IE51194B1 - Interlocking equipment for electrical switches - Google Patents

Abstract

A removable casing 12'' containing at least two latches 13', 21' coupled to respective movable elements (e.g.- 11) of spaced apparatuses has at least one of the movable elements 11 mechanically associated with one of the latches 21 by a flexible transmission 30, 33. The latches 13, 21 are arranged with respect to each other so that if one is moved to a working position the other remains in a rest position and cannot be moved to a working position.

Description

It is known to provide a device for the locking of movements of at least two movable elements disposed respectively in two independent and spaced electrical apparatuses, this device comprising in a removable 5 housing a first movable latch coupled to the movement of a first movable element and a second movable latch coupled to the movement of a second movable element, these latches being disposed one with respect to the other in such a manner that at least when the first 1° latch is in a first working position the second latch cannot move and remains in a second rest position, and that when the second latch is in a second working position, the first latch cannot move and remains in a first rest position.

The known device, particularly when concerned with the reciprocal interlocking of at least two contactors, comprises two yoke devices intended each to engage directly on an identical movable element of each contactor, because most often the contactors concerned 20 are of the same model; in certain constructions, the casing of the device is kept clamped between two adjacent contactors.

In other known constructions, the two contactors to be locked are fixed on a common support receiving the latches, which are themselves coupled by connecting elements to the movable elements of the contactors.

All of these known constructions are based on a consideration that these two contactors are adjacent to each other and are of the same model.

However, when the apparatuses to be interlocked, and in particular contactors, are not of the same model, or when two identical contactors must be relatively distant for functional reasons, such as facility of making connections, or more than two contactors must observe, one with respect to the other, particular interlocking conditions, the solutions proposed hitherto are not capable of responding to these situations. It is naturally the same if the three situations mentioned above are found in combination.

The invention accordingly proposes to provide an interlocking equipment which first of all can be made use of when two contactors are so distant that a mechanical and rigid connection between them is practice ally impossible.

This utilisation will accordingly permit the installer to have a wide freedom of relative positioning which will result either in a respective disposition of the apparatuses which will correspond in a more logical manner to their functions, or in a diminution of the length of the conductors terminating at these apparatuses, SI 194 or again in the possibility of putting into operation interlocking operations between apparatuses already installed and apparatuses subsequently installed; in the case where the equipment would be applied to two contactors one of which would be of high rating for the feeding of a heavy load, whilst the other smaller one would be intended for auxiliary functions, a supplementary benefit would result not only from the economy permitted in support plates or chassis, because these latter must be dimensioned to receive the larger apparatus, but also from the mechanical isolation established between the two apparatuses wherein the lighter one would not be submitted to the shocks developed by the heavier one.

It has already been proposed to have, and use is still made of, electrical interlocking means which, permit the obtaining of part of the advantages mentioned, but for reasons of reliability very frequently electrical interlocking means are doubled up with mechanical interlocking means, notably for preventing the effects of any shocks on the apparatuses or on the installation of which they form part.

According to a first aspect of the invention, there is provided an interlocking equipment for effecting mutual interlockings in groups of electrical switches which are removably mounted on a chassis and each have movable contacts and a movable member which is displaceable simultaneously with the contacts from a work position to a rest position, said interlocking equipment comprising: a casing for removably mounting in proximity to a first electrical switch in a group and at a distance from a second electrical switch; first and second movable latches mounted in said casing for displacement from a rest to a working position, the said latches each having a coupling region and a latching region and being disposed one with respect to the other in such a manner that, when either one of the latches is in its working position, the latching region thereof prevents displacement of the latching region of the other latch to the working position thereof; first and second openings in the said casing, the first opening serving when in use for passage therethrough of the movable member of the first switch for direct engagement with the coupling region of the first latch; a flexible transmission means having a sheath and a cable movably mounted in said sheath, the sheath having a first end mounted on the casing with the cable passing through the second opening and being attached to the coupling region of the second latch, the sheath further having a second end; a catching member, having a channel opening into a recess, removably mounted on the second switch; and a locking member displaceable within said recess and removable from said recess, said locking member being positioned when in use for direct engagement with the movable member of the second switch, the second end of the sheath being mounted on said catching member with the cable passing through the channel and being removably attached to the said locking member.

