Patent Application
20170194123
The invention relates to a switching device including a fixed contact and a movable contact.
In most low-voltage switching devices that have a manual control knob, i.e. a manually operated element for closing the switch contacts and forming a conducting current path through the switching device, a movable switch contact mechanically coupled to the manual control knob is steadily brought closer to a switch contact fixed to the housing by means of the movement of the manual control knob until the two switch contacts mechanically abut one another. Accordingly, the contacts are opened, i.e. the switching device is deactivated, by moving the relevant manual control knob in a corresponding direction, resulting in the contacts being likewise separated steadily. By holding the manual control knob in any intermediate position, a user may even be able to keep the contacts in a corresponding intermediate position.
If there is an electric potential applied to the switching device in question, an arc is formed if the two switch contacts are close enough together. If the voltage is sufficiently low and as long as only loads that cause just a small flow of current over the switching device are connected, this generally does not cause any problems.
However, at higher DC voltages or higher DC currents, for example 600 V and 100 A, an arc of this kind, produced by the contacts being manually separated too slowly, can lead to significant damage to the switching device in question. If an accordingly higher current flows over the switching device in question as it is being switched off, the arc formed by the contacts being opened too slowly can not only lead to total failure of the switching device in question, but can also cause a fire.
Switching devices comprising a “snap-action deactivation function” are known. In these, when the device is switched off manually, the switch contacts are separated abruptly, regardless of how or how quickly a user operates a manual control knob. However, snap-action deactivation functions of this kind are common predominantly in the field of very large circuit breakers, as used for example in substations. Switching devices of this kind comprise spring accumulators that can be loaded separately and are used to close or open the contacts, but it is almost impossible to use this technology in the field of compact switching devices because the relevant technology cannot be integrated in the compact housings.
An aspect of the invention provides a switching device, comprising: a fixed contact, fixed to a housing, and a movable contact, the movable contact being arranged on a contact arm movably arranged in the switching device, the movable contact being configured to contact the fixed contact and being configured to form a conducting current path through the switching device; a latch, connected to the contact arm, the latch including a pawl and a pawl bearing surface, the pawl bearing surface including a latching point configured to latch the pawl to the pawl bearing surface; a hand lever, connected to the pawl using a first yoke, configured to bring the movable contact into contact with the fixed contact a snap-action deactivation mechanism configured for abrupt separation of the fixed and movable contacts following manual actuation; and a second yoke, mounted on the hand lever in such a way that actuation of the hand lever for separating the movable contact from the fixed contact releases the latching between the pawl bearing surface and the pawl.
The present invention will be described in even greater detail below based on the exemplary figures. The invention is not limited to the exemplary embodiments. All features described and/or illustrated herein can be used alone or combined in different combinations in embodiments of the invention. The features and advantages of various embodiments of the present invention will become apparent by reading the following detailed description with reference to the attached drawings which illustrate the following:
and
Therefore, an aspect of the invention provides a switching device of the type mentioned at the outset by which the aforementioned disadvantages can be prevented and which allows the switching device to be switched off safely, has a compact design and is simple to produce.
As a result, the switching device can be switched off safely, i.e. the contacts can be separated safely, regardless of the speed at which a user operates the hand lever. The switching device in question can be designed having compact dimensions and has a smaller number of necessary parts.
As a result, the switching device 1 can be switched off safely, i.e. the contacts 4, 6 can be separated safely, regardless of the speed at which a user operates the hand lever 7. The switching device 1 in question can be designed having compact dimensions and has a smaller number of necessary parts.
The invention being described here relates to an electrical switching device 1, the switching device 1 preferably being designed as a protective switching device or what is known as an automatic circuit breaker. Preferably, the switching device 1 is formed as a miniature circuit breaker or a power switch. Preferably, the switching device 1 is formed as a compact low-voltage protective switching device. According to the preferred design, the switching device 1 preferably comprises at least one trip 33.
The switching device 1 comprises at least one movable contact 4 and at least one contact 6 fixed to the housing. According to the preferred embodiment shown, the switching device 1 comprises a “double break”, and thus comprises two movable contacts 4 and two contacts 6 fixed to the housing, which are nevertheless assigned to just one contact gap.
