BACKGROUND OF THE INVENTION

The object of the present invention is a sheet-metal punching machine.

PRIOR ART

Sheet-metal punching machines are known, for example for making holes and cuts in panels and other components of domestic appliances such as refrigerators, washing machines and dryers, dishwashers, ovens and other domestic appliances.

Such machines comprise a rotating turret on which a series of punches is mounted and, correspondingly, a rotating base is provided comprising a series of dies, each intended for being coupled with a respective punch. The punches are driven by a single hydraulic drive; the punch to be driven is carried by the turret at the hydraulic drive. The sheet metal is moved by a suitable positioning unit that moves along two axes that are perpendicular to one another. The sheet metal is conveyed to the punch and die that have to make the hole or cut and the hydraulic drive drives the punch, which combines with the die to form the hole or cut in the sheet metal.

These punching machines have been found to be rather bulky and to have a fairly complex structure and operation.

Further, with these punching machines it is possible to perform only one punch at a time. Lastly, moving the sheet metal can lead to an imperfect alignment of the sheet metal with the punch and can cause damage to the sheet metal.

OBJECT OF THE INVENTION The object of the invention is to overcome the aforesaid drawbacks of known punching machines. SHORT DESCRIPTION OF THE INVENTION

This object is achieved by a sheet metal punching machine according to claim 1.

SHORT DESCRIPTION OF THE DRAWINGS

In order to understand the invention better, an embodiment thereof is disclosed below by way of non-limiting example, illustrated in the attached drawings in which:

Figure 1 is a front perspective view of a sheet-metal punching machine according to the invention;

Figure 2 is a front view of the machine in fig.1 ;

Figure 3 is a rear view of the machine in fig. l ;

Figure 4 is a left side view of the machine in fig. l ;

Figure 5 is a top view of the machine in fig. l ;

Figure 6 is an enlarged right side schematic section showing some details of the machine in fig.1.

DETAILED DESCRIPTION OF THE INVENTION

With reference to fig. l, the illustrated sheet-metal punching machine is generally indicated with 10 and consists of a punching unit 1 1 and of a positioning unit 12.

The punching unit 11 comprises a supporting frame 13 on which two toothed longitudinal guides 14 are fixed that are parallel to one another and oriented along an axis X.

On the frame 13 a slide 15 configured as a C is mounted that engages with the guides 14 and is slidable thereupon. With particular reference to fig. 3, for moving the slide 15 an electric motor 16 is provided that is mounted on the slide 15. The motor 16 is connected axially to a pinion 17 that engages with a longitudinal rack 18 fixed to the frame 13 and parallel to the guides 14.

With reference to fig. 6, on the upper arm 22A of the slide 15 a series of punches 19 is mounted, each driven by a respective hydraulic drive 20. Each hydraulic drive 20 is provided with a respective piston 21 that drives the respective punch 19. At the punches 19, on the lower arm 22B of the slide 15 there is mounted a corresponding series of dies 23, which are intended for coupling with the respective punches 19.

The details of the punch and of the die are not illustrated because they are of known type. The punch has a cylindrical body inside which the punching member proper is housed that is driven by the piston of the hydraulic drive; in the cylindrical body a spring is also housed for elastically recalling the punching member to the rest position once the punching member has been driven. The die has a hole of a shape corresponding to that of the punching member, inside which the punching member is inserted in the operating step.

The positioning unit 12 comprises a frame 24 on which is mounted a series of longitudinal belt- shaped brush mats 25, which are parallel to one another, having the function of supporting the sheet metal to be positioned.

In the central part of the positioning unit 12, between the belt-shaped mats 25, a longitudinal gap is obtained along which a rotating table 26 runs that is provided with suction cups 27 that are activated by a vacuum system which is not illustrated. With particular reference to figures 2, 4, the rotating table 26 is mounted, for moving, on a carriage 28 that is movable along longitudinal guides 29 that are directed along an axis Y, which is indicated in figs 1, 5, which is perpendicular to the axis X. With the table 26 an electric motor 30 is integral that is connected, via a reduction gear 31, to a pinion 32 that engages with a longitudinal rack 33.

Still with reference to figures 2, 4, for the rotation of the rotating table 26 a further electric motor 34 is provided that is integral with the table 26 and connected via a reduction gear 35 to a cam-type kinematic mechanism, which is not illustrated, that transmits the rotation of the shaft of the motor 34 to the table 26.

On the front part of the positioning unit 12 there is provided a series of reference pegs that enable the sheet metal to be positioned initially correctly on the unit 12. With particular reference to figures 1, 4, 5, a transverse row of reference pegs 36 is provided mounted on a fixed frame 37 and a pair of reference pegs 36 mounted on a movable frame 39 and arranged along an axis cutting the axis along which the pegs 36 are arranged. The operation of the sheet- metal punching machine 10 is the following.

The rotating table 26 is taken to the front part of the machine 10 by driving of the motor 30. The sheet of sheet metal is rested on the rotating table 26 and on the belt- shaped mats 25. The reference pegs 36 and 38 enable the sheet metal to be positioned correctly by placing the sheet metal against such reference pegs.

At this point the suction cups 27 are activated to lock the sheet metal on the rotating table 26 and the rotating table 26 is then moved to take it to the rear part of the positioning unit 12 so that the part of the sheet metal to be punched is at the punches 19.

For the punching, the hydraulic drives 20 are activated that drive the punching members that lower and penetrate the corresponding die to produce holes and/or cuts in the sheet metal.

The rotating table 26 moves the sheet metal along the axis Y and rotates the sheet metal whilst the slide 15 moves the punches and the dies along the axis X. In this manner, drilling and cutting the sheet metal where required can be performed with precision.

It is obviously possible to drive only one punch at a time or several punches simultaneously, depending on need.

The punching machine 10 is rather compact and has a structure and function fairly simple, owing to the absence of punch-holding rotating turrets. Also the movement of the positioning unit along a single axis contributes to the compactness and simplicity of the machine.

Further, with the punching machine 10 it is possible perform one punch at a time or perform several punches at a time.

Lastly, the movability of the punches along an axis decreases the risk of an imperfect alignment of the sheet metal with the punch and the risk of damage to the sheet metal during positioning thereof.

It is clear that variations on and/or additions to what has been disclosed and illustrated above are possible.

In a simplified embodiment only the punching unit can be used and the sheet metal can be taken to the punching position manually.

The configuration, the type and number of illustrated components may vary according to need.