DE69023703T2 - Switches, in particular for motor vehicles. - Google Patents

Description

The present invention relates generally to electrical switches, in particular for motor vehicles.

Such a switch is described in FR-A-2 221 801 according to the preamble of claim 1.

In it (Figure 4), conductive fixed stops and tilting supports are arranged on a holder. An elastically deformable conductive contact tongue is installed in a tiltable manner in order to bring about contact with the said stops.

An actuating member is movably mounted on the support and comprises a finger for point-to-point contact with the said conductive contact tongue and its actuation. The conductive contact tongue comprises two main arms, each of which rests against one of the tilting supports, as well as a secondary arm for interaction with the said finger of the actuating member.

The main arms form the legs of a U, which are connected at their root by a central section, the said secondary arm being arranged between the main arms and causing a contact pressure of the conductive contact tongue when it touches the fixed stops.

The contact tongue effectively carries a movable contact which selectively passes from a contact located on one of the stops to a contact located on the other stop, thereby causing current interruptions.

This leads to oxidation phenomena and, on the one hand, to the formation of depressions and, on the other hand, to the formation of elevations in the area of the contacts.

All of this has a detrimental effect on both the lifespan of the switch and its performance.

In addition, the finger of the actuator slides along a secondary arm to stress the contact tongue and tilt it, so that the force required for actuation is not as low as desired.

The purpose of the present invention is to eliminate these disadvantages and to provide a switch with a long service life, while at the same time having a low actuation force and offering other advantages.

This object is achieved according to the invention by the characterizing part of claim 1.

According to the invention, the elastic contact tongue is axially movable by being moved by the finger of the actuating member, which cooperates with the tab, thereby bringing about self-cleaning.

When the switch is actuated, at least one of the main arms first performs a rectilinear movement against the relevant conductive fixed stop before assuming a second stable position against the said stop.

Therefore, the point of impact of the main arm on its associated stop is different from the point of contact with this stop.

It can be seen that contact with low friction is established between the contact tongue and its supports, so that any blocking is excluded and the actuation forces are reduced.

Since said bearings come into contact with the conductive contact tongue, but not with the support, and since the shaft is in local contact with the support at the center, it is possible to install the bearings with a low coefficient of friction so that they can pivot in relation to their support.

For this purpose, in one embodiment, the ends of the shaft are each mounted on an axial retaining support, whereby the said end does not come into contact with the bottom of the support.

For local contact with the bracket, the shaft can have a barrel shape in the middle.

Thanks to this arrangement, the conductive contact tongue has a third point of contact with the holder via the shaft, which improves the floating bearing accordingly.

The secondary arm advantageously has a U-shape with legs that connect to the free ends of the main arms, whereby the said main arms form the legs of a U, inside which the secondary arm is received.

Thanks to this arrangement, the secondary arm has a large length and good flexibility, which in turn has a positive effect on the creation of sufficient Contact pressure of the contact tongue when touching the fixed stops.

The tab passes through the plane of the contact tongue and has an inclined part which facilitates the tilting of the contact tongue and, if necessary, the creation of a secondary circuit.

According to a characteristic of the invention, one of the arms comprises a contact point in a projecting manner for interaction with its associated conductive fixed stop of smooth shape, while the other main arm is smooth for interaction with a contact point located in a projecting manner on its associated conductive fixed stop. The contact points can be attached contact pieces or contact discs or, as a variant, scaly or curved areas.

Thanks to this arrangement and thanks to the elastic contact tongue, which is mounted in a floating manner according to the invention, there is an alternating sequence of contacts, whereby a first contact point can be the first to become effective, while the second contact point is released for further interaction after the first contact point has worn out, and vice versa.

The handle can be covered by a styling element or, as a variant, it can be exposed to the action of a tilting device accessible to the user.

The holder advantageously comprises two housing halves with current paths, each of which is connected to a central part via a hinge. The current paths also have thinner areas so that installation is carried out by means of transverse folding, with the two housing halves being closed by a base.

