Plant for pressure casting sanitary articles

Abstract: A vertically movable lifting beam (3) is arranged above the moulds (6); for each mould (6) the beam (3) comprises an upper cylinder (7) to which the mould upper element (6d) can be connected, the mould lower elements (6a) being fixed on a lower plate (5) which can slide on a lower cross-member (2) in an axial direction; on the cross-member (2) between the lower plates (5) there are lateral element carriages (14) on which for each mould (6) locking rods (8) and the respective lateral elements (6b, 6c) of the adjacent moulds (6) are fixed; the rods (8) can be coupled to the upper frames (15) by coupling devices (9) and can be coupled at their lower end to the plates (5); the frames (15) are connected to the beam by weight compensation devices (24); tile mould group is positioned between two lateral cross-members (4) which can be moved in an axial direction on the lower cross-member (2) and be fixed to it, and on which the beam (3) engages during the clamping of the mould group; the plant can be equipped with a transverse locking device of which guides (20), carriages (17), cylinders (19) and transverse coupling devices (18) form part.

Description: The invention relates to a plant for pressure casting sanitary articles such as water closet pans and bidets with an open or closed rinsing rim, which uses moulds of synthetic material. The invention relates in particular to a pressure casting plant for sanitary articles with several moulds arranged one next to another, each provided at least with one mould lower element, two mould lateral elements, and at least one mould upper element and/or at least one mould transverse element, this or these being positioned transverse to the longitudinal direction of the moulds arranged in a row. Specifically, the moulds are arranged in a row with their mould lateral elements aligned, and which can be clamped in the alignment direction by two lateral cylinders, to hence form a mould group. A plant of this type is described in the document EP-B1-0 557 995. In the pressure casting plant described in that document, mould-carrier carriage pairs are provided together with a clamping device for joining the mould elements together by clamping them. The clamping device is positioned on a clamping frame separated from the mould-carrier carriage. The clamping frame can be raised and lowered between an operating position and a parking position. In a plant with at least 6 moulds, three respective pressure casting moulds are ready in the clamping frame to be put into operation. This means that three moulds are ready and clamped, and three products are cast. The clamping frame, which can be orientated upwards and downwards about a positionable axis relative to the mould element guide, is then orientated upwards and the moulds together with the moulded products are withdrawn by a lifting device and placed on the resting surface. In this case sixteen clamping devices are required for three moulds, and have to be slackened to withdraw the three formed products. When the first three forms have been removed from the clamping frame and placed on the resting surface, the clamping frame is returned to its operating position to enclose the next mould elements to be prepared and clamped, and to cast three formed products which are turned and laid on a resting surface after the sixteen clamping devices have been released. The document EP-0 569 855 describes a plant and process for pressure casting ceramic articles such as water closet bowls. This plant comprises a longitudinal guide following an axial direction, and several moulds which can be moved along said guide and are provided respectively with at least two lateral elements, a base element, and at least one transverse element which can be moved transversely to the axial direction between the lateral elements, plus an axial clamping device. The moulds are combined with a single clamping cage comprising transverse clamping devices to hold the mould lower element, the mould transverse element or elements and the lateral elements of each mould together. Suitable means join the mould transverse elements to the relative transverse clamping devices. The clamping cage is provided with one clamping frame for each mould, on which four transverse clamping devices are positioned, namely an upper, a rear, a lower and a front. The front device is fixed on a side which can be moved vertically on the relative clamping frame, and raised and lowered. The clamping frame can be positioned in a return position for withdrawing the formed product and also in a parking position transverse to the axial direction. When the mould elements have been moved apart, the formed product is withdrawn by an extraction device of known construction, which grips it. The two aforedescribed plants have a certain number of disadvantages. In the case of the plant of EP-0 569 855, each mould is located in a clamping frame within a single clamping cage. These devices are equipped for simple clamping and slackening of the individual moulds. Each clamping frame is provided with 4 transverse clamping devices which have to be slackened during the extraction of the formed products to enable them to be withdrawn by a special gripper. In the case of the plant