This application claims priority under 35 U.S.C. §119 to European Patent Application No. 12171421.6 filed in Europe on Jun. 11, 2012, the entire content of which is hereby incorporated by reference in its entirety.
The present disclosure relates to an electric current switching apparatus.
Many issues affect designing of an electric current switching apparatus. The design goals include, for instance, ease of assembly of the switch, possibility to assemble various switch types, security of use of the switch, fast connecting and disconnecting of the contacts and efficient quenching of an arc firing when the contacts are separated.
A rotary switch module is disclosed, comprising: a first stationary contact; a second stationary contact; a movable contact for making an electrical connection between the first stationary contact and the second stationary contact; a rotary actuator for rotating the movable contact, wherein the rotary actuator includes on a surface a first indication indicating an open position of the first and second stationary contacts, and a second indication indicating a closed position of the first and second stationary contacts; a first window indicating the first indication; and a second window separate from the first window indicating the second indication.
In the following, the invention will be described in greater detail by way of preferred exemplary embodiments with reference to the accompanying drawings, in which:
Exemplary embodiments of the present disclosure can provide an improved electric current switch.
Electric switches can include a few switch modules/poles, which are stacked together to build multi-pole switches. Each module may comprise an insulating housing, which houses the electrical components of the switch modules. Each module housing may comprise a first housing half and a second housing half made of plastic, for instance, to be assembled together to form a switch module. The housing modules may be substantially rectangular.
The switch may also comprise a quenching chamber housing one or more quenching plates 140 used for quenching an arc that fires between the contacts when the movable contact is disconnected from the stationary contact(s).
The stationary contact 110 comprises a connection portion 110A to be connected to an external conductor. The connection portion 110A is for example arranged substantially perpendicularly to the wall of the housing 102. The stationary contact can further comprise a contact portion 110B to be connected to the movable contact. It can be seen that the connection portion 110A and the contact portion 110B are, for example, arranged to an angle with respect to each other; that is they are not parallel with each other. Similarly in the stationary contact 112, the connection portion and the contact portion are arranged in an angle to each other, which tilting of the two is arranged inside the housing.
In the illustrated exemplary embodiment, the first stationary contact 110 is pivotally connected to the movable contact. The stationary contact remains stationary during the operation of the switch. The movable contact pivots between the two extreme positions shown in
In an exemplary embodiment, the connection portions of the stationary contacts 110, 112 are parallel and aligned with each other; that is, they are at the same plane. As the contact portions of the stationary contacts point substantially towards the rotation axis of the rotary actuator, the rotation axis of the actuator 120 lies below the plane of the connection portions of the stationary contacts 110, 112.
As the bold arrows indicate in
In the current path, the angle of the branches of the V is at its smallest when the movable contact barely touches the second stationary contact 112. At that point, the magnetic forces in the branches of V, that is, in the first stationary contact 110 and in the movable contact 130, oppose each other, and are at their greatest, causing the movable contact to turn away from the first stationary contact. Thereby the force alleviates the making of the contact of the movable contact and the second stationary contact. This phenomena can be especially advantageous in closing the switch against great short-circuit currents. If an exemplary nominal current of the switch is 4 kA, the short-circuit current may be as high as 80 kA, for instance. At such great currents, the V-profiled current path can greatly assist in closing the switch.
Thus, in the switch, the angle between the movable contact and the first stationary contact is greater when the switch is closed than the angle between the two when the switch is open. Here the angle between the two refers to the smaller angle, which is for example below 180 degrees if the contacts are assumed to originate from the pivot point between the two. For example, the angle between the two is less than 170 degrees when the switch is closed, and more preferably between 110 to 160 degrees in exemplary embodiments.
The movable contact 130 makes an electrical connection with the stationary contact by receiving the stationary contact between the first and second contact blades 131, 132. The side 132C of the contact blade 132 that receives the stationary contact may be slanted to assist in receiving the stationary contact between the blades. The contact blade also comprises an assembly hole 132A for receiving the assembly pin 138 when the movable contact is assembled, and a pivoting hole 132B for receiving a pivoting pin when the movable contact is arranged together with stationary contact.
