EP0670579A1 - Switching device for connecting and closing an electric line - Google Patents

Abstract

In the switch, the central part of each flexible strip (8,9) is fixed to the moving part (1) of the switch and each of the ends (8a,9a) of the strips is housed in the mount (10a) of a support (10). An operating mechanism (17) acts on a flexible control strip (18) lying perpendicular to the axial displacement of the operator so as to transmit the movements to the moving part. The moving part has a pushbutton (3) which is insulated from the contact piece (2). The flexible strips deflect to allow simultaneous connection of the two fixed contacts (4,5) by the contact piece. A closure plate (7) separates the contacts from the major part of the pushbutton.

Description

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

Switching devices are already known for opening and closing an electrical line in which a blade-shaped contact piece is supported by an actuator movable in translation between a position in which said contact piece is applied on two contact terminals by closing the power line, and a position in which it is spaced from said contact terminals by opening the power line.

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

However, such guidance has the drawback that the friction which is exerted between the contact piece and its guide rods produces dust which can deposit on the electrical contact surfaces and can, in the long run, degrade the reliability of the device. of commutation.

Document DE-A-2 417 280 discloses a switch for an electric typewriter keyboard key, in which the operating member carrying the contact piece is guided by two parallel flexible blades 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 relative to the axis of movement of the operating member, due to the length of the blades which must be sufficient for the latter to have elasticity. required.

Another problem inherent in this known switch stems from the fact that the flexible blades, which form a parallelogram, guide the operating member, not in a strictly axial direction, but in a movement of circular translation.

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

The present invention aims in particular to solve these problems.

The subject of the present invention is a switching device for opening and closing an electric line, comprising two contact terminals, an operating member comprising a contact part, capable of being moved axially between a closed position in which the contact part applies simultaneously to the two contact terminals by electrically connecting them and an open position in which the contact piece is spaced from the 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 operating member and that each of the ends of each flexible blade is housed in a cradle of a support.

According to the invention, the operating member is located in the central part of each flexible blade, that is to say in the part of the flexible blades where their amplitude of deformation is maximum along the axis of movement of the operating device.

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

Thus, it is possible to produce a switch whose overall surface area is substantially limited to a rectangle whose length corresponds substantially to the spacing of its two contact terminals and whose width corresponds substantially to that of the contact piece which connects the two contact terminals.

In this way, several switches according to the invention can be positioned side by side on the same printed circuit board.

In addition, the fact that, in accordance with the invention, the two flexible blades are housed at their ends in a cradle of a support, and not embedded, makes it possible to create a pivot connection between the support and the ends of the blades. This pivot link gives increased flexibility to the blades, without the latter having to have a significant length.

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

In a preferred embodiment of the invention, the operating member 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 member maneuver, and able to transmit to the latter the movements of the actuator.

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

In fact, if the actuator transmitted an axial displacement to the operating member over a stroke greater than the length which separates its open position and its closed position, it could result in deterioration of the maneuver or actuator.

Conversely, if the actuator transmitted a too small amplitude displacement to the operating member, this could result in poor application of the contact part on the contact terminals and an imperfect closing of the electric line.

Thanks to the presence of a flexible control blade between the actuator and the operating member, it is possible to deliberately use an actuator which has too great an axial clearance relative to the length which the operating member has to travel, so as to ensure that said operating member is moved over a sufficient length to ensure good electrical contact, while preserving the operating member and the actuator from 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 piece 2, electrically conductive, and a pusher 3, electrically insulating.

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

The contact piece 2 is able to be applied simultaneously to 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 electric line formed by the two contact terminals 4, 5 and the contact piece 2 is thus protected from any electromagnetic radiation outside the switching device.

According to the invention, the operating member 1 is integral with two parallel flexible blades 8 and 9, the general shape of which is visible in FIG. 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.

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

It is understood that by being thus supported by the blades 8 and 9, the pusher 3 can only move in an axial translational movement during which the flexible blades 8, 9 flex while remaining parallel to each other.

It also appears clearly, in particular in FIGS. 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 the pusher 3.

FIG. 2 shows the switching device in the open position of the operating member, the contact piece 2 being spaced from the contact terminals 4 and 5.

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

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

In this way, the flexible blades 8, 9 permanently exert on the 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 piece 2 which is thus suitably applied against the closure plate 7.

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

FIG. 4 shows 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 an open cylindrical sleeve 13.

The opening of the sleeve 13 must be large enough to allow engagement thereof, by a radial translational movement, on the upper part of the pusher 3.

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

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

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

Thus, not only does the switching device comprise no part which would be liable to generate 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 orifice 7 a .

An actuator 17, for example electromagnetic, is capable of moving along an axis parallel to that of the 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 in the vicinity of the free end of the pusher 3.

We understand that the control blade 18 is capable of transmitting to the pusher 3 the translational movements of the actuator 17 which are directed according to the arrow 20 indicated in Figure 3, to bring the operating member 1 in its closed position .

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 from it to allow the flexible, pre-cambered blades 8, to bring the operating member back 1 in its open position.

As already explained above, the presence of the control blade 18 makes it possible to use an actuator 17 whose axial movement is slightly too large compared to that of the operating member 1, which guarantees optimal contact between contact terminals 4, 5 and contact part 2.

In the embodiment which has just been described, it can be noted that the use of flexible blades makes it possible to orient the contact part 2 properly with respect to the contact terminals 4 and 5.

Indeed, as illustrated in FIGS. 5 and 6, which represent the pusher 3 and the contact piece 2 seen from below with respect 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 the pusher 3.

After engagement of the stud 23 in the slot 22, the stud 23 is crushed, for example using a high-frequency vibrating tool, to secure the contact piece 2 and the pusher 3, as illustrated in FIG. 7.

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

It is understood that the embodiments which have just been described have no limiting character and that they can receive any desirable modifications without departing from the scope of the invention.

Claims (6)

1 - Switching device for opening and closing an electric line, comprising two contact terminals, an operating member comprising a contact part, capable of being moved axially between a closed position in which the contact part is applied simultaneously to the two contact terminals by electrically connecting them and an open position in which the contact piece is separated from the two contact terminals, and two parallel flexible blades integral with said operating member (1), characterized in that the part central of each flexible blade (8, 9) is integral with the operating member (1) and that each of the ends (8 a , 9 a ) of each flexible blade (8, 9) is housed in a cradle (10 a ) of a support (10). 2 - Device according to claim 1, characterized in that it comprises an actuator (17) with axial displacement acting on at least one flexible control blade (18), substantially perpendicular to the axis of movement of the member of maneuver (1) and capable of transmitting to the latter the movements of the actuator (17). 3 - Device according to any one of claims 1 and 2, characterized in that it comprises an electrically conductive closure plate (7) and that the operating member (1) comprises an electrically insulating pusher (3), the contact piece (2) of the operating member (1), as well as the two contact terminals (4,5), located on one side of said closure plate (7), while most of of the pusher (3), as well as the two flexible blades (8,9 and the support (10) are located on the other side of the closure plate (7). 4 - Device according to claim 3, characterized in that the closure plate (7) has an orifice (7 a ) allowing passage and axial movement without friction of the pusher (3). 5 - Device according to claim 4, characterized in that it comprises a sealing means (16) between the pusher (3) and the closure plate (7). 6 - Device according to any one of claims 3 to 5, characterized in that in the open position of the member operation (1), the contact piece (2) rests on the closing plate (7).

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