EP3625813B1 - Contact press-on assembly - Google Patents

Description

The invention relates to a contact pressure arrangement for a switching contact piece of an electrical switching device, having a first stop and a second stop, between which a spring element extends, the first stop being movable relative to the second stop, the second stop forming an abutment for the first stop and at least one of the stops provides a pivot bearing for the spring element.

Such a contact pressure arrangement is, for example, from the utility model CN 2386525 Y known. The contact pressure arrangement there is provided for a switching contact piece of an electrical switching device. A spring element extends between a first stop and a second stop. The first stop can be moved relative to the second stop, with the second stop forming an abutment for the first stop. Provision is also made to provide a stop with a rotary bearing.

The known contact pressure arrangement uses a complex axial ball bearing as a pivot bearing. On the one hand, the known construction enables elements of the contact pressure arrangement to rotate smoothly relative to one another. On the other hand, however, this ease of movement is caused by increased masses and an increased installation space compared to conventional contact pressing arrangements.

The disclosure document DE 10 2013 221 910 A1 an electrical switch can be removed. The electrical switch has a fixed and a movable contact. To generate a contact pressure force, a contact pressure spring is described, which is arranged within a spring housing, the spring on a pot bottom of the pot-shaped Spring housing and a cover part of the spring housing is supported. The European patent application EP 3 089 188 A1 a switching device with a housing can be removed. A movable and a fixed contact are arranged in the housing. An associated drive unit has a spring which is arranged between a drive-side receptacle and a contact-side receptacle. From the patent U.S. 8,30 9,872 B2 discloses an insulating drive rod having a contact pressing arrangement. A spring element extends between a first stop and a second stop. A spring plate is arranged between the spring element and the respective stop.

It is therefore an object of the invention to specify a contact pressure arrangement which enables sufficient rotational mobility on a contact pressure arrangement with a reduction in mass and sufficient mechanical stability in a compact installation space.

According to the invention, the object is achieved with a contact pressure arrangement of the type mentioned at the outset in that the pivot bearing can be moved together with the first stop and the abutment has a damping element for the first stop.

An electrical switching device has a switching contact piece which can be moved relative to another switching contact piece. A current path can be established or disconnected by a relative movement of the switching contact pieces to one another. In order to enable sufficient contacting of the switching contact pieces, a contact pressure arrangement is used, which secures the switching contact pieces in a position relative to one another. The relative position to be secured can be a switched-on state of the electrical switching device. When switched on, the switching contact pieces touch each other and a current path is closed via the switching contact pieces. The contact pressing arrangement causes a force to act on the switching contact pieces that can be moved relative to one another, so that the position of the switching contact pieces relative to one another is secured. The contact pressing arrangement can preferably brace the switching contact pieces against one another and move them towards one another or press them against one another. For this purpose, the contact pressing arrangement is, for example, part of a kinematic chain which enables the transmission of a movement for generating a relative movement of the switching contact pieces of the switching device to one another. A spring element of the contact pressing arrangement is arranged between a first and a second stop, the stops being movable relative to one another. A relative movement of the stops can be used to tension or apply force to the spring element, so that the energy thus introduced into the spring element is available to cause contact pressure on the switching contact pieces of the switching device, for example when the kinematic chain is at rest. The spring element is tensioned, for example, by the stops approaching or moving away from one another. By using the second stop to form an abutment for the first stop, a reference value is given to enable tensioning or relaxation of the spring element even if all the stops are movable. This makes it possible to use the contact pressure arrangement itself as a moving part (transmission element) of the kinematic chain. For example, the contact pressing arrangement of a transmission of a movement, z. B. serve a linear movement. In this case, due to the effectiveness of the spring element between the stops, the contact pressure arrangement can act as a so-called dead time element, which z. B. causes a delayed transmission of a movement within the kinematic chain due to an elastic deformability of the spring element. Depending on the design of the spring element, however, the spring element can also have such a rigidity that only when an overstroke occurs, ie after the switching contact pieces of the switching device have come into contact with one another, further movement within the kinematic chain is no longer transmitted to the switching contact pieces. This also protects the kinematic chain from damage. The contact pressing arrangement can advantageously be designed in such a way that the spring element acts only on one side. i.e. Particularly in the case of a translatory transmission of a movement by means of the contact pressure arrangement, an effective function of the spring element can occur during a movement in a first direction, with a direct transmission (rigid coupling) of the Movement can take place by means of the contact pressing arrangement.