described in EP-B1-0 557 995, the upper and mould lower element of the three moulds are respectively extracted, then the moulds with the formed products within them are rotated about a horizontal axis, and are laid on a parking surface. The lateral moulds are then slackened to hence release the formed products, the mould elements are again brought together, and are then re-rotated within the plant. Hence a number of different clamping devices located within the clamping frame and clamping cage have to be successively slackened and tightened during various processing stages for three moulds respectively. Document DE-C1-195 20 234, which is considered the closest prior art, discloses a plant for casting sanitary articles, of the above cited type, in which the core mould carriers comprise an equalizer having two connection points which move in the vertical plane of the plant frame. The equalizer has a central point about which a paired outer mould carriers are always kept at an equal distance. Coupling rods join the connection points of the equalizer to the adjacent outer mould carriers or to the fixed outer mould points. The two halves of the mould are removed at exactly the same time from a series of cast articles in order to avoid the damaging effects of differential uptake of water from one part of the mould remaining in contact with the cast longer than the other. An object of the invention is to provide a pressure casting plant for ceramic sanitary articles which is of simple construction and does not comprise complicated clamping devices. A further object is to provide a pressure casting plant which enables the time for the clamping and slackening stage to be reduced to a minimum. A further object is to provide a pressure casting plant which is perfectly compatible with the mechanical properties of moulds of synthetic material, which are characterised by a low elastic modulus and hence by substantial volume changes during plant clamping. These objects are attained according to the invention, as described in independent claims 1 and 3, by a plant of the initially described type in which: a) a vertically movable lifting beam is arranged above the moulds, b) for each mould the beam comprises an upper cylinder to which the mould upper element (if present) is connected, c) the mould lower elements of each mould are fixed on a lower plate slidable on the lower cross-member in the plant axial direction, d) on the cross-member in the plant axial direction, namely between the lower plates, there are movable lateral element carriages on which, for each mould, vertical locking rods and the respective lateral elements of the adjacent moulds are fixed, e) the locking rods can be coupled at their upper end by coupling devices which are connected to the lifting beam by weight compensation devices, and can be coupled at their lower end to the lower plates, f) the mould group is positioned between lateral cross-members which can be moved in an axial direction on the lower cross-member and be fixed to it, and on which the lifting beam engages during the clamping of the mould group, and finally g) the plant can be equipped with a locking device which is transverse both to the plant axis and to the direction of movement of the lifting beam. The mould group is composed of at least two moulds, and can be clamped against one side of a fixed cross-member which is rigid with the lower cross-member. The lateral cross-members are fixed by a vertically movable fixing device which can be moved hydraulically, pneumatically, electromechanically. electromagnetically or the like, and which during the plant clamping stage rests against a stop provided in the lower cross-member. The pressure casting plant is constructed such that on the lifting beam there rest the upper frames under which there are connected the upper cylinders, the rods of which are rigid with the upper plates, which are connected to the possible mould upper elements. The upper coupling devices into which the locking rods hook are provided in the upper frames. The pressure casting plant is constructed such that while the lifting beam is engaged on the lateral cross-members and on the fixed cross-member, the upper frames, the upper cylinders, the upper plates, the mould upper elements and the upper coupling devices with the locking rods can move freely in the plant axial direction. Below each lower plate there is a lateral element detachment device which is inactive when the mould group is clamped, and active against the carriages of the adjacent lateral elements when the moulds are slackened, so that these carriages become slightly detached from the lower plates. The moulds are hence slightly opened on slackening the plant, and the mould is separated from the cast products. The detachment device can be a pneumatically operated scissor device, which can urge the scissor sides against the carriages of the adjacent lateral elements. The operation of said scissor device can be synchronized with that of the lateral cylinders and with the fixing device for the lateral cross-members. To insert the possible inserts into the region of the rinsing rim, the moulds must be closed in the axial direction by moving the carriages of the lateral elements close to the lower plates clamped by the lateral cylinders. To