According to a second aspect of the invention there is provided an interlocking equipment for effecting mutual interlockings in a group of electrical switches which are movably mounted on a chassis and each have movable contacts and a movable member which is displaceable simultaneously with the contacts from a work position to a rest position, said interlocking equipment comprising: a casing for removably mounting at a distance from first and second electrical switches in a group; first and second movable latches mounted in said casing for displacement from a rest to a working position, the said latches each having a coupling region and a latching region, and being disposed one with respect to the other in such a manner that, when either one of the latches is in its working position, the latching region thereof prevents displacement of the latching region of the other latch to the working position thereof; first and second openings in said casing; first and second transmission means each having a sheath and a cable movably mounted in said sheath, the first and second sheaths having respective first ends mounted on the casing with the first and second cables respectively passing through the first a'nd second openings and being attached to the respective coupling regions of the first and second latches, the sheaths further having a second end; first and second catching members, each having a channel opening into a recess, for removably mounting on the first and second switches respectively; and first and second locking members displaceable within said recess of the first and second catching members respectively and removable from said catching members, said locking members being positioned when in use for direct engagement with the movable members of the first and second switches respectively, the second ends of the first and second sheaths being mounted on the respective first and second catching members with the respective cable passing through the respective channel and being removably attached to the respective locking member.

There are already known devices for control at a distance making use of flexible couplings contained, or not, in a sheath, but the fields of use to which they are adapted makes them generally selected when large forces must be transmitted; when the known devices of such nature have been used for signalling purposes, or must transmit relatively small forces, it is not generally wished to dispose on the path of the mechanical signal a supplementary logic or mechanical function, at least if the amplitude of the movement of entry is such that a simple reduction of this movement is necessary at the outlet; the nature of the transformation of these two latter movements, which most often require an irreversibility of the transmission in one of the two directions, nevertheless excludes the carrying out of a logic function, such as a function of inhibition corresponding to a reciprocal interlocking between a first entry signal and a second entry signal.

There are likewise known reciprocal interlocking constructions utilising a flexible coupling between two electrical elements which are placed at a certain distance one from the other, and are generally operated by hand; in this known construction, use is not made of a separate casing having a particular function, the two ends of the coupling being directly coupled to interlocking elements mounted in a permanent manner on the elements of electrical apparatuses disposed at the interior of a ring.

Finally, the invention serves to provide an electrical installation in which, by reason of the equipment according to the invention, it will be possible to dispose, group or separate electrical apparatuses in such a manner that, on the one hand, a mechanical isolation is established between apparatuses of different ratings and that, on the other hand, a rational distribution of the functions of these apparatuses can be obtained.

The invention will be better understood from reading of the following description with reference to the accompanying drawings, wherein:Figs. 1, 3 and 4 show different installations making use of the equipment according to the invention adapted to interlock two apparatuses; Fig. 2 shows a first equipment adapted to be used in the installations according to Figs. 1 and 3; Figs. 4 and 5 show two variant equipments adapted to be used in the installations according to Fig. 4; Fig. 7 shows an interlocking equipment in which a flexible torsion transmission is used for its coupling to at least one apparatus to be interlocked; Fig. 8 shows a detail of construction relating to coupling means between a flexible connector and a latch contained in the casing of an equipment; Fig. 9 shows an installation in which there is effected an interlocking relating to more than two apparatuses; Fig. 10 shows in section the disposition of several latches such as those of Figs. 2 and β, for the purpose of carrying out interlocking operations of the installation of Fig. 9; Fig. 11 shows a first manner of construction of an interlocking device carrying out supplementary logic operations by mechanical means; Figs. 12 & 13 show in partially sectioned plan view and in elevation, a second manner of construction of an interlocking device having the same functions as that of the preceding figure.

