Patent Publication Number: US-7713072-B2

Title: Adapter device for a low voltage switching device

Description:
The present invention relates to an adapter device for electromechanical connection of a low voltage switching device of the withdrawable or plug-in type to a plurality of conductive bars. 
     It is known that low voltage switching devices (i.e. for applications with operating voltages up to 1000V AC/1500V DC), such as automatic circuit breakers, disconnectors and contactors, universally called switching devices and subsequently called switches for the sake of brevity, are devices conceived to permit correct operation of specific parts of electrical systems and of the loads installed. For example, automatic circuit breakers ensure that the rated current required can flow towards the various utilities, allowing correct connection and disconnection of the loads from the circuit and automatic sectioning of the circuit protected with respect to the electrical power source. Devices that allow abnormal operating conditions of a specific branch of a system to be recognized and consequent action to be taken with the opening of at least one of the switches present in the circuit are normally known as protective devices. The most widely used protective devices are of the thermal, magnetic, thermal magnetic or electronic type, also in combination with one another. 
     It is known that switches comprise a case, one or more electric poles, associated with each of which is at least one pair of contacts which can be coupled with and decoupled from each other. Prior art switches also comprise actuating means which cause the relative movement of the pairs of contacts so that they can assume at least a first coupling position (switch closed) and at least a separated position (switch open). 
     In common use, switches are installed in electrical systems through distribution boards. The use of appropriate distribution boards contributes toward ensuring long term correct functioning, safety conditions, practical and ergonomic use, and if possible also toward enhancing the appearance of the system. 
     In practical applications distribution boards can have a wide range of configurations, with particular reference to their different constructional and functional nature. For example, dimensions, materials used, fitting of inspection and or protective doors, type of auxiliary equipment and of conductors employed and reciprocal connections can all vary. The conductors present in a board to allow electrical connections can be classified as risers, horizontal bus bars, vertical bus bars, auxiliary power cables, cables for transmitting signals and controls. 
     Among prior art bus bars, those known as guide bars deserve particular attention; these are structured so as to comprise or integrate adapter devices suitable to allow rapid connection of switches. Said adapter devices conventionally have a dual mechanical and electrical function; in other words, they act as mechanical and electrical interface/connection elements between switch and board. 
     The choice of the type of switch to use, and in particular of the connection accessories and of the installation methods, must therefore be made taking account of the specific characteristics of the board in which the switch is used. To satisfy the various needs, three distinct modes of installing switches in boards are normally used. In particular, a first installation solution is known as fixed, in which the switch is mechanically constrained directly to support elements of the board, for example a mounting plate, and is directly connected to the conductors of a power supply circuit through its electrical terminals. A second installation solution is known as plug-in, in which a special adapter device is used, which is mechanically constrained to the board and is connected to the conductors of the supply circuit through its own electrical terminals; the switch is then mechanically inserted in this adapter device and is electrically connected thereto through the use of appropriate electrical terminals of the socket/plug type present on the switch and on the base. A third installation solution is known as withdrawable, and is a variant of the previous solution, and differs therefrom substantially only due to the fact that insertion of the switch in the fixed part takes place with the aid of specific guide and/or support means. 
     Generally, switches and adapter devices (either interface base or adapter) are provided with electrical connection terminals produced according to a basic standard configuration; however, not all installation solutions are suitable to establish electrical connections directly with the standard terminals of the switch or adapter. Therefore, in these cases it is necessary to install adaptation accessories such as additional or replacement electrical terminals which are configured differently according to the application required. These accessories are normally connected to the free ends of the electrodes of the switch. Just as the switches, the support bases must also comprise connection terminals suitable for the electrical system. In other words, when wishing to use plug-in or withdrawable versions of switches, it is necessary to provide adapters and to perform the following operations: mechanically install the adapter on the board; electrically connect it to the bus bar system; fit the switch to the adapter. 
     Various solutions have been proposed to overcome these prior art drawbacks. For example, the patent application WO 02054432 shows an adapter device comprising a body provided with a surface intended to be coupled with a corresponding coupling surface of a switch. The coupling surface of the adapter device is provided with a first and a second series of electrical connections which are electrically connected to electrical connections provided on the switch. The body of the adapter device comprises a lower surface and a front surface, each provided with electrical contacts. In more detail, the electrical contacts on one of the two surfaces are connected to the first electrical connections, while each contact on the other surface is electrically connected to one of the second electrical connections. The electrical contacts on the surfaces are mechanically and electrically connected to the branch of the distribution network which will be susceptible to be interrupted or not by the action of the switching device that will be connected to the adapter device. 
