FR2598187A1 - Locking system for assembling two perpendicular plates - Google Patents

Abstract

Locking system for an assembly of two perpendicular plates, formed from a slit and an insert. The tab comprises a protuberance which is elastically deformed during assembly by passing through an extension of the slit having a suitable shape and which, by returning to its initial position, ensures the locking.

Description

The present invention relates to a locking technique, without bonding or stapling, of an assembly, based on corrugated cardboard, or any other similar product, such as "AKILUX" (FIG. 1), which is a polypropylene profilyextruded, whose structure is similar to that of a corrugated board, or such as compact cartons.

The cardboard industry has been dominated for years by the manufacture of cases intended for grouping transport.

These cases are of the "American case" type, three-piece case with flap or lid. To make crates, we start with a cardboard plate that we cut first, then fold and assemble. The assembly of these boxes, their closure, uses either gluing, or wrapping paper or adhesive plastic film, or stapling. More and more, with the increase in rates, we tried to remove, whenever possible, the assembly accessories which are the cause of the complication of the chains and we replaced them with special cutouts, adapted to each problem, and making the best use of the anisotropy of the mechanical characteristics of the material used. These cut-outs allow, during assembly of the box, to lock assemblies without using either staples, glue, adhesive paper or adhesive film.

In general, these solutions are intended for packaging, and efficiency has been sought before aesthetics, and often the assemblies reveal unsightly openings.

At the same time, the use of an extruded polypropylene profile has made it almost essential to use cut-out assemblies. In fact, bonding is difficult and the use of staples or adhesive tape must be limited to what is strictly necessary, because it is an expensive material which is used for applications other than packaging, such as display stands, storage lockers, school bags ...

The product is delivered flat, unassembled, and, since it is the end user who does the assembly, he must be able to do it without using accessories. We can, of course, do the assembly in the factory, but, at that time, we create an expensive and fra gille volume to transport, since it is empty. You can also mount accessories such as snap fasteners in the factory, which are then easy to assemble, unfortunately, this is a crusty operation.

The present invention provides an assembly method comprising a locking protruding directly from the cutting of the plate, without it being necessary to do, afterwards, any recovery whatsoever.

FIG. 1 represents a plate fragment of material type "A
KILUX ".

2 shows a side view of a plate bent under the action of a linear load (36).

FIG. 3 represents the side view of a plate after buckling under the action of a linear load; in dotted lines, we have represented the profile of the plate just before its buckling, with a critical bending radius.

Figure 4 shows the assembly parts consisting of a tongue (3) and a slot (19) according to the invention, with assembly by translation.

Figure 5 shows a detail of via slot (19) and its extension (16).

Figure 6 shows an extreme case of extension (16) of the slot (19).

FIG. 7 shows a double locking system according to the invention.

Figure 8 shows' 4Iouble verroutllage with a double central guide according to the invention.

Figure 9 shows a lock according to the invention with assembly by rotation.

Figure 10 shows the deformation of the ekgrowth (43) during the assembly phase.

The plate (Fig. 1) is defined by one or more layers of rigid materials, compact or cellular, limited by two parallel planes (41) and (42) whose distance representing its thickness (40) is of the order from 1% to% o of its largest dimension.

As we said before, the cardboard, 1 "AKILUX", compact cardboard or rigid PVC sheet, meet this criterion, but the list of simple or composite materials that can be used is not exhaustive .

The plate taken into consideration is sufficiently rigid that it can deform by elasticity up to a certain threshold beyond which there is permanent deformation.

 Ai we place the plate (35), (Fig. 2) on two supports (33) and (34) parallel, and apply a progressive load perpendicular to the plane of the plate and distributed along a parallel line (36) like supports, one obtains first a deflection of the plate which takes the form of a cylinder whose generatrices are parallel to the line of cherge. We consider the mean radius of curvature (37) of the bent plate at the point of application of the load (36): it has a value which decreases when the load increases, then, at a given moment, there is buckling of the plate. We will call critical radius of flexion (38), (Fig. 3) in a given direction, in this case that of the load line (36), the minimum radius below which buckling (39) of the plate.

We consider on the one hand, (Fig. 4), a plate (1) of thickness "el", in which we want to anchor, perpendicularly another plate (2), of thickness "e2" provided with a tongue anchor (3). This tongue has a substantially rectangular shape comprising in particular a rectilinear lateral cutout (4) with a length of the order of 10 times the thickness "el". the other lateral cutout has a particular profile comprising a protuberance (43), (FIG. 4), a ramp which is slightly inclined on the order of 25 to 35 X relative to the cutout (4), a ramp (6) reversed by relative to the ramp (5) and strongly inclined greater than 150% compared to the cutout (4); finally, a cutout (7), parallel to (4) to complete the tongue (3) and connect it to the plate (2)
The width (8) of the tongue (3), at its end is less than or equal to the width (g) between the cutouts (7) and (4). The length (13) of the segment (7) is chosen to be greater or equal to rre 1 rice
In the plate (1), we make, on the one hand, a slot (19) of width (11) equal to "e2" and of length (12) equal to the width (9) of the tongue. This slot is intended to receive the tongue (3). The end (14) of the slot will serve as a guide for the straight cutting (4). On the other hand, the end (15) does not allow the passage of the ramp (5). Provision is therefore made to extend the end (15) by a slot (16) as shown in FIG. 5. According to one embodiment, the slot (16) is formed of concentric circular rocks (17) and (18), distant from "e2", whose mean radius is greater than the critical radius of the plate C2), in a direction parallel to the cut (4); the two circles (17) and (18) have their center arranged so that they are respectively tangent to each edge of the slot (19) and that the point of contact (20) of the circles is at such a distance from. edge (15) that the circle (18) cuts it approximately in the middle.

