WO2010023208A1

WO2010023208A1 - Handling device, particularly for packaging machines

Info

Publication number: WO2010023208A1
Application number: PCT/EP2009/060949
Authority: WO
Inventors: Francesco Maria Bernardi
Original assignee: Dp S.R.L.
Priority date: 2008-08-27
Filing date: 2009-08-25
Publication date: 2010-03-04
Also published as: ITBO20080525A1

Abstract

A handling device, particularly for packaging machines, which comprises at least one crank (2), at least one linkage (3) and at least one slider (4), which form substantially a pusher crank system. The slider (4) is suitable to entrain products to be packaged and to deliver them to a subsequent processing station at the top dead center of the crank system. The handling device comprises at least one driving unit for the crank system, which defines, for the movable end (2a) of the crank (2), a path that oscillates about the top dead center according to any predefined breadth value.

Description

HANDLING DEVICE, PARTICULARLY FOR PACKAGING

MACHINES

Technical Field

The present invention relates to a handling device, particularly for packaging machines. Background Art

In the field of packaging machines, for various kinds of articles, and particularly for rolls of paper of the tissue type (for example absorbent paper or toilet paper), machines are widespread which are capable of packing a predefined number of rolls in order to define the packaging unit that is usually sold to the end consumer.

According to a known embodiment, these machines have first of all devices for feeding and handling the rolls, which are thus arranged in a group that has the desired configuration, typically consisting of multiple rows and/or layers of rolls.

Once the rolls have been arranged in the desired configuration, they are delivered to a compartment that is formed in a receiving station provided in the main body of the machine.

The compartment consists of two side walls, a back wall and a lower plane; said lower plane consists of a component, known as lifting pan, that can move along a vertical direction. This movement makes it possible to lift the group of products from the insertion station into an upper compartment consisting of the teeth of the traction device, which handles the rollers while the actual wrapping cycle is performed on them. During lifting, the products strike a sheet of film that is interposed between the lower compartment and the upper compartment, initiating the wrapping of said product.

Once the batch of products has been delivered into the upper compartment, the lifting pan returns to the initial position to receive a new batch of products and begin a new wrapping cycle. According to known constructive solutions, the reciprocating motion of the lifting unit is achieved by means of a pusher crank system.

More precisely, according to a first constructive solution, the crank turns at a constant speed, entraining with it the linkage and the pan, performing at each wrapping cycle a full rotation about its own axis. If it is necessary to process a different roll format, an assigned operator must replace the crank with one that has a different length, suitable for the dimensions of the new rolls.

It is evident that this solution has the drawback of requiring a machine downtime from the production line in order to replace the crank, in addition to requiring the purchase and storage of a plurality of components of various sizes.

These drawbacks are overcome at least partially by a second constructive solution, which resorts to a brushless motor that makes it possible to reverse the direction of rotation of the crank. Such crank is made to oscillate about the intermediate position between the top dead center and the bottom dead center, and the breadth of the angle that is traced can be varied at will in order to adapt to the different roll formats.

Further, the brushless motor makes it possible to change the rule of motion of the crank, and therefore of the pan, in order to optimize the wrapping cycle.

Even this constructive solution, however, is not free from drawbacks.

If particularly short cycle times are needed, as is required ever more often in the current production landscape, the motor struggles to adapt to the speeds that are imposed, while the mechanical stresses that act on the moving parts become excessive.

More specifically, the moment of motion reversal is particularly critical: the motion reversal times of the motor are excessively long with respect to the needs, while the required decelerations are too high for the mechanical strength of the components involved. Disclosure of the Invention

The aim of the present invention is to solve the problems described above, providing a handling device that ensures efficient and regular operation without subjecting the involved members to excessive stress. Within this aim, an object of the invention is to provide a handling device that makes it possible to adapt simply and rapidly to the changes of format of the product to be handled.

Another object of the invention is to provide a handling device that can be obtained easily starting from commonly commercially available elements and materials.

