DESCRIPTION

The present disclosure refers to the technical filed of electrical installations and, more specifically, relates to a push-button switch with fast wiring terminals comprising a protection device against the intrusion of dust and the like.

As is known, electric push-button appliances for the control and/or distribution of electricity, such as for example push-buttons or diverter switches, comprise a box-like body in electrically insulated material provided with an inner housing compartment for electromechanical mechanisms of the electric appliance. One example of the aforesaid appliances is represented by modular push- button switches or in general modular control devices, of domestic electricity grids.

The functioning of the aforesaid electrical appliances may be jeopardised by the unwanted intrusion of dust and similar particles inside the box-like body, such as for example granules of sand and particles of construction materials.

The unwanted intrusion of dust or particles in electrical appliances as described in the European patents EP 1866944 Bl and EP 2297759 Bl is particularly problematic because it can determine jamming of the control switch. In other types of electrical appliances such unwanted intrusion is in any case problematic because it may determine failure, poor performance or temporary malfunction.

The patent application WO2011/121625 describes an electrical appliance for the control and/or distribution of electricity provided with a protection device which is able to prevent the unwanted intrusion of dust or similar particles in a portion of the inner compartment of the electric appliance. The protective device comprises a tearable membrane attached to a diaphragm housed in the inner compartment of the electric appliance. The diaphragm defines two chambers in the compartment, one of which houses the screw interconnection terminals.

The object of the present disclosure is to make available a push button switch which is provided with suitable expedients adapted to prevent or reduce the unwanted intrusion of dust or particles in the portion of the inner compartment which houses the sliding guide of the push button and at the same time which can be simply and rapidly connected to the electricity grid.

Such object is achieved by a push-button switch as defined in general in Claim 1. Preferred or advantageous embodiments of the aforesaid appliance are defined in the appended dependent claims. The invention will be clearer to understand from the detailed description given below, by way of a non- limiting example, of a specific embodiment, with reference to the appended drawings, wherein:

- figure 1 is a perspective view of one embodiment of a push-button switch, in which the front side of the switch is visible;

- figure 2 is a perspective view of the switch in figure 1, in which the rear side of the switch is visible;

- figure 3 is a perspective view in three detached parts of the switch in figure 1, in which one of the three parts is shown in partial cross-section;

- figure 4 is a perspective view of the three parts in figure 3, in which the three parts are shown in an assembled configuration;

- figure 5 is a perspective view in an assembled configuration of two of the parts shown in figure 3;

-figure 6 is a side plan view of the switch in figure 1;

- figure 7 is a cross-section view of the switch in figure 1, along the line A-A indicated in figure 6;

- figure 8 is a cross-section view of the switch in figure 1, along the line B-B indicated in figure 6;

-figure 9 is a rear plan view of the switch in figure 1;

- figure 10 is a cross-section plan view of the switch in figure 1, along the line C-C indicated in figure 9;

-figure 11 is a side plan view of the switch in figure 1;

figure 12 is a cross-section plan view of the switch in figure 1, along the line D-D indicated in figure 11;

- figure 13 is a perspective view from above of an anti-dust protection device comprised in the switch in figure 1; and

- figure 14 is a perspective view from below of the protection device in figure 13.

In the drawings, elements which are the same or similar will be indicated using the same reference numerals .

With reference to the appended drawings a non- limiting embodiment of a push-button switch is shown, globally denoted by reference numeral 1. In the particular example shown in the drawings and which will be described below, the push-button switch 1 is a modular switch, in other words destined to be installed on a support frame for mounting on a wall alongside other switches of the same type or in general other modular electric appliances, such as for example identical or similar switches, or electrical sockets. Switch is understood herein to mean any device which can be commanded to determine a circuit switching.

Hereinafter reference will be made, without by so doing introducing any limitation, to the case in which the electric appliance 1 is, as in the example shown in the drawings, a modular push-button switch.

The push-button switch 1 comprises a command button 12, 25, 27 and a sliding guide 26 adapted to allow the command button 12, 25, 27 to slide along a sliding direction. With reference to figure 12, in the particular example shown the command button 12, 25, 27 comprises a button 25, a counter-button 27 and a button-cover 12 suitable for coupling to the button 25 and essentially having an aesthetic finish function. The aforesaid elements of the command button 12, 25, 27 are integral with each other during the sliding of the button.

