The present disclosure relates to an emergency opening device suitable for manually opening a switching device, in particular a contactor.

In medium voltage applications it is known the use of a multi-phase contactor for carrying and breaking electrical currents. Such a contactor is configured for switching on/off, for example, electric motors in several fields, such as in industry, service sector, marine sector, and other difficult environments. The multi-phase contactor comprises, for each phase, a fixed contact and a movable contact which can be positioned between an open position, in which it is operatively separated from the fixed contact, and a closed position, in which it is operatively connected to the fixed contact.

The movable contacts are actuated to move between the open and closed positions by means of an electromagnetic actuator which is fed by an auxiliary power supply. A number of important conditions are required to be satisfied in order to guarantee the proper functional performances during service life in electrical networks; in particular, switching off manoeuvres should be carried out in due time, normally as quickly as possible, in order to prevent possible damages to the equipment. If, under fault conditions, the auxiliary power supply is absent or when the electromagnetic actuator is malfunctioning for any reasons, for instance due to breakage of any components, manual opening operations are necessarily to be performed through a manually intervention on a shifting-mechanism of the electromagnetic actuator which is mechanically linked to the movable contacts. Before a manually intervention on said shifting-mechanism, it is required, at first, to switch off the medium voltage in order to avoid damages to the loads fed or to the contactor itself. Such a preliminary switching off the medium voltage is important and highly recommended inasmuch as the manual opening speed of the operator may be not sufficiently adequate for avoiding, in a reliable way, the rise of voltaic arcs in the contacts, in other words, the operator may not be able to perform the opening operations within determined required time limits. Nevertheless, the precautionary switching off of the medium voltage implies putting out of service various loads, with the evident economical drawbacks that follow.

In order to get out of this drawback, a known contactor has been proposed into which a permanent internal manual opening device is incorporated which can be operated by an operator for manually opening the electromagnetic actuator with a desired speed without putting the loads out of service.

In particular, the internal manual opening device intervenes on the abovementioned shifting-mechanism of the electromagnetic actuator which is mechanically linked to the movable contacts.

Such an internal manual opening device comprises a kinematic mechanism having an operating shaft, a first pivotal lever movable by the latter, a second pivotal lever movable by the first pivotal lever for acting on the above mentioned shifting-mechanism for opening the electromagnetic actuator, and a suitable cam-step-profile for blocking and enabling a movement of the second lever.

Heavy internal structural modifications have been carried out to the contactor in order to make it adapted to internally and permanently house such a manual opening device. Therefore, if it is desired to provide old type contactors currently already in service with this manual opening device, a particular retrofitting procedure has to be carried out for properly modifying the internal structure of such contactors so that the manual opening device can be permanently fit therein. Obviously, such an adapting procedure implies an undesired interruption of the service duty that should be took into account.

Although such an internal manual opening device performs in a quite satisfying way, there is still room for further improvements. In particular, it would be desirable to provide a technical solution which is ready to be easily used by an operator for manually opening with a desired speed an old type contactor without having to put the loads out of service, i.e. while the medium voltage is present and the loads are fed. It would be also desirable such a technical solution to be at same time cheap, safe, reliable, and structurally simple.

This is achieved by an emergency opening device as defined in the appended claims and described hereinafter in details. According to the present disclosure, there is provided an emergency opening device suitable for manually opening a switching device comprising:

- striking rod means for transmitting an opening-striking- force to an electromagnetic actuator which is operatively connected to electrical contacts of said switching device; a guiding-housing suitable for being placed on an external portion of a casing in which said switching device is housed, said guiding-housing being configured for slidably housing and guiding, along an operating direction, said striking rod means,

- energy-storing-propelling-means for propelling said striking rod means upon an external-triggering-command of an operator in order to impart said opening-striking-force to said electromagnetic actuator, said energy-storing- propelling-means being configured for imparting to said striking rod means along said operating direction a rectilinear snap movement having at least a kinematic parameter which is independent from said external-triggering- command.

