FR2621440A2 - Device for mounting electronic boards in a frame (rack) having guide tracks (slides) - Google Patents

Abstract

The device according to the main patent is characterised in that the tongue 35A includes a double-thickness flat tab 45A, having an outer wall 36B and an inner wall 37B, provided with the articulation, coming from the inner wall 37B and projecting over it, and with a springy foot 60A and with at least one springy blade 71A, 72A coming from the outer wall 36B and projecting over the inner wall of the tab and going around the outside of the articulation.

Description

Device for mounting electronic cards in a sliding frame.

 The present addition relates to an improvement to the device for mounting the electronic card in a sliding frame, which was the subject of French patent application No. 87 08714 filed on June 22, 1987. It relates more particularly to a method of preferred embodiment of said device meeting the goals of the device according to the main patent application but also leading, in particular, to a significant reduction in its manufacturing cost.

 According to the main patent application, the device for mounting electronic cards in a chassis provided with networks of parallel guide rails comprises at least one pallet which is fixed along a front edge of the chassis at the outlet of a network of guide rails and which pivots in a plane perpendicular to this edge, between a closed position where it abuts against the front face of a card in place in the chassis and an open position where it frees the outlet from the guide slide of said card, and at least one positioning rack to which said pallet is articulated, which is arranged along one of the front edges of the chassis at the outlet of the network of guide slides, set back from the bottom of the latter and which defines different pallet mounting positions spaced apart with a spacing pitch corresponding to that of the network slides, said pallet being provided at one end with a joint tion hooking in the different positions offered along the front edge of the chassis by the positioning rack and, on the outside of this articulation, of an elastic tab for holding in the open or closed position taking support on a sliding surface provided in the front edge of the chassis.

 In this device, the pallet is advantageously provided on the outside of its articulation, with a card extraction stop and with a means of locating a slide. The extraction stop can be formed by a bead placed in relief, at the base and on the outside of the elastic retaining tab, projecting laterally from the latter and obscuring the mouths of guide rails when the pallet is in position. opening, a bevelled notch made through this stop, in the extension of a slide opening out next to the elastic retaining tab leaving a passage for the introduction of an electronic card into the chassis and constituting the slide tracking means.

 The positioning rack advantageously comprises a pivot axis and a rack fixed along a front edge of the chassis at the outlet of the network of card guide slides, set back from the bottoms of the latter.

 The rack which authorizes the mounting, on the pivot axis, of the articulation of a pallet only from place to place, along the front edge of the chassis, according to a spacing pitch corresponding to that of the slideways of guide, may consist of a raised toothing on a sector of the pivot axis and also serve as an end-of-travel stop at the opening for the pallets.

 According to the main patent application, the pallets can be molded in plastic as long as there are no particular constraints in terms of electromagnetic compatibility or electrostatic discharges. Otherwise, they are preferably molded from a metal alloy. They are then particularly advantageous because they remain, in all positions, in close contact with the chassis mass and can also be used, in the closed position, to ensure mass continuity with the front faces of the electronic cards.

 The manufacturing method of the pallet, by pressure molding, leads, due to the production of the mold, to a high unit price of this part and not optimized when this part is produced only in small or medium series.

 The purpose of this addition is to adapt in particular the pallet entering the device according to the main patent application, which must in particular meet the same objectives but, moreover, enabling it to be obtained by a more economical manufacturing process.

 It relates to a device for mounting electronic cards in a chassis provided with parallel guide rails according to the main patent, characterized in that said pallet comprises a double thickness flat tongue, with a wall called the front wall and the wall called the back, substantially provided on an edge said first edge of a projecting articulation on said back wall.

 According to another characteristic, said pallet also comprises an elastic tab projecting from the back wall of the pallet and bypassing said articulation from the outside, said elastic tab and said articulation being from both of the walls. front and back, respectively.

 According to another characteristic, the pallet further comprises at least one elastic strip projecting from the back wall of the pallet, bypassing said articulation from the outside and bordering it laterally, the elastic strip and said articulation being from one and the other side front and back, respectively.

