RETAINING PLATE FOR A VACUUM-CLEANER FILTER BAG

Abstract

The invention comprises a retaining plate (1), comprising a first plate (2) and a second plate (3) arranged in a first plane, and a third plate (8) arranged in a second plane which runs in parallel to the first plane, the third plate (8) having a lower flexural stiffness than the first plate (2) and the second plate (3), wherein the first plate (2) and the second plate (3) are interconnected by means of the third plate (8) such that a hinge is formed between the first plate (2) and the second plate (3) about the hinge axis (A) of which the first plate (2) and/or the second plate (3) can be bent together with the respective part of the third plate (8) connected thereto.

Description

The invention relates to a retaining plate for a vacuum-cleaner filter bag and to a vacuum-cleaner filter bag having such a retaining plate.

Many solutions are known to fix vacuum-cleaner filter bags in the installation space of the vacuum cleaner. In most cases, so-called retaining plates are used, that means flat components which are connected with the bag wall of the vacuum-cleaner filter bag and have a passage opening overlapping the admission opening of the bag wall. The retaining plate is pushed into a corresponding mounting in the vacuum cleaner before the latter is switched on, so that it is arranged in a certain position. When the vacuum cleaner is subsequently closed, a connecting piece of the vacuum cleaner engages with the passage opening of the retaining plate so that the air to be filtered can flow into the vacuum-cleaner filter bag. Moreover, solutions are known which do not use any retaining plate but are based, for example, on connecting pieces which are put onto corresponding counterparts in the installation space of the vacuum cleaner, as is disclosed, for example, in U.S. Pat. No. 2,068,332.

Due to limitations with respect to the installation space, retaining plates which include flexible regions were suggested, so that the actually flat components can also be pushed into bent guides. By this, a better adaptation to the installation space is to be permitted. Examples of such retaining plates are known from WO 2017/194081 A1 and WO 2017/196211 A1. One suggested solution uses integral hinges in order to design one region of the retaining plate flexibly. However, this can easily lead to component failures due to integral hinges which cannot be sufficiently loaded mechanically. In particular, the integral hinges can be even more weakened by the use of recycled plastics, such as recycled polypropylene, rPP. For ecological deliberations, the use of recycled plastics is becoming increasingly desirable. Moreover, the formation of the integral hinges by injection molding is also cumbersome.

It is therefore the object of the invention to provide an improved retaining plate for a vacuum-cleaner filter bag which is in particular more reliably applied and easier to manufacture.

This object is achieved by a vacuum-cleaner filter bag according to claim 1. Particularly advantageous developments can be found in the subclaims.

That means, the invention provides a retaining plate comprising a first plate and a second plate arranged in a first plane, and a third plate arranged in a second plane which runs parallel to the first plane, the third plate having lower flexural stiffness than the first plate and the second plate, the first plate and the second plate being interconnected by means of the third plate such that a hinge is formed between the first plate and the second plate about the hinge axis of which the first plate and/or the second plate can be bent together with the respective part of the third plate connected thereto.

By the hinge not being formed by a weakening line in the material as is common in prior art, but by a combination of the three plates, the retaining plate, in particular the hinge, can be designed to have a more reliable function and to be more flexible in view of the properties to be achieved. For example, plates that have been produced with different manufacturing processes can be also combined. Thus, one or more plates having a particularly sophisticated geometry can be molded parts. For simpler structures, the thermoforming method is also suited. It is thus also possible to combine various materials. For example, the third plate which is bent in use can also comprise a material which is particularly suited for this, such as for example a thermoplastic elastomer, TPE, or consist thereof. It is thereby then also possible to realize a seal integrally around the vacuum-cleaner connecting piece through the third TPE plate.

The term “plate” here refers to a flat component, that means a component whose extension in one plane (plate width and plate length) is clearly larger than its extension perpendicular to this plane (plate thickness).

The flexural stiffness describes the resistance of the plate against elastic deformation by a bending moment and is defined in the manner known to the person skilled in the art.

The third plate can have a one-piece design or be made of a plurality of interconnected parts. However, the third plate is in any case designed such that it connects the first plate with the second plate.

