Patent Description:
As it is well known in this specific technical field, there are various apparatuses capable of performing the automated cutting of sheets of material according to a pre-set cutting pattern, the material to be cut being for instance hide, a fabric, a non-woven fabric, a synthetic material and the like. The types of sheet material to be cut are indeed the most varied, even in the same technical field. The clothing, accessory and footwear industries all use for instance multiple materials such as hide, non-woven fabrics, synthetic materials. These materials, while having evident differences in their manufacture and consistency, nevertheless have the common denominator of being in sheets and of being subjected to cutting operations.

There are machines equipped with a conveyor belt capable of moving the sheet to be cut inside a cutting chamber, which is generally closed at the top and laterally on at least two sides, said cutting chamber being equipped with at least one movable cutting unit for cutting the sheet, whereas the cut portions are conveyed by the conveyor belt out of the cutting chamber towards an unloading area.

There are also simpler machines, the so-called cutting tables or benches, which do not have a closed cutting chamber (and possibly do not have a conveyor belt that feeds the sheet) but only a worktable (possibly a fixed one) whereon the material to be cut is arranged. Such a machine is known from <CIT>. According to some known solutions, on the opposite major sides of the cutting table, respective rails are arranged for the sliding of carriages that move at least one crosspiece or arm extended transversely, which supports a movable cutting unit to cut the sheet arranged on the worktable. Once the cutting has been performed, the arm is moved in order to clear the work area and the operator can collect the cut portions, possibly while the cutting head cuts the sheet at another area of the worktable.

The aforementioned machines are very flexible and easily allow cutting samples and small productions of hides, synthetic materials and fabrics of all kinds.

However, a first problem of the above machines is linked to the arrangement of the material to be cut on the worktable, said material generally having dimensions that are greater than the worktable, so that there is always exceeding material that initially cannot be arranged on said worktable. In other words, the overall dimensions of the guides and of the carriages for moving the arm do not allow an easy arrangement of the exceeding material. In some known solutions, only one guide system is used, which supports the arm at the second major side of the worktable that is opposite the first side at which the operator acts; however, in this solution there is the need to create, at said second side, a cradle that forms the suitable seat for receiving the material to be cut that is wound in a roll, which the operator may unwind from time to time. Such a solution considerably complicates the structure of the machine and the positioning of the sheet, since the structure of the worktable must be suitably shaped so as to form said cradle, where the material roll is arranged. Moreover, the arrangement of the material into the cradle is difficult since it implies the rolling up of said material and the insertion thereof into the cradle, which is distant from the work area.

Other even more widespread solutions have guides that allow the arm to slide on both major sides of the worktable and provide forming, in addition to the above cradle, a slot at the side opposite that of the cradle into which the exceeding material is inserted, thus making the positioning operation even more complicated. Furthermore, the presence of the slot and of the further guide move the operator away from the machine, so that the operator does not work easily.

There are solutions where the guides are arranged on the minor sides of the table, so that the arm slides along these minor sides; however, the presence of the guides along the sides is an encumbrance for the operator, said machines requiring in any case advanced safety systems, as illustrated in the following paragraph.

Another problem, even more felt, is due to the safety of these machines because, since there is no cutting chamber enclosing the cutting units and the movable arm, a contact with these cutting units or with the moving arm supporting them is much more likely, with very dangerous consequences for operators. For this reason, there is the need to adopt additional safety measures.

The technical problem of the present invention is to provide a cutting machine having structural and functional features so as to allow overcoming the above-mentioned limitations and drawbacks which still affect the known solutions, in particular capable of offering an increased safety for the operator.

The solution idea at the basis of the present invention is to make a cutting machine equipped with a protective screen close to the ends of the movable arm, said screen being shaped so as to avoid the operator's direct contact with the cutting units. The protective screen is capable of translating integrally with the arm and is tilting with respect thereto, so that, when it hits against an obstacle, in particular when its lower portion that is farthest from the arm hits an obstacle, it may rotate about the hinging axis, thus absorbing the collision and allowing a control unit to stop the operation of the machine on time and in total safety. A collision against the upper end of the screen, i.e. closer to the hinging point, is instead absorbed by an additional protection element that is for instance hinged at the lower end of the screen and is capable of performing a pivoting movement towards the edge of the screen, also said movement activating the safety stop.

The machine of the present invention is also equipped with other safety systems, such as photocells, making the cutting machine herein described extremely safe.

Based on this solution idea, the above technical problem is solved by a machine for cutting sheet material comprising a worktable adapted to provide a support plane for a sheet of material to be cut, at least one cutting unit adapted to cut the sheet arranged on the worktable, at least one arm that is arranged at least partially above the worktable and is adapted to support the cutting unit, supporting means of the arm, which is supported so as to be movable along a sliding direction, and at least one protective screen connected to a support, in particular connected to the arm at an end portion of said arm, said protective screen being adapted to translate in the sliding direction due to the movement of the arm, the machine being characterized in that the protective screen is hinged to its support structure (i.e., preferably, to the arm) at a hinging point, so as to be tilting with respect to the arm, said protective screen being adapted to perform an at least partial rotation with respect to said hinging point, in particular when it hits an obstacle along the sliding direction.

More particularly, the invention comprises the following additional and optional features, taken individually or in combination if needed.

