Patent Grant
9171684
The present application hereby claims priority under 35 U.S.C. §119 to German patent application number DE 10 2012 203 294.0 filed Mar. 2 2012, the entire contents of which are hereby incorporated herein by reference.
At least one embodiment of the invention generally relates to a circuit breaker having a latching mechanism.
Latching mechanisms comprise on the one hand a switching mechanism for opening and closing a switch contact which is in operative contact with a tensioning element, and on the other hand an unlatching mechanism by which, in response to a tripping signal, the tensioning element can be transferred from a tensioned state into an at least substantially relaxed state in order in this way to open the switch contact.
Circuit breakers are special switches which are usually designed for high currents. These switches are not only able to switch operating currents and low overload currents, but in the event of errors can also switch on high overload currents and short-circuit currents, hold these fault currents for a predetermined time and switch them off again. Depending on embodiment variant, circuit breakers are implemented as single-pole or multi-pole.
Circuit breakers generally comprise so-called latching mechanisms which, when unwanted operating states occur, in particular in the case of short circuits, cause an electric circuit to be disconnected.
A latching mechanism is a mechanical apparatus which preferably enables an electric circuit to be disconnected. Toward that end the force of a tensioned spring which was tensioned by means of a tensioning mechanism at the time of switching on is usually released in order to open the switch contact. The typical tripping criterion is a current with a presettable current intensity by means of which the latching mechanism action is tripped with the aid of an electromagnet or of a self-heating bimetallic strip.
A circuit breaker latching mechanism comprises two essential areas. On the one hand, a switching mechanism is provided by way of which an electrical switch contact is opened and closed upon exposure to spring force. On the other hand, a latching mechanism of said kind comprises an unlatching mechanism which, when a tripping criterion is fulfilled, releases the energy stored in a spring of the switching mechanism, as a result of which the latching mechanism is tripped and the electrical switch contact is opened.
In this connection, solutions are known from the prior art which are intended to prevent the latching mechanism being tripped in the OFF position. Thus, for example, DE 693 06 822 T2 describes a circuit breaker latching mechanism comprising a so-called test button, the actuation of which ensures that the latching mechanism also does not trip in the OFF position. To this end, in the OFF position of the latching mechanism, the tensioning bolt mounted in the actuating lever slides onto a blocking contour on the tension lever, so that the latter is locked and in no event releases the latching mechanism or the switch. This makes it possible to press the test button and then actuate the tripping shaft without the latching mechanism being tripped. In this way the switching mechanism is kept in a pretensioned state even in the case of unintentional tripping.
The inventors discovered that an aspect of the above-described technical solution is the fact that a blocking contour is provided on the tension lever, the blocking contour being required in order to lock the unlatching mechanism in the OFF position of the latching mechanism. Hence, the geometry of the tension lever and its pivot point are not freely selectable but instead the blocking contour provided on the blocking lever always has to be taken into account. Accordingly, the known locking mechanisms for the OFF positions should generally only be used for a limited number of latching mechanisms each having the same latching mechanism kinematics.
On the basis of this, an embodiment of the invention is directed to a latching mechanism of a circuit breaker in such a way that the latching mechanism remains in the OFF position even following unintentional tripping in the tensioned position. The technical solution to be disclosed is intended to be implemented using relatively simple structural means and at reasonable cost. In addition it should be possible to use the latching mechanism for virtually any type of related latching mechanism kinematics.
A latching mechanism is disclosed for a circuit breaker. Advantageous embodiment variants of the invention are the subject matter of the dependent claims and will be explained in more detail in the following description, sometimes with reference to the figures.
A circuit breaker is disclosed with a latching mechanism comprising a switching mechanism for opening and closing a switch contact which is operatively connected to a tensioning element, and an unlatching mechanism by way of which, in response to a tripping signal, the tensioning element can be transferred from a tensioned into an at least substantially relaxed state in such a way that the switch contact is opened thereby. The tensioning element is here indirectly coupled to a tension lever which can be locked or released as a function of a position of a blocking pawl of the unlatching mechanism. The tension lever also comprises a blocking mechanism by means of which, in an OFF position of the latching mechanism in which the switch is open and the tensioning element is tensioned, tripping of the tension lever is prevented despite a tripping signal.
The invention is described in more detail below, without restricting the general inventive concept, with the aid of example embodiments and with reference to the figures, in which:
The present invention will be further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the particular embodiments described herein are only used to illustrate the present invention but not to limit the present invention.
Accordingly, while example embodiments of the invention are capable of various modifications and alternative forms, embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments of the present invention to the particular forms disclosed. On the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of the invention. Like numbers refer to like elements throughout the description of the figures.
Specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments of the present invention. This invention may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments of the present invention. As used herein, the term “and/or,” includes any and all combinations of one or more of the associated listed items.
It will be understood that when an element is referred to as being “connected,” or “coupled,” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” or “directly coupled,” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between,” versus “directly between,” “adjacent,” versus “directly adjacent,” etc.).
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments of the invention. As used herein, the singular forms “a,” “an,” and “the,” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the terms “and/or” and “at least one of” include any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, term such as “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein are interpreted accordingly.
Although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, it should be understood that these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or section from another region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present invention.
A circuit breaker is disclosed with a latching mechanism comprising a switching mechanism for opening and closing a switch contact which is operatively connected to a tensioning element, and an unlatching mechanism by way of which, in response to a tripping signal, the tensioning element can be transferred from a tensioned into an at least substantially relaxed state in such a way that the switch contact is opened thereby. The tensioning element is here indirectly coupled to a tension lever which can be locked or released as a function of a position of a blocking pawl of the unlatching mechanism. The tension lever also comprises a blocking mechanism by means of which, in an OFF position of the latching mechanism in which the switch is open and the tensioning element is tensioned, tripping of the tension lever is prevented despite a tripping signal.
The blocking mechanism of the tension lever comprises a rocker arm which is fastened movably on the tension lever.
Hence, a feature of a latching mechanism according an embodiment of the invention is that a movable rocker arm is provided on the tension lever, which rocker arm, in the OFF position, reliably prevents tripping of the latching mechanism. The rocker arm is in this case embodied in such a way that it is used exclusively for blocking the latching mechanism in the OFF position.
As soon as the electrical switch contact is switched off or opened, the circuit breaker latching mechanism is transferred into the OFF position, wherein the tensioning element of the switching mechanism still remains in the tensioned state. The rocker arm mounted rotatably on the tension lever is now used to ensure that the tension lever is locked in such a way that, even in the event of an actuation of the tripping shaft, the tension lever does not move and hence the tensioning element of the switching mechanism is also not relaxed.
In an embodiment of the invention, a tensioning bolt mounted in the actuating lever slides onto a blocking contour of the rocker arm as soon as the latching mechanism is transferred into the OFF position upon the opening of the switch contact. Since the torque now introduced into the tension lever via the rocker arm is greater than the torque introduced via the tension spring of the switching mechanism, the tension lever in the OFF position is preferably pressed downward, so that the end of the blocking pawl no longer bears on the stopping face of the tension lever, which is used for the latching of the two components. Since in this case the tension lever is locked and the blocking pawl is relaxed and no longer in engagement with the tension lever, the test button can now be pressed or the tripping shaft actuated, without the latching mechanism being tripped.
As soon as the tripping shaft of the unlatching mechanism has been actuated, regardless of whether this takes place via a tripping action or actuation of the test button, the latching mechanism or the unlatching mechanism has to undergo a reset operation before being transferred back to the ON position. With a reset operation of this kind, the tripped latching mechanism, in particular the unlatching mechanism, is reactivated.
Preferably the rocker arm is mounted movably on the tension lever in such a way that, as soon as a reset operation is initiated, a reset contour on the tension lever becomes free and the tensioning bolt mounted in the actuating lever can slide over the reset contour. This causes the tripping shaft to be returned to an initial tensioned state. After the end of the reset operation, the latching mechanism can, if required, be returned to the ON position by actuating the actuating lever.
In a special embodiment variant of the invention it is provided that the rocker arm is mounted on the tension lever in such a way that the rocker arm is at least partially folded back behind the tension lever so that the reset contour on the tension lever is freely accessible to the tensioning bolt.
The forced resetting of the rocker arm effected by the tensioning bolt ensures the free movement/smooth running of the component in order to return the rocker arm to the engagement position on the subsequent swinging-in of the blocking pawl. According to a special development, the tension lever is implemented in at least two parts and comprises two plane-parallel side parts between which the rocker arm is retracted immediately before or at the start of the reset operation.
The unlatching mechanism 3 is provided in order on the one hand to hold the spring 4 reliably in the tensioned state and on the other hand to enable reliable and rapid tripping of the latching mechanism to be ensured.
The connection between the switching mechanism 2 with the tension spring 4 and the unlatching mechanism 3 is established by way of a tension lever 5 which can be blocked or released by the unlatching mechanism 3 as required. As soon as the tension lever 5 is released by the unlatching mechanism 3, the spring 4 relaxes and the electrical switch contact opens.
