Patent Application
20080299245
This invention relates to a unit for picking up ceramic products or the like, in particular ceramic products constituting parts of sanitaryware.
As is well known, ceramic sanitaryware (such as washbasins, toilet bowls, bidets, flush tanks and the like) is made by casting a fluid mixture (known as “slip” in the jargon of the trade, consisting of a ceramic body in aqueous suspension) in customary moulds with a porous structure, which may be divided into two or more parts.
The mould gives the article of sanitaryware the required shape and after a certain length of time (necessary to draw out a part of the water) the article is extracted from the mould in a solid form, known as “greenware” (still having a water content of between 17% and 20% by weight) and hence still subject to plastic deformation.
Some of these products, such as, for example, flush tank lids, because they are small in size and relatively simple in shape, are preferably made using individual moulds having two or more cavities located side by side so that a large number of products can be obtained in a single casting cycle.
In addition to that, the simultaneous extraction of these products from the mould (by opening it into its two half-moulds), an operation known as demoulding, is usually performed by a servo- or robot-controlled mechanical device equipped with an extraction tray mounted on an operating arm.
At present, the extraction tray consists of at least one operating pickup surface having at least one perimetric gasket for contact with the product and a central cavity for generating the vacuum necessary for picking up the product.
The mechanical device moves the gasket into contact with a surface of the product, activates the vacuum generating means to enable the product to be picked up and then transfers the product to a table, normally horizontal, where finishing operations are performed on it.
A product like the one mentioned above can be handled in two different ways: by its “noble” surface (that is to say, the surface that will be in view when the finished product is assembled) or by the opposite, less noble, surface that will be hidden by the other part of the flush tank.
At present, both these solutions have some disadvantages:
In other words, picking up the products in the green state by the noble surfaces has the obvious advantage of making subsequent operations simpler since the opposite surfaces (less noble) are usually flat and do not require particularly complex trays, but increases the risk of marking the noble surfaces and thus raises the number of end products that must be scrapped.
Picking up the product in the green state by the less noble surface, on the other hand, reduces the risk of marking the visible parts but requires a large number of accessories for subsequent operations, thus increasing production cycle times and costs and reducing production efficiency.
Moreover, whether a product is picked by its noble or less noble surface, there is always the risk of its sticking to the tray, after being demoulded, on account of the vacuum and the fact that the surface by which it is picked is wet. That means the product must be forcibly removed from the tray—for example reversing the direction of air flow or even manually—thus obviously slowing down product and creating the risk of damaging the product.
This invention has for an aim to overcome the above mentioned disadvantages by providing a unit for picking up ceramic products or the like which can hold the ceramic product securely and effectively by its noble surface and which has a low impact on the surface so as to reduce the risk of marking the surface.
Accordingly, this invention achieves this aim by providing a unit for picking up ceramic product or the like comprising the technical characteristics set out in one or more of the appended claims.
The technical characteristics of the invention, with reference to the above aims, are clearly described in the claims below and its advantages are apparent from the detailed description which follows, with reference to the accompanying drawings which illustrate a preferred embodiment of the invention provided merely by way of example without restricting the scope of the inventive concept, and in which:
With reference to the accompanying drawings, in particular
In particular, the unit, which is labeled 1 in its entirety, is used for extracting the product M from the respective half mould (not shown) after a known step of making the product M by casting a fluid mixture (known as slip in the jargon of the trade, consisting of a ceramic body in aqueous suspension) in customary moulds with a porous structure.
The unit 1 basically comprises:
The second chamber 7e is perimetrically delimited by the gasket 4: thanks to this structure, the above mentioned vacuum is applied to the opposite and facing surfaces of the wall 5 and of the surface S of the product M, respectively, when the gasket 4 comes into stable contact with the surface S in order to pick the product up.
The unit 1 further comprises a porous interface element 8 permeable to air located at least on the sealing gasket 4 and forming a surface that is more deformable than the gasket 4 and impermeable to liquids, or hydro repellent, interposed between the gasket 4 and the surface S of the product M when the above mentioned stable contact is made.
In other words, at least the contact gasket and, preferably, in the sealed vacuum area or second chamber 7e thus has placed over it a surface which is more deformable than it and which is porous so that air can be sucked in from the outside in order to hold the product M securely but without significantly deforming the surface of the product, especially if the contact surface is the “noble” surface, that is to say, the surface that remains in view when the product is finished and assembled.
Preferably, between the interface element 8 and the tray 2, there are interposed means 9 for locking/unlocking the element 8 to/from the tray 2 and in such a way as to position it on the gasket 4 and move it away from the gasket 4.
In one non-limiting embodiment, the interface element may be composed of a single deformable sheet 8, with suitable porosity and impermeability properties, covering the entire operating wall 5 of the tray 2 and forming a top (see
In
In an alternative embodiment, illustrated in
The movement of the sheet 8 (see arrow F11) enables the operating wall 5 to be covered and uncovered as required; when the operating wall 5 is covered, the sheet 8 is latched securely to a fastening element 12 located on the wall 2b on the opposite side of the tray 2 relative to the wall 2a.
In another alternative embodiment, illustrated in
These locking and unlocking means 9 may also constitute means 8t for tensioning the surface that comes into contact with the product M in order to prevent creases from forming on the surface of the sheet.
Obviously, other types of tensioning means 8t can be used instead of the locking means, such as for example, plates L for rigidly retaining the sheet 8 after it has been tensioned (see
Further, the sheet 8 is easy to wash, which means that optimum working conditions can be quickly and easily restored when the surface of the sheet 8 is dirtied by particles of the product M adhering to it.
A further characteristic feature of the interface element described above is that, since the gasket 4 protrudes partly, by a quantity H, from the operating wall 5 of the tray 2, the thickness K of the sheet 8 is sufficient to limit the difference in height H between the operating wall 5 and the protruding portion of the gasket 4 (see
In other words, the thickness K of the sheet 8 reduces or cancels the “step” created by the gasket 4 and allows the surface of the operating wall 5 to be made even more level, thereby eliminating any features that can cause deformation of the product M.
Furthermore, the operating wall 5 may be made as a single part with the tray 2 or it may be associated with the tray 2.
The operating wall 5 may be of the rigid type, equipped with a plurality of holes made in the wall 5 itself in such a way as to enable the two chambers 7, 7e to communicate with the vacuum source, as mentioned above. In this case, the operating wall 5 may be made from metal netting.
Alternatively, the operating wall 5 may be made of a porous material obtained, for example, by sintering or polymerization so that, in this case too, the two chambers 7, 7e can communicate with the vacuum source.
Lastly, the operating wall 5 may be advantageously shaped to match the surface S of the product M to be picked up, thus further improving the performance of the pick-up unit.
A pick-up unit made as described above fully achieves the aforementioned aims thanks to the interface element between the product and the gasket, which allows:
The invention described above is susceptible of industrial application and may be modified and adapted in several ways without thereby departing from the scope of the inventive concept. Moreover, all details of the invention may be substituted by technically equivalent elements.
| Number | Date | Country | Kind |
|---|---|---|---|
| BO2007A000385 | May 2007 | IT | national |
