GB2494109A

GB2494109A - Two part mould mountable on an endless conveyer

Info

Publication number: GB2494109A
Application number: GB201114510A
Authority: GB
Inventors: Meirion Gribble
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-08-23
Filing date: 2011-08-23
Publication date: 2013-03-06
Anticipated expiration: 2031-08-23
Also published as: GB2494109B; GB201114510D0

Abstract

Moulding apparatus has two mould parts 12, 14 which fit together to enclose a cavity or separate for access to the cavity. The moulds preferably move on a conveyor 22 between a zone in which they are charged with a substrate 37; a zone where the substrate cures to form a three dimensional solid; and a zone 50 where the mould opens for release of the finished article 54. The mould can open and close in response to a continuous looped guide (18, fig 1) whose distance varies from the conveyor 22 and engages an element (46, fig 1) on one of the parts of the mould; or by selective engagement of one or two toothed wheel(s) (106, fig 8) with tracks (107, fig 8) for rotation, the wheel(s) being rigidly attached to one of the mould parts via the hinge pin. There are ideally vibrating elements 56, 58. Nozzle 48 can be rotatably mounted to move with an aperture and/or non return valve on one of the mould parts during filling. The conveyor 22 can be a looped endless chain. The apparatus preferably operates in a housing to allow treatment and controlled venting of gases. The mould parts may include heating elements, ducts for heated fluids and/or cooling means.

Description

METHODS AND APPARATUS FOR MOULDING ARTICLES

The present invention relates to methods and apparatus for moulding articles.

According to a first aspect of the invention, there is provided moulding apparatus comprising mould means, the mould means comprising first and second mould elements which are mounted for movement between a closed position in which together they provide the surfaces of a closed moulding cavity contained between the elements, and an open position, the apparatus further comprising conveyor means for conveying the mould means through operating zones in which the moulding cavity is charged with a moulding compound, the moulding compound is processed to convert the moulding compound into a three dimensional article and the mould elements are caused to move to their open position to enable removal of the three dimensional article, the apparatus further comprising means for controlling relative movement of the first and second elements between the open and closed positions as the mould means is conveyed by the conveyor means.

In a preferred embodiment, the conveyor means comprises an endless chain arranged to haul the mould means around the apparatus from one operating zone to another. In the preferred apparatus, the endless chain is driven at a constant speed although it is envisaged that the endless chain can be driven at variable speeds to allow for the moulding compound to be processed under the most appropriate conditions for that compound.

Preferably, the means for controlling relative movement of the first and second elements between the open and closed positions as the mould means is conveyed by the conveyor means comprises guide means that is arranged to define the locus of movement of a portion of the second mould element as the mould means is conveyed by the conveyor means. Preferably, the guide means comprises a continuous looped guide channel mounted parallel to a portion of the conveyor means! but which diverges therefrom at one or more locations to an extent to enable the mould elements to occupy their open position. If desired, the guide means may comprise supplementary chain means to assist movement of the second mould element, which chain may be driven if desired. In preferred apparatus according to the invention the mould elements occupy their open position to enable insertion of moulding material to the moulding cavity.

In an alternative embodiment, the means for controlling relative movement of the first and second elements between the open and closed positions as the mould means is conveyed by the conveyor means comprises hinge means which couples the first and second mould element together to permit the second mould element to move relative to the first mould element to open and close the mould means.

Preferably, one end of the hinge means comprises a wheel rigidly secured thereto, for engaging with track means as the mould means is conveyed by the conveyor means.

Preferably, the hinge means is rigidly secured to one of the mould elements and rotatably secured to the other mould element.

The track means preferably comprises two track elements vertically displaced with respect to each other.

Preferably, the wheel engages with one track element on the under side of the wheel, and the other track element on the upper side of the wheel The track elements are preferably separated along the length of the conveyor such that the wheel engages with only one track element at a given time to open and close the mould means.

Alternatively, the hinge means comprises a wheel rigidly secured at either side thereof for separately engaging with a track element arranged either side of the mould means. Preferably, the track element arranged at the one side of the mould means is vertically displaced with respect to the track element arranged at the other side of the mould means and the track elements are separated along the length of the conveyor such that only one wheel engages with a track element at a given time.

Preferably, the wheel arranged at the one side of the hinge means engages with the track element arranged on the one side, on the bottom of the wheel and the wheel arranged at the other side of the hinge means engages with the track element arranged on said other side, on the top of the wheel, to open and close the mould means.

In preferred apparatus according to the invention the mould means preferably comprises a plurality of mould assemblies each comprising said mould elements.

The preferred apparatus hereinafter described employs a horizontally disposed conveyor means, however this configuration may be varied in order to increase productivity of the apparatus. In the case where a very large number of mould assemblies is required on the conveyor means, for example up to 60 mould assemblies, this may lead to an undesirable length of apparatus. In order to accommodate different numbers of mould assemblies, the apparatus may be of modular construction so as to enable the apparatus to be re-configured to designs whereby the conveyor has a short linear, long linear or convoluted path -convoluted vertically and/or horizontally and hence one may provide the required length of conveyor means but in a shorter distance. Such an arrangement has commercial advantages in that less space is needed to accommodate the apparatus, which can contribute to a decrease in the costs associated with running the apparatus. It is also possible to design and operate the apparatus in a vertical plane where height of the factory is more readily available than floor space, for example in a circular fashion such as on a carousel.

