EP0740844A1

EP0740844A1 - Multi-stage switch

Info

Publication number: EP0740844A1
Application number: EP95906250A
Authority: EP
Inventors: Wolfgang Bredow; Thomas Burchard; Thomas Haug
Original assignee: NBB Nachrichtentechnik GmbH and Co KG
Current assignee: NBB Nachrichtentechnik GmbH and Co KG
Priority date: 1994-01-19
Filing date: 1995-01-17
Publication date: 1996-11-06
Anticipated expiration: 2015-01-17
Also published as: DE4401314C2; DE4401314A1; AU1452595A; AU693150B2; ATE157809T1; WO1995020232A1; KR970700925A; US5796056A; EP0740844B1; DE59500608D1

Abstract

PCT No. PCT/DE95/00068 Sec. 371 Date Sep. 12, 1996 Sec. 102(e) Date Sep. 12, 1996 PCT Filed Jan. 17, 1995 PCT Pub. No. WO95/20232 PCT Pub. Date Jul. 27, 1995A multi-stage switch with a common actuating element and at least two switch elements for making contact provides that the switch elements are disposed next to each other above contact elements of a circuit board which they bridge in the closed state. The actuating element for the switch is movably disposed above the switch elements in such a way that the switch elements respond sequentially when the actuating element is depressed. Such a multi-stage switch can be produced cost-effectively with simple structural means, can be universally used, is easy to operate, maintenance free to the greatest extent and operates dependably.

Description

description

Multi-step switch

Technical field

The invention relates to a multi-stage switch with a common actuating element and at least two switching elements for making contacts, the application of which, with increasing force, leads to a successive actuation of the switching elements, the switching elements being arranged on a circuit board above the same-height contact elements, which bridge them in their switched state , with actuation directions perpendicular to this circuit board, and the actuation element being arranged movably above the switch elements in such a way that its actuation area lies between the switch elements.

State of the art.

A generic multi-step switch is known from CH 658 544 A5 (Figure 4). In the multi-stage switch shown there, the switching elements are contact pills, which are held above their associated contact elements on a switching mat which is dome-shaped above the contact elements and carries the contact pills at different heights on projections pointing inwards. This "switch mat" and the contact pills attached to it are actuated via a pressure plate 45 which acts on the dome or dome-like upper sides of the membrane-like sections of the switch mat.

In this known solution, the function of the multiple switch depends crucially on the complex design of the switch matt, for which obviously very long switching paths and a relatively high-profile housing are provided. This may not be a problem in the preferred area of application of the solution according to the previously known publication (keypad blocks for telephone subscriber stations), with increasing miniaturization and other areas of application of such multistage switches, reliable function should no longer be guaranteed, in particular because of the complex construction of the so-called switch mat described above. The difficulties mentioned should at least considerably complicate the manufacture of multistage switches with more than two switching elements.

Presentation of the invention

It is therefore an object of the invention to produce such a multistage switch with minimal design effort and thus inexpensively and simply, with which three or more switching elements in electrical or electronic devices can also be switched, and which can be used universally, is easy to operate, largely is maintenance-free and reliable.

According to the invention the object is achieved according to the characterizing part of patent claim 1.

The basic idea of the invention is therefore to place the switching force acting on the multistep switch outside the actuating direction of the switching elements for their connection or establishment of contact, so that by selecting the distance between the switching force on the one hand and the actuating direction of the individual switching elements, the division the switching force is selectable on the individual switching elements attached to the circuit board. Here, the switching characteristic of the individual switching elements is independent of the movement behavior of the actuating element (in contrast to the subject of the generic device) and can therefore be set extremely easily and reliably by means of an appropriate choice (“hard” or “soft”), as a result of which a reliable Definition of the switching time is also possible with several switching elements, namely precisely when the triggering force of the respective switching element is reached or exceeded by the switching force component acting on this switching element. With this simplified principle and the elimination of complex actuation structures such as the previously known switch mat, solutions can also be implemented without difficulty in which three or more switch elements are to be switched successively in a reliable manner.

