EP1918952A2 - Ground fault circuit interrupter - Google Patents

Abstract

The interrupter (32) has a switching shaft (10) that is rotatable from off into on positions by a handle and a switch lock. A fixed contact contacting with its movable contact is connected with the shaft in the on position such that a loop is closed. The shaft is unaccommodated in the on position during duration of a blockade by the lock by an exertion of torque on the shaft by a spring. The shaft is pushed from the on position in the direction of the off position by the lock after completing the blockade. Another spring (30) pushes back the shaft completely in the off position.

Description

The invention relates to a residual current circuit breaker, with a by means of a handle and a subordinate switching mechanism from an OFF position to an ON position rotatable switching shaft, wherein in the ON position connected to the switching shaft and movable contact with it touches a fixed contact and such a circuit closes, and wherein in the ON position on the switching shaft by a first spring, a constant torque is exerted, which, however, the shift shaft in the ON position during the period of a blockade by the switch lock does not yield, and after quitting the blocking by the switch lock (when the handle is actuated or a relay acting on the switch lock) forces the switch shaft from the ON position towards the OFF position.

The first spring may be a tension or a compression spring. The bias of the first spring is such that the torque it exerts becomes ever smaller as the shift shaft moves from an ON position to the OFF position. This occasionally causes the problem that the OFF position is not fully achieved. In addition, occur when turning back the shift shaft, in which the movable contact of the fixed contact away, arcs between the two contacts, which must be interrupted by the force of the spring, to which the force of the spring is often insufficient.

From the U.S. Patent 3,735,073 For example, a switch is known in which an additional spring-closing element is provided for assisting a transfer to the ON position.

It is an object of the invention to develop a residual current circuit breaker of the type mentioned in such a way that the OFF-position is achieved unerring and thereby effective arcs are interrupted.

The object is achieved in that the residual current circuit breaker of the type mentioned includes a second spring, which completely pushes back the shift shaft in the OFF position. Due to the fact that the second spring urges the selector shaft completely into the OFF position, the first spring can retain the weakness of not fully shifting the selector shaft into the OFF position by its own power. Since the second spring supports the first spring, arcs are also effectively interrupted.

A disadvantage of the first spring of the prior art is also that the switching mechanism is loaded by the torque constantly exerted by it. If you want to avoid excessive stress on the switching mechanism, so you can make the arrangement of the second spring in an advantageous manner so that this acts differently than the first spring and in particular does not always exerts a torque on the shift shaft. In particular, the arrangement may be such that the second spring engages a body rotatable with the shift shaft so as to exert no torque on the shift shaft in the ON position or exert a counteracting torque to the torque exerted by the first spring (this opposite Torque, however, may not reach the amount of torque exerted by the first spring for the remaining torque to cause it to leave the ON position).

The engagement of the second spring on the rotatable body may be further such that the second spring, after initiating rotation of the control shaft with the body and exceeding a critical angle, which may be greater than zero, exerts torque which increases with rotation of the control shaft , This increasing torque compensates for the torque exerted by the first spring becoming smaller and the target to fully disengage the shift shaft to spend in the OFF position, is achieved particularly effectively.

The second spring is supported for example on a fixedly mounted in a housing of the residual current circuit breaker holder and presses a relative to the holder movable plunger against an abutment in the rotatable with the switching shaft body. With appropriate placement of the anvil, the goal can be effected that in the ON position substantially no torque is exerted on the shift shaft. If the body rotates, the lever arm increases in almost constant, exerted by the second spring force, so that the torque increases to the rotatable with the switching shaft body and thus on the shift shaft itself.

FIG 1

die zum Verständnis der Nachteile eines Fehlerstromschutzschalters des Standes der Technik zu erläuternden Bauteile eines solchen Fehlerstromschutzschalters im Schnitt zeigt,

FIG 2

eine teilweise durchbrochene Seitenansicht eines erfindungsgemäßen Fehlerstromschutzschalters in seiner EIN-Stellung veranschaulicht und

FIG 3

den Fehlerstromschutzschalter aus FIG 2 in seiner AUS-Stellung veranschaulicht,

FIG 4

das von den zwei Federn des erfindungsgemäßen Fehlerstromschutzschalters auf die Schaltwelle ausgeübte Drehmoment einzeln und in Summe veranschaulicht.