Figs. 15 & 16 show supplementary features conferring on the apparatuses of Figs. 13 & 14 properties of reciprocity in the interlocking effects.

An electrical equipment or installation 1, seen in Fig. 1, comprises for example a series of plates 2,3, 4,5 mounted horizontally one adjacent another on two vertical uprights 6,7. On the plates 2 & 5 which are farthest apart there are disposed respectively two electrical apparatuses such as contactors 8 & 9; it will be supposed that in this case the two contactors are identical, and each comprise an internal or external movable element such as 10 or 11, which is associated with the movements of the contacts themselves, controlled by the energising of an electromagnet; this movable element can be for example the contact carrier, a finger, or a groove of the latter.

The distance which separates these two contactors results for example from the fact that the plates 2 or 3, 4, are occupied by other apparatuses 39 or 38, or that one of the contactors, for example 9, has been installed subsequently to the delivery of the equipment.

A casing 12, an example of the construction of which is seen in Fig. 2, contains a first latch 13, Π constituted by a first lever axis 15 and having a movable extremity 17, and a coupling coupling means such as pivoting about a fixed arm 16 terminated by an arm 18 provided with first 5119 4 an opening 19 which are accessible and movable across an opening 20 of the casing; a second latch 21, constituted by a second lever 22 pivoting about a fixed axis 23 and having a movable arm 24 terminated by an extremity 25, and a coupling arm 26 provided with second coupling means 27 accessible through an opening 28 of the casing.

The extremities 17 and 25 are placed adjacent to each other when the two levers are in their rest position (R13, R21) shown in this Figure; these levers cannot pivot independently one from the other because of the respective positions of their axes and of their extremities, because if one of the levers takes up a working position such as T13 illustrated in chain-dotted line, the other can only remain in its rest position R21, and inversely.

Consequently, if the two coupling means are coupled mechanically and respectively to the movable elements of two contactors, in suitable manner, only one of these contactors will be able to assume a working position, the other only being able to remain in a state of rest. In the vicinity of the opening 28 of the casing 12, or in the latter, there is fixed a first end 29 of a flexible sheath 30 having a second end 31, this latter having engaging means 32 adapted to be associated with an apparatus 9. A cable 33 is placed in this sheath in such a manner as to be able to slide freely therein and comprises a first end 34 and a second end 35, the first end being fixed to the coupling means 27 of the arm 26 of the lever 22, whilst the second end 35 is fixed for example to a slide 18* which is movable in 32 and comprises for example a coupling recess 19' adapted to cooperate with the movable element 11.

By referring to Fig. 1, it will be seen that the casing 12 is placed in the vicinity of the contactor 8 and moreover in such a manner that, the removable casing 12 being fixed either directly on the body 37 of the contactor 8 or in its immediate vicinity on the plate 2, the movable element 10 is associated at 19, see also Fig. 2; the engagement means 32 are themselves associated with the body 36 of the contactor 9 to couple 11 and 19*· When the contactor 9 is energised and assumes its ' working position, the movable element 11 exerts a traction on the cable 33 which transmits its movement to the second latch in order to impart to it a position T21, and as a result the contactor 8 cannot assume its working position by reason of the impossibility of pivoting of the first latch 13 which remains in position R13.

When the contactor 8 is energised before the contactor 9 and when a movement of the movable element 11 of the contactor 9 is caused by an internal electromagnet, this movable element cannot move because the latch 22 cannot pivot, by reason of the application of the end 25 on the end 17, and the cable 33 becomes submitted to a non-resilient tension which prevents any displacement of its second end 35.

The flexibility of the sheath and of the cable,which constitute a flexible transmission, permits them to be situated easily between the apparatuses 38 eventually placed between the contactors 8 and 9, this sheath and this cable constituting the flexible transmission indicated by the reference numeral 30'.