When the at least one movable contact 4 is connected in an electricity-conducting manner to the at least one contact 6 fixed to the housing, there is an electricity-conducting current path through the switching device 1. The switching device 1 comprises connection terminals (not shown). If there is no such electricity-conducting connection through or over the switching device 1, this is described as deactivated or the deactivated state. If the corresponding conductive connection is produced, this is described as activated or the activated state. Accordingly, and as is normal, the transitions between the two states are referred to as activation and deactivation of the switching device 1. Closed contacts 4, 6 can be used synonymously for activated, as can open contacts 4, 6 for deactivated.
The at least one movable contact 4 is arranged on a movable contact arm 3. According to the preferred embodiment, the contact arm 3 shown separately in
On an end facing away from the at least one movable contact 4, the contact arm 3 comprises a contact arm extension 5, which is hook-shaped according to the preferred embodiment. According to the preferred embodiment, an end region 30 of the contact arm extension 5 is arranged substantially in parallel with a central piece 31 of the contact arm 3. Different angles can be provided according to the structural details of the switching device 1 in question.
Furthermore, the contact arm 3 comprises a bearing point 35 that is arranged between the at least one movable contact 4 and the contact arm extension 5 and is preferably in the form of a through-hole.
The contact arm 3 is designed as a part through which current flows directly, preferably comprising a copper-based alloy. According to the embodiment shown, the contact arm 3 is substantially a single piece, only the two movable contacts 4, as bearing surfaces, being made of a suitable contact material. The contact arm 3 can also be in multiple parts, and only the regions of the contact arm 3 through which current flows directly are designed comprising a highly conductive copper alloy, whilst the contact arm extension 5 is made of a different material. In practice, single-piece contact arms 3 have proven particularly successful in terms of both economical production and rigid construction.
The switching device 1 comprises what is known as a latch 2. The latch 2 is a mechanical assembly that controls the movements of the contact arm 3. In the preferred and shown embodiment, the latch 2 also comprises, in addition to the contact arm 3, a contact arm support 19, a pawl 20 and a pawl bearing surface 22.
The contact arm support 19, the contact arm 3 and the pawl bearing surface 22 are mounted in the latch 2 so as to be movable about a common latch rotary spindle 23, and each comprise corresponding through-holes or bearing points. The three parts are each arranged so as to be movable relative to one another. According to the embodiment shown, between the contact arm support 19 and the contact arm 3 there are arranged two leg springs 36 which cause the contact pressure when the contacts 4, 6 are closed and push the contact arm 3 against the contact arm support 19 when the contacts 4, 6 are open, as shown in
The pawl 20 is mounted on the contact arm support 19 so as to be movable about a pawl rotary spindle 21. The pawl 20 is connected to the hand lever 7 of the switching device 1 by means of a yoke 37 or a rod. The first yoke 37 can also be referred to or formed as a push rod.
The pawl bearing surface 22 comprises a latching point 24 for connecting to the pawl 20. In the “latched” state, i.e. when the pawl 20 engages on the pawl bearing surface 22, starting from a deactivated state of the switching device 1 movement of the hand lever 7 is transmitted to the pawl 20 by means of the first yoke 37. Since the pawl 20 cannot move or pivot away owing to the latching, the contact arm support 19 and the contact arm 3 are also moved as a result of the movement of the hand lever 7.
The pawl bearing surface 19 further comprises a window 27, through which the contact arm extension 5 reaches, and also a tripping extension 28 arranged in the switching device 1 opposite the tripping pusher 38 of the trip 33, as shown for example in
According to the particularly preferred embodiment, the switching device further comprises a snap-action activation mechanism 8.
By means of the snap-action activation mechanism 8 being described here, the proper functioning of the snap-action activation function can be reliably ensured over a long period of time or over a large number of activation operations. This can ensure that closing the contacts 4, 6, i.e. activating the switching device 1, leads to abrupt closure of the contacts 4, 6. In this way, the snap-action activation function can be carried out for many activation operations without noticeable changes. Since the contact arm catcher 11 does not have a lower hardness or surface hardness than the contact arm extension 5, signs of wear and tear, in particular loss of material, on the snap-action rocker can be prevented or reduced in such a way that the snap-action activation function is not affected. This can prevent material loss causing the retaining point of the snap-action activation mechanism 8 to constantly move until the snap-action rocker 10 can no longer firmly hold the contact arm extension 5 and the snap-action activation mechanism 8 becomes ineffective.
