FIELD OF THE INVENTION

The present invention relates to processing of flat articles, in particular cutting of leathers or similar materials, to obtain shaped pieces.

More in detail, the invention relates to a machine for moving, e.g. continuously, leathers and similar material and for cutting/etching the leathers .

BACKGROUND OF THE INVENTION

In the above mentioned technical field, the leathers must be well spread and perfectly stretched during the cutting and/or etching, by a suitable moving cutting unit. For this purpose, a first type of known machine includes a motionless work table, made e.g. of steel, and provided with a series of through holes, which are connected with a vacuum source (suction source), by connecting channels.

The perforated plate is usually wrapped with a protection covering, including a layer of highly permeable material, e.g. felt.

The work table is situated below an automatic, moving cutting unit.

The use of the felt layer allows creation of a kind of safety cushion between the cutting means of the cutting unit and the surface of work table, thus avoiding scratching of the table.

The operator spreads the leather to be cut and/or etched on the work table, the suction effect created by the suction source attracts and holds the so spread leather,

keeping it stretched during the operation of the cutting unit.

On one side, this kind of machine allows a perfect cutting and/or etching quality, due to the way of keeping the leather spread and well stretched, on the other side, it does not allow high production rate.

This is caused by the fact that after each cutting and/or etching operation, before a new operation of the cutting unit, it is necessary to wait until the operator removes the cut leather and the working residues from the work table and places thereon a new leather to be processed, spreading it.

The same technical field uses, although less often since they are more complicated to produce, machines which move the leathers below the cutting and/or etching unit.

These machines include a conveyor, which has an endless belt, mounted on corresponding toothed operation wheels, at least one of which is a driving wheel, so as to define an upper active run and a lower run. This type of machine includes also an automatic cutting unit, situated above the conveyor upper run, near its central area, and a motionless plate, situated directly below the upper run.

The plate has a series of through holes connected to a vacuum source (suction source) , and its longitudinal extension covers almost the whole longitudinal extension of the conveyor upper run, except for an initial and a final part of the latter, with respect to the belt feeding direction. The leathers to be cut and/or etched are placed and stretched by an operator above the initial part of the

conveyor upper run, and then they are moved by the conveyor, so as to transit above the motionless plate and toward the cutting unit.

The suction action of the motionless plate attracts towards itself the conveyor upper run, and consequently the leather spread thereon, thus keeping it in a substantially stretched configuration during its passage below the cutting unit.

In this way, the cutting unit can operate on a spread, stretched and moving leather.

After having left the upper run area engaged with the suction plate and having reached the final part of the same run, the so cut and/or etched leather is no more subjected to any suction action, therefore the operator can easily remove it, together with the processing residues, from the conveyor.

The advantage of this type of machine with respect to the machines with a motionless work table lies undoubtedly in the production rate increase. Actually, while one leather is cut and/or etched, it is possible to place another leather on the initial part of the conveyor, without waiting for the completing of the cutting operation performed on the first leather.

Thus, the central portion of the upper run of the conveying belt transiting above the perforated plate defines, together with the plate, a moving work plane, on which the leathers to be cut and/or etched are placed and stretched.

The belt used for the conveyor must have a central area, aimed at moving above the perforated plate, and two lateral areas, coupled with the central area, aimed at

engaging with the toothed operation wheels.

A first known machine uses a belt, whose central area is perforated and formed by a layer of a material, which is permeable and resistant, to some extent, to the cuts of the cutting unit, and which is compatible with the material, of which the two lateral areas are made.

The lower part of the lateral areas forms corresponding teeth for engaging with the toothed operation wheels .

However, the so made belt, used for the conveyor, is expensive and, beyond everything, its permeability is insufficient: this could require the activation of the vacuum source with particularly high pressure values, to ensure the leather adherence to the belt.

