The present invention relates to an envelope for forwarding letters and the like, and of the type described in the introductory part of claim 1.

Envelopes for forwarding of letters shall according to the law keep some minimum deo- mands, for instance it may be demanded, that an envelope not just may be opened and re-locked, without to be noticed.

Many envelopes of the mentioned type are provided as socalled self-adhesive with closing flaps with glue surfaces, which may be connected by folding together, as a latex-based type of glue preferably is used. However, this results in a poor sealing of the envelope, that is that it may be opened and re-locked without any marks.

The authorities and private companies, for instance financial institutions use more and more automatic envelope filling apparatuses for packing of periodic letters, for instance statement of accounts from financial institutions and the like. By means of modern auto¬ matic envelope filling apparatuses letters may be folded and inserted in envelopes, which then are closed and preferably sealed by means of the glue surface of the closing flap.

In connection with automatic envelope filling apparatuses envelopes with only one closing flap are used, which flap at basis often has a folding line in the form of a perfo¬ ration, as the closing flap hereby is easier to fold mechanically for closing of the envelope. The closing flap is provided with a glue surface of "moisten glue", that is a type of glue, which in order to catch has to be moistened with water, and which gives a safe sealing of the envelope.

The purpose of the invention is to provide an envelope of the type described in the in¬ troductory part, and by means of which further advantages in the use may be added.

The envelope according to the invention is distinctive in, that the closing flap between the glue surface and folding line is provided with a perforation stretching parallel to the free end edge of the closing flap, and that the envelope along a second closing flap adapted to be glued together with said first closing flap is provided with a second per- foration stretching parallel to said first perforation. In a simple manner it is hereby obtained that a new type of envelope, where the closing flap is provided with a reinfor¬ ced tear-open strip, which between the perforations consists of at least to layers of paper, so that the envelope is easy to open in such a manner, that easy direct access for emptying the envelope is obtained.

Preferably the envelope is such provided, that said first perforation is provided close along the glue surface of said first closing flap, and that the second perforation consists of a folding line for said second closing flap, which is provided with glue of a type being able to co-operate with the glue surface of said first closing flap.

Appropriately the envelope is such provided, that said perforations are mutual parallel and that the distance between said perforations is some 5 to 30 mm, preferably about 10 mm.

The invention is described in the following with reference to the drawing, in which:

Fig. 1 shows an embodiment for an envelope - seen from the back and with the closing flaps folded in,

Fig. 2 shows the envelope cf. Fig. 1 - seen from the back and with the closing flaps unfolded,

Fig. 3 shows the envelope cf. Fig. 1 - seen from the back and closed by folding to¬ gether the glue surfaces of the closing flaps,

Fig. 4 shows a sectional view of a modified embodiment of the envelope cf . Fig. 1 , where the tear-open strip is provided with a grip-tongue, and

Fig. 5 shows, how the envelope cf. Fig. 4 is opened by means of the tear-open 5 strip or the grip-tongue.

The envelope 2 shown in Figs. 1 - 3 comprises a pocket part 4 and a first closing flap 6, which on the inner side is provided with a glue surface 8 of a glue type being adapted to catch with a glue surface 10 of a second closing flap 12, that is that the envelope

10 preferably is socalled self-adhesive. The closing flap 6 is between an upper folding edge or line 14 and the glue surface 8 provided with a transverse perforation 16. A folding line 18 between the second closing flap 12 and the pocket part 4 also consists of a trans¬ verse perforation, so that - between the perforations 16 and 18, when the envelope 2 is closed during folding the closing flaps 6 and 12 (Fig. 3) - a reinforced tear-open strip

15 20 consisting of two layers of paper glued together is formed.

Fig. 4 shows, how the closing flap 6 in front of the tear-open strip 20 is provided with a grip-tongue 22, which as shown in Fig. 5 is used for the gripping in order to open the envelope 2 by tearing off the tear-open strip 20. In practice the grip-tongue 22 may 20 rather not project over the short sides of the envelope.

To avoid breaking the tear-open strip 20 during openening of the envelope 2, the perfo¬ rations - as per se known - may comprise inclined sheeter lines, which secure correct break direction by tearing off the material between the perforations 16 and 18.

25

The main aspect of the invention - safe tearing open of an envelope - may be obtained in other manners, as the tear-open strip of the envelope might be found in the sides of the envelope, where the tear-open strip also might consist of two layers of paper glued to¬ gether.

An envelope according to the invention might comprise two closing flaps, of which the first flap is provided with a strong adhesive glue surface, which temporarily is connec¬ ted with a silicone coating, which along the closing flap is applied to the outside of the envelope. The second closing flap, which - if the occasion should arise - might comprise said tear-open strip, does not need to be provided with glue surface. When the envelope has to be sealed, first said closing flap is loosened from the silicone coating, whereafter the envelope is closed and sealed effectively by folding together the closing flaps.

Of course it will also be within the scope of the invention, that only one of the closing flaps is provided with a glue coating, for instance a strongly acting moisten glue.