EP0256570B1

EP0256570B1 - Press frame

Info

Publication number: EP0256570B1
Application number: EP87201240A
Authority: EP
Inventors: Roberto Nassetti
Original assignee: NASSETTI ETTORE SpA
Current assignee: NASSETTI ETTORE SpA
Priority date: 1986-07-16
Filing date: 1987-06-29
Publication date: 1990-12-19
Anticipated expiration: 2007-06-29
Also published as: IT8621151A0; IT1196506B; EP0256570A1; DE3766773D1; ATE59161T1; ES2019370B3; BR8703701A

Abstract

A press frame (10), particularly for ceramic molding materials, includes two walls (11,12), being interspaced and parallelely interconnected by a pair of press plates. Said walls (11,12) and said press plates (13,14) are rigidly mounted in the direction of the horizontal axis (x), while being free to buckle along the other two axes (Y and Z).

Description

The present invention relates to an improved press mounting particularly but not exclusively suitable for ceramic molding products as tiles and the like.
Press mountings of a known type are in general structurally formed by a pair of parallel walls, respectively front and back wall, interconnected at a suitable distance one from the other, as to locate a space of containment, between them, a space for containing the various press gears including a work compartment to whom to enter through lined up large openings obtained inside of the very walls.
The connection between said front and back walls is obtained by means of frames composed of elements welded between them and the very walls.
A completely rigid structure is so located that is to say that it is by no means subject to strain, suffering from the serious drawback of being subject to breakings, especially when asymmetrical loadings are driven to it, due to an anomalous way of working of the press, what may,even frequently happen. Such breakings are primed mostly in correspondance to the welding areas.
The purpose of the present invention is that of obviating to the above mentioned drawback realizing a press mounting not completely rigid capable of buckling when subjected to asymmetric anomalous loads avoiding in such a way that said loads discharge only in a predetermined zone of the mounting with the result of priming dangerous breakings.
Said purpose is achieved, according to the invention, by realizing a press mounting, particularly for molding ceramic materials, of the type including a pair of hollow walls respectively front and back wall, that are interspaced and interconnected parallelely by means of a pair of boards respectively lower and upper board, characterized by that said walls and said boards are rigidly assembled along a direction perpendicular to the walls, while being free to buckle in a direction parallel to the walls.
Preferably said boards have an external shape equal to each other and among them and show each a structure in general U shaped with wings that protrude from a base protruding beyond said wings with teeth that lean upon the respective parallel horizontal planes of the walls that are also equal to each other and are kept interspaced by said wings.
The structural and functional characteristics of the invention and its advantages as compared with prior art will even more clearly result understandable from the following description, referred to the enclosed drawings, that show an example of a press mounting realized according to the same invention. In the drawings:

figure 1 is a front elevation view showing said press mounting;
figure 2 is a section taken along the trace II-II of figure 1;
figure 3 is a section taken along the trace III-III of figure 1;
figure 4 is a section taken along the trace IV-IV of figure 1;
figure 5 is a section taken along the trace V-V of figure 1;
figure 6 is a view along the arrow F of figure 4; and figure 7 is a detail.

