EP0670579B1 - Switching device for connecting and closing an electric line - Google Patents

Description

The present invention relates to a switching device for opening and closing an electrical line, in particular a switch with high frequencies able to work as well with signals continuous, low, medium or high frequencies.

We already know switching devices to open and close a power line in which a contact piece, in blade shape, is supported by a movable operating member in translation between a position in which said contact piece applies to two contact terminals by closing the electrical line, and a position in which it is spaced from said terminals of contact by opening the power line.

During its translational movements, the contact part is guided by rods along which it slides, so ensure proper application of said contact piece against contact terminals.

However, such guidance has the drawback that the friction between the contact piece and its rods guides produce dust which can settle on the electrical contact surfaces and may, over time, degrade the reliability of the switching device.

From document DE-A-2 417 280, there is a switch for electric typewriter keyboard key, in which the organ maneuver carrying the contact piece is guided by two blades parallel hoses which are embedded in a fixed support.

In such a switch, friction is avoided.

There is however the problem that the support of the two flexible blades must be offset from the axis of movement of the operating member, because of the length of the blades which must be sufficient for the latter to have the required elasticity.

Another inherent problem with this known switch comes from because the flexible blades, which form a parallelogram, guide the operating member, not in one direction rigorously axial, but in a translational movement circular.

Therefore, the contacting of the contact piece on the contact terminal is accompanied by a slight slip which can degrade the quality of the electrical contact.

The present invention aims in particular to resolve these problems.

The present invention relates to a device for switching to open and close an electric line, comprising two contact terminals, an operating member comprising a contact, able to be moved axially between a position of closure in which the contact piece is applied simultaneously on the two contact terminals by connecting them electrically and a open position in which the contact piece is moved away two contact terminals, and two parallel flexible blades integral with said operating member, characterized in that the central part of each flexible blade is integral with the maneuver and that each end of each flexible blade is housed in a cradle of a support.

In accordance with the invention, the operating member is located in the central part of each flexible blade, i.e. in the part of the flexible blades where their amplitude of deformation is maximum along the axis of movement of the operating member.

Thanks to the invention, the switch can have a reduced space requirement because the support of the flexible blades can be centered with respect to the operating member, for example by being placed above the two contact terminals of the switch.

Thus, we can make a switch whose size in surface is limited substantially to a rectangle whose length substantially corresponds to the spacing of its two contact terminals and whose width corresponds substantially to that of the piece of contact which connects the two contact terminals.

In this way, you can position several switches according to the invention on the same printed circuit board.

Furthermore, the fact that, according to the invention, the two flexible blades are housed at their ends in a cradle of a support, and not built-in, allows to create a pivot connection between the support and the ends of the blades. This pivot link gives increased flexibility of the blades, without the blades having to have a significant length.

The problem of the axial displacement of the operating member is also solved thanks to the invention, the symmetry of the arrangement of the two blades relative to the operating member ensuring guidance rigorously axial of the latter, without translational movement circular.

In a preferred embodiment of the invention, the member maneuver is moved by means of an axial displacement actuator which acts on at least one flexible control blade, substantially perpendicular to the axis of movement of the actuator, and able to transmit the movements of the actuator to the latter.

The interposition of a flexible control blade between the actuator and the actuator has the advantage that a possible difference in axial travel between the actuator and the operating member can be compensated by a deformation of the flexible control blade.

Indeed, if the actuator transmitted to the organ of maneuver an axial displacement over a greater stroke than the length between its open position and its position closure, it could result in a deterioration of the organ of maneuver or actuator.

Conversely, if the actuator transmitted to the organ of maneuvering a too small amplitude displacement, it could ensue a bad application of the contact piece on the contact terminals and imperfect closing of the power line.

Thanks to the presence of a flexible control blade between the actuator and the operating device, we can deliberately use an actuator which has too much axial movement relative to to the length that the actuator must travel, so as to guarantee that said operating member is moved over a length sufficient to ensure good electrical contact, while preserving the operating member and the actuator of any risk of deterioration.

