Self-Inflating Screening Shield, in Particular Umbrella

The present invention relates to a self-inflating screening shield, in particular umbrella, according to the preamble of claim 1. The invention also relates to a self-inflating balloon according to the features of claim 10.

Conventional umbrellas in everyday use are generally relatively bulky devices that are often inconvenient to handle. They are annoying particularly when they are not being used, i.e. as long as the anticipated rain has not yet started, or when it has stopped raining. In addition, they are often left behind or forgotten, due to the very fact that they are not easily transportable. This, in turn, often leads to them not being taken when no rain is expected. If it starts to rain after all, one is largely unprotected, or tries to protect oneself against the rain in a makeshift manner by holding items such as bags, or articles of clothing such as jackets and the like, over one's head, but with the consequence that these items and clothing articles are damaged.

Since this basic problem has long been known, partly telescoping umbrellas were designed a long time ago that require substantially less space when closed than is the case with conventional umbrellas, but which are still relatively large and bulky. Although it is possible to accommodate these in a bag or the like that one is carrying, the considerable weight of such umbrellas is annoyingly noticeable. If there is no intention to carry a bag, umbrellas of the latter kind are likewise impracticable to transport.

The problems outlined in the foregoing are further exacerbated by the fact that changes in global climate conditions could lead to local weather conditions changing more quickly from one extreme to the other. Within a few hours or an even shorter period of time, the weather situation and particularly the likelihood of rain can therefore change in a fundamental way. This gives rise to a need to be able to protect oneself against sudden rain showers in effectively any outdoor situation.

It can be seen from the published prior art that one aim in improving the ease of handling of umbrellas is to reduce their bulkiness, i.e. to decrease the number and/or size of bulky parts in umbrellas. The bulkiness of conventional umbrellas is due, in particular, to the handle member, the central support rod and the radial struts which tension the screening material. One aim of further developments must therefore be to replace these elements with other elements that functionally are approximately equivalent.

In a number of documents, it has therefore been proposed to configure an umbrella as an inflatable umbrella that is inflated for use and can otherwise be transported in a practicable manner in a folded-together form. A gas-filled envelope replaces the screening material commonly tensioned by metal struts, thus ensuring the necessary stiffness.

Document DE 20 2004 002 172 U1 describes an umbrella or sunshade which is provided with an inflatable umbrella- or disk-shaped air chamber coupled to a compressed air cartridge. By means of a valve which can be actuated by a push-button, it is possible to control the supply of air from the cartridge to the air chamber. When the umbrella or sunshade is no longer needed, the air is released from the air chamber by means of the valve and the umbrella or sunshade is folded up and stowed in a case.

In document U.S. Pat. No. 3,889,700, a compact, self-inflating umbrella for once-only use is proposed. The umbrella is provided with a case, the bottom portion of which serves as a handle member when using the umbrella. Inside the case, near the bottom thereof, a pressure vessel filled with a pressurised boiling liquid is disposed. Above said vessel, the inflatable shielding screen is stowed away in a folded state inside the case. When in use, a closure element of the pressure vessel is broken away by external mechanical action so that the liquid escapes through the opening thus produced, expands thereby and is guided as a gaseous substance into the inflatable chambers of the screening shield. As a result of the air chambers being inflated, the screening shield is pressed out of the upper part of the case and unfolds to its full size. The umbrella is thrown away after one use.

For several reasons, these different approaches to solving the aforementioned problem have not been able to establish themselves by widespread use. Firstly, the proposed umbrellas include bulky elements such as handle members, cases or gas production devices, with the result that, in the unopened state, they are still too bulky and require too much space. In other words, a decisive technical advance compared to standard telescoping pocket umbrellas cannot be achieved with such approaches. Secondly, the gas production devices provided in them for inflating the screening shield are too complex in design and too expensive to produce, with the consequence that inflatable umbrellas produced in this manner, especially those for once-only use, can not be offered at an attractive price.

