AUTOMATIC BELLING MACHINE AND METHOD FOR BELLING PIPES MADE OF THERMOPLASTIC MATERIAL

Technical field

This invention relates to a belling machine for pipes made of thermoplastic material, that is, a machine designed to deform into the shape of a bell at least one end of a pipe made of thermoplastic material. In particular, the invention relates to a belling machine for thermoplastic pipes comprising a device for moving pipes.

The invention also relates to a method for belling pipes actuated by the above-mentioned automatic belling machine. Background art

In the production of pipes made of thermoplastic material by extrusion designed for making pipes for supplying and/or draining fluids, the most commonly used thermoplastic materials are unplasticised polyvinyl chloride (PVC-U), polypropylene (PP) and high-density polyethylene (HDPE).

More specifically, the invention is particularly useful in the context of the production of pipes used in the systems of pipes installed in the drains inside buildings.

The drainage pipes in buildings are characterised by smaller outside diameters (between 32 mm and 160 mm) and smaller lengths (between 150 mm and 3000 mm) compared with pipes for underground drains and supplying fluids (whose length, for example, is never less than 500 mm). The wall thickness of drain pipes in buildings is generally 2 to 5 mm. Generally speaking, these pipes have at least one bell-shaped end, that is to say, they have at their end portion a transversal cross-section which is wider than the transversal cross-section along the longitudinal extension of the pipe. This wider shape is used to connect the pipes in succession with each other which form a conduit.

In general, a non-widened end of a pipe, preferably with a bevelled edge, is inserted in the bell-shaped end of the adjacent pipe in the conduit.

In order to give the bell shape, the prior art systems for the production of pipes comprise belling machines used for shaping an end portion of the pipes.

The automatic belling machine can be installed in an extrusion line of the pipes and, in line, receive the pipes or pieces of cut pipe to be shaped.

The majority of belling machines make the bell with the hot forming process.

The machines are equipped with one or more heating stations suitable to heat the end of the pipe, changing the wall to be shaped into a plastically deformable softened state.

Subsequently, a forming station, preferably equipped with a suitable mould, forms the heated end of the pipe into a bell shape and cools the bell shaped on the mould.

A widespread application is the shaping of the end of the pipe by moulding with a spindle, also called a pad, as illustrated in patent document EP 0 700711 B1 in the name of the same Applicant.

The spindle, or pad, reproduces the internal shape of the bell to be shaped and is inserted inside the pipe at the end to be shaped to form the end of the pipe into a bell shape.

In order to increase productivity, the belling machines used in current plants comprise multi-belling stations, that is to say, stations which are able to process groups of at least two pipes simultaneously thanks to a multiplication of the elements in the stations, in particular those for heating and forming.

Depending on the number of ends shaped in the form of a bell, there are two types of pipes: the single bell pipes, if only one end is bell-shaped, and the double jointed pipes, when both ends of the pipe are widened. The making of double jointed pipes results in the need for a second belling operation, to be carried out on a single joint pipe, that is to say, the semi finished pipe having a single end shaped in the form of a bell and the other end still unfinished and generally not bevelled.

Currently, in the systems for making pipes made of thermoplastic material, at least two belling machines are provided for making double jointed pipes, each configured for forming an end of the pipe into a bell shape, so as to keep the production efficiency almost unchanged.

Some solutions comprise the use of two belling machines facing each other so as to simultaneously shape the two ends of the pipe.

Often, however, mixed production of pipes is adopted in the production plants, that is to say, pipes are produced with different lengths.

In these solutions of belling machines facing each other, a variation in length between one pipe and another makes a solution with two belling machines facing each other impossible, since the pipes of smaller length could not undergo the belling operations at one end.

Other solutions involve the use of two belling machines located in series along the production line, in such a way as to perform the belling operations in two separate stages of the process for production of the double jointed pipes.

The second belling machine can be rotated by 180° relative to the first or maintain the same orientation and, in the latter case, a rotation of the pipe is performed during the step for conveying the pipe between the first and the second belling machine.

These solutions allow the production of pipes with mixed lengths and the general production efficiency of the plant to be kept practically unchanged. However, the arrangement of the two belling machines results in a considerable increase in the overall dimensions of the production plant, due to the overall dimensions of the second belling machine and of the transport line between the two belling machines.

Moreover, the production of pipes often not only have variations in the lengths of the pipes, but also in the types of pipes, that is to say, there can be production plants which comprise the simultaneous production of single bell pipes and double jointed pipes.

The combined production of single bell pipes and double jointed pipes cannot be performed with the solutions described above with two belling machines.

In addition, a drawback shared by all the solutions described above is the increase both in the costs for setting up the production plant, since two belling machines must be produced/purchased and in the management costs of the plant, since there is a further energy-consuming element.

The presence of two belling machines also results in an increase in the complexity of the production plant, with the addition of an additional element which requires maintenance and may be subject to malfunctions. Patent document US3849052A describes a belling machine for thermoplastic pipes having an elongate frame which uses a plurality of chain conveyors. The chain conveyors carry spaced pins for transporting the pipes.

Patent document US4218208A describes a further belling machine equipped with revolving clamps to receive an end of a heated pipe.