When we present perpendicular to the plane (1) (Fig. 10) the tongue (3) faces the slot (19), the cutout (4) is applied to the edge (14) which constitutes a guide, the ramp (5 ) is positioned at the height of the end (15). If we exercise
tab a pressure perpendicular to the plane (1) on the / the edge (15) bends and the ramp (5) engages in the slot (16); and the slight slope of the ramp (5) plays a multiplier role to cause the progressive weakening of the protuberance which it forms. As the tongue sinks, the deformation increases without there buckling, since one does not reach the critical radius (38). At the end (21) of the ramp (5) one is practically in contact with the end (22) of the slot (16). THEN, when we approach the ramp (6), the protuberance by elasticity quickly comes back to its initial position, the edge (15) then coming into contact with the cutout (7). At this point, the system is locked; when you want to do the opposite path, you no longer have the multiplier effect due to the slope, and you get a retaining effect. In practice, the slot (16) may be less than "e2" insofar as the plate (1) has sufficient flexibility to allow the passage of the tongue (.3) by bending of the edges. The slit (16) can even be reduced to a simple cutting line (23), - (Fig. 6), starting in the anal end (15), its end (24) being conssupérieur a tait line cutting length / e2 perpendicular to t23). The interest of the system is. only when the slot (23) is.

closed after allowing the ramps (5) and (6) to pass, a continuous surface is received. Likewise, the slot (16) does not necessarily consist of tangent arcs of circle, insofar as the edges of the slot (19), the end (15) and the edges of (16) are capable of deform more or less depending on the pressures exerted by the tongue (3) so that the latter can bend in the area of the ramps without the radii of curvature ever passing below the critical radii (38)
We have described tongue (3) penetrating into the slot following a rectilinear movement perpendicular to the plane (1).

We can notice that there is no restraint on the side (14) and that it could be interesting, for certain applications, to have the same restraint, as shown in figure 7. We will note, however, that, yes. the tongue is badly guided, there is a risk of having diffi
cultured to push the tongue, which will go awry. I1
it is preferable, in some cases, to have a double guide can.

 tral, as shown in Figure 8.

We have studied so far the case of a tongue that we
pushes in a straight line. One can imagine that the lan
watch enters the slot (19) along a circu
laire whose axis of rotation (30) is perpendicular to the axis
of the slot (19), (Fig. 9).

The guide cutout (25) is an arc centered in the center
of rotation (30), the ramp t26) is a fraction of a spiral
peeping from the center of rotation (30) while the ramp (27)
quickly approaches it until the cut-out (28) is mended, which
is an arc (31) centered at (30), the point (29) end
of the ramp (26) being itself located inside or on the
circle (31).

In general, we will admit (Fig. 4), for the tongue, a
total length (10) at the top of the protrusion greater than the
width (9) worth approximately 2a4 "e2".

It is the same in the case of a rotational embedding; the top (32) (Fig. 9) of the ramp (26) is also at a distance of
2 to 4 "e2" of the circular arc (31),

Claims (3)

 1 - Assembly of two plates perpendicular to one another  tre, characterized in that the plate (1) has a rec slot  tilinear (19) extended in one of its ends (15) by a slot (16) having a different general direction, of length  equal to or greater than the width of the projection (43), in that  that the plate (2) has a tongue (3) with one of the sides  has a protuberance (43) formed by a ramp (5) at low  slope and a ramp (6) of directIon reverse with steep slope,  so that when the tongue (3) is pushed into  the slit (19) of the protrusion (43) is graceful in guiding the end  mite (14) on the cutout (4) is first bent in its area  elastic by action of the slot 16) on the ramp (5) which plays  a multiplier effect, then released during the passage  of the ramp (6) which constitutes, at the end of insertion of the lan  look out for, retaining the assembly, in that the profile of the  slot (16) is determined according to the rigidities of each of the  plates so that when the protrusion (43) passes through  the slot, the critical deflection radii (38) are not  never reached.  2 - Assembly according to the preceding claim, characterized in that the ramp (5) has a slope of 25 to 35 X, the ramp (.6) has  an inverse slope greater than 150 X compared to the cutting of  guide C4), in that the protrusion (43) has a height of the gold  from 2 to 4 times the thickness "e2" of the tongue (3), in that the end (24) of the slot (23) has a greater length  to "e211.  3 - Assembly according to any one of the preceding claims, characterized in that the tongue has two protrusions  sances (43) and that the slot C19) has two slots (16) pro  along the ends (14) and (15).