The movable contact may comprise first and second cover portions 133, 134, where the first cover portion 133 is placed next to the first contact blade 131, and the second cover portion 134 is placed next to the second contact blade 132. The contact blades 133, 134 may be similar to each other and when the movable contact is assembled, the cover portions 133 and 134 come mutually in opposite rotation position to each other.
The cover portion 133 comprises a side portion 133C covering and protecting the contact blade from the side. The cover portion 133 may be symmetric such that there is a similar side portion on the other side of the cover portion. On the top side, the cover portion may comprise an assembly hole 133A for receiving the assembly pin 138, and a pivoting hole 133B for receiving the pivoting pin.
The movable contact also comprises a spring element 136 on one side of the movable contact. Alternatively, another spring element may also be provided on the other side of the movable contact. The spring element can comprise an assembly hole 136A for receiving the assembly pin 138, and a receptacle 136B for receiving the pivoting pin. As can be seen, the assembly hole converges to the right; that is, the hole is at its greatest on the left in
The assembly pin 138 can comprise a separation portion 138A, which defines the distance between the contact blades 131, 132. That is, the diameter of the separation portion 138A is greater than the diameter of the assembly hole 132A of the contact blade 132, whereby the contact blades set against the ends of the separation portion 138A.
The assembly pin 138 can further comprise a first contact blade portion 138B and a second contact blade portion 138C, which are to be placed into the assembly holes of the contact blades; that is, the diameter of the assembly hole 132A is greater than the diameter of the contact blade portion 138B, which in turn is greater than the assembly hole 133A of the cover. When assembled, the cover thus stops the contact blade portion 138B and sets against the end of it. In an exemplary embodiment, the thickness of the contact blade 131 is slightly greater than the length of the contact blade portion 138B. Thereby if the contact blade wears and becomes thinner, there is some clearance and the contact spring can still apply a pressing force for pressing the contact blade against the separation portion 138A of the pin 138.
As
When the movable contact is assembled, the connection pin is put through the assembly holes in the contact blade 131, cover portion 133 and the contact spring 136A. The cover portion 138B is locked to the contact pin by moving the cover portion to the right, whereby the cover portion sets into the small end of the assembly hole 133B of the cover portion. The spring element 136 is locked to the contact pin by moving the contact pin to the left, whereby the cover portion of the pin enters the smaller end of the assembly hole 136A of the spring.
The contact blades may for example be made of the copper and be coated with silver, for instance. The cover portion, the spring element and the assembly pin may for example be made of steel to obtain more contact power due to magnetic forces.
The illustrated structure can provide an exemplary advantage in that the contact blades can be made straight, and there is no need for provision of projections on the surfaces of the contact blades to keep them separated.
When the stationary contact 110 and the movable contact 130 are assembled together, the movable contacts are set in the proximity of the projections 114A, 114B and 114C. Each of the projections is provided for mounting one of the shown three contact blade structures to the stationary contact. The contact blades of each contact blade structure are set to opposite sides of the respective projection such that the pivoting holes of the contact blade structures coincide with the pivoting holes 116 in the projections 114A, 114B and 114C. When the holes are aligned with each other, a pivoting pin 135 can be pushed through all the holes, whereby the contact blade structures become pivotally connected to the stationary contact 110.
Thereafter, the assembled structure of the stationary contact and the movable contact can be assembled to the rotary actuator 120. This is carried out pushing the assembled structure partly through the actuator. The actuator 120 comprises two apertures, one on each side of the actuator. In
In the assembly of the stationary contact and the movable contact to the rotary actuator, the movable contacts are pushed in the actuator from the first aperture 122 such that each of the contact blade assemblies sets to their respective spaces separated by walls 124. The contact blades are pushed further such that their ends exit the actuator from the apertures 127A to 127C. At that stage, the projections of the stationary contact have entered the interior of the actuator. When the assembly is ready, the pivoting pin 135 sets inside the actuator, for example to the rotation axis of the actuator 120.
