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(11) | EP 1 547 741 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 158(3) EPC |
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| (54) | MOULDING FRAME FOR PRESSING TILES, COMPRISING A MAGNETIC BLADE-FIXING SYSTEM |
| (57) The present invention relates to a moulding frame for the pressing of tiles with
magnetic securing of blades intended to allow a quick interchange of the blades with
a high level of safety. This invention makes use of electro-permanent magnets or of
electromagnets in the securing of the blades (3) incorporating appropriate means for
eliminating the magnetic field for withdrawing and replacing the blades. This invention
has a position of the magnets adapted to the position of the blade and the loads which
it receives, be this position horizontal or vertical. |
OBJECT OF THE INVENTION.
[0001] The present invention refers to a mould frame for pressing tiles with magnetic securing of blades intended to allow quick interchange of blades with a high level of safety.
[0002] This invention is characterised in the use of electro-permanent magnets or of electromagnets in the securing of the blades incorporating appropriate means for suppressing the magnetic field for the withdrawal and replacement of the blades.
[0003] This invention has a position of the magnets adapted to the position of the blade and the loads it receives, be this position horizontal or vertical.
BACKGROUND OF THE INVENTION.
[0004] The production of tiles makes use of punches with high application pressures intended to compress the ceramic or clay material between two surfaces, one surface being visible and the other intended to be attached to the surface to be covered.
[0005] There are two punches, a mobile upper one and another lower down. The upper punch descends until reaching the lower punch on which the clay or ceramic material is deposited. The upper face, to which the upper punch is applied is the hidden face of the tile, and the lower face in contact with the lower punch gives the form to the visible face of the tile.
[0006] Laterally, the material is determined by the presence of some blades secured to a frame. The form of the blades is that which the edge of the tile will adopt.
[0007] These blades are subjected to high pressures and frictional forces for which reason they are made from very strong materials which undergo heat treatments to increase the hardness particularly on their surface.
[0008] These blades usually have a shoulder which results in a raised area in the tile so that in their production and during transport over the conveyor belt, through mutual contact, they are not blunted.
[0009] In addition to the shoulder, toward the contact edge, the surface is inclined favouring the ejection of the tile. This inclination is known in the trade as "tirada".
[0010] Given the high wear the blades suffer, it is necessary to interchange them. The known means of securing are screwed unions which require a substantial time for replacement.
[0011] The blades must also be changed when it is necessary to change the production to make use of different peripheral configurations.
[0012] The operation of removing and mounting the blades is carried out with the machine stopped and therefore it is lost time for production.
[0013] The present invention makes use of a magnetic means of securing which greatly reduces the time for replacement of blades since release from the magnetic field and the restoration thereof are immediate.
[0014] Although magnetic means are well-known for securing plates of top punches, they are not known in frames whose mechanical requirements for their immobility, action opposing the effects of the gravitational field and the presence of the blades make the problem from the engineering point of view require a new design with different mechanical solutions.
DESCRIPTION OF THE INVENTION.
[0015] The present invention, in relation with a mould frame for pressing tiles with magnetic securing of blades, overcomes the substantial times for replacement of the blades which occur with the frames known until now.
[0016] In this invention, the frame is provided with magnetic means for securing the blades. The frames based on screwed means for securing simply include a seating surface on which are to be found the threaded perforations which accept the screws.
[0017] This invention includes seats for the blades, the means of securing magnetically, and also the devices which allow control of the magnetic flux to permit the blades to be removed and new or recovered ones mounted.
[0018] The magnetic securing is achieved through the application of a magnetic field which attracts the blades. This magnetic field can be obtained either by means of an electro-permanent magnet or otherwise by means of an electromagnet.
[0019] In either case it is necessary to have control in two situations: a first one for maintaining the magnetic field which assures the securing of the blades during production, and a second one for eliminating the magnetic field to release of the blades.
[0020] In the case of making use of an electro-permanent magnet, the use of any magnetisable material is sufficient, since by application of a high intensity magnetic field, the magnetic domains present at microscopic level are pointed in the same direction assuring as from that moment the securing of the blades without maintaining the external excitation.
[0021] The combined use with electro-permanent magnets which channel the magnetic flux appropriately, allows two possible states: the activated electro-permanent magnet forcing the magnetic field generated by the magnetisable material to reach the blade, or the magnet inhibited wherein the magnetic field of the magnetisable material is deviated before reaching the blade without exercising any securing action whatsoever.
