EP0717426A1

EP0717426A1 - An auxiliary modular device for modular circuit-breakers

Info

Publication number: EP0717426A1
Application number: EP95203387A
Authority: EP
Inventors: Sergio Pianezzola; Sergio Peroni
Original assignee: BTicino SpA
Current assignee: BTicino SpA
Priority date: 1994-12-16
Filing date: 1995-12-07
Publication date: 1996-06-19
Anticipated expiration: 2015-12-07
Also published as: ATE177874T1; SI0717426T1; IT1271772B; ITMI942550A0; GR3030523T3; EP0717426B1; DE69508364T2; ES2131761T3; ITMI942550A1; DE69508364D1

Abstract

In an auxiliary modular device for modular circuit-breakers, the mode of operation of a switching contact of the auxiliary device can be preset from two modes of operation by means of a cam selection device operable from the front of the auxiliary device, and an indicator flag facing the front and a test button operated from the front enable the functionality of the equipment and the preset mode of operation to be checked.

Description

The present invention relates to an auxiliary modular device for modular circuit-breakers and, in particular, to a device for operating auxiliary indicator contacts.
It is known that there are modular electrical devices, also called DIN modules, on the market for installation beside one another on a rail conforming to that standard.
Essentially, these electrical devices consist of modular circuit breakers with thermomagnetic protection and of differential protection modules.
There is, however, a wide range of auxiliary equipment, particularly modules for operating auxiliary indicator contacts or simply auxiliary contact modules.
The modules are constituted by housings each formed by two coupled half-shells which house one or more auxiliary switching contacts, terminals for connecting the contacts to external cable ends and kinematic mechanisms which cause the contacts to switch.
These kinematic mechanisms are mechanically interlocked with at least one power switch module on account of the positioning of the auxiliary module beside it and consequent coupling to the kinematic mechanisms of the power module.
In particular, a first interlocking link consists of the mechanical coupling of a manual (or motorized) setting and release lever of the contact-breaker with a similar manual lever for switching the auxiliary contacts, and a second interlocking link consists of the coupling of an automatic release and opening device of the circuit-breaker with a similar device for tripping the auxiliary contacts.
It should also be noted that, in automatic circuit-breaker modules, the internal kinematic mechanisms are such that the action of the thermomagnetic and differential protection devices on the device for the release and opening of the contact-breaker brings about the return of the setting lever to the release position.
This occurs with a certain delay due to the structure of the kinematic mechanisms and to the greater inertia of the setting lever compared with that of the devices supporting the movable contact which opens much more quickly.
To satisfy various installation requirements, modules with auxiliary indicating contacts are on the market in which an auxiliary contact can operate in two ways:

A) (switching mode): the auxiliary contact switches its own position (closing onto one or other of two fixed contacts) for each opening or closure of the circuit-breaker contacts, regardless of whether the opening of the circuit-breaker contacts is due to manual release or the operation of the protection device (tripping of the relay),
B) (relay tripping mode): the auxiliary contact switches only when the protection device is operated automatically (tripping of the relay).

