FIELD OF THE INVENTION

The present invention relates to an improved laser marking apparatus, in particular a laser marking apparatus provided with a protective shield.

PRIOR STATE OF THE ART

As known, laser markers are apparatuses that employ a laser source, suitably focused and driven, to indelibly impress marks (brand, lot number, serial number, ... ) on production pieces, typically metal, but also plastic and organic workpieces. For such function, laser markers are typically equipped with a mobile unit that uses a medium and/or high power laser source: this is why they represent a potential source of health risk for workers (un der operating conditions that require regulations above the risk class II) . Therefore, it is essential that these apparatuses are suitably protected to avoid accidentally exposing operators to direct laser light.

Currently the protection is obtained by arranging the appa ratus as an isolated booth, equipped with controlled access, in side which there is a laser marker provided with its laser source and respective optics. This access control implies that the laser marker can operate only when the protection system is in an ap propriate position, which prevents the presence of the operators in close proximity to the laser marker working area. See for example US2007/23406.

The shielding booth of the laser marker determines a sort of stable protection, which encloses the access perimeter to the working area of the laser source. The booths have access doors that are opened for the introduction of workpieces and then closed again during operation. The protection booths are also widely used in other sectors of machine tools and sometimes they can also offer some solutions to reduce the overall bulk when the machine tool is not operating: EP3257638, for example, discloses a down wards collapsible cabinet, in which the machine tool also lowers downwards when it is not in use. Similar collapsible booth solutions are described in DE202010007645U and US5129611.

It is evident that such solutions involve operating limits on the dimensions of the workpieces that can be marked. In fact, the space occupied by the booth, and therefore the size of the access doors, does not allow to introduce pieces of significant size when the marker is in operating order. The limits of these solutions are determined both by the access door dimensions, but also by the fact that the workpiece must be introduced by a ver tical access compartment and therefore must be typically placed by hand or by a robotic arm: this limits the access of heavy parts that, for example, must be transferred with a forklift or an overhead crane and therefore require access from above or trans versely to the working deck of the laser marker.

Alternatively, it is possible to operate in the opposite way, i.e. a large working area is destined to the laser marker - which can be accessed comfortably and freely by any means - and then it is possible to limit the access of operators to the area before starting the apparatus: typically this is achieved by in stalling the laser marker in a room with a controlled access door. This solution is unwelcome because it obliges users to dedicate an entire working area to the laser marker, including large re quired distances that are then unusable by the operators during the operation of the laser marker.

As understandable, none of these techniques is therefore completely satisfactory.

PROBLEM AND SOLUTION

The object of the present invention is to overcome the draw backs of the prior art as set forth above. In particular, it is intended to provide a marking apparatus that can work in protected conditions, without forcing an entire access area to be dedicated and without the limits of known protection apparatuses.

This object is achieved by the features mentioned in claim 1. The dependent claims describe preferred features of the inven tion .

In particular, according to a first aspect of the invention, a laser marking apparatus is provided herein, comprising a support frame of a working deck and a laser marking head operating above said working deck, and wherein a protection shield is arranged around said working deck, which fully encircles the working area of said laser marking head and provided with panels at least partly perimetrally upright arranged with respect to said working deck, wherein said panels are mounted movable from a lower posi tion, wherein said shield surrounds said support frame up to a height completely below or flush with the upper surface of said working deck, to an upper extended position wherein said shield surrounds the area above said working deck up to a working height of said laser marking head.

According to another aspect, vertically upright panels are mounted vertically slidable with a rigid displacement. Alterna tively, each of the panels consists of a plurality of sub-panels arranged side-by-side and at least partly mutually movable by means of a telescopic mechanism. Preferably, at least part of said sub-panels are in the shape of winding flexible shields.

According to a preferred aspect, at least one front panel is mounted movable autonomously from the other panels. In particular, the front panel is mounted free to slide vertically and con strained by a pneumatic dampener adjusted to support the weight of said panel and to inhibit the descent thereof due to gravity.

According to a variant, the shield panels also comprise an upper closing panel extendable from a backward closed-up position to a forward extended position. In particular, the upper closing panel is in the shape of a roller shutter or of a plurality of telescopically extendable sub-panels.

