[0001] The invention relates to a device for manufacturing ceramic tiles, said device being
provided with a mould having a lower die and an upper die, with a filling cart for
introducing base material in said mould and with an endless conveyor belt, of which
at least one upper part, which extends at least substantially horizontally, is movable
in a direction towards and away from the mould, whilst at least two bunkers are disposed
one behind the other, when seen in the direction of movement of said upper part, so
as to deposit various materials on said upper part of the conveyor belt, via outlets
located near the bottom side of said bunkers, whereby said materials can be deposited
on base material present on the lower die by driving the conveyor belt during the
movement of the conveyor belt over said lower die.
[0002] Such a device is known from EP-A-0,300,523. In this known device a brush means is
arranged near the discharge end of the conveyor belt, so as to determine the layer
thickness of the material which is supplied from the bunkers on the horizontally extending
upper part of the conveyor belt. In practice this device is only suitable for processing
comparatively fine materials, whereby additional materials all have at least substantially
the same comparatively small grain size.
[0003] According to the invention a strickling means is disposed between the outlets of
the two bunkers, so as to determine the layer thickness of the material deposited
from one of said bunkers on the conveyor belt and conveyed under the outlet of the
other bunker in the direction of the mould, whilst the other bunker is provided with
a dosaging means for regularing the amount of material which is discharged from the
other bunker during each operation cycle.
[0004] When using the construction according to the invention it is possible to supply fine
material, whose layer thickness on the conveyor belt is determined by the strickling
means, from the one bunker, whilst a coarser granular material can be supplied from
the other bunker, which eventually results is a tile wherein the surface which will
be exposed to view will show relatively coarse grains besides the other fine material
forming the upper surface.
[0005] It is noted that from DE-A-1,170,850 there is known a device for manufacturing artificial
marble, said device being provided with two bunkers. During operation material flows
from said bunker on a conveyor belt for forming two layers of material on said belt,
one lying upon the other. The thickness of each layer is thereby determined by a strickling
board associated with the corresponding bunker.
[0006] The use of such strickling boards is only possible in forming relatively thick layers
of material. Contrary thereto the use of a dosaging means, as proposed by the present
invention, makes it possible to make only a very thin upper layer, covering eventually
the lowermost layer only in part.
[0007] Further in manufacturing tiles it is often required to be able to provide colour
and/or pattern gradations in the upper surface of the tile in a simple manner.
[0008] In view thereof the storage bunker could be provided with a plurality of compartments
arranged side by side in a row, said compartments being reciprocatingly movable at
least substantially in the longitudinal direction of said row.
[0009] When using such a construction materials having different colours and/or grain sizes
or the like may be introduced into the various compartments as required. By moving
the interconnected compartments to and fro during operation, when material is gradually
being discharged from the bunker, the material flowing from neighbouring compartments
will be mixed, so that when the device according to the invention is used the upper
surface of the tile that will be exposed to view can be given a patterned appearance.
[0010] The invention also relates to a method for providing striated patterns on the upper
surface of tiles which are formed in a mould, whereby a layer of base material is
provided on a lower die of the mould and whereby subsequently, additional material
deposited on said upper part is deposited on said layer of base material by means
of an at least substantially horizontally extending upper part of a conveyor belt,
whilst simultaneously the conveyor belt is driven, in such a manner that said additional
material falls from one end of the conveyor belt on the base material.
[0011] A similar method is likewise known from European patent no. 0,300,523.
[0012] The object of the invention is to create a possibility of forming wispy colour patterns
in the upper surface of the tiles.
[0013] According to the invention this can be achieved in that use is made of a conveyor
belt whose side receiving the material is provided with grooves disposed in a desired
arrangement, into which the additional material is introduced in order to be subsequently
deposited from said grooves onto the base material.
[0014] The grooves may or may not be provided in a random pattern on the side in question
of the conveyor belt, so that the material initially received in said grooves and
then deposited on the upper surface of the tile will land on the upper surface of
the tile in corresponding, whether or not random patterns.
[0015] Preferably also the cross-sectional dimensions of the grooves are varied, whether
or not in a randon manner.
[0016] A further influencing of the configuration may furthermore be effected by varying
the velocity of displacement of the belt.
[0017] In using the above mentioned method it is possible to form striated patterns on the
tiles by using only a relatively small quantity of the additional material.
[0018] For obtaining tiles having an appearance of artificial marble in the device according
the above cited DE-A-1,170,850 the layers of material lying upon each other are transported
by the conveyor belt towards a device comprising a number of interengaging fingers
upon which the materials are dumped for mixing the materials. So both said materials
have to be supplied in relative big quantities for obtaining the desired varied marble
pattern.