 The elastic tab and the elastic strip come from the same of the front and back walls and the articulation, which is internal to them, extends substantially halfway up them.

 Other characteristics and advantages of the improvement according to the present addition will emerge from the description below of exemplary embodiments illustrated by way of example in the attached drawing. In this drawing - FIG. 1 shows, in partially broken away perspective, a sliding chassis equipped with electronic cards and provided with a card mounting device improved according to the present addition, - FIG. 2 shows the main elements of the device improved card assembly of Figure 1 :: pallet and positioning rack, presented from above, in exploded perspective, in relation to a network of guide rails, - Figure 3 is a vertical sectional view of the lower part of the chassis of FIG. 1, showing the pallet mounted on the positioning rack in the open and closed position, - FIG. 4 is a view given in correspondence with FIG. 2 to show a variant of the device, with a pallet similar to that of FIG. 2 and a positioning rack of simplified embodiment, FIG. 5 is a view in vertical section corresponding to that of FIG. 3, given for the variant according to this figure 4.

 In these figures, the elements identical to those of the device described in the main patent application are designated by the same references, on the other hand those adapted to define the improved device according to the present addition are designated by the references used in the previous device accompanied by 'a capital letter.

 In FIG. 1, the chassis fitted with the improved device according to the present addition essentially appears to conform to that described in the main patent application, the improvement provided is more particularly specified with reference to FIGS. 2, 3, 4 and 5.

 The chassis 10 represented in FIG. 1 is a sliding chassis intended for telecommunications equipment. It comes in the form of a small cassette. It is designed to hang with others along a vertical frame beam and contains a row of electronic cards 11, 12, 13, 14, 15 of different thicknesses, provided with a front face 16.

 It will be noted that, in order not to overload the figures, the printed circuits and the components which these cards contain have not been shown.

 It consists of two metal plates, one lower 17 and the other upper 18, screwed to flanges 19, 20 and to a metal frame 21 supporting hanging lugs 22, 23 on a vertical beam and a card. backplane 24 fitted with connectors 25 for electronic cards.

 The lower and upper plates 17, 18 consist of a thick metal plate of the same shape. On one of their so-called internal faces, intended to be turned towards the inside of the chassis 10, they are hollowed out with a network of parallel grooves serving as guide slides for the electronic cards, with a spacing pitch small, for example equal to one tenth of an inch (2.54mm) very much less than the minimum thickness of an electronic card. On the opposite so-called external face, intended to be turned towards the outside of the chassis 10, they are hollowed out with a network of cylindrical holes 30 placed in staggered rows which, as can be seen in FIG. 3 reach the bottoms 31 of the guide rails but leave their partition wall 32, this to allow circulation of cooling air inside the chassis 10, between the electronic cards, without interrupting the electromagnetic shielding provided by the metallic masses of the plates 17, 18. The front edge of these plates 17, 18, facing the front face of the chassis 10 has two arms lateral 33 supporting at its ends a crenellated bar 34A placed, with a slight spacing in front of the openings of the guide rails, recessed with respect to the bottom 31 of these rails so as not to obstruct the insertion or extraction of the cards electronics in the guide rails.

 This crenellated bar 34A, visible from the front face of the chassis 10, along the edges of the lower and upper plates 17, 18 supporting the networks of guide rails serves as a positioning rack for 35A swivel pallets with a width of the order of 16mm slightly less than the minimum width of an electronic card, that is to say of its front face supposed to be here 17mm. These pivoting pallets 35A placed on the chassis 10 at the upper and lower ends of the front face of each electronic card, blocked in translation and provided with labels on their front 36A as on their back 37A identify the locations of the cards d electronics in the chassis. They also allow, thanks to their particular shape which will be detailed later, to select the pairs of guide rails suitable for electronic cards from those which must remain unused, to facilitate insertion fully electronic cards in the chassis as well as extracting them, and holding them in place. In Figure 1, they are shown in the closed position, pressed against the edges of the front faces of the electronic cards they hold in place, with the exception of two of them shown in the open position while 'They are erased, being set back relative to the bottoms of the guide rails to allow passage to an electronic card half engaged in the chassis.