Above, it was described how, in the latched state, moving the hand lever 7 resulted in movement of the contact arm 3 and thus of the at least one contact. To prevent said parts continuously moving closer together, a snap-action activation mechanism 8 is provided, which firmly holds the contact arm 3 when the at least one movable contact 4 moves closer, in a predetermined manner, to the corresponding contact 6 fixed to the housing whilst the movement of the hand lever 7 continues.
The snap-action activation mechanism 8 comprises a snap-action rocker 10 that is mounted in the switching device 1 so as to be rotatable about a snap-action rocker rotary spindle 25. The snap-action rocker 10 comprises a contact arm catcher 11, which is intended or designed to contact the contact arm extension 5. In this case, the contact arm catcher 11 temporarily holds the contact arm extension 5 firmly at the insulating distance, and then releases it in a predeterminable manner. For this purpose, the snap-action rocker 10 is controlled by a first cam 9 of the hand lever 7, the hand lever 7 further comprising a second cam 26.
According to the embodiment shown, the snap-action rocker 10 is formed as a lever, the contact arm catcher 11 being arranged on a first lever arm 16 of the snap-action rocker 10, and a second lever arm 17 of the snap-action rocker 10, as an actuation extension 18, being designed to contact the at least one first cam 9 of the hand lever 7.
The snap-action rocker 10 is connected to the contact arm support 19 by means of an adjusting spring 29. In this case, the adjusting spring 29 in question, which is preferably in the form of a helical tension spring, engages on the snap-action rocker 10 on a pin 32 arranged slightly eccentrically. When the hand lever 7 is in the deactivated position, the second cam 26 pushes the second lever arm 17 of the snap-action rocker 10, and pushes the contact arm catcher 11 away from the contact arm extension 5. The adjusting spring 29 is substantially tension-free in this position. By moving the hand lever 7 toward the activated position, the second cam 26 is moved away from the second lever arm 17, making it possible for the snap-action rocker 10 to pivot. At the same time, the adjusting spring 29 is tensioned since the contact arm support 19 is moved away. As a result of the force now applied by the adjusting spring 29 and since it is able to move, the first lever arm 16 of the snap-action rocker 10, which arm carries the contact arm catcher 11, pivots toward the contact arm extension 5, which is likewise moving toward said arm, and the two then come to abut one another.
If the movement of the hand lever 7 continues, there is no longer any movement of the contact arm 3, which is held firmly on the contact arm catcher 11 by means of the contact arm extension 5.
In this case, the contact arm 3 preferably abuts the contact arm catcher 11 by means of a first contact arm retaining surface 14.
The contact arm catcher 11 has a surface hardness that is greater than or equal to a surface hardness of the contact arm extension 5, in particular of the first contact arm retaining surface 14. The surface hardness of the contact arm catcher 11 is thus at least as high as the surface hardness of the contact arm extension 5. In this respect, the surface hardness or simply the hardness refers to the resistance with which the bodies in question or the surfaces thereof counteract the penetration of a testing element. Owing to the hardness of the contact arm catcher 11 compared with the contact arm extension 5, it is possible to prevent excessive wear to the contact arm catcher 11.
In terms of the surface hardness of the contact arm extension 5, the regions or portions of the contact arm extension 5 that are in contact with the contact arm catcher 11 or come into contact therewith during operation have the corresponding surface hardness compared with the contact arm catcher 11.
Preferably, the hardness or surface hardness in question results from the Vickers hardness testing method.
In particular, the contact arm catcher 11 is designed comprising metal, the contact arm catcher 11 particularly being designed comprising steel.
Preferably, the contact arm catcher 11 is substantially rotationally symmetrical, thus allowing the contact arm extension 5 to slide off the contact arm catcher 11 in an effective and low-friction manner. In this respect, it has proven advantageous to form the contact arm catcher 11 as a round rivet and/or a tubular rivet 12. According to the particularly preferred embodiment shown of a switching device 1, the contact arm catcher 11 is formed as a tubular rivet 12 made of steel. In addition to being simple to produce, a rivet of this kind also has high dimensional stability, thus making it possible to prevent the insulating distance shifting over many switching cycles.
It is particularly preferable, and particularly simple when the contact arm catcher 11 is formed as a round rivet and/or a tubular rivet 12, for the contact arm catcher 11 to be mounted in the snap-action rocker 10 so as to be rotatable about its own contact arm catcher spindle. The contact arm extension 5 thus rolls along the contact arm catcher 11, whereby the durability of the assembly can be increased further.