In the example of installation 1' shown in Fig. 3, the contactor 9' is of a rating and size greater than that of the contactor 8', and furthermore the path of the sheath 30' has bends in it; in this latter case it is more judicious to place a casing 12' equivalent to that described at 12 in the vicinity of the contactor 8' of lesser rating, and the engagement means 32* in the vicinity of the contactor 9' in order that the frictional forces appearing in the course of displacement of the cable 33' in the sheath shall be easily overcome by the contactor having a more powerful electromagnet.

Nevertheless, it is likewise possible to construct an installation 1 having a reciprocal locking device between two contactors 8” and 9, see Fig. 4, comprising a casing 12 receiving latches analogous to the latches 13, 21, referred to above coupled by two flexible transmissions 39, 40 and two engagement means 41, 42 particular to each movable element 32, 44 of the contactors (see also Fig. 5).

This manner of construction permits to share between the two contactors the frictional forces to be overcome when the distance which separates them is too large for the electromagnet of one of them to be able to undergo without Inconvenience the frictions developed in a single transmission of great length such as that shown in Fig. 1.

It is likewise possible to construct in an obvious manner apparatuses, similar to those which have just been described, with the aid of flexible transmissions 39', 40' comprising flexible cables and sheaths adapted to transmit forces of compression to produce the movement of the latches 13, 21 placed in a casing 12', see Fig. 6; these cables are however much more burdensome, which makes traction cables preferable. If necessary, it is likewise possible to envisage the use of flexible cables and sheaths 39, 40 adapted to transmit a rotary couple towards and away from a locking device 12', as has been shown in Fig. 7. However, the forces to be transmitted in this manner produce supplementary flexings and frictions which are less suitable for carrying out the function than the preceding solutions. In these Figs. 6 and 7, the elements having the same functions have the same reference numerals as those of Fig. 5, but accompanied by supplementary indices (*),(),(') and ().

The coupling means between the first ends of the cable and the latches, or between the second ends and the movable elements of the apparatuses to be locked, can make use of known means to permit the adjustment of the length of the cable as a function of the position of the latches and of the position of the movable elements; preference will be given to means which confer on this coupling a good reliability to withstand the large number of operations to 5119 4 which the apparatus may be subjected, for example by causing the working by flexing of the portion 46 of an end 47 of a flexible cable 53 which is assured by means of a screw 48 placed at the end of a curved surface 49 of the latch 53 on which this end is rolled, as can be seen in Fig. 8, wherein the coupling arm 26 of Fig. 2 is here represented by a cylindrical surface 50 coaxial with the pivot 23 having a tangent F which passes through the axis XX' of the sheath 51.

In every case, a weak return spring such as 52 shown in Fig. 8 can be used to impart to the latch 53 a rest position defined by a fixed or adjustable stop 54 of the casing when the cable 58 is no longer tensioned; a small supplementary stroke of the cable 58 in the direction of the arrow G, which may be necessary for obtaining this position of rest when the associated contactor is in its rest position, could be given at the moment of adjustment, for example with the aid of the hollow stop 55 adjustable along the axis XX· in the casing 56 to produce an appropriate displacement of the sheath 51.

When the locking operations have to be applied to more than two apparatuses, such as the contactors 57, 58, 59 seen in Fig. 9, or for example the contactor 57 should only assume its working position when the two contactors 58 and 59 are each in their respective rest position, it is possible to place in the casing 60 three latches 61, 62, 63 respectively associated with the movable elements of these contactors by flexible transmissions 64, 65, 66 analogous to those described above.

By way of non-limiting example, Fig. 10 shows a possible construction of the locking casing 60 in which each latch is associated with an individual cable 67, 68, 69 by a device comparable to that of Fig. 8, but wherein two Identical latches 62, 63 are disposed side by side and pivot on a same axis 70 in such a manner that their ends 71,72, can cooperate with an end 73 of the latch 61 which has a width A such that the tilting of one of these latches 62, 63 or of both of these two latches produces its Immobilisation. The operation of this locking device is reversible because if the latch 61 has been displaced by the apparatus 57, neither of the apparatuses 58 and 59 can assume its working state.