• la figure 1 représente en perspective un dispositif de commutation selon un mode de réalisation de l'invention, en position ouverte.
• la figure 2 est une vue en coupe selon II-II de la figure 1,
• la figure 3 est une vue analogue à la figure 2, en position fermée.
• la figure 4 représente en perspective un détail de la figure 1,
• la figure 5 est une vue en perspective et de dessous de la pièce de contact et du poussoir des deux dispositifs illustrés, et
• la figure 6 est une vue analogue à la figure 5, après assemblage de la pièce de contact et du poussoir.

In order to better understand the invention, we will now describe an embodiment given by way of non-limiting example with reference to the accompanying drawing in which:

• Figure 1 shows in perspective a switching device according to one embodiment of the invention, in the open position.
• FIG. 2 is a sectional view along II-II of FIG. 1,
• Figure 3 is a view similar to Figure 2, in the closed position.
• FIG. 4 is a perspective view of a detail of FIG. 1,
• FIG. 5 is a perspective view from below of the contact piece and the pusher of the two devices illustrated, and
• Figure 6 is a view similar to Figure 5, after assembly of the contact piece and the pusher.

The switching device shown in the drawing comprises an operating member 1 which comprises a contact part 2, electrically conductive, and a pusher 3, electrically insulating.

The pusher 3 is substantially cylindrical, while the contact part 2 is in the form of a metal strip substantially rectangular.

The contact piece 2 is able to be applied simultaneously on two contact terminals 4, 5 which have contact surfaces 4 a , 5 a , situated in the same plane parallel to the contact piece 2.

As can be clearly seen in the sectional views of Figures 2 and 3, the contact terminals 4 and 5 are each located in a housing provided for this purpose in a conductive body 6, at a distance from the wall of the housing, said terminals being electrically isolated from said body. The conductive body 6 comprises an electrically conductive closure plate 7 in which is formed an orifice 7 a allowing the passage of the pusher 3.

The power line consisting of the two terminals of contact 4, 5 and the contact part 2 is thus protected from any electromagnetic radiation outside the device switching.

In accordance with the invention, the operating member 1 is integral with two parallel flexible blades 8 and 9, the shape of which general rhombus is visible in Figure 1.

Each flexible blade is retained at each of its ends 8a, 9a in a cradle of a support 10.

The support 10 comprises four parallel arms 10 a , each of which comprises a cradle 10 b capable of receiving the end 8a, 9a of a flexible blade 8, 9, said end being simply placed in the cradle where it is immobilized because its dimensions are very slightly smaller than those of the cradle.

However, each end 8a, 9a is free to leave the cradle 10 b in which it is housed.

We can clearly see, in the sectional views of Figures 2 and 3, which the two flexible blades 8, 9 constitute, on either side pusher 3, the two opposite sides of a parallelogram, the pusher 3 constitutes a third side.

We understand that by being thus supported by the blades 8 and 9, pusher 3 can only move according to a movement of axial translation during which the flexible blades 8, 9 flex while remaining parallel to each other.

It also appears clearly, especially in Figures 2 and 3, that the size of the switch is substantially limited to the spacing of the two contact terminals, the support 10 being centered relative to pusher 3.

Figure 2 shows the switching device in the open position of the operating member, the contact part 2 being away from contact terminals 4 and 5.

In the position of the switching device shown in Figure 3, the pusher 3 is in the closed position of the operating member, the contact piece 2 coming to be applied against the two contact terminals 4 and 5.

In this embodiment, the flexible blades 8, 9 have a natural camber that corresponds to that shown in figure 2.

In this way, the flexible blades 8, 9 exert in permanence on pusher 3 a force directed along its axis of movement in the direction indicated by the arrow 11 in FIG. 2.

The pusher 3 transmits this force to the contact part 2 which is thus properly applied against the plate closure 7.

This prevents the contact part 2 from making a coupling between contact terminals 4 and 5 in the open position of the operating member.

FIG. 4 represents an example of a structure making it possible to secure the flexible blades 8, 9 to the pusher 3.

It is a cylindrical spacer 12, which is intended to be placed between the blades 8 and 9, and a cylindrical socket open 13.

The opening of the socket 13 must be sufficiently large to allow the engagement of this one, by a movement of radial translation, on the upper part of the pusher 3.