According to the present invention, the machine is comprising a control unit configured to stop the movement of the arm based on the rotational movement of the protective screen.

According to an aspect of the present invention, the protective screen may have a body configured to cover at least partially the cutting unit, at least when it is observed from a direction that is substantially orthogonal to the sliding direction.

According to an aspect of the present invention, the protective screen may be directly connected to the arm. Other embodiments in which said screen is connected to the arm through a support are also possible, even if it is preferable to connect said screen directly to the arm.

According to another aspect of the present invention, the protective screen may be arranged at an end of the arm.

According to another aspect of the present invention, the end of the arm may comprise a connection projecting portion which the protective screen is hinged to.

Furthermore, the machine of the present invention may preferably comprise two protective screens arranged at opposite sides of the worktable, i.e. opposite along a direction that is substantially orthogonal to the sliding direction.

Furthermore, the machine of the present invention may comprise at last one pair of arrays of photocells configured to move integrally with the arm, said photocells being arranged at least along a vertical direction that is substantially orthogonal to the worktable and being configured to detect the presence of an object therebetween.

According to an aspect of the present invention, at least one of the arrays of photocells may be arranged on the protective screen and may be adapted to move integrally with the protective screen.

According to an aspect of the present invention, the control unit may be configured to stop the operation of the machine when there is no alignment between opposite arrays of photocells due to the rotation of the protective screen about the hinging point, for instance as a consequence of the collision with an operator.

Alternatively or in combination, the machine may comprise a sensor that is operatively connected to the control unit and configured to detect the rotation of the protective screen, wherein the control unit is configured to stop the operation of the machine when the sensor detects the rotation of the protective screen.

According to another aspect of the present invention, the machine may comprise an additional protection element connected to the protective screen, the additional protection element having a body connected to said protective screen and being configured to perform a relative movement towards/away from the protective screen. Preferably, there is at least one free end of said additional protection element that is capable of performing a pivoting movement.

In particular, the body of the additional protection element may be hinged to the protective screen and configured to perform a pivoting movement towards/away from said protective screen.

Alternatively, the additional protection element may be translating with respect to the protective screen.

According to another aspect of the present invention, the body of the additional protection element may be configured so as to extend along an edge side portion of the protective screen, in particular an edge portion extending (in the rest position) in a direction that is substantially orthogonal to the sliding direction, the protective screen and the additional protection element being connected to each other and configured so that the rotational movement of one of the protective screen and the additional protection element is triggered based on the position in which a collision occurs.

The additional protection elements are arranged along the sides of the protective screen that are opposite with respect to the sliding direction.

According to another aspect of the present invention, the arrays of photocells may be arranged on additional protection elements that are connected to screens opposite along the longitudinal axis of the arm and are adapted to move integrally with said additional protection elements, the control unit being configured to stop the operation of the machine when there is no alignment between the opposite arrays of photocells due to the relative movement of one of the additional protection elements with respect to the screen (for instance a rotation about the hinging point), for instance due to a collision with an operator.

Furthermore, the machine may comprise a protection elastomeric element configured to cover, at least partially, the arm.

According to yet another aspect of the present invention, the protective screen may be connected to the arm through a pin element that is housed in a suitable seat at said arm.

Finally, the support means of the arm may be in the form of a crosspiece support structure that is kept hanging over the worktable by at least one support upright that extends from the worktable, the worktable may be a fixed plane and free of encumbrances along at least two parallel sides of greater extension, and the arm may be cantilevered supported on the worktable through said crosspiece.

The features and advantages of the cutting machine according to the invention will become apparent from the following description of an embodiment thereof, given by way of non-limiting example with reference to the accompanying drawings.

With reference to those figures, and in particular to <FIG>, a cutting machine according to the present invention is globally and schematically indicated with the reference number <NUM>.

It is worth noting that the figures represent schematic views and are not drawn to scale, but instead they are drawn so as to emphasize the important features of the invention. Moreover, in the figures, the different elements are depicted in a schematic manner, their shape varying depending on the application desired. It is also noted that in the figures the same reference numbers refer to elements that are identical in shape or function. Finally, particular features described in relation to an embodiment illustrated in a figure are also applicable to the other embodiments illustrated in the other figures.

The positional references used in the present description, comprising indications such as lower or upper, above or below, or similar phrases, are referred to the operating configuration shown in the figures, and in no case should they be assigned a limiting meaning. In any case, said references, when referred to the components of the machine of the present invention, are used in practice by a skilled person.

To facilitate the following description of the machine <NUM>, as illustrated in <FIG>, two orthogonal directions corresponding to orthogonal movements of a cutting unit of the machine <NUM> are identified by way of example: a Y direction and a X direction. In particular, as it will be illustrated in greater detail hereinafter, the X direction is also indicated as sliding direction of an arm of the machine <NUM>.

In its most general form, the machine <NUM> is adapted to process, and in particular is adapted to automatically cut, hides, leather, synthetic materials and the like. Still more particularly, the machine <NUM> is adapted to automatically cut sheets of foldable or flexible material, for instance fabrics for clothing and hide goods, footwear items, automotive and furnishing articles, or non-woven fabrics, hides, synthetic materials and the like.

In the context of the present invention, the term "sheet" indicates any element of any shape and material, having a substantially two-dimensional size and a certain thickness (generally reduced), which is to be cut through the machine <NUM>.