The required mode of operation can be selected and set by means of a pawl operable by a screw on one side of the auxiliary contact module with its axis of rotation perpendicular to the plane in which the modules are juxtaposed.
This arrangement, which is dictated by structural requirements, has the serious disadvantage that, when the modules are installed side by side on a rail it is no longer possible to modify the mode of operation of the auxiliary contact.
Moreover, even if there is a window opening at the front which enables the position of the pawl, and hence the operative mode selected to be identified, there is no visual indication of the actual position of the auxiliary contact nor, what is more, is there any way of checking that the auxiliary contact has switched on account of the relay having tripped or that the auxiliary module is behaving according to the desired mode of operation.
A further disadvantage of the known auxiliary modules, when they have two switching contacts, is that the order in which one contact switches relative to the other is not always the same but changes according to the direction of switching.
In many applications, however, it is convenient or necessary for the two contacts always to switch in the same order, regardless of the direction of switching, at least when the relay trips.
The auxiliary modular equipment of the present invention, which has a device for selecting the mode of operation of the contact which can be operated from the front of the module even when the module is installed beside other modules, avoids these disadvantages and these limitations.
The device comprises a screw cam which can rotate through a predetermined arc limited to 90° and can adopt two stable operative positions, and a keeper for locking the kinematic mechanism. The locking is prevented selectively by the interference of the keeper with the cam.
The cam is housed rotatably with its axis parallel to the plane of juxtaposition of the module and with an operating head facing the front of the auxiliary module, in a socket formed without any undercut by two juxtaposed housing half-shells.
The socket also provides for the axial positioning of the cam ensuring that it cannot be lost, for the limitation of the angle of rotation, and for the biasing of the cam to one of two predetermined operative positions.
The kinematic mechanism for switching the contact has a flag-like arm which enables the position of the contact to be seen.
There is also a test button which, by acting on the tripping device of the auxiliary device, enables the tripping of the relays of the contact breakers to be imitated and the switching of the contact, and hence the pivoting of the flag, to be checked visually without the need to use electrical instruments or to subject the system to overload and/or short-circuit conditions.
According to a further aspect of the present invention, an auxiliary kinematic delay mechanism is also advantageously provided for ensuring, in a device with two auxiliary contacts, that the switching of one contact is delayed relative to the switching of the other for both directions of switching, in the event of tripping of the relay.
The characteristics and advantages of the invention will become clearer from the following description of a preferred embodiment and from the appended drawings, in which:

Figure 1 is a perspective view showing a preferred embodiment of an auxiliary modular contact device,
Figure 2 shows schematically the electrical and kinematic structure of the device of Figure 1,
Figure 3 is a graph showing the relationship defined by the kinematic mechanism of Figure 1 between the rotation and the travel of two elements of the kinematic mechanism,
Figure 4 is an exploded, perspective view of a preferred embodiment of the kinematic mechanism of Figure 2,
Figure 5 is an exploded, perspective view of a preferred embodiment of a cam for selecting the mode of operation for the kinematic mechanism of Figure 2.

