EP3194117B1

EP3194117B1 - Machinery for the machining of ceramic articles

Info

Publication number: EP3194117B1
Application number: EP15788191.3A
Authority: EP
Inventors: Mario Corradini
Original assignee: Ancora SpA
Current assignee: Ancora SpA
Priority date: 2014-09-16
Filing date: 2015-09-15
Publication date: 2018-06-27
Anticipated expiration: 2035-09-15
Also published as: CN107107311A; ES2687440T3; WO2016042467A1; PL3194117T3; EP3194117A1

Description

Technical Field

The present invention relates to a piece of machinery for the machining of ceramic articles and by-products thereof.

Background Art

These manufactured articles, mainly used in construction, can be made with different ceramic materials which are selected by their different chemical-physical characteristics and mechanical properties.
As a first approximation one may distinguish among unglazed porous paste ceramic materials, such as bricks or earthenware, glazed porous paste ceramic materials, such as majolica, and, finally, compact paste ceramic materials, such as stoneware and porcelain.
In any case these materials are known to be machined with machines providing for the use of specific abrasive tools.
Generally, these tools are disc-shaped elements moved by a special motor. These motors operate at approx. 2800 rpm and are directly connected to the tool associated with a relative spindle.
Alternatively they can be connected to the tool by means of an inverter that can vary the spindle revs up to a maximum of approx. 5000 rpm.
The rotation of the tool allows different types of machining of the input material such as grinding, roughing, cutting, etc.
The strong friction generated by the action of the tool on the manufactured article causes the tool itself to overheat so as to require a control of the temperature by means of appropriate cooling systems.
Depending on the cooling process there are two types of machining: dry processes and wet processes.
The latter are necessary when the tool overheating level is such as to make any dry cooling ineffective.
In dry processes cooling occurs by blowing air directly on the tool. For the removal of the waste material from the work area it is sufficient to provide for a traditional aspiration system.
In wet processes cooling occurs by spraying water or other liquids on the tool.
In this case, water combines with waste material, thus producing a waste sludge that must be disposed of in compliance with the criteria established by the law in force.
Traditional machinery used for dry cooling usually provides differentiated cooling systems for each tool. In particular, to each motor of each tool is connected a cooling unit that takes advantage of part of the work of the motor itself to compress the cooling air to send to the tool via a dedicated connection tube.
In traditional machines which use conventional tools such as grinding wheels, etc. dry cooling is possible for the machining of porous paste ceramic material which, being less resistant, causes lower tool overheating.
Dry cooling can also be used in the machining of porcelain stoneware if this takes place at reduced speed which, on the other hand, involves a consequent reduction in the removed material and therefore in productivity.
For more resistant materials, as is the case of high speed machining of porcelain stoneware, a wet process must be used, resulting in the production of waste sludge to be handled and disposed of.
A first drawback of traditional machinery used for dry cooling is linked to the fact that at conventional speeds (approx. 2800 rpm) the machining of very resistant materials such as those with compact paste (e.g. porcelain stoneware), involves overheating of the tool and of other mechanical parts, such as the spindle, which are impossible to control with dry cooling. It is therefore necessary to use water or other liquids resulting in the production of waste sludge the handling and disposal of which involve a considerable expenditure in terms of time and resources.
Furthermore, the machinery of known type provides a differentiated cooling of the tool and of the mechanical parts which support it in rotation, with consequent high construction and maintenance complexity.
Another drawback of known machinery is linked to the fact that, since each tool is cooled using part of the work produced by the respective motor, a loss of efficiency of the motors themselves is produced with a consequent increase in energy consumption of the production process.
A further drawback of known machinery is linked to the fact that the tools, directly connected to the motor or by means of an inverter, fail to achieve higher speeds than 5000 rpm. This entails the need, in order to achieve desired production volumes, to use a high number of tools with consequent high energy consumption, high investment costs and large overall dimensions. EP1932617A1 and DE4015241A1 teach machinery according to the state of the art.

Description of the Invention

The main aim of the present invention is to provide a piece of machinery which allows an efficient, easy to manufacture and affordable tool cooling.
Within this aim, one object of the present invention is to simplify, with respect to the machinery of known type, the cooling of the tool and of the mechanical parts which support it in rotation.
Another object of the present invention is to provide a piece of machinery for the machining of ceramic articles which allows to increase the spindle revolution number so as to use tools that achieve top efficiency at significantly higher speeds than those used to now in the ceramic sector.
Another object of the present invention is to provide a piece of machinery which allows using dry processes also in the machining of high resistant ceramic material.
A further object of the present invention is to provide a piece of machinery which allows to obtain an increase in efficiency and energy savings in the manufacturing process.
Another object of the present invention is to provide a piece of machinery which allows to overcome the mentioned drawbacks of the prior art within the ambit of a simple, rational, easy, effective to use and low cost solution.
The objects stated above are achieved by the present machinery for the machining of ceramic articles and the like having the characteristics of claim 1.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become better evident from the description of a preferred but not exclusive embodiment of a piece of machinery for the machining of ceramic articles and the like, illustrated by way of an indicative, but non-limiting, example in the accompanying drawings, wherein:

Figure 1 is a side elevation view of the machinery according to the invention;
Figure 2 is a side sectional view of a detail of the machinery according to the invention;
Figure 3 is a front view of a detail according to the invention.