The machine <NUM> is a numerical control machine comprising a control unit C, for instance including suitable memory units, suitably programmed and arranged for the management and automatic control thereof. The control unit C may be for instance a computerized unit that is integrated in or external to the machine <NUM> and operatively connected thereto. Furthermore, the control unit may be a single control unit or may comprise a plurality of local units. The control unit C is thus capable of controlling the machine <NUM> to obtain the automated cutting of sheet material.

The machine <NUM> of the present invention is a so-called cutting bench and comprises a worktable <NUM> adapted to provide a support plane or work surface a for a sheet of material to be cut. The worktable <NUM> preferably has a quadrangular plan (still more preferably substantially rectangular) and at least one cutting unit or cutting head <NUM> carried by at least one arm or crosspiece <NUM> acts thereon.

In an embodiment of the present invention, the worktable <NUM> is a fixed plane, even if, in other embodiments, said worktable may be equipped with a conveyor belt (not illustrated in the figures) for moving the material arranged thereon.

In case of a rectangular-shaped worktable <NUM>, as illustrated in the figures, the Y direction (transversal direction of the worktable) is parallel to its minor sides and the X direction is parallel to its major sides. As previously indicated, the X direction is also called sliding direction of the arm <NUM>, which therefore, in an embodiment of the present invention, slides along the major sides of the worktable <NUM>. For the purposes of the present invention, however, nothing prevents the arm <NUM> from sliding along the minor sides of the worktable <NUM>, and therefore the sliding direction from being the Y direction, the present invention not being limited by a particular sliding direction of the arm <NUM>.

In general, the term worktable <NUM> indicates the structure supporting the sheet of material to be cut, said worktable being provided with at least two opposite sides of greater extension and with at least two opposite sides of minor extension (preferably rectangular or at least defining a rectangular work surface), and being a plane having a certain thickness, the term side thus indicating a side edge portion of the worktable.

Like in the conventional cutting benches, the machine <NUM> is equipped with a base <NUM>, for instance box-shaped, which is the support for the worktable <NUM> and possibly encloses mechanical and electronic elements to assist the operation of the machine <NUM>.

More particularly, the machine <NUM> comprises at least one cutting unit <NUM> specifically arranged for cutting the sheet arranged on the worktable <NUM>, said cutting unit <NUM> not being limited to a particular type. By way of example, the cutting may occur through blade, laser, water jet, milling cutter or in any other suitable way, preferably through a blade.

According to an embodiment, illustrated in the figures, the machine <NUM> comprises a single cutting unit <NUM>, even if the present invention is not limited thereto, and the number of the cutting units may vary according to the needs and/or circumstances.

As previously noted, the machine <NUM> comprises at least one arm <NUM> that is at least partially arranged above (on the top of) the worktable <NUM> and is adapted to support the cutting unit <NUM>, which is movable on said arm <NUM>, in particular sliding along the longitudinal axis of said arm <NUM>, said longitudinal axis being parallel to the Y axis of <FIG> and <FIG>.

Specifically, in an embodiment, the movement of the cutting unit <NUM> is allowed thanks to the presence of a carriage <NUM>, which is translatable along the longitudinal extension of the arm <NUM>, i.e. along the Y axis, by means of first guides G1 arranged on a face of said arm <NUM>, for instance arranged on a lower face thereof facing the worktable <NUM>. In other words, the cutting unit <NUM> is supported by the carriage <NUM>, which acts as a support shelf for said cutting unit <NUM>.

In this way, according to the above embodiment, the movement system of the cutting unit <NUM> comprises the arm <NUM> and the carriage <NUM>, which define a kinematic structure for moving said cutting unit <NUM>. As mentioned above, the carriage <NUM> is preferably mounted below the arm <NUM> (which is why it is also referred to as "lower carriage", although other configurations are possible) and is translatable with respect thereto along the Y direction.

The arm <NUM> has a substantially parallelepiped shape with prevalent extension along the Y direction. As above indicated, it comprises the first guides G1 that are adapted to allow the relative movement of the carriage <NUM> that is mounted on sliding blocks <NUM>. In an embodiment, the first guides G1 are two (even if the present invention is not limited thereto) and two sliding blocks <NUM> aligned to each other are inserted on the guides. The movements are obtained through a recirculating ball screw/nut screw system.

Power and signal cables connecting the various elements of the kinematic structure are also provided, said cables being housed in a drag chain <NUM> that runs parallel to the arm <NUM> and forms, at the two opposite ends, a loop, as visible for instance in <FIG>.

Furthermore, support means <NUM> adapted to support the arm <NUM> over the worktable <NUM> are provided.

Hereinafter, an embodiment will be illustrated wherein, through the above support means <NUM>, the arm <NUM> is cantilevered supported and slides along the X direction. However, such an embodiment, though preferred, is merely indicative and the teachings of the present invention (i.e. the safety measures as below detailed) are not limited by the particular support and sliding configuration of said arm <NUM>.

In particular, in the non-limiting exemplifying embodiment of the figures, the arm <NUM> is cantilevered supported on the worktable <NUM> by means of the support means <NUM> and is movable along the sliding direction X.