Rotational forces can occur within the kinematic chain as a result of external forces (e.g. during a movement, assembly, etc.). This is disadvantageous since, for example, connecting elements such as bolts, cotter pins, etc., can shear off or be bent as a result. For example, screw connections can also be loosened over time by such torsional loads. By using a rotary bearing, such forces can be relieved in the contact pressure arrangement. The pivot bearing can thus serve as a freewheel, for example to protect the spring element from transverse forces introduced from the outside. As a result, the spring effect of the spring element can be retained. In addition, other forces can also be absorbed in the contact pressing arrangement, so that not only the spring element but also, for example, other elements such as screw connections, bolts, splints of the kinematic chain are protected.

Equipping a stop with the pivot bearing makes it possible to freewheel or release forces directly in the area of the spring element. through a common By moving the stop and the rotary bearing, rotary movements on the spring element can be decoupled, regardless of the loading state of the spring element. By moving the first stop together with the pivot bearing, the use of multiple pivot bearings can be dispensed with. The installation space of a contact pressure arrangement according to the invention is thus reduced. Furthermore, the mass of the contact pressure arrangement and thus the moving mass in the kinematic chain is reduced by dispensing with a further rotary bearing. Due to the movement of the pivot bearing together with the first stop, a rotary movement can be intercepted directly on the spring element or reduced in the pivot bearing. The spring element is thus protected from external forces. The pivot bearing can advantageously be integrated into the first stop, so that no additional installation space is required to accommodate the pivot bearing on the first stop. The pivot bearing can thus move, in particular relative to the second stop, it being possible for the first stop to have the pivot bearing. Furthermore, the spring element can serve to secure the pivot bearing.

It can advantageously also be provided that the first stop is guided by the second stop.

The second stop can serve to guide the first stop. This makes it possible to use the second stop as a reference base for a relative movement of the first stop and for a relative movement of the rotary bearing. For example, the second stop in the manner of a housing, z. B. as a hollow cylindrical housing, which in particular surrounds the spring element. As a result, the second stop can act as a spring housing. The first stop can be supported on the second stop or on the housing and can be guided by the second stop. This enables a defined linear relative movement between the first and second stops. Canting and tipping is avoided. For example, the first stop dive into the second stop. Advantageously, it can be provided that the second stop is designed in the manner of a cylinder and the first stop in the manner of a piston, so that the first stop can dip into the second stop. The spring element can be tensioned or released by a relative movement of the first and second stop.

It can be provided that the stops are axially movable relative to each other.

An axial mobility of the stops enables a linear movement in a simple manner in order to cause a tensioning or relaxation of a spring element. Advantageously, the movement path of the relative movement of the first and second stops can be aligned coaxially, in particular congruently, with a movement which the contact pressing arrangement performs as part of an integration into a kinematic chain. This makes it possible in a simple manner to use the contact pressure arrangement on the one hand to transmit a movement and on the other hand to use the contact pressure arrangement to press a switching contact piece against a mating contact of an electrical switching device. At least one of the stops can be formed and aligned coaxially to the movement axis.

Advantageously, it can also be provided that the first stop has a rotatable disk, which is supported on the second stop.

