Synchronous double microswitch

Abstract

Double microswitch with two synchronously switching circuits that are electrically independent of each other but perform an electrical switching function simultaneously, with leaf spring (4), contact elements (9, 10) and bridge (13) which form a movable leaf spring contact that acts as a snap contact switching the electrically independent circuits, wherein the contact elements (9, 10) exert a preload on the upper contacts (15, 17) when switching at a changeover point due to the spring property of the leaf spring (4) and a preload on the lower contacts (16, 18) when switching back at the changeover point.

Description

[0001] Synchronous double microswitches are available in various designs and technical operating principles; see, for example, DE 10 2012 013 707 A1. These microswitches are used in applications where two circuits must switch simultaneously, resulting in nearly simultaneous electrical signals. While various designs of double switches of this size are known, this new development was implemented with a focus on higher precision and more efficient design.

[0002] The task is to achieve a precise double switch for the simultaneous switching of the two circuits.

[0003] A double microswitch according to the invention has the features of claim 1. In particular, it is provided that the double microswitch has two synchronously switching circuits that are electrically independent of each other but perform an electrical switching function simultaneously, with a leaf spring, contact elements, and a bridge, which form a movable leaf spring contact that acts as a snap contact switching the electrically independent circuits. The contact elements exert a preload on the upper contacts during switching at a changeover point due to the spring properties of the leaf spring, and a preload on the lower contacts during switching back at the changeover point. The simultaneous switching is preferably achieved by the leading snap-action of the middle arm and the bridge before the contact arms lift off.

[0004] Preferred embodiments of the invention are set out in the further claims and in the description in general.

[0005] The invention relates to the development of a double switch consisting of two electrically isolated circuits, each configured as a changeover switch. For the application of these switches, among other things, absolutely synchronous changeover contacts are required. This means that the switching process must be synchronous, so that the electrical signals from both circuits occur almost simultaneously, with the switching signal being delayed by a maximum of a few milliseconds.

[0006] To achieve synchronous switching, a changeover contact is developed, designed as a parallel contact. Each of the two circuits has a movable changeover contact to ensure electrically isolated switching. To achieve this switching function with a leaf spring contact system, a cut contour is defined that guarantees electrical isolation of the two circuits but can be manufactured from a single part.

[0007] The two spring-loaded contact elements rest on their respective fixed contacts with a preload in both the rest position and the switching state. This preload is maintained until the switching point, ensuring reliable electrical contact at all times when the leaf spring snaps into place. This means that until the leaf spring contact system switches due to actuation at the point of application and the central arm with the plastic bridge snaps into place, the preload of the contact elements ensures reliable contact in both circuits, thus guaranteeing simultaneous electrical switching. The two spring-loaded contact elements are mechanically connected by a plastic element and switch simultaneously when the leaf spring contact system is actuated. The leaf spring contact system therefore also contains a leaf spring that provides the spring and switching force for both switching systems.

[0008] By designing the leaf spring contact system as a spring element, and also as a rigidly connected element, it enables the function as a simultaneously switching contact system, which, however, ensures reliable contact in the rest position and also in the switched state.

[0009] Advantageous embodiments of the invention are explained in more detail below with reference to the drawings. These show: Fig. 1 a double microswitch in a central longitudinal section, with a leaf spring in the upper position, Fig. 2 the microswitch according Fig. 1 in a switching position, Fig. 3. the microswitch according to Fig. 1, with the leaf spring in the lower position, Fig. 4. A top view of the microswitch without cover and without plunger, Fig. 5 a side view of the leaf spring with bridge, Fig. 6 a top view of the leaf spring with bridge according to Fig. 5.

[0010] The double microswitch shown in the figures is designed for the synchronous or simultaneous switching of two circuits and accordingly has two armature contact terminals 25, 26, two upper contact terminals 27, 28, and two lower contact terminals 29, 30 on its underside. The microswitch incorporates a leaf spring contact system such that two independent, conductive contact elements 9, 10 are implemented as movable contacts via a bridge 13, which functionally acts as a single contact, thus achieving simultaneous switching. The bridge 13 is made of plastic and / or is electrically non-conductive. The leaf spring contact system consists of the two conductive contact elements 9, 10, a leaf spring 4, the central arm 21, and the bridge 13. The leaf spring 4 transitions into the central arm 21. The bridge 13 connects the central arm 21 to the outer contact elements 9, 10.The contact elements 9, 10 are connected to armature contacts and the armature contact terminals 25, 26, see in particular . Fig. 4.

[0011] The leaf spring contact system is positioned at the contact support 2, notch bearing 7, counter bearing 3, and upper stop 20. Actuating the plunger 6 moves the leaf spring 4 downwards at its point of application 5, so that the tab 12, upon passing the bearing point 7, causes the movable contact to switch with the contact elements 9, 10, the center arm 21, and the bridge 13. During this process, the center arm 21 moves from the upper stop 20 to the lower stop 22, with the positions of the stops 20 and 22 determining the changeover of the leaf spring contact system.