The present disclosure encompasses also an electric switchgear, equivalently called with the term panel or cabinet or switchboard, including a switching device, in particular a contactor and an emergency opening device as defined in the related appended claims and described herein. Characteristics and advantages of the present disclosure will result from the description and from claims.

The present disclosure can be better understood and implemented with reference to the attached drawings that illustrate an embodiment thereof by way of a non-limiting example, in which:

Figures 1 and 2 are a perspective view and a cut away view respectively of an emergency opening device according to the present disclosure;

Figure 3 is an exploded view of the emergency opening device of Figure 1;

Figure 4 is a perspective view of a version of the emergency opening device according to the present disclosure;

Figures 5 and 6 are longitudinal cross-section views of the of the emergency opening device in a loaded configuration and in a unloaded configuration respectively;

Figures 7 and 8 are different perspective views of the emergency opening device temporarily connected to a door of a switchgear;

Figures 9 and 10 show a version in which the emergency opening device includes a removable extension element for allowing functioning of the emergency opening device in test- conditions .

With reference to the attached Figures, an emergency opening device 1 is shown, which is suitable for manually opening a switching device, in particular a contactor included in a medium voltage switchgear, where, for the purposes of the present application, the term medium voltage refers to applications in the range from lkV up to some tens of kV, e.g. 52 kV.

In particular, the emergency opening device 1 is of a portable type and can be easily handled by an operator, in an emergency situation, for manually opening a contactor without having to switch off the medium voltage.

In particular, the emergency opening device 1 mechanically acts on an electromagnetic actuator, more precisely on a shifting-mechanism of the latter which is mechanically linked to the movable electrical contacts of the contactor.

The emergency opening device 1 comprises a striking-rod- element 5 which is suitable for transmitting an opening- striking-force to such a shifting mechanism so as to separate the movable contacts from the respective fixed contacts.

The emergency opening device 1 comprises a guiding-housing 2 for slidably housing and guiding, along an operating direction 6, the striking-rod-element 5.

In the exemplary non-limiting embodiments herein illustrated, the striking-rod-element 5, includes a first rod part 7, intended to at least partially protrude out of the guiding- housing 2 for going into contact with the shifting mechanism, and a second rod part 8, which, during functioning, substantially remains inside the guiding-housing 2. The first rod part 7 and the second rod part 8 are mutually fixed trough a threaded coupling so as to define a longitudinal axis 11. However, the striking-rod-element 5 can also be realized as a single piece element.

The guiding-housing 2 is defined by a first guiding-housing part 3 and a second guiding-housing part 4 which are mutually connected and which define respective chambers, in particular an energy-storing-chamber 15 and a retaining-release-chamber 16, better described later on. The second guiding-housing part 4 is delimited by a wall which defines a handle-portion 17 for an operator.

In an approximately central zone of the striking-rod-element 5, in particular on the second rod part 8, there is defined a stem portion 9 which is delimited on one end by a flange- portion 10 radially protruding from the striking-rod-element 5. In particular, the flange-portion 10 is integrally obtained on one end of the first rod part 7 and is intended to be movably housed inside the first guiding-housing-part 3. The flange portion 10 is shaped for abutting against an internal stop surface 12 which is provided on a wall of the first guiding-housing-part 3 lying transversely to the longitudinal axis 11. The emergency opening device 1 comprises energy-storing- propelling-means 13 configured for storing a set mechanical elastic energy and for releasing this energy, upon an external-triggering-command imparted for instance by an operator, for propelling the striking rod element 5 towards the above mentioned shifting mechanism so as to impart to the latter the opening striking force which is required for moving with the proper speed the movable contacts. In particular, the energy-storing-propelling-means 13 are configured for imparting to the striking rod element 5 a rectilinear snap movement, along the operating direction 6, having one or more kinematic parameters which are independent from the external-triggering-command . In particular, the kinematic parameters comprise the speed at which the striking rod element 5 is moved. A further kinematic parameter comprises the acceleration imparted to the striking rod element 5.