The object of the present invention is therefore to specify a self-inflating umbrella which is space-saving when not in use and which can also be produced with less production effort. The object of the present invention, more particularly, is to define a self-inflating umbrella which essentially no longer contains any bulky elements.

These objects are achieved by the feature of the characterising portion of claim 1. Advantageous developments and configurations of the invention are described in subclaims.

A self-inflating screening shield according to the present invention comprises an inflatable envelope made of flexible material, wherein a gaseous substance can be produced inside the envelope by means of a chemical reaction. In one embodiment, said screening shield is an umbrella. In another embodiment, said screening shield is a sunshade.

The present invention thus proceeds from the basic realisation that the devices proposed in the published prior art for providing or producing a gas for inflating the shielding envelope are invariably too voluminous in design and therefore too bulky, since the medium to be used for inflation must be enclosed in a pressure-tight container when not in use, be it in the form of a compressed air cartridge or a pressurised boiling liquid enclosed in a container.

One essential idea of the present invention is therefore to provide the gaseous substance for inflating the umbrella in some other manner that obviates the need to use bulky containers. This is made possible by the present invention.

The inventive idea provides the basis for storing certain starting substances, with the aid of which the gaseous substance is to be produced, without using rigid pressure vessels as storage. Another advantage is that individual chambers can be separately filled with gas by means of said starting substances. More particularly, two or more chemical substances can be disposed, as starting substances for the chemical reaction, spatially separate from each other inside the envelope, and the chemical reaction can be triggered, in case of use, by the chemical starting substances being brought into contact with each other. This basically obviates the need for the chemical starting substances to be accommodated in rigid, pressure-tight containers. It is not even necessary, in essence, for them to be accommodated in containers at all when in their initial state.

However, one exemplary and advantageous embodiment provides that at least one of the chemical substances is accommodated in a container which can be opened externally by the effect of pressure, such that the chemical substance contained therein is released and can come into contact with the respective other chemical substance. For example, it can then be arranged that the container is disposed at a defined position inside the envelope, and that a marking is applied at a location on the outer wall of the envelope which is closest to said position. The marking, which may also be configured as a predetermined breaking point, serves to indicate to the user that the marked place be pressed in case of use, thus opening the container by the effect of pressure. The container may be provided, for example, with a flexible outer skin, so that the container can be made to rupture by the effect of mechanical pressure, and the chemical substance contained therein can escape. In another embodiment, the container may be configured in such a way that it is opened by tensile force.

In one embodiment, a plurality of separate air chambers are provided, and each air chamber is filled with air by means of a chemical reaction specific to that chamber. In one embodiment there are two such chambers, in another embodiment three chambers, in another embodiment four chambers and in yet another embodiment five chambers. In one embodiment, the shielding screen is filled with one chamber, while the handle is filled with a separate chamber. In this way, the user can firstly open the shielding screen by means of a first reaction, and then “open” the handle by triggering a second reaction. In another embodiment, the shielding screen is only partially fitted with air chambers, with material, for example, being provided between the chambers. In one embodiment, the chambers are located where the frame for opening the shielding screen is normally located. This means that the chambers are attached in a star-shaped formation in such a way that the shielding screen is opened between them. The chambers can also be filled with gas separately in this way, with each chamber then being assigned a specific mixture of chemicals. This advantage is absent from the prior art, since a plurality of pressure cartridges cannot be used.

With regard to the starting substances for the chemical reaction, a first chemical substance may contain or consist of a solid, and a second chemical substance may contain or consist of a liquid, and when the substances come into contact, the chemical reaction may consist in the solid being dissolved by the liquid, with the gaseous substance being one of the reaction products. In one practical embodiment, the solid may contain or consist of sodium carbonate (washing soda) or sodium bicarbonate (baking soda), and the second chemical substance may comprise an acid. When said solids are dissolved in the acid, gaseous CO₂is produced as the reaction product. Citric acid, practicably as an ingredient of lemon juice, or tartaric acid may be used as the acid.