The retaining plate can in particular comprise one or more plastics or consist of one or more plastics. In particular, recycled plastics can also be employed, such as recycled polypropylene, rPP, and/or recycled polyethylene terephthalate, rPET. The recycled plastic material can in particular be used for the first plate and the second plate. The third plate can then also comprise new plastic material (virgin material) or consist thereof.

The retaining plate can be formed of a combination of molded parts or a combination of parts produced by thermoforming. The retaining plate can also comprise elements partially made by injection-molding and partially by thermoforming.

The first plate can in particular be connected with the second plate only via the third plate. In other words, the first plate and the second plate can be completely separate components. However, this does not exclude that a physical contact between the first plate and the second plate is present or can be present in certain positions. Here, the contact surface can also be selectively formed, for example drawn upwards at the edge, to achieve a larger contact surface and/or to permit a movement only in one direction and/or to restrict the possible bending angle.

The hinge axis can in particular extent in parallel to the parting line between the first plate and the second plate. The hinge axis then also lies in a plane parallel to the first and second planes, in particular in the second plane.

The third plate can in particular be thinner than the first plate and/or the second plate. The thickness is here determined perpendicular to the first and second planes. With a non-constant thickness, the average thickness can be taken as a quantity. By the smaller thickness, a higher flexibility, that means a lower flexural stiffness, can be achieved in a simple manner, in particular also if the same material is used for all plates. For example, the third plate can have a thickness of 0.05 to 1.0 mm, while the first plate and the second plate each have a thickness of 1.0 to 3.0 mm.

The third plate can, as an alternative or additionally, be made of a material different from that of the first plate and/or the second plate, the material of the third plate having a lower elastic modulus than the material of the first plate and/or the second plate.

The first plate and the second plate can be glued, welded, or positively connected to the third plate. The connection can be designed to be detachable nondestructively or not nondestructively. As a positive connection, a rivet connection is in particular possible.

In the first plate, a passage opening can be arranged which in particular overlaps with a passage opening in the third plate. The passage opening or openings form the filling hole when the retaining plate is connected with a vacuum-cleaner filter bag.

The retaining plate can moreover comprise a sealing lip surrounding the passage opening. The sealing lip can comprise or consist of a thermoplastic elastomer, for example based on polypropylene. The sealing lip is to prevent or restrict dust from leaking from the vacuum-cleaner filter bag by sealing the region between the inner edge of the passage opening and the outside of a connecting piece of the vacuum cleaner. It is in particular possible to form the sealing lip by parts of the third plate if it comprises or consists of a thermoplastic elastomer, TPE, by the passage opening in the third plate having a smaller diameter than the passage opening in the first plate.

In the second plate, one or more positioning openings can be provided for positioning and/or fixing it in a retaining plate mounting. In the third plate, correspondingly overlapping positioning openings can be provided so that the positioning openings are present in the retaining plate in the form of passage openings. However, the positioning openings can also be designed as blind holes. In operation, positioning elements of the retaining plate mounting of the vacuum cleaner can engage with the positioning openings and thereby position and/or fix the retaining plate.

The invention moreover provides a vacuum-cleaner filter bag comprising a bag wall and a retaining plate described above and connected therewith.

The bag wall is made from an air-permeable material and can be made in multiple layers. The latter is also referred to as a laminate. Multiple layers of the laminate, in particular each layer of the laminate, can comprise a non-woven fabric and/or a fibrous web or consist thereof.

As a material for the bag wall, in particular for one or several layers of non-woven fabric or fibrous web, many diverse plastics can be used, for example polypropylene and/or polyester. The bag wall can also comprise or consist of plastic recyclates and/or recycled material from the manufacture of textiles (Textile Left-Over—TLO).

For many plastic recyclates, there are relevant international standards. For PET plastic recyclates, for example, DIN EN 15353:2007 is relevant. PP recyclates are characterized in DIN EN 15345:2008. For the purpose of the corresponding special plastic recyclates, the present patent application adopts the definitions of these international standards. The plastic recyclates can be non-metallized. One example of this are plastic flakes or chips recovered from PET beverage bottles. Equally, the plastic recyclates can be metallized, e. g. if the recyclates have been obtained from metallic plastic foils, in particular metallized PET foils (MPET).