[0019] Further in EP-A-0 312 938 there is disclosed a device for manufacturing tiles having
a striped pattern. In said known device there is dumped on a conveyor belt a layer
of a base material and on said layer of base material there is dumped additional material
in various spaced strips. Then all the material lying on the conveyor belt is dumped
by the conveyor belt into a funnel. From said funnel the material is discharged into
moulds. Also is said known device there has to be dumped a relatively great quantity
of additional material on the base material for obtaining the stripe effect on the
surface of the tile due to the fact that a mixing of base material and additional
material will occur in the funnel.
[0020] The invention will be further explained hereafter with reference to the accompanying
Figures.
[0021] Figure 1 is a diagrammatic side elevational view of a device according to the invention.
[0022] Figure 2 is a diagrammatic elevational view of a part of a conveyor belt to be used
with the device of Figure 1.
[0023] Figure 3 is a diagrammatic, perspective view of a possible embodiment of a bunker
to be used with the device of Figure 1.
[0024] The device illustrated in Figure 1 comprises a diagrammatically depicted frame 1,
in which one or more lower dies 2 are reciprocatingly movable in vertical direction
by means of (a) setting cylinder(s) (not shown), as is indicated by means of the arrow
A. For each lower die 2 there is provided an upper die 3 co-operating therewith, said
upper die likewise being reciprocatingly movable in vertical direction with the aid
of setting means (not shown).
[0025] The device is furthermore provided with a bunker 4 for base material. A filling cart
5 is disposed under said bunker, which is reciprocatingly movable over the frame in
the direction according to the arrow B with the aid of drive means (not shown). The
filling cart has an opening 6 provided therein, into which opening, in the position
of the filling cart 5 illustrated in Figure 1, base material can flow from the bunker
4.
[0026] A further filling cart 7 is disposed more or less in the extension of the filling
cart 5, said further filling cart likewise being reciprocatingly movable in horizontal
direction. Near one of its ends the filling cart 7 has a passage 8, a sieve 9 being
disposed in the lower end of said passage. A charging slide 10 is reciprocatingly
movable in horizontal direction over said filling cart 7 with the aid of drive means
(not shown). The charging slide 10 is thereby provided with a receiving room 11 for
receiving additional material.
[0027] The filling cart 7 is mobile, together with a frame part (not shown), in which rollers
12 are rotatably journalled about a horizontal axis of rotation extending perpendicularly
to the direction of movement of the filling cart 7. Further rollers 13 - 16 extending
parallel to said roller 12 are journal led in a fixed frame part.
[0028] The rollers 12 - 16 function to guide an endless conveyor belt 17 in the manner illustrated
in Figure 1, said conveyor belt being guided by the rollers in such a manner that
the conveyor belt 17 has a horizontal part, which extends across the end of the filling
cart 7 directed towards the dies 2 and 3. The conveyor belt 17 is furthermore passed
over a roller 18, which is vertically movable.
[0029] Two bunkers 19 and 20 are arranged above the horizontally extending part of the conveyor
belt 17. Near its bottom end the bunker 20 is provided with an outlet opening, whilst
a roll feeder 21 is disposed near said outlet opening. In a similar manner the bunker
19 is near its bottom side provided with an outlet opening, whilst a roll feeder 22
is disposed near said outlet opening. A downwardly extending plate 23 functioning
as a strickling means is disposed between the two roll feeders, said plate with its
lower boundary edge at least substantially abutting against the upper side of the
upper horizontal part of the conveyor belt 17.
[0030] The bunker 20 is intended for accommodating fine additional material, whereas the
bunker 19 is intended for accommodating coarser additional material having a diameter
of 2 - 7 mm. In order to enable a well-dosaged discharge of said coarser material
from the bunker 19 the dosaging means 22 consists of a roller, whose circumferential
surface is is provided with fine recesses, said recesses being dimensioned such that
the recesses are suitable for receiving grains of the granular material present in
the bunker 19.
[0031] When the device is put into operation it will first be necessary to put the lower
die 2 in a position in which the distance between the upper side of said lower die
2 and the upper surface of the frame 1, across which the filling cart 5 moves to and
fro, will be at least substantially equal to the required thickness of the layer of
base material to be formed on the lower die 2. After the die 2 has been adjusted the
filling cart 5 will be moved towards the right, when seen in Figure 1, so that material
present in the recess 6 can be provided on the die 2 and also be smoothed by means
of the filling cart. Meanwhile the charging slide 10 has been placed in a position
in which the receiving room 11 provided in said charging slide 10 is filled with additional
material from a bunker (not shown). When the filling cart 5 moves towards the left,
when seen in Figure 1, after the layer of base material has been provided on the lower
die 2, said lower die is moved downwards over a distance corresponding with the thickness
of an upper layer yet to be provided, and the filling cart 7 is moved towards the
left, when seen in Figure 1, so that the sieve 9 will come to lie above the lower
die 2. The frame part supporting the roller 12 will thereby move along with the filling
cart 7, so that the various movable parts will reach the position illustrated in dotted
lines in Figure 1. During this movement the roller 12 is prevented from rotating and
the roller 18 will move upwards from the position illustrated in full lines in Figure
1 towards the position illustrated in dotted lines.
