FIELD OF THE INVENTION

The present invention concerns an apparatus for supporting and moving a metal sheet or such like, which can be used to feed the metal sheet to a subsequent work machine, in particular a machine that works the metal sheet by molding or shearing to obtain metal products such as sheared thin metal sheets or suchlike.

BACKGROUND OF THE INVENTION

As is known, the shearing of thin metal sheets is a process able to create parts with the most disparate uses. Among the most important uses of sheared thin metal sheets, for example, we can cite electric motors which nowadays, thanks to increasing electric mobility, lead the way in an increasingly impressive market demand.

The machines that shear the metal sheet - fed by a continuous strip of metal sheet - are in fact presses that act on shearing dies: the dies shear the metal sheet, creating sub-parts with the desired shape, called thin metal sheets for simplicity.

Presses nowadays work at high speed, that is, they are capable of shearing up to over 1000-2000 times per minute.

There are apparatuses for supporting and moving sheets which are able to feed the sheet into these shearing presses, or other machinery. Substantially, in these apparatuses the metal sheet, at least in the movement or feed step, is held or clamped between the opposite rollers, so that following their rotation in opposite directions it can advance toward the press.

An example of a roller apparatus to advance sheets is described in document CN 107262555 A.

The functioning of these apparatuses therefore consists in advancing the metal sheet to feed the press in the appropriate measure, that is, in the size of the thin metal sheet to be sheared; this measure is variable, therefore they have to release the sheet because once the press has been fed, it has to shear.

During the shearing step there are centering means which carry out small but precise corrections by moving the metal sheet appropriately so that it is centered, according to a given tolerance.

During this centering and also during shearing, in practice these steps more or less coincide, the metal sheet must be released from the movement and support apparatus, therefore this apparatus must provide an action to release the sheet in addition to the feeding and clamping action.

A typical functioning cycle of a known support and movement apparatus 14 is indicated purely by way of illustration in fig. 1.

The apparatus 14 comprises two opposite rollers 11 and 12 between which a metal sheet 13 is disposed, and which can rotate moved by means of motors.

Fig. 1 also shows a graph showing the time t in seconds (s) on the x axis and on the y axis the force F applied on the sheet expressed in Newton (N), as a function of the various functioning steps F1-F5.

In step Fl the upper roller 11 is distanced from the sheet 13, while the lower roller 12 supports the sheet 13.

In step F2 the rollers 11 and 12 are pressed against the sheet 13 by a force F, for example applied to the upper roller 12.

In step F3 the rollers are made to rotate in opposite directions by means of motors so as to advance the sheet 13 in a direction A; this step is called the feed step. During this step F3, a maximum force Fmax is applied on the sheet 13.

In step F4, the upper roller 11 is distanced from the sheet 13, which is unconstrained, that is, free to be able to be moved by the shearing press.

Step F5 is like step Fl, the cycle repeats itself.

The apparatus 14 must be perfectly synchronized with the shearing press as it must release the sheet 13 according to step F4 exactly when the press shears.

The times of steps F2 and F4 are dead times, that is, times necessary to drive the roller 11 so that it presses the sheet 13 or not, but they must be as short as possible since they increase the cycle time unnecessarily, compromising productivity.

In these steps F2 and F4 it is possible that there is a significant problem of acoustic pollution, or noise, made by the support and movement apparatus. In particular, moving the roller 11 during steps F2 and F4 at high speed produces a noise and therefore a wasted acoustic energy as well as a considerable acoustic pollution. Furthermore, known support and movement apparatuses also have a problem connected to rebound phenomena, that is, in particular during step F2 the roller 11 moves rapidly toward the sheet 13 and the inevitable impact of the roller 11 on the sheet 13 causes the roller to rebound.

During step F4 the roller 11 rapidly moves away from the sheet 13 to stop against an end-of-travel element and the inevitable impact on the end-of-travel element causes the roller to rebound.

The rebounds cause various problems, including for example less friction between rollers and metal sheet, therefore less ability to draw the sheet, slowing down steps F2 and F4, and noise.

There is therefore a need to perfect an apparatus for supporting and moving a metal sheet, to be used in particular in a machine for working thin metal sheet, able to obtain sheared metal sheets, which can overcome at least one of the disadvantages of the state of the art.

