EP0322986A1

EP0322986A1 - Switch, in particular for use as automatic switch

Info

Publication number: EP0322986A1
Application number: EP88203033A
Authority: EP
Inventors: Daniel Van 't Veen; Jan Bertus Wensink
Original assignee: Holec Systemen en Componenten BV
Current assignee: Eaton Holding International I BV; Danfoss Power Solutions II BV
Priority date: 1987-12-31
Filing date: 1988-12-28
Publication date: 1989-07-05
Anticipated expiration: 2008-12-28
Also published as: ATE88835T1; DE3880653D1; DK171090B1; DE3880653T2; DK732488D0; ES2040836T3; DK732488A; NO174177B; FI91199C; NO885823L; NO885823D0; NL8703172A; NO174177C; FI91199B; EP0322986B1; FI885996A

Abstract

A switch, in particular for use as automatic switch, comprising a housing (1) provided with at least one pair of contacts having a fixed (16) and a movable contact (14), and a leaf spring system having at least one arm (2) and leaf spring (6) which are hingedly coupled to each other at one end. One end of the arm/spring assembly thus formed being coupled to a body (8) supported in the housing (1) and movable relative to the fixed contact (16), said body (8) bearing the movable contact (14). The other end of the arm/spring assembly being fixedly positioned and hingedly supported (21) in the housing (1) at a distance from and opposite said fixed contact (16). The dimensions of the movable supported body are such that in the one position of the pair of contacts the at least one arm (2) and leaf spring lie in line with each other and the at least one leaf spring (6) is tensioned. In the other position the at least one arm (2) and leaf spring (6) assume a position which is deflected relative to the one position. For taking and locking the at least one pair of contacts into the one and/or the other position operating and locking means (22, 23, 40, 46) are provided.

