EP0080687A1 - Rotary operated electric switch with automatic return in the case of voltage failure - Google Patents

Abstract

The switch comprises an electromagnet (9) with movable core (10) retracted in the presence of voltage to an arrangement of three levers (11, 12, 13) hooked together in pairs when the switch is activated; the first lever (11) is integral with the rotary operating axis (3), the second lever (12) rocks around a fixed central axis (23) under the respective actions of the released core (10) and a antagonistic spring (15), the third lever (13) rotating around an end axis (28) and provided with a return spring (16) ensures the maintenance of the operating axis (3) and of the first lever (11) by hooking with the other levers. The third lever which comprises a central locking notch (29) for the first lever, also comprises a transverse duct (24), provided with a notch (27), in which the free end (25) of the second lever is movable (12) which is itself provided with a hooking spout (26) cooperating with the notch (27) in the engaged position and allowing manual or automatic return to rest.

Description

The present invention relates to an electric switch, with rotary control, automatically recalled to rest in the absence of voltage.

Such a rotary electrical switch conventionally comprises a plurality of contacts arranged in groups, for example in pairs, on stepped wafers. Each of the contacts of a group includes a mobile element and a fixed element, the mobile element has its movement controlled by an operating axis common to the different wafers and generally located in their center. The operating axis is provided with cams arranged on each wafer stage so as to selectively control the movements of the movable elements of the contacts according to the rotation of the axis, under the action of a manual or servo-controlled command.

An automatic return device in the rest position is frequently added to these switches in the event of a significant drop in electrical voltage, for example to avoid inadvertent control of the electrical members controlled by the switch after a cut in the electrical current supplied to this switch.

Such a reminder device is described in particular in document FR-A 2 481 514. It plans to provide the operating axis with a restoring spring arranged concentrically and with a cam cooperating with two levers arranged so as to be sensitive to the position of the core of an electromagnet supplied under the tension that we want to monitor. When the electromagnet is normally supplied it is possible to position the operating axis in an engaged position ensuring the desired electrical switching and to maintain it there. When the electromagnet is not sufficiently supplied, the position of the core and its action on the levers triggers the return to the rest position of the operating axis by means of its return spring.

Such a device has the drawback of requiring the provision of a contact for energizing the electromagnet which must be closed at the start of the manual operation in order to allow hooking the levers and maintaining the engaged position. This switch-on contact actuated before the others complicates the switch and can lead to the addition of an additional wafer otherwise useless, for example in the case where four contacts are necessary for the control of the electrical component controlled and that each wafer is intended for two or four contacts.

The present invention therefore provides a rotary electrical switch with automatic return in the absence of voltage, which overcomes the drawbacks mentioned above insofar as it accepts being supplied with control voltage at any time during the maneuver. of engagement.

The rotary electrical switch according to the invention conventionally has an operating axis provided with a return spring at rest, with an electromagnet with a movable core, the release of which on the appearance of a loss of voltage triggers the recall and an arrangement of three levers hooked together in pairs when the switch is on. A first lever is secured to the operating axis, a second lever provided with a return spring rocks around a central fixed axis under the respective actions of the released core and an opposing spring. A third lever is rotatable around a fixed axis located at one of its ends and is provided with a return spring to ensure on the one hand the maintenance in the working position of the operating axis and the first lever by hooking with the other two levers and on the other hand the release of the first lever and the reminder when it is released by the second lever moved by the release of the core.

According to a characteristic of the invention, the first and second levers have their axes arranged on the same side of the third lever which has in its middle a locking notch for the first lever and at its free end a notched transverse duct in which the end of the second lever, which is furthest from the core, is movable, said end comprising a hooking spout located opposite and on the other side of this lever relative to the core, so as to hook the notch of the conduit when the core is retracted under the action of the electric voltage applied to the electromagnet and the axis of maneuver is placed in the latching position.

According to another characteristic of the invention, the notch of the transverse conduit is applied to the bearing face of the hooking spout at an obtuse angle favoring the stall and in that the return spring of the operating shaft produced a force on the second lever which prevents the stall in the absence of relaxation of the core, the three remaining levers hooked under the opposing actions of the return spring of the operating shaft and the return springs of the second and third levers.

According to another characteristic of the invention, the force of the return spring of the operating shaft, as applied to the second lever in the engaged position of the switch, is greater than that of the return spring of the second lever, so that the first lever emerges from the blocking notch of the third lever ', under the action of the return spring of the operating shaft, in the event of release of the hooking spout under the action of the released core.

Other characteristics and advantages of the invention will be mentioned in connection with the following description and with the figures listed below.