[0032] When the sieve 9 is positioned above the lower mould the charging slide 10 is moved
to and fro above the sieve, so that material accommodated in the charging slide 10
can fall from the receiving room 11, through the openings in the sieve, on the layer
of base material, whereby any undesirable coarse constituents will be retained by
the sieve 9.
[0033] Then the filling cart 7, the charging slide 10 which is movable over said filling
cart and the frame part supporting the roller 12 will be returned to the starting
position illustrated in Figure 1, whilst at the same time the conveyor belt 17 will
be driven in the direction indicated by the arrow C, so that the upper part of the
horizontally extending part of the conveyor belt will move towards the left, when
seen in Figure 1. During this return movement of said parts from the position illustrated
in dotted lines to the position illustrated in full lines the material supplied from
the bunkers 19 and 20 which is present on said upper part will then be spread over
the material already present on the lower die 2.
[0034] When the filling cart 7 and the frame part supporting the roller 12 move towards
the left, when seen in Figure 1, material is supplied from the bunkers 19 and 20,
whilst a surplus of fine material supplied from the bunker 20 is retained by the strickling
means 23.
[0035] Since it is not necessary for the granular materials supplied from the bunker 19
during the latter movement of the various movable parts to move past the strickling
means 23, said strickling means 23 can be arranged with its lower edge quite close
to the upper surface of the conveyor belt. The quantity of granular material which
can be supplied during each operating stroke of the device can be regulated by the
number of revolutions the dosaging means 22 is caused to make, since the quantity
per revolution of the dosaging means is at least substantially determined by the number
of recesses provided in the circumferential surface of the dosaging means for receiving
the granular material. Thus it is possible, with the aid of the dosaging means 22,
to influence the quantity of material deposited on the belt 17 during each operating
stroke.
[0036] After all the material has thus been deposited on the lower die 2 the material can
be compressed between the lower die 2 and the upper die 3 in the required manner.
After that the upper die 3 is moved upwards again and the lower die 2 is positioned
such that when the filling cart moves to the right, when seen in Figure 1, the tile
now formed will be moved to the right by said filling cart, so as to be discharged.
[0037] Preferably a strickling means 25 is mounted at the end of the filling cart 7, so
as to strickle material present on the upper surface of the frame 1. Said strickling
means 25 is thereby connected to the filling cart 7, by means of guide rods or the
like, in such a manner that said strickling means 25 can move, parallel to the direction
of movement of the filling cart 7 during operation, along a very limited distance,
with respect to the filling cart. As a result of this it is effected that when the
filling cart 7 moves towards the left, when seen in Figure 1, the filling cart 7 will
push the strickling means 25 ahead as far as the position of the strickling means
illustrated in dotted lines in Figure 1, in which position the strickling means is
supported on the left-hand side of the recess in the frame 1 supporting the lower
die 2. When subsequently the filling cart 7 and the roller 12 of the conveyor belt
17 connected thereto are moved towards the right, the strickling means 25 will initially
remain behind in the position illustrated in Figure 1, and not be carried along by
the filling cart 7 before the roller 12 has also been moved along a certain distance.
Consequently, when the various movable parts move towards the right, when seen in
Figure 1, the strickling means 25 will follow the roller 12 of the conveyor belt 17
and thus strike off any material which has fallen from the conveyor belt 17 on the
frame 1, near the end of the conveyor belt 17 located near the roller 12, so that
no more material will be present on the upper surface of the frame 1, which material
will prevent the effective closing of the die 3.
[0038] Preferably use will be made of a conveyor belt 17, whose upper surface coming into
contact with material supplied from the bunkers 19 and 20 is provided with grooves
26, as is diagrammatically depicted in Figure 2. Such grooves may be provided along
the entire length of the conveyor belt, whether or not in a random and erratic pattern,
whilst also the cross-sectional width of the grooves may extend in a varied, preferably
erratic manner along the length of the grooves. The adjustment of the device will
generally be such that the fine material from the bunker 20 fills the grooves, whilst
at least very little of said material is present on the part of the relevant surface
of the conveyor belt located between the grooves.
