More specifically, the present invention relates to a resilient element which has been particularly designed for application in mechanical presses, between the pressing plate and die plate thereof.

The mold springs conventionally comprise two different types of springs.

A first type of spring comprises the so- called wire springs, which are made by coiling a wire material and are provided with particular operating properties.

At first, these springs have a very small length in their fully compressed condition, which, the free length of the spring being the same, will provide a maximum deflection in comparatively small spaces.

A second main property of the wire springs is their long useful life, also depending on the available spring materials and on the stresses applied for long times to said springs.

In this connection it should be apparent that a long useful life represents a very important parameter since a failure of a spring would compel the user to perform complex and long replacing operations in which the mold must be disassembled and then properly reassembled.

Actually, it should be also considered that

the mentioned molds are usually provided with a plurality of springs and, a failure of a single spring would involve a malfunction and failure of the overall mold which is an expensive article of manufacture.

For increasing the useful life of said springs, the spring forming wire has usually a laminated construction, in order to provide a cross- section contour of substantially trapezium configuration, thereby providing an axial extension much smaller than the cross extension of the spring.

The second type of springs comprises synthetic rubber springs, made by molding methods.

These springs are usually much more rigid than the wire springs, and allow much smaller deflections or strokes and slower operating cycles; these springs are very expensive, but have a useful life much greater than that of a wire spring.

SUMMARY OF THE INVENTION Thus, the aim of the present invention is to provide a resilient element for molds allowing to combine the properties and advantages of the above mentioned two types of springs, in order to provide a mold resilient element of high useful life.

This aim is achieved by the present invention which specifically relates to a resilient element for molds, having a long useful life, said resilient element comprising at least a wire spring, and being characterized in that said wire spring is operatively coupled to further resilient means made of a material different from that forming said wire spring.

More specifically, said resilient means

comprise a first and second resilient bodies, each of which is engaged with one of the end portions of said wire spring.

According to a preferred embodiment of the present invention, the first and second resilient bodies, made of a material which is different from that forming the wire spring, are each provided with a fist and second cylindric portions, which are arranged inside a respective end portion of said wire spring.

According to a further preferred embodiment of the present invention, said first and second resilient bodies are each provided with a coil profile, formed by contouring the resilient body, said coil or helical profile defining a seat for engaging therein the last turn of the wire spring.

Finally, the first and second resilient bodies, made of a material different from that forming the wire spring, are made of a synthetic rubber material.

The invention provides the following advantages with respect to the prior art.

At first, the provision of said synthetic rubber resilient bodies, operating as plug elements with respect to the end portions of the wire spring, will allow to omit any grinding operations for properly grinding the end portions of the spring, which grinding operations are very expensive and scarcely controllable.

A second advantage of the invention is that the provision of said synthetic rubber resilient bodies will allow the spring end turns to slightly rotate, thereby discharging the most part of the dangerous stresses concentrated on said end turns, and

this owing to the capability of the rubber resilient bodies to be slightly deformed by twisting.

Moreover, the mentioned resilient bodies will absorb any vibrations occurring along the spring body and will allow to open the last spring turn, the closure of which would cause a great deformation of the wire cross-section as well as possible cuts of the second-last turn of the spring by the cutting tool.

A further function of the mentioned synthetic rubber resilient bodies is that they can be easily colored in order to identify, by a suitable color code, the loading class of the spring, thereby obviating the requirement of coloring the wire spring itself.

Finally, the inventive resilient bodies would allow to greatly reduce the planarity and perpendicularity tolerances while allowing a very unexpensive product.

Thus, the invention will provide a resilient element for molds having an useful life which is much greater than that of prior wire springs, and this at a competitive cost.

BRIEF DESCRIPTION OF THE DRAWINGS Further advantages and characteristics of the invention will become more apparent from the following detailed disclosure, given by way of an illustrative but not limitative example, with reference to the accompanying drawings, where: Figure 1 is a side exploded view of the mold resilient element according to the present invention; Figure 2 is a side view of the mold resilient element shown in Figure 1; and

Figure 3 is an axonometric view of one of the resilient bodies of the mold resilient element according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following disclosure reference will be made to some preferred embodiments of the present invention, which are illustrated as a mere example of several possible variations of the invention.

Figure 1 is an exploded side view illustrating the mold resilient element, having a long useful life, according to the present invention, which has been generally indicated by the reference number 1.

The resilient element 1 comprises a wire spring 2, the end portions of which are coupled respectively to a first and second resilient bodies, respectively indicated by the reference numbers 3 and 4, each of which engages with one of said end portions of the wire spring 2.

In particular, the wire spring 2 is formed by a wire element having a substantially trapezoidal cross-section.

Each of said resilient bodies 3 and 4 is provided with a first and second cylindric portions, respectively indicated by the reference numbers 5 and 6.

The first cylindric portion 5 is engaged inside a portion of the spring wire 2, at one of said end portions of said wire spring 2; likewise, the second cylindric portion 6 is engaged inside a further portion of the spring wire 2, at the opposite end portion of said wire spring 2.

Moreover, each said resilient body 3 and 4 is provided with a coil or helical profile or contour 7 and is formed by suitably contouring or shaping the resilient bodies.

The coil contour 7, in particular, defines a seat for engaging therein the last turn 8 of the wire spring 2.

In order to better understand the operation of the invention, it should be pointed out that the first and second resilient bodies 3 and 4 are both made of a material different from that forming the wire spring 2.

More specifically, the first and second resilient bodies 3 and 4 are made of a synthetic rubber material.

The first and second resilient bodies 3 and 4 are applied to the respective end portions of the wire spring 2, by engaging said bodies in said respective cylindric portions 5 and 6, thereby providing a pair of plug-like elements; this configuration of the resilient element 1 according to the present invention will allow to suitably combine the properties of the wire springs with those of the synthetic rubber springs.

The specifically designed configuration of the synthetic rubber resilient bodies 3 and 4, having a helical or coil profile 7, would allow to engage the last turn 8 of the wire spring 2 without requiring any grinding operations on the end portions of said spring.

The provision of the resilient bodies 3 and 4 will allow the end turns of the wire spring 2 to slightly rotate, thereby discharging the most part of

the dangerous stress concentrating thereat.

This effect is obtained owing to the capability of the resilient bodies 3 and 4 to deform under twisting.

The resilient bodies 3 and 4, moreover, will absorb the vibrations along the body of the spring.

Said resilient bodies, finally, would also allow to open the last turn 8 of the wire spring 2, the closure of which would cause great deformations of the wire cross section, as well as frequent cuts of the second-last turn by the cutting tool.

A preferred embodiment of the present invention provides that the wire spring 2 is encompassed by a protective sheath.

This protective sheath is made by coating by a plasticizing method, the wire of the spring 2 by using a highly resilient filamentary construction synthetic material.

The provision of said protective sheath will prevent fragments of the wire spring 2, in a case of a failure, from being ejected into portions of the mold in which said spring is assembled, to cause a failure of the mold.

From the above disclosure it should be apparent that the invention fully achieves the intended aim.

Of course, the disclosed mold resilient element is susceptible to several variations and modifications coming within the scope of the invention as claimed.