Suitably, the support means <NUM> of the arm <NUM> are in the form of a crosspiece (or lintel) support structure, still indicated with the reference number <NUM>, which is kept hanging over the worktable <NUM> by at least one support element or upright 9a. More particularly, in an embodiment, the support upright 9a extends vertically from the worktable <NUM>, in particular at an edge peripheral portion of said worktable <NUM>. Still more particularly, the support upright 9a is arranged at one of the minor sides of the worktable <NUM>, as it will be described in detail below. In an embodiment, the crosspiece <NUM> is an extruded aluminum, even if other configurations are obviously possible and are within the scope of the present invention.

In an embodiment, there are two support uprights 9a arranged at two opposite sides of the worktable <NUM>, i.e. at opposite edges, defining in this way a support gantry comprising said two uprights and the upper crosspiece integral thereto, from which the arm <NUM> cantilevered projects on the worktable <NUM>. In other words, the support uprights 9a allow the support crosspiece <NUM> to remain hanging over the worktable <NUM> and connect it to said worktable <NUM>.

Obviously, the shape of the uprights 9a, represented with a vertical axis and projecting from the worktable <NUM>, as well as the specific shape of the crosspiece <NUM>, is only indicative and other suitable shapes may be used.

In the preferred embodiment illustrated in the figures, the worktable <NUM> is substantially rectangular-shaped (or at least defines a work area having two major sides and two minor sides) and the support uprights 9a are arranged at the minor sides of said worktable, so that the two major sides are totally free of encumbrances, i.e. no component for the support of the arm <NUM> is arranged at said sides, which are the sides which the exceeding material is projected from, said material being subsequently dragged onto the worktable <NUM>.

The support uprights 9a thus allow keeping the crosspiece <NUM> hanging over the worktable <NUM>, so that it is possible to form thereon the guides that allow the connection and the support of the arm <NUM>, which is cantilever supported. In this way, it is no longer necessary to support the arm <NUM> by means of guides integrated on the worktable <NUM> (in particular arranged at the major sides of the table, as instead occurs in the known solutions). Thanks to this hanging-crosspiece configuration, the worktable <NUM> is thus free of encumbrances along at least two parallel sides, in particular along the major sides thereof, which the exceeding material to be cut may freely project from, without the need to use the expedients described in connection to the prior art, such as for instance the formation of housing cradles.

In other words, the structure of the machine <NUM> has many advantages, in particular for rectangular worktables, due to the fact that the major sides are totally free of encumbrances, so that the exceeding material may freely hang from said sides and can be easily dragged onto the plane when it is to be cut. It is further noted that said sides free of encumbrances are the sides at which the operator acts, greatly simplifying the latter's work. Furthermore, thanks to the presence of the hanging crosspiece <NUM>, the operator may easily work on both free sides of the table.

In an embodiment, in order to facilitate the operator's work, the support uprights 9a are arranged closer to one end of the minor sides (i.e. the rear end according to the local reference system of the figures) with respect to the opposite end, so as to leave the major side connected to said opposite end even more free of encumbrances. In other words, with respect to a longitudinal axis of symmetry, parallel to the X axis, the support uprights 9a are moved more towards one of the two ends of the minor sides (without necessarily reaching this end), which is advantageous in case the crosspiece <NUM> also supports other components, such as for instance display screens and projectors, as it will be described below, leaving in this way more space for the operator.

Furthermore, as above mentioned and as better illustrated in <FIG>, the arm <NUM> is constrained to a carriage <NUM> that is sliding along at least one guide, preferably two guides (not illustrated in the figures), formed on the crosspiece <NUM>, said guides allowing the sliding in the sliding direction X of the carriage <NUM> and thus of the arm <NUM> constrained thereto. In other words, the arm <NUM> is thus connected to the support means <NUM> through the carriage <NUM>, which allows the movement of the arm <NUM> in the X direction.

As noted for the carriage <NUM>, the carriage <NUM> as well comprises sliding blocks <NUM> and is associated with the guide through said sliding blocks. In the preferred case of two guides, two sliding blocks <NUM> aligned to each other are inserted on the guides.

In an embodiment, the carriage <NUM> is arranged below the crosspiece <NUM>, i.e. it is constrained to a face thereof facing the worktable <NUM> and thus is arranged between said crosspiece <NUM> and the arm <NUM>. The carriages <NUM> and <NUM> are moved through suitable means controlled by the control unit C.

The management of the apparatus <NUM> by the user may occur, for instance, through a control panel <NUM>, equipped with screen and buttons, arranged for instance at the periphery of the worktable and operatively connected to the control unit C.

In an embodiment, the machine <NUM>, in particular the worktable <NUM>, is ideally divided into two work areas. In this way, while in a first area sheet portions are cut through the cutting unit <NUM>, in a second contiguous area the operator may collect material portions already cut, said areas being alternated during the operation of the machine <NUM>. It is thus possible to work in time masking, i.e. cutting and unloading take place in masked time, with greater efficiency and productivity; machines of this type are also called "commuters". This operation may be performed by a single cutting unit that is suitably controlled by the control unit C and moved from an area to the contiguous area, as well as by two cutting units that are suitably controlled by the control unit C.

Since the cutting unit <NUM>, as well as the arm <NUM> supporting it, are not enclosed in a closed cutting chamber, there is the need to equip the machine <NUM> with suitable safety measures, also considering the fact that, as above illustrated, the collection of cut portions may occur simultaneously to the cutting operation in a contiguous area of the worktable <NUM>.