     This solution, just like many other similar ones, allows rapid connection of the switch to the adapter device. However, it presents evident limits as it does not allow rapid connection of the adapter device to the distribution network. In fact, this connection is conventionally realized through structural work which in many cases is extremely complex and which requires a considerable amount of resources. The use of prior art adapters also requires a considerable amount of space, above all due to the presence of intermediate copper joining elements (structural work). This drawback results in a substantial waste of useful volume inside the board, leading to a limit in the number of devices that can be installed. Moreover, once implemented, the installation solutions are not easily reversible; in other words, once a solution has been provided, it becomes final or inflexible, and is therefore extremely difficult to convert it into a different solution in the event of need. In this regard, it must also be remarked that subsequent operations to modify and adapt the structural work of a bus bar system inevitably result in deterioration of the conditions of safety and reliability (excessive presence of connecting screws and joining elements, faults in the correct clamping of each screw, modification of the original galvanic separations between phases. Moreover, in almost all cases installation of the adapter device requires prior disconnection of the power supply in the branch of the distribution network involved. In many cases, this condition forms a further limit, above all in certain applications, such as in ships and hospitals. 
     On the basis of these considerations, the main aim of the present invention is to provide an adapter device for electromechanical installation of a switching device which allows the aforesaid drawbacks of prior art to be overcome. 
     Within this aim, an object of the present invention is to provide an adapter device that can be installed rapidly in a low voltage system. 
     Another object of the present invention is to provide an adapter device which can be rapidly and effectively installed in a distribution bus bar system with horizontal or with vertical bus bars. 
     Another object of the present invention is to provide an adapter device which involves the use of negligible space, so as to be able to provide extremely compact installation solutions, also with adjacent switches placed mutually in contact, with the technical advantage of being able to install a very large number of devices. 
     Another object of the present invention is to provide an adapter device which is easily reversible, i.e. easy and fast to adapt when required, according to criteria of flexibility, to new installation solutions characterized by the presence of a different number and/or type of installed devices. 
     Another object of the present invention is to provide an adapter device which is easy to reposition according to countless configurations, without the need to make any modifications or additions to the original bus bar system, i.e. without the bus bar system being exposed to premature deterioration. 
     Yet another object of the present invention is to provide an adapter device to which a switching device can be operatively connected/disconnected in safe operating safety. 
     A further object of the present invention is to provide an adapter device which is reliable and relatively easy to produce at competitive costs. 
     This aim and these objects, as well as others which will be more apparent during the description, are achieved through an adapter device for connection of a low voltage switching device to a distribution bus bar system comprising:
         a substantially prismatic shaped body comprising a front wall, connectable to said switching device, and a back wall opposite said front wall, said body comprising first mutually opposite lateral walls and second mutually opposite lateral walls orthogonal to said first lateral walls;   first electrical terminals each of which is susceptible to electrically contact a distribution bus bar, said first electrical terminals emerging at least partly from said back wall;   second electrical terminals emerging from one of said first or of said second lateral walls;   first electrical connections each of which is electrically connected to one of said first electrical terminals, said first electrical connections which can be coupled with corresponding third electrical connections of said switching device;   second electrical connections each of which is electrically connected to one of said second electrical terminals, said first electrical connections which can be coupled with corresponding fourth electrical connections of said switching device;   a plurality of coupling terminals, at least partly emerging from said back wall of said body, to removably connect said adapter device to said distribution bar system, each of said first electrical terminals electrically contacting one of said distribution bus bars following the action of one of said coupling terminals.       

     The use of the coupling terminals allows rapid installation of the adapter device  1  in a distribution bus bar system regardless of the orientation thereof (vertical or horizontal). Unlike many conventional solutions, installation does not require any prior structural work with evident advantages in terms of labor and relative costs. This distinctive feature is particularly advantageous also in the event of it being necessary to provide new utilities even when it is not possible to disconnect the power supply to the distribution bus bar system. The advantages of the solution described are particularly evident in emergency situations, i.e. where it is necessary to provide a new utility with interruption or a new power source through interruption from or to a distribution bus bar system. 