Patent document US2019202108A1 in the name of the same Applicant as this invention describes a further belling machine for thermoplastic pipes equipped with a station for thermoforming one end of the pipe and further stations, and with a device for positioning the pipe for moving the pipe between the different stations.

Disclosure of the invention

The machine and the method according to the invention aim to overcome the above-mentioned drawbacks.

More specifically, the invention provides an automatic belling machine for pipes made of thermoplastic material which is particularly versatile, with considerably reduced costs and overall dimensions compared with prior art belling solutions.

This invention provides a method for belling pipes made of thermoplastic material which is particularly efficient.

These aims and others, which are more apparent in the description which follows, are achieved by a belling machine and a method for belling pipes made of thermoplastic material comprising the technical features described in one or more of the appended claims.

Brief description of drawings The technical features of the invention, according to the aforesaid aims, are clearly disclosed in the claims below, and their advantages will become more evident in the detailed description that follows, with reference to the accompanying drawings which represent one embodiment provided as a non-binding example, wherein: - Figure 1 is a partial perspective view of a pipe made of thermoplastic material with a bell-shaped end;

- Figure 2 is a partial cross section of the joint between two pipes made of thermoplastic material, one having a bell-shaped end and the other having a bevelled end and inserted in the bell-shaped end; - Figure 3 is a perspective view of the belling machine according to the invention according to an embodiment with some parts removed for greater clarity;

Figure 4 is a top view of the belling machine of Figure 3;

Figure 5 is a front view of the belling machine of Figure 3; - Figure 6 is a side view of the belling machine of Figure 3;

Figure 7 is a block flow diagram of the steps of the belling method according to the invention;

- Figure 8 illustrates, with reference to the belling machine according to a front view, the sequence of the steps of the belling method of Figure 7;

- Figure 9 illustrates a sequence of steps, from a) to I), indicating an example of the sorting process of the belling machine.

Detailed description of preferred embodiments of the invention

With reference to the accompanying drawings, the numeral 1 denotes a belling machine designed to be installed in a plant for producing pipes T made of thermoplastic material.

The main purpose of the belling machine 1 is to deform the pipes T at a relative end T1 , T2 so as to give a bell shape B at the end T1 , T2.

This method takes the conventional name of belling.

As illustrated in Figure 1 , the bell shape B of the end T1, T2 of the pipe T results in a widening of the transversal cross-section of the pipe T.

The aim of this deformation of the end T1 , T2 of the pipe T is to allow the connection between two pipes T, by means of a shape coupling, commonly known by the term "bell joint".

As illustrated in Figure 2, at the end T1, T2 shaped in the form of a bell of a first pipe T the end T1 , T2 without the shape of a bell of a second pipe T is partly inserted, so as to create a connection between the two pipes. Preferably, the end T1 , T2 not bell-shaped has a bevel S, so as to facilitate the partial insertion of the end inside the bell -shaped end T1 , T2. Preferably, the bevel S is always present when an end T1 , T2 is not designed to adopt the bell shape B.

Preferably, a seal G is inserted, at the bell-shaped end.

The seal G, generally made of rubbery material with a high friction coefficient, guarantees the hermetic seal of the bell joint.

Preferably, the pipes T made of thermoplastic material comprise at least one of the following components: unplasticised polyvinyl chloride (PVC-U), polypropylene (PP) and high-density polyethylene (FIDPE).

The belling machine according to the invention is generally installed inside plants for the production of pipes made of thermoplastic material.

The machine is positioned downstream of a station for extruding a casting of thermoplastic material and a station for cutting said casting of thermoplastic material.

The dimensional characteristics, in particular in terms of diameter and length of the pipes, are determined by the stations upstream of the belling machine 1 , which receives as input pipes T with lengths and diameters designed to remain unchanged except for the ends T1 , T2.

The belling machine according to the invention is particularly suitable for belling of drain pipes for buildings, that is to say, pipes characterised by diameters of between 32 mm and 160 mm and lengths from 150 mm to 3000 mm. The belling machine may, however, also be used for belling pipes for underground drains and water supply, which are characterised by larger diameters and lengths.

Depending on the number of ends to be shaped in the form of bells there are two types of pipes: the single bell pipes, if only one end T1 or T2 is designed to adopt the bell shape B, and the double jointed or double- belled pipes, when both the ends T1 , T2 of the pipe T are intended to undergo a belling process.

It is customary not to calculate, for the length of the finished pipe T, the portion of pipe T subjected to the belling operations. Thus, in the case of single bell pipes with a length of 150 mm, the length of the finished pipe T is 150 mm + 70 mm, where 70 mm is the length of the portion of pipe T having the bell shape B.

On the other hand, for the pipe not yet subjected to belling in the same example case, the length is 150 mm + 70 mm + 15 mm, where the portion of 15 mm consists of the quantity of thermoplastic material necessary to compensate for the widening of the cross-section caused by the belling operation.

In the case of double jointed pipes, the additional contributions are counted twice since, with respect to single bell pipes, there is an additional end to be subjected to belling.

The belling machine 1 is particularly useful for application in production processes wherein at least part of the production is represented by double jointed pipes.

