GB2044660A - Cutting press for sheet materials - Google Patents

Abstract

A cutting press comprises a pair of rams 7 for actuating a movable platen 5 and a pressure equalizing device comprising a torsion bar (11) which is linkably connected to the ends of the platen. <IMAGE>

Description

SPECIFICATION Equalized-pressure cutting press for skins and like materials This invention relates to a cutting press for sheet materials, more particularly for skins, of the generally conventional type comprising a bottom platform intended for giving a rest to the materials to be cut, on which latter a properly outlined cutting punch is superposed, and a top pressing header which is commanded, by a couple of hydraulic jacks arranged laterally, to approach, whenever so desired, the underlying cutting punch to engage the latter so as to complete the cutting operation.

In the cutting presses of the kind referred to above there is the problem of equalizing the cutting pressure throughout the entire surface of the pressing header, thus offsetting the unbalances which are otherwise caused by possible different behaviours of the two jacks, in spite of the fact that they are evenly and simultaneously fed with fluid.

At present, solutions have been suggested for such a problem, which aim at uniformizing the behaviours of the two jacks from a strictly hydraulic standpoint, by throttling the feed to the most active ram and improving it, conversely, to the less active ram. However, the result is that the cutting pressure certainly becomes more uniform, but it is reduced relative to the maximum value which might be attained by the more active ram.

The object of the present invention, conversely, is to solve the problem outlined above so as to furnish to the entire pressing surface which can be obtained from the more active ram of the two.

According to the invention, this object is achieved by linkably connecting the two ends of the pressing header, upon which the respective hydraulic rams are active, to corresponding ends of a torsion bar.

The torsion bar, as it is apparent, permits that the maximum thrust impressed to either end of the pressing header by a possible more active ram may be transferred to the other end, the thrust being thereby equalized and thus the cutting pressure becoming more uniform and corresponding to the maximum magnitude the entire extension of the pressing header throughout.

A cutting press according to the invention is shown in order to have it better understood, by way of example only without limitation in the accompanying drawings, wherein: FIGURE 1 shows the structure of the cutting press in perspective view as viewed from the outside.

FIGURE 2 shows an axial cross-sectional view of the press, and FIGURE 3 shows a cross-sectional view of the press, taken along the line Ill-Ill of FIGURE 2.

The press depicted in the drawings comprises a fixed bottom platform 1, which is carried integrally by a base casing 2 and is intended to offer a resting surface to a sheet 3, of a material to be cut: a cutting punch or die 4, of any desired outline or contour, is superposed to the sheet material.

In a location above the fixed platform 1, and at an appropriately selected distance therefrom, a pressing header 5 is arranged, which is borne at the two side ends by a couple of sliding uprights 6 which are integral with one another and with the movable portions of two hydraulic rams 7 by means of a cross bar 8.

By the intermediary of connecting rods 9, which are pivoted at both ends, the cross-bar 8 is linkably connected to as many couples of gussets 10: these are rigidly connected to the ends of a torsion bar 11.

Torsion bar 11, in its turn, is connected eccentrically to fixed supporting hangers 13 at 12.

In FIGURES 1,2 and 3 the cutting press is shown in its rest position, with a wide gap left between the fixed platform 1 and the movable header 5 for introducing the material to be cut and the cutting punch(es).

To carry out the cutting operation, both rams 7 are commanded to extend so as to cause, via the crossbar 8, the descent motion of the two uprights 6 and thus of the pressing header 5 until abutting with a pressure the cutting punch 4. During such a step the torsion bar 11 ensures that the entire surface of the header 5 is subjected to the maximum pressure which can be obtained from either ram 7.

1. A cutting press for sheet materials, more particularly skins, comprising a fixed bottom platform and a top pressing header which is commanded through a couple of hydraulic rams acting upon side ends of the header, characterized in that said ends of the pressing header are linkably connected to corresponding ends of a torsion bar.

2. A cutting press substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Equalized-pressure cutting press for skins and like materials This invention relates to a cutting press for sheet materials, more particularly for skins, of the generally conventional type comprising a bottom platform intended for giving a rest to the materials to be cut, on which latter a properly outlined cutting punch is superposed, and a top pressing header which is commanded, by a couple of hydraulic jacks arranged laterally, to approach, whenever so desired, the underlying cutting punch to engage the latter so as to complete the cutting operation. In the cutting presses of the kind referred to above there is the problem of equalizing the cutting pressure throughout the entire surface of the pressing header, thus offsetting the unbalances which are otherwise caused by possible different behaviours of the two jacks, in spite of the fact that they are evenly and simultaneously fed with fluid. At present, solutions have been suggested for such a problem, which aim at uniformizing the behaviours of the two jacks from a strictly hydraulic standpoint, by throttling the feed to the most active ram and improving it, conversely, to the less active ram. However, the result is that the cutting pressure certainly becomes more uniform, but it is reduced relative to the maximum value which might be attained by the more active ram. The object of the present invention, conversely, is to solve the problem outlined above so as to furnish to the entire pressing surface which can be obtained from the more active ram of the two. According to the invention, this object is achieved by linkably connecting the two ends of the pressing header, upon which the respective hydraulic rams are active, to corresponding ends of a torsion bar. The torsion bar, as it is apparent, permits that the maximum thrust impressed to either end of the pressing header by a possible more active ram may be transferred to the other end, the thrust being thereby equalized and thus the cutting pressure becoming more uniform and corresponding to the maximum magnitude the entire extension of the pressing header throughout. A cutting press according to the invention is shown in order to have it better understood, by way of example only without limitation in the accompanying drawings, wherein: FIGURE 1 shows the structure of the cutting press in perspective view as viewed from the outside. FIGURE 2 shows an axial cross-sectional view of the press, and FIGURE 3 shows a cross-sectional view of the press, taken along the line Ill-Ill of FIGURE 2. The press depicted in the drawings comprises a fixed bottom platform 1, which is carried integrally by a base casing 2 and is intended to offer a resting surface to a sheet 3, of a material to be cut: a cutting punch or die 4, of any desired outline or contour, is superposed to the sheet material. In a location above the fixed platform 1, and at an appropriately selected distance therefrom, a pressing header 5 is arranged, which is borne at the two side ends by a couple of sliding uprights 6 which are integral with one another and with the movable portions of two hydraulic rams 7 by means of a cross bar 8. By the intermediary of connecting rods 9, which are pivoted at both ends, the cross-bar 8 is linkably connected to as many couples of gussets 10: these are rigidly connected to the ends of a torsion bar 11. Torsion bar 11, in its turn, is connected eccentrically to fixed supporting hangers 13 at 12. In FIGURES 1,2 and 3 the cutting press is shown in its rest position, with a wide gap left between the fixed platform 1 and the movable header 5 for introducing the material to be cut and the cutting punch(es). To carry out the cutting operation, both rams 7 are commanded to extend so as to cause, via the crossbar 8, the descent motion of the two uprights 6 and thus of the pressing header 5 until abutting with a pressure the cutting punch 4. During such a step the torsion bar 11 ensures that the entire surface of the header 5 is subjected to the maximum pressure which can be obtained from either ram 7. CLAIMS

1. A cutting press for sheet materials, more particularly skins, comprising a fixed bottom platform and a top pressing header which is commanded through a couple of hydraulic rams acting upon side ends of the header, characterized in that said ends of the pressing header are linkably connected to corresponding ends of a torsion bar.

2. A cutting press substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.