It is preferred that the apparatus includes a mould filling station for pumping moulding compound into closed moulding cavities. It is preferred that the moulding compound is provided by feeding means which carries moulding compound to be fed to the moulding cavity. It is envisaged that pipes from the mould filling station align with apertures in the mould elements carried by the conveyor means and inject moulding compound into said cavities. Preferably, the moulding compound is injection moulded into the cavity. The process preferably involves cold filling of the moulding cavities.

It is also envisaged that there are vents within the mould elements for degassing moulding material that has been injected into the mould cavity, to reduce the build up of vapours that are associated with the moulding compound.

It is envisaged that the conveyor comprising the endless chain is coiled as a series of adjacent loops. The loops may have the same diameter or may be of varying diameters. The looped configuration may be contained within a housing that is preferably insulated, thereby retaining heat in the surroundings of the mould assemblies. Such a structure allows for an increased efficiency in operating the apparatus because by retaining heat within the apparatus there is a reduction in the amount of heat needed to age or activate moulding compound contained within the mould means.

Preferably, the housing for the looped endless chain region includes venting means for the removal of vapour or gaseous material that is released from the mould assemblies during aging or curing of the moulding compound.

In a preferred arrangement, the venting means includes filters or gas scrubbers to remove impurities from waste gases before being released to the atmosphere. It is also possible that vented air can be re-circulated into the housing to moderate temperatures within the housing to provide optimum conditions for treating the moulding compounds that are being processed.

Preferred apparatus according to the invention comprises means for applying vibration to the mould means. Preferably, the means for applying vibration is arranged to vibrate the mould assemblies when the mould elements are moved from their closed position to their open position. Vibrator means of preferred apparatus according to the invention is also arranged to vibrate moulding compound introduced into the cavity. The frequency and amplitude of the vibration applied to the mould means is selected in accordance with the configuration of the mould cavity and the moulding compound employed, so as to assist desired filling of the mould, compacting of the moulding compound in the mould cavity and/or emptying the mould means. The vibrator means may comprise conventional rotary units which can provide a range of vibratory forces and combined if necessary to increase the power and direct the effective vibrational force. In one preferred apparatus, each mould assembly is equipped with its own set of vibrators mounted to vibrate one or more of the mould elements.

In a preferred arrangement, there is a plurality of vibrators that act on the mould elements. Preferably, there is a single vibrator associated with the first mould element that is secured to the endless chain conveyor. This arrangement allows for a more even distribution of vibrational forces across the mould cavity, so allowing for a more even flow and settling of the moulding compound within the mould cavity.

Preferably, there are also two vibrators associated with the second mould element and this assists the action of the larger vibrating element that acts on the first mould element secured to the endless chain.

It is envisaged that there are two regions of the apparatus at which vibrators are mounted to apply vibrations to the mould assemblies. There may be a series of vibrator units located at the closing position for the mould assemblies and another series ot units at which the mould assemblies move into the open position. This can assist in the release of articles from the mould assemblies.

The vibrator units located at the closing position preferably transmit the forces through a series of rollers which are mounted on an arm which is preferably a "floating arm" that can assist in absorbing unusually large fluctuations in vibrations that may occur. In either case, the amplitude and frequency of vibrations may be determined by trials on specific tooling! point of engagement, duration etc. and is preferably controlled by means of limit switches and speed regulators.

In a preferred arrangement the first and second mould elements are connected to springs which are attached to the arm that supports the rollers. Preferably, the springs connect with either end of the mould element that is supported by the endless chain. The springs may include a flange on which the ends of the mould element sit. Alternatively, the mould element may comprise flange elements to which the ends of the springs can be secured to provide a more permanent connection.

It is preferred that the springs are secured to the mould elements by way of a releasable attachment to enable mould elements to be interchanged when a different type of moulded component is required.

The invention provides in another of its aspects a mould assembly comprising first and second mould elements which are connected together by hinge means and which are arranged to occupy a closed position in which together they provide the surfaces of a closed moulding cavity contained between the mould elements, and an open position for providing access to the cavity, the mould means further comprising means tor cooperating with conveyor means to permit the mould assembly to be conveyed by the conveyor means and means for opening and closing the moulding cavity as permitted by the hinge means, as the mould means is conveyed by the conveyor means.

Preferably, the mould assembly comprises means for vibrating at least one of the first and second mould elements.

A mould assembly according to the invention preferably further comprises means for heating the first and second mould element, for example by means of electricity.

Preferably, the means for heating the first and second mould element comprises a heating element embedded in the first and second mould elements and in a preferred arrangement the means for heating extends along the length of the mould element.

The supply of power to the element is preferably by way of a fully self-contained unit that is sealed to avoid the ingress of liquid or gaseous material released during processing of the moulding compound. The sealed unit contributes to the reliability of the device by avoiding damage to the power supply. Furthermore, having a sealed unit that can locate with connectors to the or each element, allows for the replacement of units.

