This application is a national stage application (under 35 U.S.C. §371) of PCT/JP2006/062005 filed May 3, 2006, which claims benefit of Italian application BG2005A000024 filed May 13, 2005, disclosure of which is incorporated herein by reference.
The present invention relates to a switch, in particular a circuit breaker or a disconnector, that can be installed according to different operating configurations and that is to be used preferably in low-voltage systems.
It is known that automatic switches and disconnectors, for reasons of brevity hereinafter referred to as switches, comprise one or more electrical poles, associated to each of which are at least one fixed contact and at least one mobile contact which can be coupled to/uncoupled from one another.
Automatic switches of the known art also comprise control means that enable movement of the mobile contacts, so bringing about their coupling to or uncoupling from the corresponding fixed contacts.
The action of said control means occurs traditionally on a main shaft that is operatively connected to the mobile contacts so that, following upon its rotation, the mobile contacts are moved from a first operating position to a second operating position, which are characteristic of an open and closed configuration, respectively, of the switch.
In the case of switches for low currents, indicatively of up to 800 A, there exist solutions that lead the main shaft to coincide with the mobile contacts, giving rise to a rotating mobile element capable of guaranteeing insulation between the phases and of course correct transmission of the movements and of the forces involved. The mobile element is usually supported by structural parts of the box for containing the switch, which, together with the mobile element itself, basically form bearing areas.
As the currents involved increase, an increasing performance of mechanical tightness are required of the mobile element, given the same dielectric characteristics, which, in any case, must be preserved and guaranteed.
From the practical standpoint, the requirement of better mechanical characteristics results in an increase in the radial dimensions of the mobile element, with a consequent increase in the friction that is created in said bearing areas. This of course adversely affects the performance of the apparatus and tends to reduce the duration of the switch and of its parts, with progressive degradation of the overall mechanical efficiency.
To overcome the above drawback in arrangements also for high values of currents and breaking capacities, metal reinforcement shafts that pass through the mobile element have also been used. These, however, may interfere with the characteristics of electrical insulation between the poles and are certainly far from advantageous from the functional standpoint. In practice, these aspects for the moment limit the use of the mobile element to switches for low currents and low breaking capacities.
The increase in the radial dimensions of the mobile element, i.e. the increase in the weights involved may jeopardize correct installation of switches for high currents and high breaking capacities at different angles from the design one. This basically means that, in the state of the art, a switch for high currents or high breaking capacities designed to have the axis of the mobile element horizontal, cannot be installed according to different configurations, i.e. according to ones that bring said axis to be in a position different from the design one. Installations according to different angles jeopardize, in fact, the functionality of the switch since the weight of the mobile element may cause friction and bending that alter the normal conditions of coupling between the parts and of operation of the switch itself.
There consequently exists the need to extend the use of the mobile element also to those switches designed to operate with higher currents and breaking capacities in order to obtain greater flexibility of installation in the presence, for instance, of wiring systems or switchboards with busbars having a horizontal development.
On the basis of these considerations, the main task of what forms the subject of the present invention is to provide a switch that will enable the limits and drawbacks referred to above to be overcome.
In the framework of this task, a purpose of the present invention is to provide a switch that has a compact structure, which can be easily assembled and is made up of a limited number of components.
Another task of what forms the subject of the present invention is to provide a switch in which the friction between the different parts making up the switch will be extremely limited in any configuration of installation and will be compatible with a long service life and high levels of performance.
A further purpose of the present invention is to provide a switch that is functionally flexible, i.e. that can be installed in any operating configuration.
Not the least important purpose of what forms the subject of the present invention is to provide a switch that will present a high reliability, will be relatively easy to make, and offer competitive costs.
This task, as well as the above and other purposes that will emerge more clearly from what follows, are achieved through a single-pole or multi-pole switch for low-voltage wiring systems, comprising:
an outer casing containing for each pole at least one fixed contact and at least one mobile contact, which can be coupled to/uncoupled from one another;
a mobile element, defined by a shaped body comprising at least one seat for each pole of said switch, said seat being designed to house at least one mobile contact of a corresponding pole; and
an energy-accumulation control mechanism, operatively connected to said mobile element to enable its movement.
The switch according to the invention is characterized in that it comprises means of axial support, operatively connected to said mobile element.
The means of axial support are used for countering the gravitational thrusts on the mobile element generated when the latter is installed with the axis of rotation inclined with respect to a horizontal plane. The use of said means enables, in fact, limitation of the friction between the different parts that come into contact, thus guaranteeing proper functionality of the switch in any operating configuration.
Further characteristics and advantages of the invention will emerge more clearly from the description of preferred but non-exclusive embodiments of the switch according to the invention, illustrated by way of example in the attached plate of drawings, wherein:
With reference to the above figures, the switch according to the invention comprises an outer casing 2 containing one or more electrical poles, each defined by at least one fixed contact 10 that couples to/uncouples from at least one mobile contact 20. The outer casing 2 also houses a mobile element 50 made up of a shaped body made of insulating material, preferably a thermosetting resin, which comprises at least one seat 25 for each pole of the switch 1. Operatively connected to the mobile element 50 is a control mechanism 60 that enables movement thereof about a pre-set axis of rotation 100. The control mechanism 60 used is preferably of the energy-accumulation type normally employed in applications that envisage high values of current and/or breaking capacity.