• FIG. 1 presents a perspective view of an example of a rotary electrical switch with return by lack of voltage to which the invention applies.
• FIG. 2 shows an elevation view of the housing of an example of a rotary switch contact plate to which the invention applies.
• Figures 3A to 3F show a block diagram of the return mechanism according to the invention at various stages of operation.
• Figure 4 shows a front view of a return mechanism according to the invention.
• Figure 5 shows an exploded perspective of a return mechanism according to the invention.
• FIG. 6 shows a variation of embodiment comprising an additional switching position compared to the embodiment shown in FIG. 4.

The example of a rotary switch presented in FIG. 1 conventionally comprises stepped pancakes 1, carrying connection terminals 2 connected to fixed contact elements which cooperate with other movable contact elements under the action of an axis of maneuver 3 to ensure the establishment and / or cutting of electrical connections depending on the position of the operating axis 3.

This operating axis 3 crossing the wafers 1 at their center, also passes through a housing 4 which contains a mechanism for ensuring the automatic return to the rest position, of said axis and of the contacts which it controls, in the event of a voltage drop.

FIG. 2 presents a top view of a wafer 1 showing the position of the connection terminals 2, of the operating axis 3 of the fixed 5 and mobile 6 elements of the contacts. In the example chosen, four connection terminals 2a, 2b, 2c, 2d are connected to as many fixed contact elements 5a, 5b, 5e, 5d which are capable of being connected two by two via elements. mobile 6a-6b, 6c-6d controlled two by two by control pistons 7ab and 7cd.

Each piston 7 comprises a pair of movable contacts per element, such as 6a and 6b for the piston 7ab, which move with the latter under the action of a cam 8 driven in rotation by the operating axis 3.

This operating axis 3 is provided with a handle or a servo-control not shown so that it can be operated from the outside of the switch, it also passes through the housing containing the automatic return mechanism in the rest position.

This box and its mechanism are symbolized at various stages of operation in FIGS. 3A to 3F and are specified in FIGS. 4 and 5.

The mechanism uses an electromagnet 9 with a movable core 10, a release arrangement with three levers 11, 12, 13 each provided with return springs 14, 15, 16; there is also shown a control handle 17 presented above the housing in Figures 3, this handle being secured to the top of the operating shaft 3 in the case of a manually controlled switch.

The supply of the electromagnet 9 under an electric voltage sufficient causes the movable core 10 to retract inside the electromagnet as shown in Figures 3D to 3F. The drop in tension below this sufficient level results in the relaxation of the core 10 under the action of an invisible return spring, and the end of the core pushes the end 18 of the lever 12 placed roughly perpendicular to the axis of movement of the core 10.

On the other hand when the core 10 is retracted, the end 18 of the lever 12 is no longer supported on the core 10 due to its interaction with the lever 13 and despite the action of the return spring 15 which is supported on the neighboring wall of the housing 4 to push it back towards this core 10.

The control axis 3 is provided with a lever 11, called the first lever, which is subject to it so as to rotate with it, this axis comprises a concentric return spring 14 which tends to bring it back from the control position such that shown in 3D to the rest position shown in 3A or possibly 3E.

This spring 14 is conventionally supported on a fixed point of the housing symbolized by the arrow 19 and on a cleat 20 secured to the lever 11, two stops symbolized by the arrows 21 and 22 limit the stroke of the lever 11 and therefore the rotation of the operating axis 3, for example at a quarter turn.

The lever 12, said second lever rocks around a fixed axis 23 which is disposed on the same side of the lever 13 as the operating axis 3, this fixed axis 23 is placed in the central zone of the lever 12 so as to provide two uneven arms, it switches between two fixed positions under the respective actions of the core 10 in the relaxed position and the opposing spring 15. These two fixed positions are limited by the dimensions of a notched transverse conduit 24 formed at the free end of the third lever 13, situated approximately parallel to the axis of movement of the movable core 10. For this purpose the end of the second lever 12 penetrates inside the transverse conduit 24 in which it has a certain mobility in the plane of FIGS. 3, that is to say perpendicular to the axis 23.

A hooking spout 26 is formed opposite and on the other side of the second lever 12 relative to the core 10, this hooking spout 26 and capable of cooperating with a notch 27 of the transverse conduit 24 so as to keep the levers 12 and 13 hooked together under certain conditions defined below.

The lever 13 is capable of oscillating around a fixed axis 28 placed at its end opposite to that which comprises the transverse conduit 24, this axis is disposed beyond the axis 3 so as to allow the lever 11 to be blocked in engaged position (1) of the operating axis 3 by means of a locking notch 29 formed in the middle of said lever 13 facing said operating axis 3.

In the example chosen, a roller 30 carried by the cleat 20 of the lever 11 comes to bear on the locking notch 29 when the operating pin 3 is in the engaged position. The return spring 16 returns the lever 13 to the rest position by resting on a wall of the housing 4.

