PAINTED ON THEIR SURFACES, PARTICULARLY OF WINDOW FRAMES

AND/OR FURNITURE AND FURNITURE COMPONENTS MADE OF WOOD, AND/OR BY-PRODUCTS, WITH SELECTIVE PICKING UP OF THE PARTS TO BE TREATED AND PAINTED FROM ANY POSITION WHEREIN SUCH PARTS ARE MOVED FROM TIME TO TIME IN THE SAME PLANT

The invention relates to a conveyor plant for a plurality of parts to be treated and painted on their surfaces, particularly of window frames and/or furniture and furniture components made of wood, and/or by-products, with selective picking up of the parts to be treated and painted from any position wherein such parts are moved from time to time in the same plant.

There are known conveyor plants of this kind with horizontal or vertical arrangement, for moving a plurality of parts to be treated and painted on their surfaces, for conveying the parts in sequence toward one or more impregnating stations having impregnating agents of traditional type, then toward one or more painting stations of traditional type, and finally for drying the treated parts and for picking up them from the plant and for packaging them for the delivery to the customers.

Normally, these plants are shaped as a closed loop circuit into which there are arranged, supported and conveyed various rectilinear bars in which there are supported in a hung condition the different parts to be treated and painted, which bars are moved by transmission means and motors and control circuits of the traditional type, and which parts may be all realized with the same shape and sizes, and require paintings with the same colours, or such parts may be realized in part with the above-described same shapes and sizes and in part also with different shapes and sizes, and may be painted both with identical colours and with different colours, by requiring in such case long-time and expensive operations, involving at first the colouring of all parts with the same colour, and then the washing of the painting station from the first used colour and finally the replacement of this colour with the different colour to be applied on to all the parts to be coloured with this additional colour.

These types of plants result not much flexible, since the conveyors with the support bars of the parts are always actuated in a single advancement direction, so that if the parts to be treated and painted in a determined phase of the cycle should be positioned, in the advancement direction of the conveyors, downstream the different parts of which there is not yet required the treatment, it would be anyway necessary to let to pass at first such parts to not be treated through the plant treatment stations, up to position the parts to be treated in correspondence of the treatment stations, thereby allowing the treatment of these parts only, and at the end of this treatment the conveyor should be moved again up to the unloading station of the same parts from the plant. Therefore, one can understand how the operation of the conveyor plants of this kind sometimes involve the unwanted

displacement also of the parts of which it is not yet required the treatment, before to submit the parts to be treated to the required operative phases, and this circumstance involves at the one hand a plant working time that is longer than the one actually needed, and an additional consumption of electric energy for determining this displacement, and at the other hand it determines an operation of the various plant component parts for durations longer than the needed ones, that may require more frequent maintenance interventions on the plant and reduce the life of the same, and that inevitably involve economic losses for the operation and the management of the same plant.

The object of the present invention is to eliminate the above-mentioned disadvantages of the current conveyor plants of the parts to be treated and painted on their surfaces, in such a way to allow to pick up selectively from time to time only the parts to be treated supported by the part carrying bars of the conveyors and placed in any position of the plant, without the need to move as previously also the remaining parts the treatment of which is not required, and, thanks to this selective picking up from time to time of the parts to be treated only, these conveyor plants allow also to colour some parts with one colour and some other parts with one or more different colours, thereby obtaining to treat a greater number of parts for each operative cycle, with a more effective and productive operation of the plant.

The conveyor plant according to the invention allows also to perform more operative phases contemporarily, and to obtain additional important advantages, as it will be described in detail hereinafter.

The invention will be better understood from the following description, given by way of a not-limitative example only, of the constructive characteristics and the operation mode of the present conveyor plant, and with reference to the following accompanying drawings in which :

- Fig. 1 shows a perspective front view of the conveyor plant of the parts to be treated and painted according to the present invention ;

- Fig. 2 shows a plan view of the conveyor plant of Fig. 1 ;

- Fig. 3 shows a perspective front view with a different angle of view and without some component parts of the plant illustrated in Fig. 1 ;

- Fig. 4 shows an enlarged perspective front view of the constructive item A of the Fig. 3 ;

- Fig. 5 shows a perspective back view and with a different angle of view of the plant illustrated in Fig. 1 ;

- Fig. 6 shows an enlarged perspective back view of the constructive item A of the Fig. 5 ; - Fig. 7 shows a schematic front view of the plant of Fig. 2 ; - Fig. 8 shows a front view of a component part of the plant acting as a shuttle for picking up selectively the parts to be treated and painted, that are supported and conveyed from the conveyor plant according to the present invention, wherein such shuttle is displaced in the configuration of displacement of a part carrying bar along the working area of the same shuttle, for bringing it from a working station to another one ;

- Figs. 9 and 10 show a respective plan and side view of the component part of the Fig. 8 ;

- Fig. 11 shows a perspective front and exploded view of the component part of fig. 8 ;

- Fig. 12 shows a front view of the component part of Fig. 8, in which the shuttle is displaced in the working position thereof wherein the parts are grasped by the same shuttle; - Fig. 13 shows a plan view of the component part of Fig. 12 ;

- Fig. 14 shows a plan view of the conveyor plant according to the present invention, that is realized with a different arrangement than that of Fig. 1 and with a determined number of used operative stations, given by way of a not-limitative example only, which operative stations are illustrated for performing the operative phases of a treatment cycle of the parts, such plant being in this case equipped with only one shuttle for picking up selectively of the parts ;

- Fig. 15 shows a plan view of the conveyor plant of the Fig. 14, in which there are provided two shuttles for picking up selectively of the parts ;

- Fig. 16 shows a schematic front view of the conveyor plant of Fig. 15 ;

- Figs. 17 to 33 show respective plan views of the different operative sequences of a treatment cycle of the part in a conveyor plant that is identical to the one of Fig. 14.

In the above figures, it is represented schematically a conveyor plant according to the present invention, realized with limited compacted sizes and provided for conveying a relatively limited quantity of parts to be treated and painted on their surfaces, in particular of window frames and/or furniture and furniture components made of wood, and/or by- products (medium-density, plywood, etc .), and/or materials different than the wood and by-products, with selective picking up of the parts to be treated and painted from any position wherein such parts are placed from time to time in the same plant. The conveyor plant is designed also with specific treatment and painting stations for parts, that will be described in detail hereinafter. The parts to be treated and painted may be shaped with different forms and sizes, provided that they may be contained into the same conveyor plant, and are loaded on to the conveyor that conveys them in sequence through the different treatment stations, where the parts may be coloured with paints of any colour, depending on the client requests, and at the end of the different phases of each operative cycle the treated and painted and dried parts are unloaded from the conveyor plant referred to and packaged for being delivered to the relative clients.

