DESCRIPTION OF PRIOR ART Previously known vent devices for. providing air discharge from a space inside. a building typically includes a ventilation pipe, which debouches in a wall, for example in a kitchen or in a wet space, said pipe terminating with a pipe portion.

Inside this pipe portion a vent unit is fastened, having means for engagement with a pipe portion, whereby spring acting support loops or hook plates could be mentioned. The vent unit has a conical portion, which comprises a conduit portion and a valve body, which is axially movable with respect to the conical portion.

Adjustment of the valve body in an axial direction results. in a higher or lower degree of throttling the vent unit. For that purpose the valve body may be adjustable over external manoeuvring means allowing adjustment with the vent unit in position, or simply be carried by the screw, which means that the vent unit must be taken out from its position in order to be adjusted. When applying the vent device in rooms having inner ceilings there may be alternative pipe installations and fastening for the pipe portion.

Vent devices of today suffer from disadvantages because they are complicated to install, and in certain cases also to remove. The known mounting elements, support loops and hook

plates, often provide insecure fastenings that are difficult to handle and sometimes, again, vent units that are stuck in place risk damaging surrounding details when they are to be removed. Further, today's vent devices demand assembly of plural details and are therefor relatively expensive.

AIM AND MOST IMPORTANT FEATURES OF THE INVENTION It is an aim of the present invention to provide a vent device and a vent unit of the kind mentioned above, wherein the problems of the prior art are avoided or at least reduced. It is also an aim to provide a manufacturing-friendly and easy handled solution, which altogether gives the possibility to achieve low cost for manufacture as well as for mounting in a ventilation system.

These aims are achieved in a device as above through the feature of the characterising portion of claim 1.

Hereby it is possible to provide a vent device, which is simple to manufacture, easily handled and easily mounted. By making use of co-operating snap-lock means and snap-lock- elements simple production of the vent unit as well as the pipe portion is enabled. Further, safe engagement between the details may be achieved using means that are easily produced.

This results in the possibility of safe and easy establishment of the engagement as well as loosening of this engagement.

It is preferred that the vent housing is a plastic detail and that the snap-lock means are integrated on the outside of the conduit portion. Hereby the manufacturing-friendliness and the easy-to-handle properties of the device are accentuated.

In a further preferred embodiment the snap-lock means are discrete means, which are distributed in the circumference direction over the conduit portion, and which co-operate with snap-lock elements, which are equally discrete elements arranged with a certain mutual distance. Hereby it is possible to achieve unfastening between the vent unit and the pipe portion very simply, which is an important advantage, since the engagement force does not have be reduced in order to enable unfastening. Unfastening is simply made by turning the vent unit until free removal is possible.

In a further preferred embodiment a plural (at least two) snap-lock means are arranged separated in the inserting direction so as to allow locking with different degree of insertion of the vent housing with respect to the pipe portion. This is an essential advantage, since the precision when mounting the pipe portion inside the wall may be reduced.

Further, a certain mutual obliqueness between the pipe portion and the vent unit may be accepted and still good contact of the vent unit against a wall be achieved.

A further advantage with constructing the snap-lock means such that alternative fastening in the insertion direction is allowed is that tolerance demands in manufacture of the parts does not have to be very great, since the desired engagement is possible to obtain also if there is a certain dimensional deviation. This is an important advantage with locks of the kind used here.

The presence of guiding wings outside the conduit portion gives possibility of desired guidance between the details.

By also the pipe portion being a plastic detail having integral snap-lock elements, the manufacturing friendliness of the device is further accentuated.

In a particularly preferred embodiment of the invention the pipe portion has a sealing lip which in the inserted position of the vent housing engages and seals against the outside of the conduit portion. This solution provides a direct seal through the engagement between the pipe portion and the vent unit making a further sealing ring or the like unnecessary.

In particular it is preferred that the sealing lip is an essentially axially directed integral part of the pipe portion. This enhances manufacturing friendliness and economy and simplifies. assembly of the device. Further, there is no risk of forgetting an essential element when assembling, which could otherwise result in leaking air currents. This solution further provides a safe seal, which is not dependent on the engagement of the vent unit against in building inner wall.

Further, important advantages are achieved through further aspects of the invention, which will be apparent from the following detailed description of embodiment.

SHORT DESCRIPTION OF DRAWINGS The invention will now be described in detail at the background of embodiments and with reference to the annex drawings, wherein: Fig. la shows in an axial section a part of a vent unit according to the invention,

Fig. lb shows the part in Fig. la in a view from the right, as seen in Fig. la, Fig. 2a shows a pipe portion being included in a device according to the invention in an axial section, Fig. 2b shows the pipe portion of Fig. 2a in view from the left, as seen in Fig. 2a, Fig. 3 shows a device according to the invention in an assembled, mounted state, and Figs. 4a and 4b show in detail the region of the snap-lock and the seal between a vent unit and a pipe portion according to the invention.