 Figures 2 and 3 detail the shapes of the crenellated bar 34A and one of the pallets 35A to which it serves as a positioning rack. which fit into the improved device according to this addition.

 The crenellated bar 34A has the general appearance of a cylindrical pivot axis carrying in relief a row of rack teeth 40A covering a cylindrical sector of around 1800 facing the plate 17 shown. These rack teeth 40A come in the extension of the partition walls 32 of the card guide slides and their between teeth 41A in the extension of the slides themselves. At the limit of the cylindrical sector which they occupy, they have relative to the plate concerned here 17, so-called external sides 42A, on the side of the external face of the plate 17, tangent at their birth to the wall of the cylindrical axis and substantially horizontal, and so-called internal sides 43A, on the side of the internal face of the plate 17, slightly inclined at their birth on the tangent to the wall of the cylindrical axis then to a horizontal terminal portion projecting from the wall of the cylindrical axis.

Facing the plate 17, these teeth have their flat edges 44A extending vertically, over part of the thickness of the plate 17. The outer flanks 42A of the rack teeth serve as end-of-travel abutment for the pallets 35A. On the opposite side, the inner flanks also serve as the maximum end-of-travel stop for closing the pallets 35A, which also come slightly before this maximum end-of-travel, abutting against the front faces 16 of the electronic cards when these these are present in place in the chassis.

 A pallet 35A has the general shape of a rigid, rectangular and substantially flat tongue 45A, which carries on the front 36A as on the back 37A label slots, to allow the identification of the electronic card present or absent in the chassis to which is associated the considered pallet. It comes from a strip of metal alloy, such as a steel strip, suitably cut and folded on itself then having undergone a heat treatment (quenching and tempering) giving it sufficient elasticity for its good maintenance on the crenellated bar 34A. This initial steel strip is chosen, for example, 16 mm in width and 1 mm in thickness.

 The tongue 45A is produced by folding this initial strip substantially on itself, in double thickness, and thus has two walls, one known as the front wall 36B and the other known as the back wall 37B.

It has, on one of the small edges of its generally rectangular shape, a large folding loop 46A projecting from the front side 36A, which couples its walls front 36B and back 37B, and which has a gripping window 46B cut out from the front side wall of the loop 46A and forms a gripping tab. A fold 46C, substantially at right angles, makes the transition between the loop 46A and the front wall 36B. This tongue 45A has, on the opposite, substantially on its other small edge, an articulation made up of a pair of hooks 49A and 50A projecting from the back side 37A but below a curved elastic tab 60A flanked by two strips which are also elastic and same profile as it, 71A and 72A. The tab and the blades are clearly more protruding than the pair of hooks 49A and 50A on this back side and bypass them from the outside. Two recesses 36D, substantially at the level of the birth of the strips 71A and 72A are provided on the longitudinal edges, at the end, of the front wall 36B.

 The hooks 49A and 50A come from cutting and folding of one of the ends of the initial steel strip, the adjoining part of which constitutes the back wall 31B of the tongue 35A.

 The tab 60A and the two strips 71A and 72A located on one side and the other of the tab are obtained from cutting and folding from the other end of the initial steel strip, the adjoining part of which constitutes the front wall 36B of the tongue. On the small edge concerned with the tongue 4SA, and regardless of their height on the back side 37A, the tab 60A is central, it is framed by the hooks 49A and 50A which are themselves framed by the two strips 71A and 72A.

 The pallet 35k is deformable under the action of a force exerted on the back wall 37B to move it away from the front wall 36B and can thus be either in the rest state or natural state in which the back wall 37B is very close to the front wall 36B is in a forced state in which the back wall 37B, and therefore the adjoining hooks 49A and 50A, deviates more or less from the front wall 36B.