As particularly visible in the Figs. 1-7, the present conveyor plant is constituted substantially by a first and by a second metallic frame 5, 6 of parallelepiped form with horizontal extension, which are aligned and placed side by side in a position parallel and spaced away to each other, by delimiting between them a free sliding path 7 extended in the direction of the depth of the same frames, and provided for housing at least a movable shuttle element 8, slidable in the alternate direction for the whole length of such path and shaped and operating in a manner to provide for the selective picking up of the parts to be treated and painted as it will be described.

In particular, the first metallic frame 5 is formed by a pair of peripheral and longitudinal metallic section-bars 9 and 10, identical and parallel and spaced away to each other in the depth direction of the plant, and by a pair of peripheral and transversal metallic section- bars 1 1 and 12, parallel and spaced away to each other in the longitudinal direction of the plant, and which are joined to the correspondent longitudinal section-bars 9 and 10, thereby defining and upper horizontal flat framework. Such first metallic frame 5 in the described example is also formed by four rectilinear and vertical legs 13, 14, 15 and 16, identical to each other and the upper ends portions of which are fixed in the angular zones of the upper framework, whereas the lower end portions are leant and opportunely anchored to the floor. Finally, this first metallic frame 5 is also formed by two intermediate vertical legs 17 and 18, the upper end portions of which are fixed to the centre line of the relative transversal section-bars 11 and 12 and may be joined to each other also by a possible additional rectilinear horizontal and longitudinal section bar 19, whereas the lower end portions of which are also leant and opportunely anchored to the floor.

Such middle longitudinal section bar 19 acts for reinforcing and stiffening the metallic frame 5, together a set of metallic cables or reinforcing bracings 20 fixed in diagonal among the different vertical legs 13, 14 and 17. In the first metallic frame 5 there are also fixed two rectilinear transversal section bars 21 and 22, which are identical and parallel and spaced away to each other in the longitudinal direction of such first metallic frame 5 and are extended in the transversal direction of this latter, for its entire length, and are fixed with their end portions respectively to the opposite walls of the correspondent front and back longitudinal section bar 9, 10, respectively, and also centrally with the middle longitudinal section bar 19. The left-side transversal section bar 21 is arranged almost in the centre line of the front, back and middle longitudinal section bars 9, 10 and 19, whereas the right-side transversal section bar 22 is arranged near to the right-side peripheral transversal section bar 12.

As it is shown also in the Fig. 7, above the first metallic frame 5 it is fixed for the entire extension thereof a covering structure 23 formed by insulating panels, underneath which there are arranged some rectilinear and suspended metallic guide members 24, that are supported by the section bars 21 and 22 and arranged parallel and slightly spaced away to each other in the transversal direction of the same metallic transversal framework (see Figs. 1 and 2), and along each suspended metallic guide member 24 a relative part carrying bar 25 of lengthened rectilinear shape is slidable in the internal or in the upper side thereof, and in the bars 25 there are hooked and supported the parts 26, by means of hooks 27 or other suitable support means. The parts 26 are supported by the bars 25 in positions spaced away and put side by side to each other, and may have the same dimensions or also dimensions different to each other, as visible in the Fig. 7, and such bars 25 may slide into the relative suspended guide members 24, with the parts supported by the same bars, by means of an horizontal movement effected by means of the movable shuttle element 8, in the manner that will be described.

The right-side end portions of all the rectilinear bars 25 are extended beyond the right-side transversal section bar 12 of the metallic frame 5, in order to allow each bar 25 to be grasped and let to slide in the horizontal direction of the movable shuttle element 8, when this latter is displaced in correspondence of such bar, and particularly each bar 25 may be displaced from its rest position, wherein such bar is completely inserted into the metallic frame 5 (see Figs. 1 and 2), to its working position completely extracted from the metallic frame 5, together with the parts 26 supported by this bar, wherein the bar 25 and the parts 26 are arranged themselves in the free sliding path 7, and vice-versa such bar with the supported parts may be displaced again from above described working position to the rest position thereof, in order to perform the functions that will be described hereinafter.

In this way, into the first metallic frame 25 it is formed a single area for containing the bars 25 and the parts 26, acting both as loading zone on to the different bars 25 of all the parts to be treated and painted on their surfaces, as drying zone of the parts already treated and painted and as unloading zone of the bars 25 with all parts that have been treated and painted on their surfaces, and which are completely dried. The stations for the surface treatment of the parts in the described example are preferably constituted by an

impregnating station 28 and by at least a painting station 29 of traditional type, that are situated in the second metallic frame 6, in the positions that will be next described. The impregnating station 28 may also not be foreseen, if there is not required the application of the impregnating agent of traditional type onto the parts 26, and the sole painting of the same parts be foreseen. Such painting station 29 could also not be foreseen, in the case in which the painting of the parts not be foreseen, and instead it the impregnating station 28 only could be foreseen, in the case in which the impregnating agent of traditional type only should be applied on to the parts.

In the treatment area defined in the metallic frame 5 the parts to be treated and painted on their surfaces may be loaded and unloaded from the front side, from the back side or also from the lateral sides of the metallic frame 5.

Each operative cycle of the plant is programmed in advance, by acting onto the electric controls housed into the plant control panel 30, and connected by means of wirings 31 with the different component parts of both the first metallic frame 5, and the second metallic frame 6 and the movable shuttle element 8, in such a way that each bar 25 with the loaded parts be displaced from the position in which it is placed by the movable shuttle element 8, that is also displaced in correspondence of such bar, thereby for picking up such bar 25 with the parts supported by the same and for displacing the bar 25 with the parts 26 in correspondence of the stations for the surface treatment 28 and 29 and of the drying zone. Advantageously, the bar 25 with the parts 26 is moved by the movable shuttle element 8 before to the impregnating station 28, where such parts are impregnated, then to the drying area (or warehouse) defined in the first metallic frame 5, where the arts are left to dry for few hours, then after their complete drying the parts 26 are moved with the relative bar 25 to the painting station 29, where the parts are painted. So, at the end of the painting the movable shuttle element 8 provides to move the painted parts with the bar 25 to the drying area, delimited by the metallic frame 5, where the bar 25 with the treated and painted parts is left for the needed time for the complete drying of the treated and painted parts. Finally, at the end of the drying of such parts, where latters are manually unloaded from this bar 25 by the operators. These operative phases of the cycle may be effected singularly on the parts. The considered conveyor plant is externally delimited by a peripheral and covering panelling 23 made in insulating material (see Fig. 7), that in the drying area needs to stifle the warm air for determining the drying of the parts, which warm air is directed in this area as it will be soon described, by limiting the dispersion of the hot outward.

