DE20121223U1 - Drive system for the movable contact of a an electrical power switch with contact bounce prevention - Google Patents

Abstract

The electrical power switch has a movable contact [4] that is moved relative to a fixed contact [3] by an actuator system [15] coupled by a linkage system [[6-8]. The linkage system includes a facility to prevent contact bounce. A pivot mounted link [7] has a pin [30] that moves to engage a claw ended link [29] at first opening and so retains the contact.

Description

2001 G 18382 EN

Description

Drive train for a movable contact of an electrical switch
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The invention is in the field of electrical switches and is to be used in the structural design of a drive train for a movable contact of an electrical switch, which has a drive element associated with the movable contact, which can be moved against a stop when the movable contact is opened and which is associated with an impact protection device. The invention relates to electrical switches which have an indicator for the switch's readiness to be switched on, which can be moved from a first position "ready to switch on" to a second position "not ready to switch on".

In a known electrical switch of this type, the impact protection device is associated with a switching shaft and has a catch element and a counterpart arranged on the drive element (switching shaft) which is associated with the catch element, the catch element being arranged on a first arm of a two-armed lever which is under the action of a spring in such a way that it pivots into the path of movement of the counterpart by actuation of the second lever arm.

The counterpart is designed as an arc-shaped contour on a lever that protrudes radially from a switching shaft. The catch element is formed by an angled end of the first lever arm. (Product: Low-voltage circuit breaker 3WN6 from Siemens AG, Germany).

The two-armed lever, which is fixed in place in the switchgear in this drive train, is actuated by a

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The working surface of the counterpart is impacted and swings into the path of movement of the counterpart to varying degrees depending on the strength of the impact. In order to prevent the catch element from bouncing on the counterpart at both a very high and a very low speed of the opening movement of the switching shaft and thus to ensure that the switching shaft bounces back in the direction of the closed position of the contacts by catching the counterpart using the catch element, two bounce protection devices with two-armed levers with different spring loads are provided.

Starting from a drive train with the features of the preamble of patent claim 1 (product:

The invention is based on the object of designing the impact protection device in such a way that the rebound forces acting on the drive element, which result from the possible opening speeds of the movable contact coupled to the drive element, can also be controlled by a single impact protection device.

This object is achieved according to the invention in that the second lever arm is coupled to the indicator for the readiness to switch on with play in such a way that when the indicator is in the "not ready to switch on" position, the catch element projects into the path of movement of the counterpart and the counterpart slides over the catch element like a snap lock when the 0 movable contact is opened. - With such a design, the catch element projects independently of the speed of the drive element and thus independently of its impact force.

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into the movement path of the counterpart before the opening process. Only a small deflection of the catch element is therefore required for the catch element to slide over the counterpart like a snap lock. Only a fraction of the kinetic energy of the switching shaft is transferred to the catch element via the counterpart, so that even very different speeds of the switching shaft during the opening process lead to essentially the same movement sequences of the catch element.

The counterpart can advantageously be designed as a bolt fixedly arranged on the drive element and the catch element as a catch hook formed on the free end of the first lever arm and provided with a sliding surface for the bolt, wherein a coupling rod is used to couple the second lever arm to the indicator element, which is penetrated in the region of an elongated hole by a pin arranged on the second lever arm.

0 An embodiment of the new drive train is shown in Figures 1 to 3. Figure 1 shows a schematically illustrated low-voltage circuit breaker with a drive train in which a drive element is designed as a switching shaft for the joint drive of several movable contacts arranged parallel to one another and is secured against rebounding during the opening process by means of a bounce protection device and with an indicator for the switch's readiness to switch on,

0 Figure 2 shows the drive train with the indicator in a "ready to switch on" position, where the switching shaft is released by the impact protection device to close the contacts and

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Figure 3 shows the drive train with the indicator in the "Not ready to switch on" position, where the switching shaft is moved against the stop and is secured against rebounding by the bounce protection device during the opening process of the contacts.

