DE1076786B - Contact device, especially for empty and load switches - Google Patents

Description

GERMAN

The invention relates to a contact device, in particular for empty and load switches, consisting consisting of two parallel switch blades, which are preferably conical in shape when the switch is turned on Mating contact on both sides, namely by means of externally applied pressure means, slide up resiliently.

Empty and load switches are low-voltage switching devices that do not have any noteworthy switching capacities have to deal with. In the case of load switches, the required switching capacity is at most twice that associated nominal current. The main task of these switches is to provide the necessary isolating distances in to establish the circuits. They should not switch off a possible short-circuit current, but with certainty - without being damaged - lead until the associated Circuit breaker has taken over the shutdown. Difficulties with this group of switching devices thus arise in the control of the short-circuit current. As a result of the strong electrodynamic stress In the event of a short circuit, the conventional design empty switches and load switches can become too Contact withdrawals are coming. These contact withdrawals usually lead to serious damage to the Counter. The contacts can weld or be so badly damaged that they are replaced must be, which requires a considerable effort in switches of this type, since the contacts are normally not designed for possible contact erosion.

The arcs that occur when the contacts are lifted can sometimes also lead to arcing to lead.

An important condition to avoid withdrawals is that the current is routed in a straight line over the Contact point, as it has already been carried out structurally for switching devices. With a straight line Current feedthrough is by no means also the forces created by the current constriction on the Contact point arise, switched off. As is known, a further improvement in these ratios is obtained by a parallel compensation of the current forces, in which the current in the switch over two parallel Busbars or switch blades are guided in such a way that there are two parallel contact points, whereby only about half of the total current comes into effect per contact point, the contact force so reduced by a quarter. There is also the fact that the parallel switch blades that are traversed by the current in the same direction, attract each other and so reduce the contact pressure in the event of a short circuit strengthen. Of course, you can't completely switch off the electricity, especially in this way are these also important here,

Contact device,
especially for empty and load switches

Applicant:

Brown, Boveri & Cie. Corporation,
Mannheim-Käfertal, Boveristr. 22nd

Friedrich Heupel, Frankfurt / M.,

and Albert Sotg, Hanau,
have been named as inventors

because the short-circuit currents often take on very large dimensions due to the strong meshing of the networks. The last resort is then to increase the contact pressure again. Anyone However, increases in the contact pressure are due to the space available and the switching mechanism itself and ultimately also by the material used.

The object of the invention is to avoid all of the aforementioned disadvantages. According to the invention is the outward deflection of the contact blades in the ON position of the contact device blocked by a preferably adjustable stop.

The movable parallel contact blades run on a preferably conical counter-contact on both sides, with the contact pressure springs rebounding until the switch blades reach their end position have reached and are then blocked against further deflection. This creates a almost short-circuit-proof contact device created.

An exemplary embodiment of the invention is explained with reference to the two drawings.

In Fig. 1, 1 denotes two parallel contact blades, between which a conical counter-contact 2 is located. A bolt Z ₃ protrudes through both switch blades, on which the contact pressure springs 4 sit outside the switch blades and press the switch blades against the fixed contact 2. Two high spring plates 5 and 6 grip over both springs, which block the suspension in the setting shown,

so that the switch blades 1 cannot be lifted from the fixed contact 2 (i.e. that they are in the Drawing cannot be moved left or right). On the bolt 3 there is also one adjustable nut 7 with which the spring plate 5 so

909 758/380

can be advanced far that just in the end position of the switch blade the spring plate 5 and 6 block the suspension, whereby the stop provided according to the invention is set. the The nut can then be secured against further adjustment. So that the switch blades are in the OFF position are kept at a distance, a spacer 8 is also provided between the knives.

When switched on, the switch blades 1 held apart by the spacer 8 run easily on the conical mating contact 2. Should, as a result of frequent switching (wear on the contacts) again result in a game between the spring plates, so that the spring plate in the ON position of the If the switch is no longer properly blocked, it is easy to readjust the nut 7.

In the example shown, the suspension is arranged symmetrically on both sides of the parallel contact blades. In order not to have to build the device excessively wide due to the projecting springs, it is sufficient It is also possible to arrange the suspension on only one side of the contact blade, with the other side of the Contact knife the adjustable lock nut likes to sit. Also, in many cases, one becomes with one Make do with spring plate per spring, which is then placed directly on the corresponding contact blade.

In the example shown in FIG. 1, a further essential advantage can be achieved by the described Achieve suspensions.

Since it is advantageous to use the double break with empty and load switches in order to Current path will not be able to get a joint (from the movable knife to the fixed connection) according to a further preferred embodiment, the contact blades through corresponding profile holes a switching axis made of insulating material and held without additional fastenings. After plugging in of the individual contact blades in the profile holes, the springs are mounted, which then rest symmetrically on both sides of the switching axis with their spring plates and thereby a shift prevent the contact knife.

An example of this is shown in FIG. Through part of a multi-pole switching axis 9 are two parallel contact blades 1 inserted. In addition, further, free, corresponding profile holes 10 can be seen. The spring plates 5 are arranged symmetrically to the switching axis 9 and rest at the points 12 on this, so that thereby the contact blades 1 are held without having to be additionally attached.

In order to increase the creepage distances, the switching axis is also provided with circumferential elevations 11.

Such a holder of contact blades in switching axes made of insulating material can of course also be used any bolts or split pins are made if other contact pressure media than those described are used will.

Claims (4)

PATENT CLAIMS: 1. Contact device, especially for empty and load switches, consisting of two parallel Switch blades, which, when the switch is turned on, have a preferably conical mating contact on both sides, by means of externally applied pressure means, slide on resiliently, characterized in that that the outward deflection of the contact blades in the ON position the contact device is blocked by a preferably adjustable stop. 2. Contact device according to claim 1, characterized in that the applied externally Pressure medium through a spring (4) and the stop for the contact blade (1) through the associated spring plate (5, 6) are given, where appropriate the stop given by the spring plate (5,6) can be set or adjusted by a preferably secured screw nut (7). 3. Contact device according to claim 2, characterized in that the spring plate (5, 6) a continuous, screw bolt (3) sit, on which preferably a complete compression the spacer (8) preventing the contact knife (1) is located. 4. Contact device according to one of claims 1 to 3, characterized in that the Contact knife (1) through profile holes (10) an insulating, preferably between the individual Phased circumferential, the creepage increasing elevations (11) having switching axis (9) inserted and thereby to open two contacts in series for the current path at the same time or are to be closed, with the spring plates (5, 6) on both sides on the switching axis expediently (9) and thereby prevent the contact blades (1) from shifting. Considered publications:
U.S. Patent No. 2,226,386. 1 sheet of drawings © 909 758/380 2.60