In particular, one purpose of the present invention is to provide an apparatus for supporting and moving a metal sheet, or suchlike, which limits the phenomena of acoustic pollution, and therefore noise, during normal functioning steps, usable in particular in machines for working metal sheet by shearing.

Another purpose of the present invention is to provide an apparatus for supporting and moving a metal sheet, or suchlike, which is able to drastically reduce the above rebound phenomena of the roller on the sheet.

Another purpose of the present invention is to provide an apparatus for supporting and moving a metal sheet, or suchlike, which allows to increase the productivity and duration of the work machine on which it is installed.

Another purpose of the present invention is to perfect an effective method of supporting and moving a metal sheet, or suchlike.

Another purpose of the present invention is to provide a machine for working a metal sheet which is highly productive and durable.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

In accordance with the above purposes, the present invention concerns an apparatus for supporting and moving a metal sheet, or suchlike, comprising a pair of rollers, wherein at least one of the rollers is connected to means for rotating around an axis.

According to one aspect of the invention, at least one roller is associated with a support structure which can be deformed elastically at least in the direction of the axis of rotation of the roller by means of flexible elements and at least two actuators, associated respectively with a first support of a first end of the roller and a second support of a second end of the roller. The actuators are configured to independently raise or lower each end allowing the roller to come into contact with, or to detach from, the metal sheet first with one end and subsequently with the other end.

Advantageously, the present apparatus for supporting and moving a metal sheet, or suchlike, since it allows a gradual contact and/or detachment of the roller with/from the metal sheet, limits the phenomena of acoustic pollution, and therefore noise, during the normal functioning steps, and can be used effectively in machines for working the metal sheet by means of shearing, in particular.

Thanks to this graduality of contact and detachment, the present apparatus drastically reduces the rebound phenomena of the roller on the metal sheet, typical of known systems.

The present apparatus also allows to increase the productivity and duration of the work machine on which it is installed.

The rollers can comprise at least a first roller for pressing the metal sheet and at least a second roller for supporting the metal sheet; the support structure is preferably associated with the pressing roller.

In some embodiments, the present apparatus can comprise first flexible elements located in the proximity of the ends of the roller and directed substantially parallel to the direction of feed of the metal sheet.

In particular, for each end of the roller, a first pair of first flexible elements can be positioned in front of the roller, with respect to the direction of feed of the metal sheet, and a second pair of first flexible elements can be positioned behind the roller.

The present apparatus can comprise second flexible elements directed in a direction substantially orthogonal to the direction of feed of the metal sheet.

In particular, the present apparatus can comprise a first pair of second flexible elements positioned in front of the roller, with respect to the direction of feed of the metal sheet, and a second pair of second flexible elements positioned behind the roller.

The actuator devices can be associated with the supports by means of corresponding rods able to allow the movement of the supports and therefore of the ends of the roller in defined raising or lowering directions.

In the present apparatus, each actuator device can comprise at least two opposite actuators able to act on a mobile part located between the actuators and associated with the rod.

Each actuator device can comprise one or more damping elements positioned between the actuators and the fixed parts of the apparatus.

Another purpose of the invention is a method to support and move a metal sheet or suchlike by means of an apparatus as defined above, comprising at least one step of gradual pressing of the metal sheet carried out by the movement of at least one end of a roller toward the metal sheet and gradual contact therewith, and then a subsequent contact of the other end of the roller, and at least one step of detaching the roller from the metal sheet carried out by means of gradual detachment of at least one end of the roller from the metal sheet and then the subsequent detachment of the other end of the roller.

The present method can provide that in this step of gradual pressing and/or in this step of gradual detachment the actuator devices are driven staggered, that is, with a reciprocal time delay.

