Conveyor for sorting generic products to packaging or cartoning machines
BACKGROUND OF THE INVENTION 
     The present invention relates to a conveyor for sorting generic products to packaging or cartoning machines. 
     More specifically, the invention relates to conveyors of the type disclosed in European Patent Application No. 91110513.8 filed on Jun. 25, 1991 in the name of the same Applicant, which comprise at least one main conveyance unit, typically two or more main conveyance units, with respective conveyor belts which move in a main conveyance direction, and at least one sorting unit provided with an auxiliary belt which moves in the main conveyance direction and with a sorting belt which moves at right angles to the main direction; the sorting unit is interposed between two main conveyance units. 
     In conveyors of this type, used to move food products, the main units and the sorting unit are subject to a considerable accumulation of residues left by the products conveyed, particularly residues of flour, sugar, preserves, jams and the like. These residues soil and cake not only the conveyor belts but also the guiding elements, the actuating kinematic systems and in general the entire structure of the machine, severely compromising the hygiene of the products handled and the functionality of the system. 
     Accordingly, it is necessary to intervene periodically to accurately clean these main and sorting units, particularly by removing the conveyor belts and cleaning them accurately or replacing them with others subjected to a prior cleaning treatment. 
     Currently, in known conveyors these operations are very complicated and onerous and require the intervention of skilled personnel that disassembles and reassembles the conveyance units. These disassembly, cleaning and reassembly operations usually use up an entire work shift. Considering that the frequency of the required cleaning intervention is approximately one intervention every 8-10 work shifts, the time wasted for this task is comprised between 12 and 10% of the actual production time. 
     These considerable downtimes, together with the costs of the skilled personnel currently involved in these disassembly, cleaning and reassembly operations, make it very onerous to manage these conveyance systems, with a consequent loss in the economic yield of the system. 
     SUMMARY OF THE INVENTION 
     The aim of the present invention is to eliminate these severe drawbacks with improvements to the main and sorting units of the conveyor which allow to drastically reduce the time required for their cleaning and/or ordinary maintenance and to avoid the intervention of skilled personnel (maintenance team ) for the disassembly and reassembly of the machines. 
     Within the scope of this general aim, the invention improves the main and sorting units of the conveyor, allowing to remove and reposition the conveyor belts and the rollers for the movement of said belts in a very short time, without the aid of any tool and with very simple operations which can be performed easily by the same personnel that monitors the operation of the system. 
     Another important and particular object of the invention is to improve conventional conveyors of the specified type, facilitating access to the sorting units, each placed between two main units. In particular, another improvement according to the present invention has the purpose of allowing rapid and easy removal of the sorting unit or units, which can be replaced in a very short time with other units on which cleaning or maintenance operations have already been performed. 
     According to the present invention, this aim, these objects and others which will become apparent from the following detailed description are achieved by virtue of the fact that each one of said main conveyance units of the conveyor has a frame for supporting the respective conveyor belt which is supported so that it is cantilevered from one side of the base structure, or table, to allow to fit and remove said belt at the other side of the table, which has no supports interfering with said belt. 
     Another characteristic of the conveyor according to the invention is the fact that each one of the sorting units comprises a base structure which is supported by respective posts provided with castors, and that said base structure is provided with retention guides accommodated in sliding seats supported by the adjacent main units, with respect to which said sorting units can be extracted by means of a movement at right angles to the main conveyance direction, allowed by said castors. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will become apparent from the following detailed description and with reference to the accompanying exemplifying drawings, wherein: 
     FIG. 1 is a longitudinal and partial schematic sectional view of the conveyor according to the invention, illustrating a pair of main conveyance units and a sorting unit interposed between them; 
     FIG. 2 is a schematic transverse sectional view of a main conveyance unit, taken along the plane II--II of FIG. 1; 
     FIG. 3 is a partial perspective view of the conveyor of FIG. 1; 
     FIG. 4 is a detailed perspective view of a main conveyance unit; 
     FIGS. 5 to 7 are enlarged-scale views of details of FIG. 4; 
     FIG. 8 is a perspective view, similar to FIG. 4, illustrating the method for removing the belt of a main conveyance unit; 
     FIG. 9 is a perspective view, similar to FIG. 3, illustrating the method for removing a sorting unit; 
     FIG. 10 is a detailed perspective view of a sorting unit. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIG. 1, the reference numeral 10 generally designates the conveyor, which comprises two or more main conveyance units 11 and at least one sorting unit 12 interposed between them. The main conveyance units 11 have respective conveyor belts 13 which define a main conveyance direction T for generic rows of products, such as food products and the like, and the sorting unit 12 is provided with an auxiliary belt 14 which moves in the main conveyance direction and with a sorting belt 15 which moves at right angles to the main direction, defining a corresponding direction for the sorting of said products which is at right angles to said main direction T. Each one of the main conveyance units 11, which are arranged so that they face each other and are mutually adjacent, comprises a pair of sorting arms 16 A  -16 B  provided with guiding rollers for the respective conveyor belt 13, and the auxiliary belt 14 and the sorting belt 15 of the sorting unit 12 are arranged at a lower level with respect to the main conveyance plane defined by the belts 13. The arms 16 of the main units 11 are mutually adjacent, and each one can assume, when moved by corresponding actuators (not shown), a raised conveyance position, which is co-planar with respect to the main conveyance plane, and a lowered sorting position, in which they arrange themselves tangent to the auxiliary belt 14 of the sorting unit 12. 