     According to another aspect of the present invention, the configuration of the adapter device advantageously allows extremely compact installation solutions to be provided, even with adjacent switches placed mutually in contact, with the technical advantage of being able to install a very large number of devices. The adapter device is easily reversible, i.e. can be easily and rapidly modified if required, according to criteria of flexibility, to new installation solutions distinguished by the presence of a different number and/or type of installed devices. The adapter device can in fact be repositioned according to countless configurations, without the need to make modifications or additions to the original bus bar system, i.e. without the bus bar system being exposed to premature deterioration. 
    
    
     
       Further characteristics and advantages will be more apparent from the description of preferred but non-exclusive embodiments of the support base according to the invention, illustrated by way of non-limiting example with the aid of the accompanying drawings, wherein: 
         FIG. 1  is an exploded view of a switching unit formed by an adapter device and by a switching device according to the invention installable on a bus bar system; 
         FIG. 2  is a first perspective view of an adapter device according to the invention; 
         FIG. 3  is a front view of the adapter device of  FIG. 2 ; 
         FIG. 4  is a sectional view according to the line IV-IV of  FIG. 3 ; 
         FIG. 5  is a second perspective view of the adapter device of  FIG. 2 ; 
         FIG. 6  is a view of an adapter device according to the invention for electromechanical connection of a plug-in switching device in a distribution bus bar system; 
         FIG. 7  is a view of a switching device connectable to an adapter device according to the invention; 
         FIG. 8  is a perspective view of a switching unit comprising an adapter device according to the invention; 
         FIG. 9  is a schematic view of a switchboard comprising a plurality of adapter devices according to the present invention; 
     
    
    
     With reference to the aforesaid figures, the adapter device  1  according to the invention is produced so as to allow electromechanical connection of a switching device  2 , such as an automatic circuit breaker, to a distribution bus bar system  3 . In this regard, in the following description the switching device  2  will also be indicated with the expression “switch  2 ” without prejudice to the fact that the technical solutions described below are also valid for other types of switching device of the plug-in or withdrawable type for low voltage systems, such as disconnectors or contactors. Moreover, purely for descriptive purposes, the adapter device  1  will also be indicated with simpler expression “adapter  1 ”. 
     The adapter device  1  comprises a substantially prismatic shaped body  5  comprising a front wall  11  and a back wall  12  opposite the front wall  11 . The front wall  11  can be coupled with a corresponding coupling wall of a switch  2 . The body  5  of the adapter  1  comprises a first pair of mutually opposed lateral walls  13 ,  14  which extend between the front wall  11  and the rear wall  12  in a manner orthogonal thereto. The body  5  also comprises a second pair of mutually opposed lateral walls  15 ,  16  which extend between the front wall  11  and the back wall  12  also in a manner substantially orthogonal to the first lateral walls  13 , 14 . In a substantially vertical installation mode, the first lateral walls  13 ,  14  in practice correspond to a lower wall  13  and an upper wall  14  of the body  5 , while the second lateral walls  15 ,  16  form the flanks of the body. 
     The body  5  comprises first electrical terminals  41  (see  FIG. 2 ) each of which is intended to electrically contact a bus bar  3 B of a distribution bus bar system  3  and second electrical terminals  42  each of which connectable to an electrical conductor intended for connection to other parts of the system. With reference to  FIG. 3 , the body  5  also comprises first electrical connections  21 , each of which is electrically connected to one of the first electrical terminals  41 , and second electrical connections  22  each of which is electrically connected to one of the second electrical terminals  42 . The first  21  and the second electrical connections  22  are electrically connectable to corresponding third  23  and fourth electrical connections  24  of a switch  2 . As will be better explained below, the first  21  and the second connections  22  preferably present a “socket” configuration, while the third  23  and the fourth connections  24  of the switch present a “plug” configuration. 