Preferably, the end region 30 of the contact arm extension 5 has a rounding in the region intended to abut the contact arm catcher 11 when said extension is released. This can further reduce the wear to both the contact arm extension 5 and the contact arm catcher 11.
When the contact arm extension 5 is hook-shaped, as is preferred, the contact support extension 5 preferably engages behind the contact arm catcher 11 when the two parts are engaged. In the process, the contact arm catcher 11 is designed accordingly to allow such engagement from behind. Accordingly, the contact arm catcher 11 preferably has a bar-like construction that links two side legs 39 of the snap-action rocker 10. This is provided when the contact arm catcher 11 is rotationally symmetrical, as is preferred and as shown in the drawings. In this case, the contact support extension 5 engages behind the contact arm catcher 11.
Preferably, the snap-action rocker 10 also comprises a limit stop 13 in the region of the contact arm catcher 11, and, when the contact arm extension 5 engages with the snap-action rocker 10, the first contact arm retaining surface 14 abuts the contact arm catcher 11 and a second contact arm retaining surface 15 abuts the limit stop 13. In the process, the second contact arm retaining surface 15 is arranged substantially normally to the first contact arm retaining surface 14. The limit stop 13 prevents the contact arm extension 5 entering the snap-action rocker 10 too far or too deeply. This can further ensure the intended function of the snap-action activation.
The switching device comprises a snap-action deactivation mechanism 40 for the abrupt separation of the contacts 4, 6 following manual actuation. In this case, the snap-action deactivation mechanism 40 comprises a second yoke 41, which can also be formed or referred to as a push rod or rod, similarly to the first yoke 37, and which second yoke 41 is mounted on the hand lever 7. The second yoke 41 interacts with the pawl bearing surface 22 in such a way that the latching between the pawl bearing surface 22 and the pawl 20 is released when the hand lever 7 is operated to separate the contacts 4, 6.
In this respect,
Starting from a position corresponding to the activated state of the switching device 1, the hand lever 7 in question is moved toward a position corresponding to the deactivated state of the switching device 1, the second yoke 41 moving the pawl bearing surface 22 in such a way that the latching between the pawl 20 and the pawl bearing surface 22 is released. The latch 2 in question is thus “tripped” by means of the second yoke 41 since the second yoke 41 moves the pawl bearing surface 22 according to an actuation by the tripping pusher 38 of the trip 33.
It should be noted that the switching device 1 according to the invention can trip in the sense of “free tripping” even in the case of a hand lever 7 that is fixed in the position corresponding to the activated state, and that the contacts 4, 6 are separated in the process. The snap-action deactivation mechanism 40 according to the invention relates to the separation of the previously closed contacts 4, 6 brought about manually by operation of the hand lever 7. Irrespective of the term “manual”, this operation can also be carried out by means of an external mechanical actuator that drives the hand lever 7.
According to the preferred embodiment, the pawl bearing surface 22 comprises a guide slot 53 in which the second yoke 41 is arranged so as to be movable in some regions. The second yoke 41 is not rigidly connected to the pawl bearing surface 22, but rather arranged in said guide slot 53 in a longitudinally movable manner. At the same time, the guide slot 53 is preferably formed by two stub-like extensions 49, though it can also have a different design.
The guide slot 53 is preferably arranged in a snap-action tripping extension 55 of the pawl bearing surface 22. The pawl bearing surface 22 is preferably in the form of a lever rotatably or pivotally mounted on the latch rotary spindle 23. One lever arm of this lever-like pawl bearing surface 22 is formed by the tripping extension 28. The second lever arm is formed by the snap-action tripping extension 55, the latch rotary spindle 23 being arranged between the tripping extension 28 and the snap-action tripping extension 55.
The pawl bearing surface 22 preferably also comprises a snap-action tripping stop 54 to be actuated by the second yoke 41, which snap-action tripping stop 54 is preferably arranged at the guide slot 53. In particular, the snap-action tripping stop 54 is formed by one of the preferably two stub-like extensions 49 that together form the guide slot 53.
The second yoke 41 further comprises a shoulder or a hook-shaped end portion 48 for actuating the snap-action tripping stop 54.
The hand lever 7 preferably comprises a first hand lever part 42 and a second hand lever part 43. The handle 45 of the hand lever 7 is arranged on the second hand lever part 43. The two hand lever parts 42, 43 are rotatably arranged about the same hand lever rotary spindle 44. The first yoke 37 is mounted on the first hand lever pat 42 and the second yoke 41 is mounted on the second hand lever part 43.
