Abstract:
An electrical switch includes a gas-insulated tube, a contact system in the tube having fixed and movable contacts, a contact operating element passed out of the tube and movable along an actuation direction for opening and closing the system, and a contact pressure spring movable along the direction, connected to the operating element and an external drive element and disposed in a stationary guide part. The guide part guides the operating element. If the drive element shifts along the direction toward the fixed contact, the spring, operating element and movable contact move toward the fixed contact, closing the system and compressing the spring providing contact pressure force. The spring is in a housing connected to the operating element and movable relative to the guide part. A guide element is attached outside the housing, bears against the guide part, guides the housing and guides the operating element along the direction.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to an electrical switch having a gas-insulated tube, a contact system disposed in the tube and including a fixed contact and a moving contact, a moving contact operating element mechanically and electrically connected to the moving contact, routed out of the tube through an opening in the tube, and being movable along an operating direction for opening and closing the contact system, and a contact-pressure spring to be moved along the operating direction and being connected to the moving contact operating element and to an external drive element, and being disposed in a stationary guide part of the switch guiding the moving contact operating element. In the event of the external drive element moving along the operating direction in the direction of the fixed contact, the contact-pressure spring, the moving contact operating element and the moving contact move in the direction of the fixed contact, the contact system is closed and the contact-pressure spring is compressed with the provision of a contact-pressure force. 
     An electrical switch of this kind is known from European laid-open specification EP 2 270 827 A1. Said switch has a gas-insulated tube and a contact system which is arranged in the tube and comprises a fixed contact and a moving contact. Also provided is a moving contact operating element which is mechanically and electrically connected to the moving contact, is routed out of the tube through an opening in said tube, and can be moved along an operating direction for the purpose of opening and closing the contact system. The switch further comprises a contact-pressure spring which can be moved along the operating direction and is connected to the moving contact operating element and also to an external drive element, and is arranged in a stationary guide part of the switch, which guide part guides the moving contact operating element. In the event of the external drive element moving along the operating direction in the direction of the fixed contact, the contact-pressure spring, the moving contact operating element and also the moving contact move in the direction of the fixed contact, the contact system is closed and the contact-pressure spring is compressed with the provision of a contact-pressure force. 
     The problem of ensuring that the moving contact operating element which is routed out of the tube is guided to a sufficient extent is encountered in electrical switches with large and/or long gas-insulated tubes. The object of the invention is accordingly to specify a switch in which the problem of satisfactory guiding of the moving contact operating element is achieved in a structurally simple manner and at low cost. 
     BRIEF SUMMARY OF THE INVENTION 
     According to the invention, this object is achieved by a switch having the features recited below. Advantageous refinements of the switch according to the invention are specified in the dependent claims. 
     Accordingly, the invention makes provision for the contact-pressure spring to be arranged in a spring housing which is rigidly connected to the moving contact operating element and can be moved relative to the stationary guide part, and for at least one guide element to be fixedly attached to the outside of the spring housing, said guide element bearing against the stationary guide part and guiding the spring housing and also guiding the moving contact operating element along the operating direction. 
     A significant advantage of the switch according to the invention can be seen in that the spring housing has a dual function: it firstly serves to hold the contact-pressure spring, and secondly serves to guide the moving contact operating element. Guiding of the contact operating element can be improved without a great deal of expenditure and in a structurally simple manner by the incorporation of the spring housing. 
     In order to guide the contact operating element in the region of the spring housing particularly effectively, it is considered to be advantageous when two guide elements—spaced apart as seen along the operating direction—are attached to the spring housing and bear against the guide part. 
     In respect of the design of the spring housing, it is considered to be advantageous when said spring housing has a pot-like housing part and a cover part. When the spring housing is designed in this way, it is particularly advantageous when at least one of the guide elements is attached to or integrally formed on the pot-like housing part, and/or at least one of the guide elements is attached to or integrally formed on the cover part. 