For a better understanding of the problem solved by the invention, Figure 1 is a perspective view showing an auxiliary modular contact device according to the present invention.
The device is constituted by a housing of generally flat, rectangular, parallelepipedal shape with a front face 1, an opposite rear face, two parallel side faces, one of which, indicated 2, is visible, and a further two faces, an upper face and a lower face, respectively, one of which is visible, indicated 3.
The faces of the housing are defined in this manner with reference to the conditions of installation which provide for the module to be fixed with its rear face in contact with a rail supported by a vertical wall and with its side faces vertically in contact with the side faces of other modules.
The auxiliary module is positioned and anchored to the adjacent modules by means of alignment pins 4, 5 and coupling devices 6, 7, preferably, but not necessarily, of the type described in European patent application No. 94201433.3, formed on the side face 2.
A slot 8 also opens in the side face 2, and a pin 9 projects therefrom for coupling between an internal release kinematic mechanism and a corresponding release kinematic mechanism of a circuit-breaker module, in known manner.
The housing houses at least one switch contact, preferably two switch contacts, kinematic mechanisms for connecting the contacts, and terminals for connection to contacts of external cable ends.
The terminals are accessible by means of holes in the housing formed in the lower or upper wall, or in both, and in a portion of the front wall.
In Figure 1, holes 10, 11, 12, 13 for the insertion of external cable ends into the terminals and holes 14, 15, 16, 17, 18, 19 for access to the screws for clamping the terminals can be seen.
A lever 20, exposed on the front face 1, for the manual setting of the contacts is articulated in the housing and is coupled mechanically, in known manner, to a corresponding manual setting and release lever of a circuit-breaker module disposed beside the auxiliary module.
According to the present invention, a screw head 21 for operating a cam device for selecting the mode of operation of the contact is exposed on the front face 1.
The front face 1 also has a window 22 facing an indicator flag which is operated by the internal kinematic mechanisms and displays the switched or unswitched state of the internal contact the mode of operation of which can be selected.
The indicator flag provides a positive or direct indication of the state of the contact and of the mode of operation selected; if the mode of operation is for indicating switching of the auxiliary contact, the indicator flag changes its indication for each manual setting and release operation carried out on the setting lever.
However, after a first manual setting operation, the indication does not change for each successive setting and release operation if the mode of operation set is that of switching of the auxiliary contact on account of tripping of the relay.
The manual setting and release of the auxiliary module do not allow the switching of the auxiliary contact owing to tripping of the relay to be checked positively by means of the flag.
To permit this check, according to the invention, the auxiliary module has a test button 23 facing the front of the device.
The test button acts on the internal kinematic mechanism in the same way in which the protection operation of an associated contact-breaker module would act on account of the tripping of the relay and brings about switching of the auxiliary contact which can be checked visually by the change in the indication of the flag.
Figure 2 shows schematically the kinematic mechanism of the auxiliary module formed according to the present invention.
The module comprises a first movable contact 24 which is electrically connected to a connection terminal A and can be switched so as to close and open, respectively, relative to one of two fixed contacts 25, 26 electrically connected to the connection terminals B and C, respectively, as well as a second movable contact 27 which is electrically connected to a connection terminal D and can be switched so as to close and open, respectively relative to one of two fixed contacts 28, 29 electrically connected to connection terminals E, F, respectively.
The contacts 24, 27 are biased to the rest positions in which they are closed, respectively, onto the fixed contacts 25, 28 by respective resilient support arms (or contact arms ) 30, 31, as shown, or by resilient biasing means such as springs.
The kinematic mechanism for operating the contacts comprises a bistable manual setting and release lever 32 to which there is articulated a setting rod 34, the free end of which pushes against the end of a first class lever 33 the other free end of which pushes against an axially slidable rod 35.
The rod 35 exerts a pull on the contact support 30 to switch the movable contact 24 so that it closes onto the contact 26.
The kinematic mechanism is set by the pivoting of the lever 32 in the sense indicated by the arrow M as far as a bearing abutment 37.
When the mechanism is set, the rod 34 and the lever 33 adopt the stable positions indicated by broken lines and identified by the reference numerals 34A and 33A.
In this condition, a release device shown schematically in Figure 2, such as a lever 36 with three arms which is pivoted anticlockwise by a tripping control CS (applied by means of the pin 9 of Figure 1) moves the end of the rod 34 away from the position in which it bears on the end of the lever 33 and enables the latter to pivot clockwise, consequently allowing the rod 35 to be returned to the rest position by the action exerted by the resilient support arm 30 of the contact 24 which switches to the rest position.
The lever 36 is biased to the rest position by a spring, not shown.
The kinematic mechanism is released manually by returning the lever 32 to the rest position.
Clearly, the state of the movable contact 24 "copies" the state of the contact-breaker devices associated with the auxiliary module, regardless of whether they are operated manually or operate automatically.