As illustrated in Figure 8, the belling machine 1 comprises means 21 for picking up the pipes T.

The belling machine 1 also comprises an infeed zone Z1 for the pipes T. The pick-up means 21 are operatively associated with the infeed zone Z1. In the infeed zone Z1 , the pipes T remain stationary, waiting to be picked up one at a time by the pick-up means 21.

The infeed zone Z1 is in communication at least with a line X for feeding the pipes T, not forming part of the belling machine 1 but forming part of the plant for making pipes made of thermoplastic material.

According to an aspect of the invention, the feed line X feeds the infeed zone Z1 with pipes T which do not have any of the ends T1 , T2 with the shape of a bell B.

More specifically, the feed line X feeds the infeed zone Z1 with a single pipe T at a time, that is to say, multiple and simultaneous feeding of pipes T is not possible in the infeed zone Z1.

Preferably, the belling machine 1 comprises a translation plane 3 for the sliding of the pipes T between the stations of the belling machine.

The translation plane 3 may be defined by one or more elements, which individually or in their entirety define a supporting surface of the pipes T. According to an embodiment, the translation plane 3 comprises a flat surface for the sliding of the pipes T.

According to another embodiment, the translation plane 3 comprises a plurality of rollers for the sliding of the pipes T.

According to another aspect of the invention, the belling machine 1 comprises a station 2 for forming groups of pipes T.

The pick-up means 21 are configured for picking up the pipes T from said infeed zone Z1 , one at a time, and placing them on the translation plane 3 at the station 2 for forming groups of pipes T.

In this description, the term "group of pipes T” or “group of multi-belling pipes" means a group formed by at least two pipes T.

The forming station 2 is configured to retain the pipes T to allow the formation of the groups of pipes T after a number of pick-ups by the pick up means 21 equal to the number of pipes making up the group of pipes T.

More specifically, the pick-up means 21 position the pipes T on the translation plane 3, side by side, parallel to each other.

Preferably, the pick-up means 21 position the pipes T parallel to a first direction D1 on the translation plane 3.

Preferably, the first direction D1 is parallel to the direction in which the pipes T reach the infeed zone Z1 from the feed line X.

The pick-up means 21 position the pipes T, picked up from the infeed zone Z1 , at the forming station 2.

The forming station 2 is configured for retaining the pipes T in position and for forming groups of pipes T.

The groups of pipes T move simultaneously along the translation plane 3 and undergo operations by the stations of the belling machine 1 , which will be described below.

According to an aspect, the belling machine 1 comprises a first motor- driven belt 22 for positioning the pipe T at the infeed zone Z1 , so as to allow the picking up by the pick-up means 21.

The first motor-driven belt 22 is, advantageously, in communication with the feed line X.

Therefore, the first motor-driven belt 22 is configured for regulating the flow towards the infeed zone Z1 of the pipes T coming from the feed line X.

Preferably, the first motor-driven belt 22 has a longitudinal extension parallel to the first direction D1.

More specifically, the motor-driven belt 22 is movable in both directions along its longitudinal direction of extension.

Again as illustrated in particular in Figure 5, the belling machine 1 comprises at least one heating station 4.

Preferably, the at least one heating station 4 is positioned laterally to the forming station 2 of the groups of pipes along a second direction D2.

The second direction D2 is at right angles to the first direction D1 and, preferably, is parallel to the translation plane 3.

The at least one heating station 4 is configured for heating an end T1 , T2 of the pipe T, bringing it to a plastically deformable softened state.

The material and the dimensions of the pipe T often require quite long heating processes. For this reason, so as not to damage the efficiency of the belling machine 1 , the heating process is split, through the arrangement of several heating stations 4.

The embodiment illustrated in the accompanying drawings shows a belling machine 1 comprising two heating stations 4.

Advantageously, the presence of at least two heating stations 4 allows an optimisation of the efficiency of the belling machine 1.

Each heating station 4 comprises at least one heating element for heating the pipes T and bringing them to the softened plastic state.

According to an embodiment, the at least one heating element comprises at least one hot movable element. The hot movable element is configured to travel along a trajectory close to the inside surface of the end T1, T2 of the pipe T to be heated.

According to another embodiment, the at least one heating element comprises a heating oven in which the end T1 , T2 of the pipe T to be heated is inserted, at least partly.

Preferably, the at least one heating station 4 comprises a plurality of heating elements which are able to heat several pipes T in parallel. Advantageously, the presence of several heating elements allows an multiplication of the efficiency of the heating station 4.

In the embodiment illustrated in the accompanying drawings, each of the two heating stations 4 is able to heat the ends of four pipes T simultaneously. That advantageously increases the productivity of the heating stations 4 by a multiplication factor equal to four.

Again as illustrated in Figures 3 to 6, the belling machine 1 comprises a forming station 5.

The forming station 5 is positioned laterally to the at least one heating station 4 along the second direction D2.

More specifically, the forming station 5 is positioned laterally to the at least one heating station 4, on the side opposite the station 2 for forming the groups of pipes.

Said forming station 5 comprises at least one mould 51.