Other forms of heating may be used, for example, the mould elements may comprise ducts though which heated liquids such as oil or water are circulated. The heated oil or water may be pumped through the mould element at a suitable temperature for processing the moulding compound. In addition, there may be channels which can also be used to circulate a fluid to cool the mould elements after processing. Cooling can also contribute to curing of the moulding compound contained within the cavity formed by the mould elements. It is preferred that the mould elements comprise apertures by which a material can be injection moulded into the cavity formed by the mould elements. Preferably, the apertures include a valve, such as a non-return valve.

It is envisaged that the mould assembly further comprises sensor means to detect the relative position and condition of mould elements. The sensing means preferably comprises an infra-red sensor for determining the proximity of adjacent mould elements and/or to determine whether they have closed properly. If irregularities in the spacing between the elements are detected, for example if the mould elements have not closed properly, then an alarm can be actuated to warn an operator to check the apparatus before continuing. In addition to light sensors such as infra-red or UV sensors, there may also be thermo-sensors to detect the condition of the mould elements.

The infra-red sensor can preferably determine the heat given off by the mould assembly and can also be used to determine whether the moulding compound is at an appropriate temperature at a given stage in the process. Preferably, the sensor is arranged in communication with a controller that can be operated to stop the conveyor means or to alert an operator if a particular mould means does not conform to or falls outside defined parameters for that mould means at a given location during processing.

According to a further aspect of the invention, there is provided mould means the mould means comprising mould elements, the mould elements comprising heating elements that may extend partway along the mould elements or which may extend the wide length of the elements.

First and second mould elements are provided by a basic male and female punch and die. A floating hinge mechanism is provided at the edges of the mould elements, to allow the second mould element to arc towards the first mould element initially before tilting to become more parallel to it just before final closing. The first and second mould elements of this preferred mould assembly are designed for the production of roofing slate or tile and have two undercuts in opposing directions. In conventional compression moulding, this would require elaborate tool design incorporating sliding cores and ejectors to form the shape and remove the product from the tool. As the mould elements move to their closed position, the floating hinge causes the mould elements to pull more laterally to engage the undercut before final closing. On opening, the reverse is the case, the second mould element being pushed forwarded to clear one undercut while, at the same time, helping to push the product away from the second undercut. The product is then able to fall away freely from the elements.

In general, the moulding tools required for use in apparatus according to the present invention in which vibrator means are employed, and that are associated with the mould means, do not need to be of the high grade steel that is normally associated with compression or injection moulding. Materials such as case aluminium or kirksite may be used, but each mould element is preferably designed and constructed of material appropriate to the products to be produced.

Apparatus and methods according to the invention enable moulding of articles having undercuts in their surfaces and/or with good surface finish in high quantities using simple apparatus and low cost mould components. The preferred apparatus hereinafter described is especially suitable for use with moulding materials which can be conveniently placed in a mould in open condition. It is particularly suitable for moulding articles from thermosetting compositions such as phenolic moulding compounds, thermosetting rubber compounds or polyester compounds known for use in dough moulding and sheet moulding. In particular, the apparatus can be used with granulated materials used to make roofing slates, for example granulated slate.

The apparatus allows for the granules to flow relative to one another as a result of the vibrations transmitted to the mould elements. This results in a more even dispersion of the granules within a binder such as a resin and therefore an improved composite product.

It is to be understood that the invention is to cover combinations of the aspects of the invention as described. In order that the invention may become more clear there now follows a description to be read with the accompanying drawings, of one example of apparatus and method for moulding articles according to the invention, selected that has been to describe the invention by way of example only.

In the drawings: Figure 1 is a side view of the apparatus of the present invention with some parts broken away; Figure 2 is a side view of the apparatus of the present invention showing movement of the first and second mould elements as they are moved by the continuous chain; Figure 3 is a side view of the apparatus, of the present invention illustrating the filling of the mould by pumping moulding material into mould cavities; Figure 4 is a perspective view of apparatus illustrating a series of adjacent loops; Figure 5 is a sectional view through closed mould elements and vibrators of the mould assembly; Figure 6a is a side view of a mould assembly suitable for use in the apparatus of the present invention! having a moulding cavity for production of a flat tile having two undercuts in opposite directions; Figure 6b is a view of the mould assembly of figure 6a taken in the direction of arrow A in figure 6a; Figure 7 is an exploded view of the mould assembly and hinge of an alternative embodiment of the present invention; and! Figure 8 is a rear view of the mould means of figure 7 illustrating the engagement of the wheels with the respective track elements.

The illustrative apparatus is especially suitable for use with moulding materials which can be conveniently placed in a mould arranged in open condition. Referring to Figure 1 of the drawings, the apparatus comprises mould means formed a plurality of mould assemblies (10) (only two of which are shown in Figure 1) each comprising first (12) and second (14) mould elements which are hingedly connected together.

The apparatus further comprises conveyor means (16) for moving the mould assemblies (10) through operating zones A through 0 of the apparatus and guide means (18) for controlling orientation of the first and second elements (12, 14) with respect to each other as each mould assembly (10) is moved by the conveyor means (16).