By exchanging the bases, it is possible to create a push button, a single-function toggle switch, a double-function toggle switch or a grouping on a multi-function keypad.

The following description illustrates the invention with reference to the accompanying drawings, in which:

- Figure 1 shows a sectional view of a switch according to the invention to one of its stable positions.

- Figure 2 shows a sectional view along the line II-III of Figure 1.

- Figure 3 shows a sectional view along the line III-III of Figure 1.

- Figure 4 shows a partial view of Figure 1 on an enlarged scale.

- Figure 5 shows a view similar to Figure 1 of a first application of the push button type.

- Figure 6 shows a view similar to Figure 1 for an application as a single-function toggle switch.

- Figure 7 shows a view similar to Figure 1 for an application as a dual-function toggle switch.

- Figure 8 shows a front view showing a grouping on a multifunction keypad.

- Figure 9 shows a sectional view along the line IX-IX of Figure 8.

In Figure 1, the switch for motor vehicles comprises a holder 1 - preferably made of plastic - on which conductive fixed stops 2 to 7 are located, which each ending in a connecting pin, and tilt supports 8, 9 are located.

The fixed stops 2 to 7 belong to conductive current paths, which are described below.

An elastically deformable conductive contact tongue 10 is tiltably mounted in the holder 1 in order to come into contact with some 2, 3 of the fixed stops 2 to 7.

An actuating member 20 is movably mounted on the support 1 and comprises a finger 21 for local contact with the said conductive contact tongue 10 and its actuation.

The contact tongue 10 comprises two main arms 22 and 23, each of which is intended to come into contact with one of the tilting supports 8, 9, and a secondary arm 24, which is arranged between the main arms 22, 23 in order to come into contact with the finger 21. The main arms form the legs of a U, being connected to one another at their root by a central section 29, while the secondary arm brings about a contact pressure of the contact tongue 10 when it comes into contact with the fixed stops 2, 3 in the manner described below.

According to the invention, said fixed stops 2, 3 extend on the side of the free ends of the U-legs of said contact tongue 10 and are each connected to the free end 25, 26 of a main arm 22, 23 to cooperate with it. Said main arms 22, 23 each rest on a low friction bearing 8, 9 forming the tilting support. Said bearings 8, 9 are connected and supported by a shaft 50, being arranged at a distance from the support 1. Between the support 1 and the central part of the shaft 50, point contact means are provided to enable radially pivoting installation of the bearings 8, 9 and the shaft 50. Between the elastic contact tongue 10 and the actuating member 20, hooking means 31, 67 are provided for driving the said contact tongue 10 by the actuating member. The secondary arm 24 is connected to the free ends of the main arms 22, 23. The secondary arm 24 carries centrally, projecting radially, between the two main arms 22, 23 on the side of the central section 29 of the U, a tab 30 for cooperation with the said finger 21 of the actuating member, said tab 30 comprising an inclined region 33 which can cooperate with the central part of the shaft 50. The actuating member 20 consists of a push-button mounted on the support 1 so as to be able to move in a straight line by means of straight connection means 61, 62, said push-button 20 being subjected to the action of engagement means 40 which urge it towards a first stable position in which the conductive contact tongue 10 extends at a distance from the fixed contacts 2, 3, and which can assume a second stable position in which a connection is made between the fixed contacts 2, 3 by the conductive contact tongue 10 which is kept pressed against them by the secondary arms 24.

In this way, the contact tongue 10 is hooked by its secondary arm 24 onto the pusher 20 to form a movable unit, said pusher being guided by the support 1.

In the further course of the description, the bearing with a low friction coefficient 8, 9 is referred to as antifriction bearing.

In Figure 1, the pusher 20 is designed to be axially movable against elastic engagement means 40, which allow it to towards a first stable position.

In this figure, the antifriction bearings 8, 9 are rolling elements and consist of rollers 8, 9 connected and supported by a shaft 50, the reduced diameter ends of which are rotatably mounted in axial retaining supports 51 which are fixed to the support 1 which is locally recessed for the passage of the said rollers (Figures 1 to 4).

