Patent Publication Number: US-2015068124-A1

Title: Support and operating device of sliding doors, in particular for wardrobes

Description:
The invention relates to a support and operating device for sliding doors, in particular for wardrobe cabinets, the doors of which are made of the type sliding in an alternate longitudinal direction along upper and lower rectilinear guides, attached respectively to the bottom and top of the relative cabinet, and such doors are operated in alternate longitudinal directions of sliding in positions coplanar to each other, from the open position to the closed position, and vice versa. 
     Support and operating devices of sliding doors for cabinets are known of, the doors of which are fitted with wheels sliding in an alternate longitudinal direction along two relative rectilinear guides, which are attached parallel to each other respectively at the bottom and at the top of each cabinet, and appropriately distanced from each other in the direction of the depth of the cabinet, so that each door can slide along the respective guides, parallel to the other door and to the front of the cabinet, independently of the other door. This widespread system of opening and closing the cabinet doors, despite being practical and space-saving in that the doors do not rotate around hinges but slide in an alternate longitudinal direction in parallel positions to each other, does not permit a front wall of flat and uniform doors to be achieved, thereby determining an unattractive aesthetic effect. 
     Support and operating devices of sliding doors for cabinets are also known of, the doors of which also slide in an alternate direction, no longer in parallel positions but in coplanar positions to each other, so that in the closed position of the doors a flat, uniform front wall is obtained, aesthetically pleasing and appreciable. In these opening and closing systems of the cabinet doors, the doors are no longer operated separately from each other, but are operated in symmetrical directions to each other, and move from a closed position in which they are in a slightly recessed position in the direction of depth of the cabinet, and parallel to each other, to an open position in which they are first shifted forwards by a limited stroke and then made to slide laterally into the desired position, parallel to the front face of the cabinet, along rectilinear guides attached to the top and to the bottom of the cabinets. To such purpose, the support and operating devices of the doors are shaped so that the right side of the doors always moves together with the left side of the doors, and so that this synchronism is also ensured between the upper and lower part of such doors. The currently existing support and operating devices are made using systems of levers and tie-rods that act on carriages which, by means of particular profiles, support the doors and determine the sliding guides for the door shifted forwards and predisposed for alternate lateral sliding. The present invention sets itself the task of making a support and operating device for sliding doors, in particular for wardrobe cabinets, suitable for still determining the operating of the doors with a forward movement and alternate lateral sliding, as currently occurs for doors coplanar with each other in a closed position, while using however simpler and cheaper construction and assembly mechanisms than those currently utilised. 
     This support and operating device is made with the construction characteristics substantially described, with particular reference to the appended patent claims. 
    
    
     
       The invention will be more clearly comprehended from the following description, made by way of a non-limiting example and with reference to the appended drawings, wherein 
         FIG. 1  shows a front perspective view of a cabinet incorporating the support and operating device according to the invention, with one door moved to the open position and two doors moved to the closed position; 
         FIG. 2  shows a rear perspective view of a door of the cabinet in  FIG. 1 , with the relative component parts fitted permitting the longitudinal sliding thereof; 
         FIG. 3  shows a perspective view from above and in front of the upper group of component parts of a door of the cabinet in  FIG. 1 ; 
         FIG. 4  shows an exploded and rear perspective view of the component parts of the upper group of the door in  FIG. 3 ; 
         FIG. 5  shows an exploded and frontal perspective view of the lower group of component parts of a door of the cabinet in  FIG. 1 ; 
         FIGS. 6 and 7  show a perspective view respectively from above and below of one of the component parts of the lower group in  FIG. 5 , detached from such lower group; 
         FIG. 8  shows a front perspective view of the component part in  FIGS. 6 and 7 , fitted to the lower group in  FIG. 5 ; 
         FIG. 9  shows a cross-sectioned view in a longitudinal direction of the upper group and of the lower group of component parts of a door of the cabinet, moved to the closed position; 
         FIG. 10  shows, in the same view as  FIG. 9 , the door moved to a partially open or closed position; 
         FIG. 11  shows a ground view of the upper part of two doors adjacent to each other, one of which is shifted forward to be moved to the open position, and the other of which is moved to the closed position; 
         FIG. 12  shows, in the same view as  FIG. 9 , the door moved to an open position. In the aforesaid drawings, a support and operating device of sliding doors, in particular for cabinets according to the present invention is represented, constructed and functioning in the manner which will be described and suitable for determining the support and operating and sliding of the doors in alternate longitudinal directions in positions coplanar to each other, wherein the doors are operated so as to shift from a closed position in which they are adjacent and aligned with each other and in relation to the front of the cabinet, to an open position in which they are first shifted forwards by a limited stroke and then made to slide laterally into the desired position, parallel to the front face of the cabinet, and vice versa. 