[0022] An alternative means of securing makes use of an electromagnet. In this case the excitation in the coil which generates the magnetic field has to be maintained constantly during the whole time that the blades are attached to the frame.
[0023] With the use of electro-permanent magnets, the change from one state to the other is possible by acting through an excitation coil which only requires a short period of actuation to change the magnetic polarity of the magnetisable material.
[0024] Once the blades have been changed, it is necessary to excite the magnetisable material again to restore the magnet responsible for the force securing the blades.
[0025] The operation of changing blades with an electromagnet merely requires removal of the current which excites the electromagnet so that the latter releases the blades. When changed, it is necessary to re-apply the current which maintains the electromagnet active.
[0026] The increased complexity in the construction of the electro-permanent magnet is justified by its greater level of safety since the securing action remains in the event of a possible power supply failure.
[0027] The blades can be located in two positions with respect to the frame, either horizontal establishing support on an upper horizontal face, or vertical covering the side of the internal window of the frame.
[0028] In either of the two situations the blade can be one only, or be made up of different elementary blades which progressively cover each of the faces.
[0029] In this second situation, it is possible to interchange only the blades which suffer greatest wear, it being even possible to turn it round if it is symmetrical and allows reversibility.
[0030] In either case, the means of magnetic coupling are always behind the surface supporting the blades against the frame in housings intended for this purpose.
[0031] In the case of using an electro-permanent magnet, a magnetic core is located between ferrite or neodyne elements with their common poles (for example the N poles) directed toward the core. This assembly for magnetic coupling is housed in a recess in the frame, being separated from its bottom by means of a tablet of magnetisable material for example alnico.
[0032] This tablet is surrounded by an excitation coil which magnetises the alnico tablet in one direction or the other. When the polarisation coincides with that of the ferrite elements, the flux generated by this tablet extends to the exterior of the recess reaching the blades since it encounters opposition with the flux of the ferrite elements. However, when the polarisation is the opposite, the flux finds continuity with that generated by the ferrite elements whereby the magnetic circuit established does not reach the blades.
[0033] When the magnetic means of coupling make use of an electromagnet, the latter is formed by a coil housed in a recess in the form of a channel having a closed directrix. The recess establishes a closed circuit wherein is lodged the coil which generates the magnetic field in the event of a current flowing establishing in turn a magnetic field which flows through the core which is defined on the inside of the circuit.
DESCRIPTION OF THE DRAWINGS.
[0034] The present descriptive specification is supplemented with a set of drawings which illustrate, but in no way restrict the preferred embodiment of the invention.
[0035] Figure 1 shows a first embodiment of the invention which makes use of vertical blades and electromagnets.
[0036] Figure 2 shows a second embodiment of the invention which makes use of horizontal blades and electromagnets.
[0037] Figure 3 shows a first embodiment of the invention which makes use of vertical blades and electro-permanent magnets.
[0038] Figure 4 shows a second embodiment of the invention which makes use of horizontal blades and electro-permanent magnets.
[0039] Figure 5 shows a schematic of the two modes of operation of the permanent magnet according to the polarisation of the lower tablet.
[0040] Figure 6 shows a detail of the support of the lower blades in which instead of making use of a second strip, use is made of a flange on the frame when the blades are vertical.
PREFERRED EMBODIMENT OF THE INVENTION.
[0041] The present invention consists of a mould frame for pressing tiles with magnetic securing of blades in which by means of the combined disposition of recesses for housing magnetic field generating assemblies, the securing of the blades is achieved.
[0042] Four preferred embodiments are described below in which configurative particularities are detailed according to the position of the blades and whether the magnetic field is created by an electromagnet or by an electro-permanent magnet.
First embodiment: Use of electromagnet and vertical disposition of the blades.
[0043] The first embodiment is shown in figure 1 wherein the plan and elevation are shown of the frame (1) together with a detail view of the cross section with the means of securing the blade (3).
[0044] In the plan two windows (1.4) are shown which allow two tiles to be configured, the window (1.4) on the right does not have blades (3) while that on the left does. The representation has been simplified in this view of the blades (3), the lines of the shoulder (3.1) not being shown in order to facilitate the understanding thereof.