     The first electrical connections  21  and the second electrical connections  22  are preferably aligned according to mutually parallel directions of alignment  100  (see  FIG. 3 ). These directions of alignment  100  are preferably parallel to the first lateral walls  13 ,  14  and substantially orthogonal to the second lateral walls  15 , 16 . In other words, the directions of alignment  100  are parallel to the base wall  13  and orthogonal to the flanks of the adapter  1  when this is considered with respect to the vertical installation mode of  FIG. 1 . 
     The adapter  1  according to the invention comprises a plurality of coupling terminals  8  which emerge at least partly from the back wall  12  of the body  5  to removably connect the adapter  1  to the distribution bus bar system  3 . Following the action of one of the coupling terminals  8  a corresponding first electrical terminal  41  comes into electrical contact with one of the distribution bus bars ( 3 B) (see  FIG. 4 ). 
     Each terminal  8  comprises a coupling portion  7  disposed in front of the back wall  12  at a distance such as to allow interposing of at least a portion  3 C of a distribution bus bar  3 B. Each coupling terminal  8  comprises reversible clamping means which drive the coupling portion  7  orthogonally to the back wall  12  to clamp the portion  3 C of the bus bar  3  between this coupling portion  7  and the back wall  12 . Following the action of said clamping means each of said first electrical contacts  41  electrically contacts one of said distribution bus bars  3 . 
       FIG. 1  shows an adapter device  1  according to the invention and a switch  2  connectable thereto. The front wall  11  of the adapter  1  comprises first hollow cylindrical bodies  26  each of which emerges in a position corresponding to one of the first electrical connections  21  and second hollow cylindrical bodies  27  each of which emerges in a position corresponding to one of the second electrical connections  22 . The cylindrical bodies  26 ,  27  have the purpose of creating a protection for the operators so that the first  21  and the second electrical connections  22  are not immediately accessible, but remain confined and isolated inside the body  5  of adapter device  1 . The cylindrical bodies  26 ,  27  preferably emerge from corresponding inserts  29  applied to the front wall  1  and advantageously act as a guide for insertion of the third  23  and fourth connections  24  of the switch  2  in the corresponding connections  21 ,  22  of the adapter  1 . 
       FIG. 2  is a first perspective view of an adapter device  1  according to the invention and allows observation in particular of the structure of the back wall  12  of the body  5 . According to a preferred embodiment of the invention, each coupling terminal  8  emerges from the back wall  12  with a corresponding coupling portion  7  so that this latter is at a different height H (calculated with respect to one of the first lateral walls  13 ,  14 ) and at a different distance D (calculated with respect to one of the second lateral walls  15 ,  16 ) with respect to those of coupling portions  7  of other terminals  8 . In the particular case shown in  FIG. 2 , the coupling terminals  8  emerge from the back wall  12  so that the corresponding coupling portions  7  are disposed diagonally with respect to this back wall  12 . The difference between the heights of two coupling terminals  8  is chosen as a function of the pitch of the distribution bus bar system  3 , or of the distance between the centers of these bus bars. 
     Again according to a preferred embodiment of the invention, each coupling terminal  8  comprises a pair of coupling portions  7  to advantageously increase the gripping surface and consequently improve the effectiveness of connection thereof. The use of two coupling portions  7  also allows improved distribution of the loads deriving from clamping, benefiting the integrity of the adapter  1 . The two coupling portions  7  are preferably operated by the same clamping means, but obviously could also be operated separately. 
     In the solution shown in  FIG. 4 , the first electrical terminals  41  are defined at least partly by the coupling portions  7  which are made of metal material. Through this solution, besides producing the mechanical connection, the coupling portion  7  advantageously also produces an electrical connection of the adapter device  1  to the distribution bus bar system  3 B. 
     Again in the solution of  FIG. 4 , each of the first electrical terminals  41  also comprises a conductive plate  41 B which emerges from the back wall  12  so as to occupy, at least partly, a position in front of the coupling portions  7  of one of the terminals  8 . Through this solution, once the clamping means are operated, the portion  3 C of bus bar  3 B advantageously remains between the coupling portion  7  and the conductive plate  41 B both made of conductive material. 
     The coupling portions  7  of the terminal  8  present a contact surface  7 B preferably serrated or knurled to increase the gripping effect on the corresponding portion  3 C of the distribution bus bar  3 B. It has been found that following clamping of the terminals, this technical solution allows a slight surface deformation of the bus bar  3 B to be achieved, accompanied by an increase of the conductive effect and of the mechanical seal. 