Consequently, it appeared that the conveyor upper run for moving leathers below the cutting unit in the known, so obtained machines, was subjected to slowdowns or had even been stopped and held by the perforated plate, due to the high suction force, which obviously affects the cutting operations . Another machine uses a belt, whose central area has a good permeability, so as to avoid possible slowdowns or stopping of the belt, and whose upper part has a layer of felt for protection from the action of the cutting means of the cutting unit. However, it appeared that, in the long run, the layer of felt tended to detach from and to displace with respect to the permeable material of the belt central area, and even to tear, which obviously affected the cutting precision and required the felt substitution. This is caused by the fact that the felt tends to lengthen, during its turning around the operation wheels,

and to shorten after the passage around the wheels.

Up to now, the above mentioned problems have considerably limited the use of machines with work table moved continuously for cutting and/or etching of the leathers and the like.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to propose a new machine for moving, e.g. continuously, and for cutting leathers and the like, which can avoid the disadvantages found in prior art so far.

In particular, the distinctive object of the present invention is to propose a new machine for moving and for cutting leathers and the like, which ensures a perfect adhering of the leather, in spread and stretched configuration, to the conveyor in any working conditions, thus preventing the conveyor from being slowed down or held by the perforated plate, and which at the same time, ensures the maintenance of a perfect tightness of the conveyor, at any required moving speed.

Another object of the present invention is to propose a machine, in which the suction plate, as well as the conveyor belt attracted thereby, are clear of any action of the cutting unit. The above mentioned objects are obtained, in accordance with the contents of the claims, by a machine for moving and cutting leathers and the like, including: a suction plate, having a plurality of through holes connected to a vacuum source; an automatic cutting unit, situated above said suction plate/

characterized in that it includes: a first endless conveyor, formed by a belt mounted around toothed operation wheels for defining an upper run and a lower run, with the upper run situated in such a way, as to overlap said suction plate and be near it, with said belt having a central area, made of impermeable material and passing above said plate, so as to be attracted by it and slide freely above it: a second endless conveyor, formed by a belt of impermeable material and mounted around toothed idle wheels and which defines an upper run for receiving leathers in spread configuration and a lower run, with said second conveyor being arranged in such a way that the idle wheels are outer with respect to said operation wheels of the first conveyor and that the upper run is interposed between said cutting unit and the upper run of said first conveyor, and is near the latter, said upper run of the second conveyor, together with the leathers spread thereon, being attracted to adhere to and to be pulled by the upper run of the first conveyor, due to the suction action of the suction plate, so as to pass below said cutting unit, so that the latter cuts said leathers and, at the same time, protects the central area of the upper run of the first conveyor and the plate from the action of the cutting unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristic features of the invention will be pointed out in the following description of a preferred, but not exclusive embodiment, with reference to the enclosed figures, in which:

Figure 1 is a schematic, front view of the machine

for moving and cutting leathers and the like, proposed by the present invention, as a whole;

Figure 2 is a schematic, partially top view of the machine proposed by the invention, during feeding the leather below a cutting and/or etching unit;

Figure 3 is a considerably enlarged view of the particular K of Figure 1;

Figure 4 is a schematic, front view of a possible different embodiment of the machine proposed by the present invention;

Figure 5 is a schematic, front view of another possible embodiment of the machine proposed by the present invention.

BEST MODES OF CARRYING OUT THE INVENTION

Having regard the enclosed Figures, the reference numeral 100 indicates the machine for moving and cutting leathers and similar, proposed by the present invention, as a whole . The machine 100, as shown in Figure 1, includes a motionless plate (1) , having a plurality of through holes (F) (Figure 3) , connected to a vacuum source (source of suction) .

The machine includes also an automatic cutting unit (T) , situated and acting above the suction plate (1) .

The distinctiveness of the machine (100) proposed by the present invention, with respect to prior art machines, lies in the fact that it includes a first endless conveyor (2), aimed at interacting with the suction plate (1) , as well as a second endless conveyor (3) , which is

aimed at receiving the leathers to be cut and/or etched, and which is connected to and interacts with the first conveyor (2) in the way described later on.

The above mentioned first endless conveyor (2) includes a belt (20) , wound around relative operation toothed wheels (22) and defining an upper, active run (21) and a lower, inactive run.