In the rest position (0) of the operating axis 3 and in the absence of tension, the first lever 11 is in abutment on the stop 21, the core 10 is in the released position and pushes the end 18 of the second lever 12, the end 25 of this lever 12 comes to bear by its wall opposite the spout 26, against the part of the transverse conduit 24 which is closest to the axis 28 (fig.3A). If the operating axis is rotated clockwise, the roller 30 of the first lever 11 raises the notch 29 (fig.3B) and therefore the lever 13 which rotates around its axis 28 by crushing the spring 16, the second lever 12 remains stationary.

When the rotation of the operating axis 3 is complete (fig. 3C) the lever 13 is pushed back towards the operating axis 3 by the spring 16 and is applied to the roller 30, the second lever 12 remains stationary in the position defined by the released core 10.

When the operating handle is released, the return spring 14 of the operating axis 3 pushes the third lever 13 despite the action of the spring 16.

Indeed, it is arranged so that the component of the forces applied by the spring 14 and by the spring 16 on the lever 13 causes it to be lifted and the first lever 13 to be released if the two levers 12 and 13 are not hooked together.

On the other hand, if it is assumed that the electromagnet 9 is supplied via one of the contacts of the switch, for example on the or one of the supply phases, as soon as the contacts are established, after complete rotation of the operating shaft 3, the core 10 is retracted (fig.3D) the lever 12 is pushed back by the spring 15 and the hooking spout 26 engages with the notch 27 of the transverse conduit 25.

In the example envisaged, the notch 27 of the transverse duct is applied to the bearing face of the hooking spout 26 at an obtuse angle favoring the stall.

The opposing actions of the maneuvering axis return spring 14 and the springs 15 and 16 of the levers keep the three levers hooked two by two. A twist of the operating axis manually or by servo-mechanism makes it possible to return to the rest position (0) by making the action of the first lever 11 preponderant and by destroying the balance otherwise established. The notch 27 slides on the wall of the hooking spout 26 and the lever 13 rotates by crushing the spring 16, the roller 30 is released and returns to the rest position (fig.3F). The rotation of the operating axis 3 opens the contacts and cuts off the supply of the electromagnet 9, the core 10 of which is released. In the event of a serious cut or drop in the voltage supplying the electromagnet 9, taken here downstream of the switch contacts, and while the switch is normally engaged the core 10 is released and it pushes the end 18 of the lever 12 which separates the hooking beak 26 from the notch 27. The withdrawal of the hooking beak 26 towards the axis 28 of the lever 13 releases the latter which is lifted by the action of the lever 11, the axis 3 returning in the rest position cuts the power supply to the electromagnet 9 whose core 10 is released, the switch is found in the position of FIG. 3A.

Alternatively, it is also possible to provide the electromagnet 9 with a voltage not controlled by contacts of the switch.

In this case if the electromagnet 9 is supplied while the axis of maneuver 3 is in position (0) of rest, the core 10 is retracted (fig.3E) and the two levers 12 and 13 are hooked, possibly below the hooking spout 26. During the rotation of the axis of operation 3 from the rest position (0) to the engaged position the force applied via the roller 30 of the lever. It allows the notch 27 to slide on the bearing face of the hooking spout 26, which allows the lever 13 to be raised.

After passage of the notch 29 by the roller 30, the lever 13 approaches the operating axis 3 under the action of the spring 16, (fig.3F), at the end of the race the notch 27 and the hooking spout 26 again engage one in the other and the assembly is found in the position presented in the figure (3D).

The exploded view of FIG. 4 shows diagrammatically the positioning of the elements of the mechanism internal to the housing and in particular the three levers 11, 12, 13, the electromagnet 9 and its core 10 as well as the springs 14, 15, 16.

The return spring 14 concentric with the operating axis 3 of the switch is supported on a stop 19 of the housing and on the cleat 20 of the lever 11. The lever 11 is here composed of two distinct parts 11A and 11B, the part 11A comes plug into the cleat 20 to allow it to withstand the mechanical stresses imposed on it by the return spring 14.

The roller 30 carried by the cleat 20 is housed under the locking notch 29 between this notch and the end of the lever 13 which comprises the transverse duct 24 containing the end 25 of the lever 12.

The axis 28 of the lever 13 is not shown, it is an integral part of the housing as are the bearings of the axis 23, and the bearings of the axis 3 at the level of the parts 11A and 11B of the lever 11.

Similarly the springs 15 and 16 bear on the walls of the housing, the latter not being shown in this figure for reasons of clarity.

The variant shown in FIG. 6 corresponds to an electrical switch, with rotary control, automatically recalled when at rest in the absence of voltage, which has three switching positions, ie an additional position relative to the real sation mentioned before. This is to obtain two control positions in addition to the rest position to which the switch is returned in the absence of voltage regardless of the control position established at the time when the supply voltage of the electro- magnet, here referenced 9A, disappears.