     The external drive element can project, for example, into the spring housing, in particular into the pot-like housing part, in order to interact with the contact-pressure spring. 
     In respect of guiding the contact operating element in an optimum manner, it is further considered to be advantageous when a further guide element, which guides the moving contact operating element, is arranged between the spring housing and the tube—as seen along the operating direction. 
     With respect to the arrangement of the further guide element, it is advantageous when a contact disk is attached to or integrally formed on the moving contact operating element between the spring housing and the tube, and the further guide element is attached radially to the outside of the contact disk. 
     The contact disk and the further guide element preferably fulfill a dual function, specifically a guiding function and also an electrically conductive function; accordingly, it is advantageous when the contact disk and the further guide element are electrically conductive and enable current flow from the moving contact operating element, through the contact disk and the further guide element, to the guide part—and vice versa. 
     With respect to the design of the guide part, it is considered to be advantageous when said guide part is hollow-cylindrical or has at least one hollow-cylindrical section. 
     The guide element or guide elements which is/are attached to the spring housing preferably bears/bear radially against an inner wall of the hollow-cylindrical guide part or of the hollow-cylindrical section of the guide part. 
     The guide element or guide elements which is/are attached to the outside of the spring housing is/are preferably formed by a guide ring. In a corresponding manner, it is also advantageous when the further guide element or the further guide elements, which is/are arranged in the region between the spring housing and the tube, is/are formed by guide rings. 
     In respect of also guiding the contact operating element in the region of the tube, it is considered to be advantageous when the tube has a bearing or a bearing is attached to the tube, said bearing guiding the moving contact operating element in the region of the exit point of the moving contact operating element out of the tube along the operating direction. 
     The gas-insulated tube may be, for example, a vacuum tube; in this case, the switch is preferably a vacuum circuit breaker. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The invention will be explained in greater detail below with reference to exemplary embodiments; in this respect: 
         FIG. 1  shows, by way of example, an exemplary embodiment of a switch according to the invention, in which a guide element for guiding a moving contact operating element is attached to a spring housing, 
         FIG. 2  shows, by way of example, a further exemplary embodiment of a switch according to the invention, in which a guide element is attached to a spring housing, 
         FIG. 3  shows, by way of example, an exemplary embodiment of a switch in which two guide elements are attached to the spring housing of the switch such that they are spaced apart—as seen along the operating direction of the switch—and a further guide element is attached physically between the spring housing and a tube of the switch, and 
         FIG. 4  shows, by way of example, an exemplary embodiment of a switch according to the invention having two guide elements in the region of the spring housing, but without a further guide element in the region between the spring housing and the tube. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     In the figures, the same reference symbols are always used for identical or comparable components for reasons of clarity. 
       FIG. 1  shows an electrical switch  10  which may be, for example, a vacuum circuit breaker. The switch  10  has a gas-insulated tube  20 , for example in the form of a vacuum tube, in which a contact system  30  comprising a fixed or rather stationary contact  31  and also a contact  32  which can move in relation to the fixed contact  31  is arranged. 
     A moving contact operating element  40  is provided in order to move the moving contact  32  along an operating direction P relative to the fixed contact  31 , said moving contact operating element being connected to the moving contact  32  and allowing the moving contact  32  to move along the operating direction P. In the exemplary embodiment, the moving contact  32  and the moving contact operating element  40  are formed by separate elements which are connected to one another; as an alternative, the moving contact  32  and the contact operating element  40  can also be of integral design, or rather can be formed by a single component. 
     The moving contact operating element  40  extends through an opening  21  in the gas-insulated tube  20 , out of said opening, into a stationary guide part  50 . In the exemplary embodiment according to  FIG. 1 , the stationary guide part  50  is formed by a hollow-cylindrical body, or rather by a tube. 
