machine of figure 1 with the covering casing in closed position; figure 4 is a scaled-down plan view of the self-propelled wrapping machine of figure 3; figure 5 is an enlarged section of the self-propelled wrapping machine according to line V-V of figure 4.

With reference to figures 1 to 5, a self-propelled wrapping machine 1 according to the invention is partially shown that is mobile around a load to wrap the load with a plastic film. In particular, for the sake of simplicity, the figures only illustrate the self-propelled carriage 2 of the self-propelled wrapping machine 1 provided with a pair of rear wheels 22, of which at least one is a drive wheel, and without the front guiding device, which includes the steering wheels and the steering, operated by means of a guiding bar or shaft by an operator, in order to manually move the machine in a manoeuvring configuration, or by means of a feeler element capable of following the external outline of the load in a working configuration, in which the self-propelled machine rotates autonomously around the load to wrap it with the film.

The self-propelled wrapping machine 1 illustrated in the figures also does not have the vertical column along which the plastic film unwinding or dispensing apparatus moves.

The self-propelled wrapping machine 1 comprises a self-propelled carriage 2 having an internal compartment 3 for housing, by way of example, an electric battery 50 of the machine 1. More precisely, inside the compartment 3 for example technological systems of the machine 1 are positioned that allow function and efficient operation of the machine, such as the power supply system, the electronic control system, and/or the motor system, which, for example, allows movement of the machine 1.

The carriage 2 also comprises a covering casing 4 having a front portion 4a that is rotatably connected to frame means 21. The covering casing 4 is also movable between an opened position A, which allows access to the compartment 3, and a closed position B, which prevents access to the compartment 3.

The carriage 2 comprises moving means 5, which are connected to the covering casing 4 and are suitable to at least maintain the covering casing 4 firmly in the opened position A.

The covering casing 4 is substantially shell shaped in order to enclose and contain the compartment 3. The covering casing 4 has a front wall 41, an upper wall 42, two side walls 43, and a rear wall 44.

The covering casing 4 is fixed to frame means 21 at a lower edge of the front wall 41, and is also rotatable about a rotation axis X. The axis X is substantially horizontal and orthogonal to the side walls 43.

In the closed position B, the front wall 41, side walls 43, and rear wall 44 of the covering casing 4 substantially abut the supporting plane 21a of frame means 21 of carriage 2.

In the opened position A, the covering casing 4 is rotated of an angle a about the rotation axis X, so that front wall 41, side walls 43, and rear wall 44 are spaced apart from the supporting plane 21a.

When the covering casing 4 is in the opened position A, the angle a is, for example, substantially equal to 90°. The angle a is the angle between the supporting plane 21 and the upper wall 42 of the covering casing 4.

The moving means 5 comprise at least one gas spring 6, which connects the covering casing 4 to the frame means 21 and is suitable to maintain the covering casing 4 firmly in the opened position A and to adjust a rotation speed of the covering casing 4 from the opened position A to the closed position B and vice versa.

The gas spring 6, of a known type, comprise a cylinder containing a pressurized gas, such as nitrogen, inside which a piston slides. An end of the cylinder is connected for example to the covering casing 4, while a free end of the piston rod is connected to the frame means 21. In particular, the gas spring 6 is suitable to allow a safe and easy movement of the covering casing 4. In particular, the gas spring 6 also allows slowing a movement of the covering casing between opened position A and the closed position B.

The moving means 5 also comprise, or alternatively comprise, a flexible element 7 that connects the covering casing 4 to frame means 21 in order to prevent the covering casing 4 from rotating further away from frame means 21 when it is in the opened position A, this causing an anomalous tensile stress to the gas spring 6 that could lead to a damage thereof. The flexible element 7 has an elongated shape and has and end that is connected to the frame means 21 and the opposite end that is connected to the covering casing 4. The flexible element 7 comprises, for example, a flat belt or band made of plastic or metal material. The flexible element 7 and the gas spring 6 are positioned side by side.

The covering casing 4 comprises a supporting frame 10 that is fixed to the upper wall 42 and/or to the front wall 41 is provided with a connection end 10a that is rotatably connected to a supporting element 12 of frame means 21.

The supporting element 12 comprises a fork support fixed to the supporting plane 21a of frame means 21 of carriage 2. The supporting element 12 is also connected to the connection end 10a of supporting frame 10 by means of a rotation pivot 11. In particular, the covering casing 4 is rotatably associated with the body of carriage 2 by means of the rotation pivot 11.

The operation of the self-propelled wrapping machine 1 according to the invention can be understood from the following description.

An operator who needs to access the compartment 3 lifts the covering casing 4 from its closed position B to its opened position A. The gas spring 6 facilitates and supports the lifting of the covering casing 4 up to the opened position A and maintains the covering casing 4 firmly in the opened position A, preventing the spontaneous descent of the covering casing, for example due to gravity, or to casual collisions or pushes.

The flexible element 7 that connects the covering casing 4 to the frame means 21, on the other hand, prevents the operator from rotating the covering casing 4 to much (beyond the opened position A) or the cover from further rotating due to casual pushes, thus protecting the integrity and functionality of gas spring 6.

With the covering casing 4 firmly maintained in the opened position A by the gas spring 6, the operator can access the compartment 3 and act on, and/or replace, components of the technological systems of the machine 1, such as the electric batteries 50.

When the operator no longer requires access to the compartment 3, he/she lowers the covering casing 4 from the opened position A to the closed position B. During this movement, the gas spring 6 slows and adjusts the rotation speed of the covering casing 4 until it abuts the supporting plane 21a of the frame means 21, in order to prevent impacts or contacts between the edges of the walls of the covering casing and the supporting plane 21a. Objects of the invention are therefore achieved. In particular, the covering casing 4 that is rotatable alternatively allows or prevents access to the compartment 3 where, in particular, the batteries of the machine 1 are housed.

Moreover, the moving means 5 allow maintaining the covering casing 4 firmly in the opened position A, in order to provide a safe and reliable access to the compartment 3 to the operator, and facilitating and controlling the rotation of the covering casing between the opened position A and the closed position B, and vice versa, in particular by regulating its rotation speed.