The energy-storing-propelling-means, in the embodiment here described, comprise a compression spring 13 positioned around the stem portion 9 and interposed between the flange-portion 10 and a resting sleeve element 14. The resting sleeve element 14 is placed inside the first guiding-housing part 3 in a stationary position at an end opposite to the internal stop surface 12. An axial opening is obtained in the resting sleeve element 14 trough which the striking-rod-element 5 is relatively and coaxially slidable.

The flange-portion 10 is configured for being movable inside the first guiding housing 3 from a first position, in which the compression spring 13 is in a loaded, i.e. compressed, configuration, and a second position in which the flange- portion 10 abuts against the internal stop surface 12 when the compression spring 13 is in a, at least partially, released configuration.

Therefore, the mechanical elastic energy stored in the compression spring 13 inside the first-guiding-housing 3 - which thus acts as an energy-storing-chamber - is intended to be transformed in a rather impulsive fast movement of the striking rod element 5.

The properties/features of the compression spring 13 and of the striking rod element 5, e.g. physical, mechanical, geometrical, such as material, dimensions, stiffness, number of turns, are chosen so as to obtain a movement of the striking rod element 5 with desired prefixed kinematic parameters, such as speed, acceleration, and preferably they are repeatedly constant during service life.

Owing to such a structural configuration, the rectilinear snap movement of the striking rod element 5 is always the same and is totally independent from the manual actuation speed of the operator which handles the emergency opening device 1, and preferably is substantially the same.

The emergency opening device 1 comprises a retaining- triggering-unit 18 configured for retaining the compression spring 13 in the loaded compressed configuration and for leaving the compression spring 13 expand when the operator imparts an external-triggering-command for generating the above mentioned rectilinear snap movement.

The retaining-triggering-unit 18 is partly housed in the retaining-release-chamber 16 defined by the second guiding- housing part 4. The retaining-triggering-unit 18 comprises a push pin element 19 extending and movable along a pushing direction 20, transversely to the longitudinal axis 11.

In particular, the push pin element 19 is movable from a retaining position, in which it holds the striking rod element 5 in the loaded compressed configuration, and a releasing position, in which it releases the striking rod element thus allowing the snap movement thereof.

An engaging opening 21 is obtained in the push pin element 19, through which a retainable portion 25 of the striking rod element 5, in particular of the second rod part 8, passes through and is relatively movable along the longitudinal axis 11.

The retaining-triggering-unit 18 comprises a retaining spring 23 which is placed around the push pin element 19 and interposed between the second guiding-housing part 4 and a push-head 24 of the push pin element 19. The retaining spring 23 is of the compression type and acts for urging the push- head 24 away from the second guiding-housing part 4, in particular tends to keep the push pin element 19 in the retaining position.

On the push pin element 19 there is defined a retaining part 22 which delimits the engaging opening 21. The retaining part 22 is shaped for engaging with an engaging groove 26 which is obtained on the retainable portion 25. In particular, the engaging groove 26 is obtained transversely around the striking rod element 5, as shown in Figures 6 and 3.

When the compression spring 13 is in the loaded compressed configuration, the retaining part 22 of the push pin element 19 engages with the engaging groove 26. A stable coupling of the engaging groove 26 with the retaining part 22 is guaranteed by the urging action of the retaining spring 23, which tends to project the push pin element 19 out of the retaining-release chamber 16, thus pressing the retaining part 22 against and inside the engaging groove 26. In this configuration, the striking rod element 5 is kept blocked and the compression spring 13 is not allowed to expand. Expansion of the compression spring 13, and therefore a snap movement of the striking rod element 5, is enabled only upon an external triggering command, i.e. when the operator pushes the push pin element 19 in the pushing direction 20, thus disengaging the retaining part 22 from the engaging groove 26. In this way the striking rod element 5 is released and left free to move under the action of the compression spring 13.