     With reference to the view of  FIG. 2 , the adapter device  1  preferably also comprises one or more insulating elements interposed between the coupling portions  7  of mutually adjacent terminals. In the solution shown, these insulating elements comprise a plurality of separators  75  each of which emerges from the back wall  12  of the adapter  1  in a position immediately adjacent to the coupling portion  7  of a terminal  8  so as to isolate these portions from those relative to the other terminals  8 . These separators  75  are preferably produced in one piece with the body  5  of the adapter  1  also made of insulating material. 
       FIGS. 3 and 4  are respectively a front view and a sectional view of the adapter device of  FIG. 2  and allow detailed observation of the internal structure of the body  5  of the adapter  1 . In particular, in these figures the inserts  29  and the relative hollow cylindrical bodies  26 ,  27  have been appropriately removed. With reference to the view of  FIG. 3 , the first  21  and the second electrical connections  22  are housed in appropriate seats  62  defined inside the body  5  and respectively aligned according to directions of alignment  100  defined above. The first  21  and the second electrical connections  22  preferably present a “socket” configuration so as to couple with respective third  23  and fourth electrical connections  24  of the switch  2  with “plug” configuration. In more in detail, in the solution illustrated, the electrical connections  21 ,  22  of the adapter  1  comprise a cylindrical body, hollow internally and divided into a plurality of longitudinal sectors  24 B mutually connected by elastic elements  24 C. These sectors define a cavity  96  (see  FIG. 4 ) inside which a connection with “plug” configuration of the switch  2  is inserted. The presence of elastic elements  24 C ensures contact between the surface of the cavity  96  of the “socket” connection and the external surface of the “plug” connection. The cylindrical body of the “socket” connection is in electrical contact with a collector  32  made of conductive material, which is in electrical contact with a corresponding electrical terminal  41  or  42 . 
     The sectional view of  FIG. 4  allows detailed observation of the electrical connection between a first electrical terminal  41  and a corresponding first electrical connection  21 . As shown, the first electrical terminal  41  comprises a shaped conductive bar  44 , a contact portion of which emerges from the back wall  12 . In particular, this contact portion preferably coincides with the aforesaid conductive plate  41 B of the first electrical terminal  41 . 
     The shaped conductive bar  44  extends inside the body  5  of the adapter device  1  and is mechanically and electrically connected to the collector  32  of a first electrical connection  21  through a fixing screw  69  which is coaxial with this connection or with the collector  32 . 
     In the solution shown in  FIG. 4  the part of the coupling terminal  8  emerging from the back surface  12  is substantially L-shaped with one side configuring the coupling portion  7 . The clamping means comprise at least one fixing screw  9  whose axis is substantially orthogonal to the back wall  12 . The fixing screw  9  engages with a threaded portion  8 B of the coupling terminal  8  substantially opposite the coupling portion  7  and so as to be inside the body  5  of the adapter  1 . The head  9 B of the fixing screw  9  is accessible to an operator by virtue of at least one appropriate cavity  38  (see  FIG. 3 ) defined in the internal structure of the body  5  of the adapter  1 . These cavities  38 , preferably cylindrical in shape, are advantageously produced in one piece with the body  5  of the adapter  1  and extend so as to define an obligatory path for the tool (such as a key or a screwdriver) which can be used to clamp the screw. 
     The end of the screw  9 C opposite the head  9 B contacts the internal surface of the conductive bar  44  which offers a stop surface during clamping of this screw. In particular, as a result of this stop surface the screw  9  remains axially locked and this determines relative movement of the threaded part  8 B of the terminal  8  or of the relative coupling portion  7  integral therewith. Consequently, the coupling portion  7  moves towards or away from (depending on the direction of rotation of the screw  9 ) the back wall  12 , producing or eliminating the clamping action on the corresponding distribution bus bar  3 B. 
     Again with reference to the sectional view of  FIG. 4 , the second electrical terminals  42  emerge from one of the first lateral walls  14 ,  15 , for example from the lower wall considered with respect to vertical installation of the adapter device  1 . Each of these second terminals  42  comprises a shaped element made of conductive material connected, preferably directly, to one of the second electrical connections  22  through screw fixing elements. In particular, this shaped element comprises a first external  42 B connectable to an electrical conductor (not shown) outside the adapter  1  and an internal portion  42 C connected to the collector  32  of a corresponding second electrical connection  22 . This latter connection is realized by second screw fixing means  71 . These means act so that the internal portion  42 C of the second terminal  42  remains clamped between the collector  32  and a mating element  39 . 