     
    
    
     In particular,  FIG. 1  shows a cabinet  5  fitted with front doors, in the example composed of three flat doors  6  identical to each other and each incorporating the present support and operating device of the doors, while  FIG. 2  shows a door  6  fitted with the relative component parts of the present device permitting the longitudinal sliding thereof. In  FIG. 1  it may be noted that the cabinet  5  is delimited by a flat rear back  7 , parallel to the doors  6 , by two lateral flat sides  8  and  9 , parallel and distanced from each other in a longitudinal direction, by a distance slightly greater than the length of the three doors  6 , by a flat upper top (not shown), attached above the doors  6 , to the back  7 , and to the sides  8  and  9 , and by a flat lower bottom  10 , parallel to the top and distanced from the same by a distance slightly greater than the height of the doors, as well as being attached under the doors  6  to the back  7  and to the sides  8  and  9 . The doors  6  are fitted with handles such as for example two lateral handles  11  and  12 , to move said doors from the closed position to the open position and vice versa. 
     In the same figure it may also be noted that the central doors and right side door are moved to the closed position, in which they are adjacent and aligned with each other, while the left side door is moved to the open position, in which it is moved to the front of the closed doors, and parallel thereto, thereby making the inner space inside the cabinet accessible, which in the example illustrated is divided by an intermediate horizontal shelf  13  into an upper half space  14  and a lower half space  15 . 
     In the cabinet thus shaped, in each door  6  a support and operating device of the door according to the invention is fitted, which is composed substantially of an upper group of component parts and of a lower group of component parts, made as will be described, of which the upper group is installed and attached in a free upper space of the cabinet  5 , delimited between the relative overlying top portion of the cabinet itself and a horizontal shelf  16 , attached between the lateral sides  8  and  9  and composing the upper wall of the upper half space  14  of the cabinet. 
     In turn, the lower group is installed and attached in a lower free space of the cabinet  5 , delimited between the relative underlying bottom portion  10  of the cabinet itself and an overlying horizontal shelf  17 , defining the end wall of the lower half space  15  of the cabinet. In  FIGS. 3 and 4  each upper group of the support and operating device of the relative cabinet door will now be described in detail, which is substantially composed of a metal, box-like structure  18  formed of a flat bottom base  19 , which may be the same length or not as the relative door  6  and have a slightly lesser depth than the corresponding portion of the free upper space, said bottom base  19  being orthogonally bent along its longitudinal sides, thereby forming respectively a flat front rim  20  and a flat rear rim  21  identical to each other. The box-like structure  18  thus realised is suitably attached above the horizontal shelf  16 , in the position corresponding to each door  6 . In the rear part of the flat bottom  19  a sliding or mobile carriage  22  is housed formed of an elongated profile  23  of a parallelepiped shape, being shorter in length than the length of the bottom base  19  and of limited width, said elongated profile being attached at its ends to a first and a second flat profile element  24  and  25 , identical to each other, each of which is shaped with a central body  26  having a vertical extension, adaptable and attachable by means in themselves known against the corresponding end of the elongated profile  23 , and with a lateral horizontal arm  27  forming a 1st class lever arm, projecting from the central body  26  in a rear direction of the flat bottom  19 , as well as fitted with a through hole  28  at its end, each flat profile element described lastly being shaped with a short lateral protrusion  29 , fitted with a through hole  30  and projecting from said central body in the opposite direction to that of the horizontal arm  27 , for the reason described below. Such profile elements  24  and  25  are attached against the ends of the elongated profile  23 , so that both horizontal arms  27  face the rear rim  21  of the bottom base  19  and their short protrusion  29  faces towards the front rim  20  of said bottom base, thence between the horizontal lever arms  27  of both said profile elements, a first and a second toothed reel  31  and  32  of reduced diameter, identical to each other, are applied and attached, which in turn are inserted and attached inside the relative lateral cavities  33  of a rigid torsion bar, preferably