The belt (20) has a central area (23) , made of highly permeable material. The first conveyor (2) is arranged in such a way, that its upper run (21) is overlapped and near the upper surface of the suction plate (1) .

Consequently, the central area (23) of the belt (20) , due to its passage above the suction plate- (1) , is attracted by the latter and consequently, the upper run (21) of the conveyor is attracted to adhere to and to slither freely on the suction plate (1) .

The second conveyor (3) includes a belt (30) , made of permeable material, e.g. felt, and wound around relative idle wheels (32) , to define a lower, inoperative run, and an upper run (31) , which receives leathers (P) in spread configuration, to be cut.

The second conveyor (3) is arranged with respect to the first conveyor (2) in such a way, that the idle wheels (32) are outer with respect to the operation wheels (22) of the first conveyor (2) , and the upper run (31) is interposed between the cutting unit (T) and the upper run (21) of the first conveyor (2), and near the latter.

In virtue of this particular display, the upper run (31) of the second conveyor (3) is subjected to the suction action of the suction plate (1) , due to the high

permeability of the central area (23) of the belt (20) of the first conveyor (2) . In this way, the upper run (31) of the second conveyor (3) is attracted, together with the leathers (P) spread thereon due to its permeability, and held adhering without any sliding, and pulled by the upper run (21) of the first conveyor (2), as a result of the suction action of the plate (1) on the latter.

This way, any kind of problems are eliminated concerning the use of felt belt, found in known machines, because the felt belt (30) can be wound around idle wheels (32) without any stretching corresponding to the stretching of the belt (20) of the first conveyor (2) : actually, it is the suction action of the plate (1) to keep the felt perfectly adhering, without any sliding, to the upper run

(21) of the first conveyor (2) .

Moreover, due to the permeability of the upper run (31) of the second conveyor (3) , also the leathers placed thereon are subjected to the suction action of the plate (1) : consequently, they are kept perfectly stretched on the upper run (31) .

This allows the machine (100) to move the leathers (P) in spread and perfectly stretched configuration below the cutting unit (T) , and to protect the central area (23) of the upper run (21) of the belt (20) of the first conveyor (2), as well as the upper surface of the suction plate (1), due to the interposition of the felt upper run (31) of the second conveyor (3) .

In practice, the machine (100) proposed by the present invention assures: a suitable stretching of the upper run (21) of the first conveyor (2) , since it is attracted, kept

adhering and brought to slide freely on the suction plate (1); the contemporary moving of the felt belt (30) of the second conveyor (3) , together with the leathers (P) spread thereon; the adhering and stretching of the felt (30) and the leathers (P) to the upper run (21) of the first conveyor (2) .

Moreover, the machine (100) ensures the protection of the belt (20) of the first conveyor (2), as well as of the suction plate (1) , from the action of the cutting unit (T) , by the felt belt (30) of the second conveyor (3) , interposed between the leathers (P) and the first conveyor (2) . These characteristics are ensured without any problems related to the way, in which the felt is coupled with the permeable central area of the first conveyor by the suction action of the plate (1) , and to the stretching of the felt with respect to the belt, unlike the prior art machines .

Other characteristic features of the machine (100) proposed by the invention are described in the following.

The belt (20) of the first conveyor (2) can be operated continuously by the operation wheels (22) in a movement direction (M) , or intermittently, according to the operation needs.

The diameter of the idle wheels (32) of the second endless conveyor (3), like shown e.g. in Figure 1, is bigger than the diameter of the operation wheels (22) of the first endless conveyor (2) .

According to the embodiment shown in Figure 4, the second

endless conveyor (3) can have, in correspondence to each of its winding ends, a plurality of idle wheels (32) (for example a pair) , whose diameter is smaller than the diameter of the operation wheels (22) of the first conveyor (2) .

According to another, particular embodiment, shown in Figure 5, the second endless conveyor (3) can have only one idle wheel (32) , near the conveyor winding end, situated downstream of the cutting unit (T) with respect to the feeding direction (M) .