The snap movement of the striking rod is clearly independent from the manual external triggering command exerted by the operator on the retaining-triggering-unit 18, the snap movement being determined by the elastic features of the compression spring 13. In order to load the emergency opening device 1, i.e. in order to charge the compression spring 13, the operator may grasp the handle portion 17, lean a tip 28 of the striking rod element 5 against a fixed surface, for example against the floor, and press against the floor so as to introduce the first rod part 7 inside the first guiding housing part 3, thus compressing the compression spring 13. When the engaging groove 26 reaches the engaging opening 21 of the retaining- triggering-unit 18, the push pin element 19, under the action of the retaining spring 18, leaps to the retaining position and the retaining part 22 enters the engaging groove 26 and blocks the striking rod element 5. In this way, the emergency opening device 1 is ready to work. The operator may insert the tip 28 and a front end portion of the guiding-housing 2 inside an apposite connection-socket opening 29 which is provided on the casing of the switchgear. The connection- socket opening 29 can be shaped as a receiving-bush-element. In particular, the connection-socket 29 is mounted on a door 30 of a switchgear-casing, as shown in figures 7 and 8. The emergency opening device 1 can be connected to connection- socket 29 and can be operated when the door 30 is in a closed position, so as to enable the striking rod element 5 to reach the shifting mechanism of the electromagnetic actuator associated to the contactor which is housed in the casing. At this point, the operator can push the push pin element 19 for causing the opening of the electrical contacts of the contactor, and subsequently may remove the emergency opening device 1 e put it away.

For ensuring a temporary connection to the door 30 in a steady manner, the emergency opening device 1 may comprise suitable temporary coupling means. The temporary coupling means may comprise a threaded coupling portion provided on the front end of the first guiding housing part 3, shaped for coupling with a corresponding threaded zone suitably provided on the connection-socket 29 on the door 30. In a further version, shown in Figure 4, the temporary coupling means comprise a bayonet joint, including a first bayonet portion

31 which is fixed to the guiding housing 2 and is shaped for removably engaging with a stationary second bayonet portion

32 to be permanently provided on the connection socket 29. Other forms of temporary connection can be provided, for example a snap-quick-connection etc..

The emergency opening device 1 can be provided with a removable extension element 33 (shown in Figure 9) which is connectable to the front end portion of guiding-housing 2. In such an extended configuration or test-configuration of the device, the first bayonet portion 31 or other temporary coupling element, can be connected to the front end portion of the removable extension element 33. The removable extension element 33 allows the operator to perform some tests on the contactor. In particular, owing to the extended configuration, the emergency opening device 1 can operate when the contactor, supported by a slidable trolley, is pulled in a non-operative-extracted position in the casing of the switchgear. The removable extension element 33 acts as a spacing element and adjusts the correct relative position of the striking rod element 5 with respect to the shifting mechanism of the electromagnetic actuator provided on the contactor which is in the non-operative-extracted position. It has been described how, owing to the emergency opening device 1 of the disclosure, the intended aim of providing a simple and effective technical solution enabling to reliably open a switching device also in "on load" conditions has been achieved. In particular, the emergency opening device 1 proves to be very useful in connection with old type contactors which otherwise require to switch off the medium voltage before starting a manual opening manoeuvre.

Differently from the manual opening device of the prior art, the emergency opening device 1 according to the disclosure is not of an embedded type, but it is of a portable type, which can be handled and used by the operator in emergency situations . The emergency opening device 1 is susceptible of modifications or variations all within the scope of the inventive concept as defined by the appended claims and including any combination of the above described embodiments; any details may be replaced with technically equivalent elements. For example, instead of the compression spring, a pneumatic spring, or a tension spring suitably positioned, can be provided, etc.

One or more of the elements above described may be differently shaped and/or positioned, can be realized in one or more pieces or differently coupled or positioned, etcetera .

In practice, the materials, so long as they are compatible with the specific use, as well as the individual components, may be any according to the requirements and the state of the art .