INFLATED PACKAGING

The present invention refers to an inflating valve with non-return function to be used in making inflatable packaging, namely packaging which use air chambers for dampening obnoxious impacts and/or vibrations for a packaged product.

Inflatable packaging are a rather efficient and economic solution to contain and/or stabilize the loads during their transport. The use of technologically advanced production processes allows making extremely resistant envelopes, therefore capable of easily supporting the stresses which are generated during the transport of objects, even heavy, allowing their efficient protection, both if the objects are contained inside air chambers, and in case said air chambers are interposed, as shock absorbers, between two or more obj ects .

According to the known prior art, inflatable packaging are made of polymers of the polyethylene type (PE or co-extruded) , so that they are also extremely easy to dispose of.

Envelopes, once inflated, contain a great percentage of air, so that they are extremely light and contribute to reduce transport costs of the packaged goods. Moreover, they are very easy to use: in fact, in order to fasten the load, it will be enough to insert one or more envelopes in empty spaces and inflate them through a suitable inflating valve. Once having reached the optimum pressure, the inflated envelope will immobilize the load, protecting it from impacts or displacements originating from bumps or sudden movements.

These envelopes are normally equipped with a rigid inflating valve applied from outside, of the type of those used in dinghies, which allows them to be closed as soon as they have been inflated. This type of inflating valve is efficient as regards the closure of the air chamber and is used above all in case of many times reusable packaging, these packaging being obviously sturdy enough for multiple uses.

The described packaging however are excessively costly in case of single uses, in which it would obviously be preferable to reduce to a minimum the thickness of the sheets of which they are made.

GB875848A discloses an inflating valve, made of a film of polyethylene or similar material, provided that it is heat-weldable , to be applied through thermal welding to a bag, also made of thermally weldable material, this inflating valve allowing the introduction of an inflating cannula, being it able to afterwards thermally weld it to avoid air leakages.

This type of inflating valve, which is made in order to be able to thermally weld it to the bag, keeping a passage free for the cannula, is surely rather practical and economic to be made; however, the fact that, after inflating it, it is still necessary to thermally weld its edges to obtain its closure, limits its efficiency.

The present invention solves the above mentioned inconveniences by proposing an inflating valve with non ^¬ return function, according to Claim 1, to be used in making inflatable packaging, of the type which provides for a sort of squashed tubular duct adapted to be inserted between the edges of an envelope and joined thereto through a welding, means being provided which are adapted to prevent this welding from generating the closure of the tubular duct, in order to be able to insert into the tubular duct a cannula for inflating the envelope, the inflating valve with non-return function comprising at least two sheets made of weldable polymeric material and mutually joined through at least two pairs of weldings obtained next to the longitudinal edges of said sheets, wherein:

· the first pair of weldings is made in the part of the inflating valve which is affected by the junction with said envelope through said welding;

• the second pair of weldings, which is inserted inside the envelope, is detached from the first pair of weldings, in that there is a non-welded section between the weldings of the first pair and the weldings of the second pair;

the inflating valve with non-return function being spontaneously closed upon extracting the cannula, after having inflated the envelope, thereby making a seal.

As can be seen, the inflating valve with non-return function according to the invention completely solves the above problem, since it allows obtaining the seal with the simple extraction of the cannula, without performing other operations. It follows that its use cost is almost null. The invention will now be described according to a preferred embodiment thereof, and with reference to the enclosed figures, in which:

• figure 1 shows an inflatable envelope equipped with an inflating non-return valve according to the invention;

• figure 2 is an exploded view of the inflating nonreturn valve according to the invention;

• figure 3 shows the inflatable envelope immediately after it has been equipped with the inflating nonreturn valve;

• figures 4 and 5 show the steps for inflating the envelope ;

• figures 6 (a, b) show some variations of the inflating valve according to the invention.

With reference to figures 1 and 2, (1) designates an inflating valve, according to the invention, applied to an inflatable envelope (2) . This envelope (2) is obtained, for example, by performing some weldings (3) along the corresponding edges of two sheets made of LDPE, or materials suitable for this purpose, with the same shape and size. The weldings (3) are made on three sides of the envelope, while the fourth side is kept open to allow inserting the inflating valve (1). The inflating valve (1) is applied to the envelope (2) through a welding (4) which completely closes the envelope (2).

