Electrical rotary switch with quick-coupling knob

Abstract

An electrical rotary switch comprising means (9) for the quick engagement and release of an actuation knob (6) with respect to an actuation element (5, 105) of the switching box of the switch. The quick engagement and release means comprise a pin (10) which transversely protrudes from an external portion of the actuation element (5, 105) and a sliding element (11) which is located inside the knob (6) and is elastically loaded toward the coupling seat (7) of the knob (6) in which the actuation element (5, 105) is inserted and can transversely slide with respect to the seat (7). The sliding element (11) is provided with a lateral recess (17) adapted to at least partially accommodate the pin (10) to removably lock the knob on the actuation element (5, 105).

Description

[0001] ELECTRICAL ROTARY SWITCH WITH QUICK-COUPLING KNOB

[0002] The present invention relates to an electrical rotary switch, more particularly a DC disconnector or cam switch, with a quick-coupling knob.

[0003] As is known, rotary switches are used to set electrical connection states by virtue of a mechanical rotary motion, which can simultaneously change the connection state of one or more circuits. Rotary switches can be single-pole or multipolar.

[0004] In a photovoltaic system, for example, the photovoltaic cells, the photovoltaic modules or panels comprising said cells, as well as the groups of these photovoltaic modules or panels, can be electrically uncoupled (or “disconnected”) from the inverters by means of rotary switches commonly termed “DC disconnectors” or, more simply, “disconnectors.”

[0005] Some disconnectors of a known type are described in EP2853012B1.

[0006] Disconnectors of the known type are generally constituted by a stack of modular contact boxes, topped by a snap-action switching box, which in turn is actuated by a spring-loaded loading spindle.

[0007] A profiled actuation rod, adapted to be engaged with an actuation knob, protrudes from the loading spindle. The actuation knob is external to the disconnector and has a profiled hole shaped complementarily with respect to the actuation rod.

[0008] In this way, the rotary actuation imparted to the knob is transferred to the actuation rod by means of the shape mating between the actuation rod and the hole in the knob.

[0009] Another type of rotary switch is the cam switch, known for example from US4724287.

[0010] Cam switches typically comprise one or more modular contact boxes stacked on top of each other and topped by a snap-action switching box. Each contact box comprises two or more pairs of fixed contacts and movable contacts designed to act on the fixed contacts to selectively close or open the electrical circuits connected to the pairs of fixed contacts. The electrical connections are actuated by an actuation shaft which rotatably engages all the contact boxes and can assume preset angular positions set by the snap-action switching box. The actuation shaft is provided with a plurality of cams, each of which is associated with a respective contact box to produce, as a result of a rotation of the actuation shaft about its own axis, a translation of the movable contacts of that box, in antagonism with contrast springs that act on the movable contacts.

[0011] A screw directed radially with respect to the axis of rotation of the rod and accessible from one side of the actuation knob is usually used to fix the knob axially to the disconnector actuation rod.

[0012] In other rotary switches, too, a screw is used for fixing the knob and, for example in the case of cam switches, can be directed radially or axially with respect to the actuation shaft.

[0013] Electrical rotary switches of the known type are not without drawbacks, among which is the fact that, if the knob needs to be replaced, there is not always sufficient space around the switch (in particular, the DC disconnector) to insert a screwdriver in a direction which is radial to the actuation rod in order to turn the screw and allow (re)fixing or disassembly of the actuation knob with respect to the actuation rod.

[0014] The use of the screw for fixing the knob is, however, disadvantageous because, especially in some fields such as railways, the rotary switch is subject to vibrations that can loosen the screw and thus force frequent interventions to restore the fixing of the knob.

[0015] The aim of the present invention is to provide an electrical rotary switch, in particular a DC disconnector or a cam switch, capable of obviating the drawbacks noted above.

[0016] Within this aim, an object of the present invention is to provide an electrical rotary switch, in particular a DC disconnector or cam switch, that makes the fixing of the knob to the actuation rod or shaft more stable.

[0017] A further object of the invention is to avoid screw means for fixing the knob to the actuation element of an electrical rotary switch.

[0018] A still further object of the invention is to provide an electrical rotary switch, in particular a DC disconnector or cam switch, in which the actuation knob of the snap-action switching box can be quickly installed or replaced.

[0019] Another object of the present invention is to provide an electrical rotary switch, in particular a DC disconnector or cam switch, that allows to fix the knob to the actuation rod in an easily removable manner.

[0020] Moreover, an object of the present invention is to overcome the drawbacks of the background art in a manner that is alternative to any existing solutions.

