Forming Punching Apparatus

The invention concerns machine tools for working workpieces and/or sheets metal and in particular concerns a forming punching apparatus that can be associated with a punching machine for performing forming and/or deformation workings on workpieces.

Punching machines are known that are provided with a punching apparatus, called punching head, which supports and moves linearly along a working axis a tool that acts on the workpiece, typically a sheet metal, cooperating with an underlying die or counter-tool. The die is generally fixed to a working surface of the punching machine that supports the workpiece.

A first type of punching tools comprises punches or punch inserts capable of cutting, shearing, punching the workpiece to make holes, slots, variously shaped through openings or separation contours, division cuts or capable of making deep-drawings facing the working surface (i.e., downwards). The respective dies comprise cavities having a shape almost complementary to that of the respective punches so as to receive the punches while the working is being performed.

A second type of tool comprises forming or deformation tools capable of plastically deforming the workpiece to make deep-drawings of different shapes and sizes, bridges, slits, etc., which project from the opposite side of the working surface (i.e., upwards).

The forming process can be static, keeping the workpiece stationary during working, or dynamic, moving the workpiece, typically to make elongated deformations such as steps, ribs, slits, etc. Since the deformation of the workpiece is opposite to the working surface (upforming) the dies comprise lower forming tools having a shape complementary to the shape of the upper forming tools and also movable linearly with the upper forming tools and in opposite direction. The forming tools typically comprise wheels, rollers, discs, having a suitably shaped external profile and rotatable about an axis orthogonal to the working axis. In the single-tool punching heads, the tool is mounted on a support element, called spindle, which is driven linearly along and rotary about the working axis by respective actuators. The linear movement along the working axis in the two opposite directions allows performing working and return strokes of the tool in the punching process. The rotation movement about the working axis allows the punching tool to rotate and change its angular orientation (indexing) to perform different cuts or punchings on the workpiece.

The multi-tool punching heads comprise a plurality of punching tools and a beating element, called ram element, which is moved linearly along the working axis and acts on the selected punching tool, by imparting to the latter the kinetic energy and the linear movement necessary to perform the working on the workpiece.

The punching tools or punches are housed in a tool holder device that is fixed to the punching head and is arranged between the ram element and the workpiece. The tool holder device generally comprises a rotatable drum in which the tools are slidably housed and arranged circumferentially about the drum rotation axis.

Each multi-tool punching head also comprises a multiple die, that is, provided with a plurality of dies in a number equal to the number of the respective punches and rotatable about the working axis to allow the angular orientation of the punches.

The known multi-tool punching heads cannot however mount the forming tools, as the dies are not able to receive a plurality of lower forming tools, and in particular they are not able to move such tools along and about the working axis in order to select the lower forming tool, orient it angularly, and then lift it towards the upper forming tool against the workpiece. US 2019/366411 discloses a set of punches and dies and a selecting apparatus which are configured to perform forming workings on sheet materials. The selecting apparatus can be associated with a punching machine to select a punch and a die, which must be engaged by a beating element of the punching machine, and to force or allow the movement of the unselected dies away from the sheet material so as not to impact or damage the latter while it is being worked.

An object of the present invention is to improve the known punching apparatuses, in particular the forming punching apparatuses.

Another object is to carry out a punching apparatus provided with a plurality of upper and lower forming tools that can be selected, angularly oriented and activated quickly and efficiently.

A further object is to carry out a punching apparatus that allows a plurality of different forming or deformation workings to be optimally performed, with the workpiece stationary or moved.

Another object is to provide a forming punching apparatus having a simple and compact structure and small dimensions.

These and other objects are achieved by a punching apparatus according to one or more of the claims reported below.

With reference to, a punching apparatusaccording to the invention is shown that is associable with a punching machine, of known type and not illustrated, and is arranged to perform forming and/or deformation workings on workpieces, in particular sheets metal.

