EP0110010B1 - Motor circuit breaker - Google Patents

Abstract

A rocking beam is movable into an "on" and an "off" position by actuating means which actuate linkage means and work against the force of a spring urging the beam into an intermediate trip-position. Through a guide surface the beam actuates a toggle assembly composed of two toggle levers linked by a toggle joint and having distal joints linked with a contact actuating lever and a pawl lever, respectively. When the pawl lever is restrained by the ratchet, the movement of the toggle joint caused by moving the actuating means into the "on" or "off" position results only in the opening and closing of contacts through a movement of their actuating lever. A readiness for switching on can be obtained by resetting the actuating means from the trip-position into the "off" position. If the switch is "on" and the pawl is released by the overload current trigger, then the spring can move the beam together with the actuating means into the intermediate, or trip, position, while a spring opens the contacts by operating the actuating lever. If the switch is released through the action of the short circuit trigger, then a toggle is also tripped and an external display becomes visible. It remains so until the toggle is reset by putting the actuating means into the "off" position. The switch can be reset by the same simple action.

Description

The invention relates to a motor protection switch according to the first part of claim 1.

Such a switch is described in US-A-4 090 158. It has the disadvantage that an overcurrent trip is not recognizable at all. H. the switch can only be seen in the on state even when an overcurrent is triggered. There is no alternative but to try out when the engine is at a standstill, which is questionable and tedious when it comes to gear shift controls and / or «remote control. It can be restarted by switching it off and then on again. In the event of a short-circuit tripping, the switches remain externally in the on position except for a special external display. Switching on again requires the actuator to switch off beforehand. However, it can only be switched on again after the external display has been returned. This can be problematic for short-circuit tripping, which is usually rather rare, and not only for untrained people.

Motor protection switches according to US Pat. Nos. 3,935,409 and 4,163,881 are also known, in which each triggering of whatever cause (ie overcurrent and short-circuit triggering) leads to an externally recognizable trip position of the actuating member. This is dangerous because if the cause of the tripping is not known, it can be switched on again even in the event of a short circuit, without prior elimination of the short circuit. This can have serious consequences.

The invention has for its object to provide an economically producible, reliable motor protection switch, in which it is perfectly recognizable from the outside, in which operating state it is and whether an overcurrent or a short circuit has occurred. A restart operation in both triggering cases should be able to be carried out safely in the same simple manner.

To solve this problem, a motor protection switch according to claim 1 is proposed.

It can be seen from the outside of the actuating member of the motor protection switch according to the invention whether it is in the off, on or trip position. When the actuator is in the trip position without any further external display, it is clear that it is an overcurrent release. After the bimetallic element has cooled down, the readiness to be switched on again can be achieved by moving the actuating member from the trip position to the off position. Then you can switch on again.

However, if a short-circuit release is the cause of the trip position of the actuator, the outer display is also visible. We now know that a short circuit remedy should precede the restart. One can bring about readiness for reclosure by simply moving the actuator from the trip position to the off position. The outer display is also returned to the idle position. It can be switched on again.

So you can easily create safe display conditions according to the invention, the effort is very modest.

Preferably, a rocker bar that is operatively connected to the linkage is provided, which is connected to a spring, which strives to hold the rocker in its middle trip position. The spring is tensioned when you switch on or off, whereby the rocker is swiveled towards one side or the other like a balance beam.

If the on position is present and tripping occurs, the spring can return the rocker to the trip position, and the actuator can also be moved to the trip position. You can also let other parts of the boom move from the seesaw to a trip position.

The rocker can be used in this way to bring about the trip position of the actuating member.

To “latch” the switch that has not been triggered, knee joint brackets are preferably used, the two brackets of which are connected by a knee joint in such a way that a kinked position of the knee joint brackets is latched on both sides of a stretched position. The one kink position is the off position and the other kink position is the on position. The on and off position can be reached by moving the knee joint accordingly.