Description

The invention relates to a switch, in particular for use as automatic switch, comprising a housing provided with at least one pair of contacts having a fixed and a movable contact, a leaf spring system having at least one arm and leaf spring which are hingedly coupled to each other at one end, one end of the arm/spring assembly thus formed being coupled to a body supported in the housing and movable relative to the fixed contact, said body bearing the movable contact, and operating means for taking the at least one pair of contacts into one and/or the other position under the effect of the action of the leaf spring system.
An electric switch comprising a leaf spring system of this type is known from French Patent Specification 2,057,181.
Switches for use as automatic switch are in practice used mainly as protection against overloading, short circuit and earth leakage currents in electrical energy distribution plants. Although these functions can be combined in one automatic switch, automatic switches which switch off only, for example, in response to earth leakage currents are also found in practice.
In the case of switching devices in automatic switches for interrupting short circuit currents high requirements are set for the design of the contact arrangement and the switching mechanism. A discharge arc occurring during the interruption of a short circuit current must be capable of being effectively extinguished and must not cause damage to the switch itself because, unlike the situation with, for example, fuses, automatic switches must be capable of being used several times.
In order to obtain a sufficiently high contact opening speed, a fairly complex spring system of draw and compression springs is generally used, which not only takes up a large amount of space, but also makes the assembly of this type of automatic switch complex. For example as in the embodiment according to French Patent Specification 866,592. Since it is generally necessary to be able to place several automatic switches alongside each other in an installation cabinet of an electrical plant, every effort is made in practice to keep the dimensions of such automatic switches as small as possible in practice, but this effort is limited by the requirement for effective extinguishing of a discharge arc and the construction of the spring system of the switching mechanism. The automatic switches presently used are fairly complex on account of their special design and construction.
In the case of automatic switches which are designed, for example, only for switching off earth leakage currents, the contact device must be designed in such a way that in the current-conducting state of the automatic switch sufficiently high contact pressure is exerted to prevent the contacts from being opened as a result of the forces exerted by a short circuit current. In order to be able to comply with this, the switching mechanism must be made relatively "heavy", it also being necessary for the contacts to be capable of being opened quickly during the occurrence of an earth leakage current. It will be clear that these requirements also have an adverse effect on a simple and reliable design of the automatic switch.
In contrast to spring systems having drawn and compression springs with switching arms and levers coupled to them, the use of leaf springs make it possible to build switches with a compact construction. Further, leaf springs are used for their relative high force acting in longitudinal direction, the so called bending force.
From structural viewpoint, the switch with leaf spring system according to said French Patent Specification 2,057,181 has the disadvantage in that the bending force by the leaf spring acts on four hinge points. In particular, the bending force acts directly to the control knob coupled with one end of the arm/leaf assembly. Due to the fact that for the use as automatic switch a relatively strong leaf spring is required, for instance to meet the desired switching speed, all the hinge points will be correspondingly heavily loaded and as a matter of fact all need special care.
The object of the invention is therefore to produce a switch with a switching mechanism comprising a leaf spring system, which is simple in design and compact in construction, is relatively simple and quick to produce and assemble, and with which in particular the requirements for use as an automatic switch can be met.
This is achieved according to the invention in that the other end of the arm/spring assembly being fixedly positioned and hingedly supported in the housing at a distance from and opposite said fixed contact, said movably supported body has such dimensions and is slidably supported in the direction to and from said fixed contact, that in the one position of the pair of contacts, in which the at least one arm and leaf spring practically lie in line with each other, the at least one leaf spring is tensioned, and in the other position of the pair of contacts the at least one arm and leaf spring assume a position which is deflected relative to the one position, and in that locking means are provided to act on the arm/spring assembly for locking the at least one pair of contacts in the one and/or the other position.
Through the mutual arrangement of the various parts of the switch according to the invention, the number of hinge points loaded by the bending force of the leaf spring is reduced to three, and by which a simple and compact construction is achieved.
In order to be able to move the at least one pair of contacts of the switch according to the invention into a particular position and lock it there by hand using a switch button, the preferred embodiment of the invention is characterized in that the switch button is hingedly mounted in the housing at a distance from and opposite the at least one arm and leaf spring in the direction of deflection thereof, in such a way that part of the switch button can project at the outside of the housing, while the locking means comprise an arm-shaped locking element, one end of which can act on the at least one arm of the leaf spring system, the other end being hingedly connected to the switch button in such a way that on operation thereof a force can be exerted on the leaf spring system for moving the body towards or away from the fixed contact, and in which the housing is provided with a first and second stop against which part of the switch button rests, in such a way that the at least one pair of contacts of the switch assumes the one or the other position.
The position of the switch button in the preferred embodiment of the invention opposite the at least one arm/spring assembly in the direction of deflection thereof has the advantage in that the at least one leaf spring can be tensioned by exerting a force in transverse direction of the arm/spring assembly, which force is small compared to the force for tensioning the leaf spring from one end thereof, i.e. in longitudinal direction of the leaf spring.
Particularly for use in electrical energy distribution plants, it is necessary from the point of view of safety to produce a visual indication of the position of the at least one pair of contacts on the outside of the housing of a switch. In the preferred embodiment of the switch according to the invention this is achieved in that the part of the switch button which can project outside the housing is oblong in shape, the first and second stop being formed by opposite walls of a recess disposed in the housing on the side where the switch button is accessible from the outside, in such a way that in the one position of the at least one pair of contacts the oblong part of the switch button is recessed in the periphery of the housing and is accessible from the outside of the housing via the recess and in the other position that part projects outside.
The position of the at least one pair of contacts can thus be deduced from whether or not the oblong part of the switch button is projecting outside. This embodiment has the further advantage that in the one position of the pair of contacts the oblong part of the switch button is situated entirely within the periphery of the housing, which means that inadvertent operation of the switch button, for example, is prevented.