       FIG. 5  is a perspective view of the adapter  1  and allows observation of another distinctive feature thereof. In particular, the body  5  comprises first mating means which cooperate with second mating means of the switch  2 . In practice, these means have the function of guiding correct coupling between the switch  2  and the adapter  1 . 
     In the solution shown in  FIG. 5 , the first mating means comprise a drawer cavity  81  in which a guide plate  82  (shown at the side of the adapter  1 ), applied to the coupling wall  95  of the switch  2 , can be inserted. The drawer cavity  81  is dimensioned so that its internal walls contact the corresponding edges of the guide plate  82  so as to guide coupling according to a direction substantially orthogonal to the front wall  11  of the adapter  1 . 
     Again with reference to  FIGS. 3 and 5 , the adapter  1  advantageously also comprises first interlock means which cooperate with second interlock means of the switch  2  once this is coupled with the adapter  1 . In particular, these interlock means have the function of preventing removal of the connection between the two devices (switch  2  and adapter  1 ) when the switch  2  assumes a “closed” (ON) configuration. In other words, the switch can only be unplugged or withdrawn when it is in the “open” (OFF) or tripped positions. 
     In the solution shown, the first interlock means comprise a housing cavity  91 , in which a hook-shaped operating end  92 B of an interlock lever  92  (shown and indicated at the side of the adapter  1  in  FIG. 5 ) emerging from the back coupling surface  5  of the switch  2 , can be inserted. The cavity  91  is provided with a locking end  93  which couples the hook end  92 B of the interlock lever  92  when this is in a locked operating position. In this coupling condition, the switch  2  cannot be removed from the adapter  1 . Conversely, when the interlock lever  92  assumes a released operating position, corresponding to the open or tripped positions of the switch  2 , removal is possible as the operating end  92 B is released from the locking end  93 . 
     Again with reference to  FIG. 5 , the body  5  of the adapter device  1  advantageously also comprises one or more auxiliary cavities  94  in each of which it is possible to place accessory devices, such as position contacts, or accessories similar to those that can normally be placed inside the switch. In the solution shown the body  5  comprises, for example, a plurality of auxiliary cavities  94 , drawer-shaped and defined in one piece with this body. 
     According to a possible embodiment of the adapter  1 , at least one of the aforesaid second lateral walls  15 ,  16  is configured so as to allow positioning of first connector means (visible in  FIG. 8 ) suitable to couple with corresponding second connector means of the switch  2 . These connector means perform a supply and/or control function of accessory devices of the switch. 
     In the embodiment of  FIG. 5 , at least one of the lateral walls comprises guide and support grooves  83  which allow the first connector means  97  to be integrated in the structure of the body  5 . These support grooves extend according to the direction of coupling of the switch  2  to the adapter  1  to allow simultaneous coupling of the first connector means  97  to the corresponding second connector means  92  associated with a flank of the switch  2 . 
       FIG. 6  is a view of an adapter device  1  according to the invention to which an insertion device  30  is operatively connected to allow connection of a switch of withdrawable type to this adapter device  1 . The insertion device  30  comprises one or more sliding guides  33  for sliding of corresponding guide elements (not shown), provided on the flanks of the withdrawable switch  2  in order to facilitate coupling with/decoupling from the adapter  1 . The insertion device  30  also comprises a drive mechanism  36  responsible for movement of the switch  2  along the sliding guides  33 . 
     The insertion device  30  is preferably connected to one of the second lateral walls  15 ,  16  of the body  5  of the adapter  1  so that the sliding guides  33  are positioned according to the correct direction of insertion. The drive mechanism  36  is operated by an operator preferably through an operating crank  58  once the switch  2  has been coupled with the mechanism. 
     The present invention also relates to a single-pole or multi-pole switching device  2  comprising a case housing therein, for each pole, at least one moving contact and at least one fixed contact, which can be coupled with and decoupled from each other.}0} {0&gt;&lt;}0 {&gt;The switching device  2  is characterized in that it comprises a coupling wall  95 , which can be coupled with a front wall  1  of the adapter device  1  according to the invention. 