metal  34 , of an elongated cylindrical shape, which is housed in the longitudinal direction of the bottom base  19 , for almost its entire length and slightly detached from it, so that such torsion bar  34  can be operated in rotation, together with the relative toothed reels  31  and  32 , in both its directions of rotation, in the manner and for the purpose described below. As can be seen, each toothed reel  31  and  32  is attached in a non-motorised manner against the relative end of the torsion bar  34 , by inserting a bolt or screw  35  through the through hole  28  of the horizontal arm  27  and screwing the same into a corresponding threaded hole  36  of the relative toothed reel. In turn, the lateral protrusions  29  support in a non-motorised manner, a relative slide wheel  37  which is attached with its short threaded stem  38  against the outer side of such lateral protrusions  29 , inserting such threaded stem  38  through the corresponding through hole  30 , which is threaded, of the relative lateral protrusion. Lastly, each end of the sliding or mobile carriage  22  thus assembled is supported as will be described, by a corresponding side  39  shaped, for example by die-casting metals or moulding thermoplastic materials, which are identical to each other and are opportunely attached laterally against the box-like structure  18 . 
     The shaped sides  39  are each shaped with a flat outer surface  40  and with an inner surface fitted with two short rectilinear protrusions  41  and  42 , parallel and slightly distanced from each other, made at the relative toothed reels  31  and  32 , in the rear part of the flat bottom  19 . 
     Such rectilinear protrusions  41  and  42  are fitted with a plurality of teeth  43  facing each other, and having a profile and size identical to that of the teeth  44  of both the toothed reels  31  and  32 , and these rectilinear protrusions are moreover distanced from each other by an interval such as to permit the insertion between them of the toothed reels  31  and  32 , so that during this operation the teeth of the latter mesh with the corresponding teeth of said protrusions. 
     Each of the lateral sides  39  is moreover shaped, in the part facing towards the front of the flat bottom  19 , with an elongated through slot  45 , which is inclined upwards in relation to the horizontal plane of said flat bottom, and this slot is sized to slidingly house the relative slide wheel  37  of the lateral protrusion  29 , forming with it an inclined plane for the sliding of said side wheel with a short stroke defined by the corresponding through slot  45 . By means of this arrangement, the sliding or mobile carriage  22  thus assembled can be moved manually in the lateral direction of the box-like structure  18 , from one to the other of the end-stop positions defined by the ends of the through slot  45 , and during this movement the rotation of the toothed reels  31  and  32  in relation to the respective toothed rectilinear protrusions  41  and  42 , which are fixed, is determined, with a consequent rotation of the torsion bar  34  and siding of the slide wheels  37  along the corresponding inclined through slots  45 . Such sliding or mobile carriage  22  can thus be moved from a position in which the torsion bar  34  is positioned next to the rear rim  21  of said box-like structure  18  (see  FIG. 3 ), in the condition in which both slide wheels  37  are housed in the lower end of the relative through slots  45 , and therefore the carriage  22  is lowered and next to the flat bottom  19  of such box-like structure  18 , to a position in which the torsion bar  34  is positioned next to the front rim  20  of said box-like structure  18 , in the condition in which both slide wheels  37  are housed in the upper end of the relative through slots  45 , and therefore the carriage  22  is raised and distanced from the flat bottom  19  of such box-like structure  18 . Inside the front rim  20  of the box-like structure  18  various non-motorised rotating wheels  46  are pivoted, identical and aligned and distanced from each other by the same interval in a longitudinal direction of said box-like structure, and suitable for being housed and rotating inside corresponding rectilinear and longitudinal guide elements (not shown), which are made and attached to the upper part of each door  6  as described below. In addition, in the front side of the elongated profile  23 , facing the front rim  20  of the box-like structure  18 , various non-motorised rotating wheels  47  are pivoted, identical and aligned and distanced from each other by the same interval along such front rim  20 , the wheels of which are pivoted in staggered positions in a longitudinal direction in relation to the positions in which the wheels  46  are pivoted, and are positioned parallel to the wheels  46 . 