In addition to manual operation of the contacts of the switch, it is of course necessary, for example when it is being used as an automatic switch, to be able to operate the contacts automatically when overload, short circuit and earth leakage current occurs. In another embodiment of the switch according to the invention this is achieved in that the operating means comprise an unlocking element set up in the housing and having mating therewith electrically, hydraulically, and/or pneumatically operable further means, said unlocking element being capable of acting on the locking element in such a way that when the at least one leaf spring is locked in its tensioned one position, the action of the locking element on the at least one arm of the leaf spring system under the influence of the action which can be exerted by the further means can be released, so that the arm/spring assembly assumes its other position, and means being provided for resetting the unlocking element. In order also in these cases to visualise the position of the contacts, the switch button can be moved, by means of a spring, for example, into the position in which the oblong part of the switch button projects outside.
An embodiment of the switch according to the invention is further characterized in that the unlocking element has a base part hingedly supported by two opposite side faces of the housing and having an arm part which extends in one direction at right angles to the direction of deflection of the arm/spring assembly, and which acts on the locking element, and one or more arm parts extending in the opposite direction, on which the further means can act for tilting the unlocking element about its hinge point.
In this unlocking construction, use is advantageously made of the fact that in the position in which the at least one arm and leaf spring are in line with each other the spring force acts virtually completely in the lengthwise direction of the arm and the leaf spring, and there is only a relatively small component of the spring force in the direction of the locking element. A relatively small force is consequently needed for moving of the locking element, so that a light unlocking construction and relatively simple further means for operation thereof are all that is needed. Another embodiment of the switch is further characterized in that the further means comprise at least one electromagnet with a movable armature, said armature acting on the unlocking element for the purpose of releasing the action of the locking element on the at least one arm of the leaf spring system under the influence of the force to be exerted thereby.
The means for resetting the unlocking element can according to the invention comprise spring means acting thereon or an oblong element connected to the movable element, the free end of said oblong element being capable of acting on the unlocking element.
During manual switching of the at least one pair of contacts, in order to make it possible to build up sufficient spring force before the pair of contacts is moved from one position to the other, yet another embodiment of the switch according to the invention is characterized in that the housing contains at least one angle lever which is disposed near the movable body hingeing about its bend point in such a way that it acts with one end on the body for retaining the body in the other position against the spring force of the at least one leaf spring, the at least one angle lever being capable of being rotated about its hinge point via its other end in such a way with the switch button that the action on the body is released and this body can be moved at a predetermined speed by the spring force of the at least one leaf spring acting thereon for moving the pair of contacts into the one position, and means being provided with which the at least one angle lever can act on the body again after the locking thereof has been released with the switch button. The said means preferably consist of spring means acting on the at least one angle lever.
With this design it is possible to fix the moment at which the element is set in motion, for example on closing of the contacts, so that in the case of a switch with several movable elements and thus several pairs of contacts the point of action of the at least one angle lever on the movable element can be selected in such a way that one or more elements can be set in motion at different moments, and a leading or lagging switching of the various pairs of contacts relative to each other can be achieved. It is possible in this way to meet the requirements of electricity companies that in automatic switches the zero contact should not be produced later than a phase contact.
The design of the leaf spring system is in that sense dependent on the requirements concerning the contact pressure and switching speed of the contacts, that for a higher contact pressure and higher switching speed the at least one leaf spring will have to possess a greater spring force. In order to reduce as much as possible the component of the spring force acting on the housing, the leaf spring system can have, in accordance with Netherlands Patent Application 8703173, filed by applicant simultaneously with the present patent application, a supporting frame in the frame aperture of which the at least one leaf spring and arm are supported.
According to another embodiment of the switch according to the invention, if the fixed contact is provided near an edge of the supporting frame in the frame aperture thereof, a partially so-called closed force leaf spring system is produced, it also being possible advantageously for the body bearing the movable contact of the at least one pair of contacts to be slidably supported in the frame aperture. In the case of lighter leaf spring systems the at least one arm and leaf spring and also the fixed contact can be fixed directly on the housing.
It will be clear that the arm, on the one hand, or the leaf spring, on the other, can be coupled to the body, so that the respective other end of the arm/spring assembly is hingedly supported. In the event of several movable bodies with switching contacts, several leaf springs each acting on one body can be coupled to one arm, but it is also possible to use, for example, a leaf spring made up of several strips, with several arms acting on a body. Of course, it is also possible to use several arms and leaf springs which act separately on a movable body. The connection between arm and leaf spring can be further achieved in a suitable manner.
An embodiment of the invention is further characterized in that the at least one arm of the leaf spring system is a rectangular wire bracket, over one leg of which a backward-bent end of the at least one leaf spring is disposed, the arm-shaped locking element being provided at its free end with a U- shaped notch by means of which it can engage with said leg of the wire bracket. Such a wire bracket permits easy assembly of the leaf spring system, for example, by means of snap connections.
Yet another embodiment of the invention is characterized in that the wire bracket is supported with its other end hinged in the housing, the other end of the at least one leaf spring being coupled to the movable body. This embodiment has the advantage that for switching several pairs of contacts, for example a phase and a zero contact, one common wire bracket and the operating, locking and unlocking elements acting thereon will be sufficient, while for the phased switching of the contacts, for example the zero contact first, only the element bearing the phase contact need be held by means of the angle lever mechanism and switched on with a predetermined force.
In order to permit electrical connection of the switch according to the invention, provision is made according to another embodiment for externally accessible connecting ends at one side of the housing. For rapid and simple fitting of the switch in, for example, the use as an automatic switch, yet another embodiment thereof is characterized in that the connecting ends are designed as plug-type connecting contacts which project outside the housing, in particular for connecting the switch in detachable fashion to a control panel by means of a plug connection. It goes without saying that the connecting ends can also be provided in the usual manner on, for example, terminals.
The invention will now be explained in greater detail with reference to two embodiments of an automatic switch according to the invention shown in the attached drawings.