     As shown in  FIG. 1 , the moving contact operating element  40  is connected to a spring housing  60  which can be of integral or multipartite design. In the exemplary embodiment according to  FIG. 1 , the spring housing  60  is of two-part design and is formed by a pot-like housing part  70  and also a cover part  80  which is located beneath the pot-like housing part  70  in the illustration according to  FIG. 1 . The cover part  80  is provided with an opening  81  through which an external drive element  90  projects into the interior of the spring housing  60 . 
     The external drive element  90  is connected to a spring end  101  of a contact-pressure spring  100  which is located within the spring housing  60  and of which that spring end  102  which is averted from the external drive element  90  is supported on the pot base of the pot-like housing part  70 . 
     The external drive element  90  can be used to move the moving contact operating element  40 , and also the contact  32  which moves in association with it, along the operating direction P, so that the contact system  30  can be opened or closed. In this case, the contact pressure spring  100  ensures that, when the contact system  30  is closed, there is a sufficient contact-pressure force between the fixed contact  31  and the moving contact  32 ; furthermore, the contact-pressure spring  100  ensures that, when the contact system  30  is opened, a so-called separating shock is generated, this being used to release or break any possible welding of the contact system  30 . 
     Moreover, a switching rod, not illustrated in the figures, can be connected to the external drive element  90 , for example by means of a rotary joint, it being possible for the drive element  90  to be moved by said switching rod in order to switch over the switch  10 . 
     As shown in  FIG. 1 , a flange section  71  is integrally formed on the pot-like housing part  70 , said flange section extending radially outward in the direction of the inner wall  51  of the guide part  50 . A guide element  110  in the form of a guide ring is provided between the flange section  71  and the inner wall  51  of the guide part  50 ; the guide element  110  is situated in a radially outer ring-like guide groove, or rather annular groove  71   a  of the flange section  71  and, in the case of a movement of the spring housing  60  along the operating direction P relative to the stationary guide part  50 , will be moved with said flange section. The function of the guide element  110  is to ensure that the moving contact operating element  40  is guided and therefore that the moving contact  32  is guided during the movement along the operating direction P. 
     In order to yet further improve guiding of the moving contact operating element  40 , a further guide element  200  is provided in the exemplary embodiment according to  FIG. 1 , it being possible for said guide element to likewise be a guide ring. The further guide element  200  is situated radially on the outside in an annular groove  210   a  of the contact disk  210  which is either integrally formed on the moving contact operating element  40  or is attached radially to the outside of the moving contact operating element  40 . Therefore, the further guide element  200  ensures, together with the contact disk  210 , further guiding of the contact operating element  40  during the movement along the operating direction P within the guide part  50 . 
     In addition to the described guiding function, the further guide element  200  and the contact disk  210  can have an electrical function if they—as is considered to be advantageous—are designed electrically with a low impedance and/or so as to conduct current. If, specifically, the further guide element  200  and the contact disk  210  are electrically conductive, a current flow I can take place along the double-headed arrow, which is identified by reference symbol I, between the guide part  50  and the contact operating element  40 , as a result of which a current flow through the spring housing  60  is advantageously avoided. In other words, the current flowing through the contact system  30  will therefore pass by the spring housing  60  and the contact-pressure spring  100  located in said spring housing via the further guide element  200  and the contact disk  210 . 
     In the exemplary embodiment according to  FIG. 1 , guiding of the contact operating element  40  within the guide part  50  is ensured by the guide element  110  and the further guide element  200 . In order to furthermore also ensure particularly good guiding in the region of the opening  21  in the tube  20 , a bearing  300  is additionally provided in the region of the opening  21  in the exemplary embodiment according to  FIG. 1 . In other words, three guide elements are therefore provided in the exemplary embodiment according to  FIG. 1 , specifically the guide element  110  in the region of the spring housing  60 , the further guide element  200  in the region between the spring housing  60  and the opening  21 , and also the bearing  300  which is attached to the tube  20 , or rather is formed in said tube, in the region of the opening  21 . 