The push-button switch 1 comprises a first tubular casing 2 having side walls 6-9 adapted to define an inner compartment 3 containing the sliding guide 26. According to one embodiment, the first casing 2 is made in a electrical insulating material, for example of plastic and preferably of polycarbonate.

With reference to figure 2, according to one embodiment, the sliding guide of the push-button comprises a holding and guide frame 26 adapted to couple the command button 12, 25, 27 to the first casing 2. According to one embodiment, the holding and guide frame 26 is made according to the teaching of the patent EP 1866944. According to a possible alternative embodiment not shown in the figures, the sliding guide is made integrally with the first casing 2, for example in one or more of the side walls 6-9.

The first casing 2 is fitted with a counter frame 21 and a coupling collar 33 made in one piece with first casing 2.

The inner compartment 3 communicates with the outside of first casing 2 by means of a front aperture 23 (visible in figure 5) and by means of an opposite rear aperture 33 (visible in figure 3) .

According to one embodiment, in the inner compartment 3 of the first casing 2 mechanical command elements of the circuit switching are housed. In practice the first casing 2 acts as a support, housing and attachment element of the command element of the circuit switching of the push-button switch 1. In the example described, such command elements are configured to move a pivoting switching element 10 adapted to establish electrical connections, which in the specific example, takes the form of a pivoting metallic jumper 10. The pivoting metallic jumper 10 is such as to be able to be moved ^' in rotation so as to establish/interrupt electric connections between two fixed contact elements 101, 102 (visible in figure 12) .

With reference to figure 12, according to one embodiment, the mechanical command elements of the switching circuit preferably comprise a switching command mechanism comprising a pivoting command element 28. Such pivoting command element 28 comprises a cursor 29 adapted to slide on the pivoting switching element 10 to determine the rotation thereof. The pivoting command element 28 is preferably made according to the description in the European patent EP 1584096 arid/or in the European patent EP 1866944. In the latter case the pivoting command element 28 is hinged to the holding and guide frame 26 so as to pivot.

According to one embodiment, the push-button switch 1 comprises at least one elastic element operatively positioned between the counter frame 21 and the push ^¬ button 12, 25, 27 which acts as a return element of the push-button. For example, a pair of return springs 24, positioned between the counter frame 21 and the push ^¬ button are provided, only one of which is visible in figure 3. With reference to figure 12, according to a preferred, non-limiting embodiment, the push-button switch 1 comprises an anti-jamming protection device 33, comprising a protective cap 33 adapted to occlude the front aperture 23 and for example made according to the teachings of the international patent application WO 2010/006867.

The push-button switch 1 further comprises a second casing 42, made in one piece separate from the first casing 2 and coupled thereto on the side opposite the front aperture 23. The second casing 42 houses and supports a plurality of fast wiring terminals. In the particular example shown the second casing 42 houses and supports three fast wiring terminals operable by means of respective levers 43 hinged to the second casing 42.

The second casing 42 has a plurality of through wiring openings 41 adapted to be crossed by electric conductors for the wiring of the switch 1 to an electricity grid, such as a domestic grid.

For the purposes of the present invention, a fast wiring terminal is understood to mean a wiring terminal adapted to stably constrain to the push-button switch 1 one or more electric conductors by means of one or more elastic elements 44 (visible in figures 10 and 12) for example in the form of leaf springs. The expression "stably constrain" is taken to mean that said fast wiring terminals are such as to maintain, in a detachable manner or not, a stable electric and mechanical connection between the wiring conductors and the push-button switch 1 after the engagement of such conductors at an appropriate depth, in the respective wiring apertures 41. The fast wiring terminals may be fitted, as in the example shown, with respective manual operating elements 43 (which in the example are operating levers 43) adapted to act on the elastic elements 44 or may be fully automatic in the sense that said manual operating elements 43 are not provided and the electromechanical connection is achieved by a mere forced engagement of the wiring terminal inside the wiring apertures 41.

With reference to figures 1 and 3, according to one embodiment, the push-button switch 1 comprises snap coupling elements 18, 19 adapted to couple the first 2 and the second casing 42 to each other. For example, apertures or recesses 18 in the side walls (in the example in the walls 6 and 8) of the first casing 2 and complementary attachment teeth 19 projecting from corresponding side walls of the second casing 42, or vice versa may be provided as snap coupling elements.