With reference to <FIG> and to <FIG>, a first safety measure is the adoption of photocells <NUM> adapted to detect the presence of a user and thus to stop the machine <NUM> in case a dangerous situation is detected.

More particularly, the machine <NUM> comprises a plurality of photocells <NUM> at both opposite ends 4a and 4b of the arm <NUM> and arranged so as to move integrally therewith, said photocells <NUM> being configured to detect the presence of an object therebetween.

The photocells <NUM> are arranged on proper supports (for instance proper sticks) whereon they define an array of photocells, in particular a pair of arrays arranged on opposite sides of the worktable <NUM>, i.e. opposite along the longitudinal direction Y of the arm <NUM>, and are connected (directly or indirectly) to said arm <NUM> so as to move along therewith. In this way, each photocell arranged at a side of the worktable <NUM> has a corresponding photocell arranged at the opposite side and is aligned therewith, so as to suitably receive/send the light signal <NUM>' for detecting objects, as illustrated in <FIG> and in <FIG>.

Suitably, the array of photocells extends vertically (i.e. the photocells are arranged at least along the vertical direction that is substantially orthogonal to the worktable <NUM> and thus substantially orthogonal to the Y and X directions), so as to cover at least the entire vertical overall dimensions of the system made of the cutting unit <NUM> and the arm <NUM>, unlike what happens in the known solutions in which a single photocell per side is used. In other words, the photocells extend on a vertical plane that is orthogonal to the worktable <NUM>, thus defining, through the light signals, a predetermined vertical area within which objects can be detected.

In a preferred embodiment of the present invention, there are two arrays of photocells <NUM> at a side of the worktable <NUM> and two arrays of photocells <NUM> at the opposite side, the arrays of each side being arranged in opposite positions with respect to the arm <NUM>, so as to offer protection against the movement of said arm <NUM> in both directions along the X direction.

Suitably the photocells <NUM> are operatively connected to the control unit C, which is programmed to automatically control the movement of the arm <NUM> and the actuation of the cutting unit <NUM> according to the signal coming from said photocells. In particular, once the operator's presence (for instance the presence of the operator's hand) is detected, the photocells send a signal to the control unit C, which is suitably configured to stop the operation of the machine <NUM>.

Consequently, in its more general form, a cutting machine is provided which comprises a worktable <NUM>, a cutting unit <NUM> adapted to cut the sheet arranged on the worktable <NUM>, an arm <NUM> that is arranged at least partially above the worktable <NUM> and support means <NUM> of the arm, said machine being equipped with the above described photocells <NUM>, so as to provide safety to the operator.

In any case, the presence of the sole photocells, though being a very important safety element, is not always capable of ensuring total safety for the operator, as well as there is also the need to reduce the risks due to a collision with the supports of the photocells themselves.

Advantageously according to the present invention, in order to equip the machine <NUM> with further effective safety measures, it also comprises a protective screen <NUM> that is associated with the machine <NUM> close to at least one end 4a and/or 4b of the arm <NUM>.

This safety system may have an own dedicated support or, preferably, it is directly connected to the arm <NUM>, in particular at an end of said arm <NUM>, which thus acts as a support.

Preferably, there are two protective screens <NUM>, each arranged at a respective end of the arm <NUM>, i.e. opposite along the Y direction at opposite sides of the worktable <NUM>. Thus, the following description will refer hereinafter to the preferred, but not limiting, case of two opposite protective screens <NUM>.

In an embodiment of the present invention, the protective screen <NUM> is substantially rectangular-shaped, even if other shapes may obviously be used. In its more general form, the protective screen <NUM> comprises a lower side, an upper side and at least two sides that are opposite each other with respect to the sliding direction.

Furthermore, the protective screen <NUM> may be made of any suitable material, including metal materials and plastic materials.

The protective screen <NUM> has a body <NUM>' that is cantilevered extended, in particular it projects downwards, with respect to its support, and is configured to cover at least partially the cutting unit <NUM> when observed along the Y direction, i.e. when observed frontally, so as to avoid a direct contact between the cutting unit and the operator.

In particular, the protective screen <NUM>, more specifically the body <NUM>', extends in a vertical plane at a frontal portion of the machine <NUM> for the protection of an operator who operates at the major sides of the worktable <NUM>, i.e. it is connected to the frontal portion of the arm <NUM>. Still more particularly, the protective screen <NUM> extends substantially orthogonally to the worktable <NUM> at the major sides thereof.

In order to allow the correct arrangement of the material on the worktable <NUM>, the protective screen <NUM> is associated with the machine <NUM> so as to leave an empty space G' between itself and an edge of the worktable <NUM>, as illustrated in <FIG>. Furthermore, the protective screen <NUM> extends below the work surface α of the worktable <NUM>, so as to prevent dangerous situations for the user. In other words, the protective screen <NUM> extends from the arm <NUM> beyond the work surface α of the worktable <NUM>. As it will be noted hereinafter, the protective screen <NUM> also acts as a housing for the photocells <NUM>, its extension with respect to the work surface α allowing a suitable covering by said photocells <NUM>.

As previously mentioned, in a preferred embodiment of the present invention, the protective screen <NUM> is directly associated (in particular connected) to an end of the arm <NUM>.