As an alternative to the choice of material proposed above for the first and second chemical substance, a different solid which can be dissolved in a liquid may be chosen for the first chemical substance such that a gaseous substance such as CO₂or O₂is released when the solid is dissolved in the liquid. For example, the solid may also be provided by a kind of effervescent powder, and the liquid in the simplest case by water, so that the desired result of a chemical reaction, with the formation of a gaseous substance, can likewise be achieved.

The solid should preferably be present in the form of a powder or granulate, so that it has as much free surface exposed to the liquid as possible.

In one preferred embodiment, bulk sodium bicarbonate, preferably in the crystal phase (e.g. 4.88 g (58 mmol)), and a solution of citric acid and water, preferably 3.78 g (19.7 mmol) citric acid and 16 ml water, which is e.g. sealed into a thin plastic bag (e.g. 6×6 cm format), are provided in the loop which is configured as a carrying handle. The aforementioned quantities produce 1.3 litres in volume of gas, which, in a shielding screen with a volume of 1 litre, produces the slight 0.3 bar of overpressure necessary to unfold said shielding screen.

In general, X=V(p+Δp)/22.4;

where X is the number of mols (of gas/acid/base)

- V is the volume [in litres] of the shielding screen
- p is the ambient pressure (1 bar)
- and Δp is the overpressure [in bar]

In the case of polybasic acids (e.g. citric acid), the number of mols X must be divided by the basicity (in the case of citric acid: 3). The same principle applies accordingly in the case of bases.

The advantage is that the combination of substances can be stored in this form without limits, which is important particularly in the case of a disposable shielding screen. When in use, the plastic bag is preferably made to rupture by applying pressure, for example by a finger, and the formation of CO₂occurs without further extrinsic action, thus making the screening shield unfold. A kind of ripcord which opens the bag of liquid may also be attached.

In one particularly preferred embodiment, the following reaction is carried out:

3 NaHCO₃+C₆H₈O₇=3 CO₂+C₆H₅O₇Na₃+3H₂O

in words:

sodium bicarbonate+citric acid=carbon dioxide+sodium citrate+water

Sodium bicarbonate is preferred because it is twice as effective as sodium carbonate. Furthermore, it is safer and more environmentally friendly because it is not as strongly alkaline as sodium carbonate.

Other possible acids are malic acid, tartaric acid, succinic acid, amidosulphonic acid or fumaric acid, for example. The criterion for selection is the lowest possible level within the classification of hazardous substances. The aforementioned acids, including citric acid, are classified as “irritant”, whereas acetic acid, for example, is “corrosive”. A low classification as hazardous substance is advantageous. An acid classified as “irritant” is therefore preferred.

The overpressure Δp in the chamber is preferably more than 0.1 bar, more preferably between 0.1 and 2 bar, even more preferably between 0.2 and 1 bar, and especially preferably between 0.3 and 0.5 bar. A higher pressure may be used in the case of stronger material.

In one preferred embodiment, coloured substances or dyes are carried by the gas (CO₂) which propagates in the screening shield, said coloured substances or dyes being fluorescent or phosphorescent, or made to glow in some other way.

A handle member in the form of a flexible loop may also be provided at a position on the outer wall of the envelope.

With the present invention and, where relevant, with the developments and embodiments specified in the foregoing, it is possible for the self-inflating screening shield to be folded together in its initial state to a very space-saving size, since it no longer has any bulky, space-consuming parts.

In the folded-together form, a self-inflating screening shield can be carried easily in a jacket or trouser pocket. When needed, it can be activated by applying pressure is to the marking on the outer skin of the envelope so that the chemical reaction is initiated inside it. Due to the vacuum inside the envelope or inside the chambers to be inflated, when in the initial state, the gaseous substance produced by the chemical reaction flows very rapidly into the envelope or chambers and thus inflates these very quickly, with the result that the screening shield or umbrella is available within a very short period of time. Since the screening shield is envisaged for once-only use, it may be thrown away as soon as it is no longer needed. After use, the chemicals used to inflate the screening shield are absolutely non-hazardous, are neutral in water, do not pose a hazard for water resources and are biodegradable.