     Beside the wheels  47  situated in the end positions, an end stop  48  is respectively placed, composed of a relative disc  49  in soft material such a plastic, rubber etc, which is supported by a relative metal bracket  50  attached under the elongated profile  23 . Each end-stop disc  49  faces towards the opposite inner surface of the front rim  20  of the box-like structure  18  and projects slightly beyond the wheels  47 , as well as being positioned parallel to such inner surface, this way when the sliding or mobile carriage  22  is moved into the rear end-stop position, see  FIG. 3 , all the wheels  47  and all the end stop discs  49  are shifted in a transversal direction to both the aforesaid front rim  20  and to the relative wheels  46 , this way when the sliding or mobile carriage  22  is moved into the forward end-stop position, see  FIG. 11 , all the wheels  47  are aligned and interposed between the wheels  46  and all the end stop discs  49  abut against the inner surface of the front rim  20 , thereby dampening the impact between these component parts. In this last shifted position of the sliding or mobile carriage  22  therefore all the wheels  46  and  47  aligned with each other can be housed and rotate inside the aforesaid rectilinear and longitudinal guide elements attached to the door  6 , for the reason described below. 
     With reference to  FIG. 2  and to  FIG. 4  it may be noted that each door  6  is fitted in the cabinet  5  by means of an elongated weight-bearing profile  51  having the same length as the door and shaped to adapt to and be attached above the same. For this purpose, such elongated weight-bearing profile  51  is square-shaped defining a flat rectilinear front side  52  extending in a vertical direction, and an upper rectilinear horizontal side  53 , bent orthogonally in relation to the front side  52  and having an identical width to the length of the through slots  45  and therefore to the length of the stroke of the sliding or mobile carriage  22  in the transversal direction of said box-like structure  18 . 
     Such horizontal upper side  53  is bent all along its length so as to define a recessed zone  54  facing downwards, the end portion of which is shaped to support a corresponding longitudinal rectilinear profile  55 , constituting a rectilinear and longitudinal guide element, which is attached under said end portion by means of bolts, screws and the like (not shown), inserted through corresponding through holes  56  and  57  of the end portion and of the guide element described. Such longitudinal guide element  55 , moreover, is shaped underneath with a groove  58  all along its length, having a curved profile such as to house only the wheels  47  of the sliding or mobile carriage  22 , when the latter is moved into its rear end-stop position, and to house such wheels  47  and also the wheels  46  of the box-like structure  18 , when this carriage  22  is moved into its forward end-stop position. 
     The installation of the door in position is performed, as seen in  FIG. 2 , by arranging in succession the front side  52  of the weight-bearing profile  51  against the upper part of a cover panel  59 , adaptable and attachable against the rear surface of the door  6 , thence attaching such front side  52  against the panel  59  by means of screws and the like (not shown), inserted through the through holes  60  of said front side and screwed into the aforesaid panel  59 , so that the weight-bearing profile  51  is positioned and attached above the panel  59  in a horizontal arrangement. 
     Subsequently the panel thus fitted is applied and attached suitably against the rear surface of the door  6 , so that the front side  52  of the weight-bearing profile  51  is positioned between the rear surface of the door and the front surface of the panel  59 , and the horizontal side  53  of the weight-bearing profile  51  is facing towards the box-like structure  18  and the sliding or mobile carriage  22 . With this installation arrangement, therefore, the door  6  is supported and moved by the sliding or mobile carriage  22  in the transversal direction of the box-like structure  18 , thanks to the constant engagement of the wheels  47  of said carriage in the groove  58  of the guide element  55 , and in this manner the door  6  can thus be moved by such carriage from the rear end-stop position of the carriage, in which the door is lowered and moved into the closed position, to the front end-stop position of the carriage, in which the door is slightly raised and moved into the open position, positioning itself on the front parallel to the other closed doors, and vice versa. 
       FIG. 1  shows a cabinet  5  with the central doors and right door moved to the closed position, in which such doors are aligned with each other and with the left door moved to the open position. 
