Device for the compensated guidance and graduated opening of the door of a vertical filing cabinet for suspended plans
FIELD OF THE INVENTION 
     The invention relates to vertical-filing cabinets for suspended plans, particularly to a device for the compensated guidance and graduated opening of the door in predetermined positions. 
     PRIOR ART 
     In known cabinets, the plans are suspended by means of two parallel sets of pins contained in one and the same plane, one fastened to the upper part of the frame of the cabinet and the other fastened at the same level to the vertical sliding door of the said cabinet. 
     A plan to be filed is selected by opening the door to a greater or lesser extent, first to select the position of the plan on the pins, then by continuing to open the door until the spacing between the pins makes it possible to remove or suspend the selected plan. 
     This often results in an accumulation of the weight of the plans on the pins of the door at the moment when the opening of the latter is sufficient to leave a free space between the two sets of pins, making it possible to introduce or remove the selected plan. 
     When the door is being closed, the set of pins which it supports, together with the weight of the suspended plans, must remain strictly parallel and in the same plane as the set of pins fastened to the frame, the guidance of the door assuming importance because of this. 
     In general, the guide device for the opening part is composed of two slide tracks, each comprising four rollers or ball bearings, all four arranged either on the movable part, namely the door, or on the fixed part, namely the cabinet frame: 
     When they are on the fixed part, the movable part carries a guide profile passing on the inside or on the outside of the four rollers; 
     When they are on the movable part, the fixed part carries a guide profile passing on the inside or on the outside of the four rollers. 
     In either case, the guide length is constant and at a minimum, whether in the open position or in the closed position. 
     The plans are manipulated in the known vertical-filing cabinets in two stages: 
     First opening stage 
     Identifying the plan to be extracted and sliding the plans upstream on the pins of the movable part, 
     Second opening stage 
     Forming a passageway between the fixed pins and the movable pins, making it possible to extract the selected plan. 
     In the known cabinets, these two opening stages are carried out by acting manually on a control button or actuating pull, in order to move the slide tracks by releasing them. The finger thus released drops into a nolch corresponding to the first stage. Further action is required to release the slide tracks and move them and so reach the second opening stage. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to improve the accuracy of guidance of the movable part at the most important moment of this function, that is to say at the moment when the pins of the upper part of the door, which support the plans, have to penetrate into the perforations in the suspension bands for the plans supported by the pins fastened to the frame of the cabinet. 
     It also involves doing away with any manual action on the opening mechanism by using means for the automatic detection of at least two predetermined positions of the door in relation to the frame of the cabinet. 
     For this purpose, each guide arm of the movable part is equipped, at its end opposite the door, with at least one roller bearing on the runways of the corresponding slide track fastened to the frame, and each slide track has, on its end nearest the door, at least one track roller controlling the guide arm in its slide track. 
     The guidance of the door is completed by detection means comprising a first movable stop on the guide arm and a second stop fixed to the frame of the cabinet. 
     The first movable stop interacts with an ejector controlled by the movement of the door so as to assume two end positions corresponding to two programmed degrees of opening of the door. 
     For a cabinet loaded to 75% of its capacity, the quality of guidance must be at its highest approximately in mid-travel. Consequently, the guide device described below has one or two rollers fastened to the end of the guide arms of the door and one or two rollers fastened on each side of the frame of the cabinet. 
