Patent Application
20230132857
This application claims the benefit of the filing date under 35 U.S.C. § 119(a)-(d) of German Patent Application No. 102021128179.2, filed on Oct. 28, 2021.
The invention relates to a switching contact assembly for an electrical switching element, such as a contactor or a relay, and an electrical switching element.
In switching contact assemblies and electrical switching elements, an overtravel spring is generally used to ensure reliable contacting of a contact bridge with mating contacts.
In an attempt to downsize electrical switching elements, it is necessary to make the switching contact assemblies smaller as well. However, downsizing the overtravel spring is a problem. With smaller overtravel springs, it is difficult or impossible to precisely adjust the spring force with which the contact bridge is pressed against mating contacts, because existing overtravel springs have relatively high tolerances for the spring force that can be generated per spring length.
A switching contact assembly for an electrical switching element includes a contact bridge, a base, and a spring assembly. The contact bridge is attached to the base with the spring assembly between the contact bridge and the base. The contact bridge attached to the base is resilient in a direction opposite a switching direction.
The invention will now be described by way of example with reference to the accompanying Figures, of which:
The invention shall be further explained hereafter on the basis of an embodiment with reference to the figures. Individual features that are advantageous by themselves can be added or omitted in the embodiment described.
The representation shown is purely by way of example and other configurations of electrical switching element 1 can have a different number of power contacts 3 and drive contacts 5 and/or different positioning of the power contacts 3 and drive contacts 5. The power contacts 3 can be configured as fixed contacts 3 permanently installed in switching element 1 and immovable. The drive contacts 5 can be configured as a plurality of coil terminals 5 which can be connected to a drive, e.g. a coil of switching element 1.
A switching contact assembly 7 for switching the power contacts 3, which is shown in
As shown in
The base 11 can consist of electrically non-conductive material and can therefore represent a galvanic isolation. In an embodiment, the contact bridge 9 can be galvanically isolated from other elements.
Contact bridge 9 is furthermore attached to base 11 by way of spring assembly 13. An actuating element 17 extending along an axis 15 is likewise attached to base 11, as shown in
In the embodiment shown, spring assembly 13 of switching contact assembly 7 comprises two spring elements 21 bearing directly against one another. A first spring element 21a of spring assembly 13 is inserted into a second spring element 21b of spring assembly 13, as shown in
A spring element 21, second spring element 21b of spring assembly 13 in the embodiment shown, is configured as a contact bridge retainer 23. Contact bridge retainer 23 holds contact bridge 9 at base 11. Various devices can be used to attach the second spring element 21b to the base 11. Purely by way of example, the second spring element 21b can be clipped on, adhesively bonded, riveted or screwed on.
Another spring element, first spring element 21a of spring assembly 13 in the embodiment shown, is arranged between contact bridge retainer 23 and contact bridge 9. The first spring element 21a and/or the second spring element 21b, i.e. also the contact bridge 9, can be a punched and bent part, i.e. manufactured to be punched out of sheet metal.
The spring assembly 13 can also be formed by more than two spring elements that bear directly against one another. The spring force of the spring assembly 13 can be scaled with the number of spring elements.
The spring elements 21a, 21b can be deflectable away from the contact bridge 9. Two symmetrical spring legs may be provided for every spring element 21a, 21b and can be deflectable symmetrically. In particular, the at least two spring elements 21a, 21b can each bear directly against one another with their central region or section. The spring elements 21a, 21b can bear entirely directly against one another along a longitudinal extension. The longitudinal extension of a spring element 21a, 21b or the contact bridge 9 corresponds to a direction that lies in a plane that is spanned by the deflecting spring assembly. Accordingly, a transverse direction can be defined which can be defined to be perpendicular to this plane spanned by the deflecting spring assembly 13.
The second spring element 21b can have a configuration that is similar to a cage or can form a cage in which the first spring element 21a is received. The first spring element 21a can be received in a positive-fit manner in the second spring element 21b. The first spring element 21a may be received loosely in the second spring element 21b and can therefore be detached therefrom. If the first spring element 21a is received in the second spring element 21b in a positive-fit manner, the positive-fit connection be established in particular along the longitudinal extension of the spring assembly 13. The second spring element 21b can also be received in the first spring element 21a in a positive-fit manner in a motion relative to the first spring element 21a in and in a direction opposite to the transverse direction. For this purpose, the second spring element 21b can have a cross section that is U-shaped, at least in sections, when viewed in the longitudinal extension.
A region of the first or the second spring element 21a, 21b, around which the respective spring legs can be deflected or deflect in or in a direction opposite to the switching direction 19, can be regarded to be the bending axis. The bending axis can therefore be formed by a volume area of the first and/or the second spring element 21a, 21b and not just denote a (one-dimensional) line.
As shown in the exploded drawing of switching contact assembly 7 according to the invention in
Contact bridge retaining legs 27 form a lug 27a in which a post 28 of contact bridge 9 is received. This prevents a further motion of contact bridge 9 in switching direction 19. The contact bridge retaining legs 27 can then each represent a mechanical stop for the contact bridge 9. The contact bridge 9 is held to be movable up to this stop. In a state of rest of the spring assembly, the posts 28 of the contact bridge 9 can bear against the stops.
