DE397620C - Switching device in which an insulating body is inserted between the contacts - Google Patents

Description

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Electrical switching devices are already known in which an insulating body is inserted between the resilient contacts for the purpose of interrupting the current, the main purpose of which is to reduce spark formation when switching off. However, this type of construction is associated with certain disadvantages, since the contacts are coated over time by parts of the insulating compound, which are scraped off by the insulating body when it comes in between. This contamination of the contacts causes undesirable increases in the transmission resistance. In addition, the insulation of the contacts loses its reliability if the insulating body is covered with dust, which is suitable - to form a conductive bridge. It has been proposed to avoid such drawbacks, the insulating ^ao body form so that it first contacts z. B. by acting on approaches of the same, pressed apart and only then occurs with a lamellar part between the actual contacts. In this way, ² S, the aforementioned evils are probably largely avoided; on the other hand, the formation of sparks cannot be completely suppressed, since the insulating lamella only comes between them after the contacts have been pushed apart without touching them. The scale deposits that occur at the points of fire as a result of the formation of sparks are therefore not removed and cause malfunctions over time.

The invention aims to take advantage of the direct contact between the contacts .and the insulating body are not

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limits and to obtain is that the insulating body having transversely passing through the direction of movement wells as ■ / .. as grooves, slots o. the like. is provided. This design of the insulating body avoids the formation of a conductive bridge by deposited dust and, as a result of the lower friction surfaces, also reduces the wear of the insulating body, so that coating the contacts with insulating material is not an option. On the contrary, the special shape of the insulating body makes it much easier to keep the contacts bare. - -

In contrast to electrical switches with a contact bridge, which have insulation the same against the switching movement limiting and the snapping of the bridge in the new switching position causing devices and against the pivot pin of the Switch is necessary, the insulating lamella can with the in a known manner Leaf springs influenced polygon and that interacting with a .Fortsatz of the spindle Driving device consist of one piece, which is a significant simplification depending on the design of the switch. Another embodiment relates to the interaction of the polygon with the Leaf springs, which is known to support the rotary movement or when it is reached the switching positions is limited. According to the invention are at the corners of the polygon Bulges provided, which cooperate with wave-shaped elevations of the leaf springs, so that the snapping of the polygon into the new position suddenly and as a result of overcoming the occurring when crossing the elevations Resistance exerted greater force takes place at greater speed and the friction on the springs increases this way is reduced or completely eliminated.

In the drawing, the subject matter of the invention is illustrated, for example, and although they show

Fig. Ι and 2 a rotary switch schematically in view and plan view. the

Fig. 3 and 4 show two embodiments of the insulating body. In the

Fig. 5 and 6 is the interaction of a square with the leaf springs in the Shown in plan, in one case the switch position, in the other the moment is held after the bead has just exceeded the elevation.

As can be seen from Fig. 1, the insulating lamella inserted between contacts 1 and 2 is 3 Sharpened like a knife or wedge on both the front and the rear edge. The lamella is rotated by the spindle 4.

In a recess of the base 5 are two leaf springs clamped in the same 6, 6 '(Fig. 1,5,6). To the pivot pin 4 is an insulating body in certain Limits rotatable, the lamella in itself 3. the square 7 and one part 8 of the driver device united. The blade is transverse to the direction in which it moves between the contacts with traversing Provided wells, which can also have different shapes. In Fig. 3— is a lamella with in cross section Depicted trough-like grooves. The lamella according to Fig. 4 shows the arrangement of Grooves which produce a wavy surface in cross-section. Au «practical For reasons, the recesses on the top and bottom are offset from one another arranged.

Since the contacts with the surface of the lamellae have fewer contact surfaces and dust deposits are wiped off into the depressions during the circuit, where they are harmless, the formation of a conductive bridge is prevented. The dislodged as a result of wear particles of insulating material may not remain g easily stick ₀ on the contacts because the Oherflächenform the lamella favors a constant polishing the contacts. Incidentally, the wear on the lamella and the contacts is significantly reduced as a result of the lower chances of friction.

