FR3074702A1 - FOLDING SIEVES - Google Patents

Abstract

Sieve consisting of a tubular body forming a receptacle whose bottom is constituted by a mesh (4). The tubular body (1) comprises a rigid lower ring (10) with the bottom (3) provided with the mesh (4), a rigid upper ring (30), an intermediate ring (20) connecting the lower ring (10) to the upper ring (30) along a lower junction line (11), peripheral, and a peripheral upper junction line (31). The intermediate ring (20) defines two peripheral hinge lines (21, 22) and forms a unrolling bellows. The sieve (100) folds by depressing the lower ring (10) into the upper ring (30) and unwinding the ring gear (20) in the gap between the lower ring (10) and the upper ring (30) .

Description

The present invention relates to a sieve composed of a tubular body forming a receptacle, the bottom of which is constituted by a mesh fabric.

State of the art

Such known sieves, in particular as mason sieves for sifting sand, are also used in other fields such as baking or cooking to sift pulverulent products, for example to separate lumps of flour or of a powder.

A folding screen is already known according to document FR 984028. This folding screen used in construction is composed of a frame in which is integrated a mesh fabric forming the screen itself. This chassis is carried by a support formed by folding feet. The product to be screened is poured over the screen, slightly inclined so that the products to be retained remain on the screen, the screened products passing through it.

This large sieve, which is used to screen sand loaded with pebbles on a construction site, has the advantage of being less cumbersome for transport when the feet are folded up.

But such a static sieve is not intended to be hand-held to screen a small volume of powdery products.

In summary, it is not a sieve formed of a tubular body, for example of plastic, and the bottom of which is constituted by a mesh canvas.

Purpose of the invention

The present invention aims to develop a sieve of the type defined above formed of a tubular body, for example of plastic material, constituting the receptacle for receiving the product to be screened with a bottom consisting of a mesh, and which would be less bulky to package, store and distribute than known sieves.

Presentation and advantages of the invention

To this end, the invention relates to a sieve composed of a tubular body forming a receptacle, the bottom of which is constituted by a mesh fabric. The tubular body includes:

a rigid lower crown with the bottom provided with the mesh, a rigid upper crown, an intermediate crown connecting the lower crown to the upper crown along a lower, peripheral junction line, and an upper, peripheral junction line, the intermediate crown defining two peripheral articulation lines and forming an unrolling bellows, * the sieve folding by pressing the lower crown into the upper crown and unwinding of the intermediate crown in the interval between the lower crown and the upper crown.

This sieve has the advantage of being able to fold up to take an extremely compact shape, advantageous for packaging after its manufacture, transport and storage.

For the user, this compactness is also advantageous for transport and storage, whether it is a sieve used in construction and having a relatively large diameter in the case of a sieve of circular section or even smaller dimension but nevertheless cumbersome in the deployed state in the case of a household use like sieve with flour or other pulverulent product.

According to another advantageous characteristic, the junction line of the lower and upper rings is distinct from the articulation line of the intermediate crown and the interval between the junction lines and the articulation lines forms flexible marginal bands.

This type of sieve structure is in particular that of sieve, the lower, intermediate and upper rings of which are produced separately so that they can then be assembled and secured.

According to another advantageous characteristic, the lower and upper rings are of frustoconical shape.

According to another advantageous characteristic, the lower and upper rings are of cylindrical shape.

The section of the crowns is advantageously circular or oval or polygonal.

According to an advantageous characteristic, the lower, intermediate and upper rings are produced in one piece by injection from several materials.

drawings

The present invention will be described below in more detail with the aid of examples of sieves represented in the appended drawings in which:

Figure 1 is a partial sectional view of a mason sieve according to the invention, in the deployed position, Figure 2 is a sectional view corresponding to that of Figure 1 showing the sieve in the folded position, Figure 3 is an explanatory diagram of a screen according to the invention, FIG. 4 shows another form of screen section according to the invention.

Description of embodiments of the invention

According to FIG. 1, the screen 100 according to the invention is formed of a collapsible tubular body 1 provided with an upper edge 2, for gripping and in the lower part, with a bottom 3 with a meshed canvas 4 and with a lower edge 5.

The tubular body 1 is of circular, oval or polygonal section and of frustoconical, cylindrical shape or a combination of these two shapes.

The cylindrical body 1 is composed of a rigid lower crown 10, provided with the mesh fabric 4 and of a rigid upper crown 30 as well as an intermediate crown 20 connecting the lower crown 10 to the upper crown 30.