Another purpose of the invention is a machine for working a metal sheet, comprising an apparatus for supporting and moving a metal sheet and an apparatus for working the metal sheet, in particular a pressing, shearing or similar apparatus located downstream of the support and movement apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a schematic view of a known sequence of the movement of a metal sheet in a machine for shearing the metal sheet;

- fig. 2 is a schematic three-dimensional view of an apparatus for supporting and moving a metal sheet according to the present invention;

- fig. 3 is another three-dimensional view of the present apparatus;

- figs. 4a and 4b schematically show the functioning principle of the present apparatus in an operating step;

- fig. 5 is a longitudinal section view of a linear actuator usable in the present apparatus;

- figs. 6a and 6b show by way of example the functioning of the linear actuator of fig. 8;

- figs. 7a and 7b schematically show two successive movements of an operating step of the present apparatus;

- figs. 8a, 8b, 8c schematically show an operating sequence of the present apparatus;

- fig. 9 is a schematic view of a functioning sequence of the present apparatus for supporting and moving a metal sheet in a machine for shearing the metal sheet.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be combined or incorporated into other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

We will now refer in detail to the various embodiments of the invention, of which one or more examples are shown in the attached drawings by way of a non-limiting illustration. The phraseology and terminology used here is also for the purposes of providing non-limiting examples.

With reference to the attached drawings, see for example fig. 2, an apparatus 10 for supporting and moving a metal sheet 13, or suchlike, according to the present invention, comprises at least one pair of rollers 11 and 12.

The metal sheet 13 or in general a sheet of metal or other similar or comparable material that can be moved by means of the apparatus 10 can have a thickness comprised between about 0.05mm and about 3mm.

At least one of the rollers 11, 12 is connected to means 15 for rotation around a corresponding axis of rotation Bl, B2, so that the metal sheet 13 is moved in the direction A following the rotation of at least one of the rollers 11, 12 put in contact with the metal sheet 13.

In particular, such means 15 can comprise for example an electric motor connected to one or both of the rollers 11, 12. In this example, the rotation means

15 are connected for example to the roller 12, which can therefore be made to rotate by means of such means 15. The other roller 11 could be provided with its own rotation means, or it could be connected to the means 15 by means of motion transmission means, or it could even be an idle roller, therefore dragged into rotation by the metal sheet 13 when it is made to advance by means of the roller 12. The roller 11 comprises a first axis of rotation Bl while the roller 12 comprises a second axis of rotation B2. The axes Bl and B2 are substantially parallel and are substantially orthogonal to the direction A of feed of the metal sheet 13.

In the present apparatus 10, at least one of the rollers 11, 12 in fig. 2, for example the roller 11, is associated with a support structure 18 that can be deformed elastically at least in the direction of the axis B 1 of rotation of the roller 11, by means of a plurality of flexible elements 19a, 19b, 19c, 19d, 20a, 20b, 20c, 20d and a plurality of actuator devices 21, 22, or at least two actuator devices 21, 22. At least a first actuator device 21 is associated with a support 23 of a first end

16 of the roller 11 and at least a second actuator device 22 is associated with a support 24 of a second end 17 of the roller 11.

In these supports 23 and 24 there can be housed bearings for supporting the shaft of the roller 11 or suchlike. The supports 23 and 24 are constrained to the support structure 18 and this in turn is constrained to the ground, or to a fixed part of the apparatus 10, not shown.

The actuator devices 21, 22 are configured to independently raise or lower each end 16, 17 of the roller 11 allowing, thanks to the consequent elastic deformation of the support structure 18, the roller 11 to come into contact with, or to detach from, the metal sheet 13 first with one end 16, 17 and subsequently with the other end 17, 16.

The roller 12 is essentially a roller for supporting the metal sheet 13, while the roller 11 is a roller for pressing the metal sheet 13. Preferably, the support structure 18 is associated with the pressing roller 11.

The present apparatus 10 can comprise first flexible elements 19a, 19b, 19c, 19d located in the proximity of the ends 16, 17 of the roller 11 and directed substantially parallel to the direction A of feed of the metal sheet 13.

In particular, for each end 16, 17 of the roller 11, the present apparatus comprises a first pair of first flexible elements 19a and 19b positioned in front of the roller 11, with respect to the direction A of feed of the metal sheet 13, and a second pair of first flexible elements 19c and 19d positioned behind the roller 11.

The first flexible elements 19a, 19b, 19c, 19d can be for example bending springs which allow the support structure 18 to perform small displacements in the directions VI and V2, see also fig. 3. The direction VI is substantially a vertical direction along which a first end 16 of the roller 11 can move. The direction V2 is substantially a vertical direction along which a second end 17 of the roller 11 can move.

Preferably, the first flexible elements 19a, 19b, 19c, 19d are independent of each other and allow the support structure 18 and therefore the ends 16, 17 of the roller 11 to move independently in the direction VI or in the direction V2, so as to allow the roller 11 to gradually move toward the metal sheet 13.