Zn the case where the carrying out of the function of locking of an apparatus 74 in the rest state, visible in Fig. 11 requires that two other apparatuses 75, 76 shall simultaneously be in their working state, it is possible to make use of a particular locking device 77, of which a non-limiting example ls shown. On this figure, the locking levers 78, 79, 80 are respectively associated with the said apparatuses by flexible transmissions 81, 82, 83.

A lever 79 is pivoted at 84 in the casing, and comprises a means 85 for coupling with the cable 86 analogous to that of Fig. 8; this first lever which can carry out an angular movement of amplitude oC , starting from its S1194 position of rest (shown in this figure) when the apparatus 75 ls energised in its working state, comprises at one end 87 an articulation 88 about which there oscillates a second lever 80 which can carry out an angular movement of amplitude β starting from its rest position (seen in this figure), when the apparatus 76 is energised in its working position. This amplitude β is measured here with respect to the axis YY' passing through 84 and 88.

The lever 80 which represents a first latch intended 10 to prevent the movement of a second pivoting bolt 78 comprises at its end 93 a nose 89 the active surface 90 of which is substantially perpendicular to an axis ZZ’ of the lever 80 passing through the articulation 88, and a coupling means 91 with a cable 92 of the flexible transmission 83 which is analogous to the coupling device 85.

When the apparatuses 75 and 76 are both in their working state, the movements transmitted to the lever and to the first latch by 82 and 83 add together geometrically and bring this movable arrangement into the position T^ shown in chain-dotted line, this position being obtained irrespective of the order of the movements of the elements 79 and 80.

The second latch 78, pivoted at 94 in the casing and associated with the cable 95 of the flexible transmission 81 by a device 96 analogous to those described precedingly, is formed by a lever having an end 97 which is movable from a rest position Ts illustrated In this figure; this end 97 is opposite to the surface 90 when the lever 79 and the first latch 80 are in the position T in such a manner that a rotation of amplitude of the second bolt in thedockwise direction is prevented if a traction is transmitted by the flexible transmission 81, which thus prevents the apparatus 74 from taking up its working position.

This type of locking, carrying out at the same time a logic function ANO, is not reciprocal to the extent where it permits the placing separately or simultaneously in the working state of the apparatuses 75 and 76 when the apparatus 74 is firstly placed in its working state corresponding to the position Tu of the second latch shown in chain-dotted line after carrying out the angular stroke If . Springs 98, and 100, as well as respective stops 101, 102, 103 permit the fixing of the rest positions of the corresponding elements 79, 80 and 78.

Another manner of construction of a locking casing carrying out a function identical to the preceding one is shown in Figs. 12 and 13 and makes use of the properties of addition of the movement of a differential device using for example conical pinions.

A latch 78' identical to the preceding latch 78, see Fig. 12, is here placed in a casing 77' and pivots about an axis 94' by reason of its association with the flexible transmission 81'. A second axis 104 parallel to the preceding one carries two conical pinions 105 and 106 each having a respective coupling means 107 or 108 with cables placed In respective flexible 109 and 110, these coupling means being analogous to those of Fig. 8.

Between these two pinions is disposed another latch 111 which pivots about an axis 104 and has a first end 112 placed in the vicinity of the end 37’ of the latch 78 in a manner analogous to that shown in Fig. 2, and a cylindrical extension 113 perpendicular to the axis 104 on which there is rotatably mounted a third conical pinion 114 meshing with the two pinions 106, 107.

As will be better seen in Fig. 13, the end 112 of the latch 111 is placed at a distance ”b from the end 97’ and the value of which is such that this latch will be able to describe an angular stroke ζ in the clockwise direction in order that the said end comes into a position preventing the latch 78’ from pivoting in reverse direction. This stroke S will be obtained if the movements of the movable elements associated with the pinions 106, 107 by the flexible transmissions have imparted simultaneously or separately to these pinions their respective rotations in the same direction. Here again the displacement of the latch 111, and thus the placing in the working state of the external apparatuses, (not shown) which causes it, must precede an eventual movement of the latch 78’ (which will be caused by the flexible transmission 81’) in order that the locking device functions. Furthermore, the arrangement is not reversible because an initial movement of the latch 78’ in anti-clockwise direction does not prevent the latch 111 from carrying out a fraction of its stroke.