The catch spring 10 is an essential component of the unlatching mechanism 3, said spring acting on the blocking pawl 8 in such a way that the end of the blocking pawl 8 is moved toward a stopping face of the tension lever 5 provided for this purpose in order to lock the tension lever 5. In addition, a tripping shaft 9 is provided in the unlatching mechanism 3 and when a tripping criterion is fulfilled, in particular as soon as the current in the switch reaches a predetermined current intensity, said tripping shaft is set into a rotary or swiveling motion by an actuator. The movement of the tripping shaft 9 causes it to come into contact with the blocking pawl 8 in such a way that the blocking pawl 8 is also swiveled and hence the force from the end of the blocking pawl 8 acting on the stopping face of the tension lever 5 is reduced. The reduction of the force from the blocking pawl 8 acting on the stopping face of the tension lever 5 also causes the locking of the tension lever 5 to be released, the spring 4 to be relaxed and the switch contact to open.
The different switching states of the latching mechanism 1 are explained in detail below.
In the ON position, the switch is closed, the spring 4 tensioned and the latching mechanism 1 is in the blocked state.
In addition, the unlatching mechanism 3, and hence also the latching mechanism 1, is in the tensioned state, with the end 12 of the blocking pawl 8 being in contact with the outer circumference of a roller 7 mounted rotatably on the tension lever 5 in the area of the stopping face 13. The blocking pawl 8 hence locks the tension lever 5 in the position shown so that the spring 4 is tensioned and the electrical switch contact is closed.
In order to transfer the latching mechanism into the OFF position, the actuating lever 6 is moved to the right so that a tensioning bolt 11, which is mounted in the actuating lever 6, is brought into contact with the blocking contour 18 of the rocker arm. Due to the rocker arm 17, the torque introduced via the actuating lever 6 into the tension lever 5 is greater than the torque of the tensioning elements of the switching mechanism 2 which are implemented as tension springs 4. This causes the tension lever 5 to be pressed slightly downward and the latching between the end 12 of the blocking pawl 8 and the stopping face 13 of the tension lever 5 to be relaxed. As
To supplement
Regardless of whether the test button has been actuated or the latching mechanism 1 has been tripped in response to a tripping signal, it is necessary for a reset operation to be performed first in order to reactivate the latching mechanism 1 and in this case in particular the unlatching mechanism. In this connection,
To initiate the reset operation, the actuating lever 6 is moved by means of the handle in the direction of the arrow toward the right. This causes the tensioning bolt 11, which is mounted in the actuating lever 6, to move along the reset contour 19 of the tension lever 5. Here, the reset contour 19 of the tension lever 5 is freely accessible to the tensioning bolt 11, since the rocker arm 17 is swiveled downward between the two side parts 14, 15 of the tension lever 5.
The movement of the tensioning bolt 11 along the reset contour 19 of the tension lever 5 causes said lever to be pressed downward. To supplement this,
Finally,
By way of the rocker arm 17 provided on the tension lever 5 of a latching mechanism 1 according to an embodiment of the invention it is reliably ensured that, in the OFF position of the latching mechanism 1, the test button can be pressed or the tripping shaft actuated without the latching mechanism or the switch being tripped.
Owing to the provision of the rocker arm 17 on the tension lever 5, which rocker arm 17 is required exclusively to prevent the latching mechanism being tripped in the OFF position, the position of the pivot point and the blocking contour are freely selectable. This enables the rocker arm 17 to be used in different latching mechanisms 1 irrespective of the latching mechanism kinematics in each particular case.
The example embodiment or each example embodiment should not be understood as a restriction of the invention. Rather, numerous variations and modifications are possible in the context of the present disclosure, in particular those variants and combinations which can be inferred by the person skilled in the art with regard to achieving the object for example by combination or modification of individual features or elements or method steps that are described in connection with the general or specific part of the description and are contained in the claims and/or the drawings, and, by way of combinable features, lead to a new subject matter or to new method steps or sequences of method steps, including insofar as they concern production, testing and operating methods.
References back that are used in dependent claims indicate the further embodiment of the subject matter of the main claim by way of the features of the respective dependent claim; they should not be understood as dispensing with obtaining independent protection of the subject matter for the combinations of features in the referred-back dependent claims.
Furthermore, with regard to interpreting the claims, where a feature is concretized in more specific detail in a subordinate claim, it should be assumed that such a restriction is not present in the respective preceding claims.
Since the subject matter of the dependent claims in relation to the prior art on the priority date may form separate and independent inventions, the applicant reserves the right to make them the subject matter of independent claims or divisional declarations. They may furthermore also contain independent inventions which have a configuration that is independent of the subject matters of the preceding dependent claims.
Further, elements and/or features of different example embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims.
Still further, any one of the above-described and other example features of the present invention may be embodied in the form of an apparatus, method, system, computer program, tangible computer readable medium and tangible computer program product. For example, of the aforementioned methods may be embodied in the form of a system or device, including, but not limited to, any of the structure for performing the methodology illustrated in the drawings.
Example embodiments being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
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