The at least one mould 51 is configured to generate the bell shape B at the end T1 , T2 of said pipe T which has been previously brought to the softened state by the at least one heating station 4.

According to an embodiment, the at least one mould 51 is of the spindle type, known also as pad.

According to this embodiment, the spindle reproduces the internal shape of the bell-shape B to be given to the end T1 , T2 of the pipe T.

To form the end T1 or T2 of the pipe T into a bell shape, the pad is inserted inside the pipe at the end to be shaped, which is softened by the action of the heating elements of the heating station 4.

Generally, the spindle type moulds comprise an outer portion which reproduces the outer shape of the bell shape B to be given to the end T1, T2 of the pipe T and designed to wrap around the outside of the end. Preferably, the forming station 5 comprises a plurality of moulds 51 which are able to form two or more pipes T in parallel.

Advantageously, the presence of several moulds 51 allows a multiplication of the efficiency of the forming station 5.

In the embodiment illustrated in the accompanying drawings, the forming station 5 is able to form the ends T1 or T2 of four pipes T simultaneously. This advantageously increases productivity from the forming station 5 by a multiplication factor equal to four. According to another aspect, the forming station 5 is configured for cooling the bell-shaped portion B of the pipe T, so as to return to the solid state the end T1 , T2 softened by the at least one heating station 4.

According to an embodiment, the forming station 5 comprises aeration systems for generating a jet of air configured for touching and cooling the bell shape B formed in the pipe T.

Preferably, as illustrated in Figures 3 to 6, the belling machine 1 comprises a station 9 for inserting the seal G.

Said insertion station 9 is configured for introducing the seal G inside the end T1 or T2 with the bell shape B just processed by the forming station 5. Preferably, the seal G is made of rubbery material with a high friction coefficient.

Preferably, as illustrated in Figures 3 to 6, the belling machine 1 comprises a station for controlling the quality of the bell shape B of the pipe.

Said station for controlling the quality of the bell shape B identifies the conformity of the bell shape B, if necessary complete with seal G, with established functional and aesthetic requirements.

Again as illustrated in Figures 3 to 6, the belling machine 1 comprises a station 6 for unloading the pipes T with the bell shape B.

In this unloading station 6, the pipes T with a bell shape forming part of the multi-belling group are released, at least one at a time, in such a way as to abandon the translation plane 3.

The unloading station 6 is positioned laterally along the second direction D2 to the forming station 5, or, if necessary, to the station 9 for inserting the seal G when provided, or, if necessary, to the station for controlling the quality of the bell when provided.

The belling machine 1 also comprises a zone Z2 for collecting the pipes T. Preferably, in the collection zone Z2 there are pipes T of the single joint type.

The unloading station 6 is operatively associated with the zone Z2 for collecting the pipes T. More specifically, the unloading station 6 is configured at least to release, at least one at a time, the pipes T from the translation plane 3 to the collection zone Z2.

Preferably, the unloading station 6 comprises a motor-driven belt 62 in communication with the collection zone Z2.

Again preferably, the unloading station 6 comprises a first substation with movable partitions 61. The aim of the movable partition substation 61 is to regulate the release of the pipes T towards the motor-driven belt 62.

The motor-driven belt 62 is configured for transporting to the collection zone Z2 the pipes T released from the substation with movable partitions 61.

Advantageously, the motor-driven belt 62 is equipped with a side panel movable between a first active configuration, for retaining the pipe T inside the motor-driven belt 62, and a second passive configuration, for the outfeed of the pipe T from the belt.

Preferably, the collection zone Z2 is also equipped with a second substation with partitions for receiving and keeping separate the pipes T which have exited and positioned by the motor-driven belt 62.

According to another aspect, the belling machine 1 comprises an outfeed zone Z4 for the pipes T, with a single bell or double jointed, from the belling machine.

More specifically, the unloading station 6 is operatively associated with the outfeed zone Z4 of the pipes T from the belling machine 1.

Preferably, at the outfeed zone Z4 there is a packaging of the pipes T processed by the belling machine 1.

In other words, the pipes T, with a single bell or double jointed, present in the outfeed zone Z4 are preferably intended for packaging, for example in boxes or on pallets.

According to one aspect of this invention, the unloading station 6 comprises a sorting device 63.

In this embodiment, the unloading station 6 comprises a plurality of paths 64, 65, associated with the sorting device 63.

According to one aspect of this invention, the belling machine 1 comprises a sorting device 63.

A plurality of paths 64, 65 extend starting from the sorting device 63.

More specifically, the sorting device 63 is configured for selectively directing the pipes T, exited, at least one at a time, from the translation plane 3 towards one of the paths of the plurality of paths 64, 65.

The plurality of paths 64, 65 comprises at least a first path 64 and a second path 65.

The first path 64 and the second path 65 differ for at least part of their length.

In particular, the second path 65 is located, for at least part of its length, at a height different from the height of the first path 64.

Preferably, as illustrated in Figure 8, the second path 65 is located at a height lower than the first path 64.

According to one aspect, at least the first path 64 of the plurality of paths is associated with the collection zone Z2.

According to another aspect, at least the second path 65 of the plurality of paths is associated with the outfeed zone Z4.