The idle wheel (32) has a diameter smaller than the diameter of the operation wheel (22) of the first conveyor (2) and is situated below the rotation axis, with respect to the operation wheel (22) . In this case, the second conveyor (3) can have, on its winding end, situated upstream of the cutting unit (T) , either only one idle wheel (32) , whose diameter is bigger than the diameter of the operation wheel (22) of the first conveyor (2) (as shown in Figure 5) , or a pair of idle wheels (32), whose diameter is smaller than the diameter of the operation wheel (22), as shown in Figure 4.

The presence of only one idle wheel (32) at the winding end of the second conveyor (3) , situated downstream of the cutting unit (T) , whose diameter is smaller than the diameter of the operation wheel (22) of the first conveyor (2) , situated below the rotation axis of operation wheel (22) , allows the belt (30) of the second conveyor (3) to turn around an angle section smaller than 90° of the operation wheels (22) of the first conveyor (2) .

This advantageously allows a considerable reduction of

the machine dimensions downstream of the cutting unit (T) , thus ensuring larger work space for the operator.

The belt (20) of the first conveyor (2) includes also two lateral areas (24) of plastic material, each of which has an outer portion, whose lower part forms a gear cutting, coupling with a corresponding gear cutting of the operation wheels (22) , and an inner portion, whose lower part is aimed at overlapping the lateral portions (23) of the belt (20) . In order to ensure a stable and permanent coupling between the lateral areas (24) and the central area (23) , the belt (20) includes at least one first strip (not shown) , made of a material compatible and heat-weldable with the plastic material of the lateral areas (24) , and situated below the extreme lateral portions of the central area (23) , opposite to a relative central portion of the lateral areas (24) .

After being heat-welded, the strip material melts and passes through the extreme lateral portions of the central area (23) , so as to be heat-welded with the corresponding inner portion of the lateral areas (24) , clamping the extreme lateral portions between the strip and the inner portions of the lateral areas (24) , thus ensuring their mutual coupling. The belt (20) of the first conveyor (2) can also have at least a second strip (likewise not shown) , made of a material compatible and heat-weldable with the plastic material of the lateral areas (24) and of the first strip, and interposed at least partially between the lower part of the inner portion of the lateral areas (24) and the extreme lateral portions of the central area (23) , at least partially opposite to the first strip.

Like in the previous case, the material of the upper part of the second strip welds directly with the inner portion of the lateral areas (24) and the lower part of the second strip melts and passes through the extreme lateral portions of the central area (23) , so as to be heat-welded with the first strip, consequently clamping the extreme lateral portions of the central area (23) between the first strip and the second strip, in order to strengthen the coupling between the central area (23) and the lateral areas (24) .

Advantageously, the material of the central area (23) of the belt (20) of the first conveyor (2) is made of a synthetic fabric, impregnated with PVC and woven in such a way, as to define a plurality of through holes. The first strip and the second strip are made of polyurethane, which is highly compatible with the plastic material of the lateral areas (24) .

The lateral areas (24) can be made of resin, and the upper part of their outer edges and of the inner edges have threads made of metal, or strengthening kevlar.

It results from the above description that the machine (100) proposed by the present invention allows to resolve in a satisfactory way different problems described in the introductory note, which affect the prior art machines, reducing considerably the advantage of their use.

The machine (100) proposed by the invention assures to move the leathers, e.g. in a continuous way, below the cutting unit (T) , maintaining them perfectly stretched, and to protect the suction plate from the cutting means of the cutting unit, by the presence of the felt layer.

Further, the characteristic presence of two endless conveyors and their mutual arrangement, as it has been

previously described in detail, the felt belt is not subjected to any deterioration caused by excessive traction stress.

Moreover, the felt belt can be substituted easily, since it is mounted simply on two idle wheels.

It is understood that the proposed invention has been described, with reference to the enclosed figures, as a mere, not limiting example. Therefore, it is obvious that any changes or variants suggested by the use and applied thereto remain within the protective scope defined by the following claims.