     In this condition then, each door  6  is opened by pulling it to the front in the direction A, using the handles  11  and  12 , as far as the front end-stop position of the carriage  22 , then such door is made to slide on the front of the closed doors, as far as the desired position, in the example in the direction B, in that the sliding is permitted by the presence of corresponding identical box-like structures  18  attached to the back of each door  6  of the cabinet  5 , and positioned adjacent and aligned with the remaining box-like structures of such cabinet, so that in this case the guide element  55  of such open door is aligned with the wheels  46  of the box-like structure  18  respectively adjacent, and therefore the sliding of this door is determined by the position and rotation of these wheels  46  in the groove  58  of such guide element  55 . When each door to be opened is moved to the front in the direction A, such door is always kept perfectly parallel and orthogonal by a balancing spring  61 , one end of which winds and unwinds around a pin  62  attached under the elongated profile  23 , and the other end of which is constrained to the arm  63  of a lever  64 , hinged by means of a pin  65  onto the flat bottom  19  of the box-like structure  18 . In the drawing it may be noted that the constraint between the spring  61  and the lever arm  63  takes place by inserting the latter through a through hole  66  of the spring  61 , however this may be achieved in a different manner while remaining within the sphere of protection of the invention. In turn, such arm  63  is provided with a projecting lock  67  at its end to prevent the extraction of said spring  61  from the arm and presents a series of notches  68  positioned close together, to constrain the end of the spring in various positions along the arm, thereby varying the tension of the spring depending on the weight of the door  6  to be balanced each time. This way, during the movement of the door  6  towards its open position, the consequent sliding of the carriage  22  towards the front end-stop position pulls with it the end of the spring  61 , which is preferably of the “constant force” type, suitable for contributing to the balancing of the door, so that such spring  61  is unwound from its pin  62  and exerts against the door  6  a force opposing the direction of movement of such door  6 , which helps to maintain a correct orthogonal and parallel position of the door  6  in all the shifted positions thereof as far as its complete aperture. 
     The same situation also occurs during the movement of the open door  6  towards its dosed position, in such case by means of rewinding of the spring  61  onto its pin  62 , and balancing of the door with an opposing force constant in relation to the closing force of the door, due to the weight of the same on the inclined plane. This guiding and balancing effect exercised on the upper part of the door by the spring  61 , during its opening or closing movement, is also exercised on the lower part of the door by the lower group of component parts of the present support and operating device, shown in FIGS.  2  and  5 - 8 , which is made and functions as described below. 
     As is visible in  FIGS. 2 and 5 , this lower group is substantially composed of a rectilinear longitudinal profile  69 , having the same width as the door  6  and which is applied to the flat lower bottom  10  and attached under the horizontal shelf  17  of the cabinet  5 , at each door, by a shaped bracket  70  which is attached to the lower central part of the door  6 , and by a mobile carriage  71  co-operating with the longitudinal profile  69  and with the shaped bracket  70  as will be described below. In particular, the bracket  70  (see  FIGS. 6 and 7 ) is shaped with a flat vertical side  72 , which connects by a series of steps orthogonally to a flat horizontal side  73 , wherein such vertical side  72  is fitted with various through holes  74 , for the insertion of screws, bolts or the like (not shown) for the attachment of the bracket  70  against the rear surface of the door  6 , above the cover panel  59 , so that the horizontal side  73  is facing towards the cabinet  5 . 
     At the front rim of the horizontal side  73 , two sliding wheels  75  with a vertical axis, identical to each other and mounted free in rotation, are fitted laterally and from below, in an aligned position with each other in a transversal direction of the side  73 , so as to slide in a longitudinal direction along the longitudinal rim  69  of each door  6 , in the manner and for the purpose described below. Moreover, two support plates  76  and  77  identical and symmetrical to each other are applied and attached laterally to the upper surface of the horizontal side  73 , to support a relative wheel  78  and  79  with horizontal axis, identical to each other and suitable for sliding in the transversal direction of the cabinet  5 , in the manner and for the purpose which will be described. 
     The support plates  76  and  77  are shaped in one piece respectively with a flat appendix  80  and  81 , and with a shaped piece  82  and  83 , projecting from the relative lateral rim of the bracket side  73 , in which the appendixes  80  and  81  are attached to the upper surface of such bracket side  73 , while the projecting pieces  82  and  83  are shaped so that their horizontal wheels  78  and  79  are supported freely in rotation and are parallel to each other. 