In the first metallic frame 5, furthermore, there are installed the systems of suction and direction of the environment air and of heating of the air and of direction of the same through the conveyor plant. As it is shown in Figs. 1 , 2 and 7, the sutcion and direction system for the environment air is of the traditional type, and is constituted by an aspirator 33 mounted onto the upper surface of the metallic frame 5, and communicating both with the underplayed air suction channel 34 and with the air direction and heating channel, formed by a portion of channel 35 also mounted onto the upper part of the metallic frame 5, along the back longitudinal side of this latter, and linked with an additional portion of channel 36 directed downward and in turn linked with an additional portion of channel 37 arranged onto the floor and extended for the entire length of the transversal right side of the metallic frame 5.

Into at least one of above-said portions of channel 35, 36 and 37 there are fixed internally some electrical heating elements 38, connected to the power supply of the present conveyor plant and thermostatic controlled for determining the heating of the air, directed by the aspirator in the A direction of the suction and heating system, to pre-set

temperatures such to allow the drying of the parts into the drying area of the plant. A dehumidifier system, not shown in the above Figures, is also provided The conduit portion 37 arranged onto the floor is provided with a set a through holes 39 turned toward such parts drying area, through which the air sucked and heated by the electric heating elements 38 is directed constantly in the interior of the drying zone for drying the parts at the established temperatures and durations, in a manner that all the treated parts introduced into the drying area zone be completely dried.

In the upper part of the drying zone there are arranged some fans 40 (see Fig. 2), that are actuated in rotation for distributing uniformly the heated air into the drying zone, in a manner to dry uniformly and correctly all the treated parts introduced in the same zone. Referring now to the second metallic frame 6 of the present conveyor plant, it is noted that the same is also formed by another pair of peripheral and longitudinal metallic section bars 41 and 42, having different sizes than the previous longitudinal section bars 9 and 10, and also identical and parallel and spaced away to each other in the plant depth direction, and by another pair of peripheral and transversal metallic section bars 43 and 44, having the same sizes of the previous transversal section bars 11 and 12, and also parallel and spaced away to each other in the plant longitudinal direction, and which are joined to the correspondent longitudinal section bars 41 and 42, thereby defining another flat horizontal upper framework, aligned with respect to the previous upper frame and spaced away therefrom by the free sliding path 7. Also this second metallic frame 6 is formed by four rectilinear and vertical legs 45, 46, 47 and 48, identical to each other and the upper end portions of which are fixed to the angular zones of the upper frame, whereas the lower end portions of which are leant and opportunely anchored to the floor. Finally, also this second metallic frame 6 is formed by two vertical intermediate legs 49 and 50, the upper end portions of which are fixed to the middle line of the relative transversal section bars 43 and 44, whereas the lower end portions of which are also leant and opportunely anchored to the floor. In the right-side vertical legs 47, 48 and 50 there are also fixed some metallic cables or reinforcing and stiffening bracings 51, fixed in diagonal between the same legs. The painting station 29 is constituted by a suction booth, delimited by a front wall 52, a ceiling 53 and side walls 54 and 55, of which onto the upper flat ceiling 53 it is arranged and fixed at least one aspirator 56, communicating with a traditional suction system and adapted to suck the air and the atomized painting substances that are used in the painting station 29, and that are subsequently passed through suitable filters of traditional type (not shown), installed in the plant, before being discharged outward.

In the impregnating station 28 it is arranged at least a suspended and rectilinear metallic guide member 57, supported by the back longitudinal section bar 42 and arranged parallel to this latter and along such suspended metallic guide member 57 it is slidable internally or in its upper part each part carrying bar 25 with the parts supported by the same, that is from time to time picked up by the movable shuttle element 8 from the interior of the metallic frame 5 and conveyed in correspondence of such suspended metallic guide member and lets to slide with an horizontal movement along the same metallic guide member, for introducing such part carrying bar 25 with the parts into the impregnating station 28, for effecting the impregnating phase with the impregnating agents for the parts and for extracting such part carrying bar with the impregnated parts from the impregnating station 28 at the end of the impregnating phase.

In the impregnating station 28 it is also installed a traditional impregnating unit 58 of the "flow-coating" type (see Fig. 2), that is equipped with circulation conduits 59 for the impregnating agents from time to time used, that are communicating with underlying tanks (not shown) for containing these impregnating agents, and with spraying nozzles 60 installed in the sliding path of each part carrying bar 25 with the parts supported by the same, that is introduced into the impregnating station 28. Such spraying nozzles 60 are arranged in such positions as that during the impregnating phase the parts introduced into the impregnating station may be sprayed from all sides with the impregnating agents, that are pumped from the containment tanks and let to circulate along the conduits 59 and the spraying nozzles 60.

During the spraying of the impregnating agents onto the parts, the substances dispersed downward are collected for being then re-used again, in a traditional manner.

In turn, into the painting station 29 it is also arranged at least a suspended and rectilinear metallic guide member 62 (see Fig. 1 ), supported by a rectilinear metallic section bar 63 fixed with its the end portions to the transversal section bars 43 and 44 of the second metallic frame 6, in a position parallel to and slightly spaced away from the front section bar 41 of the same frame, and fixed with this latter by means of additional short central transversal section bars 64 and 65 of reinforcement and stiffening, arranged slightly spaced away to each other and from such transversal section bars 43 and 44.

Such suspended metallic guide member 62 is subdivided in three separated and aligned to each other portions, respectively a first fixed portion 62', situated in the insertion and extraction portion of the part carrying bar 25 with the parts in the interior of the painting station 29, a central rotating portion 62", and a second fixed portion 62"' situated in the right-side portion of the metallic frame 6. Into the so formed suspended guide member 62 it is slidable internally or in the upper part each part carrying bar 25 with the parts supported by the same, that is picked up from time to time by the movable shuttle element 8 from the inside of the metallic frame 5 and conveyed in correspondence of such suspended metallic guide member 62 and lets to slide with an horizontal movement along the same metallic guide member, for introducing such part carrying bar 25 with the parts into the painting station 29, for performing the painting phase with the used paint and for extracting such part carrying bar with the painted parts from the painting station 29 at the end of the painting phase.

In the middle zone of the painting station 29 it is also installed a carrousel element 66 in correspondence of the sliding path of the part carrying bar 25 with the parts supported thereon.

The carrousel element 66 is constituted by a set of short section bars 67, identical and joined to each other with their end portions in a way to form a polygon, which section bars are also joined to each other also with at least a short central section bar 68, that is fixed below the rectilinear metallic section bar 63, in the middle zone thereof, and below such section bars 67 and 68 it is fixed a circular metallic section bar 69, that serves to allow the guide member 62" to rotate in any position around a central pivot (not shown) fixed below the same circular section bar.

