Background of the technique The invention relates to installation technique for electronic devices and concerns an apparatus system, which can be equipped with fan operation. The invention can be used especially in the installation of telecommunication equipment.

Electronic apparatus, such as telecommunication circuits etc., are often installed as centralized into as small a space as possible. Special mounts with ready-made places for circuit boards are often used for installation. When the equipment is used, heat is generated, and it must be conducted off the mount. Conventionally, heat is allowed to be removed passively by conduction, radiation or transmission. If this is not enough, blowing can also be used to intensify transmission.

A typical installation mount for telecommunication apparatus, the so-called ETSI mount, has a main body formed by side walls. The edges of the side walls are bent at right angle inward, whereby they form support and fastening beams. The back wall can be closed or open; in the latter case it is placed against the wall of a room.

Separate installation frames, on which the circuit boards are installed, can be fastened on the beams of the main body in a layered arrangement. The upper and lower levels of the installation frames are perforated, whereby air can pass through them. Room for fastening the cables is often left between the frames on the upper or lower levels of the installation frame. Room for a fan or the like can also be left between the installation frames.

The prior art technique has the problem that fastening the cables on the upper or lower levels of the installation frame is cumbersome work. Another problem of the prior art is the fact that air flow through the frames is restrained, because the cables are fastened on the upper or lower levels of the installation frame. Because of this, points of high temperature are formed at the points where the cables are fastened, and this is harmful for the electronic and telecommunication apparatus. The purpose of the invention is to eliminate these problems.

General description of the invention The present invention is an installation mount according to Claim 1. Some preferred embodiments of the invention are described in the other claims.

A modular cable shelf according to the invention forms a support frame for fastening the cables. The front edge of the support frame preferably also comprises wings for fastening the cables. A modular cable shelf enables fastening cables on the edges of an area above or below the upper or lower surface as seen from the middle of the upper or lower surface of the installation frame. As a rule, the cables are fastened on a wing of the cable shelf, whereby the fastening points of the cables would be outside the upper or lower surface area of the installation frame. The front edge of the cable shelf preferably also includes an opening, through which installation work can be carried out in the rear parts of the frame. Thus the cable shelf enables a freer air flow through the support frame and prevents the formation of harmful points of heat in connection with fastening to the installation frame.

Drawings The accompanying drawings illustrate an installation mount according to the invention.

Figure 1 shows an installation mount for telecommunication apparatus directly from the front.

Figure 2 shows an installation frame of the installation mount diagonally from the front.

Figure 3 shows a cable shelf according to the invention diagonally from the front.

Detailed description of an embodiment of the invention The so-called ETSI mount according to the figures comprises a main body formed by the side walls 1 and 2. The edges of the side walls are bent at right angle inward, whereby they form support and fastening beams. The back wall is open, and it is placed against a wall of the room.

Four frames 3 are fastened on the beams of the body in a layered arrangement. Each frame is connected with a cable shelf 4,4'on the upper and lower level. There is a fan unit 5 between the first and second and the third and fourth compartment.

Between the second and third compartment, there is an air guide 6 and above the

topmost compartment another air guide 6'. Above the upper air guide, there is a connection and control unit 7.

The frames 3 (Fig. 2) have a grating floor and roof, through which air can pass.

Circuit board units are fastened on the rails vertically next to each other. An air gap remains between the circuit board units. On the side edges of the levels, there are side walls 8 of the height of the shelf space formed by the compartment.

The fan unit 5 comprises a fan, by means of which the air flow through the frames can be intensified.

The cable shelf 4/4' (Fig. 3) comprises a front wall 9, side walls 10 and 11 and a back wall 12. The front wall is provided with a projecting part 13. The shelf is fastened to the beams of the side walls 1 and 2 of the main body. There are through holes 14 for the cables on the side walls of the shelf. There is also a cut-out 15 on the lower part of the walls on the front ends of the side walls and the side ends of the front wall. The cut-outs can be covered with a screen 16 (see Fig. 2) formed of vertical strips and fastened to the front wall of the shelf. There is an opening 17 in the middle of the front wall. A bottom level 18 projects out from the mid-part of each part of the front wall to provide the bottom for the projecting part of the cable shelf. The front part of the bottom level extends to the sides, but leaves a suitable space for the installation of cables in front of the cut-out. The front edge of the bottom levels is bent upwards to form the front wall 19 of the wing of the cable shelf. There are fastening slots for cables on the front wall. The slots are diagonally downwards, their upper end is wider and their lower end has an extension upwards.

The opening of the front wall of the cable shelf is covered with a detachable cover plate 20, which is fastened to the edges of the opening. The cover plate is a knee- piece, which is also fastened to the parts of the bottom level of the wing of the cable shelf. The cover plate has an aperture 21 for the service and management bus 22.

The projecting part 13 of the front wall of the cable shelf 4 of the lower level of each frame 3 is upwards and the projecting part 13'of the upper level 4'is downwards.

Each frame 3 is also covered with a detachable cover plate 23. The cover plate is fastened with quick-release locks having spring-like tongues fastened to the side walls of the mount, which attach to the counter-holes on the edges of the cover plate.

The fan unit 5 sucks air through the installation compartment 3 below and blows it through the compartment above. Due to the solid wings 13 of the cable shelf, the side walls 8 of the frame and the wall behind the installation mount, air is efficiently guided through the installation compartment above. In a corresponding manner, the air that has passed through is removed from the compartment through the middle aperture formed by the front wall of the air guide 6.

Compensation air flows to the lowest frame 3 through the base of the installation mount. The upper fan unit 5 again takes air from between the side walls of the mount and the installation compartment and in front of the mount from the top of the knee-pieces 21 of the air guide 6 to the top of the upper surface of the air guide, from where it flows into the installation compartment above.

The cabling work is easy to carry out according to the invention. In addition, the cooling air is efficiently guided where it is needed. Due to the modular construction, the system is flexible.