The free end of the one link is preferably connected by an end joint to a contact actuating lever which can be pivoted about a frame bearing, while the free end of the other link is connected by an end joint to a latch lever which can be pivoted about a frame bearing. Both of the mentioned end joints are arranged in such a way that a straight line connecting them lies in every position of the linkage between the on and the off position of the knee joint. As a result, after the off position has been brought about, it can only be switched on again if the pawl is again latched onto the pawl lever in the course of a switch-off movement.

The knee joint is preferably guided in a guide running transversely to its switching movement direction and is drive-connected to a linkage part articulated on the rocker.

The knee joint can take account of the various switching states from its on position along the guide, while evading laterally. So the knee joint can release and release the ratchet lever including the linkage and rocker are moved from the rocker spring to the trip position, while the contact operating lever swings into its off position and can separate the contacts.

No matter what the cause of the trigger is. It can only be switched on again after the actuating element together with the rocker and thus with the linkage part has been brought into the off position, the linkage part bringing the knee joint into its off position. Since the contact actuation lever is already in its off position, where it can be held resiliently, the movement of the knee joint from the trip position to the off position causes the latch lever to move into its latched position, in which the latch can snap back into place. Of course, a cooling break after overcurrent tripping or short circuit elimination is essential.

However, if the trigger is triggered by a short-circuit release, the outer display is also visible, which does not fundamentally change the restart process, but clearly warns of it.

This outer display is advantageously operatively connected to a bistable tilting device, only the short-circuit release being able to transfer the tilting device from its rest position into the display position. This means that the outer display remains in the rest position until a short-circuit is triggered, but that it now remains in the display position after the tilting device has been tilted until the tilting device is returned to the rest position. This return is preferably carried out when the actuator is moved from the trip to the off position. This means that readiness for switch-on is created, as previously described. The actuating member or a linkage part can be designed such that an active connection can only take place during the aforementioned return process of the tilting device in the display position. This is easily possible. A preferred solution can be seen in the drawing.

• Figur 1 einen erfindungsgemässen bevorzugten Motorschutzschalter in der Aus-Stellung,
• Figur 2 diesen Motorschutzschalter in der Ein-Stellung,
• Figur 3 diesen Motorschutzschalter in seiner durch den Ueberstromauslöser ausgelösten Trip-Stellung, und
• Figur 4 diesen Motorschutzschalter in seiner durch den Kurzschlussauslöser ausgelösten Trip-Stellung.

The invention is discussed below with reference to the purely schematic drawing, for example. The diagrams show:

• 1 shows a preferred motor protection switch according to the invention in the off position,
• FIG. 2 this motor protection switch in the on position,
• Figure 3 this motor protection switch in its trip position triggered by the overcurrent release, and
• Figure 4 this motor protection switch in its trip position triggered by the short-circuit release.

The frame of the motor protection switch is represented by triangles hatched on one side as support points and by parallel lines hatched on both sides as sliding guides of the frame. - Circles indicate joints.

The motor protection switch shown has a fixed contact pair 1 which can be connected to supply lines and a contact pair 2 which is movable relative thereto.

For normal operation, i.e. H. for switching on and off, a pair of switching buttons with an on button 3 and an off button 4 is provided as an externally visible actuating member, which act on a linkage 5.

The rocker 10 which can be operated by means of the control buttons is mounted on the frame at point 100 and is urged into its central position (corresponding to its trip position in FIGS. 3 and 4) by its rocker spring 11. This rocker 10 is in operative connection with the knee joint 15 of the knee joint brackets 12 via the plunger 23 and the sliding guide 22 attached to it.

The tab 13 of the knee joint tabs 12 is connected to the angular contact actuation lever 18 via the end joint 16. The contact actuating lever 18 is pivotally mounted on the frame bearing 17 and is pulled by the spring 180 against the stop 181 into the disconnected position of the contacts (FIGS. 1, 3 and 4).