In this way, each part carrying bar 25 with the parts supported thereon is inserted by the movable shuttle element 8 into the suspended guide member 62, and such bar is lets to slide in succession on to the first fixed portion 62' of the suspended guide member and then on to the central movable portion 62" of the same suspended guide member, so that in this latter position such bar with the parts is supported by this central movable portion 62", in a manner that by rotating manually or automatically such central movable portion the bar and the parts 26 hung on the same may be rotated in different positions, and that the parts may be so covered from all the sides with the paint sprayed by the spraying nozzles of the painting system (not shown) of the traditional type, that is installed into the painting station 29.

Thereafter, at the end of spraying, each bar with the painted parts is extracted by the movable shuttle element 8 from the painting station 29 with a movement opposite than the previous one, and then is brought again by such movable shuttle element 8 in the plant drying zone. Finally, the paint dripping from the parts and the parts of dispersed paint falling downward are collected in a traditional manner in the lower part of the painting station 29, for being subsequently recovered and re-used again by means of specific recovering systems, not shown in the Figures.

Referring now to figs. 8-11, it is shown the movable shuttle element 8 in a front view, a plan view, a side view and a perspective front and exploded view, respectively, which element is represented with the part carrying bar at the centre of the movable shuttle element, therefore in the working position thereof for movement, whereas in the Figs. 12 and 13 such movable shuttle element 8 is shown respectively in a front view and a plan view, which element is displaced in the working position thereof for movement, wherein one of the part carrying bars 25 with the parts 26 supported thereon is grasped for being conveyed at first at the centre of the same movable shuttle element, and then toward one of the impregnating station 28 or painting station 29.

As it is visible from such Figs. 8-11, the movable shuttle element 8 is constituted substantially by a main frame 70 of horizontal and lengthened rectilinear shape, by a front frame 71 and a back frame 72, of horizontal and lengthened rectilinear shape, that are joined as it will be described to the main frame 70, from the front part and from the back part of this main frame, respectively, and the conformation and the function of these frames will be described soon.

The movable shuttle element 8, furthermore, has such a length as to be able to be inserted into the free sliding path 7 of the present plant, for being able to slide in this latter with alternate movements, and has a length slightly greater than the distance between two part carrying bars 25 adjacent to each other, for the reason that will be described.

In particular, the main frame 70 is substantially constituted by two lengthened and rectilinear section bars 73 and 74, identical and arranged parallel and slightly spaced away to each other in the direction of the width of the movable shuttle element 8, and these lengthened section bars are joined to each other in their left-side end portion by a first transversal beam 75 and in their right-side end portion by a second transversal beam 76, and also by a short central beam 77. Along such lengthened section bars 73 and 74 there are also secured some vertical brackets 78 spaced away to each other, and shaped for supporting a relative lengthened rectilinear guide member 79 and 80, and these guide members are identical and formed by section bars joined to each other, by delimiting a correspondent central rectilinear groove 81 and 82, wherein a relative part carrying bar 25 is supported and slidable as it will be described.

Instead of supporting two part carrying bars as it results from the described example, the main frame 70 may support even one single part carrying bar 25 only, by providing in such case one rectilinear and lengthened section bar only.

On to the first transversal beam 75 there are hinged two idle wheels 83 and 84 of reduced dimensions, spaced away to each other in the length direction of the same beam and turned toward the plant drying zone, which are oriented in a direction parallel to the beam 75 and are provided with a correspondent race 85 and 86, adapted to slide in the alternate rectilinear direction along a rectilinear guide member 87, provided in correspondence of the transversal peripheral section bar 12 in an internal position with respect thereof.

In turn, on to the second transversal beam 76 there are hinged two additional idle wheels 88 and 89, identical to the previous ones, spaced away to each other in the length direction of the same beam and turned in the direction opposite to the previous wheels, which are also oriented in the direction parallel to the beam 76 and are provided with a correspondent race 90 and 91, adapted to slide in the alternate rectilinear direction along a rectilinear guide member 92, provided in correspondence of the transversal peripheral section bar 43 of the impregnating station 28 and painting station 29, in an internal position with respect thereof, which guide member is parallel to the previous guide member 87 and has the same length thereof.

In this way, by arranging all the hollowed wheels 83, 84 and 88, 89 of the main frame 70 joined to the front and the back frames 71 and 72, onto the relative rectilinear guide members 87 and 92, it is possible to let to slide the so constituted shuttle element 8 in the alternate direction for the entire length of such rectilinear guide members, for moving in this way the movable shuttle element 8 with the bars 25 and the parts 26 supported by them in different positions of the drying zone and in either one of the impregnating station 28 and painting station 29 of the plant. The alternate sliding of the movable shuttle element 8 is effected by coupling two powered gear pinions 93 and 94, supported into the front frame 71 and actuated in rotation as it will be described soon, with a correspondent lengthened rectilinear rack 95 and 96 fixed below the relative rectilinear guide member 87 and 92, for the entire length thereof. The gear pinions 93 and 94 are fixed to the free end portion of a relative horizontal lengthened shaft 97 and 98 arranged in the upper part of the front frame 71, in a position projected frontwards the same frame, of which the lengthened shaft 97 is supported in rotation into bearings (not shown) inserted into short vertical collars 99, spaced away to each other in the longitudinal direction and the lengthened shaft 98 is supported in rotation into bearings (not shown) inserted into short vertical collars 100, spaced away to each other in the longitudinal direction.

