Device for rendering contactors electrically and mechanically inoperative

BACKGROUND OF THE INVENTION

The present invention relates to a device for rendering contactors mechanically and electrically inoperative, in which the original design of the mobile elements makes it possible to obtain an arrangement of the output terminals which facilitates wiring and interchangeability with existing systems providing mechanical inoperativeness.

1. Field of the Invention

It is generally known that devices of this kind providing such inoperativeness are usually associated with contactors for controlling electric motors so as to prevent simultaneous switching on and so short-circuiting particularly when these contactors provide reversal of operation and star-triangle starting.

Such inoperativeness may be electric alone, however, in order to prevent operating errors, it is preferable for it to be both electric and mechanical.

The provision of electric inoperativeness between two contactors consists in actuating, in the first third of the travel of the closing contactor, but preferably as early as possible, a contact which opens the circuit of the coil of the other contactor and vice-versa.

Mechanical inoperativeness uses a system of levers which are interlocked so that when one contactor has begun to close, it is impossible to close the other.

In automatic operation, electric inoperativeness alone would be sufficient. However, in the case of the simultaneous energization of two contactor coils, or in the case of a shock causing the movement of their mobile assemblies, or else in the case of wrong actuation of these contactors, there is a risk of short-circuiting by the simultaneous closure of the power poles of both contactors. This is why mechanical inoperativeness is generally associated with electric inoperativeness.

2. Description of the Prior Art

To provide such mechanical inoperativeness, even in the case of contactors mounted side by side, a locking mechanism is generally used incorporated in a case from which project movement take-off fingers. This case is then placed between two contactors so that the movement takeoff fingers are coupled respectively with actuation members provided in said contactors.

The electric inoperativeness is generally provided by using one of the break contacts (or NC as they are generally called) usually provided on each of the contactors, it being understood that this solution has the drawback of reducing the number of contacts available on each contactor.

To overcome this drawback, a device has been proposed in the form of a module adapted for fitting between the two contactors to be locked and comprising both levers providing mechanical inoperativeness and contacts providing electric inoperativeness. A device of this kind which provides simultaneously mechanical and electric inoperativeness is described in the French patent issued to the firm UNELEC, No. 2 045 090 on May, 30, 1969.

Another more recent and more compact device which can be used between two contactors is described in the PCT patent to ALLEN BRADLEY COMPANY (USA) No. 85 03382 dated Jan. 23, 1984.

It can however be observed that the embodiments proposed in this patent have the drawback that the input and output terminals assigned to one of the contacts are placed on the same side of the case of the device whereas the input and output terminals of the other contact are placed on the other side of this case. This feature, which results from the general design of the device, is particularly troublesome, not only in so far as safety and the simplicity of providing interconnecting wiring are concerned, but also the risks of error which this arrangement may give rise to.

The purpose of the invention is particularly to overcome these drawbacks.

SUMMARY OF THE INVENTION

For this it provides a device rendering contactors electrically and mechanically inoperative of the type comprising:

a flat case with two opposite parallel front walls, spaced a small distance apart and, at least two opposite sidewalls which extend in planes substantially perpendicular to said front walls, this case being formed so as to be able to be mounted between two contactors disposed side by side ;

first and second movement take-offs adapted for respectively coupling with the mobile assembly of the two contactors through substantially coaxial apertures provided in the central regions of the two front walls, each of these two movement take-offs being movable between two positions corresponding respectively to the work position and the rest position of the contactor with which it is associated ;

mobile elements providing reciprocal inoperativeness, driven respectively by said movement take-offs, these mobile elements having a travel distance such that the passage of one of the movement take-offs to the work position brings the element which corresponds with it to a position preventing the passage of the other movement take-off to the work position; and

two switch devices each comprising at least one pair of fixed contacts connected respectively by connecting conductors to an input connection element and to an output connection element, and a mobile contact element actuated by a corresponding mobile element providing inoperativeness.