prepare the pressure casting plant, those plant components situated on the lower cross-member, ie the lower plates, the carriages for the lateral elements and the lateral cross-members, are brought together by electrical movement. After this the lifting beam is lowered and engaged on the lateral cross-members, which are then fixed to the lower cross-member. This fixing can be snap-actuated hydraulically, pneumatically, electromechanically, electromagnetically or in another manner. The lateral cylinders are then pressurized to compress the thus formed mould group in an axial direction, until the locking rods on the lateral element carriage correspond in position with the upper coupling devices which rest on the lifting beam. In this position the coupling devices interact with the locking rods, and are coupled together for example by pins. The weight compensation devices are operated so as not to cause the weight of the upper frames with everything connected to chem, and of the lower plates with everything connected to them, to act on the mould lateral elements. Finally, the mould upper and lower elements are completely closed by pressurizing the upper cylinders. The mould lower elements resting on the lower plates are raised, by sliding rigid with the locking rods towards the lifting beam. At this point the mould is completely closed. The axial pressure is then increased by the lateral cylinders, until the moulds have been clamped with the necessary force also in an axial direction. The pressure rise in the upper cylinders and lateral cylinders can be correlated. Casting is effected at this point. When the automatic casting process has ended, the pressure in the upper and lateral cylinders is firstly decreased and the weight compensation device deactivated. The moulds are thus slackened, and the slide rods again slide downwards, until the lower element of the moulds again rests on the lower cross-member. Having accomplished this, the locking rods are released from the lifting beam, the lateral cross-members are released and finally the lifting beam transporting the upper elements of all the moulds is shifted vertically upwards. The individual moulds are then separated by removing the lower plates by the lateral element carriages by making them slide on the lower cross-member in the axial direction of the casting plant. This process is facilitated by the fact that during the slackening of the plant the lateral element detachment devices positioned below the lower plates are activated so that at the moment in which the moulds are removed, they are already detached from the formed products. During the slackening of the mould groups the lateral element detachment device lightly thrusts against the carriages of the adjacent lateral elements so that the moulds become opened. After the moulds have been opened, the formed products freely rest on the mould lower element and can be withdrawn by a traditional extraction device. After withdrawing all the formed products and axially returning the previously rinsed mould group, the possible inserts can be again inserted into the easily accessible open moulds. A possible mould transverse element can be brought up close by a transverse carriage, which can be coupled to the lateral element carriage, and the moulds can be clamped with the aid of a further clamping device. This mould transverse element is rigid with the rod of a transverse clamping cylinder. The mould transverse elements are brought into contact with the lateral elements before the lateral cylinders are put under pressure, and the transverse cylinders clamp them, in a direction transverse to the axial direction. The pressure increases in the transverse cylinders, lateral cylinders and upper cylinders can be mutually correlated. The advantages of this inventive solution are a simple plant construction without the need for a complicated locking and clamping device. For n moulds, the requirement is n upper cylinders, 4n locking rods,, two lateral cylinders and possibly n transverse cylinders. The time required for clamping and slackening the casting plant is considerably reduced as the locking is implemented automatically by compacting the moulds and lowering the lifting beam. It is sufficient simply to simultaneously tighten the two lateral cylinders, the upper cylinders and the possible transverse cylinders of each mould to hence obtain a high production rate ensuring a productivity increase over known plants. The simple construction and handling allow rapid mould closure and locking before the casting process, and rapid mould release and opening thereafter. In this manner all the advantages of a casting process associated with the use of moulds of synthetic material can be exploited. The merits and the constructional characteristics of the invention will be apparent from the ensuing description, illustrated by the accompanying drawings. Figure 1 is a front view of the casting plant according to the present invention. Figure 2 is a front view of the plant with the moulds compacted in the axial direction. Figure 3 is a front view of the plant with the moulds completely closed. Figure 4 is a view of the lateral element detachment device present below the lower plates. Figures 5A and 5B are side views of the open plant and clamped