The operating rod 35 is coupled by push-fitting onto a rod 38 which in turn pushes the movable contact 27, switching it so that it closes onto the contact 29.
In the absence of other constraints, the contact 27 "copies" the state of the contact 24.
A second kinematic mechanism which can be made inoperative selectively, enables the contact 27 to operate in a different manner, that is, to switch only on account of tripping of the relay.
The second kinematic mechanism comprises a lever 39 pivoted at a fulcrum 40 and coupled by a slot 41 to a peg on the rod 38.
It also comprises an engagement keeper 42 shown schematically as a lever with three arms pivoted at 43 and biased to an engagement position by a spring 44.
When the rod 38, pushed by the rod 35, switches the contact 27 so that it closes onto the fixed contact 29, it pivots the lever 39, moving it to the position shown by a broken line and indicated 39a.
In this position, the opposite end of the lever 39 to the slot 41 is engaged by the keeper 42.
A cam 45 fixed to the manual setting lever interferes with one of the arms of the keeper 42, moving it to an inoperative position for positions of the lever 32 near to the setting position.
This will be explained in greater detail below; in the event of manual release, the keeper 42 returns to the engagement position before the lever 39 pivots far enough to prevent engagement.
The lever 39 is then locked in the position 39A and in turn locks the operating rod 38 in a position which prevents the contact from switching.
In the event of the relay tripping, on the other hand, the release device 36 releases the lever 33, allowing the rod 35, the rod 38 and the lever 39 to return rapidly to the rest position as a result of the resilient biasing of the contact supports 30 and 31, before the pivoting of the lever 32, and hence of the cam 45, allowing the keeper 42 to return to the engagement position.
Both the contact 24 and the contact 27 are thus switched.
The contact 27 thus operates as a contact which switches solely on account of tripping of the relay.
To allow the contact 27 also to switch in the event of manual release, an eccentric cam 46 can be rotated manually between a first angular position in which the cam does not interfere with the keeper 42 and a second angular position in which it interferes with one of the arms of the keeper 42, moving it to the inoperative position.
The behaviour of the auxiliary contacts and the visual control of the functionality of the module are ensured by an appendage BB fixed to the lever 39 which, as already explained with reference to Figure 1, is disposed like a flag facing a window 22 opening in the front of the housing and indicates whether the contact 27 is closed onto the contact 28 or onto the contact 29.
If the manual setting and release of the lever 32 are accompanied by a corresponding change in the indication of the flag BB they permit confirmation that the contact 27 is functional and is operating in switching mode.
It is not possible, however, to check the functionality of the module when the contact 27 is operating so as to switch solely on account of the tripping of the relay.
In order also to permit this check, the auxiliary module has a test button 47 accessible from the front of the module (Figure 1) which acts on a lever arm of the release device 36 and, once the module has been set manually, enables the setting rod 34 to be released from the lever 33 so that the two contacts 24, 27 switch and return to the rest position.
The switching is made visible by the change in the indication of the flag BB.
Advantageously, there is also a further supplementary kinematic mechanism which ensures a predetermined operating sequence in the switching of the two contacts 24 and 27.
The kinematic mechanism, which is very simple, consists of an auxiliary lever 48, pivoted at an intermediate point, with a first slotted end 49 which engages a peg on the rod 38 so that the lever 48 is forced to pivot as a result of axial movements imparted to the rod 38.
The setting lever 32 has, in addition to the cam 45, a second projecting cam (or tooth) 50 which, when the lever 32 is pivoted to the setting position, interferes with a second end 51 of the auxiliary lever 48 and forces it to keep the rod 38 in the position in which the contact 27 is closed onto the contact 29.
In the event of the relay tripping, the interference between the cam 50 and the end 51 of the auxiliary lever ensures that the movable contact 27 switches onto the fixed contact 28 after the movable contact 24 has already switched onto the fixed contact 25.
This ensures that the order of switching of the two movable contacts is the same for switching both in one direction and in the other since, in general, to prevent uncertainty in the switching order, the dimensions of the kinematic mechanism formed by the rods 35, 38 which couple the two movable contacts mechanically are such as to ensure that, for setting, the contact 24 switches onto the contact 26 before the contact 27 switches onto the contact 29.
The locking function of the lever 42 and the delaying function of the auxiliary lever 48 can be understood more easily by a consideration of the graph of Figure 3 which shows qualitatively the relationship which the kinematic mechanisms establish between the rotation φ of the setting lever 32 and the travel S of the rods 35, 38 in the various cases of manual setting and release (graph I) with switching of the contact 27, of switching on account of the tripping of the relay (graph II), and of switching on account of tripping of the relay with delayed switching of the contact (graph III).
The field φ0-φM defines the various angular positions which the lever 32 adopts as it moves from the release position to the set position.
The field φ8-φM defines the angular positions of the lever 32 for which the cam 45 prevents the keeper 42 from acting on the lever 39.
The field φ9-φM defines the angular positions of the lever 32 for which the cam 50 interferes with the auxiliary lever 48.
The distances travelled S1, S2, S3, S4, S5 define the positions of the rod 35 and of the rod 38 for which, respectively:

