Abstract:
A window unit installed on a trim element of a switchgear cabinet. The window unit contains a window element that is coupled to the trim element in pivoted fashion. In order to allow a simple mounting of the window unit on the trim element, a frame is attached to and mounted on the trim element, and the window element is hinged to the frame.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a window unit that is installed on a trim element of a switchgear cabinet, wherein the window unit contains a window element that is coupled to the trim element in a pivoted fashion. 
     2. Description of Prior Art 
     Window units of this type contain a window pane that is bordered by a frame along its edges, wherein the frame carries hinges. Openings are arranged in the trim element in order to attach the window unit. The hinges are inserted into the openings and subsequently mounted therein. The trim element contains a cutout behind the window pane. On a rear side of the trim element, a box covers the cutout, in which electrical components are accommodated. These installations are visible through the window pane of the window element and can, if so required, be accessed when the window unit is open. 
     The attachment of such a window unit needs to be carried out carefully. The hinges need to be arranged on the trim element in such a way that the hinge axes are aligned with one another. This means that it is relatively complicated to retrofit an existing switchgear cabinet with a window unit. In addition, the cutout in the trim element disadvantageously affects the stability and stiffness of the trim element. 
     SUMMARY OF THE INVENTION 
     This invention is based on one objective of developing a window unit of the initially mentioned type which can be easily mounted on a trim element. 
     This objective is achieved with a frame that is attached to and mounted on the trim element, and the window element is hinged to the frame. The frame as well as the window element hinged thereon form one structural unit that can be premanufactured. This structural unit can then be attached to the trim element, for example, by means of screws. This can be easily realized because no special dimensional tolerances need to be observed. Consequently, an existing switchgear cabinet can be easily retrofitted with a window unit. If a cutout is provided in the trim element, the frame stiffens the trim element. 
     The frame which is mounted on the trim element has a stiffening effect, for example, a cutout does not or only insignificantly impairs the stability of the trim element. 
     However, it is not absolutely imperative to arrange a cutout in the trim element for the window unit according to this invention. The frame may be realized in such a way that it holds the window element at a distance from the front side of the trim element. In this case, mounting and installation space is created in front of the trim element. 
     According to one preferred embodiment of this invention, the window element contains a window pane that has edge profiles on at least two sides, wherein one edge profile carries hinges for connecting the window pane to the frame, and wherein the second edge profile has a locking device. In this case, the edge profiles may be realized in the form of separate parts that can be subsequently fastened to the window pane, for example, by bonding. However, it would also be conceivable to directly incorporate the edge profiles on the window pane. 
     In another variation of this invention the frame carries a mounting plate that is arranged parallel to and at a distance from the window element in the closed position of the window element and can be equipped with electric components. The mounting plate can be separately equipped and wired. Subsequently, the mounting plate can be attached to the frame. The formed window unit can then be attached to the trim element. The mounting plate may, for example, also have an engraved or printed circuit at the manufacturing site. 
     In order to increase the installation space surrounded by the window unit, it would be conceivable to install a spacer frame on the frame. In this case, the spacer frame holds the mounting plate parallel to and at a distance from the closed window element within its region that faces away from the frame. 
     In order to achieve an appealing optical appearance, in one embodiment of the window unit according to this invention, the frame is inserted into the cutout of the trim element, wherein the frame adjoins the front side of the trim element around the cutout with a circumferential, laterally protruding edge. 
     In order to simplify mounting of the window unit, a tubular door frame may be fastened to the rear side of the trim element that is realized in the form of a cabinet door, wherein the tubular door frame contains a pattern of fastening receptacles, and wherein fastening screws extend through the fastening receptacles and are screwed into the frame. The fastening receptacles of the tubular door frame are used as a drilling template for the frame because the fastening receptacles of the frame need to be adapted to the pattern of fastening receptacles on the tubular door frame. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention is described in greater detail below with reference to one embodiment that is illustrated in the figures, wherein: 
     FIG. 1 is a perspective view of a switchgear cabinet with an exploded view of a window unit; 
     FIG. 2 is a perspective view of a switchgear cabinet according to FIG. 1 with an exploded view of a window unit; 
     FIG. 3 is an enlarged partial horizontal section taken through the edge region of the window unit according to FIG. 1; and 
     FIG. 4 is an enlarged partial horizontal section taken through the edge region of the window unit according to FIG.  2 . 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 shows a schematic representation of the cabinet body  10  of a switchgear cabinet. The cabinet body  10  has trim elements  11  on its sides. A window unit can be fastened to the front trim element  11 , for example, the cabinet door. In this case, the window unit comprises a frame  13 , a window element  12  and a mounting plate  17 . The frame  13  contains four profile sections  13 . 2  that are connected to one another in the corners of the frame by means of corner elements  13 . 1 . The cross-sectional shape of a profile section  13 . 2  is illustrated in greater detail in FIG.  3 . According to FIG. 3, a profile section  13 . 2  is formed as an extruded profile. On its side that faces the trim element  11 , the profile section  13 . 2  contains two grooves that extend in the longitudinal direction of the profile section  13 . 2  and serve as thread receptacles  13 . 3 ,  13 . 4 . Within a region in which it adjoins the trim element  11 , the profile section  13 . 2  has a seal receptacle  13 . 5 . A seal  12 . 6  can be inserted into this receptacle. On its side that faces away from the trim element  11 , the profile section  13 . 2  has one additional seal receptacle  13 . 5  formed as of a groove. A seal  12 . 6  that seals the window unit  12  can be inserted into the receptacle  13 . 5 . 