An internal rib 14 of the sleeve 13 is susceptible, by rotation of the sleeve 13, to cooperate with a groove 15 provided on pusher 3.

Because the cambered blades 8, 9 repel the pusher 3 permanently according to arrow 11, it is not useful to provide a stop between the lower part of the pusher 3 and the blade 9, the part contact 2 fulfilling this stop function by applying against the closing plate 7.

In this part of the pusher 3 located near the closure plate 7, a flexible annular membrane 16 provides a sealing between pusher 3 and closure plate 7.

Thus, not only does the switching device comprise no part which would be capable of producing dust by friction against another part, but also, the membrane 16 provides protection of the contact parts of the device against possible dust which could come from from the outside and enter the housing 6 through the opening 7 a .

An actuator 17, for example electromagnetic, is likely to move along an axis parallel to that of pusher 3.

A control blade 18, secured at one of its ends to a support 19 schematically shown, passes through the end 17 a of the actuator 17.

The other end of the control blade 18 is located at the near the free end of the pusher 3.

It is understood that the control blade 18 is capable of transmit to pusher 3 the translational movements of the actuator 17 which are directed according to the arrow 20 indicated on the Figure 3, to bring the operating member 1 in its position closing.

Conversely, when the actuator 17 moves according to the arrow 21 indicated in FIG. 2, the control blade 18 releases the pusher 3 and deviates slightly to allow the blades pre-bent hoses 8, 9 to bring the operating member 1 back into its open position.

As already explained above, the presence of the blade of control 18 allows the use of an actuator 17 whose travel axial is slightly too large compared to that of the operation 1, which ensures optimum contact between the contact terminals 4, 5 and contact part 2.

In the embodiment which has just been described, it is possible to note that the use of flexible blades makes it possible to orient suitably the contact piece 2 with respect to the contact terminals 4 and 5.

Indeed, as illustrated in Figures 5 and 6, which represent the pusher 3 and the contact part 2 seen from below by compared to the previous figures, a rectangular slot 22 is cut in the central part of the contact piece 2 while a pin 23 of corresponding shape is provided at the end of pusher 3.

After engagement of the pin 23 in the slot 22, the tenon 23, for example using a high frequency vibrating tool, to secure the contact part 2 and the pusher 3, as illustrated in figure 7.

An anti-rotation link is also provided between the pusher 3 and the flexible blades, as visible in FIG. 1, in giving the pusher a section of substantially rectangular shape at the less in its connection part with the flexible blades which are provided with orifices 24 of corresponding shape.

Claims (6)

1. Switch device to open and close an electrical line, comprising two contact terminals, a control element comprising a contact piece able to be displaced axially between a closed position in which the contact piece rests simultaneously on both contact terminals, linking them electrically, and an open position in which the contact piece is distanced from the two contact terminals, and two parallel flexible blades permanently attached to the said control element (1), characterised in that the central part of each flexible blade (8, 9) is permanently attached to the control element (1) and that each end (8a, 9a) of each flexible blade (8, 9) is housed in a cradle (10a) of a support (10).
2. Device according to claim (1), characterised in that it comprises an actuator (17) with axial displacement acting on at least one flexible control blade (18), approximately perpendicular to the axis of displacement of the control element (1) and able to transmit to the latter the movements of the actuator (17).
3. Device according to any of claims 1 and 2, characterised in that it comprises an electrically conductive closure plate (7) and that the control element (1) comprises an electrically isolating pusher (3), the contact piece (2) of the control element (1) and the two contact terminals (4, 5) being situated on one side of the said closure plate (7), while the greater part of the pusher (3), the two flexible blades (8, 9) and the support (10) are situated on the other side of the closure plate (7).
4. Device according to claim 3, characterised in that the closure plate (7) comprises an orifice (7a) allowing the passage and axial displacement without friction of the pusher (3).
5. Device according to claim 4, characterised in that it comprises a means of sealing (16) between the pusher (3) and the closure plate (7).
6. Device according to any of claims 3 to 5, characterised in that in the open position of the control element (1), contact piece (2) rests on the closure plate (7).

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