The rollers 8, 9 are here firmly connected to the shaft 50 and form a one-piece part made of conductive material, the rollers 8, 9 being arranged near the inside of the supports 51 so that the said supports 51 form stops perpendicular to the plane of Figure 2.

According to an important feature of the invention, the shaft 50 has a barrel-shaped bulge in the middle (Figure 2) in order to bring about a point contact, here indirectly via a current path 4, with the holder 1.

This barrel-shaped area is located opposite the tab 30.

On the supports 51, the end of the shaft is not in contact with the bottom of the support 51, while the rollers 8, 9 only come into contact with the contact tongue 10, the lower part of said rollers being arranged at a distance from the support 1, which is brought about by the aforementioned local recesses of the support in the area of the rollers.

As will be understood, thanks to this arrangement, the shaft 50 with its rollers 8, 9 forms a radially pivotable unit, with its axial movement being limited by the supports 51.

The secondary arm 24 connects to the free ends 25, 26 of the main arms 22, 23.

The fixed stops or current paths 2, 3 extend parallel to the arms 22, 23. Note the presence of the current path 4 between the current paths 2 and 3, which enables the creation of a function control circuit by interacting with the bulged part of the shaft 50.

At the free end 25 of the arm 22 (Figure 2) there is a contact point 27 for interaction with the associated conductive stop or the associated current path 2, whereby the said point 27 is smooth. The free end 26 of the arm 23 is smooth and can interact with a contact point 28 which is arranged on the other conductive stop or the other current path 3. The contact points 27, 28 here consist of attached contact pieces or contact disks doped with silver.

As a variant, the contact points 27, 28 can be formed by curved or scale-shaped areas of the relevant parts 10, 3.

It should be noted that the secondary arm 24 is separated from the main arms 22, 23 by a slot 11 and that the two arms 22, 23 form the legs of a U, being connected to one another at their root by a central section 29.

The arm 24 therefore also has the shape of a U, which is arranged inside the U of the arms 22, 23, with a base 12 parallel to the section 29 and legs that run parallel to the inner contour of the arms 22, 24. These arms 22, 23 widen towards their free ends 25, 26 in order to enlarge the contact surfaces with the current paths 2, 3 and to Connection with the corresponding leg of the arm 24.

The tab 30 is hook-shaped and rises locally in the middle from the base 12 of the arm 24 (Figure 2). It comprises a radial section 31 for hooking onto the pusher 20, whereby this section 31 merges into a rounded section 32 for local and punctual contact with the finger 21 with a rounded end.

This tab 30 extends on the other side of the plane of the contact tongue 10 and comprises an inclined region 33 which can cooperate with the barrel-shaped central section of the shaft 50.

The pusher 20, which is advantageously made of plastic, comprises two rounded local contact surfaces 41, 42 for interaction with the holder 1.

This pusher is designed in the shape of a parallelepiped with a narrower front part and a rear part, on which the contact surfaces 41, 42 are located and which connects to the part in front via an inclined area (see Figures 3 and 4).

The engagement means 40 here consist of a helical spring resting on the base 60 of the support 1, surrounding an axial protuberance 61 with a cross-shaped cross section which penetrates into an opening 62 of a matching shape provided at the front end or front face 63 of the pusher 20. This pusher 20 has an open top for the passage of a control lamp 64, which can illuminate the open rear face 65 of the said pusher 20.

The bottom 66 of said pusher locally bears the Finger 21 with a rounded end and a conically enlarged opening 67 for the penetration of the section 31 and its hooking onto the pusher 20.

The pusher 20 forms a driving element, and the section 31 with its associated opening 67 hook-in means between the contact tongue 10 and the pusher 20.

In this way, the pusher 20 and the tab 30 form a unit that can move axially in both directions, wherein the said contact tongue 10 is hooked with its tab 30 on the pusher 20 guided through the holder 1.