The punching apparatus, illustrated in section in, comprises a punch holder unitprovided with a plurality of upper forming tools or forming punches, for example three, and a die holder unitprovided with a plurality of lower forming tools or forming dies, for example in number equal to that of the upper forming tools.

The punch holder unitcomprising an upper support bodyrotatable about a working axis X, a punch holder bodyrotatably connected to the upper support bodyand arranged to slidably house the plurality of upper forming toolsand an upper beating element. The upper beating elementis slidably supported by the upper support bodyand is movable parallel to the working axis X to selectively interact with an established upper forming toolso as to partially push it outside the punch holder bodyso as to interact with the underlying workpiece, as better explained in the following description.

The die holder unitcomprising a lower support bodyrotatable about the working axis X, a die holder bodyfixed to the lower support bodyand arranged to slidably house the plurality of lower forming tools, and a lower beating element.

The lower beating elementis housed in the lower support bodyand is movable linearly along, and rotatably about, the working axis X to selectively interact with an established lower forming tool. The lower beating elementis movable linearly between an non-operative position A, in which it is locked in rotation by first stop meansand does not rotate together with the lower support body, an operative position B, in which it is connected by second stop meansto the lower support bodyso as to rotate together with the latter about the working axis X, and a second operative position C in which the lower beating elementpushes the established lower forming toolpartially outside the die holder bodyso as to interact with the overlying workpiece.

With particular reference to, the die holder bodycomprises a plurality of lower seatseach of which is adapted to receive a lower tool holder elementto which a respective lower forming toolis associated. Each lower tool holder elementcomprises, in particular, a first endconfigured to receive and support the respective lower forming tooland a second endsuitable to interact with the lower beating element.

In the illustrated embodiment, the lower forming toolscomprise shaped wheels or rollers that are mounted on respective lower tool holder elementsand are idly rotatable about respective first rotation axes Y, nearly orthogonal to the working axis X.

The die holder unitfurther comprises a plurality of lower thrust elementsthat are slidably connected to the die holder bodyand arranged to support respective lower tool holder elementsof the lower forming tools. Each lower thrust elementcan be abutted and moved along the working axis X by the lower beating elementso as to move the respective lower tool holder elementand therefore the corresponding lower forming tool, as better explained in the following description.

Each lower thrust elementhas a substantially prismatic shape and comprises two opposite and parallel abutment walls, in particular almost orthogonal to the working axis X, and intended respectively to abut the second endof the lower tool holder element(to support the lower tool holder element and the lower deformation toolassociated therewith) and to be abutted by the lower beating element.

The lower beating elementis slidable within a cavityof the lower support bodyand has a main bodyof almost cylindrical shape.

The lower beating elementis slidably connected to the die holder bodyby a first guide pinhaving a first upper endfixed to the die holder bodyand a second lower endthat is slidably coupled to a seatof the lower beating element. The first guide pinis substantially coaxial to the working axis X.

First elastic meansare interposed between the lower beating elementand the die holder bodyand are configured to elastically keep said lower beating elementspaced apart from said die holder bodyin the non-operative position A.

The first elastic meanscomprise, for example, a respective cylindrical helical spring mounted on the first guide pin.

The lower beating elementalso comprises a first abutment portionthat extends from the main bodyand is configured to abut an established thrust elementso as to move the corresponding lower forming tool.

The die holder unitcomprises second elastic meansinterposed between each lower thrust elementand the die holder bodyand configured to elastically keep said lower thrust elementsspaced apart from the die holder bodyin a respective non-operative position E when not abutted and pushed by the lower beating element. Each lower thrust elementis slidably connected to the die holder bodyby one or more, for example two, second guide pinson which the first elastic meansare mounted that comprise respective cylindrical helical springs.

The first stop meanscomprise a first tab configured to engage a longitudinal groove, in particular parallel to the working axis X, made on an external wall of the lower beating element. The first tabis for example connected to support meansof the punching machine on which the die holder unitis mounted.

The second stop meanscomprise a second tab fixed to the second support bodyand configured to engage the longitudinal grooveof the lower beating element.