The low-voltage circuit breaker according to Figure 1 has a switching pole assembly 1 in which a contact system is arranged in a housing 2. The contact system is part of a switching pole of this switch and has a fixed contact 3 and a movable contact 4. Also arranged in the housing are a pivoting contact carrier 5 carrying the movable contact and a coupling lever 6 for coupling the contact carrier 5 to a switching shaft 7. The switching shaft serves as a drive element for several switching poles arranged parallel to one another, only one of which is visible in Figure 1. The switching shaft 7 is connected to the coupling lever 6 of a respective contact carrier 5 by a lever 8 protruding radially from its axis. An arc quenching chamber 3 9 can be inserted into the housing 2 in a known manner. The movable contact 4 consists of several contact levers 9 arranged parallel to one another, which are pivotably held in the contact carrier 5 by means of a hinge pin 10 and are pre-tensioned by two contact force springs 11 each. Flexible conductors 12 serve to connect the contact levers 9 to a lower connection rail 13. The fixed contact 3 assigned to the movable contact 4 is connected to an upper connection rail 14.

A support structure 15 of a drive device is attached to the housing 2 of the switching pole assembly 1. The drive device and other switch parts are connected to the housing 2 by means of a

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The switching shaft is protected by a cover 40 attached to it. The switching shaft is coupled in its middle area to a storage spring 16 of the drive device. For this purpose, a lever 17a forming one end of a coupling strand 17 is coupled to the lever 8 of the switching shaft 7 by means of a first coupling bolt 18. A tensioning lever 17b forming the other end of the coupling strand 17 rests on a pressure piece 19 of the storage spring 16. The storage spring can be tensioned in a known manner (not shown in more detail) by means of a motor and/or manual drive and can be latched in the tensioned state by means of a switch lock (also not shown). A device for controlling the switching on of the switch is also held on the supporting structure 15, of which only an indicator element 20 for the switch's readiness to switch on is shown in the figures. The functioning of such a device for controlling the switching on of a switch, its exposure to operational parameters, and its interaction with a switch lock are known, for example, from the patent specification DE 199 57 391 Cl 0.

According to Figure 2, the indicator element 20 is pre-tensioned in a first position "ready for switching on" under the force of a return spring 22 acting on a first arm 21, in which a first section 23 of a display surface of the indicator element 20, visible to the observer in the direction of arrow A, indicates that the switch is ready for switching on. The indicator element can be rotated counterclockwise by means of various drivers into a second position (represented by the dash-dot line in Figure 2) in a manner also known from patent specification DE 199 57 3 91 Cl, in which a second section 24 of the

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display area becomes visible, indicating that the switch is not ready to be switched on (see also Figures 1 and 3).

The indicator element 20 has a second arm 25 which is coupled to a two-armed lever 27 by means of a coupling rod 26. This two-armed lever 27 is part of an anti-bounce device which serves to reliably prevent the switching shaft 7 from bouncing back into a position corresponding to the closed position of the contacts 3, 4 after it has struck a stop 28. The two-armed lever 27, which is held in a stationary manner on the supporting structure of the drive device, has a molded-on catch hook 29 on one lever arm which is assigned to a bolt 30. This bolt 30 is arranged on a further lever 31 which projects radially from the axis of the switching shaft. In order to couple the indicator element 20 to the second lever arm of the two-armed lever 27, one end of the coupling rod 26 is coupled via a second coupling bolt 33 which passes through the second arm 25. The other end of the coupling rod 26 has an elongated hole 34 into which a pin 35 engages. This pin 35 is arranged on the second lever arm of the two-armed lever 27. A tension spring 36 also engages on the second lever arm, which pre-tensions the two-armed lever 27, which can be pivoted about a pivot bearing 37, clockwise in a stop position on the coupling rod 26. In this position of the indicator element 20 and the two-armed lever 27, the bolt 30 arranged on the further lever 31 is released from the catch hook 29, so that the switching shaft 7 can be rotated clockwise to close the contacts. In a known manner, when the contacts are closed, the indicator element 20 is transferred to its second position "not ready to switch on". The two-armed lever 27 coupled to the indicator element 20 is thereby

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the force direction of the tension spring 3 6 clockwise into a

Catch position (see Figure 2).