The conveyor means (16) comprises two pairs of parallel channels (20) spaced apart at each side of the apparatus (only pair of channels (20) is shown in figure 1). Each pair of channels (20) are mounted in the vertical plane and the spacing between the pairs of channels (20) is sufficient to accommodate the mould assemblies (10). The channels (20) comprise an endless chain (22) running on sprockets (24, 26). The chains are driven at constant speed in tandem from an electric motor (30), in a clockwise direction as viewed in Figure 1. The channels (20) are mounted on stanchions (32), those at one side of the apparatus being adjustably secured to those at the other side of the apparatus so that the spacing between the sides of the apparatus may be adjusted in order to accommodate mould assemblies (10) of various widths.

The guide means (18) comprises two parallel looped guide channels (34) spaced apart one at each side of the apparatus (only one of which is shown in Figure 1).

The channels (34) are mounted in a vertical plane that extends parallel to the plane in which the channels (20) reside and are secured to the same stanchions (32). The spacing between the channels (34) is adjustable to match the spacing between the channels (20) and the channels (34) are arranged to extend parallel to the channels (20) for a portion of the length of the channels (20) at zones 0 and F. Approaching the left hand side of the apparatus as viewed in Figure 1 and in the direction of travel of the chains (22), the guide channels (34) progressively diverge from the channels (20) though zone G to an extent commensurate with the length of the second element (14) of the mould assemblies (10). The channels (34) run generally parallel to the chain (22) around the sprocket (26) through zone A and then progressively converge towards the channels (20) through zones B and C until they again run parallel therewith in zone D. Towards the right hand end of the apparatus as viewed in Figure 1 in the direction of the motion of the chain (22), the channels (34) diverge slightly from the chain (22), run parallel therewith around the sprocket (24) through zone E and then converge to again run parallel with the channels (20) to zone F. If desired, one or both of the channels (34) may contain an endless chain (not shown) and if desired these may be linked together by roller bearings similar to the rollers (28). The guide channels (34) define the locus of movement of a portion of the second element (14) of each mould assembly (10) as the mould means is moved by the conveyor means (16). It is important that the channels (34) are securely positioned in relation to the channels (20) in order to ensure accurate relative positioning of first and second elements (12,14) as the mould assembly (10) passes through the various operating zones.

Referring to figure 2, each mould assembly (10) is provided with electric heating elements (36) to enable moulding compound (37) in the mould cavity to be heated.

Electricity is supplied to the heating elements (36) and to vibrator units (38, 40, 42) of each mould element (12, 14) by way of a busbar (not shown) which is a continuous loop located adjacent to and parallel with the channel (20), and which is contacted by a shoe (not shown) attached to the first mould element (12). A thermocouple (not shown) is embedded in each of the mould elements (12, 14) and their output is fed to an electronic relay switch mechanism (not shown). To each shoe is attached a small electrical control box (not shown) housing controls. The box comprises an LED display (not shown) which indicates the operating temperature of each mould element (12,14), and an adjustable control by which the temperature can be set, usually around 120°C, for switching the heaters (36, 38) on and off as required.

The first and second elements (12, 14) of each mould assembly (10) are connected together at pivot (44) and may be moved about the pivot relative to each other between a closed position (as shown at the right hand side of Figure 1) in which together they provide the surfaces of a closed moulding cavity contained between the mould elements, and an open position (such as shown at the left hand side of Figure 1) permitting access to the moulding cavity. The first mould element (12) is provided with means (not shown) whereby it may be secured to the chain (22). The second element (14) is provided with means in the form of cam follower (46) which can roll captive in the channels (34). As the first mould element (12) is moved by the chain (22) of the conveyor means, the cam (46) follows the locus defined by the channels (34) and thus co-operates with the channels (34) to control movement of the second mould element (14) about the pivot (44), towards or away from the first mould element (12) to close and open the mould assembly (10), respectively.

Referring to figure 1 of the drawings, in use the apparatus is caused to complete an operating cycle by operating the motor (30) to cause the sprocket (24) to drive the chain (22) clockwise as viewed in Figure 1. This causes the first mould element (12) to be drawn through the apparatus, carrying with it the second mould element (14), which in turn moves about the pivot (44) under control of the channels (34). As each mould assembly (10) of the mould means is drawn through the apparatus it passes through operating zones A, B, C, D, E, F and G. In zone A, the mould elements (12, 14) are in their open position and a weighed charge of moulding compound (37) is placed into the moulding cavity exposed in the first element (12). In zones B and C, the vibrator units (not shown) are actuated to assist moulding compound (37) to flow and disperse evenly within in the mould cavity.

As viewed in Figure 1, the vibrations are applied vertically to the mould assembly as it moves into the closed position and travels horizontally in the apparatus. In zone D the first and second elements (12, 14) have fully assumed the closed position and the maximum moulding force is exerted on the elements (12, 14). Through zone E to zone F the mould means (10) is held in closed position whilst the mould assembly (10) continues to be heated and thus the moulding compound (37) in the cavity is aged under conditions of temperature and pressure to cure the moulding compound into a three dimensional article (54). In zone F, the cam (46) of the second element (14) is urged by the channels (34) to commence movement of the second mould element (14) about pivot (44) towards the open position. A short burst of vibration is applied by the vibrator units (not shown) to the mould means to assist this opening movement and to assist in releasing the moulded article (54) from the mould cavity.