According to the present variant, the return mechanism elements presented in FIG. 6 are practically identical to those presented in FIG. 4, with the exception of the third lever here referenced 13A, the various elements common to the two figures being assigned an index A on the Figure 6. The lever 13A has an additional locking notch 31 disposed between the central locking notch 29A and the end axis 28A around which the lever 13A rotates.

The additional locking notch 31 is of course placed on the same side of the third lever 13A as the median locking notch 29A so as to cooperate with the roller 30A of the first lever 11A in the same way as this median locking notch.

Consequently from the rest position in the absence of tension, the rotation of the operating axis 3A causes the lever 13A to be raised by the action of the roller 20A on the additional locking notch 31 then the return to the position of this last under the action of the spring 16A with attachment of the second lever 12A in the third lever 13A, if the movable core 10A of the electromagnet 9A is in the retracted position due to the presence of a sufficient electrical supply voltage electromagnet. If the rotation of the operating axis 3A is not continued, a first stable control position of the switch is obtained and maintained as long as the electromagnet 9A is suitably supplied and the operating axis 3A is not manipulated. If the rotation of the operating axis 3A is continued in the control direction, the roller 20A again raises the third lever 13A by acting on the central locking notch 29A. After the roller 20A has passed beyond this notch 29A, a second stable position for controlling the switch is then obtained in the manner previously mentioned by such a notch 29.

In the event of a voltage drop below a predetermined minimum value, regardless of the control position occupied by the switch, the release of the core 10A results in the release of the third lever 13A by unhooking the second lever 12A and the return of the first lever 11A in the rest position under the action of the spring 14A in the manner already mentioned above.

In known manner, each control position corresponds to a selective actuation different from the switch contacts.

Claims (5)

1 / Electric switch with rotary control automatically recalled at rest in the absence of voltage, comprising for this purpose an operating pin (3) provided with a return spring (14) at rest, an electromagnet (9) to movable core (10), the release of which at the loss of tension triggers the return, and an arrangement of three levers (11, 12, 13) hooked together in pairs when the switch is engaged, a first lever (11) being integral with the operating axis (3), a second lever (12) rocking around a central fixed axis (23) under the respective actions of the released core (10) and an opposing spring (15), a third lever (13) rotatable around a fixed end axis (28) and provided with a return spring (16), to ensure on the one hand the maintenance in the working position of the operating axis (3) and of the first lever (11) by hooking with the other levers (12, 13) and on the other hand the release of the first lever (11) and the return when it is released by the second lever (12) moved by the release of the core (10) said switch being characterized in that the first and second levers (11 and 12) have their axes (3 and 23) arranged on the same side of the third lever (13) which has in its middle a locking notch (29) for the first lever (11) and at its free end a notched transverse duct (24) in which is movable the end (25) of the second lever (12) which is the most remote from the core (10), said end comprising a hooking beak (26) situated opposite and on the other side of this second lever (12) relative to the core (10), so as to hook the notch (27) of the notched duct (24) when the core (10) is retracted under the action of the electric voltage applied to the electromagnet (9) and when the operating pin (3) is placed in position d 'engagement (1). 2 / electrical switch according to claim 1, characterized in that the notch (27) of the transverse conduit is applied to the bearing face of the latching spout (26) at an obtuse angle favoring the stall and in that the return spring (14) of the operating shaft (3) produces, in combination with the spring (15) of the second lever (12), a return force which prevents the release in the absence of release of core 10. 3 / electrical switch according to claim 2, characterized in that the force of the return spring (14) of the operating shaft (3) is greater than that of the spring (16) of the third lever (13) so that the first lever (11) emerges from the locking notch (29) of the third lever (13) under the action of the return spring (14) of the operating pin, in the event of release of the hooking spout (26) under the action of the nucleus (10) released. 4 / electrical switch according to claim 2, characterized in that the controlled rotation of the operating shaft (3) against the return spring (14), when the core (10) is retracted, causes the sliding of the notch (27) on the bearing face of the hooking spout (26) and the lifting of the third lever (13) allowing the passage of the first lever (11) beyond the locking notch (29) of the third lever then a new hooking of the spout (26) of the second lever with the notch (27) of the transverse conduit (24) and the engagement of the switch under safety conditions identical to those presented by a switch with prior contact for energizing electro -magnet. 5 / electrical switch according to claim 1, characterized in that the third lever (13A) comprises an additional locking notch (31) in addition to the locking notch (29A) disposed in the middle, said additional notch (31) being located between the locking notch (29A) and the end axis (28A) around which the third lever rotates.

Images