All the collars 99 and 100 are supported by the front frame 71, which is constituted by an upper lengthened rectilinear section bar 101 , the end portions of which are bent orthogonally downward, and by a metallic support structure 104 of lengthened rectilinear form, joined to such bent end portions and extended in a horizontal direction for a distance greater than the distance between the beams 75 and 76, wherein the upper section bar 101 and the support structure 104 are also joined to each other by further intermediate vertical parts 105, said collars 99 and 100 being secured in the upper portion of relative narrow vertical brackets 106 and 107, fixed in the upper part to the lengthened upper section bar 101 and in the lower part to the lengthened support structure 104. The other end portions of the relative rotating shafts 97 and 98 are coupled by means of correspondent rotating couplings 108 and 109 to a relative short horizontal driving shaft 110 and 1 1 1 rotatable housed in the upper part of a vertical gearmotor unit 1 12, applied in the upper part to the lengthened upper section bar 101 of the front frame 71, in the central position and projected forward of the movable shuttle element 8, and the electric motor 1 13 of such gearmotor unit 1 12 is connected to the electric plant installed in the present conveyor plant and is controlled into rotation by acting on to the control panel 30 of this plant, while the gear wheels (not indicated) of the gearmotor unit, which are actuated in rotation by the electric motor 113, are mechanically connected to the driving shafts 110 and 11 1, in a manner that when the electric motor 113 is actuated in rotation in either one of its rotation directions, a correspondent rotation in the same rotation direction of the driving shafts 110 and 111, and therefore also of the relative rotating shafts 97 and 98 and gear pinions 93 and 94 be determined, with consequent advancement of the movable shuttle element 8 in the same direction, thanks to the sliding of the idle wheels 83, 84 and 88, 89 on the relative rectilinear guide members 87 and 92. In order to allow the part carrying bars 25 to slide alternately along the respective lengthened rectilinear guide members 79 and 80, the correspondent grooves 81 and 82 of such guide members are shaped with an internal profile identical to and slightly greater than the outer profile of several slidable supports 1 14 (see Fig. 12), which are identical and spaced away to each other in the longitudinal direction and also slidable on to the suspended and rectilinear guide members 24 of the plant drying zone, such slidable supports being secured with a relative vertical shank 115 to the underlying upper portion of each part carrying bars 25, which is shaped flat, and in which there are fixed in the transversal direction several relative short projected studs 116, the function of which will be described hereinafter. As visible particularly from the Fig. 12, in which it is shown the movable shuttle element 8 displaced in correspondence of a part carrying bar 25 supported by a suspended and rectilinear guide member 24, it is noted that the lower portion of the rectilinear and central groove (not indicated) of the lengthened guide member 79 is aligned with the slidable supports 114 of the part carrying bar 25, so that such slidable supports may be displaced along the suspended guide member 24 and let to enter and slide in said rectilinear and central groove, when the part carrying bar 25 is drawn from the illustrated position by the movable shuttle element 8, and displaced in the manner and the position which will be described soon. In the front side of the movable shuttle element 8 a further gearmotor 117 is also installed, which is projected outwards and applied to a vertical bracket 118 secured to the front frame 71, and the electric motor (not indicated) of such further gearmotor is connected to the electric plant of the plant and controlled by the control panel of this latter, while the gear wheels of such further gearmotor engage a lengthened and continuous transmission chain 119, supported in the support structure 104 in the interior of the movable shuttle element 8 and wound around several toothed wheels 120, pivoted in different positions in the same support structure 104, in a manner that the actuation by the electric motor of the further gearmotor 1 17 in either one of the rotation directions determines the sliding of the transmission chain 1 19 and the toothed wheels 120 in the same direction. The transmission chain 1 19 has a rectilinear lower portion 119' with a length greater than the distance between the beams 75 and 76 and an extension parallel to and spaced away in the upper part of each part carrying bar 25 being transported by the movable shuttle element 8.

In the transmission chain 119 it is fixed laterally at least a short rigid rectilinear tang 121, the function of which will be described soon, which is displaced by the transmission chain in the same sliding direction thereof. In the described embodiment of the conveyor plant, in the transmission chain 119 there are mounted two tangs 121 (see Figs. 8 and 10) in positions adequately spaced away from each other, which during the sliding of the chain around the toothed wheels 120 do not interfere with the teeth of the same wheels, owing to the fact that they are fixed laterally in the chain. Of course, according to the invention also more tangs 121 may be mounted in the transmission chain 119, which perform the same function which will be described, thus without departing from the protection sphere of the present invention. In the upper portion of each part carrying bar 25 there are secured at the same height at least two studs 116 identical to each other, which in the described embodiment are adequately spaced away to each other in the longitudinal direction of the part carrying bar 25, which studs are projected for the same extent from the two lateral sides of the same bar, and are situated at such a height as to interfere with the sliding path of the tangs 121 secured to the transmission chain 119, when such tangs 121 are sliding in either one direction along the rectilinear lower portion 1 19' of the same transmission chain, in a manner to abut on to one or more projected studs 116 of the part carrying bar 25, thereby providing for entraining this latter in the same advancement direction of the transmission chain 119. In particular, when the tangs 121 are displaced by the

advancement of the transmission chain 119 in the two zones of movement reversal of the same chain, and find themselves in the rectilinear upper portion 1 19" of this latter, such tangs 12 raise themselves with respect to the relative projected stud 16 with which they are temporarily abutting, by disengaging themselves from the same stud and thereby terminating the horizontal rectilinear entrainment of the part carrying bar 25 by such tang. In this way, each part carrying bar 25 may be entrained in its rectilinear sliding path by the tangs 121 of the chain 119, when the tangs 12 are abutting only on correspondent projected studs 116 of the same bar, from a rest position in which the part carrying bar 25 with the parts 26 supported thereon finds itself in either the drying zone or the impregnation station 28 or the painting station 29 of the plant, to a position loaded on to the movable shuttle element 8, in which the advancement movement of the chain 119 is stopped, in the manner which will be described, so that the end portions of the part carrying bar 25 do not interfere with either the drying zone or the impregnation station 28 or the painting station 29 of the plant. Under this condition, the movable shuttle element 8 may then let to slide in the alternate rectilinear direction along the free sliding path 7, up to be displaced in

correspondence of the desired rectilinear suspended guide member 24 of the plant drying zone, or in correspondence of the impregnation station 28 or in correspondence of the rectilinear and suspended guide member 62 of the painting station 29. In this position of the movable shuttle element 8, the part carrying bar 25 with the parts 26 supported thereon may be displaced from its position loaded in the movable shuttle element 8, by controlling the actuation of the transmission chain 119 in the manner which will be described later on, in the advancement direction A directed leftward of the rectilinear lower portion 119 ' of the same chain, in a first operation position thereof situated in the drying zone, in which such part carrying bar supporting the parts 26 is inserted correctly in to the drying zone. On the contrary, such part carrying bar 25 may be displaced from its loaded position, by controlling the actuation of the transmission chain 119 in the advancement direction B, directed rightward of the rectilinear lower portion 119' of the same chain, in a second operation position situated in correspondence of the impregnation station 28, in which such part carrying bar supporting the parts 26 is inserted correctly in the impregnation station 28, or such part carrying bar 25 may be displaced in a third operation position situated in correspondence of the painting station 29, in which the part carrying bar supporting the parts 26 is inserted correctly in the painting station 29.