A rotatable disk offers the possibility of providing a relative movement of the rotatable disk to other assemblies of the first stop, for example with respect to a support element. A rotatable disk can, for example, be designed as a complete circular disk. However, it can also be provided that only a ring shape is used to rotate the disk to train. In addition, the disc can also be designed only in sections, so that, for example, only sectors of a circular disc are used. Advantageously, the rotatable disc can be supported on the second stop with body sections on the casing side. A sliding arrangement can advantageously be arranged there in order to reduce the frictional resistance between the rotatable disk and the second stop. This can be done, for example, by applying material in a bush-like manner to the rotatable disk. For example, polytetrafluoroethylene strips or copper bushings can serve as sliding elements. Force can be introduced from the spring element on the front side of the pane, so that the axis of movement of the first stop relative to the second stop and the introduction of force from the spring element are aligned essentially parallel to one another. The spring element can preferably act directly or indirectly on the end face of the rotatable disk or be attached to the rotatable disk.

A further advantageous embodiment can provide that the rotatable disk is connected to a support element of the first stop via a loose fit.

A support element of the first stop serves to position the rotatable disk. The rotatable disc can be placed on the support element or attached to the support element, so that a rotary movement of the rotatable disc relative to the support element is made possible. In this case, to enable a rotational movement, the support element and the rotatable disk can be connected to one another via a clearance fit. The loose fit can be secured by the force of the spring element, so that a removal or loosening of the rotatable disk and the support element is prevented by the spring element. The spring element serves to secure the loose fit. The clearance can cause an axial and radial guidance of the rotatable disk.

A further advantageous embodiment can provide that the first stop has a guide mandrel which is at least partially encompassed by the spring element.

The use of a guide mandrel on the first stop makes it possible to enable the spring element to be steered or guided beyond the function of the stop. The spring element can, for example, at least partially encompass the guide mandrel, so that the spring element is secured on the guide mandrel and thus on the first stop. This makes it more difficult for the spring element to loosen or tilt. Furthermore, the guide mandrel can ensure that the spring element rests securely on the rotatable disk.

The guide mandrel can be formed, for example, at least from parts of the rotatable disk. In particular when using a rotatable disk which has an annular shape, the central area of the disk can be used to form the guide mandrel. The guide mandrel can, for. B. be formed from parts of the rotatable disk. However, the guide mandrel can also be formed at least partially from the support element.

Advantageously, it can also be provided that the guide mandrel is guided by the second stop.

Advantageously, the guide mandrel directs and guides the spring element. The position of the guide pin is secured by guiding the guide pin on the second stop. As a result, the relative movement of the first stop and the second stop with respect to one another is also stabilized via the guide mandrel. Furthermore, the spring element can be mounted or guided in an improved manner so that unwanted buckling or buckling of the spring element is made more difficult.

Depending on the design of the guide mandrel, the first stop can be guided on the second stop by the support element and/or by the rotatable disk and/or on the guide mandrel.

A further advantageous embodiment can provide that the first stop and the second stop are guided in a telescoping manner.

The first stop and the second stop can be moved relative to one another. This movement can preferably be a linear relative movement. The spring element extends between the stops. By using telescoping stops, the relative movement of the first and second stops can be transmitted in an improved form. By telescoping, i. H. a tilting of the stops in relation to one another is additionally prevented by the first and second stops collapsing into one another. In order to additionally improve the guidance, it can be provided that the first and the second stop are guided in a telescoping manner relative to one another at a number of points. For example, the second stop can surround the first stop in the manner of a housing, with the spring element being arranged inside the second stop. The spring element, in turn, can be covered by the first or second stop on the inner and outer casing side and finally guided.

Provision can advantageously be made for the spring element to have a compression stage.

A spring element with a compression stage can be constructed in a mechanically simple manner. For example, the spring element can be designed in the manner of a helical spring, with a force acting on the spring element when the first stop and the second stop approach one another and compression of the spring element causes charging or energy to be introduced into the spring element.

Furthermore, it is provided that the abutment has a damping element for the first stop.