[0021] Not least object of the invention is to provide an electrical rotary switch that is highly reliable, relatively easy to provide and at competitive costs.

[0022] This aim and these and other objects that will become better apparent hereinafter are achieved by an electrical rotary switch according to claim 1 , optionally provided with the characteristics of one or more of the dependent claims.

[0023] Further characteristics and advantages of the invention will become better apparent from the description of preferred, but not exclusive, embodiments of the electrical rotary switch according to the invention, illustrated by way of non-limiting example with the aid of the accompanying drawings, wherein:

[0024] Figure 1 is a perspective view of a disconnector according to the invention;

[0025] Figure 2 is a perspective view of the disconnector shown in Figure 1 with the actuation knob disassembled;

[0026] Figures 3 to 6 are four sectional views, illustrating sequentially the operations for assembly of the actuation knob to the actuation rod of the disconnector shown in Figures 1 and 2; Figures 7 to 10 are four sectional views, illustrating sequentially the operations for disassembly of the actuation knob from the actuation rod of the disconnector shown in Figures 1 and 2;

[0027] Figure 11 is an exploded view of the knob of the disconnector of the preceding figures;

[0028] Figure 12 is a bottom view of the knob of the disconnector of the preceding figures;

[0029] Figure 13 is a perspective view of a first cam switch according to the invention, with the actuation knob disassembled;

[0030] Figure 14 is a perspective view of a second cam switch according to the invention.

[0031] With reference to the figures, a DC disconnector according to the invention, particularly for photovoltaic applications, is designated by the reference numeral 1 and comprises one or more modular contact boxes 2 stacked one on top of the other and topped by a snap-action switching box 3, from which a rod-like actuation element protrudes which is provided with an actuation knob 6.

[0032] In greater detail, the snap-action switching box 3 comprises a loading spindle 22 and a torsion spring 23 adapted to be loaded by a rotation of the loading spindle about a rotation axis 4.

[0033] Each modular contact box 2 is per se of a known type, for example from EP2853012B1. In particular, each modular contact box 2 has a movable contact, which can rotate about the axis of rotation 4, and two fixed contacts, which can be mutually electrically connected by the rotatable contact or electrically isolated, depending on the angular position of the rotatable contact about the axis of rotation 4. The rotatable contacts of the modular contact boxes 2 (not shown) are mechanically connected to each other (for example, by a single actuation shaft) so that they rotate simultaneously about the axis of rotation 4.

[0034] The loading spindle 22 is fixed to an actuation rod 5, which constitutes the rod-like actuation element of the switching box 3 and is partially inserted into the loading spindle 22 and partially protrudes outside the snap-acting switching box 3 along the axis of rotation 4. The rotation of the loading spindle 22 via the actuation rod 5 loads the torsion spring 23 associated with the loading spindle 22 and, once a certain angle of rotation has been exceeded, the elastic force accumulated by said spring 23 is released onto an indexing element (not shown) which is rigidly connected to the rotatable contacts. Consequently, these rotatable contacts rotate simultaneously with a snap action into an angular position for electrical connection, or electrical isolation, of the fixed contacts of the modular contact boxes 2.

[0035] The actuation rod 5 is integral in rotation with the loading spindle 22 about the axis of rotation 4 and is contoured for its shape mating with the actuation knob 6 at a coupling seat 7 inside the actuation knob 6. The coupling seat 7 is open toward the base 8 of the actuation knob 6 and extends axially inside said knob.

[0036] The coupling seat 7 is a substantially parallelepiped channel that runs centrally through the actuation knob 6 starting from its base 8. The coupling seat 7 has a longitudinal opening 71 whose width is less than that of the channel, so as to leave two parallel shoulders 72 along the opening 71 which are adapted to maintain the shape mating of the coupling seat 7 with the actuation rod 5.

[0037] In the above embodiment, the actuation rod 5 is a bar having a substantially square cross-section.

[0038] According to the invention, means 9 for the quick engagement and release of the actuation knob 6 with respect to the actuation rod 5 are provided.

[0039] More specifically, the quick engagement and release means 9 comprise a pin 10 which is fixed to the actuation rod 5 at its external portion with respect to the snap-action switching box 3. The pin 10 protrudes radially with respect to the rotation axis 4. The pin 10 may be cylindrical with a circular cross-section and is adapted to pass through, and translate along, the longitudinal opening 71 of the coupling seat 7 when the actuation rod 5 slides in the seat 7 in the steps of assembling or disassembling the knob 6 with respect to the disconnector 1.