In zone C as the mould elements (12, 14) pivot towards the open position, the article (54) is enabled to fall from the mould cavity. The mould assembly continues until it reaches zone A where the mould charging step is carried out to commence another cycle of operations.

The movement of the mould elements (12,14), as they pass through a complete cycle, is shown in Figure 3 with mould compound (37) being fed to mould elements (12, 14) in the open position via a feed outlet (48). Sensors (49), for example infra red sensors (as shown in figure 2), determine when the desired quantity of moulding compound (37) has been delivered to the moulding cavity and the relative orientation of the mould elements (12, 14). The mould compound (37) is cured/treated as it is moved along the conveyor and the final product (54) is released at point (50) onto a collection conveyor (52) which removes the final products (54) for cooling or further treatment or onwards to a packaging line. The collection conveyor (52) may include cushioning means (not shown) to absorb forces when a product (54) is released from the apparatus.

There is a sensor (55) which may be associated with the conveyor means (16) (as shown in figure 2) or the collection conveyor (52) so that the speeds of both are substantially matched to avoid an accumulation of final articles (54) on the collection conveyor (52). Vibrators are provided at locations (56) and (58) along the length of the conveyor (22). When the moulding compound (37) is fed to mould assembly (10), vibration occurs at location (56) where the mould element (14) is above element (12) to enable the compound to flow and be more easily distributed in the mould cavity. Vibrations are also applied as the element (14) closes down onto the element (12). Treatment/curing occurs as the mould assembly (10) passes along a loop until it reaches position (58) of the apparatus.

In the arrangement shown, the conveyor (22) is a U-shaped structure and at position (58), the conveyor (22) and associated vibrators are positioned above the assemblies (10). As the element (12) is now above element (14), the vibration causes the movable mould element (14) to drop away from mould element (12) with the assistance of gravity and the vibration also assists in loosening the moulded product (54) from the mould elements (12, 14) so that it can be deposited on collection conveyor (52).

As shown in Figure 4, the apparatus comprises a feed mechanism such as a mould filling station (60). The station (60) includes an internal cavity filled with moulding compound and pipes (62) which can contact with mould assemblies as they pass along the conveyor (22). The pipes (62) include non-return valves (not shown) to prevent back flow of injected material and also leakage of moulding compound (37) from the mould filling station (60). The mould filling station (60) is formed of a central cavity for holding moulding compound (37), and pipes (62) extend radially from the central cavity. The mould filing station (60) rotates about an axis that extends along the centre of the cavity, at a rate matching that of the movement of the conveyor (22).

The pipes (62) align with mould elements (12) that are carried by the conveyor (22).

The compound (37) may be injected into the mould cavities while cold, although material that has been heated can also be injected if the condition that is needed to process the moulding compound requires heating, for example to activate the compound.

The non-return valves (not shown) may also include a sensor (not shown) to detect when the required amount of material has been injected and then a controller (not shown) can prevent further flow of moulding compound to the mould cavity, thereby providing a more efficient mode of operation.

In the region of the conveyor (22) where the mould filling station (60) is situated, there is provided a vibrating element (64) which, by vibrating the mould elements (12, 14), assists in dispersing the moulding compound (37) within the cavity. The vibrating elements (64) are on the side of the moulding assembly where the moveable mould elements (14) are situated. This provides an arrangement where initially there is vibration of the moulding element (14), then vibration of the moulding element (12) occurs as the assemblies (10) pass through zones (56, 58) and the cycle is repeated when the mould assemblies (10) reach the point at which they are filled.

It is envisaged that the mould cavities of the assemblies (10) can be filled at least partially by the mould filling station (60) and then the mould element (14) can be allowed to open to permit more material to be introduced by a downstream nozzle (48). This opening of the mould element (14) also allows for another material to be introduced into the mould cavity such as a reactant, or a curing compound, so that the moulding compound (37) is caused to be activated to produce the final product.

Figure 5 shows a similar type of apparatus to that of Figure 3 except that the conveyor means (22) is caused to travel along a series of adjacent loops (66). By having a series of loops this allows for an increase in conveyor capacity in a reduced space. The loops (66) may be contained within a housing (not shown) which can be used to retain heat in the vicinity of that particular part of the conveyor. The housing may also include a control to adjust the amount of heat retained, or to allow for the introduction of air so that the temperature in the housing can be adjusted to suit the moulded compound (37) that is being used.

Figure 2 shows a detailed view of mould elements (12, 14) in association with vibrating elements (38, 40, 42). There is a large single vibrating element (38) associated with the mould element (12) that is attached to the conveyor (22). For the upper moveable mould element (14) there are two smaller vibrating elements (40, 42). Although two vibrating elements are shown, there may be more than two elements or even just one element. If there is a number of vibrating elements, then contact means are provided for independent operation of each vibrational element so that if there is an article to be moulded of an irregular profile, more vibrations can be applied to specific parts of the mould cavity to increase the flow of moulding compound (37) within the mould assemblies (10).

The vibrating elements (38, 40, 42) are secured to arms (68) that are supporting rollers (70a, 70b), which are in contact with mould elements (12, 14). The vibrating elements (38, 40, 42) contact the arms (68) by way of connectors (72). In the case of the arm (68) supporting upper rollers (70a) there is a damping mechanism such as a spring (74) which allows for controlled transmission of vibrations to rollers (70) and ultimately to the mould element (14).

