IE55687B1 - Installation for the pressing of fibre cement sheets - Google Patents

Abstract

1. Apparatus for the compression of fibrous-cement slabs (1), which initially lie in the form of a fibrous-cement mat centrally on a pressing base (2), with symmetrically arranged lateral handling surfaces (3) and between the latter, and are transported into a compression station (4) of a press (5) and thereafter are transported as compressed plates out from the compression station on the pressing base by means of a conveying device (6), which to receive the pressing bases (2) with the plates (1) has two conveyor belts (8) running parallel to each other along the compression station (4), on which belts the pressing bases (2) come to be transported lying freely, a drive device (10) being associated with the belts (8), characterized in that the relative distance and the width of the belts (8) correspond to the distance and the width of the handling surfaces (3) of the pressing bases, and that the belts (8), which are both identical, are provided with engagement sections (9) which are fixed to the belt and follow each other at regular intervals along the length of the belts, the drive device (10) having engagement elements (11) which are constructed corresponding to the engagement sections (9) and engage in the engagement sections, and being designed for synchronous movement of the two belts (8), i.e. at the same speed at the same time.

Description

The invention relates to apparatus for the compression of fibrous-cement slabs, vMch slabs are initially placed, in the form of a fibrous-cement mat, centrally on a pressing base having lateral handling surfaces, the mat being symmetrically arranged between the said lateral handling surfaces, and which are transported into a compression station of a press and thereafter are transported as compressed plates out from the compression station on the pressing base by means of a conveying device, which to receive the pressing bases with the plates has two conveyor belts running parallel to each other along the compression station, cm which belts the pressing bases came to be transported lying freely, a drive device being associated with the belts.

In a contemporary continuous production process of fibre cement sheets, a prefabricated fibre cement mat is transferred onto a press-plate advanced to it. The Loaded plate is conveyed to a press, into a pressing place and, positioned there, pressed with the mat. After the pressing operation, the plate with the pressed sheets is conveyed out of the pressing place. Subsequently, the sheet is removed from the base and the empty plate is conveyed back to the start of the installation, to be reloaded there with a fibre cement mat to be pressed. Usually, a number of press plates circulate in the process at a rate of, for example 3 m/sec and in a sequence of, for example, 12 seconds. In this case, such an installation operates automatically and, for safety reasons, an intervention by human hand is impossible. Uninterrupted production around the clock is demanded. Consequently, high demands are made on the reliability of the conveying of the press plate and of the loaded press plate in 2 particular with respect to an exact positioning in relation to the handling or manipulation stations mentioned of the installation. One of the reasons why reliable conveying is difficult is that the circulating 5 press plates are impaired, mainly during pressing, and have to be conveyed in a more or less deformed condition, for example they are no longer ideally flat.

It has been attempted to provide suitable conveying by using drag chain conveyors. These proved 10 to be not very satisfactory. Because of the varying and, mainly due to wear, unpredictably ever increasing play between the chain links, it is technically impossible to achieve synchronous running of a pair of drag chains parallel at certain points. Furthermore, the frequently 15 unflat, damaged plates have to be held to the chain conveyors by means of complicated grips. It is hardly possible to achieve an exact positioning with these conveying devices, the plates often tilt in relation to the intended conveying path. For all of these reasons, 20 the process sequence is disturbed and this results in interruptions in production until the damage, or the cause of the damage, is eliminated.

Similar difficulties were encountered when it was attempted to provide the conveying device with customary 25 conveyor belts. In this case, it was not possible to achieve parallel synchronous running of a pair of belts, mainly due to unavoidable slip between the drive and the belt. In start-up and braking there was also slipping of the plates or tilting, which made exact positioning 3 impossible. A device of the type described above is shown in FR-A-22 89 329.

Finally, loading trolleys moving back and forth between two stations, as known for example from German Offenlegungsschrift 3 146 813, also come into consideration. This conveying device appears to be technically e laborate.

The object of the invention is to propose a conveying system, improved with respect to those known thus far, for an installation of the type described at the start. In particular, it is intended to avoid tilting or sliding of the press plates to be conveyed and thereby to ensure their exact positioning, without collision, in the individual handling or manipulation stations. The conveying device should be relatively simple and also usable for installations with presses having two pressing places or decks arranged one above the other.

In order to achieve this object, it is proposed according to the invention that the relative distance and the width of the belts correspond to the distance and the width of the handling surfaces of the pressing bases, and that the belts, which are both identical, are provided with engagement sections which are fixed to the belt and follow each other at regular intervals along the length of the belts, the drive device having engagement elements which are constructed corresponding to the engagement sections and engage in the engagement sections, and being designed for synchronous movement of the two belts, i.e. at the same speed at the same time.