Figs. 1a-d show schematically various cross sections of an embodiment of a switch according to the invention constructed as an automatic switch;
Figs. 2-5 show schematically in cross section and on an enlarged scale the switch according to Fig. 1, with various positions of the switching mechanism; and
Fig. 6 shows schematically in cross section another embodiment of a switch according to the invention.

Fig. 1a shows schematically a cross section of a switch according to the invention designed as an automatic switch, with a housing 1. The cross section shown in Fig. 1b through the line I-b-I-b in Fig. 1a shows the leaf spring system used in the automatic switch, comprising for example a rectangular wire bracket 2, whose one leg 3 is hingedly fixed by means of a snap connection to a foot 5 formed in the housing 1. From the other leg 4 of the wire bracket 2 extend two leaf springs 6, 7, which are each hingedly fastened, for example, with a backward-curved end also via a snap connection to the leg 4. It goes without saying that the connection between the wire bracket 2 and the leaf springs 6, 7 and the foot 5 can be achieved in suitable other ways, for example by using a U-shaped wire bracket in which the leaf springs and the foot are provided with fastening eyes for taking the legs of the wire bracket. The other end of each of the leaf springs 6, 7 is hingedly connected to bodies 8, 9 respectively. The bodies 8, 9 and the housing 1 are designed in such a way that the bodies 8, 9 are slidably supported in the housing. This is possible, for example by providing the bodies 8, 9 with guide rails 11 which fit in grooves 10 recessed in the housing. This is, however, also possible by providing the bodies 8, 9 with grooves 10 and the housing with guide rails 11. A pair of contacts 12, 13 is provided opposite the face on which the leaf spring acts on a body.
Each pair of contacts 12, 13 consists of a movable contact 14, 15 connected to the appropriate body and a contact 16, 17 fixed in the housing. In the position shown each pair of contacts 12, 13 is closed, which means that the respective contacts 14, 16 and 15, 17 are in contact with each other. The wire bracket 2 and the leaf springs 6, 7 are virtually in line with each other here, as can be seen in Fig. 1a, which shows a cross section of the leaf spring system along the line I-a-I-a in Fig. lb.
As can be seen in Fig. 1a, the top right corner of the housing 1 has provided in it an explosion chamber 18, in which guides 19, 20 connected to the respective contacts 14, 16 project, and which form a funnel facing the pair of contacts 12 for guiding a discharge arc occurring between the contacts 14, 16 during the closing or opening thereof. Suitable extinguishing means (not shown) can be accommodated in a known manner in the chamber 18. It will be clear that for the pair of contacts 13 a similar arc-extinguishing device to that for the pair of contacts 12 can be provided in the housing.
Since in a use of the switch according to the invention as an automatic switch in conjunction with a current-limiting switch, which is the subject of the Netherlands patent application 8703170, filed by applicant, only limited short circuit currents of the order of magnitude of about 100-500 A need be switched off, the explosion chamber can be relatively simple in design, and the design of the contacts themselves is not subject to such strict requirements. The force with which the respective contacts are pressed against each other, the contact force, must on the other hand be high, simply to be able to carry the unlimited short circuit current, which is achieved in the following manner.
The dimensions of the wire bracket 2 and the leaf springs 6, 7 with their respective bodies 8, 9 are such relative to the distance between the hinge point 21 of the wire bracket 2 at the foot 5 and the fixed contact 16, 17 that the leaf springs in the closed position of the contacts are tensioned, so that the largest component of the spring force acts in the lengthwise direction of the leaf spring and each movable body 8, 9 with its contact 14, 15 is pressed virtually with the full spring force of the leaf spring 6, 7 against the fixed contact 16, 17. The component of the spring force at right angles to the leaf spring surface is thereby very small by comparison with the force in the lengthwise direction thereof.
The leaf spring system can be locked in a simple manner in the position shown by means of the arm-type locking element 22, which is hingedly connected to the manually operable switch button 23. The locking element 22 has on its free end a U-shaped notch 24 which engages between the two leaf springs 6, 7 with the leg 4 of the wire bracket 2. The attachment point 25 of the arm-type locking element 22 on the switch button 23 is selected in such a way that in the position of the switch shown, through the component of the spring force at right angles to the leaf spring surface, an anticlockwise couple is exerted on the switch button 23, viewed in the plane of the drawing. Opposite the attachment point 25 of the locking element 22 the switch button 23 is provided with an oblong, curved projection 26 which rests against a stop 27 of the housing. In this way, via the locking element 22, the oblong projection 26 and the stop 27, the leaf spring system is locked in the position shown. The switch button 23 is connected to the housing so that it hinges about its centre point 28.
The stop 27 is formed by a raised part projecting in a recess 29 formed in the housing, in such a way that in the switched-on position of the automatic switch shown the projection 26 does not project outside the periphery of the housing 1 and is accessible by hand from the outside only via the part 30 of the recess 29 for operation of the switch button. Inadvertent operation of the switch button is effectively prevented in this way.
The housing also contains an angle lever 31 bent at right angles, which is accommodated in the housing near the body 8 and hinges about its bend point 32. The hooked end 34 of the arm part 33 of the angle lever 31 extending in the direction of deflection of the leaf spring in the housing acts on the locking element 22, at the level of the attachment point 25 thereof to the switch button 23. With the other hooked end 36 of the arm part 35 extending in the direction of movement of the body 8 at the side where a V-shaped notch 38 is disposed for attachment of the leaf spring 6 the angle lever can act on a stop 37 formed on the body 8. The working of said angle lever will be explained in greater detail further on in the description with reference to Figs. 2-5.