Embodiments of the Invention

With particular reference to such illustrations, reference number 1 globally designates a piece of machinery for the machining of ceramic articles and the like.
The piece of machinery 1 for the machining of ceramic articles or the like has a support frame 2 with which is associated at least a machining device 3 which comprises a motor element 4 associated with the support frame 2, a tool 5 for the machining of ceramic articles, a motor shaft 10 connected to said motor element 4 and supporting the tool 5 in rotation.
The machinery 1 also comprises motion transmission means 8, 9, 11 for transmitting motion from the motor element 4 to the tool 5.
Alternative embodiments are not ruled out wherein the tool 5 is directly connected to the motor element 4.
The support frame 2 comprises a base structure 6 able to hold the machining device 3 in a predetermined working position.
In the embodiment shown in figure 1 the machining device 3 is fixed to the base structure 6 so that the tool 5 can work at a height from the ground coinciding with that of the line of forward movement 7 of the ceramic material to be machined.
The tool 5 is operable in rotation around a respective axis and is kinematically connected to the motor element 4.
The motion transmission means 8, 9, 11 comprise at least a first pulley 8 associated with the motor element 4, at least a second pulley 9 associated with a shaft 10, supporting the tool 5 in rotation and a belt element 11 which mutually connects the first pulley 8 to the second pulley 9.
In this way, by operating the motor element 4, the rotary motion generated by the same is transmitted from the first pulley 8 to the second pulley 9 through the belt element 11 and, therefore, from the second pulley 9 to the tool 5 through the shaft 10.
Conveniently, the second pulley 9 has a smaller diameter than the first pulley 8 so as to enable the tool 5 to rotate at a higher speed than the speed of the motor element 4.
Advantageously, the diameter of the second pulley 9 is sized so that the tool 5 can reach a speed between 5000 and 7000 rpm, i.e. the appropriate speed to allow tools made with very resistant material to work in the most efficient manner.
In the present embodiment, in fact, the tool 5 is the type of a diamond wheel.
In this way, high resistant ceramic materials, such as porcelain stoneware, can be machined without using wet cooling processes.
These types of tool, in fact, keep their hardness and resistance characteristics even at high temperatures, without jeopardizing the quality of the machining process.
As illustrated in Figure 2, the machining device 3 comprises a containment body 12 for containing the shaft 10.
In the present embodiment, the body 12 is a substantially prismatic casing able to contain the shaft 10.
In particular, between the body 12 and the shaft 10 is defined a gap 13 intended to contain cooling air and having at least an inlet opening 14 and at least an outlet opening 15 for such cooling air.
In particular, cooling air enters the gap 13 so as to lap and therefore cool the mechanical parts in motion within the body 12, such as the spindle or bearings that support the shaft 10 in rotation, preserving them from excessive and exhausting overheating due to the mechanical action they are subjected to during operation.
Still with reference to Figure 2, there is an outlet tubular element 16 associated with the outlet opening 15 and able to convey air from the gap 13 to the tool 5. In particular, the tubular element 16 comprises a first extremity associated with the outlet opening 15 and a second extremity associated with a nozzle 17 able to increase the output speed of air.
More particularly, the outlet section of cooling air defined by the nozzle 17, which is oriented so as to direct the exiting air jet towards the tool 5, is smaller than the transit section defined by the tubular element 16.
In the embodiment illustrated in the figures, the machinery 1 comprises a plurality of machining devices 3 arranged in series along the line of forward movement 7 of the material to be machined identified with arrow 7.
According to the invention, the machinery 1 has cooling means 18, 19, 22, 23 of the machining devices 3.
The cooling means 18, 19, 22, 23 provide a common manifold 18 and compression means 19, where the common manifold 18 has an inlet port 20 able to receive cooling air from the compression means 19 and a plurality of outlet ports 21 of the cooling air.
In the present embodiment, the compression means 19 are made up of a compressor unit able to send pressurized air into the common manifold 18. Alternative embodiments are not ruled out wherein the compression means 19 are formed by a turbine or a turbo-compressor unit or the like.
Each of the outlet ports 21 is connected to the inlet opening 14 of a respective machining device 3 so as to send cooling air into the respective gap 13.
The cooling means 18, 19, 22, 23 also comprise an inlet conveyor element 22 and a plurality of outlet conveyor elements 23.
The inlet conveyor element 22 is associated with the inlet port 20 so as to connect the common manifold 18 to the compression means 19.
Each of the outlet conveyor elements 23, on the contrary, is able to connect one of the outlet ports 21 to a respective inlet opening 14, so as to convey cooling air from the common manifold 18 to the machining device 3.
In particular, the inlet conveyor element 22 has a larger section than the outlet conveyor elements 23.
The sizing of the sections of the conveyor elements 22, 23 is such as to ensure a sufficient air flow to each machining device 3.
Alternative embodiments are not ruled out wherein the cooling means 18, 19, 22, 23 are the type of oil cooling means.
The operation of the present invention is as follows.
The compression means 19 send compressed air to the common manifold 18 through the inlet conveyor element 22.
Air in the common manifold 18, in turn, is distributed into the machining devices 3 by means of the outlet conveyor elements 23, entering in the corresponding gaps 13.
Subsequently, by means of the tubular element 16, air is blown on the tool 5 through the nozzle 17. The latter, the outlet section of which is smaller than the section of the tubular element 16, increases the outlet speed of air taking advantage of the well-known "Venturi effect".
At the same time, the motor element 4 rotates at approx. 2800 rpm and the first pulley 8 also rotates with it. By means of the belt element 11 the rotary motion is transferred to the second pulley 9 which, having a smaller diameter than the first pulley 8, will rotate at a faster speed, approx. 5000/7000 rpm. Being the tool 5 associated with the second pulley 9 by means of the shaft 10, it will also rotate at the same speed as the second pulley 9.
It has in practice been found how the described invention achieves the proposed objects and in particular the fact is underlined that the machinery allows efficient cooling of the tools, using the same air to cool the tools and mechanical parts, such as the spindle, which support it in rotation, thereby leading to significant energy savings.
Therefore, the machinery using this type of tool allows for a cooling of the same by means of dry processes also in the machining of high resistant ceramic material.
Finally, thanks to the use of the above-mentioned cooling means it is possible to achieve an increase in efficiency and energy savings of the production process, given that one single compressor, or turbine, or the like provides for cooling each tool and the mechanical parts of the respective machining device.
The machinery, thanks to the use of the motion transmission means described above, allows to rotate the tool also at higher speeds than the rotation speed of the motor that operates it.
For this reason it is possible to use tools made of very resistant material (such as diamond grinding wheels) and which require, in order to achieve top efficiency, higher rotation speeds than 2800 rpm of the motors used.
The transmission means making the subject of the present invention thus enable to considerably reduce, compared to machinery of known type, the number of tools used, production capacity being the same, thereby reducing energy consumption, investment costs and overall dimensions of the machine.

