Technical Field

The present invention relates to a die for press-bending machines and a related press-bending machine.

Background Art

The press-bending machines are appliances used for bending sheet-shaped elements, such as sheet metals, metal or plastic products or the like.

The press-bending machines of known type are provided with a load-bearing structure on which a die is mounted defining a bending seat for the sheet- shaped element to be worked.

These machines are also provided with pressing means comprising a working tool, e.g. of the type of a punch, a forming or cutting element, movable on the load-bearing structure approaching/moving away from the bending seat. The pressing means bring the working tool close to the bending seat and allow it to interact with the bending seat itself to plastically deform the sheet- shaped element.

Depending on the shape of the bending seat and on the force exerted by the pressing means, the sheet-shaped element acquires a certain bend. A first type of dies is provided with a bending seat of the fixed type, i.e. having a predefined shape and size. According to the type of product to be obtained, the dies are removed and installed each time on the load-bearing structure of the press-bending machine in order to give the different bends required.

This first type of die, however, is not very practical, especially when it is necessary to carry out operations that require frequent changes in the bending parameters.

Such operations, in fact, entail frequent replacements of the dies with a consequent lengthening of times and an increase in the risk for the safety of operators; the dies of known type, in fact, are generally quite large and heavy and are difficult to handle.

To overcome this drawback, dies of the movable type are used, which are provided with a pair of plates arranged vertically, opposite each other and of elongated conformation, that define the aforementioned bending seat. The plates are mutually movable close to/away from each other to vary the dimensions of the bending seat.

Through this movement it is possible to carry out multiple bending operations based on the required parameters.

Nevertheless, also this second type of dies does have some drawbacks, mainly related to the difficulty of making products provided with conical surfaces.

To carry out this type of works, in fact, the plates must be subjected to precise adjustments and, at the same time, the sheet-shaped element must be continuously positioned with respect to the bending seat in order to carry out a series of partial bends.

It is easy to understand that these operations greatly increase the risk of errors and can therefore have an important influence on the quality of the product obtained, with the risk of invalidating the entire work.

As a result of these considerations, it is clear that the dies for press-bending machines are susceptible to further improvements.

Description of the Invention

The main aim of the present invention is to devise a die for press-bending machines and a related press-bending machine that allow accurate adjustment of the plates and of the conformation of the bending seat.

Another object of the present invention is to devise a die for press-bending machines and a related press-bending machine capable of making products of the conical type in a practical and accurate manner.

A further object of the present invention is to devise a die for press-bending machines and a related press-bending machine that allow minimizing the working time and the risks for the safety of the operators.

Another object of the present invention is to devise a die for press-bending machines and a related press-bending machine that allow overcoming the aforementioned drawbacks of the prior art within a simple, rational, easy, effective to use and low cost solution. The objects set out above are achieved by the present die for press-bending machines having the characteristics of claim 1.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become more evident from the description of a preferred, but not exclusive, embodiment of a die for press-bending machines and a related press-bending machine, illustrated by way of an indicative, yet non-limiting example, in the accompanying tables of drawings wherein:

Figure 1 is a schematic representation of a press-bending machine according to the invention;

Figures 2 and 3 are axonometric views of two different embodiments of the die for press-bending machines according to the invention;

Figures 4-7 are exploded axonometric views of an embodiment of the die according to the invention, in different operating configurations.

Embodiments of the Invention

With particular reference to these figures, reference numeral 1 globally indicates a press-bending machine for bending sheet-shaped elements.

In the context of the present disclosure, the term “sheet-shaped element” means a flat product, in which the dimensions of thickness are considerably smaller than the dimensions of length and width. In the specific case, the sheet-shaped element is of the type of a sheet metal, made of a metal, plastic, or other plastically deformable material. Again, by “plastically deformable material” is meant a material which, following a deformation, maintains the shape given by the deformation itself and does not return to its original shape.

The machine 1 comprises at least one load-bearing structure 2 and at least one working tool 3 associated in a movable manner with the load-bearing structure itself and configured to bend at least one sheet-shaped element L.