Advantageous embodiments of the solution according to the invention can be found in the subclaims.

Brief description of the drawings

Embodiments of the multi-stage switch according to the invention will now be explained in more detail with reference to drawings. Show it

FIG. 1: a schematic diagram to illustrate the principle of the invention,

FIG. 2 shows a longitudinal section of a first exemplary embodiment,

Figure 3:. 2 shows a longitudinal section of a second exemplary embodiment,

FIG. 4: a section in the plane IV-IV of FIG. 3,

5 shows a longitudinal section of the expanded second exemplary embodiment, and

Figure 6: a section in the plane VI-VI of Figure 5.

Description of the embodiments

1 shows the three switching states of a multi-stage switch formed from two switching elements 20 and 30 when the invented principles according to the invention. The two switching elements 20, 30 are located on a circuit board 70, for example the printed circuit board, with conductor tracks which are to be connected to one another at the switching points provided. The switching elements 20, 30 are preferably designed as disc springs ("crack frogs"). The two switching elements 20, 30 are switched by release forces exerted perpendicular to the switching plate 70, the actuation directions A and B of the two switching elements 20 and 30 consequently run through these switching elements and perpendicular to the switching plate 70.

Both switching elements 20, 30 are bridged by an actuating element 10, to which the actuating force F acts from the outside. In this respect, this actuating element 10 can be referred to as a "rocker switch".

The switching path S, caused by the action of the switching force F, also runs perpendicular to the switching plate 70.

It is crucial that the switching path S lies between the actuation directions A and B of the two switching elements 20, 30. In the basic example shown, the external conditions are predetermined such that the switching path S lies in the middle between the actuation directions A, B, so that the switching force F is consequently divided into two identical components F / 2, each of which is divided into two acts on the two switching elements 20,30.

In the initial state shown in FIG. 1A, the switching force F is still relatively low, so that the two components F / 2, which act on the switching elements 20, 30, both below the triggering force FA1 of the switching element 20 and below the triggering force FA2 of the switch 30 lie. The switching force F is therefore insufficient to carry out the first switching operation.

If the switching force F is increased (FIG. 1B), the state is finally reached where the component F / 2 acting on the switching element 20 is equal to or greater than the triggering force FA1 of the switch 20. This has the consequence that the switching element 20 is pushed through, that is, the switch is actuated, and the contact is established between the contact elements on the circuit board 70. Since the component F / 2 of the switching force F, which acts on the other switching element 30, is still below the triggering force FA2 defined there, this is not yet sufficient to actuate this switch. Figure 1B thus identifies the first switching stage.

If the switching force F is further increased (FIG. IC), its component F / 2, which acts on the switch 30, finally also reaches the triggering force FA2 of this switching element 30, so that contact is now also established by means of this switching element, FIG the second stage of the check process.

In the principle example shown, the successive switching of the switching elements 20, 30 is accordingly achieved by a different switching or response characteristic of these two switching elements, with the same switching force component of F / 2. It is immediately apparent that the same effect can also be achieved, for example by shifting the switching direction S of the actuating force F towards one of the switching elements 20, 30; In such a case, switching elements with the same switching characteristics could then also be used, since the different switching time would then be defined by the different values of the force components acting on the individual switching elements.

Figure 2 shows a first embodiment of a multi-stage switch that works according to the principle shown in Figure 1, in which the successive switching of the switching elements is realized by their different response characteristics, so that only the construction of this embodiment will be explained below:

The actuating element 10 is formed by a pressure plate 11, on the central region (in the vicinity of the switching direction S) an attachment 12 is applied, which through an opening 13A stationary cover 13 protrudes outwards and represents the operator area for the user for the multi-stage switch. It must be ensured here that the width of the attachment 12 is matched to the switching characteristics of the specifically used switching elements 20, 30 (eg disc springs) such that even when force is exerted on the edge of the attachment 12 with the consequent change in the force components that act on the two switching elements, the temporal sequence of the two switching operations is still guaranteed.