The intermediate ring 20 is connected to the lower ring 10 by a low junction line 11, peripheral and to the upper ring 30 by a high junction line 31, peripheral.

The junction lines 11, 31 are immaterial if the tubular body 1 is made in one piece, for example by injection of a single material or of several materials; these junction lines are real if the tubular body 1 is composed by the assembly of the crowns 10, 20, 30 produced separately and then assembled. The junction lines are materialized by the upper edge of the lower ring 10 and the lower edge of the upper ring 30. The edges have the same references 11, 31 as the corresponding junction lines.

The intermediate crown 20 forming an unwinding bellows between the lower crown 10 and the upper crown 30 is made of a relatively flexible material, compatible with the deformation necessary for the unwinding movement both in compression and in deployment as will be explained below. The intermediate ring 20 has good tensile strength since it transmits the weight of the load to be screened, placed in the receptacle mainly in the lower ring 10.

The intermediate crown 20 forms two articulation lines 21, 22, peripheral, coincident with the junction lines 11, 21 or separate from these.

In the latter case, there remains a lower marginal peripheral strip 24, of a certain flexibility between the lower junction line 11 and the lower articulation line 21; similarly, there remains an upper peripheral peripheral band 25 between the upper articulation line 22 and the upper junction line 31.

Thus, the rigidity zone defined by the upper edge 11 of the lower crown 10 and the rigidity zone defined by the lower edge 31 of the upper crown 30 can deform to absorb the thickness of the intermediate crown 20 during the movement of unwinding of the latter, when the lower crown 10 is inserted into the upper crown 30 (or vice versa depending on the point of view) to arrive at the compact, folded shape, shown in FIG. 2 or to deploy from this compact shape.

The structure of the screen 100 according to the invention will be described in more detail with the aid of FIG. 3 which is a sectional diagram of such a screen 100 in the deployed position and in the compact folded position. Figure 3 shows schematically the lower ring 10, the intermediate ring 20 and the upper ring 30 by simple lines. It locates the junction lines 11, 31 and the articulation lines 21, 22.

For a more general presentation, lines 11, 31; 21, 22 are not confused two by two in this drawing.

The folding movement by the passage of the upper ring 30 on the lower ring 10 (or vice versa) requires that the high articulation line 22 can pass around the low articulation line 21 and that these two lines 21, 22 are sufficiently spaced apart to allow, during this unwinding movement, the passage between them of the intermediate zone 23 of the intermediate ring 20 comprised between the two articulation lines 21, 22.

The diagram shows in projection the difference Δ between the low articulation line 21 and the high articulation line 22 which are peripheral lines, circular or oval, even polygonal, according to the shape of the section of the low rigid rings 10 and high 30. In the case of circular sections, this difference Δ corresponds to the difference of the radius of the two sections.

The condition of spacing Δ between the two articulation lines 21, 22 corresponds substantially to the thickness of the intermediate zone 23. However, insofar as the articulation lines 21, 22 do not coincide with the junction lines respective 11, 31, there is the low marginal band 24 and the high marginal band 25 which have a certain elasticity like the rest of the intermediate crown 20. The difference to be taken into account to allow folding is the difference between the rigid parts, that is to say very schematically the lower junction lines 11 and upper 31, which makes it possible to reduce the interval of these peripheral junction lines.

In other words, if the marginal bands 24, 25 are rigid, the difference to be taken into account for the thickness of the zone 23 is the difference between the peripheral articulation lines 21, 22 whereas if the bands 24, 25 are flexible and can be retracted by elastic compression or extension, the junction lines 11, 31 then considered to be rigid (not extensible) are to be taken into account, their distance D having to allow the passage of the intermediate zone 23 into its unwinding movement. The folded screen will be even more compact.

Figure 3 also highlights the height of zones 12, 23 and 32:

the height hl of the lower zone 12 is between the lower edge 5 of the screen 100 and the low articulation line 21, the height h2 of the intermediate zone 23 is that already defined above, between the low articulation line 21 and the high articulation line 22, the height h3 of the upper zone 32 is that between the high articulation line 22 and the upper edge 2.

The total height H of the sieve 100 deployed is:

H = hl + h2 + h3.

The total height Ho of the compressed screen 100 is reduced by 2-h2 compared to the deployed height H so that the compressed height is equal to:

Ho = hl + h2 + h3-2-h2, i.e. Ho = hl + h3-h2.