     In turn, as visible in  FIGS. 5 and 8 , the longitudinal profile  69  is shaped as a double T, defined by a flat and horizontal upper side  84 , and by a flat and horizontal lower side  85 , which is identical and positioned parallel to the aforesaid upper side, as well as joined to it by a vertical and central side  86 . In turn, the upper side  84  of the profile  69  is bent downwards at the front by means of two short flat flaps  87  and  88  facing each other and defining between them a free space which, when the bracket  73  is coupled to such profile  69 , permits the longitudinal sliding of the bracket along this free space, all as will be described. 
     In its central area, the longitudinal profile  69  is fitted with a through aperture  89 , shaped and scaled for the insertion of both the shaped bracket  70  and the mobile carriage  71 , as visible particularly in  FIGS. 5 ,  8 ,  9 ,  10  and  12 . In these figures moreover, it can be seen that the longitudinal profile  69  is attached with its flat upper side  84  and with its flat lower side  85  respectively under the horizontal shelf  17  and over the bottom  10  of the cabinet, and in the figures considered it may be noted that such upper side  84  is attached under the shelf  17  by means of two corresponding flat plates  90 , which are arranged under the rear end portions of the upper side  84  of the profile  69 , using screws, bolts or the like (not shown) which are inserted and screwed into position passing through corresponding through holes  91  and  92  of the plates  90  and of the upper side of the profile  84 , while in turn the lower side  85  of the profile  69  is positioned above the bottom  10  of the cabinet. 
     The lower group thus composed creates the support for the door  6 , firstly applying the bracket  70  against said door as described above, then inserting the horizontal side  73  of the bracket  70  through the through aperture  89  of said profile  69 , so that the vertical wheels  75  and the horizontal wheels  78  and  79  mounted in this bracket side  73  are completely inserted in the free lower space of the cabinet  5 , defined between said horizontal shelf  17  and said bottom  10 , and that such bracket side  73  may co-operate with the mobile carriage  71  as will be described. 
     In this condition then, the inclined step  93  of the bracket side  73  is distanced from the lower rim  94  of the through aperture  89  of the profile  69  (see 4.9), when the door is moved to the closed position, while the mobile carriage  71  is moved to its rear end-stop position, in which it is completely housed inside the aforesaid free space. 
     Such bracket side  73  is then moved outwards, progressively raising itself, gradually as the door is moved outwards towards its open position and vice versa, such bracket side  73  returns progressively from the raised position, when the door is open, to the lowered position gradually as the door is moved to its closed position. 
       FIG. 10  shows the door  6  moved to a partially open (or partially closed, depending on the direction of movement of the door) position, wherein the inclined step  93  is distanced from the through aperture  89  of the profile  69 , while the bracket side  73  is partially extracted from said through aperture, in the condition in which the vertical wheels  75  and the horizontal wheels  78  and  79  of such bracket side  73  are positioned next to but not corresponding to the position of the lower free sliding space of the profile  69 , while the mobile carriage  71  (not shown in the drawing) is distanced from the previous rear end-stop position and moves towards its front end-stop position.  FIG. 12  shows the door  6  moved to the completely open position, in which the bracket side  73  is completely extracted from the through aperture  89  of the profile  69 , in the condition in which the vertical wheels  75  and the horizontal wheels  78  and  79  of such bracket side  73  are placed in a position corresponding to that of the aforesaid free sliding space, in which the vertical wheels  75  are housed inside said free space and distanced from the flat bottom  95  thereof, while the horizontal wheels  78  and  79  are also housed in said free space and rest against the opposite outer surface of the vertical side  86  of the profile  69 , and in turn the mobile carriage  71  is moved into its front end-stop position. In this condition then, such bracket side  73  may be moved in the alternate longitudinal direction of the profile  69 , together with the door  6 , thanks to the guided sliding of said bracket side determined by the sliding of said vertical wheels  75  and horizontal wheels  78  and  79  along the free sliding space of the longitudinal profile  69 , while in turn the mobile carriage  71  remains stationary in its front end stop position. 