Advantageously, the presence of the sorting device 63 makes it possible to control in an optimum manner mixed production of pipes T.

The term mixed production of pipes means both mixed production of single bell pipes and double jointed pipes, or the production of pipes of different lengths.

The possibility of differentiating the path of the pipes T on the basis of desired rules makes it possible to provide a machine which is extremely flexible in use and fast in the sorting process of the pipes T released such as not to penalise the speed of the belling process.

This invention illustrates an example wherein the sorting device 63 differentiates the path of the double jointed pipes from the path of the single joint pipes, that is to say, the semi-finished pipes having one end shaped in the form of a bell and the other end not yet bell-shaped but designed to be so.

According to an embodiment, illustrated in particular in Figure 8, the sorting device 63 comprises a movable hatch 66.

The movable hatch 66 is, preferably, hinged to a frame of the sorting device 63.

The movable hatch 66 is movable in a plurality of positions (at least a part of said positions being associated with the paths 64, 65) and can be selectively associated with a path of said plurality of paths 64, 65. According to this embodiment, the sorting device 63 comprises an actuator 67, operatively associated with the hatch 66 for moving it and for associating it with a path of said plurality of paths 64, 65.

In the embodiment of Figure 8, the hatch 66 can be associated with two paths, the first path 64 and the second path 65.

The actuator 67 moves the hatch between a first raised position (shown in Figure 8) for associating with the first path 64 and a second lowered position for association with the second path 65.

The first path 64 and the second path 65 are located at two heights different from the ground.

Again preferably, at least for part of their length, the first path 64 and the second path 65 are parallel to each other and spaced in height from the ground.

Still more preferably, as illustrated in the embodiment of Figure 8, the first path 64 is associated with the collection zone Z2 and is raised with respect to the path 65, in turn associated with the outfeed zone Z4.

At the first path 64 there is the motor-driven belt 62 equipped with a movable side panel, for transporting the pipes, released by the sorting device 63, to the collection zone Z2, and, if necessary, a second substation with partitions for positioning the pipes in the collection zone Z2.

The second path 65 is, on the other hand, associated with the outfeed zone Z4.

Preferably, as shown in the embodiment illustrated, along the path 65 there is a lifting device 68 configured to move the pipes T to the outfeed zone Z4. The times for switching the position of the hatch 66 by the actuator 67 must be, preferably, less than the times for releasing the pipes T from the translation plane 3, so as to be advantageously able to sort each pipe T independently and optimally.

Preferably, the plurality of paths 64, 65 comprises a path for the pipes T having a bell shape B recognised as not in compliance by the station for controlling the quality of the bell shape B of the pipe.

Advantageously, the path excludes the pipes T which do not conform from any packaging or belling processes of the opposite end.

According to another aspect of this invention, the belling machine 1 comprises a movement device 7.

Said movement device 7 is configured, in particular, for moving each group of pipes T along the translation plane 3.

Specifically, the movement device 7 is configured to move, along the translation plane 3, each group of pipes T from the forming station 2 of groups of pipes T to the unloading station 6, passing through the at least one heating station 4 and the forming station 5.

In this way, the movement device 7 defines a main path P1 for feeding the pipes T along the translation plane 3.

The forming station 2, the at least one heating station 4, the forming station 5 and the unloading station 6 are, therefore, facing the translation plane and positioned parallel to the main feed path P1 of the pipes T. Preferably, the path P1 is parallel to the second direction D2 and at right angles to the first direction D1.

According to one embodiment, the movement device 7 comprises a plurality of transfer elements 71, 72, 73, 74, 75 located at the above- mentioned forming stations 2, at least one heating station 4, forming station 5 and unloading station 6.

Said transfer elements 71 , 72, 73, 74, 75 are configured for transferring the pipes T between the above-mentioned stations along the main path P1. Said transfer elements 71 , 72, 73, 74, 75 are also configured for positioning each group of pipes T at the above-mentioned stations, to advantageously guarantee an optimum processing.

In this embodiment, the transfer elements 71 , 72, 73, 74, 75 take up the pipes T sequentially. Each transfer element is, therefore, responsible for transferring the pipes to one of the above-mentioned stations and the optimum positioning of the pipes T at said station.

More specifically, each of the transfer elements 71 , 72, 73, 74, 75 has at least one gripping element, designed to come into contact with the pipes T at the top.

Preferably, each gripping element has a concave shape for coupling at least partly with the outer profile of the pipes T.

Advantageously, each of the transfer elements 71 , 72, 73, 74, 75 has a plurality of gripping elements for simultaneously transferring several pipes T between the above-mentioned stations and, therefore, to allow multi- belling or simultaneous belling of several pipes to be performed.

In the embodiment illustrated in the accompanying drawings, each of the transfer elements 71 , 72, 73, 74, 75 has four gripping elements, designed to define a four-position rack, so as to simultaneously transfer four pipes T between the processing stations.

Advantageously, this increases the productivity of the belling machine by a multiplication factor equal to four.

According to another aspect of this invention, the belling machine 1 comprises a manipulating device 8. The belling machine 1 also comprises a zone Z3 for releasing the pipes T. According to one aspect, the release zone Z3 comprises single joint pipes, that is to say, semi-finished pipes having a single end shaped in the form of a bell and the other end still unfinished and generally not bevelled.