More particularly, in an embodiment, the arm <NUM> comprises, at the ends thereof, a connection projecting portion 4p, which the protective screen <NUM> is connected to. Obviously, the arm <NUM> may also not comprise the connection projecting portion 4p, what matters for the purposes of the present invention is that the longitudinal extension (i.e. along the Y axis) of said arm <NUM> is as a whole such as to be greater than the corresponding extension of the worktable <NUM>, so as to project and to leave an empty space between the protective screen <NUM> and the worktable <NUM> (as previously illustrated) and prevent said protective screen <NUM> from hitting said worktable <NUM>. In any case, the actual longitudinal extension of the arm <NUM> is not a limiting feature of the present invention.

Suitably, the protective screen <NUM> is hinged to the arm <NUM> at a hinging point P, so as to be tilting with respect to said arm <NUM> about said hinging point P. In an embodiment, the hinging point P is at an end of the protective screen <NUM> (in particular the upper end of the screen), the opposite end extending beyond (below) the work surface α as previously described, even if the particular position of the hinging point is not a limiting feature of the present invention.

In this way, the protective screen <NUM> is adapted to be translated along the sliding direction X due to the movement of the arm <NUM> when obstacles are not hit. Advantageously, the protective screen <NUM> is also capable of performing a rotational motion with respect to the hinging point P when, during the sliding along the X direction, it hits an obstacle to the movement, for instance when a user is hit. The protective screen <NUM> is thus capable of performing a relative movement with respect to the arm <NUM>, said movement being in this case a partial rotational movement, as illustrated in <FIG>, <FIG> and in <FIG>, wherein the rotation axis is substantially parallel to the Y axis and thus parallel to the longitudinal axis of the arm <NUM>; in other words, the hinging point P lies on an axis that is coincident, or at least parallel, to the Y axis and about which the protective screen <NUM> performs the above-mentioned pivoting movement.

Consequently, since the protective screen <NUM> is not fixedly constrained to the arm <NUM> but is tilting, when it hits an obstacle (for instance an operator), it is apt to rotate with respect to the hinging point P, said rotation reducing the collision effect and further causing the stop of the operation of the machine <NUM>, as it will be illustrated herein below.

In particular, the protective screen <NUM> provides protection from collisions against the lower portion of said screen, i.e. the portion that is closest to the worktable <NUM> and thus the furthest from the arm <NUM>, said collisions causing the pivoting movement of the screen as above illustrated.

In order to protect the operator also from collisions against the opposite upper portion of the protective screen <NUM>, i.e. the portion that is closest to the arm <NUM>, in an embodiment of the present invention the protective screen <NUM> is equipped with an additional protection element <NUM> connected thereto. The operation of this additional protection element <NUM> is illustrated in <FIG>.

The additional protection element <NUM> comprises an elongated body <NUM>' (not limited to a particular shape) connected to the protective screen <NUM>. Preferably, two additional protection elements <NUM> are connected to the protective screen <NUM>, so as to be arranged along two opposite sides of said protective screen <NUM> (i.e., looking in a frontal position at the protective screen <NUM>, on both left and right sides). In other words, given a protective screen <NUM>, there are two additional protection elements <NUM> arranged along the sides thereof that are opposite with respect to the sliding direction X.

In an embodiment, the additional protection element <NUM> extends at least by the whole length of the vertical side of the protective screen <NUM> and is constrained to said screen, in particular to the lower portion the screen, at an end of the additional protection element, whereas an opposite end of said additional protection element is kept free. Obviously, this embodiment must not be intended as limiting of the present invention and other configurations are also possible.

As above mentioned, the connection point between the protective screen <NUM> and the additional protection element <NUM> may be for instance at the lower end of the protective screen <NUM>, i.e. the portion that is furthest from the arm <NUM>, allowing a relative rotation as below detailed. In any case, the particular shape, as well as the particular connection mode and position of the additional protection element <NUM> must not be intended as limiting of the scope of the present invention and other suitable configurations are also possible.

Suitably, the additional protection element <NUM> is not fixedly constrained but hinged to the protective screen <NUM> and may perform a partial rotation towards/away from the protective screen <NUM>, until it touches it. In particular, the additional protection element <NUM> is capable of performing a pivoting movement in which the free end thereof (i.e. the non-hinged end) moves at the upper portion of the protective screen <NUM>.

In other words, advantageously according the above embodiment, a collision against the upper portion of the protective screen <NUM> is absorbed by the additional protection element <NUM>, which is apt to perform a pivoting movement towards the protective screen <NUM>, in particular a pivoting movement in the upper portion thereof that is opposite the hinging point with said protective screen <NUM>.

In an embodiment, the protective screen <NUM> acts as a support for the arrays of photocells <NUM>, which thus move integrally with said protective screen <NUM>. The operation of the machine <NUM> is thus stopped based on the rotational movement of the protective screen <NUM>, since said rotational movement causes a loss of alignment between the photocells <NUM> that are opposite with respect to the longitudinal axis of the arm and arranged on opposite screens, with the consequent generation of the stop signal from the control unit C. Obviously, even other methods of generation of the stop signal are possible, such as for instance the presence of a sensor S, that is operatively connected to the control unit C, which is configured to detect the relative rotation of the protective screen <NUM> with respect to the arm <NUM> and to generate a signal towards the control unit as soon as said relative movement has been detected, said signal stopping the operation of the machine.