The base 66 extends partially above the contact tongue 10. One of the side surfaces of the pusher 20 has a labyrinth 70, which is provided with a central projection 71 and with insertion areas 72, 73. For the shape of the labyrinth 70, see Figure 4.

This labyrinth shape is commonly referred to as a "heart-shaped cam".

The support 1 has a sliding guide 74 for the displacement of a part 75 on which there is a pin 76 which passes through a slot of the sliding guide 74 and can cooperate with the labyrinth 70 by penetrating it.

The holder 1 has an open front end 80 in the middle, which is delimited by the base area 60. The connection pins of the stops 2 to 7 are arranged in the interior of this end, which here all form current paths in the form of mutually parallel strips of material, the current paths 5 to 7 being intended in particular for the power supply of the lamp 64 and being radially offset in relation to the current paths 2 to 4.

The end 80 with its associated connection pins, which are radially offset in relation to the actual current paths, forms the receiving part of a connection device.

In addition to the axial protrusion 61, housing halves 81, 82 are firmly connected to this end 80, with thinner areas 83, 84 being provided at the level of the connection of each of the housing halves 81, 82 to the base surface 60.

The current paths 2 to 7 also have thinner areas at this point. They can be molded onto the housing halves 81, 82 or, as a variant, can be firmly inserted, whereby pointed wedges firmly connected to the housing halves are provided to hold the said current paths.

As will be understood, the said thinner areas form hinges, so that after the components of the switch have been installed, the holder is assembled by bending and placing the housing halves 81, 82 together in the manner of a transverse fold, the two housing halves 81, 82 being originally arranged vertically in the plane of Figure 4.

In this figure, the position of the housing halves 81 before bending is shown with dashed lines.

It should be noted that the entire unit of the housing halves 81, 82 joined together in this way has a parallelepiped shape.

After this bending process, the whole is secured by a base 90 for attachment to the vehicle, said base 90 also comprising fastening eyes 91 with fastening holes and an axial part for cooperation with the guide surfaces 41, 42 belonging to the bottom 66 and the upper wall of the pusher 20.

In Figures 1 to 4, the switch is in its first stable position, with the spring 40 urging the pusher 20 into contact with the pin 76, which in turn is in contact with the insertion area 72 of the labyrinth 70, while the tab 30 and the finger 21 extend axially on the side of the axis of the shaft 50 which is directed opposite to the base 60.

In this configuration, the contact tongue 10 extends at a distance from the current paths 2 and 3, which are thus no longer connected to each other, so that the associated circuit is opened.

It should also be noted that the pusher 20 has protuberances 68 to bring about local contact with the ends 25, 26 of the arms 22, 23 in this position.

When, starting from the configuration shown in Figure 1, the pusher 20 is pressed, the finger 21 moves the contact tongue 10 by means of the tab 30, and the pin 76 passes through the labyrinth until it comes into contact with the second insertion area 73 formed by the projection 71.

This configuration corresponds to the second stable position of the switch, in which a connection is established between the current paths 2 and 3, which is achieved by the contact tongue 10 which is held pressed against it by the arm 24.

During this phase, the contact tongue 10 passes through the axis of the shaft 50, whereupon, when it passes to the other side of said axis 50, while one of its main arms 22, 23 comes into frictional contact with its associated front current path, it tilts the other main arm.

As should have become understandable, the U-shaped geometry gives the secondary arm 24 a certain flexibility, so that the contact tongue 10 is mounted in a floating manner during its displacement.

In this context, it should be noted that the contact tongue 10 can initially come into contact with one of the current paths and that it comes into contact with the other current path via the rollers 8, 9 and the radially pivoting shaft 50, so that in the course of its movement it finds three contact points on the support 1, namely two contact points on the current paths 2, 3 and a third contact point at the height of the central part of the shaft 50.

It should also be noted that the contact tongue 10 in this second position enables the creation of an additional circuit, which is achieved via the shaft 50, the current path 4 and, above all, via the section 33 of the contact tongue 10.