The switch 1 according to the invention is characterized in that it comprises means of axial support that are operatively connected to said mobile element 50 in order to counteract the gravitational thrusts that are generated along its axis of rotation 100. These gravitational thrusts arise when said axis of rotation 100 is inclined with respect to a substantially horizontal plane. As hereinafter illustrated in detail, the presence of these supporting means enables limitation of any bending or friction that is generated on account of these gravitational thrusts, consequently increasing the number of the possible operating configurations of the switch 1.
With reference to
The structure of the casing 2 can be advantageously completed by a protective mask 5 that is applied to the lid 4 and, if necessary, can be easily removed by an operator to enable access to the internal parts of the switch 1.
In the case of use of outer casings of a metal type, as occurs normally in devices of an open type (ACBs—air circuit breakers), insulating elements will be set between the fixed contacts and the casing itself, as in the known art.
With reference once again to
In a preferred embodiment thereof, the seats 25 are defined basically by a front wall 26, a rear wall 27, substantially opposite to the front one 26, and by a first side wall 28 and a second side wall 29 substantially opposite to one another. These walls are mutually arranged in such a way as to generate at least one first opening and one second opening, from which there come out, respectively the corresponding mobile contact 20 and means of electrical junction 47 (see
The mobile element 50 comprises circular connecting parts 55a and 55b, located between two adjacent seats 25. In the solution illustrated in
Each of these connecting parts 55a and 55b comprises at least one radial recess, the function of which will be illustrated hereinafter. More precisely, the mobile element 50 illustrated in
In a preferred embodiment thereof, illustrated once again in
The axial supporting arms 80 and 81 are preferably constrained to the control mechanism 60 on the outer side of each side 71 and 72 through the use of removable fixing means 73, for instance screws or alternatively rivets. In a further solution, the supporting arms 80 and 81 could also be made of a single body with the sides 71 and 72, and hence without the use of fixing means.
It is evident that said connection renders the mobile element 50 substantially suspended in cantilever fashion with respect to the casing 2, and for said purpose the “three-lobed” shape of the supporting arms 80 and 81 is particularly advantageous in so far as it enables a greater resistance to bending and thus a more stable positioning of the mobile element itself. The supporting arms 80 and 81 provide the centre of rotation for the mobile element 50 through a hinge connection. The latter is provided within said radial recesses 51 and 52, which are pre-arranged in the connecting parts 55a and 55b of the mobile element 50. With reference, in particular, to
With reference once again to
With reference in particular to
An initial step envisages connection of the two supporting arms 80 and 81 in the radial recesses 51 and 52 and installation of the mobile element 50 through placing of the mobile contacts 20 in the seats 25. The mobile contacts 20 are in this step preferably already connected to the corresponding electrodes 22 through the aforementioned electrical-junction means 21. Next, the mobile element 50 is placed within the outer casing 2 generated by the coupling between the bottom 3 and the lid 4 and then connected to the control mechanism 60. In particular, the connection rods 91 and 92 of the kinematic means are fixed to the mobile element 50 in a position corresponding to the hollow sectors 57 thereof and through the use of the transverse pin 131. The supporting arms 80 and 81 are then fixed to the sides 71 and 72 of the structure 70 of the control 60 via the removable fixing means 73 in a position corresponding to the retention ends 86 and 86a provided on the arms themselves. The control 60 is then located in the correct operating position by means of the use of the axial tie-rods 62 that connect it stably to the bottom 3.
The sides 71 and 72 of the structure of the control 60 are shaped in such a way as to mate with the rear wall of the lid, which functions in practice as spacer between the control itself and the bottom. In this way also the mobile element 50 suspended from the control 60 is placed in the correct operating position.
The presence of the lid made of insulating material contributes also to improving the insulation of the control with respect to the electrical parts.
With reference to
The adaptation plates 151 and 152 may also have the supplementary purpose of increasing the rigidity of the mobile part 150, so limiting any deformation of the walls of the casing 2, above all in the cases where the switch 1 is installed according to a configuration different from the horizontal one.
Each of these adaptation plates 151 and 152 comprises a first flap 155 and a second flap 156 bent preferably into an L shape or into a U shape in order to slide in shaped guides 210, made on the fixed part 200 of the withdrawable switch 140. The adaptation plates 151 and 152 hence have the function of adapting the switch 1 to the withdrawable configuration.
As mentioned above, the fixed part 200 comprises driving means 300, which, in the arrangement illustrated, are constituted by a transverse shaft 305, at the end of which shaped volutes 306 are connected. The latter have a central groove 307, which intercepts hooks 159 extending from the adaptation plates 151 and 152.
The technical solutions adopted for the switch according to the invention thus enable the pre-set tasks and purposes to be fully achieved. The switch has a compact internal structure, which can be easily assembled and is made up of a limited number of components. The use of means of axial support enables installation of the switch in any operating configuration in so far as the deformation of the parts and the phenomena of friction are extremely limited.
The switch thus conceived may undergo numerous modifications and variations, all of which fall within the scope of the inventive idea; moreover all of the items may be constituted by other technically equivalent ones.
In practice, the materials used, as well as the contingent dimensions and shapes, may be any whatsoever according to the requirements and the state of the art.
Number | Date | Country | Kind |
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BG2005A0024 | May 2005 | IT | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2006/062005 | 5/3/2006 | WO | 00 | 11/13/2007 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2006/120142 | 11/16/2006 | WO | A |
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2 006 527 | May 1979 | GB |
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Number | Date | Country | |
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20080210532 A1 | Sep 2008 | US |