Referring now again to the Figs. 9, 10 and 11, it is noted that also the back frame 72 of the movable shuttle element 8 is constituted by a lengthened rectilinear upper section bar 122, the end portions of which are bent orthogonally downward, and by a metallic support structure 123 having lengthened rectilinear form, joined to such bent end portions and extended in a horizontal direction for a distance greater than the distance between the beams 75 and 76, wherein the upper section bar 122 and the support structure 123 are also joined to each other by further intermediate vertical parts 124. Moreover, in the back frame 72 it is also installed an additional gearmotor 125, applied to a vertical bracket 126 secured in the upper part of the upper section bar 122 and fixed in the lower part to the metallic support structure 123, identical to and provided for the same scope of the preceding support structure 104. The electric motor 127 of such additional gearmotor 125 is also connected to the electric plant of the present conveyor plant and controlled by the panel control 30 of this latter, while the gears of such additional gearmotor engage a further lengthened continuous transmission chain 128, supported in the further support structure 123 and wound around different toothed wheels 129, pivoted like the previous toothed wheels 120, in a manner that the actuation of the electric motor of the additional gearmotor 125 in either one of the rotation directions provides for sliding the further transmission chain 128 and the toothed wheels 129 in the same direction. The further transmission chain 128 has a rectilinear lower portion 128' with a length greater than the distance between the beams 75 and 76 and an extension parallel to and spaced away in the upper part from each part carrying bar 25 being transported by the movable shuttle element 8 through the lengthened guide member 80. Also in this case, in the further transmission chain 128 there are secured laterally some short rigid rectilinear tangs 130 in the same side positions of the chain and which are displaced by such chain in the same sliding direction thereof.

The number of tangs 130 which is utilized also here is identical to that of the previous transmission chain 1 19. Furthermore, also in this case in the upper portion of each part carrying bar there are fixed at the same height at least two short projected studs (not indicated), identical to and performing the same function of the preceding studs 1 16 to abut on to one or more tangs 130 of the transmission chain 128, thereby providing for again the entrainment of the part carrying bar 25 in the same advancement direction of the same transmission chain. Therefore, also in this case each part carrying bar 25 with the parts 26 supported thereon may slide along the lengthened rectilinear guide member 123 of the movable shuttle element 8, for being displaced in the same way and with the same movements in the same previously described operative positions of the part carrying bars 25 slidable in the rectilinear guide member 79 of the movable shuttle element 8.

In order to join the main frame 70 to the front frame 71 and the back frame 72 of the movable shuttle element 8, in the front frame 71 there are mounted in the transversal direction two short side beams 131 and 132 and a short central beam 133 in a position coinciding with the position of the of the central beam 77, which beams are turned toward the main frame 70, while in the back frame 72 there are mounted in the transversal direction two short side beams 134 and 135 and a short central beam 136 in a position coinciding with the position of the central beam 77, which beams are turned toward the main frame 70. In this way, the beams 131 , 132 and 133 of the front frame 71 are brought into contact with and joined to correspondent plates 137, 138 and 139 fixed in the lengthened section bar 73, while the beams 134, 135 and 136 of the back frame 72 are brought into contact with and joined to correspondent plates (not indicated) fixed in the lengthened section bar 74, thereby forming the movable shuttle element 8.

Turning now to the Figs. 12 and 13, shown therein is a movable shuttle element 8 displaced in correspondence of the plant drying zone, in a determined position, in order to draw from such drying zone a part carrying bar 25 with the parts supported thereon, which must be still treated and therefore should be transported by such movable shuttle element 8 at first in the impregnation station 28 and thereafter in the painting station 29, so as to be covered respectively with the impregnating substance and the paint, or such parts should be transported solely in one of the two impregnation station 28 or painting station 29, and at the end of the treatment they must be returned back with reverse movements in the drying zone, and let to stay here to dry for an established duration.

In this position of the movable shuttle element 8, in which this latter had been transported automatically by means of control of the operative program selected in the control panel of this conveyor plant, the advancement of the movable shuttle element 8 was arrested by one or more position detecting sensors (not shown), mounted in the plant drying zone and connected to the electric circuit of the present conveyor plant and installed in

correspondence of both this operative position, in which a relative part carrying bar 25 is supported in the drying zone, and of the other positions in which the part carrying bars 25 are supported or may be supported in the same drying zone.

Then, in this case the lengthened guide member 80 of the movable shuttle element 8 finds itself aligned with and slightly spaced away in front of the correspondent end portion of the part carrying bar 25 arranged in this position, in a manner that such part carrying bar may then let be sliding along such guide member, as described previously. Besides, in this position of the part carrying bar 25, the other end portion of the part carrying bar 25 finds itself into contact with at least another suitable sensor for detecting the end-of-stroke position (not indicated), connected in the electric plant of the present conveyor plant and mounted in this same position in the plant drying zone. Under this condition, all the detecting sensors signal the presence of the part carrying bar 25 in its rest position in the interior of the drying zone, thereby arranging the movable shuttle element 8 for drawing this part carrying bar 25 with the parts 26 supported thereon. In this way, the movable shuttle element 8 is controlled by the control device of the present plant, which is connected in the electric circuit of the same plant, to actuate the transmission chain 1 19 in the sliding direction B, so that the tangs 121 fixed in this chain engage the relative projected studs 116 of the part carrying bar 25, thereby entraining this latter in the same advancement direction of the same chain, and consequently provide for displacing this part carrying bar 25, with the parts 26 supported thereon, in the interior of the movable shuttle element 8 with a longitudinal rectilinear movement. In the movable shuttle element 8 there are mounted some detection sensors (not indicated) of the end-of-stroke position of the part carrying bar 25, which are situated in the end portions of the lengthened guide members 79 and 80, and serve to signal the end-of-stroke position of the part carrying bar 25, thereby activating the plant control device to stop the advancement of the relative transmission chain, and therefore also the displacement of the part carrying bar 25. In this manner, when each part carrying bar entrained by the relative transmission chain of one of the two lengthened guide members 79 and 80 comes into contact with either one of its end portions with a relative detecting sensor here mounted in the movable shuttle element 8, this sensor activates the plant control device to stop the chain advancement, and therefore of the part carrying bar, in the loaded position of the same part carrying bar in which it is completely inserted in the movable shuttle element 8, and such sensor allows the plant control device to displace the same shuttle element along the free sliding path 7 of the plant.

Then, in the present case when the transmission chain 1 19 has completely inserted the part carrying bar 25 in the interior of the movable shuttle element 8, and the end portion of such part carrying bar is arrived to contact the relative end-of-stroke sensor, this latter activates the plant control device to stop the advancement of such chain 119, and therefore of the part carrymg bar 25 too. Then, under this condition, the sensor enables the plant control device to control the advancement of the movable shuttle element 8 along the free sliding path 7, up to the impregnation station 28 or the painting station 29, depending on the operative program to be performed being set in advance in the plant control panel 30. In each one of these stations 28 and 29 there are mounted some position detecting sensors, connected in the plant electric circuit and constituted by both at least a sensor for detecting the presence of the part carrying bar 25 inserted in the movable shuttle element 8, in correspondence of the relative impregnation station or painting station, and by at least a sensor for detecting the end-of-stroke position of the part carrying bar 25 being introduced in the interior of the relative impregnation station 28 or painting station 29.