In one embodiment, a material such as that used in vehicle airbags is used. The air chambers may have threads or transversal connectors on the inside. The upper and lower sides may be connected, or the lateral sides. The air chamber may be bowl-shaped. A water-repellent material is preferred. The screening shield may also have a double-walled construction. Parts of the screening shield may comprise carbon nanotubes. These may be embedded in the screening shield material. Kevlar fibres may also be used.

Polyethylene terephthalate (PET) is also a preferred material. A polyethylene terephthalate polyester film (BOPET: biaxially oriented polyethylene terephthalate) such as Mylar® is particularly preferred. Mylar® is characterised above all by its high tensile strength, chemical resistance, plastic stability and translucency or transparency, and is an electrical insulator. These properties are advantageous for the inventive screening shield.

The screening shield is made by sewing, welding or glueing, for example. Air-tightness is important both for the selection of material and for production.

Seams and material must be chosen such that they withstand the pressure of the gas volume and no gas escapes.

In addition, the handle may be connected to the screening shield by threads. The preferred connection is one which provides the longest path between the outer edge of the screening shield and the handle. A radial distribution is preferred.

The material of the screening shield may be coloured or transparent. It can also be phosphorescent or fluorescent. The material of the screening shield may have a signal colour.

In one embodiment, the screening shield has an edge which prevents water from flowing under the screening shield. In another embodiment, an air chamber forming a bulge is provided in the shape of a circle around the edge of the screening shield.

In one embodiment, the chambers which hold the chemicals have predetermined breaking points. If the chemicals are in bags, said bags may have perforations. One particularly preferred embodiment is one in which the screening shield is rod-shaped when in the folded-together state. In this case, the predetermined breaking point is preferably provided in the middle of the rod so that the chemical reaction is triggered by simply pressing against the predetermined breaking point of the rod or breaking the same.

In one embodiment, the material of the screening shield is folded using the origami technique after it has been glued or welded.

In one particularly preferred embodiment, the material of the screening shield is itself biodegradable.

EXAMPLES

The invention shall now be described in greater detail with reference to embodiments and to the drawings, in which:

FIG. 1 shows a perspective view (seen at an angle from above) of a first embodiment of a self-inflating screening shield or umbrella in the inflated state;

FIG. 2 shows a perspective view (from below) of the first embodiment as shown in FIG. 1;

FIG. 3 shows a cross-sectional view of a central chamber of the envelope of the self-inflating umbrella;

FIG. 4 shows a plan view of the folded-together umbrella, with the uppermost located central chamber; and

FIG. 5 shows a perspective view (seen at an angle from above) of a second embodiment of a self-inflating umbrella according to the invention.

FIG. 1 shows a perspective view from above of a first embodiment of a self-inflating umbrella according to the invention. The self-inflating umbrella 10 essentially comprises an inflatable envelope 11 made of a flexible material, for example of a suitable plastic material such as polypropylene or the like. A suitable film material may also be used, as an alternative. When not in use, i.e. prior to inflation, there is a vacuum inside envelope 11, so it can be folded together into a very small space. Envelope 11 is produced in such a way that, when inflated, it adopts the shape of a dome as shown in FIG. 1, which can be held above one's head as a protection against rain. In the perspective view seen at an angle from below as shown in FIG. 2, it can be seen that a loop 13 made of a flexible material is attached to a central portion on the concave side of the dome, through which loop a hand can be placed when in use, so that the umbrella 10 can be held securely and reliably above the carrier's head. The umbrella 10 can be produced in different sizes. In the smallest embodiment, the diameter of the dome is just large enough for the head of the user to be covered. In somewhat larger embodiments, the dome can have a diameter of such size that the shoulder area of the user is covered as well. Envelope 11 may contain a central chamber 12 which may be of circular shape when viewed from above and the dimensions and boundaries of which may be visible to the outside. Production of the gaseous substance for activating and inflating umbrella 10 occurs in the central chamber 12.