In an exemplary use, the stationary contact can be arranged stationary to the housing, but the rotary actuator may rotate within the housing. The rotation of the rotary actuator with respect to the stationary contact is defined by the upper wall 126 and the lower wall 128. In one extreme rotary position of the actuator 120, that is the open position, the top wall 126 of the actuator 120 sets against the top surface of the contact portion 1108 of the stationary contact 110. In the other extreme rotary position of the actuator, that is the closed position of the switch, the lower wall 128 of the aperture sets against the bottom surface 110C of the stationary contact 110. The edges of the aperture 122 thus define the rotary angle of the rotary actuator 120. On the other side of the rotary actuator, the second apertures 127A to 127C can be dimensioned such that the movable contacts, or the contact blade assemblies, are substantially fixed/immovable with respect to the rotary actuator 120, that there is tight fitting between the two. The movement of the movable contact(s) thus follows the rotation of the rotary actuator.
The assembly is completed by pushing the connection pin 135 through holes provides in the projections of the stationary contact, and the movable contacts. When the movable contacts are mounted to the stationary contact with the pin, the movable contacts are freely pivotable about the stationary contact. The amount of mutual pivoting of the movable contact and the stationary contact is, for example, limited by the rotary actuator shown in
The indications may, for example, be provided on a wall section of the actuator, which wall section is between the first and second apertures of the actuator. The indications may be provided on the wall by any known means, such as by writings, carvings, or by attaching a sticker, for instance. The indications, such as text, symbol or colour indications, are for example provided on the actuator perpendicularly to the rotation direction of the actuator.
The support structure is positioned inside the housing next to a wall of the housing and may be substantially aligned with the centre of the actuator in a longitudinal direction of the module. The support structure may be positioned between the windows 104, 106 such that the base of the support structure forms at least part of a housing wall residing between the windows. The windows may be implemented as apertures in the housing, to which housing a transparent plastic or glass window can be arranged.
During an exemplary use, the support structure 108 hides the text OPEN behind it such that it is substantially invisible from the first window when the switch is in the closed position. When the switch is rotated to the open position, the text OPEN emerges from behind the support structure 108 and is shown in the first window 104, which is closer to the first stationary contact 110 than the second window 106. When the switch is in the OPEN position, the text CLOSED is situated behind the support structure 108 and is substantially invisible from the second window 106.
In this way the security of the device can be greatly improved and combined when providing sufficient mechanical support for the module. The support section covers the indication that is not relevant at the particular moment, and the rotation of the rotary actuator is utilized in providing the indication.
In an exemplary embodiment, the quenching plate 142 and the other quenching plates are straight such that their two surfaces are direct plane surfaces. In another exemplary embodiment, the quenching plate(s), such as the first quenching plate 142, has a tilted portion 142A at the back of the plate. The tilted rear portion 142 is thus divergent from the general plane level of the plate. The first quenching plate 142 is mounted in such a way to the housing 102 that its protrusion 142A pointing towards the stationary contact 112 is in contact with the stationary contact.
The quenching plate 142 comprises a front portion located close to the contact area of the movable contact 130 and the stationary contact 112, and a rear portion that resides at a distance from the contact area, and the contact between the quenching plate 142 and the stationary contact is arranged at the rear portion of the quenching plate 142. The contact area between the two can be as small as possible to ensure catching the arc at the rear portion of the plate. The principal plane of the quenching plate and the stationary contact may be mutually slightly divergent such as to ensure that the contact area is small. In this way, the burning arc can be quickly moved away from the contact area. As
It can be seen that the stationary contact 112 comprises a contact portion to be contacted by the movable contact 130, and a connection portion to be contacted by a conductor, wherein the contact portion is divergent from the connection portion. The contact between the quenching plate 142 and the stationary contact 112 is arranged at the contact portion close to the area where the contact portion turns to the connection portion. In this way, the quenching plates can keep their position such that their plane surface points substantially towards the rotation axis of the rotary actuator, whereby the quenching plates can always be perpendicular to the movable contact 130 when it moves away from the stationary contact 112.
The exemplary embodiment achieves this by having a projection 109 at an aperture of the housing where the stationary contact 112 is to be mounted.
If assumed that the switch to be equipped would have a smaller nominal current, the stationary contact could be made thinner. In such as case, the stationary contact can be without a recess 118 as the shown stationary contact. The stationary contact would then lie on the projection 109.