The tab 14 of the knee joint tab 12 is connected to the pawl lever 21 via the joint 19. This pawl lever 21 is pivotally mounted on the frame about the bearing 20 and is held in the latched position (FIGS. 1 and 2) by the pawl 6 against the spring 210 on or close to the stop 211.

A bimetallic element is indicated as the overcurrent release 7, which can actuate the pawl 6 via a plunger 70 without the release linkage 81 of the short-circuit release 8 being moved thereby.

The short-circuit release 8 is an electromagnetic device indicated by the relay symbol, the armature of which actuates the linkage 80, 81 when a short-circuit current flows. The trigger linkage 81 can trigger the pawl 6 without moving the plunger 70 of the overcurrent release 7. The display linkage 80 of the short-circuit release 8 is shown here as a plunger which lies loosely (only for pushing, not for pulling) on the outer display 9.

The outer display 9 is operatively connected to the rocker arm 240 of the bistable tilting device 24, which is held by the rocker spring 241 in the rest position (FIGS. 1 to 3) or display position (FIG. 4). The rocker arm 240 can be returned by the return member 30 of the linkage 5 from the display position (FIG. 4) to the rest position (FIG. 1) when the trip position is switched to the off position.

The motor protection switch can be switched on by pressing the on button 3 from the off position (FIG. 1) to the on position (FIG. 2), its linkage 5 from the off position shown in FIG. 1 to the position shown in FIG 2 On position shown passes over. In this case, the rocker 10 is tilted clockwise and the knee joint lashers 12 are moved from their out-of-bend position to the in-bend position in the extended position, not shown, in which they remain. Here, only the contact operating lever 18 is velvet Contact pair 2 moves because the knee joint plates 12 are articulated with the knee joint 15 in the sliding guide 22 and with the end joint 19 on the pawl lever 21 held immovably (between the stop 211 and the pawl 6).

Conversely, the switch-off takes place by pressing the switch-off button 4, starting from the on position in FIG. 2 to get into the off position in FIG. 1.

If the motor protection switch is now in the on position in FIG. 2, it can reach one of the two trip positions shown in FIGS. 3 and 4 by triggering.

Overcurrent release (FIG. 3): An overcurrent heats the overcurrent release 7, which releases the pawl 6 against the spring 60 via its plunger 70. After the overcurrent release 7 has cooled (its circuit is interrupted when it is released), the pawl 6 returns to the rest position pulled by the spring 60. The trip position of the switch buttons (without the outer display 9) indicates overcurrent tripping. As a result, the detached pawl lever 21 can move from the spring 210 from the latching position shown in FIG. 2 to the release position shown in FIG. 3. As a result, the end joint 19 is moved to the right and the spring 11 can pull the rocker 10 into the trip position via the tappet 23. The knee joint brackets 12 are no longer supported by the end joint 19. The spring 180 can pull the contact actuation lever 18 together with the contact pair 2 into the off position. The contact operating lever 18 is now missing the support on the end joint 16.

Resetting in readiness for switching on: By pressing the off button, the entire position of the entire linkage can be restored, with the ratchet lever 21 being pulled back into the latching position by the knee joint tabs 12 via the end joint 19. The contact actuation lever 18 lies against the stop 181, so that the end joint 16 cannot be pulled to the right. So lifting the knee joint 15 by the sliding guide 22 causes a pull on the tab 14, which the latter transmits via the end joint 19 to the latch lever 21. The motor protection switch is ready to be switched on.

Short-circuit release (FIG. 4): If a short-circuit occurs, the short-circuit release 8 is activated, which causes a movement of the release linkage 81 and the release of the pawl 6. The process described above follows. However, the responsive short-circuit release 8 has also actuated the display linkage 80, which has pushed out the outer display 9 and thereby tilted the tilting device 24 over its dead center position. Although immediately after the triggering of the short-circuit release 8 (its circuit is interrupted when triggered) returns to the rest position, the display position of the outer display 9 and the tilting device 24 remains.