The first flexible elements 19a, 19b, 19c, 19d can also allow the support structure 18 to be constrained or connected to the fixed part of the apparatus 10.

The present apparatus 10 can also be equipped with second flexible elements 20a, 20b (not visible), 20c, 20d directed in a direction substantially orthogonal to the direction A of feed of the metal sheet 13.

In particular, a first pair of second flexible elements 20a and 20b can be located in front of the roller 11 and a second pair of second flexible elements 20c and 20d can be located behind the roller 11.

The second flexible elements 20a, 20b, 20c, 20d can be bending springs able to decouple the movement of the support structure 18 first in VI and then in V2, or vice versa.

The second flexible elements 20a, 20b, 20c, 20d substantially allow the supports 23, 24 to be displaced respectively in direction VI, V2 with a motion substantially directed only in the directions VI, V2. These directions VI, V2 are ultimately raising or lowering directions of the supports 23, 24 and therefore of the ends 16, 17 of the roller 11.

As stated, the first flexible elements 19a, 19b, 19c, 19d and the second flexible elements 20a, 20b, 20c, 20d can be configured as bending springs, that is, flexible shaped foils, therefore being very light and suitable for high dynamic applications.

Furthermore, the flexible elements 19a, 19b, 19c, 19d, 20a, 20b, 20c, 20d can be deformed elastically with a displacement of the order of a few tenths of a millimeter, for example between about 0.09mm and about 1mm, which is what is required in this type of applications. This allows to exclude more complex mechanisms, for example of the hinge type, which in addition to requiring more frequent maintenance and constant lubrication would increase the noise of the apparatus 10.

The actuator devices 21 and 22 act on the supports 23 and 24 by means of corresponding rods 25 and 26 directed in the raising or lowering directions VI, V2 of the supports. The rods 25 and 26 can be associated with the supports 23, 24 by means of corresponding housing seatings 27 and 28. The rods 25 and 26 could be threaded rods able to engage in corresponding counter threads or nut screws made in the seatings 27 and 28. The attached drawings show an actuator device 21 or 22 for each end 16 or 17 of the roller 11, therefore for each of the supports 23 or 24. However, it would be possible to provide a plurality of actuator devices for each end 16 or 17 of the roller 11, preferably in equal numbers for each end 16 or 17 of the roller 11.

The actuator device 22, see also fig. 4a and fig. 4b, acts in the direction V2 so as to, for example, raise the end 17 of the roller 11. In this example, the roller 11 rests on the metal sheet 13 by means of a zone close to the end 16, see fig. 4a.

At this point, the actuator device 21, see fig. 4b, acts in the direction VI in order to raise the zone of the roller 11 and therefore the end 16 which was in contact with the metal sheet 13.

In this way, substantially, the present apparatus 10 has detached the roller 11 from the metal sheet 13 in a gradual and controlled manner, similarly to step F4 of fig. 1.

The bending of the roller 11 to allow the raising or lowering of the corresponding ends 16 and 17 occurs substantially as a result of an elastic deformation of the support structure 18, at least along the axis Bl.

Fig. 5 shows an example of an actuator device 21 that can be used in the present apparatus 10. The following description can refer in the same way to the actuator device 22.

The actuator device 21 can comprise two opposite actuators 29 and 30 able to act on a mobile part 31 located between the actuators 29 and 30, so as to move it in the direction VI in one sense or the other. The actuators 29 and 30 can comprise solenoids, for example, suitably excited or de-excited and cooperating with the mobile part 31 , in this case for example a plate or metal anchor. The mobile part 31 is integral with the rod 25. The rod 25, as stated, can be threaded and able to engage in a threaded seating 27.

The rod 25 therefore transmits the force of the actuators 29 and 30 to the support structure 18.

The actuator device 21 can comprise damping elements 32 and 33 positioned between the actuators 29 and 30 and the fixed parts 34 and 35 of the apparatus 10. The damping elements 32 and 33 can be discs, plates or suchlike, made of elastomeric material.

The damping elements 32 and 33 have high damping power and can be stackable in order to increase the damping effect when it is necessary to increase the damping, or the opposite when it is to be reduced.