[0039] It will be apparent that the material accommodated in the grooves 26 will also be
deposited on the upper surface of the tile in wisps corresponding with the arrangement
of said grooves, so that wispy patterns will be provided in the tile that is eventually
manufactured. The configuration of said wispy patterns can furthermore be influenced
by varying the velocity of movement of the conveyor belt when the material is being
deposited on the upper surface of the tile by means of the conveyor belt.
[0040] Figure 3 shows an embodiment of a bunker 27, which may e.g. be used instead of a
bunker 19 or 20, or for the supply of material to the charging slide 10. Near its
bottom end this bunker is again provided with an outlet or dosaging means 28. In the
illustrated embodiment the bunker is built up of two parts 29 and 30 located one above
the other. The upper part 30 of the bunker is divided, by means of a number of division
plates 31, into a number of compartments arranged in a row. Materials having different
colours and/or grain sizes and the like may be deposited in the various compartments
arranged side by side. By moving said upper part 30 of the bunker to and fro (arrow
D) with the aid of drive means (not shown) during operation, the materials present
in the various compartments will be mixed in a random manner while flowing from the
upper part 30 of the bunker into the lower part 29, which will eventually result in
corresponding, random patterns of the additional material provided on the upper surface
of the tile.
[0041] It will be apparent that it is also possible to construct the bunker 27 in one piece,
whereby the bunker can be made to move reciprocatingly in its entirety during operation.
1. A device for manufacturing ceramic tiles, said device being provided with a mould
having a lower die and an upper die, with a filling cart for introducing starting
material in said mould and with an endless conveyor belt, of which at least one upper
part, which extends at least substantially horizontally, is movable in a direction
towards and away from the mould, whilst at least two bunkers are disposed one behind
the other, when seen in the direction of movement of said upper part, so as to deposit
various materials on said upper part of the conveyor belt, via outlets located near
the bottom side of said bunkers, whereby said materials can be deposited on base material
present on the lower die by driving the conveyor belt during the movement of the conveyor
belt over said lower die, characterized in that a strickling means is disposed between
the outlets of the two bunkers, so as to determine the layer thickness of the material
deposited from one of said bunkers on the conveyor belt and conveyed under the outlet
of the other bunker in the direction of the mould, whilst the other bunker is provided
with a dosaging means for regulating the amount of material which is discharged from
the other bunker during each operating cycle.
2. A device according to claim 1, characterized in that said dosaging means is a drum,
in whose circumferential surface recesses are provided for receiving grains of said
granular material.
3. A device according to claim 1 or 2, characterized in that a strickling means is provided
on the movable part of the conveyor belt, said strickling means cooperating with the
upper surface of a frame accommodating the lower die, whereby the strickling means
is connected to the movable part of the conveyor belt via a mechanism allowing a lost
movement, all this in such a manner that when the movable part moves over the lower
die in a first direction the strickling means is moved along with the movable end
of the conveyor belt, and that when the movable part moves in an opposite direction
the strickling means initially remains stationary and is not moved along before the
discharge end of the horizontally extending part of the conveyor belt has been moved
along a certain distance.
4. A device according to claim 2 or 3, characterized in that said strickling means is
connected to a charging lorry disposed under the horizontal part of the conveyor belt,
which is movable to and fro during operation.
5. A device according to any one of the preceding claims, characterized in that the surface
of the conveyor belt, on which material is deposited by means of the conveyor belt,
is provided with grooves.
6. A device according to claim 5, characterized in that said grooves are provided on
the surface in a random arrangement.
7. A device according to claim 5 or 6, characterized in that the cross-sectional dimensions
of the groove are varied along the length of said grooves.
8. A device according any of the preceeding claims, characterized in that a storage bunker
is provided with a plurality of compartments arranged side by side in a row, said
compartments being reciprocatingly movable at least substantially in the longitudinal
direction of said row.
9. A method for providing striated patterns on the upper surface of tiles which are formed
in a mould, whereby a layer of base material is provided on a lower die of the mould
and whereby subsequently, additional material deposited on said upper part is deposited
on said layer of base material by means of an at least substantially horizontally
extending upper part of a conveyor belt, whilst simultaneously the conveyor belt is
driven, in such a manner that said additional material falls from one end of the conveyor
belt on the base material, characterized in that use is made of a conveyor belt whose
side receiving the material is provided with grooves disposed in a desired arrangement,
into which the additional material is introduced in order to be subsequently deposited
from said grooves onto the base material.
10. A method according to claim 9, characterized in that the velocity of displacement
of the belt is varied.