This provides for synchronous running of the two conveyor belts relative to each other at certain points so that tilting cannot occur and trouble-free conveying with exact positioning in the particular station is ach i eved.

A preferred embodiment is provided by designing the conveyor belts as toothed belts, the regularly arranged teeth of which form the engagement points, with drive gears, toothed corresponding to the division and tooth shape of the toothed belt, being provided and forming the engagement elements of the drive device.

Such toothed belts are commercially available and the conveying device fitted with them operates reliably and practically maintenance free.

In the following text, an installation according to the invention and its advantages are described in more detail and explained. The description refers to the following figures in the drawing, in which Figure 1 shows, diagramaticalLy from the side, an installation for pressing fibre cement sheets having conveying devices according to the invention. Figure 2 shows a detail of the conveying device.

Figure 3 shows a waiting station of the conveying device.

The installation shown in figure 1 is for pressing fibre cement sheets 1- Initially in the form of a fibre cement mat, the Latter lie, as shown in figure 2, on a press plate 2, which has laterat manipulation areas 3 5 arranged symmetrically parallel. The sheet 1, therefore lies between the manipulation areas.3. The plate 2 is perforated in the region covered by the sheet 1, to carry away the liquid pressed out during pressing of the mat. When pressing corrugated fibre cement sheets/ the plate 2 is corrugated in the region. The manipulation areas 3 are, in each case, flat and lie on the same level.

By means of a conveying device, which is denoted generally by 6, the plate 2 with the sheet 1 is conveyed into a pressing place 4 of a press 5 and, after pressing has been performed, if the sheet 1 has been completely pressed, the plate 2 with the sheet 1 is conveyed out of the pressing place 4.

The pressing place takes the form of press rams 7, which cover the extent of the sheet 1, so that the manipulation areas 3 of plate2 lie outside and parallel along the pressing place, when the sheet 1 with the plate 2 is positioned in the pressing place 4.

To receive the individual pressplates 2 with the sheet 1, the conveying device 6 has two conveyor belts 8, as is shown particularly clearly in figure 2. The belts run parallel to each other along the pressing place 4 and through the press 5. The spacing between the belts 8 and their width correspond to the relative spacing and width of the manipulation areas 3 of the press plates 2. Along their length, the belts 8, both the same, are provided with engagement points 9 successively arranged at regular intervals and in fixed position with respect 6 to the belt 8. These conveyor belts 8 have an associated drive device 10/ which has engagement elements 11 which correspond to the engagement points 9 and engage in the engagement points. The drive device 10 is designed for the synchronous movement of the belts 8. It therefore serves to move the belts 8 at the same speed and at the same time.

As exemplified by this example, and as indicated in figure 2, the conveyor belts are designed as toothed belts, the teeth 9 of which, arranged at regular intervals length-wise, form the engagement points. Associated with each toothed belt 8 the drive device 10 has a drive gear 11, which is toothed correspondingly to the pitch and tooth shape of the toothed belt 8 and forms the engagement element mentioned. As is also revealed by figure 2, only one side of the toothed belt 8 is toothed and the other side is smooth. It can be seen that the toothed side of the toothed belt 8 is made to face a press plate 2 to be conveyed, which is conveyed resting freely on the toothed belt 8.

In order to achieve an absolutely slip-free drive of the toothed belt 8, the toothed belt 8 is guided by means of two deflection rolls 12, so that it forms a loop about the drive gear 11. This produces wrapping of the belt about 180°. The deflection rolls 12 simultaneously act as tension rolls for the toothed belt 8.

It has been shown that a toothed belt made of reinforced plastic is best suited for this conveying device. Its smooth side should have good sliding properties with 7 respect to a guiding base 13, which is provided for its guidance and is made, for example, of plastic. Such a toothed belt is commercially available. It is also conceivable to provide a liquid film, e.g. a hydrostatically developed liquid layer, between the toothed belt 8 and the guiding base 13, in order to achieve non-wearing conditions in the present case.

Synchronisation of the two toothed belts, which form a co-operating pair, is achieved in a simple way by driving the associated drive gear pair by a common shaft, which is coupled up to a drive motor M.

In this conveying device described, the two toothed belts 8 move absolutely synchronously and in conformity. This means that there is no momentary relative displacement at certain points of one toothed belt with respect to the other in the pair. The relatively heavy press plate 2 with the sheet 1 rests freely, but nevertheless without sliding, on the toothed belt and cannot be displaced and/or tilted due to the momentary delay or running ahead of one belt with respect to the other, and can thus be exactly positioned at a desired place along the conveying path.