Properties of reversibility can nevertheless be Imparted to the devices described ln relation to Figs. 11, and 13 by attached dements carried, or not, by a latch.

Thus, a lever 115 pivoting about an axis 116 of the casing 77 of Fig. 11 could place a first end 117 opposite to 89 to prevent its deplacement when a second end 118 would be lifted by the latch 78 in position Tu, see Fig. 14, this arrangement necessitating that the latch 80 shall couple unidirectionally with the lever 79 which carries it, by a stop 119 and 80 cooperating with a bearing surface 120 of 79. It will be noted again that the independence of the movements communicated to the latch 80 with respect to the movements communicated to the lever 79 result from the fact that the articulation 88 only moves slightly to one side and the other of a line XX* which constitutes the axis of the end of the flexible transmission 83 ln the casing, and that the pivot 84 is itself placed in the vicinity of XX'.

If an extension 121 situated at the end 97 of the latch 78' of Fig. 13 and having a length substantially equal to the distance b becomes placed opposite to the extremity 112 of the latch 111 solely when the latter Is in the rest position Rz and the said latch 78' is in a position Tv corresponding to the working state of the apparatus which is associated therewith, a movement of the latch 111 towards its position Tw will be prevented and the flexible 5119 4 transmissions 109, 110, will cause a locking of the two other apparatuses.

Thus, if the various casings such as 12, 60 etc. and the engagement means such as 32 have been shown as directly adhered or fixed on an electrical apparatus, in particular on contactors, these casings and engaging means could likewise be placed in the immediate proximity of these contactors or electrical apparatuses having analogous functions, that is to say apparatuses carrying out the breaking and closure of circuits either manually, such as switches, or following the occurrence of an overload, such as circuit breakers; the casing of the locking means can itself comprise two movable elements which can move for example parallely and cooperate with a third intermediate oscillating or sliding element to establish a locking of one of the two movable elements.

In every case the locking device will be removable and will comprise at least one flexible transmission for the control of the movements of at least one latch by a movable element of a movable breaker apparatus. Furthermore, it is likewise possible to control one of the two latches by a relay electromagnet the armature of which would be used solely for this purpose; this electromagnet could in its turn be placed on the casing or even therein.

Finally, the functions of locking could also make use of timing means so that the lockings take place in the course of chronological occurrences or according to predetermined sequences.

These timing means could ln their turn be placed either at a distance from a locking casing, or against it, or at the interior to control or actuate the movements of a latch.

Claims (9)

1. An interlocking equipment for effecting mutual interlockings in groups of electrical switches which are removably mounted on a chassis and each have movable 5 contacts and a movable member which is displaceable simultaneously with the contacts from a work position to a rest position, said interlocking equipment comprising: a casing for removably mounting in proximity to a first electrical switch in a group and at a distance from a second elecΙθ trical switch; first and second movable latches mounted in said casing for displacement from a rest to a working position, the said latches each having a coupling region and a latching region and being disposed one with respect to the other in such a manner that, when either one of the 15 latches is in its working position, the latching region thereof prevents displacement of the latching region of the other latch to the working position thereof; first and second openings in the said casing, the first opening serving when in use for passage therethrough of the 20 movable member of the first switch for direct engagement of the first switch with the coupling region of the first latch; a flexible transmission means having a sheath and a cable movably mounted in said sheath, the sheath having a first end mounted on the casing with the cable passing 25 through the second opening and being attached to the coupling region of the second latch, the sheath further having a second end; a catching member, having a channel opening into a recess, for removably mounting on the second switch; and a locking member displaceable within said recess and removable from said recess, said locking member being positioned when in use for direct engagement 5 with the movable member of the second switch, the second end of the sheath being mounted on said catching member with the cable passing through the channel and being removably attached to the said locking member.