The actuator 29 is driven when the mobile part 31 is to be raised in the direction VI. The actuator 30 is driven when the mobile part 31 is to be lowered in the direction V 1.

In particular, see for example fig. 6a and fig. 6b, when the actuator 29 is driven, the mobile part is displaced upward in the direction V 1 until it hits against the actuator 29.

The impact will also very slightly displace the actuator 29 which will compress the damping elements 32. The damping elements 32 will dampen the vibrations. The actuator device 21 could be constrained to the fixed part 34 by means of attachment elements 36, such as screws or suchlike, which are free to move together with the actuator 29, as indicated by the comparison of figs. 6a and 6b, to allow deformation of the damping elements 32.

As stated, the actuator device 22 can also be made in a manner completely similar to the actuator device 21, therefore it can comprise the actuators 37 and 38, comprising for example solenoids or suchlike, acting on the rod 26 by means of a mobile plate, see the diagram of fig. 8a. Consider for example fig. 7a as an initial functioning condition of the apparatus 10, in which the roller 11 is slightly pressed against the metal sheet 13 by the force F: by driving the actuators 30 and 38 of fig. 8, the rods 25 and 26 thrust the roller 11 against the metal sheet 13 in such a way as to increase the force F up to a value F’, fig. 7b. In this way, steps F2 and F3 are carried out, which determine the clamping of the metal sheet 13 by the rollers 11 and 12. The work of the forces is very low, since the roller 11 practically does not move even if the force acting on it is high.

Thanks to the support structure 18, which deforms elastically, the step F2 is performed substantially as in the schematic sequence of figs. 8a, 8b and 8c. In a first step, the actuator 38 thrusts the support 24 and therefore the end 17 of the roller 11 against the metal sheet 13. In a subsequent moment, the actuator 30 will thrust the support 23 and therefore the end 16 of the roller 11 against the metal sheet 13, fig. 8c. In this way, a gradual movement of the roller 11 toward the metal sheet 13 is obtained. On the contrary, when the roller 11 has to be moved away from the metal sheet 13 in the directions VI and V2, the actuators 30 and 38 will be deactivated and the actuators 29 and 37 will be driven.

By means of the present apparatus 10, as schematically shown in the sequence of fig. 9, in step F2 the actuator 38 thrusts on the metal sheet 13 with a force F’ which increases over time along the ramp LI, while the actuator 30 thrusts with a force F’ which increases over time along the ramp L2, therefore the actuator 30 acts on the metal sheet 13 staggered and delayed by the time 1 with respect to the actuator 38. During the step F4, on the contrary, first the actuator 30 and then the actuator 38 are deactivated, this time staggered by the time so that also the step of releasing the force exerted on the metal sheet 13 is also gradual.

The delays <j)l and (j)2 can be varied, extended or reduced in order to mitigate the noise and impacts during the step of pressing or releasing the metal sheet 13.

Step F5 is the one that allows to move the roller 11 away from the metal sheet 13, by means of the actuators 29 and 37. These actuators 29 and 37 work not against the clamping force F’ but only against the small pre-loading force F, therefore the work completed or the energy used is also minimal on this occasion.

We wish to point out that minimum energy means increasing performances in terms of productivity and noise reduction or noise pollution, and increase in duration.

The actuators 29 and 37 can also be driven staggered by or a different staggering, according to requirements.

Both in step F2 and in step F5, that is, the steps of driving first the actuators 30 and 38 and then the actuators 29 and 37, the roller 11 will be subjected to accelerations and decelerations until it stops, against the metal sheet 13 or against an end-of-travel element.

Preferably, these accelerations and decelerations are very intense, so that the steps F2 and F5 are as short as possible. Therefore, it is preferable that the actuator devices 21 and 22 are equipped with the damping elements 32 and 33 described above.

A machine 40 for working a metal sheet 13, therefore, can provide the support and movement apparatus 10 and, downstream, an apparatus 39 for working the metal sheet 13, in particular a pressing, shearing or similar apparatus 39.

It is clear that modifications and/or additions of parts may be made to the apparatus for supporting and moving a metal sheet, or suchlike, as described heretofore, without departing from the field and scope of the present invention as defined by the claims.

In the following claims, the sole purpose of the references in brackets is to facilitate reading: they must not be considered as restrictive factors with regard to the field of protection claimed in the specific claims.