Another object of the invention is to provide a handling device that has modest costs and is safe in application.

This aim and these objects, and others that will become better apparent hereinafter, are achieved by a handling device, particularly for packaging machines, which comprises at least one crank, at least one linkage and at least one slider, so as to form substantially a pusher crank system, said slider being suitable to entrain products to be packaged and to deliver them to a subsequent processing station at the top dead center of said crank system, characterized in that it comprises at least one driving unit for said crank system, which defines, for the movable end of said crank, a path that oscillates about the top dead center according to any predefined breadth value.

Brief description of the Drawings

Further characteristics and advantages of the invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment of the handling device according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figures 1 to 13 are schematic front elevation views of the operation of the handling device according to the invention. Ways of carrying out the Invention

With reference to the Figures, the handling device according to the invention, generally designated by the reference numeral 1, comprises at least one crank 2, at least one linkage 3 and at least one slider 4, which form substantially a pusher crank system, whose particularities and operating principle are known from technical reference literature.

The slider 4 is capable of entraining products to be packaged to a subsequent processing station; more precisely, these products are delivered at the top dead center of the crank system (i.e., when the crank 2, the linkage 3 and the slider 4 are in the mutual configuration shown in Figures 4 and 10).

According to the invention, the handling device 1 comprises at least one driving unit for the crank system: said driving unit defines, for the movable end 2a of the crank 2, a path that oscillates about the top dead center according to any predefined breadth value.

It should be noted immediately that the products cited above are for example rolls of paper of the tissue type, i.e., toilet paper, absorbent paper or the like, which are to be wrapped in a film of a material such as plastic or paper. Reference shall therefore be made to this type of product in the continuation of the present description, but the application (which in any case lies within the protective scope defined by the present description) of the handling device 1 according to the invention to different types of products is not excluded. According to a constructive solution of particular interest in practice, which is cited here by way of non-limiting description of the application of the invention, the rolls feed a packaging machine, which comprises a first transfer and sorting apparatus capable of providing the desired grouping of rolls. This apparatus delivers the rolls thus sorted to a receiving compartment, from which they are subsequently sent, by virtue of the handling device 1, to the subsequent processing station, which is provided with the elements assigned to their packaging. This packaging provides for the wrapping of the rolls in a sheet of plastic film and for subsequent folding and finally heat-sealing of the flaps of film.

In order to allow handling and support of the products, the slider 4 substantially consists of a pan 5, which is arranged at right angles to its direction of translational motion.

Advantageously, the handling device 1 according to the invention comprises an assembly for controlling and managing the driving unit; said assembly makes it possible to control and reprogram the predefined breadth value and the speed profile of the crank 2, which are set by the driving unit.

The advantages ensured by this possibility of reprogramming the movement parameters are described in greater detail in the continuation of the present description.

More particularly, the driving unit is a motor of the type of brushless motors, which is functionally associated with the crank 2.

The operation of the handling device according to the invention is as follows. At the beginning of a working cycle of the pan 5, said pan is arranged below the roll receiving compartment, constituting its base, and the components of the pusher crank system are arranged in the configuration shown in Figure 1.

As a consequence of the rotation of the crank 2 (as in Figures 2 and 3), the pan 5 rises until it arrives at the top dead center (Figure 4), where the rolls are delivered to the subsequent processing station.

As becomes more evident from the accompanying figures, while the pan 5 moves from the receiving compartment to the subsequent processing station the crank 2 traces, in its rotation about its own axis, which passes substantially through its fixed end 2b, an angle that is equal to half of the predefined breadth value cited above.

The crank 2, pushed by the brushless motor, subsequently continues its stroke (as in Figures 4 and 5) until it returns the pan 5 to the initial configuration (thus tracing, as a whole, an angle that is equal to the predefined breadth value).

