DE1042755B - Safety device for systems with high-voltage fluorescent tubes, especially illuminated letters - Google Patents

Description

GERMAN

It is already a safety device for electric fluorescent tubes operated on transformers known in which in a special earth fault connection within the secondary circuit of the transformer a special spark gap is provided, in the area of which a spark gap occurs when the spark gap is triggered Fusing wire is arranged, which one in the primary circuit of the transformer The lying safety switch controls and thus the transformer when the spark gap is triggered automatically disconnects from the network.

The invention relates to a safety device for systems with high-voltage fluorescent tubes (Neon tubes), in particular systems for writing or drawing neon light, their Fluorescent tubes arranged next to one another and progressively in places by lifting a bridging of the contact path of an auxiliary switching device are made to light up by means of a movable contact rail.

In general, such systems work periodically. The contact rail and the contact track are then Circular arc-shaped, and the contact bar is around the center of curvature of its circular arc shape turned.

Every time the contact bar runs away from a contact on the contact track, there is a power interruption in a branch of the high-voltage circuit, the sparking of the strength of the interrupted Current and the size of the voltage depends. Sparking is harmless when there is a current path exists parallel to the interruption line. However, if such a parallel current path is not available, What if a circuit error, for example due to unnoticed loosening of a contact screw, a Ingress of air into a neon tube or failure of a tube can be the case, so must be the drain the contact rail of the contact path the full current of the high-voltage circuit can be interrupted. As a result, an arc that does not extinguish itself can form at the contact point. which means a considerable risk because such a standing arc can destroy the switching device and possibly lead to a greater spread of the fire. A standing arc is all the more dangerous than it can occur in the case of a disturbance of the kind mentioned without being noticed at first.

The main purpose of the invention is to provide a safety device to create in the event of a possible electric arc to trigger a safety switch is used, which puts the system out of operation and thus eliminates the impending danger.

The special feature of the safety device according to the invention is that along the contact safety device for plants

with high-voltage fluorescent tubes,

in particular illuminated lettering systems

Applicant:

Moveri Lux Leuchtröhren GmbH,
ίο Hamburg 36, Gänsemarkt 44

Hans Friedrich Harald Weidemann, Hamburg,
has been named as the inventor

track a burn-off or fusible link isolated from this and the contact bar, which is known per se Way controls a safety switch in the primary circuit of the high-voltage transformer, at such a distance is arranged by the contact track that it is in the effective range of one of the contacts about occurring standing arc is located.

An embodiment of the safety device according to the invention can consist in that the burn-off or fusible link through a thread made of a plastic, preferably made of a polyamide (»Perlon«, "Nylon" or the like) is formed. Such a thread has the particular advantage that it and is weatherproof and that in particular its length at the tensile force to which it is subjected, of Is independent of the influence of moisture.

When exposed to an arc, such a thread is reliably and quickly interrupted, so that the safety device puts the system out of operation.

The invention is explained in more detail below with reference to the drawing, for example.

In the drawing, the circuit arrangement of a system with a safety device according to the invention is shown schematically, for example. 1, 2, 3 denote a system of high-voltage fluorescent tubes that complement each other to form the letter N. Each fluorescent tube is subdivided by intermediate electrodes, the connections of which are led to a contact track 4 which, in the state shown, is bridged by a movable contact rail 5. Each individual section can also be formed by a special fluorescent tube. The adjacent ends of the high-voltage fluorescent tubes 1, 2 and 2, 3 are connected to one another. The free ends of the tubes 1 and 3 are connected to the high voltage winding

SM 677/180

of the transformer 7, the low-voltage winding of which can be fed from an alternating current source RO via a main switch 6, a safety switch 8 and an on / off switch 9. The safety device, which is designated as a whole by 10, essentially comprises a burn-off or fusible link, preferably a plastic thread made of a polyamide, and the safety switch 8 with the opening spring 12 connected for switch 9. The main switch 6 is inserted for commissioning. The tube system 1, 2, 3 is initially dark. Xun the contact bar 5 is moved together with the control cam 13 in the direction of the arrow. The switch 9 is closed, so the transformer is switched on. As a result, high voltage is applied to the fluorescent tube system, which is for the most part bridged by means of the contact rail 5. The unbridged first fluorescent tube section on tube 1 on the left-hand side is made to light up in this way. The remaining sections are bridged by the contact rail. When the contact bar is continuously moved on, the short circuit of the individual contacts of the contact track 4 is progressively eliminated. This causes the following sections of the fluorescent tube to light up in places.

Are the contact rail and contact track formed in the shape of a circular arc and the contact rail is around rotated the center of curvature of their circular arc shape, such systems can be known per se Way work periodically so that the entire, represented by the fluorescent tube system Lettering or the like switched on progressively in places and then suddenly or gradually again is switched off, whereupon the work cycle can begin again.

When working properly, every time the left end of the contact bar 5 makes contact leaves, only an insignificant current interrupted at the contact point, since immediately the one to the contact path parallel fluorescent tube section is ignited and takes over the current conduction. Has however, for example, the connection connection of an intermediate electrode is loosened or is different A circuit fault occurred, as a result of which such a parallel current path is not present, should the entire current of the high-voltage circuit can be interrupted at the relevant contact point. this is generally not easily possible. Rather, a standing arc would form, which leads to Lead scorching of the contact device and would also result in a fire hazard. This risk is avoided by the safety device according to the invention, since the Abbrennoder Fusible link 11, which extends along the contact track 4, in the area of the action of a such arc lies and is immediately destroyed by the arc, so that the switching element of the safety switch 8 by the switching spring 12 instantly in the switch-off position is performed. This interrupts the low-voltage circuit and the system put out of service.

It is thus readily apparent that the invention provides a fuse for systems with fluorescent tubes, in particular Leuchisioffanlagen, is created, the task mentioned at the beginning fully corresponds. The safety device according to the invention is also suitable for more extensive systems Suitable for high voltage fluorescent tubes. The safety switch can be designed with two or three poles and, if necessary, several safety devices can also be used in a system have several burn-off or fusible links and / or several safety switches are present be.

Claims (3)

Patent claims: 1. Safety device for systems with high-voltage fluorescent tubes, which progressively in places by removing a bridging of the contact path of an auxiliary switching device by means of a movable contact rail are made to light up, in particular illuminated lettering systems, characterized in that one of this and the contact rail along the contact track insulated burn-off or fusible link that has a safety switch in a manner known per se controls in the primary circuit of the high voltage transformer, at such a distance from the Contact track is arranged that it is in the area of action of one of the contacts about occurring standing arc is located. 2. Safety device according to claim 1, characterized in that the burn-off or Fusible link consists of an electrically insulating material. 3. Safety device according to claim 2, characterized in that the burn-off or Fusible link is formed by a thread made of plastic, preferably a polyamide. Considered publications:
German patent specifications No. 582 213, 664205. 1 sheet of drawings © 809 677/180 10. 5t