 The hooks 49A and 50A are placed side by side, being spaced by a multiple of the spacing pitch of the teeth 40A of the crenellated bar 34A. With a radius of curvature substantially equal to that of the toothed sector of the crenellated bar, they can be snapped along this crenelated bar in a multiplicity of positions offset between them by the spacing of the guide rails.

They originate on a folding of the back wall 37B set back from the small edge concerned of the tongue 45A, extend substantially up to mid-height of the tab 60A and the strips 71A and 72A having a concavity turned towards this small edge of the tongue 45A and have their end beaks coming substantially to the right of this small edge while remaining of limited length for snap-fastening facilities on the crenellated bar 34A, in the between-teeth 41A, but sufficient for they always remain trapped in the teeth 41A during the pivoting movement of the pallet.

 When the pallet is mounted on the crenellated bar, the hooks 49A and 50A, then placed in the teeth 41A of the crenelated bar 34A, are located in the extensions of guide rails of the plate concerned here 17 of the chassis; the withdrawal of the crenellated bar 34A with respect to the bottoms of the slides is however sufficient so that they are also set back and do not obstruct the outlets of these slides, one of which opens into the extensions of the hooks 49A and 50A is used for guiding the associated electronic card.

 The curved elastic tab 60A and the two strips 71A and 72A are side by side, defining between them two passages 55A, 56A of width at least equal to that of the hooks which are between the tab and the strips respectively. These passages release and identify above the hooks, the mouths of the guide rails placed in their extension when the pallet is mounted on the crenellated bar and is in the open position. Two lateral notches 55B and 56B, in V, formed in the edge of the tab 60A at the level of these passages improve the clearance of the mouths of the slides.

 The elastic tab 60A and the two strips 71A and 72A which frame it arise following a folding 36C of the front wall 36B, on itself and towards the back wall 37B, over a short length not exceeding 'at the birth ends or feet of the hooks. The end of this folding 36C defines the small edge concerned with the slightly recessed tongue from which the tab and the strips are born, then inside the joint formed by the hooks, substantially at the feet of the latter. and the strips 71A and 72A then bypass the articulation by passing on the other side thereof relative to this small edge of the tongue 45A and then returning in the direction of this small edge while always remaining outside of the joint.

They end in slight advance on the ends of the hooks, the ends of the hooks in place on the crenellated bar and those of the tab and of the strips coming substantially in the same diametrical plane of the bar 34A. They do not meet the row of teeth 40A of the rack, during the movement of the pallet, except in the pallet open position and in the maximum closed position in the absence of an associated electronic card in the chassis. As will be specified below, they contribute on the one hand to the maintenance in place of the hooks 49A and 50A on the crenellated bar and on the other hand to the maintenance in place of the electronic card in the chassis when the pallet is in the closed position.

 We can distinguish several successive parts in the profile of the tab 60A and the two strips 71A and 72A. Independently of the fact that they relate to the tab 60A or the lamellae 71A, 72A, these parts are denoted 66, 62A, 63A, from the birth end, denoted 67 of the leg or the lamella concerned on the fold 36C . These parts are not very curved, they are separated from each other by transitions of different curvatures.

 The end 67 and the adjoining part of the folding 36C provide abutment support on the outer sides 42A of the rack teeth 40A, when the pallet is in the open position.

 The transition zone, noted 68, between the end 67 and the part 66 has a radius of curvature close to that of the non-toothed sector of the crenellated bar, it gives the part 66 a direction inclined substantially at 450 on the tongue 45A and allows the tab and the strips to come off the back of the hooks. This transition zone 68 maintains with hooks the hooks 49A and 50A on the crenellated bar 34A. Indeed, it defines with these hooks a deformable open cylindrical surface which, when the pallet 35k is in the rest state, present in the direction perpendicular to the front wall 36B an inner diameter less than the diameter of the toothed sector of the crenellated bar 34A, for example an internal diameter of 3.5 mm for a diameter of 4 mm of the toothless sector of the crenellated bar. For mounting the pallet on the bar, a force is exerted on the back wall 37B to move it away from the front wall 36B which separates the hooks 49A and 50A from the transition zone 68, that is to say increases the internal diameter and the opening of the cylindrical surface which they delimit and allows the hooking of the hooks on the bar.