DESCRIPTION OF EMBODIMENTS In Fig. la, number 1 depicts a vent housing of a vent unit, which is included in a device according to the invention. The vent housing 1 includes an essentially conical conduit portion 2, which is intended to be inserted into a pipe portion, and an outside portion 3 which is intended to lie against an inner wall, a roof panel or the like with its rear surface 31. On the outside of the conduit portion 2, the vent housing 1 is provided with a number of locking knobs 4 which comprise snap- lock means, and which are intended to co-operate with corresponding elements in a pipe portion in a way that will be described later. Further, on the outside of the conduit portion 2 the vent housing 1 includes guiding wings 5 having an axially directed guiding surface for guidance into said pipe portion, and having an oblique surface 5'corresponding to the cone angle of the conduit portion 2. The guiding wings 5, which are distributed over the circumference of the conduit

portion 2, hereby allow stacking of a number of vent housings into each other with maintained stability.

The vent housing 1 further has a support 6 for a valve body, which is not shown here, and which completes the vent housing so as to form a vent unit. The support 6 has a central thread and a number, here three, (see Fig. lb) holder arms. A not shown valve body having a threaded stem may thus be screwed into the support 6 so that an adjusted throttling of the air is achieved through the resulting vent unit.

In Fig. lb, the vent housing is seen from the right in Fig. la wherein the snap-lock means 4 are shown, here shown separated into two groups, 4a and 4b. The first group of snap-lock means or locking knobs 4a are positioned on a smaller radius and thereby at a shorter distance from the thin end of the conduit portion, the end to the right in Fig. la. The second group snap-lock means or locking knobs 4b are thus positioned axially at a greater distance from the thin end of the conduit portion 2 and on a greater radius of the conduit portion. The reason for this is to allow locking in two levels of the vent housing 1 in a co-operating pipe portion. It is also possible to achieve angular deviation of the vent housing with respect to a pipe portion by only having any of the snap-lock means 4a, b in each group being active so as to allow adjustment to an inclined wall or an obliquely inserted pipe portion.

In Fig. lb, supports 7 for insertion of hook plates for conventional insertion of a vent unit having a vent housing 1 in a conventional pipe portion is also shown. This contributes to the versatility of the invention.

In Fig. 2a, 8 concerns a pipe portion for insertion into a ventilation channel, which is intended to open in a space inside a building. The pipe portion 8 includes a tubular connection portion and a flange 9 for lying against the mouth side of the wall. Over its end side the flange 9 is provided with distributed protective ears 10 having such an axial extension that they protrude outside the sealing lip 11. The protected ears 10 also function as handling aids for a person mounting the pipe portion into a wall. The sealing lip 11 which is comprised of a thin, ring-shaped protruding portion is intended, in use, to sealingly engage the conduit portion of the valve housing, and in particular the outside thereof, above the. snap-lock means 4a, b (see Fig. la and lb).

The pipe portion 8 is further provided with an entering chamfer 12 on its inner side, inside said sealing lip 11, which entering chamfer 12 axially inwards transforms to snap- lock elements 13 in the form of a distributed, circumferentially positioned snap-lock edge. This edge is intended in use to co-operate with locking knobs 4a, b of the vent housing (see Figs. la and b). The locking edge is, however, interrupted at 14 of a number of distributed free areas, which as a regards width, number and distribution corresponds to the locking knobs 4a, b of the vent housing. In operation these free areas 14 will allow free removal of a vent unit from a pipe portion 8 when the vent unit has been rotated in order to achieve alignment between the locking knobs and said free areas 14.

The parts of the pipe portion are shown in greater detail in Fig. 2b with the distributed protective ears 10 on the axial surface of the flange 9 and the position of the free areas 14 over the inside of the pipe portion 8.

In Fig. 3, the device according to the invention is shown in an assembled state, having the vent housing shown inserted into the end of the pipe portion 8, and with the sealing lip 11 sealingly engaging the outside of the conduit portion 2 of the vent unit. A locking ring 15 is in the shown assembly used to provide an application force at the rear side of a panel into which the pipe portion 8 is inserted. In order to co- operate with the locking ring 15, the pipe portion has a number of shallow, axial ridges distributed over the outside of its tubular portion. The pipe portion may of course also be plastered into an integrated ventilation channel in a wall. In a usual, here not further explained manner, a valve body 17 is arranged axially moveable in the vent unit.

In Figs. 4a, b the engagement area between the vent unit and the pipe portion is shown in an enlarged scale. Fig. 4a concerns the engagement of the snap-lock element with a locking knob from the first group, 4a. Fig. 4b concerns the engagement of the snap-lock element 13 with a locking knob from the second group 4b. The sealing engagement of the sealing lip 11 against the outside of the conduit portion 2 is also shown.

The invention may be modified within the scope of the annexed claims and thus the snap-lock means and the snap elements may be constructed inverted, with the means made as recessed portions and the elements as protruding'portions instead of what is shown. Also otherwise the snap-lock means may be constructed differently, for example as continuous circumference means and edges. In that case, however, the design must be such that loosening between the details may be achieved without the possibility of rotating one of the parts in order to achieve freeing from the snap engagement.

The vent device is here described as an air discharged device, but it should be understood that use as an air supply device is within the scope of this invention.

It is preferred that details according to the invention include all the described elements, but it is of course not excluded that some of the non obligatory elements are left out, even if the corresponding advantages are not achieved.