Movement of the first stop is limited by an abutment. The abutment can preferably be made available by the second stop, with the use of a damping element on the abutment dampening a hard coupling of forces or impulses from the first stop into the second stop. The damping element can be designed as an energy absorption element. For example, the damping element can be designed as a cup spring. Disc springs have a small stroke with high spring rates. The abutment makes it possible to apply a prestress to the spring element. In this way, in particular, the loose fit can be secured.

A further object of the invention is to specify an electrical switching device which has a first and a second switching contact piece, the switching contact pieces being movable relative to one another. The electrical contacting of the switching contact pieces should be mechanically and electrically stable. It is therefore the object of the invention to specify a shifting device which can carry out reliable shifting operations. According to the invention, the object is achieved in an electrical switching device with a first switching contact piece and a second switching contact piece, which can be moved relative to one another, in that a kinematic chain, which is used to move the switching contact pieces relative to one another, has a contact pressure arrangement according to one of the above statements.

An electrical switching device is a device by means of which a current path can be interrupted or established. For this purpose, relatively movable switching contact pieces are used, wherein at least one of the switching contact pieces is coupled to a kinematic chain to a To be able to cause relative movement between the switching contacts. A relative movement is generated via the kinematic chain, it being possible for the contact pressing arrangement to be designed as part of the kinematic chain. The contact pressure arrangement can thus on the one hand achieve sufficient contact pressure force of the switching contact pieces relative to one another, and on the other hand the contact pressure arrangement with a spring element arranged therein protects against mechanical overload, for example as a result of the switching contact pieces colliding bluntly. The switching contact pieces can, for example, be arranged opposite one another at the ends and butt-butt against one another with their end faces in order to make contact. The contact pressure arrangement secures the abutting switching contact pieces in a switched-on position of the electrical switching device.

Between the switching contact pieces of the electrical switching device there extends a contact gap which, depending on the switching state of the electrical switching device, has a contact resistance which tends towards infinity or tends towards zero.

A contact gap can advantageously be arranged between the switching contact pieces within a vacuum interrupter.

By using a vacuum, the presence of free charge carriers, which would allow an electric current to be transmitted via the contact gap in the switched-off state, is ruled out. The interior of the vacuum interrupter is hermetically sealed from the environment of the vacuum interrupter. A relative movement of the switching contact pieces to one another is generally transmitted through a wall of the vacuum interrupter.

Figur 1

einen Schnitt durch ein elektrisches Schaltgerät im ausgeschalteten Zustand; die

Figur 2

einen Schnitt durch das elektrische Schaltgerät im eingeschalteten Zustand; die

Figur 3

einen Schnitt durch eine Kontaktanpressanordnung, wie aus den Figuren 1 und 2 bekannt, im Detail.

In the following, an exemplary embodiment of the invention is shown schematically in a drawing and described in more detail below. The

figure 1

a section through an electrical switching device in the off state; the

figure 2

a section through the electrical switching device when switched on; the

figure 3

a section through a contact pressing arrangement, as shown in FIGS figures 1 and 2 known in detail.