Hereinafter, a preferred embodiment of the invention will be described with reference to the drawing, wherein

FIG. 1

FIG. 2 shows, in section, the components of such a residual current circuit breaker to be explained in order to understand the disadvantages of a residual current circuit breaker of the prior art;

FIG. 2

a partially broken side view of a residual current circuit breaker according to the invention in its ON position illustrated and

FIG. 3

2 illustrates the residual current circuit breaker of FIG. 2 in its OFF position,

FIG. 4

the torque exerted by the two springs of the residual current circuit breaker according to the invention on the shift shaft illustrated individually and in total.

In a residual current circuit breaker, an electrical circuit is closed via a dashed line in FIG. For this purpose, a body 12 is connected to the switching shaft 10, on which a lever 14 is formed, which consists of electrically conductive material. At the end of the lever 14, a contact 16 is formed. Counterpart to the contact 16 is a fixed contact 18, opposite the housing 20 (shown symbolically in FIG 1) is not movable. The contact 18 is connected on the housing side, and the contact 16 is connected via the lever 14 and a copper wire 22 to a terminal 24, which thus constitutes another terminal. 1 illustrates an open position corresponding to the OFF position of the residual current circuit breaker. To get into the ON position, the shift shaft 10 must be rotated counterclockwise, then the lever 14 moves at the end with the contact 16 upwards, and the contact 16 is pressed against the contact 18, so that the circuit is closed. To return to the OFF position, the shift shaft must then of course be reversed rotated, namely clockwise. While switching to the ON position by an operator on a (not shown in FIG 1) handle acting on a (not shown) switching lock on the shift shaft 10, the shutdown can also be done via the handle, but also automatically be triggered by a relay acting on the switch latch. There is then no force applied by an operator available to rotate the shift shaft 10. To provide a torque serving for this purpose, a spring 26 is provided. This is supported with one side on the housing 20 and engages with its other side to another, formed on the body 12 lever 28 at. The spring 26 is designed here as a tension spring, but an embodiment as a compression spring is analogous possible. The spring 26 is intended to apply the force that is necessary to bring the shift shaft 10 in the OFF position. The contact 16 must be removed from the contact 18. Any resulting arcing must be interrupted. The force to be applied by the spring 26 is therefore very high. It is particularly disadvantageous that the force and thus the torque exerted on the switching shaft 10 via the lever 28 decreases the further the shift shaft 10 has turned clockwise because the spring 26 then increasingly relaxes. Especially at the end of the movement is thus very little torque available, so that under certain circumstances, the OFF position is not completely reached. dampening Inter alia, the copper strands 22 act. A stronger orientation of the spring 26 can overcome the disadvantages only conditionally.

The invention overcomes this disadvantage by providing an additional, second spring, the compression spring 30 shown in Figures 2 and 3. Shown in Figures 2 and 3 is a residual current circuit breaker as a whole, which is designated 32. In the picture above, a just mentioned handle 34 can be seen, on which it can be seen that FIG. 2 illustrates the ON position of the residual current circuit breaker and FIG. 3 shows the OFF position. By means of the handle 34, the switching shaft 10 is rotated from FIG 1 via a switching mechanism not to be seen here. In the lower part, which is not completely visible in FIGS. 2 and 3, the components 10 to 28 from FIG. 1 are arranged. The lever 14, the contact 16, the contact 18 and the copper wire 22 can be seen, for example, in FIG. 3. The body 12 is concealed with the lever 28 and the spring 26. In addition to the body 12, it is also located on the selector shaft another body 36, which has the shape of a rounded top rectangular plate. About this body 36, the compression spring 30 engages the shift shaft 10 as follows: The compression spring 30 is supported in Figures 2 and 3 each at the top of a holder 38 from. The holder 38 consists of a plurality of struts, which are fixedly connected to the housing 20 of the residual current circuit breaker 32. The holder 38 has a recess 40 through which a plunger 42 is guided. The compression spring 30 surrounds the plunger 42 over a large part of its longitudinal extent and presses on a collar 44 which is fixedly connected to the plunger 42. On the collar 44, in turn, a bearing 46 is formed, which is mounted in an abutment 48 of the plate-shaped body 36. In the ON position of the residual current circuit breaker 32 according to FIG 2, the bearing 46 presses into the anvil 48 at an angle such that the force of the compression spring 30 almost straightly a rotational axis 50 of the switching shaft 10 pierces. In this case, the total acting on the body 36 and thus the switching shaft 10 torque would be equal to 0. Present extends the straight line extension 52 of the axis of the compression spring 30 and thus the direction of the force exerted by the compression spring 30, in Figure 2 just left on the axis of rotation 50 over, which means that on the plate-shaped body 36, and thus on the shift shaft 10, a slight torque is exerted in the counterclockwise direction. This torque thus acts slightly against the spring 26, which is shown only in FIG 1, in the embodiment of FIG 2 and FIG 3, however, is also present, so that the shift shaft 10 is not moved in the result. Moves after triggering of the switching mechanism by the (not shown) relay of the residual current circuit breaker 32 (or even when switching using the handle 34) of the contact 16 away from the contact 18, and the shift shaft 10 rotates clockwise, the body 36 rotates , and the anvil 48 moves with the bearing 46 stored therein to the right. 2, which indicates the direction of the force action, then passes through the axis of rotation 50 to the right, and it is now a torque formed on the plate-shaped body 36, which is to that of the spring 26th on the lever 28 on the shift shaft 10 exerted torque occurs. 3 shows that the lever arm with the length 1 has been continuously extended, which also increases the torque, which is known to be the product of the force F and the lever arm 1. While the torque exerted by the spring 26 alone tends to decrease as the shift shaft 10 rotates clockwise, the torque exerted by the compression spring 30 even increases. This ensures that the switching shaft 10 reaches in any case the OFF position shown in FIG 3 and the angle α (see FIG 3) overcomes.