Then, in the first case each presence sensor (not indicated) is mounted at the end portion of the rectilinear and suspended guide member 57 of the impregnation station 28 or the rectilinear and suspended guide member 62 of the painting station 29, on to which guide member the part carrying bar 25 is supported and let to slide, and the end portions are situated near the plant rectilinear guide member 92, while in the second case each end-of- stroke sensor (not indicated) is mounted at the other end portion of such rectilinear and suspended guide members. In this way, when the movable shuttle element 8 with the part carrying bar 25 supported thereon is arrived in correspondence of the presence sensor of the impregnation station 28 or the painting station 29, such sensor detects the presence of this movable shuttle element and activates the plant control device to stop at first the advancement in the same direction of the movable shuttle element 8 and then to control the sliding of the transmission chain 119 in the direction B, up to the part carrying bar 25 with the parts 26 supported thereon has been inserted correctly along the relative suspended guide member 57 or 62 of the correspondent impregnation station 28 or painting station 29. When the part carrying bar 25 is arrived into contact with the relative end-of-stroke sensor of either one station, this sensor activates the control device to stop at first the

advancement of the same bar and subsequently to control the beginning of the

impregnation phase or the painting phase. At the end of this operative step, the plant control device controls the sliding in the direction A of the transmission chain 1 19 of the movable shuttle element 8, so that such chain provides for hooking as already explained the part carrying bar 25 with the treated parts, by extracting it from the relative treatment station and inserting it again in the interior of the lengthened guide member 80 of the movable shuttle element 8, until this part carrying bar arrives into contact of the end-of- stroke sensor situated at the opposite end portion of the lengthened guide member 80, which activates the control device to stop the advancement of the part carrying bar in the same direction, under the condition in which this latter is completely inserted with the treated parts in to the movable shuttle element 8. In this way, such sensor enables the plant control device to control the advancement in the opposite direction of the movable shuttle element 8 along the free sliding path 7, until such movable shuttle element 8 is arrived in correspondence of the position of the drying zone in which the part carrying bar 25 with the treated parts supported thereon must be introduced in the interior of the same drying zone. Then, in this position the presence of the movable shuttle element 8 is detected by the relative detecting sensor, mounted in the drying zone, which activates the plant control device at first to stop the advancement of the movable shuttle element 8, and thereafter to provide for sliding the transmission chain 1 19 in the direction A, with consequent transport and sliding of the part carrying bar 25 with the treated parts supported thereon along the relative suspended guide member 24 installed in this position, up to such part carrying bar comes into contact with the end-of-stroke sensor of the suspended guide member 24, which provides for activating the plant control device to stop the advancement and the insertion of the part carrying bar in to the drying zone, under the condition in which the part carrying bar 25 stays in this rest position, and its treated parts are so let to dry for the necessary duration for being dried. In this manner, the movable shuttle element 8 is arranged for being displaced as described above in another position of the drying zone, for drawing additional part carrying bars with the relative parts and conveying them with the same described sequences in either one of the above described treatment stations. Instead of - conveying one part carrying bar 25 at once only, as described above, the movable shuttle element 8 may convey also a second part carrying bar 25, with the parts 26 supported thereon, so that in this case while one of the part carrying bars 25 is displaced from the drying zone to either one of the impregnating station 28 or the painting station 29, and vice versa, the other one of the part carrying bars 25 may be displaced at the same time in other positions and treatment stations of the conveyor plant, so as to submit the parts 26 supported thereon to different operative phases, thereby reducing the displacement movements of the movable shuttle element 8 and the needed working times for performing these operative phases of the parts supported by the other one of the part carrying bars. In the Fig. 14 it is now represented schematically a plan view of a conveyor plant according to the invention made with the same components and a different arrangement with respect to the previously described plant, and this plant has dimensions larger than the previous one, and is still constituted by a loading zone 140 of the part carrying bars 25 with the parts 26 to be treated on their surfaces, acting also as unloading zone of the treated and dried parts, the plant being also constituted by a drying zone 141 separated from the loading/unloading zone 140 and aligned with and approached to this latter, in which zone the treated parts are put temporarily and automatically, in order that such parts might be dried completely. Also the environment of this drying zone is delimited by insulating panelling (not indicated), inside which the dehumidified and heated air is circulated by means of an air conveying and heating plant of per se known type, which is indicated schematically with the reference numeral 142, in order to make easier the drying process of the parts. Moreover, the present conveyor plant is constituted by a rubbing zone 143 separated from the drying zone 141 and aligned with and approached to this latter, in which zone the parts 26 are put automatically after the impregnation of their surface, so as to rubber the surface of the same parts in a traditional manner before to be painted, for which reason the components housed into this zone aren't described.

The present plant is still constituted by an impregnation station 144 and by a painting station 145 which are made and operate like the analogous preceding stations, which are aligned and separated to each other by a further drying zone 146, identical to the previous drying zone 141 and performing the same function thereof, and also communicating with the air conveying and heating plant 142, wherein such stations 144, 145 and drying zone 146 are spaced away from the preceding zones for delimiting still a free sliding path 147 for a movable shuttle element 148, identical to the above described one and slidable alternately along this path with the same operative sequences.

Besides, in this case the impregnation station 144 includes the same component parts of the previous station, which are marked with the same reference numerals, and also includes an automatic storage warehouse 149 with limited size, in which the just impregnated parts are arranged on to supports (not shown) and let to drip from the sprayed impregnating agent, for being subsequently drawn again by the movable shuttle element 148.

In turn, the painting station 145 may be made with the same components of the preceding station or also with different components, in order to be able to paint the parts by means of robot or another type of automatic/manual painting machine (all these components aren't indicated). In the Fig. 15 it is shown the conveyor plant with the components and the arrangement of the Fig. 14, comprising another movable shuttle element 148' slidable alternately along the free sliding path 147, together with the first movable shuttle element 148. The presence of this additional movable shuttle element 148' serves to make faster the displacements of the part carrying bars 25 with the parts 26 supported thereon and to reduce the waiting times among the various operative phases of the plant, and consequently for increasing the productivity of the same plant. In the Fig. 16 it is shown a schematic front view of a part of the loading/unloading station 140 and the impregnation station 144 with the parts 26 supported by the part carrying bars 25. In the Figs. 17-33 there are now shown schematically the different operative sequences of an example of a treatment cycle of the parts in the conveyor plant of the Fig. 14.