The figure 1 shows an electrical switching device which has a vacuum interrupter 1. The vacuum interrupter 1 has an electrically insulating main body. In the present case, the electrically insulating main body is designed as a hollow cylinder and is aligned rotationally symmetrically with respect to a main axis 2 . At the front, the main body of the vacuum interrupter 1 is sealed off in a fluid-tight manner by electrically conductive sealing caps, so that a vacuum is hermetically enclosed inside the vacuum interrupter 1 . The electrical switching device also has a first switching contact piece 3 and a second switching contact piece 4 . The two switching contact pieces 3, 4 are constructed in the same way. They each have a contact stem and a contacting area. The switching contact pieces 3, 4 are arranged opposite one another at the ends and are essentially aligned coaxially to the main axis 2, with the contacting regions of the switching contact pieces 3, 4 facing each other. The first switching contact piece 3 is aligned in a stationary manner relative to the vacuum interrupter 1 . The second switching contact piece 4 is aligned to be movable relative to the first switching contact piece 3 . Between the ends facing each other (contact areas) of the switching contact pieces 3, 4, a contact gap 5 is arranged. The contact stem of the first switching contact piece 3 is at a fixed angle in the associated end face Sealing cap of vacuum interrupter 1 inserted. The second switching contact piece 4 or its stem passes through the other electrically conductive sealing cap of the vacuum interrupter 1. A reversibly deformable, vacuum-tight bond between a front sealing cap and the second switching contact piece 4 is formed by means of a bellows 6. Correspondingly, the second switching contact piece 4 can be moved along the main axis 2 , it being possible to move relative to the vacuum interrupter 1 and relative to the first switching contact piece 3 . The first switching contact piece 3 is connected to a phase conductor 7 at a fixed angle, so that the vacuum interrupter 1 is mechanically supported on the phase conductor 7 via the first switching contact piece 3 . Furthermore, an electrically conductive connection is provided between the first switching contact piece 3 and the phase conductor 7 via the contacting with the phase conductor 7 . The second switching contact piece 4 is electrically conductively connected to a further phase conductor 8 via a suitable connection. A flexible electrically conductive connection between the second switching contact piece 4 and the additional phase conductor 8 is shown in the figure as an example. It can also be provided that other suitable contacts, such as sliding contacts, sliding contacts or the like, are used in order to electrically connect the movable second switching contact piece 4 to the other phase conductor 8 and in doing so not significantly impair the mobility of the second switching contact piece 4. Electrical contacting of the second switching contact piece 4 as well as the first switching contact piece 3 advantageously takes place outside of the vacuum interrupter 1 . An electrically conductive connection between the phase conductor 7 and the further phase conductor 8 can be produced or separated via the two switching contact pieces 3, 4.

In order to be able to bring about a movement of the second switching contact piece 4, a drive device 9 is provided. The drive device 9 can deliver a drive movement to to bring about a movement of the second switching contact piece 4 . A kinematic chain 10 is used in order to transmit the movement in a suitable form, if necessary to transform it or to influence it. The kinematic chain 10 extends from the drive device 9 to the second switching contact piece 4. For this purpose, the kinematic chain 10 has various transmission elements. On the one hand, a stationarily mounted two-armed deflection lever 11 is provided, which is connected to the drive device 10 with a first lever arm via a connecting rod 12 . The deflection lever 11 is coupled to a connecting rod 13 with a second lever arm. The push rod 13 has an electrically insulating section, so that the deflection lever 11 and the other elements of the kinematic chain 10 lying in the direction of the drive device 9 are electrically insulated from the second switching contact piece 4 . The push rod 13 has, for example, a tube which is made of electrically insulating material, for example glass fiber reinforced plastic.

The push rod 13 is connected to a contact pressure arrangement 14 by its end facing away from the deflection lever 11 . The contact pressure arrangement 14 is used to transmit a linear movement that can be coupled from the push rod 13 to the contact pressure arrangement 14 . The contact pressing arrangement 14 is in turn connected to the second switching contact piece 4 so that a movement coupled in by the connecting rod 13 can be transmitted to the second switching contact piece 4 via the contact pressing arrangement 14 . The contact pressing arrangement 14 has a first stop 15 and a second stop 16 . The first stop 15 is connected to the push rod 13 . A spring element 17 is arranged between the first stop 15 and the second stop 16 . The spring element 17 is used to transmit a movement which emanates from the first stop 15 . The first stop 15 is guided by the second stop 16 . The first stop 15 is in the manner of a piston within a cylinder-like opening of the second stop 16 out. The spring element 17 is guided under prestress between the two stops 15, 16, with the second stop 16 providing an abutment 18 for the first stop 15. The abutment 18 enables the spring element 17 to be prestressed between the two stops 15 , 16 . The first stop 15 can be moved relative to the second stop 16 , such a movement taking place under tension or relaxation of the spring element 17 . A more detailed structure of the contact pressure arrangement 14 is exemplified in FIG figure 3 shown.