The handling device 8 is configured for picking up at least one pipe T from the collection zone Z2, for roto-translating the at least one pipe T up to a release zone Z3 and releasing the at least one pipe T in said release zone Z3.

In the embodiment shown in the accompanying drawings, the handling device 8 is configured to perform a rotation 180° of the at least one pipe T in a plane containing the longitudinal axis of the pipe during the transfer from the collection zone Z2 to the release zone Z3.

Preferably, the handling device 8 is configured to perform a rotation 180° of the at least one pipe T in a plane parallel to a supporting surface of the belling machine 1.

Preferably, the handling device 8 is configured to perform a rotation 180° of the at least one pipe T in a plane parallel to the translation plane 3.

The accompanying drawings, and in particular Figure 6, illustrate an intermediate moment of the roto-translation, wherein the at least one pipe T has already been rotated by 180°, but has not yet been deposited in the release zone Z3.

More specifically, the manipulating device 8 comprises at least one retaining element 81 for retaining the at least one pipe T during the roto- translation of the handling device 8 up to the release zone Z3.

Each retaining element 81 is configured for holding a pipe T.

According to an embodiment, the retaining element 81 comprises a gripper for gripping and retaining the pipe T.

Preferably, the manipulating device 8 comprises a plurality of retaining elements 81, in such a way as to advantageously perform the picking up, the roto-translation and the release of a plurality of pipes T simultaneously. In the embodiment illustrated in the accompanying drawings, the handling device 8 comprises four retaining elements 81 , so as to pick up, roto- translate and simultaneously release four pipes T. Advantageously, in this way the productivity of the handling device 8 is increased by a multiplication factor equal to four.

According to one embodiment, the handling device 8 comprises at least one actuator 82, operatively associated with the at least one retaining element 81.

Said actuator 82 is configured to rotate the retaining elements 81 by 180° during the roto-translation of the handling device 8, as illustrated for example in Figure 4 and Figure 8.

According to the embodiment of the accompanying drawings, the belling machine 1 comprises a frame 83.

The frame 83 is designed to guide the movement of the handling device 8. As illustrated in particular in Figures 3 and 4, the handling device 8 is movable, preferably constrained to the frame 83, along a third direction D3 parallel to the second direction D2.

According to an embodiment, the handling device 8 is movable, again constrained by the frame 83, also along directions parallel to a fourth axis D4, at right angles to the first direction D1 and to the second direction D2. In the embodiment illustrated in particular in Figure 3, the motor-driven belt 62 conveys the pipes T unloaded, one at a time, from the translation plane 3 from a position along the second direction D2 to the collection zone Z2, preferably with a trajectory perpendicular to the second direction D2.

Said collection zone Z2 is preferably located along the third axis D3.

From the collection zone Z2, the pipes T are picked up by the handling device 8, transported to the release zone Z3 and simultaneously rotated by 180°.

After reaching close to the release zone Z3, the handling device 8 releases the roto-translated pipes T into the release zone Z3.

Said release zone Z3 is in communication with the infeed zone Z1 of the pipes T.

Preferably, a second motor-driven belt 32 is operatively associated with the release zone Z3. Preferably, the release zone Z3 is equipped with a third substation with movable partitions for receiving the pipes T handled and transported by the handling device 8.

Preferably, the second motor-driven belt 32 has a longitudinal extension parallel to the first direction D1.

Said third substation with movable partitions is configured, preferably, for regulating the release, one at a time, of the pipes T deposited on the second motor-driven belt 32.

The pipe, positioned on the second motor-driven belt 32, is transferred from the release zone Z3 to a transfer device 31.

The transfer device 31 is configured for transferring the pipe T, released from the release zone Z3, from the second motor-driven belt 32 to the first motor-driven belt 22, through which it reaches the infeed zone Z1. Preferably, the first motor-driven belt 22 and the second motor-driven belt 32 transport the pipe T along a direction parallel to the first direction D1. Again preferably, the transfer device 31 transfers the pipe T from the motor-driven belt 22 to the second motor-driven belt 32 along a direction parallel to the second direction D2.

According to one aspect of this invention, therefore, the first motor-driven belt 22, the transfer device 31 and the second belt 32 are configured to coordinate the arrival of the pipes T in the infeed zone Z1 from the release zone Z3, as well as from the feed line X.

Advantageously, thanks to the joint action of the handling device 8, of the motor-driven belts 22, 32 and of the transfer device 31 , it is possible to move to the infeed zone Z1 the single joint pipes, that is to say, the semi finished pipes having one end shaped in the form of a bell and the other end not yet bell-shaped but designed to be so.

In this way, the single joint pipes can be processed by the stations of the belling machine 1 at the end which has not undergone the belling operation at the first passage of the pipe T, after its entry into the belling machine 1 from the feed line X. The belling machine according to the invention therefore makes it possible to make plants for the automated production of double jointed pipes, without the provision of several belling machines in the plant, keeping the overall dimensions of the plant compact and without penalising the production capacity of the belling machine.