[0040] Moreover, the quick engagement and release means 9 comprise a sliding element 11 , arranged inside the actuation knob 6 and having a lateral profile 12 that is substantially complementary to the lateral profile of the outer portion of the actuation rod 5 on the side from which the pin 10 protrudes. In particular, the sliding element 11 comprises a lateral recess 17 the shape of which is adapted to at least partially arrange the pin 10 and to prevent relative movement between the sliding element 11 and the pin 10 in the direction of the axis of rotation 4. In practice, the thickness of the lateral recess 17 (in the axial direction) is substantially equal to the diameter of the pin 10.

[0041] The sliding element 11 can slide inside the actuation knob 6 in a transverse direction with respect to the longitudinal axis of the coupling seat 7 (which, in use, coincides with the axis of rotation 4). Moreover, the sliding element 11 is elastically loaded toward the coupling seat 7 by virtue of elastic means, in particular a compression spring 21, which elastically oppose a sliding of the sliding element 11 away from the coupling seat 7.

[0042] The sliding element 11 is slidingly arranged in the actuation knob 6 within a sliding slot 18 oriented radially with respect to the axis of rotation 4. The slot 18 transversely extends from the coupling seat 7 and is advantageously open in a radial direction so as to allow the partial protrusion of the sliding element 11 from the knob when it is in the release position. By virtue of this protrusion, a visual indication of a possible incomplete coupling condition between the knob 6 and the actuation rod 5 is provided.

[0043] Optionally, for the purpose of guiding or limiting its axial movements, the sliding element 11 may have one or more lateral rails 25 adapted to engage one or more corresponding guides 26 which are internal to said slot 18.

[0044] The compression spring 21 may be a helical spring arranged in a notch-like seat 28 of the sliding element 11 that is provided with two mutually opposite teeth 29a-29b for supporting said spring. The diameter of the helical spring 21 is larger than the thickness of the sliding element 11 around the notch-like seat 28, so that the axial end of the spring 21 that is farthest from the coupling seat 7 can abut against a contrast wall 19 formed by the slot 18 in the actuation knob 6 and crossed by the tooth 29b that is radially farthest from the coupling seat 7.

[0045] The sliding element 11 is movable in contrast to and by virtue of the action of the compression spring 21, along a direction which is parallel to the pin 10, between an engagement position and a release position. In the engagement position, the sliding element 11 is adjacent to the longitudinal opening 71 of the coupling seat 7, so that it can accommodate the pin 10 in the recess 17 when the actuation rod 5 is inserted in the coupling seat 7.

[0046] In the engagement position, the longitudinal opening 71 of the coupling seat 7 is preferably crossed radially by an upper nose 24 of the sliding element 11 , which thus occupies a portion of the internal volume of the coupling seat 7.

[0047] In the release position, the sliding element 11 is radially translated with respect to the engagement position, so as to allow relative axial movement between the actuation knob 6 and the actuation rod 5 and, consequently, associate or disassociate the actuation knob 6 with respect to the actuation rod 5.

[0048] Advantageously, the lateral profile 12 of the sliding element 11 comprises a first inclined plane 13 between the recess 17 and the base 27 of the sliding element 11. The surface of the first inclined plane 13 moves away from the coupling seat 7 as it moves away from the recess 17 along the lateral profile 12.

[0049] The first inclined plane 13 is adapted to engage the pin 10 during insertion of the actuation rod 5 in the coupling seat 7, to allow a radial translation of the sliding element 11 toward the release position. The first inclined plane 13, in practice, allows to define a component of the applied force (via the pin 10 during insertion of the rod 5 into the seat 7) that is parallel to the sliding direction of the sliding element 11 and opposes the elastic force applied by the compression spring 21.

[0050] Equally advantageously, the lateral profile 12 of the sliding element 11 comprises a second inclined plane 14 formed on the upper nose 24 of the sliding element 11 and located proximate to the top of the actuation knob 6, axially opposite to the base 8 of the knob 6. The second inclined plane 14 is arranged, in the engagement position, at an access 15 which is formed on the actuation knob 6 and communicates with the channel that forms the coupling seat 7. In particular, the access 15 is an opening that is accessible from outside the knob and preferably crossed by the rotation axis 4.

[0051] The second inclined plane 14 is exposed toward the access 15 and is a guide adapted to engage with an external tool 16, for example a screwdriver bit or other rod-like element, appropriately inserted into the access 15 for the translation of the sliding element 11 from the engagement position to the release position when the knob 6 is fixed on the actuation rod 5. The knob 6 can thus be disassociated from the actuation rod 5 by moving it away from the latter along the axis of rotation 4.