The first hand lever part 42 and the second hand lever part 43 are formed at least in some regions as rotationally symmetrical bodies. The first and second cams 9, 26, which have already been described in connection with the snap-action activation function, are arranged on the second hand lever part 43. The bearing of the first yoke 37 is also arranged in the region of the second cam 26.
The first hand lever part 42 is preferably mounted inside the second hand lever part 43 in a coaxial manner at least in some regions. In the process, the two hand lever parts 42, 43 are pre-tensioned in terms of their basic position by means of a hand lever spring 46 arranged inside the hand lever 7.
The first hand lever part 42 is rotatable relative to the second hand lever part 43 by a predeterminable angular range. Preferably, the angular range and a length of the second yoke 41 are designed such that the latching between the pawl bearing surface 22 and the pawl 20 is released when the hand lever 7 is arranged in the region of a middle position between an activation position of the hand lever 7 and a deactivation position of the hand lever 7. In this context, the position of the hand lever 7 is preferably determined by the position of the handle 45. In this way, it is possible to produce a particular range within which the handle 45 and thus also the second hand lever part 43 can be moved, without the contacts 4, 6 being separated. This is important in practice in order to prevent slight contact of the handle 45 leading to the switching device 1 being switched off. The middle position is preferably considered to be the middle angular position of the handle 45 between the two positions that correspond to an activated switching device 1 and a deactivated switching device 1. Preferably, said range is ±15° around the middle position. The details described preferably refer to the handle 45 or second hand lever part 43 passing said position. The second hand lever part 43 can thus be moved as far as to the particular position without the contacts 4, 6 being separated. If the second hand lever part 43 moves beyond this position, the contacts 4, 6 are separated abruptly.
In the preferred embodiment, the second hand lever part 43 comprises a segment-like cut-out 47, as shown in
A catch projection 50 is arranged on the first hand lever part 42. Preferably, the catch projection 50 is arranged in the region of the first cam 9, or adjacently to the first cam 9. When the switching device 1 is activated, the first cam 9 releases the contact arm 3, and so the contacts 4, 6 are closed. Next to the first hand lever part 42, or therebelow in the illustrations, a pivotally mounted rocking lever 51 is arranged as an additional part of the latch 2. The rocking lever 51 engages in the catch projection 50 and holds the first hand lever part 42 firmly in position. The second hand lever part 43 can move relative to the first hand lever part 42 being held firmly by the rocking lever 51, and so the pawl bearing surface 22 is deflected away and the contacts 4, 6 are thus separated when a particular position is passed. The segment-like cut-out 47 on the second hand lever part 43 can thus be designed or sized such that further rotation of the second hand lever part 43 is accordingly possible, without the second hand lever part 43 striking the second cam 26 first.
When the contacts 4, 6 are separated, the contact arm support 19 is also moved. A contact arm support extension 52 is arranged on the contact arm support 19 and pushes the rocking lever 51 away from the catch projection 50 when the contacts 4, 6 are open. During the operation for opening the contacts 4, 6, the rocking lever 51 is thus lifted off the catch projection 50, as a result of which the first hand lever part 42 can pivot back relative to the second hand lever part 43 and the first cam 9 abuts the segment-like cut-out 47 again.
The rocking lever 51 is spring-loaded accordingly, and so it is pushed toward the first hand lever part 42.
While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. It will be understood that changes and modifications may be made by those of ordinary skill within the scope of the following claims. In particular, the present invention covers further embodiments with any combination of features from different embodiments described above and below. Additionally, statements made herein characterizing the invention refer to an embodiment of the invention and not necessarily all embodiments.
The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B, and C” should be interpreted as one or more of a group of elements consisting of A, B, and C, and should not be interpreted as requiring at least one of each of the listed elements A, B, and C, regardless of whether A, B, and C are related as categories or otherwise. Moreover, the recitation of “A, B, and/or C” or “at least one of A, B, or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B, and C.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 107 265.0 | May 2014 | DE | national |
This application is a U.S. national stage application under 35 U.S.C. §371 of International Application No. PCT/EP2015/060988, filed on May 19, 2015, and claims benefit to German Patent Application No. DE 10 2014 107 265.0, filed on May 22, 2014. The International Application was published in German on Nov. 26, 2015, as WO 201 5/1 771 44 A1 under PCT Article 21(2).
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/060988 | 5/19/2015 | WO | 00 |