       FIG. 7  is a perspective view of the switch according to the invention showing in particular the back coupling wall  95  of the switch  2 . This switch  2  comprises third electrical connection means  23  and fourth electrical connection means  24 , each with “plug” configuration to be inserted and connected respectively with first  21  and second connections  22  with “socket” configuration, as already indicated above. 
     The third  23  and the fourth connections  24  are aligned according to mutually parallel directions  110  and spaced apart by the same distance between the first  21  and the second electrical connections  22  of the adapter  1 . The third  23  and the fourth electrical connections  24  are preferably formed from a single piece of copper (or other equivalent conductive material) of cylindrical configuration and with a diameter so as to allow insertion in the cavity  96  defined by the body of a corresponding electrical connection  21 ,  22  of the adapter  1 . The third  23  and the fourth electrical connections  24  with “plug” configuration also comprise a hexagonal cavity  77  to facilitate mounting of these plugs. 
     Again with reference to the view of  FIG. 7 , the switch  2  comprises second mating means which cooperate with the first mating means of the adapter  1  to allow correct coupling thereof. The second mating means comprise a guide plate  82  which emerges from the coupling wall  95  of the switch  2  orthogonal thereto. The guide plate  82  forms a first side of an L-shaped element which is connected to the coupling wall by a second side  84 . 
     The switch  2  according to the invention also comprises second interlock means, which cooperate with the first interlock means of the adapter according to the methods defined above. With reference to the aforesaid indications on this subject, the second interlock means comprise an interlock lever  92  provided with a hook-shaped end  92 B which engages, in a locked position, with a locking end  93  of the first interlock means of the adapter  1 . The interlock lever  1  is operatively connected to the contacts of the switch or to other parts of the control, in any case so that its position is significant of the position of the moving contacts, or of the configuration (open, closed, tripped) of the switch  2 . 
     The present invention also relates to a switching unit  99  formed of an adapter  1  according to the invention and a switch  2  according to the invention which can be removably coupled with the adapter  1 . In this regard,  FIG. 8  shows a switching unit  1  formed by a three-pole switch  2  electromechanically coupled with a four-pole adapter  1  to show the functional versatility of the adapter  1  according to the invention. In other words, switching devices having a different number of poles can also advantageously be connected to the adapter  1 . 
       FIG. 8  allows observation of coupling between first connector means  97  associated with a flank of the adapter  1  and corresponding second connector means associated with a flank of the switch  2 . The connector means can, for example, comprise plugs, cables, insertion sockets, etc., or other equivalent means, according to need. The first connector means  97  of the adapter are connected downstream to the second connector means  92  of the switch  2  and can be connected upstream to a power supply system or to other electrical devices. 
       FIG. 9  is a view of a switchboard  88 , inside which a bus bar system  3  with vertical configuration is placed. The technical solutions indicated above allow installation of the adapter  1  regardless of the orientation of the bus bar system  3 . The adapter  2  can in fact be mounted on a horizontal bus bar system, as shown by way of example in the solution in  FIG. 1 , but also on a vertical bus bar system as shown clearly in  FIG. 9 . It is observed that besides rapid installation, the internal configuration of the switchboard  88  is particularly orderly and without rough joints to the bus bar system with evident advantages, for example of safety and reliability, and relative to inspection and maintenance operations. In particular, the reduced dimensions of the adapters and the absence of means interposed between adapters and adjacent switching units allows extremely compact installations to be obtained, also with the single utilities placed in direct contact with one another. 
     The technical solutions adopted for the adapter device according to the invention allow the aim and the objects set to be fully achieved. In particular, these solutions allow rapid and flexible installation of the adapter to a distribution bus bar system without requiring any prior structural work on these bus bars. At the same time, the technical solutions are such as to make the adapter extremely safe and reliable with very competitive production costs. 
     The adapter device thus conceived is susceptible to numerous modifications and variants, all falling within the inventive concept; moreover all details can be replaced by other technically equivalent details. 
     In practice, the materials used and the contingent dimensions and forms can be any, according to requirements and to the state of the art.