During a switch-on process, a drive force is transmitted from the drive device 9 to the kinematic chain 10 . The connecting rod 12 controls the deflection lever 11 , whereupon this transfers a movement to the push rod 13 . Due to a rotatable coupling, overstrokes due to the rotary movements of the deflection lever on the connecting rod 12 or push rod 13 are compensated. During a switch-on movement, a movement is applied to the (preloaded) spring element 17 via the first stop 15 , as a result of which this moves the first stop 16 . The second switching contact piece 4 is connected at a fixed angle to the first stop 16 , so that a movement is also transmitted to the second switching contact piece 4 . The contacting area of the second switching contact piece 4 approaches the contacting area of the first switching contact piece 3 . The switching path 5 is reduced in its extension along the main axis 2 . Movement of the second switching contact piece 4 as well as the contact pressure arrangement 14 essentially takes place in the direction of the main axis 2. When the contacting areas of the first switching contact piece 3 and the second switching contact piece 4 come into contact, a current path between the phase conductor 7 and the further phase conductor 8 is closed. In order to secure the position of the switching contact pieces 3, 4, after the contact has been made and after an end of the relative movement of the switching contact pieces 3, 4 to one another, an overtravel is carried out by the drive device 9 causes. Due to the rigid striking of the second switching contact piece 4 against the first switching contact piece 3, the second stop 16 is prevented from moving any further. By driving the drive device 9 further, the first stop 15 is driven further. Due to the fixing of the second stop 16, the spring element 17 is tensioned. After the spring element 17 has been sufficiently tensioned, the drive device 9 is switched off, as a result of which the position of the push rod 13 is fixed. The push rod 13 thus continues to press the first stop 15 with the interposition of the tensioned spring element 17 against the second stop 16 and thus the two switching contact pieces 3, 4 are pressed against one another. In the switched-on state, the contact pressure arrangement 14 ensures the relative position of the two switching contact pieces 3, 4 with respect to one another.

The switched-on state of the electrical switching device is in the figure 2 shown. In comparison to figure 1 it can be seen that the first stop 15 has moved away from the abutment 18, with the spring element 17 experiencing tension.

During a switch-off operation (reversal of movement from the figure 2 to the figure 1 ) the sense of direction of the drive movement of the drive device 9 changes, ie via the connecting rod 12 and the deflection lever 11 the connecting rod 13 is moved in the opposite direction along the main axis 2 . As a result, the spring element 17 is initially relaxed until the first stop 15 comes to rest on the abutment 18 of the second stop 16 . The spring element 17 is now under prestress. When the first stop 15 strikes the abutment 18 of the second stop 16, a movement which is triggered by the push rod 13 is also transmitted directly to the second switch contact piece 4 via the contact pressure arrangement 14. The second switching contact piece 4 moves relative to the first switching contact piece 3, so that the switching distance 5 increases.

Based on figure 3 is a structure of the contact pressing arrangement 14, as shown in FIGS figures 1 and 2 known, described. The contact pressing arrangement 14 has the second stop 16 . The second stop 16 is designed in the manner of a cylinder, in which the first stop 16 is guided in an axially displaceable manner. A relative movement of the first and second stop 15, 16 takes place essentially along the main axis 2. In the present case, an abutment 18 for the first stop 15 is designed in such a way that an annular disk with the interposition of a plate spring 19 (damping element) forms a cylinder opening in the second stop 16 constricted. The elastic design of the abutment 18 dampens the impact of the first stop 15 against the abutment 18 . Alternatively, instead of using a disk spring 19, another consumption element can also be provided.