The machine 1 is, moreover, provided with a die 4 adapted, in use, to receive the working tool 3 to bend the sheet- shaped element L.

More specifically, the working tool 3 is arranged superiorly to the die 4 and is movable along a substantially vertical plane of movement, close to/ away from the die itself.

The die 4 comprises at least one supporting base 5 installable on a press bending machine 1 and at least one forming assembly 6 associated with the supporting base 5 and defining at least one bending seat 7 of a sheet- shaped element L.

Specifically, the bending seat 7 is adapted, in use, to receive the working tool 3. The forming assembly 6 comprises at least one pair of plates 8 arranged vertically, opposite each other and of elongated conformation.

The plates 8 extend lengthwise along a substantially horizontal direction of longitudinal extension; each of the plates 8 is provided with a first extreme portion 8a and a second extreme portion 8b.

Thus, the pair of plates 8 comprises a first pair of first extreme portions 8a and a second pair of second extreme portions 8b.

According to the invention, the die 4 comprises at least one movement assembly 9, 10, 11 of the plates 8 adapted to allow the variation of their mutual inclination and/or distance.

The plates 8, in fact, are mutually movable to vary the conformation of the bending seat 7.

Specifically, the plates 8 can be positioned in at least one parallel configuration, wherein each of the first extreme portions 8a and each of the second extreme portions 8b, placed on the respective plates 8, are equidistant with respect to a vertical plane V passing through the bending seat 7.

Substantially, in such a parallel configuration, the plates 8 are parallel to each other and, therefore, they are also parallel with respect to the vertical plane V.

In more detail, the vertical plane V coincides with the plane of movement of the working tool 3 and defines a plane of symmetry of the bending seat 7.

The plates 8 are, also, positionable in at least one inclined configuration, wherein one of either the first pair of first extreme portions 8a or the second pair of second extreme portions 8b has the respective extreme portions 8a, 8b mutually close with respect to the vertical plane V passing through the bending seat 7, and the other of either the first pair of first extreme portions 8a or the second pair of second extreme portions 8b has the respective extreme portions 8a, 8b mutually moved away with respect to the vertical plane itself.

In such an inclined configuration, the mutual distance between the first extreme portions 8a is different from the mutual distance between the second extreme portions 8b.

Substantially, the plates 8 are arranged inclined to each other and inclined with respect to the vertical plane V.

In other words, in the inclined configuration the plates 8 lie on a plane transverse to the vertical plane V, respectively.

The movement assembly 9, 10, 11 therefore has the function of positioning the plates 8 in one of the possible configurations, parallel or inclined, depending on the required parameters, so as to allow multiple types of bending of the sheet shaped element L.

In particular, in the inclined configuration, the interaction between the working tool 3 and the bending seat 7 allows carrying out the work of the sheet-shaped element L to obtain a bending of the conical type.

The movement assembly 9, 10, 11 comprises at least two pairs of guidance portions 9 which can be mutually moved close to/away to position the plates 8 with respect to the vertical plane V.

The plates 8 are moved jointly with the movement of the guidance portions 9. It follows that the mutual close/away movement of the pairs of guidance portions 9 results in the respective mutual close/away movement of the plates 8. Specifically, as shown in Figure 4, each of the pairs of guidance portions 9 is associated inferiorly with each of the plates 8.

The guidance portions 9, when moved close to each other, define a polygonal abutment profile.

The movement assembly 9, 10, 11 also comprises elastic means 10 of connection between the pairs of guidance portions 9, interposed therebetween and adapted to counteract the approach of the pairs of guidance portions 9. Specifically, the elastic means 10 comprise a pair of springs arranged transversely with respect to the vertical plane V and shaped so as to load themselves, under contraction, as a result of the mutual approach of the guidance portions 9 and to generate an opposite counteracting force capable of moving the guidance portions themselves apart from each other.

Conveniently, the movement assembly 9, 10, 11 comprises inclination variation means 11 for varying the mutual inclination of the plates 8.