Moreover, the costs due to the purchase, maintenance and management of a second belling machine are avoided.

The belling machine according to the invention achieves the above- mentioned aims, that is to say, those of providing an automatic belling machine for pipes made of thermoplastic material which is particularly versatile, with considerably reduced costs and overall dimensions compared with the prior art belling solutions.

This invention also relates to a method 100 for belling pipes T made of thermoplastic material, illustrated schematically in Figure 7 and relative to some steps also in Figure 8.

The belling method 100 comprises a picking up step 101.

Said picking up step 101 comprises the picking up from an infeed zone Z1 at least one pipe T having at least one of the ends T1 , T2 which is not bell shaped B.

The definition of pipes T having at least the end T1 , T2 not having a bell shape B comprises both the pipes T extruded by the feed line X, therefore without having any end with a bell shape B, and single joint pipes, that is to say, semi-finished pipes having one end shaped in the form of a bell and the other end not yet bell-shaped but designed to be so.

Preferably, during this picking up step 101, the pipes T are picked up from the infeed zone Z1.

According to another aspect, the belling method 100 comprises a step of forming groups of pipes T, at a station 2 for forming groups of pipes.

The step of forming groups of pipes T comprises positioning the pipes T on a translation plane 3, according to an arrangement organised in groups of several pipes T, so that the following steps of the method are performed on several pipes simultaneously with obvious advantages in terms of efficiency of the belling method 100.

Preferably, the step of forming groups of pipes T comprises positioning the pipes T on the translation plane 3 alongside and parallel to each other.

The following steps of the belling method 100 are to be understood as being able to be performed on pipes T individually or which can be performed on groups of pipes T simultaneously.

As illustrated in Figure 7, the belling method 100 comprises a step 102 of heating said pipes T at one of the ends T1 , T2.

During the heating step 102 the end T1 , T2 affected by the heating process is brought from the solid state to the softened plastic state, preferably, by using heating elements such as, for example, ovens, at least at one heating station 4.

Advantageously, the passage to the softened plastic state makes it easier to perform the subsequent deformation operations steps provided under the subsequent steps of the belling method 100, which will be described below.

Preferably, due to the long heating times necessary for the pipe T to pass from the solid state to the softened state, the heating step 102 comprises at least two heating sub-steps.

Advantageously, this splitting of the heating step 102 allows several partial heating actions to be performed in parallel and thus avoiding lengthy waiting times due to the times of a single heating step.

The splitting of the heating step 102 brings obvious advantages in terms of efficiency of the belling method 100 in its entirety.

According to one aspect of this invention, the belling method 100 comprises a forming and cooling step 103 in a forming station 5.

More specifically, during the forming and cooling step 103, for creating the bell shape B at the heated end T1 or T2 in the heating step 102.

This forming and cooling step 103 preferably comprises the use of moulds for generating the bell shape B at the end T1 , T2 of said pipe T, previously brought to the softened state in the heating step 102.

The same forming and cooling step 103 comprises, again preferably, the use of aeration systems for generating a jet of air designed to touch and cool the pipe T.

As illustrated in Figure 7, the belling method 100 comprises a step 104 of unloading the pipes T, at an unloading station 6.

Simultaneously with the above-mentioned steps, the belling method 100 comprises a step of feeding each group of pipes T from the forming station 2 of groups of pipes T to the unloading station 6, through the heating station 4 and the forming station 5, defining a main path P1 for feeding the pipes T.

According to one aspect, the unloading step 104 comprises unloading the pipes T, one at a time, towards at least one collection zone Z2.

In other words, as illustrated in Figure 9, in the unloading step 104, at least part of the pipes T formed in the forming and cooling step 103 are directed to the collection zone Z2.

According to another aspect, as illustrated in Figure 9, the unloading step 104 comprises unloading the pipes T, one at a time, towards at least one outfeed zone Z4.

In other words, in the unloading step 104, at least part of the pipes T formed in the forming and cooling step 103 are directed to an outfeed zone Z4.

Preferably, the outfeed zone Z4 represents a stationary zone for the pipes T, with a single bell or double bell, waiting to be packed.

As illustrated in Figure 9, according to an aspect of the invention the unloading step 104 comprises a sub-step 104' for sorting the pipes T. According to one aspect, the sorting sub-step 104' comprises the sorting, that is, selective directing, of the pipes T at least towards the collection zone Z2.

According to another aspect, the sorting sub-step 104' comprises the sorting, that is, the selective directing, of the pipes T at least towards the outfeed zone Z4.

More specifically, the sorting sub-step 104' comprises selective directing of the pipes T along a plurality of paths 64, 65.

The sorting sub-step 104' preferably comprises moving a sorting device 63, which can be selectively associated with the plurality of paths 64, 65.

At least a first path 64 of said plurality of paths 64, 65 is connected to the collection zone Z2.

At least a second path 65 of said plurality of paths 64, 65 is connected to the outfeed zone Z4. According to an embodiment, the sorting device 63 comprises a movable hatch 66.

According to this embodiment, the sorting device 63 comprises an actuator 67, operatively associated with the hatch 66 for moving it and for associating it with a path of said plurality of paths 64, 65. In this embodiment, the sorting sub-step 104' comprises controlling said actuator 67 and the consequent movement of the hatch 66.