 Once the hooks snapped in and the previous force exerted on the back wall removed, the crenellated bar 34A maintains a forced spacing between the hooks 49A and 50A and the transition zone 68 and is therefore pressed between the hooks, which are subjected to a restoring force in the rest state, and the transition zone 68. In FIG. 3, the hooks and the back wall in the rest state when the pallet 35A is not shown have been shown in phantom. mounted on the crenellated bar 34A, opposite their position, in solid lines, when the pallet is mounted on the crenellated bar, with the hooks snapped onto the bar, and put in the open position.

 Part 66 gives abutment abutment against the inclined portion of birth of the internal sides 43A of the teeth 40A of the rack, to define the maximum closing position of the pallet when the associated electronic card is not present in the chassis , however, this maximum closing position remains close to that of closing the pallet when the electronic card is present. The part 62A is slightly inclined relative to the tongue 45A, its transition with the part 66 is protruding towards the small edge of the tongue 45A where the latter has the large folding loop 46A and contributes to the extraction of the electronic card during the pivoting of the pallet from its closed position to that of opening. Part 63A contributes with part 62A and their transition zone, denoted 64A, to keeping the electronic card in place in the chassis when the pallet is in the closed position, the transition 64A then forming a large pressure support on the edge 61 of tray 17.

 It is noted that in the fully open position although the tab 60A and the strips 71A, 72A are no longer in contact with the edge of the plate 17, the electrical continuity between the plate 17 and the pallet is sufficiently ensured by the crenellated bar 34 on which the hooks 49A and 50A of the joint are strongly tightened.

 Advantageously, in the case where the pallet is metallic and the front face of the electronic card is part of the sixth side of a metallic shield, it is possible, as illustrated, to cut from the back wall 37B of the tab 45A a tab 75A, which makes it possible to press on an elastic strip 76 cut opposite the edge of the front faces of electronic cards in order to guarantee permanent contact between the front face 16 of an electronic card in place in the chassis and the pallet in the closed position which holds it in place, and to achieve mass continuity.

 The pairs of pallets are fitted onto the two crenellated bars of the lower and upper plates of the chassis after having determined, as described in the main patent, the slices which can occupy in the chassis the electronic cards and the slides which they then use .

 In FIGS. 4 and 5 there is illustrated, with pallets very similar to those which have just been described above, the variant embodiment suggested in the main patent, according to which the rack teeth of the positioning rack are arranged not not on the bar where the pallet joints fit but on the edge of the tray placed opposite this bar.

 In these two figures, the differences have simply been clarified with regard to the preceding figures 2 and 3. Identical elements are identified by the references used to designate them in Figures 2 and 3.

 In these FIGS. 4 and 5, the pallet 35B, very slightly adapted as will be explained below, is no longer snapped onto a crenellated bar but onto a smooth bar 34B and is kept positioned, along the length of this smooth bar, by teeth 40B of a rack provided on the edge 61A of the plate here 1FA, placed facing this bar, this edge therefore being serrated or crenellated.

 Two lateral flanges 33A are held at the front of the plate 17A, for holding the smooth bar 34, with between them a base 33B, of small thickness compared to that of the plate, on the side of its external face which it extends along the length of the smooth bar 34B.

 The rack teeth 40B are of arrangements similar to those of the partition walls 32 provided on the internal face.

The rack teeth 40B of general appearance transverse to the partition walls 32 of the guide rails come in their extension, remaining slightly recessed on the level of the bottoms 31. Their between-teeth 41B are in the extension of the rails themselves . These teeth are of generally rectangular shape which can have an inclined portion on their inner flank, facing the bar, which is comparable to that of the inner flanks of the previous teeth. The crenellated edge 61A of the plate 17A is spaced from the bar, like the smooth edge of the plate 17 in the case of FIGS. 2 and 3.