Recycled polyethylene terephthalate (rPET) can be obtained, for example, from beverage bottles, in particular so-called bottle flakes, that means pieces of ground beverage bottles.

The recycled plastics, in particular recycled PET and/or recycled PP, both in the metallized and in the non-metallized version, can be spun into the corresponding fibers from which the corresponding staple fibers or melt-blown or spunbond non-woven fabrics can be manufactured for the purposes of the present invention.

Recycled material from the manufacture of textiles (TLO) is in particular generated in the processing of textile materials (in particular textile fibers and filaments, and linear, planiform, and spatial textile fabrics manufactured therewith), such as, for example, the manufacture (comprising carding, spinning, cutting, and drying) or the recycling of textile materials. These pulverized and/or fibrous materials are waste materials which can deposit on the machines or filter materials used for processing the textiles. The dusts (powders) or fibers are normally disposed of and thermally utilized.

So, the pulverized and/or fibrous recycled material is, for example, production waste; this in particular applies to material generated during the carding, spinning, cutting, or drying of textile materials as a waste product. This is also referred to as “pre-consumer waste”.

Also in the recycling of textile materials, i. e. the processing (for example crushing) of used textile materials or textiles (for example old clothes), pulverized and/or fibrous recycled material is formed, this is referred to as “post-consumer waste”.

So, the recycled material from the manufacture of textiles, TLO, can in particular comprise fibers and/or filaments which have been obtained from waste materials from the textile and clothing industry, from post-consumer waste (textiles and the like), and/or from products that have been collected for recycling.

In the sense of the present invention, a non-woven fabric designates an entangled mesh that has undergone a solidification step so that it has sufficient strength to be wound off or up from or onto rolls, for example by machines (i. e. on an industrial scale). The minimum web tension required for winding up is 0.044 N/mm. The web tension should not be higher than 10% to 25% of the minimum maximum tensile force (according to DIN EN 29073-3:1992-08) of the material to be wound up. This results in a minimum maximum tensile force for a material to be wound up of 8.8 N per 5 cm of the strip width.

A fibrous web, briefly only referred to as “web”, corresponds to an entangled mesh which, however, has not undergone a solidification step, so that in contrast to a non-woven fabric, such an entangled mesh does not have sufficient strength to be wound off or up, respectively, into or from rolls, for example by machines.

The term non-woven fabric (“non-woven”) is used in other words according to the definition of ISO Standard ISO9092:1988 or CEM Standard EN29092. Details on the use of the definitions and/or methods described herein can also be taken from the standard work “Vliesstoffe”, W. Albrecht, H. Fuchs, W. Kittelmann, Wiley-VCH, 2000.

The non-woven fabric layers of the bag wall can in particular comprise a staple fiber non-woven fabric and or an extrusion non-woven fabric. In particular, spun-bond nonwovens (briefly also “spun-bond web” or spundbond”), and/or melt-blown non-woven fabric can be used.

One or several layers of the bag wall can comprise a carded material. As a bonding step, mechanical methods (e. g. needling) as well as thermal methods (e. g. calendaring) are possible. Equally, the use of binding fibers or adhesives, such as a latex adhesive, is possible. Airlaid materials are also possible.

The non-woven fabric of one or several layers of the bag wall can comprise bicomponent fibers. Bicomponent fibers (bico fibers) can be formed of a core and an envelope enclosing the core. Apart from core/envelope bicomponent fibers, the other common variations of bicomponent fibers, e. g. side-by-side, can be employed.

The bicomponent fibers can be present as staple fibers or be formed as filaments in an extrusion non-woven fabric (for example, melt-blown non-woven fabric).

Correspondingly non-solidified fibrous webs are also conceivable, as mentioned.

The non-woven fabric of one or several layers of the bag wall can moreover include a microcreping (Micrex).

The bag wall can also comprise an odor absorbent.

The bag wall can in particular comprise a capacity layer. A capacity layer offers a high resistance against shock loads and permits filtering of large particles of dirt, filtering a significant proportion of small particles of dirt, and storing or retaining high amounts of particles, wherein the air is allowed to easily flow through, thus resulting in a low pressure drop with a high particle load.