In the Fig. 17 it is noted that one or more operators 150 are loading the parts to be treated on to the part carrying bars of the loading/unloading zone 140. The warehouse of this zone may be loaded fully or also partially. Once all the desired part carrying bars have been loaded, an operator 150 will provide to select in the plant control panel 30 the program of the cycle intended to be performed. Under this condition, then, the cycle starts and the movable shuttle element 148 which finds itself in correspondence of the drying zones 141 and 146, without parts loaded thereon, moves itself for going to draw from the

loading/unloading zone 140 the selected part carrying bar with the parts to be treated. In the Fig. 18 it is noted that the movable shuttle element 148 has displaced itself in the loading/unloading zone 140 and has positioned itself in correspondence of the part carrying bar to be drawn, and is drawing automatically this latter by displacing it progressively at the centre of the same element. In the Fig. 19 it is noted that the movable shuttle element 148 moves itself, together with the part carrying bar with the relative parts loaded thereon, for bringing the assembly part carrying bar and parts in the selected treatment zone, in the example indicated in the impregnation station 144. In the Fig. 20 it is noted that the movable shuttle element 148 has displaced itself in the position aligned with the suspended guide member 57 of the impregnation station 144, and provides for unloading

progressively the part carrying bar, with the parts supported thereon, from the movable shuttle element 148, by displacing all in the interior of the impregnation station 144, and letting to slide the part carrying bar 25 along the suspended guide member 57. At this point, when all has been completely introduced in the impregnation station 144, it begins the impregnation phase of the parts. In the Fig. 21 it is noted that at the end of the impregnation of all the parts, the part carrying bar with the relative impregnated parts has been moved into the storage warehouse 149 of the impregnation station 144, and such parts are let to drip for an established time, in which their part carrying bar is displaced progressively toward the outlet of the storage warehouse 149.

At this point, while the parts are dripping, the movable shuttle element 148 displaces itself toward the outlet position of the storage warehouse 149 and positions itself for drawing the part carrying bar with the dripping parts, which has been displaced progressively toward this outlet zone of the storage warehouse 149 and such part carrying bar with the relative parts in this way arranges itself in this outlet position.

In the Fig. 22 it is noted that the movable shuttle element 148 has been displaced in the outlet position from the impregnation station 144 of the part carrying bar 25 with the impregnated parts, when the dripping thereof is ended, and such movable shuttle element 148 is drawing progressively the part carrying bar with the impregnated parts, and loads these latter in its interior. Once the part carrying bar, with the relative impregnated parts, has been positioned at the centre of the movable shuttle element 148, this latter displaces itself toward the next plant working zone, in this example the rubbing zone 143.

In the Fig. 23 it is noted that the movable shuttle element 148 is arrived in to the pre- established position of the rubbing zone 143, and it provides for unloading automatically the part carrying bar 25 with the relative parts, by displacing it progressively in the interior of the rubbing zone 143. In the Fig. 24 it is noted that the parts supported by the part carrying bar 25 introduced in to the rubbing zone 143 are rubbed by an operator 150. In the Fig. 25 it is noted that at the end of rubbing the parts in to the rubbing zone 143, the movable shuttle element 148 draws from the rubbing zone 143 the part carrying bar 25 with the rubbed parts and displaces itself in the position aligned with the painting station 145. In the Fig. 26 it is noted that the movable shuttle element 148 is displaced in the position aligned with the suspended guide member 62 of the painting station 145 and unloads from such element the part carrying bar 25 with the parts supported thereon, by putting automatically the whole along the suspended guide member 62 of the painting station 145. In the Fig. 27 it is noted that the part carrying bar 25 with the parts supported thereon has been completely introduced in to the painting station 145, so that it begins the painting of the parts with the automatic painting machine (not indicated), and the painting continues until all the parts are completely painted.

In the Fig. 28 it is noted that as soon as all the parts have been painted, the movable shuttle element 148 draws the part carrying bar 25 with the painted parts and slides with a reverse movement along the suspended guide member 62 of the painting station 145, by loading such part carrying bar with the parts in to the movable shuttle element 148, which starts to displace itself toward one of the drying zones.

In the Fig. 29 it is noted that in the case in which no empty places are available in the warehouse of the drying zones, for receiving such part carrying bar 25 with the relative parts, the movable shuttle element 148 arranges itself with the other lengthened guide member thereof (in this case, the guide member 79 in which the part carrying bar isn't inserted) in the position aligned with the suspended guide member 24 of another part carrying bar puts in the drying zone (in this case, the zone 141) and the parts of which have already been dried in a previous working cycle, in a manner that the movable shuttle element 148 draws this part carrying bar by letting it to slide along the lengthened guide member 79 and introducing it in the interior of the same element, thereby making free a place in the drying zone 141, in which the part carrying bar 25 with the painted parts can be disposed. In the Fig. 30 it is noted that the movable shuttle element 148 displaces itself in a manner to position its lengthened guide member 80, in which the part carrying bar 25 with the painted parts is housed, in the position aligned with the suspended guide member 24 of the place made free in the drying zone 141, for introducing such part carrying bar with the parts supported thereon into this freed place of the same drying zone, and in the Fig. 31 it is noted that such part carrying bar 25 with the parts is being introduced in the freed place of the drying zone, and it is completely introduced in this place, for letting dry all the painted parts. In the Fig. 32 it is noted that the movable shuttle element 148 is being moving toward the unloading zone 140 of the conveyor plan, in a manner that it may be unloaded the part carrying bar 25 with the parts, which has been loaded in the lengthened guide member 79 of the movable shuttle element 148, as described and visible in the Fig. 29. In the Fig. 33 it is noted that such movable shuttle element 148 is arrived in the unloading zone 140, and arranges itself with the lengthened guide member 79 in the position aligned with the suspended guide member 24 of the place made free of this latter, and the part carrying bar 25 with the parts is completely introduced in to this free place, so that all the painted and dried parts may be drawn by the operator 150.

There are so evident the advantages achieved with the conveyor plant according to the present invention, which are substantially the following :

depending on the needs, the movable shuttle element is able to draw/put the part carrying bars, with the relative parts, in any position without following a sequential order, but by moving the desired part carrying bar only ;

it is possible to treat also parts to be coloured with different colours, the part carrying bars of which could be disposed casually in any position in the present plant, and the same can be drawn/disposed selectively by the movable shuttle element ;

it is possible to perform more operations simultaneously, thereby allowing to perform different operations on to different part carrying bars. Therefore, it isn't necessary to follow a precise sequential order for the various kinds of workings ; the so realized plant occupies less space under the same treated parts supported by the part carrying bars, with consequent better exploitation of the space available in the working site;

the plant can be made fully automatic, with the possibility to start from a manual movement of the part carrying bars and to made automatic the operations if requested ; possibility to utilize also two or more movable shuttle elements, for speeding the various operative phases, depending on to the size of the plant.