Patent Description:
The present invention relates to an apparatus for manufacturing a head of a module of a radiator from two half-heads, and a corresponding manufacturing method.

In particular, the present invention is advantageously but not exclusively applied to the production of tubular multi-column steel radiators, to which the following description will explicitly refer without thereby losing generality.

As is known, a tubular multi-column steel radiator is a radiator comprising a plurality of modules, also more simply known as elements, each of which comprises a plurality of columns, i.e. a plurality of tubular elements, closed by two heads. In particular, each module is manufactured by joining by welding, for example resistance welding, the first ends of a certain number of columns to a first head and the second ends of the columns to a second head. Each head is a hollow body comprising a plurality of sleeves which are welded to the ends of relative columns and a circular through opening to allow mounting between adjacent modules.

Each head is normally manufactured by producing, first, by moulding, two half-heads, i.e. two half-shells having the shape of a head cut along a longitudinal symmetry plane, having respective edges to be joined, then smoothing and chamfering the edges and, finally, joining the two half-heads together by laser welding the smoothed and chamfered edges while the latter are in mutual contact. Therefore, each half-head has a respective circular opening which is coaxial with the circular opening of the other half-head to define the circular through opening of the head.

In particular, the joining of the two half-heads provides for clamping the two half-heads against each other with the respective edges in mutual contact and welding the two half-heads together along the two edges in mutual contact with each other by means of carbon dioxide laser welding, i.e. more simply CO<NUM> laser, while the two half-heads are clamped.

More in detail, an apparatus for manufacturing heads of a module of a radiator comprises a clamping system for clamping the two half-heads in contact with each other and a CO<NUM> laser welding system for welding the two half-heads together along the two edges in mutual contact with each other.

The clamping system comprises a pair of jaws which are connected to each other through the circular openings of the half-heads and are closed as a plier against surface portions of the half-heads. The clamping system must keep the half-heads clamped maintaining the respective edges perfectly aligned with each other during the entire welding step so that at the end of such step the head is not deformed or defective in proximity to the welding line.

The CO<NUM> laser welding system comprises a CO<NUM> laser head and handling means for moving the CO<NUM> laser head around the half-heads while they are clamped against each other so as to weld the two edges together in mutual contact with each other. The laser beam emitted by a CO<NUM> source typically has a rather open cone. To obtain greater precision during the welding, the CO<NUM> laser head comprises a focusing mirror and a cooling system for cooling the focusing mirror. For this reason, a CO<NUM> laser head has relatively large dimensions and a relatively high energy consumption.

Due to the large dimensions, the CO<NUM> laser head requires plenty of room for manoeuvre around the half-heads while they are clamped by the pair of jaws, in order to be able to accurately weld the entire contact line between the edges of the half heads. In order not to interfere with the movement of the CO<NUM> laser head, the pair of jaws clamping the half-heads must have reduced dimensions. This entails having jaws that do not press uniformly on the entire surface of the half-heads. Consequently, the heat produced by the welding in combination with a non-uniform pressure of the pair of jaws often causes deformations in the manufactured head.

European Patent No. <CIT> (forming the basis for the preamble of the independent claims) discloses a method for manufacturing heads of pressed metal plate radiator elements in which each head is formed by two complementary half-shells to be joined at their respective edges. According to the method, the half-shells are first shaped so that at least one of them has a plurality of tooth-like raised portions on its joining edge, then the half-shells are arranged so that they are mated at the edges, welded with a capacitor discharge to achieve a joint only at the raised portions, and finally welded in the remaining parts of the edges by braze welding.

European Patent No. <CIT> discloses a method for manufacturing a tubular radiator of the type comprising a plurality of adjacent radiating elements each comprising a tube having, at each of the ends thereof, a head consisting of two half shells. According to the method, the two half shells are coupled by laser welding with forming of burr at least on the outside at the external contact edge thereof, so as to ensure a hydraulically and mechanically sealed coupling, and each head is coupled to the tube by capacitor discharge welding by exerting a contact pressure suitable for the interpenetration between the materials of each head and of the tube with forming of inside and outside burr at the coupling edge so as to ensure a hydraulically and mechanically sealed coupling.

Japanese Patent Application No.<CIT>discloses a method for manufacturing a radiator panel by placing two sheets of formed metallic sheets between a male die and a female die, and subjecting the end faces to welding of deep throat depth by laser welding. The radiator panel obtained through the method prevents corrosion from end faces and has increased mechanical strength.

German Patent No. <CIT> discloses a device for welding half shells of container. The welding device has first and second controlled movable holders for each half shell, having first and second clamping jaw, respectively. The jaws compress the peripheral flanges of the half shell. The welding device has a number of clamping devices for controllable connection of both clamping jaws.