In the case of mould element (12) the ends of the element (12) rest on spring member (76) which are supported on a support arm (78) that supports the arm (68) for the lower set of rollers (70b). It is envisaged that the element (12) sits on the spring (76) or alternatively, the element (12) may have a flange (not shown) secured to the spring.

Also shown is a sealed power pack (80) for supplying power to the mould heating elements (36), and the vibrating elements (38, 40, 42) via connections (82).

Alternatively, the vibrating elements (38, 40, 42) are powered by a separate power source (not shown).

The mould assembly shown in Figure 6 is suitable for use in the apparatus illustrated in figure 1 and comprises a basic male (12) and female (14) punch and die tools which provide first and second mould elements (12, 14), respectively. When in closed position, the male tool (12) and the female tool (14) define a moulding cavity for production of a flat tile (54) having depending edge portions (not shown) a depending lip portion (84) in the form of a re-entrant hook extending across the tile, a depending lip portion (86) extending across the tile and an upstanding hook portion (88). The lip portion (84) and the hook portion (88) define two undercuts extending in opposite directions. The male tool (12) is of cast aluminium and is formed with a reduced section (90). Steel hinge cradles (not shown) are secured to the reduced section (90) at either side of the assembly (10) and extend normal to it. Each hinge cradle is formed with an elongate slot (92) and provided with a cam follower (94).

Cam plates (96) at either side of the assembly (10) receive cam followers (98) in an arcuate slot (100). Each cam plate (96) is mounted on an axle (not shown) in an axle block (102) secured to the female tool (14). This construction provides a floating hinge mechanism at the edge of the mould assembly (10) where the moveable male tool (12) is provided with means (not shown) for securing it to the chain (22) of the conveyor means (16) and the female tool (14) is provided with a cam follower (104) at the extremity remote from the axle (not shown) for engagement with the guide means(18).

The purpose of the floating hinge is to allow the female tool (14) to become more horizontal just before final closing on the male tool (12) and before tilting about the hinge. Upon moving the female tool (14) from the open position to the closed position, the cam follower (104) constrained by the guide means (18), urges the female mould tool (14) to turn in an arc about the axle (not shown), but before final closing, it is pulled more laterally to engage the lip (84) and its undercut. The hinge may also include a biasing member (not shown) such as a spring that biases the female tool (14) to the male tool (12) during closing to ensure that they contact each other securely. On opening the mould means, the reverse is the case, whereby the female tool (14) is pushed forward away from the hinge to clear one undercut while at the same time, helping to push the tile (54) away from the second undercut. The tile (54) is then able to fall away freely from the opened mould. This assists in the prevention of the jarring of materials within the mould cavity and possible damage to the final product.

In accordance with a second embodiment of the present invention, as shown in figures 7 and 8, the mould assemblies (10) are opened and closed via a pair of wheels (106a, 106b) mounted to the pivot (40), which couples the mould elements (12, 14) together in a pivotal arrangement.

One wheel (106a, 106b) of the pair is rigidly secured to opposite distal ends of the pivot (40), such that the longitudinal axis of the pivot (40) passes through the rotational axis of each wheel (106a, 106b). Each wheel is separately arranged to engage with a track (1 08a, 1 08b) arranged either side of the mould assembly (10), at selected positions along the apparatus, as the assembly (10) is moved along the conveyor (22). The tracks (108a, lOBb) extend substantially parallel to the conveyor (22) and are vertically displaced with respect to each other, with one track (108b) being positioned to engage with the top of one wheel (106b), while the other track (108a) is arranged to engage with the bottom of the other wheel (106a).

The tracks (108a, 108b) are spaced along the conveyor (22) and positioned at regions where the mould assembly (10) is required to open and close. The pivot (40) is rigidly coupled to one of the mould elements, for example the second mould element (14) such that as the bottom of wheel (106a) engages with track (108a), the mould element (14) is caused to rotate away from mould element (12) that is fixed upon the conveyor (22). As wheel (106a) moves off track (107a), the top of wheel (106b) is arranged to engage with track (108b) so as to cause second mould element (14) to rotate toward the first mould element (12) and thus close the cavity. The length of track (108a) is chosen to determine the extent of the opening of the assembly (10) and the length of track (108b) is matched with that of track (108a) to ensure the assembly (10) closes sufficiently without any overpressure being exerted between the mould elements (12, 14).

To ensure that there is no slipping of the wheels (106a, 106b) upon the respective tracks (lOBa, 108b), the wheels (106a, 106b) comprise a series of serrations or teeth (110) which extend radially of the wheel (106a, 106b) along the circumference thereof, and are arranged to cooperate with apertures (not shown) arranged within the respective track (107a, 107b).

Once the wheels (106a, 106b) move off the respective track (107a, 107b), then in order to ensure that the mould elements (12, 14) remain in a closed configuration, a hook (112) that is rotatably coupled to a side edge of one of the mould elements (12, 14) is arranged to engage with a barb (114) arranged on the corresponding side edge of the other mould element (12, 14). The hook (1 12) and barb (1 14) cooperate to lock the mould assembly (10) closed. This helps to maintain the pressure upon the moulding compound (37) within the assembly (10) as the assembly is vibrated and also to retain any heat within the assembly (10) as it moves along the conveyor (22).

