WO2023144435A1

WO2023144435A1 - System for fixing cutting dies in die rotary cutting machines

Info

Publication number: WO2023144435A1
Application number: PCT/ES2023/070045
Authority: WO
Inventors: Ramón SERRA OBIOL; Jordi Puig Vargas
Original assignee: Comercial Industrial Maquinaria Carton Ondulado, S.L.
Priority date: 2022-01-27
Filing date: 2023-01-27
Publication date: 2023-08-03
Also published as: ES1289947Y; ES1289947U

Abstract

The clamping device comprises a pin (1) movable relative to an internally hollow plunger (2) which is axially movable relative to an outer cylinder (3) by the introduction of a fluid under pressure, the outer cylinder (3) being closed by a cover (4) provided with a through hole through which the pin (1) is slidable, first elastic means linked to a relative movement of the pin (1) with the plunger (2) and second elastic means linked to a relative movement of the plunger (2) with respect to the outer cylinder (3), the first elastic means having a coil spring (5) located inside the plunger (2). The second elastic means comprise a plurality of coil springs (7) which are radially distributed in holes drilled in the peripheral area around the pin (1) and which are in contact with the cover (4). Thanks to these features, it is possible to reduce the length of the pin without reducing the force it exerts on the die, making it suitable for cylinders with a small diameter. The fact of having a plurality of springs allows the sum of forces to be equal to that which would be exerted by a single spring, while at the same time allowing a greater relative deformation.

Description

DEVICE FOR HOLDING DIES IN DIE CUTTING MACHINES

DESCRIPTION

OBJECT OF THE INVENTION

The purpose of this application is to register a die holding device for a cardboard sheet die-cutting machine.

More specifically, the invention proposes the development of a die-holding device for laminar material die-cutting machines, being suitable for devices that are provided with a retractable bolt that acts with various elastic means.

BACKGROUND OF THE INVENTION

In rotary die-cutting machines, the material to be cut, for example, cardboard for the manufacture of boxes, moves between a die-holding cylinder and a counter-die cylinder or rotating anvil, so that for each turn of the cylinders the die strikes on the counter-die and performs a cut or deformation on the cardboard sheet. To prevent the die from being damaged by impact, the surface of the counter-die is provided with a polyurethane coating.

Different systems are known to hold the rotary dies on the die-holder cylinder. A known fastening system is disclosed in document ES 2 155 334 which describes a plurality of retractable pins (inserts) actuated by an actuator device, housed inside a hollow body fastened to the die-holding cylinder. This system, which has proven to be effective for many years, also requires having the maximum number of inserts to guarantee maximum firmness in the die clamping on the die cylinder.

In the case of die cylinders with a relatively small diameter, the The number of inserts is limited by the size of the cylinder where the retractable bolt is housed, which does not allow the arrangement of two capiculate inserts, the dimensional limitation being due to the length of the bolt and the internal elastic means provided for the extension and retraction of the retractable bolt.

In addition, the applicant is not currently aware of an invention that has all the characteristics that are described in this specification.

DESCRIPTION OF THE INVENTION

The present invention has been developed in order to provide a clamping device for dies that is configured as a novelty within the field of application and solves the aforementioned drawbacks, also providing other additional advantages that will be evident from the description. which is attached below.

It is therefore an object of the present invention to provide a device for holding dies in laminar material die-cutting machines, being of the type that comprises a pin that can be moved with respect to an internally hollow plunger that is axially movable with respect to an external cylinder by the introduction of a pressurized fluid, the outer cylinder being closed by a cover provided with a through hole through which the bolt can slide, first elastic means linked to a relative movement of the bolt with the plunger and second elastic means linked to with a relative movement of the plunger with respect to the outer cylinder, the first elastics having a helical spring located inside the plunger. In particular, the invention is characterized by the fact that the second elastic means comprise a plurality of helical springs radially distributed in holes made in the peripheral zone around the bolt and which are in contact with the cover.