The housing may comprise another projection, which fills the recess 117 in the stationary contact. This joint can prevent the stationary contact from moving in a longitudinal direction of the stationary contact; that is, to the left and right in the shown embodiment. Such a recess 117 may be provided both in the thick and thin stationary contacts.
In the exemplary situation of
By way of an example, if the rotary mechanism of a switch breaks, a rotary actuator may not rotate even if the rotation mechanism is rotated. It may then occur that the switch is closed even if the rotation mechanism indicates that the switch would be open. The illustrated solution can avoid this, as the actual rotation position of the rotary actuator can always be verified.
The opening for housing the actuator may be placed substantially in the middle of the module in the left-right direction in
The aperture can comprise a first projection 109 which allows mounting of stationary contacts of two different thicknesses to the aperture. Despite the different thicknesses, the stationary contacts have the same width. The width of the stationary contacts is substantially double the width of the aperture 103 shown as half of the stationary contact sets into the aperture 103 and the other half to the other module housing to be assembled to the shown housing.
It can be seen that the projection is placed, in the embodiment of
In a thicker stationary contact, there is a recess corresponding to and receiving the projection 109, whereby the rest of the stationary contact sets against the bottom surface of the recess 103. The thinner stationary contact has no such recess, whereby the bottom of the thinner stationary contact sets against the top surface of the projection 109.
Both the thin and thick stationary contacts may comprise a vertical recess for receiving the projection 107. The exemplary vertical and horizontal projections 107, 109 form substantially a letter T. They may extend equally long away from the side wall surface of the aperture.
There is also another exemplary advantage. In a switch having a high nominal current, there may be a desire to connect the stationary contact outside the switch module to one or more additional current conducting rails, which may have thicknesses equal to the thickness of the stationary contact. The holes provided in the stationary contact shown in
It can be especially advantageous to arrange the horizontal projections 109 such that they are on the side of the aperture 103 that is closer to the middle line of the switch housing. In
In the
This solution provides an exemplary advantage that mounting of the window element is simple as there is need only for one window element. Furthermore, the mounting of the window element is mechanically very strong, as the window element is mechanically supported at the middle of the window.
The projection 209 is formed within the interior of the aperture. The interior of the aperture refers here to the space at the aperture which is between the inner and outer walls of the housing. Similarly, a recess of the stationary contact that receives the projection is provided such that the recess resides within the interior of the aperture when the stationary contact is mounted to the housing.
The embodiment of
The thicker stationary contact 310 can have an additional first recess 318 for receiving the first projection 209 of the housing.
Thus, both stationary contacts of
It is noted that both stationary contacts have the same width, which in
In a further embodiment, stationary contacts may be mounted to the switch housing by providing compensation means on the stationary contact instead of the housing. In this embodiment, the housing comprises an aperture, which is sized for receiving, by a substantially tight fitting, the thicker stationary contact of the two stationary contacts. The thinner stationary contact may comprise one or more projections, whose length corresponds to the thickness difference of the two stationary contacts, that is may be 5 mm, for instance.
In a further embodiment, the aperture comprises recesses, and both the stationary contacts comprise projections. The difference between the length of the projections correspond to the thickness difference of the stationary contacts.
The indications CLOSED/OPEN can be provided on the actuator. The “open” indication is in the actuator closer to the first stationary contact 110, whereby this indication is shown in the first window 104. The “closed” indication is closer to the second stationary contact 112, whereby this indication is shown in the second window 106.
It will be apparent to a person skilled in the art that, as the technology advances, the inventive concepts disclosed herein can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.
Thus, it will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.
Number | Date | Country | Kind |
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12171421 | Jun 2012 | EP | regional |
Number | Name | Date | Kind |
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2811618 | Cole et al. | Oct 1957 | A |
2956135 | Feil | Oct 1960 | A |
4796154 | Morris et al. | Jan 1989 | A |
5477016 | Baginski et al. | Dec 1995 | A |
Number | Date | Country |
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101 15 427 | Feb 2002 | DE |
1 703 533 | Sep 2006 | EP |
Entry |
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European Search Report issued on Nov. 29, 2012. |
Number | Date | Country | |
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20130327618 A1 | Dec 2013 | US |