According to another aspect, at least one of the perimetrally upright arranged panels is offset from the working deck so as to define a vertically extending compartment, in which the laser marking head is movably housed. In this case, an upper opening of the compartment is closable by at least part of the upper closing panel when the perimetrally upright arranged panels are in the lower position.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will anyhow be more evident from the following detailed description of a pre ferred embodiment, given by mere way of non-limiting example and illustrated in the accompanying drawings, wherein:

fig. 1A is a top perspective view, of a first embodiment of the apparatus according to the invention in a lowered shield home condition;

fig. IB is a perspective view of the apparatus of fig. 1A in an open condition of a laser marker housing compartment;

fig. 2 is a perspective view of the apparatus of fig. 1A, in a set-up condition;

fig. 3 is a front elevation view of the apparatus of fig. 2; fig. 4 is a perspective view of the same apparatus of fig. 3, in a first closing condition of the protection shield;

fig. 5 is a side elevation view of the apparatus of fig. 4 with partially removed parts;

fig. 6 is a top perspective view of the same apparatus of fig. 4, in an operating condition of the marker with completely closed protection shield;

fig. 7 is a perspective view from one side and from the front, with partially removed parts, of the first embodiment in the operating condition of fig. 6;

fig. 8 is a perspective view from one side and from the rear similar to that of fig. 7;

fig. 9 is another perspective view similar to that of fig. 7 with the marker in operation;

fig. 10 is a perspective view with removed parts of the apparatus of fig. 1A;

fig. 11 is a perspective view, with removed parts, of the apparatus according to another embodiment of the invention in a lowered shield home condition;

fig. 12 is a perspective view of the apparatus of fig.

11 in a set-up condition; and

fig. 13 is a perspective view, with removed parts, of the apparatus of fig. 11 in a partial closing condition of the pro tection shield. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Fig. 1A shows an apparatus according to a first embodiment of the invention, in a non-operating condition.

It should be noted a perimeter shield 1 which encicles a lower area of a support frame T which supports a working deck 2.

More precisely, the frame T consists of lattice elements T1 and T2 which define a mobile support structure for the perimeter shielding 1 (as will be explained below) and for stable constraint of the working deck 2.

The working deck 2 is integral with the frame T and consti tutes the support plane for the workpieces during operation of the laser marker. Deck 2 therefore defines a flat, stable and sufficiently hard and resistant surface to support even pieces of significant weight. For this purpose, the deck 2 is preferably in the form of a plate of rigid and stable material (for example granite) of the type used in machine tools or precision scanning probes .

The frame T supports the working deck 2 at a suitable height so that an operator OU can access it comfortably. Furthermore, the perimeter shielding 1, in the non-operating condition as il lustrated in figs. 1A-2, has a height such as to remain flush or in any case entirely below the upper surface of the working deck 2 when it is in its lowered position: in this way, it is possible to access the working deck comfortably, both sideways that from above, without interfering with the perimeter shielding that re mains entirely at a lower level.

At least on one side of the working deck 2 - in the figures, a back side of a generally rectangular plan shape (even if the deck 2 could have also a regular or irregular polygonal shape, having more than four sides, or other shapes) - the perimeter shielding 1 is arranged at a certain distance from the edge of the working deck 2 (see Fig. IB) , so as to define a compartment 3 vertically accessible between the plane 2 and the corresponding side of the perimeter shield 1. In this compartment 3 movement means M are accommodated, said means being suitable for raising and lowering, respectively above and below the level of the working deck 2, a laser marking head 4, as better described in the following.

According to the preferred embodiment shown, the other three sides of the perimeter shielding are arranged adjacent to the side and front edges of the working deck 2, so as to occupy the area of minimum size with respect to the plant footprint of the working deck 2.

Preferably, as made evident by the comparison of figs. 1A and IB, the compartment 3 for housing the marking head is provided at the top with a movable cover, for example a portion of an extendable shutter TP, as better described below.

Fig. 2 shows the apparatus in a set-up condition, in which a piece 5 to be marked was deposited on the working deck 2 and the marking head 4 is extracted from the compartment 3 and arranged in operating condition.

As can be seen from fig. 2, the movement means M comprise a simple or telescopic vertical guide 4a, with its own driving de vice, an articulated arm 4b and an engaging articulation 4c for a marking laser head 4. It is not necessary to explain in detail the component parts of the laser marker 4, as these are elements commercially available from the mark, for example the UNIQ™ model of the Datalogic™ company.

The elements illustrated above are also visible in the front view of fig. 3, showing the upward development of these elements, with respect to the height of a medium height operator OU. In this figure it is further noted that the whole of these elements, including the workpiece 5 to be marked, has a height from the working deck 2 of a height lower than the height of the perimeter shield 1 and therefore of the height of the working deck 2 from the ground.