When the pusher is pressed again, the pin 76 is released, whereupon it returns to its original starting position under the action of the spring 40, the contact tongue 10 being carried along by the pusher 20 via the section 31.

The push button 20 can of course be covered with a styling element 95 accessible to the user, as can be seen in Figure 5, the switch being actuated by pressing it in the direction of the arrow shown in this figure.

As a variant (Figure 6), the slide can be operated by the action of a tilting device 96 accessible to the user.

In this case, the presence of the labyrinth is no longer necessary, which is made possible by the installation of a new base 100. The said base 100 then carries pivots 98 for the tiltable installation of the tilting device 96, on which there are projections 99 on the sides, each of which can engage in a corresponding hole in the base 100 for each position of the pusher 100 in order to secure it in its position.

For this purpose, the pusher 200 has an extension 97 in the extension of its base 66.

When the tilting device 96 is actuated, it presses on the extension 97 and moves the slide 200.

By installing the brackets 130, 140 with their associated pushbuttons 201, 202 and their contact tongue 10 in the opposite direction in the standard version, a dual-function toggle switch (Figure 7) can be produced.

Of course, using a base 190 and supports with elastic contact tongue and standard pushbuttons, it is possible (Figures 8 and 9) to create a multifunction keypad with single or multifunction toggle keys and pushbutton type keys, while still allowing the installation of certain supports.

The present invention is of course not limited to the described embodiments.

In particular, the rolling elements can be made of ball bearings and the anti-friction bearings can consist of profiled bearings with a low coefficient of friction.

The said bearings can, for example, be inserted radially between the contact tongue 10 and the ends of the shaft 50, whereby they are secured against twisting by the supports 51.

The rollers can be separate from each other. The hooking of the pusher 20 onto the tab 30 can be carried out by means of the finger 21 and a part attached to the pusher in the form of a hook, which engages in the slot 11 in order to return the contact tongue 10. Instead of a protuberance 61 with a cross-shaped cross section, a straight connection by means of a flat or similar can be used.

The secondary arm 24 may consist of a flexible strip connected to the main arm 22, 23. In all cases, the current can flow from one main arm 22, 23 to the other, which can also take place via the secondary arm 24, so that the voltage drops are reduced.

As a variant, the shaft 50 may have a central over-thickness of cylindrical shape in order to achieve a point contact, which can cooperate with a single-piece strip extending transversely with respect to the said shaft.

In this case - as in the case of Figure 2 described above - means are provided for a point contact between the holder 1 and the middle part of the shaft 50, this contact being made either directly or indirectly via the current path 4.

The fixed stops 2, 3 may not run parallel to each other, since one has a projection for interaction with the contact tongue 10.

Claims (12)