 The pallet 35B is identical to the aforementioned pallet 35A except for its two elastic strips designated by 71B and 72B which frame the internal hooks 49A and 50A and the central elastic tab 60A. These two strips are slightly longer than the previous ones. These strips 71B and 72B have the intermediate part of their profile denoted 62B and the terminal part denoted 63B which are made slightly longer than the corresponding intermediate part 62A and the end part 63A of the elastic tab 60A, and which therefore make them strips 71B, 72B projecting from the outside of the tab 60A. In addition, these strips 71B and 72B are offset towards the longitudinal edges of the tongue 45A while coming to form between them and the elastic tab 60A two spaces or passages, denoted 55B and 56B, enlarged by as much while the lateral recesses 36E are reduced by the same amount in depth, compared with the preceding 36D. This offset corresponds substantially to the width of a partition 32 or a rack tooth 40B.

 These slight adaptations of the pallet allow the strips 71B and 72B to engage in the teeth 41B of the notched edge 61A of the plate and to remain engaged there, more or less at the bottom of these teeth for the positions d opening and closing of the pallet and in any intermediate position, to ensure the positioning of the pallet along the smooth bar 34B.

From the actuation of the pallet from its open position to its closed position, the elastic tab rubs in pressure on the notched edge 61A of the plate 17A, at the end of the teeth as it had just rubbed against the smooth edge of the plate 17.

 The base 33B constitutes in this assembly a stop for supporting the pallet in its open position.

 The mounting and positioning of the pallets in front of the lower and upper plates are done as above after determining the slices which the electronic cards and the slides they use can occupy in the chassis. Each slide used is an extension of one of the articulation hooks on a pallet; the two strips 71B and 72B of each pallet are engaged in the between-teeth which are in the extensions of the two slides directly framing those located in the extensions of the two hooks of this pallet.

 The two embodiments described, according to FIGS. 2 and 3 and FIGS. 4 and 5, have the advantage of using a pallet obtained by successive cuts and folds of a strip, using tools to be followed, and then subjected to a thermal quenching and tempering operation, leading to a reduced manufacturing price compared to the embodiment described in the main patent application. This pallet also allows to benefit from a holding on the articulation bar improved by the tightening of its articulation hooks on the bar.

 In addition, the last variant according to Figures 4 and 5 further contributes to reducing the cost of producing the device. The rack teeth formed on the edge of the tray are easy to obtain from molding the tray while the hinge bar becomes fully smooth.

 Of course, the adaptations resulting from these illustrated embodiments, which are within the reach of those skilled in the art, must be understood within the scope of the present invention.

Claims (15)

