DE6800461U - EXPLOSION PROTECTION FOR THE LIGHTING DEVICE OF A SCALE - Google Patents

Description

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PATENT LAWYERS

HELMUT SCHROETER KLAUS LEHMANN

DIPL.-PHYS. DIPL.-INC. β MÖNCHEN 25 · LIPOWSKYSTR. 10

G 68 OO 461.5 8 <ir-31g 7 / H / l

Sartorius-Werke GmbH. 11] .8.1969

L_ Explosion protection device for the lighting device one

The invention relates to a Explosionsschutzeinrich · * processing for the illumination device of a balance, especially for a scale-projection device.

When using scales with lighting devices in potentially explosive areas, it is necessary to use the Teix «of the lighting device so that no sparks with the potentially explosive atmosphere in Contact and that no temperatures that go beyond a certain MaA.

Parts are commercially available that comply with explosion protection regulations, but are so bulky that m put them in a normal balance housing, e.g. for precision and precision scales, can no longer be built in, but must be set up next to the scales and thus the Narrow the workplace.

According to the invention, this disadvantage is avoided by that the lamp of the lighting device is housed in a protective housing arranged in the balance housing is that to supply the lamp in the balance housing a voltage-reducing scatter transformer is arranged and that an explosion protection switch is installed in the balance housing.

5800461

Postal check account 1679 41 Munich · Deutsche Bank, Munich Account 70/37 369 ■ Telephone: (08 11) 77 89 56

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By arranging the components in the scale housing itself, space is saved outside the scale, i.e. the workplace is not restricted. In addition, the one-piece device created by the invention is easier to transport than a scale with separately installed explosion-proof parts, namely transformer and switch. By using a Streutranformators the temperature is ensured _s that even in the case of a secondary short circuit can not accept a potentially dangerous level. The high leakage flux ensures a high leakage resistance in the event of a short circuit, which limits the primary current to such a level that the transformer does not heat up above a limit temperature specified as permissible.

In a further development of the invention, a limit switch with snap contact, which is located in the balance housing, can serve as an explosion protection switch is mounted in drive connection with the locking device of the balance, in particular its switch plunger is in engagement with a cam disk of the locking shaft of the balance "

By using the snap contact, the two poles of the switch are moved quickly over a large distance so that no arcing can develop. By placing the switch in driving connection with the locking device of the scale, which means so ₅ that it is actuated by the locking shaft of the scale, it is achieved that the illumination device when locking of the scale is inevitably turned off. There is therefore neither a separate operation of the switch required, nor is there a risk of the lighting device inadvertently leaving the lighting device switched on, as a result of which a

5800461

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such high temperature would develop that later weighings would be heavily counterfeited.

It is known per se (US-PS 1.65 3.OH3), by a a manually operated locking shaft of a balance To operate a toggle switch to switch a lighting device on the balance on and off. But here you have to pay attention Care must be taken that the arm of the toggle switch cannot be broken off, including an elastic eccentric ring is required, but not sufficient operational reliability, in particular guaranteed over longer periods of time. In contrast, the use of a limit switch with Jump contact is more reliable and easier to use, which can be achieved, for example, by using a cam disk on the Locking shaft can happen.

In a further development of the invention, a reducer for adaptation to a A lamp suitable for scales with a low power consumption and a short filament should be provided.

This gives you the option of using lamps with short filaments that are suitable for scales, i.e. approximately point-shaped lamps Light sources that are necessary for a good image. In addition, within the balance is due to low Power consumption generates less heat, so that the weighing results are not caused by excessive heating of the balance be faked.

An embodiment of the invention is described below with reference to the drawing.

Fig. 1 shows a view, partly in section, an explosive

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Protected lighting device according to the invention, housed in the rear lower part of the housing a precision or fine balance, with part of the housing wall broken away. Fig. 2 shows the associated circuit diagram.

The leakage transformer 3 is attached to a chassis 2 of the housing 1, with the limit switch serving as a switch on the left 5 with snap contact. The switch is operated by a cam disk that is fixedly attached to the locking shaft 7 of the balance 9 actuated.

Above the scatter transformer 3 is the protective housing 11 mounted for the lamp 13 in the balance housing. The protective housing has a lamp socket 15 into which the reducer 17 is inserted, which receives the lamp 13.

A cable entry 18 in explosion-proof design is attached in the rear wall of the balance housing. A three-wire Power supply cable 19 is inserted through line entry 18 into the housing and there, as shown in FIG. 2 shows, connected to the switch 5, the leakage transformer 3 and a metal part 21 of the scale frame. One Line 23 leads upwards in the balance housing and into the protective housing 11 of the lamp 13.

Claims (1)

-5- sar-31g 7 / M / l August 12, 1969 PROTECTION APPROACH Ι «Explosion protection device for the lighting device a balance, especially for its scale projection device, characterized in that the lamp (13) of the lighting device in one in the balance housing (1) arranged protective housing (11) is housed that for supplying the lamp in the balance housing a scatter transformer (3) reducing the mains voltage is arranged, and that in the scale housing an explosion protection switch (5) is attached. ο explosion protection device according to claim 1, characterized in that a T 'dtaster serves as explosion protection switch (5) with spring contact mounted in the balance housing (1) in driving connection with the locking device of the scale _s and in particular, its switching plunger is in engagement with a cam (9) the locking shaft (7) of the balance. 3. Explosion protection device according to claim 1 or 2, characterized in that within the protective housing (11) of the lamp (13) a reducer (17) is provided for adaptation to a lamp suitable for scales with low power consumption and a short filament. -pÄÄ from the word enhancement de, submitted documents are »ioS in den Amliokten 's £ kannM & erVeit oh? JN _n ΐ"'"'*' ^α ""1% J **» «PrOnglidi a SiS jar "- ^will · ^{On requests, kJÄ} ^ ÄfeÄ VA ¹ A ⁰ A: .on uiMoj iuaon Dsnnoen > icn in the Aintii can be viewed. Will be upon request (6 69 \ ■ "■ -" ^w "" * · "" wuiiumn rreisen delivered Oeutidie · Patent Office, O »breudi» murt «rHe! L ·