According to the invention, in this device providing inoperativeness said input connection elements are mounted on one of said sidewalls of the case whereas said output connection elements are mounted on the other sidewall, and said switch devices form with the input and output devices which are associated therewith as well as with the corresponding connection conductors, two through current lines, without crossing inside the case and directed transversely with respect to said sidewalls of the case.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the invention will be described hereafter, by way of non limitative examples, with reference to the accompanying drawings in which :

FIG. 1 shows in a front view one embodiment of a device of the invention associated with two contactors in the rest position;

FIG. 2 is a view similar to that of FIG. 1 but in which the first contactor is in the work position and the other is in the rest position;

FIG. 3 shows the same device with the first contactor in the rest position and the other in the work position;

FIG. 4 shows in a front view another embodiment of the device of the invention; and

FIG. 5 is a diagrammatical representation of another variant of the device of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Such as shown in FIGS. 1 to 4, the device providing mechanical and electric inoperativeness comprises :

a support case 1,

a lever 2 mounted for rotation about a fixed pin 4 fixed to case 1, this lever 2 being rotated by a first pin 6 adapted for coupling with the mobile assembly of a first contactor,

a pusher 3 mounted for sliding inside case 1 along a linear path, by means of slides 5, 5', this pusher 3 being driven by a second pin 7 adapted for coupling to the mobile assembly of a second contactor,

two switch devices I₁, I₂ of the double break contact type whose mobile parts 12, 13 are respectively carried by the pusher 3 and lever 2, preferably via a resilient crushing system, and whose fixed parts each comprise a pair of fixed contact elements 15, 16, 17, and 18 respectively connected to the input and output terminals 19, 21, 20, and 22.

The input terminals 19, 21 are situated on one side 40 of the case (preferably at the level of one of its lateral edges) whereas the output terminals 20, 22 are situated on the other side 39 of the case (preferably at the level of the lateral edge of the case opposite the preceding one), so that when the switch devices I₁, I₂ are closed, the current lines pass through the case lin a direction substantially perpendicular to that of sides 39, 40.

As mentioned above, lever 2 and pusher 3 are interlocked respectively with the movements of the mobile assemblies of the contactors by means of pins 6 and 7; for this, these pins project on each side of case 1 through openings 14, 14a formed in its two opposite front walls, so as to be able to engage in housings provided in the mobile assemblies of the contactors. The edges of the openings 14, 14a are oriented in a direction which corresponds to the direction of movement of the mobile assembly of the contactors.

More precisely, lever 2 comprises three arms B₁ to B₃ joined together by two portions bent substantially at right angles C₁, C₂ in the following arrangements :

the first arm B₁ is adapted so as to occupy a position such as that shown in FIG. 1 in which it extends substantially parallel to the axis of movement of pusher 3 at a given distance therefrom,

the second arm B₂ is connected to the first arm B₁ by the bent portion C₁ through which pin 4 passes, and extends in the direction of the axis of movement of pusher 3, the end of this arm situated opposite the bent portion C₁ carrying pin 6,

the third arm B₃ is connected to said end of arm B₂ by the bent portion C₂ so as to extend, in the position shown in FIG. 1, parallel to and in line with pusher 3, this third arm B₃ having at its end the mobile part 13 of the switch device 1₁.

Pusher 3 comprises a lateral protuberance P oriented towards arm B₁ of lever 2 and has at its end opposite the end of arm B₃ the mobile part 12 of a switch device I₂.

This protuberance P is more particularly adapted so that its area of movement overlaps that of lever 2 and so that conversely, the area of movement of the lever overlaps that of said protuberance P, so as to be able to obtain the following operation.

When the contactor which drives pusher 3 is closed, as shown in FIG. 2, the switch device I₂ which is generally placed in series with the coil of the other contactor is open.

If, however, in this position an attempt to close the other contactor is made, tending to move lever 2, the surface 10 of said lever 2 will abut against the surface 11 of protuberance P of said pusher, thus preventing said closure.

Similarly and, in accordance with FIG. 3, when the contactor secured to lever 2 is closed, the switch device I₁ generally placed in series with the coil of the first contactor is open. If, in this position, an attempt to close said first contactor is made, the surface 8 of protuberance P of pusher 3 will abut against surface 9 of lever 2 and will prevent said closure.