S1:-: the contact 24 is opened/closed relative to the contact 25,
S2:-: the contact 27 is opened/closed relative to the contact 28,
S3:-: the contact 24 is opened/closed relative to the contact 26,
S4:-: the contact 27 is opened/closed relative to the contact 29,
S5:-: the travel limit below which the lever 39 cannot be engaged by the keeper 42.

In the case of manual setting (graph I) the closure and opening of the contacts take place in the order S1, S2, S3, S4.
In the case of manual release, if the cam 46 prevents the operation of the keeper 42, the closure and opening of the contacts take place in the reverse order S4, S3, S2, S1.
The auxiliary lever 48, if there is one, has no effect.
If, on the other hand, the cam 46 is arranged for the mode of operation for switching only on account of the tripping of the relay, the angular position φ8 of the lever 32 corresponds to a travel of the rod 38 greater than the engagement travel limit S5.
The contact 27 therefore remains in the switched position and only the contact 24 switches, in the order S3, S1.
In the event of tripping of the relay and in the absence of the auxiliary lever 48, the breaking of the articulation between the rod 34 and the lever 33 allows the rods 35, 38 to return quickly to the rest position, regardless of the rotation of the lever 32.
The inertia of the kinematic mechanisms and the magnitudes of the biasing forces acting in any case define a relationship between the travel S and the rotation φ shown qualitatively by the graph II.
In this case, the lever 32 reaches the angular position φ8 at a point when the travel S of the rod 38 is far below the engagement limit S5.
The order of switching of the contacts is thus given by the sequence S4, S3, S2, S1.
If the auxiliary lever 48 is present, the graph II still represents the relationship between the travel of the rod 35 and the rotation of the lever 32, but the relationship between the travel of the rod 38 and the rotation of the lever 32 is represented by the graph III.
In fact, it is clear that the rod 38 can start to move only if the lever 32 has reached the position φ9.
Clearly, therefore, the order of switching of the contacts is given by S3, S4, S1, S2.
It should be noted that the auxiliary lever 48 may advantageously be used even in auxiliary modules in which the manual setting lever 32 does not return to the release position on account of the operation of the tripping device, that is, on account of the tripping of the relay, but requires manual resetting.
In this case, with reference again to Figure 2, it can be seen that the toothed cam 50 interferes with the end 51 of the auxiliary lever 48, preventing it from pivoting.
The auxiliary lever 48 in turn prevents the rod 38 from moving.
The switching of the contact 27 is thus prevented until the setting lever is reset manually and, in short, the switching of the contact 27 is delayed relative to the switching of the contact 24 which is switched upon the tripping of the relay.
Clearly, in this case, the lever 39 and the device for selecting the mode of operation of the auxiliary contact 24 are superfluous and ineffective since the locking action of the auxiliary lever 48 prevails over the action of the lever 39 whatever mode of operation is set.
The general aspects of the invention having been described, Figures 4 5 are exploded, perspective views showing, respectively, preferred embodiments of the various kinematic mechanisms and of the cam device for selecting the mode of operation.
In the drawings, the various elements corresponding to those of Figure 2 are identified by the same reference numerals.
In Figure 4, the conventional setting lever 32 can readily be seen in the form of a drum with a setting arm.
Along a rim of the drum there is a recess 45A with a function similar to that of the cam 45 of Figure 2.
The drum is rotatable, in known manner, on a pin 52 fixed to the casing, not shown.
The setting rod 34, which is articulated on the drum, has an end 53 which engages against a tooth 54 of the lever 33.
The end 53 of the rod is kept in contact with the tooth 54 by a pawl 55 articulated on the lever 33.
The pawl 55 is kept in the engagement position by a spring 56 and is operated by the release lever 36 which is pivoted, together with the lever 33 on a pin 57 fixed to the casing.
The release lever 36 is formed by two bodies 36A, 36B which are shown as separate bodies but constitute a single unit.
The body 36A has a pin 9 for operating the release lever from outside the housing, as explained with reference to Figure 1, and acts on the pawl by means of an arm 58.
The body 36B has a second arm 59 on which the end of an arm 60 of the test button 47 acts.
The test button is conveniently of plastics material and has an integral leaf spring 61 which biases the button towards the rest position.
The button 47 is housed in a seat 62 in a half-shell 63 of the housing, in the front face thereof.
The leaf spring 61 pushes against an internal rib 64 of the housing.
The arm 60 of the test button interferes with the wall of the housing, limiting the outward travel of the button relative to the housing, preventing the button from being lost.
The lever 33 acts on the rod 35 by means of a second lever 65 pivoted on a pin 66 fixed to the housing and having a slot 67 cooperating with a peg on the rod 35.
An end of the rod 35 has a tooth which interferes with a leaf spring 30 supporting the movable contact 24 which switches closed/open relative to fixed contacts, of which only one 26 is shown.
The other end of the rod 35 pushes against the rod 38 which is of a double-L shape and has a portion disposed parallel to the rod 35.