In order to increase the adhesion between the conveyor belt 8 and the press plate 2, the facing, or contacting surfaces of the conveyor belts 8 and the manipulation areas 3 of the press plates 2 are provided with a gripping surface; in the case of toothed belts, it is sufficient if this is only on the manipulation areas. This ensures that the press plate rests on the belts without 8 slipping.

In order to be able to control conveying variously and as is desirable in the individual sections along the conveying path, the conveying device 6 is sub-divided into three sections: one section 6^, which leads through the press 5, has a section which acts as a waiting station, upstream of it and a section 6^, which acts as a depositing station, downstream of it. Each of the three sections 6^, 6^, 63 has in its region a pair of conveyor belts 8^, 83. Each pair is driven separately from the other and is equipped with its own, individually 1 2 commanded and controllable drive device 10 , 10 , 103. Each drive device is driven by means of its own, independently commanded and controllable direct current motor H.

The installation shown in figure 1 is fitted 1 2 with a press 5 having two pressing places or decks 4 and 4 arranged one above the other. This press presses two sheets at once in an operating cycle. Each of the pressing places 4^ and 4^ has an associated conveying device 6. Thus, conveying the press plates 2 with the sheets 1 takes place simultaneously and in the same cycle in a lower and in an upper tier with respect to the press. The upper tier is shown in the drawing by broken lines.

Prefabricated fibre cement mats are laid on the press plates in a loading station 14. The plate lies on a 9 conveyor belt 15 of the station and waits there until the mat has been put on.

The completed pressed fibre cement sheets are removed from the press plates and taken into an unloading station 16 on the left of the figure, lying on a conveyor belt 17 of the station. The conveyor belts 15 and 17 of the loading station and of the unloading station, respectively, are on the same level as the lower conveying tier mentioned above.

Each alternate loaded press plate coming from the loading station is raised from the level of the lower tier to the level of the upper tier, mentioned above, and after pressing, lowered to the level of the lower tier. This happens in the region of the waiting station and in the region of the depositing station 6^, respectively. A waiting station and a depositing station, respectively, for this purpose are shown in more detail in fig.3. The conveyor belts 8 of the upper tier are arranged in a laterally displaceable mounting on a frame 20, so that the relative spacing between the belts can be enlarged over the width of the press plate if the belts are in this spread position, the press plate can be conveyed between them in the vertical direction. This vertical conveying is carried out by a lifting platform having a horizontal platform plate 21, which can be changed by means of a lifting device 22 into an upper position above the level of the upper tier and into a lower position beneath the level of the lower tier.

The installation operates in the following operational steps: A first press plate’ has been loaded onto the conveyor belts 15 of the loading station, lying on them with the mat. to be pressed.

After simultaneous movement of the belts 15 and of the adjoining belts 82, the plate is positioned in the waiting station 62 on the lower belts 82.

The platform plate 21 is in its lower position.

The upper conveyor belts of the waiting station 62 are spread and are in the position shown at the top right of fig.3, so that the plate can be conveyed between them.

The platform plate 21 moves into its upper position and lifts the plate above the level of the upper tier.

The upper belts return and are located underneath the manipulation areas of the plate This position can be seen at the top Left of figure 3.

The platform plate 21 returns to its lower position and the first plate comes to rest on the upper belt.

A second plate which has been loaded in the meantime, arrives in the lower tier of the waiting station 62.

The pressing places for 4^ and 42 of the press 5 open.

By means of simultaneous movement of the conveyor belts 8^ and 82 of the two tiers, the first and second loaded platesare positioned in the respective pressing places. 11 The pressing operation is accomplished and the pressing places 4^ and 4^ are opened.

By means of simultaneous movement of the belts and the adjoining belts of the two tiers, the first and second plates are simultaneously moved into the depositing station and positioned there. At the same time, the belts and 8^ convey the next two waiting plates on the two tiers into the pressing places 4^ and 4^.

The plate located on the lower tier is taken into the unloading station 16 by simultaneous movement of the lower belts 8^ and the adjoining belts 1? and the pressed sheet is removed from the base.

The emptyplate is conveyed via a conveying path (not showr) back to the loading station 14.

The platform plate 21 in the depositing station moves into its upper position and thereby lifts the plate lying up until this time on the upper belts.