<CIT> discloses a laser welding apparatus for welding flat panels together by using clamping jig.

The object of the present invention is to provide an apparatus for manufacturing a head of a module of a multi-column steel radiator, which is free from the drawbacks described above and, at the same time, is easy and costeffective to manufacture.

In accordance with the present invention, an apparatus and a method for manufacturing a head of a module of a radiator are provided as defined in the appended claims.

In order to better understand the present invention, a preferred embodiment will now be described, by way of a mere non-limiting example and with reference to the accompanying drawings, wherein:.

In <FIG>, reference numeral <NUM> generally indicates, as a whole, one of the two heads of a module of a tubular multi-column radiator, preferably made of steel.

The head <NUM> is illustrated in <FIG> still divided into two half-heads <NUM> symmetrical with respect to the longitudinal geometric plane and having respective edges <NUM> defined along respective longitudinal planes, and in particular smoothed and chamfered in a known manner and with known techniques, for being joined together so as to form the head <NUM>. In general, in fact, a method for manufacturing the head <NUM> provides for producing two half-heads <NUM>, for example by moulding, smoothing and chamfering the edges <NUM>, clamping the two half-heads <NUM> in contact against each other at the respective edges <NUM> and welding the two half-heads <NUM> at the edges <NUM> in mutual contact with each other, for example using a laser.

<FIG> illustrates the head <NUM> after the joining of the half-heads <NUM> and the welding thereof along a contact line <NUM> defined by the edges <NUM> in mutual contact. The head <NUM> has a plurality of sleeves <NUM>, which will then be joined to relative tubular elements (not illustrated) for forming a module of the multi-column radiator.

With reference to both <FIG>, each half-head <NUM> has a respective circular opening <NUM> which is coaxial to the circular opening <NUM> of the other half-head <NUM> according to an axis 6a perpendicular to a geometric plane on which the edges <NUM> lie in contact, and therefore the contact line <NUM>, for allowing the assembly of several modules in a row so as to form the radiator.

In <FIG>, reference numeral <NUM> generically indicates as a whole an apparatus for manufacturing the head <NUM> from two half-heads <NUM>.

The apparatus <NUM> comprises a clamping system <NUM> for clamping the two half-heads <NUM> in contact against each other at the respective edges <NUM>, and a laser welding system <NUM> for welding the two half-heads <NUM> together along the two edges <NUM> in mutual contact with each other.

The clamping system <NUM> comprising a pair of jaws <NUM> made up of a mould and counter-mould shaped like the two half-heads <NUM> and a handling system <NUM> for closing the two jaws <NUM> as a plier so that, in use, the latter press uniformly on the two half-heads <NUM>. <FIG> illustrates the handling system <NUM> in the open position of the jaws <NUM> for allowing the two half-heads <NUM> to be positioned on top of each other. <FIG> illustrates the handling system <NUM> in the closed position of the jaws <NUM> for allowing the clamping of the two half-heads <NUM>.

The depth of the shaping of the two jaws <NUM> is of such extent that, when the latter are closed around the half-heads <NUM>, a peripheral slot <NUM> (<FIG>) remains between the jaws <NUM> leaving visible the mutually-contacting edges <NUM> which define the aforementioned contact line <NUM>.

The handling system <NUM> is a motorized mould guiding system.

In particular, the handling system <NUM> comprises a pair of supports <NUM> and <NUM>, each of which supports a respective jaw <NUM>, and at least a pair of movable columns <NUM> for supporting and moving the support <NUM> to and from the other support <NUM>. In the example of <FIG>, the support <NUM> is the lower one and is fixed with respect to a base (not illustrated) of the apparatus <NUM> and the support <NUM> is the upper one and is movable. A first jaw <NUM> is fixed on top of the support <NUM> and the other jaw <NUM> is fixed under the support <NUM> so that the jaws <NUM> are interposed between the supports <NUM> and <NUM> and the movement of the support <NUM> towards the support <NUM> closes the jaws <NUM> as a plier. The support <NUM> has two through holes (not visible) and is provided with two respective circular guides <NUM> coaxial to such through holes, each hole and the respective coaxial guide <NUM> being slidingly crossed by a relative column <NUM>.

The handling system <NUM> comprises a pair of linear actuators <NUM> for translating, each one, a respective column <NUM> along its own axis 15a. In the illustrated example embodiment, the axis 15a is vertical. The actuators <NUM> work in traction to close the jaws <NUM> and in thrust to open the jaws <NUM>. The actuators <NUM>, when working in traction, exert a force for exerting the necessary pressure on the half-heads <NUM> during the welding so as to clamp the half-heads <NUM> but without deforming them due to the heat produced by the welding. The actuators <NUM> are, for example, of electric, hydraulic or pneumatic type.

