QUICK CONNECTION POR CONSTRAINING OPPOSED KECHANICAL PARTS ESPECIALLY IN PRESSES POR MAKING CERAMIC TILES Present state of the art In order to constrain parts of machines, accurately and safely, use is generally made of screws, bolts and other similar means. Where the constrained parts are subjected to high stresses and must frequently be disassembled and reassembled it is clear that the number of screws that must be handled takes far too much time and the work becomes in¬ compatible with, economic and competitive production. Pig. 1, for example, shows a system at present used in the presses for making ceramic tiles to connect the upper and lower dies or pads. It will be seen from the figure that situated between the upper plate (10), heated by elements (11) and the block (12) heated by elements (13), there are the lower pad (14) and the upper one (15) which, when pressure is applied, press on the tile (16) retained at its perimeter by a matrix die (17).

The upper pad is held to the upper plate by a serie s of cheese-headed screws ( 18 ) and the lower one is also fixed by cheese-headed screws (20) , but between the head of the screw and the pad there are two Belleville washers (25-26 ) . Due to the high pressure applied and to heating, the humi¬ dity contained in the clay of which the tile is made , evap¬ orate s leaving deposits of lime on the sides of the pad which leads to heavy wear and makes it ne cessary to replace them frequently . There are many of these pads to be periodically replaced on each press and numerous screws holding them in position

consequently the time needed for this replacement, with the press out of action, is long, making for higher costs of production and lower output.

If quicker means are resorted to, such as levers, clamps and the like, though this may make it quicker and simpler to disassemble and reassemble the opposed parts, there is generally an adverse effect on safety and accuracy. This present invention avoids the above drawbacks at the same time providing considerable advantages as will be ex- plained below.

Description of the Invention

Subject of the invention is a quick connection for constrain ing opposed mechanical parts especially the dies in presses for making ceramic tiles. In one of the parts to be constrained a pin is placed ha¬ ving a head which, with a slight amount of play, penetrates inside the tubular opening of the central body of a piston sliding in a cylindrical chamber placed in the other part to be constrained. Said piston is subjected to the effects of both an elastic means that tends to hold it away from the head and of a fluid,such as oil or the like, acting in the opposite dire_c tion. The tubular mouth of the central body of the piston, sliding with a slight amount of play in a ringwise seat at the front of the chamber, has radially placed holes passing through it in which small sized balls are lodged.

Ball diameter is less than the radius of the anular seat re¬ ferred to above, less pin radius, but greater than the ra- dius of said seat less that of the head.

Coaxial to said seat and above it there is a second anular

seat whose radius is greater than the diameter of the balls increased by the radius of the head. The effect of all the above is that, when the parts to be constrained are superimposed,and when the pin head is inside the tubular mouth of the piston to a point beyond the balls, fluid pressure having been reduced to nought or at any rate to a value below that createdby the elastic means, said elastic means, through the balls, exercises a pulling effect between the piston and the head of the pin sufficient to hold the above two parts together.

Contrarywise , when pressure greater than that of the elas¬ tic means is generated in the fluid, the piston moves to¬ wards the above mentioned head and the balls are carried to the position of the wider seat where there is sufficient space for them to abandon said head allowing the two con¬ strained parts to separate and to move away from each other which may also be done by remote control. Preferably the elastic means is in the form of a spring consisting of a pile of Belleville washers placed round the central body of the piston and reacting between it and the front of the chamber.

The anular seats in the front of the cylindrical chamber,in which the piston slides, are made in a bushing forming the front end of said chamber. The mouth of the fluid duct opens in the space created be¬ tween the piston and the bottom of the cylindrical chamber. The central body of the piston is connected to the same by means of a threaded pin which, by being screwed up or un¬ screwed, makes it possible to vary as desired the position of said piston in relation to the balls and therefore to vary the power of the constraint obtained by said elastic

means . hen a certain number of quick connections are positioned at suitable points on the parts to be constrained, theyare linked up to a single fluid generator in such a way as to obtain simultaneous action to all quick connections on the pair of bodies to be constrained and also, if required, to the connections on all pairs of bodies constrained by said connections in a machine. In presses for making ceramic tiles the pin with head is screwed into the so-called pad while the piston's cylindri. cal chamber is placed in the so-called block interposed be_ tween the pad and the ejection plate which also forms the bottom of said cylindrical chamber. Porward movement of the piston, pressed by the fluid, cau- ses at the same time pressure on the pad therefore detach¬ ing it from the block which gives considerable functional advantages.

Characteristics and purposes of the invention will be made even clearer by the following examples of its execution il lustrated by drawings. Examples of execution Pig. 2. Cross section of a quick connection between pad and block in presses for ceramic tiles. A threaded pin (2?) is connected to the pad (28). Contact i3 made on the head (29) of the pin by the balls

(30), lodged in the holes (31) of the tubular mouth (50) of the central body (32) connected to the head (34) of a pis¬ ton (37) by means of the threaded pin (33). Between the piston and the bushing (35) situated at the end of the cylindrical chamber (38) cut into the block (36)there is the pile (39) of Belleville washers. Vith slight play the mouth ( 50) slides inside the cylindrical

seat (48) of the bushing (35).

The guide ring (40) and oil seals (41 - 42) are mounted on the piston.

The packing (44) is interposed between the block ( 36 ) and the ejection plate (43) of the press to which said block is connected.

By means of a threaded connection (45) oil flows into the duct (46) and into the volume (47) between the piston and and the bottom (51) of the chamber (38). Operation

As shown in the figure the Belleville washers co ing into contact with the bushing (35) and therefore the block (36) exercise a pulling effect between the piston (37), the cen tral body (32), the mouth (50), the balls (30) and the head (29) of the pin (27) constraining said block against the pad.

When the pad (28) has to be replaced or when it is desired to separate it from the block, all that has to be done is to cause oil under pressure to flow into the volume (47). The oil will push the piston towards the head compressing the pile of Belleville washers.

The balls will move upwards simultaneously with the head and the pad, leaving the holes (31), pushed by the head it¬ self, and will take up a position in the anular seat (49) of the bushing, larger than the anular seat (48), allowing the pad to become detached from the block. Similar opera¬ tions done in the reverse order allow the block to be once more constrained to the said paid or to a new one. Advantages These are evident.

Time required for replacing pads is drastically reduced.

The press is better exploited, its working costs are thus

reduced which, also means lowering the cost of the finished product.

Control, whic may also be remote, through the fluid duct is extremely convenient and effective. In addition to constraining the pads in presses for making ceramic tiles, the quick connection here described may be used for an infinite variety of applications wherever op¬ posing parts have to be constrained in an entirely reliable manner. As applications of the invention have been described as ex¬ amples only not limited to these, it is understood that any equivalent application of the inventive concepts explained and any product made and/or operating according to the cha¬ racteristics of the invention will be covered by its field of protection.