Fig. 1c shows a cross section of the automatic switch along the line I-c-I-c in Fig. 1a. It can be seen here that the switch button 23 extends from one side of the housing 1 to the other and is provided with lips 39 between which the locking element 22 is hingedly fastened and with its notch 24 engages with the leg 4 of the wire bracket 2. Viewed in the plane of the drawing, an unlocking element is provided under the wire bracket for releasing the lock of the wire bracket 2 and the leaf 6, 7 other than with the switch button 23. This unlocking element consists of an oblong base part 40 which is rotatably supported in the housing on the opposite walls thereof by means of bosses 41 projecting in the housing. The unlocking element has an arm part 42 extending in the direction of the locking element 22 and two arm parts 43, 44 extending in the opposite direction. The armatures of two electromagnets 45, 46 accommodated in the housing can act on the ends of said arm parts 43, 44 respectively, thereby permitting the unlocking element to be rotated about its support points. For the control of one or both of the electromagnets it is possible to accommodate, for example, a printed circuit board 54 provided with the necessary electronic components in the housing 1.
Instead of electromagnets, other suitable electrically, hydraulically or pneumatically operated means can act on the arm parts 43, 44 for automatically operating the unlocking element.
Fig. 1a shows the electromagnet 46 in side view, the action of the armature 48 on the arm part 44 of the unlocking element being clearly visible. The arm part 42 acts on a stop 49 attached to the locking element 22 at the side thereof facing away from the U-shaped notch 24, for example a pin projecting sideways from the locking element 22 in the direction of the arm part 42. The function and working of this unlocking element will be explained in greater detail further on in the description also with reference to Figs. 2 - 5.
At the bottom side of the housing 1, viewed in the plane of the drawing, there are also several strip-type connecting ends 50, projecting to the outside if necessary. These connecting ends 50 can be designed as required, for example, as plug-type connecting contacts such as plug pins for connecting the automatic switch with a plug connection to a control panel of an electric cabinet, but they can also be completed as connecting terminals, accommodated in the housing or attached to it on the outside, for connecting the automatic switch, for example, via a screw connection (not shown). At the one end not projecting outside, the connecting ends 50 are connected to the switch contacts in the switch and, for example, printed circuit board 54, for the sake of clarity the connection of the movable contact 14 not being shown in the cross section according to Fig. 1a. On the side of the housing where the connecting ends 50 project outside there is also a hook 52 by means of which the automatic switch can be locked via a snap connection to a control panel and can be moved via the groove 53 for the unlocking thereof.
Fig. 1d shows the view of the housing seen from the side where the connecting ends 50 and the hook 52 project outside. The working of the switch will now be explained with reference to Figs. 2 to 5, which show a cross section through the automatic switch according to Fig. la.
In the position of the automatic switch shown in Fig. 2 the contacts 14, 16 of the pair of contacts 12 are separated from each other and the leaf spring 6 is in its untensioned, unbent state. In order to ensure that the position of the switch button 23 always corresponds to the current position of the switch contacts, spring means can be disposed to act in such a way on the switch button that they exert a clockwise couple on the switch button, viewed in the plane of the drawing.
These spring means can in the known manner comprise, for example, a rotary spring disposed in the hinge point 28 of the switch button, or a helical leaf or wire spring, but also, for example a draw spring (not shown) acting on the attachment point 25 of the locking element 22. The force exerted by this spring on the switch button 23 must be such that the projection 26 thereof rests against the stop formed by the wall 56 of the recess 29.
The angle lever 31 is provided with spring means which cause the angle lever to rotate anticlockwise, viewed in the plane of the drawing, about its bend point 32. These spring means can also, for example, in the known manner consist of a rotary or coil spring (not shown) acting in the bend point 32 on the angle lever.
The rotation of the angle lever is limited through the fact that the arm part 35 acts on the movable body 8. The arm part 42 of the unlocking element at its end 55 is bent at such an angle in the direction away from the fixed contact 16 that in the deflected state of the leaf spring 6 shown the stop 49 of the locking element 22 can act on it. The projection 26 of the switch button 23 here projects out of the housing, which produces the visual representation that the automatic switch is in the switched-off state, i.e. in the state in which the contacts of the pair of contacts 12, 13 are separated from each other.
The automatic switch can then be switched on by moving the switch button 23 in the direction of the stop 27 by means of the projection 26 projecting outside the housing, thus anticlockwise viewed in the plane of the drawing. The locking element 22 is thereby moved in the direction indicated by the arrow 57, causing such force to be exerted on the leg 4 of the wire bracket 2 that the body 8 is moved in the direction of the fixed contact 16, until the stop 37 rests against the end 36 of the angle lever 31, so that the situation shown in Fig. 3 arises.
The leaf spring 6 is here virtually in its tensioned one position, in which the leaf spring and the wire bracket extend virtually in line with each other. The contacts 14, 16 are not in contact with each other here. The end 34 of the angle lever 31 here is against the end of the locking element 22 connected to the switch button 23. If the projection 26 of the switch button 23 is moved further towards the stop 27, the angle lever 31 is rotated clockwise, viewed in the plane of the drawing, about its bend point 32, causing the arm part 35 to be moved in the direction away from the body 8 and the action of the end 36 on the stop 37 of the body 8 to be released. Under the influence of the force exerted by the tensioned leaf spring 6, the body 8 is moved in the direction of the fixed contact 16, causing the contacts 14, 16 to be moved with force against each other and the automatic switch to be switched on, as shown in Fig. 1a.
It will be clear that the moment of switching on, i.e. the moment at which the contacts 14, 16 are moved against each other, can be influenced by varying the length of the ends 34, 36 of the angle lever and the position of the stop 37. Since the leaf spring 6 can be subjected to high bending stress, a required, high switching-on speed of the contacts of the automatic switch can be achieved, in the switched-on position the force with which the contacts are pressed against each other also being high. In the situation of a two-phase switch with a zero and a phase contact, it is possible, for example, to provide only the body with the phase contact with an angle lever acting thereon, so that the zero contact is switched on earlier than the phase contact, and thereby currentless. With the switch according to the invention it is thus possible to have either one or more pairs of contacts switched on unequally or one or more pairs of contacts switched on with a definite speed.