Still more particularly, four additional protection elements <NUM> are provided (two for each opposite screen) and the photocells <NUM> are housed on said additional protection elements <NUM>, which, performing the pivoting movement further to the collision, cause a misalignment between the photocells arranged on the opposite sides of the worktable <NUM> (or they cause the triggering of the sensor S as above described).

In an alternative embodiment, the stop of the operation of the machine <NUM> is caused by the pressure, by the additional protection element <NUM> during the rotation, of a safety switch, said switch being pressed between the body of the additional protection element <NUM> and the body of the protective screen <NUM>. Obviously, the particular stop mode of the operation of the machine <NUM> is not limiting of the scope of the present invention and other modes are also possible, what matters is that said stop occurs as a consequence of the collision, and thus as a consequence of the rotation of the protective screen <NUM> and/or the movement of the additional protection element <NUM>. In still another embodiment, it is possible to provide for the presence of an element that is projecting from the screen or from the additional protection element and configured to stop (cover) at least one ray of the photocells <NUM> during the movement of the screen and/or of the additional protection element, causing the stop of the machine; in this latter case the photocells are not integral with the screen (but for instance are integral with the arm <NUM>).

Safety for the operator is therefore provided by the combination of the protective screen <NUM> and of the additional protection element <NUM>.

In fact, if said additional protection element <NUM> were not present, a possible collision with the upper portion of the screen <NUM> would cause a harm to the operator, since the pivoting movement of said protective screen <NUM> about the hinging point with the arm <NUM> would not be suitably triggered. Therefore, according to the present invention, if a collision with the operator occurs with the upper portion of the protective screen <NUM>, then the additional protection element <NUM>, which is preferably hinged at the opposite lower portion, rotates and causes the emergency stop of the machine <NUM>.

If a possible collision with the operator occurs with the lower portion of the protective screen <NUM>, then the entire tilting protective screen <NUM> rotates and causes the emergency stop of the machine <NUM>, and in this case the additional protection element <NUM> rotates integrally with the protective screen <NUM>. Consequently, according to the height at which the collision occurs, one or the other protection intervenes, or even both.

In other words, in case the collision occurs near the hinging point P, the effect of the relative movement of the additional protection element <NUM> is predominant, whereas the effect of the rotation of the protective screen <NUM> becomes predominant by moving away from the hinging point P towards the opposite end.

It is therefore apparent that the aforementioned measures guarantee extreme safety for the operator.

In this way, there are safety measures aiming at covering any possible dangerous situation. In fact, summing up, it is worth protecting the user from three main sources of danger:.

As for point a), the rotating movement of the protective screen <NUM> offers the desired protection.

As for point b), the protection is offered by the additional protection element <NUM> (that is apt to perform a pivoting movement since it is hinged at the lower portion of the screen), which, by rotating, sets the machine in emergency. Such a system is very easy and light and is independent of the movement of the protective screen <NUM>.

As for point c), suitably according to the present invention, the protection is given by the photocells <NUM>. In fact, said photocells are supported by the protective screen <NUM>, the arm <NUM> being arranged in a position that is substantially central with respect to the body of said protective screen <NUM>, so that, when the photocells are covered, the machine <NUM> stops before the arm <NUM> can touch the operator.

In an embodiment, as illustrated in <FIG> and <FIG>, the protective screen <NUM> is connected to the arm <NUM> through a pin element <NUM> (for instance projecting from a face of the body <NUM>' of the screen) housed in a suitable seat <NUM>' (for instance formed on the portion 4p that is projecting from the end of the arm <NUM> or directly in the body of the arm <NUM> and having a shape that is complementary to the pin), said connections being enough to ensure the desired effect.

From the above it is clear that, in a preferred embodiment of the present invention, a safety system is provided, which comprises the protective screen <NUM> hinged to the arm, the additional protection element <NUM>, which in turn supports the photocells <NUM>, thus forming substantially a unique safety element having multiple functions. However, other configurations are possible, in which the single elements could be separated from each other; for instance, as above mentioned, the photocells could be equipped with an own support that is directly fastened to the arm <NUM> (what matters is that said photocells <NUM> are arranged vertically to cover an area corresponding at least to the overall dimensions of the arm <NUM>, of the cutting unit <NUM> and of the carriage <NUM>), as well as the protective screen <NUM> could be associated with the machine <NUM> in other ways.

It is further noted that, in an embodiment, the additional protection element <NUM> may be connected to the protective screen <NUM> so as to be capable of translating with respect to said screen (for instance it may have an elongated body mounted on guides connecting it to the screen), the collision with the user causing in this case the translation of the additional protection element <NUM>. Obviously, all the considerations for the pivoting movement also exactly apply to the translating movement.

In any case, return elements are provided, which are connected to the protective screen <NUM> and to the additional protection element <NUM> (such as springs or pistons), configured to return said additional protection element <NUM> to the rest position after the collision, and thus after the translating or rotational movement.

Furthermore, in an embodiment of the present invention, an elastomeric protection element <NUM> is provided, which is also known in the field with the term "bumper" (it is substantially a compressible rubber protection), and which covers the arm <NUM> at the top. In this way, the elastomeric protection element <NUM> that is arranged above the arm <NUM> acts as covering element, thus preventing the operator from coming into contact with the cutting means also at the upper portion of the arm <NUM>, for instance slipping the hands from above, and also absorbs any collision.