The stationary cover 13 is usually the housing cover of the electrical device in question, in which the two-stage switching process is to be carried out.

On the underside of the pressure plate 11, a plastic membrane 50 is applied, which serves both to guide the pressure plate 11 and as a restoring element and which for this purpose is held on the edge in side walls of the housing 60 of the electrical device (in this respect, the illustration in FIG. 2 is not true to scale).

Formations ^* 50A, 50B similar to hemispheres are formed on the underside of the plastic membrane 50, the underside of which then serves to act on the switching elements 20, 30. Between the plastic membrane 50 and the switching plate 70 there are a number of spacers 80, 81, 82 which on the one hand limit the switching path of the pressure plate 11 downwards and on the other hand define switching channels K1, K2 which reliably guide the Formations 50A, 50B of the plastic membrane serve from the rest position to the switching position. In particular, these switching channels are designed to taper downwards (frustoconical), so that a secure centering and precise determination of the switching time is facilitated.

In the switched-through state, the two contact elements 71, 72, for example conductor tracks on the circuit board 70 designed as a printed circuit board, are thus bridged, then the contact elements 73, 74 ^' by the other switching element 30. Figures 3 and 4 show a second embodiment of a multi-stage switch, which also works according to the principle shown in Figure 1, but the successive switching of the switching elements is generated by a corresponding shape of the underside of the pressure plate, such that different "Deep" formations are provided which act on the switching elements one after the other.

In the second exemplary embodiment, three switching elements are arranged next to one another (FIG. 4), which are covered by the common pressure plate IV. The switching elements 20 ', 30', 40 'are also located on a common switching plate 70', as in the first exemplary embodiment described above. The pressure plate 11 is also actuated via an attachment 12 ', which acts on the pressure plate 11' in its center (axis S) via a membrane 50 ', which also serves as a restoring element. In the illustrated second exemplary embodiment, the pressure plate 11 'and membrane 50' are therefore reversed in their height order compared to the first exemplary embodiment. Between the membrane 50 'and the circuit board 70' there is a spacing element 80 'in which both a cylindrical guide for the pressure plate 11' and a cone-like guide for the membrane 50 'are embedded coaxially to one another. The switching plate 11 'has on its underside three truncated cone-like shapes 11'a, 11'b, 11'c, which lie centrally above the switching elements 20', 30 ', 40'. The switching elements 20 ', 30' and 40 'used in the second exemplary embodiment shown are metal snap disks with a hysteresis switching behavior (also referred to as' cracking frogs'). When these switching elements are actuated, the contact elements (not shown) underneath are bridged as in the first exemplary embodiment and an electrical connection is thus established. By mutual coordination of the "depth" of the extensions 11'a ... H'c and / or the response sensitivity of the switching elements 20 '... 40' can be achieved when the multiple switch is actuated that the in the cylindrical recess of the Spacer elements 80 'guided pressure plate 11' actuates the three switching elements one after the other, the here too Pressure plate 11 'acts as a "rocker switch" in that a swiveling then takes place successively about two swivel axes inclined to one another.

In its central region (in the axis S), the pressure plate 11 'has a downward-pointing, cylindrical pin 11'd, which defines the maximum deflection of the pressure plate 11' downward, so that the switching plate 70 'serves as a "stop" here. for that pin ll'd. It goes without saying that the effect of this stop can only occur when the two tilting movements about the two pivot axes and the successive actuation of the contact elements have taken place.

In the expanded second exemplary embodiment shown in FIGS. 5 and 6, two multi-stage switches according to FIGS. 3 and 4 are arranged next to one another and are actuated via a common attachment 12 and a common plastic membrane 50 ″. Here six switching elements 20 ... 40 '' are provided, which are actuated by two pressure plates 11 ', 11' 'and the ones below. Switch through or bridge contact elements. Accordingly, there are two actuation areas S1, S2, which can alternatively be selected (for example by corresponding graphic identification on the top of the attachment 12).