[0052] Conveniently, the recess 17 is arranged between the two inclined planes 13 and 14.

[0053] Equally conveniently, the actuation rod 5 is hollow at least in the part exposed toward the knob 6, so that the tip of the external tool 16 can optionally be accommodated temporarily and the sliding element 11 can be kept in the release position (by virtue of the thickness of the tool 16, in particular of the screwdriver shank) during the removal of the actuation knob 6 from the actuation rod 5.

[0054] In other embodiments, shown in Figures 13 and 14, respectively, the actuation knob 6 (identical to the one described above) is coupled to the rod-like actuation element 105 of a cam switch 100 or 100'. Said switch 100 or 100' comprises one or more modular contact boxes 102 or 102' stacked on top of each other and topped by a switching box 103 or 103', respectively. The switching box 103, 103' comprises a rod-like actuation element 105 (not visible in Figure 14) whose rotation about its own axis 4 can be actuated from outside the switch 100, 100' via the knob 6.

[0055] Each modular contact box 102, 102' of the switch 100, 100' comprises movable (for example, translatable) contacts and two or more pairs of fixed contacts that can be electrically connected according to the position of the movable contacts.

[0056] The electrical connections can be set by an actuation shaft (which can be monolithic or composed of separate parts rigidly connected to each other in the axial direction) that engages rotatably all the contact boxes 102, 102' and can assume preset angular positions about its axis of rotation 4 which can be conferred by means of the rotation of the actuation element 105 of the switching box 103, 103', in particular via the knob 6 coupled to the actuation element. The actuation shaft of the switch 100, 100' is provided with a plurality of cams (not visible in Figures 13-14), each of which is associated with a respective contact box 102 or 102' to bring about, as a result of a rotation of the actuation shaft about its own axis, a movement of the movable contacts of that contact box 102 or 102' (for example, a translation of the movable contacts), in antagonism with contrast springs that act on the movable contacts.

[0057] The actuation element 105 accessible from the outside of the switch 100, 100' may be an end of the actuation shaft of the switch 100, 100' (which therefore also passes through the switching box 103, 103') or may be an actuation spindle coupled to the actuation shaft. In either case, the part of the actuation element 105 that protrudes outside the switching box 103 (or 103') has a configuration that is substantially identical to that of the external part of the actuation rod 5 of the disconnector 1, i.e., it is prismatic in shape (to fit with shape mating in the coupling seat 7 of the knob 6) and comprises a radially protruding pin 10 (for coupling with the recess 17 of the sliding element 11).

[0058] The operation of the electrical rotary switches according to the invention can be easily understood from the above.

[0059] With reference to Figures 3 to 6, once the disconnector 1 has been assembled, connected and positioned, in order to be able to assemble the actuation knob 6 it is sufficient to orient and align it so that the pin 10 is on the same plane on which the sliding element 11 translates, which can be identified by virtue of the fact that the slot 18 is advantageously open.

[0060] Then, by pressing the actuation knob 6 on the actuation rod 5, with the penetration of the latter in the coupling seat 7 and by virtue of the first inclined plane 13, the pin 10 pushes the sliding element 11 to radially translate from its engagement position to its disengagement position, in which the sliding element radially protrudes out of the slot 18 and, consequently, out of the knob 6 (as shown in Figure 5).

[0061] In its advancement along the axis 4, when the pin reaches the recess 17, thanks to the intervention of the elastic means 21 the sliding element 11 snaps and returns to its engagement position, rendering the actuation knob 6 integral with the actuation rod 5 with both rotation and translation. In the correctly reached engaged position, the sliding element 11 returns completely inside the slot 18 without protruding out of the knob anymore.

[0062] Conversely, with reference to Figures 7-10, by pushing the tip of the external tool 16 (for example a screwdriver) in a substantially axial direction through the access 15, said tip interferes with the second inclined plane 14 of the sliding element 11 in order to wedge itself between the nose 24 and a wall of the coupling seat 7 that is opposite to the longitudinal opening 71, thus moving the sliding element 11 away from the axis of rotation 4 (optionally with a lever-like movement of the tool 16) and freeing the pin 10 from the recess 17. By pushing the external tool 16 further, all the way into the actuation rod 5, the sliding element 11 can be kept in the release position while manually moving the knob 6 away from the actuation rod 5.

[0063] The operation of the invention in the case of the switch 100 or 100' is fully similar, since the knob 6 and the configuration of the actuation element 105 coupled to it are identical with respect to the knob 6 of the disconnector 1 and the configuration of the actuation rod 5.