1 / Device for mounting electronic cards (11, 12, 13) in a chassis (10) provided with parallel guide rails, with at least one pallet and at least one positioning rack according to claim 1 of the main patent , characterized in that the said pallet (35A) comprises a flat tongue (45A) double thickness, with a wall called the front (36B) and the wall called the back (37B) / provided substantially on one edge called the first edge of a joint (49A and 50A) projecting from said back wall (37B). 2 / Device according to claim 1, characterized in that said articulation is adjacent to said back wall (37B) on which it originates on a fold, substantially at right angles, set back from said first edge of the tongue. 3 / Device according to one of claims 1 and 2, characterized in that said pallet (35A) further comprises an elastic tab (60A) also projecting on said back wall (37B) of the pallet and bypassing said articulation (49A and 50A) from the outside of this joint. 4 / Device according to claim 3, characterized in that said elastic tab (60A) is adjacent to said front wall (36B) on which it originates substantially on a fold (36C) on itself of the front wall, defining said first edge of the tongue. 5 / Device according to one of claims 1 to 4, characterized in that said pallet further comprises at least one elastic strip (71A, 71B, 72A, 72B) also projecting on said back wall (37B) of the pallet and bypassing said articulation (49A, 50B), from the outside of said articulation. 6 / Device according to claim 5, characterized in that said elastic strip (71A, 71B, 72A, 72B) is adjacent to the front wall (36B) on which it originates substantially on a fold (36C) of the front wall on itself, defining said first edge of the tongue. 7 / Device according to one of claims 1 to 6, characterized in that said front and back walls (36B, 37B) are coupled to each other by a loop (46A) on the edge opposite to said first edge having the joint (49A, 50A), projecting from the front wall (36B) and forming a gripping tab. 8 / Device according to one of claims 3 and 4, characterized in that said articulation (49A and 50A) laterally borders said elastic tab (60A) by releasing and locating on either side of said tab the mouths of slideways card guide in the extension of said articulation, when the pallet is in place on the chassis. 9 / Device according to one of claims 5 and 6, characterized in that said elastic strip (71A, 71B, 72A, 72B) laterally borders said joint (49A and 50A) by releasing and locating the mouth of a slide of card guide in the extension of the joint when the pallet is in place on the chassis. 10 / Device according to claim 9, characterized in that the positioning rack comprises a crenellated bar (34A) defining the axis of articulation of pallets, fixed along a front edge of a plate (17, 18) of the chassis, at the end of a network of card guide slides, said crenellated bar being set back with respect to the bottoms (31) of the slides and having a row of rack teeth (40A) on a sector substantially of 1800 facing to the edge (61) of said tray. 11 / Apparatus according to claim 10, characterized in that said rack teeth (40A) are limited by so-called external sides (42A) turned towards the outside of the chassis, substantially parallel to said plate and tangent to the wall of the axis d 'articulation, and internal opposite sides (43k) inclined at their birth on the wall of the axis of articulation on the tangent to this wall then protruding and parallel to the tangent in their opposite end part. 12 / Apparatus according to claim 9, characterized in that the positioning rack comprises a smooth bar (34B) defining the axis of articulation of pallets, fixed along a front edge of a plate (11A) of the chassis , at the outlet of a network of card slides, set back on the front of said tray and relative to the bottoms (31) of the slides and a row of rack teeth (40B) provided on the then crenellated edge (61A) of said plate (17A) receiving in one of their teeth (41B) said elastic strip (71B, 72B) for positioning along said smooth bar (34B) said pallet simply articulated on the smooth bar (34B). 13 / Apparatus according to claim 12, characterized in that the teeth of the rack (40B) of the crenellated edge (61A) of the plate are in step with the partition walls (32) of the slides, with their between-teeth (41B) in the extensions of the mouths of the slides. 14 / Device according to claim 13, characterized in that it comprises, along said smooth bar (34B) and the crenellated edge (61A) of the plate, in the extension of the face of the plate turned towards the outside of the chassis, a base (33B) forming a stop for said pallet in the open position. 15 / Device according to claim 4, characterized in that the positioning rack comprises a bar (34A, 34B) defining the axis of articulation of pallets and a row of rack teeth (40A, 40B) fixed along a front edge of the chassis, at the outlet of a network of card guide slides, said bar being spaced from the front edge of the chassis and recessed with respect to the bottoms (31) of the slides, and in that said articulation (49A, 50A) of the pallet is formed by at least one articulation hook, adjoining said back wall (37B) on which it originates on a fold, substantially at right angles, set back from said first edge of the tongue, said hook d articulation being of internal diameter substantially equal to the diameter of said bar (34A, 34B) defining the axis of articulation of the pallets and delimiting with said elastic tab, on a portion (68) of this curved tab and with concavity turned towards that of said hook, a surfa this open and deformable cylindrical, having in the direction perpendicular to the front wall (36B) an internal diameter / which in the absence of stress exerted on said pallet, is less than the diameter of said bar (34A, 34B) and which, under the action of a force exerted on the back wall (37B) of the pallet to move it away from the front wall (36B), increases to allow the latching of said hook on the bar (34A, 34B).