2. An interlocking equipment for effecting mutual interim lockings in a group of electrical switches which are movably mounted on a chassis and each have movable contacts and a movable member which is displaceable simultaneously with the contacts from a work position to a rest position, said interlocking equipment comprising: a casing for 15 removably mounting at a distance from first and second electrical switches in a group; first and second movable latches mounted in said casing for displacement from a rest to a working position, the said latches each having a coupling region and a latching region, and being disposed 2o one with respect to the other in such a manner that, when either of the latches is in its working position, the latching region thereof prevents displacement of the latching region of the other latch to the working position thereof; first and second openings in the said casing; first 25 and second transmission means each having a sheath and a cable movable mounted in said sheath, the first and second sheaths having respective first ends mounted on the casing with the first and second cables respectively passing through the first and second opening and being attached to the respective coupling regions of the first and second latches, the sheaths further having a second end; first and second catching members, each having a channel 5 opening into a recess, for removably mounting on the first and second switches respectively; and first and second locking members displaceable within said recess of the first and second catching members respectively and removable from said catching members, said locking 1° members being positioned when in use for direct engagement with the movable members of the first and second switches respectively, the second ends of the first and second sheaths being mounted on the respective first and second catching members with the respective cable passing 15 through the respective channel and being removably attached to the respective locking member.

3. An interlocking equipment, as claimed in either of claims 1 and 2, further comprising a third movable latch mounted in said casing for displacement from a rest to a 20 working position and vice-versa and having a coupling region and a latching region, the first and third latches being disposed, with respect to the second latch, in such a manner that, when either one of the first and third latches is in its working position, the latching region 25 thereof prevents displacement of the latching region of the second latch to the working position thereof and that, when the second latch is in its working position, the latching region thereof prevents displacement of the latching regions of the first and third latches to their working positions, a third opening in the said casing, and locking means connected to the coupling region of the third latch and cooperating with the movable member of a third 5 electrical switch in a group.

4. An interlocking equipment, as claimed in either of claims 1 and 2, wherein each of the said latches consists of pivoting levers the latching regions of which are mutually abutting against each other when one of the said Ιθ levers is in its working position.

5. An interlocking equipment, as claimed in either of claims 1 and 2, wherein the said cable is adapted to transmit a rotary couple along the flexible transmission means. 15

6. An interlocking equipment, as claimed in either of claims 1 and 2, wherein each of said latches consists of a pivoting lever the coupling region of which comprises a cylindrical surface portion on which the first end of the cable is attached, the first end of the sheath being 20 located along a line tangent to the said cylindrical surface portion.

7. An interlocking equipment, as claimed in either of claims 1 and 2, wherein the said first and second latches consist of respective pivoting levers, said interlocking 25 equipment further comprising a third pivoting lever mounted in said casing for displacement from a rest to a working position and vice-versa and having a coupling end and an opposite end, the coupling end of the second lever being hinged about the said opposite end of the third lever, and locking means connected to the coupling end of the 5 third lever and cooperating with the movable member of a third electrical switch in a group, whereby the respective angular displacements of the third and second levers are added for placing the latching end of the second lever across the path of motion of the latching end of the 10 first lever.

8. An interlocking equipment, as claimed in either of claims 1 or 2, wherein the said second latch comprises a pivoting lever rotatably mounted about an axis which is fixedly mounted in the casing, first and second conical 15 pinions being rotatably mounted about the said axis and having a cylindrical coupling surface, and a third conical pinion being attached to the said second latch at right angles to the plane thereof, said third conical pinion working with the first and second conical pinions, and 20 first and second transmission means, each having a sheath, the said sheaths each having a first end removably mounted in the casing, with the first and second cables passing through second and third openings and being respectively tangentially attached to the cylindrical coupling surface 25 portions of the first and second conical pinions respectively, the said sheaths further having a second end, the second ends of the sheaths of the first and second transmission means being positioned when in use to cooperate with the respective movable members of second and third switches in a group.

9. An interlocking equipment substantially as 5 described herein with reference to the accompanying drawings.