       FIG. 2  shows a further exemplary embodiment of a switch  10 , in which a guide element  110  is attached to a two-part spring housing  60 . In contrast to the exemplary embodiment according to  FIG. 1 , in the exemplary embodiment according to  FIG. 2 , the guide element  110  is not attached to the pot-like housing part  70 , or rather to the flange section  71  of the pot-like housing  70 , but rather in the region of the cover part  80 . 
     In order to allow or to simplify attachment of the guide element  110  to the cover part  80 , said guide element is designed to be larger than the cover part  80  in the radial direction or perpendicular to the operating direction P according to  FIG. 1 . The design of the cover part  80  shown in  FIG. 2  allows radially outer positioning of the guide element  110  between the cover part  80 , or rather the spring housing  60 , and the guide part  50 , so that the guide element  110  can ensure guiding of the contact operating element  40 , as has already been described in connection with  FIG. 1 . 
     The switch  10  according to  FIG. 2  is also equipped with a further guide element  200  in the region between the spring housing  60  and the opening  21  in the vacuum tube  20  and also with a bearing  300  in the region of the opening  21 ; in respect of the function of the further guide element  200  and of the bearing  300 , reference may be made to the above explanations in connection with  FIG. 1  in respect of guiding the contact operating element  40 . The above explanations in respect of the current-carrying properties of the guide element  200  and of the contact disk  210  also correspondingly apply in the exemplary embodiment according to  FIG. 2  since the guide element  200  and the contact disk  210  are also preferably electrically conductive in the exemplary embodiment according to  FIG. 2 . 
       FIG. 3  shows an exemplary embodiment of a switch  10 , in which not only one guide element  110 , but rather two guide elements  110  and  110   a  are arranged on a two-part spring housing  60 . The two guide elements  110  and  110   a  are arranged spaced apart from one another as seen along the operating direction P, so that the two guide elements  110  and  110   a  alone can already guide the contact operating element  40  for a movement along the movement direction P themselves. 
     As shown in  FIG. 3 , the guide element  110  is preferably attached to a flange section  71  of the pot-like housing part  70 , as has already been explained in connection with  FIG. 1 ; and the guide element  110   a  is attached in the region of the cover part  80 , as has already been explained above in connection with  FIG. 2 . 
     In the exemplary embodiment according to  FIG. 3 , the contact operating element  40  is guided along the operating direction P, that is to say through the two guide elements  110  and  110   a  which are attached to the spring housing  60 , the further guide element  200  which is attached to the electrically conductive contact disk  210 , and also the bearing  300  in the region of the opening  21  in the tube  20 . 
       FIG. 4  shows an exemplary embodiment of a switch  10 , in which two guide elements  110  and  110   a  are attached to the spring housing  60 , as is also the case in the exemplary embodiment according to  FIG. 3 . In contrast to the exemplary embodiment according to  FIG. 3 , the exemplary embodiment according to  FIG. 4  does not have the further guide element  200  or the contact disk  210 , so that guiding of the contact operating element  40  is based solely on the two guide elements  110  and  110   a  and also the bearing  300 . 
     Since the further guide element  200 , or rather the contact disk  210  (cf.  FIGS. 1 to 3 ), is omitted, it is not possible for the current flowing through the contact system  30  to pass by the spring housing  60 , but rather the current has to flow through the pot-like housing part  70 , the flange section  71  and also the guide element  110 , which is located on the flange section  71 , to the guide part  50 . In the refinement according to  FIG. 4 , it is therefore advantageous to design the pot-like housing part  70  and also the flange section  71  to be very solid, or rather have a very thick wall, in order to ensure an electrical resistance between the guide part  50  and the contact operating element  40  which is as low as possible. 
     Although the invention has been described and illustrated more specifically in detail by preferred exemplary embodiments, the invention is not restricted by the disclosed examples and other variants can be derived from said examples by a person skilled in the art, without departing from the scope of protection of the invention.