The mechanical inoperativeness thus achieved, through the combination of the translational/rotational movements of pusher 3 and lever 2, proves very efficient for the movements of surfaces 8 to 11 which block each other are practically perpendicular.

With the above described arrangement and because there is no crossing of electric connections inside case 1, it becomes possible to use a case of small thickness which may readily replace existing cases providing mechanical ioperativeness. Furthermore, the rectilinear or substantially rectilinear movement of the movement take-off parts simplifies adaptation to the mobile assemblies of the contactors.

FIG. 4 shows another embodiment of the invention which uses more conventional interlocking levers 23 and 24.

One of levers 23 is modified and comprises an additional arm 38 on which at least one mobile contact 25 is placed which closes the fixed contacts 26 and 27 connected to terminals 28 and 29.

The other lever 24 also has, on a portion close to its locking surfaces, at least one mobile contact 30 which closes the fixed contacts 31 and 32 connected to terminals 33 and 34.

The movement take-offs are conventionally formed by pins 35 and 35a passing through the openings 36 and 36a in case 37.

The arrangement of the contacts, such as described, also makes it possible to have current paths, passing through the case, substantially perpendicular to the direction of movement of the mobile assemblies of the contactors to be made inoperative, which is materialized by the direction of the openings 36 and 36a.

This arrangement and the absence of connection crossings inside the case makes possible as reduced a thickness as possible.

It should be noted that, in this solution, levers 23 and 24 may be made in the same mold, the additional arm 38, required on lever 23, being removed from lever 24 after molding thereof.

It should also be noted that, in the two embodiments, the term input or output for the connection terminals is only given for the sake of clarity of the explanation and in no wise prejudges the actual subsequent assignment of said terminals.

The device shown in FIG. 5 is based on a principle similar to that of the above described example.

However, in this case, the two levers 50, 51 are formed of molded parts of identical shape each having two impressions 52, 53-54, 55 each adapted to receive a mobile contact bridge. These two levers 50, 51 are mounted for rotation about two respective pins 56, 57 disposed symmetrically with respect to the median plane of symmetry P, P' of case 58.

Each of these levers 50, 51 has three arms 60, 61, 62-63, 64,65 disposed in the form of a fork which are connected, by one of their ends to a common region 66, 67 through which one of said pins 56, 57 passes.

Actuation of one of the two levers 50, 51, from a corresponding contactor, is provided by means of a pin 68, 69 mounted on the free end of its central arm 61, 64 and which passes through an oblong aperture 70 centered on the plane of symmetry P, P'.

The other two arms 60, 62-63, 65 of this lever 50, 51 are equipped with reception means (impressions 52 to 55) adapted each for receiving a mobile contact bridge.

As in the above described example, this device comprises two through current lines, namely an upper line 71 and a lower line 72, each of these lines comprising a switch device including two fixed contact elements and a mobile contact bridge carried by a corresponding lever.

The upper through line 71 is formed so as to define in case 58 a free space of substantially trapezoidal shape inside which arms 60, 63 of levers 50, 51, which provide the locking function, may move.

The fixed contact elements 73, 74 of the upper current line 71 are then disposed at the level of one of the oblique sides of said free space and cooperate with a mobile contact bridge 75 carried by the arm of the lever 63.

The lower through line 72 extends in a plane offset with respect to the mean plane in which levers 50, 51 move, so as to facilitate the passage of one 76 of the two conductors 76, 77 of this line.

This through line 72 comprises, opposite the oblique side of the upper line including the fixed contact elements 73, 74 an oblique part 78 including two fixed contact elements 79, 80 which cooperate with a mobile contact bridge 81 carried by the arm of lever 62.

It should be noted that in this case the reception means 52, 54 provided on arms 60, 65 are not used.

The advantages of the above described solution are its simplicity and the fact that, since it only uses a single type of lever, it lends itself better to mass production and is of a lower cost price.