The laser welding system <NUM> comprises a known type of fiber laser head <NUM> and a handling device (not illustrated) for moving the fiber laser head <NUM> around the pair of jaws <NUM> closed as a plier, along the slot <NUM>, so as to direct a laser beam along the two mutually-contacting edges <NUM> and cover the entire contact line <NUM>.

According to a first embodiment not illustrated, the handling device comprises a kinematic mechanism specially designed to support and guide the fiber laser head <NUM> along a geometric plane on which the contact line <NUM> lies.

According to a further embodiment not illustrated, the handling device comprises an anthropomorphic or Cartesian robotic device designed to support and move the fiber laser head <NUM> so as to move the laser beam along the contact line <NUM>.

The fiber laser head <NUM> produces a laser beam having a greatly tapered conic shape and a very much reduced diameter at the focusing point. Such features allow the laser beam to pass through the slot <NUM> without touching the jaws <NUM> and to weld with precision along the contact line <NUM> also between the sleeves <NUM> of the head <NUM>.

The fiber laser head <NUM> comprises an optical output <NUM> for emitting the laser beam according to an emission direction 19a. Advantageously, the optical output <NUM> is motorized to rotate about an axis parallel to the emission direction 19a with the aim to optimize the welding process, should the laser beam have a diameter which is too reduced.

According to a further embodiment illustrated in <FIG>, wherein the corresponding elements are indicated with the same reference numerals and abbreviations of <FIG>, the handling system <NUM> comprises, instead of the supports <NUM> and <NUM>, two analogous supports <NUM> and <NUM> for supporting the two jaws <NUM>, and, instead of the columns <NUM> and the actuators <NUM>, a pair of hinges <NUM> for connecting the two supports <NUM> and <NUM> along two respective edges so as to be able to rotate the support <NUM> to and from the other support <NUM>, and an actuator <NUM> for carrying out the rotation of the support <NUM>. In the example of <FIG>, the support <NUM> is the lower one and is fixed with respect to a base (not illustrated) of the apparatus <NUM> and the support <NUM> is the upper one and is in fact movable by means of the hinges <NUM>. The rotation axis 22a of the hinges <NUM> is horizontal. Similar to the embodiment of <FIG>, a first jaw <NUM> is fixed on top of the support <NUM> and the other jaw <NUM> is fixed under the support <NUM> so that the jaws <NUM> are interposed between the supports <NUM> and <NUM> and the movement of the support <NUM> towards the support <NUM> closes the jaws <NUM> as a plier.

<FIG> illustrates the handling system <NUM> in the open position of the jaws <NUM> to allow the two half-heads <NUM> to be positioned on top of each other. <FIG> illustrates the handling system <NUM> in the closed position of the jaws <NUM> to allow the clamping of the two half-heads <NUM>. The closing of the jaws <NUM> takes place by virtue of the rotation of the support <NUM> about the rotation axis 22a until it closes like a book on the support <NUM>.

The actuator <NUM> is a linear actuator and has a first end <NUM> connected by means of a hinge <NUM> to a fixed part (not illustrated) of the apparatus <NUM> and a second translating end <NUM> fixed to the support <NUM> by means of another hinge <NUM>. The rotation axes 25a and 27a of the hinges <NUM> and <NUM> are parallel to the rotation axis 22a. The actuator <NUM> is, for example, of electric, hydraulic or pneumatic type.

The actuator <NUM> works in thrust for closing the jaws <NUM> and in traction for opening the jaws <NUM>. When working in thrust, the actuator exerts a force for exerting the necessary pressure on the half-heads <NUM> during the welding so as to clamp the half-heads <NUM> but without deforming them due to the heat produced by the welding.

Claim 1:
Apparatus for manufacturing a head of a module of a radiator, preferably made of steel, from two half-heads (<NUM>) having respective edges (<NUM>) to be joined, previously smoothened and chamfered, the apparatus (<NUM>) comprising a clamping system (<NUM>) for clamping the two half-heads (<NUM>) in contact with each other at the respective edges (<NUM>), and a welding system (<NUM>) for welding the two half-heads (<NUM>) together along the two edges (<NUM>) in mutual contact with each other; the clamping system (<NUM>) comprising a pair of jaws (<NUM>) made up of a mould and counter-mould shaped like the two half-heads (<NUM>) and closable as a plier in such a way that, in use, they press uniformly on the half-heads (<NUM>) and define a slot (<NUM>) that leaves the edges (<NUM>) visible; the apparatus being characterized in that the welding system (<NUM>) is a laser welding system comprising a fiber laser head (<NUM>) and handling means for moving the fiber laser head (<NUM>) around the pair of jaws (<NUM>) closed as a plier, along said slot (<NUM>) so as to direct a laser beam along the two mutually-contacting edges (<NUM>).