The automatic switch can then be switched off in two ways, i.e. the contacts of the pairs of contacts 12, 13 are separated from each other. If the projection 26 of the switch button 23 is moved by hand in the direction of the stop 56, such force is exerted by the locking element 22 on the leg 4 of the wire bracket 2 that, partly under the influence of the force of the leaf spring 6, the bracket and the leaf spring assume the deflected position shown in Fig. 2, and the contacts 14, 16 are separated from each other. Any discharge arc occurring between the contacts is guided between the contacts via the guides 19, 20 connected thereto, to the explosion chamber 18 and extinguished there in an effective manner.
Since the automatic switch must also be capable of switching off on the occurrence of overload, short circuit and earth leakage currents, the contacts can also be opened with the aid of the armatures of the electromagnets 45, 46 acting on the unlocking element, or with other suitable means. If the current through these magnets is sufficiently high, the armatures 47, 48 belonging to them are moved in the direction of the arm parts 43, 44 of the unlocking element, causing the unlocking element to be tilted about its support points, as shown in Fig. 4. Since the arm part 42 of the unlocking element acts on the stop 49 of the locking element 22, it is moved in the direction away from the fixed contact 16, thereby releasing the action on the leg 4 of the wire bracket 2. Under the influence of the force exerted by the spring action, the leaf spring 6 and the bracket 2 again assume their deflected position, as shown by the arrow 58, so that the contacts 14, 16 move into the position separated from each other, as shown in Fig. 5.
In order to move the arm part 42 of the unlocking element into the vertical position again, as for example shown in Fig. 2, use can also be made in the known manner of spring means acting thereon, such as a rotary or coil spring, if necessary in conjunction with one or more stops for limiting the travel of the arm part 42, said spring means having to exert a clockwise couple on the arm part 42, viewed in the plane of the drawing. Another way of returning the unlocking element is to fit at least one oblong, for example bar-shaped, element 59 on the projection 51 of the movable body 8, 9, as shown schematically by a dotted line in the drawing. This oblong element 59 can act with its free end on the arm part 44 or 43 of the unlocking element in such a way that when the contacts are open the arm part 42 goes into the abovementioned vertical position.
From the position shown in Fig. 5 the automatic switch can be switched on again, for example manually by the switch button 23 to the position shown in Fig. 2, causing the locking element 22 with its U-shaped notch 24 to engage with the leg 4 of the wire bracket. However, with the presence of spring means acting on the switch button 23, as discussed above, these spring means would ensure in the situation shown in Fig. 5 that, after the release of the locking of the locking element 22, the automatic switch goes by itself into the position shown in Fig. 2. From this position the automatic switch can be switched on again in the manner discussed above.
Fig. 6 shows schematically in cross section another embodiment of a switch according to the invention, with a leaf spring system comprising a supporting frame 60, a leaf spring 61 and the arm 62. The leaf spring 61 is fastened at one end to the supporting frame 60 and can be integral therewith as shown, or can be connected by means of a further element so that it hinges freely, as shown, for example, in Fig. 6a of the abovementioned Netherlands patent application 8703173, filed simultaneously by applicant. The free end of the leaf spring 61 is hingedly connected to one end of the arm 62, at the other end of which a body 63 (contact block) is hingedly connected. The body 63 bears a movable contact 64 and via a glider is slidably mounted in the frame aperture of the supporting frame 60 and is electrically connected to a terminal 65. The fixed contact 67 working together with the movable contact 64 is fixed in the frame aperture on the frame side situated opposite the fixed end of the leaf spring 61 and is electrically connected to the terminal 68.
As already explained in the above-mentioned Netherlands Patent Application 8703173, the supporting frame 60 has to be rigidly supported by the housing of the switch or by a separate chassis inside the housing (not shown). Said leaf spring system with supporting frame constitutes for virtually the most part a so-called closed force system, which means that the tension exerted by the leaf spring is largely absorbed by the combination of the spring, the body and the supporting frame. This means that much lower strength requirements are needed for the housing or the chassis in which such a leaf spring system is mounted.
If now, by means of the switch button 69 and the arm-type unlocking element 70 attached thereto, the leaf spring 61, which is in the deflected position relative to the plane of the support ing frame 60, and the arm 62 are moved in the direction of the supporting frame 60, the body 63 will be moved in the direction of the fixed contact 67 until the two contacts 64, 67 come into contact with each other. If the leaf spring 61 is now forced further towards the supporting frame 60, said leaf spring 61 will be tensioned further and will thereby exert a contact force on the closed contacts.
The locking of this position is obtained through the flat part 71 of the switch button 69 resting against the stop 72 formed in the housing and the unlocking element 70 in this position exerting a anti-clockwise couple on the switch button 69. The locking can be released again by manually moving the switch button 69 clockwise, viewed in the plane of the drawing, as a result of which the arm 62 is moved via the locking element 70 acting thereon to its deflected position relative to the supporting frame 60. The movement of the locking element 70 is fixed via a guide 73 acting in concert therewith. Although not shown, spring means acting on the switch button 69 for taking it against a stop are produced in a manner corresponding to that of the preceding embodiment. The arm 62 can be designed as a wire bracket.
It will be clear that in this embodiment of the switch according to the invention it is also possible, in a manner similar to that of the embodiment shown in Fig. 1, to provide a mechanism for switching off the switch, for example by means of an electromagnet, and also an angle lever mechanism to produce a phased switching-on of the contacts.
It will be clear that the switch according to the invention is not limited to the embodiment thereof shown and described, but that many variations and expansions can be produced by an expert, without departing from the scope and idea of the invention.