     The mobile carriage  71  of the lower group will now be described with particular reference to  FIG. 5   a  which shows said mobile carriage coupled to the longitudinal profile  69 , and to  FIG. 5   b  which shows the mobile carriage  71  with all its component parts separate from each other and detached from the profile  69 . As is visible, the mobile carriage  71  is substantially composed of two lateral sides  96  identical and symmetrical to each other, suitable for being coupled to the through aperture  89  of the elongated profile  69 , and of a central horizontal frame  97  suitable for being coupled between the sides  96 , so as to slide with a limited stroke along the same. The lateral side  96  are shaped with a respective outer portion  98  of a parallelepiped shape, projecting horizontally, and with a respective inner portion  99 , extending in a vertical direction and profiled with a raised portion  100  and with a lowered portion  11 , connected to said raised portion. The relative projecting horizontal portions  98  are scaled so as to adapt and be suitably attached with one end in the corresponding widened area of the through aperture  89 , so that the sides  96  are kept parallel to each other, while the relative inner portions  99  are provided with a corresponding inclined inner groove  103 , which face each other and are made with the same inclination and same length as the through slots  45  of the upper group described above. Such inclined grooves  103  respectively present an open end, facing towards the elongated profile  69 , and a closed opposite end made at the terminal end of each inner portion  99 , and these ends respectively define the front end-stop and the rear end-stop of the central frame  97  of the mobile carriage  71 . To such purpose, the central frame  97  is made in a quadrangular shape defined by two thin sides  104 , parallel to each other and extending in a longitudinal direction of the mobile carriage  71  and by two further sides  105  parallel to each other and joined to the previous sides as well as extending in a transversal direction of the mobile carriage  71 . In the outer part of the longitudinal sides  104  of the frame  97  a pair of non-motorised wheels  106  are respectively pivoted, with a horizontal rotation axis, identical to each other and suitable for being inserted so as to slide in the corresponding inclined grooves  103  of the sides  96 , so as to permit the sliding of the frame  97  in relation to such sides. The assembly of the frame  97  to the sides  96  is completed using a rear horizontal bar  107  and a front horizontal bar  108 , the first of which is attached between two lower notches  109  of the sides  96 , at the rear side of the frame  97  and acts as an abutment for the latter in its rear end-top position, a the second of which is attached between corresponding upper notches  110  of the sides  96 , at the front side of the frame  97  and acts as an abutment for the latter in its front end-stop position. The frame is further provided with a fixed attachment  111  attached in its rear side  105  and to which the end of a longitudinal traction spring  112  couples, the other end of which couples to a rod  113  which is inserted in corresponding cavities of a series of inclined teeth  114 , made projecting from the inner surfaces of the inner portions  99  of the sides  96 , and aligned with each other in a parallel position above the relative inclined groove  103  of said sides. Lastly, the front side  105  of the frame  97  is shaped to be coupled to the end rim  115  of the flat side  73  of the bracket  70 , when the door  6  is moved in relation to the mobile carriage  71  so that these parts come to coincide with each other, and such coupling is obtained in the example shown by a detachable engagement of such rim  115  in a corresponding cavity  116  of the front side of the frame. In this condition then, the door  6  can be moved from the open position to the closed position and vice versa. 
     This way the central frame  97  of the mobile carriage  71  is always moved by the movement of the bracket  70  into the same shifted position of the latter, and during each movement of the bracket  70  it is stressed by the force of the spring  112 , which helps the balancing of the door during the movement thereof from the closed position to the open position and vice versa. This force exercised by the spring  112  (and also by the upper spring  61 ) tends to open the door  6 , in that without these springs  112  and  61  the door would tend to close on account of its weight, thereby reducing the force exerted By the user to open the door  6 . In both conditions however such force of the spring  112  (and of the spring  61 ) assists the shifting movement of the door, which is always kept in its correct parallel and orthogonal position, thanks to the fact that the sliding of the lower part of the door  6  is guided by the sliding of the guide  97  of the mobile carriage  71  along the inclined grooves  103  of the sides  96 , and the sliding of the upper part of the door  6  is guided by the sliding of the wheels  37  in the through slots  45 , and that such sliding always take place in synchrony with each other and in the same sliding positions along the respective sliding paths. The tension of the spring  112  may be varied, depending on the balancing needs, moving said rod  113  each time into a corresponding cavity of the inclined teeth  114 . 