With reference to figure 2, according to one embodiment, one of the walls of the second casing 42 comprises an access aperture 45 to the inner compartment 3. The access aperture 45 is destined to be crossed by an accessory device (not shown in the figures) operatively couplable to the push-button switch 1 by engagement through the access aperture 45. The aforesaid engagement is for example an axial engagement where by axial direction a direction perpendicular to the plane which the access aperture 45 lies on is meant. According to one embodiment, the aforementioned accessory device is an LED back-lighting device. In alternative embodiments, the aforementioned accessory device is any device engageable in the access aperture 45, for example a micro-controller or a device for the control or monitoring of the status of the push-button switch 1.

The push-button switch 1, comprises an anti-dust protection device 50 comprising a gasket 5 positioned between the counter-frame 21 and the second casing 42 to isolate the inner compartment 3 from dust infiltration paths defined between the coupling collar 33 and the second casing 42. One particular example of an anti-dust protection device is clearly visible in figures 13 and 14.

Preferably, the anti-dust protection device 50 is made of relatively more elastic material, for example in rubber material, than the material which the first casing 2 is made of.

According to one embodiment, the anti-dust protection device 50 (and therefore also the gasket 5) is made in one piece with the first casing 2. For example, the anti-dust protection device 50 and the first casing 2 are made in two different materials by means of a dual- material moulding method, wherein preferably the first casing 2 is made of polycarbonate and the anti-dust protection device 50 in thermoplastic polyurethane.

According to an advantageous embodiment, the gasket

5 is a substantially annular shape and has an outer peripheral rim 59 which for its entire extension, or almost all its extension, is permanently attached, for example welded or glued, to the inner side of the side walls 6-9 of the first casing 2.

With reference to figure 4, in the case in which the push-button switch 1 is provided with a holding and guide frame 26, it may be provided that at least a portion 5a of the gasket 5 is positioned and compressed between the second casing 42 and the holding and guide frame 26. In conjunction with or separately from the embodiment just described, in a further embodiment, it may be provided that at least a portion 5b of the gasket 5 is positioned and compressed between the second casing 42 and the counter frame 21. According to an embodiment complying with the example shown in the drawings, in the case in which the fast wiring terminals comprise manually-operated levers 43 hinged to the second casing 42 at the hinging ends of said levers 43, it may advantageously be provided that the gasket 5 has recesses 51, visible in figure 2, suitable for housing said hinging ends.

In the embodiment in which the second casing 42 is provided with a through aperture 45, it may be provided, in compliance with the example shown in the drawings, that the anti-dust protection device 50 comprises a tearable membrane 55 facing the through aperture 45 to occlude the through aperture 45. In such embodiment, the tearable membrane 55 is made in one piece with the gasket 5.

According to an embodiment complying with the example shown in the drawings, both to achieve a more stable adhesion of the anti-dust protection device 50 to the first casing 2 and to close other possible infiltration channels of dust, it may be provided that the anti-dust protection device 50 has portions permanently attached (for example welded) to the side walls 6-9 of the first casing 2 and portions, such as for example the portion 53 visible in figures 3 and 7, permanently attached (for example welded) to the counter frame 21. With reference to figures 3, 5 and 13, in this last embodiment, one or more appendages 56 may be provided in the anti-dust protection device 50 projecting in relation to the gasket 5, which penetrate in recesses defined in the thickness of the counter frame 21. In the example shown, the anti- dust protection device 50 comprises two projecting appendages 56 which penetrate two stems 24 protruding from the counter frame 21 towards the push-button 12, 25, 27 and which are provided to keep the return springs 24 of the push-button 12, 15, 27 (of which only one is visible in figure 3) in position.

From the above description it may be seen how the push-button switch of the type described above fully achieves the intended objectives. It may in fact be noted how, advantageously, the provision of an anti-dust protection device 50 of the type described above allows a push-button switch with fast wiring terminals to avoid unwanted intrusions of particles of dust and the like through the coupling perimeter of the first and second casings. It may in addition be noted that the provision of said device has practically no impact on the overall dimensions of the push-button switch.

Obviously, a person skilled in the art may make numerous modifications and variations to the push-button switch described above so as to satisfy contingent and specific requirements, while remaining within the sphere of protection of the invention as defined by the following claims.