[0045] The blade (3) assures its position by means of some securing strips (4, 5) which control the exact position of the blades (3) with respect to the frame (1).
[0046] Figure 6 shows a detail of this embodiment and another from the rear in which the possibility is also presented of doing without the lower strip (5) since it is the frame itself which includes a flange of the frame.
[0047] The securing action is achieved with an electromagnet configured by means of a coil (2) which is housed in a recess (1.3) in channel form from which emerges an inner projection (1.2) through which the magnetic field generated by the coil (2) is channelled.
[0048] The excitation of the coil (2) is what establishes the control over the force securing the blades (3) so, when this is not present, the interchange is possible.
[0049] The blades (3) can be divided into several pieces which cover the entirety of the interior perimeter of the window (1.4) or it can be a single piece covering it totally.
[0050] The frame (1) includes some perforations (1.1) by which its securing to the tile shaping mould is assured.
Second embodiment: Use of electromagnet and horizontal disposition of the blades.
[0051] This second embodiment is represented in figure 2 wherein the frame (1) likewise has two windows (1.4) only this time the blades (3) are located on the frame (1), on a shoulder (1.5) around the perimeter of each of the windows (1.4).
[0052] The means of coupling are the same, but by facing the blade (3), the projection (1.2) which is inside the recess (1.3) in which the coil (2) is housed, is now directed upwards.
[0053] In this situation the approximation to the blades (3) for their replacement is vertical, the rest of the elements being common to the previous embodiment.
[0054] It is worth pointing out that in this preferred embodiment use is not made of the securing strips (4, 5) which were present in the previous preferred embodiment.
[0055] Moreover the registering or adjustment function of the position of the blade is assured by the actual recess (1.5) of the frame (1) wherein the blade (3) is supported.
Third embodiment: Use of electro-permanent magnet and vertical disposition of the blades.
[0056] In this third embodiment shown in figure 3, just as in the first, the blades (3) are positioned vertically, between the registering strips (4, 5), relegating the magnetic securing means to a single recess (1.6).
[0057] Just as in the first preferred embodiment, the lower strip (5) can be replaced by a flange of the frame (1) such as is shown in the second detail of Figure 6.
[0058] In the recess (1.6) is located the core of the electro-permanent magnet (6) screwed to the bottom of the recess of the frame (1), flanked by some ferrite pieces (7) press-fitted between the core (6) and the internal wall of the recess (1.6) of the frame (1).
[0059] Between the core of the permanent magnet (6) and the bottom of the recess (1.6) is a tablet (8) which serves to control the magnetic flux of the electro-permanent magnet allowing control of the securing force to permit interchange of the blades (3).
[0060] In Figure 5 the circuit of the main magnetic flux established by the tablet (8) is shown schematically.
[0061] The tablet (8) is made of a magnetisable material, the material employed in this embodiment being preferably alnico, and it is surrounded by a coil (10).
[0062] The coil (10) acts during a short period of time depending on the size and nature of the material of the tablet (8) and it can be of the order of one second. In this time, the magnetic field that the coil (10) applies to the tablet (8) remagnetises it in the direction of interest.
[0064] When the excitation of the coil directs the poles of the tablet (8) with the N pole also toward the core (6), its flux crosses the core (6) and is prolonged until reaching the blade (3) applying the force necessary for the securing thereof.
[0065] The release of the blades is achieved by exciting the coil (10) again with a pulse which magnetises the tablet (8) with the position of its poles reversed, that is, with the S pole toward the core (6).
[0066] The magnetic flux created by the tablet (8), such as is shown in Figure (6) is conducted by the ferrites (7) since a magnetic circuit is established with the frame (1).
[0067] This magnetic circuit is closed before reaching the blades (3) whereby the latter are not reached by the magnetic field and they are free for replacement.
[0068] The internal configuration of the blades (3) proves identical to the first embodiment, wherein it is now only necessary to act on the means of magnetisation and demagnetisation when changing the blades (3), since the presence of the electro-permanent magnet (6) together with the ferrite pieces (7) assure a constant magnetic flux which guarantees the securing action without external excitation.
Fourth embodiment: use of electro-permanent magnet and horizontal disposition of the blades.
[0069] The changes are similar to those established between the first and the second preferred embodiment. As is shown in the fourth figure, the blade (3) is once again located in a recess (1.5) which performs the function of assuring its position.