Thanks to these characteristics, it is possible to reduce the length of the pin without reducing the force it exerts on the die, thus being suitable for cylinders with a small diameter. The fact of having a plurality of springs allows the sum of forces to be equal to that exerted by a single spring such as the system shown in figure 2, while allowing a greater relative deformation. On the other hand, in figure 3 the arrangement of two devices diametrically opposed to each other can be seen, thanks to the larger dimensions that the device can adopt due to the arrangement of multiple helical springs.

Another no less important advantageous aspect is the fact that the force exerted by the bolt against the die that is mounted on the die-holder cylinder can be easily varied, simply replacing the rigidity of the helical springs or by varying their number internally. of the plunger, that is, fewer springs can be used compared to the number of holes provided for their accommodation.

According to another constructive aspect of the invention, the underside of the cover has a plurality of radially distributed cavities that are designed to partially house the helical springs.

Preferably, the retractable bolt includes in its head an area with a larger diameter configured to hold a die to a die-holding cylinder.

In a preferred embodiment, the cap and the outer cylinder may be fixed by means of a plurality of radially distributed holes and pins.

Additionally, there are sealing means present between the outer cylinder that are in contact with the outer face of the cylinder that forms the plunger.

The fastening device described represents, therefore, an innovative structure with structural and constitutive characteristics unknown until now for the purpose for which it is intended, reasons that, together with its practical utility, provide it with sufficient grounds to obtain the privilege of exclusivity that is requested. .

Other characteristics and advantages of the holding device object of the present invention will become evident from the description of a preferred, but not exclusive, embodiment, which is illustrated by way of non-limiting example in the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is an exploded perspective view of an embodiment of the die clamping device according to the present invention;

Figure 2.- Is a sectional elevation view of a fastening device of the prior art installed in a die-holding cylinder;

Figure 3.- Is a sectional elevation view of a pair of clamping devices according to the invention installed in a die-holding cylinder; and

Figures 4a-d.- They are elevation views that show the different functional positions adopted by the fastening device of the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT

In view of the aforementioned figures and, in accordance with the numbering adopted, a preferred embodiment of the invention can be seen in them, which comprises the parts and elements indicated and described in detail below.

Furthermore, the terms first, second, third and the like in the description and in the claims are used to distinguish between similar items and not necessarily to describe a sequential or chronological order. The terms may be interchanged in appropriate circumstances and embodiments of the invention may operate in sequences other than those described or illustrated herein.

Furthermore, the terms top, bottom, top, bottom, and the like in the description and claims are used for descriptive purposes and not necessarily to describe relative positions.

The die clamping device is intended to be used in die-clamping systems. support for cylinders that are part of laminar material stamping machines, comprising a bolt (1) that can be moved with respect to an internally hollow plunger (2) that is axially movable with respect to an external cylinder (3) internally hollow by the introduction of air pressurized through an inlet (10) located at the bottom of the outer cylinder (3) which is connected to an external supply source of conventional pressurized air (not shown).

The bolt (1) includes in its head (101) an area with a larger diameter configured to hold a die to a die-holding cylinder.

The outer cylinder (3) is closed at the top by a cover (4) that has an outer contour adapted to the radius of curvature of the die-holder cylinder (14), which is provided with a central through hole (40) through which it can be extended. and retract the bolt (1).

In addition, the cover (4) has a seat (41) at one end of the central through hole (40) provided to position the area with the largest diameter of the bolt.

In order to execute the different relative movements of the bolt (1) and the plunger (2), the clamping device comprises first elastic means linked to a relative movement of the bolt (1) with the plunger (2) and second elastic means (described in greater detail later) linked to a relative movement of the plunger (2) with respect to the outer cylinder (3). The first elastic means consist of a helical spring (5) located inside the plunger (2). The fixing and guiding of the helical spring (5) is carried out by means of the provision of an intermediate element (6) with a general shape of a bowl in which one end of the bolt (1) is threaded. Said intermediate element (6) has a protruding rim (60) that acts as a stop for one end of the helical spring (5).