The bag wall can also comprise a fine filter layer. A fine filter layer serves to increase the filtration performance of the multi-layer filter material by capturing particles which penetrate, for example, the capacity layer. To further increase the separation performance, the fine filter layer can be preferably charged electrostatically (e. g. by corona discharge or hydro-charging), to in particular increase the separation of particulate matter.

The fine filter layer can be adjacent to the capacity layer in particular towards the outside of the bag wall.

A support layer can also be adjacent to the fine filter layer. A support layer (sometimes also referred to as “reinforcement layer”) is here a layer that imparts the required mechanical strength to the multi-layer bond of the filter material. The support layer can in particular be an open, porous non-woven fabric with a light grammage. The support layer can in particular be a spun-bond web.

However, it is also possible to employ a single-layer filter material for the bag wall. In this case, it can in particular be a melt-blown non-woven fabric. A suited material for such a single-layer bag wall is known, for example, from EP 2 311 360 B1.

The retaining plate can comprise one or several ones of the above-described features.

The bag wall can in particular be welded to the third plate, the third plate comprising a plastic which is compatible with the plastic material of the outermost layer of the bag wall to which the third plate is welded. In other words, the material of the third plate can be selected such that it can be welded to the bag wall as firmly as possible.

For good welding results, it is necessary for the materials to be connected to be preferably matched both with respect to their melting points and their chemical natures (amorphous/semicrystalline). This can be achieved if compatible materials are used. It is also conceivable to use the same materials for the outermost layer of the bag wall, to which the third plate is welded, and for the third plate.

However, it is also possible for the bag wall to be connected with the first plate or the second plate. In this case, the respective plate can comprise a plastic compatible with the plastic material of the outermost layer of the bag wall to which the respective plate is welded.

The invention moreover provides a system comprising a vacuum-cleaner filter bag described above and a mounting for the retaining plate in a vacuum-cleaner housing, wherein the mounting is designed such that the first plate and/or the second plate and the respective part of the third plate connected thereto are bent about the hinge axis in the operating position with respect to the first and second planes. The operating position is defined here as the position in which the retaining plate is arranged in the operation of the vacuum cleaner.

The vacuum-cleaner filter bag can comprise one or several ones of the above-described features.

The mounting can in particular have a guide along which the retaining plate can be inserted into the mounting. This guide can comprise a straight and a bent section. By the bent section, the bending about the hinge axis can be caused.

The mounting can in particular be designed as described in WO 2018/095519 A1.

Further features and advantages of the invention will be described below with reference to the exemplary figures. In the drawings:

FIG. 1 shows a plan view onto an exemplary retaining plate;

FIG. 2 shows a section through an exemplary retaining plate;

FIG. 3 shows a side view of an exemplary retaining plate in a first position;

FIG. 4 shows a side view of an exemplary retaining plate in a second position; and

FIG. 5 shows a plan view onto an exemplary vacuum-cleaner filter bag.

FIG. 1 shows a plan view onto an exemplary retaining plate 1, comprising a first plate 2 and a second plate 3 which are embodied as completely separate components. In this example, the plates 2, 3 are spaced apart by a gap 7. It would also be conceivable for the plates 2, 3 to touch each other in this arrangement as long as they remain separate components. The first plate 2 and the second plate 3 are only connected by a third plate which cannot be seen in FIG. 1 and which is arranged in a plane parallel to the plane of the first plate 2 and the second plate 3 and is in particular also provided in the region under the gap 7.

FIG. 2 shows a section through the exemplary retaining plate 1. The third plate 8 is arranged under the first plate 2, the second plate 3, and in particular under the gap 7, so that the third plate 8 connects the plates 2, 3. The third plate 8 is arranged on the side of the retaining plate 1 that is provided for the connection with the bag wall of a vacuum-cleaner filter bag.

The third plate 8 moreover has a lower flexural stiffness than the first plate 2 and/or the second plate 3. In this example, this is achieved in that the third plate 8 is thinner both than the first plate and the second plate 3. As an alternative or in addition, the third plate 8 can be made of a material different from that of the first plate 2 and/or the second plate 3, wherein the material of the third plate has a lower elastic modulus than the material of the first plate 2 and/or the second plate 3.