[0012] The contact 2 between contact element 9 and upper contact 17 switches to contact 14 between lower contact 16 and contact element 9. The second current path is initially from contact element 10 to upper contact 15 and, after switching, from contact element 10 to lower contact 18. The leaf spring contact system is designed such that contact elements 9 and 10 are pre-tensioned by contact with upper contacts 15 and 17, respectively, and with lower contacts 16 and 18, respectively, resulting in an almost simultaneous electrical switching behavior during the transition.

[0013] The preload of the leaf spring 4 achieves the contact force for the contact surfaces 2, 23 and 14, 24. A preferred feature is that the leaf spring 4 is connected at position 8 by the plastic bridge 13, is manufactured as a single unit, and therefore exhibits the precision of a complete leaf spring contact system. This results in a precise double microswitch and fulfills the requirement of simultaneous switching with very tight functional tolerances, e.g., + / - 0.2 mm for the switching point.

[0014] The second important criterion is the switching hysteresis, i.e., the actuation path of the plunger 6 from the switching point from contact surface 2 to contact surface 14 and the resulting return stroke (return point) from contact surface 14 back to contact surface 2. This design of the leaf spring contact system 4, 9, 10, 13 achieves the described function of a leaf spring element with switching contacts.

[0015] Advantageously, the connection of the leaf spring 4 to the bridge 13 is provided as far forward as possible at position 8 between the contact elements 9, 10. This ensures that the leaf spring 4 is decoupled from the rigid area of ​​the movable contact.

[0016] The contact elements 9, 10 extend parallel to the end-end center arm 21, which rests against an upper stop 20 before switching and, after switching, rests on a lower stop 22 in an end position. The center arm 21 supports the described switching hysteresis. The connection of the bridge 13 to the contact elements 9, 10 is provided at position 1.

[0017] Positions 1 and 8 are significantly spaced apart along the longitudinal direction of the central arm 21 / contact elements 9, 10. To accommodate this, the bridge 8 is essentially V-shaped. Fig. 4, Fig. 5 as a V lying on the right side. As a result, the elastic areas of the contact arms 9, 10 are significantly longer than a free end of the central arm 21, see left in Fig. 5.

[0018] For some applications of such a switch, the switching noise is of great importance. That is, there should be no loud or disruptive switching noise during the switching process. This is achieved by the spring-loaded contact arms 9 and 10 and the center arm 21, which are made of very thin spring material. Reference symbol list (as part of the description): 1 Connection of contact elements 9, 10 to plastic bridge 13 2 Contact point Upper contact I 3 counter bearings 4 leaf spring 5. Point of attack: plunger on leaf spring 6 pestles 7 notch bearing 8 Connection of leaf spring 4 to plastic bridge 13 9 Contact element I 10 Contact element II 11. Beginning of elastic range, contact element 9, 10 12 End of elastic area Contact element 9, 10 13 plastic bridge 14 Contact point Upper contact II 15 Upper contact I 16 Undercontact I 17 Upper contact II 18 Undercontact II 19. Point of attack: pestle at the top 20 Top stop for the middle arm 21 Middle arm 22 Bottom stop for the middle arm 23 Contact point Sub-contact I 24 Contact point Sub-contact II 25 Anchor contact connection I 26 Anchor contact connection II 27 Upper contact connection I 28 Upper contact connection II 29 Lower contact connection I 30 Lower contact connection II QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2012 013 707 A1

[0001]

Claims

[1] Double microswitch with two synchronously switching circuits that are electrically independent of each other but perform an electrical switching function simultaneously, with leaf spring (4), contact elements (9, 10) and bridge (13) which form a movable leaf spring contact which acts as a snap contact switching the electrically independent circuits, wherein the contact elements (9, 10) exert a bias on the upper contacts (15, 17) when switching at a changeover point due to the spring property of the leaf spring (4) and a bias on the lower contacts (16, 18) when switching back at the changeover point. [2] Double microswitch according to claim 1, characterized by a design with spring-loaded contact elements (9), (10) and a spring-loaded central arm (21) for the leaf spring (4), in particular to achieve very low switching noise. [3] Dual microswitch according to claim 1 or 2, characterized by, that the leaf spring (4) is positioned in a position symmetrically centered between the contact elements (9, 10) in the same plane. [4] Double microswitch according to one of claims 1 to 3, characterized by , that the contact elements (9, 10) are mechanically firmly connected to the leaf spring (4) by the bridge (13). [5] Double microswitch according to one of claims 1 to 4, characterized by , that a connection (8) of the leaf spring (4) is fixed at its outermost end in the bridge (13) and that the contact elements (9, 10) have an elastic range from a position (11) to a position (12), wherein the connection (1) to the bridge (13) is connected to the position (12) outside the elastic range.

Images