In the case of the example of FIGS. 1 and 2, being a subdivision of the height into three substantially equal zones 12, 23, 32, except that the upper edge 2 is the protrusion, the compressed height Ho is therefore Ho = hl excluding overshoot of the edge 2. In other words, the deployed height is then divided by three in this exemplary embodiment.

In the example of FIGS. 1 and 2, the peripheral articulation lines 21, 22 are produced by reductions in thickness of the intermediate ring 20 to fix the position of these articulation lines 21, 22 and prevent the forces folding do not affect the joining lines 11, 31 at the edges of the crowns 10, 30 which are areas of assembly of the crowns 10, 20, 30.

The sieve 100 can be produced with crowns 10, 20, 30 injected in several phases with rigid plastics for the crowns 10, 30 and less rigid, or even flexible, for the intermediate crown 20.

According to another embodiment, the crowns 10, 20, 30 are produced separately in suitable materials and they are then assembled and joined, for example by welding.

The result of this process is a folding screen 100, 100a in a very compact form, advantageous for packaging, storage and transport. In the case of infrequent use, this advantage of compactness in the folded state is advantageous for storage.

Figure 4 is a schematic sectional view of a variant of screen 100a whose components are similar to those described above and bear the same reference numerals supplemented with the suffix "a". Some components already described above will not be described again.

The only difference between the two embodiments is the cylindrical shape in FIG. 4 and the frustoconical shape for the previous embodiment. Thus, the lower ring 10a and the upper ring 30a are cylindrical in shape and their radiation difference in the case of a circular section is sufficient for the passage of the intermediate ring 20a by its unwinding movement during compression or deployment. of the two rings 10a, 30a of the sieve 100a. This separation of the sections of the articulation lines 11a, 31a combined here with the joining lines 11a, 31a for the purpose of simplification, imposes a frustoconical shape for the intermediate crown 20a.

We can also consider other variants of crown shapes 10, 30 and the crown 20 which connects them. We can thus consider, for example, forms of revolution having generators which are not straight but curved, wavy or formed of straight segments, for example to increase the rigidity of the crowns 10, 30 without increasing the mass of material necessary for their manufacture.

Whatever the shapes of the generatrices of the crowns constituted by surfaces of revolution, the dimensions of the lines of junction or articulation of the crowns must allow the passage of one over the other with an interval receiving the intermediate crown in its unwinding movements.

NOMENCLATURE

100

Collapsible screen Tubular body Upper edge Bottom

Mesh canvas

Bottom edge

Lower crown

Upper edge / lower peripheral junction line

Lower area

Intermediate crown

Low articulation line

High articulation line

Intermediate zone

Lower marginal band

Upper marginal band

Upper crown

Bottom edge / top peripheral junction line

Upper area

Δ Cross-section difference between the low articulation line 21 and the high articulation line 22

D Cross-section difference between the lower junction line 11 and the upper junction line 31

H Height of the unfolded sieve Ho Height of the compressed sieve h 1 Height of the lower zone h2 Height of the intermediate zone h3 Height of the upper zone

Claims (6)

1 °) Folding sieve composed of a tubular body forming a receptacle, the bottom of which is constituted by a mesh canvas, sieve characterized in that the tubular body comprises: a rigid lower crown (10) with the bottom (3) provided with the mesh fabric (4), a rigid upper crown (30), an intermediate crown (20) connecting the lower crown (10) to the upper crown (30) along a lower junction line (11), peripheral, and an upper junction line (31), peripheral, the intermediate ring (20) defining two peripheral articulation lines (21, 22) and forming an unrolling bellows, * the sieve (100) being folded back by depressing the lower ring (10) in the upper ring (30) and unwinding of the intermediate ring (20) in the interval between the lower ring (10) and the upper ring (30) . 2) folding screen according to claim 1, characterized in that the junction line (11, 31) of the lower (10) and upper (30) crowns is distinct from the articulation line (21, 22) of the crown intermediate (20) and the interval between the respective lines (11, 21) and (22, 31) forms flexible marginal strips (24, 25). 3) folding screen according to claim 1, characterized in that the lower (10) and upper (30) rings are of frustoconical shape. 4 °) folding screen according to claim 1, characterized in that the lower (10) and upper (30) rings are of cylindrical shape. 5 °) Folding screen according to claim 1, characterized in that the lower (10), intermediate (20) and upper (30) rings are produced separately to be assembled and secured. 6 °) folding screen according to claim 1, characterized in that the lower, intermediate and upper rings are made in one piece by injection of several materials.