The perimeter shield 1 is mounted on the frame T in a ver tically extensible way, so as to be displaced from a lowered attitude - in which it encircles the frame T and remains entirely at a level lower than that of the working deck 2 (Figures 1A-3) - to a raised attitude - in which it delimits at least the sides of the working deck at the height of the marking head 4. According to a first embodiment illustrated in figs. 4-10, the perimeter shield is in the form of vertically sliding mounted panels. Although the entire side surface of the perimeter shield 1 can move integrally upwards and downwards, preferably at least one of its front portions is mounted vertically movable inde pendently of the remaining shield 1 portions: this makes easier the access by the operator OU when it is necessary to use the apparatus with frequent batches of small pieces to be marked, as will be seen further on.

Fig. 4 shows the structure of the perimeter shield 1 in a fully vertically raised position. It can be noted that the perim eter shield 1 in this case consists of three integral panels PI, P2 and P3 on the two sides and on the back side, while a fourth front panel P4 is vertically sliding on the frame T independently (in Fig. 4 it is in the lowered position) .

This provision is not binding, in the sense that other ar rangements could be provided in which the walls of the perimeter shield move vertically in a different way.

Possibly also the upper side can be closed. In this case, on the upper side there is provided a shutter TP, horizontally slid able and extensible by a collection fold TP' which is housed in the rear compartment 3 (see Figures 5-7-10) .

The upper shutter TP, in the completely folded position (fig. IB) , is located TP' housed inside the rear compartment 3, while in the fully extended position (fig. 6) it extends horizontally, above the working deck 2, by sliding in proper lateral guides, at a height higher than the various elements of the laser marker 4.

When the perimeter shield 1 is completely lowered (fig. 1A) , the shutter TP - which is part of the shield - is necessarily folded so as not to interfere with the deck 2. In the case where a compartment 3 for housing the head 4 is provided, when the latter is in a non-operating position, the shutter TP can be briefly extended to close the compartment 3 above, until it abuts against the rear edge of the working deck 2.

It should be noted that the operating condition of the ap paratus - that is, the one that generates the consent to start the laser marking head 4 - is not that shown in Figures 4 and 5, but that in fig. 6, in which also the front panel P4 was in turn completely lifted and the shutter TP was moved horizontally for ward, until reaching the upper edge of the panel P4, to complete the closure of the perimeter shield around the marking laser head 4.

The fact that the front panel P4 has a vertical movement independent of the remaining perimeter shield portion, entails operating advantages. In fact, when the apparatus of the invention must be used in a traditional way, that is to mark small and handy workpieces, the perimeter shield 1 can be left in the raised/ex tended arrangement shown in fig. 5 while acting only on the panel P4, lowering it or lifting it every time it is necessary to in troduce and extract the pieces to be marked. The provision of a closing and opening of only the front panel P4 obviously makes the parts change operations, and therefore the productivity of the machine, faster. When, on the contrary, it is desired to exploit the peculiarities of the apparatus according to the in vention, to load bulky or heavy pieces on the working deck 2, the whole perimeter shield can be lowered and lifted.

In figs. 7-10 the apparatus according to the first embodiment is shown in transparency, i.e. having removed the shield panels to show the internal elements defining the movement elements for opening and closing the shield.

It should be noted that the three rear and side panels PI PS are mounted integral with each other and fixed to tracks B vertically slidable in guides G attached to the frame T. The vertical movement is ensured by an electric motor R1 which con trols in rotation two opposed toothed gears R2, engaged on re spective toothed racks R3, integral with the perimeter shield.

In the case where the front panel P4 is mounted movable and independent from the remaining shield portion, a system of dedi cated guides and tracks is provided: in this case, a manual lifting system for the panel alone is sufficient, in view of the greater lightness, for example an articulated pantograph mechanism GF equipped with a pneumatic dampener GF1 that maintains the position of the panel P4 set manually by the operator. Alternatively, it is possible to provide a pneumatic or electric actuator, with automatic or manual control, which actively lifts and lowers the front panel.

The unrolling and rolling up movement of the shutter TP can also be motorized by known systems, for example by means of loop- mounted transmission belts within two upper side guides TP i and TP 2 along which the two side edges of the shutter TP slide.

Also for raising / lowering the upright 4a of the laser marker 4 an electric motor RR suitably controlled by industrial automation is preferably provided.