Claims

Patent claims

1.Multi-step switch with a common actuating element and at least two switching elements for making contacts, the application of which, with increasing force, leads to a successive actuation of the switching elements, the switching elements (20, 30) being of the same height on contact elements (71 ... 74) on a switching plate (70 , 70 ', 70'') are arranged, which bridge them in their switched state, with actuating directions (A, B, C) lying perpendicular to this circuit board and the actuating element above the switching elements (20 ... 40' ¹ ) in this way is movably arranged that its actuation area (S1.S2) lies between the switching elements, characterized in that the switching elements (20 ... 40 '') are arranged side by side on the common switching plate (70, 70 ', 70''), and that their response characteristics and / or the shape of the actuating element is / are specified such that a rocker-like for successive actuation of the switching elements che pivoting of the actuating element about at least one pivot axis lying substantially parallel to the circuit board.

2. Multi-stage switch according to claim 1, wherein the actuating element includes a pressure plate (11, 11 ', 11' ') which extends over the switching elements and the underside of which acts directly or indirectly, characterized in that only one between the actuating directions (A , B, C) of the switching elements lying actuation area (S) is available for switching actuation.

3. Multi-stage switch according to claim 2, characterized in that above the actuation area of the pressure plate (11) an attachment (12) is attached, which extends through an opening (13A) of a stationary cover (13) at least in the rest position of the actuating element (10) that its top is flush with the top of the cover (13).

4. Multi-stage switch according to claim 2, characterized in that the pressure plate (11) is provided with a Rückstellele ent that lifts the actuating element (10,10 ', 10 ^{, l} ) in the force-free state (rest position) from the switching elements.

5. Multi-stage switch according to claim 1, characterized in that the pressure plate (11, 11 ', 11' ') is guided laterally in a housing (60) or spacer (80, 80').

6. Multi-stage switch according to claim 4 and 5, characterized in that the reset element is a plastic membrane (50, 50 ', 50' ').

7. Multi-stage switch according to claim 1, characterized in that the contact elements (71 ... 74) are conductor tracks on the circuit board (70).

8. Multi-stage switch according to claim 2, characterized in that between the underside of the pressure plate (11) and the switching plate (70) spacer elements (80,81,82, ll'd) are provided, which the switching path of the pressure plate (11,11 ' , 11 ") limit.

9. Multi-stage switch according to claim 8, characterized in that the spacer elements (80,81,82,80 ') protrude beyond the switching elements and define at least one switching channel (K1, K2, K') in which the pressure plate (11) or Membrane (50 ') is immersed indirectly or directly with lateral guidance through the inner sides of the switching channel (K1, K2, K') for actuating the switching elements.

10. Multi-stage switch according to claim 6 and 9, characterized in that the plastic membrane (50) between the flat pressure plate (11) and the spacer elements (80,81,82), and that its underside is shaped so that it is used for successive actuation of the switching elements (20, 30) is immersed in the switching channels (K1, K2).

11. Multi-stage switch according to claim 6 and 9, characterized in that the plastic membrane (50 ') between the pressure plate (11') and the attachment (12 ') and has a central, frustoconical shape, which on the center of the pressure plate (11th ') acts and is guided in channel (K ¹ ).

12. Multi-stage switch according to claim 10 or 11, characterized in that the cross section of the switching channels (K1, K2, K ') for centering the immersing pressure plate (11, 11') or the plastic membrane (50, 50 ') towards the switching plate (70) tapered.

13. Multi-stage switch according to claim 12, characterized in that the inner sides of the switching channels (K1, K2) are frustoconical.

14. Multi-stage switch according to claim 10, characterized in that the underside of the plastic membrane (50) has hemispherical formations (50A, 50B) which protrude into the switching channels (K1, K2) of the spacer elements (80, 81, 82).

15. Multi-stage switch according to one of the preceding claims, characterized in that the switching elements (20 ... 40 ") are disc springs or metal snap disks.