     In the maximum opening position, with the stop up against the fixed rollers of the frame, there is minimum guidance, but when the cabinet is closed the guidance improves and the guide length is more than doubled in mid-travel. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other advantages will emerge from the description of a preferred embodiment, given by way of non-limiting example, and from the drawing in which: 
     FIG. 1 is a diagram of the device, the door being closed; 
     FIG. 1a is a sectional view, with the door closed; 
     FIG. 1b is a plan view, with the door closed; 
     FIG. 2 is a diagram of the device in the position for selecting the plans; 
     FIG. 2a is a sectional view in the selection position; 
     FIG. 2b is a plan view in the selection position; 
     FIG. 3 is a diagram of the device, the door being open; 
     FIG. 3a is a sectional view, with the door open; 
     FIG. 3b is a plan view, with the door open; 
     FIGS. 4 and 5 show a diagram of the means of guiding the door, comprising two rollers fastened to the free end of the guide arm and two rollers fastened to the frame of the cabinet at the entrance of slide track; 
     FIGS. 4b and 5b show a diagram of the means of guiding the door, comprising a single roller fastened to the free end of the guide arm and having a diameter corresponding to the spacing between the runways of the slide track, and a single roller fastened to the frame of the cabinet of the entrance of the slide track. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The vertical-filing cabinet is composed of a frame 1 which corresponds to the size of the plans and which is closed by a door 2, supported by two guide arms 3 which each move within a C-shaped profile, integral with the frame and serving as a slide track 4 open towards the inside of the frame, along two parallel and superposed runways 40, 41. 
     At least one guide arm carries, on its lower face, a limit stop 9 and, on its side face directed towards the inside of the frame, a journal 5, on which is articulated a movable stop 6 having a recess 16 (FIG. 2). 
     A spring stud 7 penetrating into a hole 8 in the guide arm is fastened to the movable stop 6. 
     A plate 10, fitted after the arm 3 has been inserted into the slide track 4, is fastened to the frame 1; it partially encloses, in the slide track 4, the guide arm equipped with the above-mentioned stops 6 and 9. This plate 10, on its face turned towards the inside of the slide track 4, carries a stop 13, a reactivating finger 14 and a journal 11, on which an ejector 12 is articulated. 
     Each of the guide arms 3 carries, at its free end, either a single roller (FIGS. 4b and 5b), the diameter of which is equal to the distance between the runways 40, 41 of the slide track 4, or a pair of rollers 30, 31, of which the position tangential to these runways 40, 41 ensures strict guidance of the guide arm 3 carrying them. 
     A first roller 15, located in the region of the lower runway 41 of the slide track 4 near the opening in the cabinet and pivoting on a journal 15&#39; fastened to the frame 1, contributes to controlling the guide arm 3 in the slide track 4. 
     A second roller 15&#34; (FIG. 3) can be arranged above the guide arm to reinforce the directional action of the roller 15. 
     The mode of operation of this device is described as follows: 
     When the door 2 is closed (FIGS. 1, 1a and 1b), the movable stop 6 is aligned with the guide arm 3, and the spring stud 7 is engaged in the hole 8 in the arm 3 and keeps the movable stop in alignment; 
     During a first opening stage (FIGS. 2, 2a and 2b), the movable stop 6 comes up against the stop 13 fastened to the plate 10 and thus temporarily limits the opening of the door 2; the ejector 12 pivoting on its journal 11 engages behind a recess 16 of the movable stop 6; 
     When the door is pushed back 2 to 3 centimeters, the movable stop 6 drives the ejector 12 in rotation about its journal 11. During its rotation, the ejector exerts a transverse force on the movable stop 6 and expels the spring stud 7 from the hole 8. The movable stop 6 released in this way assumes a vertical orientation as a result of gravity by pivoting on the journal 5 and adopts a position perpendicular to the guide arm 3; 
     During a second opening stage (FIG. 3, 3a and 3b), the movable stop 6, released and put in a position perpendicular to the guide arm, passes under the stop 13; the maximum opening of the door 2 is obtained when the stop 9 comes up against the roller 15 controlling the guide arm 3. 
     Reactivation and closure 
     When the door 2 is closed, the guide arm 3 drives the movable stop 6 with it. The part 60 of this stop, which is located under the guide arm 3 after the door has been opened (FIG. 3), strikes against the reactivating finger 14 during the movement of closing the door. The movable stop 6 is forced to resume alignment with the guide arm 3, the spring stud 7 automatically resuming its position in the hole 8 of the guide arm. 
     A magnetic catch keeps the door in its closed position, so that in the event of frequent use there is no need to use the key-operated lock.