The upper belts thus relieved are spread apart and the platform plate 21, with the press plate Lying on it, subsequently turns to its lower position. The plate is thus transferred onto the belts of the lower tier of the depositing station 6^.

The upper belts return to their closed position and are therefore ready to receive another press plate By means of simultaneous movement of the lower belt 8^ and the adjoining belt 17, the plate, transferred from above to below is taken into the unloading station and, after removal of the fibre cement sheet the empty 12 plate is conveyed via the conveying path mentioned above back in the direction towards the Loading station 14.

The instalLation operates continuously and the described conveying of the plates is controlled to 5 synchronise with the cycle of the press 5. The loading and unloading of the plates in the stations 14 and 16 takes place at half the cycle. Transferring each alternate plate from one tier to the other in stations and also takes place within the period of 10 half a cycle.

The conveying devices in stations 14 and 16, i.e. the conveyor belts 15 and 17, respectively, and the drive devices 18 and 19, respectively, are also designed in the manner of the invention described. Suitable 15 return conveying of the empty plates is also provided by the same means.

Claims (13)

1. Apparatus for the compression of fibrous-cement slabs, which slabs are initially placed, in the form of a fibrous-cement mat, centrally on a pressing base having lateral handling surfaces, the mat being symmetrically arranged between the said lateral handling surfaces, and which are transported into a compression station of a press and thereafter are transported as compressed plates out from the compression station on the pressing base by means of a conveying device, which to receive the pressing bases with the plates has two conveyor belts running parallel to each other along the compression station, on which belts the pressing bases come to be transported lying freely, a drive device being associated with the belts, wherein the relative distance and the width of the belts correspond to the distance and the width of the handling surfaces of the pressing bases, and wherein the belts, which are both identical, are provided with engagement sections which are fixed to the belt and follow each other at regular intervals along the length of the belts, the drive device having engagement elements which are constructed corresponding to the engagement sections and engage in the engagement sections, and being designed for synchronous movement of the two belts, i.e. at the same speed at the same time.

2. Apparatus according to Claim 1, wherein the conveyor belts are constructed as toothed belts, the regularly arranged teeth of which form the engagement sections, driving cogwheels being provided, which are toothed corresponding to the spacing and tooth form of the toothed belts and which form the engagement elements of the drive device.

3. Apparatus according to Claim 2, wherein only one side of the toothed belt is toothed, and its other side is smooth, and wherein the toothed belt faces with its toothed side a pressing base which is to be transported, which is transported lying freely on the toothed belt.

4. Apparatus according to Claim 3, wherein the toothed belt is arranged for driving by means of two guide rollers, and is guided to form a loop around the driving cogwheel.

5. Apparatus according to Claim 3, wherein the toothed belt is of reinforced synthetic material, and the smooth side of the toothed belt has good sliding properties with respect to a guide base for the toothed belt.

6. Apparatus according to Claim 1, wherein the conveying device is divided into three sections, a stand-by station being arranged in front of a section leading through the press, and a depositing station being arranged thereafter, which three sections in each case have in their area a pair of the conveyor belts, and each section is equipped for itself with its own expressly commanded and adjustable drive device.

7. Apparatus according to Claims 1 to 6, wherein a press with two pressing sections are arranged one over the other, and each of the pressing sections is associated with its own conveying device.

8. Apparatus according to Claims 7 or 6 respectively, in which the conveying devices in each case have a 5 stand-by station and a depositing station, wherein the upper pairs of the conveyor belts are arranged so as to be laterally slidably mounted in the stations, to increase the relative distance of the belts over the width of the pressing base, so that with this 10 increased distance the pressing base is able to be transported through between the belts in a vertical direction, and wherein lifting devices are provided at the stations for this transportation.

9. Apparatus according to one of Claims 1 to 8, 15 wherein the drive devices in each case are equipped with their own, expressly commanded and adjustable direct-current motor.

10. Apparatus according to Claim 2, wherein for a pair of toothed belts there is provided a pair of 20 driving cogwheels which are driven in synchronism by a common shaft which is coupled to a driving motor.

11. Apparatus according to Claim 1, wherein the conveyor belts have a gripping surface which renders difficult relative slipping of the pressing bases 25 which are to be transported, which surface faces the handling surfaces, the handling surfaces also having a correspondingly constructed surface on their side facing the conveyor belts, for non-slip contact between the conveyor belts and the pressing bases.

12. An apparatus for the manufacture of fibre cement sheets, substantially as described with reference to and as shown in the accompanying drawings. MACLACHLAN & DONALDSON Applicants' Agents,

13. 47 Merrion Square, DUBLIN 2.