DE9300501U1 - Electrical switching device - Google Patents

Description

ABB Patents GmbH

Mannheim 21 January 1993

Mp. No. 93/509 PAT 7-Mi/Ha

Electrical switching device description

The invention relates to an electrical switching device, in particular a pushbutton switch for actuating or controlling actuators for electrically operated devices in motor vehicles, e.g. window lifters, mirror adjusters, etc., with a base for receiving or fastening switching devices and actuating elements.

It is a general standard to design the switching devices intended for operating electrical equipment in motor vehicles so that they are both clear and compact for reasons of space. This applies in particular to switching devices that are intended to carry out several different switching operations.

For operating a sliding or lifting roof of a motor vehicle, a sliding and lever switch is known from DE-PS-39 31 722, which has a sliding or lifting or pressing switch button and a switch housing with switch contacts, whereby the switch button is guided by a mechanical guide so that only a sliding movement or a swivel movement is possible. The intention here is to match the sliding movement of the switch button to the sliding movement of the sliding roof.

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when opening or closing, while the lifting movement of the lifting roof occurs according to the lifting or lowering operation of the switch button.

A disadvantage of the known design of an actuation switch for operating a sliding-lifting roof is the requirement for an exact guide, which results in high requirements for the accuracy of the manufacturing tools and a not inconsiderable assembly effort.

Other generally known switching devices for operating sliding and tilting roofs of motor vehicles are known from practice as pure sliding or lever switches. In these, the switch button can only be operated in a sliding or swiveling movement. The disadvantage of these known switches is that they do not offer sufficient switching reliability, especially when switching small currents, and that they are also complex in their construction.

Having said this, it is the object of the invention to create a switching device of the type mentioned at the outset which is compact in design and as simple as possible in construction and allows easy and cost-effective manufacture and assembly.

According to the invention, this object is achieved by the characterizing features of claim 1.

According to this, it is provided that the base is made of electrically non-conductive material and that at least one contact point is arranged on the base, which has at least two fixed contact pieces that are electrically insulated from one another and can be connected to one another by means of a movable contact piece that serves as a bridge contact.

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In an expedient development of the invention, the base is provided with at least one guide for the movable contact piece, which is advantageously designed as a bore that is let into the base.

This guide, which is provided as a guide hole, serves to clearly define the path of movement of the movable contact piece when the movable contact piece is actuated in order to actuate the contact point and thus to avoid undesirable displacements that can lead to incorrect contact.

In a further embodiment of the invention, the movable contact piece is provided with webs for engagement in the guide holes, which are formed as a single piece or are attached to it using known connection techniques such as soldering, welding, gluing, riveting.

According to a preferred embodiment of the invention, the movable contact piece is made of electrically conductive, spring-hard material, e.g. AgPd. It is expediently, i.e. inexpensive in terms of manufacturing costs, manufactured as a stamped and bent part, which is favorable for automatic production.

A preferred embodiment of the invention provides that the movable contact piece is designed as a triangle, wherein its surface is curved in the shape of a dome and rests with its corners on the base, while its curved central area is at a distance from the base. The corners can each have dimples directed towards the base for better contact with the first fixed contact piece arranged on the base. It is also advantageous if the curved central area of the triangular movable contact piece also has a dimple directed towards the base, which is used for contact with the

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second fixed contact piece, which is located underneath on the base.

A suitable embodiment provides that the first fixed contact piece is divided into three parts and is arranged at each of the corner points of the triangular movable contact piece.

A further embodiment of the invention provides that the webs for guiding the movable contact piece are arranged on its side edges, preferably in the middle, i.e. at half the length, and engage in the corresponding guide holes located underneath in the base.

Due to the intended choice of material, the movable contact piece is designed as a monostable, i.e. self-resetting contact spring, which opens the respective contact in the rest position.

According to the invention, the base, which serves as a contact carrier, can be made of hard paper, e.g. circuit boards, or another suitable insulating material, i.e. with sufficient electrical and mechanical strength, into which the fixed contact pieces are injected or mechanically attached. For connection to the periphery of the switching device, line paths are provided, which can be designed as conductor tracks, as is usual and known for circuit boards, or as current conductors embedded in corresponding recesses, e.g. grooves, and are galvanically connected to the fixed contact pieces.

A significant advantage of the design of the switching device according to the invention is that each contact point consists of very few parts, of which only the movable contact piece, as the name suggests, is movable, in that its spring-elastic central area is acted upon to close the contact and after removal

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load, while the fixed contact pieces are permanently connected to the base. In this design, the switching device according to the invention is particularly suitable for low switching currents, although high switching currents can also be managed.

The provision of guides in conjunction with the reset characteristic of the movable contact piece designed as a triangular contact spring ensures a safe switching function.

Due to the shape of the movable contact piece with a spherically curved triangular surface provided according to the invention, when it is actuated, i.e. when the outer curvature is pressed down, the additional intended effect is that due to the slight displacement of the corner points caused thereby, the contact surface is automatically cleaned during switching and thus incorrect contacts are avoided.

The guidance of the movable contact piece by means of molded-on webs is on the one hand very easy to produce and on the other hand very practical, since it prevents the middle contact from moving, while the previously explained contact cleaning of the outer contacts is still guaranteed.

A further advantage is the very compact design and versatile applicability of the switching device according to the invention, which allows a large number of switching operations to be implemented in the smallest of spaces, whether as a rocker, push button or slide switch, or as a single or multi-way switch. These and other advantageous embodiments of the invention are the subject of the subclaims.

The invention, advantageous embodiments and features thereof are explained in greater detail with reference to the drawings.

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and improvements as well as further advantages of the invention are explained and described in more detail.