With reference to the drawings, the subject mounting is complessively indicated by 10 and it is structurally formed by four main pieces that, according to the invention, are rigidly assembled along the axis X, while free to buckle along the other two axes Y and Z.
More exactly, said four main pieces include a pair of walls 11, 12 respectively front and back wall, and a pair of boards 13, 14, lower and upper board respectively.
As clearly seen by figures 1 and 2 of the drawings, said walls 11 and 12 are equal to each other and show each a generally rectangular shape having a central opening 15 to enter into the pressing zone.
The tables 13, 14 are also equal to each other and show each a generally "U" shaped structure with wings 16 extending from a base 17 protruding beyond said wings 16 with teeth 18. According to the known technique, the upper table 14 has a seat 32 for a press head (not shown).
From figure 2 of the drawings it is seen how said teeth 18 of bases 17 lean on respective parallel horizontal planes 19 of walls 11, 12, that are kept suitably interspaced by said wings 16.
Among teeth 18 and planes 19 it is interposed a steel sheet 20.
The perfect centering of boards 13,14 relatively to the axis Z is ensured by terminal flanges 21 that are bolted to teeth 18 and that abut to the ends of the casting floors 19 (figure 7).
The constrain among the walls 11,12 and the boards 13,14 is ensured (figure 1-4) by means of a threaded sleeve 22 having a crest clearance through lined up holes 23,24, respectively obtained into walls 11,12 and into the wings 16 and tightened on the place by means of a lock nut 25. As seen by the detail of figure 3, footstep bearings 26,27 are respectively located among the walls 11,12 and the wings 16, and among these last and the lock nut 25.
In addition (figure 1,4 and 6), from walls 11,12 are stretching supports 28 on which are leaning, by the interposition of bucket springs 29, relevant teeth 30 integral to the wings 16 of the tables 13,14.
As clearly seen from figures (1,2 and 5), the walls (11 and 12) are leaning and fixed on a multi-layer base frame indicated at 31.
It is so realized according to the invention a structure for "ring-press" composed by 4 main pieces (11,12,13 and 14) rigidly assembled on a axis (X) and free to strain along the other two axes (Y-Z) at disposal.
The assembly results transversally rigid along the axis "X"; the rigidity is ensured by the four boltings obtained by means of the threaded sleeves 22 and the relevant lock nuts 25.
The footsteps bearings 26,27, mounted on the four boltings axis allow the sliding of the pieces 13,14 relative to the pieces 11,12 along the axis "Y" up to a maximum clearance "g" existing among the tube sleeves 22 and the holes 23,24.
The pieces 13 and 14 transmit the compression load to the pieces 11,12 through the teeth 18 by the interposed sheet 20.
Said sheet 20 has the function of absorbing in the resilient phase the buckling difference under the loading of the pieces 13 and 14 relative to the pieces 11,12.
The centering relative to the axis "Z" is ensured by the flanges 21.
The mainteinment of the geometry according to the axis "Z" and "Y" is ensured by the adjustable load springs 29 recoverable if uncalibrated.
Said loading is normally calibrated between 4 and 8 times the statical loadings (weights) of the pieces composing the structure.
The invention mounting shows the following main advantages;
The four main pieces composing it can be obtained by different technological procedures in view of the strains that they have to bear; in fact in the pieces 13 and 14 the pressing strength generates stretchings on the three axes (double deflection or plate-effect). The fused steel structure by which these pieces are generated does not have oriented fibres but it is spatially homogeneous, thus resulting more suitable for absorbing the above mentioned stretchings.
In the pieces 11,12 the pressing strain generates stretchings according to the main axes "Y" and "Z", being the pieces 11,12 obtained by rolled steel and thus having oriented fibres.
The logical application of the loading along the fibers leads to the most adequate solution for absorbing the above mentioned stretchings.
The four main pieces shape composing the structure is very simple and thus there are no stretchings in the raw semi-finished generated.
After their generation, said pieces are not submitted to tratments capable of modifying their structure, but they are worked out only to take off the metal chip.
The assembling ensures the perfect machine- geometry even under the pressing load.
The loadings transmission takes place among a piece and the others by means of free bearings, thus each singular particular becomes strained according to its resilient characteristics without influencing the resilient characteristics of the adiacent piece. Are thus eliminated the conditions of rigid constraint (dove tail) and thus are eliminated the points of indeterminable statical system classics of welded structures.
So there is the possibility of utilizing materials of a different type based on loads. Such a coupling may not be compatible with other assembling systems.

Claims

1. A press mounting, particularly for molding ceramic materials, of the type including a pair of hollow walls (11, 12) respectively front and back walls, that are interspaced and parallelely connected by means of a pair of boards (13, 14) bottom and top boards respectively, characterized by that said walls (11, 12) and said boards (13, 14) are rigidly assembled along a direction perpendicular to the walls (11-12), while being free to buckle in a direction parallel to the walls (11-12).

2. A press mounting according to claim 1, characterized by that said boards (13, 14) have an external shape equal to each other said show each a generally U shaped structure with wings (16) extending from a base (17) protruding beyond said wings (16) with teeth (18) that lean on the relevant horizontal parallel (19) planes of the walls (11, 12) that are also equal to each other and are kept interspaced by said wings (16).

3. A press mounting according to claim 2 characterized by that to said teeth (18) are fixed terminal flanges (21) that abutt against the ends of planes (19), being so ensured the perfect centering of the boards (13, 14) relative to the vertical axis (Z);

4. A press mounting according to claim 2, characterized by that the constraint among the walls (11, 12) and the board (13, 14) is ensured by a threaded sleeve (22) passing with clearance through the lined up (23, 24) holes obtained inside the walls (11, 12) respectively and into the wings (16), and tightened in place by a lock nut (25), footstep bearings (26, 27) being interposed respectively among the walls (11,12) and the wings (16), and among these last and the lock nut (25), from said walls (11,12) extending supports (28) on which lean, by the interposition of bucket springs (29), relevant teeth (30) solid to the wings (16) of the boards (13,14).