The punching apparatusalso comprises driving means,acting on the lower beating elementto move it linearly in the operative positions B, C along a thrust direction F, in particular towards the overlying punch holder unit.

In particular, driving means,abut and act on a second abutment portionof the lower beating elementopposite to the first abutment portion

In the illustrated embodiment, the driving means,comprise a first linear actuatoradapted to move the lower beating elementbetween the non-operative position A and the first operative position B and a second linear actuatoradapted to move the lower beating elementbetween said first operative position B and the second operative position C.

Alternatively, the driving means may comprise a single linear actuator capable of controllably moving the lower beating elementbetween the non-operative position A and the first operative position B and between the first operative position B and the second operative position C.

In particular, the driving means,can be integrated into the punching machine on which the punching apparatusis mounted.

The die holder bodycomprises an upper walladapted to abut and support a workpiece. In the upper wallthere are the plurality of lower seatsin which the lower tool holder elementsto which the respective lower forming toolsare associated are housed. With particular reference to, the punch holder bodyof the punch holder unitcomprises a plurality of upper seatseach of which is adapted to receive a respective upper thrust elementand an upper tool holder elementto which a corresponding upper forming toolis associated. Each upper thrust elementis interposed between the upper beating elementand the respective upper tool holder element.

In particular, each upper thrust elementcomprises an abutment endconfigured to interact with a respective beating portionof the upper beating elementand a connecting endthat is coupled to the upper tool holder element.

Each upper thrust elementis slidably engaged in a first guide portionof the respective upper seatwhile the upper tool holder elementconnected thereto is slidably engaged in an underlying second guide portionof the upper seat.

The upper thrust elementcomprises an upper part, which includes the abutment end, having an almost cylindrical pin shape and a lower part, which includes the connecting endhaving a prismatic shape. The cylindrical wall of the upper parthas a longitudinal flatteningthat prevents the rotation of the upper thrust elementabout its longitudinal axis inside the first guide portionof the respective upper seat.

In the illustrated embodiment, the upper forming toolscomprise respective wheels or shaped rolls or discs, mounted on the upper tool holder elementsand idly rotatable about respective second rotation axes Yalmost orthogonal to the working axis X.

The punch holder unitcomprises a closing discfixed to a lower portion of the punch holder bodyand provided with through openingsthat allow the upper forming toolsto exit.

The punch holder unitalso comprises an abutment elementslidably connected to the upper support bodyand to which the upper beating elementis fixed. The abutment elementis configured to interact with a ram element, of known type, of the punching machine on which the punching apparatusis mounted.

The abutment elementis slidably connected to the upper support bodyby one or more, for example four, third guide pinson which third elastic meansare mounted that comprise respective cylindrical helical springs.

The third elastic meansare interposed between the abutment elementand the upper support bodyand are configured to elastically keep said abutment elementspaced apart from said upper support bodyin a respective non-operative position G, when not pushed by the ram element of the punching machine.

The upper support bodyalso comprises a through seatsuitable for receiving and slidably guiding the upper beating elementhaving for example the shape of a cylindrical pin.

The operation of the forming punching apparatusof the invention comprises in an initial step selecting the upperand lowerforming tools to perform a required forming or deformation working on a workpiece, for example a sheet metal, which is positioned on the upper wallof the die holder body elementof the die holder unit.

In order to select the upper forming tool, for example, the upper support bodyis rotated about the working axis X with respect to the punch holder body, which is kept stationary so that the upper beating elementis aligned and superimposed on the selected upper forming tool. More precisely, after selection, the respective beating portionof the upper beating elementfaces the abutment endof the upper thrust elementconnected to the upper tool holder elementthat houses and supports the selected upper forming tool.

Alternatively, the punch holder bodycan be rotated about the working axis X with respect to the upper support bodywhich is kept stationary.

Upper support bodyor punch holder bodyis rotated with respect to each other about the working axis X by suitable first driving means, of known type and not described in further detail, of the punching machine on which the punching apparatusof the invention is mounted.