With particular reference to the second elastic means, they comprise a plurality of helical springs (7) that are radially distributed in holes (20) made in the peripheral area around the bolt and that are in contact with the cover. Going back to the cover (4), its underside has a plurality of radially distributed cavities that are designed to partially house the helical springs (7).

As can be seen in figure 1, the cover (4) and the outer cylinder (3) are fixed by means of a plurality of holes (31) made and radially distributed in a protruding rim (30) of the outer cylinder (3) for allow the coupling of some corresponding pins (8).

In order to prevent leaks of pressurized air inside the outer cylinder (3), there are sealing means present between the outer cylinder that are in contact with the outer face of the cylinder that forms the piston (2). More specifically, such sealing means consist of an O-ring (9) housed in a diametrical groove present on the inner face of the outer cylinder (3).

To prevent the rotary movement of the piston (2) with respect to the outer cylinder (3), there are means that essentially consist of an elongated pin (11) that has a smaller diameter than the helical springs (7) so that it is housed inside one of the helical springs (7), and a blocking element (12) that can be coupled to the pin through a hole (42) made in the cover (4) (see figure 1).

Figure 4a shows the device in a first position in which the bolt (1) is in a rest position, that is, the area with the largest diameter of the bolt (1) is located in the seat (41). of the cover (4), and the second elastic means being in a fully extended condition. In figure 4b the plunger (2) is displaced above by the introduction of compressed air into the chamber (32) through the inlet (10), where the bolt (1) is in its extended position in such a way which is beyond the die (13) without being in contact with it and the second elastic means are partially compressed. On the other hand, in figure 4c the interior of the outer cylinder (3) is again devoid of pressurized air, where the plunger (2) is slightly displaced downwards and the bolt (1) is in a position such that holds the die (13) against the die-holder cylinder (5). Finally, in figure 4d the The interior of the outer cylinder (3) is supplied with compressed air and the bolt (1) is in a retracted position with respect to the plunger (2) as the punch (13) is at that point without a through hole, the first elastic means being in a fully compressed condition.

The details, shapes, dimensions and other accessory elements used in the manufacture of the fastening device of the invention may be conveniently replaced by others that do not depart from the scope defined by the claims included below.

Claims

1. Device for holding dies in laminar material die-cutting machines, comprising a bolt that can be moved with respect to an internally hollow plunger that is axially movable with respect to an external cylinder by the introduction of a fluid under pressure, the external cylinder being closed by a cover provided with a through hole through which the bolt can slide, first elastic means linked to a relative movement of the bolt with the plunger and second elastic means linked to a relative movement of the plunger with respect to the outer cylinder, having the first elastic means a helical spring located inside the plunger, characterized in that the second elastic means comprise a plurality of radially distributed helical springs in holes made in the peripheral area around the bolt and that are in contact with the cover .

2. Die clamping device according to claim 1, characterized in that the underside of the cover has a plurality of radially distributed cavities that are intended to partially house the coil springs.

3. Die holding device according to claim 1, characterized by the fact that the bolt comprises in its head, an area of greater diameter configured to hold a die to a die-holding cylinder.

4. Die clamping device according to any of the preceding claims, characterized in that the cover and the outer cylinder are fixed by means of a plurality of radially distributed holes and pins.

5. Die holding device according to any of the preceding claims, characterized by the fact that it includes sealing means present between the outer cylinder that are in contact with the outer face of the cylinder that forms the plunger.

6. Die clamping device according to any of the claims above, characterized by the fact that it includes anti-rotation means configured to prevent the rotary movement of the piston with respect to the cylinder.

7. Die clamping device according to claim 6, characterized in that the anti-rotation means consist of an elongated pin that is housed inside one of the helical springs, and a blocking element that can be coupled to the pin through a drilled hole in the lid.