The inclination variation means 11 are adapted to move the first pair of first extreme portions 8a independently of the second pair of second extreme portions 8b.

In other words, the inclination variation means 11 have the function of moving the guidance portions 9 of the pair of plates 8 so as to move the plates themselves to the inclined configuration.

The inclination variation means 11 comprise at least one guidance element 12 associated in a movable manner with the supporting base 5 and adapted to operate in conjunction with the guidance portions 9 for the positioning of a respective pair of extreme portions 8a, 8b.

The guidance element 12 comprises at least one contact surface 12a having a “V” shape which is substantially complementary to a vertex of the polygonal abutment profile and adapted to abut against the vertex itself.

In other words, the sliding of the guidance element 12 on the supporting base 5 results in an increasing interaction between the contact surface 12a and the guidance portions 9 which results in a mutual approach of the latter and of the respective extreme portions 8a, 8b.

In the embodiment shown in the figures, the inclination variation means 11 comprise a pair of guidance elements 12 arranged on opposite sides of the supporting base 5 and provided with respective contact surfaces 12a facing each other.

Each of the guidance elements 12 is adapted to operate in conjunction with a respective vertex of the polygonal abutment profile for the respective positioning of the first pair of first extreme portions 8a and of the second pair of second extreme portions 8b.

In particular, the guidance elements 12 are arranged on the supporting base 5 symmetrically with respect to a transverse plane T substantially perpendicular to the vertical plane V.

Each guidance element 12 is movable in a sliding manner along a direction of sliding S substantially perpendicular to the transverse plane T and parallel to the vertical plane V.

In more detail, each guidance element 12 is movable between a home position, wherein it is arranged in the proximity of a side edge of the supporting base 5 and wherein the respective guidance portions 9 are moved away from each other, and at least one working position, wherein it is arranged in the proximity of the transverse plane T and keeps the respective guidance portions 9 close together.

In the home position, the guidance portions 9 are moved away from each other thanks to the action of the elastic means 10.

The variation of the distance of the guidance elements 12 with respect to the transverse plane T results in a variation of the mutual distance between the extreme portions 8a, 8b.

When both the guidance elements 12 are in the home position, they are equidistant from the transverse plane T and the plates 8 are in the parallel configuration.

At the same way, when only one of the guidance elements 12 is in the home position and the other guidance element 12 is in the working position, the plates 8 are in the inclined configuration.

Conveniently, the inclination variation means 11 comprise at least one actuating device 13 connected to at least one of the guidance elements 12 and adapted to move the guidance elements 12 independently of each other.

The actuating device 13 is associated with the supporting base 5 at a side edge thereof and is adapted to displace the guidance element 12 along the direction of sliding S between the home position and the working position.

In the present case, the actuating device 13 comprises a wedge-shaped element 14 associated with an evolving screw shaft 15 that is movable along a direction of actuation A substantially transverse to the direction of sliding S. More specifically, the wedge-shaped element 14 comprises a movement surface 14a adapted to abut against a corresponding abutment surface 12b defined on the guidance element 12.

The movement of the wedge-shaped element 14 along the direction of actuation A results in a gradual sliding of the guidance element 12 from the home position to the working position, which means that the sliding of the guidance element 12 from the home position to the working position results in a gradual approach of the first pair of first extreme portions 8a or of the second pair of second extreme portions 8b. As shown in the figures, the inclination variation means 11 comprise a pair of actuating devices 13 each connected to a respective guidance element 12 and independently operable with each other to move the guidance elements 12.

The actuating devices 13 are associated with the supporting base 5 at the side edges of the supporting base 5 opposite the transverse plane T. The independent actuation of the actuating devices 13 results in the independent movement of the guidance elements 12 and, consequently, allows positioning the plates 8 in the inclined configuration.

Conveniently, the movement assembly 9, 10, 11 comprises return means, not shown in detail in the figures, associated with the guidance elements 12 and adapted to move the guidance elements themselves from the working position to the home position.