By the higher flexibility of the third plate and the reduced thickness of the retaining plate 1 in the region of the gap 7 between the plates 2, 3, a hinge is formed. The hinge axis A is indicated in FIG. 1 by a dashed line. The second plate 3 can be bent or pivoted about this hinge axis A with respect to the first plate 2 together with the part of the third plate 8 connected thereto. This is represented in FIGS. 3 and 4. In FIG. 3, all plates 2, 3, 8 are completely located in two parallel planes, while in FIG. 4, the second plate 3 and the part of the third plate 8 connected thereto are bent about the hinge axis A perpendicularly to the planes of FIG. 3. Thereby, the retaining plate 1 can also be introduced into mountings which have a bent guide and thereby require a retaining plate with flexible regions.

As is shown in FIGS. 1 and 2, in the first plate 2, a passage opening 4 is formed which also extends, as is shown in FIG. 2, through the third plate 8. Thereby, an admission opening is formed together with a passage opening of the bag wall of a vacuum-cleaner filter bag. However, it is also conceivable that the third plate 8 does not extend over the complete bottom side of the first plate 1 and thus does not overlap the passage opening 4 in the first plate 2. The admission opening is then formed only by the passage opening 4 in the first plate 2 together with the passage opening of the bag wall.

The retaining plate 1 has a sealing lip 10 of a thermoplastic elastomer, TPE, in a manner known per se which is molded to the edge of the passage opening 4 of the first plate 2 in this example. However, it is also possible to form the sealing lip 10 by the third plate 8 if it comprises or consists of a thermoplastic elastomer, TPE, by the passage opening in the third plate 8 having a smaller diameter than the passage opening 4 in the first plate 2. According to further alternatives, the sealing lip 10 can also be glued or welded onto the first plate 2 from above or from the bottom. “Above” here refers to the side facing away from the third plate 8, and “bottom” to the side facing the third plate 8.

One can also see in FIG. 1 two positioning openings 5, 6 in the second plate 3 for positioning and/or fastening it in a retaining plate mounting. The positioning openings 5, 6 can also be provided as passage holes in the third plate 8. In operation, positioning elements of the retaining plate mounting of the vacuum cleaner can engage with the positioning openings 5, 6 and thereby position and/or fix the retaining plate 1.

In FIG. 5, the retaining plate 1 is connected to a bag wall 9 of a vacuum-cleaner filter bag. The bag wall 9 can in particular be welded to the third plate 8, the third plate 8 comprising a plastic which is compatible with the plastic material of the outermost layer of the bag wall 9 to which the third plate 8 is welded. Thereby, the strength of the welded joint between the retaining plate 1 and the bag wall 9 can be improved.

The bag wall 9 comprises a plurality of non-woven fabric layers or a plurality of non-woven fabric and fibrous web layers which overlap each other from the bag's interior to the bag's exterior. The non-woven fabric or fibrous web layers can be loosely lie one upon the other or be connected to each other. The connections can be accomplished across the surface (e. g. via spray adhesives), or punctually (e. g. via a calendaring pattern).

The individual layers can in particular comprise different plastic materials, both among each other and/or within one respective layer.

The exemplary vacuum-cleaner filter bag of FIG. 5 is a so-called flat bag wherein the bag wall 9 comprises an upper side and a bottom side which are connected to each other by a surrounding weld seam. Both the upper side and the bottom side of the flat bag comprise, as mentioned above, a plurality of filter material layers, in particular a plurality of non-woven fabric layers or a plurality of non-woven fabric and fibrous web layers. Both the upper side and the bottom side can in particular be formed of a laminate of a plurality of non-woven fabric layers. However, the invention is not limited to flat bags but can also be applied, for example, for gusset bags or pad bottom bags.

Advantageously, the retaining plate 1 in this example comprises a recycled plastic material, for example, recycled polypropylene (rPP) or recycled polyethylene terephthalate (rPET).

It will be understood that features mentioned in the above-described embodiments are not restricted to these special combinations and are also possible in any other combinations. It will be furthermore understood that geometries shown in the figures are only given by way of example and are also possible in any other designs.