     When the door  6  has been moved to the completely open position (see  FIG. 12 ), wherein the bracket side  73  is aligned with the free sliding space of the profile  69 , as already described above, the door  6  is moved in an alternate longitudinal direction along this profile  69 , detaching the end rim  115  of the bracket side  73  from the cavity  116  of the front side of the frame. 
       FIGS. 9 ,  10  and  12  show the various positions which the door  6  can be moved into in the cabinet incorporating this support and operating device. 
       FIG. 9  shows the door  6  moved into the lowered closed position, in which the mobile carriage  71  is shifted into its rear end-stop position, and is coupled as described with the bracket  70  attached underneath in the door, and in this condition the spring  112  is completely taut keeping the mobile carriage  71  in this rest position, while in turn the door  6  is positioned close to and parallel to the front face of the cabinet and the wheels  37  also of the upper sliding or mobile carriage  22  are moved into the through slots  45  in the same rear end-stop position, which is aligned and coinciding in a vertical direction with the position of the mobile carriage  71 . 
     In this position, moreover, the bracket side  73  is completely inserted in the lower free space of the cabinet, in which the vertical wheels  75  and the horizontal wheels  78  and  79  of such bracket side  73  are shifted in relation to the free sliding space of the profile  69 , so that the door  6  cannot be made to slide in an alternate longitudinal direction. 
       FIG. 10  shows the door  6  moved to a partially open (or partially closed, depending on the direction of movement of the door) position, which has been described above, in which the spring  112  is partially taut (not shown in the drawing), and the frame  97  of the mobile carriage  71  is shifted along said inclined groove  103  in a raised positioned compared to the initial rest position and is still aligned and coinciding in a vertical direction with the position of the wheels  37  of the upper sliding or mobile carriage  22 , with consequent shifting to the front of the door  6 , which is always kept in the correct parallel and orthogonal position. In this shifted position of the door  6 , moreover, the bracket side  73  is still coupled to the mobile carriage  71  and is partially inserted in the lower free space of the cabinet, in which the vertical wheels  75  and the horizontal wheels  78  and  79  of such bracket side  73  are still shifted in relation to the free sliding space of the profile  69 , so that the door  6  as previously cannot be made to slide in an alternate longitudinal direction. Lastly in  FIG. 12  the door  6  is seen moved into the fully open position, already described above, in which the mobile carriage  71  is shifted to the front end-stop position, and is still coupled to the bracket  70 , the side  73  of which is aligned and coinciding with the free sliding space of the profile  69 , in the condition in which the spring  112  is fully distended, and the door  6  can therefore be made to slide in an alternate direction along the profile  69 , using the handles  11  and  12  thereof. 
     In this open position of the door, moreover, the same is still kept in a parallel and orthogonal position, thanks to the fact that the wheels  37  of the upper sliding or mobile carriage  22  are also shifted into the through slots  45  in the same front end-stop position, which is aligned and coinciding in a vertical direction with the position of the mobile carriage  71 . When the door is made to slide along the profile  69  in the desired direction, the end rim  115  of the bracket side  73  is disengaged from the cavity  116  of the front side of the frame, and in this condition the mobile carriage  71  is returned to the rear end-stop position by the weight of the door  6  on the inclined planes of the upper slots  45 , thereby holding the spring  112 , and returning it to its initial rest position in  FIG. 9  in which it is predisposed for subsequent coupling to the bracket side  73 , when the door is once again moved into this position and pressed for its closure. During the longitudinal sliding of the open door, which in the figure appears clearly positioned parallel on the front of a closed door  6 ′ of the cabinet, such door is guided at the top by the sliding of the wheels  46  along the relative longitudinal guide elements  55  and at the bottom by the sliding of the vertical  75  and horizontal wheels  78  and  79  along the longitudinal profile  69  of this door, and is therefore always kept in the correct parallel and orthogonal position. The door  6  may also slide with the same criteria along further longitudinal profiles  69  (not visible in the drawings) which are attached to the bottom of the cabinet in positions coinciding with those of the other doors of the cabinet, and which are positioned adjacent and aligned with the aforesaid longitudinal profile  69  of the door considered.