The end of the portion of the rod 38 which is parallel to the rod 35 has a tooth which interferes with a leaf spring 31 supporting the movable contact 27 which switches closed/open relative to the fixed contacts 28, 29.
The other end of the rod 38 has a peg which is coupled with a slot 167 in the lever 39.
The lever 39, which is pivoted on a pin 68 fixed to the housing, has an arm 69 which terminates in a flag 70 facing a hole in the front of the housing, not shown.
An engagement keeper 42 articulated on a pin 71 fixed to the housing and biased towards the active position by a spring, not shown, locks the lever 39 in the set position.
The keeper 42 has a lever arm 72, the end of which is inserted in the recess 45A of the setting drum and, by interfering with the drum when it is in the set position, moves the keeper 42 to the inactive, release position.
The keeper 42 is also de-activated by the rotary cam 46 which acts on an arm 73 of the keeper 42.
Figure 5 is an enlarged, perspective view showing a preferred embodiment of the cam 46 and its support, formed by the half-shells of the housing on the front face of the auxiliary device.
The need to be able to operate the cam from the front of the housing with strict size limitations imposed by the device, together with the constraints imposed by the production technology for the moulding of the housing half-shell, involve the need to overcome considerable technical problems.
The cam 46, which is preferably of plastics material, comprises a cylindrical head 73 which has a groove 74 on an outer face for actuation by means of a screwdriver or similar tool, and which is extended axially on its opposite face by a pin 75 of smaller diameter.
A stop and rotation-limiting tooth 76 in the form of a cylindrical sector of diameter equal to that of the head and of the order of 5 mm is formed on the pin 75 adjacent the head 73.
At the opposite end of the pin 75 there is a cam profile with an actuation tooth 77 advantageously extending radially relative to the axis of the pin 75 and preferably aligned radially with the axis of the actuation groove 74.
The cam profile also has an inactive sector 78 with an outside diameter larger than that of the pin and an active sector 79 of larger diameter, which extends through an arc of the order of 120°, and in which there are two notches 80, 81 spaced apart by an angle of 90°.
A semicylindrical socket 82 for the head 73 and the tooth 76 is formed by moulding without an undercut in the front face of the housing half-shell 1 and is defined internally by a half-collar 73 which forms a semicylindrical support with a diameter equal to that of the pin 75 and an axial length equal to that of the pin 75 less the axial dimension of the tooth 76.
A stop tooth 84 like a sector of a ring is formed in the socket 82 and cooperates with the tooth 76.
A semicylindrical socket 85 for the head 73 is moulded, without an undercut, in the front face of the half-shell 2.
At a suitable axial distance from the socket 85 equal to the axial thickness of the tooth 76, is a support plate 86 which extends to form a semicylindrical end support 87 which is coupled with the half-collar 83.
The support plate 86 is fixed to the wall of the half-shell 2 by a rib 88 which extends as far as the semicylindrical support 87 to form a stop tooth 89 cooperating with the tooth 76.
The two teeth 84, 89 cooperate with the tooth 76 to limit the rotation of the head 73 and of the associated active cam tooth 77 to an angle of 90° so that the tooth can adopt two end positions, an active position in which the tooth 77 acts on the keeper 42 (Figure 4), and an inactive position in which the tooth 77 does not interfere with the keeper 77 and the keeper is free to engage and lock the lever 39.
When the head 73 is operated from outside it is subjected to a moment which can generate quite large torsional stresses in the body of the device, particularly when the tooth 76 interferes with the teeth 84 and 89.
This moment is discharged, through the tooth 76 fixed to the head 73, to the teeth 84 and 89 without affecting the pin 75 which is of smaller diameter and limited torsional strength.
The stability of the end positions adopted by the cam is ensured by a resilient arm 90 formed in the half-shell 2 of the housing and terminating in a tooth 91 which is housed in the notches 80 and 81 for the two end positions of the cam, respectively.
The foregoing description relates solely to a preferred embodiment and clearly many variations may be applied thereto.
For example, the auxiliary device may also comprise a single switch contact corresponding to the contact 27 of Figure 2, the mode of operation of which can be selected from the two indicated.
In this case, all of the elements enclosed by the broken line 93 in Figure 2 are superfluous, as is the kinematic delay mechanism 48, 49, 50, 51.
The arrangements of the terminals and of the contacts in the housing shown in Figure 4 and in Figure 1 may also be different and may correspond to the diagram of Figure 2 in which the terminals open in two opposite faces of the housing.
Finally, the cam for selecting the mode of operation may be biased by a pin 75 with a partially circular and partially polygonal cross-section, the polygonal section of the pin cooperating with half-supports which are also partially polygonal and partially semicylindrical, rather than by a resilient arm such as the arm 90 of Figure 5, cooperating with cam recesses or teeth.
In this case, the relative resilience of the coupling between the two half-supports is used to ensure the two stable active and inactive positions of the cam.

