The invention is related to an apparatus for facilitating the mounting electrical com ponents in a switchgear and a switchgear including such an apparatus according to the preamble of claims 1 and 11.

In the field of switchgears, in particular low voltage switchgears, it is sometimes re quired to replace a defective electrical component inside the switchgear. In switch- gears having a back plane which is configured as a laminated busbar, the mounting and the dismounting of the electrical component has to be done through the front opening of the housing which requires a lot of physical strength for the operator when heavier components like devices including electrical transformers and coils etc. have to be precisely positioned relative to the electrical contacts of the busbar.

An even bigger problem arises if in case of a mechanical or electrical failure, the lam inated busbar itself has to be removed and afterwards reinstalled inside the housing of the switchgear, because due to its sandwich construction of metal sheets and rein forced fiber layers, the weight of such a bus bar can easily amount up to 50 kg or more, depending on the size.

An afore mentioned switchgear having a housing with a backplane which is formed as a laminated busbar is e.g. described in GB-A 01030283. Another example for a busbar in which the different layers are laminated to each other by means of liquid resin is described in DE 10 2005 015 945 B4 of the applicant. Accordingly, it is a problem of the present invention to provide an apparatus which allows for an easy mounting and demounting of electrical components and devices inside a switchgear including a laminated multi-phase busbar.

This problem is solved by an apparatus as claimed in claim 1.

A further problem of the invention is to provide a switchgear, in particular a low volt age switch gear, having a housing with a front opening and a laminated busbar mounted therein, which allows for an easy and fast mounting and demounting of even heavy electrical components to/from the busbar or even of the entire busbar itself, inside the housing.

This problem is solved by a switchgear as claimed in claim 11.

Further objects of the present invention are included in the dependent claims.

The invention is hereinafter described with reference to the accompanying drawings. In the drawings:

Fig. 1 a is a schematic 3-dimensional view of a switch gear with omitted side walls in which an apparatus according to the present invention is installed,

Fig. 1 b is a schematic side view of the switch gear of Fig. 1 a,

Fig. 1 c is a schematic front view of the switch gear of Fig. 1 a with a further em bodiment of the apparatus according to the present invention, in which the length of an elongated carrier element is variable by means of a tensioning device,

Fig. 2 is a 3-dimensional view of separated first and second rail with inserted runners each carrying a mounting plate with an opening formed therein for connecting the lower end portions of an elongated carrier element, Fig. 3 is an enlarged front view of the first and second rail with inserted runners, and

Fig. 4 is a schematic view of a tensioning device including a roll-up reel and a ratchet for varying the length of a strap-type elongated carrier element.

As it is shown in Figs. 1 to 4, an apparatus 1 for facilitating the mounting of electrical components 102 in a switchgear 100 comprises a first and a second rail 2a, 2b which are adapted to be mounted in parallel to and spaced apart from each other in the interior of a housing 110 of the switch gear 100. The housing of the switch gear 100, which is preferably a low voltage switch gear, comprises side walls 110a (only shown in Fig. 1 c), a top wall 110b and a front opening 112 which is defined between the side walls 110a. Inside the housing 110, a busbar 114, preferably a laminated multi-phase busbar, is accommodated in a plane opposite to the front opening 112, which may serve as a back plane or back wall of said housing.

As it can further be seen best from Fig. 1a 1 b and 1 c, the first and the second rail 2a, 2b extend in a substantially horizontal direction between the front opening 112 and the busbar 114 and are mounted to a frame 116 of the housing, to which the busbar 114 and panels forming the side walls 110a and the top wall 110b are attached. In the preferred embodiment of the invention, the frame 116, to which the side walls 110a and the top wall 110b may be removably attached by means of screws or bolts, preferably comprises vertical frame posts 116a, 116b, to which the first rail 2a and also the second rail 2b can be mounted by means of screws, hooks, bolts or any oth er type of known fastening elements, in order to allow for a fast and preferably tool- free mounting and removal of the rails 2a, 2b if desired.

As it is further shown in detail in Figs. 1 , 2 and 3, a first and a second runner 4a, 4b, which are adapted to be received in the first and second rail 2a, 2b, respectively, is arranged in each of the first and second rail 2a, 2b and is movable along the associ ated rail 2a, 2b in a direction away from the front opening 112 towards the busbar 114 at the rear end of the housing 110 and vice versa. As it can be seen from Fig. 1 c and Fig. 3, the runners 4a, 4b may comprise a pair of track rollers which are rotatably mounted at a distance to each other at a mounting plate 20. The apparatus 1 further comprises a first and a second elongated carrier element 6a, 6b which is shown in Fig. 1 a - 1 c and which comprises an upper end portion 8 and a lower end portion 10. The upper end portion 8 of the first elongated carrier element 6a is connected to the first runner 4a, whereas the upper end portion 8 of the second elongated carrier element 6b is connected the second runner 4b. The coupling of the upper end portions 8 of the first and second elongated carrier elements 6a, 6b to the first and second runner 4a, 4b is preferably achieved by means of the mounting plates 20, as it is illustrated in Fig. 1a.

The lower end portion 10 of the first elongated carrier element 6a comprises a or is coupled with a first connecting element 12a, and the lower end portion 10 of the sec ond elongated carrier element 6b comprises a or is coupled with a second connect ing element 12a, which may e.g. be an eyelet, as it is shown in the exemplary em bodiment of Figs. 1 a to 1 c, a hook, a clamp or any kind of known fastening device which is suitable to couple the lower end portion 10 to an electric component 112. In other words, the first and second connecting elements 12a, 12b are adapted to be connected to the electrical component 102 which is to be mounted to the busbar 114.