plant, showing the traditional clamping device. Figure 1 shows the casting plant of the invention in the open state. Variously connected to the frame (1) there can be seen, fixed to the base on which the plant components are arranged, a lower cross-member (2), a lifting beam (3), two lateral cross-members (4) and a fixed cross-member (12). The lifting beam (3) is supported by the frame (1) and can be moved vertically by a lifting device (10), which in this example is electrical and is positioned on the top of the frame, but could also be hydraulic and positioned on the fixed cross-member, or be of some other arrangement. In this constructional example, on the lifting beam (3) there are provided four upper cylinders (7) which carry the mould upper elements (6d) relative to four moulds, and sixteen upper coupling devices (9). In this embodiment the fixed cross-member (12) connected to the lower cross-member is at the centre of the casting plant and extends as far as the upper cross-member of the frame (1), but could also be in an off-centre position and be as tall as the lateral cross-members (4). On each side of the fixed cross-member (12) there are provided locking rods (8) with the relative lateral mould elements (6b) and (6c) of adjacent moulds. On the lower cross-member (2) there are provided four lower plates (5), which can be moved in an axial direction by carriages and are positioned respectively between two lateral element carriages (14), which are provided with locking rods (8) and on which the relative mould lateral element (6b, 6c) are connected, so that a lower plate (5) and a lateral element carriage (14) are alternately located one next to the other. The mould sequence (6) terminates at the two ends with two lateral element carriages provided with a single row of locking rods (8) and arranged to house a single mould lateral element (6b/6c), there being on the opposite side a lateral plate for redistributing the forces generated by the lateral cylinders (11) uniformly over the entire mould surface, during the clamping of the moulds (6). The terminal part consists respectively of two lateral cross-members (4) with axial clamping devices, the lateral cylinders (11) of which act on mould groups to clamp the moulds (6) one against another. The mould lower elements (6a) are located on the lower plates (5), the lateral elements (6b, 6c) of the moulds (6) being located on the lateral element carriages (14). The plant components positioned on the lower cross-member (2) can be drawn together by being slid along it to form a mould group. At the plant ends, the lateral cross-members (4) comprise a fixing device (13) resting on a locator (15) which projects below the lower cross-member (2) with which it makes intimate contact at the moment in which the plant is completely clamped. To arrange the casting plant, the plant components situated on the lower cross-member (2) are brought into contact (see Figure 2), after which the lifting beam (3) is lowered to engage in the lateral cross-members (4) and in the fixed cross-member (12). The lateral cross-members (4) are then fixed by the fixing device (13) which rests against the stop (16) below the lower cross-member (2). The lateral cylinders (11) are then pressurized to axially compress the mould group formed in this manner, until the lateral element carriages (14) with their locking rods (8) are below the coupling devices (9) which are rigid with the upper frames (15) connected to the lifting frame (3) by the weight compensation devices (24). In this position the coupling devices (9) interact with the locking rods (8), for example by the automatic insertion of a pin The weight compensation devices (24) are operated. The upper cylinders (7) are lowered until the upper element (6d) rests on the mould elements (6b, 6c). At this point, by means of the locking rods (8) and the reaction to the force of the upper cylinders (7), the lower plates rise to cause the mould lower elements (6a) to rest against the underside of the mould elements (6b, 6c). This position is shown in Figure 3. Finally the pressure in the upper cylinders (7) and in the lateral cylinders (11) is increased until the moulds (6) become clamped with the necessary force for the pressure casting. At this point the casting cycle can proceed. After the articles, in this case water closet bowls, have been automatically cast, the plant is opened by the reverse of the aforedescribed operations. The lateral cylinders (11) and upper cylinders (7) are slightly released, the upper cylinders (7) are completely opened, the pins of the upper coupling device (9) are automatically extracted, the lifting beam (3) is raised and the lateral cylinders (11) are completely opened. The formed products, ie the water closet bowls, are detached from the moulds (6b, 6c) with the lateral element detachment device (22) and can be withdrawn after the casting plant has been completely opened. The individual elements of the moulds (6) are rinsed and the plant is again recomposed in the axial direction and locked by the lifting beam (3), after which a new casting cycle can commence. Figure 4 is a view of the lower plate (5) from below. This shows a scissor-type lateral element detachment device (22), the drive device (21) of which is operated in