Claims

1. A switch, in particular for use as automatic switch, comprising a housing provided with at least one pair of contacts having a fixed and a movable contact, a leaf spring system having at least one arm and leaf spring which are hingedly coupled to each other at one end, one end of the arm/spring assembly thus formed being coupled to a body supported in the housing and movable relative to the fixed contact, said body bearing the movable contact, and operating means for taking the at least one pair of contacts into one and/or the other position under the effect of the action of the leaf spring system, characterized in that the other end of the arm/spring assembly being fixedly positioned and hingedly supported in the housing at a distance from and opposite said fixed contact, said movably supported body has such dimensions and is slidably supported in the direction to and from said fixed contact, such that in the one position of the pair of contacts, in which the at least one arm and leaf spring practically lie in line with each other, the at least one leaf spring is tensioned, and in the other position of the pair of contacts the at least one arm and leaf spring assume a position which is deflected relative to the one position, and in that locking means are provided to act on the arm/spring assembly for locking the at least one pair of contacts in the one and/or the other position.

2. A switch according to Claim 1, in which the operating means comprise a manually operable switch button, characterized in that the switch button is hingedly mounted in the housing at a distance from and opposite the at least one arm and leaf spring in the direction of deflection thereof, in such a way that part of the switch button can project at the outside of the housing, while the locking means comprise an arm-shaped locking element, one end of which can act on the at least one arm of the leaf spring system, the other end being hingedly connected to the switch button in such a way that on operation thereof a force can be exerted on the leaf spring system for moving the body towards or away from the fixed contact, and in which the housing is provided with a first and second stop against which part of the switch button rests, in such a way that the at least one pair of contacts of the switch assumes the one or the other position.

3. A switch according to Claim 2, characterized in that the part of the switch button which can project outside the housing is oblong in shape, the first and second stop being formed by opposite walls of a recess disposed in the housing on the side where the switch button can project outside, in such a way that in the one position of the at least one pair of contacts the oblong part of the switch button is recessed within the periphery of the housing and is accessible from the outside of the housing via the recess and in the other position that part projects outside.

4. A switch according to Claim 3, characterized in that spring means acting on the switch button are provided to move the switch button against a stop.