In FIGS. 3 and 4, the central chamber 12 is shown in cross-section and in a plan view, respectively. Inside chamber 12, a container 12.2 containing citric acid or lemon juice is attached to a bottom surface 12.1. Laterally adjacent to container 12.2, a granulate or powder 12.3 consisting of washing soda (sodium carbonate) or baking soda (sodium bicarbonate) is disposed. A marking 12.4 is applied to the outer convex side of envelope 11. The outer wall of envelope 11 can be pressed in at this marking as far as container 12.2, such that container 12.2 can be compressed and made to rupture. As an alternative to marking 12.4, the outer skin of envelope 11 may be either wholly transparent, or transparent only in the region of central chamber 12, so that the user can visually perceive container 12.2 and can also observe the gas production process after container 12.2 has been forced to rupture.

Container 12.2 may consist of a small envelope or bag shaped out of plastic and filled with citric acid or lemon juice, which is square in shape and welded together at one or several of its lateral boundaries. When compressed, the envelope preferably tears at one or several of these seams. As is shown in FIG. 4, suitable precautions can be taken so that container 12.2 ruptures on one side only and hence its contents escape in one direction only, namely in the direction of the granulate 12.3. As shown, container 12.2 may be additionally reinforced at three lateral boundaries and connected to the floor side 12.1. When compressed, container 12.2 thus ruptures only on the left side. There a production-related seam may be located, or a predetermined breaking point, such as a perforation or the like, may be alternatively or additionally provided in the outer skin of container 12.2.

After container 12.2 has ruptured, the liquid contained therein escapes rapidly because of the vacuum inside central chamber 12 and the remaining interior of envelope 11. However, it has to be ensured that the lemon juice flows over granulate 12.3 in a directed manner and as completely as possible in order to bring about the chemical reaction, i.e. the dissolution of the sodium (bi)carbonate granulate 12.3. This can be achieved e.g. by covering the space in container 12.2 and the sodium (bi)carbonate granulate 12.3 by means of a membrane 12.5. Said membrane 12.5 consists of a material which is permeable to the gaseous substance produced by the chemical reaction, i.e. gaseous CO₂in the present embodiment, or it is provided alternatively with a dense network of pores through which only the gaseous substance can pass. Thus, it is ensured that neither the granulate 12.3 can enter chamber 12 and the remaining interior of envelope 11 before the umbrella 10 is put into use nor, after container 12.2 has been forced to rupture, the liquid is able to escape without coming into contact with the granulate 12.3. To this end, the liquid may have a surface tension which ensures that it cannot pass through the pores of membrane 12.5.

In the chosen embodiment, the granulate consists of washing soda, i.e. sodium carbonate with the chemical formula Na₂CO₃, or of baking soda, i.e. sodium bicarbonate with the chemical formula NaHCO₃. In the present embodiment, the acid used to dissolve the sodium (bi)carbonate granulate is citric acid with the chemical formula C₆H₈O₇. Lemon juice contains 5-7% citric acid, so it is possible in the simplest case for container 12.2 to contain lemon juice. Gaseous CO₂is produced as a reaction product when the sodium (bi)carbonate granulate is dissolved in citric acid. The equation for this chemical reaction is the following:

3 Na₂CO₃+2 C₆H₈O₇=3H₂O+3 CO₂+2 C₆H₅O₇Na₃

or, expressed in words:

sodium carbonate+citric acid=water+carbon dioxide+sodium citrate

However, it is also possible for a different acid, for example tartaric acid, malic acid, succinic acid, amidosulphonic acid or fumaric acid, to be used to dissolve the granulate.