Claims

Machinery (1) for the machining of ceramic articles or the like, having a support frame (2) and at least a machining device (3) associated with said support frame (2) and comprising:
- at least a motor element (4) associated with said support frame (2);
at least a tool (5) which can be operated in rotation around a respective axis for the machining of ceramic articles;
a shaft (10) connected to said motor element (4) and supporting said tool (5) in rotation;

- a body (12) for containing said shaft (10);
cooling means (18, 19, 22, 23) of said tool (5);
characterized by the fact that said cooling means (18, 19, 22, 23) comprise:
at least a gap (13), interposed between said body (12) and said shaft (10) and intended to contain cooling air,

said gap (13) having an inlet opening (14) and an outlet opening (15) for the cooling air and said cooling means (18, 19, 22, 23) comprising a tubular element (16) associated with said outlet opening (15) and able to convey the cooling air towards said tool (5).
Machinery (1) according to one or more of the preceding claims, characterized by the fact that said tubular element (16) comprises a first extremity associated with said outlet opening (15) and a second extremity associated with a nozzle (17) able to increase the output speed of said air.
Machinery (1) according to one or more of the preceding claims, characterized by the fact that it comprises a plurality of said machining devices (3).
Machinery (1) according to claim 3, characterized by the fact that said cooling means (18, 19, 22, 23) of said machining devices (3) have at least a common manifold (18) having an inlet port (20) able to receive the cooling air from compression means (19) and a plurality of outlet ports (21) of the cooling air, each of which is connected to the inlet opening (14) of a respective machining device (3) to send the cooling air into said gap (13).
Machinery (1) according to one or more of the preceding claims, characterized by the fact that said cooling means (18, 19, 22, 23) comprise an inlet conveyor element (22) associated with said inlet port (20) and able to connect said common manifold (18) to said compression means (19) and a plurality of outlet conveyor elements (23) each of which is able to connect one of said outlet ports (21) to a respective inlet opening (14), so as to convey the cooling air from said common manifold (18) to said machining device (3), said inlet conveyor element (22) having a larger section than said outlet conveyor elements (23).
Machinery (1) according to one or more of the preceding claims, characterized by the fact that it comprises motion transmission means (8, 9, 11) from said motor element (4) to said tool (5).
Machinery (1) according to one or more of the preceding claims, characterized by the fact that said motion transmission means (8, 9, 11) comprise at least a first pulley (8) associated with said motor element (4), at least a second pulley (9) associated with said shaft (10) and at least a belt element (11) able to connect said first pulley (8) to said second pulley (9).
Machinery (1) according to one or more of the preceding claims, characterized by the fact that said second pulley (9) has a smaller diameter than said first pulley (8).
Machinery (1) according to one or more of the preceding claims, characterized by the fact that said tool (5) is the type of a diamond wheel.