BACKGROUND OF THE INVENTION

The present invention relates to enclosures for electrical equipment which are used to secure the contact-protection and to protect electrical equipment from environmental influences. For example, an encapsulated electric motor safety switch to prevent an accidental start-up during the maintenance work has to be placed on an electric motor in the immediate vicinity. In particular, the metal structures, such as sheet steel enclosures easily moisture condenses inside-age to. If the condensed water is not drained from the enclosure, the water may cause interference with any electrical device, at worst, a short circuit. The easiest way is to arrange one or more of a small hole in the bottom of the casing, so that condensed water can freely cast-off of the chassis. There are also available such as a plastic cap which can be printed on the hole punched on the bottom of the casing, and which has a groove or channel arranged for discharging water from the enclosure.

These solutions exhibit such a problem that, at least in the process industry machinery and equipment often need to be cleaned by water jet, in which case such as enclosed switches can be bottom oriented can-meter generates a strong jet of water in and then the water can suddenly be inside the case clearly a number, which leads to immediate problems.

Humid environmental conditions, housing protection class should be at least splash-waterproof IP44, where the first number indicates that the enclosure is protected by a very small pieces with a diameter of more than 1 mm larger accessing in the and the latter number indicates that the housing is protected against splashing water.

BRIEF DESCRIPTION OF INVENTION Invention is to achieve a housing arrangement which solves the above problems. This is achieved by the said invention. The invention is characterized in what is carried out in the independent claim 1. Preferred embodiments of the invention are descriped by the dependent patent claims. The present invention is based on the structure of a housing lower part; preferably the bottom wall is pierced by at least one hole, through which a fastening device such as a bolt which holds the opening on the housing exterior and interior surface such toothed washers that form the channels allowing-the condensate dripping out of the housing. Bolt is equipped with a nut to tighten the arrangement to a torque that the teeth do not sink on the housing surface preventing the water route out of the case.

The invention is particularly advantageous in that it can be used to achieve the mass-produced standard components.

BRIEF DESCRIPTION OF FIGURES

The invention will be described in detail with respect to preferred embodiments, with reference to the drawings in which

Figure 1 shows the electrical equipment enclosure;

Figure 2 shows a cogged washer;

Figure 3 shows the arrangement in accordance with the present invention;

Figure 4 shows a bolt equipped with a flange with locking teeth; Figure 5 shows a nylon-locking flange nut;

DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows an enclosed switch, which is intended for installation in the field and can therefore be subjected to demanding environmental conditions such as cleaning the process equipment by water jet. The housing is typically made of steel sheet, and the water can be condensed in due to temperature variations. The steel plate is typically 1 ,5 - 2 mm in thickness. The housing may also be manufactured of light metal such as aluminum, or plastic. In this case, the wall thickness of the steel is often much greater than used in the disc housing.

Figure 2 shows a cogged washer, which is conical and on the convex side scored rough and another side is provided with a couple of teeth 6, typically about four to six units. Nomel ® locking washer represents such a commercial product. Fig 3 shows the invention arranged on the enclosure according to Figure 1. The housing bottom wall is pierced by a hole 2. The bolt 3 is assembled through the hole 2 and holds by the nut 5 the cogged washers 4 in their position on both sides of the housing wall. A cogged washer is installed so that the teeth 6 are against the wall of the housing, when a channel is composed for draining the water out of the housing. The hole 2 must be broad enough, so that a sufficient channel between the bolt and the hole edge remains for draining the water out. Particular in a case that the housing material is softer than the mounting arrangement, it should be observed that no inserts can be tightened too much, so that the teeth 6 of the washer bite into the wall of the housing blocking the water channel. For soft materials the bolt is recommended to be surrounded by a sleeve, which length is that much greater than the thickness of the wall of the housing that the nut is prevented to be tightened too tight so that the teeth 6 are not going to enter the wall of the housing. In particular, replaced the bolt by a pull-rivet, for example by a so-called "pop rivet", you can not itself determine the tight- ening torque, then the sleeve securing that the serrated washers 4 shall remain at a suitable distance from each other and not going to enter the housing wall in 1.

Nut 5 is preferably a nylon lock nut so that it can be safely left on loose enough, it still does not become detached by vibrations and the tightening torque is maintained at the right cogged washers 4 with a suitable pressure against the housing wall 1.

The cogged washer 4 flange diameter should be well larger than the hole of the wall so that especially the washer outside of the housing can effectively protect splash of the penetration of water inside the casing and preferably a similar washer ais used inside the housing, in which case direct orientation of the water jet to the up- per parts of the housing and electrical circuits mounted there is blocked.

Inside the enclosure other types of transparent base plates or the teeth up to a traditional spring washers can be used, but failing to achieve a good protection of a water jet for the most demanding applications.

Often one of the above mentioned arrangements is sufficient to lead the condensed water out for the cabinet, but more than one can be fitted into one housing, as well. Using at least two, the air circulation is obtained for the housing improving electronic equipment cooling. Depending on the housing volume and operating conditions different sizes of bolt-washer combinations may be selected.

Fig 4 shows a flange-bolt 7, which flange has a dense cogging. The bolt 3 and the outer washer 4 can be replaced by a flange-bolt 7. Fig 5 shows the nylon lock nut 8 having a dense cogging correspondingly with a flange-bolt. Inside the casing the cogged washer 4 and a locking nut 5 can be may be replaced by cogged flange-nut 8 . Flange-nut 8 may be used either for the normal bolt 3 and an outer toothed washer, or 4 with the flange-bolt 7, such as the flange-bolt 7 can respectively be used in various types of internal side of the nuts and washers.

The above-described embodiments are not intended to limit the invention, but rather only to clarify the basic idea of the invention. It is quite clear that the details may vary within the framework of the claims. May differ from the shape of the housing shown in Fig 1 , but it is essential to place the dewatering arrangement lower than the electrical equipment within the housing, preferably to the lowest point of the housing.

The invention is not limited to the housing, from any of the switches, but the invention can be used in numerous applications where the corresponding housings are used.