     Each main conveyance unit 11 has its own motor M P  for moving the belt 13 and is constituted by a table-like supporting structure provided with posts 21 for resting on the ground. The supporting structure is provided with a plurality of rollers 22 for the resting and sliding of the lower portion of the belt 13, with at least one tension roller 23 and with a series of removable plates 24 which form a supporting surface for the upper portion of said belt. 
     According to the present invention, the table-like structure is cantilevered to allow, in accordance with the stated aim and objects, easy lateral extraction of the belt 13 after slackening the tension roller 23. For this purpose, the structure comprises a first strong base frame 20 which is supported by the posts 21 and is formed by two box-type longitudinal beams 25 A  -25 B  connected by cross-members 26. The base frame 20 supports, at the beam 25 A , a series of upright-like supports 27 which are rigidly jointed to said beam by means of fixing plates. In turn, the supports 27 support in a cantilevered manner a second frame 28 constituted by side members 29 A  -29 B  connected by cross-members 30. The pair of sorting arms 16 is articulated to one end of the side members 29 by means of a supporting and articulation pivot 31. 
     The arms 16 bear a first roller 30 A  for guiding the upper portion of the belt 13 and a second roller 30 B  for supporting the lower portion of said belt. The second roller 30 B  is supported at the ends of extensions of the arms 16 which are directed toward the side members 29 of the frame 28. On the arm 16 B  arranged at the side member 29 B  on the cantilevered side of the frame 28, the extension which forms the support for the roller 30 B  is connected to said arm by means of a removable plate 32, and a gap 33 (FIG. 5) is formed between the arm and the extension, allowing the lateral extraction of the belt 13, as better described hereinafter. 
     The side member 29 B  on the cantilevered side of the frame 28 is provided with front and rear supports 34-35 suitable to engage corresponding supporting plates 36-37 that ensure the stability of the frame 28 during the operation of the conveyor. The supporting plates 36 and 37 are pivoted to the corresponding beam 25 B  of the base frame and can assume an active position, shown in dashed lines in FIGS. 6 and 7, and an open position, shown in solid lines in said figures. In the active position, the plates 36-37 engage the corresponding supports 34-35 of the side member 29 B  ; in the open position, the plates move away from the supports, and corresponding gaps 38-39 (FIGS. 6-7), suitable to allow said lateral extraction of the belt, are formed between said supports and the beam 25 B . 
     Barriers 40 are interposed between the base frame 20 and the cantilevered frame 28 and are constituted by light removable housings which laterally close the structure of the conveyor; these barriers are provided with known snap-action retention and engagement means, not shown in the figure. 
     The described structure allows, in accordance with the stated purposes, to easily disassemble the main unit for cleaning and/or maintenance and particularly to easily remove the belt 13 which is removed from the frame 28 at the cantilevered side thereof. 
     For this purpose, the barriers 40 are removed first; then the plates 36-37 are rotated into the open position and the plate 32 of the arm 16 B  is removed. The tension roller 23 is furthermore slackened to loosen the belt 13, and then said belt is removed laterally in the direction of the arrows F, as clearly shown in FIG. 8. Naturally, belt reinstallation proceeds in reverse to what has been described above. 
     Removal of the belt exposes the plates 24 and the guiding rollers 22. Said rollers are provided with end pivots which are accommodated in forks of respective supporting uprights 41 and can thus be easily removed, after removing the plates 24, by pulling upward. 
     As clearly shown in FIGS. 1, 9 and 10, the sorting unit 12 is in turn provided with a base structure 50 which supports the motor M S  for moving the belt 15 and is supported by supporting posts 51 which end with respective castors 52. Said base structure 50 is also provided with guides 53 accommodated in corresponding sliding seats 54 provided on the front side and respectively on the end side of the main conveyance units 11 between which said sorting unit 12 is interposed. 
     With this arrangement, and by virtue of the presence of the castors 52, each sorting unit 12 can be removed by sliding it out at right angles to the main conveyance direction T, as clearly shown in FIG. 9, and can be rapidly replaced with a similar sorting unit previously subjected to cleaning and/or maintenance operations. 
     FIG. 10 shows that these operations for cleaning the sorting unit 12 are in turn significantly facilitated by virtue of the fact that the auxiliary belt 14 of said unit is supported by an oscillating frame 55 which is pivoted to the base structure 50 by means of removable supports 56 which are rigidly coupled to said structure by means of threaded pins provided with a knob 57. By loosening these pins it is possible to easily remove the frame 55 after moving it into the tilted position of FIG. 10 by means of handles 58. 
     It is possible to remove the belt 14 from the frame 55 and to fit said belt onto said frame by respectively pulling it off and fitting it on parallel to the longitudinal direction of said frame; the belt is loose by virtue of the fact that its lower portion, upon the rotation of the frame 55, no longer makes contact with one or more tension rollers, not shown, which are supported by the base structure 50. 
     Naturally, the effects of the present invention also cover models which achieve equal utility by using the same innovative concept.