accordance with the movement of the lateral cross-member (4). On opening the casting plant, the elements (22) of the scissor device are moved towards the plant axis so that the two adjacent lateral element carriages (14) can be easily moved in the direction of the plant axis in opposite senses. As the mould lateral elements (6b, 6c) are fixed to the lateral element carriages (14), these become detached from the formed products, which remain rigid with the lower plates (5). The mould elements (6a, 6b and 6c) are hence already separated at the moment in which the plant is completely open. Figures 5A and 5B show a side view of the casting plant when opened and closed. The device for clamping the casting plant transversely to the axial direction can be seen. The transverse carriages (17) travel along the transverse guide (20) towards the moulds (6) present in the mould group. The transverse cylinder (19) is rigid with the mould transverse element (23) which is coupled to the other mould elements by hooking the transverse carriages (17) to the lateral element carriages (14) by means of the transverse coupling devices (18). As in the case of the upper coupling devices (9), these transverse coupling devices (18) are free to move in a direction axial to the plant. These figures show the usual inclination for this type of plant, which is provided in order to easily discharge the casting material residues. The plant shown in Figure 5B is clamped in three directions. Given the simplification of the clamping devices, this type of plant allows a considerably higher productivity than previously illustrated plants. The casting plant according to the invention comprises less clamping devices than previously known plants, and a much smaller number of wearable parts. The individual characteristics of the invention can be widely modified without limiting its range of protection. The individual coupling devices can be implemented by pins, hooks, etc. The operation of the locking and/or coupling and/or fixing devices can be pneumatic, electromechanical, electromagnetic or other. Correlation between the operation of the lateral element detachment devices and the movement of the lateral cross-members or of the fixing and/or locking devices can be achieved by any suitable device. The lateral element detachment device can also be based on other principles, such as by pressurizing the cylinders situated below the lower plates at the moment of slackening the pressure casting plant, and causing them to thus urge the cylinder carriages. Mould opening could also be achieved by a varying pressure causing slight vibrations in order to more easily detach the formed products.

Claims: A pressure casting plant for sanitary articles, comprising at least two moulds (6) constructed of synthetic material and positioned adjacent to each other, each provided with at least one mould lower element (6a), two mould lateral elements (6b, 6c) and at least one mould upper element (6d), the moulds (6) being aligned, with their mould lateral elements (6b, 6c) side by side and clamped in an axial direction by two lateral cylinders (11), to hence form a mould group, comprising: a beam (3) arranged above the moulds (6), the beam (3) comprising, for each mould (6), an upper cylinder (7) to which the mould upper element (6d) is connected, wherein the mould lower elements (6a) of each mould are fixed on a lower plate (5) slidable on a lower cross-member (2) in an axial direction, characterised in that the beam (3) is a vertically movable lifting beam, on the lower cross-member (2) in the plant axial direction, namely between the lower plates (5), there are lateral element carriages (14) on which, for each mould (6), locking rods (8) and the respective lateral elements (6b, 6c) of the adjacent moulds (6) are fixed, the locking rods (8) are connectable at their upper end to upper frames (15) by upper coupling devices (9), and are connectable at their lower end to the lower plates (5), the upper frames (15) are connected to the lifting beam (3) by weight compensation devices (24), the mould group is positioned between two lateral cross-members (4) which are movable in an axial direction on the lower cross-member (2) and are fixable to it, and on which the lifting beam (3) engages during the clamping of the mould group, and the plant is equipped with a transverse locking device, of which guides (20), carriages (17), cylinders (19) and transverse coupling devices (18) form part. A pressure casting plant for sanitary articles according to claim 1 further comprising transverse element (23). A pressure casting plant for sanitary articles, comprising at least two moulds (6) constructed of synthetic material and positioned adjacent to each other, each provided with at least one mould lower element (6a), two mould lateral elements (6b, 6c) and at least one mould transverse element (23), the moulds (6) being aligned, with their mould lateral elements (6b, 6c) side by side and clamped in an axial direction by two lateral cylinders (11), to hence form a mould group, comprising: a beam (3) arranged above the moulds (6), wherein for each mould (6) the lifting beam (3) comprises an upper cylinder (7), the mould lower elements (6a) of each mould are fixed on a lower plate (5) slidable on a lower cross-member (2) in an axial direction, characterised in that the beam (3) is a vertically movable lifting beam, on the lower cross-member (2) in the plant axial direction, namely between the lower plates (5), there are lateral element carriages (14) on which, for each mould (6), locking rods (8) and the respective lateral elements (6b, 6c) of the adjacent moulds (6) are fixed, the locking rods (8) are connectable at their upper end to upper frames (15) by upper coupling devices (9), and are connectable at their lower end to the lower plates (5), the upper frames (15) are connected to the lifting beam (3) by weight compensation devices (24), the mould group is positioned between two lateral cross-members (4) which are movable in an axial direction on the lower cross-member (2) and are fixable to it, and on which the lifting beam (3) engages during the clamping of the mould group, and the plant is equipped with a transverse locking device, of which guides (20), carriages (17), cylinders (19) and transverse coupling devices (18) form part. A pressure casting plant as claimed in claims 1 to 3, characterised in that a mould group can be clamped against one side of a fixed cross-member (12) connected to the lower cross-member (2). A pressure casting plant as claimed in claims 1 to 4, characterised in that said lateral cross-members (4) are fixed by a fixing device (13) which rests on a stop (16), provided in the lower cross-member (2), at the moment of clamping the plant. A pressure casting plant as claimed in claim 5, characterised in that the fixing device (13) can be operated hydraulically, pneumatically, electromechanically, electromagnetically or the like. A pressure casting plant as claimed in claims 1 or 2, or in claims 4 to 6, when depending from claims 1 or 2, characterised in that , when in its closed position in which the upper cylinders (7) are locked, the lifting beam (3) is engaged in the lateral cross-members (4) and in the fixed cross-member (12), the lateral cross-members (4) are fixed to the lower cross-member (2), and the upper coupling devices (9) and the locking rods (8) are locked together, the upper frames (15), the upper cylinders (7), the mould upper elements (6d) and the upper coupling devices (9) with the locking rods (8) being able to freely move in the plant axial direction. A pressure casting plant as claimed in claims 1 to 7, characterised in that above the lifting beam (3) there is provided for each mould a weight compensation device (24) able to apply to said beam the weight of the locking rods (8), of the upper frame (15) and everything connected to it, and of the lower plate (5) and everything connected to it. A pressure casting plant as claimed in claims 1 or 2, or in claims 4 to 8, when depending from claims 1 or 2, characterised in that by means of the locking rods (8), when the upper cylinders (7) clamp the upper element (6d) of each mould by causing it to rest on the mould lateral elements (6b and 6c), the lower plates (5) rise by reaction to the force of the upper cylinders (7) to cause the mould lower elements (6a) to rest below the mould lateral elements (6b and 6c), to achieve the double purpose of not acting on the lower cross-member (2) with the thrust of the upper cylinders (7), and of not acting on the mould lateral elements (6b and 6c) symmetrically from above and below with the thrust of the upper cylinders (7). A pressure casting plant as claimed in claims 1 to 9, characterised in that below the lower plates (5) there is provided a lateral element detachment device (22), which is inactive at the moment of clamping the mould group, and active against the adjacent lateral element carriages (14) at the moment in which the moulds (6) are opened, so that these latter can be slightly detached from the lower plates (5) on which the mould lower element (6a) is positioned. A pressure casting plant as claimed in claim 10, characterised in that the lateral element detachment device (22) comprises a scissor device the elements of which are slackened during the clamping of the mould group, and urged towards the adjacent lateral element carriages (14) at the moment in which the moulds (6) are slackened. A pressure casting plant as claimed in claim 11, characterised in that the driver (21) of the lateral element detachment device is synchronized with the axial clamping device (11). A pressure casting plant as claimed in claim 11, characterised in that the driver (21) of the lateral element detachment device is synchronized with the fixing device for the lateral cross-members (13). A pressure casting plant as claimed in each of the claims 2 to 13, characterised in that to insert a mould transverse element (23) into the mould (6), each mould (6) can be clamped transversely to the axial direction, there being able to be brought close to each mould (6) a transverse carriage (17) able to be connected to the lateral element carriage (14) by means of the transverse coupling device (18), and to clamp the mould transverse element (23) by means of the transverse cylinder (19).

Inventors: CASSANI GIUSEPPE, WEGMANN REINHARD, CASSANI, GIUSEPPE, WEGMANN, REINHARD
Applicants: SACMI, SACMI COOPERATIVA MECCANICI IMOLA SOC. COOP. A R.L.
Application year: 1997
Main classification: B28B1
IPC codes: B28B7, B28B1, E03D11, B28B15