The trip position of the actuator (both buttons 3 and 4 are at the same height) and the outer display indicate that the short circuit has been triggered. You can immediately see that it is not allowed to switch on again without removing the short circuit.

However, if the short circuit has been remedied, we can proceed as described above under "Resetting in standby mode". In this case, the return member 30, actuating the rocker arm 240, will return the rocker device 24 and the outer display 9 to the rest position.

The switch-on standby position corresponds to the off position in FIG. 1.

Thus, it was shown how simple, yet functionally reliable one he ^f indungsgemässer motor circuit breakers can be built, of course, can not be built only a single phase but also a multi-phase motor circuit breakers similar. One trigger per phase can then take the place of one.

Claims (6)

1. Motor circuit breaker with a frame and at least one contact piece (2) which is movable relatively to at least one resting contact piece (1), the movable contact piece being movable against the urge of a spring into an « on position and back into an « off position by way of a manually operated actuating means (3, 4) and through linkage means (5) which are locked by a pawl (6) in the « on position in such a way that when the pawl (6) is released, either by an overload-current trigger (7) or by a short circuit trigger (8), the linkage means will take up a trip-position, and with external display means (9) which give an external indication whenever a short circuit has occurred, characterized in that said actuating means (3, 4) can take up a position which corresponds to a trip-position (Figs. 3, 4) of said linkage means (5) and is ascertainable from outside, in that this trip-position without said external display means (9) indicates a triggering through current overload, whilst said position together with said external display means (9) indicates a triggering due to a short circuit, .in that after a triggering said actuating means (3, 4), said linkage means (5), and if applicable said external display means (9), can be put into readiness for a switch-on by moving said actuating means (3, 4) into the « off position (Fig. 1), and that the « on » position (Fig. 2) can thereafter be reset by operating said actuating means (3, 4).

2. Motor circuit breaker according to claim 1, characterized by a rocking beam (10) urged by a spring (11) into its middle position which corresponds to the trip-position (Figs. 3, 4) in that said actuating means (3, 4) are arranged to rock said beam (10) seesaw-like to any side of said middle position against the force of said spring (11), either into the « on " position (Fig. 2) or into the « off position, and that said beam (10) is functionally connected with the actuating means (3, 4) and said linkage means (5).

3. Motor circuit breaker according to any preceding claim, characterized in that said linkage means (5) comprise a toggle assembly (12) with two toggle levers (13, 14) linked by a toggle joint (15), each having an outer joint (16, 19), whereby said toggle joint (15) can only be brought from an « off position (Fig. 1) where said toggle assembly is angled in one direction, through a stretched position into a locked a off position (Fig. 2) where it is angled in the opposite direction, when said linkage means (5) is in a ready state (Fig. 1).

4. Motor circuit breaker according to claim 3, characterized in that one outer joint (16) is linked to a contact-actuating lever (18) hinged on a rocker bearing (17) attached to the frame, and that the other outer joint (19) is linked to a pawl lever (21) hinged on a rocker bearing (20), the arrangement being such that a straight line drawn from one outer joint to the other always lies between the « off position (Fig. 1) and the « on position (Fig. 2) of said toggle joint (15).

5. Motor circuit breaker according to claim 4, characterized in that said toggle joint (15) is guided laterally to its switch motion by a guide fence (22) connected to a rod system (23) which is itself linked to the beam (10).

6. Motor circuit breaker according to one of the preceding claims, characterized in that said external display means (9) is linked to a bistable toggle device (24) which can only be tilted from its resting position (Figs. 1 to 3) to its display position (Fig. 4) by the action of the short circuit tripping device (8), and where said toggle device can be reset from its display position (Fig. 4) by moving said actuating means (3, 4) from the trip-position (Fig. 4) into the « off position (Fig. 1).

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