According to the invention, with switches, where the interruption of the current through Insertion of an insulating body between the contacts takes place, even for several contact pairs, such as B. with series connection, only a single insulating piece is used, which is three-pronged depending on the number of contact pairs, is cross-shaped or star-shaped. The material used for the insulating body is Hard material, glass, porcelain or the like. Used.

The part 8 consists of an approach that is excluded after a sector, the angle of which ^{slightly exceeds the angle of rotation determined by two successive switching positions (in the present case 90 °} ) (Fig. 5, 6). The pivot pin 4 carries a pin 9 which plays in the recess mentioned. When the bolt 4 is rotated, the pin 9 comes into abutment on the edge of the recess of the part 8, whereby the insulating body, that is to say the square 7 and the lamella 3, is carried along. As soon as the dead center position is exceeded (Fig. 6), the insulating body must be able to move into the new switching position without being affected by the given

if the remaining pin 9 is blocked to | be what the angle of the cutout determined in part 8. The lamella is indicated by dash-dotted lines in the plan. The contacts themselves are not shown. the Springs play a twofold role here. The complete avoidance of sparking is only achieved if the insulating lamella is operated at a certain speed is inserted between the contacts or pulled out of these, which is just next the already mentioned effect is also brought about by these springs.

At the corners of the square beads 10 are provided, which in the switching position (Fig. 5) all rest against the leaf springs 6, 6 '. Each spring is by cropping with a small protrusion 11 protruding in a wave-shaped manner inward. Will If the square is rotated out of the switching position, the beads 10 must meet the elevations 11 exceed what is known to result in a rapid shift. The arrangement of the beads above all brings the advantage that after crossing the elevations by the same Until the new switch position has been reached, there is no contact to inhibit the release takes place between square and leaf springs, since the spring is set back between two beads Side surface of the square not so quickly from the spring returning from the outermost deflection position can be reached. The elevation is in the sense of the direction of rotation of the polygon (clockwise) placed in front of the center of the spring (Fig. 5,6). As a result, the dead gear when the switch is operated namely the movement from the original switch position until it is exceeded the survey can be shortened or avoided entirely. As a result, it becomes the Distance, which the bead passes through after crossing the elevation up to the new switching position, extended, whereby the applied force comes into effect over a somewhat longer period of time and the square or the insulating lamella moves into the new switch position at greater speed.

The beads 10 come with the elevations on the leaf springs when reaching the new switch position in stop when the survey is sufficiently far in front of the middle of the Spring is arranged. This position is shown in Fig. 5. The aforementioned dead gear is omitted here completely, as the bead climbs over the elevation immediately when the switch is pressed. Fig. 6 shows the moment when the bead has just passed the elevation. ·

Claims (1)

Patent Claims: i. Electrical switching device in which to avoid sparking when switching off an insulating body is inserted between the contacts, characterized in that the Insulating body with recesses that are expediently transverse to the direction of movement, such as B. grooves, grooves, incisions o. The like, is provided so that despite direct contact between the insulating body and the contacts results in the formation of a conductive bridge of dust particles avoided, the wear of the contacts is reduced and keeping them blank is guaranteed. • 2. Electrical switching device, in which to avoid sparking an insulating body is inserted between the contacts, characterized in that that the insulating body made of hard material, glass, porcelain or the like also forms a single piece for several pairs of contacts. 3. Electrical switching device according to claim 1, wherein the movement the insulating lamella and the limitation of the rotary movement of the same in the switching go Positions due to the action of leaf springs, a polygon takes place, thereby characterized in that the lamella (3) cooperate with the polygon (7) and with an extension (9) of the spindle Driver device (8) thus the entire switching mechanism consists of one piece. 4. Electrical switch according to claim 3, characterized in that at ioo the corners of the polygon with wave-shaped elevations (11) of the leaf springs (6) coming from the outside in stop beads (10) are provided so that after the elevations are exceeded by the There is no obstructive contact between the polygon and the leaf springs until the new switch position is reached. 5. Electrical switch according to Ann Claim 4, characterized in that the elevation (11) with reference to the sense of rotation of the polygon (7) is arranged in front of the center of the spring (6). 1 sheet of drawings.