When the mould elements (12, 14) are required to rotate with respect to each other to open the assembly (10), a further arm (not shown) is arranged to disengage the barb (114) from the projection (112).

Claims

<claim-text>CLAIMS1. Moulding apparatus comprising mould means, the mould means comprising first and second mould elements which are mounted for movement between a closed position in which together they provide the surfaces of a closed moulding cavity contained between the elements, and an open position, the apparatus further comprising conveyor means for conveying the mould means through operating zones in which the moulding cavity is charged with a moulding compound, the moulding compound is processed to convert the moulding compound into a three dimensional article and the mould elements are caused to move to their open position to enable removal of the three dimensional article, the apparatus further comprising means for controlling relative movement of the first and second elements between the open and closed positions as the mould means is conveyed by the conveyor means.</claim-text> <claim-text>2. Apparatus according to claim 1 wherein the means for controlling relative movement of the first and second mould elements between the open and closed positions as the mould means is conveyed by the conveyors means comprises guide means which defines the locus of movement of a portion of the second mould element as the mould means is conveyed by the conveyor means.</claim-text> <claim-text>3. Apparatus according to claim 2 wherein the guide means comprises a continuous looped guide channel mounted parallel to a portion of the conveyor means and divergent therefrom at one or more locations to an extent to enable the mould elements to occupy their open position.</claim-text> <claim-text>4. Apparatus according to claim 1, wherein the means for controlling relative movement of the first and second elements between the open and closed positions as the mould means is moved by the conveyor means comprises hinge means which couples the first and second element together to permit the elements to rotate with respect to each other to open and close the mould means.</claim-text> <claim-text>5. Apparatus according to claim 4, wherein the hinge means is rigidly secured to one of the mould elements and rotatably secured to the other mould element.</claim-text> <claim-text>6. Apparatus according to claim 5, wherein one end of the hinge means comprises a wheel rigidly secured thereto, for engaging with track means as the mould means is moved by the conveyor means.</claim-text> <claim-text>7. Apparatus according to claim 6, wherein the track means comprises two track elements vertically displaced with respect to each other.</claim-text> <claim-text>8. Apparatus according to claim 7, wherein the wheel engages with one track element on the under side of the wheel and the other track element on the upper side of the wheel.</claim-text> <claim-text>9. Apparatus according to claim 7 or 8, wherein the track elements are separated along the length of the conveyor means such that the wheel engages with only one track element at a time to open and close the mould means.</claim-text> <claim-text>10. Apparatus according to claim 5, wherein the hinge means comprises a wheel rigidly secured at either side thereof for separately engaging with a track element arranged either side of the mould means.</claim-text> <claim-text>11.Apparatus according to claim 10, wherein the track elements are separated along the length of the conveyor means such that only one wheel engages with a track element at a given time.</claim-text> <claim-text>12. Apparatus according to claim 10 or 11, wherein the track element arranged at one side of the mould means is vertically displaced with respect to the track element arranged at the other side of the mould means.</claim-text> <claim-text>13. Apparatus according to claim 12, wherein the wheel arranged at the one side of the hinge means engages with the track element arranged on the one side, on the bottom of the wheel and the wheel arranged at the other side of the hinge means engages with the track element arranged on said other side, on the top of the wheel, to open and close the mould means.</claim-text> <claim-text>14. Apparatus according to any preceding claim wherein the mould means comprises one or more mould assemblies comprising said mould elements.</claim-text> <claim-text>15. Apparatus according to any preceding claim comprising means for applying vibration to the mould means.</claim-text> <claim-text>16. Apparatus according to claim 15 wherein the means for applying vibration are arranged to vibrate the mould means when the mould elements are moved from their closed position to their open position.</claim-text> <claim-text>17. Apparatus according to claim 15 wherein the means for applying vibration are arranged to vibrate moulding compound introduced to the cavity and/or prior to the mould elements occupying their closed position.</claim-text> <claim-text>18. Apparatus according to any preceding claim wherein the mould elements occupy their open position to enable insertion of moulding compound to the moulding cavity.</claim-text> <claim-text>19.Apparatus according to any preceding claim further comprising a feed mechanism for introducing the moulding compound to the mould cavity formed by the mould elements.</claim-text> <claim-text>20.Apparatus according to claim 19, wherein the feed mechanism comprises a mould filling station comprising a chamber for holding the moulding compound and at least one pipe extending therefrom which can communicate with the moulding cavity of the mould means so that moulding material can be transferred to said cavity.</claim-text> <claim-text>21. Apparatus according to claim 20, wherein the mould filling station is arranged to rotate about a central axis at a speed so that the at least one pipe can communicate with at least one aperture formed in the mould elements.</claim-text> <claim-text>22. Apparatus according to claim 21, wherein the at least one pipe and/or the at least one aperture in the mould elements comprise non-return valves.</claim-text> <claim-text>23. Apparatus according to any of claims 20 to 22 wherein vibrational members act on at least one of the mould elements as the mould cavities are being filled with moulding compound.