In order to be able to couple the first stop 15 to the connecting rod 13 , the first stop 15 is equipped with a support element 20 . On the one hand, the support element 20 protrudes into the interior of the second stop, and on the other hand, the support element 20 protrudes through the cylinder opening of the second stop 16 and out of the second stop 16 . The push rod 13 can be coupled directly or indirectly to the support element 20 via a rotary joint by means of a thread or a lug. The support element 20 is designed essentially in the form of a bolt, with the bolt axis extending essentially coaxially with the main axis 2 . The support element 20 is equipped with a collar 21 which extends radially around an outer surface of the bolt of the support element 20 . The position of the collar 21 is chosen in such a way that it is encompassed by the second stop 16 . Suitably, this collar 21 can be used to strike the abutment 18, so that a release of the first stop 15 from the second stop 16 driven by the spring element 17 is prevented.

The support element 20 has a rotatable disk 22 on the end face. The rotatable disk 22 is used for resting the spring element 17 on the first stop 15. The rotatable disk 22 is rotatably mounted on the support element 20 relative to the main axis 2. In the present case, the rotatable disk 22 is designed in such a way that it covers the end face of the collar 21, which faces the spring element 17, and also covers the collar 21 on the casing side. Together with the surface with which the collar 21 comes into contact with the abutment, an aligned termination of the disk 22 is provided, so that both the collar 21 and the rotatable disk 22 come into contact with the abutment 18 . On the shell side, the rotatable disc 22 is supported on the inside on a hollow cylinder recess of the second stop 16 and is guided in an axially movable manner. In order to provide improved guidance, a slide ring 23 is arranged on the circumference of the rotatable disk on the shell side. The rotatable disk 22 is used for the contact of the spring element 17 , which presses the rotatable disk 22 against the abutment 18 by means of a pre-compression relative to the second stop 16 . A loose fit is formed between the rotatable disk 22 and the support element 20 , as a result of which the rotatable disk 22 can be guided in a rotatable manner on the support element 20 in a cost-effective manner.

In order to ensure improved radial and axial guidance of the rotatable disk 22 on the support element 20 of the first stop 15, the rotatable disk 22 is equipped with a guide mandrel 24 centrally. The guide mandrel 24 extends centrally within the cylinder recess of the second stop 16. A part of the support element 20 also extends within the guide mandrel 24, as a result of which the guide mandrel 24 extends both through the rotatable disk 22 and through the support element 20 at least is formed in sections. The spring element 17 is located in an annular gap between the outer lateral surface of the guide mandrel 24 and the inner lateral surface of the cylindrical recess of the second stop 16. The spring element 17 is in the present case in the form of a helical spring, which is a so-called helical spring with pressure stage, i.e. a tension of the spring element 17 takes place with the windings approaching.

At its end remote from the abutment 18 of the first stop 15, the guide mandrel 24 is provided with a frontal recess into which the second stop 16 protrudes with a section. As a result, the first stop 15 and the second stop 16 are telescopically connected to one another, with a relative movement of the first stop 15 to the second stop 16 causing the stops 15, 16 to dip into one another. To improve the sliding connection between the first stop 15 and the second stop 16, a further sliding bush 25 is introduced into the recess of the guide mandrel 24 on the inner surface side. A threaded rod 26 is arranged on the second stop 16 coaxially with the alignment of the support element 20 of the first stop 15 , by means of which the contact pressure arrangement 14 is connected at a fixed angle to the second switching contact piece 4 via the second stop 16 .

During a switch-on process before contact is made between the two switching contact pieces 3, 4, the pre-compression of the spring element 17 is selected in such a way that the spring element 17 presses the first stop 15 against the abutment 18, with the second stop 16 being the basis for the abutment 18 due to the mounting of the abutment Relative movement of the first stop 15 forms. The spring element 17 ensures a rigid coupling of the two stops 15, 16 until contact is made between the two switching contact pieces 3, 4. Even in this state, rotary movements in the first stop 15 can be neutralized. With a galvanic contact of the two switching contact pieces 3, 4 and a movement that continues to occur within the kinematic chain 10, there is a deformation of the spring element 17 (tension of the spring element 17) due to a relative movement of the first stop 15 in relation to the second stop 16. The tensioned spring element 17 can now exert a contact pressure force between the two switching contact pieces 3, 4 effect. During a switching-off process, the sense of direction of the movement of the kinematic chain 10 is reversed. By the disc spring 19 this bumping is dampened. When the first stop 15 rests on the abutment 18 , a movement which is triggered by the drive device 9 and transmitted via the kinematic chain is now also transmitted to the second switching contact piece 4 . The second switch contact piece 4 is detached from the first switch contact piece 3 and removed.