     FIG. 1 also shows that the window element  12  contains a window pane  12 . 1  having edge profiles  12 . 2 ,  12 . 3  on both vertically extending edges. The edge profile  12 . 2  carries a locking device  12 . 4 . The locking device  12 . 4  may, for example, carry a two-way key bit equipped with a sash fastener. In the closed position, this sash fastener engages behind a corresponding edge of the frame  13 . The edge profile  12 . 3  is equipped with hinges  12 . 5  as shown in FIG.  3 . The hinges  12 . 5  are fastened on the corresponding vertical profile section  13 . 2  of the frame  13 . The vertically extending hinge axis is held in front of the profile section  13 . 2  in this case. Due to this measure, the window element  12  can be pivoted open about 180°. Consequently, optimal access to the mounting space surrounded by the frame  13  is ensured. 
     The mounting plate  17  can be fastened on the frame  13 . For this purpose, the mounting plate  17  has recesses  17 . 1  on its edge. Fastening screws that extend through the recesses  17 . 1  can be screwed into the thread receptacle  13 . 4  of the profile sections  13 . 2 . In order to simplify the attachment of the mounting plate  17 , the frame  13  has an inner receptacle, the dimensions of which are adapted to the outer geometry of the mounting plate  17 . Electrical components may be accommodated on the mounting plate  17 . These electrical components can be mounted and functionally wired to one another before the mounting plate  17  is attached. The unit comprising the window element  12 , the frame  13  and the mounting plate  17  can then be fastened on the trim element  11 . FIG. 3 also shows that the trim element  11  which is formed as a cabinet door in this embodiment contains a circumferential angled section  11 . 1  on its edge. A seal  11 . 2  is formed onto the inner side of the trim element  11  parallel to and at a distance from this angled section  11 . 1 . Adjacent to this seal  11 . 2 , a tubular door frame  11 . 3  stiffens the trim element  11 . The tubular door frame  11 . 3  contains two vertical crossbeams that have a pattern of fastening receptacles in the longitudinal direction. These fastening receptacles serve as a drilling template for attaching the window unit. Fastening screws  11 . 4  can be inserted into the fastening receptacles of the tubular door frame  11 . 3  and screwed into the thread receptacles  13 . 3  of the frame. Consequently, the frame  13  is reliably and rigidly fixed in the trim element  11 . 
     FIG. 2 shows an expanded window unit. According to this embodiment, the window unit is supplemented with a spacer frame  15 . The spacer frame  15  comprises four extruded profiles. The spacer frame  15  contains a wall  15 . 1 , from which an edge  15 . 2  protrudes. The spacer frame  15  can be inserted into a cutout  16  in the trim element  11 . The fastening of the spacer frame  15  on the frame  13  is shown in greater detail in FIG.  4 . According to FIG. 4, the spacer frame  15  contains a flange  15 . 3  that has fastening receptacles within an end region that faces the frame  13 . Fastening screws  18  can be inserted into the fastening receptacles and screwed into the thread receptacles  13 . 4  of the frame  13 . The wall  15 . 1  of the spacer frame  15  increases the installation depth of the window unit. The rear side of the spacer frame  15  can be closed with the mounting plate  17 . For this purpose, thread receptacles  18  are machined into the edge  15 . 2 . Fastening screws  18  extend through recesses  17 . 1  in the mounting plate  17  and can be screwed into the thread receptacles of the edge  15 . 2 .