</claim-text> <claim-text>24. Apparatus according to claim 23, wherein a first set of vibrational members is arranged to vibrate the first of said mould elements and a second set of vibrational members is arranged to vibrate the second mould element.</claim-text> <claim-text>25. Apparatus according to claim 24 wherein there is a greater number of vibrational members associated with the second set than the first set.</claim-text> <claim-text>26. Apparatus according to any of claim 19 or 20, comprising a first and second feed mechanism both arranged to feed moulding compound into the mould cavity.</claim-text> <claim-text>27. Apparatus according to claim 26, wherein the first feed mechanism is arranged up-stream of the second feed mechanism, the first feed mechanism being a mould filling station as claimed in claim 21, the second feed mechanism being a feed mechanism that introduces material into the mould cavity as the second mould element is caused to open.</claim-text> <claim-text>28. Apparatus according to any preceding claim wherein the conveyor means comprises an endless chain.</claim-text> <claim-text>29. Apparatus according to claim 28 wherein the endless chain comprises one or more areas where the chain is arranged in a looped configuration.</claim-text> <claim-text>30. Apparatus according to claim 29, wherein the looped configuration(s) of chain is contained within a housing.</claim-text> <claim-text>31. Apparatus according to claim 30, wherein the housing comprises control means for controlling the flow of gases released from the mould means and contained within the housing.</claim-text> <claim-text>32. Apparatus according to claims 30 or 31, wherein the housing comprises venting means to release gas from the housing.</claim-text> <claim-text>33. Apparatus according to claim 32 wherein the venting means comprises gas scrubbers.</claim-text> <claim-text>34. A mould assembly comprising first and second mould elements which are connected together by hinge means and which are arranged to occupy a closed position in which together they provide the surfaces of a closed moulding cavity contained between the mould elements, and an open position for providing access to the cavity, the mould means further comprising means for cooperating with conveyor means to permit the mould assembly to be conveyed by the conveyor means and means for opening and closing the moulding cavity as permitted by the hinge means, as the mould means is conveyed by the conveyor means.</claim-text> <claim-text>35.A mould assembly according to claim 34 wherein the means for opening and closing the moulding cavity comprises guide means which defines the locus of movement of a portion of the second mould element as the mould means is conveyed by the conveyor means.</claim-text> <claim-text>36. A mould assembly according to claim 35 wherein the guide means comprises a continuous looped guide channel mounted parallel to a portion of the conveyor means and divergent therefrom at one or more locations to an extent to enable the mould elements to occupy their open position.</claim-text> <claim-text>37. A mould assembly according to claim 34, wherein the means for opening and closing the moulding cavity comprises a wheel rigidly secured to the hinge means for engaging with track means as the mould means is conveyed by the conveyor means.</claim-text> <claim-text>38. A mould assembly according to any of claims 34-37 comprising means for vibrating a mould element.</claim-text> <claim-text>39. A mould assembly according to claim 38, wherein the means for applying vibration to the mould assembly comprises vibrational members associated with each of the mould elements.</claim-text> <claim-text>40. A mould assembly according to claim 38 or claim 39, wherein a first set of vibrational members is arranged in communication with the conveyor means and is arranged to vibrate the first of said mould elements, and a second set of vibrational members is arranged in communication with the second mould element for vibrating the second mould element.</claim-text> <claim-text>41. A mould assembly according to any of claims 34-40 further comprising means for heating the first and second mould element.</claim-text> <claim-text>42.A mould assembly according to claim 41, wherein the means for heating each mould element comprises an electrical heating element.</claim-text> <claim-text>43.A mould assembly according to claim 41, wherein the means for heating each mould element comprises a heated fluid flowing through ducts in the first and second mould elements.</claim-text> <claim-text>44. A mould assembly according to any of claims 34-43 further comprising a sensor for detecting the relative position of said first and second mould elements.</claim-text> <claim-text>45. A mould assembly according to claim 44, wherein the sensor comprises an infra-red sensor.</claim-text> <claim-text>46. A mould assembly according to claim 44 or 45 wherein the sensor is in communication with a controller that can operate an alarm if the sensor detects undesirable values for the position/condition of the first and/or second mould element.</claim-text> <claim-text>47. A mould assembly according to any of claims 34-46 wherein one of the first or second mould elements comprise an aperture through which moulding compound can be delivered to the moulding cavity, when the first and second mould elements are in a closed position.</claim-text> <claim-text>48. A mould assembly according to claim 47 wherein the aperture includes a non-return valve.</claim-text> <claim-text>49. A mould assembly according to any of claims 34-48 wherein the first and second mould elements further comprise means for cooling each of said mould elements.</claim-text> <claim-text>50. A method of producing moulded articles, the method comprising the use of the apparatus of any of claims 1-33.</claim-text> <claim-text>51. A method of producing moulded articles, the method comprising the use of the mould assembly of any of claims 34-49.</claim-text> <claim-text>52. Moulding apparatus substantially as herein described and with reference to the accompanying drawings.</claim-text> <claim-text>53. Mould assembly substantially as described herein and with reference to the accompanying drawings.</claim-text> <claim-text>54. A combined moulding apparatus and mould assembly as described herein! with reference to and as illustrated in the accompanying figures.</claim-text>