The just verbal torque curves described are shown in FIG 4. Each curve represents a torque, in relation to the here indicated in arbitrary units rotation angle of the switching shaft 10 (and also of the body 36). The position "0" corresponds to the OFF position, and the position "28" to the ON position. The curve 54 represents that of the Tension spring 26 alone on the lever 28 on the shift shaft 10 exerted torque again. As the tension spring gradually relaxes when transitioning from the ON position to the OFF position, torque decreases continuously as viewed from right to left. As the curve 56, which reproduces the torque exerted by the compression spring 30, shows, the compression spring 30, as was also explained above with reference to FIG 2, in the ON position, first a torque of the tension spring 26 counteracting torque, However, the amount is much smaller than the same. As described above, the straight 52 passes through the rotation axis 50 upon rotation of the plate-shaped body 36. This is precisely the point at which the torque on the shift shaft exerted by the compression spring 30 is 0, as shown in FIG the position marked "25". Subsequently, the lever arm 1 increases more and more until the situation is reached according to FIG 3. Thus, in the curve 56, this torque increases as one goes through the curve 56 from right to left, that is, when the turn-off operation of the residual current circuit breaker 32 is observed.

By the compression spring 30, as can be easily seen on the total torque curve 58, the drop in torque 54 in the direction of the OFF position is virtually compensated. The provision of the compression spring 30 as a second spring thus has the consequence that the total torque is significantly higher than the torque applied by the tension spring 26 alone, and in particular in the vicinity of the OFF position (in the curves 54, 56 and 58 in each case to the left) the total torque still remains sufficiently large, and in particular not as the torque exerted by the tension spring 26 alone drops sharply.

The compression spring 30 thus not only provides an additional torque, which would be advantageous in itself, but by the advantageous design of the plate-shaped body 36 with the counter-bearing 48 for the bearing 46 is a Given torque curve according to the curve 56, which acts in particular supportive when arcs between the contacts 16 and 18 must be interrupted, and also ensures that the OFF position is achieved accurately.

Claims (4)

Residual current circuit breaker (32) having a by means of a handle (34) and a subordinate switch lock from an OFF position to an ON position rotatable switching shaft (10), wherein in the ON position with the switching shaft (10) and connected with their movable contact (16) touches a fixed contact (18) and thus closes a circuit, and wherein in the ON position on the switching shaft (10) by a first spring (26) a continuous torque is applied to which the switching shaft (10 However, in the ON position during the period of a blockade by the switching mechanism does not yield, and after the blocking of the block by the switching mechanism, the switching shaft (10) from the ON position in the direction of the OFF position urges characterized by
a second spring (30) that fully retracts the shift shaft to the OFF position. Residual current circuit breaker (32) according to claim 1,
characterized in that
the second spring (30) engages a body (36) rotatable with the control shaft (10) so as not to apply torque to the control shaft in the ON position or to exert a torque counteracting the torque exerted by the first spring. Residual current circuit breaker (32) according to claim 2,
characterized in that
the second spring (30), after initiating a rotation of the control shaft (10) with the body (36) and exceeding a critical angle, exerts a torque which increases with the rotation of the control shaft on the control shaft (10). Residual current circuit breaker (32) according to claim 2 or 3,
characterized in that
the second spring is a compression spring (30) fixed to one in a housing (20) of the residual current circuit breaker (32) mounted holder (38) is supported and a relative to the holder (38) movable plunger (42) against an abutment (48) in the connected to the switching shaft (10) rotatable body (36) presses.

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