5. A switch according to Claim 2, 3 or 4, characterized in that the operating means comprise an unlocking element set up in the housing and having mating therewith electrically, hydraulically, and/or pneumatically operable further means, said unlocking element being capable of acting on the locking element in such a way that when the at least one leaf spring is locked in its tensioned one position, the action of the locking element on the at least one arm of the leaf spring system under the influence of the action which can be exerted by the further means can be released, so that the arm/spring assembly assumes its other position, and means being provided for resetting the unlocking element.

6. A switch according to Claim 5, characterized in that the unlocking element has a base part hingedly supported by two opposite side faces of the housing and having an arm part which extends in one direction at right angles to the direction of deflection of the arm/spring assembly, and which acts on the locking element, and one or more arm parts extending in the opposite direction, on which the further means can act for tilting the unlocking element about its hinge point.

7. A switch according to Claim 5 or 6, characterized in that the further means comprise at least one electromagnet with a movable armature, said armature acting on the unlocking element for the purpose of releasing the action of the locking element on the at least one arm of the leaf spring system under the influence of the force to be exerted thereby.

8. A switch according to Claim 5, 6 or 7, characterized in that the means for resetting the unlocking element comprise spring means acting thereon.

9. A switch according to Claim 5, 6 or 7, characterized in that the means for resetting the unlocking element comprise an oblong element connected to the movable body, the free end of said oblong element being capable of acting on the unlocking element.

10. A switch according to one or more of Claims 2 to 9, characterized in that the housing contains at least one angle lever which is disposed near the movable body hingeing about its bend point in such a way that it acts with one end on the body for retaining the body in the other position against the spring force of the at least one leaf spring, the at least one angle lever being capable of being rotated about its hinge point via its other end in such a way with the switch button that the action on the body is released and this body can be moved at a predetermined speed by the spring force of the at least one leaf spring acting thereon for moving the pair of contacts into the one position, and means being provided with which the at least one angle lever can act on the body again after the locking thereof has been released with the switch button.

11. A switch according to Claim 10, characterized in that the said means consist of spring means acting on the at least one angle lever.

12. A switch according to Claim 10 or 11, characterized in that the housing contains several movable bodies, on one or more of which an angle lever can act.

13. A switch according to one or more of Claims 2 to 12, characterized in that the at least one arm of the leaf spring system is a rectangular wire bracket, over one leg of which a backward bent end of the at least one leaf spring is disposed, the arm-shaped locking element being provided at its free end with a U-shaped notch by means of which it can engage with said leg of the wire bracket.

14. A switch according to Claim 13, characterized in that the wire bracket is supported with its other leg hinged in the housing, the other end of the at least one leaf spring being coupled to the movable body.

15. A switch according to Claim 14, characterized in that the wire bracket is attached to the housing by its other leg.

16. A switch according to one or more of Claims 1 to 13, characterized in that the leaf spring system comprises a supporting frame, near one edge of which the fixed contact of the at least one pair of contacts is disposed in the frame aperture, while on the opposite edge of the supporting frame an end of the arm/spring assembly is hingedly supported in the frame aperture.

17. A switch according to Claim 14, 15 or 16, characterized in that the movable body is block- shaped, with a V-shaped notch formed on one surface thereof, in which notch the backward-bent other end of the at least one leaf spring is hingedly fastened to the body, opposite which surface the movable contact of the at least one pair of contacts is situated, two opposite further surfaces of the body being provided with means for slidably supporting the body.

18. A switch according to Claim 17, characterized in tha the movable body is disposed in the frame aperture of the support ing frame, the said means comprising grooves and guide rails which engage with each other.

19. A switch according to Claim 17 or 18, characterized in that at the side of the body on which the leaf spring acts there is an extension with a stop on which the one end of the angle lever pointing in the direction of deflection of the arm/spring assembly acts, and the other end of which points in the direction of the hook-shaped locking element.

20. A switch according to one or more of Claims 13 to 19, characterized in that, on the side facing away from the notch, the locking element is provided with a stop, on which the unlocking element acts.

21. A switch according to Claim 20, characterized in that the unlocking element on the end of the arm part which acts on the locking element is bent slantingly in the direction away from the fixed contact in such a way that in the position in which the arm/spring assembly is deflected this slanting end acts on the stop of the locking element.

22. A switch according to one or more of the preceding claims, characterized in that at least one printed circuit board provided with electronic components is provided in the housing for feeding control signals to the operating means.

23. A switch according to one or more of the preceding claims, characterized in that externally accessible connecting ends for the electrical connection of the switch are disposed on one side of the housing.

24. A switch according to Claim 23, characterized in that the connecting ends are designed as plug-type connecting contacts which project outside the housing, in particular for connecting the switch in detachable fashion to a control panel by means of a plug connection.

25. A switch according to Claim 24, characterized in that a hook-shaped projection is provided on the side where the connecting ends project outside, for locking the switch on the control panel.