[0070] Now the recess (1.6) is located pointing upwards so it is facing the larger surface of the blade (3).
[0071] Thus, the securing screw (9) is arranged vertically fixing the core of the permanent magnet (6) and the ferrite pieces (7); and both elements rest against the magnetisation and demagnetisation tablet (8) which occupies the space left in the bottom of the recess (1.6) of the frame (1).
[0072] Although in the first and third embodiments with reference to the means that make use of electromagnets, a single coil (2) is employed in each segment, the second and fourth embodiments use several sets of electro-permanent magnets (6) with their ferrite pieces (7) even covering the length of the blade (3).
1. Moulding frame for the pressing of tiles with magnetic securing of blades, characterised in that the frame (1) is constituted according to a mainly rectangular configuration, with
as many windows (1.4) as there are tiles, which has peripheral recesses (1.6, 1.3)
for housing the means of magnetically securing the blades (3) arranged peripherally
with internal shoulder (3.1), wherein these means of magnetically securing have means
of maintaining the securing magnetic field, as well as the means to eliminate the
magnetic field when interchanging the blades (3); and, this frame (1) likewise has
some perforations (1.1) intended to fix the frame (1) to the punching machine or mould.
2. Moulding frame for the pressing of tiles with magnetic securing of blades (3), according
to the first claim characterised in that the magnetic means of securing the blades (3) consist of an electromagnet constituted
by a coil (2) housed in a recess (1.3) in channel form the directrix of which defines
a closed circuit having an interior projection (1.2) which configures the securing
core.
3. Moulding frame for the pressing of tiles with magnetic securing of blades (3), according
to the second claim characterised in that the blades (3) are vertical and mounted on the internal face of the frame (3) where
the recess (1.3) in channel form is located which houses the coil (2) of the electromagnet,
the frame (1) having additionally some strips (4, 5) arranged above and below in recesses
in each corner of the window (1.4) for the registering of the correct position of
the blades (3) to be fastened magnetically.
4. Moulding frame for the pressing of tiles with magnetic securing of blades (3), according
to the third claim characterised in that the blades (3) combine for the registering of their position the use of upper strips
(4) and lower flanges (11) present on the frame (1).
5. Moulding frame for the pressing of tiles with magnetic securing of blades (3), according
to the second claim characterised in that the blades (3) are horizontal housed in an upper peripheral recess (1.5) of each
window (1.4) the channel (1.3) for housing the coil (2) being under the blade (3)
with the projection (1.2) on the interior of the channel (1.2) arranged upwards.
6. Moulding frame for the pressing of tiles with magnetic securing of blades (3), according
to the first claim characterised in that the magnetic means of securing the blades (3) consist of an electro-permanent magnet
constituted by a core (6) held by means of a screwed union (9) flanked by some ferrite
pieces (7) press-fitted between the core (6) and the internal wall of the recess (1.6)
all with the same pole directed toward the core (6), there remaining a space between
the magnetic assembly formed by the magnet core (6) plus the ferrite pieces (7) and
the bottom of the recess (1.6), wherein in this space there is a tablet (8) surrounded
by a magnetising coil (10) to establish the direction of the magnetisation in the
tablet (8) establishing two possible magnetic circuits, one which reaches the blade
(3) for the securing thereof and another that does not, to allow the interchange thereof.
7. Moulding frame for the pressing of tiles with magnetic securing of blades (3), according
to the sixth claim characterised in that the blades (3) are vertical and mounted on the internal face of the frame (1) where
the recess (1.6) is located for housing the permanent magnet (6), ferrite pieces (7)
and tablet (8) for control of the magnetisation, the frame (1) having additionally
of some strips (4, 5) arranged above and below in recesses in each corner of the window
(1.4) for registering the correct position of the blades (3) to be secured magnetically.
8. Moulding frame for the pressing of tiles with magnetic securing of blades (3), according
to the seventh claim characterised in that the blades (3) combine for registering their position the use of upper strips (4)
and lower flanges (11) present in the frame (1).
9. Moulding frame for the pressing of tiles with magnetic securing of blades (3), according
to the sixth claim characterised in that the blades (3) are horizontal housed in an upper peripheral recess (1.5) of each
window (1.4) the channel (1.6) for housing the magnetic assembly being under the blade
(3) directed upwards.