In an embodiment, the elastomeric protection element <NUM> is in the form of a covering extending along the sliding direction by an extension that is substantially equal to that of the protective screen <NUM> (for instance so as to be in line with the photocells), as well as it extends in the transversal direction so as to cover the space between the two opposite protective screens. The elastomeric protection element <NUM> is arranged on the arm <NUM> (for instance in direct contact with its upper face), so as to wrap the carriage <NUM>. In any case, any suitable association mode is comprised in the scope of the present invention.

If the operator's body is arranged so as not to hit the protective screen <NUM>, when the arm of the machine approaches, then as a first thing a ray of the photocell <NUM> intervenes, and then in the upper part the operator comes into contact with the bumper, absorbing the collision. In any case, prior to the maximum compression of the bumper, the machine will be completely stopped.

In another embodiment, the covering of the arm <NUM> is not entirely formed by the elastomeric protection element <NUM>, but for instance by a simple covering (for instance a metal one) fixed to the arm <NUM>, the elastomeric protection element <NUM> being arranged on the edges of said covering. In this way, the elastomeric protection element <NUM> is kept distanced apart from the arm <NUM> by said covering (which is connected to the upper face of the arm <NUM>) and represents a partial covering element, still capable of absorbing a collision with the operator.

In an embodiment, the elastomeric protection element <NUM> is also arranged on the edges of the additional protection element <NUM>, thus ensuring further protection for the operator.

Finally, the machine <NUM> is equipped with control monitors <NUM>, projectors <NUM>, cameras and lights, said components being advantageously supported by the hanging crosspiece <NUM>, without the need of using other supports.

In conclusion, the present invention provides a cutting machine equipped with a protective screen close to the ends of the movable arm, said screen being shaped in order to avoid a direct contact of the operator with the cutting units. The protective screen is capable of integrally translating with the arm and is tilting with respect thereto, so that, when it hits against an obstacle, in particular when its lower portion that is the furthest from the arm hits an obstacle, it may rotate about the hinging axis, thus absorbing the collision and allowing the control unit to stop the operation of the machine on time and in total safety. A collision against the upper end of the screen, i.e. closer to the hinging point, is instead absorbed by an additional protection element that is for instance hinged to the lower end of the screen and is capable of performing a pivoting movement towards the edge of the screen, said movement activating the safety stop. The machine of the present invention is also equipped with other safety systems, such as photocells, thus making the cutting machine herein described extremely safe.

Advantageously, there is a significantly increased safety for the operator, since every possible factor of risk linked to the structure and operation of the cutting benches (i.e. cutting machines which are not equipped with a closed cutting chamber) is eliminated, or at least significantly reduced. In fact, according to the known solutions, there is only one photocell that is aimed at stopping the operation of the machine once the user's presence has been detected, for instance in case the presence of an operator's hand has been detected near the cutting unit. Conversely, suitably according to the present invention, in addition to safety provided by the photocells (which by the way cover a vertical space that is greater than the known solutions, thus offering greater protection), the above safety system is provided, which comprises the tilting screen (therefore providing additional safety with respect to the sole photocells), preventing a contact with the supports of the photocells themselves from causing an accident to the operator, said supports being installed on the tilting screen, in particular on the additional protection element, and being subjected to said relative movement once the collision has occurred. It is indeed noted that if the photocells may prevent, at least to some degree, a contact with the cutting head, only the safety system herein described is capable of reducing the effects of a collision with the photocells themselves, in addition to increase the safety provided by the sole photocells.

Suitably, the relative rotation of the protective screen during a collision is combined with the pivoting additional protection element, thus preventing a contact with said screen from causing accidents for operators.

All these measures make the present machine much safer with respect to the known solutions, thus making it particularly suitable for obtaining all of the major safety certifications, such as for instance the TUV certification.

It is thus clear that the machine of the present invention appropriately solves the technical problem, without excessively complicating the mechanical structure thereof. In fact, the complete safety for the user is obtained thanks to a simple, light, easy to install and economic structure.

Claim 1:
Machine (<NUM>) for cutting sheet material, comprising:
- a worktable (<NUM>) adapted to provide a support plane for a sheet of material to be cut;
- at least one cutting unit (<NUM>) adapted to cut the sheet arranged on the worktable (<NUM>);
- at least one arm (<NUM>) that is arranged at least partially above the worktable (<NUM>) and is adapted to support the cutting unit (<NUM>);
- support means (<NUM>) of the arm (<NUM>), which is supported so as to be movable along a sliding direction (X); and
- at least one protective screen (<NUM>) connected to the arm (<NUM>), said protective screen (<NUM>) being adapted to translate in the sliding direction (X) due to the movement of said arm (<NUM>),
said machine (<NUM>) being characterized in that the protective screen (<NUM>) is hinged at a hinging point (P) so as to be tilting with respect to the arm (<NUM>), said protective screen (<NUM>) being adapted to perform an at least partial rotation with respect to the hinging point (P),
wherein the machine (<NUM>) comprises a control unit (C) configured to stop the movement of the arm (<NUM>) based on the rotational movement of the protective screen (<NUM>).