Figure 9 illustrates, by means of a sequence of successive steps, an example of the operation of the sorting device 63, in an embodiment comprising the hatch 66 and the actuator 67. A transfer element 75 is configured for retaining and moving the pipes T which remain stationary on the plane of translation 3 close to the hatch 66. Preferably, the translation plane 3 terminates at the hatch 66, as illustrated in Figure 9.

The transfer element 75 is configured to perform sequential movements of length P, that is to say, by a length equal to the centre-to-centre between two pipes T retained by the gripping elements of the transfer element.

Each movement of the length P causes the escape from the translation plane 3 of one pipe P at a time and the consequent detachment of the pipe from the gripping element, which touches the pipe only above. In the embodiment of Figure 9, the white pipes (that is, the central pipes held by the retaining element 75 of Figure 9a) are sorted from the hatch 66 towards a first path 64.

Vice versa, the black pipes (that is, the outer pipes held by the retaining element 75 of Figure 9a) are sorted from the hatch 66 towards a second path 65, located at a height lower than the first path 64. In Figure 9b, the hatch 66 is in the lowered configuration and keeps the second path 65 open.

The pipe released by the first movement of length P of the retaining element 75 is sorted, substantially by gravity, towards the second path 65. In Figure 9c, the hatch 66 is moved by the actuator 67 and is in the raised configuration, closing the second path 65 and keeping accessible only the first path 64.

The second pipe, released by the second movement of length P of the retaining element 75, is sorted, substantially by gravity, towards the first path 64, as illustrated in Figure 9d. The pipe T travels through the hatch 66 and reaches a substation with movable partitions 61 , as illustrated in Figure 9e. The aim of the substation with movable partitions 61 is to regulate the release of the pipes T towards a motor-driven bet 62 for directing the pipes to a collection zone Z2.

Figure 9f shows the release of the third pipe following the third movement of the retaining element 75 and the simultaneous release of the second pipe T from the substation with movable partitions 61 to the motor-driven belt 62.

The third pipe is also sorted towards the first path 64 until reaching the substation with movable partitions 61 , as shown in Figure 9g which also illustrates the lowering of the hatch 66.

A further movement of a length P results in the detachment of the last pipe, which is directed towards the second path.

Figure 9i illustrates the return movement of the retaining element 75 to the starting position and the lifting of the hatch 66. In the starting position the device is ready to receive a new group of pipes T, as illustrated in Figure 9I. Advantageously, the release of one pipe T at a time allows an optimum and customised sorting for each pipe arriving at the sorting device. According to another aspect, the belling method 100 comprises a collection step 105.

In the collection step 105, the pipes T which have been directed to the collection zone Z2 are picked up in the unloading step 104.

Preferably, as illustrated in Figure 8, the collection step 105 comprises lifting the pipes T from the collection zone Z2.

The belling method 100 comprises a roto-translation step 106.

During the roto-translation step 106, the pipes T collected by the collection zone Z2 are transported from the collection zone Z2 towards a release zone Z3 and are simultaneously rotated in a plane containing the longitudinal axis of the pipes T.

Preferably, the pipes T are rotated on a plane parallel to a supporting surface of the machine which actuates the belling method 100.

Preferably, the roto-translation step 106 comprises a rotation by 180° of the pipes T collected by the collection zone Z2, as illustrated in Figure 8. The belling method 100 also comprises a step 107 of releasing the roto- translated pipes T in the release zone Z3.

Preferably, the release step 107 comprises a lowering of the pipes T until reaching the release zone Z3, as illustrated in Figure 8.

Preferably, the collection step 105, the roto-translation step 106 and the release step 107 are performed by means of a handling device 8.

Again as illustrated in Figure 7, the belling method 100 comprises a step of conveying 108 from the release zone Z3 to the infeed zone Z1 of the pipes released in the release zone.

More specifically, the pipes T transported from the release zone Z3 to the infeed zone Z1 are added, in the infeed zone Z1 , to the pipes T coming from the feed line X (to then be subjected to belling at an end without this bell shape).

In this way, in the infeed zone Z1 it is possible to direct, without interference, the pipes unprocessed at both ends, coming from the feed line X, and semi-finished single joint pipes, that is to say, pipes T which have only one bell-shaped end and which during the unloading step 104 have been directed towards the collection zone Z2. Thanks to the presence of the steps for collection 105, roto-translation 106, releasing 107 and transport 108 it is advantageously possible to manage the production of double jointed pipes using a single machine, providing an infeed zone Z1 which is able to receive both unprocessed pipes and semi-finished pipes. Moreover, the belling method 100 advantageously allows a belling method to be achieved which is able to control in an optimum manner mixed production of pipes T.

The term mixed production of pipes means both mixed production of single bell pipes and double jointed pipes, or the production of pipes of different lengths.

The presence of the sorting sub-step 104' makes it possible to differentiate the path of the pipes T on the basis of desired rules and to provide an extremely flexible method for its execution.

The method 100 for belling pipes made of thermoplastic material is thus particularly efficient and achieves the preset aims.