Show it:

Figure 1: a contact point of an inventive

Switching device in longitudinal section Figure 2: the contact point according to Figure 1 in plan view

Figure 1 shows a longitudinal section of a contact point 10 of an electrical switching device 12, which is intended in particular for use in motor vehicles and devices with comparable electrical parameters. Due to the structurally intended small contact distances, which accordingly lead to short switching paths, the low voltage range in particular is the preferred area of application for this switching device.

The contact point 10 in the switching device 12 according to the invention is arranged on a base 14, which serves as a contact carrier for first and second fixed contact pieces 16, 18 that are electrically insulated from one another. For this purpose, the base 14 consists of electrically non-conductive material, e.g. insulating material, which has sufficient mechanical strength in addition to sufficient electrical strength.

A movable contact piece 20 is used to connect the first and second fixed contact pieces 16, 18, which are electrically insulated from one another in the resting state, and which acts as a contact bridge when actuated by pressing down and electrically connects the two fixed contact pieces 16, 18 to one another.

As can be seen from Figure 2, the movable contact piece 20 has a triangular shape, with the first fixed three-part contact piece 16 being arranged at the locations opposite the corner points on the base 14, while

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while in the middle of the triangle enclosed by the corner points, the second fixed contact piece 18, which is insulated from this, is arranged in the base 14. On each side of the triangle, halfway along its length, there is a web 22 directed towards the base 14, which in the example shown is connected in one piece to the movable contact piece 20 and engages in a corresponding recess 24 in the base 14. This recess 24 is made as a hole and serves as a guide for the movable contact piece 20 in order to ensure that the second fixed contact point 18 and the contact surface above it in the movable contact piece 20, designed as a dish 26, are always aligned with one another, thus ensuring reliable contact.

The corner areas of the triangular movable contact piece 20 also each have a dish 28, i.e. a bulge directed towards the base 14, which serves to make better contact with the respective associated first fixed contact piece 16 arranged on the base 14. In both cases, i.e. both the dish 26 in the middle of the triangle and the dish 28 at the corner points of the movable contact piece 20 designed as an equilateral triangle, are dome-shaped, i.e. hemispherical, and thus offer the guarantee that, regardless of the respective position of the movable contact piece 20, a secure point contact is made with the associated first or second fixed contact pieces 16, 18.

As can be seen in particular from Figure 1, the movable contact piece 20 has a bulge directed away from the base 14, which is permanently stamped onto the movable contact piece 20, which is preferably made from spring-elastic flat material as a stamped and bent part, and thus causes an automatic reset. If the movable contact piece is therefore acted upon in the direction of arrow F, then

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When the movable contact piece 20 is relieved of pressure, it returns to the initial position shown in Figure 1.

As can also be seen from Figure 2, the contact point 10 has a first fixed contact piece 16 with three contact points, which, as mentioned, are arranged at the corners of an equilateral triangle and are connected to one another by means of line paths 17 arranged in the base 14. To connect the contact point 10 to the periphery, e.g. to connection contacts of the switching device 12 (not shown in detail here), one of the first fixed contact pieces 16 arranged in the base 14 is connected to a first connection line 30 and the second fixed contact piece 18 is connected to a second connection line 32. The further course of the first and second connection lines 30, 32 is not shown in detail in the example shown. These connecting conductors 30, 32 can be designed both as conductor tracks running on the surface and as contact strips, which, when installed in a switch housing (also not shown in detail here), work together with corresponding counter-contact surfaces and thus fulfill the intended electrical function.

Claims (11)

Mp. No. 93/509 1 . 21 January 1993 Claims 1. Electrical switching device (12), in particular a pushbutton switch for actuating or controlling actuators for electrically operated devices in motor vehicles, with a base (14) for receiving or attaching switching elements, such as contact pieces (16, 18, 20), characterized in that the base (14) is made of electrically non-conductive material, and that at least one contact point (10) is arranged on the base, which is formed by at least a first and a second fixed contact piece (16, 18) and a movable contact piece (20), which movable contact piece (20) is designed as a bridge contact and serves for the temporary electrical connection of the fixed contact pieces (16, 18). 2. Switching device according to claim 1, characterized in that the base (14) is provided with at least one guide (24) for the movable contact piece (20). 3. Switching device according to claim 2, characterized in that the guide (24) is designed as a bore which is let into the base (14) and into which the movable contact piece (20) engages. 4. Switching device according to one of the preceding claims, characterized in that the movable contact piece (20) has at least one web (22) which engages in the guide bore (24). 5. Switching device according to one of the preceding claims, characterized in that the at least one guide Mp. No. 93/509 2 21 January 1993 web (22) is integrally formed on the movable contact piece (20). 6. Switching device according to one of the preceding claims, characterized in that the movable contact piece (20) is triangular in shape. 7. Switching device according to one of the preceding claims, characterized in that the movable contact piece (20) is curved in a dome-shaped manner opposite to the direction of extension of the guide web (22). 8. Switching device according to one of the preceding claims, characterized in that the movable contact piece (20) is made of spring material. 9. Switching device according to claim 6, 7 and 8, characterized in that the movable contact piece (20) is self-resetting. 10. Switching device according to one of the preceding claims, characterized in that the movable contact piece (20) has recesses (26, 28) pointing in the direction of the webs (22) arranged thereon. 11. Switching device according to one of the preceding claims, characterized in that a first dish (26) is arranged at each corner point of the triangular movable contact piece (20) and a second dish (28) is arranged in the middle of the triangular surface, which are directed opposite to the dome-shaped curvature and correspond to the first and second fixed contact pieces (16, 18) arranged on the base.