The inflating valve (1) is obtained by mutually joining a pair of preferably rectangular sheets (la) and (lb), for example made of LDPE. According to a preferred embodiment of the invention, this joining is performed through a first and a second pair of weldings (5a) and (5b). Between the due sheets (la) and (lb), a band (6) is inserted, made of plastic material melting at a suitably higher temperature than the temperature at which welding of the LDPE sheets is made, and its property is that it does not adhere to the melted polymers, for example polytetrafluorethylene (PTFE), better known with the commercial name of Teflon, or silicone. This feature is mandatory to keep the inflating valve (1) open when this latter one is inserted into the envelope (2) and welded by performing the welding (4), as shown in fig. 3. It must be noted that the welding (4) affects the area of the inflating valve (1) in which there is the first pair of weldings (5a), so that the second pair of weldings (5b) and part of the first pair of weldings (5a) are completely contained inside the envelope (2) itself.

In practice, a sort of squashed tubular duct is obtained, which is efficiently suitable to be inserted between the edges of the envelope (2) and welded thereto through this welding (4) . The presence of the band (6), which melts and does not adhere to the melted polymer, prevents the two sheets (la) and (lb) from being mutually welded when performing the welding (4), so that, by withdrawing the band (6) after having performed the welding (4), it is possible to insert a cannula (7) between the sheets (la) and (lb) to perform the inflation (fig. 4) .

Alternatively to the PTFE band, other known means can be used, adapted to avoid the welding between the two sheets (la) and (lb) in the joining area to the envelope (2), in order to keep the passage of the cannula (7) free, such as, for example, the local spreading of PTFE or pasty silicone.

According to a preferred embodiment (not shown) , the inflating valve (1) can be made by overlapping also more than two sheets (la) , (lb) .

After having obtained the desired inflation, the cannula (7) is withdrawn (fig. 5) and the inflating valve (1) closes itself spontaneously. The internal pressure (shown by the arrows), which presses onto the sheets (la) and (lb) of the inflating valve (1), makes the adhesion easier, improving the seal reliability.

Figures 6 (a, b, c) show some variations of the inflating valve (1) according to the invention. These variations mutually differ due to the way of performing the weldings between the sheets (la) and (lb) .

Fig. 6a shows the already described inflating valve

(1), which provides for the making of the pairs of weldings (5a) and (5b) next to the longitudinal edges. In the left part, namely the one which is inserted inside the envelope (2) , the weldings (5b) are made, whose features are that they are detached from the weldings (5a), in that there is a non-welded section between the weldings (5a) and the weldings (5b) .

Fig. 6b shows an inflating valve (1') which differs from the inflating valve (1) in that the weldings (5b) reach the front edge of the inflating valve (1') itself, namely the edge which is completely inserted into the envelope ( 2 ) .

Fig. 6c shows an inflating valve (1'') which differs from the valves (1) and (1') due to the presence of other weldings (5b), always made in the part of the inflating valve which is inserted into the envelope (2). Obviously, the further weldings (5b) can be also made next to the edge (not shown) .

Finally, multiple weldings can be made, by extending the section of the inflating valve which is inserted into the envelope (2) (not shown) .

As regards used materials, the sheets (la) and (lb) are advantageously made of LDPE (linear polyethylene) . According to a preferred embodiment, the sheets (la) and (lb) are made of a LDPE-EVA (linear polyethylene ethylenvinylacetate) copolymer, since the addition of the EVA polymer confers a certain "stickiness" to the sheets themselves, which facilitates the seal of the inflating valve .

As clearly appears from the previous description, the use of the inflating valve (1) according to the invention allows extremely easily performing, with rather small costs, inflating and sealing of the envelops (2) . In fact, after having inflated the envelope (2), it is enough to withdraw the cannula (7) without performing any other operation.

The invention has been described as a non-limiting example, according to its embodiments. The skilled person in the art could find other embodiments, all falling within the scope of the enclosed claims.