In more detail, the return means comprise a pair of springs, each positioned between the supporting base 5 and a respective guidance element 12, and arranged parallel to the direction of sliding S. The return means are shaped in such a way as to load themselves, by extending themselves, as a result of the movement of the guidance element 12 towards the working position and to generate an opposite counteracting force capable of returning the guidance element itself towards the home position. Advantageously, the movement assembly 9, 10, 11 comprises extension variation means for varying the extension of the bending seat 7.

The extension variation means are adapted to move the plates 8 parallel to each other and to vary the distance between them.

In other words, the extension variation means are adapted to move the first pair of first extreme portions 8a and the second pair of second extreme portions 8b so as to maintain the plates 8 in the parallel configuration. For this purpose, the guidance elements 12 are moved between the working position and the home position so as to be positioned at the same distance from the transverse plane T.

In a preferred embodiment shown in the figures, the extension variation means coincide with the inclination variation means 11. Conveniently, the movement assembly 9, 10, 11 comprises position determination means 16 operationally connected to the inclination variation means 11 and adapted to measure a distance value between at least one of either the first pair of first extreme portions 8a or the second pair of second extreme portions 8b. The position determination means 16 allow determining the relevant position of the extreme portions 8a, 8b so as to allow the verification of the correct setting of the required bending parameters.

In the embodiment shown in Figures 1, 2, 4-7, the position determination means 16 are of the mechanical type and comprise at least one indicator element 17 associated with one of the plates 8 and at least one indicator scale 18 associated with the other of the plates 8.

In an alternative embodiment shown in Figure 3, the position determination means 16 are of the electronic type and comprise sensor means 19 associated with the actuating devices 13 for the detection of the mutual position of the extreme portions 8a, 8b and display means 20 operationally connected to the sensor means 19.

Specifically, the sensor means 19 may be of the magnetic, inductive type or the like.

The display means 20 are of the type of a digital or analog display. The die 4 further comprises at least one counter- abutment surface 21 of the flexible type, associated with the plates 8 and adapted to define the bending seat 7 following the positioning of the extreme portions 8a, 8b.

In more detail, the counter- abutment surface 21 is interposed between the plates

8 and is intended to interact with the working tool 3 during the bending operation.

The operation of the die 4 according to the invention, installed on the press bending machine 1, is as follows.

For simplicity of description, the initial state is considered to be that in which the guidance elements 12 are both in the home position and the plates 8 in the parallel configuration, as shown in Figure 4.

In order to vary the conformation of the bending seat 7 while maintaining the plates 8 in the parallel configuration, the actuating devices 13 are actuated to displace the guidance elements 12 until they reach a working position in which they are equidistant from the transverse plane T.

The pairs of guidance portions 9, by interacting with the guidance elements 12, are moved close together and, in turn, the plates 8 are moved close together. (Figure 5)

To move the plates 8 to the inclined configuration, on the other hand, the actuating devices 13 are operated to displace the guidance elements 12 until they reach a working position where they are arranged at different distances from the transverse plane T.

In this way, one of the pairs of extreme portions 8a, 8b turns out to be approached with respect to the vertical plane V, while the other turns out to be spaced apart, at different mutual distances. (Figures 6 and 7)

The position determination means 16 allow determining the correct setting of the bending parameters by displaying the distance value between the pairs of extreme portions 8a, 8b.

At this point, the sheet-shaped element L is positioned at the point where the bending seat 7 is located and the working tool 3 is moved to interact with the bending seat itself and carry out the work.

In the inclined configuration, the interaction between the working tool 3 and the bending seat 7 allows carrying out the work of the sheet-shaped element L to obtain a bending of the conical type.

It has in practice been ascertained that the described invention achieves the intended objects, and in particular the fact is emphasized that the die for press bending machines according to the invention allows accurate adjustment of the plates and of the conformation of the bending seat.

The present die and the related press-bending machine are extremely versatile and are able to produce products of the conical type in a practical and precise manner, thanks to the presence of inclination variation means.

The movement assembly allows minimizing the working time and the risks for the safety of the operators.