When the spring assembly 13 is at rest, it can be preloaded. Contact bridge 9 is supported by spring assembly 13 in the direction opposite to switching direction 19. The contact bridge retaining legs 27 can be oriented parallel to the switching direction 19 and face each other along the transverse direction 25.
As shown in
The attachment projections 29 can be, for example, lugs that are punched out and particularly extend to be perpendicular to the switching direction 19. The second spring element 21b configured as a contact bridge retainer 23 can then be connected to the base 11 and at the same time the first spring element 21a can be inserted (in a positive-fit manner) into the second spring element 21b. The attachment projections 29 can be provided in pairs, but switching contact assemblies with an odd number of attachment projections 29 are also conceivable.
The orientation of the attachment projections 29 may be perpendicular to the switching direction 19, so that a spring force of the spring assembly 13 acting in the switching direction 19 acts perpendicular to the attachment of the second spring element 21b to the base 11 by way of attachment projections 29. This has the advantage that, when the switching contact assembly 13 is actuated in the switching direction 19, precisely the connection between the second spring element 21b and the base 11 cannot be released at the base 11.
The bending axis can extend between two attachment projections 29 so that the deflecting spring legs are mounted in that region of those spring elements 21a, 21b that also comprises the bending axis. This has the advantage that the attachment of the second spring element 21b to the base 11 and therefore the spring assembly 13 to the base 11 is not or only slightly stressed by a deflection of the spring assembly 13. If the bending axis and an axis of the attachment are not disposed on top of one another or close together, then the deflection of a spring leg of the first or the second spring element 21a, 21b can lead to an excessive force being applied to the attachment axis, since, if the bending axis and the attachment axis are spatially separated, a lever with two lever arms can form and a force acting at the spring leg force can be increased. This can mechanically stress the attachment of the spring assembly 13 to the base 11 or even lead to a defect in the attachment (for example, the attachment projections breaking out of the attachment openings).
In an assembled state 33, shown in
In switching direction 19, first spring element 21a is supported on contact bridge 9 at two mounting points 40 in a manner resilient in a direction opposite to switching direction 19.
Entire spring assembly 13 is therefore supported in a resilient manner on contact bridge 9 by way of mounting points 40, wherein a motion of contact bridge 9 in switching direction 19 is restricted by contact bridge retaining legs 27 configured as lugs 27a. Such a mounting point 40 for the contact bridge 9 can be located at each end of the contact bridge 9 located in and opposite to the longitudinal direction. The mounting points 40 can be punctiform or linear, wherein the linear form is may cause less wear as compared to punctiform contact, and the mounting point 40 of the first spring element 21a is not pressed into the material of the contact bridge 9 even after a large number of switching cycles.
Each mounting point 40 provided by the first spring element 21a can mount the contact bridge 9 in a resilient manner independently of other mounting points 40 by way of a spring leg or several spring legs forming a spring leg assembly. Two mounting points 40 may be provided, while three mounting points 40 are also conceivable.
When switching contact assembly 7 strikes with mating power contacts 3a in switching direction 19 against power contacts 3, contact bridge 9 moves towards base 11, wherein this motion is guided by posts 28 sliding in lugs 27a in a direction opposite to switching direction 19. In the process, spring assembly 13 is deflected in a direction opposite to switching direction 19.
As shown in
The first part 39 of base 11 comprises a projection 47 which is oriented to be substantially perpendicular to switching direction 19. Second part 39′ comprises a recess which is oriented to be substantially perpendicular to switching direction 19 and which is referred to as a further recess 49 to distinguish it from recess 35 in first spring element 21a.
In assembled state 33, projection 47 engages in further recess 49, as shown in
A disk-shaped head 56 of actuating element 53 is inserted into corresponding axis receptacles 57 of parts 39, 39′, wherein in assembled state 33 of base 11, a positive-fit connection forms between axis receptacles 57 and actuating element 53. Actuating element 53 is held by base 11, as shown in
Contact bridge 9 is supported by way of spring assembly 13 in a resilient manner against base 11, wherein spring assembly 13 is supported by two mounting points 40 on contact bridge 9 and a motion of contact bridge 9 in switching direction 19 is restricted by contact bridge retaining leg 27 that is configured as a lug 27a.
Furthermore, attachment projections 29 comprise latching and/or barbed hooks 58 with which they are attached in attachment openings 55. The latching and/or barbed hooks 58 can displace the material on the inside of the attachment opening 55 and engage in the material of the attachment opening 55. The at least one latching and/or barbed hook 58 of the attachment projection 29 can then prevent the attachment projection 29 from being able to be removed from the attachment opening 55. The plugging process can therefore be non-reversible.
The attachment of contact bridge 9 to base 11 is therefore perpendicular to switching direction 19. When switching contact assembly 7 is actuated, the connection between attachment projections 29 and base 11 can therefore be prevented from detaching.
The switching contact assembly 7 and electrical switching element 1 which ensure a sufficiently high and sufficiently precisely adjustable spring force in the smallest possible installation space.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102021128179.2 | Oct 2021 | DE | national |