Claims

An auxiliary modular device for a circuit-breaker, for installation on a rail beside the circuit-breaker, having at least one first auxiliary switching contact and one device for selecting the mode of operation of the auxiliary contact from switching which mirrors the switching of the contact of the circuit breaker and switching solely on account of the tripping of the relay of the contact-breaker,
the auxiliary device comprising a housing of plastics material constituted by two coupled half-shells and having a front face which is accessible to the user even when the device is installed, a manual setting and release device which can be coupled to the contact-breaker and a setting release device which can be coupled to the contact-breaker,
characterized in that
the housing half-shells form a rotation support and an axial restraint with an axis perpendicular to the front face of the device for a cam for selecting the mode of operation, and in that the device comprises the cam, the cam having a shaft mounted rotatably in the support and having an actuation head accessible from the front face.
A device according to Claim 1, in which the rotation support is interposed between the cam and the head.
A device according to Claim 1 or Claim 2 in which the cam shaft comprises a first rotation-limiting tooth for interfering with second and third teeth of the housing half-shells.
A device according to Claim 1, Claim 2 or Claim 3, comprising resilient means for biasing the cam in a stable manner into one of two predetermined angular positions.
A device according to any one of the preceding claims, comprising an indicator flag coupled kinematically to the first auxiliary contact and facing a window opening in the front face to indicate the position of the first auxiliary contact.
A device according to Claim 5, comprising a test button acting on the release device and accessible from the front face.
A device according to any one of the preceding claims, comprising a second auxiliary switching contact which is operative during switching mirroring the switching of the contact of the circuit-breaker.
A device according to Claim 7, comprising a delay mechanism for delaying the switching of the first auxiliary contact relative to the switching of the second auxiliary contact upon the release of the setting device.