Claims

1. A retaining plate, comprising a first plate and a second plate arranged in a first plane, and a third plate arranged in a second plane which runs in parallel to the first plane, the third plate having a lower flexural stiffness than the first plate and the second plate, wherein the first plate and the second plate are interconnected by means of the third plate such that a hinge is formed between the first plate and the second plate about a hinge axis (A) of which the first plate and/or the second plate can be bent together with a respective part of the third plate connected thereto.

2. The retaining plate according to claim 1, wherein the third plate is designed to be thinner than the first plate and/or the second plate.

3. The retaining plate according to claim 1, wherein the third plate is made of a material different from that of the first plate and/or the second plate, wherein the material of the third plate has a lower elastic modulus than the material of the first plate and/or the second plate.

4. The retaining plate according to claim 1, wherein the first plate and the second plate are glued, welded, or positively connected to the third plate.

5. The retaining plate according to claim 1, wherein in the first plate, a passage opening is arranged which in particular overlaps with a passage opening in the third plate.

6. The retaining plate according to claim 1, wherein in the second plate, one or more positioning openings are provided for positioning and/or fastening it in a retaining plate mounting.

7. A vacuum-cleaner filter bag, comprising:

a bag wall and a retaining plate connected thereto;

wherein the retaining plate comprises a first plate and a second plate arranged in a first plane, and a third plate arranged in a second plane which runs in parallel to the first plane, the third plate having a lower flexural stiffness than the first plate and the second plate; and

wherein the first plate and the second plate are interconnected by means of the third plate such that a hinge is formed between the first plate and the second plate about a hinge axis (A) of which the first plate and/or the second plate can be bent together with a respective part of the third plate connected thereto.

8. The vacuum-cleaner filter bag according to claim 7, wherein the bag wall is welded to the third plate, and wherein the third plate comprises a plastic which is compatible with a plastic material of an outermost layer of the bag wall to which the third plate is welded.

9. A system, the system comprising:

a vacuum-cleaner filter bag, the vacuum-cleaner filter bag comprising: a bag wall and a retaining plate connected thereto; and wherein the retaining plate comprises a first plate and a second plate arranged in a first plane, and a third plate arranged in a second plane which runs in parallel to the first plane, the third plate having a lower flexural stiffness than the first plate and the second plate, and wherein the first plate and the second plate are interconnected by means of the third plate such that a hinge is formed between the first plate and the second plate about a hinge axis (A) of which the first plate and/or the second plate can be bent together with a respective part of the third plate connected thereto; and

a mounting for the retaining plate in a vacuum-cleaner housing, wherein the mounting is designed such that the first plate and/or the second plate and the respective part of the third plate connected thereto are bent about the hinge axis (A) in an operating position with respect to the first and second planes.

10. The retaining plate according to claim 2, wherein the third plate is made of a material different from that of the first plate and/or the second plate, and wherein the material of the third plate has a lower elastic modulus than the material of the first plate and/or the second plate.

11. The retaining plate according to claim 10, wherein the first plate and the second plate are glued, welded, or positively connected to the third plate.

12. The vacuum-cleaner filter bag according to claim 8, wherein the third plate is designed to be thinner than the first plate and/or the second plate.

13. The vacuum-cleaner filter bag according to claim 8, wherein the third plate is made of a material different from that of the first plate and/or the second plate, and wherein the material of the third plate has a lower elastic modulus than the material of the first plate and/or the second plate.

14. The vacuum-cleaner filter bag according to claim 8, wherein the first plate and the second plate are glued, welded, or positively connected to the third plate.

15. The vacuum-cleaner filter bag according to claim 8, wherein in the first plate, a passage opening is arranged which in particular overlaps with a passage opening in the third plate.

16. The system according to claim 9, wherein the third plate is designed to be thinner than the first plate and/or the second plate.

17. The system according to claim 9, wherein the third plate is made of a material different from that of the first plate and/or the second plate, and wherein the material of the third plate has a lower elastic modulus than the material of the first plate and/or the second plate.

18. The system according to claim 9, wherein the first plate and the second plate are glued, welded, or positively connected to the third plate.

19. The system according to claim 9, wherein in the first plate, a passage opening is arranged which in particular overlaps with a passage opening in the third plate.

20. The system according to claim 9, wherein in the second plate, one or more positioning openings are provided for positioning and/or fastening it in a retaining plate mounting.