[0064] In practice it has been found that the electrical rotary switch according to the present invention achieves the intended aim and objects.

[0065] The rotary switch thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the accompanying claims.

[0066] All the details may furthermore be replaced with other technically equivalent elements.

[0067] In practice, the materials used, so long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art.

[0068] The disclosures in Italian Patent Application No. 102024000004678 from which this application claims priority are incorporated herein by reference.

[0069] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

CLAIMS1. An electrical rotary switch (1, 100, 100') comprising one or more modular contact boxes (2, 102, 102') topped by a switching box (3, 103, 103'), each modular contact box comprising at least one movable electrical contact and a plurality of fixed electrical contacts, said switching box comprising a rod-like actuation element (5, 105) which can rotate about a rotation axis (4) and protrudes partially outside of said switching box (3, 103, 103') along said rotation axis (4), said actuation element (5) being adapted to cause, with a rotation thereof about the rotation axis (4), a movement of said movable electrical contacts with respect to the respective fixed electrical contacts, said actuation element (5, 105) being detachably fixed to an actuation knob (6) at a coupling seat (7) which is formed inside said actuation knob (6) and is open toward a base (8) of the actuation knob (6) to arrange a portion of said actuation element (5, 105) which is external to said switching box (3, 103, 103'); characterized in that the electrical rotary switch (1, 100, 100') comprises means for the quick engagement and release (9) of said actuation knob (6) with respect to said actuation element (5, 105), said quick engagement and release means comprising:- a pin (10) which transversely protrudes from said external portion of the actuation element (5, 105) and- a sliding element (11) which can move inside said actuation knob (6) and is provided with a lateral recess (17) adapted to at least partially accommodate said pin (10); wherein said coupling seat (7) comprises a lateral opening (71) directed toward said sliding element; and wherein said sliding element (11) is elastically loaded toward said coupling seat (7) and can transversely slide with respect to said coupling seat (7) between an engagement position, in which said sliding element (11) is close to said coupling seat (7) in order to receive said pin (10) in therecess (17) when said actuation element (5, 105) is inserted in said coupling seat (7) and in order to lock axially the knob (6) on the actuation element (5, 105), and a release position, in which the sliding element (11) is radially translated with respect to said engagement position, so as to allow a relative axial motion between said actuation knob (6) and said actuation element (5, 105).

2. The switch (1, 100, 100') according to claim 1, characterized in that said sliding element (11) comprises a lateral profile (12) which faces said lateral opening (71) of the coupling seat (7) and on which said recess (17) is obtained, said lateral profile (12) comprising furthermore a first inclined plane (13) between said recess (17) and a base (27) of said sliding element (11), said first inclined plane (13) being adapted to engage said pin (10) during the insertion of said actuation element (5, 105) in said coupling seat (7), so as to radially translate said sliding element (11) toward said release position.

3. The switch (1, 100, 100') according to claim 1 or 2, characterized in that said actuation knob (6) comprises an axial access (15) on the opposite side with respect to the base (8) of the knob and through which said sliding element is engageable from outside the knob by means of an external rodlike tool (16), so as to translate, from outside the knob, the sliding element (11) toward said release position.

4. The switch (1, 100, 100') according to claim 3, wherein said lateral profile (12) of said sliding element (11) comprises a second inclined plane (14) which is formed proximate to the top of said actuation knob (6), on the opposite side with respect to said base (8) and at said access (15) in order to provide a guiding surface for said external tool (16).

5. The switch (1, 100, 100') according to one or more of the preceding claims, characterized in that said sliding element (11) is slidingly arranged in a sliding slot (18) which transversely extends from said coupling seat (7) and is internal to the actuation knob (6).

6. The switch (1, 100, 100') according to claim 5, wherein said slot (18) is laterally open toward the outside of the knob (6) so as to allow the partial exit of said sliding element (11) from said knob (6) in said release position.

7. The switch (1, 100, 100') according to claim 5 or 6, wherein said sliding element (11) is provided with one or more lateral rails (25) adapted to engage one or more corresponding guides (26) which are internal to said slot (18).

8. The switch (1, 100, 100') according to one or more of the preceding claims, characterized in that it comprises a compression spring (21) interposed between said sliding element (11) and a contrast wall (19) which is internal to said actuation knob (6), in order to elastically load said sliding element (11) toward said coupling seat (7).

9. The switch (1, 100, 100') according to one or more of the preceding claims, characterized in that it is a disconnector (1), particularly for photovoltaic applications.

10. The switch (1, 100, 100') according to one or more of claims 1-8, characterized in that it is a cam switch (100, 100').

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