Due to the many transmission elements in the course of the kinematic chain and the deflection or transformation of the movement, lateral forces can occur in the kinematic chain 10, which load the individual bearing points or deflection points. By using a first stop 15 with a rotary bearing, rotary movements that could continue to the second switching contact piece 4 can be neutralized in the contact pressure arrangement. The swivel joint in the first stop serves as a freewheel, so that rotary movements of the switching contact pieces 3, 4 are decoupled. In addition, the spring element 17 is protected from torsional loads that could change the spring behavior of the spring element 17 . The rotary bearing, which is arranged between the support element 20 and the rotatable disk 22 on the first stop 15, is moved together with the first stop 15 when it moves. As a result, there is a load regardless of a relative position of the stops 15, 16 to one another or the state of the kinematic chain or securing of the pivot bearing by the spring element 17 is ensured. Accordingly, undesired forces in the kinematic chain can be neutralized by means of a single movable pivot bearing. This prevents unwanted movement of the switching contact pieces 3, 4 and also keeps the contact pressure arrangement 14 free of such forces, with the forces in the contact pressure arrangement 14 itself being able to be neutralized.

Claims (11)

1. Contact press-on assembly (14) for a switching contact piece (3, 4) of an electrical switching unit, the contact press-on assembly (14) having a first stop (15) and a second stop (16), between which a spring element (17) extends, the first stop (15) being movable relative to the second stop (16), the second stop (16) forming an abutment (18) for the first stop (15) and at least one of the stops (15, 16) providing a rotary bearing (22) for the spring element (17), the rotary bearing being movable together with the first stop (15), characterized in that the abutment (18) has a damping element (19) for the first stop (15).
2. Contact press-on assembly (14) according to Claim 1, characterized in that
   the first stop (15) is guided by the second stop (16).
3. Contact press-on assembly (14) according to either of Claims 1 and 2,
   characterized in that
   the stops (15, 16) are movable axially in relation to one another.
4. Contact press-on assembly (14) according to one of Claims 1 to 3,
   characterized in that
   the first stop (15) has a rotationally movable disk (22), which is supported on the second stop (16).
5. Contact press-on assembly (14) according to Claim 4, characterized in that
   the rotationally movable disk (22) is connected to a carrying element (20) of the first stop (15) by way of a clearance fit.
6. Contact press-on assembly (14) according to one of Claims 1 to 5,
   characterized in that
   the first stop (15) has a guide pin (24), which is at least partially enclosed by the spring element (17).
7. Contact press-on assembly (14) according to Claim 6, characterized in that
   the guide pin (24) is guided by the second stop (16).
8. Contact press-on assembly (14) according to one of Claims 1 to 7,
   characterized in that
   the first stop (15) and the second stop (16) are guided in a telescoping manner.
9. Contact press-on assembly (14) according to one of Claims 1 to 8,
   characterized in that
   the spring element (17) has a pressure stage.
10. Electrical switching device with a first switching contact piece (3) and a second switching contact piece (4), which are movable relatively in relation to one another,
    characterized in that
    a kinematic chain (10) that serves for a relative movement of the switching contact pieces (3, 4) in relation to one another has a contact press-on assembly (14) as claimed in one of patent claims 1 to 9.
11. Electrical switching device according to Patent Claim 10, characterized in that
    a switching gap (5) is arranged between the switching contact pieces (3, 4) in a vacuum interrupter (1).

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