In this configuration, as can be seen from Figure 7, while the pan 5 has returned to the initial configuration, completing the working cycle that corresponds to the handling of a group of rolls and return, the crank 2 has moved to a position that is symmetrical with respect to the initial one. At the subsequent instant, the motor and the crank 2 reverse their direction of motion in order to retrace in the opposite direction the path traced in the previous cycle (as shown in Figures 8 to 13), thus making the pan 5 perform a second working cycle.

It appears therefore evident that in the handling device 1 according to the invention, by virtue of the choice to make the crank 2 perform an oscillation about the top dead center, reversal of the motion of the pan 5 does not correspond, as instead occurs in known devices, to the instant of reversal of the motion of the motor: reversal of the motion of the pan 5 is simply ensured by the mechanism of the crank system. This leads to an advantageous reduction of the mechanical stresses at the most critical point of the cycle: delivery of the rolls to the subsequent station in fact requires maximum precision and short execution times (also in view of the constraints set by the steps that occur downstream), with considerable stresses on the involved elements. The handling device 1 according to the invention therefore has a safer operation, with which no intense stresses are associated, since it does not require the motor (and therefore the crank 2 and the linkage 3) to perform a sudden deceleration, until motion is stopped and reversed, at the most critical point of the cycle.

The presence of the control and management assembly further makes it possible to program a variable rule of motion for the rotation rate of the crank 2, in order to optimize the cycle at the delivery of the rolls to the subsequent station.

As noted, the motor produces reversal of the motion of the pan 5 when it approaches and reaches the receiving compartment; this is a less stressed step of the cycle, and it is therefore possible to impart the necessary deceleration, with consequent motion stop and reversal, to the crank 2; of course, also in this case it is possible to study a rule of motion that is gentler and less stressful for the elements involved.

As is evident from what has been described so far, in order to adapt the handling device 1 according to the invention to a variation of the format of the rolls it is sufficient to change the stroke of the pan 5 by acting, by means of the control and management assembly, on the trajectory of the crank 2, imparting a different value of the breadth of the oscillation angle.

Finally, it should be noted that in order to deal with the requirement of particularly high productivities it is possible to make the crank 2 perform a full rotation about its own axis, without the subsequent reversal of motion but continuing with an angular velocity whose orientation and, possibly, whose value are constant. A path is thus substantially defined in which the value of the breadth of the oscillation angle is equal to infinity (and therefore is nonetheless within the protective scope defined herein).

This solution is possible by providing for example a variable coupling between the linkage 3 and the crank 2, so as to provide a purely mechanical modification of the stroke of the pan 5.

In practice it has been found that the handling device according to the invention fully achieves the intended aim, since the presence of a driving unit for the crank system comprised within the device makes it possible to define, for the movable end of the crank, a path that oscillates about the top dead center, according to any predefined breadth value, thus ensuring efficient and regular operation without excessively stressing the involved members. The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may further be replaced with other technically equivalent elements. In the exemplary embodiments shown, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments.

Moreover, it is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer.

In practice, the materials used, as well as the dimensions, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. BO2008A000525 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A handling device, particularly for packaging machines, comprising at least one crank (2), at least one linkage (3) and at least one slider (4), so as to form substantially a pusher crank system, said slider (4) being suitable to entrain products to be packaged and to deliver them to a subsequent processing station at the top dead center of said crank system, characterized in that it comprises at least one driving unit for said crank system, which defines, for the movable end (2a) of said crank (2), a path that oscillates about the top dead center according to any predefined breadth value.

2. The handling device according to claim 1 , characterized in that said slider (4) substantially consists of a pan (5), which is arranged at a right angle to its direction of translational motion and is suitable to support products to be packaged.

3. The handling device according to claim 1, characterized in that it comprises an assembly for the control and management of said driving unit, said predefined breadth value and the speed profile of said crank (2), set by said driving unit, being controllable and reprogrammable by means of said control and management unit.

4. The handling device according to one or more of the preceding claims, characterized in that said driving unit is a motor of the type of brushless motors, functionally associated with said crank (2).