By means of the apparatus 1 of the present invention, the weight-force of the electri cal component 102 is transmitted via the first and second elongated carrier elements 6a, 6b and the first and second runners 4a, 4b into the first and second rail 2a, 2b and from there into the frame 116 of the housing 110, which allows the electrical component 102 to be pushed by hand through the front opening 112 towards the busbar 114. Due to the low frictional forces between the runners 4a, 4b and the rails 2a, 2b, the movement of the component 102 inside the housing 110 only requires a low pushing or pulling force but no additional holding force of the component, which advantageously allows for a very precise positioning of even very heavy components like the busbar 114 itself.

According to a further object of the present invention, the length of the first and pref erably also the second elongated carrier element 6a, 6b is adjustable. This provides for the advantage that the vertical position, as well as the lateral position of the elec tric component 102 can be adapted to the desired mounting position of the compo- nent at the busbar 114 which allows an even more precise positioning of the compo nent inside the housing 110.

In a preferred embodiment of the invention, the first and preferably also the second elongated carrier element 6a, 6b is a tensioning strap or a tie rope.

Although the first and second carrier element 6a, 6b can also be steel rods having threaded male portions which may be received in associated threaded female openings formed at the runners 6a, 6b or the connecting elements 12a, 12b, in order to allow an adjustment of the length thereof, tensioning straps or ropes have the advantage of a low weight and a compact design. A further advantage of using tensioning straps can be seen in that due to the width of the straps, there is an improved support of the load in the moving direction which reduces the danger of a tilting of the load if it is supported below the center of gravity.

According to a further object of the invention, the tensioning strap or tie rope comprises a tensioning device 14 which preferably includes a known roll-up reel 16 and a ratchet 18, as it is schematically shown in Fig. 4. The usage of tensioning straps or belts with integrated tensioning devices, as they are known in the art for securing loads like motor bikes on trailers etc., provide for the advantage that due to the very flat design of the straps, the length thereof can be altered in a wide range by rolling up the straps. Moreover, by operating the tensioning device 14, which usually comprises a handle 14a and a releasable prawl or ratchet 18 (see Fig. 4), the vertical position as well as the lateral position of the electric component 102 can be precisely adjusted while the component is suspended from the two straps which in this case form the first and second elongated carrier element 6a, 6b.

In an even more sophisticated embodiment of the invention, which is shown in Fig. 3, the first and the second rail 2a, 2b may be adapted to be mounted in a V-shaped configuration inside the housing 110 in such a way that the axis of rotation of the track rollers of the first and second runner 4a, 4b is inclined towards the horizontal direction, so that the axes of rotation of the track rollers of both runners 4a, 4b are inclined at an angle to each other. The angle of inclination of the axes of rotation toward each other may be in the range between 1 ° and 15 ° or even more. The inclined mounting of the rails 2a, 2b provides for the advantage that the forces acting on the runners in a lateral direction are minimized or even eliminated, which in turn results in a reduced friction and wear of the rails/runners. Moreover, the construction of the rails 2a, 2b and runners 4a, 4b can be simplified, because no additional bearing is required which takes up the lateral forces that may urge the runners 4a, 4b to jump out of its associated rail 2a, 2b.

In order to further reduce the risk of the runners 4a, 4b being urged out of the rails 2a, 2b, the first and/or second rail 2a, 2b may comprise a housing which, when seen in the longitudinal direction of the rail 2a, 2b, grasps around the upper side and the lower side of the first and second runner 4a, 4b, respectively, so that the first and second runner 4a, 4b is guided inside its associated rail 2a, 2b in a from locking manner.

As it is further shown in Fig. 2, the mounting plate 20 preferably comprises an open ing 20a formed therein, to which an upper end portion 8 of the first and second elon gated carrier element 6a, 6b may be coupled in an articulated manner. In the em bodiment in which the elongated carrier elements 6a, 6b are configured as straps or ropes, the articulated coupling may be obtained by simply pulling the strap or rope through the opening 20a. The articulated coupling has the advantage that a lateral positioning of the electric component 102 can be obtained in a mechanically simple and cheap way.

In order to allow for an easy and comfortable attachment of the electric component 102 to the apparatus 1 , the first and the second rail 2a, 2b may be configured as a known telescopic rail which can be expanded from a retracted state or position to an expanded state or position. In this embodiment of the invention, the length of each of the rails 2a, 2b is such that in the contracted state, the rails 2a, 2b are completely received inside the interior of said housing 110, whereas in the expanded state, the end portions of the rails 2a, 2b project out of the housing 110 through the front open ing 112, as it is shown in Fig. 1 a and 1 b. Listing of reference numerals

1 apparatus

2a first rail

2b second rail

4a first track roller

4b second track roller

6a first elongated carrier element

6b second elongated carrier element

8 upper end portion of elongated carrier elements

10 lower end portion of elongated carrier elements

12a first connecting element

12b second connecting element

14 tensioning device

14a handle

16 roll-up reel

18 ratchet

20 mounting plate

20a opening

100 switch gear

102 electrical component

110 housing of switch gear

110a side walls

110b top wall

112 front opening

114 busbar

116 frame

116a, b vertical frame posts