According to Figure 3, the further lever 31 is in a first position when the contacts are closed. The catch hook 29 already projects into the movement path of the bolt 30 shown by the circular arc B when the switching contacts are closed (catch position of the catch hook). The catch hook 29 has a sliding surface 38 facing the bolt 30. During the switching off process, the switching shaft 7 pivots anti-clockwise. The bolt 30 hits the sliding surface 38 and slides - pivoting the two-armed lever 27 anti-clockwise out of its stop position on the coupling rod 26 and thus out of its catch position - on the angled free end of the catch hook (cf. position of the further lever 31 and the two-armed lever 27 shown by dash-dot lines). When the bolt 30 slides off, the two-armed lever 27 is swung back clockwise under the force of the tension spring 36 into its stop position on the coupling rod 26 and thus into its catch position. A rebound of the switching shaft 7 after the further lever 31 of the switching shaft 7 has struck the stop 28 is thus reliably prevented.

If the bolt 30 is provided on one of the levers 8, the additional lever 31 of the selector shaft 7 can be dispensed with.

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List of reference symbols

I Switching pole assembly

2 Housing of the switching pole assembly

3 Fixed contact

4 Movable contact

5 Pivoting contact carrier

6 Coupling lever 7 Shift shaft

8 levers

9 Contact lever

10 hinge pins

II Contact force spring 12 Flexible conductors

13 Lower connection rail

14 Upper connection rail

15 Supporting structure of the drive device

16 Storage spring 17 Coupling strand

17a Coupling lever

17b clamping lever

18 coupling bolts

19 Pressure piece

5 2 0 Indicator of a device for controlling the switching on of the switch

21 First arm of the indicator

22 Return spring

23 First section of the display area 24 Second section of the display area

25 Second support of the indicator

26 coupling rods

2 7 Two-arm lever

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2 8 Stop

2 9 Moulded catch hook

3 0 bolts

31 Additional lever of the selector shaft

33 Second coupling bolt

34 Long hole

35 pen

3 6 Tension spring

3 7 Swivel bearing

38 Sliding surface

3 9 Arc extinguishing chamber

4 0 Cover

A Arrow direction corresponding to the line of sight through a

Viewing window corresponds

B Movement path of the counterpart (bolt 30)

Claims (2)

1. Drive train for a movable contact ( 4 ) of an electrical switch, which has an indicator ( 20 ) for the switch-on readiness of the switch, which can be moved from a first position "ready to switch on" to a second position "not ready to switch on", with a drive element ( 7 ) associated with the movable contact ( 4 ), movable against a stop ( 28 ) when the movable contact is opened, to which a bounce protection device is associated, - in which the impact protection device has a catch element ( 29 ) and a counterpart ( 30 ) arranged on the drive element, - wherein the catch element ( 29 ) is arranged on a first arm of a two-armed lever ( 27) under the action of a spring (36 ) in such a way that it pivots into the movement path (B) of the counterpart ( 30 ) by actuation of the second lever arm, characterized in that that the second lever arm is coupled to the indicator element ( 20 ) for the readiness to switch on with play for its actuation in such a way that when the indicator element is in the "not ready to switch on" position, the catch element ( 29 ) projects into the path of movement (B) of the counterpart ( 30 ) and the counterpart slides over the catch element like a snap lock when the movable contact ( 4 ) is opened. 2. Drive train according to claim 1, characterized in that - the counterpart ( 30 ) is designed as a bolt fixedly arranged on the drive element and the catch element ( 29 ) is designed as a catch hook formed on the free end of the first lever arm, - wherein the catch hook ( 29 ) is provided with a sliding surface ( 38 ) for the bolt ( 30 ) and - wherein a coupling rod ( 26 ) is used to couple the second lever arm to the display element ( 20 ), which is penetrated in the region of an elongated hole ( 34 ) by a pin ( 35 ) arranged on the second lever arm.