1. Switch, in particular for motor vehicles, comprising a support (1) on which there are at least two conductive fixed stops (2, 3) and tilting supports (8, 9), an elastically deformable and tiltable conductive contact tongue (10) for contact with said fixed stops (2, 3) and an actuating member (20) movably mounted on the support (1) with a finger (21) for local contact with said conductive contact tongue (10) and for actuating it, said conductive contact tongue (10) comprising, on the one hand, two main arms (22, 23) forming the legs of a U, connected at their base by a central portion (29) in order to come into contact with one of the tilting supports (8, 9) respectively, and, on the other hand, a secondary arm (24) arranged between the main arms (22, 23) in order to contact said finger (21) of the actuating member (20) and to bring about a contact pressure of the conductive contact tongue (10) when the fixed stops (2, 3) come into contact, characterized in that the said fixed stops (2, 3) extend on the side of the free ends of the U-legs of the said contact tongue (10) and are each connected to the free end (25, 26) of a main arm (22, 23) in order to cooperate therewith, that the said main arms (22, 23) each rest on a bearing with a low coefficient of friction (8, 9) which supports the tilting support that said bearings (8, 9) are connected and supported by a shaft (50) arranged at a distance from the support (1), that point contact means are provided between the support (1) and the central part of the shaft (50) to enable a radially pivoting installation of the bearings (8, 9) and the shaft (50), that between the elastic contact tongue (10) and the actuating member (20) there are provided hooking means (31, 67) for the said contact tongue (10) to be carried along by the actuating member (20), that the secondary arm (24) is connected to the free ends of the main arms (22, 23), that the secondary arm (24) has centrally, projecting radially, between the two main arms (22, 23) on the side of the central portion (29) of the U, a tab (30) for cooperation with the said finger (21) of the actuating member (20), said tab (30) comprising an inclined portion (33) capable of cooperating with the central portion of the shaft (50), and in that the actuating member (20) consists of a pusher mounted on the support (1) so as to be movable in a straight line by means of straight connection means (61, 62), said pusher (20) being subjected to the action of engagement means (40) which urge it towards a first stable position in which the conductive contact tongue (10) extends at a distance from the fixed contacts (2, 3), and being capable of assuming a second stable position in which a connection is made between the fixed contacts (2, 3) by the conductive contact tongue (10) which is held pressed against them by the secondary arms (24). 2. Switch according to claim 1, characterized in that the secondary arm (24) has the shape of a U which adjoins the free ends (25, 26) of the main arms (22, 23), being accommodated inside the U-shape with the main arms (22, 23), and that the tab (30) is attached to the base (12) of the U of said secondary arm. 3. Switch according to claim 1 or 2, characterized in that said low friction coefficient bearings (8, 9) are connected to a shaft (50) whose ends are housed in axial retaining supports (51) which are locally recessed to allow passage of said bearings (8, 9) and to keep them at a distance from the support (1). 4. Switch according to claim 3, characterized in that the low friction coefficient bearings (8, 9) consist of rolling elements in the form of rollers (8, 9) which are installed at the ends of the shaft (50), the central part of which has a barrel shape. 5. Switch according to claim 3 or 4, characterized in that the central part of the shaft (50) can cooperate with an additional power supply track (4) and that the said rollers (8, 9) and the said shaft (50) are made of metal. 6. Switch according to one of the preceding claims, characterized in that the conductive fixed stops (2, 3) consist of conductive current paths (2, 3) which extend parallel to the main arms (22, 23), and in that one (22) of the main arms (22, 23) carries in a projecting manner a contact point (27) for cooperation with its associated conductive current path (2) of smooth shape, while the other main arm (23) is made smooth for cooperation with a contact point (28) which is located in a projecting manner on its associated conductive current path (3). 7. Switch according to one of claims 1 to 6, characterized in that the tab (30) is hook-shaped and rises locally in the middle from the base (12) of the secondary arm (24) and that the tab (30) comprises a radial portion (31) which engages in an opening (27) of the pusher (20) in order to hook onto the latter. 8. Switch according to claim 7, characterized in that said radial portion (31) is extended by a rounded portion in order to bring about a local and punctual contact with the finger (21) with a rounded end. 9. Switch according to one of claims 1 to 8, characterized in that the pusher (20) is guided by an axial protuberance (61) with a cross-shaped cross-section, which is firmly connected to the support (1), and in that the engagement means (40) consist of a helical spring which comes to rest on the support (1) and on the pusher (20), the said spring (40) surrounding the said axial protuberance (61). 10. Switch according to one of claims 1 to 9, characterized in that the pushbutton (20) has a side surface provided with a labyrinth (70) on which a central projection (71) and insertion areas (72, 73) are located, wherein said labyrinth (70) is a heart-shaped cam. 11. Switch according to claim 1, characterized in that the holder (1) has a sliding guide (74) for the displacement of a part (75) on which there is a plug-in pin (76) which passes through a slot in the sliding guide (74) and cooperates with the labyrinth (70) can by penetrating it. 12. Switch according to one of the preceding claims, characterized in that its holder (1) comprises two housing halves (81, 82) which each connect to a central part (80) via thinner regions (83, 84).