The gaseous CO₂thus produced escapes very rapidly through the pores of membrane 12.5 into chamber 12 and from there into the remaining interior of envelope 11, thus inflating envelope 11. The base portion of envelope 11 may have a slightly greater thickness in the region of the central chamber 12 than the rest of the outer skin of envelope 11, in order to ensure the requisite stability and strength in said region. As shown in FIG. 3, loop 13 made of flexible material is externally attached to said base portion. Loop 13 preferably consists of a thin, space-saving layer of a suitable plastic material such as polypropylene. The outer edge of envelope 11 is also shown in FIG. 3. As can be seen, an upper envelope portion 11.1 can be welded together in this region with a lower envelope portion 11.2 along a circumferential seam 11.3.

FIG. 4 is simultaneously a plan view of the folded-together screening shield. During manufacture, the product is folded in such a way that the depicted square around the central chamber 12 results, wherein envelope 11 and loop 13 are folded together in a suitable manner in an image plane behind the square shown, and are connected to said square. Their actual proportions can correspond approximately to those shown in FIGS. 3 and 4. The square pack can therefore be easily carried in a pocket of an article of clothing. If desired, however, the square pack can be kept in an adapted case, in particular to avoid the screening shield being unintentionally triggered.

FIG. 5 shows a perspective view, seen at an angle from above, of a second embodiment of a self-inflating umbrella according to the invention. Unlike the first embodiment shown in FIG. 1, the self-inflating umbrella 20 has an envelope 21 which is provided with a number of inflatable channels 21.1 projecting radially from a central chamber 22, between which channels single-layered regions 21.2 not shaped as envelopes extend. Although an umbrella 20 of this kind is somewhat more complicated to manufacture, it can be inflated more quickly when used, because only channels 21.1 and hence less volume need to be filled with the gaseous substance that is produced. Chamber 22 has substantially the exact same shape as chamber 12 in FIGS. 3 and 4 of the first embodiment. The view shown in FIG. 3 can also serve as a cross-sectional view through the umbrella 20 in FIG. 5, wherein cross-section is through chamber 22 and two channels 21.1 extending therefrom.

Instead of seven channels 21.1, as shown in FIG. 5, more channels or less channels, for example only two or three channels, may also be used.

After one use, the self-inflating umbrella of the present invention can be thrown away. Environmentally friendly materials are therefore preferred.

The invention relates also to a self-inflating balloon in which the same principle is applied as in the umbrella described above, and in which all the other details and features can be applied as described above in connection with the self-inflating umbrella. For example, a simple toy balloon can be made, particularly in the form of a foil balloon made of a foil material, inside which there is a vacuum prior to use. A container filled with an acid such as citric acid can be disposed inside such a balloon, and a solid such as a sodium (bi)carbonate granulate can be disposed outside it. The container can be secured at a certain place inside the envelope, as described in the foregoing, and be suitably marked on the outside. However, the container can also be freely movable inside the envelope. If the balloon is small enough, it is possible to feel from the outside where the container is located. The sodium (bi)carbonate granulate can likewise be fixed at a certain place on the inside of the envelope, as described in the foregoing, or alternatively can be disposed in a freely moveable manner inside the envelope. If the balloon is small enough, the granulate will be covered almost completely by the liquid in such a case also. By pressing the outer skin of the balloon at a suitable place, the container can be made to rupture such that the balloon is inflated by the gas formed by the chemical reaction.

In the simplest embodiment, the balloon may comprise two parts, in particular foils, which are welded to each other at their respective circumferential rims and form a closed envelope in such a way that the envelope is filled with the container and the granulate and a vacuum otherwise prevails inside. The two foils are congruent with each other, i.e. they can be laid on top of each other in a perfect overlap. When inflated, the foils can also produce a figure such as an animal or the like. In the simplest case, the foils can also be circular in shape, so that the inflated balloon is shaped substantially like a ball or globe. The balloon can also be used as an advertising medium by printing an advertising message on the outer surface of the envelope.

Self-Inflating Screening Shield, in Particular Umbrella

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