Figs 11-13 schematically illustrate a second embodiment of the invention.

Here the laser marking head 4 is mounted at the end of a robotic arm, which equivalently replaces the articulated system of fig. 2, but is not decisive for the purposes of the teaching of the invention.

In this embodiment, the perimeter shield comprises composite panels P5, P6, P7 (a side panel P6 and the rear panel P7 are not shown in the figures) , constituted by a system of contiguous sub panels, arranged side-by-side and reciprocally sliding at least partly with a telescopic mechanism with respect to one another: this determines a mode of vertical extension of the side panels which is not defined by a single rigid displacement, but by mutual sliding of the sub-panels one adjacent the other.

To this end, the sub-panels are engaged with each other by sliding guides PG ₁ -PG ₃ provided along the respective side edges. When the sub-panels of the same panel are superimposed on each other (see panel P5 in fig. 11) in the lower part of the support frame, the smaller overall height is obtained. When, on the other hand, the sub-panels slide on each other and extend upwards of the maximum available travel, the panel takes the maximum exten sion in height (see the same panel P5 in fig. 13) . In the com pletely lowered configuration of the perimeter shield, therefore, only the external panel of each of the said telescopic movement systems is visible, while the other sub-panels of the same panel are staggered and arranged side-by-side inwards.

The innermost or outermost sub-panel of each panel is con trolled according to a raising/lowering motion and, in this move ment - upon reaching a predetermined stroke - it also draws the adjacent one and so progressively the more external or internal ones. Typically, it is believed that three sub-panels are suffi cient for each perimeter shield panel. The controlled sub-panel is preferably moved by suitable lifting members, constituted by mechanical pantographs GF, driven by an electric motor RG and possibly supported by automatically controlled pneumatic dampers.

Preferably, at least the lower sub-panel (i.e. the one that remains in the lower part when the panel is extended upwards) is not rigid, but is in the form of a winding flexible shield, with a spring rewinding. The flexible shield is unrolled during the vertical movement upwards and rewinds due to the return spring, during the vertical movement downwards (in the shield closing phase) .

The same construction is used both for the side panels P5- P7 and for a front panel P8.

In the preferred case in which the front panel P8 is mounted movable and independent of the remaining shield portion, an auto matic or manual lifting system similar to that provided in the first embodiment is provided.

The upper side of the perimeter shield can also be equipped with a closing system P9 with a telescopic mechanism. In this case, to obtain the minimum covering dimensions of the extraction compartment of the laser marker 4, the mutually sliding sub-panels could be more than three, for example four.

The other components and operating methods are completely equivalent to those of the first embodiment.

This embodiment, by contemplating sub-panels arranged side- by-side (of which, possibly, a part that can be wound up) in the lowered home position, can have a perimeter shield of height much greater than the limit imposed by the height of the working deck 2.

The operation of the apparatus according to the invention involves lowering the shield to the lower limit, entirely below the working deck 2, when access to the deck 2 is required with bulky or heavy pieces (which require access from above with an overhead crane or from the side with a forklift) . During opera tion, the shielding is in any case raised, so as to encircle and close at least laterally the area of the working deck 2, thus avoiding any accidental reflection of the laser beam outside the working area. If the laser source requires it, it is possible to build shield panels with materials that are particularly suitable for resisting or reducing reflections of the laser beam.

As can be easily understood, through the apparatus according to the invention, a high compactness and flexibility of the shield available to the laser marking head is achieved, therefore a much smaller operating space compared to the prior art, while allowing very easy access to the working deck also for large and heavy pieces .

Practical tests have demonstrated the perfect functionality of this protective apparatus, which can be used not only for a laser marking machine, but also for any other machine that oper ates with high power lasers on reduced size pieces.

The apparatus of the invention increases the flexibility of use of the laser marker and can be installed in areas without controlled access.

It is understood, however, that the invention is not to be considered as limited by the particular embodiments illustrated above, which represent only exemplary implementations of the same, but different variants are possible, concerning in particular the opening and closing modes of the shielding booth walls, all within the reach of a person skilled in the art, without departing from the scope of the invention itself, as defined by the following claims .

For example, although it is preferable that the laser marking head can re-enter the compartment below the working deck so as to remain more protected with respect to any interference with mem bers for moving the workpieces that occupy the area above the work surface, this is not strictly necessary: the laser head could also be placed permanently above the working deck.