EP1932619B1

EP1932619B1 - An apparatus for distressing solid objects comprising a drum

Info

Publication number: EP1932619B1
Application number: EP20070023922
Authority: EP
Inventors: Tomasino Fontana
Original assignee: Mf Di Fontana Tomasino; M F DI FONTANA TOMASINO
Current assignee: Mf Di Fontana Tomasino
Priority date: 2006-12-12
Filing date: 2007-12-11
Publication date: 2012-08-08
Anticipated expiration: 2027-12-11
Also published as: ITRE20060150A1; EP1932619A1

Description

The invention relates to an apparatus for distressing solid objects, such as for example ceramic glazes, masonry, stone, wood; and also articles made of cast materials such as bronze and stainless steel.
The distressing operation gives the piece a particular surface abrasion, and be used for example for deburring cast pieces, obtaining smooth surfaces free of burrs; or, if a deeper operation is performed, for giving a surface a particular surface roughness, an effect which is especially appreciated in covering materials, which gain a worn and antiquated appearance because of the lack of sharp edges it leaves, and for the "lived-in" look of the surfaces produced.
This lived-in or aged look is obtained in nature by a long period spent on a river bed.
In an industrial context, to artificially reproduce this effect apparatus are used such as grinding ball mills in the ceramics field for pulverising frits, or glazes based on solid vitreous or ceramic materials.
The prior art includes using mills substantially constituted by a trunco-cylindrical drum, quite broad, which is partially filled with a mixture of spheres, or balls, made of a hard material (such as silicon, or treated alubit) and water, and rotated according to the axis of symmetry of the cylinder for a certain time, such as to reduce the pieces introduced therein to power thanks to the cyclic motion of revolution, contact and rubbing of the materials contained.
For more fragile pieces it is preferred to fill the drum with water, dispensing with the presence of spheres or balls made of a hard material, and proceeding to rotate the drum by means of an external motor, for a certain time.
In this situation the reciprocal contact of the pieces inside the drum causes erosion of the external surfaces of the pieces, thus obtaining the distressed effect.
The product to be treated is introduced into the drum through a sealed hatch and distressed for a certain time, perhaps multiples of ten minutes, according to the characteristics of the product (harder or less hard), and the surface effect desired.
The known apparatus for distressing exhibit some drawbacks.
Firstly, experience of this type of working with mills has shown that working long pieces, such as for example rods, baseboards, bars, leads to considerable waste or rejects, due to the breakage of the pieces caused by the particular revolution movement to which the pieces are subjected. Secondly, in known distressing mills the working times for each cycle are generally rather long, thus limiting production potential.
GB 685 711 A describes a barrel for barrel polishing. The system is egg-shaped and is adapted to be rotated about an axis of rotation which is inclined at a small angle to the axis of the barrel. In particular, the system is formed by two half-barrels wherein each of the half-barrel has a spindle boss 48 cast integral with it and strengthening webs 49. The spindle bosses 48 are cast in such a position on the half-barrels so that when the two half barrels are secured together, the bosses 48 are aligned on a line which intersects at a small angle of $16 \frac{1}{4} •$
with the major axis of the ellipsoid.
The system described in GB 685 711 A has therefore an elaborate shape which is difficult to be manufactured. Moreover, the structure of the system, and, in particular, the connection between the barrel and the support structure by means of the spindle bosses 48 and the strengthening webs 49, beside being difficult to be manufactured, does not guarantee high stability so that particular care must be taken in the selection of the rotation speed and of the load of the barrel.
The aim of the present invention is to obviate the above-mentioned drawbacks, by providing an apparatus which is able to distress correctly, even operating on solid bodies in which the length is prevalent with respect to the other two dimensions, with cycles having a particularly contained duration.
The aims are attained according to the indications of claim 1 and the relative dependent claims, which are appended to the present description.
The invention will be more fully understood from the description that follows of an example of application thereof, illustrated by way of nonlimiting example in the accompanying figures of the drawings, in which:

figure 1 is a schematic lateral view of an apparatus made according to the invention, in the loading position of the material to be distressed;
figure 2 is the same apparatus in which the drum is rotated by 180° with respect to figure 1.

With reference to the figures of the drawings, 1 denotes in its entirety an apparatus for distressing solid pieces, made according to the invention.
2 denotes a sturdy base frame superiorly provided with two rolling supports 6 on which a drum 3 rotates according to an axis 10 thereof.
The axis 10 is preferably arranged horizontally.
The drum 3 is constituted by a trunco-cylindrical central part 4, and by two heads 5.
The internal wall of the drum 3 is covered with a known anti-abrasion material, such as for example panels made of a hard polyurethane.
The cylindrical part 4 is provided with a central axis of symmetry 11, which does not coincide with the rolling axis 10 of the drum 3.
The two axes 10 and 11 form an angle α, a value of which depends on the type of the material being worked.
Consequently the supporting pivots of the drum 3 on the supports 6 are applied on the heads 5 asymmetrically, i.e. not coinciding with the central of the head.
By way of indication, for distressing fragile materials or pieces, the value of the angle α is comprised between 10 and 20 degrees; while for materials or pieces which are not fragile, such as for example cast pieces to be deburred, or for the milling of ceramic glazes, the value of angle α is comprised in the range from 30 to 40 degrees.
Motors 7 are provided, powered by an electric motor 8 controlled by a known-type electronic card which can vary the rotation speed continuously and freely.
A hatch 9 of known type is located on the wall of the drum 3 for introducing/evacuating the contents thereof, which are introduced discontinuously.
Functioning is as follows.
After introducing the material to be distressed and closing the hatch 9, the drum is rotated according to the horizontal axis 10. As this axis does not coincide with the axis of symmetry of the drum 3, an oscillation of the drum 3 is produced which superposes the rotation movement.
Figure 2 shows the position of the drum 3 after half a revolution: note that in this position the inclination of the drum is inverted with respect to the start position.
An oscillating movement of the drum follows during rotation thereof, which enables the above-cited aims to be attained.

Claims

An apparatus for distressing solid products, constituted by a drum (3) developing along an axis of symmetry (11), by first and second heads (5) extending from opposite end portions of said drum (3), by first and second pivots coupled with first and second rolling supports (6), respectively, superiorly provided on a sturdy base frame (2), the longitudinal axis of symmetry of said first and second pivots thus defining the rotation axis (10) of said drum (3), so that the longitudinal axis of symmetry of said first and second pivots extends along a direction defining a predefined angle (α) with said axis of symmetry (11) of said drum (3) so that the rotation axis (10) of the drum (3) is not coincident with said axis of symmetry (11) of said drum (3), said drum (3) being further provided with a sealed hatch (9) for loading and unloading;
characterized in that:
the drum (3) is trunco-cylindrical, in that

each of said first and second heads (5) has a truncated oblique cone shape, and in that

said first and second pivots extend from end portions of said first and second heads (5), respectively, opposite to said trunco-cylindrical drum (3).
The apparatus of claim 1, characterized in that the rotation axis (10) and the axis of symmetry (11) form a reciprocal angle (α) which is comprised between 10° and 40°.
The apparatus of any one of claims 1 or 2, characterized in that motors (7) causing the rotation of the drum (3) are powered by an electric motor controlled by an electronic card which can vary a rotation speed of the drum (3) as desired.
Use of an apparatus according to one of the claims 1 to 3 for distressing solid objects, such as ceramic glazes, masonry, stone, wood.